March 7, 1967
L. PERAS
3,307,455
HYDRAULIC DEVICES
EQUIPMENT
FORRAISING
FARMING AND
TRACTORS
STRESS-CONTROL
Filed March- 2,
1964
'
‘
3 Sheets-Sheet 1
Invenlor
Lucien per-'65
8/ fm, MM WJ/W/MM
mgifzowneyg.
March 7, ‘1967
'
7
~
|_.' PE As -
3,307,455
HYDRAULIC EQUIPMENT RAISING AND STRESS'CONTROL
DEVICES FOR FARMING TRACTORS
‘
Filed March 2, 1964
5 Sheets-Sheet 2
' Hg- 4
I
r
I
/_
2%
,
Im/ehZ/w
Lac fen pe ma 8
8/’
022%.”
1415 iorneiyg
March 7, 1967
“
L. PERAS
3,307,455
HYDRAULIC EQUIPMENT RAISING AND STRESS-CONTROL
DEVICES FOR FARMING TRAGTORS
Filed March 2, 1964
,
' 3 Sheets-Sheet 5
1391
g7
-
'
437
384D173 P
180
v
' 105
409
41%?
MM.
428. 3I65
Imus/i140!“
Lucien ‘paras
United States Patent 0 ice
1
3,307,455
Patented Mar. 7, 1967
2
is based on this second solution, the equipment raising
3,307,455
cylinder is connected to a distributor comprising a slide
CONTROL DEVICES FOR FARMING TRACTORS‘
valve for controlling the delivery of hydraulic ?uid from
HYDRAULIC EQUIPMENT RAISING AND STRESS
Lucien Peras, Billancourt, France, assignor to Regie
Nationale des Usines Renault, Billancourt, France, a
French works
Filed Mar. 2, 1964, Ser. No. 348,540
Claims priority, application France, Mar. 4, 1963,
926,788, Patent 1,363,918; Sept. 16, 1963, 947,625,
Patent 1,37 6,690
14 Claims. (Cl. 91-367)
This invention relates to hydraulic devices adapted to
raise the equipment or tool carried by farming tractors,
a source of ?uid under pressure such as a pump either
to said raising cylinder through an inlet valve in a ?rst
position of the movable member of said slide valve or
from said equipment raising cylinder through an exhaust
valve to an exhaust duct connected to the reservoir feed
ing said source in the second position of said slide valve
10 in which the movable member of the slide valve is urged
by spring means, or directly to said exhaust valve in the
intermediate position of the aforesaid movable member
of the slide valve. Moreover, this movable member of
to transfer the equipment load to the tractor, and to
the slide valve may assume other intermediate positions
control the tractive effort exerted on the equipment. It 15 in which, instead of causing the complete closing or
applies notably to tractors of the type comprising a single
opening of the ports concerned, it produces a more or less
acting hydraulic equipment-raising cylinder controlling
pronounced throttling thereof.
The desired position of the equipment raising arm is
nected through links to the traction rods carrying the
obtained by means of a preselector control arrangement
20 incorporating a preselector handlever and interconnected
equipment, tool or implement of the tractor.
one or a plurality of lifting arms having their ends con
This invention relates more particularly to a device
comprising in combination a preselector-type control in
through suitable linkage means with this handlever, the
slide valve and the raising arm.
the form of a preselector handlever adjustable as a func
An effort control system co-operates with the slide
tion of the desired vertical or depth position of the equip
valve and is connected to the draw-gear or coupling sys
ment, and another control of the tractive-effort type, i.e. 25 tem incorporating resilient means responsive to the trac
responsive to the resistant stress produced by the equip
tive effort when the latter exceeds a predetermined value.
ment during the ploughing or other soil-working opera
This effort control system comprises a ?rst pivoting bear
tion, this last-named control ‘being adapted to limit this '
ing member so arranged that the draw-gear may exert
stress to a preselected value by acting upon the tool oper
therethrough a certain force on the slide valve in the
ation depth, that is, upon the raising device proper, so 30 direction of the ?rst position thereof. The permissible
that the tractor will operate with a predetermined con
movement of said bearing member in the direction of
stant or maximum tractive effort.
this force is limited by an adjustable stop member pro
It is an object of this invention to provide a speci?c
vided on an adjustment handlever.
form of embodiment of a dual-control device of the type
The linkage means comprise a second pivoting bearing
broadly set forth hereinabove, which is characterized by 35 member also adapted to act upon the slide valve.
a greatly simpli?ed construction and by a considerable
The operative connections between said ?rst pivoting
degree of manoeuverabiiity, the operator having further
bearing member and the draw-gear, on the one hand,
more the choice of using only one of the two control
the between said second pivoting bearing member, said
means available in the device.
raising arm and said preselector handlever, on the other
Generally, two solutions may be resorted to for con
hand, are so designed that a tractive effort exerted on
the draw-gear which has a force sufficient to overcome
trolling either the tractive eifort of the tractor vehicle or
the resistant effort of the equipment during its operation:
the resistance of the resilient means, the movement of
said preselector handle in one direction as Well as the
(a) The ?rst solution consists in creating in the equip
lowering of the raising arm, are capable of causing the
ment raising cylinder pressure values determined before
slide valve member to move in the direction of its ?rst
hand as a function of the type of work to be performed,
position. Conversely, if this tractive effort decreases to
these pressure values being obtained whenever the trac
a value sul?cient to render the tractive eifort exerted by
tive effort rises to certain predetermined corresponding
said resilient means preponderant, a displacement of the
values;
This ?rst solution requires a nearly constant throttling
of the hydraulic ?uid, as a rule oil, in an open-center hy
draulic circuit, i.e. a circuit wherein a distributor having
at least three ports or ways provides a continuous ?uid
?ow from the ?rst port to the second and/ or third ports.
(b) The second solution consists in causing automati
cally a slight upward movement of the equipment each
time the resistant effort increases by a predetermined
value in order to decrease this resistant effort and there
fore reduce to zero the equipment-raising control action
in conjunction with the stabilization of the working depth
of the equipment at a value consistent with or correspond
ing to a given tractive effort.
preselector handlever in the opposite direction, a dis
placement of the adjustment handlever in the direction
to enable its stop member to exert a pressure against the
?rst pivoting bearing member and an upward movement
of the raising arm, will cause .the slide valve to move
toward its second position.
This invention is also concerned with a distributor
device of which the slide valve is responsive to the
various mechanical control elements set forth herein
above.
'
This distributor device comprises essentially inlet and
exhaust valves, a cock adapted to connect the source of
hydraulic ?uid under pressure directly to the feed reser~
voir of said source, a controlled relief valve and a dis~
Conversely, when the tractive effort decreases, the effort
tributor proper.
detecting device will control automatically the means for
lowering the equipment in order to increase the working 65 The cock is controlled from a double-acting cylinder
the inner space of which is divided by its piston into a
depth of the equipment until the preselected tractive effort
closing chamber containing a spring urging said piston
is restored.
in the cock closing direction and an opening chamber
This second solution is advantageous in that the feed
pump operates only during the equipment raising periods
connected to said source of hydraulic ?uid under pres
for altering the working depth, without requiring a con 70 sure, whereby the application of this pressure in this
stant throttling of the ?uid.
opening chamber will drive said piston in the cock open
In the device according to the present invention, which
ing direction.
‘
3,307,455
4
3
Said relief valve comprises a piston-like shutter open
ing with one end into a cavity into which a sliding valve
seat is also adapted to open. This sliding seat com
a farming equipment such as a plough are pivotally
mounted by means of their pivot pins 2 on the crank-pins
3 of a crankarm 4 adapted to rotate about a mainshaft
municates with the exhaust duct and is urged by spring
5 mounted in the casing of the ?nal drive of the tractor.
means toward said shutter of which the other end opens
into a control chamber adapted to be connected either
to the source of hydraulic ?uid under pressure or to said
The traction rods 1 are suspended from a lifting link 6
pivoted on the end of a lifting arm 7 rigid with a control
discharge duct.
The distributor proper comprises around its slide valve
said casing. An equipment raising cylinder 10 of which
lever 8 pivotally mounted on a spindle 9 ‘also carried by
the movable element or piston bears through the medium
member a ?rst chamber communicating with the source 10 of a thrust ‘rod 11 against the end of one of the arms of
said lever 8 exerts on the lifting arm 7 and raising link
of hydraulic ?uid under pressure, a second chamber com
6 a stress counter-acting the ‘force tending to lower the
municating with the raising cylinder through said inlet
valve, with the closing chamber of said cock and with
equipment.
The c-rankarm 4 is rigid with another lever 12 of which
municating with said control chamber of said relief valve 15 the permissible angular amplitude is limited by stop mem
bers 13 and 14. A traction spring 15 constantly urges
and with said discharge duct. These three chambers dis
posed around the slide valve are separated from each
the lever 12 towards the stop 13, i.e. in a direction op
posite to the direction in which this lever is urged by
other by two partitions disposed the one between said
the tractive force exerted ‘by the equipment.
?rst and second chambers, and the other between said
A ?rst ‘bearing member 16 in the form of a bell~crank
second and third chambers.
20
The slide valve incorporating said valve shutter dis
lever pivoted on the end of lever 12 by mean-s of a pivot
posed in said second chamber is adapted to close an
pin 17 and adapted to pivot in the same directions as this
ori?ce formed through said ?rst partition and is con
lever, has its free end registering with the control member
nected through an axial stem to a piston-type shutter
or push-rod 18, another tension spring 19 urging this free
disposed at the level of saidthird chamber arid adapted 25 end for engagement with the aforesaid push-rod, as shown.
to close either a passage formed through said second
The permissible angular movements of this ?rst bearing
partition or a passage leading to the discharge duct. The
member 16 is restricted, in the direction in which it is
distance between the seat of the valve shutter and the
urged by the spring 19, due to the provision of an ad
edge of the port into which said seat opens into said
justable stop 20, consisting for example of the loosed
the cavity of said relief valve, and a third chamber com
third chamber and the distance between the shutters are
so calculated that in the ?rst position the slide valve will
free the passage between said three chambers, that in the
second position it will prevent the communication be
tween these chambers and that in the intermediate posi
tion it will free only the passage between the ?rst chamber
and the second chamber. The duct connecting the
‘bottom of an axial blind bore of a tube 21 pivoted on
a lever 22 rigid with a control handlever 23 pivotally
mounted on a ?xed pivot pin 24, this blind bore being
engaged by a rod 25 pivotally mounted on said ?rst
bearing member 16.
A cam 26 of which the operative contour registers
equipment raising cylinder to the inlet valve communi
cates with the discharge duct through the medium of the
likewise with said push-rod 18 is pivotally mounted on a
?xed pivot pin 27. A ?rst rod 28 is pivoted at one end
on a point of said cam which is spaced from its axis of
exhaust valve the opening of which is controlled me
rotation and at its other end on an intermediate point of
chanically by the slide valve member when it is moved 40 another ‘rod 29 also pivoted at one end on the arm of con
to its second position.
trol lever 8 which is opposite to that engaged by the
Two typical forms of embodiment of the hydraulic
thrust rod 11. The other end of rod 29 is connected
raising device according to this invention are described
through a third pivoted rod 30 to one end of a lever
hereinafter by way of example with reference to the ac
31 rigid with a preselector control handlever 32 pivoted
companying drawings. Other features and advantages 4:5 about a ?xed pivot pin 33.
of the invention will appear as the description proceeds.
In order better to distinguish the movable pivot points
In the drawings:
from the ?xed pivot points on the tractor or its ?nal
FIGURE 1 illustrates diagrammatically in section an
drive casing, these pins are shown in the form of shaded
equipment raising mechanism constructed according to
discs in FIGURE 2.
the teachings of this invention;
The form of embodiment ‘of the distributor device ac~
50
FIGURE 2 is a diagrammatic sectional view showing
cording to this invention which is illustrated in FIGURES
the rear portion of a tractor of which the left-hand wheel
has been removed, with the carried equipment consisting
in this case of a plough;
FIGURE 3 is a diagrammatic section showing on a
larger scale a relief valve incorporated in the distributor
l and 3 to 6 consists of a unitary block in which are in
corporated the inlet and exhaust valves 34 and 35, respec
tively, the cock 36 adapted to connect the delivery duct
37 of a pump 38 directly to the reservoir 39 ?lled with
hydraulic ?uid such as oil, the relief valve 40 and the
‘ device of this invention;
distributor proper 41. This distributor device communi
FIGURE 4 to 6 illustrate diagrammatically three dif
cates with the reservoir 39 through a discharge duct 42
ferent positions of the distributor slide valve;
and with the cylinder 10 through a pipe line 43.
FIGURE 7 is another diagrammatic sectional view 60
The member controlled directly by the mechanical con
showing an alternate form of embodiment of the equip
trol members illustrated in the right-hand side of FIG
ment raising device of this invention;
URE 1 is the slide valve member 44 constantly urged
FIGURE 8 illustrates diagrammatically a modi?ed
against the aforesaid push-rod 18 by a spring 45.
mounting of the raising device of FIGURE 7, at the rear
The slide valve 44 is slidably mounted in the distributor
of a tractor; and
I
41 shown on a larger scale in FIGURE 4. This distrib
utor comprises around its slide valve member and from
the end adjacent to push-rod 18 three chambers 46, 47
and 48 in axial alignment. The ?rst chamber 46 is
bly of mechanical component elements illustrated in the
right-hand portion of FIGURES l and 2, which assem 70 separated from the second chamber 47 by a partition
through which an ori?ce 49 is formed, and the second
bly is adapted to act upon a single control member of
chamber 47 is separated from the third chamber 48 by
the distributor shown in the left-hand portion of FIG
URE 1, this control member being sunk more or less in
another partition in which a passage 50 is formed, this
the distributor body during the operation of the assembly.
third chamber 48 being separated in turn from a cavity
The traction rods 1 permitting the rigid mounting of
51 by'a partition formed'with a passage 52.
FIGURE 9 is a detail view showing an alternate form
of embodiment of the ‘distributor slide valve.
The device of this invention is comprised of an assem
5
3,307,455
The slide valve member 44 is a one-piece member
projecting from the distributor 41 with a cylindrical end
6
the discharge duct 42 through the intermediary of the
aforesaid exhaust valve 35. Throttling devices such as
an adjustable needle valve 83 interposed in the duct 64
ing between this cylindrical end portion 53 and the sur
connecting the cylindrical chamber 63 of cock 36 to the
rounding bore in the distributor wall is collected by a
?rst chamber 46 of distributor 41 and another adjustable
cavity 54 communicating through a passage 55 with the
needle valve 84 mounted immediately upstream of the
discharge duct 42.
exhaust valve 35 permit a proper limitation of the equip
As seen from its cylindrical end 53 the slide valve
ment raising and lowering speeds.
member 44 comprises a frustoconical valve portion 56
A throttling device 85 may also be provided in the duct
disposed in the second chamber 47 and adapted to close 10 connecting the closed chamber 72 of cook 36 to the second
the ori?ce 49, a piston~type shutter 57 disposed in the
chamber 47 of the distributor, the function of this device
plane of the third chamber 48 and adapted to close
being explained presently.
either passage 50 or passage 52, and ?nally a cam portion
Finally, another cook 86, for example a three-way cock,
58 disposed in the cavity 51 and adapted to hold the
which may be interposed in the pipe line 43 connecting
shutter 59 of exhaust valve 35 open or unseated by means 15 the raising cylinder 10 to the distributor device permits
portion 53 engaged by the push-rod 18. Any ?uid leak
of a ball 60 and a control rod 61. A passage 62 formed
of closing this line and to connect other apparatus oper
in the slide valve body connects the cavity 51 to the dis
charge duct 42. The distances between the valve shutter
56, piston shutter 57 and cam 58, on the one hand, and
between the seat of valve shutter 56 in ori?ce 49, the
edges by which passage 50 and cavity 51 open into the
ated by the hydraulic ?uid under pressure than the raising
cylinder 10 to the distributor device.
The equipment-raising device described hereinabove by
third chamber 48 and the ball 60, on the other hand are
so calculated that the communication between the ?rst,
in the linkage in the direction of the arrow shown on the
traction rod 1 of FIGURE 1 varies as a function of the
way of example operates as follows:
(1) E?ort control device.—-The tractive effort exerted
type of work to be performed by the equipment and varies
second and third chambers is established, that between
the third chamber 48 and cavity 51 is discontinued and 25 also during the Work performed by a given equipment as
a function of the changes arising inevitably in the nature
exhaust valve 35 is closed when the slide valve member
of the soil as the tractor and equipment unit is operated.
has completed its stroke to the -left, as shown in FIG
As long as the tractive effort remains below a prede
URE 4, and that the slide valve member closes the pas
termined value the spring 15 holds the arm 12 stationary
sage between the chambers, frees the passage between
against the stop 13. When this effort rises above this
the third chamber 48 and cavity 51 and the discharge
value the arm 12 moves to the left and elongates the spring
duct 42, and causes the opening of the exhaust valve 35
15 until the spring force balances the tractive effort
when it ‘attains its endmost position to the right (FIG
through the medium of the arms of lever 12 and crank
URE 6). In an intermediate position (see FIGURE 5)
shaft 4.
the slide valve member frees only the passage from the
Thus, for each value of the tractive effort which lies
?rst chamber to the second chamber. Of course, the slide 35
within the adjustment range contemplated by construc
valve member may occupy intermediate positions in which
tion, the lever 12 will occupy a position between stop 13
the different passages are more or less throttled.
and stop 14.
The cock 36 comprises a cylindrical chamber 63 con
During its movements this lever 12, through the inter
nected to the delivery duct 37, and through a duct 64
mediary of pivot pin 17, carries along the ?rst bearing
to the ?rst chamber 46 of distributor 41 and through
member 16. Thus, this bearing member 16 is caused to
a passage 65 do the discharge duct 42. Slidably ?tted
occupy different positions as a function of the variations
in the cylindrical chamber 63 is a ?rst piston 66 which
carries, aligned on one side and in this order, a valve
shutter 67 and another, smaller piston 68 sliding in a
closed cylinder 69. A duct 70 formed in the valve shutter
in the tractive effort and therefore, as a function of these
positions, to engage the push-rod 18 and to move same
more or less to the left.
Moreover, it is possible to vary the position of the
?rst bearing member 16 in relation to this lever 12 by
munication between the delivery duct 37 and the space
means of the handle 23, lever 22, stop 20 and rod 25.
formed between the second piston 68 and the bottom of
As a result, different positions of push-rod 18 can be
the closed cylinder 69. On the other side of said ?rst
piston 66 a spring 71 housed in a closed chamber 72 exerts 50 obtained for a same position of lever 12, thus permitting
the proper adjustment of presetting of the beginning of
a resilient force on the ?rst piston 66 so that the valve
the upward pulse given to the equipment-raising means in
shutter be urged against the seat-forming passage 65.
relation to the value of the tractive effort.
The closed chamber 72 communicates with the second
Thus, with the first bearing member 16 adjusted for
chamber 47 of distributor 41.
The relief valve 40 of which one portion is illustrated 55 maximum sensitivity, it will contact the push-rod 18
and cause the hydraulic ?uid pressure in the equipment
on a larger scale in FIGURE 3 comprises a piston-type 1
raising cylinder to increase when the lever 12 ceases from
shutter 73 sliding in a cylinder 74. This shutter 73 opens
hearing against the stop member 13. On the other hand,
with one of its ends into a cavity 75 communicating with
if the ?rst bearing member 16 is adjusted for minimum
the closed chamber 72 of cock 36, a sliding seat 76 open
ing likewise into this chamber, as shown. This sliding 60 sensitivity corresponding to the higher range of tractive
efforts it will be necessary that lever 12 attains a position
seat communicates with the discharge duct 42 and is
relatively remote from stop member 13 (which corre
urged by a spring 77 in the direction of shutter 73. How—
sponds to a substantial value of the tractive effort) before
ever, its stroke is limited in this direction by a shoulder
67 and the second piston 68 maintains a permanent com
78.
The other end of shutter 73 opens into a control
the ?rst bearing member 16 causes a pressure increase by
chamber 79 communicating with the aforesaid third 65 depressing the push-rod 18.
When the ?rst bearing member 16 is in its endmost
chamber 48 of distributor 41. The diameter 80 of said
position to the left (FIGURE 4) abutting against the
sliding seat 76 engageable by said shutter is smaller than
push-rod 18 and while lever 12 continues its leftward
either the diameter 81 of cylinder 74 or the diameter 82
movement, the ?rst bearing member 16 tilts due to the
of the passage in which the seat 76 is slidably ?tted
(see FIGURE 3).
Finally, the pipe line 43 connected to the raising cylin
der 10 communicates on the one hand with the second
sliding movement of rod 25 in its tube 21 and thereby
causes elongation of spring 19.
(2.) Equipment raising controL-The second bearing
member, that is, cam 26, acts upon the push-rod 18 in
chamber 47 of distributor 41 through the medium of the
conjunction with, but independently from, the ?rst bear~
inlet valve 34 permitting the ?ow of hydraulic ?uid from
this chamber to the cylinder and on the other hand with 75 ing member 16.
3,307,455
7
8
Starting from the neutral Position of the slide 44 when
the lever 32 is moved towards the right in the drawing,
the link 30 is pulled towards the left by the small lever
31 rigidly connected with the lever 32. The link 29
turns around its pivot point on the lever 8 in clockwise
ing in the cylindrical chamber 63 of valve 36 the ?uid
pressure necessary for opening this valve.
The upward movement of the equipment (see FIG
URE 4) is controlled by moving the slide valve 44 left
wards; it has been explained hereinabove that this move
direction and forces the link (28) to move towards the
left and therefore to turn the cam 26 in counter-clock
bearing member 16 transmitting the reactions of the
wise direction. This causes the displacement of the
slide 44 towards the left and the feeding of the jack.
The feeding of the jack causes the lever 8 to turn
around the pin 9 and the lever 32 being then ?xed, this
has the effect of returning the link 28 to the right, carry
ing along the cam 26 in clockwise direction. The move
ment stops when the slide 44 has returned, under the
action of the spring 45, into neutral position.
For control of descent, the procedure is the same
but the lever 32 is in this case moved towards the left.
(3) Conjugate action of the equipment-raising control
ment could be caused either by the cam 26 or by the ?rst
equipment during the work.
During its movement the slide valve 44 frees the pas
sage betWeen chambers 46, 47 and 48, while closing the
passage 52 between the third chamber 48 and cavity 51.
The moderate oil pressure prevailing in this case in the
second chamber 47 is transmitted to control chamber
79 of relief valve 40 wherein it applies the shutter 73
against its sliding seat 76.
As the return of oil to the reservoir 39 through the
sliding seat 76 is discontinued the pressure becomes sub
stantially equal to that prevailing in the closing chamber
72 and in the cylindrical chamber 63 of valve 36; in
neutral position, the ?rst bearing member 16 cannot act 20 other words, this pressure becomes equal on either side
of pistons 66 and 68. Therefore, spring 71 will seat the
upon push-rod 18 save for moving same to the left to
valve shutter 67.
its initial neutral position, that is, only for controlling
and of the stress control means.—-When cam 26 is in its
a pressure increase and therefore an upward movement
Since the ?uid cannot ?ow freely through the passage
of the equipment.
65 and since the sliding seat 76 of relief valve 40 is fully
position preselection with the stress control, whereby the
maximum working depth of the equipment is determined
in an unchanging manner by the preselection, and the
the pressures prevailing in these chambers.
When the ?rst bearing member 16 moves to the right 25 closed, this ?uid is forced into the raising cylinder by
?owing along duct 64, ?rst and second chambers 46,
from the neutral position of push-rod 18, the latter re
47 around the unseated ‘ball 34 of the inlet valve, and
mains in engagement with cam 26 and therefore no con
?nally through the pipe line 43.
trol of a downward movement below the position pre
It will be noted that the quantity of oil discharged
selected by means of the preselector control handlever 32
can take place.
30 through passage 65 is determined by the pressure dif
ferential obtaining between the cylindrical chamber 63
With this arrangement it is possible to combine the
and the closing chamber 72, irrespective of the value of
Now this
‘ pressure differential varies as a function of the throttling
stress control is effective for producing a load transfer
actions produced in the circuit downstream of valve 36.
followed by a gradual upward movement of the equip
The throttling action produced by the adjustable needle
ment immediately when the tractive effort equals or ex
ceeds a predetermined value.
valve 83 may be adjusted permanently with a view to re
duce under all circumstances the maximum feed rate of
the cylinder, the throttling action of ori?ce 49 which is
When it is desired that the position of the equipment
be determined only by the effort control device, the 40 caused by the valve shutter 56 varying on the other
hand as a function of each slide valve movement. Thus,
position preselector control handlever 32 must be so
it will be seen that when a relatively short slide valve
placed that cam 26 be positioned somewhat backwards
movement takes place as the ori?c 49 is throttled consid
in relation to the neutral position of push-rod 18.
erably the ?uid output to the cyinder will be very small,
From the intermediate position of slide valve 44 in
which the raising arm 7 is kept in a predetermined posi 45 whereas a longer slide valve stroke will practically elimi
mate the throttling action so that the feed rate of the
tion the distributor device permits of controlling either
the upward movement of the equipment by moving the
cylinder can attain its maximum value determined by the
adjustment of needle valve 83.
slide valve to the left, or the downward movement of
the equipment by moving said slide valve to the right.
The throttling device 85 is designed to permit a rapid
In the intermediate or neutral position of slide valve 44 50 pressure drop in closing chamber 72 when shutter 73
begins to move away from its sliding seat 76 in order to
(see FIGURE 5) the hydraulic ?uid is allowed to ?ow
from the ?rst chamber 46 to the second chamber 47, and
ensure a clean return of valve shutter 67 of valve 36 to its
open position.
from the third chamber 48 to the exhaust duct 42 through
cavity 51 and passages 62. Since the control chamber
The downward movement of the equipment (see FIG
79 of relief valve 40 is connected to the discharge duct
URE 6) is controlled by a movement of slide valve 44
to the right.
42 through the third chamber 48, the ?uid delivered by
pump 38 and ?owing freely into the cavity 75 of relief
When the cam 26 is moved away from the distributor
valve 40 through the circuit comprising the delivery duct
body the coil spring 45 moves the slide valve member
37, cylindrical chamber 63 of valve 36, duct 64, ?rst
44 to the right, thus holding it in contact with the cam.
and second chambers 46, 47 and throttling device 85,
As it completes its stroke (i.e. after having cut off the
unseats the shutter 73 due to the pressure exerted on the
passage between the three chamber 46, 47 and 48) the
relevant annular portion corresponding to the difference
slide valve member 44 unseats by means of its cam 58
between diameters 80 and 81 (see FIGURE 3). There
the ball 60 which unseats in turn the shutter 59 of exhaust
fore, this hydraulic ?uid may ?ow freely through the
valve 35 through the medium of the control push-rod
sliding seat 76 to the discharge duct 42 without exerting 65 61. This shutter 59 is hydraulically balanced and seated
any control pressure in the closing chamber 72 of valve
only by the spring 86 (FIGURE 1). The oil contained
36. Under these conditions, the oil delivery pressure
in the cylinder is thus discharged to the reservoir through
prevailing in the cylindrical chamber 63 of valve 36 acts
pipe line 43, needle valve 84 and discharge duct 42.
upon the ?rst piston 66 and through duct 70 upon the
Finally, one of the component elements of the dis
second piston 68 thereof, these pistons compressing the 70 tributor device, the relief valve 40‘, is also adapted to
coil spring 71 and unseating the shutter 67 to free the
operate as a pressure limiting device. The shutter 73
passage 65 through which the major portion of the oil
of this valve comprises a stop member limiting its stroke
is returned directly to the reservoir 39 through the dis
in the direction of its sliding seat 76.
charge duct 42. The throttling device 85 assists in con
When the shutter 73 under the in?uence of the pressure
junction with the adjustable needle valve 83 in establish
build up-in» chamber 79 is abutting it also bears against
3,307,455
10
its sliding seat 76 which has moved and partially com
pressed spring 77 (see FIGURE 3). If the pressure in
cavity 75, (which applies to the annular section of sliding
seat 76 corresponding to the difference existing between
the diameter 82 of the bore in which said seat is slidably
mounted and the diameter 80 engaged by the shutter on
this seat) exceeds the value corresponding to the cali
bration of spring 77, the sliding seat 76 by compressing
to a greater extent the spring 77 will move away from
also of the sliding piston type formed at one end with a
shutter adapted to engage a seat 133 through which the
duct 131 communicates with another duct 134 constantly
connected to the discharge duct 128.
At the other end of valve 132 a control chamber 135
constantly connected to chamber 123 is provided.
Chamber 121 is connected through an inlet valve 136
to a duct 137 communicating normally through a cock‘
138 with a duct 139 leading to the aforesaid pipe line
shutter 73 and open the passage leading to discharge duct 10 113. This duct 139 is also constantly communicating
42. Under these conditions, the pressure decreases im
with a duct 140 in which a needle valve 141 is inserted,
mediately in the closing chamber 72 of valve 36, due to
this duct 140 having in addition with a duct 142 con
the throttling device 85 limiting the permissible re-feeding
nected to the ‘discharge duct 128 a communication con
of said closing chamber, thus opening valve 36 and dis
trolled by an exhaust valve 143 of the balanced type
charging the oil through passage 65 to the discharge 15 which is urged to its seated position by a spring 144.
duct 42.
A modi?ed form of embodiment of the raising device
of this invention will now be described with reference to
FIGURES 7 and 9.
In this alternate form of embodiment the preselector 20
This valve 143 is controlled by means of a ball 145 en
handlever is provided with a stop member co-acting uni
directionally with the second bearing member pivoting
in the direction permitting the positive displacement of
gaged by a cam face or ramp 146 (see FIGURE 9)
formed on the sliding member 119 cf the distributor
slide valve.
On the other hand a safety valve 150 is connected
to the control chamber 129 of valve 126. This safety
valve. 150 consists of a piston-like member slidably
mounted in a bore 151 and carrying a shutter 152 adapt
this member and of the slide valve for producing the
ed to engage a seat 153 opening int-o the chamber 129.
equipment raising movement. The spring urging the' 25 This shutter 152 forms with the valve bore and the piston
slide valve in the opposite direction tends to keep the
second bearing member in contact with said stop member.
an annular chamber 154 constantly communicating with
a duct 155 which'a rotary cock 156 is adapted to either
The pivoted linkage of the preselector control system
isolate from, or connect through its inner passages 157
comprises an element co-acting undirectionally with the
with, a duct 158 connected in turn to the discharge duct
raising arm provided with a stop member, said element 30 142. On the side opposite to the shutter 152 the valve
150 is urged by a spring 159 housed in a chamber 160
being urged by said spring for engagement with this stop
having a diameter somewhat greater than that of bore
member. The stop member of the adjustment handlever
151, and the piston sliding in this bore is formed with at
is so disposed thereon that it acts as a counter-stop to
least one ?at side face 161 forming in the bore 151 a pas
said ?rst pivoting bearing member in order to adjust ac
cording to its position the setting into operation of the 35 sage permitting the communication between the annular
slide valve in the equipment raising direction when the
chamber 154 and the chamber 160 after a certain com
pression of spring 159 which corresponds to a backward
movement of shutter 152, said chamber 160 communicat
ing permanently with the duct 158 through a duct 161
?ed arrangement comprises a three-point equipment
coupling system comprising as in conventional systems 40 and the passage of cock 156.
The slide valve member 119 of the distributor has one
of this character two lateral traction rods 102 pivoted
end urged against a control push-rod 162 by one end
on the rear part of the tractor frame and raising links
of a compression spring 163 bearing against the distribu
103 connected on the other hand on the end of a raising
tor body with its other end.
arm 104 pivoted on the tractor frame structure by means
At the ends of the slide valve member a pair of cham
of a pivot pin 105.
45
bers 164 and 165 are provided which communicate re
The equipment illustrated in this case is also a plough
spectively with the discharge ducts 142 and 128, cham
pivotally connected to the rods 102 at 106 and to another
ber 164 communicating in addition through a passage 166
link 107 at a third point 108.
tractive effort exceeds a predetermined value.
As shown in FIGURE 8 the tractor 101 of this modi
formed in slide valve member 119 with an annular space
As shown in FIGURE 7, co-a-cting with the raising
167 formed between this member 119 and the surround
arm 104 is a single-acting cylinder 109 having its cylinder
ing cavity, this passage 166 being adapted to communi
body 110 rigid with the tractor and its piston 111 con
cate or not with chamber 123 according to the position
nected through a thrust rod 112 to the aforesaid arm 104.
of the piston shutter 124 of the slide valve in relation
Connected through a pipe line 113 is a hydraulic device
to the slide valve member 119.
114 for distributing ?uid under pressure from the reser
In this form of embodiment the push~rod 162 is spring
voir 115 through the medium of a pump 116 and a deliv 55
loaded and consists of'two members 1621, 1622 slidably
ery duct 117, a discharge duct 118 connecting the dis
mounted in each other with a spring 168 interposed there
tributor device 114 to the reservoir 115, as shown.
between, their relative expansion lbeing limited by a pin
This distributor device comprises a slide valve member
169. Spring 168 is tightened with a force greater than
119 slidably ?tted in the distributor body forming a plu
rality of spaced annular chambers adapted to be isolated 60 that of spring 163 in its maximum compressed position,
whereby the push-rod 162 acts norm-ally as a rigid mem
her with respect to spring 163. This push-rod 162 car
ries a pin 170 on which are pivoted intermediate their
ends the second pivoting bearing member and the ?rst
of a piston shutter 124.
The pump delivery duct 117 is connected to a duct 125 65 pivoting bearing member, in the form of a lever 172, of
a tractive effort control system.
of the distributor device which communicates permanent
The second pivoting bearing member 171 is an integral
ly with the aforesaid chamber 120, this duct 125 having
part of a linkage interposed between an adjustable pre
inserted therein a valve 126 having its valve shutter adapt-v
selector handlever 173 and the raising arm 104. The
ed to engage a seat 127 to control the ?uid flow to another
duct 128 connected to the discharge duct 118. The 70 preselector handlever 173 is provided with a stop 174
co-acting unidirectionally with one end of the other
valve shutter of valve 126 is in the form of a sliding piston
‘bearing member 171 having its opposite end connected
having a closing control chamber 129 containing a coil
spring 130 and connected to the aforesaid chamber 121
to a link 175 pivoted on the other hand intermediate the
by means of a duct 131 in which a relief valve or pilot
ends of lever 176, this lever 176 having one end pivoted
valve 132 of valve 126 is inserted. This valve 132 is 75 on a ?xed pin 177 of the tractor and the ‘other end co
from one another by means of slide~valve shutters, no
tably chambers 120, 121 separable by a valve shutter 122
and chamber 123 separable from chamber 121 by means
3,307,455
11
12
acting unidirectionally with a stop member 178 carried
by said raising arm 104. This linkage is so designed that
the aforesaid spring 163 of slide valve 119 constantly
urges through push-rod 162 the second bearing member
urges said member to its closed position against seat
171 and lever 176 in contact with stop members 174
and 178.
'
The ?rst bearing member 172 is an integral part of
a linkage interposed between an effort-control adjustment
lever 180 and the equipment coupling system comprising
133, this pressure preponderance being due notably to
the presence of a throttled passage 192 formed in the
duct 131 and to the preliminary opening of the seat
133 of this valve.
Under these conditions the pressure built up in the
closing chamber 129 of valve 126 attains a value tend
ing to equal the oil delivery pressure toward the reser
voir through this valve, whereby the shutter thereof will
resilient means responsive to the tractive effort, which 10 then be urged to its closed position by the spring 130.
Under these conditions the oil pressure rises in the cir
means in this example consists of a compression spring
cuit involved and the cylinder 109 is then fed through
181. This spring 181 is interposed between the tractor
the inlet valve 136. This produces an upward move
frame structure and a ‘guide push-member 182 responsive
ment of arm 104 and therefore of the equipment, simul
to the action of a lever 183 forming an integral part of
taneously with a movement to the right (as seen in the
a crankshaft pivoted on a ?xed pivot pin 184 and pro
drawing) of the stop member 178, so that the linkage
vided, on the other hand, with crankpins 185 on which
176, 175, 171, push-rod 162 and slide valve member
the aforesaid traction rods 102 are pivoted as at 186.
119 move back to the right as seen in the drawing until
Lever 183 bears against the tractor frame structure as il
they are stopped in a stable position when the slide valve
lustrated in FIGURE 7 for a given degree of prestress of
member 119 has resumed its neutral position.
spring 181 which is determined as a function of the range
of tractive efforts to which the spring is required to react
In fact, it will be noted that as slide valve member
119 resumes its neutral position the piston shutter 124
by deformation.
The adjustment lever 180 is formed with a stop mem
thereof simultaneously separates chambers 121 and 123
ber 187 adapted to engage unidirectionally one end
from each other and restores the communication between
of the ?rst pivoting bearing member 172 of which the 25 this chamber 123 and control chamber 135, on the one
other end is connected to a link 188 which, by means
hand, and reservoir 115, on the other hand, thus caus
ing the opening of seat 133 of pilot valve 132 and a
of a bell-crank lever 189 pivoted on pin 177, co-acts
with another link 190 connected in turn to the lever 183
pressure drop in closing chamber 129 of valve 126,
whereby the oil pressure exerted against this valve 126
of said crankshaft.
becomes again preponderant in relation to the action of
The control handlevers 173 and 180 are mounted on
spring 130 and causes the opening of seat 127 to restore
a common ?xed pin 191 and can be locked in relation
thereto in any desired angular position by means of
the communication between the pump and the reservoir.
. During this return movement of the slide valve mem
any known and convenient device designed for control
ber to its intermediate or neutral position the throttled
means of this character, this locking system being no
part of the present invention.
passage 192 permits a rapid pressure drop in closing
It will be noted in the drawings that the ?xed pivot
pins carried by the tractor are shown in the form of
chamber 129 immediately as the seat 133 is re-opened,
thus causing a clean return of valve shutter 126 to its
open position.
shaded discs in order to set them in sharper contrast
To obtain a downward movement of arm 104 the
to the other pivot pins.
The above-described alternate form of embodiment 40 preselector handlever 173 must be moved in the direction
of the hydraulic equipment raising control device of this
of the arrow D. In this case the spring 163 urges the
slide valve member 119 and push-rod 162 to the right,
invention which is illustrated in FIGURES 7 to 9 op
as seen in the ?gures, together with the second pivoting
crates substantially in the same manner as the ?rst form
bearing member 171 due to the clearing of stop member
of embodiment described hereinabove in connection with
FIGURES l to 6 of the drawings, except for minor de
174 in relation thereto, and in addition the movement of
slide valve member 119, while maintaining the circuit
tails.
It will be seen ?rstly that the preselector control sys- ‘
in the by-pass condition, will open by means of the cam
face or ramp 146 the exhaust valve 143 to vent the cyl
tem implies that to each selected angular position of
inder 109. This venting of cylinder 109 takes place
the preselector handlever 173 there corresponds a pre
determined angular position of the equipment raising 50 through needle valve 141, whereby the rate of down
arm 104 in which as both elements 171 and 176 bear
against stop elements 174 and 178, the distributor slide
ward movement of the equipment can be adjusted at
will. This involves a downward movement, toward the
left-hand side of the ?gures, of stop member 178, where
by the linkage system comprising 176, 175, 171, push
sition which is the position shown in FIGURE 7.
In this position, the oil delivered by pump 116 into 55 rod 162 and slide valve 119 resumes a stable position
corresponding to the intermediate or neutral position
the delivery duct 125 is returned to the reservoir through
of slide valve member 119 in which position this mem
the‘valv'e 126, the shutter of this valve being unseated
ber 119 permits the re-closing of exhaust valve 143.
by the fact that the oil delivery pressure exceeds the
If it is required to raise the equipment, the preselector
‘force of spring 130‘since no pressure exists in the closing
chamber 129; stress may be laid on the fact that in
control handlever 173 may be moved in the direction M
1n such a manner that it involves a movement of pin 170
spite of a possible ?ow of ?uid from chamber 120‘ to
of slide valve member 119 which is greater than the per
chamber 121 in the neutral position of the slide valve
missible stroke of this member 119 toward the left-hand
the duct 131 is then connected to the reservoir through
side of the ?gures, for when the slide valve member abuts
the seat of pilot valve element 132 of valve 126.
To produce the upward movement of arm 104 and 65 in the distributor body while compressing home the spring
163, the spring-loaded member 162 retracts to permit
therefore of the equipment carried thereby, the operator
a complementary movement of pin 170.
moves the preselector handlever 173 in the direction of
Of course the push-rod 162 could also consist of a rigid
the arrow M. In this case the push-rod 162 moves the
member but in this case the operation, in the case of
slide valve member 119 to the left, thus disposing the
raising movements of relatively great amplitude, should
valve shutter 122 and piston shutter 124 of the slide
accompany the preselector handlever 173 to the desired
valve in such positions that the annular chambers 120,
position as the equipment is actually raised.
121 and 123 communicate with one another, chamber
It will be noted that the interaction between this pre
123 being isolated ‘from the reservoir 115. As a re
selector control and the effort control means produces
sult, the shutter member of pilot valve 132 is responsive
to a preponderant pressure in control chamber 135 which 75 through the pivot pin 170 a displacement of the ?rst pivot
valve member 119 is in its intermediate or neutral po
3,307,455
13
14
ing bearing member 172 of this last-named control means
of which the movement takes place with-out any inter
It will be noted that if under these conditions the trac
tive effort continues to decrease, the downward movement
of the equipment can be limited when the aforementioned
‘ ference whatsoever in case of equipment raising move
ment and must be assured, to permit the above-described
play given to the preselector control has been taken up,
operation in case of downward movement, by the provi
for this control will then become operative to return the
sion of a minimum play e between the stop member 187
slide valve and the control elements associated therewith
of adjustment handlever 180 and the element 172 of the
to their initial neutral positions shown in the drawing.
effort control, this play e being such as to permit the
It is clear that this dual-control device permits of com
movement of pin 170 to the extent necessary for actuat
bining the preselector control means with the effort con
ing the exhaust valve 143.
10 trol means, so that the maximum working depth of the
The above-described tractive effort control device oper
equipment be determined by the preselector control means
ates as follows:
whereas the effort control means are effective to limit
The effort required for pulling the equipment or tool
the tractive effort to a predetermined maximum value.
during the work (for example the ploughing of a soil),
Of course, the maximum working depth may be select
which corresponds to the resistant effort exerted in the 15 ed by means of the preselector control and set to such
direction of the arrow F on the traction rods 102, varies
as a function of vthe type of work performed and during
a same type of work according to changes intervening in
a value that the effort control becomes preponderant dur
ing the operation, if desired.
More particularly, it will be noted that the tractive
the quality of the soil.
effort value above which the effort control becomes opera
As long as this effort F transmitted to the spring 181 20 tive is simply determined by the position of stop member
in the manner described hereinabove exerts on ‘this spring
187 and therefore of the adjustment handlever 180 locat~
a force inferior to the prestress force of said spring, the
ed within easy reach of the operator. The displacement
lever 183 remains in abutment against the frame struc
of the adjustment handlever 180 in the direction P (FIG
ture of the tractor and the effort control system is inopera
URE 7) will cause notably the compression stroke of
tive in relation to the preselector control by which the 25 spring 181 to increase, thus incrementing the effort value
desired working depth of the equipment was preset.
at which the effort control becomes operative, whereby
When this effort F increases until the spring 181 is
this adjustment handlever 180 enables the operator to
compressed to a condition of equilibrium depending on
select the desired sensitivity of the effort control as a
the effort involved, the lever 183 is raised and through
function of the type of work to be or being performed.
the elements 190, 189 and 188 the ?rst pivoting bearing 30
On the other hand, any overload in the feed circuit of
member 172 is caused to move angularly about the pivot
cylinder 109 is safety avoided due to the provision of the
pin 170 directed toward the abutment 187 of adjustment
safety or relief valve 150 in the distributor body, this
valve co-acting with the valve 126 under the following
handlever 180.
From the moment the ?rst pivoting bearing member
conditions:
172 engages the stop member 187, the movement of this 35
When the control lever of- cock 156 is so positioned
member 172. is changed to a pivoting movement, during
that chamber 154 of valve 150 is connected through a
which said stop'member 187 serves as a fulcrum, thus
passage thereof with the discharge duct 142, the maximum
causing the translation of pivot pin 170 of push-rod 162
value of the circuit pressure is that above which the shut
to the left, as seen in the ?gures,‘ and moving consequently
ter 152 is lifted off its seat 153, thus connecting the clos
the slide valve member 119 in the direction to release
ing chamber 129 of valve 126 to the exhaust and causing
the hydraulic feed of cylinder 109 and cause the upward
the immediate opening of the seat 127 of this valve so as
movement of the tractor equipment under the conditions
to connect the pump with the reservoir.
'already set forth. The thus initiated raising movement
When cock 156 is turned to close the passage 155, the
of the equipment causes the effort vF exerted on the trac
pressure prevailing then in the circuit is adapted, as a
ti-on rods 102 to decrease, whereby the spring 181 is some
45 consequence of leakages at the level of shutter 152 and
what allowed to expand. When as a consequence of the
foregoing the linkage 183, 190, 189, 188 and 172 resumes
its preceding position in which the ?rst bearing member
172 engaged the stop member 187, the pivot pin 170 has
'
Iresumed the position corresponding to the neutral position 50
seat 153, to become effective in the chamber 154 of valve
150, so that for a given pressure then applied to the entire
surface of the sliding piston constituted by valve 150 the
latter compresses the spring 159 until the ?at face 161 of
the piston, by receding, opens the communication between
of slide valve member 119 in which the distributor is
chambers 154 and 160. As this last-named chamber 160
again in its by-pass condition, as already explained.
is constantly communicating with the reservoir, as already
explained the closing chamber 129 of valve 126 is exhaust
ed, whereby the maximum pressure is limited by the
Thus, the overstepping of a predetermined tractive effort
‘involved automatically the application of a raising im
pulse to the equipment which tends to regularize the nec
essary tractor hauling effort.
It may also be noted that when the slide valve mem
ber 119-has resumed its neutral position, with the ?rst
pivoting bearing member 172 engaging the stop member
55 opening of this valve.
In this case the safety pressure
may be selected to have a lower value than in the preced
ing case, the use of two safety pressure values depending
if desired on speci?c working conditions, and may notably
be useful in case the distributor were used for feeding
187 under the conditions set forth hereinabove, the link 60 load other or auxiliary apparatus outside the equipment
raising cylinder 109, which are adapted to be connected
age system of the preselector control assembly has a cer
to the distributor through the duct 1391 and fed by means
tain play in relation to the stop members 174, 178 due
of the three-way cock 138 so as to isolate the raising cylin
to the equipment-raising impulse which has just been
der 109 in this case.
controlled by the effort control system.
Although the present invention has been described not
If in this case the tractive effort dropped below the 65
value having caused the ?rst bearing member 172 to con
ably in conjunction with two preferred embodiments, it
is to be understood that modi?cations and variations may
tact stop member 187, spring 181 will expand further and
' be resorted to without departing from the spirit and scope
slide valve member 119 will then be caused to move
of the invention, as those skilled in the art will readily
to the right, as seen in the ?gures, in the direction to
operate the exhaust valve 143 of the cylinder, as per 70 understand. Such modi?cations and variations are con~
sidered to be within the purview and scope of the inven
mitted by the aforementioned play stored by the preselec
tion and appended claims.
tor control. Under these conditions, the equipment will
What is claimed is:
be lowered to a greater working depth, thus tending to
1. Hydraulic equipment-raising and tractive-effort con
‘ compensate the aforesaid reduction in tractive effort and
. therefore to regularize this reduction.
trol device for farming tractors of the carried equipment
3,307,455
15
type, comprising a single-acting raising cylinder co-acting
with at least one equipment lifting arm, an equipment
coupling system to which said lifting arm is connected and
comprising traction links, a source of hydraulic ?uid under
pressure, a hydraulic distributor device comprising a mov
able slide valve member for distributing the hydraulic
?uid delivered from said source of ?uid under pressure
either, in a ?rst position of said slide valve member, to
said raising cylinder through an inlet valve, or, in a second
position of said slide valve member toward which said
valve member is urged by a spring, from said raising
cylinder through an exhaust valve to a discharge duct
connected to the reservoir feeding said source, or, further
15
which said valve member is urged by a spring, from said
raising cylinder through an exhaust valve to a discharge
duct connected to the'reservoir feeding said source, or,
furthermore, in an intermediate position of said'slide
valve member, directly to said discharge duct, it being
understood that other intermediate positions and actions
of said slide valve member are permitted, a preselector
control comprising a handlever for preselecting the de
sired position of said lifting arm and a linkage system
10 interconnecting said preselector handlever, said slide valve
member and said lifting arm, an effort. control sys
tem coacting with said slide valve member and connected
to said coupling system incorporating resilient means‘ re
sponsive to the tractive effort above a predetermined
more, in an intermediate position of said slide valve mem
value of said effort, said effortcontrol system comprising
a first pivoting bearing member so designed and mounted
that other intermediate positions and actions of said
that said coupling system is capable, through the medium
slide valve member are permitted, a preselector control
of said bearing member, of exerting. a certain force of
comprising a handlever for preselecting the desired posi
said slide valve member in the direction of said ?rst
tion of said lifting arm and a linkage system intercon
necting said preselector handlever, said slide valve mem 20, position thereof and of which the permissible movement
in the direction of said last named force is limited by an
ber and said lifting arm, an effort control system co-act
adjustable stop provided on an adjustment handlever,
ing with said slide valve member and connected to said
ber, directly to said discharge duct, it being understood
coupling system incorporating resilient means responsive
said linkage system comprising a second pivoting bearing
to the tractive effort above a predetermined value of said
member also adapted to act upon said-slide valve mem
ber while the connections between said ?rst pivoting bear
effort, said effort control system comprising a ?rst pivoting
bearing member a-buttingly engaged with said slide valve
ing member and said coupling system, on the one hand,
and between said second pivoting bearing member, said
member and so designed and mounted that said ‘coupling
system is capable, through the medium of said bearing
member, of exerting a certain force on said slide valve
member in the direction of said ?rst position thereof and
of which the permissible movement in the direction of
said last-named force is limited by an adjustable stop
provided on an adjustment handlever, said linkage system
lifting arm and said preselector handlever, on the other
hand, are so ‘designed and arranged that a tractive effort
exerted on said coupling system and of ‘a value sufficient
to overcome the force of said resilient means, the displace
ment of said preselector handlever in one direction
as well as the lowering of said lifting arm be capable of
comprising a second pivoting bearing member abuttingly
causing the displacement of said slide valve member in
the direction of said ?rst position, and that a reduction
in the tractive effort which causes the effort exerted by
engaged with said slide valve member and also adapted to
act ‘upon said slide valve member while the connections
between said ?rst pivoting bearing member and said cou
said resilient means to become preponderant as well as a
pling system, on the one hand, and between said second
displacement of said preselector handlever in the opposite
pivoting bearing member, said lifting arm and said pre
direction, a displacement of said adjustment hand
selector‘ handlever, on the other hand, are so designed and
lever in the direction to enable its adjustable stop to
exert a pressure on the ?rst pivoting bearing member and
an upward movement of said lifting arm be capable of
‘ causing the displacement of said slide valve member in
arranged that atractive effort exerted on said coupling
system and of a value suf?cient to overcome the force of
said resilient means, the displacement of said preselector
the direction of said second position, characterizedin that
lifting arm be capable of causing the displacement of said 45 said ?rst bearing member is a lever having one end
slide valve member in the direction of said ?rst position,
so disposed as to be capable of exerting upon one of
handlever in one direction as well as the lowering of said
and that a reduction in the tractive effort which causes
the effort exerted by said resilient means to become pre
ponderant as well as a displacement of said preselector
handlever in the opposite direction, a displacement of said
adjustment handlever in the direction to enable its adjust
able stop to exert a pressure on the ?rst pivoting bearing
member and an upward movement of said lifting arm be
the ends of said slide valve member an effort in the axial
direction of said slide valve member, the other end of
said lever being subjected to the action ofa spring so
that said ?rst end may exert a force upon said slide
valve member in the direction of said ?rst position of
said slide valve member.
5. Hydraulic equipment raising device as set forth in
capable of causing the displacement of said slide valve
claim 4, characterized in that said second bearing mem~
member in the direction of said second position.
55 ber consists of a cam.
2. Hydraulic equipment raising device as set forth in
6. Hydraulic equipment raising device as set forth in
claim 1, characterized in that said second bearing member
claim 5, characterized in that the movable member of
consists of a cam.
said hydraulic cylinder bears against one arm of a con
3. Hydraulic equipment raising device as set forth in
trol lever solid with the lifting arm, said coupling system
claim 1, characterized in that said pivoting bearing mem 60 comprising a first link having one end pivoted on said
bers act upon said slide valve member through the medium
second bearing member and the other end pivoted on one
of a push-rod guided in the body of said distributor de
point of another link pivoted in turn'by means of a third
vice.
4. Hydraulic equipment-raising and tractive-effort con
trol device for farming tractors of the carried equipment 65
type, comprising a single acting raising cylinder coacting
link on a lever‘ arm rigid with said preselector control
handlever.
'
7. Hydraulic equipment raising device as set forth in
claim 4, characterized in that the movable member of
with at least one equipment lifting arm, an equipment
said hydraulic cylinder bears against one arm of'a con
coupling system to which said lifting arm is connected
trol lever solid with the lifting arm, said coupling sys
and comprising traction links, a source of hydraulic ?uid
tem comprising a ?rst link having one end pivoted on
under pressure, a hydraulic distributor device comprising 70 said second bearing member and the other end pivoted
a movable slide valve member for distributing the hy
on one point of another link pivoted in turn by means of
draulic ?uid delivered from said source of ?uid under
a third link on‘ a lever arm rigid with said preselector
pressure either, in a ?rst position of said slide valve mem
control handlever.
8. Hydraulic equipment-raising and tractive-effort con
ber, to said raising cylinder through an inlet valve, or,
trol device for farming tractors of the carried equipment
in a second position of said slide valve member toward
3,307,455
17
18
type, comprising a single acting raising cylinder coacting
duct connected to the reservoir feeding said source, or,
with a least one equipment lifting arm, an equipment
coupling system to which said lifting arm is connected
and comprising traction links, a source of hydraulic ?uid
under pressure, a hydraulic distributor device comprising
valve member, directly to said discharge duct, it being
furthermore, in an intermediate position of said slide
understood that other intermediate positions and actions
of said slide valve member are permitted, a preselector
a movable slide valve member for distributing the hydrau
lic ?uid delivered from said source of ?uid under pres
sure either, in a ?rst position of said slide valve mem
control comprising a handlever for preselecting the de
sired position of said lifting arm and a linkage system
interconnecting said preselector handlever, said slide
ber, to said raising cylinder through an inlet valve, or,
valve member and said lifting arm, an effort control sys—
in a second position of said slide valve member toward 10 tem co-acting with said slide valve member and con
which said valve member is urged by a spring, from said
raising cylinder through an exhaust valve to a discharge
duct connected to the reservoir feeding said source, or,
furthermore, in an intermediate position of said slide
valve member, directly to said discharge duct, it being
understood that other intermediate positions and actions
nected to said coupling system incorporating resilient
means responsive to the tractive effort above a predeter
mined value of said effort, said effort control system com
prising a ?rst pivoting bearing member so designed and
15
mounted that said coupling system is capable, through
of said slide valve member are permitted, a preselector
the medium of said bearing member, of exerting a cer
tain force on said slide valve member in the direction of
control comprising a handlever for preselecting the desired
position of said lifting arm and a linkage system inter
said first position thereof and of which the permissible
movement in the direction of said last named force is
connecting said preselector handlever, said slide valve 20 limited by an adjustable stop provided on an adjustment
member and said lifting arm, an effort control system
handlever, said linkage system comprising a second pivot
coacting with said slide valve member and connected to
ing bearing member also adapted to act upon said slide
said coupling system incorporating resilient means re
valve member while the connections between said ?rst
sponsive to the tractive effort above a predetermined value
pivoting bearing member and said coupling system, on the
of said effort, said effort control system comprising a 25 one hand, and between said second pivoting bearing mem
?rst pivoting bearing member so designed and mounted
ber, said lifting arm and said preselector handlever, on
that said coupling system is capable, through the medium
the other hand, are so designed and arranged that a trac
of said bearing member, of exerting a certain force on
tive effort exerted on said coupling system and of a value
said slide valve member in the direction of said ?rst
su?‘icient to overcome the force of said resilient means,
position thereof and of which the permissible movement 30 the displacement of said preselector handlever in one
in the direction of said last named force is limited by an
direction as well as the lowering of said lifting arm be
adjustable stop provided on an adjustment handlever,
capable of causing the displacement of said slide valve
said linkage system comprising a second pivoting bearing
member in the direction of said ?rst position, andv that
member also adapted to act 'upon said slide valve member
a reduction in the tractive effort which causes the effort
while the connections between said ?rst pivoting bear 35 exerted by said resilient means to become preponderant
ing member and said coupling system, on the one hand,
as well as a displacement of said preselector handlever
and between said second pivoting bearing member, said
in the opposite direction, a displacement of said adjust
lifting arm and said preselector handlever, on the other
hand, are so designed and arranged that a tractive effort
exerted on said coupling system and of a value su?‘icient
to overcome the force of said resilient means, the dis
placement of said preselector handlever in one direction
as well as the lowering of said lifting arm be capable of
causing the displacement of said slide valve member in
ment handlever in the direction to enable its adjustable
stop to exert a pressure on the ?rst pivoting bearing mem
ber and an upward movement of said lifting arm be
capable of causing the displacement of said slide valve
member in the direction of said second position, said sec
ond bearing member consisting of a 'cam, characterized
in that the movable member of said hydraulic cylinder
the direction of said ?rst position, and that a reduction 45 bears against one arm of a control lever solid with the
in the tractive effort which causes the effort exerted by
lifting arm, said coupling system comprising a ?rst link
said resilient means to become preponderant as well as
having one end pivoted on said second bearing member
a displacement of said preselector handlever in the op
and the other end pivoted on one point of another link
posite direction, a displacement of said adjustment hand
lever in the direction to enable its adjustable stop to exert
a pressure on the ?rst pivoting bearing member and an
upward movement of said lifting arm be capable of caus—
ing the displacement of said slide valve member in the
direction of said second position, characterized in that the
pivoted in turn by means of a third link on a lever arm
rigid with said preselector control handlever.
10. Hydraulic equipment-raising and tractive-effort
control device for farming tractors of the carried equip
ment type, comprising a single acting raising cylinder
coacting with at least one equipment lifting arm, an
movable member of said hydraulic cylinder bears against 55 equipment coupling system to which said lifting arm is
one arm of a control lever solid with the lifting arm, said
connected and comprising traction links, a source of hy
draulic ?uid under pressure, a hydraulicdistributor de
vice comprising a movable slide valve member for dis
tributing the hydraulic ?uid delivered from said source
by means of a third link on a lever arm rigid with said 60 of ?uid under pressure either, in a ?rst position of said
coupling system comprising a ?rst link having one end
pivoted on said second bearing member and the other
end pivoted on one point of another link pivoted in turn
preselector control handlever.
slide valve member, to said raising cylinder through an
9. Hydraulic equipment-raising and tractive-effort con
trol device for farming tractors of the carried equipment
inlet valve, or, in a second position of said slide valve
member toward which said valve member is urged by a
type, comprising a single acting raising cylinder coating
spring, from said raising cylinder through an exhaust
with at least one equipment lifting arm, an equipment 65 valve to a discharge duct connected to the reservoir feed
coupling system to which said lifting arm is connected and
ing said source, or, furthermore, in an intermediate posi
comprising traction links, a source of hydraulic ?uid
tion of said slide valve member, directly to said discharge
under pressure, a hydraulic distributor device comprising
duct, it being understood that other intermediate posi
a movable slide valve member for distributing the hy
tions and actions of said slide valve member are per
draulic ?uid delivered from said source of ?uid under 70 mitted, a preselector control comprising a handlever for
pressure either, in a ?rst position of said slide valve mem
preselecting the desired position of said lifting arm and
ber, to said raising cylinder through an inlet valve, or,
a linkage system interconnecting said preselector hand
in a second position of said slide valve member toward
which said valve member is urged by a spring, from said
lever, said slide valve member and said lifting arm, an
effort control system coacting with said slide valve mem
raising cylinder through an exhaust valve to a discharge 75 ber and connected to said coupling system incorporating
3,307,455
19
resilient means responsive to the tractive effort above a
chamber containing a compression spring urging said pis
predetermined value of said effort, said effort control sys
ton in the direction to close said valve, and an opening
chamber connected to said source of hydraulic ?uid under
pressure and in which the ?uid pressure urges said piston
in the valve opening direction, a controlled relief valve
of which a piston-forming shutter opens with one end
tem comprising a ?rst pivoting bearing member so de
signed and mounted that said coupling system is capable,
through the medium of said bearing member, of exerting
a certain force on said slide valve member in the direc
tion of said ?rst position thereof and of which the per
missible movement in the direction of said last named
force is limited by an adjustable stop provided on an
into a cavity into which opens likewise a valve seat com
municating with the discharge duct and with the opposite
end into a control chamber, a distributor comprising
adjustment handlever, said linkage system comprising a 10 about said slide valve member a ?rst chamber communi
cating with said source of hydraulic ?uid under pressure,
second pivoting bearing member also adapted to act upon
said slide valve member while the connections between
a second chamber communicating with said equipment
said ?rst pivoting bearing member and said coupling sys
raising cylinder through the medium of said inlet valve,
tem, on the one hand, and between said second pivoting
with said closing chamber of said valve and with the cav
bearing member, said lifting arm and said preselector 15 ity of said relief valve, a third chamber communicating
with said control chamber and with said discharge duct,
handlever, on the other hand, are so designed and
said ?rst, second and third chambers being separated
arranged that a tractive effort exerted on said coupling
by a ?rst partition disposed between said ?rst and second
system and of a value sufficient to overcome the force
chambers and by a second partition disposed between said
of said resilient means, the displacement of said pre
selector handlever in one direction as well as the lowering 20 second and third chambers, said slide valve member com
of said lifting arm be capable of causing the displace
ment of said slide valve member in the direction of said
?rst position, and that a reduction in the tractive effort
which causes the effort exerted by said resilient means to
become preponderant as well as a displacement of said 25
preselector handlever in the opposite direction, a displace
ment of said adjustment handlever in the direction to
enable its adjustable stop to exert a pressure on the ?rst
pivoting bearing member and an upward movement of
prising a valve-type shutter disposed in said second cham
ber and adapted to close an ori?ce formed in said ?rst
partition and connected through an axial rod to a piston
type shutter disposed at the level of said third chamber
and adapted to close either a passage formed in said sec
ond partition or another passage leading to said discharge
duct, the space left between the seat of said valve-shutter
and the edge of said passage leading into said third cham
ber, on the one hand, and the distance between said shut
said lifting arm be capable of causing the displacement 30 ters, on the other hand, being such that in its ?rst position
said slide valve member frees the passage between said
of said slide valve member in the direction of said second
three chambers and that in its second position it prevents
position, characterized in that said ?rst pivoting bearing
the communication between said chambers and that in the
member and said second pivoting bearing member are
intermediate position it frees only the passage between
pivoted at their fulcrums on a common pivot pin control
said ?rst chamber to said second chamber while the duct
ling the displacement of said slide valve member of said
connecting said equipment raising cylinder to said inlet
distributor device, said preselector handlever being pro
valve communicates with said discharge duct through said
vided with stop means co-acting unidirectionally with said
exhaust valve the opening of which is controlled mechan
second pivoting bearing member in the direction to per
ically by said slide valve member when the latter is moved
mit the positive displacement of said second pivoting
to its second position.
bearing member and said slide valve member to obtain
13-. Hydraulic equipment-raising device as set forth in
a lifting, said spring which urges said slide valve member
claim 12, wherein devices for reducing the cross-sectional
in the opposite direction tending to keep said second piv
area are provided in the duct connecting said second
oting bearing member in contact with said stop member,
chamber to said cavity of said relief valve, in the duct
said linkage system of said preselector control comprising
connecting said raising cylinder to said exhaust valve, and
a member co~acting unidirectionally with said lifting arm
possibly in the duct connecting said ?rst chamber to said
formed with a stop against which said last-named mem
source of ?uid under pressure.
ber is urged by said spring, said stop member of said
14. Hydraulic equipment-raising and tractive-effort
adjustment handlever being so disposed thereon that it
control device for farming tractors of the carried equip
acts as a counterbearing stop means to said ?rst pivoting
bearing member in order to adjust as a function of its 50 ment type, comprising a single acting raising cylinder
coacting with at least one equipment lifting arm, an
position the operation of said slide valve member in the
equipment coupling system to which said lifting arm is
equipment-raising direction from a predetermined value
connected and comprising traction links, a source of hy
of the tractive effort transmitted from the equipment.
draulic ?uid under pressure, a hydraulic distributor de
11. Hydraulic equipment-raising device as set forth in
vice comprising a movable slide valve member for dis
claim 10, characterized in that said movable member of
tributing the hydraulic ?uid delivered from said source
said hydraulic cylinder bears against one of the arms of
of ?uid under pressure either, in a ?rst position of said
a control lever solid with said lifting arm, the member
slide valve member, to said raising cylinder through an
which co-acts unidirectionally with said lifting arm con
inlet valve, or, in a second position of said slide valve
sisting of an inter-resistant lever or a lever of the second
member toward which said valve member is urged by a
order of which the free end is caused to engage said stop
spring, from said raising cylinder through an exhaust
member disposed on said other arm of said control lever,
valve to a discharge duct connected to the reservoir feed
while said second pivoting bearing member consists of a
lever having on one side of its fulcrum an arm kept in
ing said source, or, furthermore, in an intermediate posi
tion of said slide valve member, directly to said discharge
contact with said stop member of said preselector hand
lever and on the other side of said fulcrum another arm 65 duct, it being understood that other intermediate posi
tions and actions of said slide valve member are per_
connected through a link to the point of application of
mitted, a preselector control comprising a handlever for
the resistant effort of said inter-resistant lever or lever of
preselecting the desired position of said lifting arm and
the second order.
a linkage system interconnecting said preselector hand
12. Hydraulic equipment raising device as set forth in
claim 10, characterized in that said distributor device 70 lever, said slide valve member and said lifting arm, an
effort control system coacting with said slide valve mem
comprises the following component element: a valve
ber and connected to said coupling system incorporating
adapted to connect said source of hydraulic ?uid under
resilient means responsive to the tractive effort above a
pressure directly to said reservoir feeding said source,
predetermined value of said effort, said effort control sys
said valve being controlled by a double-acting cylinder
having its inner space divided by a piston into a closing 75 tem comprising a ?rst pivoting bearing member so de-A
3,307,455
21
signed {and mounted that said coupling system is capable,
through the medium of said bearing member, of exerting
22
enable its adjustable stop to exert a pressure on the ?rst
pivoting bearing member and an upward movement of
a certain force on said slide valve member in the direc
said lifting arm be capable of causing the displacement
tion of said ?rst position thereof and of which the per
of said slide valve member in the direction of said second
position, characterized in that said coupling system is
missible movement in the direction of said last named
force is limited by an adjustable stop provided on an
adjustment handlever, said linkage system comprising a
adapted to exert a force on said slide valve member
through a traction rod pivoted on a crankpin of a crank
shaft movable about an axis ?xed on said tractor, said
crankshaft being solid with a one~arm lever retained by
second pivoting bearing member also adapted to act upon
said slide valve member while the connections between
said ?rst pivoting bearing member and said coupling sys 10 a spring acting against the force to which it is subjected
tem, on the one hand, and between said second pivoting
by the equipment during the work, said one-arm lever
bearing member, said lifting arm and said preselector
being connected through said effort control system to said
handlever, on the other hand, are so designed and
?rst bearing member.
arranged that a tractive effort exerted on said coupling
system and of a value sufficient to overcome the force 15
References Cited by the Examiner
of said resilient means, the displacement of said pre
UNITED STATES PATENTS
selector handlever in one direction as well as the lowering
of said lifting arm be capable of causing the displace
ment of said slide valve member in the direction of said
?rst position, and that a reduction in the tractive effort 20
which causes the effort exerted by said resilient means to
become preponderant as well as a displacement of said
preselector handlever in the opposite direction, a displace
ment of said adjustment handlever in the direction to
2,799,251
2,970,653
7/1951
2/1961
Newgen ___________ __ 91-367
Hershman _________ __ 91-—367
MARTIN P. SCHWADRON, Primary Examiner.
SAMUEL LEVINE, Examiner.
P. E. MASLOUSKY, Assistant Examiner.