US2109668A - Hydraulic lift mechanism for tractors - Google Patents

Description

March 1 1938.

E. A. JOHNSTON ET AL HYDRAULIC LIFT MECHANISM FOR TRACTORS Filed April 6, 1937 v 4 Sheets-Sheet l H mm r my O a. gm q 8 Q WM Q m /1 h Q a ma w j g S QM Rww March 1, 1938. E. A. JOHNSTON ET AL 2,109,658

I HYDRAULIC LIFT MECHANISM FOR TRAC'IORS I Filed April 6, 1957 4 Sheets-Sheet 2 lnvenior EdwaFaA. f0/2726Z07z fllexus GLzLndgren.

March 1, 1938. E. A. JOHNSTON ET AL HYDRAULIC LIFT MECHANISM FOR TRACT ORS Filed April 6, 1957' 4 Sheets-sheet;

Invento'r EdwardlJb/zns i072 fllezuslm dgren 'March 1, 1938. E. A JOHNSTON 'ET AL I 2,109,633

HYDRAULIC LIFT MECHANISM FOR TRACTORS Fil ed A rii a, 195'! I 4S heets-vSheet 4 Edwarmhmt'on fllex usdLz'rzcggrer&

Patented 1,' 1938 maaumo LIFT MECHANISM roa I raao'roas Edward A. Johnston and Alexus c. Lindgren, omcago, Ill., assignors to International Harvester Company, a corporation of New-Jersey Application April 6, 1931, Serial No. 135,304 7 (01. 97-50) This invention relates to a power lift device for tractors. More specifically, it relates to a hydraulically operated device for supplying liquid under pressure to independent lifting units adapted to adjust implements connected-to an agricultural tractor. i

The principal object of the invention is the construction of a hydraulic power lift system incorporating a single control unit operable to positively and independently actuate a plurality of independent lifting means located at different places on a tracto r Another object is to provide an improved consecutive lift for the front and rear implements of an agricultural tractor.

Another object is the provision of an actuating means for a hydraulic control unit which has a cycle of operation effective to operate a plurality of hydraulic units in the desired order.

The above objects and others, which will be apparent from the detailed description to follow, are accomplished by utilizing individual hydraulic cylinder units for the front and rear implements mounted on an agricultural tractor. The pump for the hydraulic unit is driven from a power' shaft ofthe tractor. The control unit for delivering liquid under pressure to the lifting cylinders is manually controlled by a valve mechanism. Said mechanism is operated on a cycle made possible by the use of a ratchet device. By means of a ratchet device on a cam shaft, different valves controlling different fluid passages may be consecutively operated in a predetermined sequence. By this means, pressure may be applied consecutively to the lifting cylinders and released in the same order. Provision is also made for neutral positionswith the implements either lifted or in operating position.

In the drawings: t

Figure l is a side elevation of an agricultural tractor of the general purpose type with one of the rear wheels removed to better show the implements mounted thereon;

Figure 2 is a plan view of a portionof the implement connection at the rear of the tractor;

Figure 3 is'a front elevation of a portion of the implement connection at the front of the tractor;

Figures 1 and 6; g

Figure 5 is a cross'section through the lifting cylinder used atthe front of the tractor;

Figure 6 is a section taken on the line 6-8 of.

Figure 4;

Figur 4;

Figure 4 is a vertical section on the line 4-4 of Figure '1 is a section taken on the line 1-1 of Figure 8 is ,a section taken on the line 8-8 of gure 4;

-Figure.9 is an end view of the ratchet mem- 5 her utilized in the manual control; 1

Figure 10 is a diagrammatic view of the control shaft, cams carried thereby, and the valves operated by the cams, showing one position in the cycieof operation;

Figures 11, 12, 13 and 14 show the same elements as Figure 10, illustrating the successive steps in the cycle of operation of the control de-- vice for the power lift constituting the invention;

Figure 15 is 'a sectional view on the line l5-l5 15 of Figure 10 showing one of the operating cams. The letters A, B, C, -D and E on the'flgure repre-'- sent the five positions of the cam with relation to the stem of the valve which it controls;

Figure 16 is a sectional view on the line l.6l6 of Figure 10 showing another of the control cams; and,

Figure 17 is a sectional view on the line l'I-I'l of Figure 10 showing the third control cam.

In the drawings, a tractor has been -shownsomewhat diagrammatically to illustrate implements and the lift connections with the power lift mechanism of the invention. Certain parts. of the tractor will be designated by numerals to form a basis for adequate description of imple- 3o ments and the power lift mechanism. I

The tractor is illustrated as a narrow frame I! connected' to, a rearwardly located casing II, which forms the transmission casing and the final drive housing. Lateraliy extending hous-' ings I! support the tractor axles IS on which drive wheels I are mounted.

At'the forward end of the tractor, steerable front wheels ii are mountedona steering post. l6 controlled by suitable mechanism from a 40 steering wheel il located within reach of the operator seated on a. seat I8 at the rear of the tractor.

At the forward end of the frame III, forwardly not been described in detail, as it forms a part 50' of the present invention only as illustrating an implement mounted at the front end of a trac- A beam 23 is pivotally connected by means of and upwardly extending plates [9 are rigidly se- 5 brackets 24 to the draft member 20. An impleg5 ment frame structure 28, which carries soil engaging elements, is supported by the'beam 23.

bar in the form of a pipe 29. Said push bar, at

its rear end, is telescopically received by the end portion of a member 30, which is pivoted to a manually adjustable lever 3|. Said lever forms in eflect a manually adjustable stop to limit rearward movement of the bar 28.

A spring pressure link 32 is pivotally connected to the plate 26 and to a bracket 38 on a transverse bar 38' secured near the forward end of the bar 29. This construction is conventional and has not been shown and described in detail.

' It is also to be understood that the draft bar 28 extends across the front of the tractor and that a plurality of implement beams 23 are attached thereto, as is conventional in this art.

A lifting member in the form of an inverted ball 34 is pivoted at its ends on the lugs 20 on the same axis as the lifting lever 28. Said bail is provided with a transverse stop 85 which engagesthe rear side of. the lifting lever 28 near its upper end. The ball is also provided with a rearwardly extending ear .38, to which a piston rod 31 of a hydraulically operated cylinder is pivotally connected.

The hydrauliccylinder 38, as shown in Figure 5, is of the pressure type. fluid being admitted under pressure through a coupling 38 at one end of a piston head 48. At theother side of the piston 48 at the other end of the cylinder, a bleed opening 4| has been shown for the escape of liquid leaking past the piston 40. Said passage may be controlled by a check valve 42 to prevent the free flow of air into the cylinder during reciprocation of the piston.

The cylinder 38 is pivotally mounted on a bracket 43 rigidly secured to the tractor frame. At the rear end of the tractor, a vertical attaching bracket 44 has been illustrated, as well as a rearwardly extending plate 45. An implement beam' 46 is pivoted to the bottom end of the bracket 44. A frame structure 46', secured to the beam 46, provides means for supporting soil engaging units. A pressure link 41, pivotally secured to the frame structure 46', is connected as illustrated in Figure 2 to a lever arm 48 formed integrally on a transverse rockshaft 48. Said rockshaft is rotatably mounted in the plates 45, it being understood that the construction at each side of the tractor is substantially the same. A quadrant 45, secured to-the plate 45, provides means for locking a-manually adjustable lever 41 rigid- 1y to the upwardly extending end portion 48' of the rockshaft 48.

A lifting lever 48, rigidly secured to a journal 50 rotatable on the shaft 48, is connected by a lifting link 5i to the frame structure 46. It will be noted that the lifting link 5| slidably extends through a trunnion-block 52 pivoted on the lifting lever 49. An adjustable stop 52' at the upment vertically.

A lifting cylinder 53 is pivoted on a bracket 54,

transmission shaft 55 is provided with an end mounting consisting of a ball bearing assembly 58. This assembly is mounted in one end portion of a housing 81, which supports a pump driving shaft 88 arranged in axial alignment with the shaft 55. The pump driving shaft 88 is driven from a nut 58 on the end of the transmission shaft 85 by means of a member keyed to the shaft I8 and formed with a driving portion engaging the nut 88.

The housing 51 is enlarged at its outer end and formed with an upper chamber BI and a lower chamber 82 surrounding the bearing portion for the outer end ofthe shaft 58. The two chambers are formed by a horizontal partition (i3. The

enlarged portion of the housing at this point also extends upwardly terminating in a flanged upper surface 84. The chamber 8i, which is the high pressure side of the pump, communicates with a passage 68 terminating at the surface 64. The chamber 82, which is at the low pressure side of the pump, is extended upwardly by means of a passage 86', also terminating at the surface 34.

An elliptical pump gear casing 81 is secured to the outer face ofthe housing 51 adjacent the chambers 8| and 82. Onepump gear 68 is keyed to the shaft 58 within the chamber formed by the casing 81. Another pump gear 68, shown in' dotted lines in Figure 6, is rotatably mounted on a stub shaft 10. A cover plate H, secured to the outer face of the casing 81, completes the pump chamber and forms outer Journals for the ends of the shafts 58 and Ill.

An opening 12, formed in the end wall separating the chamber 62 and the pump chamber, forms a fluid conduit for the delivery of fluid into the pump chamber. A similar. opening 18, formed in the end wall separating the chamber GI and the pump chamber, forms an outlet for the delivery of fluidunder pressure into the high pressure chamber and therefrom through the passage 65.

A control housing 14 is formed with a surfaced lower face 15, which is seated on the face 64 of the pump housing. Adjacent the face 15, the housing 14 is cored to provide the necessary passages for fluid distribution. As shown best in Figures 6 and 8, the discharge passage 65from the pump housing communicates with a passage 16 cored into the control housing from the lower wall thereof. The passage 16, as best shown in Figure 8, is formed with branches TI, 18 and I9. Said branches terminate in alignment with each other to provide for control valves positioned in a'single line, whereby a single cam shaft may be utilized for their operation.

Valve stem guides 80, extending upwardly above the terminal ends of the branches TI, 18 and 18, form guiding means, respectively, for valves 8|, 82 and 83. Said-valves are provided with conventional valve springs 84 and spring retainers 85, whereby the valves are urged in an upward direction.

A transverse cam shaft 88 is mounted in the housing 14 supported at each end by removable cams 88, 89 and 98 positioned to contact, re-

spectively, the stems of the valves .8I, 82 and 88. Adjacent the ends of the branch conduits 11,

tion of the pump casing adjacent the contact surface 68. Saidpassage, as shown in Figure 4, communicates with'adischarge opening adapted to be connected with a fitting 95, as shown in Figure 1, for delivering fluid through a conduit 98 to the cylinder 53 at the rear of the tractor.

The valve 83 controls fluid flow through a passage-way 98 adapted to be connected by means of a fitting 98 with a conduit 98' for supplying' fluid-to the fitting 39 on the cylinder 88st the front end of the tractor.

The valve carried by the central valve stem 82 controls fluid flow between the central branch 18 and the low pressure passage 88 leading to the inlet side of the pump. This valve may be, therefore, considered as'the by-pass valve. When it is opened, as shown in Figure 6, pressure is released from the pump. In connection with the above description of the passage- ways 94 and 91, attention is called to the section line on Figure 6, which cuts across the dividing wall between-the low and high pressure sides of the pump. This section accounts for the peculiar appearance of the chamber in Figure 4.

A ratchet member, 99, as-shown alone in Figure 9, is rotatably mountedon the cam shaft 86 in the position shown in Figure 4. Said member hasone lever arm 99. on which a pawl I88 is pivotally mounted. A compression spring I8I abuts a recess formed in the pawl I88 and a recess formed in an over-hanging extension I82 of the arm 99. Said spring, therefore, urges the pawl I88 toward the cam shaft.

Adjacent the ratchet member 99, a notched flange I83 is formed on the cam shaft 86. Five circumierentially spaced notches ii are formed on said flanges. As best shown in Figure 6, the notches have a face lying on a radius on the flange against which the pawl E88 abuts and a cam extending in the other direction.

The ratchet member 99 is formed with an actuating arm i851 Said arm is formed with an integral laterally extending end portion I88 positioned to abut stops I87 and 78 cast on the housing, to limit angular movement of the ratchet member in both directions.

The actuating arm I85 of the ratchet member 9B is provided with'an opening I89, into which the bent-over end of an actuating rod H8 is pivoted. A cotter-key holds said end in position. The other end of the actuating rod is similarly secured to a lever arm III rigidly clamped on an actuating shaft 2; Said shaft extends through the wall of the casing to form ,a means for connecting an operating lever I I3.

At each movement of the actuatingshaft, the I pawl l88' rotates the cam shaft one-fifth of a complete revolution in the direction shown in Figure 6. As shown in Figure 7, a tension spring H4 is connected to an ear 5 formed on the housing I4 and to a pin H6 formed on a. member m clamped to theactuating shaft n2. Said spring returns the actuating mechanism to its original position after operation to rotate=the cam shaft one-fifth of a revolution.

As also shown in Figure 'I, a spring pressed latch I I8, mounted in a hollow boss I I9 formed on the housing wall, is adapted to engage notches formed in a flange I28 mountedon the cam shaft adjacent one end. The notches in said flange are positioned to be engaged by the plunger H8 to hold the cam shaft in any of the positions to which it is moved by operation of the actuating shaft H2.

In the operation of the device above described,

89. There is, therefore, no back pressure on the pump and it runs idle without the use of any appreciable power. Assuming that the operator moves the actuating shaft M2 for a complete movement of the ratchet member 98, the pawl I88, in engagement with one of the notches I84, rotates the cam shaft an angular distance ofonefifth of a complete revolution. It will be noted n that Figure 18 shows a portion of the cam shaft 88 with the earns 88, 89 and 88 thereon,- and the valves 8|, 82 and' 83. This figure shows the valves in the same position as Figure 4, omitting the, valve springs and other parts to diagrammatically illustrate; in combination with Figures 11 to 14, inclusive, the entire cycle of operation of the cam shaft. Figures 15,16 and 17, which are taken on the section lines bearing the corresponding numbers on Figure 10, show the cams in their position with the by'pass valve 82' open. In the description, this position wilLbe designated as position A of the cam shaft. The succeeding positions, as labeled in Figures 15, 16 and 17, will be identified as positions B, C, D and E in the order named. Figure 10, then, corresponds to position A; Figure 11 corresponds to position B; Figure 12 corresponds to position C; Figure'l3corresponds to position D; and, Figure 14 corresponds to position E.

By movement of the cam shaft an angular distance of one-fifth of a complete revolution, the cams are brought into position B, as illustrated in Figure 11. In this position, the points B, as identifled in Figures. l5, l6 and 1?, lie over the stems of the valves. During rotation to position B, the cam 98 engages and opens the valve 83, thereby allowing liquid to flow from the front lifting cylinder through the passage-way 94 back to the low pressure side of the pump. The implements at the front of the tractor are lowered during this step of the operation.

When the cam shaft is moved another onefifth of a revolution, position C is attained, as shown in Figure 12. The cam- 88 has rotated around in this position to open the valve- 8|, thereby aliowingflow from the lifting cylinder back through the conduit 96 and the passage-way into the branch i7. and therefrom back to the low pressure side of the pump. By this step in the operation of the control device, the rear implement is lowered. It willbe noted in Figure 12 that the valve 83 remains open during they open-- ing of the valve 8!, thereby continuing the lowering action ofthe front cylinder, if it has not al- 10 the gear pump is continuously operated by means ready been completed The position shown in Figure 12 is, in a sense, a neutral position, as

front and rear implements are lowered and as there is no back pressure on the pump. 7

when the cam shaft is moved another step in its operation, the cams 88 and 89 move away from the; valves 8! and 82, thereby closing said valves.

in its operation to position E, as illustrated in Figure 14, the valve 83 is closed by movement of the cam 90, and the valve BI is opened by contact with the cam 88. Fluid under pressure is thereby supplied through the passage-way "and the conrear implement is raised to a lifted position. After completion of the rear lifting operation, the cam shaft is moved another one-fifth of the revolution to position A, as shown in Figure 10, thereby completing the entire cycle of operation. The implements, both front and rear, are in lifted position with the by-pass valve 82 open whereby there is no back pressure developed on the pump.

It is to be understood that applicants have shown and described only a preferred embodiment of their improved hydraulic power lift and controlling means, and that they claim as their invention all modifications falling within ,the

- scope of the appended claims.

What is claimed is:

l. A hydraulic control device, a casing, a fluid pump in the casing, an outlet conduit from said pump, said casing being formed with three valve chambers, each of said chambers being in communication with the pump outlet, three valves positioned to control fluid flow from said chambers, one of said valves controlling" flow to a hydraulic device, a second of said valves controlling flow to a second hydraulic device, and a third valve controlling return flow to the inlet of the pump. a cam shai'trotatably mounted in the casing, means for rotating said cam shaft a predetermined angular distance at each step of its 'movement, a cam on the shaft for each of the control valves, said cams being positioned at angles relative to each other and being provided with faces operable to-successively open the two valves to thehydraulic devices, open the third v 'valve to by-pass the fluid from the pump, and to successively open the other two valves while said valve remains open to by-pass fluid from the two hydraulic devices to the low pressure side of the p 2. A hydraulic control devicefor implement power lifts having a plurality of lifting cylinders connected to implements carried by a tractor comprising a casing on the tractor, means in said casing forengaging a drive element of the tractor, a fluid pump in the casing operable by said means, an outlet-conduit from said pump, three 7 valve chambers in communication with said conduit, valves positioned to control fluid flow through said-chambers, a conduit connecting'one of said chambers with one of the lifting cylinders,

a conduit connecting another of said chambers with. a second lifting ,cylinder and a by-pass conduit connecting the third chamber with the arcades inlet side of the pump, a cam shaft rotatably mountedin the casing, means for moving said cam shaft a predetermined number of degrees at each of the flve steps of movement, spring pressed latch means in engagement with said shaft operative to hold the shaft'in anyone of its adjusted positions, and a cam on the shaft for each of the 1 control valves, said cams being positioned at angles to each other andv being provided with faces operable to successively open the two valves to the power lift devices, to by-pass the fluid to the pump, and to successively by-pass fluid from the two power lift devices to the pump.

duit 96 to the rear lifting cylinder whereby the/ 3. A hydraulic control device for implement power lifts having a plurality of lifting cylinders connected 'to implements comprising a casing on the tractor, means in said casing for engaging a drive element of a tractor, a fluid pumpin the casing operable by said means, an outlet conduit from said pump, said casing being formed with three valve chambers in communication with 'said conduit, a valve controlling fluid flow from each of said chambers, one of said valves controlling flow to one of the lifting cylinders, a

second of said valves controlling flow to a second lifting cylinder and a third valve controlling return flow to the low pressure inlet side of the' pump, a camshaft rotatably mounted in the casingfimeans for moving said cam shaft a predetermined number of degrees at each of the 'flve steps of its movement, and a cam on the shaft for each of the control valves, said cams being positioned at angles relative to each other.

and being provided with faces operable to suecessively open the two valves to the power lift cylinders for lifting the-implements, to by-pass the fluid from the pump, and to successively bypass fluid from the two power lift cylinders to -the low pressure side of the pump for lowering the implements.-

I 4. A, hydraulic control device for implement power lifts having a plurality of lifting cylinders connected to implements ."carried by a tractor comprising a casing on the tractor, means in fsaid casing for engaging a drive element of a tractor, a fluid pump in the casing operable by said means, an outlet conduit from said pump, said casing being formed with three valve chambars in communication with said conduit, a valve controlling fluid flow from each of said chambers, one of said valves controlling flow to one of the lifting cylinders, a second of said valves controlling flow to a second lifting cylinder and with faces operable to successively open the two valves to the power lift cylinders for lifting the,

implements, to by-pass the fluid from the pump, and to successively by -pass fluid from the two power lift cylinders to the low pressure side 0 the pumpfor lowering the implements.

5. A hydraulic control device for implement power lifts having a plurality of lifting cylinders connected toimplements carried by a tractor' casing being formed with three valve chambers in communication with said conduit, valves posi tioned to control fluid flow through said'chambers, a conduit connecting one of said chambers with one of the lifting cylinders, a conduit connecting another of said chambers with a second lifting cylinder and a by-pass conduit connecting the third chamber with the inlet side of the pump, a valve operating cam shaft rotatably mounted in the casing, manually operated ratchet means for moving said cam shaft in one direction only a predetermined number of degrees 'at each of the five steps of its movement, and a cam on the shaft for each of the control valves, said cams being positioned at angles relative to each other and being provided with faces operable to successively open the two valves to the power lift devices, to by-pass the fluid to the pump; and

to successively by-pass fluid from the two power lift devices to the pump.

6. A hydraulic control device comprising 8. casing formed with three communicating valve chambers to which fluid is to be supplied under pressure, three valves positioned to control fluid flow from said chambers, one of said valves controlling flow to a hydraulic device, a second of said valves controlling flow. to a second hydraulic device and a third valve forming a lay-pass. and relief valve, a cam shaft rotatably mounted in the casing, means for rotating said cam shaft a predetermined angular distance at each step of its movement, and a cam on the shaft for each of the control valves, said cams being positioned .at angles relative to each other and being pro-:

vided with faces operable to successively open the two valves to the hydraulic devices, open the by-pass valve, and to successively open the other two valves while said by-pass valve remains open to provide for return flow of fluid from the two hydraulic devices.

7. A hydraulic control device comprising a casing formed with three communicating valve chambers to which fluid is to be supplied under pressure, three valves positionedto control fluid flow from said chambers, one of said valves controlling flow to a hydraulic device, a second of said valves controlling flow to a second hydraulic device and a third valve forming a by-pass and 'relief valve, a cam shaft rotatably mounted in the casing, manually operated ratchet means for rotating said cam shaft a predetermined angular distance at each of the five steps of its movement to complete one revolution, and a cam on the shaft for each of the control valves, said cams being positioned at angles relative to each other and being provided with faces operable to successively open the two valves to the hydraulic devices, open the by-pass valve, and to successively open the other two valves while said by-pass valve remains open to provide for return flow of fluid from the two hydraulic devices.

EDWARD A. JOHNSTON. ALEXUS C. LINDGREN.

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