US3525212A

US3525212A - Variable stroke control device for remote hydraulic piston and cylinder assemblies

Info

Publication number: US3525212A
Application number: US755079A
Authority: US
Inventors: William Gallant
Original assignee: METERED HYDRAULICS Ltd
Current assignee: METERED HYDRAULICS Ltd
Priority date: 1968-08-26
Filing date: 1968-08-26
Publication date: 1970-08-25
Anticipated expiration: 1987-08-25

Description

Aug. 25, 1970 w. GALLANT VARIABLE STROKE CONTROL DEVICE FOR REMOTE HYDRAULIC PISTON AND CYLINDER ASSEMBLIES Filed Aug. 26, 1968 2 Sheets-Sheet 1 Q Q i UP -fll *z [8 DOWN UP ADJUST DOWN 5 44 ,5 TAM/5T IO DOWN 2 NJ I4 I Q-j- UP [6.

4424/9/ 7 gem/Y7 Aug. 25, 1970 w, GALLANT 3,525,212

VARIABLE STROKE CONTROL DEVICE FOR REMOTE HYDRAULIC PISTON AND CYLINDER ASSEMBLIES Flled Aug 26, 1968 Z Sheets-Sheet 2 United States Patent 3,525,212 VARIABLE STROKE CONTROL DEVICE FOR REMOTE HYDRAULIC PISTON AND CYLIN- DER ASSEMBLIES William Gallant, Roblin, Manitoba, Canada, assignor to Metered Hydraulics Ltd., Brandon, Manitoba, Canada Filed Aug. 26, 1968, Ser. No. 755,079 Int. Cl. F15b 7/00, 13/04 US. Cl. 6054.5 9 Claims ABSTRACT OF THE DISCLOSURE My invention relates to new and useful improvements in control devices for hydraulic piston and cylinder assemblies, particularly remotely situated hydraulic piston and cylinder assemblies as used on agricultural implements or the like.

It is conventional to provide a pump which produces hydraulic pressure in a control valve adjacent the operator which directs this pressure fluid through hoses or conduits to either front or rear of the work cylinder thus causing the plunger to move in and out thereby lowering and raising the implement components requiring control. For example, it is normal to control the depth of penetration of one-way discs, combine reels and the like.

The control valve is normally actuated manually from a pre-set neutral position. A detent is available on some valves that hold the lever in the up or down position until the work cylinder has completed its travel or stroke.

When the work cylinder lowers the implement component, the down stroke travel must be controlled as this regulates the depth of penetration of the implement component within the soil. This is usually controlled by various mechanical means such as blocking the down stroke that must be manually adjusted on the work cylinder and once adjusted cannot be varied during operation to suit conditions but rather the machine has to be halted and the adjustment made.

A further system uses a valve built into the work cylinder that stops the flow of hydraulic fluid when actuated by a preset collar on the plunger. This system also must be preset before work commences and cannot be varied during use without stopping the implement.

It is generally recognized, especially with the relatively large implements in use today, that variable depth control is essential and the purpose of the present invention is to provide a simple means of positive depth control or stroke control, operable at any time from the driving seat of the implement or towing vehicle without the necessity of stopping the machine to achieve this control.

I achieve this by providing a control piston and cylinder in series with one of the conduits between the pump and the work cylinder. A further conduit together with a further control valve is adapted to bypass this control piston and cylinder so that the position of the work piston can be preset by this control valve whereupon same is closed and the work piston is then actuated by the freely floating piston within the control piston and cylinder assembly.

3,525,212 Patented Aug. 25, 1970 A further embodiment incorporates a proportional valve in the event that the work cylinder is of a relatively large displacement compared to the control cylinder so that only part of the fluid flow is permitted to enter the control piston and cylinder assembly.

The principal object and essence of the invention is therefore to provide a control piston and cylinder assembly together with a control valve and bypass conduit which enables the work cylinder piston to be prepositioned thus controlling the length of the down stroke thereof.

Another object of the invention is to provide a device of the character herewithin described which can readily be fitted to existing equipment and can include a proportioning valve in the event that the work cylinder is of a considerably larger displacement than the control cylinder.

A yet further object of the invention is to provide a device of the character herewithin described which is simple in construction, economical in manufacture, and otherwise well suited to the purpose for which it is designed.

With the foregoing in view, and such other objects, purposes or advantages as may become apparent from consideration of this disclosure and specification, the present invention consists of the inventive concept in whatsoever way the same may be embodied having regard to the particular exemplification or exemplifications of same herein, with due regard in this connection being had to the accompanying figures in which:

FIG. 1 is a schematic view of my device shown incorporated within an hydraulic system.

FIG. 2 is an enlarged sectional view of a control piston and cylinder assembly together with a sectional view of the proportioning valve assembly.

FIG. 3 is a schematic view showing one embodiment of the two control valves utilized in the system.

In the drawings like characters of reference indicate corresponding parts in the different figures.

Proceeding therefore to describe my invention in detail, reference should be made first to FIG. 1 which shows schematically the incorporation of my invention in an hydraulic system.

Reference character 10 illustrates a work cylinder having a piston 11 therein secured to a piston rod 12 which extends from one end 13 of the work cylinder. This portion of the apparatus is normally situated on the agricultural implement and the end 14 of the piston rod 12 is connected to the implement component operated hydraulically as, for example, the blades of a cultivator.

For purposes of clarification, it is assumed that in this instance the piston rod 12 is connected to an implement component so that when the piston 11 moves in the direction of arrow 15, the implement is lowered or penetrates the soil and when the piston 11 is moved in a direction opposite to arrow 15, then the implement component is raised.

Also for clarification, the end 16 of the cylinder 10 is defined as the down side of said cylinder and the aforementioned end 13 is considered to be the up side of the cylinder.

A conduit 17 is connected to the cylinder 10 adjacent the end 13 thereof and extends, via conventional flexible hosing, to the tractor or source of power and is connected to a control box shown schematically in FIG. 3 and collectively designated 18.

This control box includes-the fluid reservoir 19, a fluid pressure pump 20, and a control valve assembly collectively designated 21. This control valve is conventional in construction and is shown schematically in FIG. 3, it consists of a body portion 22 which is apertured longitudinally to receive a shuttle valve 23. This shuttle valve is provided with

relieved portions

24, 25 and 26 along the length thereof. A conduit from pump 20 leads into the body portion 22 and thence to the axial bore therein at two locations, namely 20A and 20B. Conduit 17 is connected through the body portion adjacent the relieved portion 24 and conduit 27 passes through the body portion and connected to the relieved portion 26.

Conduits 20C extend from the body poltion to the reservoir 19. With the shuttle valve in the position shown in FIG. 3, there is no connection between

conduits

20A and 20B from the pump to the valve as these are blanked off in this position by the body of the shuttle valve.

However, oil being circulated by the pump passes through the bypass conduit 20D, through the relieved portion 25 and thence is returned to the reservoir '19.

The aforementioned conduit 27 extends to a control piston and cylinder assembly collectively designated 28, the conduit 27 entering the cylinder 29 of the assembly 28 adjacent the end thereof.

This conduit 27 extends operatively from adjacent the end 31 of the cylinder 29 to the end 16 of the work cylinder so that in eflect conduit 27 consists of a first portion connected to end 30 of cylinder 29 and a further portion extending between the end 31 of cylinder 29 and the end 16 of cylinder 10, thereby placing cylinder 29 in series between the control valve 21 and the work cylinder 10.

Reciprocal within cylinder 29 is a free moving piston 32, conventional seals being provided therearound to prevent leakage of fluid therepast.

The aforementioned valve 21 is capable of three positions, firstly the neutral position shown in FIG. 3 and hereinbefore described.

The second position may be termed the down position occurs when the shuttle valve 23 is moved downwardly thus connecting conduit 17 to conduit 20B through the relieved portion 24. This downward movement also connects conduit 27 to the reservoir conduit 20C through the relieved portion 26. In this position, fluid under pressure from pump 20 flows through conduit 20B into relieved portion 24 and thence to conduit 17 thus moving piston 11 within cylinder 10, in a direction of arrow 15. Fluid displaced by piston 11 travels via conduit 27 into cylinder 29 and moves freely floating piston 32 also in the direction of arrow 15. Fluid displaced by the freely moving piston 32 travels along conduit 27, through relieved portion 26 and thence to the reservoir through 20C. This action lowers the implement component connected to the end 14 of the piston rod 12 and it will be observed that the lower action will continue until piston 11 abuts end 16 or until piston 32 abuts end 30 of the cylinder 29 at which time, of course, no further movement can take place.

If the shuttle valve 23 is in the up position, then conduit 20A, extending from the pump 20, connects to conduit 27 through relieved portion 26 and conduit 17, connects to reservoir conduit 20C, through relieved portion 24.

Under these circumstances, fluid under pressure flows through conduit 27, thus moving piston 32 along cylinder 29 and displacing fluid through the further portion of conduit 27, into the end 16 of cylinder 10. This moves piston 11 in a direction opposite to arrow thus raising the implement component connected to the end 14.

Fluid displaced by piston 11 travels along conduit 17 through relieved portion 24 and thence to the reservoir via C.

Arrows placed adjacent the

conduits

17 and 27 are labelled up and down and refer to the movement of the implement component secured to piston rod 12. It will be appreciated that the operation of the device as hereinbefore described is relatively conventional with the exception that cylinder 29 is in series with conduit 27.

However, in order to adjust the end of the down stroke of piston 11, I provide a further conduit 35 extend ing from the portion of conduit 27 connected to the end 31 of the cylinder 29. This conduit 35 is connected to the aforementioned control box 18.

Within this box is a further control valve collectively designated 36. This is similar in construction to the control valve 21 and has been given prime numbers.

The shuttle valve 23' operates in the same manner as hereinbefore described between the neutral position, the down position and the up position.

For the purpose of illustration, the adjustment of the device is made with the freely floating piston 32 abutting against end 30 of cylinder 29 or in other Words, at the maximum down position.

At this point, shuttle valve 23' is returned to the neutral position by the conventional spring (not illustrated) with the system locked and pump 20 merely circulating fluid through conduit 20D to the reservoir.

At this point control valve 23' is operated in either of the two positions depending upon the position it is desired to preset piston 11. If we assume for the moment that piston 11 is also against end 16 of the cylinder 10, in other words, in the maximum down position and it is desired to reset the down position and the up position.

For the purpose of illustration, the adjustment of the device is made with the freely floating piston 32 abutting against the end 30 of cylinder 29 or in other words, at the maximum down position.

At this point, shuttle valve 23 is returned to the neutral position by the conventional spring (not illustrated) with the system locked and pump 20 merely circulating fluid through conduit 20D to the reservoir.

At this point control valve 23 is operated in either of the two positions depending upon the position it is desired to preset piston 11. If we assume for the moment that piston 11 is also against end 16 of the cylinder 10, in other words, in the maximum down position and it is desired to reset the down position to a lesser degree of penetration then the shuttle valve 23' is moved upwardly to connect pump conduit to conduit 35 and conduit 17 to reservoir via conduict 200.

When the valve 23 is in the above mentioned position, fluid under pressure from the pump 20 flows through relieved portion 26' and into conduit 35. Inasmuch as piston 32 is deadended against end 30 and the system is locked in any event, fluid passes down conduit 35 and into the portion of conduit 27 connected to the end 16 of cylinder 10. This moves piston 11 in the direction opposite to arrow 15, any fluid being displaced passing through conduit 17, and thence through relieved portion 24' to the reservoir. This raises the implement component and when it has been raised to the point where the depth penetration is sutficient, valve 23' is moved back to the neutral position.

Valve 23 is then operated to move piston 32 towards end 31 of the cylinder thus moving piston 11 towards the end 13, of cylinder 10 thus raising the implement component. When the implement component is lowered by changing the position of valve 23, free floating piston 32 strikes the end 30 of cylinder 29 at the same time that piston 11 reaches the maximum down position orginally preset. This piston 11 cannot travel any further because the system is now locked so that the depth control is effective.

It will also be appreciated, of course, that by changing the position of valve 23, the piston 11 can be moved in the direction of arrow 15 so that piston 11 can be positioned anywhere within cylinder 10 and it will not exceed these limits when operated by the action of piston 32.

The aforementioned embodiment presupposes

cylinders

29 and 10 being of similar volumetric capacity.

However, occasionally cylinder 10 is of relatively large capacity and it is not desirable to provide a similarly large cylinder 29.

Under these circumstances, I can utilize the embodiment shown in FIG. 2 which incorporates a proportioning valve assembly collectively designated 36A.

This proportioning valve assembly is provided so that the flow of fluid into cylinder 29 may be limited. In other words the fluid flow is divided by the proportioning device 36.

It consists of a body portion 37 which is hollow internally and the portion of the conduit 27 extending from the end 31 of cylinder 29, is connected via nut 38, to one end 39 of this body portion.

A conduit 40 extends from end 30 of cylinder 29 to adjacent end 41 of the body portion 37.

The first portion of conduit 27 connected to the end 30 of the cylinder 29, extends inwardly and is provided with a flared valve seat 42. Spring loaded ball 43 is carried within one side 44 of piston 32 and when piston 32 reaches the end 30 of the cylinder, the ball engages the seat 42 on the end of conduit 27 thus cutting ofl the flow. This relieves the pressure against the seals around the piston and also prevents shock loading occurring.

A cylindrical sleeve valve 45 extends within the end 41 of the body portion 37 of the proportioning valve, the inner end 46 of the sleeve valve being tapered and adapted to engage a tapered seat 47 situated within the body portion 37 intermediate the ends thereof. This sleeve valve is screwthreadably secured within a gland nut 48 which in turn is screwthreaded within the end 41. A disc 49 or the like is secured to the end of the sleeve valve so that it can be manipulated by the operator.

A stern valve 50 is screwthreadably engaged concentrically within the sleeve valve 45 and extends clear through. This terminates in a valve head 51 reversed to valve end 46 and this valve head is engageable within a seating 52 within the body portion between valve seat 47 and end 39 thereof.

This valve 51 is reversed to valve 46. A passage or drilling 53 extends from the body portion 37 between valves 47 and 52 and is connected via a conduit 54. to the end 16 of the work cylinder 10. This conduit 54 is in fact a portion of the aforementioned conduit 27.

A drilling 55 extends between the body portion 37 and housing 54 between valve 52 and the end 39 and a check valve in the form of ball 56, rests upon a seating 57 within this driling. A very light spring 56' maintains the ball on the seating 57.

Finally, a further drilling or conduit 58 extends be tween the body portion 37 and housing 54 and is situated between valve seating 47 and the end 41 of the body portion and a ball valve 58' engages seating 58", a relatively heavy spring maintaining this ball upon the seat.

In operation, this particular embodiment is used when the work cylinder has a greater displacement than the control cylinder 29. In this embodiment and with the proportioning valve in use, the piston 32 travels the full length of the cylinder 29 and the depth control of piston 11 is controlled by the rate at which piston 32 is permitted to travel towards the left-hand end 30.

The valve 49 controls the division of flow of fluid passing through housing 54 and it should be observed that valves 46 and 51, once they are preset, work in opposition to one another. In other words, if valve 46 is opened more, then valve 51 closes slightly. This proportions the flow of fluid passing through conduit 27 and conduit 40. The greater quantity of fluid permitted to pass through conduit 27, the faster piston 32 will move towards end 30 and stop the piston 11 from travelling downwardly any further. It will therefore be seen that the depth of the implement controlled by piston 11 is controlled by the opening and closing of the valve 49 which in turn controls the rate of travel of piston 32.

As soon as ball valve 43 engages the valve seat 42, the system is locked and the piston 11 cannot travel downwardly any further. When the implement is raised, the

fluid flow is reversed as hereinbefore described and piston 32 moves towards the end 31 displacing fluid before it, through conduit 27. This fluid lifts the valve 56 which is held with a very light spring, and fluid flows through the drilling 55, through conduit '54 and into cylinder 10 thus moving piston 11 in the direction opposite to arrow 15 and raising the implement. It should be noted that the spring loaded valve 56 always unloads prior to the spring loaded valve 58'. This ensures that piston 32 always engages end 31 of cylinder 29 and then if piston 11 has not reached the end of its stroke, fluid under pressure passes through conduit 40 and through the heavier loaded spring valve 58 thus ensuring that piston 11 completes its stroke.

Valves 46 and 51 are adjusted so that in order to provide restrictive control which is essential so that positive pressure develops upon the right hand side of the piston 32 (with reference to 'FIG. 2) this ensures that this piston moves towards end 30 and provides a ditferential in pressure upon either side of the piston, the fluid passing through conduit 40, venting through conduit 27.

Once the relationship between valves 46 and 51 has been set by rotation of shaft 50, it is not normally necessary to reset these. The down position of piston 11 is set by wheel or disc 49 which, of course, rotates over valve 46 and valve 51-.

However, during operation it is sometimes necessary to adjust temporarily'the draft of the implement and in these circumstances, of course, the control valve 23' is operated through conduit 35 thus bypassing the portioning valve assembly. Once this condition has passed, the control valve is returned to neutral and the relationship between piston 11 and piston 32 is restored.

Finally it should be observed that ball valve 43 is desirable in both embodiments in order to relieve hydraulic pressure from the seals surrounding piston 32 and to prevent mechanical shock from occurring as piston 32 reaches the end 30 of the cylinder 29.

With the ball valve 43 closing 01f conduit 27, where fluid under pressure passes through conduit 27, the ball valve is immediately displaced against the spring pressure thus enabling the fluid pressure to operate against piston 32.

Although the foregoing deals with down" stroke control normally required when the device is used with agricultural equipment, nevertheless it will be appreciated that the device can be used to control both down and up strokes depending upon the design parameters of the equipment being controlled.

What is claimed to be the present invention is:

1. A variable stroke control device for use with a work piston and cylinder assembly, a fluid pump assembly, a control valve assembly, a first conduit extending between said control valve assembly and the up side of said cylinder and a second conduit extending between said control valve assembly and the down side of said cylinder; said variable stroke control device being operatively connected in series with said second conduit and including a control cylinder, and a free floating piston therein, said second conduit including a portion connecting with said control cylinder on one side of said free floating piston and a further portion connecting with said control cylinder on the other side of said free floating piston, said portion connecting to said control valve assembly, said further portion connecting to said down side of said work cylinder, a work-piston-positioning valve assembly operatively connected between said pump and the down side of said cylinder bypassing said control cylinder, and means to actuate said work-piston-positioning valve assembly.

2. In a hydraulic system including a source of fluid pressure, a work piston and cylinder assembly, a control valve between said source of fluid pressure and said work piston and cylinder assembly, a first conduit extending from said control valve to the down side of said work piston and cylinder assembly, and a second conduit extending between said control valve and the up side of said work piston and cylinder assembly; means to preset the down position of said piston within said cylinder and further means to prevent said piston from moving past said preset position on the down stroke of said piston, said second means comprising a control cylinder in series with said first conduit and a free floating piston in said control cylinder.

3. The device according to claim 2 in which said first means includes a second control valve operatively connected to said source of fluid pressure, a bypass conduit extending between said second control valve and the said down side of said work cylinder.

4. The device according to claim 1 which includes a proportioning valve assembly operatively connected between said control piston and cylinder and the down side of said work cylinder for adjustably controlling the volume of fluid passing into said control piston and cylinder.

5. The device according to claim 2 which includes a proportioning valve assembly operatively connected between said control piston and cylinder and the down side of said work cylinder for adjustably controlling the volume of fluid passing into said control piston and cylinder.

6. The device according to claim 3 which includes a proportioning valve assembly operatively connected between said control piston and cylinder and the down side of said work cylinder for adjustably controlling the volume of fluid passing into said control piston and cylinder.

7. The device according the claim 4 in which said proportioning valve assembly is connected to said further portion of said second conduit, said proportioning valve assembly including a body portion, an adjustable fluid flow dividing assembly in said body portion, said fluid flow dividing assembly including an adjustable sleeve valve, a seat for said valve, an adjustable stem valve con centrically mounted in said sleeve valve, the seat for said stem valve, said sleeve valve and said stem valve being 8 independently adjustable to control the division of fluid flow in one direction through said valve, and check valves in said proportioning valve to permit unrestricted fluid flow in the other direction through said valve.

8. The device according to claim 5 in which said proportioning valve assembly is connected to said further portion of said second conduit, said proportioning valve assembly including a body portion, an adjustable fluid flow dividing assembly in said body portion, said fluid flow dividing assembly including an adjustable sleeve valve, a seat for said valve, an adjustable stem valve concentrically mounted in said sleeve valve, the seat for said stem valve, said sleeve valve and said stem valve being independently adjustable to control the division of fluid flow in one direction through said valve, and check valves in said proportioning valve to permit unrestricted fluid flow in the other direction through said valve.

9. The device according to claim 6 in which said proportioning valve assembly is connected to said further portion of said second conduit, said proportioning valve assembly including a body portion, an adjustable fluid flow dividing assembly in said body portion, said fluid flow dividing assembly including an adjustable sleeve valve, a seat for said valve, an adjustable stem valve concentrically mounted in said sleeve valve, the seat for said stern valve, said sleeve valve and said stern valve being independently adjustable to control the division of fluid flow in one diretcion through said valve, and check valves in said proportioning valve to permit unrestricted fluid flow in the other direction through said valve.

References Cited UNITED STATES PATENTS 2,733,691 2/1956 Johnson 9213 3,111,062 11/1963 Peros 9213 PAUL E. MASLOUSKY, Primary Examiner U.S. Cl. X.R.