US3842714A

US3842714A - Combine hydraulic valve

Info

Publication number: US3842714A
Application number: US00325957A
Authority: US
Inventors: M Coleman
Original assignee: Allis Chalmers Corp
Current assignee: Deutz Allis Corp
Priority date: 1973-01-22
Filing date: 1973-01-22
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22
Also published as: CA994207A

Abstract

A control valve consisting of two-way normally closed solenoid poppet valves and two stage normally open solenoid poppet valves. The normally closed solenoid valves are arranged to direct flow to and from a cylinder in the desired manner. For the control of each single acting cylinder, one normally closed solenoid valve is required, whereas, for a double acting cylinder, four normally closed solenoid valves are needed. These sets of solenoid valves are incorporated in a single body or manifold to control the different functions on a combine such as reel height, reel speed, auger swing and traction drive. The control valve also includes a low flow circuit relief valve set at 2,000 psi and a 600 psi solenoid valve functioning as a relief valve to satisfy maximum pressure conditions for reel speed operation. The valve is located near to a supply pump and the pump flow passes through the normally open two-way solenoid valve and back to sump to minimize pressure drop in neutral.

Description

United States Patent [191 Coleman COMBINE HYDRAULIC VALVE [75] Inventor: Martin W. Coleman, Independence,

[73] Assignee: Allis-Chalmers Corporation,

Milwaukee, Wis.

22 Filed: Jan. 22, 1973 21 Appl. No.: 325,957

[52] US. Cl 91/459, 91/414, 60/D1G. 2, 60/471 [51] Int. Cl. F151) 13/044 [58] Field of Search 91/414, 459; 60/D1G. 2, 60/471 [56] References Cited UNITED STATES PATENTS 2,318,851 5/1943 Griffith 60/97 P 2,425,391 12/1947 Parsons 2,643,515 6/1953 Harsch 2,984,985 5/1961 MacMillin 3,494,258 2/1970 Harms et al. 3,550,506 12/1970 Gardenhour 3,793,831 2/1974 Khatti 91/414 REEL LIFT AUGER SWING [451 Oct. 22, 1974 Primary ExaminerEdgar W. Geoghegan Assistant Examiner-William F. Woods Attorney, Agent, or Firm-Kenneth C. McKivett 5 7] ABSTRACT A control valve consisting of two-way normally closed solenoid poppet valves and two stage normally open solenoid poppet valves. The normally closed solenoid valves are arranged to direct flow to and from a cylinder in the desired manner. For the control of each sin gle acting cylinder, one normally closed solenoid valve is required, whereas, for a double acting cylinder, four normally closed solenoid valves are needed. These sets of solenoid valves are incorporated in a single body or manifold to control the different functions on a combine such as reel height, reel speed, auger swing and traction drive. The control valve also includes a low flow circuit relief valve set at 2,000 psi and a 600 psi solenoid valve functioning as a relief valve to satisfy maximum pressure conditions for reel speed operation. The valve is located near to a supply pump and the pump flow passes through the normally open twoway solenoid valve and back to sump to minimize pressure drop in neutral.

2 Claims, 4 Drawing Figures TRACTION DRIVE REEL SPEED PMENIEDBUZZW AUGER SWING REEL LIFT Z TRACTION DRIVE72 REEL SPEED B131 7853? TO OPERATE ENERGIZE VALVE SOLENOI DS RAISE 39 +4! REEL LIFT LOWER 4' UP 3e,a9+4-3 AUGER SW'NG BACK aza9+42 FASTER 39+44 TRACTION DRIVE SLOWER v44 RAISE 38 39 REEL SPEED LOWER 39 46 PAIENIEB 0m 2 2 I914 3.842.714 am at 'a WK wzao zoFu/ki mv w mm COMBINE HYDRAULIC VALVE CROSS REFERENCE TO RELATED APPLICATION This invention is an improvement over the combine control shown in copendng US. application Ser. No. 260,741, filed June 8, 1972, now Pat. No. 3,793,831.

BACKGROUND OF THE INVENTION In a combine there are a number of power operated devices which must be controlled by an operator at a remote operators station. It has been found desirable to employ a hydraulic control system in which some devices are controlled at a high pressure level and at least one device is controlled at a low pressure level. In order to increase the efficiency of the system, it has heretofore been proposed to use an electric over hydraulic system (such as shown in US. Pat. No. 3,793,831) wherein a control manifold, with electrically operated solenoid valves, is placed near the pump and electric switches for controlling the electrically operated valves are placed in a console at the operators station. In such prior art control system, a separate relief valve is placed in one branch circuit to establish a lower pressure level for one control motor.

SUMMARY OF THE INVENTION The electric over hydraulic control system of this invention includes a hydraulic manifold having two pairs of normally closed solenoid valves controlling flow to a double acting hydraulic cylinder without the need of separate check valves. Another feature of this invention is a combine control in which a single acting hydraulic cylinder is controlled by a pair of normally closed solenoid valves one of which serves (1) as a relief valve when not energized and (2) as a dumping valve (to achieve a control function) when energized.

An object of this invention is to provide an improved electrohydraulic control valve for controlling functions performed by single and double acting cylinders in an open center hydraulic system in a combine harvester.

Another object of this invention is to provide an inexpensive electrohydraulic control valve that will perform the functions of three-way and four-way spool valves with lockout check valves on mobile equipment.

Another object of this invention is to provide twoway solenoid valves in an open center hydraulic circuit to perform functions previously performed by three and four-way spool valves with lockout check valves.

Another object of this invention is to provide a hydraulic system wherein solenoid valves provide one or more functions at lower pressure than system pressure.

A further object of this invention is to provide a hydraulic circuit having a hydraulic cylinder and utilizing solenoid valves and in which each solenoid valve works as a directional control valve to control direction of flow and as a check valve to a) isolate each function from the others in the circuit; and b) hold the hydraulic cylinder in activated position.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings:

FIG. 1 is a side elevation of a combine harvester embodying the invention;

FIG. 2 is a schematic view of the invention;

FIG. 3 is a section view through the valve body partially shown schematically; and

FIG. 4 is a summary of functions provided by various combinations of the solenoid valves.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to FIG. 1, the invention is embodied in a self-propelled combine harvester 10 having a main frame 11 providing an operator station 12, a grain tank 13 provided with a swingable grain unloading auger 14, an internal combustion engine 15, an operators control console 16 and a harvesting and threshing and cleaning mechanism 17 including a reel 18 mounted on the forward end of combine 10. The foregoing are supported at the forward end of frame 11 on traction wheels 19 which are operatively connected to engine 15 by conventional means (not shown). The rearward end of the combine 10 is supported on dirigible wheels 20 operatively connected to steering wheel 21.

Mounted in the operators console 16 is a group of electrical switches 22, 23, 24 and 26 (FIG. 2) which are positioned for easy manipulation by the operator when positioned at station 12 (FIG. 1).

A valve body or hydraulic manifold 27 is positioned centrally on frame 11 in reasonably close relation to pump 28, sump 29 and the functions of the combine to be hydraulically controlled. Pump 28 is operatively connected to engine 15 by conventional means (not shown). Valve body 27 (FIG. 3) is provided with a main passage 31 connected at one end to conduit 32 to provide a passage between pump 28 and main passage 31. A conventional relief valve 33 is interposed between conduit 32 and conduit 34 leading from sump 29 to pump 28.

Solenoid valves

36, 37, 38, 39, 41 and 42 are mounted in valve body 27 in communication with main passage 31.

Solenoid valves

43, 44 and 46 are also mounted in valve body 27 in communication with main passage 31. Consider solenoid valve 36 which is a normally closed direct acting'solenoid valve and normally open two stage solenoid valve 39 are arranged as shown in FIG. 3. For the present discussion, consider that only these two valves are installed in the valve body 27 and the other valves are not present in FIG. 3.

Pump 28 is connected to the valve inlet port 47 of main passage 31. The pump flow with none of the switches 22-26 (FIG. 2) actuated is as follows: the flow (FIG. 3) goes through

passages

31, 48, 49, 51 and line 52 to the sump 29. Plunger 53 in solenoid valve 41 seats tight on the seat 54 and blocks the passage of flow from a motor or cylinder 56 to a motor passage or cavity 57. Valve 41 serves as a lock or check valve to hold cylinder pressure constant and also serves as a directional control valve to direct flow from cylinder 56 to cavity 57.

To extend reel lift cylinder 56, solenoid valves 39 and I 41 are energized by pushing switch 22 upwardly. When coil 58 (FIG. 3) of solenoid valve 39 is energized, plunger 59 thereof moves and seats on poppet 61 which in turn moves together with plunger 59 and seats on valve seat 62 blocking flow between passages 48 and 49. The flow from pump 28 is now blocked from sump 29 and is available for any of the functions comprehended by the valves in valve body 27. The energization of coil 63 of valve 41 causes plunger 53 to move away from seat 54 allowing hydraulic fluid to flow from passage 47 to cavity 57. When the pressure in cavity 57 exceeds the pressure in cylinder 56, the pump flow passes through passage 67, 68 and orifice 69 to cylinder 56. Orifice 69 controls the rate at which the piston of cylinder 56 extends or retracts. Excess flow, when orifree 69 is controlling the rate at which the piston of cylinder 56 extends, goes over the relief valve 33.

De-energizing coil 63 will remove holding force from plunger 53 and spring 71 will force plunger 53 to position itself on seat 54 blocking passage 67 to passage 57. When coil 58 of solenoid valve 39 is de-energized, plunger 59 will move away from poppet 61 which moves away from seat 62 allowing the flow from pump 28 to go to sump 29. This puts valve 39 back into neutral position. In this neutral position, reel lift cylinder 56 goes into hold position and the spring 71 holds the plunger 53 on seat 54 of solenoid valve 41 which acts as a lock valve.

To retract cylinder 56, solenoid valve coil 63 of solenoid valve 41 is energized by depressing switch 22 (FIG. 2) resulting in plunger 53 (FIG. 3) being pulled away from seat 54 against spring 71. Plunger 53 moves away from seat 54 allowing hydraulic fluid from cylinder 56 to go to cavity 57. Oil flows from cavity 57 through

passages

31, 48, 49 and S1 and line 52 back to sump 29. As soon as coil 63 of solenoid valve 41 is deenergized, spring 71 forces plunger 53 on seat 54 blocking flow from cylinder 56 to cavity 57.

The steps described above illustrate complete operation of the reel lift section of the valve. The valve also has a traction drive section and a reel speed section which are identical to the reel lift operation and a repeat of describing such operation is not deemed necessary excepting that the reel speed function is carried on at 600 psi maximum pressure whereas the other functions, including the reel lift and traction drive, are at 2,000 psi. In the reel speed control operation,

solenoid valves

38 and 46 are arranged as shown in FIG. 3. Operation of this valve section is identical to the operation of the reel lift cylinder section in that when

solenoids

38 and 39 are energized to extend the reel speed cylinder 72, hydraulic fluid flows from pump 28 through valve 38, cavity 73 and line 74 to cylinder 72. Pressure in cavity 73 is sensed by solenoid valve 46 functioning as a relief valve and which regulates the pressure in cavity 73 at 600 psi. However, this does not affect the system pressure which is regulated by a relief valve 33 at 2,000 psi. During operation of functions other than reel speed, solenoid valve 38 isolates cavity 73 from passage 31. If the pressure in cavity 73 exceeds 600 psi, plunger 75 retracts against spring 76 permitting flow of fluid to sump 29 maintaining pressure of 600 psi in cavity 73. v

The auger swing section has a double acting cylinder 77 and operation of the auger swing is accomplished by

solenoid valves

36, 37, 42 and 43.

Energizing

solenoid valves

39, 36 and 43 will cause hydraulic fluid to flow through valve 36 to the auger swing cylinder piston end 78. Fluid from rod end 79 of the cylinder 77 will flow through valve 43 back to sump 29 and the cylinder 77 will extend. As soon as

solenoid valves

39, 36 and 43 are de-energized, cylinder 77 will go into hold position and be held by solenoid valves, 36, 37, 42, and 43.

When

solenoid valves

39, 37 and 42 are energized,

hydraulic fluid moves from pump 28 through valve 37 to the auger swing cylinder rod end 79. Hydraulic fluid from the base end 78 goes to the sump 29 through solenoid valve 42 and cylinder 77 retracts. Cylinder 77 goes into the previously described hold position as soon as the solenoid valves are de-energized.

Similar sections as described above, could be added to valve body 27 by inserting'additional sets of valves arranged in the same way as the auger swing section.

FIG. 3 shows the valve body 27 connected in an open center system. Pump 28 supplies hydraulic fluid into valve body 27 at inlet port 47 and such hydraulic fluid flows through

passages

31, 48, 49, 51 and line 52 back to sump 29. Whenever normally open valve 39 is energized, pump flow is blocked from returning to sump 29 and pressure fluid becomes available to all sections of valve body 27.

Solenoid valves

41, 36, 37, 42 and 44 act as check valves and they isolate each section from the other. Any of the functions available in the valve housing 27 can be operated as previously described without affecting the rest of the functions.

In neutral,

solenoid valves

41, 42, 37 and 38 act as lock valves and hold the pressures in the respective cylinders. When these solenoid valves are energized, they act'as directional control valves and direct flow from the pump to the cylinder or vice-versa. Thus, both the functions of lock or check valve and that of directional control valve are accomplished by the unique arrangement shown in FIG. 3. Solenoid valve 44 forms the traction drive section and this section functions exactly as the reel lift section was described as functioning; namely: to extend traction drive cylinder 81, solenoid valve 44 is energized by raising switch 24 (FIG. 2); When coil 58 (FIG. 3) of solenoid valve 39 is energized, plunger 59 moves and seats on poppet 61 which in turn moves together with plunger 59 and seats on valve seat 62 closing the passage between 48 and 49. The flow of pump 28 is now blocked from the sump 29 and is available for any of the functions in the valve. When coil 82 of the solenoid valve 44 is energized, plunger 83 moves away from seat 84 allowing hydraulic fluid to flow from passage 31 through passage 86 to cavity 87. When pressure in cavity 87 exceeds cylinder pressure, such pressure fluid passes through

passages

86, 87 and orifice 88 to cylinder 81. Orifice 88 controls the rate at which cylinder 81 extends or retracts. Excess flow, when orifice 88 is controlling the rate at which cylinder 81 extends, goes over relief valve 33.

De-energizing coil 82 will remove the holding force from plunger 83 against the bias of spring 85 and spring 85 will force the plunger 83 to position on seat 84 blocking the passage from 86 to 87. When coil 58 of solenoid valve 39 is de-energized, plunger 59 will move away from poppet 61 which moves away from seat 62 allowing pump flow to go to sump 29. This puts the valve back into neutral position. In neutral, traction drive cylinder 81 goes into hold position and is held on poppet seat 84 of solenoid valve 44 which acts as a lock valve.

To retract cylinder 81, solenoid coil 82 is energized which pulls plunger 83 away from seat 84 against spring 85. Plunger 83 moves away from seat 84 allowing hydraulic fluid from cylinder 81 to go to cavity 87. I-Iydraulic fluid flows from cavity 87 through passages 86,

31, 48, 49, 51 and line 52 back to sump 29. As soon as coil 82 of solenoid valve 44 is de-energized, spring 85 forces plunger 83 on to seat 84 blocking flow from cylinder 81 to cavity 87 and valve 39 goes into neutral.

Referring to FIG. 2, each of the

switches

22, 23, 24 and 26 are shown to be of a double throw type. Each switch is provided with an upper connection 91 and a lower connection 92 leading to electrical power source 93 on combine 10. Switch 22 is provided with a lower lead 94 connected to the coil 63 of solenoid 41 so that by depressing switch 22 coil 63 is energized.

Switches

22, 23, 24 and 26 are also provided with an upper contact 96 which is connected to the coil 58 of solenoid 39. Switch 22 is also provided with an upper lead 97 connected to the coil 63 of solenoid 41 so that by moving switch 22 upwardly power is supplied to lines 96 and 97 for energizing

solenoids

39 and 41.

Switch 23 is provided with a lower contact 98 connected to the coil of solenoid 42 and the coil of solenoid 37 and switch 23 is also provided a lower contact 99 connected to contact 96 so that when switch 23 is

depressed solenoids

37, 39 and 42 are actuated for connecting the rod end 79 of cylinder 77 with line 31 and a source of hydraulic fluid and the piston end 78 of cylinder 77 is connected up with sump 29, respectively. Switch 23 is also provided with an upper contact 101 connected to the coils of

solenoid valves

36 and 43 so that when switch 23 is raised

valves

36, 39 and 42 are actuated, the rod end 79 of cylinder 77 is connected to sump 29 and the piston end 78 is connected to line 31 for receiving hydraulic fluid from pump 28.

Switch 24 is provided with lower contact 102 connected to the coil of solenoid valve 44 so that when switch 24 is depressed solenoid 44 is energized connecting cylinder 81 with line 31 for return to sump 29. Switch 24 is also provided with an upper contact 103 so that when switch 24 is raised

solenoids

39 and 44 are energized and hydraulic fluid flows from pump 28 to cylinder 81 extending same.

Switch 26 is provided with lower contact 104 connected to the coil of solenoid valve 46 so that when switch 26 is depressed solenoid 46 is actuated to connect cylinder 72 with sump 29. Switch 26 is also provided with an upper contact 106 so that when switch 26 is raised

solenoids

39 and 38 are energized and hydraulic fluid flows from pump 28 to cylinder 72 extending same.

The engine on a combine must so run as to maintain constant speed on the threshing and separating mechanisms. The ground speed, however, must be variable in minute increments as crop conditions vary. This speed variation is accomplished by a three-speed transmission driven through a variable diameter sheave arrangement. The effective diameter of the driven sheave is increased by a single acting hydraulic cylinder 81 and decreased by a spring in a conventional manner (not shown). To increase the combine speed, an electrical signal is sent from operators station 12 to

solenoid members

39 and 44 by raising switch 24. When solenoid member 39 closes it causes the normally open poppet 61 to close blocking the flow through valve 39. When this happens pressure builds up in the valve to approximately 2000 psi when relief valve 33 upstream relieves. Because solenoid 44 is also energized, it opens allowing hydraulic fluid to flow through orifice 88 to the traction drive cylinder 81. When the electrical signal from switch 24 is taken away, solenoid 44 closes trapping the hydraulic fluid in the traction drive cylinder 81 and maintaining that position of the variable diameter sheave arrangement and consequently, the speed of the vehicle. With no electrical signal, solenoid member 39 reopens and the hydraulic fluid is again free to circulate past solenoid 39 and deposit in sump 29. To slow down the traction speed, an electrical signal is sent to solenoid 44 by depressing switch 24 at the operators station 12, this causes an opening of solenoid valve 44 and allowing the spring load to force the hydraulic fluid out of cylinder 81 through valve 44 and through valve 39 where it moves to sump 29.

The reel height on the combine is maintained by a master-slave arrangement with only the master cylinder 56 being shown (FIG. 2). To raise the reel 18

solenoid members

39 and 41 are energized by pressing up on switch 22. This allows hydraulic fluid exerting a 2000 psi pressure to move past solenoid 41 to the reel lift cylinder 56. The reel 18 (P10. 1) is held in its desired position by solenoid 41 reclosing when the electrical signal is removed. When it is desired to lower reel 18 an electrical signal is transmitted to solenoid 41 by depressing switch 22 at the operators station. This results in the opening of solenoid 41 and permitting hydraulic fluid in ram 56 to exit through solenoid 41 into line 31 and through solenoid 39 to sump 29.

The unloading auger 14 is moved into operative bin unloading position by a double acting cylinder 77. To swing auger 14 into such unloading position switch 23 is actuated upwardly at the operators station 12. This energizes

solenoids

36, 39 and 43. The closing of solenoid 39 causes a pressure build-up in line 31 which causes hydraulic fluid to move through now open solenoid 36 to extend hydraulic cylinder 77. Hydraulic fluid from rod end 79 of cylinder 77 passes through now open solenoid valve 43 to be deposited in sump 29. When auger 14 has been swung to its operating position, it can be maintained in this position by interrupting the electrical signal from switch 23. Such interruption causes solenoid 39 to move to an open position connecting line 31 with sump 29 and causes

solenoids

36 and 43 to move to closed positions trapping the hydraulic fluid in both ends of cylinder 77. When it is desired to return auger 14 to its transport position alongside combine 10, switch 23 is

depressed actuating solenoids

37, 39 and 42. The closing of solenoid 39 causes a pressure build-up in line 31 which causes hydraulic fluid to move through now open solenoid 37 to retract hydraulic cylinder 77. Hydraulic fluid from piston end 78 of cylinder 77 passes through now open solenoid valve 42 to be deposited in sump 29. When auger 14 has been swung to its transport position, it can be maintained in this position by interrupting the electrical signal from switch 23. Such interruption causes solenoid 39 to move to an open position connecting line 31 with sump 29 and causes

solenoids

37 and 42 to move to closed positions trapping the hydraulic fluid in both ends of cylinder 77.

The speed of reel 18 is controlled by a conventional variable diameter sheave drive (not shown) which by its design is limited to 600 psi. This drive provides very little return force. This requirement has been met by the addition of a solenoid 46 which acts as a relief valve and unloading device. The poppet load orifice size relationship is such that the poppet will unseat and act as a direct acting relief valve at 600 psi. To increase the

reel speed solenoids

38 and 39 are energized by pressing up on switch 26. The closing of solenoid 39 results in a build-up of pressure in line 31 which pressurefluid pressurizes reel speed cylinder 72. This pressure is relieved to 600 psi by solenoid 46. To slow the reel down,

solenoids

39 and 46 are energized. Solenoid 39 closes stopping the flow of hydraulic fluid to sump 29. The magnetic load at solenoid 46 unseats the 600 psi relief and allows the reel speed return hydraulic fluid to flow through an empty line 107 to sump 29. This allows the system to operate at 600 psi with very low return pressures. The closing of solenoid valve 39 prevents dumping of fluid from the main passage 31 to sump by way of the common sump return passage, shown schematically in FIG. 2, thus allowing a low fluid return pressure for reel speed motor 72; however, it is of course possible to exhaust fluid from motor 72 by opening solenoid valve 46 without closing valve 39.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination in a self-propelled combine harvester having a control console positioned at an operators station, said combine being provided with a hydraulic system including a pump and a sump, the improvement comprising:

a double acting hydraulic cylinder,

a hydraulic manifold having a main passage connected in fluid receiving relation to said pump and in fluiddelivery relation to said sump and having a pair of supply passages operatively connecting opposite ends of said cylinder to said main passage, said manifold being positioned in remote relation to said console and proximate to said pump and sump to provide a minimum'passage of hydraulic fluid between said pump and sump when said hydraulic cylinder is not being operated,

a normally open solenoid valve mounted on said manifold and connected to said main passage, said normally open solenoid valve having an open position permitting hydraulic fluid to pass from said main passage to said sump and a closed position blocking fluid from flowing from said main passage to said sump,

a first pair of normally closed solenoid valves mounted on said manifold and connected respectively in controlling relation to said supply passages, said first pair of normally closed solenoid valves opening when energized to permit fluid flow in said supply passages, respectively, between said main passage to said cylinder, said first pair of normally closed solenoid valves being operative when not energized to prevent flow of fluid through said supply passages from said cylinder to said main passage,

a second pair of normally closed solenoid valves connected respectively to said supply passages and operable to control flow of fluid therefrom to said sump, said second pair of normally closed solenoid valves when opened being operative to pass fluid from said cylinder to said sump without it passing through said main passage, and

a plurality of switches positioned in said control console for controlling said solenoid valves and so connected to the latter whereby upon closing of selected switches on said console said normally open solenoid valve will be closed permitting buildup of hydraulic pressure in said main passage and upon subsequently opening one of said first pair of normally closed solenoid valves associated with one of said supply passages and opening the one of said second pair of normally closed solenoid valves associated with the other of said supply passages, fluid is delivered to one end of said cylinder and exhausted from the other.

2. In combination in a self-propelled combine harvester having a control console positioned at an operators station, said combine being provided with a hydraulic system including a pump, a sump and a plurality of hydraulically operated devices including a hydraulic motor, the improvement comprising:

a hydraulic manifold having a main passage connected in fluid receiving relation to said pump and in fluid delivery relation to said sump and a motor passage connected at one endto said main passage and having its other end connected to said motor,

a normally open solenoid valve mounted on said manifold connected in controlling relation to said main passage, said normally open solenoid valve having an open position permitting hydraulic fluid to pass from said pump to said sump by way of said main passage and a closed position blocking fluid from flowing from said pump to said sump by way of said main passage,

a first normally closed solenoid valve mounted on said manifold and connected in controlling relation to said motor passage, said first normally closed solenoid valve functioning when not energized as a check valve preventing return flow from said motor through said motor passage and opening when energized to permit fluid flow in said motor passage between said main passage and said motor,

a first relief valve operatively connected to the output side of said pump to establish a relatively high operating pressure for said main passage of said manifold when said normally open solenoid valve is closed, second normally closed solenoid valve interconnected between said motor passage and said sump and including a spring biased valve plunger operating as a second relief valve when said second valve is not energized, said second valve establishing a lower operating pressure for said motor passage than that established for said main passage by said first relief valve, and

a plurality of switches positioned in said control console for controlling said solenoid valves and connected to the latter whereby upon closing of selected switches on said console said first normally open solenoid valve will be closed permitting buildup of hydraulic pressure in said main passage and upon subsequently opening said normally closed solenoid valve pressurized hydraulic fluid is supplied through said normally closed solenoid valve and said motor passage to said one hydraulic motor causing said motor to be operated in one direction, and fluid being permitted to flow to sump from said motor by way of said motor passage without passing through said main passage when a selected switch in said control console is operated to energize said second normally closed solenoid valve thereby causing the latter to open.

Claims

1. In combination in a self-propelled combine harvester having a control console positioned at an operator''s station, said combine being provided with a hydraulic system including a pump and a sump, the improvement comprising: a double acting hydraulic cylinder, a hydraulic manifold having a main passage connected in fluid receiving relation to said pump and in fluid delivery relation to said sump and having a pair of supply passages operatively connecting opposite ends of said cylinder to said main passage, said manifold being positioned in remote relation to said console and proximate to said pump and sump to provide a minimum passage of hydraulic fluid between said pump and sump when said hydraulic cylinder is not being operated, a normally open solenoid valve mounted on said manifold and connected to said main passage, said normally open solenoid valve having An open position permitting hydraulic fluid to pass from said main passage to said sump and a closed position blocking fluid from flowing from said main passage to said sump, a first pair of normally closed solenoid valves mounted on said manifold and connected respectively in controlling relation to said supply passages, said first pair of normally closed solenoid valves opening when energized to permit fluid flow in said supply passages, respectively, between said main passage to said cylinder, said first pair of normally closed solenoid valves being operative when not energized to prevent flow of fluid through said supply passages from said cylinder to said main passage, a second pair of normally closed solenoid valves connected respectively to said supply passages and operable to control flow of fluid therefrom to said sump, said second pair of normally closed solenoid valves when opened being operative to pass fluid from said cylinder to said sump without it passing through said main passage, and a plurality of switches positioned in said control console for controlling said solenoid valves and so connected to the latter whereby upon closing of selected switches on said console said normally open solenoid valve will be closed permitting buildup of hydraulic pressure in said main passage and upon subsequently opening one of said first pair of normally closed solenoid valves associated with one of said supply passages and opening the one of said second pair of normally closed solenoid valves associated with the other of said supply passages, fluid is delivered to one end of said cylinder and exhausted from the other.

2. In combination in a self-propelled combine harvester having a control console positioned at an operator''s station, said combine being provided with a hydraulic system including a pump, a sump and a plurality of hydraulically operated devices including a hydraulic motor, the improvement comprising: a hydraulic manifold having a main passage connected in fluid receiving relation to said pump and in fluid delivery relation to said sump and a motor passage connected at one end to said main passage and having its other end connected to said motor, a normally open solenoid valve mounted on said manifold connected in controlling relation to said main passage, said normally open solenoid valve having an open position permitting hydraulic fluid to pass from said pump to said sump by way of said main passage and a closed position blocking fluid from flowing from said pump to said sump by way of said main passage, a first normally closed solenoid valve mounted on said manifold and connected in controlling relation to said motor passage, said first normally closed solenoid valve functioning when not energized as a check valve preventing return flow from said motor through said motor passage and opening when energized to permit fluid flow in said motor passage between said main passage and said motor, a first relief valve operatively connected to the output side of said pump to establish a relatively high operating pressure for said main passage of said manifold when said normally open solenoid valve is closed, a second normally closed solenoid valve interconnected between said motor passage and said sump and including a spring biased valve plunger operating as a second relief valve when said second valve is not energized, said second valve establishing a lower operating pressure for said motor passage than that established for said main passage by said first relief valve, and a plurality of switches positioned in said control console for controlling said solenoid valves and connected to the latter whereby upon closing of selected switches on said console said first normally open solenoid valve will be closed permitting buildup of hydraulic pressure in said main passage and upon subsequently opening said normally closed solenoid valve pressurized hydraulic fluid is supplied through said normally closed solenoiD valve and said motor passage to said one hydraulic motor causing said motor to be operated in one direction, and fluid being permitted to flow to sump from said motor by way of said motor passage without passing through said main passage when a selected switch in said control console is operated to energize said second normally closed solenoid valve thereby causing the latter to open.