US3720332A

US3720332A - Hydraulic systems

Info

Publication number: US3720332A
Application number: US00137881A
Authority: US
Inventors: L Molby
Original assignee: Tourneau Inc R Le
Current assignee: Keppel LeTourneau USA Inc
Priority date: 1971-04-27
Filing date: 1971-04-27
Publication date: 1973-03-13
Anticipated expiration: 1990-03-13

Abstract

IN A VEHICLE HAVING A PLURALITY OF WORK PERFORMING MEANS THAT ARE POWERED BY HYDRAULIC FLUID THE IMPROVEMENT CHARACTERIZED BY A PLURALITY OF INDIVIDUAL AND SEPARATELY OPERABLE HYDRAULIC SYSTEMS FOR OPERATING THE RESPECTIVE WORK PERFORMING MEANS, THE RESPECTIVE MOTORS AND PUMPS, PREFERABLY, BEING POSITIONED RELATIVELY CLOSELY ADJACENT THE WORK PERFORMING MEANS FOR WHICH THEY SUPPLY HYDRAULIC FLUID UNDER PRESSURE. ALSO DISCLOSED ARE (1) A TYPE OF CONTROL VALVE THAT IS OPERABLE TO START A MOTOR DRIVING A RESPECTIVE PUMP SIMULTANEOUSLY WITH DIRECTING THE HIGH PRESSURE HYDRAULIC FLUID OUTPUT OF THE PUMP TO OPERATE THE WORK PERFORMING MEANS, (2) OTHER SPECIFIC STRUCTURAL FEATURES, AND (3) ADVANTAGES.

D R A W I N G

Description

March 13, 1973 L. AJMOLBY v 3,720,332

HYDRAULIC SYSTEMS Filed April 27, 1971 I 2 Sheets-Sheet 1 if MAIN GENERATOR 15% l l l CONTROL /55 T T T VALVE CONTACTOR r759 /67 /645 26] 53 [6' 5. 9 n f] 125 147 49 g MAIN QONTROL PUMP MOTOR VALVE 1 59"" //Vl/E/V7'0R /wydfiWa/y I B) m ATTORNEYS March 13, 1973 1.. A. MOLBY 2 3 HYDRAULIC SYSTEMS Filed April 27, 1971 ZSheets-Sheet 2 United States Patent O 3,720,332 HYDRAULIC SYSTEMS Lloyd A. Molhy, Longview, Tern, assignor to R. G. Le Tourneau Inc., Longview, Tex. Filed Apr. 27, 1971, Ser. No. 137,881

Int. Cl. B66f 9/00 US. Cl. 214-140 14 Claims ABSTRACT OF THE DISCLOSURE Ina vehicle having a plurality of work performing means that are powered by hydraulic fluid the improvement characterized by a plurality of individual and separately operable hydraulic systems for operating the respective work performing means; the respective motors and pumps, preferably, being positioned relatively closely adjacent the work performing means for which they supply hydraulic fluid under pressure. Also disclosed are (l) a type of control valve that is operable to start a motor driving a respective pump simultaneously with directing the high pressure hydraulic fluid output of the pump to operate the work performing means; (2) other specific structural features; and (3) advantages.

BACKGROUND OF THE INVENTION (1) Field of the invention This invention relates to an improved hydraulic system for a vehicle having a plurality of work performing means that are powered by hydraulic fluid. More particularly, this invention relates to a plurality of separate and individual hydraulic systems for operating and powering respective ones of the plurality of work performing means on the vehicle.

(2) Description of the prior art The prior art has seen a wide variety of machines wherein a work function is performed by a hydraulically powered device. For example, in front end loaders or road grader type equipment there are a large number of work functions that are performed by hydraulic means. Respective ones of the work functions may involve a hydraulic ram which is attached to a work piece. The hydraulic ram is used to raise and lower a bucket or grader blade, and to obtain the desired degree of tilt and the respective positions thereof. It is thus apparent that numerous hydraulic rams, or cylinder-piston units, are required for each vehicle. It is also apparent that these hydraulic rams are disbursed and disposed at various locations on the vehicle.

It is conventional practice in a machine of the type above-mentioned to have a single hydraulic fluid reservoir and a single hydraulic pump for the entire machine. The hydraulic pump is normally driven directly by a transmission means that is powered by the vehicles internal combustion engine. The hydraulic pump is run continuously while the machine is running. Thus, hydraulic flow is constantly available to a manifold and selected valves on the manifold permit the hydraulic fluid to flow to selected hydraulic rams.

Vehicles such as those described hereinbefore are subject to several disadvantages. First, there are long runs of tubing, connections and pivot connections from the single pump location to the various hydraulic ram locations. Thismakes for a system that is expensive to install, diflicult to maintain and that requires care in operation to prevent severing one or more of the high pressure hoses in the cumbersome setup. Second, the single hydraulic pump must be running all the time that the machine is travelling and is generating maximum hydraulic flow 3,720,332 Patented Mar. 13, 1973 whether or not such flow is being used. Thus, even when the machine is merely travelling on roads to and from its destination, the maximum hydraulic fluid flow is still maintained. The excess horsepower that is employed in circulating the fluid is dissipated as waste heat and requires additional cooling. Third, in the event of failure of a hydraulic element such as the pump, the vehicle has had to be shut down to effect repairs in the field, instead of being able to drive the machine back to a central repaiar location where repair is facilitated and more satisfactorily carried out.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of an articulated front end loader vehicle employing one embodiment of this invention.

FIG. 2 is a schematic isometric view of an embodiment of this invention employing a plurality of separate hydraulic systems.

FIG. 3 is a schematic diagram of a control valve employed in one control means in a system in accordance with an embodiment of this invention.

FIG. 4 is a partial top plan view, partly schematic, illustrating an embodiment of this invention employing individual pumps and reservoirs in the hydraulic steering system.

FIG. 5 is a partial top plan view, partly schematic, illustrating an embodiment of this invention employing a separate hydraulic control system for the hydraulic rams raising the main beams.

FIG. 6 is a partial plan view, partly schematic, illustrating a hydraulic system for controlling the tilt of the bucket.

DESCRIPTION OF PREFERRED EMBODIMENTS It is a primary object of this invention to provide an improvement in hydraulically operable power systems for vehicles wherein hydraulic power is employed to operate a plurality of work performing means; the improved bydraulic system obviating the disadvantages of the prior art type vehicles.

Other objects of this invention will be apparent to those familiar with' the art when the following description is read in conjunction with the drawings.

Referring to FIG. 1, the present invention is shown incorporated in an articulated front end loader type vehicle 11 having a front section 13 and a rear section 15. The front section 13 has a pair of front wheels 17. The rear section 15 has a pair of rear wheels 19. The front and rear sections 13 and 15 are pivotally connected via pivot connection 21 for horizontal steering movement relative to one another about a substantially vertical steering axis 23. Specifically, a hydraulic ram, comprising a cylinder, piston and shaft arrangement, is connected to the front and rear sections on one or both sides of the pivot connection and effects the desired degree of steering via a steering connection 25 in response to the steering means in the operators console. The steering connection 25 is disposed laterally from the pivot connection 21 for a desired moment arm over which the steering force can be applied. A steering system such as described in my copending application Ser. No. 137,936, entitled Two Speed Steering System, filed Apr. 27, 1971, provides an improved steering system for the articulated vehicle 11. The hydraulic system, with its plurality of pumps for supplying hydraulic fluid under pressure will be described in more detail with regard to FIG. 4 hereinafter. It should be borne in mind, however, that the hydraulic steering system is one of the plurality of work performing means on the vehicle 11 that are powered by hydraulic fluid.

The vehicle 11 also carries hydraulic pumps 27 and 29 disposed closely adjacent to the

hydraulic rams

31 and 33 for which they supply hydraulic fluid at an elevated pressure. Disposed closely adjacent and connected with the respective pumps 27 and 29 are motors 35 and 37, as well as the control valves and the reservoir (not shown in FIG. 1).

For clarity in explanation and understanding, a simple schematic isometric is illustrated in FIG. 2 showing the operation of the hydraulic rams raising and lowering the arms carrying the bucket and the hydraulic rams controlling the angle of tilt by way of the bell crank linkage arrangement. Referring to FIG. 2, the bucket 41 is carried on main beams, or arms, 43 that are pivotally mounted by way of a suitable pivot shaft 45 on the vehicle (not shown in FIG. 2). The main beams 43 are cutaway to show the hydraulic rams 33 for raising and lowering the main beams in response to high pressure hydraulic fluid suitably directed to either the piston end or the shaft end, respectively. Specifically, the hydraulic rams 33 are pivotally mounted by stub shaft 47 connecting one end with the vehicle and a second stub shaft 49 connecting the other end with the main beam 43. The hydraulic cylinder portion of the hydraulic ram 33 is connected at its piston end via conduit 51 with a main control valve 53. Similarly, the shaft end of the cylinder portion of the hydraulic ram 33 is connected via conduit 55 with the other side of the main control valve 53. The main control valve 53 may be operably positioned to route hydraulic fluid at elevated pressure into either conduit 51 for raising the main beam 43 or into conduit 5,5 for power lowering of the main beam 43. If desired, of course, the hydraulic fluid from the piston end may be routed back to a hydraulic reservoir and allow gravity to effect lowering of the bucket. Power lowering is advantageous, however, where tamping or the like is desired. The main control valve 53 is connected with a first pump 57 by way of conduit 59 and with a reservoir, or sump, 61 by way of suitable filter 63. The pump 57 is driven by a motor 65. The pump 57 is also connected with the sump 61 via a filter 67 and conduit 69. The pump 57 may be the same a pump 27.

The main control valve is hydraulically connected with a control valve 71 by way of conduit such as conduits 73-76. The control valve 71 is operably positioned by a suitable lever 79' and effects fluid positioning of the main control valve so as to direct the main stream of high pressure hydraulic fluid to the respective conduit 51 or 55.

The bucket 41 is tilted by movement of the bell crank 81 about its fulcrum shaft 83. Specifically, the hydraulic rams 31 are pivotally connected at their one end with the vehicle via suitable shafts 85 and at their other end with the bell crank via shafts 87. The bottom end of the bell crank is connected with the bucket via link 89, FIG. 1, so'as to effect tilting of the bucket in response to lengthening or shortening of the hydraulic ram 31. The cylinder portion of the hydraulic rams 31 has their piston ends connected with the main control valve 95 via conduit 91. Similarly, the cylinder portion of the hydraulic rams 31 have their shaft ends connected with the main control valve 95 via conduit 93.

The main control valve 95 is connected with a second hydraulic pump 97 via conduit 99 and with the sump 61 via suitable conduit and filter means such as filters 63 and 101. The pump 97 is powered by a motor 103 and is connected to the sump 61 via conduit 105, and filter 107. The main control valve 95 is fluidly connected with control valve 109 via conduits 111-114.

As illustrated, the

main control valves

53 and 95 have a common housing and a common return conduit, as well as a common sump 61. Similarly, the pumps 5,7 and 97 have a common sump 61. The common sump may be employed, since the low pressure suction conduits 69 and 105 are not as easily damaged as the high pressure conduits and can run from the common sump to the pumps. Ad vantages, however, individual sumps, or reservoirs, are employed and are disposed closely adjacent the pumps, as

4 will become apparent from FIGS. 4-6, which are described later hereinafter.

As illustrated in FIG. 2, the control levers 79 and 117 a are positioned closely adjacent each other to facilitate control of the height and the angle of tilt of the bucket by the operator. Such closely adjacent positioning is not so much a requisite when a linkage arrangement such as described in my co-pending patent application Ser. No. 835,464, entitled Front End Loader Type Vehicle, filed June 23, 1969 now Pat. No. 3,606,061, granted Sept. 20, 1971; since, as described therein, the front end loader has a self levelling feature in which the bucket is emplaced at its surface position with its bottom edge substantially horizontal from its top position with the bottom edge being at the full dump angle.

In operation, hydraulic fluid is supplied under pressure to the main control valves '53 and via respective conduits 59 and 99. For example, the

pumps

57 and 97 may have an output of about gallons per minute, respectively. The

main control valves

53 and 95 divert a small portion thereof; for example, about 26 gallons per minute; to the control valves 71 and 109'. The respective control valves 711 and 109, responsive to the position of the control levers 79' and 117, route a required amount of high pressure fluid back to the

main control valves

53 and 95 to suitably position them, diverting the remainder of the hydraulic fluid back through the return position of the main control valves into sump 61. For example, initially the bucket 41 may have its bottom edge levelled by extension of the hydraulic ram 31. In such an event, the main control valve 95 is positioned to route high pressure hydraulic fluid via conduit 91 to the piston ends of the hydraulic rams 31, extending the respective shafts and effecting the desired levelling of the bottom of the bucket 41. Low pressure fluid from the shaft ends of the hydraulic rams 31 is returned through conduit 93 and through the low pressure fluid passageway of the main control valve 95 to the sump 61. Once a desired load is obtained in the bucket 41, the lever 1 17 is operated in the reverse direction to effect retraction of the hydraulic rams 31 and the desired tilt back of the bucket 41 to carry the load to its top position with minimal spilling. The lever 79 is operated to raise the bucket to its top position for dumping the load into a suitable receptacle such as a dump truck or the like. A portion of the diverted high pressure fluid is sent to position the main control valve 53 to direct high pressure hydraulic fluid into conduit '51 and thence into the piston ends of the hydraulic rams 33. Consequently, the bucket ends of the main beams 43 are raised about their pivot shafts 45 to effect the desired height of the bucket 41. At this point, the control lever 117 is operated to dump the bucket 41. Specifically, the lever 117 positions the control valve and ultimately effects a positioning of the main control valve 95 to direct high pressure hydraulic fluid into conduit 93 to retract the shaft and move the bucket 41 into its dump position. Thereafter, the control lever 79 is positioned in the direction opposite to which it was initially positioned to route high pressure hydraulic fluid into the conduit 55 and effect controlled, powered lowering of the bucket 41. As indicated hereinbefore, the low pressure hydraulic fluid from the hydraulic rams is vented through the respective return conduits to the sump 61.

Advantageously, the motors 65 and 103 are not operating during the road travel of the vehicle 11 when the bucket 41 is moved to its road travel position, such as its upper position where there is a minimum of obstruction to visibility. Obviously, the motors 65 and 103 may be controlled by a manual switch such as switch 119', FIG. 3. Such a manual switch may be preferred for long periods of use and nonuse. It is frequently advantageous to employ a switch means that is operatively associated with the control valve and its control lever to effect starting and stopping of the motor synchronously with direction of the hydraulic fluid through the control valve via the main control valve to its desired operation of the work performing means. Referring to FIG. 3, the control valve 123 and the main control valve 125 serve as a control means for controlling the work performing means such as one of the sets of hydraulic rams. The control valve 123 includes a plunger 127 that has a groove means 129 disposed peripherally therearound. On each side of the groove means 129 are disposed cam means 131. The plunger 127 is connected with a control lever 133. Any of the levers, linear or non-linear, that are available on the market may be employed as the control lever 133. Specifically, the control lever 133 is pivotally mounted for movement about a fulcrum shaft 135 and has its lower end connected with the plunger 127 via link 137. Accordingly, the plunger [127 is moved inwardly or outwardly in response to the appropriate direction of movement of the control lever 133. The control valve 123 is connected via conduit 13 9 with the main control valve 125, as a source of high pressure hydraulic fluid diverted by the main control valve. The control valve 123 is also connected with the main control valve via suitable conduit such as conduit 1 41 for effecting a respective position of the main control valve and thereby effecting the desired flow of high pressure hydraulic fluid to the work performing means. The main control valve may be biased toward neutral, but moved in a given direction against the biasing means by balanced hydraulic pressure or flow. The main control valve is conventional and need not be described in detail herein.

The control valve 123 also has a bypass conduit 143 for bypassing any unused high pressure fluid supplied by conduit 139. The bypass conduit 143 may be returned to the main control valve 125 through appropriate conduit or directly to a reservoir 145.

The main control valve 125 is connected with the discharge of pump 147 via conduit 149. The suction side of the pump 147 is connected with the reservoir 1 45 via conduit 151.

The pump 14'] is powered by motor 153. As illustrated, the motor 153 is a three-phase motor that is connected with the main generator 155 via contactor 157 and associated conductors such as conductor 159. The contactor 157 is operable to effect series connection of the motor 153 with the main generator 155 to energize the motor and start the pump 147 in response to closure of a control switch associated with the contactor 157. The control switch may be a manual switch 119, referenced hereinbefore, or it may be a switch such as switch 161 that is closed by movement of the plunger 127. As illustrated, the switch 161 has a switch plunger 163 that is depressed by a pivotally mounted lever 165 to effect a closed switch. The lever 165 has a roller 167 carried at its free end and engaging the recess means 129. Consequently, as the plunger 127 is moved inwardly or outwardly, the roller 16'7 cams up the cam means 131 contiguous the recess means 129 to close the switch and energize the motor 153 via the contactor 157. The switches 1-61 and 119 are connected in parallel and one or both may be employed as desired.

In operation, the operator of the vehicle will move control lever 133 in a predetermined direction to move the plunger 127 inwardly or outwardly. This movement closes the switch 161 and energizes the motor 153, starting pump 147. Hydraulic fluid is supplied to the main control valve 125 which diverts a small portion to the control valve 123. A portion of the high pressure hydraulic fluid is returned, the amount being proportional to movement of the plunger 127, through conduit 141 to efliect positioning of the main control valve 125. The remainder is bypassed to the reservoir, directly or indirectly, through conduit 143. The main control valve 125 effects the requisite flow of high pressure hydraulic fluid to the work performing means until the desired work is done; for example, the main beam 43 is elevated to the desired height. Thereafter, the control lever 133 is released and is returned via a spring (not shown) to its shut-off position, opening switch 161 6 through movement of the roller 167 into the recess means 129, and stopping pump 147. A liquid block is held on the work performing means through the appropriate positioning of the main control valve 125.

Movement of the control lever 133 in the opposite direction again cams the roller 167 up the opposite face of the cam means 131 contiguous the recess means 129 and starts the pump 147 as described hereinbefore. The control valve 123, however, positions the main control valve in the opposite direction; for example, by way of another conduit 169. In any event, the main control valve is positioned to effect a lowering of the main beam 43 and return of hydraulic fluid to the reservoir 145. Once the desired position, such as the surface position, of the bucket has been achieved, the control lever 133 is released and automatically returned to the shut-off position, stopping the pump and repositioning the control valve and the main control valve, as described hereinbefore. While additional reference numerals have been given the elements in FIG. 3, it is apparent that many of the elements are equivalent to recited elements in FIG. 2. For example, the pump 147 may be the same as pump 57, the control valve 123 may be employed as control valve 71 and the main control valve may be employed as the main control valve 53.

In FIGS. 4-6, discrete hydraulic systems are illustrated schematically with other systems cutaway for clarity of illustration.

Referring to FIG. 4, the steering system illustrated therein is described in detail in my co-pending application Ser. No. 137,936, referenced hereinbefore. The steering system need not be described in detail since the hereinbefore referenced application Ser. No. 137,936 can be referred to for such detailed explanation. A schematic operational description will serve to illustrate the use of a plurality of independently and separately operable hy draulic pumps to supply power for the respective elements. Specifically, steering wheel 171 operatively turns gerotor 173 to direct high pressure hydraulic fluid through one of the

conduits

175 or 177 for effecting a predetermined length L of hydraulic ram interconnection means 179. The gerotor 173 is supplied hydraulic fluid at elevated pressure from pump 181 via conduit 183. The pump 181 obtains its hydraulic fluid from reservoir 185. The gerotor 173 routes low pressure hydraulic fluid back to the reservoir 185 via conduit 187. Ordinarily, the pump 181 will run continuously to maintain a supply of hydraulic fluid under elevated pressure for use in steering the vehicle 11. The length L effects movement of the double bar link means 139. The double bar link means 189 then moves, first, a first memher 191 inwardly or outwardly to correspondingly effect a fluid flow via primary control valve 193 to the hydraulic ram

power steering servos

195 and 197. As the limit of travel of the first member 191 is reached, further movement of the double bar link :means 189 efiects movement of the second member 199 of the secondary control valve 201 for effecting a much greater flow of hydraulic fluid to the hydraulic ram

power steering servos

195 and 197. The primary and

secondary control valves

193 and 201 are connected in parallel to supply hydraulic fluid under pressure to the respective high pressure ends of the parallel connected hydraulic ram

power steering servos

195 and 197 for effecting the desired steer of the vehicle 11. Specifically, the primary and secondary control valves have their discharge aperture connected in parallel with conduit 203 for routing high pressure hydraulic fluid to the shaft end of the hydraulic ram power steering servo 195 and to the piston end of hydraulic ram power steering servo 197 for effecting a steer to the left. Conversely, the primary and

secondary control valves

193 and 201 have another discharge aperture connected in parallel with conduit 205 for routing high pressure hydraulic fluid to the shaft end of hydraulic ram power steering servo 197 and to the piston end of hydraulic ram power steering servo 195 for effecting a steer to the right.

Separate and independently

operable pumps

207 and 209 take suction from a reservoir 211 and supply high pressure hydraulic fluid to the respective primary control valve 193 and the secondary control valve 201. Either, or preferably both, pumps may be operated continuously if it is desired to have high pressure hydraulic fluid immediately available for the steering operation. On the other hand, either or both of the first and

second members

191 and 199 may have the same configuration as the plunger 127 of FIG. 3 and employed with a switch such as switch 161 to start the respective pump when a demand for slow and fast power steering is made, as by movement of a respective member in a predetermined direction. The pumps need not be operated in the same manner. For example, it is possible to operate only the primary pump 207 continuously and leave the secondary pump 209 idle until demand is made upon the secondary control valve 201. That is, the second member E199 will have a configuration and operative switch like plunger 127 of FIG. 3 so as to start the secondary pump 209 only upon demand for high speed steering.

In any event, the hydraulic fluid at elevated pressure is routed by either the primary control valve 1193 alone or both the primary and

secondary control valves

193 and 201 to effect the desired rate of steering via the hydraulic

power steering servos

195 and 197. As a degree of steer is effected, feedback from the steered section is effected. Specifically, the hydraulic ram interconnection member 179 is displaced a distance D from the substantially vertical steering axis 23 defined by the pivot connection, so that it returns the first and

second members

191 and 199 to the shut-off position to stop the flow of hydraulic fluid at the moment the signalled degree of steer has been effected. The transistion to the shut-01f point is effected smoothly, since the second member 199 and the secondary control valve 201 are returned to the shut-off position, first, to stop the large rate of flow of hydraulic fluid; and subsequently, the first member 191 and the primary control valve 193 are returned to the shut-01f position to stop the precisely controlled, low speed flow of hydraulic fluid to the

power steering servos

195 and 197.

As can be seen in FIG. 4, the reservoirs 185 and 21 1 are advantageously positioned close to their respective pumps '181, and 207 and 209.

FIG. 5 illustrates another embodiment of the invention in which the reservoir, as well as the control valve and pump, is emplaced closely adjacent the hydraulic ram for which hydraulic power is to be supplied. Therein, the main beams 43 carrying the bucket 41 are cut away to illustrate more clearly the hydraulic rams 33 employed to raise and lower the bucket. The vehicle frame (not shown) of the vehicle carries the motor driven pump 57. The pump 57 has its suction side connected with reservoir 213 via conduit 214 and has its discharge side connected with main control valve 53 via conduit 216 The main control valve 53 has one discharge aperture connected with the shaft end of the hydraulic rams 33 via conduit 215. The main control valve 53 has another discharge aperture connected with the piston end of the hydraulic rams 33 via conduit 217. The main control valve 53 has its return aperture connected with the reservoir 213 via conduit 219. The main control valve 53 may be positioned hydraulically by a control valve, as illustrated in FIG. 2, or it may be positioned by a suitable lineal member from a control console. Suitable lineal members comprise flexible members reciprocally encased within an armored housing, or linear rods extending from a control lever. In any event, the main control valve 53 is suitably positioned to direct the high pressure hydraulic fluid from pump 57 to the piston end of the hydraulic rams 33 for raising the main beams 43; or to the shaft end of the hydraulic rams 33 for lowering the main beams 43, as described hereinbefore. As illustrated, the pump, reservoir, and main control valve are located closely adjacent to the hydraulic rams they power so as to keep the high pressure fluid lines short for economical initial installation, easy maintainence and less care in operating the vehicle. The motor driving the pump may be controlled by manual switches or by switches that are closed or opened in response to movement of the control levers, or the like.

The operation of the system of FIG. 5 is the same as described with respect to FIG. 2 hereinbefore.

FIG. 6 illustrates schematically the hydraulic rams 31 effecting tilting of the bucket 41 via bell cranks 81, with the hydraulic pump and reservoir emplaced closely adjacent the hydraulic rams for which they supply hydraulic fluid at elevated pressure. Specifically, the vehicle frame (not shown) carries the motor driven hydraulic pump 97. Pump 97 has its suction side connected with the reservoir 221 via conduit 223. The pump 97 has its discharge side connected with the main control valve via conduit 225. The main control valve 95 has one of its discharge apertures connected with the shaft side of the hydraulic rams 31 via conduit 227.. The main control valve 95 has its other discharge port connected with the piston side of the hydraulic rams 31 via conduit 229. The main control valve 95 has its return port connected with reservoir 221 via conduit 231. The main control valve 95 may be hydraulically positionable by a control valve such as control valve -109, FIG. 2, or it may be positionable by any one of the other conventional positioning means enumerated with respect to the main control valve 53, FIG. 5. In any event, the main control valve 95 is operative todirect high pressure hydraulic fluid into either

conduit

227 or 229 toeffect the desired tilting of the bucket 41 via either retraction or extension of the hydraulic rams 31 and appropriate movement of the bell cranks 81 and links 89.

Operation of the hydraulic system of FIG. 6 is the same as described hereinbefore with respect to the components of FIG. 2.

The materials of construction ordinarily employed with the type of vehicle on which the systems are mounted will be employed in this invention.

This invention has been described with respect to having a single sump with which the respective pumps are connected via low pressure conduit; and the more advantageous structure in which separate reservoirs are disposed closely adjacent the pumps which are, in turn, disposed closely adjacent the respective hydraulically powered work performing means for which they supply hydraulic fluid at an elevated pressure.

Thus, it can be seen that the invention provides an improved vehicle having a plurality of discrete hydraulic systems that are separately and independently operable to provide the following advantages:

(1) There are no long runs of high pressure tubing, high pressure connections, and pivot connections to worry about in initial installation, in operation of the vehicle and in maintenance of the vehicle; consequently, there is less unsightly leakage;

(2) .By having separately controllable pumps, the vehicle can travel great distances without pumping large quantities of hydraulic fluid, as was formerly required when a single pump, or multiple pumps, having the total capacity needed, was connected to the prime mover, or internal combustion engine;

(3) By employing separate switch means, only the amount of oil that is necessary to do the job being signaled is employed instead of pumping enough to do a plurality of jobs; and

(4) In the event of failure of a hydraulic system, it is possible to turn off that particular hydraulic system and steer the vehicle back to a maintenance area to effect repairs in such a favorable environment, instead of having to shut down the vehicle and effect repairs in the field before being able to drive it.

Although the invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention.

What is claimed is:

1. In a vehicle having a plurality of work performing means that are powered by hydraulic fluid, the improvement comprising;

a plurality of independently and separately actuatable hydraulic fluid pumps;

a plurality of independently and separately actuatable motors each connected with its respective one of said hydraulic fluid pumps;

a plurality of independently and separately actuatable switch means for actuating said motors and pumps; and

a plurality of independently and separately operable control means connected by conduit means with the discharge side of respective of said pumps for controlling flow of fluid to and from said work performing means,

said control means including a control valve means having a plunger that is moved inwardly and outwardly to effect direction and quantity of flow of fluid, said plunger having groove means with cntiguous cam means, a respective switch means being disposed adjacent said plunger, said switch means having actuation means by which said switch means is responsively actuated into the on and off posi tions, said actuation means having roller means disposed in said groove means in the shut-off position and adjacent said respective cam means contiguous with said groove means whereby said switch means is turned on upon movement of said plunger in either direction to effect actuation of said motor and start its associated pump supplying fluid to said control valve means.

2. The vehicle of claim 1 wherein said control means are operably connected with a lever means which also effects operation of a respective said switch means to both initiate pumping by a respective pump and control the distribution of the pumped hydraulic fluid to the respective work performing means.

3. The vehicle of claim 1 wherein a respective manually operable switch means is provided for controlling said respective motor independently of said respective control means.

4. The vehicle of claim 1 wherein said respective pumps and motors are positioned on said vehicle adjacent said respective work performing means for keeping the high pressure hydraulic fluid flow conduit means short.

5. The vehicle of claim 4 wherein each said pump has its individual reservoir that is also positioned adjacent I said work performing means.

6. The vehicle of claim 1 wherein said control valve means includes a control valve and a main control valve; said control valve having said plunger, and being connected with said main control valve such that said main control valve is positioned in response to the output of said control valve with which it is connected.

7. The vehicle of claim 1 wherein said switch means is employed to operate a large current carrying contactor means intermediate a main generator and said motor, whereby said switch means and its associated conductors can be relatively small.

8. A vehicle adapted to perform a plurality of work performing functions comprising a frame, means for supporting said frame for movement,

5 means for driving said vehicle connected to said supporting means,

a plurality of work performing means on said frame adapted to be hydraulically actuated, a plurality of hydraulic pumps,

motors,

each of said pumps being connected for actuation by its respective one of said motors,

means connecting pumps to their respective work performing means to supply hydraulic fluid to said work performing means,

a generator connected to and driven by said vehicle driving means,

switch means for connecting said generator to said motors whereby said driving means may be operated without the motor load on said generator, and

a plurality of control means connected to control the flow of hydraulic fluid from said motors to their respective work performing means. 9. A vehicle according to claim 8 including means responsive to said control means for actuation of said switch means whereby when said control means is actuated said switch means starts its associated motor and pump responsive to said control means actuation to supply fluid thereto.

10. A vehicle according to claim 8 wherein said vehicle is a front end loader having a bucket supported by arms, and

said work performing means includes actuators connected to said bucket and said arms to raise and lower and tilt said bucket.

11. The vehicle of claim 8 wherein said control means are operably connected with a lever means which also effects operation of a respective said switch means to both initiate pumping by a respective pump and control the distribution of the pumped hydraulic fluid to the respective work performing means. 12. The vehicle of claim 8 wherein ently of said respective control means. 13. The vehicle of claim 8 wherein said respective pumps and motors are positioned on said vehicle adjacent said respective work performing means for keeping the high pressure hydraulic fiuid flow conduit means short. 14. The vehicle of claim 8 wherein each said pump has its individual reservoir that is also positioned adjacent said work performing means.

References Cited UNITED STATES PATENTS 65 EDGAR W. GEOGHEGAN, Primary Examiner U.S. Cl. X.R.

52 HE, DIGEST 2, 52 S a plurality of independent and separately actuatable a respective manually operable switch means is provided for controlling said respective motor independ-