US3420393A - Fluid motor position control - Google Patents

Description

Jan. 7, 1969 OMON 3,420,393

FLUID MOTOR POSITION CONTROL Filed April 19, 1967 s l INVENTOR. p

66126 L, Oman M45 0A3 SErrLE, 5970-154 052 flrr'v5. a. CiA/Cr,

Jan. 7, 1969 o o 3,420,393

FLUID MOTOR POSITION CONTROL Filed April 19, 1967 Sheet 2 of 5 I.\'\ 'ENTOR,

Gene L. 00201? B Y MLjON 55 74E) bkrcyaose QTT'} .5. 2669/6:

G. OMON 3,420,393

FLUID MOTOR POSITION CONTROL Jan. 7, 1969 Sheet 3 Filed April 19, 1967 I NVEN TOR. Gene L. Oman United States Patent 3,420,393 FLUID MOTOR POSITION CONTROL Gene L. Omen, Wauwatosa, Wis, assignor to J. 1. Case Company, Racine, Wis., a corporation of Wisconsin Filed Apr. 19, 1967, Ser. No. 631,959 US. Cl. 214-764 Int. Cl. E02f 3/74 9 Claims ABSTRACT OF THE DISCLOSURE Background of the invention The present invention relates generally to material handling equipment and more particularly to controls which automatically move the valve to its hold position when the implement controlling motor has reached a predetermined position.

In conventional earth moving equipment, such as bucket loaders, the machine generally consists of one or more lift arms pivotally carried on a vehicle, such as a tractor. A bucket is generally pivotally mounted on the free end of the lift arms and moved on the lift arms through a fluid motor or hydraulic actuator.

In normal operation the bucket is positioned in the dig position and is forced into a pile of material by motion of the tractor. The bucket is then pivoted or rolled back on the lift arms toward the tractor with suflicient force to break-out the mass of material into which the bucket has been shoved, so as to loosen the material from which surrounds it. The lift arms are then swung upwardly to raise the bucket above the ground and the tractor is driven to some other location. Upon reaching the location the bucket is swung to a dumping position where the contents are discharged, after which the tractor is driven back to the pile of material and the cycle is repeated.

The operation of the loader thus entails digging, breaking out, and dumping, all of which require swinging of the bucket with respect to the free ends of the lift arms. However, as is readily apparent, while the tractor is being moved from the dumping location to the pile of material, the operator must simultaneously move the vehicle to the pile of material and return the bucket to the digging position.

Various types of controls have proposed for automatically positioning the bucket on the lift arms of a vehicle while the vehicle is being returned to the pile of material. However, so far as applicant is aware, all of these devices require complicated mechanisms having elements which require extremely close tolerances and/or some types of mechanical or linkage connection between the movable bucket and the fixed valve controlling the flow of fluid to the motor which positions the bucket.

Summary of the invention.

Generally speaking, the present invention includes a first normally open limit switch carried by the fluid motor, a second normally open switch adjacent the valve, indexing means for maintaining the valve in operated position, electrical circuit means for interconnecting the switches and the indexing means and means responsive to relative movement of elements of the motor which automatically complete the circuit to the indexing means upon predeterice mined relative movement of the motor elements to allow the valve to close and position the relatively movable elements of the motor.

The primary object of the present invention is to provide electrical means for regulating a fluid supplying valve to position movable elements of a fluid motor in a predetermined position.

Another object is to provide an automatic positioner for a material handling implement which eliminates any mechanical connection between the movable and fixed elements of the implement.

A further object is to provide a simple control for positioning the bucket on its support automatically.

A still further object is to provide a simple electric control mechanism which is capable of positioning the bucket in a plurality of predetermined positions on its support.

Other objects and features of the invention will become apparent when considered in conjunction with the following specification and the accompanying drawings.

As shown on the drawings FIGURE 1 is a side elevation of the vehicle mounted implement or loader embodying the present invention;

FIGURE 2 is an enlarged fragmentary side elevation view of a tilt fluid motor having the control mechanism mounted thereon;

FIGURE 3 is a sectional view taken along lines 33 of FIGURE 2;

FIGURE 4 shows an enlarged fragmentary sectional elevation view of the control valve of the control mechanism;

FIGURE 5 is a schematic showing of the electrical circuitry for the control mechanism;

FIGURE 6 is a fragmentary side elevation of a modified form of switching mechanism for the fluid motor; and

FIGURE 7 is a fragmentary plan view of the fluid motor showing a further modification of the switching mechanism.

In the specification:

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and applications and of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for purpose of description and not of limitation.

FIGURE 1 of the drawings shows a conventional vehicle 10 having articulated sections 12 and 14. The rear section 12 is supported on a pair of Wheels 16 and encloses the power plant (not shown) for the vehicle.

The forward section 14 is likewise supported on a pair of wheels 18 and a pair of pivotally mounted lift arms 20 which are adapted to be raised and lowered on the section 14 through fluid motors or hydraulic actuators 22. A material handling implement or bucket assembly 24 is mounted on the free end of the lift arms 20.

The bucket assembly 24 includes a bucket 26 pivoted at 28 on the free end of the lift arms 22. The bucket 26 is pivoted on the lift arms 20 through a linkage including link 30, 32 and a fluid motor 34. One end of the link 30 is pivoted on the bucket while the second or opposite end is pivotally interconnected with the second link 32 which in turn is pivotally mounted on the lift arm 20.

Although only a single pivoting means including a cylinder 34 and links 30, 32 are shown, it is to be understood that this mechanism is duplicated on the opposite side of the vehicle. Likewise, a pair of lift arms 20 and actuating cylinders 22 as well as pairs of wheels 16, 18

form part of the tractor loader but are not shown since they do not form a specific part of the invention.

Fluid is selectively admitted to the opposite ends of the fluid motor 34 from a control valve 40 having fluid conduits (not shown) interconnecting the valve with the opposite ends of the fluid cylinder. A control lever 42 is disposed in the operators compartment 44 of the forward section of the vehicle for ready access by the operator.

As was noted above, during normal operation of the articulated loader, the bucket must be moved from the dumped position to the digging position while the vehicle is being returned to the pile of material. During this time it is highly desirable to allow the operator to direct all of his attention to manipulation of the vehicle.

Therefore, according to the invention, the digging position of the bucket is capable of being automatically achieved by a simple control device which allows the control valve to return to the neutral self-restored position after the bucket has reached a predetermined pivotal position on the lift arms or boom. This is accomplished by providing electrically actuated indexing means on the spool of the control valve and actuating the indexing means through an electrical circuit having a portion thereof carried by the tilt motor or cylinder which will automatically release the indexing means in response to predetermined pivotal movement of the bucket on the lift arms.

In the illustrated embodiment, the tilt control valve 40 (FIGURE 4) includes a valve spool 50 slidably received in the bore of the housing 52. The valve 40 is of the self-closing or the neutral self-restoring type which is accomplished through a self-restoring mechanism 54 associated with one end of the valve spool.

According to the invention, the valve spool 50 is provided with an extension 60 forming a part of the indexing means 62. The indexing means includes a housing 64 fitted on an extension 65 of the main valve housing 52. A detented sleeve 66 supports a detent 68 in the form of a plurality of balls. A detent holder 70 is slidably received in the housing 64 and is biased r urged into a position by a spring 71 where the detent or balls 68 are forced into engagement with a portion of the extension 60.

The detent holder has a plunger 72 secured to one end thereof. The plunger 72 is received in a solenoid coil 74 which has one terminal connected to the ignition switch (not shown) through a first wire 78. The second terminal is connected by a wire 80 to a first limit switch 82 located adjacent the control lever 42.

The limit switch 82 is connected in series with a second switch 84 by a wire 86. The switch 84 is supported on the cylinder of the fluid motor 34 and is suitably grounded to the vehicle through wire 88.

As clearly shown in FIGURE 4, the first switch 82 is secured to the housing 90 forming a part of the operators compartment of the vehicle. The switch includes actuating means in the form of an actuating finger 92 which is spring biased to the open position of the switch. The actuating means 92 is adapted to be moved to the actuated position by a pin 94 carried by the linkage 96 interconnecting the end of the valve spool 50 with the control lever 42.

The normally open switch 84 carried by the fluid motor 34 is preferably supported on the cylinder 100 of the fluid motor 34. For this purpose, the rod end of cylinder 100 has a pair of lugs 102 integrally formed with the end cap of the cylinder. The limit switch 84 is fixedly secured intermediate a pair of spaced plates 106 which are pivtally supported at one end between the lugs 102 through a pin 108. The opposite ends of the plates 106 rotatably support a roller 1.10 on a pin 112.

A recessed block 112 is supported intermediate the plates 106 and receives one end of a spring 114 with the opposite end of the spring being received in a recess or opening 116 formed in the cylinder end cap. The normally opened limit switch 84 has an actuating finger 118 which is in constant engagement with a recess formed on the end cap and is actuated in a manner to be described later.

The switch 84 is actuated through means carried by the fluid motor 34. In the illustrated embodiment of FIG- URES 2 and 3, the switch actuating means includes a control rod 120 pivoted at one end on a bracket .122 adjusta-bly secured to the piston rod 124 of the fluid motor 34. The opposite end of the control rod 120 is slidably received in a guide tube 126 supported at opposite ends on clamps 128 and 130 secured at spaced points to the cylinder 100. The control rod includes a pair of spaced recesses 132 and 134, for a purpose to be described later.

In the assembled position, the control rod is slidable in the guide tube 126 as the postion rod 124 is extended and retracted in the cylinder 100. The roller 110 is in constant engagement with the surface of the rod 120 and normally urges the plates 106 carrying limit switch 84 against the action of the spring 114 to move the actuating finger 118 to a position wherein the normally closed limit switch 84 is open. When the control rod 120 is moved to a position wherein the recess 132 or 134 is in alignment with the roller 110, the action of the spring 114 will urge the roller into the recess allowing the actuating finger to move to its free unrestrained position thereby closing the switch 84.

Operation The operation of the preferred embodiment can readily be understood by those skilled in the art. After the bucket has been moved to the raised position and the contents thereof have been dumped, the lever 42 is rotated clockwise to move the tilt spool 50 leftward as viewed in FIGURE 4, which will close switch 82 and will allow the the detent 68 to be received in the recess portion of the valve spool extension 60. The force of the spring 71 will be sufiicient to maintain the valve spool in the actuated position thereby directing fluid to the rod end of the cylinder causing the cylinder to retract and pivoting the bucket 26 counterclockwise on the boom arms 20. During this movement, the retraction of the piston rod 124 into the cylinder 100 will slide the control rod 120 into the guide tube 126 until the recess 132 is in alignment with the roller 110. The bias of the spring .114 will force the roller 110 into the recess 132 thereby allowing the actuating finger 118 of switch 84 to move away from the switch causing the switch to close. This will complete the circuit to the solenoid 74 which will slide the plunger 72 leftward as viewed in FIGURE 4 against the action of the spring 71 to allow the detent 68 to move out of the recess portion of the spool extension 60 and, through the operation of the centering means 54, the spool will be returned to the neutral position to discontinue flow of fluid to the fluid motor 34. Thus, the position of the bucket 26 on the lift arms 20 can automatically be positioned while the vehicle is being driven from the unloading position to the pile of material. Also, the critical angle of the bucket relative to the lift arms can repeatedly be obtained since the positioning is automatically accomplished and the retraction of the piston rod will always be stopped in the same position which is determined by the position of the recess 132 on the control rod 120.

Also, by locating the second switch 82 adjacent the valve spool 50 which is in the open condition when the valve spool is in the neutral position, the circuit to the solenoid will only be closed during the time required for the valve spool to move from the detented, operated position to the neutral position. This arrangement substantially increases the service life of the various parts.

Furthermore, by providing the second detent or recess 134 on the control rod 120, which corresponds to the fully rectracted position of the piston rod in the cylinder 100, the valve spool will automatically be moved to the neutral position when the piston rod has been fully retracted. This arrangement will prevent the valve spool from remaining in the operated position after the bucket has been pivoted to the fully retracted position. This will substantially increase the service life of the various parts caused by excessive pumping of fluid through the valve after the piston rod has been fully retracted.

A slightly modified form of the invention is shown in FIGURE 6. In the modified embodiment, a bracket 140 having a fixed arm 142 is secured to the end of the cylinder lllll. A link 144 is pivoted intermediate its ends on a bolt 146 secured to the arm 142. A switch 148, functionally identical to switch 84, is secured to the link 144 adjacent one end thereof with its actuating finger 149 in contacting engagement with a surface of the bracket 140.

The opposite end of the link 144 rotatably supports a roller 150 which is normally in contacting engagement with a control rod 152 and the roller is urged into contact with the surface of the rod 152 by a spring 154 interposed between the bracket 140 and the arm or link 144. One end of the control rod 152 is fixedly secured at 160 to the link 32 which is part of the bucket assembly 24. The control rod is guided along a predetermined path adjacent the link or arm 144 by being slidably received in an opening 162 formed in the bracket 140.

A pair of recesses 164, 166 are formed at spaced points on the control rod 152 and the distance between the spaced recesses and the end of the control rod connected to the link 32 is adjustable through suitable adjusting means 168.

The modified form of actuating means carried by the fluid motor 34, shown in FIGURE 6, is identical in operation to that described above with the switch 148 replacing switch 84 in FIGURE 5. Therefore, a detailed description thereof does not appear to be necessary. It should be noted that the position of the link 32 in FIG- URE 6 is in the fully rolled back position of the bucket on the boom.

A further modified form of switch mounting and actuating mechanism is shown in FIGURE 7. In the modified embodiment shown in FIGURE 7, a vertically ex tending support plate 180 is fixedly secured to the cylinder 160 by brackets 182 surrounding the cylinder. A limit switch 184, functionally identical to switch 84 is secured to the vertically disposed plate and has an actuator 186 which is rotatable in a horizontal plane and has a roller 188 carried on the free end thereof.

A control rod 190 has one end connected either to the link 32, forming a part of the bucket pivoting means, or directly to the piston rod 124 (neither of which are shown in FIGURE 7) and the opposite free end has a recess or abutment 192 thereon. The end of the control rod 190 having the recess 192 is guided along a predetermined path adjacent the switch 184 by suitable guide means 194. The roller 188 supported by actuating member 186 is normally urged to the position shown in FIGURE 7 and is adapted to be moved from the illustrated position by the abutment on the end of the control rod 190 to thereby close the switch.

The operation of the modified embodiment of FIG- URE 7 is identical to that shown in FIGURES 1 through 5. Thus, a predetermined sliding movement of the control rod 190 in the tubular member 192 will force the abutment 192 into engagement with the roller 188 and move the roller from the solid line position shown in FIGURE 7. This will actuate the switch 184 to complete the circuit to the solenoid 72 (FIGURE 4) to allow the control valve 40 to move to the neutral position.

As can readily be appreciate, the hydraulic actuating control of the invention provides a very simple inexpensive apparatus for automatically positioning the bucket with respect to the lift arms of a vehicle motor. Furthermore, the only interconnection between the movable parts (the lift arms) and the fixed parts (the forward section '16 and valve 40) is a single wire 86. This arrangement greatly simplifies the installation of the automatic positioning device. Of course, if desired, the actuating fingers or members of the limit switches in all embodiment could be placed in direct contact with the control rod to be moved between the neutral and actuated positions.

While three preferred embodiments of the invention have been shown and described, it will be understood that various changes and modifications may be made without departing from the spirit of the invention as defined by the following claims.

I claim:

1. An automatic positioning device for a fluid operated ram having relatively movable elements with a neutral self-restoring control valve movable between neutral and operated positions for directing fluid to said ram to provide relative movement of said elements, the device comprising a first switch adjacent said valve, means actuating said switch when said valve is moved to the operated position, retaining means carried by said valve for maintaining said valve in the operated position, a second switch carried by said one of said elements, electrical circuit means connecting said switches to said retaining means and means responsive to relative movement of said elements for actuating said second switch to complete said circuit to said retaining means to allow said valve to move to the neutral self-restoring position, said last means including a control rod guided along a path adjacent said ram and said second switch including an actuating member normally urged to a first position disposed in the path of said rod and movable to a second position to actuate said switch whereby a predetermined movement of said control rod will move said actuating member between first and second positions to complete said circuit.

2. A positioning device as defined in claim 1, in which said first switch actuating means includes means for opening said circuit when said valve is restored to neutral whereby said circuit is completed only while said valve moves from operated to neutral position.

3. In a loader having an implement movable on a vehicle, a fluid motor having movable elements for moving said implement on said vehicle and a self-closing valve movable between neutral and operated positions for controlling the flow of fluid to said motor, the improvement comprising indexing means for maintaining said valve in operated condition to cause movement of said implement on said vehicle, an electric circuit connected to said indexing means and including a first switch adjacent said valve, actuating means closing said switch when said valve is moved to an operated position, a second switch adjacent said motor, pivoted means supporting said switch and movable between first and second positions, and means responsive to movement of said implement for pivoting said pivoted means between said positions actuating said second switch and completing said circuit to release said indexing means and position said implement on the vehicle. 4. A loader as defined in claim 3, in which said actuating means for said first switch includes means for opening said switch when said valve is in the neutral position whereby said circuit is completed only while said valve is moved between operated and neutral positions.

5. A loader as defined in claim 3 in which said last means includes a control rod carried by one of said elements and having a recess thereon with means for guiding said rod along a predetermined path adjacent said motor and said pivoted means includes an arm movable between first and second positions with said second switch carried by said arm, a member carried by said arm and resilient means urging said member into contact with said rod, whereby alignment of said member and said recess will move said arm between the first and second positions closing said switch and completing the circuit to said indexing means.

6. A loader as defined in claim 5, wherein said control rod includes means defining a second recess spaced from said first recess to define a second position of said implement on said vehicle.

7. A loader as defined in claim 3, in which said last means includes a control rod secured to one of said elements and guided along a path adjacent the other of said elements and said second switch includes an actuating member movable from an inoperative position disposed in said path to an operative position out of said path whereby a predetermined movement of the control rod will move the second switch to the second position completing the circuit to said indexing means.

8. In a vehicle having an implement pivotally carried on a boom movable on said vehicle, a fluid motor connected to said implement for pivoting said implement on said boom, a valve selectively manually operable from a neutral self-restored position to first and second operated positions, fluid circuit means interconnecting said motor and valve, the improvement comprising locking means adjacent said valve for releasably maintaining said valve in an operated position, electrical circuit means connected to said locking means and including means carried by said motor responsive to pivotal movement of said implement for releasing said locking means and allowing said valve to return to the neutral position whereby to position the implement in a predetermined position on said boom, said last means including a control rod guided for movement along a predetermined path adjacent said ram, a supportin g plate pivotally mounted on said ram with said second switch carried by said plate, contacting means carried adjacent one end of said plate, resilient means urging said contacting means into engagement with said control rod, and means defining a recess on said control rod whereby, when said recess and said contacting means are aligned, the plate will be pivoted by said resilient means to move said second switch from a neutral position to an actuated position.

9. An automatic positioning device for a fluid operated ram having relatively movable elements with a neutral self-restoring control valve movable between neutral and operated positions for directing fluid to said ram to provide relative movement of said elements, the device comprising a first switch adjacent said valve, means actuating said switch when said valve is moved to the operated position, retaining means carried by said valve for maintaining said valve in the operated position, a second switch carried by said one of said elements, electrical circuit means connecting said switches to said retaining means and means responsive to relative movement of said elements for actuating said second switch to complete said circuit to said retaining means to allow said valve to move to the neutral self-restored position, said last means including a control rod guided for movement along a predetermined path adjacent said ram, a supporting plate pivotally mounted on said ram with said second switch carried by said plate, contacting means carried adjacent one end of said plate, resilient means urging said contacting means into engagement with said control rod, and means defining a recess on said control rod whereby, when said recess and said contacting means are aligned, the plate will be pivoted by said resilient means to move said second switch from a neutral position to an actuated position.

References Cited UNITED STATES PATENTS 2,331,108 10/1943 Ganahl 9l358 X 2,754,986 7/1956 Ferro 214-764 3,187,913 6/1965 Strader et al. 214-764 X HUGO O. SCHULZ, Primary Examiner.

US. Cl. X.R.

Images