US2789712A

US2789712A - Positioning system for tractor shoveles and the like

Info

Publication number: US2789712A
Application number: US371566A
Authority: US
Inventors: Bruce V Christensen
Original assignee: Clark Equipment Co
Current assignee: Doosan Bobcat North America Inc
Priority date: 1953-07-31
Filing date: 1953-07-31
Publication date: 1957-04-23
Anticipated expiration: 1974-04-23

Description

B. V. CHRISTENSEN April 23, 1957 POSITIONING SYSTEM FdR TRACTOR SHOVELS mp THE LIKE Filed July :51, 1953 2 Shets-Sheet 1 BY W (4 was" ATTY.

' A ril 23, 1957 a. v. CHRISTENSEN 2,789,712

- POSITIONING SYSTEM FOR TRACTOR SHOVELS AND THE LIKE Filed July 51, 1953 2 Sheets-Sheet 2 INVENTOR. BRUCE. V. CHRISTENSEN BY 7 mfwz - ATTY.

POSITIONING SYSTEM FOR TRACTOR SHOVELS AND THE LIKE Bruce V. Christensen, Berrien Springs, Mich, assignor to Clark Equipment Company, a corporation of Michigan Application July 31, 1953, Serial No. 371,566

10 Claims. (Cl. 214-140) This invention relates to positioning systems, and more particularly to positioning systems for use with mechanisms actuated by reciprocating hydraulic motors and the like.

My invention is described herein in a form suitable for use with shovel tilting mechanisms on vehicle mounted shovels; however, it is not limited to such use but may be used with equal facility for positioning other mechanisms.

Known tractor shovel vehicles have power actuated shovels arranged at the forward ends thereof. Such a shovel is pivotally mounted to the forward end of elevating arm members the latter of which are pivoted, at their rear ends, to the vehicle frame. The arm members are pivoted by suitable power actuated means for effecting elevation of the shovel.

A shovel of the general character to which I refer is generally employed in one of threerotative positions. The shovel is employed in one extreme position for dumping loads, in the other extreme position for transporting loads, and in an intermediate rotative position for engaging loads, such as loose material, by digging or scooping. Suitable power actuated means is provided for effecting movement of the shovel between its three rotative positions. No difiiculty is encountered in disposing the shovel in either the extreme clockwise position or the extreme counter-clockwise position since such positions correspond to the limits of movement of the power actuating means. However, it is quite difiicult to rapidly and accurately position the shovel in an intermediate scooping or load engaging position with known tilting mechanisms. Since the shovel is normally located forwardly and downwardly of the operators seat, it is difiicult, if not impossible, for the operator to properly position the shovel, by sight, at the correct scooping angle.

Various devices have been employed to aid an operator of the vehicle in positioning the shovel at the proper intermediate scooping angle. For example, aligning marks may be arranged on adjacent relatively movable portions of the mechanism that is employed for actuating the power tilting means, but this has not proved satisfactory due to the time required of the operator of the vehicle to carefully position the control lever relative to the aligning marks.

It is an object of my present invention to provide automatically operable means for facilitating the disposition of the shovel at the proper intermediate scooping position.

In the accomplishment of the foregoing object, I provide hydraulic actuating assembly means for effecting pivotal movement of the shovel. Suitable fluid lines are provided for directing fluid under pressure from a source of fluid pressure to the hydraulic actuating assembly means and fluid reservoir means is provided for receiving the fluid forced from the hydraulic actuating assembly means during actuation of the latter. The amount of fluid which is received by the fluid reservoir determines the extent of pivotal movement of the shovel; That is, as

the fluid reservoir becomes filled with fluid fromfthe hydraulic tilt assembly, no further fluid can be forced from the hydraulic assembly and thus actuation of the latter is stopped as Well as tilting of the shoveL, This arrangement provides for automatically positioning the shovel in an intermediate scooping position.

Should it become desirable to tilt the shovellbeyond the intermediate scooping position, selectively operable means, associated with the fluid reservoir, may be actuated for by-passing the latter to permit all the fluid'to be forced from the hydraulic actuating assembly means and returned to the source of fluid pressure. Such bypassing operation permits the hydraulic actuating assembly means to be actuated through its full range,,thus permitting the shovel to be tilted between one extrem position and the other extreme position, i I

Now, in order to acquaint those skilled in the art with the manner of constructing and using positioning mechanisms in accordance with the principles of my present invention, I shall describe in connection .withthe accompanying drawings a preferred embodiment of my inven- .tion. a

In the drawings: t

Figure 1 is a partial side elevational view of my present invention embodied with a tractor shovel; and

Figure 2 is a diagrammatic showing-of my present invention including a fluid circuit therefor.

Referring now to the drawings, there is'indicated gen-- erally by the reference numeral ill a tractor shovel vehicle, having suitable drive wheels 12 at the forward end thereof. Suitable prime mover and transmission means (not shown) are provided for driving the forward drive wheels 12. The vehicle HP is furtherprovided with an operators seat 14, forwardly of which is arranged a hand steering wheel 16 operatively connected through suitable linkage means with the rear'steering wheels (not shown) of the vehicle.

A shovel or scoop member 13 is arranged at the forward end of the vehicle 10 and is provided with rearwardly extending spaced apart bracket members 20.

which are pivotally mounted on a transverse shaft 21. The shaft 21 is carried at the forward end of rearwardly extending arm members 22, one arranged on eithertside of the truck 10. The arm members.22, at their rear ends, are secured to the ends of a shaft 23 journaled in the truck frame. Extending parallel to and above the arm members 22, at either side of the truck, are arm members 24, which are secured at their rear ends, to the ends of atransversehshaft 25 journaled in the truck frame. The arm members 22 and 24 constitute a parallelogram type linkage mechanism and are employed for a purpose to be more fully described hereinafter.

Power operated hydraulic actuating assemblies, ,indi-i cated generally by the reference numeral 32, one arranged on either side of thetruck lt), are provided for pivoting the arm members 24 whereby elevation of the shovel 18 maybe effected. Each hydraulic actuating assembly 32 comprises a cylinder 34 pivotally mountedat 35 to the truck frame, and a piston rod 36 pivotally mounted at 37 to the adjacent arm member 24. By selectively admitting fluid under pressure to the lower ends of the cylinders 34- of the hydraulic actuating assembly; means 32, the piston rods 36 may be distended for effecting counter-clockwise pivotal movement of the arm members 2ft about the pivotal mounting 25. Clockwise;

pivotal movement of the arm members 24 may be effected by bleeding fluid from the lower ends of the cylinders 34, which operation permits the piston rods 36 to move inwardly of the cylinders 34, under the force of Y gravity. H

Pivotally connected to the forward ends of the arm 2,789,712 Patented Apr. 23,

' members 24 about pivot pins 27, and also pivotally con- 1 nected to shaft 21, is a generally inverted U-shaped frame or yoke member 38. The cylinder 40 of hydraulic actuatin'g assembly means, indicated generally by the reference numeral 42, is pivotally mounted at 44to the upper bight. portion of the inverted U-shaped frame member 38. The hydraulic actuating assembly means 42 further comprises a piston rod 46 which is pivotally connected I at 48 to a flange member 50 suitably secured to the shovel matically, the shovel 18 in itsthree primary operating positions; the hydraulic actuating assembly means 42, and the hydraulic fluid circuit associated therewith which I shall now describe in detail.

The vehicle 10 is: provided with a source of fluid pressure which'may for example assume the form of a hydraulic fluid pump 52. The delivery or pressure side of the pump. -2 isconnected through a fluid line 54 with the "P011 '55 of a valve indicated generally by the reference numeral'56. A port 57 of the valve 56, in turn, is connected through a fluid line 58- with a sump tank indicated generally-at 60 and a port 59 at the lower end of the cylinder 40' of the hydraulic actuating assembly 42. The

intake side of 'the-pump 52 has connection with the sump tank 60 through a line 61. A check valve 62 is interposed in the fluid line 58. The port 64 of the valve 56 has connection through a fluid line 66'with a port 68 at the upper end of the cylinder 40 of the hydraulic actualting assembly means 42. The port 70 of the valve 56 has connection through a line 72 with, the port 74 of a second valve-76 and with theaforedescribe'd fluid line 58. A pair of

checkvalves

78 and 80 are interposed in the branches of the fluid line 72. The port 82 of. the valve 76 h-asconnection through afluid line 84 with the sump tank 60. Interposed in the. fluid line 84 is a check valve 86.

Arranged at a convenient locatioiiyon, the truck is a sh'ovel' 'tilt positioning control mechanism indicated gen- H erally' by the reference numeral 88. The mechanism comprises a cylind'er 90, closed at both, ends, which serves as 1a fluid'reservoir, andla free floating piston92 mounted for axial movement therein. Adjustable threaded stop means 94 is arranged. at the left end of the mechanism 88,

viewed in Figure 2, and may be adjusted for. varying the 'egztent of, travel of the istonm92.

Thepo'rt 9,6'at the left end offthe'. cylinder 96 communicatesith roug'h a fluid line 98 with'v the port 109 of the valve 76; The p'o'rt1'0'2' at the right end ofthe cylinder 90fconimunicat'es through a fluid line 104. with the port 106 of the valvev76.

T he valves 56. and 76 erectthe: conventional spooltype'which'are readily available on the market andtherefore is thought that a full showing and description thereofis not necessary for purposes of the present disclosure; The

valves

56 and 76 are provided with valve plungers 108and711 0 which ,have connection through suitable linkage respectively with

control levers

112 and 114 arranged closely adjacent-to the opera'tors seat of the vehicle/.

Assuming that the shovel 18 is in the position shown in Figure 1 and in solid lines in Figure 2, the industrial I truck may be driven forwardly for forcing the shovel intoa pile of material that is to be picked up After i p the truck 10, has beendriven forwardly andthe shovel 18' has been filled with material, the control lever 112 ad, jacentthe-drivers seatmay be actuated for causing the valve plunger 108 to be moved upwardly while the valve plunger 110 remains fixed. Such actuation of the valve plunger 108 permits fluid under pressure to flow from the pump 52 through the fluid line 54, the port 55, the valve 56, the valve port 64, the fluid line 66, and the port 68 into the upper end of the tilt cylinder 40 for causing the piston rod 46 to be moved outwardly of the cylinder 40. Downward movement of the piston rod 46 forces fluid from the bottomend. of the cylinder 40 through the fluid line 58, the check valve 80, the fluid line 72, the port 74, the valve 76, the port 82, the fluid line 84, and the check valve 86 to the sump tank 60. The

check valves

62 and 78 serve to prevent the flow of fluid therepast in, the direction in which the fluid is forced firom the lower end of the cylinder 40.

As a consequence of the distending of the piston rod 46, the flange member 50 and bucket or shovel 18 are pivoted counter-clockwise from the solid line scooping or digging position shown in Figure 2 to the dash line load carrying or transporting position. The shovel 18 may be maintained in the load transporting position shown in dash lines by returning the control lever 112 to a neutral position which effects the return of the valve plunger 108 to a ileutral or hold position. During movement of the shovel 18 from the solid line scooping position to the dash line load carrying position, it is to be noted that the tilt positioning control mechanism 88 remains unactuated due to the fact that the valve 110 is maintained in a neutral or hold position.

The shovel 18' may now be elevated by selectively admitting fluid under pressure to the lower ends of the cylinders 34 of the hydraulic actuating assembly means 32 for effecting counter-clockwise pivotal movement of the arm members 22 and 24 in a manner previously described hereinbefo're. After the shovel 18 has been elevated, the truck 10 may be driven to the location where the contentsof the shovel 18 are to be deposited.

The contents of the shovel 18 may be dumped or emptied by suitable actuation of the control levers so as to effect movement of the valve plunger 108 downwardly and the valve plunger 110 upwardly. After actuation of: the:

plungers

108 and 110 in such :a manner, fluid is permitted to flow from the pump 52 through line 54, port 55, valve 56, port'70, fluid line 72, check valve 78, 'andhence to port 74 of'the valve 76. From the port 74, the fluid under pressure flows through the valve 76, port 100,- fl uid line.98,and port 96 to the left end of the cylinder of the tilt positioningcontrolmechanism 88.. This flow of fluid under pressure causes the free floating piston 92 to be moved from the solid line position shown (at the left) in Figure 2 to the dash line position (at the right). The fluid which is displaced from thecylinder 90 is forced through port 102, fluid line 104, port 106, valve 76, port 82, fluid line 84,- and check valve 86, to the sump 60'.

Simultaneously, the force of'gravity urges the shovel18 to pivotclockwise from the dash line load carrying position to the double dot dash lihevdtimpposition. During such clockwise movement of'the shovel. 18, the piston rod 46 is moved upwardlywithih the cylinder 40 of the tilt mechanism 42"which creates a suction force at the lower end of the cylinder 40 for drawing oil therein from the sump tank 60 through theline 58 and the check valve 62. At the same time,,fiuid is forced from the upperend of the cylinder 40 through the port 68,,line 66,.port 64, valve 56; port'57 and line 58 to the sump tank 60,, Now, by returning the control valvesto their. neutral position the valve plunge'rs 108 and' I 10 arereturn'ed to their neutral or hold positions for maintaini'ngthe shovel 18 in the double dot dash line dump position.

If it is nowv desired to return the shovel 18 to the digging or scooping position shown in solid lines in.Figures 1 and 2, the control levers 1 12 and 1x4 need only be actuated for moving theya'lveplunger 108 up dlyand thevalvc plunger downwardly. Upon's actuation of the plungers 1'08 and 110, fluid under pressure will flow from upper end of the cylinder 40 for urging the piston rod '46 downwardly.

Downward movement of the piston rod 46 causes fluid within the lower end of the cylinder 40 to be forced through the port 59, fluid line 58,

check valve 80, port 74, valve 76, port 106, fluid line 104, and port 102, to the right end of the cylinder 90 of the tilt positioning control mechanism 88. This movement of the fluid under pressure into the cylinder 90 causes the free floating piston 92 to be moved from the right hand dash line position to the left hand'solid line position. Fluid which was contained in the left end of the cylinder 90 is forced through the port 96, fluid line 98, port 100, valve 76, port 82, fluid line 84, and check valve 86 to the sump tank 60.

At such time as the piston 92 reaches the solid line position shown in Figure 2, no further flow of fluid from the tilt cylinder 40 is permitted and thus downward movement of the piston rod 46 is stopped at a point intermediate of its extreme ends of normal travel. The position at which the piston rod 46 is stopped in movement depends upon the volume of the cylinder 90 and the posi tion of the adjusting means 94 of the tilt positioning control mechanism 88.

It will thus be seen that with the mechanism of my present inventionthe piston rod 46 may be automatically stopped in an intermediate position for disposing the shovel 18 in the solid line digging or scooping position. By returning the control levers to neutral positions, the

valve plungers

108 and 110 may be returned to their neutral or hold positions and the shovel 18 maintained in the solid line position shown in Figures 1 and 2. The above described cycle of operation may then be repeated. If desired, additional tilt positioning control mechanisms may be associated with the hydraulic tilt mechanism 42 under which circumstances the shovel 18 may be automatically positioned in any one of a plurality of intermediate tilt or rotative positions.

Now, while I have shown and described what I believe to be a preferred embodiment of my present invention, it will be understood by those skilled in the art that various modifications or rearrangements may be made therein without departing from the spirit and scope of my present invention.

I claim:

1. A positioning mechanism for a shovel carried by a vehicle and mounted for limited pivotal movement, comprising movable fluid means carried by the vehicle for efleeting pivotal movement of said shovel, said fluid means discharging fluid during pivotal movement of the said shovel, and reservoir means for receiving a portion of the fluid dischargeable from the said fluid means for automatically interrupting movement of the fluid means when said shovel reaches a predetermined pivotal position.

2. A positioning mechanism for a shovel carried by a vehicle and mounted for limited pivotal movement between two extreme positions, comprising power actuated fluid means carried by the vehicle for effecting pivotal movement of said shovel, said fluid means discharging fluid during pivotal movement of the said shovel, and selectively operable reservoir means for receiving a portion of the fluid dischargeable from the said fluid means for automatically interrupting actuation of the fluid means when said shovel reaches a predetermined intermediate pivotal position.

3. For use with a vehicle, the combination of a shovel, arm means pivoted at one end to the vehicle and at the other end to said shovel, first power actuated fluid means carried by the vehicle and having connection with said arm means for effecting pivotal movement of the latter whereby said shovel may be raised or lowered, second power actuated fluid means carried by said arm means for effecting pivotal movement of said shovel relative to said arm means, said second power actuated fluid means discharging fluid during pivotal movement of the said shovel relative to the said arm means, and reservoir means for receiving a portion of the fluid dischargeable from the said second power actuated fluid means for automatically interrupting actuation of the second power actuated fluid means when said shovel reaches a predetermined pivotal position relative to said arm means.

4. For use with a vehicle, the combination of a shovel carried by the vehicle and mounted for limited pivotal movement, movable fluid means carried by the vehicle for effecting pivotal movement of said shovel, said fluid means discharging fluid during pivotal movement o f'the said shovel, reservoir means for receiving a portion or the fluid'dischargeable by the said movable fluid means and automatically interrupting movement of said movable fluid means when said shovel reaches a predetermined pivotal position, and means associated with said'reservoir means for by-passing the latter in order that said shovel may be pivoted beyond said predetermined pivotal position.

5. For use with a vehicle, the combination of a shovel carried by the vehicle and mounted for limited pivotal movement, movable fluid means carried by the vehicle for effecting pivotal movement of said shovel, said movable fluid means discharging fluid during pivotal movement of the said shovel, tilt limiting reservoir means including multi-position valve means for receiving fluid discharged from the said movable fluid means and automatically interrupting movement of said movable fluid means when said valve means is in one position and said shovel reaches a predetermined pivotal position, and means associated with said valve means and operable when the latter is in another position for by-passing said tilt limiting reservoir means in order that said shovel may be pivoted beyond said predetermined pivotal position.

6. For use with a vehicle, the combination of a shovel carried by the vehicle and mounted for limited pivotal movement, hydraulic actuating assembly means carried by the vehicle for effecting pivotal movement of said shovel, a source of fluid pressure, means for directing fluid under pressure from said source of fluid pressure to one end of said hydraulic actuating means, the said hydraulic actuating means discharging fluid from the other end when pressure is applied and fluid admitted to the said one end, reservoir means for blocking the discharge of fluid from said other end of said hydraulic actuating means when said shovel reaches a predetermined pivotal position, and selectively operable means associated with said reservoir means for by-passing the latter to permit fluid to return from said hydraulic actuating assembly means to said source of fluid pressure in order that said shovel may be pivoted beyond said predetermined pivotal position.

7. For use with a vehicle, the combination of a shovel carried by the vehicle and mounted for limited pivotal movement, hydraulic actuating assembly means carried by the vehicle for effecting pivotal movement of said shovel, a source of fluid pressure, means for directing fluid under pressure from said source of fluid pressure to one end of said hydraulic actuating assembly means, means for receiving the fluid forced from the other end of said hydraulic actuating assembly means during actuation of the latter, and said last named means having a fluid capacity less than the fluid capacity of said hydraulic actuating assembly means whereby the extent of actuation of said hydraulic means is limited for automatically preventing tilting of said shovel beyond a predetermined rotative position.

8. For use with a vehicle, the combination of a shovel carried by the vehicle and mounted for limited pivotal movement, hydraulic actuating assembly means carried by the vehicle for effecting pivotal movement of said shovel, a source of fluid pressure, means for directing fluid under pressure from said source of fluid pressure to one end of said hydraulic actuating assembly means,

'11s a; receiving" rte fluid forced flora the ether hd hydraulic actuating assembly means duringv actuat n of th'e' latter, said fluid receiving means having a iiid capacity less than the fluid capacity of said hydraulic actuating assembly means whereby the extent of actuation of said hydraulic actuating assembly means is limited for automatically preventing tilting of said shovel beyond a predetermined rotative position, and selectively operable means associated with said fluid receiving means for bypassing latter to permit fluid forced from the other of said hydraulic actuating assembly means to flow to said 'sou rce of fluid pressure in order that said shovel may be pivoted beyond said predetermined rotative pennan v I For use with a vehicle, the combination of shovel carriedby the vehicle and mounted for limited pivotal. movement, hydraulic actuating assembly means carried by th e vehicle for eflecting pivotal movement of said shovel, a source of fluid pressure, means for directing fluid under pressure from said source of fluid pressure to one end tot' said hydraulic actuating assembly means, a tilt posit ioning control cylinder having a free floating piston therein for receiving the fluid forced from the other end o f said hydraulic actuating assembly means during actuation of the latter, said tilt positioning control cylinder having a fluid capacity less than the fluid capacity or said hydraulic actuating assembly means whereby the extentof actuation of said hydraulic actuating assembly means is limited for automatically preventing tilting of said shovel beyond a predetermined rotative position, and

selectively operable means associated with said tilt positioning control cylinder for by-passing the latter to permit fluid forced from the other end of said hydraulic actuating assembly means to flow to said source of fluid pressure in order that said shovel may be pivoted beyond saidpredetermined rotative position.

I0. use -it' ith a vehicle, the con'lbinationjof a shovel earned thevehicle and mounted for limited pivotal movement, hydraulic actuating assembly means carried by the vehicle for effecting pivotal movement of said shovel, a source of fluid pressure, means for directing fluid under pressurefrom said source of fluid pressure to one end of said hydraulic actuating. assembly means, tilt limiting means includinga cylinder having a free floating piston therein and multi-position valve means having one position for directing to said cylinder the fluid forced from the other end of said hydraulic actuating assembly meansduring actuation of the latter, said cylinder having a fluid capacity less than the fluid capacity of said by draulic actuating assembly means whereby the extent ot actuation of said hydraulic actuating assembly meansis limited for automatically preventing tilting of said shovel beyond a predetermined rotative position,- and means associated with said valve means and operable when the latter is in another position for b-y-passing saidtilt limiting means in order to permit fluid forced from the otherend of said hydraulic actuating assembly means to flow to said source of fluid pressure in order that said shovel may be pivoted beyond said predetermined rotative position.

References Cited in the fll'e of this patent UNITED STATES PATENTS 6 51,5 02 Fitzgerald June 1 2, 1900- 2,361,325 Silver Oct. 24, 1 944 v2,361,46 D gh r y 1, 194 4; 2;517 ,5s2 Lulla Aug. 8, 1 95 0 2, 53 1, 34Q Mathys Nov. 21,1950 2,613,822 Stanley ..w-a-Q Oct. 1-4, 1952