US3429471A

US3429471A - Bucket positioning kick-out controls for bucket loaders

Info

Publication number: US3429471A
Application number: US666292A
Authority: US
Inventors: Howard B Austin; John D Wait Jr
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1967-09-08
Filing date: 1967-09-08
Publication date: 1969-02-25
Anticipated expiration: 1986-02-25
Also published as: GB1212622A; BE720395A; DE1781196A1; FR1578685A

Description

Feb. 25, 1969 H. B. AUSTIN ET AL. 3,429,471

BUCKET POSITIONING KICK-OUT CONTROLS FOR BUCKET LOADERS Filed Sept. 8, 1967 Sheet of 4 INVENTORS HOWARD B. AUSTIN JOHN D. WAIT, JR.

ATTORNEYS Feb. 25, 1969 H. B. AUSTIN ET AL 3,429,471

BUCKET POSITIONING KICK-OUT CONTROLS FOR BUCKET LOADERS Sheet Z of 4 Filed Sept. 8. 1967 11-! 44 Ill/f; V I REL 42 43 v nzszvom J HEAD END or CYL.

ROD END OF CYL.

INVENTORS HOWARD B. AUSTIN JOHN D. WAIT, JR.

Feb. 25, 1969' H. B. AUSTIN ET AL 7 3,429,471

BUCKET POSITIONING KICK-OUT CONTROLS FOR BUCKET LOADERS Filed Sept. 8, 1967 Sheet 3 M4 RESERVOIR I N VEN TORS HOWARD B. AUSTIN JOHN D. WAIT JRL ATTORNEYS Feb. 25, 1969 H. B. AUSTIN ET AL 3,429,471

BUCKET POSITIONING KICK-OUT CONTROLS FOR BUCKET LOADERS Filed Sept. 8. 1967 Sheet 4 of 4 INVENTORS HOWARD B. AUSTIN JOHN D. WAIT, JR.

United States Patent Office 3,429,471 Patented Feb. 25, 1969 Filed Sept. 8, 1967, Ser. No. 666,292 U.S. Cl. 214-762 10 Claims Int. Cl. E02f 3/86, 3/87 ABSTRACT OF THE DISCLOSURE Automatic stops associated with a bucket pivotally supported by the lift arms of a bucket loader for positioning the bucket at four predetermined positions including dump, load dump height and ground or load level. The bucket loader has hydraulic jacks for controlling bucket elevation and additional jacks for controlling bucket tilt which take precedence over the elevating jacks. Two kick-outs return the elevating jack to a hold position when the bucket is at dump height or ground level. Two additional kick-outs return the tilting jacks to hold when the bucket is suitably positoned for dumping or filling. One of the kick-outs associated with each of the elevating jacks and the tilt jacks is collapsible to prevent their functioning during certain portions of the bucket loading operation.

Cross-reference to related U.S. patents U.S. Patent 3,211,310 entitled, Trip Mechanism for Automatically Positioning Vehicle Loaders, issued to R. G. McIndoo and assigned to the assignee of the present invention.

Background of the invention During operation of a bucket loader, its bucket must assume various tilted positions as well as various positions of elevation. The necessity of the operator to manually control the tilt and elevation positions of the bucket as Well as the operation of the bucket loader vehicle itself noticeably curtails the optimum operating efiiciency of the unit. Increasing the size of the bucket loader to provide a larger capacity not only increases these manipulative duties, but reduces the optimum operating efiiciency for other reasons as Well. For example, as the unit becomes larger it becomes more difficult for the operator to exactly judge the various positons at which motion of the bucket is to be halted. If contact of the buckets with mechanical stops or the ground is relied upon to limit bucket motion, contacting shock, particularly of large capacity buckets, is transmitted through the vehicle to result in undue mechanical wear to the loader as well as operator fatigue.

Various solutions have been employed in the prior art to at least partially overcome these problems. For example, in U.S. Patent 3,211,310, the bucket lift controls were provided with detents and with kick-outs disposed on the bucket lift arms to terminate operation of the bucket lift controls with the bucket at a selected dumping height or at ground level for loading. However, as will be made more apparent in the following description, such controls provide only a partial solution of the problem since the manipulative duties of the operator still include the Operation of the vehicle as well as complete control over the tilt position of the bucket.

The present invention overcomes the above problems by providing a bucket loader with a bucket positioning kick-out system which stops motion of the bucket preferably in four predetermined positions; namely, the dump, load, dump-height and ground level position.

The invention is described below with reference to the drawings wherein:

FIG. 1 is a side elevation of the forward portion of a bucket loader;

FIG. 2 is a schematic illustration of a control system for operating hydraulic lift jacks associated with the bucket lift arms and kick-outs which co-operate with the control to limit lift jack operation;

FIG, 3 is .a schematic illustration of a control system for operating hydraulic tilt jacks and kick-outs which cooperate with the control system to limit tilt jack operation;

FIG. 4 is a partial side view in elevation with parts in section of a master valve which functions together with the bucket tilt kick-out; and

FIG. 5 is a sectioned view of a collapsible kick-out assembly for limiting motion of the bucket lift-arms.

Referring now to FIG. 1, a bucket loader vehicle is illustrated as having a bucket assembly 12 pivotally connected thereto by means of a pair of forwardly extending lift-arms, one of which is indicated at 13. Tilt linkage for controlling the tilt position of the bucket is generally indicated at 14 and comprises a forward lever 16 pivotally connected to each lift arm at 17 and to the bucket by means of a link 18. A bell crank member 19 is pivotally connected at 21 to a rearward portion of each lift arm and has its lower end 22 pivotally connected to a link 23 which is also pivotally connected to the vehicle by a pin 25 adjacent a pivotal connection 24 between the lift arm and vehicle. A hydraulic cylinder 26 for controlling the title position of the bucket is pivotally connected between each forward tilt lever 16 and the respective bell crank member 19. A hydraulic cylinder 27 for controlling the elevated position of the bucket is positioned for interaction between the vehicle and each of the bucket lift arms. The bucket loader operator controls extension or detail below) tend toward a hold position to prevent movement or the bucket. However, both control systems are provided with detents to permit the operator to set the control system for a preferred motion of the bucket with the control system temporarily locked into its corresponding position by one of the detents. Referring again to FIG. I particularly, a master valve 31 is associated with the lift jack control system and interacts with

kickout cams

32 and 33 when the bucket is at ground level or dumping height respectively to cause the lift jack control system to be released from its detent position, whereupon the control system returns to its hold position and the bucket is prevented from further movement by means of the lift arms. The bucket 12 of FIG. 1 is shown at ground level in a loading position while the bucket illustrated in phantom at 34 is in a carry position at a suitable height to permit dumping. Similarly, a master valve 36 is associated with the tilt jack control system and interacts with

cam surfaces

37 and 38 when the bucket is tilted to its loading positon or dumping position respectively, to cause the tilt jack control system to be released from its detent position, whereupon the control system returns to its hold position and the bucket is prevented from further motion.

In the present invention, the lift and tilt controls are hydraulically interrelated such that the tilt control has operating precedence over the lift control. When the bucket is in its loading position at ground level it is necessary after loading for the operator to regulate both the tilt and lift controls to respectively rack-back the bucket to its carry position and to raise the bucket for dumping. To permit the operator to initially set both the tilt and lift control while preventing the kick-out function of the lift control during the preferential rack-back of the bucket to its carry position, the lift control kick-out cam 32 is collapsible to prevent its continued kick-out interaction with the master valve 31. Further, it is to be noted that when the operator racks-back the bucket to its carry position, the master valve 36 remains in kick-out relation with the kick-out cam surface 37 as the bucket is raised to dump height (note the phantom bucket at 34 in FIG. 1). To prevent continued kick-out relation between the master valve 36 and the cam 37 when the operator sets the tilt controls for bucket dumping, the master valve 36 also comprises a collapsible feature which will be discussed in more detail below.

Referring now to FIG. 2, the lift control system 28 is generally similar to the mechanism described in U.S. Patent No. 3,211,310. A control valve 41 receives hydraulic fluid through a conduit 44 by means of a pump 42 from a reservoir 43. A spool 46 disposed for longitudinal motion in the control valve 41 to control fluid flow through the control valve is centered in a hold position indicated by the letter H, by means of a spring centering mechanism 47, whereupon no fluid flow is permitted to the lift jacks and the bucket lift arms are prevented from moving. The spool also has a raise position R whereat fluid from the inlet conduit 44 passes through the control valve to a conduit 48 which communicates with the head ends of the lift jacks to cause extension of the jacks and lifting of the bucket. The spool also has a bucket lowering position L whereat fluid entering the control, valve from the conduit 44 is directed to a conduit 49 which communicates the fluid with the rod ends of the lift cylinders to cause retraction of the jacks and lowering of the bucket. The spool has a float position F whereat fluid in the control valve is in communication with both of the

conduits

48 and 49 so that the bucket and lift arms will descend by gravity. A bell crank lever 51 has one end 52 pivotally connected to the spool and is provided at its distal end with detent cam surfaces 53 and 54. A roller 56 mounted on a separate pivotal lever 57 normally rides on an end surface 58 of the bell crank lever, for example, when the spool is in its hold position. However, the lever 57 and the roller 56 are urged leftwardly by a spring 59, connected to the lever so that, when the spool is shifted leftwardly into its raise position, the roller engages the detent cam surface 54 and prevents the spool from being returned to its hold position. Similarly, as the spool is shifted rightwardly to its float position, the roller engages the detent cam surface 53 to similarly prevent the spool from returning to its hold position.

To provide the kick-out function which releases the bell crank lever 51 and the spool 46, from either detented position, a slave cylinder 61 is related therewith and is controlled by fluid communication from the master valve 31 through a fluid conduit 62. The cylinder 61 has a spool 63 reciprocably mounted therein with an extension 64 being pivotally secured to the lever 57. When the roller on the level 57 is in detent relation with either of the cam surfaces 53 and 54, the spool 63 is shifted leftwardly so that a space 66 between lands is in fluid communication with the conduit 62 from the master valve. The spool has a fluid passage 67 communicating the space 66 with an end chamber 68 between the end of the spool and the cylinder 61. Upon a kick-out function of the master valve (discussed in detail below), high pressure fluid is communicated to the slave valve through the conduit 62 so that the fluid enters the space 66. Flow of the fluid to drain through a conduit 69 is restricted at 71 and high pressure fluid is communicated through passage 67 into the end chamber 68 causing the spool and the lever 57 to be shifted rightwardly against the spring 59. The rightward motion of the lever 57 causes the roller 56 to be disengaged from either of the detent cam surfaces 53 or 54, and the control valve spool 46 is returned to its hold position by means of the spring assembly 47.

The master valve 31 which cooperates with either of the kick-out

cams

32 or 33 to provide the above noted kick-out function is also described in U.S. Patent 3,211,- 310. Briefly, high pressure hydraulic fluid is introduced to the master valve 31 by means of a conduit 72 which is in communication with the fluid conduit 48 for the lift cylinder. When a lever 73 on the master valve is rotated clockwise to the position illustrated in FIG. 2, by interaction of its roller 74 with either of the kick-out

cams

32 or 33, high pressure fluid from conduit 72 is permitted to pass through the master valve 31 into the conduit 62 to act upon the slave piston 61 and provide a kick-out function of the control valve as discussed above. To provide proper kick-out interaction between the valve and kick-out earns, the master valve is affixed to the loader structure. The earns 32 and 33 are mounted on the tilt linkage 23 by means of a bracket 70 such that both cams rotate about the valve during raising or lowering of the bucket on its lift arms. The

cams

32 and 33 are so positioned on the bracket that they contact the lever roller 74 of the master valve when the bucket is respectively at ground level in a loading position or at a suitable dump height in carry position. To insure a constant supply of high pressure fluid in the conduit 72, since such exists in conduit 48 only during raising of the bucket, an accumulator 75 is also disposed in communication with conduit 72 with a check valve 76 disposed across conduit 72 between the accumulator 75 and the conduit 48. Thus, high pressure fluid existing in conduit 48 is communicated into conduit 72 and accumulator 75 so the high fluid pressure is maintained in conduit 72 by the accumulator and prevented from draining to the conduit 48 by means of the check valve.

The necessity for the collapsible character of the kickout cam 32 is readily apparent from a brief review of the operating sequence of the bucket loader. During loading, the bucket is in the position illustrated in FIG. 1 and at the completion of loading it is necessary both to rackback the bucket to its carry position (illustrated at phantom 34) and to energize the lift jack 27 to raise the bucket to its dump height. With the bucket in that position, the roller 74 of the master valve is in kick-out relation with the cam 32. If the operator were to initially actuate both the tilt and lift control valves at the same time, the kick-out function of the master valve 31 would return the control valve spool 46 to its hold position during the preferential operation of the tilt jacks in racking back the bucket to its carry position. Thus, according to the present invention, the cam 32 is collapsible and upon engagement of the roller 74 therewith, the lever 73 will be rotated clockwise to provide kick-out fluid to the slave cylinder. However, the continued pressure of the roller 74 against the cam 32 causes a collapse or retraction of the cam to result in a counter clockwise rotation of the lever 73 and the flow of kick-out fluid to the slave cylinder 61 is terminated.

To describe this collapsing function of the cam 32, reference is had to FIG. 5 wherein the cam is illustrated in detail as a dash-pot assembly having a cylinder 81 with a piston 82 disposed for longitudinal motion therein. An extension 83 of the piston 82 has a cap 84 for kick-out engagement with the roller 74. The piston is urged outwardly by a spring 86. The cylinder has a passage 87 communicating through a conduit 89 with a fluid reservoir 88. The piston 82 has a passage 91 thereacross which contains a restricting orifice 92. In operation, as the roller 74 of the master valve comes in contact with the cap 84, the restricting orifice prevents rapid flow of hydraulic fluid from the spring chamber with the result that the master valve lever is rotated clockwise to result in the desired kick-out function. However, as the pressure of the roller 74 continues to be exerted against the cap,

hydraulic fluid in the cylinder spring chamber gradually flows through the restricting orifice permitting the piston 82, the extension 83 and the cap 84 to move downwardly into the cylinder 81. As the cap moves downwardly, the master valve lever 73 rotates counter clockwise to shut off fluid communication to the slave cylinder and prevent subsequent functioning of the kick-out. After the bucket has been raised from its ground position, the lever roller 74 is no longer aligned with the cap and the spring 86 causes outward movement of the piston cap, to interact with the roller 74 during a subsequent loading cycle to commence the desired kick-out.

Referring now to FIG. 3, the tilt jack control system 29 has a control valve 41, bell crank lever 51', lever 57 and slave cylinder 61' which are similar to the components numbered 41, 51, 57 and 61 in the lift jack control system 28 of FIG. 2. An important difference is to be noted in the spool 46' of the control valve which is similarly centered by a spring mechanism 47 at a hold position H where no fluid flow is permitted through the control valve to the tilt jacks thus preventing tilting motion of the bucket. The spool may be shifted leftwardly into a rack-back position indicated at R where high pressure fluid in the control valve from the conduit 44' is communicated to the rod end of the tilt jack 26 by means of the conduit 48'. The spool may also be shifted rightwardly to a dump position indicated by D where high pressure fluid in the control valve is communicated to the head end of the tilt jack 26 by means of the conduit 49'. When the spool is moved into the rack-back or dump position, the roller 56' on the lever 57 engages either the detent cam surface indicated at 54 or 53 respectively to temporarily hold the spool in its shifted position. The slave cylinder 61' is similar to the slave cylinder 61 of FIG. 2 and operates according to the actuating kick-out fluid in conduit 62 to shift the lever 57' rightwardly, thus disengaging the roller 56' from either of the detent carn surfaces and permitting the spool to return to its center hold position according to the spring 47'. High pressure hydraulic fluid is similarly assured at the master valve 36 by the fluid accumulator 75' and the check valve 76' in the conduit 72 which communicates the conduit 48 with the master valve 36.

However, the construction of the master valve 36 and its method of interacting with the kick-out

cam

37 and 38 varies from that described with reference to the lift control system of FIG. 2. As in FIG. 4, the master valve 36 consists of a housing 101 having a spool 102 reciprocably mounted therein and urged downwardly by means of a spring 103. The housing has an inlet port 104 communicating the conduit 72' with an annular recess 106 and an outlet port 107 communicating the conduit 62' with an annular recess 108. The spool 102 has a land 109 between a first annular slot 111 and a second annular slot 112. The spool 102 is actuated by a lever 113 secured to a shaft 114 which extends through the housing to have an external lever 116 secured thereto.

When the lever 116 is in the position illustrated in FIG. 4, the position of the spool 102 is controlled by the spring 103 to prevent communication of the high pressure fluid in 72' to the slave cylinder 61' by means of the conduit 62'. However, as the external lever 116 is rotated clockwise, it causes the lever 113 to drive the spool 102 upwardly against the spring 103, thus placing the conduits 72' and 62' in fluid communication through the master valve housing by means of the annular slot 112 on the spool, such that actuating kick-out fluid is provided to the slave cylinder 61' to permit its kick-out operation as described above.

To describe the cooperation of the master valve 36 with the kick-out

cams

37 and 38 which provides actuating kick-out fluid to the slave cylinder 61, having reference to both FIGS. 3 and 4, the master valve 36 is mounted upon one of the hydraulic jacks 26 (see FIG. 3). The external master valve lever 116 has a toggle 117 and with a roller 118 pivotally connected to a bifurcated area 119 of the lever 116. A leftward surface portion 121 of the upper end of the toggle is sharply angled to permit the toggle and roller to be pivoted leftwardly to the position illustrated in FIG. 4. However, the rightward surface portion 122 of the upper end of the toggle is generally normal to the toggle so that when the toggle and roller are pivoted rightwardly to the position illustrated in FIG. 3, the toggle forms an extension of the lever 116 whereupon the lever is actuated by contact with the kickout cams as described below. A spring 123 urges the toggle into its rightwardly pivoted position as illustrated in FIG. 3.

Continuing with reference to FIG. 3, the kick-out

cams

37 and 38 are disposed upon a tubular member 126, which is aflixed to the rod 127 of the tilt jack 26 by a suitable connection indicated at 128. To guide the tubular member 126 during its travel along with the tilt jack rod, it is in telescoping relation with a rod 129 which is aflixed to the tilt jack 26. Referring also to FIG. 1 for general reference, the kick-out cam 38 is disposed at a generally rearward position on the tubular member 126 so that a forward sloping surface 131 thereon comes into actuating relation with the roller 118 of the master valve lever 116 when the tilt jack 26 is extended to place the bucket in dump position. Similarly, the kick-out cam 37 is disposed generally forwardly upon the tubular member 126 such that a sloping surface 132 thereon comes into actuating relation with the roller of the master valve lever 116 when the tilt jack is retracted to position the bucket in its loading position illustrated in FIG. 1. However, as may be noted in FIG. 1, when the operator racks-back the bucket from its loading position to a carry position, the roller 118 rides forwardly upon the kick-out cam 37. With further reference to FIG. 1, it may be noted that when the bucket is racked back to a carry position, the roller 118 rests upon the kick-out cam 37 at a point just in front of a folding latch arrangement 133 which is disposed upon the kick-out cam 37. Due to the inter-connection of the tilt linkage between the bucket and the lift arms, the master valve lever roller remains in that position as the bucket is raised to its dump height in carry position as illustrated by the phantom postion 34 of FIG. 1. With the roller riding upon the cam surface, it is apparent that when the operator positions the tilt control valve 41' to its dump position, the master valve would then remain in its actuating position until the roller clears the cam 37, thus requiring the operator to hold the control valve spool 46' in its dumping position until the roller cleared the cam 37. To permit the operator to merely place the tilt control valve spool in its dumping position, with the spool autmatically held in that position until the bucket is dumped, the latch mechanism 133 (best illustrated in FIG. 4) has a pivotal latch 134 which trips the toggle 117 and causes it to rotate leftwardly against the spring 123 as its roller 118 passes over the latch. The toggle, in its leftward position illustrated in FIG. 4, permits the master valve lever 116 to rotate counter clockwise and the master valve terminates the flow of actuating kick-out fluid to the slave cylinder 61.

To prevent the latch 134 from interfering with the toggle position as its roller 118 advances leftwardly thereacross, the latch is pivotally connected to the cam 37 by a pin 136 and has a spring 137 disposed for interaction between the cam and the latch which tends to urge the latch rightwardly. Thus, as the roller advances leftwardly across the latch, the latch pivots leftwardly against the spring and into general alignment with the upper surface of the cam so that it does not interfere with the actuating position of the toggle 117 and the master valve lever 116. However, after the roller passes leftwardly across the latch, the latch is erected to its position shown in FIG. 4 by the spring to permit its subsequent tripping interaction with the toggle as described above.

The advantages of the present invention in reducing the manipulative duties of the bucket loader operator, are readily apparent from a consideration of the operating cycle of the bucket loader. For example, as the bucket approaches its loading position illustrated in FIG. 1, the "lift jack controls are detented in float position while the tilt jack controls are detented in rack-back position. When the bucket arrives at ground level, the lever 73 ;of the master valve of the lift control system interacts with the collapsible cam 32 and the master valve provides (actuating kick-out fluid to the slave cylinder 61 to release the control valve spool 46 from its detented float position 'and permit it to return to its hold position, thus terminating operation of the lift jacks. Similarly, when rackback of the tilt jacks places the bucket in its proper loading position, the lever 116 of the master valve 36 associated with the tilt control system engages the sloping surface 132 of the kick-out cam 37 and the master "valve provides actuating kick-out fluid to the slave cylinder 61 which releases the tilt control valve spool 46' from its rack-back position and permits it to return to its hold position to terminate further tilting operation. With the bucket in its loading position, the operator drives the vehicle forwardly to engage the bucket with tnaterial to be loaded. The operator then places the lift control valve spool in its raise position and the tilt control valve spool in its rack-back position. The collapsible nature of cam 32 prevents it from actuating the lift control master valve 31 thus permitting the lift control valve spool to remain in its raised position. The operator continues to hold the tilt control valve spool in its rack-back position until the bucket has assumed a proper carry position during which period the roller 118 on the tilt control master valve 36 rides leftwardly over the cam 37 and the latch 134. The operator releases the tilt control valve spool 46 with the bucket in its carry position, whereupon the lift jacks continue to elevate the bucket to its dumping height illustrated by phantom position 34 in FIG. 1. With the vehicle properly positioned for dumping, the operator positions the tilt control valve spool in its dump position whereupon the toggle 117 of the tilt control master valve is tripped by the erected latch 134, thus permitting the tilt control valve spool to remain in its dump position without further attention by the operator. As the kick-out cam 37 moves leftwardly away from the roller 118 of the tilt control master valve 36, the spring 123 causes the toggle to rotate rightwardly. Then when the bucket is in its dumping position, the toggle cooperates with the master valve lever 116 and the sloping surface of the kick-out cam 38 so that the master valve 36 provides actuating kick-out fluid to the slave cylinder 61' which releases the tilt control valve spool 46 from its dumping position and terminates operation of the tilt control jacks. At this point, the operator repositions the lift control valve spool in its float position and the tilt control valve spool in its rack-back position whereupon the bucket returns to its loading position at ground level as described above Without further attention from the operator and a new loading cycle may be commenced.

It is apparent from the above description that the manipulative duties of the operator are substantially reduced by the present invention. For example, when the operator desires to raise the bucket to its dumping height, to tilt the bucket forwardly for dumping, or to return the bucket to its loading position after dumping, it is only necessary for him to initially position the control .valve spool after which he may direct his attention to operation of the vehicle itself while the bucket motion is terminated at the proper position. Further, particularly when the bucket loader is a very large vehicle, the operator is not required to direct his attention to the bucket to ensure that its motion is terminated at the proper position.

It is further to be noted that the operator can retain full manual control over the tilt and lift controls by merely holding the control valve spools in a desired position whereupon the kick-outs will not function as described above.

We claim: 1. A bucket positioning kickout system for a bucket loader having .a bucket suspended by lift arms, tilt means for controlling the tilt position of the bucket and lift means for controlling bucket elevation through the lift ,arms, the tilt means and lift means tending toward hold positions to prevent tilt or lift motion of the bucket and having detent means for temporarily holding the tilt and lift control means in various operative positions, the combination comprising:

first and second tilt control kickout means arranged for interaction with the tilt control means when the bucket is properly tilted for loading and dumping respectively to release the tilt control means from a detented condition,

first and second lift control kickout means arranged for interaction with the lift control means when the bucket is at a proper elevation for loading and dumping respectively to release the lift control means from a detented condition, the tilt control means having operating preference over the lift control means, and

means for terminating effective interaction of the first lift control kickout means following initial interaction therebetween to prevent subsequent kickout interaction of the first lift control kickout means prior to subsequent motion of the bucket on its lift arms, said terminating means permitting similar interaction between the first lift control kickout means and the lift control means thereafter.

2. The combination of claim 1 wherein all of said kickout means may be overridden to permit completely manual positioning of the bucket by an operator of the loader.

3. The combination of claim 1 wherein the lift control kickout terminating means is an element in the first lift control kickout means which is collapsible following its interaction with the lift control means, the collapsible element being self restoring after subsequent motion of the bucket on its lift arms.

4. The combination of claim 3 wherein said first tilt control kickout remains in kickout interaction with said tilt control means during rack-back of the bucket from its loading position to its carry position and means are operatively associated with said first tilt control kickout to terminate its kickout interaction with said tilt control means upon forward tilting of the bucket from its carry position, said kickout terminating means being selfrestoring thereafter to permit kickout interaction between said first tilt control kickout and said tilt control means when the bucket subsequently is tilted to its loading position.

5. The combination of claim 4 wherein said lift control means comprises at least one hydraulic motor disposed in controlling relation to the bucket lift arms, a lift control valve operatively associated with said hydraulic motor for controlling its operation, said control valve tending to be in a hold position but operable at least into detent positions whereat said motor raises or permits lowering of the bucket on its lift arms, slave means associated with said control valve and operable according to kickout fluid provided therein to release said control valve from its detented positions and a master valve in fluid communication with said lift control slave means, said master valve operable to direct kickout fluid to said lift control means upon its interaction with said lift control kickout means.

6. The combination of claim 5 wherein said lift control master valve has a lever for controlling its operation and said first and second lift control kickout means are cams disposed on a loader member for motion relative to said lift control master valve lever according to motion of the bucket lift arms.

7. The combination of claim 6 wherein said first kickout cam is a dashpot assembly having a movable piston and a piston rod extending from said assembly for interacting contact with said master valve lever.

8. The combination of claim 4 wherein said tilt control means comprises at least one hydraulic motor asso ciated with the bucket by means of tilt linkage, a tilt control valve operatively associated with said tilt motor -for controlling its operation, said tilt control valve tending to be in a hold position while being operable into detent positions Whereat said tilt motor tilts the bucket forwardly and rearwardly by means of its tilt linkage, tilt control slave means associated with said tilt control valve and operable according to kickout fluid provided therein to release said tilt control valve from its detented positions and a tilt control master valve in fluid communication with said tilt control slave means, said master valve operable to direct kickout fluid to said tilt control slave means upon its interaction with said tilt control kickout means.

9. The combination of claim 8 where the tilt control motor is a hydraulic jack having a cylinder and rod and wherein said tilt control master valve has a rotatable lever for controlling its operation and is mounted on the jack cylinder and said tilt control kickouts are cams mounted on a member connected to the jack rod for motion therewith to move said kickout cams into interacting relation with said tilt control master valve lever for operation of said tilt control master valve.

10. The combination of claim 9 wherein said tilt control master valve lever has a pivotal toggle tending toward a centered position to cooperate with said tilt control lever and wherein said first tilt kickout cam has an elongated surface for interaction with said tilt control lever by means of its pivotal toggle and a folding latch disposed on its elongated surface which permits the toggle to ride thereover in its centered position as the bucket is tilted rearwardly from its loading position to its carry position but which trips said toggle from its centered position to prevent its cooperation with the tilt control lever in providing for kickout operation of the tilt control master valve as the bucket is tilted forwardly from its carry position.

References Cited UNITED STATES PATENTS 3,122,247 2/1964 Beck 214764 3,211,310 10/1965 McIndoo 214764 HUGO O. SCHULZ, Primary Examiner.

US. Cl. X.R.