US3219213A

US3219213A - Adjustable pitch dipper means

Info

Publication number: US3219213A
Application number: US251287A
Authority: US
Inventors: Learmont Tom
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-14
Filing date: 1963-01-14
Publication date: 1965-11-23
Anticipated expiration: 1982-11-23

Description

Nov. 23, 1965 T. LEARMONT ADJUSTABLE PITCH DIPPER MEANS 4 Sheets-Sheet 1 Filed Jan 14, 1965 INVENTOR. TOM LEARMONT ATTORNEY NOV. 23, 1965 LEARMQNT 3,219,213

ADJUSTABLE PITCH DIPPER MEANS Filed Jan. 14, 1963 4 Sheets-Sheet 2 FIG. 3

m @Ej i 55 FIG. 4

INVENTOR. TOM LEARMONT BY @MZ/Aw ATTORNEY Nov. 23, 1965 T. LEARMONT ADJUSTABLE PITCH DIPPER MEANS 4 Sheets-Sheet 3 Filed Jan. 14, 1965 FIG. 5

FIG. 6

INVENTOR. TOM LEARMONT ATTORNEY Nov. 23, 1965 LEARMONT 3,219,213

ADJUSTABLE PITCH DIPPER MEANS Filed Jan. 14, 1963 4 Sheets-Sheet 4 INVENTOR. TOM LEARMONT ATTORNEY United States Patent ()fiice 3,219,213 Patented Nov. 23, 1965 3,219,213 ADJUSTABLE PITCH DIPPER MEANS Torn Learmont, 8600 Glencoe Circle, Wauwatosa, Wis. Filed Jan. 14, 1963, Ser. No. 251,287 9 Claims. (Cl. 214-137) This invention relates to excavators and more particularly to power shovels having a dipper pivotally mounted on a dipper handle wherein said dipper is adjustably pivoted relative to said dipper handle.

Power shovels are used in the mining of coal, ore and the like. The dipper of such power shovels is filled or loaded by a forward thrust or crowding action of the dipper handle. The loaded dipper is hoisted over a truck, pile or the like where the dipper is emptied by allowing the door of the dipper to swing open.

In the design of dippers and the attachment thereof to dipper handles, consideration must be given to both the digging and the dumping efiiciency of the dippers. If the dipper is designed to be afiixed to the dipper handle without any provision for pivoting of the dipper with respect to the handle, it is possible that digging efiiciency will be obtained during the digging cycle of the power shovel, but the dipper will not be positioned for efficient discharge at the dumping portion of the cycle. For efiicient dumping of the dipper, the door should be allowed to swing clear to allow the loaded material to drop freely from the dipper, and the walls of the dipper should be substantially vertical so that the loaded material will drop freely from the dipper walls. As a power shovel is often required to work in a variety of locations, the shovel dipper does not always dump from the same distance from the ground. Therefore if the dipper is afiixed in a constant angular relation to the dipper handle, the walls of the dipper will not be vertical at a variety of dipper dump positions.

If, on the other hand, the dipper is designed to dump cleanly and the dipper is returned to digging position it is possible that the heel of the dipper will strike the ground before the dipper teeth engage the ground thereby causing a skidding of the dipper over the ground. Such skidding causes dipper heel wear.

If, to avoid heel wear, the dipper is affixed to the handle at an efiicient digging angle, the dipper is ordinarily in a tilted position at the dumping portion of the cycle which results in ineflicient discharge of material from the dipper and consequently the overall efliciency of the power shovel operation is reduced.

It is, therefore, advantageous to provide a dipper which is pivotally attached or hinged to the dipper handle whereby the pitch or angular relation of the dipper to the handle may be varied during the operation of the shovel. In this way, the dipper can have the desired angular relationship to the dipper handle for efficient digging, and by varying the pitch or angular relationship of the dipper, the dipper can be positioned for efficient discharge of the loaded material from the dipper.

Further, if the pitch of the dipper can be varied as the dipper teeth emerge from the ground, for example, by tilting so that the upper part of the dipper wall and teeth move toward the power shovel, the dipper can carry more material to the dumping portion of the cycle. Tilting of the dipper allows the loaded material to fall back into the dipper rather than spill outwardly past the dipper teeth. With proper tilting, less material is spilled as the dipper handle and dipper are swung to a discharge location. Such spillage from the dipper often results in strewn rocks over an area where rubber tired dump trucks travel thereby causing a hazardous driving condition, and a condition that results in excessive wear of the truck tires.

Thus, by providing a means for tilting the dipper, particularly a means controllable by a power shovel operator, the dipper may be tilted to the desired angle with respect to the dipper handle for the most efiicient digging and dumping. Such tilting control improves the overall efiiciency of the power shovel operation.

One embodiment of the invention provides a tilting means for the dipper whereby the dipper is tilted for efiicient discharge, and the dipper is repositioned to the proper tilt for efiicient digging by forcing the dipper against the ground at the beginning of the digging cycle.

In a second embodiment, a tilting means is provided for tilting the dipper for efficient discharge therefrom and wherein retraction of the dipper handle actuates a means for returning the dipper to the desired tilt for eflicient digging.

The third embodiment of the invention provides a mechanical linkage means for tilting the dipper to an efircient discharge position when the dipper door is opened, and wherein closure of the door repositi-ons the dipper to digging position.

It is therefore an object of this invention to provide a means for tilting a dipper with respect to a dipper handle to provide for efiicient discharge of material therefrom, and wherein said dipper is repositionable during the initiation of dipper digging action.

It is another object of this invention to provide a means for tilting the dipper while the dipper is returned to the digging portion of power shovel operation.

It is an object of this invention provide a tilting means for a dipper to avoid excessive heel wear on the dipper.

It is a further object of this invention to provide a tilting means under control of an operator for positioning a dipper in the dump portion of the cycle to allow an efiicient discharge of material from said dipper.

It is an object of this invention to provide dipper tilting means for improving the loading of the dipper and for preventing spillage from said dipper in the loaded condition.

It is another object of this invention to provide means for tilting the dipper when the dipper door is opened, and wherein movement of said dipper and the dipper handle toward digging position causes said door to close thereby returning said dipper to a predetermined digging tilt position with respect to said dipper handle.

It is a further object of the invention to provide a tilting means wherein said dipper is urged in a digging tilt position and wherein said dipper is tiltable to a discharge tilt position by actuation of said tilting means wherein pull on a hoist rope and a load in said dipper aid in positioning the dipper to discharge tilt position.

These and other objects of this invention may be found in the accompanying specification, claims and drawings, of which:

FIGURE 1 is a side elevation of a power shovel having tilting means for a dipper;

FIGURE 2 is an enlarged elevation of the dipper of FIGURE 1;

FIGURE 3 is an enlarged elevation of the tilting means of the dipper of FIGURE 1;

FIGURE 4 is a schematic diagram of the fluid circuit of the tilting means of FIGURE 3;

FIGURE 5 is an elevation view of a second embodiment of a tilting means for the dipper of FIGURE 2;

' FIGURE 6 is a schematic diagram of the fluid circuit of the tilting means of FIGURE 5;

FIGURE 7 is an elevation of a third embodiment of the invention; and I v FIGURE 8 is an elevation view of the dipper tilted by the tilting means of FIGURE 7.

Referring now to FIGURE 1, a power shovel 11 is shown having a frame 12 rotatably mounted on a crawler means 13. A'boom 14 is pivotally attached to the frame 12 as at pivot 15. The frame also carries a boom hoist winch 16, a dipper hoist winch 17, and a dipper thrusting winch 18.

Winch 16 manipulates boom suspension cables 19 to raise and lower boom 14. Winch 17 manipulates hoist ropes 20 to raise and lower dipper 21. The hoist ropes pass over boom point sheaves 43 to a pair of laterally spaced lugs'22 carried by the dipper 21.

The dipper 21 is hingeably mounted at pivot or hinge 40 on the outer end of the dipper handle 23. Handle 23 is slideably carried by a saddle block 24 which is pivotally carried on boom 14. Winch 18 manipulates thrust rope 25, attached to the rear end of dipper handle 23, and retracting rope 26, attached to the front end of handle '23; both of these ropes 25 and 26 are manipulated by Winch 18 and attached to handle 23 to provide for a thrust and retract movement of the dipper handle 23. 1 The dipper 21 is shown in discharge position over a dump truck 10. The dipper is discharged by the opening of dipper door 27. When the forward dipper wall 28 is inclined in a forwardly direction there is a possibility of retention of some of the material in the dipper. In dotted lines, a position of the dipper 21 is shown wherein wall 28 is substantially vertical, which allows an efficient discharge of material from the dipper 21 when the door 27 is opened.

A fluid pressure means'30 is shown between the handle 23 and dipper 21 for controlling the pivoting of the dipper about pivot 40. The tilting means 30 consists primarily of a fluid pressure cylinder 31 (FIGURE 2) having a retractible piston 32 wherein fluid pressure in the cylinder acts on the piston to maintain the piston in'retracted position and the dipper 21 in digging position as disclosed by the solid line dipper 21 of FIGURE 1. The dipper is positionable about pivot 40 to the discharge position shown, for example, in broken lines of FIG- URE l.

After the dipper discharges into the truck 10, the dipper handle 23jis retracted by winch 18 and rope 26 and the dipper 21 is then lowered toward digging position by'exten'sion of the handle. When the dipper teeth 42 are thrust into the ground, the force on the dipper pivots dipper 21 about pivot 40 to return the dipper to digging position wherein the dipper is maintained at the desired tiltfor' digging by means -During digging .when the teeth 42 of the dipper 21 emerge from the ground, the fluid pressure tilting means 30 may 'be actuated to allow partial tilt of the dipper toward its discharge position. In this'way, the dipper 'wall 28 approaches a vertical position'and the new tilted position of the dipper aids in retaining a greater quantity ,of material in the dipper than would have been carried by the dipper if no tilting had occurred. As the dipper in FIGURE 4.

driving conditions and the spilled rock or debris is likely to cause excessive truck tire wear.

In FIGURE 2 fluid pressure means 30 is pivotally attached to dipper handle 23 as at pivot block 35 and to dipper 21 at pivotal hinge means 29. The dipper is mounted for pivotal movement at hinge or pivot 40 on handle 23. Fluid pressure in cylinder 31 acts on retracted piston 32 to maintain the dipper 21 in digging position shown in solid lines, which is the position of the dipper in relation to the handle when the dipper is thrust or crowded into engagement with the ground.

The position of the dipper 21 indicated by broken lines in FIGURE 2 is the tilted position of the dipper for discharging material therefrom. The dipper discharge tilt position is obtained by the relieving or reducing the fluid pressure acting on piston 32 to'allow the piston to move outwardly of the cylinder 31 as viewed in the drawings. The tilted position of the dipper 21 delineated by the broken lines results from the action of hoist rope .20 acting at moment M from pivot 40 and the tendency of the loaded dipper to move in a counterclockwise position about pivot 32 when the pressure on piston 32' is relieved. During tilting the'forward wall 28 of the dipper reaches a nearly vertical position. The door 27 is opened by disengaging latch means 41 by a rope means (not shown). -Material in the dipper is thereby allowed to drop freely from the dipper walls.

To return the dipper 21 to the digging position of FIG- URE 2 after discharge of material, the dipper teeth 42 engage the ground as the dipper handle 23 is extended downwardly. The force on the teeth causes the dipper to pivot clockwise about pivot 40 to force piston 32 inwardly of the cylinder 31. The action of the fluid in fluid pressure means 30 during repositioning of the dipper is described in detail hereinbelow.

Reference is now made to FIGURES 3 and 4 wherein the fluid pressure circuit of fluid pressure means 30 is described. The-cylinder 31 is provided with a retractible piston-32 acted upon by a fluid pressure to maintain the piston and connected dipper 21 ina clockwise direction about pivot 40. A piston pivot 33 on piston 32 is pivotally attached to hinge29 of dipper door 27. 'A cylinder pivot 34 carried by cylinder 31 is pivotally attached to pivot lug 35 on the dipper handle 23.

To tilt the dipper in a counterclockwise direction about pivot 40 to a dipper discharge position, it is necessary to release the fluid pressure acting on piston 32. When the fluid pressure on piston 32 is released a'hoisting force applied by the hoist ropes 20 and the loaded dipper causes the dipper to discharge or dump position.

Further detail of the fluid pressure circuit 50 is shown Initially circuit 50 is charged with fluid at filler valve 53. In the disclosed embodiment hydraulic fluid is pumped into fluid pressure conduits 39. At accumulators 37, suflicient air is supplied through valves 54 to provide a cushion of air in the accumulators. The pistons 32 are in their inward or retracted position as "shown in FIGURE 4 during the charging of the circuit.

With the fluid pressure maintaining the pistons 32 in their retracted position, and with the remainder of the conduits filled with fluid, thecircuit is considered charged to maintain the pistons in the positions shown in FIGURE 4. With cylinder 31 connected to the dipper handle (FIG- URE 3) and piston 32 connected to the dipper 21 (FIG- URE 3), the fluid pressure means 30 maintainsjthe dipperin digging tilt position (FIGURE 3).

1 To tilt the dipper towarddischarge or dump position,

ropes 20 (FIGURE 2) pulling on dipper 21 at'a moment ,arm M to pivot the dipper counterclockwise about pivot 40, the piston 32 is moved outwardly of the cylinder 31 until the dipper 21 reaches discharge tilt position. A load in the dipper also tends to pivot the dipper counterclockwise about pivot 40.

To return the dipper to digging tilt position, the dipper is moved by the dipper handle 23 to engage the ground. The force occasioned by the extension of handle 23 pivots dipper 21 clockwise about pivot 40 and the fluid is forced from cylinder port 3112 by piston 32 through check valve 52 to port 31a to restore fluid pressure against piston 32 to maintain dipper 21 in digging tilt position.

If during digging an excessive force on the dipper causes an increase in fluid pressure in cylinder 31 beyond a predetermined amount, relief valve 56 opens to relieve the build-up of fluid pressure within cylinder 31 and conduits 39. When the pressure is reduced, valve 56 closes.

Thus the first embodiment of the invention has been described wherein a fluid pressure means 30 is provided to maintain the dipper in a predetermined tilted position relative to said dipper handle 23. In the embodiment disclosed, the fluid pressure maintains the dipper in digging tilt position, and release of the fluid pressure allows the dipper to be tilted to dipper discharge tilt position relative to said handle. As the fluid pressure circuit is initially charged with fluid pressure to maintain the dipper in the digging tilt position, no further fluid pressure producing means is required to maintain suflicient pressure, but rather the fluid pressure circuit as described provides for release and restoration of fluid pressure in fluid pressure means 30.

Referring now to FIGURE 5 wherein a second embodiment of the invention is shown with a dipper 21 pivotally mounted on dipper handle 23. Again fluid pressure acting on the piston means 32 maintains the dipper in digging tilt position, and the release of fluid pressure in cylinder 31 allows the dipper to pivot counterclockwise about pivot 40 to dumping or discharge tilt position. In the embodiment shown in FIGURE 5, a fluid pressure ram means 60 is mounted on the dipper handle 23, adjacent saddle block 24. A ram piston 61 extends from ram means 60 wherein one end of the piston 61 is adapted to strike the saddle block when the dipper handle is retracted, as for example, after discharge of material from the dipper. As retract rope 26 (FIGURE 1) retracts handle 23, ram piston 61 is brought into contact with saddle block 24 and the handle retraction forces the piston 61 to retract position to force fluid from the cylinder 62 into fluid pressure conduit 65. The fluid in conduit 65 is communicated with port 31a of cylinder 31 to supply a fluid pressure to force pistons 32 to retract position thereby pivoting dipper 21 to digging tilt position. In this embodiment, it is not necessary for the dipper to strike the ground during the initiation of the digging cycle, as the dipper is repositioned to digging tilt position by the fluid pressure action of the ram piston 61 striking the saddle block during retraction of the dipper handle as described hereinabove.

In FIGURE 6, a schematic diagram of the fluid pressure circuit for the ram means 60 and cylinders 31 is shown. The cylinders 31 with fluid pressure acting on pistons 32 maintain the dipper in digging tilt position. When solenoid 36 is energized by an operator to open valve 51, fluid flows from cylinder port 31a to release the pressure acting on pistons 32. The dipper is then free to be tilted about the pivot 40 by hoisting action of hoist ropes 20 until the dipper wall 28 (FIGURE 2) is substantially vertical.

The load in the dipper also acts to assist the tilting of the dipper counterclockwise about pivot 40 when pressure is relieved from cylinder 31. The fluid is allowed to flow to ports 31b and to accumulators 37. When the dipper is in discharge tilt position, the dipper door 27 is opened by unlatching latch 41 (FIGURE 2) by a means not shown but Well known in the power shovel art.

For returning the dipper to the digging tilt position,'the dipper handle 23 is retracted to cause the ram piston 61 to strike the saddle block 24 to force fluid into conduit 65 to apply a fluid pressure to the pistons 32 to position the dipper 21 into digging tilt position as hereinabove described.

Thus a fluid pressure means 30 is provided wherein the dipper is maintained in a digging tilt position. When solenoid 36 is energized the dipper is positionable to discharge tilt position by hoist ropes 20. The ram piston 61 in striking the saddle block 24 upon retraction of the handle 23 produces sufiicient fluid pressure to return the dipper 21 to digging tilt position.

In FIGURES 7 and 8 a third embodiment of the invention is shown for tilting the dipper for effieient discharge of material therefrom. The dipper 21 is pivotally attached to handle 23 as at pivot 40. A pivot lug 71 is carried by the dipper handle 23 for pivotal attachment of a link 70. The dipper door 27 is hingeably attached to dipper 21 at hinge or pivot 29, and is latched for closure by a door latch 41, which may be opened and closed by suitable means not shown. Adjacent hinge 29, link is pivotally attached at pivot 72. With the dipper 21 in the position shown in FIGURE 7, the dipper is in the digging tilt position. The digging position of the dipper is maintained as long as the door 27 remains closed.

When the dipper 21 has completed the digging portion of the cycle and the dipper is moved to a location for dumping or discharge, the embodiment of the invention of FIGURES 7 and 8 provides for the tilting of the dipper relative to the handle so that the dipper wall 28 is in a substantially vertical position. The vertical position of the dipper wall 28 allows material in the dipper to fall freely without clinging to the walls.

Referring specifically to FIGURE 8, the dipper door 27 is shown in open position. As the door swings open upon unlatching of latch means 41, the weight of the door and a material acting thereon causes the door to swing clockwise about pivot 29. Simultaneously, as the dipper door opens, the door moves pivot 72 upwardly as viewed in the drawings and thus the entire dipper is pivoted counterclockwise about pivot 40 to a position wherein the forward dipper wall 28 becomes substantially vertical.

In the embodiment disclosed in FIGURES 7 and 8, the tilting of the dipper occurs only when the dipper door is opened or closed. When the door is opened, the dipper, through linkage 70 and pivots 29 and 72, is moved to discharge tilt position as shown in FIGURE 8. To return the dipper to digging tilt position shown in FIGURE 7, the door of the dipper is closed by the weight of the door as the dipper handle swings toward digging position. As the door is closed, link 70 coacting with

pivots

29 and 72 causes the dipper to pivot clockwise about pivot 40 until the digging tilt position is reached. Latch 41 and link 70 maintain the door closed and also maintain the dipper in digging tilt position.

Thus three embodiments of the invention have been described wherein a pivotally mounted dipper is provided with a tilting means. Two of the embodiments not only provide for tilting the dipper to the discharge or dumping position but also provide a means to permit tilting of the dipper as the dipper teeth emerge from the ground in the digging portion of the cycle to allow the dipper to fill more completely and to reduce the amount of spillage from the dipper when the dipper is carried to the dump location.

Also one of the embodiments rely on dipper impact against the ground to reposition the dipper for digging, while another embodiment is provided with an additional means for repositioning the dipper to dig position prior to the engagement of the dipper teeth with the ground, and the third embodiment repositions the dipper upon closure of the door.

'Having now described and illustrated three forms of the present invention, it is to be understood that the invention is not to be limited .to the specific form or arrangement of parts herein described and shown or specifically covered by the claims.

What is claimed is:

1. Inan excavator having a boom, a saddle block .pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, means for retracting and thrusting said dipper handle, and a dipper pivotally mounted on said dipper handle, the combination of: hoist means connected to the dipper at a point forwardly spaced from the dipper pivot for raising and lowering the dipper and dipper handle and for tilting the dipper in an upward direction about the dipper pivot when said dipper is free to tilt about its pivot; and fluid pressure means, including a cylinder and a retractible piston, connected to said dipper handle and said dipper, a fluid pressure circuit for maintaining fluid pressure in said cylinder to maintain said piston in a retracted position, and fluid pressure release means in said fluid pressure circuit for releasing fluid pressure in said cylinder to allow said piston to move from retract position, said dipper being tiltable to a dipper discharge position upon release of fluid pressure and upon application of a hoisting force'on said dipper by said hoist means, and said dipper being tiltable in a downward direction about said dipper pivot to a dipper digging position by thrusting said handle and dipper into ground engagement to force said piston to retract position.

' 2.'The combination of claim 1 wherein fluid pressure is restored to said fluid pressure means as said piston is moved to retract position by ground engagement of said dipper tilting said dipper in clockwise direction about said dipper pivot.

3. In an excavator having a boom, a saddle block pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, means for retracting and thrusting said dipper handle, and a dipper pivotally mounted on said dipper handle, the combination of:

locking means connected between said dipper handle and said dipper for maintaining said dipper in a first tilt position; release means for unlocking said locking means to free said dipper to move to a second tilt position; and means connected to said dipper at a point forwardly spaced from the dipper pivot for raising and lowering said dipper and dipper handle when said locking means is engaged and for tilting said dipper upwardly about the dipper pivot to said second tilt position when said locking means is unlocked by said release means.

4. In an excavator having a boom, a saddle block pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, and a dipper pivotally mounted on said dipper handle, the combination of:

'hoist means connected to the dipper for raising and lowering said dipper'and dipper handle and for tilting said dipper upwardly about the dipper pivot when said dipper is free to tilt, fluid pressure means connected between said dipper and said dipper handle and having a.first fluid pressure for maintaining said dipper in a first tilted position; and a fluid pressure release means for said fluid pressure meansfor releasing said first fluid pressure to allow said dipper to tilt to a second tilted ,position, said hoist means adapted to tilt said dipper releasing .said first fluid pressure to allow said dipper to tilt to said first tilt position.

7. In an excavator having a boom, a saddle block pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, means for retracting and thrusting said dipper handle relative to said saddle block, and a dipper pivotally mounted on said dipper handle, the combination of: hoist means connected to the dipper at a point forwardly spaced from the dipper pivot for raising and lowering the dipper and dipper handle and for tilting the dipper in an upwardly direction about the dipper pivot when said dipper is free to tilt about its pivot; first fluid pressure means, including a cylinder and a retractible piston, connected between said dipper handle and said dipper, a fluid pressure circuit for maintaining fluid pressure in said cylinder to maintain said piston in a retracted position, and fluid pressure release means in said fluid pressure circuit for releasing fluid pressure in said cylinder to allow said piston to move from retract position to allow said dipper to tilt about its pivot; fluid pressure ram means carried by said dipper handle and moveable therewith, said ram means adapted to be actuated during retraction of said dipper handle, said dipper being tiltable to a discharge position upon release of fluid pressure by said fluid pressure release means and upon application of a hoisting force on said dipper by said hoist means; and second fluid pressure means responsive to the actuation of said ram means for producing a fluid pressure for retracting said piston to tilt said dipper from discharge position to digging position.

8. In an excavator having a boom, a saddle block pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, means for retracting and thrusting said dipper handle relative to said saddle block, and a dipper pivotally mounted on said dipper handle, the combination of: hoist means connected to the dipper at a point forwardly spaced from the dipper pivot for raising and lowering the dipper and dipper handle and for tilting the dipper in an upward direction about the dipper pivot when said dipper is free to tilt about its pivot; fluid pressure means, including a cylinder and a retractible piston, connected between said dipper handle and said dipper, a fluid pressure circuit for maintaining fluid pressure in said cylinder to maintain said piston in a retracted position, and fluid pressure release means in said fluid pressure circuit for releasing fluid pressure in said cylinder to allow said piston to move from retract position to allow said dipper to tilt about its pivot; and fluid pressure ram means carried by said dipper handle and moveable therewith, said fluid pressure ram means including a ram piston engaging said saddle block when said dipper handle is retracted by dipper handle retract. means, a fluid pressure produced by said ram means upon predetermined displacement of said ram piston by said saddle block, said fluid pressure means being responsive to said fluid pressure produced by said ram means to retract said piston of'said fluid pressure means, said dipper being tiltable to a discharge position upon release of fluid pressure by said fluid pressure release means and'upon application of a hoisting force on said dipper by said hoist means, and said dipper being tilted to digging. position in response to said fluid pressure produced by said displacement of said ramvpist-on.

9.. Man excavator having a boom, a saddle block pivotally mounted on said boom, a dipper handle slideably carried by said saddle block, means for retracting and thrusting said dipper handle relative to said saddle block, and a dipper pivotally mounted on said dipper handle, the combination of: means connected to the dipper at a point forwardly spacedfrom the dipper pivot for raising and lowering the dipper and dipper handle and for tilting thedipper in an upward direction about 9 10 the dipper pivot when said dipper is free to tilt about References Cited by the Examiner its pivot; locking means connecting said dipper and said UNITED STATES PATENTS dipper handle to maintain said dipper in a first tilted 1 603 573 10 /1926 Baker position; release means for unlocking said locking means 1710564 4/1929 Archil'jold 214 146 to allow said dipper to move to a second position when 5 2303852 12/1942 Linn X said locking means is unlocked by said releaes means; and ram means on said dipper handle actuated by re- FOREIGN PATENTS traction of said dipper handle to lock said locking means 444,728 5/1927 G in response to ram means actuation and to return said dipper to said first position. 10 HUGO O. SCHULZ, Primary Examiner.

Claims

1. IN AN EXCAVATOR HAVING A BOOM, A SADDLE BLOCK PIVOTALLY MOUNTED ON SAID BOOM, A DIPPER HANDLE SLIDEABLY CARRIED BY SAID SADDLE BLOCK, MEANS FOR RETRACTING AND THRUSTING SAID DIPPER HANDLE, AND A DIPPER PIVOTALLY MOUNTED ON SAID DIPPER HANDLE, THE COMBINATION OF: HOIST MEANS CONNECTED TO THE DIPPER AT A POINT FORWARDLY SPACED FROM THE DIPPER PIVOT FOR RAISING AND LOWERING THE DIPPER AND DIPPER HANDLE AND FOR TILTING THE DIPPER IN AN UPWARD DIRECTION ABOUT THE DIPPER PIVOT WHEN SAID DIPPER IS FREE TO TILT ABOUT ITS PIVOT; AND FLUID PRESSURE MEANS, INCLUDING A CYLINDER AND A RETRACTIBLE PISTON, CONNECTED TO SAID DIPPER HANDLE AND SAID DIPPER, A FLUID PRESSURE CIRCUIT FOR MAINTAINING FLUID PRESSURE IN