US3523614A

US3523614A - Hydraulic crane and bucket control

Info

Publication number: US3523614A
Application number: US670345A
Authority: US
Inventors: Luther Walker
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-09-25
Filing date: 1967-09-25
Publication date: 1970-08-11
Anticipated expiration: 1987-08-11

Description

1970 .L. WALKER 3,523,614

' I HYDRAULIC CRANEAND BUCKET CONTROL Filed Sept. 25, 1967 4 Sheets-Sheet l EJL l I i E- 40 I o o lulu. M I I 47 H I V 30 I \6 H 2 L 36: 50 \5 I l 40% HI WHI'UHII'W .!I|" In I I" I O O o INVENTOR LUTHER WALKER.

ATTORNEY Aug. 11, 1970 WALKER 3,523,614

HYDRAULIC CRANE AND BUCKET CONTROL Filed Se t. 25, 1967 4 Sheets-Sheet 2 5EI i -ao LUTHER WALKER ATTORNEY L. WALKER HYDRAULIC CRANE AND BUCKET CONTROL Aug. 11, 1970 4 Sheets-Sheet 25 Filed Sept. 25, 1967 INVENTOR LUTHER YVALKEQ ATTORNEY 1-970 L. WALKER 3,523,614

HYDRAULIC'CRANE AND BUCKET CONTROL' Filed Sept. 25, 1967 4 Sheets-Sheet 4 E: g lEL PRES5URE 35 CONTROLVALVE- A GENERATOK 6 fioLENOlD VALVES AuxlLxARY I151 \36 use r as POWER PLANT z \6 m n4- HYDRAUUC. PUMP M H 15 36 33 7o RESEEVOIF? Foal/f; R 47 \44 SOURCE \43 I M17746 6 T0 PRESSURE sagas 80 INVENTOR LurHE/e WA L KE 2 BY W ATTORNEY United States Patent Office 3,523,614 Patented Aug. 11, 1970 US. Cl. 212-42 Claims ABSTRACT OF THE DISCLOSURE A unitary drum has two cables wound thereon, one connected by means of a crane to a dredging bucket to raise or lower it and the other being connected to means for opening and closing the bucket, a hydraulically operated device having engagement with the last named cable to lengthen it or shorten it to open and close the bucket. A single control lever is universally mounted and movable back and forth to control the operation of the drum and the main power source, the lever being transversely movable to control the swinging of the crane between loading and unloading positions.

BACKGROUND OF THE INVENTION The present invention is particularly adapted to use in the field of underwater dredging to open channels and for other purposes. The bucket is dropped with the jaws open into the water, and moves as rapidly as gravity will carry it to engagement with the bottom of the waterway so that the edges of the bucket will dig thereinto. The cable is then pulled to close the bucket, and with the bucket maintained closed, it is raised to a point above the water and then swung over a scow, or other receiving structure, whereupon the bucket is opened to discharge its load. The crane is then swung into position above the point to be dredged with the bucket still open, whereupon the operation is repeated.

The crane and bucket control mechanisms in common use require the pushing and pulling of a number of levers, these operations being performed usually by both the hands and feet of the operator. Much difficulty is encountered in properly paying out and pulling in the cables which respectively operate the bucket jaws and raise and lower the bucket. In dredging underwater, the operator often cannot see the actual bucket, and this results many times in the paying out of excess cable for opening and closing the bucket. This often causes the latter cable to become wrapped around the bucket or other-wise entangled therewith. Other difficulties are encountered, including the confusing sequential operation of the various control members.

SUMMARY OF THE INVENTION Two drums are arranged in end-to-end relation with means normally connecting them to simultaneously rotate as a unit. A cable is wound on each drum, and both cables pass around pulleys on the end of a crane boom and thence downwardly to a dredging bucket. The lower end of one cable is connected to the bucket to raise or lower it, while the other cable is connected to a lazy tongs, movement of the upper end of which determines the opening and closing of the bucket. It is desirable to simultaneously wind both cables on the drum units and unwind them simultaneously and at the same speed. To provide for relative movement of the free end of the bucket jaw control means, it is necessary that the end of such cable move lengthwise relative to the cable which supports the bucket. To this end, the control cable passes around two spaced pulleys between the drum and the end of the crane boom, and a hydraulically bodily movable pulley is arranged between such pair of pulleys and movable relative thereto to increase or decrease the control cable length between the drum and the bucket controlling lazy tongs.

The unitary drum is driven from a power source which may be an electric motor or an internal combustion engine. The driven shaft from the motor extends entirely through the drum and carries clutch means having shoes engagea'ble with the drum to positively drive it for winding the cables and to act as a clutch to determine the speed at which the cables are reeled out when the bucket is lowered. To permit the friction shoes of the clutch to act as both a clutch and a brake, an overrunning clutch is mounted in the driven shaft to permit power rotation of the shaft in one direction and to prevent reverse rotation when the friction shoes are operating as brakes.

A control lever or stick is adapted to control the functions of the cable reeling and unreeling mechanism. The lever normally occupies a neutral position in which the power source is idling or running at low speed and the friction shoes act as brakes to prevent rotation of the drums. Movement of the stick in one direction accelerates the power source and starts the friction shoes to rotate the drum. Movement of the stick in the opposite direction permits the power source to idle and permits the unreeling of the main cables under the control of the operator.

The stick is universally mounted and rocking movement in a direction transverse to that previously described controls the swing motor to rotate the crane between loading and unloading positions.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side elevation of the crane boat showing the dredging bucket elevated above the water;

FIG. 2 is a plan view of the same;

FIG. 3 is a side elevation of the cable drum unit and associated parts, a portion of the drum being broken away;

FIG. 3A is an enlarged fragmentary sectional view showing a modified form of the invention, parts being shown in elevation;

FIG. 4 is a section on line 4--4 of FIG. 3;

FIG. 5 is a similar view on line 5-5 of FIG. 3;

FIG. 6 is a similar view on line 66 of FIG. 3;

FIG. 7 is a similar view on line 7-7 of FIG. 3;

FIG. 8 is a fragmentary slightly enlarged sectional view showing the automatic brake of FIG. 6;

FIG. 9 is a detailed sectional view on line 9-9 of FIG. 7;

FIG. 10 is a diagrammatic view of the system as a whole;

FIG. 11 is a detailed view of the lengthening and shortening means for the cable which controls the drum; and

FIG. 12 is a detailed view showing the connection between the motor control cable and the main motor or engine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing, and particularly FIG. 1, the numeral 10 designates a conventional crane boat having a rotatable platform 11 provided with conventional means, further referred to below, for swinging it about a vertical axis between loading and unloading positions. On the platform 11 is mounted a crane boom 12, pivotally supported on the platform 11 at its lower end. Two pulleys 14 are mounted on the free end of the boom 12 and two

cables

15 and 16 pass around these pulleys. A conventional dredging bucket 20 is provided having the usual clam shell jaws 21 pivotally supported as at 22 and operable by a conventional lazy tongs 23, the lower ends of the arms of which are pivotally connected in the usual manner as at 24 to the respective jaws 21. The lower end of the cable 16 is connected as at 25 to the upper ends of the lazy tongs 23. When the cable 16 is pulled up wardly, the bucket is closed, and when this cable is released, the jaws 21 open by gravity in accordance with the conventional practice.

On the platform 11 is arranged a cable reeling and unreeling mechanism indicated as a whole by the numeral 30. This mechanism is shown in detail in FIGS. 3 to 9, inclusive. A heavy power driven shaft 31 extends through and beyond a pair of

drum elements

32 and 33 connected together for simultaneous bodily rotation as a unit by means to be described. The cable is wound around a drum element 33, while the cable 16 is wound about the drum element 32. Referring to FIG. 9, the drum elements are provided at their adjacent ends with external gears 35 engageable with the teeth of an internal gear 36 spanning across both gears 35. The drum element 32 is provided with an external annular flange 37 and a screw clamp 38 is engageable against the outer face of the flange 37 and against the remote face of the internal gear 36 to fix the latter in position. Three or more of these clamps are preferably employed at circumferentially spaced points around the drum units. The gears described do not function as gears but only as positive clutch elements to fasten the

drum elements

32 and 33 together for simultaneous rotation as a unit.

Beyond the ends of the drum unit bearings 40 support the shaft 31, these bearings being suitably fixed to the platform 11. The shaft 31 is driven from a main power source having an output shaft 46 extending into a speed reduction unit 47. The shaft 31 constitutes the output shaft of the speed reducing mechanism 47 and between such mechanism and the adjacent bearing 40 is arranged an overrunning clutch 48 which permits the power driving of the shaft 31 in one direction but prevents reverse rotation of such shaft for purposes which will become apparent.

The

drum elements

32 and 33 are fixed to spiders 52 having axial bearings 53 rotatable on the shaft 31. Thus, in itself, the drum unit 30 is rotatable relative to the shaft 31, and clutch and brake means are provided for positively driving the drum unit 30 in one direction for winding the cables and for controlling the reverse rotation of the drum unit in paying out the cables.

The means-just described is shown in FIG. 5. This means comprises a unit for each

drum element

32 and 33. Each of the clutch and brake devices comprises a collar 58 fixed as at 59 to the shaft 31 and provided with diametrically opposite arms '60 and 61, the free end of the former of which is pivoted as at 62 to the adjacent ends of brake shoes 63 having brake linings 64. The free ends of the brake shoes of each unit are adapted to be expanded by a conventionally operated hydraulic cylinder device 65 to which hydraulic fluid is fed respectively through hoses 63' and 64' within an axial opening 67 through the shaft 31. These hoses are connected with an external hose 66 through a swivel 68.

The free ends of the brake shoes are urged together by a spring 69 in accordance with conventional practice, and the brake shoes are operated by admitting hydraulic pressure to the cylinder 65 of each brake unit.

To prevent uncontrolled unreeling rotation of the drum unit 30 in the event of a failure in hydraulic pressure, an automatic brake is provided for the drum unit, such brake being shown in FIGS. 6 and 8. The automatic brake comprises brake shoes 70 pivotally connected at one end as at 71 and having brake linings 72 engageable with the outer surface of the drum element 33. The free end of one brake shoe 70 is pivoted as at 73 (FIG. 8) to the rod 74 of a piston 75 operable in a cylinder 76, the latter of which is pivoted as at 77 to the other brake shoe 70. A fluid line 80 supplies hydraulic pressure to a cylinder 76 beneath the piston 75. This piston is biased to the braking position shown in FIG. 8 by a heavy spring 81. The line 80 is connected to any pipe of the system described below in which hydraulic pressure is normally present. Therefore, the brake shoes 70 will be normally released and will be automatically applied if hydraulic pressure in the source should fail.

For the purposes of fixing the

drum units

32 and 33 against rotation when work is being performed thereon, a chain may be provided at each end of the drum unit. Each chain may be connected at one end to a fixed eye 86 and may be provided at its free end with a hook 87 engageable with an eye 88 fixed to the end of each drum element.

The friction shoes 64 (FIG. 5) operating as a brake, obviously will generate heat. To assist in dissipating such heat, the drum element 33 in the end thereof remote from the power source is provided with fan blades 90 (FIG. 6) to pull air through the drum unit.

The system for controlling the apparatus is shown in FIG. 10. An operators seat is arranged on the platform 11 and adjacent such seat is arranged a lever or stick 96 extending through an opening 97 in the deck 11. A pair of spaced bearings 98 is arranged beneath and fixed to the deck 11 and rotatably and slidably supports a cylinder 99. The stick 96 extends through this cylinder and has its lower end connected to balancing springs 100 which tend to maintain the stick in the vertical neutral position, and to which position the stick returns when released. The stick 96 extends through diametrically opposite slots 101 in the cylinder 99 and is pivoted to such cylinder as at 102.

Beneath the cylinder 99, one end of a cable is secured to the stick 9'6 and passes around upper and lower pulleys 111 and 112. The lower end of the cable 110 (FIG. 12) passes through an opening 113 in the pivoted arm 114. This arm may be the rheostat control arm if the power source 45 is an electric motor, and is the throttle control lever if the power source is an internal combustion engine. Beneath the arm 114, the cable 110 is providoed with a head 115 and a compres sion spring 116 is interposed between the head 115 and the arm 114. In the position shown, the arm 114 is in idling position, and if the cable 110 is pulled, the arm 114 moves counterclockwise to accelerate the power source. If the cable 110 is slacked off, it merely moves through the opening 113 and imparts no movement to the arm 114. Obviously the arm 114 is moved in a motoraccelerating direction by moving the upper end of the stick 96 to the right in FIG. 10.

Opposite the connection of the cable 110 to the stick 96, a second cable 120 is connected at its upper end to the stick and extends around pulleys 121 and 122 to operate an arm 123 of a valve mechanism 124, which is a pressure control valve and pressure release valve. The arm 123 is biased by a spring 125 to its normal position in FIG. 10 in which position pressure is supplied from a source to be described through the line '66. The connection of the cable 120 to the arm 123 is similar to the arrangement shown in FIG. 12, the cable 120 being provided with a head 128, with a spring 129 interposed between the head 128 and arm 123. If the stick 96 is moved at its upper end to the right to accelerate the power source, the cable 120 will be pushed at its upper end and is free to slide through the arm 123. If the stick 96 is moved at its upper end to the left, the arm 114 is released to the motor-idling position and the arm 123 will be moved to decrease pressure in the line 66 through means to be described.

An auxiliary power plant drives the generator 136 to provide electric power when needed in the present mechanism and to provide lights for the boat 10. A shaft 137 from the generator drives the hydraulic pump 138 through the medium of a conventional clutch 139 which may be released when desired. The pump 138 is supplied with hydraulic fluid through a line 142 leading from a reservoir 143 having a return line 144. Maximum pressure is maintained in the line 66 when the arm 114 is in idling or accelerated position with the arm 123 in the position shown in FIG. 10. The pressure is reduced in the line 66 by clockwise movement of the arm 123, and pressure is relieved from the line 66 to the valve mechanism 124 through a line 145, and from the valve mechanism 124 through a line 146 leading to the line 144.

As previously stated the

cables

15 and 16 extend from the drum unit 30 to the bucket 20. Centrally of the platform 1.1 is arranged a rigid vertical mast or other structure 150 carrying a pulley 151 around which the cable 15 passes. The mast 150 carries spaced bracket arms 154 (FIG. 11) carrying pulleys 155 around which the cable 16 passes. Between the arms 154 is arranged another bracket arm 156 carrying a hydraulic cylinder 157 having a piston 158 therein biased to the left in FIG. 11 by a spring 159. The piston 158 carries a piston rod 164 supporting a pulley 165 between the pulleys 155. When the pulley 165 occupies the solid line position in FIG. 11, the dredging bucket is opened as jaws 21 pivot because of gravitational pull due to the fact that tongs 23 are no longer under tension from cable 16. When it is desired to close the dredging bucket, hydraulic fluid is admitted to the chamber behind the piston 158 through a fluid line 168 to move the piston 158 to move the pulley 165 to the dotted line position, thus pulling on the cable 16 and cables 25. The tension of the left cable 25 results in a rotationad force in clockwise movement about the right point 24 so as to move the right jaw upward and to the left as if point 24 were the fulcrum of a lever. The tension of the right cable 25 results in a rotational force in counterclockwise movement about the left point 24 so as to move the left jaw upward and to the right as if point 24 were the fulcrum of a lever. Point 22, which was initially at a vertical height below that of point 24 when jaws 21 were in the open position, moves upward to a vertical height above that of point 24 as left and right jaws 21 move toward each other finally mating in the closed position. Fluid is relieved from the ram cylinder 157 through a hydraulic line 169.

Referring to FIG. 10, it will be noted that the valve mechanism 124 is supplied with hydraulic pressure from the pump .138 through a main line 175 and branch line 176. The line 175 extends to a solenoid operated valve 177 to which the pipe 168 is connected. A button 178 on the stick is electrically connected as at 179 to the solenoid 177. The relief line 169 from the ram cylinder 157 is 7 connected to a solenoid valve 181 leading to a line 182 feeding into the return line .144. A second push button 183 at the upper end of the stick 96 is electrically connected as at 184 to the solenoid valve 181. Pressing the button 178 opens the valve 177 to supply hydraulic fluid to the ram cylinder 157 and pressing the button 183 and releasing the button 178, releases pressure from the ram cylinder 157 so that the spring 159 will return the piston 158 to the left hand end of the cylinder 157, thus releasing the jaws of the dredging bucket for movement to close position.

A swing motor 190 is provided with a reversing control arm 191 shown in neutral position in FIG. 10. This motor drives a swing drum 192 fromwhich a cable 193 extends to a pulley fixed to the platform 11 therebeneath. Accordingly, swinging the arm .191 in a clockwise direction will rotate the platform 11 in one direction, while rotation of the arm 191 in a counterclockwise direction will reverse swinging movement of the platform 11. The means for swinging the platform 11 is conventional and forms no part of the present invention except for the means for controlling the motor 190. The arm 191 is connected to ends 195 of a cable which is wrapped around the cylinder 99 and extends around pulleys 196 adjacent the arm 191. It will be apparent that moving the lever or stick 96 to rock the cylinder 99 on its axis will rock the arm 191 to control the swing motor 190.

There are times when it is desirable to free one of the

drum elements

32 or 33 for rotation independently of the shaft 31 while rotating the other drum element, for example, when work is to be performed on one drum element or a new cable is to be wound thereon. To this end,

the modification shown in FIG. 3A is preferably employed. Associated with each brake device a solenoid operated fluid valve 200 is connected in each of the lines 63 and 64'. For the electrical control of these solenoid valves, two slip rings 202 are carried by and insulated from the shaft 31. A wire 203 is connected to each slip ring, and each slip ring is engaged by the brush 201 carried by the associated solenoid valve 200. The wires 203 extend through the shaft 31 beyond the drum element 33 and are respectively connected to slip rings 204 engaged by brushes 205. Means (not shown) including manually operable switches, control the circuits including the brushes 205, wires 203, slip rings 202, brushes 201 and solenoid valves 200. Thus, either brake element may be closed to the source of fluid pressure to render it inoperative for clamping the associated drum element to the shaft 31.

OPERATION Assuming that the motor 45 is idling and the arm 123 is in the position shown, fluid pressure will be supplied to line 66 and thence through

lines

63 and 64, to the brake cylinders 65, thus expanding the brake shoes 63 to lock the drum unit 30 to the shaft 31. If the dredging bucket 20 is in the position shown in FIG. 1, the operator will move the upper end of the stick 96 toward himself, thus slacking oif on the cable and pulling on the cable to swing the arm 123 to reduce pressure in the line 66. At the same time he will press the button 178 to operate the solenoid valve 177 and relieve pressure from the ram cylinder 157 to move the pulley to the solid line position in FIG. 11. The latter action will open the jaws of the bucket, and reducing pressure in the line 66 will reduce pressure in the brake cylinders 65. The overrunning clutch 48 will prevent reverse rotation of the shaft 31, and releasing the pressure of the brake shoes 63 against the drum unit will allow the latter to turn to pay out the

cables

15 and 16. The brake shoes are preferably released from the drum unit so that the bucket may fall at a relatively high speed and cause the edges of the bucket to dig into the mud or sand at the bottom of the waterway.

When this operation has been completed, the operator will first press the button 183 and release the button 178, both operations being performed without removing the hand from the stick 96. The valve 177 will be deenergized and will close, while the valve 181 will be energized to admit pressure to the ram cylinder 157. Thus the bucket will tend to close.

The operator will now move the stick 96 to turn it in a clockwise direction about its pivotal connection with the cylinder 99. The lower end of the stick moves to the left to release the arm 123 for movement to its normal position shown in FIG. 10, thus admitting full hydraulic source pressure to the line 66 and thus to the brake cylinders 65 to set the brake shoes 63 (FIG. 5). The movement of the stick 96 described will pull on the cable 110 to accelerate the motor 45, thus pulling on both

cables

15 and 16. Accordingly, the bucket will be lifted and will close to bring up with it the dredged material.

When the bucket has been elevated to the proper height, the operator will return the stick 96 to the normal position and the motor 45 will idle. The arm 123 will remain in the same position, thus maintaining braking pressure in the cylinders 65. The operator will then swing the stick 96 transversely to swing the arm 191 and thus operate the swing motor until the bucket is over the barge or other receiving receptacle. The swing motor arm 91 will then be returned to neutral position and the operator will press the button 178, resulting in energization of the ram cylinder 157 to move the pulley 165 to the solid line bucket-dumping position in FIG. 11. The bucket having been dumped, the operator will reverse the swing motor to rotate the platform 11, thus moving the bucket back to the position shown in FIG. 1 ready for the next dredging operation.

When it is desired to service one of the brake drum elements, for example, to wind a cable thereon, while leaving the other drum element free, the switches connected to the brushes 205 may be selectively operated. For example, if the drum element 32 is to have a cable wound thereon, the brake mechanism associated with the drum element 33 will be rendered inoperative by closing the associated solenoid valve 200. The chain 85 associated with the drum element 33 may be hooked to the eye 88, whereupon the drum element 33 will be fixed against rotation. This operation, of course, will be performed with the drums disconnected from each other by releasing the clamps 38 and sliding the member 36 to the right as viewed in FIG. 9.

From the foregoing, it will be apparent that the

cables

15 and 16 are always wound and unwound with respect to the drum unit 20 at the same speed, thus preventing any tangling of the lines. It also will be apparent that all operations of the mechanism are controlled by the single stick 96. Movement of this stick controls the winding and unwinding operations, the opening and closing of the bucket through operation of the

buttons

178 and 183, and the controlling of the swing motor 190 to control rotation of the platform 11. It is never necessary for the operator to remove his hand from the stick 96. All operations are controlled by a single hand of the operator, there being no levers to be moved by the other hand of the operator or by his feet. It requires much less experience on the part of the operator to control the present system, and an operator without experience can quickly learn to master the various single-stick controls described.

From the foregoing it will now be seen that there is herein provided an improved control mechanism which accomplishes all of the objects of this invention and others, including many advantages of great practical utility and commercial importance.

What is claimed is:

1. Operating means for a dredging bucket having pivoted jaws and operating means for opening and closing said jaws, comprising a pair of cables connected respectively at one end to said bucket and to said operating means, a unitary drum around which the other ends of said cables are wound, a power source for driving said drum, a bucket jaw control means enterable into and movable through the plane of a portion of one of said cables to operate said operating means to close said bucket, retraction of said bucket jaw control means allowing said jaws to open by gravity, a shaft driven by said power source and extending through said drum, a combined clutch and brake device carried by said shaft and having a pair of friction shoes expandable into engagement with said drum, means for controlling the expansion of said shoes, a common control lever for said power source and said last-named means, said bucket jaw control means comprising a support, a pair of spaced pulleys around which said one of said cables passes between said drum and said bucket, a single pulley intermediate said pair of pulleys movable through the plane of said lastmentioned cable to pull it and relatively shorten the end connected to said operating means to close said jaws and retractable to release said jaws for movement to the open position, and a hydraulic ram for moving said single pulley relative to said pair of pulleys, said means for controlling the expansion of said shoes comprising hydraulic cylinders, said lever controlling the supply of hydraulic fluid under pressure from said source to said hydraulic cylinders and said hydraulic ram, and means including devices carried by said lever for supplying hydraulic fluid from said source to said ram and for relieving pressure therefrom.

2. Apparatus according to claim 1 wherein said means for controlling said ram comprises a pair of solenoid operated valves one of Which is connected between said hydraulic pump and said ram, a hydraulic reservoir, the

other of said solenoid controlled valves being connected between said ram and said reservoir.

3. Apparatus according to claim 2 wherein said devices carried by said lever comprise a pair of manually operable switches connected respectively to said solenoid controlled valve.

4. Operating means for a dredging bucket having pivoted jaws and operating means for opening and closing said jaws, comprising a pair of cables connected respectively at one end to said bucket and to said operating means, a unitary drum around which the other ends of said cables are wound, a power source for driving said drum, a bucket jaw control means enterable into and movable through the plane of a portion of one of said cables to operate said operating means to close said bucket, retraction of said bucket jaw control means allowing said jaws to open by gravity, a shaft driven by said power source and extending through said drum, a combined clutch and brake device carried by said shaft and having a pair of friction shoes expandable into engagement with said drum, means for controlling the expansion of said shoes, a common control lever for said power source and said last-named means, said bucket jaw control means comprising a support, a pair of spaced pulleys around which said one of said cables passes between said drum and said bucket, a single pulley intermediate said pair of pulleys movable through the plane of said lastmentioned cable to pull it and relatively shorten the end connected to said operating means to close said jaw and retractable to release said jaws for movement to the open position, and a hydraulic ram for moving said single pulley relative to said pair of pulleys, a rotatable platform, a boom carried by said platform and having pulley means around which said cables extend for connection with said bucket and said operating means, a rigid mast to which said ram is connected, a motor for rotating said platform, and means connected to said lever and operable in a different movement thereof for operating said motor to turn said platform in either direction.

5. Apparatus according to claim 4 provided with a cylinder arranged beneath said platform, means carried by said platform therebeneath for supporting said cylinder for sliding and rotational movement, said means for operating said motor comprising cables wound on said last-named cylinder, and a control arm connected to said motor and to which said last-named cables are connected, whereby movement of said lever in a plane transverse to the axis of said last-named cylinder will swing said motor control arm.

References Cited UNITED STATES PATENTS 983,772 2/1911 Sain 37-71 X 1,000,677 8/1911 Hayward 214-656 1,047,233 12/1912 Jackson 37-71 X 1,791,743 2/1931 Osgood 254- 1,971,126 8/1934 Allard 254-185 X 2,781,134 2/1957 Weir et a1 212-38 2,808,166 10/1957 Stine 214-656 2,852,316 9/1958 Staley 188-170 X 2,907,415 10/1959 Norman 188-170 X 2,947,397 8/1960 Pietsch 254-185 X 3,043,445 7/1962 Holmes 212-38 X 3,286,852 11/1966 Haulotte 212-38 3,291,450 12/1966 Schlechter 254185 3,291,451 12/1966 Trollope 254-185 ROBERT E. PULFREY, Primary Examiner C. D. CROWDER, Assistant Examiner US. Cl. X.R.