US3152706A

US3152706A - Grapple device

Info

Publication number: US3152706A
Application number: US161587A
Authority: US
Inventors: Marcus L Conrad
Original assignee: Clark Equipment Co
Current assignee: Doosan Bobcat North America Inc
Priority date: 1961-12-22
Filing date: 1961-12-22
Publication date: 1964-10-13
Anticipated expiration: 1981-10-13

Description

Oct. 13, 1964 M. L. CONRAD GRAPPLE DEVICE Filed Dec. 22, 1961 2 Sheets-Sheet 1 @ccumulutor) FIG. 4

iNvENToR Marcus L. Conrad BY W M ATTORN EY M. L- CONRAD GRAPPLE DEVICE Oct. 13, 1964 2 Sheets-Sheet 2 Filed Dec. 22, 1961 INVENTOR Marcus L. Conrad fikmwe am ATTORNEY United States Patent 3,152,706 GRAPPLE DEVICE Marcus L. Conrad, Stevensville, Mich, assignor to Clark Equipment Company, a corporation of Michigan Filed Dec. 22, 1961, Ser. No. 161,587 4 Claims. (Cl. 214-147) This invention relates to material handling devices, and more specifically to tractor mounted grapples for handling heavy objects of irregular shape and size, such as large pieces of quarried stone and the like.

It is known to use very large pieces of stone as riprap for dams, dikes and causeways, and such stones may weigh as much as 30,000 lbs. each and in a typical case may have dimensions which are roughly 6 ft. x 6 ft. x 8 ft. The handling of such rocks presents a diflicult problem, especially so when the rocks are irregular in shape and must be picked up, transported, and then deposited in or on a conveyance such as a heavy truck or railroad car. When such rocks are to be moved considerable distances they are commonly carried in gondola-type rail road cars which typically may have sides 8 ft. or more in height above the ground. Moreover, it will be appreciated that a rock of the size and weight mentioned must be deposited gently in the railroad car or other conveyance, since dropping such a rock even a few inches could badly damage the conveyance into which it is being loaded. It is also necessary, of course, to unload such rocks from the conveyance again near the site where the riprap is to be placed, after which they must again be transported and then put into final position.

Prior to the present invention, to the best of my knowl edge, there was no single device available which was capable of handling expeditiously such heavy objects of irregular shape and size as described hereinbefore, although it was known prior to the present invention to use other types of grapples in conjunction with cranes, tractors and other machines. With my device, as many as forty rocks weighing an average of 9.1 tons apiece have been moved 110 feet in one hour. In another situation a piece of granite weighing 31,200 lbs. was transported from a quarry floor to a rail heading 2,700 ft. away in less than 6 minutes.

The object of the present invention is to provide a vehicle mounted grapple device which is capable of picking up, transporting, loading and unloading very large rocks of irregular size.

In carrying out my invention in a preferred embodiment, I provide a generally downwardly disposed grapple pivotally connected to the forwardly extending boom arms of a wheeled tractor. The grapple includes a laterally elongated grapple arm and a pair of laterally spaced grapple arms disposed in diverging relation relative to the elongated grapple arm and pivotally connected thereto in confronting relation therewith to form an inverted generally U-shaped opening therebetween.

The above object and other objects, features and advantages of my invention will become more readily apparent to persons skilled in the art from the following detailed description when taken in conjunction with the accompanying drawing wherein:

FIGURE 1 is a perspective view of a tractor embodying the invention,

FIGURE 2 is a side elevational view of my invention on a larger scale showing the grapple device and a portion of the tractor boom arms,

FIGURE 3 is a top plan view of the same portion of the invention as FIG. 2.

FIGURE 4 is a schematic drawing showing the fluid circuit for actuating the pair of diverging grapple arms, and

3,152,705 Patented Oct. 13, 1964 ice FIGURE 5 is a fragmentary view of an enlarged scale showing to advantage one of the C-shaped retaining rings.

Referring to FIG. 1, the numeral 10 denotes generally a tractor having a pair of front drive wheels 12 and a pair of rear drive-steer wheels 14 (only one of which is shown). The tractor 10 includes a body 16, a steering control wheel 18 located at an operators station and a pair of forwardly extending parallel boom arms 20 pivotally connected to body 16 at 22 and rigidly connected adjacent their forward ends by a transverse brace member 26. The boom arms 20 are arranged to be pivoted about pivotal connections 22 by means of upwardly and forwardly inclined piston and cylinder type fluid actuators 24 (only one of which is shown) pivotally connected at one end to the respective boom arms 20 intermediate the ends thereof and pivotally connected at their other ends to body 16.

Referring also now to FIGS. 2 and 3, a generally downwardly opening grapple 28 is pivotally connected to the forward ends of boom arms 20. The grapple 28 includes a rear laterally elongated arcuate grapple arm 30 pivotally connected to boom arms 20 and a pair of front arcuate laterally spaced apart grapple arms 32 pivotally connected to grapple arm 30 in confronting relation therewith to form an inverted generally U-shaped opening between the grapple arms in the positions illustrated in FIGS. 1 and 2.

The elongated grapple arm 30 includes a pair of laterally spaced part end plates 34 each having a forwardly curved upper portion 36 and a toothed or serrated lower portion 38 on the forward edge thereof. The end plates 34 are rigidly secured together to form elongated grapple arm 30 by means of three vertically spaced apart transversely extending and horizontally disposed brace members 40 of rectangular cross-section. Brace members 40 are inclined rearwardly, as shown, to present upwardly facing inclined surfaces 41 to the load to aid in cradling the load between rear grapple arm 30 and the forward grapple arms 32. The corners 40a of brace members 40 which thus engage the load likewise are useful in holding the load since these corners form sharp edges which tend to bite into the load and aid in gripping a load between grapple arm 30 and the serrations 114 on forward grapple arms 32. The upper portions 36 of end plates 34 are rigidly secured together by means of a pair of longitudinally spaced apart rectangular brace members 42 that extend transversely therebetween. Also extending between upper portion 36 is a generally horizontally disposed support plate 44 which abuts the upper edges of brace plates 42. In addition to serving as a brace member between end plates 34, support plate 44 also serves to support grapple arms 32 as will be explained in greater detail hereinafter.

Members

40, 42 and 44 preferably are secured to end plates 34 by welding, although other suitable means of connection may be used.

At this point it will be appreciated that grapple arm 30 is an elongated unitary structure and provides a large area that is well adapted to engage and grip an object of irregular shape since the brace members 40 provide central engagement between end plates 34 which serve to prevent the object engaged from slipping sideways out of contact with grapple arm 30. Further, end plates 34 provide through the serrated portions 38 means for gripping an irregular surface, as do inclined brace members 40. Grapple arm 30 is pivotally connected to boom arms 20 by means of a pair of generally vertically disposed double ended bracket connectors 52. Each bracket connector 52 includes an outboard support plate 46 disposed outwardly of the adjacent end plate 34 in spaced relation thereto and secured thereto by means of a rectangular spacer member 48 and an upwardly extending triangular member 50 as best shown in FIGS. 2 and 3. The lower ends of bracket connectors 52 are adapted to receive respectively the forward ends of boom arms 20 between outboard support 46 and end plate 34 whereby grapple arm 31 is pivotally connected to boom arms 20 by means of the pair of pins 58 passing respectively through

plates

34 and 46 and boom arms 20. Referring to FIG. 5, each pin 58 is held from both axial and rotational movement by means of a O-shaped retainer ring 611 which engages a pair of diametrically disposed parallel slots 62 adjacent the end of pin 58 and is secured to the adjacent outboard support plate 46 by means of a plurality of machine screws 64. Due to the pin and

bracket connections

58, 52 the grapple arm 30 is pivotal on boom arms 26 about a horizontally disposed axis through pins 58 transverse to tractor 10.

The grapple arm 39 is actuatable about connections 52, 53 by means of a pair of double acting fluid actuators 66 including, respectively, a cylinder 68 within which is slidably disposed a piston (not shown) and a piston rod 70 attached to the piston and extending outwardly through one end of cylinder 68. The cylinders 63 are pivotally connected, respectively, to boom arms 2% by pin and bracket connections 74 and piston rods 70 are pivotally connected, respectively, to the upper ends of bracket connectors 52 by means of the pins 76 passing respectively through plates 46 and t and rods 70. Each pin 76 is held from axial and rotational movement by means of a C-shaped retaining ring 78 engaging a pair of diametrically disposed parallel slots 80 adjacent one end thereof, the same as ring 60 which is shown to advantage in FIG. 5. The C-shaped retaining ring 78 is secured to the adjacent outboard support plate 46 by means of a plurality of machine screws 82.

Secured to support plate 44 is a pair of forwardly extending actuator and grapple arm supports 84 which are disposed to angle outwardly about degrees with respect to the horizontal longitudinal axis of body 16, as shown in FIG. 3. Each actuator and grapple arm support 84 includes a pair of spaced apart parallel plates 86 of generally L-shape having an elongated base leg 58 and an upwardly extending vertical leg 93. Plates 86 are secured to support plate 44 by any suitable means, such as welding, and reinforced by a spacer plate 92 (only one of which is shown) disposed between plates 86 and secured thereto, preferably by welding. The grapple arms 32 are disposed between respective pairs of parallel plates 86 adjacent the end of base legs $8 and pivotally connected thereto by means of a pin 94.

A pair of double acting piston and cylinder type fiuid actuators 1G0 serve respectively to pivot grapple arms 32 about pins 94. Each fluid actuator 1% includes a cylinder 102, a piston 103 (FIG. 4) slidably disposed in the cylinder and a piston rod 164 connected to the piston and extending outwardly through one end of cylinder 192. The end of cylinder M12 is disposed between the vertical legs 90 of parallel plates 86 and pivotally connected there- 'to by means of a pin 1656. The piston rods 1114 are pivotally connected respectively to grapple arms 32 by means of a pin and bracket connection 112.

Each grapple arm 32 is generally arcuate in shape and has the serrated or toothed portion 114 adjacent the lower ends thereof and in facing relation with toothed portion 38 of end plates 34. Because of the angle at which actuator and grapple arm supports 34 are disposed, the ends of grapple arms 32 tend to move closer together as grapple arms 32 are actuated toward grapple arm 30, and to move further apart as grapple arms 32 are actuated away from grapple arm 31). In other words, the lateral distance between the ends of grapple arms 32 decreases as they approach the grapple arm 3%. This arrangement of grapple arms 32 has the advantage of permitting grapple 28 to engage objects of widely varying size, and also tends to pull the object being engaged toward the center of the grapple with the result that the object being engaged is less likely to slip sideways out of the grapple.

Referring now to FIG. 4, the hydraulic circuit for operating fluid actuators 106 is shown in schematic form. A pump 116 which preferably is driven by the engine of the vehicle 10, pressurizes fluid drawn from a sump or reservoir 118 via a conduit 120. The pressurized fluid is directed to a control valve 122 by a conduit 124 which contains a pressure relief valve 126 vented back to the reservoir 118 by a conduit 128 to regulate the pressure in conduit 124. The front ends of cylinders 102 are connected in parallel by a conduit 13th which is connected to valve 122 via a conduit 132. Also, the rear ends of cylinders 102 are connected in parallel by a conduit 134 which is connected to valve 122 by a conduit 136. Connected to conduit 136 is an accumulator 138, the function of which will be explained shortly. The valve 122 also is connected to reservoir 118 by a conduit 146. The valve 122 is selectively actuatable between a grapple open position in which it communicates conduit 124 with conduit 132 and conduit 136 with conduit so that piston rods 104 move to the right as shown in FIG. 4 and pivot grapple arms 32 in a clockwise direction, as seen in FIGS. 1 and 2; a grapple closed position in which conduit 124 is connected to conduit 136 and conduit 132 is connected to conduit 140 with the result that pressure fluid is supplied to the back side of pistons 103, thus causing piston rods 104 to move to the left, as seen in FIG. 4, so that grapple arms 32 are pivoted in a counterclockwise direction, as viewed in FIGS. 1 and 2, to engage an object to be lifted; and a hold position in which

conduits

132 and 136 are in communication with neither conduits 124 nor conduit 140. When the grapple has engaged an object and the valve 122 is in the hold position the accumulator 138 serves to maintain substantially full pressure on pistons 103, since even a slight loss of pressure which otherwise would be possible through leakage around valve 122 and pistons 103 might cause the grapple to drop the object engaged thereby.

-While I have not described in detail the fluid circuitry associated with actuators 66 for pivoting grapple 28 about the ends of boom arms 20 and piston and cylinder actuators 24 for pivoting the boom arms 20 about point 22, it will be appreciated that these actuators are of the double-acting type, i.e., arranged to have fluid pressure communicated to either side of the piston to cause the piston rod to either extend or retract.

Actuators

66 and 24 are connected respectively to a source of pressure fluid and a fiuidreservoir by means of suitable fluid circuitry, including control valves conveniently located at the operators station for controlling the extension and retraction of the piston rods of the

actuators

66 and 24.

In operation, the grapple 28 is positioned so that the object to be engaged is disposed within the U-shaped opening between grapple arms 30 and $2. The object is then engaged by moving valve 122 to the grapple closed position, whereby grapple arms 32 are pivoted toward grapple arm 30 with the result that the object to be engaged is forcefully held between grapple

arms

30 and 32. It will be noted at this point that the parallel fluid connection between grapple arms 32 permits one of them to move a greater distance than the other, if necessary, to engage an object having an irregular shape. After the load is engaged, the valve 122 is actuated to its hold position so that grapple arms 32 will maintain forceful contact with the object engaged. Now the boom arms 20 can be actuated to lift the grapple, along with the load, slightly off the ground. With the load thus raised the tractor is used to transport the load to the desired location where the load may be redeposited upon the ground and the grapple released. Or the load may be deposited, for example, within a gondola-type railroad car by raising the boom arms to a height at which the grapple and the engaged object clears the side of the railroad car-including tilting the grapple partially back over the boom arms 20 by means of actuators 66 if necessary-then moving the tractor slightly forward to bring the load over the railroad car, at which point the boom arm actuators 24 and actuators 66, if used are actuated to cause the grapple to lower the load into the car. When the load is resting upon the bottom of the car the grapple arms 32 are actuated to release the load by moving valve 122 to the grapple release position. The grapple is then raised and the tractor it) is backed away from the railroad car.

The above-detailed description is illustrative only, and should not be construed as limiting the scope of my invention. The scope of my invention should be determined from the following appended claims when taken in view of the prior art.

I claim:

1. For use with a tractor having a pair of boom arms, a downwardly opening grapple comprising a laterally elongated grapple arm adapted to be pivotally connected to the boom arms, said elongated grapple arm including a pair of arcuate end plates disposed in laterally spaced apart relation and laterally extending brace means connecting said end plates, thus forming a unitary laterally elongated structure, a pair of laterally spaced apart arcuate grapple arms pivotally connected to said elongated grapple arm in confronting relation therewith, said grapple arms defining an inverted generally U-shaped opening therebetween, said pair of grapple arms being disposed in diverging relation relative to each other so that the axes about which they pivot are non-parallel, and means for actuating said pair of grapple arms pivotally relative to said elongated grapple arm, said means including a pair of fluid actuators connected respectively to said pair of grapple arms and connected in parallel to a source of pressure fluid.

2. A grapple comprising a laterally elongated grapple arm, said elongated grapple arm including a pair of laterally spaced apart end plates and a plurality of back- Wardly inclined brace members extending horizontally between and connecting said end plates, a pair of grapple arms pivotally connected to said elongated grapple arm in laterally spaced apart and confronting relation therewith so as to define an inverted generally U-shaped laterally elongated opening therebetween, said pair of grapple arms being disposed in diverging relation to each other so that the axes about which they pivot are nonparallel, and a pair of fluid motors for actuating respec tively said pair of grapple arms about their pivotal connections, said fluid motors being connected in parallel to a source of pressure fluid.

3. For use with a tractor having a pair of boom arms, a downwardly opening grapple comprising a laterally elongated grapple arm adapted to be pivotally connected to the boom arms, said elongated grapple arm including a pair of generally vertically disposed arcuate end plates disposed in laterally spaced apart relation and having serrations on the lower portion of the concave surfaces thereof, laterally extending, rearwardly inclined brace members connecting said end plates, said brace members having a sharp edge, and a laterally extending support plate connecting the upper ends of said end plates, thus forming with said end plates and brace members a unitary laterally elongated structure, a pair of generally vertically disposed, laterally spaced apart grapple arms pivotally mounted on said support plate in confronting relation with said elongated grapple arm and having serrations on the lower portion of the concave surfaces thereof, said grapple arms defining an inverted generally U-shaped opening therebetween, said pair of grapple arms being disposed in diverging relation relative to each other such that the included angle therebetween is substantially 20, and a pair of double-acting piston and cylinder type fluid motors connected between said pair of grapple arms and said elongated grapple arm for pivoting said pair of grapple arms relative to said elongated grapple arm, said fluid motors being connected in parallel with a source of fluid pressure.

4. A rock handling tractor vehicle comprising a body portion having a longitudinally extending horizontally disposed axis, a pair of forwardly extending boom arms located in symmetrical relation on opposite sides of the said axis, the said arms being pivoted at their rearward ends on the said body portion, a first pair of hydraulic actuators connected respectively between the said body portion and the said boom arms for raising and lowering the forward ends thereof, a downwardly opening grapple pivotally connected to the said forward ends of the boom arms, the said grapple including a pair of generally vertically disposed end plates located in laterally spaced apart relation and pivotally connected respectively to the said boom arms, the said end plates having curved forwardly extending portions at the tops thereof and serrations on the front surfaces thereof near the lower ends, a plurality of laterally extending brace members rigidly connected between the said end plates rearwardly of the said front surfaces, each of the said brace members presenting a forwardly disposed sharp edge and a slanted upwardly facin surface adjacent the said edge, and a laterally extending support plate rigidly connected between the said curved upper ends of the said end plates, the said end plates and brace members and support member forming a unitary transversely extending rear arm structure for the said grapple, a second pair of hydraulic actuators pivotally connected respectively between the said end plates and the said boom arms for pivoting the said rear grapple arm structure with respect to the said boom arms about a transverse horizontal axis, a pair of curved grapple arms pivotally mounted on the said support plate in generally vertically disposed laterally spaced apart relation and in confronting relation with the said rear grapple arm structure, the said pair of grapple arms having serrations on the rearward surfaces of the lower portions thereof, the said pair of grapple arms defining a generally U-shaped inverted opening between them and the said rear grapple arm structure, the said pair of grapple arms being disposed symmetrically with respect to the said longitudinal axis and in forwardly diverging relation relative to each other, each making an angle of approximately 10 with a vertically disposed plane through the said longitudinal axis, a third pair of hydraulic actuators connected respectively between the said pair of grapple arms and the said support plate for pivoting the said grapple arms toward and away from the said rear grapple arm structure, a source of pressurized hydraulic fluid carried by the said body portion, and means connecting the said third pair of hydraulic actuators in parallel to the said source of pressurized hydraulic fluid whereby the said pair of grapple arms may be operated simultaneously or individually if one of them is restrained from movement.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

4. A ROCK HANDLING TRACTOR VEHICLE COMPRISING A BODY PORTION HAVING A LONGITUDINALLY EXTENDING HORIZONTALLY DISPOSED AXIS, A PAIR OF FORWARDLY EXTENDING BOOM ARMS LOCATED IN SYMMETRICAL RELATION ON OPPOSITE SIDES OF THE SAID AXIS, THE SAID ARMS BEING PIVOTED AT THEIR REARWARD ENDS ON THE SAID BODY PORTION, A FIRST PAIR OF HYDRAULIC ACTUATORS CONNECTED RESPECTIVELY BETWEEN THE SAID BODY PORTION AND THE SAID BOOM ARMS FOR RAISING AND LOWERING THE FORWARD ENDS THEREOF, A DOWNWARDLY OPENING GRAPPLE PIVOTALLY CONNECTED TO THE SAID FORWARD ENDS OF THE BOOM ARMS, THE SAID GRAPPLE INCLUDING A PAIR OF GENERALLY VERTICALLY DISPOSED END PLATES LOCATED IN LATERALLY SPACED APART RELATION AND PIVOTALLY CONNECTED RESPECTIVELY TO THE SAID BOOM ARMS, THE SAID END PLATES HAVING CURVED FORWARDLY EXTENDING PORTIONS AT THE TOPS THEREOF AND SERRATIONS ON THE FRONT SURFACES THEREOF NEAR THE LOWER ENDS, A PLURALITY OF LATERALLY EXTENDING BRACE MEMBERS RIGIDLY CONNECTED BETWEEN THE SAID END PLATES REARWARDLY OF THE SAID FRONT SURFACES, EACH OF THE SAID BRACE MEMBERS PRESENTING A FORWARDLY DISPOSED SHARP EDGE AND A SLANTED UPWARDLY FACING SURFACE ADJACENT THE SAID EDGE, AND A LATERALLY EXTENDING SUPPORT PLATE RIGIDLY CONNECTED BETWEEN THE SAID CURVED UPPER ENDS OF THE SAID END PLATES, THE SAID END PLATES AND BRACE MEMBERS AND SUPPORT MEMBER FORMING A UNITARY TRANSVERSELY EXTENDING REAR ARM STRUCTURE FOR THE SAID GRAPPLE, A SECOND PAIR OF HYDRAULIC ACTUATORS PIVOTALLY CONNECTED RESPECTIVELY BETWEEN THE SAID END PLATES AND THE SAID BOOM ARMS FOR PIVOTING THE SAID REAR GRAPPLE ARM STRUCTURE WITH RESPECT TO THE SAID BOOM ARMS ABOUT A TRANSVERSE HORIZONTAL AXIS, A PAIR OF CURVED GRAPPLE ARMS PIVOTALLY MOUNTED ON THE SAID SUPPORT PLATE IN GENERALLY VERTICALLY DISPOSED LATERALLY SPACED APART RELATION AND IN CONFRONTING RELATION WITH THE SAID REAR GRAPPLE ARM STRUCTURE, THE SAID PAIR OF GRAPPLE ARMS HAVING SERRATIONS ON THE REARWARD SURFACES OF THE LOWER PORTIONS THEREOF, THE SAID PAIR OF GRAPPLE ARMS DEFINING A GENERALLY U-SHAPED INVERTED OPENING BETWEEN THEM AND THE SAID REAR GRAPPLE ARM STRUCTURE, THE SAID PAIR OF GRAPPLE ARMS BEING DISPOSED SYMMETRICALLY WITH RESPECT TO THE SAID LONGITUDINAL AXIS AND IN FORWARDLY DIVERGING RELATION RELATIVE TO EACH OTHER, EACH MAKING AN ANGLE OF APPROXIMATELY 10* WITH A VERTICALLY DISPOSED PLANE THROUGH THE SAID LONGITUDINAL AXIS, A THIRD PAIR OF HYDRAULIC ACTUATORS CONNECTED RESPECTIVELY BETWEEN THE SAID PAIR OF GRAPPLE ARMS AND THE SAID SUPPORT PLATE FOR PIVOTING THE SAID GRAPPLE ARMS TOWARD AND AWAY FROM THE SAID REAR GRAPPLE ARM STRUCTURE, A SOURCE OF PRESSURIZED HYDRAULIC FLUID CARRIED BY THE SAID BODY PORTION, AND MEANS CONNECTING THE SAID THIRD PAIR OF HYDRAULIC ACTUATORS IN PARALLEL TO THE SAID SOURCE OF PRESSURIZED HYDRAULIC FLUID WHEREBY THE SAID PAIR OF GRAPPLE ARMS MAY BE OPERATED SIMULTANEOUSLY OR INDIVIDUALLY IF ONE OF THEM IS RESTRAINED FROM MOVEMENT.