US3722706A - Weight aligned grapple - Google Patents

Abstract

A grappling device which includes a powered, rotatable grapple for grasping elongated objects. The grapple is normally attached by a support to a logging vehicle such as a skidder. The support is a movably-mounted boom which is controlled by a pair of hydraulic cylinders for effecting vertical and sidewise movement of the boom. The grapple comprises a weight-actuated cam as a rotative positioning means for self-alignment of a pair of coacting powered grapple jaws, an elongated bridge connecting said grapple jaws whereby generally uniform pressures are exerted upon grasped objects.

Description

[ 1 Mar. 27, 1973 Blonsky 154] WEIGHT-ALIGNED GRAPPLE [75] Inventor: Joseph E. Blonsky, Atlanta, Ga.

[73] Assignee: Westvaco Corporation, New York,

[22] Filed: Dec. 9, 1969 [21] Appl. No.: 883,653

Related US. Application Data [63] Continuation of Ser. No. 703,155, Feb. 5, 1968,

abandoned.

[52] US. Cl. ..212/44, 212/35, 294/88, 294/106, 214/138 [51] Int. Cl ..B66c 1/12 [58] Field of Search ..294/88,106,110,112,118, 294/82; 212/35, 55; 214/147, 147 G [56] References Cited UNITED STATES PATENTS 423,548 3/1890 Boyer ..294/111 2,639,048 5/1953 Glashaw... 2,672,230 3/1954 Jetzke ..294/82 2,672,364 3/1954 Ragland ..294/82 2,708,999 5/1955 2,755,946 7/1956 2,829,787 4/1958 Kalaus 212/35 3,011,651 12/1961 Mclntyre.. ..212/55 3,371,952 3/1968 Hunger.... .294/88 3,384,409 5/1968 Guinot ..294/106 FOREIGN PATENTS OR APPLICATIONS 996,785 6/1965 Great Britain ..294/88 Primary Examinerl-1arvey C. Hornsby Attorney-Ernest B. Lipscomb and Richard L. Schmalz ABSTRACT 8 Claims, 8 Drawing Figures PATENTEUMARZYIQYS SHEET 1 [1F 4 I NVENTOR Joseph E. Blonsky PATENTEUHARZYIQYS SHEET 30F 4 INVENTOR Joseph E. B/onsky AGE/VT PATENTEDHAR27 I973 SHEET LL 0F 4 INVENTOR Joseph E. B/ons/ry BY 0% M AGE/VT WEIGHT-ALIGNED GRAPPLE This application is a continuation of co-pending ap plication Ser. No. 703,155, filed Feb. 5, 1968 and now abandoned for Weight-Aligned Grappling Device.

BACKGROUND OF THE INVENTION This invention relates to load-handling devices. More specifically, this invention relates to grapple devices for grasping and handling of elongated objects such as logs and felled trees.

Grappling devices are particularly successful for grasping, aligning and skidding felled trees, for handling pulpwood as bundles of short logs and for moving other elongated objects such as pipes, rails and poles. Grappling devices generally comprise a grapple having at least two opposed jaws, at least one of which is pivotably from one end, which grasp an object and compress it from opposite sides whereby the object is held securely.

Examples of grapple devices which are adapted for handling elongated objects are described in the following U.S. Pat. Nos. 3,079,020, 3,089,726, 3,235,108, 3,275,173 and 3,362,550.

Many commercial grappling devices are used for handling pulpwood. Some grapples are cable operated and descend vertically upon a load, generally at the end of a movable boom. Others are hydraulically powered and are attached to the end of an articulated boom whereby the jaws of the grapple may be inserted into a load of logs at a desired angle. Grapples frequently must grasp the holes of singly felled trees and bring the trees into alignment with the holes of other felled trees and thus function well if mounted at the end of a boom. Many commercial grapples are mounted on the end of an articulated boom or A-frame support which is attached to a motor-powered vehicle such as a skidder. However, after a load of trees has been grasped by a skidder-mounted, boom-attached grapple the boom becomes a hindrance and is susceptible to damage during the skidding trip to a loading site. During the return trip while empty, the boom and grapple tend to swing and sway, whereby joints are worn excessively.

When an A-frame supported grapple of the prior art is used for transporting felled trees, the grapple is difficult to move sidewise and to rotate selectively into grasping position and difficult to control as to rotational position during skidding. Suspended attachment of the grapple to the apex of the A-frame, as by cables, enables the grapple to adapt readily to alignment of the boles but causes difficulties with penetration of grapple jaws beneath the holes. Hydraulic means for controlling rotation of the grapple are expensive, susceptible to damage, and difficult to control.

It is an object of this invention to provide a grapple device of simple design which includes a powered grapple having rotational capability while empty, whereby the jaws may readily adapt to the position of a load, and a weight-actuated biasing means for self-alignment of the grapple.

Another object of the invention is to provide a grapple device which includes a powered grapple having improved ground-penetration means for grasping elongated objects, such as felled trees, which have become partially embedded in the ground.

Still another object of this invention is to provide a grapple device having improved attachment means for mounting upon the rear of a skidder.

It is an additional object to provide a grapple device having a support means for the powered grapple which imparts limited capability for sidewise movement, whereby the grapple may engage a load without excessive manipulation of the skidder.

Further objects, features and advantages of this invention become apparent from the following disclosure when read in conjunction with the drawings.

I SUMMARY OF THE INVENTION The instant invention which fulfills these objectives comprises a grapple support means and a powered, rotatable grapple, having a biasing means for self alignment thereof, which is rigidly attached to the support means.

A rigid boom, articulated adjustable boom, fork'lift mast, or A-frame may be used as the support means for the powered, rotatable grapple of the invention. This support means may be attached to a stationary base or to a vehicle. The preferred embodiment for the grapple support means is intended for use with a vehicle, such as a skidder, and comprises an upwardly disposed boom having proximal and distal ends with relation to the vehicle, a boom support means for movably supporting the proximal end ofthe boom on the vehicle, a boom power means for upholding the boom and controlling the position of the distal end, and an attachment means which connects the powered grapple to the booms distal end while permitting swinging movements of the grapple in directions which are transverse to the boom and in line therewith. The preferred grapple support has the advantage of enabling the grapple to have limited, i.e., about 15, sidewise movement.

The powered, rotatable grapple comprises a generally vertical hanger rod rigidly attached to the grapple support means, a freewheeling means rigidly attached to the hanger rod, a generally horizontal and elongated bridge of rigid construction rigidly attached to the freewheeling means, a weight-actuated biasing means for self-alignment of the grapple attached to the freewheeling means, a pair of co-acting jawspivotably mounted on the bridge, and a grapple power means attached to the bridge and to the jaws for selectively pivoting the co-acting jaws into a grasping relationship. The grapple has the advantage of continually seeking to center itself while allowing easy rotative movement which is especially useful in making turns.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the powered, rotatable grapple and grapple support means of this invention mounted on the rear of a skidder.

FIG. 2 is a perspective view of the attachment means, which connects the grapple to the distal end of the boom, and of a portion of the bridge of the grapple.

FIG. 3 is a cross section of the attachment means, bridge, and weight-aligning means, looking in the direction of the arrows crossing the line 3-3 in FIG. 2, with the arched squeeze plate omitted.

FIG. 4 is a perspective view of the freewheeling means in exploded position so that the weight-actuated biasing means is clearly visible.

FIG. 5 is rear elevation view of the grapple in slightly opened position and of the closed jaws in phantom view.

in the direction of the arrows crossing the line 77 in t FIG. 5.

FIG. 8 is a fragmentary perspective view of another embodiment of the fulcrum joint.

DETAILED DESCRIPTION OF THE INVENTION Reference directions for a conventional motordriven vehicle are hereinafter used in describing a skidder 11 and the grapple device which comprises a grapple support means and a powered, rotatable grapple 50.

As shown in FIG. 1 for the preferred embodiment, the grapple support means comprises an upwardly disposed boom 20, a pressure joint 12 as the boom support means which movably supports the proximal end of boom 20, a pair of hydraulic cylinders 26 and associated piston rods 28 as the boom power means for upholding boom 20 and controlling the position of the distal end thereof, fulcrum joint 16 movably connecting the boom power means to boom 20, and suspension joint 13 as the attachment means at the distal end of boom 20 for suspending powered grapple 50 therefrom while permitting swinging movement of the grapple in directions which are transverse to the boom and in line therewith. Pressure joint 12, at the rear end of skidder ll, is at a relatively low elevation and along the skidders center line.

Sources of hydraulic power for hydraulic cylinders 26 are conventional hydraulic lines from a hydraulic pump and are not shown in the drawings. Hydraulic cylinders 26 are movably attached to the skidder at transversely spaced positions, above pressure joint 12, and converge toward boom 20. Cylinders 26 are attached by means of universal joints 14, 15 to opposite ends of transverse anchor beam 25. Cylinders 26, in addition to providing power to raise and lower boom 20, also supply power for moving boom from side-toside by actuating only one of the cylinders at a time. Sidewise movement of the grapple is determined by the stroke of piston rod 28, which normally gives a movement of approximate 15 side-to-side of distal end of the boom. Conventional means for supporting anchor beam are tension beams 123 and stiffeners 122. Hydraulic cylinders 26, piston rods 28, and boom 25 thus form a cantilevered A-frame which imparts an overturning type of moment to skidder 11, which is effectively counter-balanced by the skidders engine, when a load is picked up. Anchor beam 25 and tension beams 123 form a rigid framework which effectively resists sidewise thrusting and twisting forces.

Fulcrum joint 16 is attached to boom 20 at a position intermediate of the proximal and distal ends thereof. Boom 20 is bent downwardly approximately at dual fulcrum joint 16 in order to obtain additional rearward reach for boom 20 at an available stroke distance within cylinders 26. Boom 20 may be constructed in box form, with a channel beam forming top 22 and sides 23 to which a flat plate is welded to form bottom 24.

Pressure joint 12, as shown in FIG. 1, comprises a pair of plates 114 rigidly attached to sides 23 of boom 20 at the proximal end thereof, a thrust collar (not shown) is hingeably attached to plates 114 by pin 113, thrust pin 116 rigidly and perpendicularly attached to the thrust collar and attached to skidder 1 l. Thrust pin 116 should be generally aligned with the resultant of the weight of the loaded grappling device and of the turning force about fulcrum joint l6 when boom 20 is elevated.

As shown in FIGS. 2 and 3, suspension joint 13 is essentially a universal joint and comprises bracket 27 attached to the end of boom 20, pin 29 fitted to holes in the sides of bracket 27, collar 3!, reinforcing strip 34, shaft 32, straps 33 rigidly attached to hanger rod 36 and pin 35. Generally vertical hanger rod 36 of grapple 50 is axially aligned with shaft 32. Suspension joint 13 forms the attachment means which non-rotatably connects powered, rotatably grapple 50 to the distal end of boom 20 while permitting swinging movements of grapple 50 in directions which are transverse to the boom and in line therewith. If pin 35 and straps 33 are omitted (so that hanger rod 36 and shaft 32 can be an entity), grapple 50 is able only to move in line with the boom and is suited for use with booms having heel supports whereby logs are effectively lifted by grasping near one end thereof. Non-rotatable attachment of the grapple to the support means is essential, however, for operation of this invention. Two dimensional movement is available to suspension joint 13 by means of pins 2?, 35, but twisting of straps 33 around the axis of shaft 32 is not possible. Nevertheless, grapple S0 is able to twist freely about the axis of shaft 32 and hanger rod 36 because of an internal freewheeling means.

The freewheeling means, shown in a preferred embodimentin FIGS. 2 and 4, consists of a base attached to the bottom of hanger rod 36, and a bridge support rotatably supported by the base. This base is essentially a lateral protrusion from hanger rod 36 which permits free rotative movement of, and furnishes balanced support to, the bridge support. The remaining parts of grapple 50 are rigidly attached to and supported by the bridge support.

The grapple 50 comprises hanger rod 36 rigidly attached at its top to straps 33 and thus to the grapple support means, the two-part freewheeling means, a generally horizontal and elongated bridge 60 rigidly attached to and supported by the bridge support, a weight-actuated biasing means as part of the freewheelingmeans, a pair of co-acting jaws 51, 52 pivotably mounted on bridge 60, and a grapple power means attached to bridge 60 to jaws 51, 52.

As is clearly shown in FIG. 4 the weight-actuated biasing means is preferably a combination of co-acting cam and cam follower which are attached to and interposed between the base and the bridge support so that a rotative return force is created by the grapple itself upon the inclined faces of the cam. This rotative return force seeks to re-align the grapple after it has been rotatively displaced by relative rotation of the parts of the freewheeling means. When the grapple is empty, however, the rotative return force is relatively slight, and impact of jaws 51, 52 upon an obliquely aligned object can easily cause the empty grapple to freewheel in either rotative direction. The rotative return force nearly vanishes, moreover, when the grapple is momentarily supported by the obliquely aligned object. When the grapple is loaded and hanging freely, however, the rotative return force becomes considerably greater.

The cam may be attached to the base, and the cam follower may be attached to the bridge support, or vice versa, providing that they are in co-acting relationship. Many types of cams and cam followers are suitable for this purpose. For example, the top of the base could be a flat surface upon which a pair of elliptical wheels travel, these wheels being rotatably attached to the bottom of sleeve 76. Alternatively, the base could be reduced to rigid, protruding attachments for a pair of upwardly inclined levers, each lever having a terminal roller which moves within a scroll cam or covered crown cam in the lower part of a cylindrical bridge support thereabove.

The preferred embodiment for the weight-actuated biasing means however is a crown cam and a co-acting inverted crown cam follower. As shown in FIG. 4, this device is manufactured from a single cylinder by making inclined cuts therein, transversely to the cylinder axis, along a line of separation 75, forming two mating, generally vertical cylinders in stacked relationship and having a common axis which coincides with the axis of hanger rod 36, thereby combining the freewheeling means and the biasing means with a minimum of manufacturing difficulty. The crown cam is formed along the upper end of the lower base cylinder 73, and the coacting inverted crown cam, which functions as a cam follower having a contour which complements the contour of the crown cam, is formed along the lower end of the upper bridge supporting cylinder 72. Any relative rotation of these cylinders 72, 73 causes vertical separation thereof and consequent lifting of the entire grapple. This lifting energy creates the rotative return force needed for self alignment of the grapple. Rotation of bridge 60 is preferably restricted to less than 180 by stops 65 which are attached to the upper surface of top plate 61 so that they strike straps 33 after the bridge rotates about 45.

Generally horizontal bridge 60 described most clearly in FIGS. 2, 3 and 5 comprises top plate 61, side plates 62, stiffeners 68, arched squeeze plate 63, inner sleeve 76, and leverage arms 66. Side plates 62 are rigidly attached to inner sleeve 76 and to bridge supporting cylinder 72. Inner sleeve 76 rotatably encompasses hanger rod 36. Central openings in side plates 62 allow cylinders 72, 73 of the combined freewheeling means and biasing means to be of maximum size. Leverage arms 66, attached and aligned parallel to opposed side plates 62, are offset and project longitudinally from bridge 60 just beneath top plate 61. Leverage pin 41 attaches bracket 46 on each hydraulic cylinder 43 to each leverage arm 66.

The grapple power means comprises a source of hydraulic power, a pair of hydraulic cylinders 43, and associated pistion rods 45. The source of hydraulic power, including a conventional tank, pump, and hydraulic supply lines, is not shown in the drawings but supplies hydraulic power to each hydraulic cylinder 43 and each hydraulic cylinder 26. Each piston rod 45 is attached to ajaw 51, 52 by a pin 47.

Jaw pins 55 transversely penetrate reinforcing tabs 64 and side plates 62 near the lower corners thereof.

Jaws 51, 52, having adjacent bosses 42, 44 are equal so that each occupies one-half of the space between inner surfaces of side plates 62. Jaws, 51, 52 are adjacent to the inner surfaces of opposite side walls 62 so that each jaw is vertically aligned with the leverage arm 66 which is directly above, as shown in FIG. 2. Jaws 51, 52, being offset, slide past each other along a sliding plane between the jaws as the jaws close past the point of convergence of downwardly extending tips 53, 54 into the position shown in phantom in FIG. 5. Jaws 51, 52 have sharpened inner edges 56, 57, as shown in FIG. 6, which are immediately adjacent so that a couple with minimum moment arm is created when pressure is exerted against opposite sides of a log or bundle of elongated objects. The sharp edges 56, 57 hold a log securely against rearward dragging forces.

Each jaw tip 53, 54 of jaws 51, 52 is tapered away from the respective inner side, along the sliding plane between the jaws, as shown in FIG. 7, to form a point along the respective outer side, whereby the co-acting jaws 51, 52 are biased away from sliding contact when moving through soft, yielding material, such as earth.

The arched squeeze plate 63 is attached to and strengthens side plates 62 as shown in FIG. 5. When jaws 51,52 are fully closed, they form a sector having squeeze plate 63 as the arc thereof. If side plates 62 are lengthened, as is preferred, the distance between jaw pins 55 becomes equal to the distance along each of the sharpened edges 56, 57 from jaw pins 55 to the point of crossing of edges 56, 57, thereby forming a substantially equilateral triangle as the jaws are completely closed, whereby compression forces within a bundle of logs are transmitted uniformly and multi-laterally against all sides of a plurality of elongated objects which are grasped within the sector. Small logs are retained, in consequence, even though out of contact with edges 56, 57.

An alternative form of fulcrum joint 16 is shown in FIG. 8 which shows the joint as functionally a point connection with boom 20, as can be approximated with yokes 102, pivoting on a single pin 101 which is transversely attached to the upper surface of boom 20, slightly rearwardly to the bend therein.

When a load of logs or freshly felled trees are being dragged by a skidder with the grappling device of this invention, the combined actions of the freewheeling and biasing means permit turns to be made, because turning pressure is sufficient to overcome the rotative return force, but inhibit oscillatory and random rotative movements. When the grappling device of this invention is empty, the combined actions of the freewheeling and biasing means minimize random rotative movements of the grapple biasing it toward a selected center position, generally transverse to the direction of travel of skidder, and maintaining alignment of the jaws while grasping a load.

From the foregoing description, it is apparent that a simple but efficient grappling device has been provided for grasping one or a plurality of elongated objects. This grappling device can be attached to an elongated loading boom whereby lifting leverage can be exerted, in conjunction with a heel plate on the boom, for lifting entire logs, pipes or other elongated objects. If, as described hereinbefore, the attachment means is a suspension joint having the multiple-flexing but nonrotatory characteristics of a universal joint, the grappling device is not adapted for exertion of leverage but is well suited for dragging elongated objects or extended lifting and transporting of a bundle of short objects.

It is consequently to be understood that the invention is not to be limited to the embodiments as described and illustrated herein but is to be defined as to scope according to the claims which are hereinafter set forth.

lclaim:

1. A grappling device comprising: a grapple support having vertical and sidewise movements and a grapple rigidly attached to said grapple support, said grapple comprising;

a. a generally vertical hanger rod having an upper end rigidly attached to said grapple support and a lower end suspended therefrom,

b. a two-part freewheeling rotating means having'a first part rigidly attached to said hanger rod lower end,

c. a bridge support rigidly attached to the second part of said freewheeling means said bridge having a pair of outwardly extending bridge arms from said second freewheeling means whereby said bridge support may rotate about said vertical hanger rod,

d. said first and second part of said freewheeling means having adjacently disposed camming surfaces so-formed as to cause self-alignment of said grapple when unloaded such that the grapple is returned to its original position relative to said grapple support whenever it is disposed from such position,

e. a pair of co-acting jaws which are pivotably mounted respectively on opposite ends of said bridge arms, and

f. grapple power means pivotably attached to said bridge arms and to said grapple jaws for selectively opening and closing said jaws.

2. The grapple according to claim 1 wherein said freewheeling means first part has a crown cam formed integral with and surrounding said hanger rod lower end andsaid second part has an inverted crown cam co-acting with the positioned above said first part and mounted to rotate about said hanger rod, said freewheeling parts having camming surfaces being shaped such that when said second cam tends to move towards a selected central position whenever disposed off such central position.

3. The grapple according to claim 1 wherein said coacting jaws have sharpened inner edges along the sliding plane between said jaws, whereby a couple with a minimum moment arm is created when pressure is exerted against opposite sides of said elongated objects.

4. The co-acting jaws of claim 1 wherein the downward end of each jaw forms a tip, said tip being tapered from the respective inner side, along the sliding plane between the jaws, to form a point along the respective outer side, whereby the co-acting jaws are biased away from sliding contact when moving through a yieldable material.

5. The grapple according to claim 1 wherein the distance between said pivotable mounts forsaid co-acting jaws is approximately equal to the distance along each of said sharpened inner edges from the pivotable mount of the respective co-acting jaw to the point of crossing closed,

of said inner edges when said jaws are fully whereby approximately a 60 sector, having downwardly concave squeeze plate as the arc thereof, is formed at said point of crossing so that generally uniform pressures are exerted against all sides of a plurality of elongated object which are grasped within said sector.

The grapple support according to claim 1 wherein said grapple support is attached to a vehicle.

ing;

The grapple support according to claim 6 comprisan upwardly disposed boom having proximal and distal ends withrelation to said vehicle,

a boom support means attached to said vehicle, for movably supporting the proximal end of said boom,

. a boom power means attached to said vehicle and to said bottom, for upholding said boom and for providing side-to-side and vertical movement of said distal end, and

. means for connecting said grapple to said distal end while permitting movement of said grapple.

. A log handling vehicle comprising; a grapple support having one end mounted to swing on said vehicle and the opposite end free to move to various work positions,

. power means mounted on said vehicle and connected to said grapple support providing vertical and sidewise movement of said grapple support for positioning in said work positions,

. a vertical hanger rod having its upper end mounted on said grapple support working end and its lower end suspended therefrom,

. a first cam formed integral with and surrounding said hanger rod lower end and having a first camming surface on the upper portion,

. a second cam positioned above said first cam and f. a bridge support having opposite aligned horizontal arms extending outwardly from and formed integral with said second cam such that said bridge support and second cam rotate about said hanger rod,

. a pair of co-acting grapple jaws pivotedly mounted respectively on opposite ends of said bridge arms; and

. grapple power means pivotedly attached to said bridge arms and to said respective grapple jaw for the opening and closing thereof, said grapple jaws when loaded being effective to transfer the force of said load through said bridge support to said second cam and thereby cause said second cam to rotate towards said central position. I

Claims (8)

1. A grappling device comprising: a grapple support having vertical and sidewise movements and a grapple rigidly attached to said grapple support, said grapple comprising; a. a generally vertical hanger rod having an upper end rigidly attached to said grapple support and a lower end suspended therefrom, b. a two-part freewheeling rotating means having a first part rigidly attached to said hanger rod lower end, c. a bridge support rigidly attached to the second part of said freewheeling means said bridge having a pair of outwardly extending bridge arms from said second freewheeling means whereby said bridge support may rotate about said vertical hanger rod, d. said first and second part of said freewheeling means having adjacently disposed camming surfaces so-formed as to cause self-alignment of said grapple when unloaded such that the grapple is returned to its original position relative to said grapple support whenever it is disposed from such position, e. a pair of co-acting jaws which are pivotably mounted respectively on opposite ends of said bridge arms, and f. grapple power means pivotably attached to said bridge arms and to said grapple jaws for selectively opening and closing said jaws.

2. The grapple according to claim 1 wherein said freewheeling means first part has a crown cam formed integral with and surrounding said hanger rod lower end and said second part has an inverted crown cam co-acting with the positioned above said first part and mounted to rotate about said hanger rod, said freewheeling parts having camming surfaces being shaped such that when said second cam tends to move towards a selected central position whenever disposed off such central position.

3. The grapple according to claim 1 wherein said co-acting jaws have sharpened inner edges along the sliding plane between said jaws, whereby a couple with a minimum moment arm is created when pressure is exerted against opposite sides of said elongated objects.

4. The co-acting jaws of claim 1 wherein the downward end of each jaw forms a tip, said tip being tapered from the respective inner side, along the sliding plane between the jaws, to form a point along the respective outer side, whereby the co-acting jaws are biased away from sliding contact when moving through a yieldaBle material.

5. The grapple according to claim 1 wherein the distance between said pivotable mounts for said co-acting jaws is approximately equal to the distance along each of said sharpened inner edges from the pivotable mount of the respective co-acting jaw to the point of crossing of said inner edges when said jaws are fully closed, whereby approximately a 60* sector, having downwardly concave squeeze plate as the arc thereof, is formed at said point of crossing so that generally uniform pressures are exerted against all sides of a plurality of elongated object which are grasped within said sector.

6. The grapple support according to claim 1 wherein said grapple support is attached to a vehicle.

7. The grapple support according to claim 6 comprising; a. an upwardly disposed boom having proximal and distal ends with relation to said vehicle, b. a boom support means attached to said vehicle, for movably supporting the proximal end of said boom, c. a boom power means attached to said vehicle and to said bottom, for upholding said boom and for providing side-to-side and vertical movement of said distal end, and d. means for connecting said grapple to said distal end while permitting movement of said grapple.

8. A log handling vehicle comprising; a. a grapple support having one end mounted to swing on said vehicle and the opposite end free to move to various work positions, b. power means mounted on said vehicle and connected to said grapple support providing vertical and sidewise movement of said grapple support for positioning in said work positions, c. a vertical hanger rod having its upper end mounted on said grapple support working end and its lower end suspended therefrom, d. a first cam formed integral with and surrounding said hanger rod lower end and having a first camming surface on the upper portion, e. a second cam positioned above said first cam and mounted to rotate around said hanger rod and having a second camming surface on its lower portion disposed opposite said first camming surface, said first and second camming surfaces being shaped such that when said second is forced downwardly toward said first cam said second cam tends to rotate towards a selected central position whenever disposed off such central position, f. a bridge support having opposite aligned horizontal arms extending outwardly from and formed integral with said second cam such that said bridge support and second cam rotate about said hanger rod, g. a pair of co-acting grapple jaws pivotedly mounted respectively on opposite ends of said bridge arms; and h. grapple power means pivotedly attached to said bridge arms and to said respective grapple jaw for the opening and closing thereof, said grapple jaws when loaded being effective to transfer the force of said load through said bridge support to said second cam and thereby cause said second cam to rotate towards said central position.

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