US3709550A

US3709550A - Automatic one line grapple

Info

Publication number: US3709550A
Application number: US00637565A
Authority: US
Inventors: J Mitchell
Original assignee: Individual
Current assignee: Individual
Priority date: 1967-05-10
Filing date: 1967-05-10
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

A grapple employed in the logging industry which includes a pair of tongs which are automatically opened and closed while being hung or supported from a single line or support and which is especially useful in highlead grapple yarding. The tongs are opened and closed in a single cycle of operation or a multiple cycle of operation which renders the grapple quite useful in turning or rotating a log. The tongs of the grapple are either supported from a supporting pin and linkage in which position the tongs are in closed or adjacent position or supported from a pin interconnecting the crossed tongs which pivots the tongs to an open position with the supporting function being sequential in response to movement of the grapple in a predetermined manner.

Description

United States Patent 1 1 Mitchell 1 51 Jan. 9, 1973 [54] AUTOMATIC ONE LINE GRAPPLE [76] Inventor: John H. Mitchell, 512 Westerly Drive, Aberdeen, Wash.

[22] Filed: May 10, 1967 [21] Appl. No.: 637,565

52] U.S.Cl. ..294/ll1,294/l18,2l2/84 51 Int. Cl ..B66c 1/00 [58] Field oiSearch ..294/110, 111,112,118, 119,

Primary Examiner-Harvey C. Hornsby Attorney-Clarence A. O'Brien and Harvey B. Jacobson [57] ABSTRACT A grapple employed in the logging industry which includes a pair of tongs which are automatically opened and closed while being hung or supported from a single line or support and which is especially useful in highlead grapple yarding. The tongs are opened and closed in a single cycle of operation or a multiple cycle of operation which renders the grapple quite useful in turning or rotating a log. The tongs of the grapple are either supported from a supporting pin and linkage in which position the tongs are in closed or adjacent position or supported from a pin interconnecting the crossed tongs which pivots the tongs to an open position with the supporting function being sequential in response to movement of the grapple in a predetermined manner.

7 Claims, 15 Drawing Figures PATENTEDJAN 9197s SHEET 1 BF 4 John H. Mi fche/l 50 INVENTOR.

BY mm; m

PATENTEDJAN 9 I975 John H. Mitchell INVENTOR.

WWW M AUTOMATIC ONE LINE GRAPPLE An object of the present invention is to provide an automatic one line grapple which will open and close while being supported or hung from a single line or single support and including a pair of tongs quite similar to the structure illustrated in my prior U.S. Pat. No. 3,245,712 issued Apr. 12, 1966 for POWER OPERATED GRAPPLE TONG. The grapple will either automatically open or close depending upon the position of the structural components so that the tongs are either supported from a pivot point interconnecting the links attached to the tongs or supported from a pivot pin interconnecting the crossed tong members.

Another object of the present invention is to provide a single line automatic grapple for highlead yarding employing either a single closing cycle or a multiple closing cycle with the multiple closing cycle being advantageous on some yarding or log loading jobs such as when it is desired to turn a log and also to eliminate opening of the grapple in the event the one line supporting structure is slackened accidentally or for some particular reason without causing the grapple to open.

Still another object of the present invention is to provide an automatic one line grapple for use in highlead yarding having a sky carriage and connecting link between the carriage and a swivel constructed in a manner to prevent tipping of the sky carriage block which could possibly cause binding in the telescoping action of the grapple thus preventing it from cycling properly.

Still another important object of the present invention is to provide an automatic one line grapple which is simple in construction, easy to use and renders the logging operation much safer and saves considerable labor and time as compared with conventional methods of opening and closing grapples.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a side elevational view of the automatic one line grapple of the present invention employed in a highlead yarding operation in which the tongs are illustrated in closed position;

FIG. 2 is an elevational view similar to FIG. 1 but with the tongs in their open position;

FIG. 3 is a detailed view illustrating the association of the cable with the pivot connection between the crossed tong members;

FIG. 4 is a vertical sectional view of the grapple illustrating the relationship of components thereof;

FIG. 5 is a vertical sectional view generally perpendicular to the sectional view of FIG. 4 illustrating further structural details of the grapple;

FIG. 6 is a fragmental sectional view illustrating the position of the automatic pivot arm as it lowers from the position of FIG. 5 to swing the pivot arm so that the support pin thereon will not engage the cycle stop;

FIG. 7 is a view similar to FIG. 6 but illustrating the position of the pivot arm as it is moved upwardly beyond the cycle stop and in which the pivot pin between the crossed tongs is supported from the cable;

. engagement with the cycle stop for closing the tongs;

FIG. 9 is a detailed sectional view taken substantially upon a plane passing along section line 9-9 of FIG. 6

illustrating the structural relationship of the components thereof; I

FIG. 10 is a transverse, sectional view taken substantially upon a plane passing along section line l010 of FIG. 6 illustrating further structural details of the components; 3

FIG. 11 is a transverse, sectional view taken substantially upon a plane passing along section line 11-11 of FIG. 7 illustrating further structural relationships of the components;

FIG. 12 is a detailed sectional view illustrating the swivel construction and the connection with the sky carriage;

FIG. 13 is a sectional view, with portions in elevation illustrating an embodiment of the invention employing a multiple cycling arrangement;

FIG. 14 is a fragmental sectional view illustrating the position of the pivot arm in the first cycle in engagement with the closing cycle stop and illustrating the path of movement of the arm and the closing pin thereon; and

FIG. 15 is a sectional view similar to FIG. 14 but illustrating the movement of the pivot arm after it leaves the second cycle of engagement with the closing cycle stop.

Referring now specifically to the drawings, the automatic single line grapple comprising the present invention is generally designated by the numeral 20 and is illustrated in a highleadyarding operation employing the usual sky carriage line 22 receiving a sky carriage 24 that is in supporting engagement with a special connecting link 26 having one side thereof connected to a main line 28 and the other side thereof connected to an out haul line 30. These lines and the association of the sky carriage and connectorflink 26 is known except that the connector link 26 is of special construction for a purpose described hereinafter.

Supported from the connector link 26 is a vertical shaft 32 having a swivel connection 34 at its upper end to the connecting link 26 and extending slidably through a bushing 36 in the upper end 38 of a housing generally designated by the numeral 40 and including a pair of substantially parallel side plates 42 which are perpendicular to the top plate 38 and the bushing 36 is of the sleeve type with the axis thereof being generally centrally between the side plates 42. I s

Extending between the lower ends of the plates 42 is a supporting pin or bolt 44 which supports a tongassembly generally designated by the numeral 46 and which includes a pair of

crossed tong members

48 and 50 which have

arm portions

52 and 54 on one side of a pivot bolt or pin 56 which interconnects pivotally the

crossed tongs

48 and 50. The other ends of the

tong members

48 and 50 are inwardly curved as at 58 and 60 and are provided with a pluralityof teeth 62 on the inner surface thereof for gripping engagement with a log 64. The tong assembly 46 is substantially the same as that disclosed in my prior U.S. Pat. No. 3,245,712. Connected to the

arm portions

52 and 54 is a pair of

links

66 and 68 connected thereto by pivot pins or

bolts

70 and 72 respectively with the

links

66 and 68 being supported from the support bolt 44. When the tong assembly 46 is supported freely from the support bolt 44 and there is nothing hindering or preventing the downward movement of the pivot pin or bolt 56, the

tong members

48 and 50 will move towards each other into clamping position or engagement with the log 64 or to the dotted line position as illustrated in FIG. 2.

Mounted on the pivot pin or bolt 56 which forms a center pivot for the tong members 48 and S is the sleeve or bushing 74 having a smooth exterior surface receiving a cable or line 76 which passes under the bushing or sleeve 74 and extends upwardly from both sides thereof. A connecting bar 78 is received on the two portions of the cable 76 extending upwardly from the sleeve 74 by virtue of the cable extending through passages 80 therein and being secured in place by setscrews 82. The connecting bar 78 holds the cable 76 in place in relation to the center pivot 56 and the sleeve or bushing 74 thereon and retains the cable 76 in a stiffened condition so that it will be retained in position in relation to the other components of the grapple and generally disposed between the plates 42.

The free ends of the cable 76 extend up through a pair of spaced apertures 84 in a plate 86 which extends between the plates 42 of the housing 40 but is not connected thereto. The center part of the plate 86 receives the lower end of the shaft 32 therethrough and is rigidly fixed thereto as by welding 88. The upper ends or free ends of the cable 76 above the plate 86 is provided with a stop 90 in the form of a ferrule or the like on each free end of the cable 76 which limits the upward movement of the plate 86 in relation to the cable 76 inasmuch as the stops 90 will not pass through the apertures 84 thus coming into engagement with the plate. When this condition occurs, the tong assembly 46 will then be supported from the center pivot point 56 rather than from the pivot bolt 44 thus causing the

tong members

48 and 50 to move to the open position illustrated in solid line in FIG. 2.

In order for the shaft 32 to be connected to the housing 40, a stop 92 is provided on each of the side plates 42 on the inner surface thereof. The stop 92 is provided with a downwardly opening notch or recess 94 in the lower surface thereof and a downwardly and outwardly inclined surface 96 on one edge thereof and a downwardlyinclined surface 98 on the opposite side thereof which is substantially straight but inclines slightly to the left as illustrated in FIGS. 6-8 while the surface 96 is sloped substantially to the left and down as illustrated in FIGS. 6-8. Disposed below each of the closing stops 92 is a lower pivot arm positioner 100 attached to each of the plates 42 on the inner surface thereof. The upper surface of the lower pivot arm positioner is provided with a pair of

arcuate recesses

102 and 104 separated by an upwardly extending projection or peak 106 which is inclined slightly to the left and generally is in alignment with the notch with the lower left corner of the notch being to the left of the peak 106 and the lower right corner of the notch 94 being to the right of the peak 106. The arcuate recess 102 has a portion thereof substantially straight as designated by numeral 108 which is upwardly and outwardly inclined to form a cam surface for positioning the,pivot arm during the cycling movement thereof.

The lower end of the shaft 32 is bifurcated asat 110 and pivotally receives the upper end of a pivot arm 112 therein which is pivoted to the lower end of the shaft 32 by a pivot pin 114. The pivot arm 112 is relatively narrow and is disposed generally centrally between and parallel to the side plates 42. At the lower end of the pivot arm 1 12, there is provided a rigid transversely extending pivot arm pin 1 16 which is welded or otherwise rigidly fixed to the lower end of the pivot arm 1 12 and which extends laterally outwardly to both sides thereof towards the side plates 42 and terminating adjacent the side plates 42 in a manner to enable swinging and vertical movement of the transverse pin 116 between the side plates 42.

The upper end of the pivot arm 112 is provided with a plurality of notches 118 which as illustrated in FIGS. 5-8 are three in number for a single cycle operation. The notches 118 are engaged by a plunger 120 which has a rounded and more or less pointed lower nose 122 for engaging the notches 118 and securing the pivot arm 112 in adjusted pivoted position. The plunger 120 includes a shank 124 which extends axially upwardly into a counterbore 126 in the lower end of the shaft 32. Surrounding the shank 124 is a coil compression spring 128 which has the upper end thereof engaging the closed end of the counterbore 126 and the lower end thereof engaging the shoulder defined by the junction between the shank 124 and the plunger 120 thus spring biasing the nose 122 of the plunger 120 into engagement with the notches 118 but enabling pivotal movement of the arm 112 if the resistance to said pivotal movement caused by the plunger 120 and the spring 128 is overcome in which event the spring will be compressed and the plunger moved upwardly so that it will move from one notch to the next. 9

Also, each of the plates 42 is provided with an upwardly and inwardly inclined guide 130 having an inwardly curved upper end portion l32 for scrving'to return the pivot arm 112 to an initial position after it has proceeded through its cycles of movement.

FIG. 5 illustrates the position of the pivot arm 112 in which the tong assembly 46 is in the position illustrated in FIG. 1 for grasping a log 64 by virtue of the load being lifted to the shaft 32, the pivot pin 1 14, the pivot arm 112, the pin 116 and the stops 92 and thus to the side plates 42, support bolt 44,

links

66 and 68, pivot pins and 72 and the

tong members

48 and 50. When liftingforce is exerted on the pivot bolt 44, the pivot pins 70 and 72 will be urged towards each other thus closing the tong members in an obvious manner.

To open the

tong members

48 and 50, it is only necessary to lower the shaft 32 until the load carried by the tong assembly 46 has been released and the tong assembly is supported from the ground surface or the like. During continued downward movement of the shaft 32, the stop pin ll6 along with the pivot arm [l2 and plate 86 will move downwardly until such time as the pin 116 engages the recess l04 to the right of the partition or peak 106 which will cause the pin 116 and of course the pivot arm 112 to pivot to the right to the condition illustrated in FIG. 6 and during this pivotal movement, the plunger will become disengaged from the center notch 118 and become engaged with the notch at the right hand portion of the pivot arm 112 as illustrated in FIG. 6. Upon subsequent upward movement of the shaft 32, the pin 116 will not be reengaged with the notch 94 but rather will pass upwardly between the surface 98 on the stop 92 and the inner surface of the guide 130 and as the pin approaches the upper end of the guide 130 the inwardly curved surface 132 thereon will cause the arm 112 to pivot to the left as illustrated in FIG. 7 and swing the pin 116 to the left so that the plunger 120 will again be engaged with the center notch 118 and so that the pin 1 16 is to the left of the upper end of the top 92. During this upward movement of the shaft 32, the side plates 42 are stationary and as the plate 86 engages the stops on the cable 76, the tong assembly 46 will be supported from the center pivot 56 and, in fact, the center pivot 56 will move towards the bolt 44 thus moving the pivot pins 70 and 72 apart and opening the

tong members

48 and 50 in an obvious manner. In this condition, the tong assembly 46 is in open position.

Upon subsequent lowering of the shaft 32, the open tong assembly 46 will engage a log and slack in the lift line or continued downward movement of the shaft 32 will cause the shaft 32 to move downwardly in relation to the plates 42 which are then stationarily supported so that the pin 116 will engage the inclined surface 96 on the stop 92 and be cammed further to the left to the dotted line position illustrated in FIG. 8 and this causes the plunger to engage the left hand notch 118. Continued further downward movement of the pin 116 brings it into engagement with the cam surface 108 as illustrated in FIG. 8 at which time the pivot pin 116 and the pivot arm 112 are swung to the right against the surface 102 with the peak 106 limiting the movement to the right and in this condition, the plunger 120 will then be in the central notch 118. Then upon subsequent upward movement ofthe shaft 32, the pin 116 will move upwardly from engagement with the recess 102 into engagement with the notch 94 with the divergent surfaces of the notch 94 guiding the pin 116 into engagement therewith which returns the structure to the condition illustrated in FIG. 5 and completes a cycle of operation.

As illustrated in FIG. 10, the lift plate 86 is provided with notches 134 in the side edges thereof to enable the plate to move vertically in relation to the guide member and the stop 92. Also, the openings 84 therein are rounded at the upper and lower edges thereof to prevent chaffin'g or binding with the cable 76. Also, one of the tong members such as the tong member 50 is provided with a laterally extending stop 136 to limit the movement of the

tong members

48 and 50 towards each other as illustrated in FIG. 2.

FIGS. 13-15 illustrate an embodiment of the invention in which multiple lifting and lowering is provided for in order to complete a cycle of operation. In this embodiment of the invention, identical reference numerals are employed to identify identical structure. In this embodiment of the invention, the plate 86 is provided with lugs 140 thereon for receiving one end of a tension spring 142 having the other end thereof attached to a lug 144 on a lower plate 146 which is fixed to the side plates 42'. This assures that the plate 86' will be moved downwardly in relation to the plates 42' when the grapple is lowered. The plate 146 is also provided with openings 148 for receiving the opening cable 76. Also, in this construction, the pivot arm 112' includes two additional notches 118' in the upper end thereof for receiving the plunger 120. The lower end of the pivot arm 112 is provided with a transversely extending pin 116 for engagement with a lower arm positioner 150 and a stop 152 and a curved guide member 154. The lower arm positioner 150 includes three

recesses

156, 158 and 160 with the recess 156 having an entrance cam surface 162 and the three recesses are separated by a pair of peaks or

partition members

164 and 166.

The stop 112 is provided with a pair of downwardly opening

notches

168 and 170 which are more or less aligned with the

peaks

164 and 166 and the left surface of the stop 152 is inclined to form a cam surface as at .172 and the other surface of the stop 152 is spaced from the guide member 154 to form an entrance way 174 for the pin 116. The upper end of the guide 164 is curved laterally into a position to deflect the pin 116 to then move up into the notch 170 and still be engaged with the stop 152. To disengage the pin 116 from the stop 152, it must again be lowered in relation to the arm positioner 150 where it will engage the recess 160 and then pass up through the passageway 174 into engagement with the guide member 154 for deflection laterally to the left of the stop member 152 so that upon subsequent downward movement thereof, the pin 116 will engage the recess 156 after which it will come into contact with the notch 168 to complete the cycle of operation. This is advantageous in some installations to prevent accidental release of the grapple in the event the lift line or shaft is slackened and also is beneficial in some uses such as when turning a log so that two log handling or lifting operations-can be obtained before the grapple opens.

FlG. 12 illustrates the swivel structure 34 in which the shaft32 is provided with a reduced threaded end portion receiving a nut 182 thereon which engages a thrust ball bearing 184 on the upper surface thereof. The lower surface of the ball bearing 184 is engaged with a screw threaded collar or cap 186 screw threaded onto the tubular depending socket 188. A suitable setscrew 190 is provided for retaining the swivel assembly in assembled relation. The upper end of the socket 188 is bifurcated as at 192 and receives a pivot pin 194 therethrough and also receives a depending lug 196 which is integral with the connecting link 26. The lug 196 is provided with a slot 198' which receives the pin 194 and a flat lower edge 200 which will engage the corresponding flat upper edge of the socket member 188 to retain the connecting link and sky carriage 24 generally in alignment with the shaft 32 when the load has been removed therefrom. This construction enables the grapple structure to pivot about the pivot pin 194 only when it is under tension and the flat surface 200 is in contact with the swivel only when slack thus holding the sky carriage in an upright position. Thus, the connecting link 26 between the sky carriage and the swivel will prevent tipping of the sky carriage block which can cause binding in the telescoping action of the shaft 32 in relation to the housing.

While the grapple has been illustrated in use with a highlead yarding arrangement, it can also be employed with a single lift line attached to any suitable type of lifting equipment. The lift line would be attached to the shaft 32 immediately above the swivel structure. Also, if desired, a cover plate may be employed for the housing to keep mud, sticks, stones or the like out of the mechanism positioned within the hollow frame thus prolonging the effective and useful life of the grapple. Either gravity, springs or other structural devices may be employed for assuring movement of the movable plate when the device is in the untensioned condition and it is noted that this device completely eliminates any sheaves whichrnay cause line or cable wear.

By employing the single line grapple constituting the present invention, the necessity of providing a separate person to open and close the tong assembly has been eliminated and also, there has been eliminated the necessity of employing a second cable or other power means such as fluid pressure cylinders to open and close the tong assembly. With the present invention, the opening and closing of the tong assembly is completely automatic and is accomplished through a single line which also serves as the lift line as well as the line to automatically cause opening and closing of the grapple.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. An automatic one line grapple for logging or the like comprising a vertically disposed shaft having means thereon for connection with a single support, a frame movably supported from the shaft for relative vertical movement in relation thereto, a tong assembly attached to and depending from the frame for opening and closing in response to relative vertical movement between the frame and shaft, and means interconnecting the shaft and frame for sequentially locking the shaft to the frame to preclude relative vertical movement therebetween and releasing the shaft from the frame to permit relative vertical movement therebetween for opening and closing the tong assembly, said tong assembly including a pair of crossed tong members pivotally interconnected by a center pivot at the point of crossing thereof, a tension member having one portion thereof engaged with the center pivot, means connecting another portion of the tension member to the shaft for selectively supporting the tong members from the center pivot, a pair oflinks attached to the ends of the tong members disposed above the center pivot, and a support means connecting the upper ends of the links to the frame whereby support of the tong assembly from the support means on the frame -will cause the tong members to pivot towards each other about the center pivot whereby the tong members will be closed when the tong assembly is supported from the support means on the frame and support of the tong assembly from the center pivot will open the tong members, said tension member interconnecting the frame and tong assembly being in the form of a flexible cable having a central portion thereof extending under and engaged with the center pivot, enlarged stops on the free ends of said cable disposed within said frame, an apertured plate disposed within the frame and movable in relation thereto receiving the cable, for enabling movement of the plate in one direction on the cable for limiting movement of the plate in relation to the cable in the other direction when the plate engages the enlarged stops on the cable, said plate being fixed to the lower end of said shaft for movement therewith to support the center pivot of the tong assembly when the frame and shaft move vertically in relation to each other so that the effective length thereof is greater than the effective length of the shaft and cable thereby causing the tong members to pivot to an open position by supporting the tong members from the center pivot and permitting the frame and support means to move towards the center pivot.

2. The grapple as defined in claim 1 wherein said means interconnecting the shaft and frame also includes a closing stop rigidly fixed to said frame and including a downwardly opening notch in the lower surface thereof, a pivot arm pivotally mounted on the upper end to said shaft and including a laterally extending closing pin on the lower end thereof for engagement in the notch in the lower end of the closing stop so that upward movement of the shaft will cause corresponding upward movement of the frame to support the tong assembly from the support means, and a pivot arm positioner disposed on said frame below the closing stop and including at least one pair of cam surfaces facing the notch on the closing stop for positioning the pivot arm in a desired position in relation to the closing stop for aligning the pin with the notch or misaligning the pin in relation to the notch on the closing stop for selectively engaging the pivot arm and shaft connected thereto with the closing stop and frame.

3. The grapple as defined in claim 2 wherein said frame includes a guide member extending vertically therein and including a laterally'offset upper end for engaging the stop pin to pivot the pivot arm to an initial position after the pin has been released from the notch and pivoted to a position in misalignment with the notch in the closing stop, said closing stop including a cam surface on the upper surface thereof for engagement by the pin and pivoting the pivot arm to a position so that the pin will engage the first cam surface on the pivot arm positioner during downward movement of the shaft and pivot arm in relation to the frame thus pivoting the pin on the pivot arminto alignment with the notch so that the pin will engage the notch upon subsequent upward movement of the shaft and pivot arm in relation to the frame thereby supporting the frame from the shaft and supporting tong assembly from the frame at the support means at the lower end thereof thereby causing the tong assembly to close.

4. The grapple as defined in claim 3 wherein said closing stop includes a plurality of downwardly facing notches and said positioner includes more than two cam surfaces on the upper surface thereof for requiring a multiple cycle of movement of the pin on the pivot arm between the lower surface of the closing stop and the pivot arm positioner for providing a multiple cycle of operation to interconnect the shaft and frame and to disconnect the shaft and frame.

5. An automatic one line grapple for logging or the like comprising a vertically disposed shaft having means thereon for connection with a single support, a frame movably supported from the shaft for relative vertical movement in relation thereto, a tong assembly attached to the lower end of the frame for opening and closing in response to relative vertical movement between the frame and shaft, and means interconnecting the shaft and frame for sequentially locking the shaft to the frame to preclude relative vertical movement therebetween and releasing the shaft from the frame to permit relative vertical movement therebetween for opening and closing the tong assembly, said means forming the single support for the shaft including a swivel structure at the upper end of said shaft, a connecting link attached to the upper end of the swivel, and a sky carriage attached to the upper end of the connecting link, said connecting link including a depending lug provided with a vertical slot therein pivotally securing the swivel to the connecting link when a load is supported by the connecting link, said lug on the connecting link having a flat lower edge for engagement with he swivel when the connecting link is not supporting a load to prevent tilting of the connecting link and sky carriage in relation to the shaft to prevent interference with the telescoping action thereof in relation to the frame.

6. The grapple as defined in claim 1 wherein said center pivot between the crossed tong members includes a sleeve thereon, said tension member being in the form of a cable entrained over said sleeve, said sleeve being smooth thereby eliminating chaffing and jamming of the cable during pivotal movement of the tong members.

7. The grapple as defined in claim 1 wherein said shaft includes shiftable means on the lower end thereof in engagement with said frame, and means on the frame for engaging the shiftable means to position the shiftable means in position for selective lifting engagement with the frame at a position below the point of engagement between the shaft and tension member whereby the tension member will not support the center pivot of the tong members even when fully closed, the other position of the shiftable means permitting the shaft to move upwardly to engage and to operatively exert tension force on the tension member to support the tong members from the center pivot to open the same.

Claims

1. An automatic one line grapple for logging or the like comprising a vertically disposed shaft having means thereon for connection with a single support, a frame movably supported from the shaft for relative vertical movement in relation thereto, a tong assembly attached to and depending from the frame for opening and closing in response to relative vertical movement between the fraMe and shaft, and means interconnecting the shaft and frame for sequentially locking the shaft to the frame to preclude relative vertical movement therebetween and releasing the shaft from the frame to permit relative vertical movement therebetween for opening and closing the tong assembly, said tong assembly including a pair of crossed tong members pivotally interconnected by a center pivot at the point of crossing thereof, a tension member having one portion thereof engaged with the center pivot, means connecting another portion of the tension member to the shaft for selectively supporting the tong members from the center pivot, a pair of links attached to the ends of the tong members disposed above the center pivot, and a support means connecting the upper ends of the links to the frame whereby support of the tong assembly from the support means on the frame will cause the tong members to pivot towards each other about the center pivot whereby the tong members will be closed when the tong assembly is supported from the support means on the frame and support of the tong assembly from the center pivot will open the tong members, said tension member interconnecting the frame and tong assembly being in the form of a flexible cable having a central portion thereof extending under and engaged with the center pivot, enlarged stops on the free ends of said cable disposed within said frame, an apertured plate disposed within the frame and movable in relation thereto receiving the cable, for enabling movement of the plate in one direction on the cable for limiting movement of the plate in relation to the cable in the other direction when the plate engages the enlarged stops on the cable, said plate being fixed to the lower end of said shaft for movement therewith to support the center pivot of the tong assembly when the frame and shaft move vertically in relation to each other so that the effective length thereof is greater than the effective length of the shaft and cable thereby causing the tong members to pivot to an open position by supporting the tong members from the center pivot and permitting the frame and support means to move towards the center pivot.

3. The grapple as defined in claim 2 wherein said frame includes a guide member extending vertically therein and including a laterally offset upper end for engaging the stop pin to pivot the pivot arm to an initial position after the pin has been released from the notch and pivoted to a position in misalignment with the notch in the closing stop, said closing stop including a cam surface on the upper surface thereof for engagement by the pin and pivoting the pivot arm to a position so that the pin will engage the first cam surface on the pivot arm positioner during downward movement of the shaft and pivot arm in relation to the frame thus pivoting the pin on the pivot arm into alignment with the notch so that the pin will engage the notch upon subsequent upward movement of the shaft and pivot arm in relation to the frame thereby supporting the frame from the shaft and supporting tong assembly from the frame at the support means at the lower end thereof thereby causing the tong assembly to close.