US2761727A - Logging tongs and means for opening and closing same - Google Patents

Description

Sept. 4, 1956 D. MOORE ,76 7 7 LOGGING TONGS AND MEANS FOR OPENING AND CLOSING SAME.

Filed June 14, 1954 IN VEN TOR. Dam/arc! Moore United StatesPatent 4 Claims. or. 294-118 The present invention relates to improvements in a device for opening and closing logging tongs.

In present day logging operations, the cut timber is oftenlifted and carried by tongs suspended by a cable from a crane or other lifting device. The tongs have inwardly directed spikes thereon which bite into the logs and secure them so that they may be lifted and carried. The difficulty encountered in the use of such devices is that the tongs do not open and release the logs automatically. When a log is lifted with a pair of tongs the spikes are imbedded in the wood firmly enough that they remain stuck until jarred loose. The present practice is 1 to have a man at the releasing point toperform the task of jerking the tongs free of the logs, or to allow the logs to fall the last foot or two to the releasing point and jar the spikes loose by the impact. Both of these methods are impractical since they involve either additional man-- power or possible damage to the loading surface where- Q on the logs fall. This is particularly true where logs are loaded on trucks or docks.

It is the principal purpose of my invention to provide a pair of tongs which may be opened and closed bythe. operator of the crane or jammer without the aid of another man and without the necessity of allowing the logs to fall to the loading surface.

My invention comprises a pair of tongelements pivotal near the upper ends and having upper arm portions extending beyond the pivot. Each of the upper arms has a clevis attached thereto intermediate the pivot and the free end. A supporting cable is attached to the clevises. Links are attached to the free ends of the arm portions and extend upwardly. A guide bar connects the upper ends of the links. The supporting cable extends upwardly through the guide bar to the boom; of the crane or jammer. A weight or hammer is slidably mounted on the supporting cable above the guide bar and is adapted to be dropped on the guide bar to open the tongs.

The nature and advantages of my invention will appear more fully from the following description and the accompanying drawings wherein a preferred form of the invention is shown. The drawings and description are illustrative only and are not intended to limit the invention except insofar as it is limited by the claims.

In the drawings:

Figure 1 is a front view of a pair of tongs embodying my invention in position to carry a log;

Figure 2 is a view similar to Figure 1 except showing the tongs open;

Figure 3 is a view of a pair of tongs embodying my invention in closed position, and illustrating the means by which the tongs are held from closing too far;

Figure 4 is an enlarged partial side view of the device; and

Figure 5 is an enlarged plan View of the device looking in the direction of the arrows 5--5 of Figure 1.

Referring now tothe drawings, my invention is shown in coordination with a pair oflogging tong elements 10 and 11. Thetong elements 10 and 11 are pivoted at 12 Patented Sept. 4, 1956 and have inwardly directedspikes 13 and 14 at their lower ends. Thetong elements 10 and 11 haveupper arms 15 and 16 which extend upward beyond thepivot 12 for a substantial distance. Eacharm 15 or 16 has aclevis member 17 pivoted thereto intermediate its ends. Theclevis members 17 pass through aloop 18 in a supportingcable 19 to support thetongs 10 and 11. Thecable 19 extends upwardly to a sheave mounted on a crane boom and then down to a power winch. With this construction, the weight of thetong elements 10 and 11 causes them to grip objects placed between their jaws automatically. When the tongs are placed around a log such as is shown in Figure 1, their weight causes them to close about the log, and when thecable 19 is drawn taut, the weight of the log itself causes thespikes 13 and 14 to' bite into the wood and secure the log for movement.

When it is desired to release the log, the cable is allowed to slacken, thus releasing the tension on thetong elements 10 and 11. However, thespikes 13 and 14 remain imbedded in the wood, so that when the cable is drawn up to remove the tongs, the log will again be gripped. It is necessary, therefore, to include some means by which thetong elements 10 and 11 may be spread to withdraw thespikes 13 and 14 from the wood. This frequently is done'by raising the log from its resting place with the tongs and then allowing it to fall back, thus jarring the spikes loose. However, this procedure is undesirable when the resting place for the log is a truck bed or dock since repeated blows of the falling logs damage the structure. In the event that the resting place of the log is on a pile of other logs, this technique could result in dislodgingthe pile. In order to open the tongs without allowing the log to drop, or without involving additional manpower to jerk ice the spikes loose, I provide a mechanism on thetongs 10 and 11 which may be operated by the crane operator to release the tongs fromthe log when desired.

To accomplish this result, I providelinks 20 and 21 near the free ends of thearms 15 and 16. Thelinks 211 and 21 are each comprised of two bars such as 20a and 20b shown in Figure 4. a Thebars 20a and 2% are positioned on either side of thearm 16 and apivot pin 22 is provided to pivotally secure them to thearm 16. Asimilar pin 23 pivots thelinks 21a and 21b to thearm 15. The upper ends of thelinks 20 and 21 are secured together by aguide bar 24 andpivot pins 25 at each end of theguide bar 24. Theguide bar 24 has acentral aperture 26 to pass thecable 19.

Themembers 15, 1 6, 20, 21 and 24 form a pentagon having pivotal connections at each of its five verticles. If theguide bar 24 is forced downward as in Figure 2, thearms 15 and 16 will be spread, thus spreading thetong elements 10 and 11. To perform this action, aWeight 27 is provided above theguide bar 24. Theweight 27 has acentral aperture 28 through which the cable 1h extends, so that theweight 27 may slide up and down on thecable 19. Alead cable 29 is attached to theweight 27 and extends upward beside thecable 1? to a sheave on the crane and then to the operators platform.

When theweight 27 is drawn upon thecable 19 so that it is not resting on theguide bar 24, the Weight of thetong elements 10 and 11 causes them to swing together. Thearms 15 and 16 also swing together. If thesearms 15 and 16 are allowed to close far enough so that the distance between thepivot pins 22 and 23 is less than the length of theguide bar 24, the links 21) and 21 will be placed in such position that downward pressure on thebar 24 will fail to open the tongs. To prevent this from occurring, I provideshort extensions 30 on thearms 15 and 16 beyond thepivots 22 and 23.Transverse stop pins 31 are attached to the ends of theextensions 30. When thearms 15 and 16 close far enough so that thelinks 20 and 21 are nearly in a vertical position, thestop pins 31 strike thelinks 20 and 21 and hold thearms 15 and 16 from closing further. Figure 3 shows the device in such a position.

The operation of the device is very simple. 'The operator merely allows theweight 27 to rest upon thebar 24, thus holding the tongs 1.0 and 11 open. When the tongs are positioned around a log, he draws theweight 27 up and the tongs and 11 close on the log. When it is desired to release the log, the operator allows thecable 19 to slacken enough that there is no tension on thetongs 10 and 1.1. Then he drops'theweight 27 on theguide bar 24. This forces the spikeslS and 14 out of the log and opens the tongs to receive the next log.

It is believed that the nature and advantages of my invention appear fully from the foregoing description and the accompanying drawings.

Having thus described my invention, 1 claim:

1. A device for lifting and carryinglogs or the like comprising a pair of curved'tong elements pivotally connected near their upper ends and crossing each other at the pivotal connection, an arm portion on each tong element extending upwardly beyond the pivotal connection, a connecting member attached to each arm portion intermediate the pivotal connection and the free end, a supporting cable attached to the connecting members, a link pivotally attached to the free end of each armportion and extending upwardly, a guide bar pivoted to and connecting the upper ends of the links, the supporting cable extending through the guide bar, a'hammer member slidable on the cable above the guide bar so that it may be dropped on the guide bar and links to spread the tongs, and means to lift said hammer member.

2. A device for lifting and carrying logs or the like comprising a pair of curved-tong elements pivotally connected near their upper ends and crossing each other at the pivotal connection, an arm portion ,on each tong element extending upwardly beyond ,the pivotal connection, a connecting member attached to each arm portion intermediate the pivotal connection and the free end, a supporting cable attached to the connecting members, a link pivotally attached to the free end of eacharm portion and extending upwardly, a guide'bar pivoted {to and connecting the upper ends of the links, the supporting cable extending through the guide bar, extensions on the arm portions adjacent the links, stop-members on the extensions whereby to engage the links as the upper ends of the arm portions approach each other and thereby position the links upright, a hammer member slidable on the cable above the guide bar so that it may be dropped on the guide bar and links to spread the tongs, and means to lift said hammermember.

3. A device for lifting and .carryinglogs ,or ,thelike comprising a pair of curved tong elements pivotally connected near their upper ends and crossing each other at the pivotal connection, an arm portion on each tong element extending upwardly beyond the pivotal connection, a clevis pivotally attached to each arm portion intermediate the pivotal connection .and the free end, a supporting cable having a loop formed in its end, said loop passing through each clevis and securing ittothe cable, a pair of links positioned at the free end of each arm portion, said links beingpivotedto each side of the arm and extending upwardly, a guide 'bar positioned above the armportions and being .pivotallyconnectedat each end to the upper ends of the pairsoflinks, said guide bar having an aperture therein intermediate its ends, the supporting cable passing through said aperture, a Weight slidable on the supporting cable above the guide bar so that it may be dropped on the guide bar and links to spread the tongs, and means connecte'd to the weight to lift it from the guide bar.

4. A device 'for lifting and carrying logs on the like comprising a pair of curved tong elements pivotally connected near their upper ends and crossing each other at the pivotal connection, an arm portion .on each tong element extendingupwardlyibeyond the pivotal connection, a clevis pivotally attached to each arm portion intermediate the pivotal connection and the free end, a

supporting cable having a loop formed in its end, said loop passing through each clevis and securing it to the cable, apair of links positioned at the free end of each arm portion, said links being pivoted to each side of the arm-and extending upwardly, a guide bar;positioned.above the arm portions and being pivotally connected at each end to the upper ends of the pairs of links, said guide ban-having an aperture therein intermediate its ends, the supporting cable passing through said aperture, extensions on the arm-portionsadjacent the links, stop members attached to the ends of the extensions, said stop members each extendingtransversely of the pairs of links whereby-to en-gage thelinks as the upper ends of the arm portions approach each other and thereby position the links upright, a weight slidable on the supporting cable above the guide bar so that -it may be dropped on the guide bar and'links to spreadthe tongs, and means connected tothe weight to lift it from the guide bar.

References :Cited in the file of this patent UNITED STATES PATENTS 2,494,010 'Spann, Ian. .10, 1950 FOREIGN .PATENTS 206,391 Germany Feb.'2, 1909

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