US2815242A - Counterbalanced and weight operated tongs - Google Patents

Description

Dec. 3, 1957 1.1-: ROY T. KENYON 2,815,242

COUNTERBALANCED AND WEIGHT OPERATED TONGS Filed NOV. 8, 1955 IN VEN TOR.

/5/95 Z'Aiwm/v United States Patent COUNTERBALAN CED AND WEIGHT OPERATED TONGS LeRoy T. Kenyon, Duluth, Minn.

Application November 8, 1955, Serial No. 545,715

7 Claims. (Cl. 294-110) This invention relates to apparatus for grasping and picking up a load and more specifically relates to counterbalanced and weight operated jaws.

Devices for picking up heavy loads such as loaded warehouse skids, ingots and castings, life rafts and boats and other similar loads have, in the past, taken many different forms. A disadvantage common to substantially all previous load pickup devices has been that auxiliary controls in the form of additional cables operated from a control station have been necessary in order to close and reopen the jaws. Of course such controls make the pickup device substantially more expensive and necessitate that a highly experienced and highly paid operator be employed to use the pickup device. In most cases the load to be picked up must not be handled roughly, but on the other hand a slight additional weight applied to the top thereof would not be damaging to the articles to be picked up.

An object of my invention is to provide a new and improved article-grasping and pickup device of simple and inexpensive construction and operation which will grasp an article by merely lowering the device thereon.

Another object of my invention is the provision of a novel device which will, when lowered to an article to be picked up, grasp the article without the assistance of auxiliary controls or manual operation of the jaws which grasp the article.

A further object of my invention is to provide an improved article pickup device of the type having swingable jaws which are normally counterbalanced to open position by a weight suspended therebetween and which jaws, when lowered over an article, cause the weight to be engaged and be supported by the article to close and securely grasp said article.

These and other objects and advantages of my invention will more fully appear from the following description made in connection with the accompany drawings wherein like reference characters refer to the same parts throughout the several views and in which:

Fig. l is a perspective view of the invention shown in open position;

Fig. 2 is a front elevation view of the invention and showing a dotted position thereof when shifted to articlegrasping position;

Fig. 3 is a detail front elevation view showing a modified form of a portion of the invention; and

Figs. 4 and 5 are both front elevation views of the invention showing it adjusted for picking up loads of different natures.

One embodiment of the present invention is shown in the accompanying drawings. A pair of jaws indicated in general by numerals and 11 are constructed for cooperating with each other in picking up a load or article. In the form shown the jaws 10 and 11 are formed of a plurality of tines 12 and 13 respectively. The tines are curved in generally semi-orbiculate shape and have lower end portions which extend generally inwardly toward each other. The jaws 10 and 11 could as well take other Rte forms and be formed of solid metal plates if desired and may, in addition, have the ends of the jaws enclosed so as to form a substantially closed bucket when the jaws are shifted toward each other.

Yokes 14 and 15 are formed in the upper end portions of the jaws 10 and 11 to define enlarged openings therein. Means are provided for pivotally interconnecting the jaw upper end portions and in the form shown, such means include pins 16 and 17 which extend through suitably provided apertures in the side portions of the yokes 14 and 15. The pins 16 and 17 are positioned to maintain the openings defined by the yokes 14 and 15 in substantial vertical alignment when the jaw upper end portions are swung relative to each other about the pivots.

Means are provided for supporting the jaws 10 and 11 and connecting the same to a suitable depending support such as cable C. In the form shown, such means include a rigid support member 18 having an aperture 18a therein through which the cable C is extended and then secured backed upon itself by such means as clamp 19. A pair of elongated elements 20 and 21 are secured to the sup port member 18 at their upper end portions and are connected at their lower end portions to the upper extremities of the jaws 11 and 10 respectively. The upper end portions of the jaws 10 and 11 are provided with projecting lugs or arms 22 and 23 to which the flexible elements 20 and 21 are connected. In the form shown the elongated elements 20 and 21 comprise chains. The chains 20 and 21 are free to swing relative to the upper ends of the jaws 1t] and 11 and with respect to the support member 18.

Means are also provided for controlling the operation of the jaws 10 and 11 and for partially supporting the same. In the form shown such means include a pair of upwardly facing convex guides comprising sheaves 24 and 25 which are secured to and supported from the supporting member 18. A pair of elongated flexible elements 26 and 27 are respectively trained over the sheaves 24 and 25 and have opposite depending end portions. The outer end portions 26a and 27a of each of the flexible elements 26 and 27 are connected to the jaws 10 and 11 respectively intermediate the lower end portions thereof and the pivots 16 and 17. Suitable rings 28 and 29 may be afiixed to the jaws 10 and 11 for securing the flexible elements 26 and 27 thereto. Means are provided in the outer end portions 26a and 27a of cables 26 and 27 for adjusting the lengths of the cables and in the form shown such means comprise releasable clamps 30 and 31 which secure the end of the cable back upon itself. These clamps may be loosened to allow the length of the cable 26 to be adjusted. The inner end portions 26b and 27b of cables 26 and 27 are both connected to a weight 32 for suspending the same. Weight 32 is positioned between the jaws 10 and 11 and below the openings defined by the jaw upper end portions. Weight 32 will extend into proximity with the lower end portions of jaws 10 and 11 and is shiftable upwardly through the openings defined in the jaw upper end portions.

In operation, as best seen in Fig. 2, the jaws 10 and 11 are normally maintained in open position by a downward force exerted by weight 32 on the inner end portions 26b and 27b of cables 26 and 27, causing an upward force to be exerted on the intermediate portions of jaws 10 and 11 causing the lower end portions of the jaws to operate and swing upwardly. A portion of the Weight of the jaws is carried by the cables 26 and 27 in this position. The remainder of the weight of the jaws is carried by the chains 20 and 21. When the jaws 10 and 11 are lowered by means of cable C into proximity with an article A to be picked up, the weight 32 will engage the article A and as the jaws 10 and 11 are lowered toward the article, substantially all the weight of weight 32 will be carried by the article. When the weight 32 no longer is carried entirely by the inner end portions 26b and 27b of cables 26 and 27, the jaws 10 and 11 are permitted to swing downwardly toward each other about the pivots 16 and 17. As the jaws are lowered further they will shift under an. outstanding portion of the article A to be picked up. When the weight 32 is supported by the article and not by the cables 26. and 27, the entire weight of the jaws 10 and 11 is supported by chains 20 and 21. The entire weight of the jaws 10 and 11 is thereby free to swing about the upper extremities thereof to which chains 20 and 21 are connected. This entire weight of jaws 10 and 11 causes the article A to be grasped with a very substantial force.

The cable C may thereafter be raised and the jaws 10 and 11 will retain their grasp on the article A so as to raise the article. Because of the unique shape of the lower end portions of the jaws l and 11, as best seen in Fig. 2, there is. substantially no force exerted on the jaws 10 and 11 by the article A tending to cause the jaws to operate and to reopen. The lower end portions of the jaws 10 and 11 extend nearly horizontally in supporting the article.

When the article is to be removed from the jaws, it will again be lowered to a suitable support such as a floor, and the weight 32 will be shifted off the article A into a position similar to dotted position B thereof. The weight 32 will thereupon exert a substantial downward force on the cables 26 and 27 and will cause the jaws 10 and 11 to swing outwardly and upwardly into open condition. It should be noted that the weight 32 may shift upwardly through the opening defined in the jaw upper end portions, and the opening therein is of such size that the weight 32 may be shifted toward either jaw or endwise of the jaw and outwardly through the open end thereof when the weight is to be removed from the article so as to reopen the jaws. In the form shown, the tines 12 and 13 are spaced from each other sufiiciently so that the weight 32 may pass therebetween.

As shown in Fig. 4 the invention is well adapted to picking up loaded warehouse skids. In Fig. 4 the lengths of cables 26 and 27 are adjusted so as to adapt the jaws for picking up loads having only a low heighth. In this form the weight 32 is permitted to hang downwardly a suflicient distance so as to engage the low-heighth load L on the skid and cause the jaws 10 and ll'to pass beneath the skid in order to pick it up.

In Fig. it will be seen that the cables 26 and 27 are adjusted toraise the weight 32 so as to adapt it for picking up high loads as on a skid.

In Fig. 3 a detail view is shown of a modified form of jaws applicable in the invention. It will be noted that in this form of the invention the jaws 40 and 41 have substantially straighter lower end portions and when swung together are substantially pear-shaped. This type of jaws is readily applicable to general use and is highly desirable in picking up loads of logs, life boats and the like.

It will be seen that I have provided a new and improved load pickup device which when lowered onto the article to be picked up, causes opposed jaws to grasp the article without the necessity of auxiliary control means to be operated from a remote location. The jaws need only be disposed on opposite sides of the article and then lowered to cause the weight to engage the article whereupon the jaws will, by their own weight, close upon or underneath the article.

It will, of course, be understood that various changes may be made in the form, detail, arrangement and proportion of the parts-without departing from the scope of my invention which consists of the matter described herein and set forth in the appended claims.

What I claim is:

1. A load pickup device for attachment to the end of a depending support, said device comprising a pair of semi-orbiculate jaws having free lower end portions and having upper end portions, said jaws having concave sides facing each other, pivot means connected with said upper end portions for swingably interconnecting said jaws to facilitate movement thereof to open and closed positions, means suspending said jaws from such a support, and counter-weighting means constructed and arranged for controlling said jaws and including a loadengaging weight vertically movable between said jaws in either position of the jaws and said counter-weighting means also including a movable connection between the Weight and the jaws and arranged to cause the weight to urge the jaw lower end portions outwardly and upwardly and maintain the same in open position, whereby when said jaws are opened and lowered on opposite sides of a load to be picked up, resting of the weight upon the load will permit the jaws to close and grasp the load to be picked up.

2. In apparatus for picking up and carrying an article, comprising a pair of opposed jaws having free lower end portions extending inwardly toward each other and having upper end portions, pivot means interconnecting said upper end portions to permit said lower end portions to shift toward and away from each other into closed and open positions, support means connected with said jaws for supporting the same, control means for causing movement of said jaws relative to each other, said control means including an article-engaging weight positioned between said jaws and vertically movable therebetween in.both of said jaw positions and also including suspending means secured to said several jaws in spaced relation with said pivot means and also secured to said weight, said suspending means being constructed and arranged to cause said suspended weight to urge said jaws outwardly from each other, whereby when said jaws are lowered on opposite sides of such an article, said weight will engage and be supported by said article and said jaws will swing toward each other to grasp such an article.

3'. A load pickup device for attachment to the end of a depending support, said device comprising a pair of opposed and curved jaws having concave sides facing each other, said jaws having free lower end portions and having upper end portions, pivot means connected with said upper end portions for swingably interconnecting said jaws to facilitate movement thereof between open and closed positions, means secured to the upper end portions of said jaws and being eonnectible with such a support for suspending the jaws therefrom, a load-engaging weight positioned between said jaws and vertically movable therebetween in both jaw positions, upwardly facing guide means secured to such a support, a pair of elongated flexible elements trained over said guide means to define opposite depending end portions, one of the end portions of each of said flexible elements being secured to said weight and the other of said end portions of each of said flexible elements being secured to a respective jaw intermediate the lower end portion thereof and said pivot means, said Weight when suspended normally maintaining said jaws in open position, whereby when said jaws are lowered on opposite sides of the load to be picked up, resting of the weight upon the load will permit the jaws to close and grasp the load therebetween.

4. Apparatus for suspension from a suitable support and for use in picking up and carrying an article, comprising a pair of opposed jaws having free lower end portions extending inwardly toward each other and having upper ends, pivot means on said jaws in widely spaced relation with said upper ends thereof and swingably interconnecting the jaws to facilitate movement thereof to open and closed positions, a pair of elongated elements each connected to a respective jaw in widely spaced relation with said pivot means and adjacent the upper end, and each of said elongated elements also being connected with such a support for supporting said jaws, an article-engaging weight vertically movable between said jaws in either position thereof, guide means secured to such a support, a pair of elongated flexible elements trained over said guide means and having opposite depending end portions, one of said depending end portions of each of said flexible elements being connected with said weight and suspending the same between the jaws and the other of said end portions of each of said flexible elements being connected to a respective jaw between said lower end portion thereof and said pivot means, whereby when said weight is lowered on such an article to be picked up and said jaws are positioned on opposite sides thereof, said article will be grasped with a force proportional to substantially the entire weight of the jaws.

5. A load pickup device for attachment to the end of a depending support, said device comprising a pair of semi-orbiculate jaws having free lower end portions and having upper end portions, said jaw upper end portions each defining an enlarged opening therein, said jaw upper end portions being disposed adjacent each other to substantially align said openings in a vertical direction, pivot means connected with said upper end portions for swingably interconnecting said jaws to facilitate movement of the jaws to open and closed positions, means for interconnecting said jaws with such a support, a loadengaging weight positioned between said jaws and being movable vertically through said vertically aligned openings and movable between the jaw lower end portions in both jaw positions, guide means secured to such a support and a pair of elongated flexible elements trained over said guide means and having opposite end portions, one of the end portions of each of said flexible elements being secured to said weight for suspending the same and the other of said end portions of each of said flexible elements being secured to a respective jaw intermediate the lower end portion thereof and said pivot means, whereby when said jaws are positioned on opposite sides of a load to be picked up and said weight is rested upon such a load, the jaws are free to close on the load.

6. A load pickup device for attachment to the end of a depending support, said device comprising a pair of opposed and curved jaws having free lower end portions and having upper end portions, said jaws having concave sides facing each other, said upper end portions each defining an enlarged opening therein, and said upper end portions being disposed adjacent each other to position the openings thereof in substantially vertical alignment, pivot means interconnecting said jaw upper end portions to maintain said openings in substantial vertical alignment and to facilitate swinging of the jaws to open and closed positions, a pair of elongated elements each connected to a respective jaw upper end portion in spaced relation above said pivot means and each being connected to such a support, a load-engaging weight positioned between said jaws and being vertically shiftable through said opening and shiftable between the jaw lower end portions in both jaw positions, a pair of sheaves spaced from each other and each being disposed above a respective jaw, means interconnecting said sheaves and being connected to such a support, a pair of elongated flexible elements each trained over a respective sheave and each having depending end portions, one of said end portions of each of said flexible elements being connected to said weight and the other of said end portions of each of said flexible elements being connected to a respective jaw intermediate said upper and lower end portions thereof, where by when said jaw and weight are lowered, and the weight is rested upon the load to be picked up, said jaws will close to grasp the load.

7. The structure recited in claim 3 wherein said elongated flexible elements are adjustable in length to permit vertical adjustment of said weight and thereby adapting said pickup device for grasping loads of various heighths.

References Cited in the file of this patent UNITED STATES PATENTS

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