US2972270A - Sheet metal bending tool - Google Patents

Description

Feb. 21, 1961 s w KROLICK 2,972,270

SHEET METAL BENDING TOOL Filed Jan. 26, 1959 INVENTOR. STANLEY W/I ROLICK Y iZAMQ j SHEET METAL BENDING TOOL Stanley W. Krolick, 995 W. 5th St., Livermore, Calif.

Filed Jan. 26, 1959, Ser. No. 789,041

2 Claims. (Cl. 81-15) This invention generally relates to hand operated tools for bending sheet metal or the like, and is more particularly directed towards such a tool for producing so-called government or pocket locks on sheet metal duct work.

In the fabrication of sheet metal ducts, the workman is required to provide interconnected flanges at numerous locations, such as at points of juncture, and in this connection, government or pocket locks are frequently specified. As is well known to those in the art, these locks are usually formed by manually beating with a hammer one of a pair of flanges to form an angle of about 45 degrees relative to the other flange, and then utilizing a hand grip tool to forcibly bring the two flanges into immediate adjacent relationship. The hand grip tools presently available are not satisfactory from a number of viewpoints, requiring excessive effort on the part of the operator. Also, in many instances, such as in the case of overhead duct work, such tools cannot be properly utilized at all.

It is therefore an object of the present invention to provide a sheet metal bending tool which is arranged to give maximum mechanical advantage to the user and in which the jaws are mounted in a novel manner to expedite the use of the tool.

Another object of this invention is to provide a tool utilizing a pair of jaw elements selectively movable from and towards each other and in which the jaws are arranged for movement about pivots which result in the normally planar opposed surfaces of the jaws, being disposed in parallel adjacent relationship when the jaws are closed and in angular related relationship when the jaws are open.

A further object of the invention is to provide a tool as hereinabove described in which the jaw elements are mounted on a pair of cooperating manually engageable handles extending for a substantial distance, and in which each of the jaws consists of a planar element whose longitudinal axis is offset from the normal transverse axis of the tool.

Yet another object of the invention is to provide a tool of the character described in which the jaws open and shut relative to stationary corner portions thereof so as to facilitate their use and permit ready engagement of the flanges being engaged thereby.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming part of the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as set forth in the claims.

Referring to said drawing:

Figure 1 is a side elevational view of the tool of the present invention.

Figure 2 is a top plan view thereof.

Figure 3 is an enlarged portional view similar to Figure 1 and illustrating the position of the parts when the jaws are in their open position.

Staes Pa e 2,972,270 .gPatented Feb. 21,, 1961 Figure 4 is an end elevational view of the jaws in their open position.

Figure 5 is a transverse cross sectional viewtaken substantially in the plane indicated by line 5-5 of Figure 1.

Figure 6 is a portional perspective view of a government or pocket lock during course of formation thereof.

As here illustrated, the tool of the present invention incorporates a pair of jaw elements indicated at 6 and 7 respectively which are adapted to be selectively opened and closed by means of a pair of pivotally connected handle elements 8 and 9. As is typical with most hand operated clamping tools, when the handles are spread apart as illustrated in Figures 3 and 4 of the drawing, the jaws will likewise be disposed in their open position. Conversely, by bringing the handles together as shown in Figure 1 of the drawing, the jaw elements 6 and '7 will be brought into immediate adjacent relationship and thereby in a condition to form the government lock on a pair of sheetmetal flanges or otherwise apply pressure therebetween. In order to translate handle movement into corresponding movement of the jawswith a maximum mechanical advantage resulting therefrom, the structure dis closed in the drawing and presently to be described is preferably employed. As here illustrated, each of the handles comprises an axially extending element 12 and 13 which may be of cylindrical or other desired cross sectional configuration. The inner end of each of the elements is flattened and deformed to define an acute angle with the axis of the element so as to provide a pair of extensions 14 and 16 respectively. The extensions 14 and 16 are integral with their respective handle elements, and the distal ends thereof are pivotally secured together such as by a pin 17 or the like, such pivotal mounting permitting free movement of the handle elements 12 and 13 from and towards each other.

Pivotally secured to the handles are a pair of arcuate flat links 21 and 22, the links having ends thereof secured to the respective extensions by pivot pins 23 and 24. It will be noted that the link 21, for example, has a first portion 26 of arcuate configuration with the radius of curvature being generated approximately from the other link pivot point 24 and terminating ina reverse curve portion 27. The other link 22' is of similar configuration with its first arcuate portion 28 being curved about the pivot pin 23 and similarly provided with a reverse curved portion 29. The links are likewise pivotally interconnected by a pin 30 medially of their ends. The free ends of the links have secured thereto in a manner presently to be explained the jaw elements 6 and 7. However, irrespective of the shape or positioning of the jaws on the links, it will be readily understood that as the handles are brought into adjacent relationship from the position illustrated in Figure 3, the links 21 and 22 will be moved until the ends of the curved portions 27 and 29 will be brought towards each other and consequently effect a closing of the jaws. On the other hand, the jaws are opened through a contrary movement of the handle elements.

The shape and positioning of the jaws 6 and 7 on the respective links constitutes an important feature of the present invention. It will be seen that the jaws are each formed of a relatively planar block of material with the opposed confronting faces 31 and 32 being knurled, if desired, to provide a greater gripping action when the jaws are engaged with the sheet metal or other object being clamped. It will also be noted from observing Figure 2 of the drawing that the longitudinal axis of each jaw defines an angle of about 24 degrees with the axes of the pivots 17, 23, 24 and 30, or with what might be termed a normal transverse axis of the tool relative to the axes of the handle elements. It is also important to note that when the jaws are in their closed position as shown in Figures 1 and 2, the jaws are disposed in parallel adjacent relationship relative to each other so as to permit the necessary clamping action therebetween. However, when the jaws are oepned as shown in Figures 3 and 4, one corner of each of the jaws, due to their positioning on the links and the nature of link movement will remain in immediately adjacent relationship as indicated at 36 with the jaws having their widest opening on the diagonally opposite corners 37 and 38 of the respective jaws. Thus, when the handles are brought together, there is little or no movement of the jaw portions adjacent the corner 36 and the other portions of the jaws are then brought together with the corners 37 and 38 having maximum movement towards each other. In this manner, the jaws in their open position may be easily placed on the flanges to be secured or bent together and then by squeezing the handles 8 and 9, may be gradually brought together to provide the necessary deformation to the sheet metal. Also, by virtue of the angular disposition of the jaws relative to a longitudinal or transverse axis of the tool, the entire unit may be used in otherwise inaccessible locations, but without in any way sacrificing any of the mechanical advantage arising from the link and extension arrangement.

A type of operation for which the tool has particular utility is in the formation of a government or pocket lock on sheet metal duct work. As shown in Figure 6, such a lock is formed at the juncture between a pair of ducts 51 and 52. The end of the former is bent back on itself as shown at 53, then extends outwardly in an angularly disposed web 54 and terminates in a flange 56 parallel and spaced to portion 53. Duct 52 has an end angular flange 57 disposed adjacent web 54 between flange 56 and portion 53. By bending flange 56 over flange 57, the lock is provided.

What is claimed is:

1. A sheet metal bending tool comprising a pair of handles, means pivotally securing said handles together adjacent the ends thereof, a pair of links with one of such links being pivotally attached to one of said handles and the other of said links being pivotally attached to the other of said handles, means pivotally securing said links together, each of said linkshaving a jaw element operatively secured thereto, each of said jaw elements comprising a generally rectangular block having a longitudinal axis offset from a transverse axis of said tool and likewise defining an angle with the longitudinal axis of the tool, said jaws having abutting corner portions normally positioned immediately adjacent each other during opening and closing of said handles, and said jaws having corner portions at diagonally opposed positions relative to said adjacent portions having a maximum amount of movement from and towards each other upon actuation of the handles.

2. Apparatus as set forth in claim 1 in which the opposed confronting surfaces of said jaws are substantially planar and positioned in immediately adjacent relationship upon closing of said handles.

References Cited in the file of this patent UNITED STATES PATENTS 791,245 Casterlin May 30, 1905 869,211 Mills Oct. 22, 1907 1,093,400 Gottfrid Apr. 14, 1914 1,987,127 Rice Jan. 8, 1935 2,507,784 Hamel May 16, 1950 FOREIGN PATENTS 926,929 Germany Apr. 25, 1955

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