US3926420A - Sheet metal securing device - Google Patents

Abstract

A clamp for securing sheet metal pieces for splicing comprises a shaft having a handle and a threaded end spaced from the handle for engaging a bore in a metal sheet, and a structural spacing device mounted on the shaft. A lower member of the spacing device abuts the sheet metal. When the clamp is in place, a spring mounted on the shaft draws the sheet metal up toward the lower member of the spacing device, thus holding the joint in place, and preventing warping or buckling of the sheet metal from the heat.

Description

United States Patent 1191 Raymond Dec. 16, 1975 1 SHEET METAL SECURING DEVICE [76] Inventor: Edwin S. Raymond, 1001 N. Main,

Las Vegas, Nev. 89101 [22] Filed: July 8, 1974 21 App]. No.: 486,504

[52] US. Cl. 269/47; 269/254 CS [51] Int. Cl. B25B 5/00 [58] Field of Search 269/2, 47, 49, 91, 93, 269/254 CS [56] References Cited UNITED STATES PATENTS 2,339,529 l/l944 Unetic 269/47 2,576,003 11/1951 Dry 269/254 CS 3,588,082 6/1971 Chiffoleau 26 9/49 FOREIGN PATENTS OR APPLICATIONS France 269/49 Primary Examiner-Roy Lake Assistant ExaminerMark S. Bicks Attorney, Agent, or Firm-Edward J. Quirk [57] ABSTRACT A clamp for securing sheet metal pieces for splicing comprises a shaft having a handle and a threaded end spaced from the handle for engaging a bore in a metal sheet, and a structural spacing device mounted on the shaft. A lower member of the spacing device abuts the sheet metal. When the clamp is in place, a spring mounted on the shaft draws the sheet metal up toward the lower member of the spacing device, thus holding the joint in place, and preventing warping or buckling of the sheet metal from the heat.

4 Claims, 2 Drawing Figures US. Patent Dec. 16, 1975 3,926,420

FIGURE I.

FIGURE 2.

SHEET METAL SECURING DEVICE BACKGROUND OF THE INVENTION Sheet metal workers frequently find a necessity to join two panels of sheet metal by welding, brazing, or the like. This particularly true for automobile body work, where a damaged panel is cut away and replaced with a new panel which is first cut to fit properly and then spliced to existing panels. Since joining the two panels in entirely flush manner is not possible, unless flanges are provided on the sheet metal, it is common practice to overlap the edges of one panel over the other, often by l2 inches.

In some cases, the seam of the upper and lower panels can be held by a clamp, such as a C-clamp or elon gated vise-grip clamp, while the seam is welded. In many cases, however, and especially in automobile body work, the infrastructure behind the sheet metal (e. g., wheel housing, or floor continuation) restricts the use of conventional clamping devices. In this case, it is common for the sheet metal worker to improvise, pressing the upper metal piece against overlapped panel with, e.g., the end of a long screwdriver. He then presses on the handle of the screwdriver with his shoulder, freeing both hands to make the weld. In some cases, it may be necessary to use two men to hold the sheet metal piece in place for welding.

Such methods have obvious drawbacks. In additional to being somewhat haphazard, quality control suffers because when heat is applied for welding and brazing, the bottom panel tends to pull away, and the seam tends to buckle and warp. As a result, to obtain a smooth finish, it is necessary to use very large amounts of plastic filling material to conceal the seam. This warping effect frequently occurs well away from the seam, necessitating the use of much more filling plastic than should be necessary. Once the plastic is in place, it must be sanded to a smooth finish, which can be quite time-consuming.

While other tools are known to hold panels in place, they generally are quite complex, often requiring an electrical source, and are therefore not used. An exam ple of such a tool is described in Erwin et al., US. Pat. No. 2,379,136; this device operates with an electromagnet.

Accordingly, it is an object of this invention to provide an inexpensive and simple yet flexible tool to secure sheet metal panels for welding or brazing.

SUMMARY OF THE INVENTION A device for securing sheet metal pieces comprises an elongated shaft having a handle and a threaded end, spaced from the handle, for engaging sheet metal, a structural spacing device removably mounted on the shaft between the handle and the threaded end, and spring means for urging the threaded end toward the spacing device when the threaded end engages the sheet metal.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an exploded view of the clamp of the invention, positioned to weld a curved seam.

FIG. 2 shows the clamp in placc for fastening two pieces of sheet metal.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1, the clamp comprises shaft 2 with a handle 4 secured at one end thereof. The shaft has a threaded end 6 for engaging a bore in the sheet metal. The shaft extends through helical spring 8, and through sleeve 10 in brace 12, which is fabricated from heattreated carbon steel. Brace 12, which is essentially a structural spacer for carrying the handle and spring, comprises a substantially flat member 14 and arcuate member 16, having co-terminating ends. Sleeve 10 extends from a hole in the middle of member 14 (not shown) to hole 18 at the top of arcuate member 16. While the sleeve is not essential to the invention, it helps to keep the brace members 14 and 16 from bending toward each other when the securing device is in use.

FIG. 2 shows the clamp in operation in securing sheet metal pieces 20 and 22, with metal piece 22 overlapping piece 20 at the seam. In preparing the metal pieces for welding or brazing, holes 24 are drilled in the bottom sheet 20 at spaced intervals of e.g. l2 inches along the seam, and in close proximity to the seam. The drilled holes are preferably located as close as possible to the seam without being covered by the overlapping sheet metal in order to make the seam accessible to the welding tool at a position close to the hole.

After the holes are drilled, the clamp is set in place as shown by turning the handle and engaging the threaded end 6 of shaft 2 into bore 24. As the threaded end turns into the bore, spring 8 compresses, drawing the bottom piece of sheet metal up toward the base member 14 of the brace, which extends perpendicularly to the direction of the seam, holding the two pieces of sheet metal in place. Welding or brazing is effected along the seam on either side of sleeve 10; notches 26 and 28 in base member 14 are provided to permit the placement of welds, such as weld 30, in close proximity to the hole. As the sheet metal becomes hot from heat provided by the fastening tool, the metal becomes more workable and subject to thermal stresses. However, rather than warping or buckling as would normally be the case, the metal is drawn upwardly toward the brace by the compression of the spring, which urges the threaded end of shaft 2 toward the brace. Therefore, instead of buckling, a relatively uniform, smooth seam can be obtained.

In welding along a seam, the first welds may be placed on an end of the seam, such as welds 32 and 34 in FIG. 2, or may be placed in the middle position illustrated by the placement of the clamp in FIG. 2. For long seams, it is preferable to use a plurality of clamps placed at various locations along the seam prior to making the first weld; in this manner, the two metal pieces can be adjusted to the precise desired alignment prior to welding.

In some circumstances, it may be inconvenient or im possible to position the brace perpendicularly to the seam; for example, if the seam is adjacent to an automobile window, or to a piece having extreme curvature. In this case, the clamp may be aligned parallel to the seam (i.e., rotated around the shaft from the position shown in FIG. 2), and welding can take place through holes 36 and 38. Holes 36 and 38 are located in member 14, adjacent to and on either side of sleeve 10. Operation of the clamp is especially convenient since it can be removed and inserted at another loca 3 tion with one hand, while the other hand is holding an acetylene torch.

The brace piece 12 of the clamp is reversible on the shaft to allow work on concave metal surfaces. If a seam is desired in two metal pieces forming a concave curve, the clamp is assembled as shown in the alignment of FIG. 1, and the clamp is then used in the same manner as shown in FIG. 2. Corresponding notches 40 and 42 and holes 44 and 46 exist in arcuate member 16 of brace 12 for welding in close proximity to sleeve 10.

While the brace has been described as having a substantially flat member and an arcuate member, for automobile work, it is actually preferable to have member 14 slightly bowed inwardly, since most automobile surfaces are slightly convex. While a helical spring has been shown for biasing the shaft outwardly from the splice, any biasing means may be used; for example, member 14 may be bowed slightly inwardly from its ends and may thereby exert outward force at its center when the shaft is secured to the sheet metal.

Filling and finishing the surface after splicing is much simpler when the clamp of the invention is used, since a comparatively uniform seam is obtained. Substantially less plastic filler, and correspondingly less sanding, is required, resulting in a saving of both time and materials. In addition, use of the clamp enables small sections on automobile body, which are badly dented, torn, or rusted away, to be replaced without replacing very large panels, such as quarterpanels. The clamp of the invention is particularly useful in combination with the flanging device claimed in my US. Pat. No. 3,808,869, issued May 7, 1974, which is used to selectively bend sheet metal prior to joining.

It is understood that several modifications easily understood to those skilled in the art may be made to the clamp described herein and still come within the spirit and scope of the invention.

I claim:

1. A clamp for securing sheet metal comprising:

a shaft having handle means for manually rotating the shaft at one end thereof and thread means for engaging a bore in the sheet metal at the other end thereof,

brace means adapted to receive the shaft comprising a substantially flat member and an arcuate member structurally spaced from each other, each member having axially aligned holes therein to permit said shaft to pass therethrough, and

biasing means associated with said shaft for urging the sheet metal toward the brace means when the threaded end of the shaft engages the sheet metal.

2. The clamp of claim 1 wherein at least one member of the brace means contains a plurality of openings therein in close proximity to the location of the threaded end of the shaft when the shaft engages a bore in the sheet metal, thereby permitting welding at a location near said bore.

3. The clamp of claim 1 also comprising a sleeve structurally fixed between the two axial holes for re ceiving said shaft.

4. The clamp of claim 1 wherein the brace means is reversible on the shaft, enabling either the substantially flat member or the arcuate member to abut the sheet metal when the clamp is in operating position.

Claims (4)

1. A clamp for securing sheet metal comprising: a shaft having handle means for manually rotating the shaft at one end thereof and thread means for engaging a bore in the sheet metal at the other end thereof, brace means adapted to receive the shaft comprising a substantially flat member and an arcuate member structurally spaced from each other, each member having axially aligned holes therein to permit said shaft to pass therethrough, and biasing means associated with said shaft for urging the sheet metal toward the brace means when the threaded end of the shaft engages the sheet metal.

2. The clamp of claim 1 wherein at least one member of the brace means contains a plurality of openings therein in close proximity to the location of the threaded end of the shaft when the shaft engages a bore in the sheet metal, thereby permitting welding at a location near said bore.

3. The clamp of claim 1 also comprising a sleeve structurally fixed between the two axial holes for receiving said shaft.

4. The clamp of claim 1 wherein the brace means is reversible on the shaft, enabling either the substantially flat member or the arcuate member to abut the sheet metal when the clamp is in operating position.

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