US2665358A - Resistor grid - Google Patents

Description

R. E. DU 5015 Jan. 5, 1954 RESISTOR GRID Filed Feb. 27, 1952 w WI N INVENTOR ROBERT E. Du 8015 ATTORNEY Patented Jan. 5, 1954 UNITED STATES PATENT OFFICE RESISTOR GRID Robert E. Du Bois, Hammond, Ind. Application February 27, 1952, Serial N 0. 273,686

3 Claims.

This invention relates generally to electrical resistors and more particularly to the structure of resistance grid elements.

It is quite common to assemble a plurality of zig-zag resistor grids into a compact resistor bank for various commercial adaptations, and a good example of such structure is shown in the prior art by Patent No. 2,491,193, to Herbert H. Matthews. One of the problems attendant to such structures of the prior art is the lack of inherent rigidity in the grid elements, with the subsequent warpage and occasional breakage under vibrational and other stresses applied to such grids, particularly when used on locomotives.

It is, therefore, the primary object of this invention to provide an improved resistor grid having a substantially increased inherent rigidity over similar structures of the prior art.

A more specific object of this invention is to provide a zig-zag resistor grid having a continual curvature over its entire length.

Another object of this invention is to provide a zig-zag resistor grid in which adjacent sections of the grid are oppositely curved and in which the connecting portions of the adjacent sections are of a gradually reversing curvature.

Another object of this invention is to provide a resistor grid of a zig-zag character in which adjacent portions of the grid are electrically separated without the waste of grid material during formation of the grid.

With the foregoing and other objects in view, the invention resides in the following specification and appended claims, certain embodiments and details of construction of which are shown in the accompanying drawings, in which:

Figure 1 is a plan view of the resistor grid;

Figure 2 is a sectional view in front elevation taken along the lines 22 of Figure 1; and

Figure 3 is a perspective view of a portion of the resistor grid.

Referring more particularly to the drawings, a resistance grid l of suitable resistance metal is shown having a terminal 2. Terminal 2 is perforated at 3 to receive any suitable mounting bolt, not shown. The grid is stamped from a sheet of rectangular resistance metal into the zig-zag formation shown, thereby providing a conductive path for electrical currents of considerable length from one end to the other of said grid. In stamping the grid, suitable combined cutting and forming dies are utilized to sever adjacent portions of the grid and to impart a reverse curvature to said portions.

Thus, as shown in the drawing, adjacent sections 4 and 5 are severed at their edges 6 and 1 and each are reversely curved, section 4 being concave and section 5 being convex as viewed in Figure 1. The severance at the edges 6 and 1, together with the formation into reversely curved sections, electrically separates sections 4 and 5 at their edges 1 and 6 by the distance designated in Figure 2.

The bridging section 8 of the adjacent sections 4 and 5 is formed during the stamping operation with a reverse curvature at 9. Thus convex curvature of section 5, for example, is partially extended over the length of the bridging section 8. The totally convex character of the section 8 is changed beginning at points [0 and I I, where the outer edges are gradually reversely formed to become totally concave to agree in character with section 4. In tracing the conductive path from section '5 to section 4, then as shown in Figure 3, the curvature is seen to be totally convex in the first portion of bridge 8 until the points Ill and I I are reached. The grid, then increasing, becomes concave while the convex nature thereof terminates at point l2. In other words, the two curvatures overlap and merge with one another. Thus it is seen that at no place in the grid l is there a flat section which would tend to weaken the rigidity of the grids between its terminals.

I claim:

1. A zig-zag resistor grid comprising adjacent sections and bridging sections connecting the adjacent sections, said adjacent resistor sections being of opposite curvature and being electrically separated from each other, and said bridging sections having concave and convex portions which gradually merge with each other.

resistor grid comprising adjacent bridging sections connecting the adjacent sections, the said sections being successively reversed in curvature over their transverse dimensions throughout the length of the resistor grid.

3. A zig-zag resistor sections of opposite cross sectional curvature and ROBERT DU 3018.

References Cited in the flle of this patent UNITED STATES PATENTS Name Otte FOREIGN PATENTS Country Great Britain Number Date 2,107,187

Number Date 299,500

Oct. 29, 1928 Feb. 1, 1938

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