US942156A - Grid resistance. - Google Patents

Description

H. J. WIEGAND.

GRID RESISTANCE. APPLICATION FILED MAR. 29, 1909.

Patented Dec. 7, 1909.

orrior.

HENRY .T. WIEGAND, or MILWAUKEE, wxsconsm, Assronon To THE CUTLER;

HAMMER MFG. (30., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

GRID RESISTANCE.

Stateof lVisconsin, have invented new and useful improvements in Grid Resistances, of

which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of this specifi ation.

My invention relates to improvements in grid resistances.

As usually constructed, grid resistances- -cons1st of a long, retiexed bar, havmg a number of convolutions, and are more or less flimsy. To give such resistance grids the requisite strength, it is desirable to utilize a metal reinforcing member, substantially U-shaped in cross section, which isv placed over the ends of the convolutions. The metal reinforcing members are, of course, insulated from the grid. Owing to the fact that the grids often become er; tremely hot during service and expand, the reinforcing memba's are loosened and have a tendency to drop olf. lVith the usual forms of grid it is a difficult matter to securely fasten reinforcing strips thereto.

The object of my inventionis to provide a grid having portions designed to be engaged by portions of the reinforcing members so that said members will be held thereon under all conditions of service.

In order that my invention may be thoroughly understood I have illustrated the preferred form thereof in the accompanying drawings. v

In the accon'ipanying drawings,l igure l is an elevation of a grid resistance embodying my invention; Fig. 2 is an end view of a portion of the grid showing the means of securing a reinforcing member in position, and Fig. 3 is an enlarged perspective view of one corner of the grid,-showing the reinforcing member with one corner bent into position.

In the embodiment of my invention, as shown in the drawing, I provide a grid resistance A, consisting of a rctlexed strip or bar having a number of convolutions a. The outer bars a are preferably of the same length as the intermediate bars and are provided with suitable terminals o by means of which the grid may be fastened in po- Specification of Letters Patent.

Application filed March 29, 1909.

Patented Dec. 7, 1909.

Serial No. 486,513.

sition and electrically connected in circuit. The outer bars are provided at or near their ends with lugs a Said lugs a are preferably provided with an inclined face a, for a purpose hereinafter set forth.

Over the edges of the grid, on opposite sides, or, in other words, over the ends of the bars or convolntions, I place reinforcing strips B, preferably substantially U-shaped in cross section. Each of the reinforcing strips is preferably provided with one or more ribs or beads b, which are stamped up therefrom to strengthen it transversely. Between each of the reinforcing strips and the grid, I interpose an insulating strip C, made of any suitable material, to insulate the reinforcing strips from the grid; It is preferable to bend the sides of the reinforcing strips invardly so as to tightly grip the grid. i

In order to prevent the reinforcing strips from becoming loose and dropping off, due to the expansion of the grid when heated, the corners of the reinforcing and insulating strips are bent inwardly, as at Z)", so as to engage the surface a of the lugs a The reinforcing strips are thus firmly held in place and can only be removed after the corners '7) have been bent outwardly out of engagement with the lugs. 1

By providing the lugs with an inclined face (2*, as shown in the drawing, it is much easier to bend the corners of the reinforcing member thereover than if the lugs were of other form. However, I desire it to be understood that the lugs may assume any desired form.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In combination, a grid resistance having lugs thereon, and a reinforcing strip placed over the edge of said grid and having portions bent around said lugs to retain the same'on said grid.

2. In combination, a grid resistance having lugs formed on the end bars thereof, substantially U-shaped reinfoming strips placed over the edges of the grid, said reinforcing strips having portions thereof bent around said lugs.

3. In combination, a grid resistance having lugs formed on the end bars thereof,

l said lugs having an inclined. face, reinforcing strips placed over the edges of said grid ing and insulatin stri s havin and having portions bent over the inclined thereof bent aroun d said lugs. portlons faces of said lugs, and means for insulating In Witness whereof, I have hereuntosubthe reinforcing strips from the grid. scribed my name in the presence of tw i 5 4:. In combination, a grid resistance havnesses.

ing lugs formed on the end bars thereof,

substantially U -shaped reinforcing strips HENRY G placed over the edges of said grid, and in- Witnesses: sulating strips interposed between said rein- S. W. F ITZ GERALD,

10 forcing strips and said grid, said reinforc- F. H. HUBBARD.

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