US918547A - Resistance unit. - Google Patents

Description

H. E. HEATH. RESISTANCE UNIT. APPLICATION rum) MAY 7 1907.

Patented Apr. 20, 1909.

Inventor Harry )3; Heath,

UNITED STATES BATENT; OFFICE.

HARRY E. HEATH, or LYNN, MASSACHUSETTS, Assrenon 'ro' GENERALELEGTRIO COMPANY, A CORPORATION OF NEW YORK.

' RESISTANCE UNIT.-

Specification of Letters Patent.

Patented April 20, 1909.

Application filed May 7, 1907. sum No. 372,325.

citizen of the United States, residing at Lynn, county of Essex, State of Massachu setts, have invented certain newand useful Improvements in Resistance. Units, of which the following is a specification.

This'invention relatesto resistance units for electric circuits and has for its obict the provision of a device of thischaracter which is simple and cheap to construct and combines lightness and strength with a high degree of efficiency and durability.

One of the objects of my invention is to provide a resistance unit which shall have as large a surface and as small an amountof material as possible.

in carrying out my invention 1 make the resistance unit in the form of a tube formed of strips of material wound into a close spiral. This may be done in various ways, two forms being shown and described in the accom panying specification.

in the drawings in which'I have illustrated my invention, Figure l is an elevation partly in section of one formof my invention; and Fig. 2 is a similar view of another form without the connecting terminals.

in the construction of my resistance unit 1 take a strip of resistance conducting ma.- terial, such as sheet iron or the like, and wind it into a spiral with insulating material between the (Wm-lapping turns. "he insulating; material is preferably of flexible and refractory material, such as asbestos. in the form shown in Fig. 1, the asbestos and the metal are inv strips of substantially equal width. The metal is lirst bent tothe l'orm shown in the drawing: in any desired manner, as for instance by passing it through a die. The insulating material here described being flexible will conform to the shape of' the metallic strip without any previous treatment.- lhc two strips are arranged so as to overlap each other and are then wound into a closed spiral so that the metal turns will overlap each other \\ith the asbestos strip ll between them. The strips may be olany dcsircd width so that the strip may overlap itself any number of times, and in this way the sti ips form a corrugated llcxible tube, in which the turns are locked together by the bends in the strips. The tube is then pro vided with cminccting terminals 12 and 13,

manner.

and a rod 14 isypassed through the tube and terminals provided with nuts 15 for securing I the whole in place. The tube may then be mounted between the brackets 16, if desired. In the form shown in Fig. 2, the flat'resistance conducting strip 17 and the lisbestos strip 18 are wound in the form of a closed spiral as shown. In this form the corrugations are applied after the tube is formed. These corrugations'm'ay be circumferential and may thus be applied in a very simple The corrugations in this case, as well as in the form shown in'Fig. 1 not only lock the spiral turns together but also lend strength to the tubes as a Whole. 7

It will be understood, of course, thatvarious modifications, both as to the material and the method of construction, may be resorted to without departing from the spirit of my invention, the scope of which is set forth in the annexed claims. What I claim as new and desire to secure by Letters Patent of the United States, ,is,

1. 'A resistance tube comprising similarly shaped strips 'ofasbestos and conducting ma-' terial spirally wound so as. to overlap each other. i

2. -A resistance tube comprisinga resistance conductingstrip wound into a closed spiral having a strip of asbestos of substantiallythe samelwidt'h between the overlapping turns.

3. A resistance tube comprising overlapping stripsof insulating'and conducting material wound into a closed spiral, the adja' cent edges of said spiral being interlocked 4. A resistance tube comprisingoverlapping strips of insulating and conducting ma-' terial wound into a closed spiral, the adjacent edges of said spiral being locked together by cm'rugati'ons.

5. A flexible resistance tube comprising a resistance conducting strip wound into a closed spiral, and a strip of asbestos wound between the overlapping turns, the said tube beimg provided with corrugations for locking; 100

the turns together. 7 In' witness whereof, I have hereunto set my hand this third dayof Way,19 07.

\ HARRY E. H'EA'IH. Witnesses: I

Join: A. MoMA'NUs, Jr., PHILIP F. HARRINGTON.

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