US2712048A

US2712048A - Wire wound resistance and method for making same

Info

Publication number: US2712048A
Application number: US356786A
Authority: US
Inventors: Huetten Clarence; Howard R Reeve
Original assignee: Individual
Current assignee: Individual
Priority date: 1953-05-22
Filing date: 1953-05-22
Publication date: 1955-06-28
Anticipated expiration: 1972-06-28

Description

INVENTORS C. HUETTEN ET AL Filed May 22, 1953 A FIGZ Q \\\\\\\\\\\Y II'IIIIIIIIIIIIIIIIA ISISLQISLSXS CLARENCE HUETTEN BY HOWARD R. REEVE June 28, I955 WIRE WOUND RESISTANCE AND METHOD FOR MAKING SAME United States Patent 2,712,648 "ti IRE WJUND RESISTANQE AND METHOD FOR MAKING SAME Clarence ll-hictten and Howard R. Reeve, Indianapolis,

Ind, assignors to the United States of America as represented by the Secretary of the Army Application May 22, 1953, Serial No. 356,736

6 Claims. (Cl. 20163) This invention relates to electrical resistors and more particularly to terminals for wire wound resistance devices and a method of making such devices.

The use of wire wound variable resistance devices comprising an arcuately-shaped core wound with resistance wire over which a movable contact arm travels is well known in the art. Such devices usually have metal terminals clipped to the ends of the resistance winding, thereby limiting the travel of he contacting The present invention represents an improvement in such wire wound resistance devices.

An important obiect of the present invention is to pro vide a wire wound resistance device having movable con tacts touching one of its faces, said contacts being free to travel over the entire face of said device.

Another important object is to provide a wire wound resistance device which utilizes terminal inserts in its core, thereby maintaining one of its winding faces entirely free for contactors.

A further object is to provide a wire wound resistance device that is free from abrupt surface changes along the entire length of a face of the winding.

A still further object is to provide a wire wound resistance device having terminal inserts that prevent mechanical damage to the resistance wire when stresses are applied to said inserts.

Other objects and advantages of this invention will become apparent during the course of the following discussion.

In the accompanying drawing:

Fig. l is a plan View of the invention pa tially assembled;

Fig. 2 is an expanded, cross-sectional view of Fig. 1, taken at line 22 before the elements have been fused; and

Pig. 3 shows the structure of Fig. 2 after the elements have been fused.

Fig. 1 shows a core 1, which may be made of any conventional dielectric material. ireferably, as shown in Figs. 2 and 3, the core It comprises a dielectric with fabric imbedded therein. in Pig. 1 is shown the fabric grain 19 and the core is shown as being cut on a 45 bias with this grain. By cutting the core on a 45 bias to the grain 19 of the fabric, it is possible to bend the core around a small radius.

Fig. 1 further shows a keyhole-shaped slot 17 disposed on the left side of the core 1. A similar slot is disposed on the right side of core 1, but is hidden by a disc 9. A spade-shaped insert 11, made up of a shank portion 15 and a blade portion 13, has the same configuration as slot 17 and is inserted in the slot on the right side of core 1. A similar insert, not shown, is inserted in slot 17. A resistance wire is wound about the core 1 along substantially the entire length of said core, as indicated by dashed lines 2i. The disc 9 is positioned directly over the blade portion 13 of insert 11.

Fig. 2 is an expanded cross-sectional view of Fig. 1, taken along line 22, and provides a more detailed view of the present invention. T he insert ll. has a silver solder overlay '7 on its blade portion 13, and is inserted in the slot of core 1. When resistance wire 3 is wound about the core, it also incloses blade portion 13. The metallic disc 9, having a silver solder overlay 5 on one face thereof, is then placed on wire 3, so that overlay 5 is in contact with wire 3 and is in juxtaposition with overlay By applying two electrodes of a resistance soldering unit sistance wire wound on the co at points marked A and B, the solder overlays 5 and '7 are fused together.

As shown in Fig. 3, when the overlays 5 and 7 are fused together, a solder joint 23 is formed so that a portion of winding 3 is now completely contained and permanently connected between blade portion 13 of insert 11 and disc 9". Thus, a. wire wound resistance device is made that presits a face permitting an extended range of travel for contacts touching it. Also, the device is mechanically strong, preventing the wire from being broken due to stresses on the insert.

While there has been described what is, at present, con- .ered to be the preferred embodiment of this invention, will be obvious that various chan es and modifications be made therein without departing from the inventive conce,.r herein discloset.

i /hat is claimed is:

l. electrical resistance device comprising a dielece. a metal ic insert disposed wit in and interlocked with s-aio core, resistance wire wound about said core and cnclosin said insert and means comprising a metallic disc l'iaving a solder overlay on one side thereof for bonding said wire between said disc and insert.

2. A resistance device as set forth in claim 1, wherein said core has therein an irregularly-shaped slot disposed at one end thereof, said slot having a first portion narrower than a second portion, said first portion being at the edge of said core, said insert being disposed within said slot.

3. A resistance device as set forth in claim 2, wherein said insert and slo have the same configurations.

4. An electrical resistance device comprising, a relatively thin dielectric core havin at least one keyholeshaped slot at one end thereof, said slot being positioned at substantially the center of the Width of said core, a spade-shaped metallic terminal insert having a silver solder overlay on its blade, said blade and a part of the shank of said keyhole-shaped insert bein disposed within said slot, the shape of the portion of said insert within said slot being the same as the shape of said slot, said insert and said core being interlocked, a resistance wire tightly Wound about said core from one end thereof to the other end and enclosing the blade of said insert, a metallic disc having a silver solder overlay on one side thereof which is fused to the overlay of said insert for completely containing and permanently connecting a portion of said wire between said insert and said disc.

5. An electrical resistance device as set forth in claim 4, wherein said core comprises a dielectric having a fabric imbedded therei said core being cut on a 45 bias to the a grain of said fabric, whereby said core may be bent about small radii.

6. A process for producing an electrical resisetance device including dielectric core, netallic terminals, and recomprising the steps of, interlocking a ke hole-shaped metallic terminal insert having a silver solder overlay on its blade portion with a relatively thin, rectangularly-shaped dielectric core having at least one spade-shaped slot at one end thereof to receive said insert, said slot being substantially at the center of the width of said core and complementing the portier. of said insert tliercwithin, tightly u'iding resistance wire about. said core from one end thereof to the other and enclosing said insert, and fusing a metallic disc having a silver solder overlay on one side thereof to the overlay of said insert to completely contain and permanently connect a portion of said wire between said insert and said disc.

1 Nov. 3, 1914 rlo z June 20, 1939

Claims

1. AN ELECTRICAL RESISTANCE DEVICE COMPRISING A DIELECTRIC CORE, A METALLIC INSERT DISPOSED WITHIN AND INTERLOCKED WITH SAID CORE, RESISTANCE WIRE WOUND ABOUT SAID CORE AND ENCLOSING SAID INERT AND MEANS COMPRISING A METALLIC DISC HAVING A SOLDER OVERLAY ON ONE SIDE THEREOF FOR BONDING SAID WIRE BETWEEN SAID DISC AND SAID INSERT.