US1862014A - Method of making thermosensitive resistors - Google Patents

Description

June 7, 1932. o, GRONDAHL 1,862,014

METHOD OF MAKING THERMOSENSITIVE RESISTORS Original Filed July 8, 1923 INVENTOR. 1,.0. Grondahl,

Patented June 7, 1932 UNITED STATES PATENT OFFICE LABS O. GRONDAHL, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH & SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METHOD OF MAKING THERMOSENSITIVE RESISTORS Original application filed January 8, 1923, Serial No. 611,286. Yatent No. 1,741,231, dated December 31, 1929. Divided and this application filed April 25, 1929. Serial No. 357,993.

My invention relates to electrical translating apparatus of the thermosensitive type, and has for an object the provision of novel and improved methods for manufacturing devices of this type.

The present application is a division of my copending application, Serial No. 611,286, filed January 8, 1923, for electrical translating apparatus now Patent No. 1,741,231, De-

cember 31, 1929.

ll will describe several methods embodying my invention, and will then point out the novel features thereof in claims.

In the accompanying drawing, Fig. 1 is a view showing one form of thermos-ensltive device which may be manufactured in accordance with methods embodying my invention. Fig. 2 is a View showing a modification of the device shown in Fig. 1 and also capable of being manufactured by methods embodying my invention.

Similar reference characters refer to similar parts in both of the views.

Referring first to Fig. 1, the device, which '25 is designated as a whole by the reference character R comprises a glass bulb '4', one end of which is provided with a plugS having contacts or terminals 9 and 12, and the other end of which is provided with a similar plug 8 having contacts or terminals 9 and 12.

Located within the bulb 7 are a heating element H and two electrodes 10 and 11, all of which are in the form of wires. The electrodes may, for examples, be of copper, or of nickel plated with copper. These electrodes are first twisted together or intertwined to form two helical conductors with the turns of one alternating with the turns of the other, and the heating element H is then twisted around the electrodes. The whole unit is then heated in a furnace to transform the copper surface of each electrode into copper oxide which is a thermosensitive substance, so that each turn of each electrode is separated from the adjacent turns of the other electrode and from the heating element by a coating of this substance. Or to express the same thing in a different way the intertwined electrodes are embedded in the thermosensitive substance. The device shown in Fig. 1 may be so designed as to carry relatively heavy currents.

The two terminals of the heating element H are connected with the two contacts 9 and 12, respectively, of the terminal plug 8. The two electrodes 10 and 11 are connected with the two terminals 9 and 12 respectively, of the plug 8.

Referring now to Fig. 2, the device, which is here designated as a whole by the reference character R comprises a glass bulb 7 provided with two plugs 8 and8, as in the preceding view. ln Fig. 2, however, the electrodes, which are here designated 10 and 11", are in the form of wires or strips, which are placed side by side, and the heating element H is then wrapped around these electrodes. The electrodes may be of copper, or they may be of other suitable metal such as nickel, plated with copper. In either case, after the electrodes and the'heating element are assembled, the unit is baked in a furnace to convert the copper surfaces of the electrodes into copper oxide, so that these electrodes are separated from each other and from the heating element H by a thermosensitive substance. After the baking is finished, the parts are mounted'in the tube 7 gr d cionnected with the plug contacts as in Although T have herein described only a few methods embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

- Havingthus described my invention, what I claim is:

1. The method of constructing a thermosensitive device, which consists in copper plating two metallic electrodes, twisting them together, and then heating them to form a layer of thermosensitive substance between the electrodes.

2. The method of constructing a thermosensitive device, which consists in twisting two copper wires together so that the turns of one wire alternate with the turns of the other, and then heating them to form a layer of copper oxide'between the wires.

3. The method of constructing a thermosensitive device, which consists in copper plating two metallic electrodes, twisting them together so that the turns of one alternate with the turns of the other, and then heating them to form a layer of copper oxide between the wires.

4. The method of constructing a thermosensitive device, which consists in twisting two copper conductors together so that the turns of one alternate with the turns of the other, twisting a heating element around said conductors, and heatin the unit to form a layer of cop er oxide etween the two conductors and etween each conductor and the heating element.

5. The method of constructing a thermosensitive device, which consists .in copper plating two metallic electrodes, twisting them together so that the turns of one alternate with the turns of the other, twisting a heating element around said electrodes, and heating the entire unit to form a layer of copper oxide between the two electrodes and between each electrode and the heating element.

In testimony whereof I aflix my signature.

LARS O. GRONDAHL.

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