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Publication numberUS310472 A
Publication typeGrant
Publication dateJan 6, 1885
Publication numberUS 310472 A, US 310472A, US-A-310472, US310472 A, US310472A
InventorsWilliam Stanley
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Thermal cut-out
US 310472 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

(No Model.)



No. 310,472. Patented Jan. 6,1885.




SPECIFICATION forming pari'. of Letters Patent No. 310,@72, dated January 6, 1885.

Application filed December 5, 1882. Renewed July S, 1834. (No model.)

To all whom 'it may concern..-

Beit known that I, WILLIAM STANLEY, Jr., of Englewood, in the county of Bergen and State of New Jersey, have invented certain new and useful Improvements in Electric Cut Outs; and I declare the following to be a clear and exact description of the invention, when read in connection with the accompanying drawings.

The object ci' my invention is to prevent the dangers arising from and the loss of energy incident to overloading the conductor of an electric current, and this whether by a sudden increase in the current or by lessening the resistance of the conductor, or by reason of cross-circuiting, or for any other cause; and my invention consists of an air-chamber so arranged in proximity to or surrounding` an electric conductor that the heat generated in the conductor by reason of an abnormal current shall effect a rupture of the conductor by expanding the air in the air-chamber, and thereby displacing a movable body arranged to close such chamber, and connected with or constituting a part of such conductor.

In the drawings, Figure I is a perspective view of one form of cut-out embodying my improvements. Fig. II is a detail central section of the same, and Figs. III and IV represent inodications thereof.

A is a tube, preferably, but not necessarily, of glass, which is closed at each end in any convenient way in the present case by blocks B, which also support it in proper position upon a wall, base, or bracket, C-and it is provided with a capillary passage, A, which unites the air-chamber A2 with the receivingchamber A5. Terminating in the air-chamber are two wires, D D', which constitute the conductor of an electric current. One of these wires, D, enters the air-chamber through the capillary passage, without filling it, however, and its end and the end of the wire D are so arranged that a globule of mercury, E, too large to pass through. the capillary passage by reason of its own weight serves to imite them and complete the circuit D D. rlhe electric circuit within the air-chamber consists, in whole or in part, of material of lower conducting-power, and therefore is of greater resistance, thanv the portions of the circuit exterior to the air-chamber; but it has such a degree of conductivity as to readily allow the passage of the current designed for this circuit; hence the operation of the apparatus under the iniluence of abnormal conditions is this: An excess ot' current produces heat in that part of the conductor which is of low conductivity, and the heat thus generated expands the air in the air-chamber and forces the globule of mercury which connects the terminals D and D/ into the receiver below, thus breaking the overloaded conductor. The chamber A, which receives the mercury when it is expelled from the air-chamber, may be closed; but it is usually provided with a small opening, which will permit the air to enter or pass out. rllhe airchamber, however, should be practically air-tight, or at least to such an extent that the expansive action of thc confined air may be utilized for the purpose described. 'Io reestablish the continuity of the conductor after it has been ruptured, as explained, the mercury has but to be agitated, with the lower chamber, A, uppermost, when it will ilow back into the air-chamber, and, the air-chamber being placed in the position shown, it will again imite the terminals of the conductor.

In Fig. III, I show substantially the same dcvice as is illustrated by Fig. I, the only change being that the wire D enters the air-chamber in the same manner as the wire D, instead of through the capillary passage.

It is manifest that the mercury or other liquid which is used to close the air-chalnber, and which is displaced by the expanding of the coniined air, may be made to effect the rupture ot' the conductor in other ways than by being, a movable part thereof, thrown out of contact with a hxed part, and the airchainber, instead of containing, might be surrounded by, coils o'f that part of the conductor intended to be especially sensitive to changes in the current.

I show in Fig. IV a modification of this character, in which the air-chamber G is support ed upon pivots g, and is surrounded by a helix, I'I, arranged in the electric circuit which the device is intended to guard. Heat generated in this helix will, by expanding the air contained in the chamber G, expel the mercury I therefrom, and cause this chamber to IOO roel; on its bearings and break the electric conductor at J, one of the contacts at this point being` of the requisite elasticity to permit the bulb G to descend. Se, also, a Inovable body of other material than mercury may be used to close the air-chamber, and may be connected with the conductor by means which shall produce a break in the conductor when the movable body is displaced by the expansion of the coniined air.

That portion of the conductor which is Within close proximity to or contained in the airehamber may, as indicated, consist of material of relatively poorer conductive power than the rest of the conductor-such, for iustance7 as platinum; but a reduction of the conductor in cross-section will effect the same condition, which is, however, not essential to the successful operation of theapparatus.

Vhat I claim as new isl. In an electric cut-out, the combination of an air-chamber, an electric conductor arranged in such proximity to said chamber that heat generated by the current will materially expand the confined air, and a movable body arranged to close said chamber and connecting with said conductor, as and 'for the purpose set forth.

2. In an elect-ric cut-out, an air-chamber provided with a capillary passage normally closed by a liquid conductor, in combination with an electric circuit arranged in such proximity to said chamber that heat gcnerated by the Acurrent will materially expand the conlined air, as and for the purpose set forth.

3. In an electric cut-out, an electric conductor composed ot' two parts of different conductivity, in combination with an air-chamber closed by a movable body, substantially 1

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7191823 *Feb 6, 2004Mar 20, 2007Avago Technologies Fiber Ip (Singapore) Pte. Ltd.Optoelectronic module and a thermal switch therefor
EP1460740A1 *Mar 20, 2003Sep 22, 2004Agilent Technologies, Inc.An optoelectronic module and a thermal switch therefor
Cooperative ClassificationH01H87/00