US2423537A - Fire detecting cable - Google Patents

Description

y 947. D. R. WHEELER 2,423,537

FIRE DETECTING CABLE Filed March 5, 19-43 JOC'AZ Y 1101 66 Z62" INVENTOR.

AYTORNKYI Patented July 8, 1947 uNnao STATES PATENT ornca FIRE DETECTING CABLE Dock R. Wheeler, Shreveport, La.

Application March 5, 1943, Serial No. 478,152

Claims.

My invention relates to electric circuits, and has. among its objects and advantages the provision of an improved fire detecting cable which =may be produced at a low cost, folded and easily handled without damage, and in which the cable structureis such as to provide a relatively compact construction.

In the accompanying drawings:

Figure 1 is a fragmentary view of a cable in accordance with my invention and in association with an electrically energized signal.

Figure 2 is an enlarged sectional view along the line 2-2 of Fi ure 1.

Figure 3 is a perspective view of a conductor ;for illustration, Figure 1 illustrates a conductor wire 36 enclosed in a second conductor i2 and separated therefrom by insulation 46. The insulation 46 is in the nature of a ribbon wrapped spirally about the wire 36 and the conductor I2 is of ribbon like contour and spirally wound over the insulation 46 but in a reverse direction. Both conductors 36 and i2 are of fusibie'alloy which fuses at a relatively low temperature. Such materials are well known in the art.

Asignal, such as a conventional electric bell embodying a bell i6 and the common electromagnetic operating mechanism in a housing i8, has one terminal connected through a wire 20 with the center conductor wire 36 and the other terminal connected, through a wire 22 with the exterior ribbon like conductor i2. A source of electric current, such as a battery, 24 is interposed in the wire 22. Thus, when the cable is in normal and proper condition the circuit through the bell remains open but when the cable is subjected to an abnormal condition so as to cause fusion, of the exterior conductor i2 and effect contact between the same and the inner conductor wire 36 the circuit is closed and the bell is caused to ring and indicate such fusion. The insulation is wrapped with its convolution so spaced as to provide ample clearance for fused material from either conductor to flow into contact with the other. The convolutions of the metal tape constituting the conductor l 2 are close wound so that this conductor constitutes, a housing for the insulation 46. This insulation may be cemented to the conductor 36, if desired.

On the inner face .of the conductor 12 is applied a thin body or strip 28 of noncorroding material which fuses at a low temperature. This strip acts as a protector which provides better contact between the fused conductors 36 and I2,

particularly in cases where thesetwo conductors might become corroded after a period of years. A fabric wrapper or braid 30 is applied over the conductor i2.

In wrapping the conductor l2 about the insulated conductor 36, the cable structure 26 comprises a unit line of relatively small proportions, one of which eliminates necessity of insulating and connecting as a unit two parallel conductors. The cable structure is easy to handle and may be rolled without harm to the line.

In Figure 4, the conductor 36 is provided with a ribbon 38 of spirally wound insulation. A mev tallic sleeve 40 of braided wire encloses the insulation 38, the conductor 36 and the sleeve 40 corresponding to the conductors iii and i2, re-

spectively.

The construction of Figure 5 diilers from that of Figure 6' only in that a protective sleeve 42 is applied over the conductor sleeve 40. The conductors 36 and 40 are.also fusible at low temperatures.

In Figure 6, the conductor 44 is enclosed in a covering 46 of insulating material in the nature of a ribbon close wound spirally about the conductor. The ribbon is perforated at 48 to allow fused material from the two conductors to make contact.

In Figure 7, the conductor 50 is enclosed in a braided insulating ribbon 52 wound spirally thereon. This braid is sufilciently open to permit free passage of fused material.

The covering 30 of Figure 1 may constitute fabric or metal wire. A wire covering affords protectlon against gnawing animals. Obviously all the cable devices may be enclosed in such a protective covering, with insulation provided wherever necessary. All the forms are identical with respect to the compact arrangement of the parts when considered in cross section.

Without further elaboration, the foregoing will so fully explain my invention, that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

I claim:

1. A cable of the type described comprising first and second conductors each of material for, and said insulation being provided with interstices through which fusion of the conductors will make contact therebetween.

2. The invention as in claim 1 wherein a noncorroding strip which fuses at'low temperature is provided on said second conductor.

3. The invention as in claim 1 wherein a protective noncorroding strip which fuses at low temperature is provided onsaid second conductor adjacent said insulation.

4. In a cable ofthe character described, an

inner conductor, insulation on said conductor, an outer conductor wound spirally on said insulation, and a strip of noncorroding material fusible at a relatively low temperature secured to the inner face of the spirally wound conductor, said insulation being provided with'interstices disposed to provide spacing-whereby fusing of the noncorroding and fusiblestrip will effect electrical connection between the inner and outer- N conductors.

5. In a cable of-the character described, an

inner conductor, an outer conductor, and insulating spacing meansbetween said conductor 4 provided with interstices forming separated pockets, supporting the conductors in normally noncontacting relationship; said conductors being formed of material which is fusible at relatively 5 low temperature, the insulating spacing means provided with open areas between the two spaced conductors through which the fused material of the conductors may pass to make contactwhen the fusion point in temperature of the conductors is reached.

DOCK R. WHEELER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,235,028 Harsch July 31, 1917 1,283,260 Montgomery Oct. 29, 1918 1,779,610 Lyndon Oct. 28, 1930 1 2,048,271 Lindsey July 21. 1936 1,129,358 Mitchell Feb. 23, 1915 V 1,608,18 Rumble Nov. 23. 1926 1,738,828 Jackson Dec. 10, 1929 1,962,041 Spong June 5, 1934 2,161,395 Wheeler June 6, 1939 FOREIGN PATENTS V Number Country Date France June 15, 1925

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