US2354111A - Fire detector - Google Patents

Description

July 18, 1944. A. J. GARDENHOUR 2,35411 FIRE DETECTOR Filed Dec. l, 1942 //e/ J Garden/your,

Patented July 18, 1944 f f UNITED Thisinvention relates to improvements in-fire alarm systems and apparatus. -f

The primary object" of this invention-is the provision of arelatively economically constructed fire alarm system which is foolproof and which will elimina-te the necessity of'providing watch'- men and expensive sprinkler systems. V y Other objectsl and advantages of this invention will be apparent during the course of the following detailed description. f

In the accompanying drawing", formi-ng a part of this specification, and wherein similar'reiference characters designate c'orrespondingparts:

thruout theseveral views,

j Figure lis a `perspective view ofy afnormally closed switch unit associated as p art'of' the' ,fire alarm apparatusl f u M j f Figure 2 is a longitudinal cross sectional View taken thru the `unitof Figure 1, and showing the detail'sof construction thereof. Figure 3is adiagrammatic representation of a circuit'in which the unit of Figure'lis used.

`In'the 'drawing,lwherein for .the purposeof lllustration is shown only a ypreferred embodiment of vthe invention, theletter A maygenerally des`A ig'nate the improved re alarmsyst'em whichmay include a plurality of the units B. ,A n I.

The units B, which may. appropriatelyf be termed fire detectors, are adapted to be mounted uponthe ceiling or wallsof the building to be equipped with the re alarm system, preferably one to eight square feet of the wall section. They are arranged in series and constitute a closed switch in anormally closed circuit to be subsequently described.

Each unit B preferably consists of a ilat base I0, of some approved insulation material, preferably synthetic resin, upon which detachable binding post constructions II and I2 are mounted at the ends thereof. Each of these binding post constructions preferably consists of a post body I3 having lower and upperl axially disposed screw threaded openings I4 and I5 therein. Each lower screw threaded opening I4 is adapted to receive the screw threaded shank of a countersunk head screw I5 by means of which the post body is positioned upon the base IU normal to the top surface thereof. These post bodies I3 are preferably of brass or some other approved metal, and between the lower ends thereof and the insulation base IIB, they detachably clamp metal terminals I1 upon the base. These terminals Il are of the jaw type for clamping of an end of a wire therein, and of course they extend laterally of the post bodies I3, preferably in right angled Irelation with respect to a line drawn between the two 'ports II and I2. f

. Two stamped sheet metal links' or members 20 and 2I are provided; theformer having an opening 22 in the largerend thereof adapted to receive the shank of a cap screw 23 by means of whichv the flink c'anbe clamped uponthe Post body I3`-of the Ibindingpost I I in the manner shown in Figurek 1* 'of the drawing. :The other link 2l is provided with an opening' 24 atits larger end adapted tore/ceive'one end of a coil spring 25. The 1other end-of the coil spring 25 is adapted to be clamped upon the top of the binding post body I3"by'rneans"-of aI'at-.washer 2li. and a cap screw 2l.' The screws23` and 2l, of course, are screw threaded axiallyjinto the binding [post bodies I3. lThelinks 2l)`r and 2l yare flatand taper from theiryremote endsin reducedrelation towards theirfproximate ends where' they are apertured afnd adapted'toreceive apinfrivet or connection 3D f'II'iSib ematerial, such as solder.

11n the" sition shown in Figures 1 and 2, the coil "spring, 2,5is yfurder tension so that when abnormall'temperaturesare created in the vicinity ofE theffusiblfe rivet SQILthe/same Will melt andthe l'spring,.of,course, `will.separate the links 2U and 2I-'fforbreakingfthefnormally closed circuit in whichftheunitsB are placed. 0i' courser fusible material may.beplacedlbetween the proximate ens1s-ffiher1mks2andere so desired- Referring to the Wiring arrangement of the system A, as before mentioned, the units B are placed in series, as shown in Figure 3. A magnetic relay 35 is employed. It has a wire 3G leading off from its winding connected to one end of the series of units B; the other end of the winding being connected by wire 38 to low voltage secondary 39 of a transformer 43. The wire 4I leading from this secondary 3! is connected to the other end of the series of units B. 'The source of current is established on the primary winding 4I of the transformer 451, and of course the current is completed thru the secondary winding 39 the closed units B, and the relay The latter is thus energized and attracts an armature 46 which is normally pivoted at 41. In this position the armature 46 engages a Contact 48 of a wiring circuit 49 wherein is employed a pilot light 5I). This circuit 49 of course includes the armature 46 as a part thereof and the source of current is indicated in Figure 3.

An alarm 52, which may be in the nature of a siren, has one of its contacts in the circuit 49 and its other terminal ending in a contact. 53

normally spaced from the armature 46. A spring 54 normally urges the armature 46 so that when the relay 35 is deenergized, the armature 46 will engage the contact 53 and close the circuit thru the siren or alarm 52.

It will be apparent from the foregoing, that the low voltage power supply is constant in the secondary winding of the transformer, and the circuit thru the units B is normally closed, Upon abnormal elevation of temperatures the solder or fusible alloy of the units B will melt and break the circuit. This releases the armature and sounds the alarm.

While I have shown the re detector system as operated from an outside source of supply, such as 110 volts A. C., it is possible to utilize an internal battery source of supply which is so arranged as to work relay an alarm either from a batteryY unit or direct current.

Various changes in the arrangement of the system, and in the shape, size and arrangement of parts thereof may be made to the form of invention without departing from the spirit of the same or the scope of the claims.

I claim:

l. In a fusible switch unit for re alarm systems the combination of a flat insulation base, a pair of upstanding detachable binding posts mounted upon said base in spaced relation, terminal clips connected by said binding posts directly upon the top of said base, a pair of links, fusible material connecting proximate ends of said links, means connecting one of said links in direct contact with the upper end of one of the binding posts, and means placing said links under tension and connecting the remote end of the other link to the other binding post in non-contacting relation therewith.

2. In a normally closed fusible switch unit for fire alarm systems the combination of an insulation base havinga pair of relatively spaced openings therein, a pair of binding post bodies having screw threaded openings in the lower ends thereof and screw threaded openings in the upper ends thereof, screws detachable from the bottom of said base extending thru the openings in said base and into the screw threaded openings at the lower ends of said posts for detachably connecting the said posts in right angledupstanding relation upon said base, laterally extending-electric wire attaching spring terminals clamped upon the'top of said base by the lower ends of said posts as an incident of attachment of the posts by said screws to said base, a pair of elongated connecting links, a fusible alloy connecting the extreme proximate ends of said links, one of said links being disposed over and in contact; with one of the binding posts, a screw detachably connecting said link to the top of said binding post, a coil spring, a screw connecting one end of said coil spring upon the top of the other binding post, the opposite end of said coil spring being connected with the other link and being under tension to normally move said links apart upon melting of the VVfusible material connecting said links.

3. In a normally closed fusible switch unit for re alarm systems the combination of an insulation base, la pair of binding posts mounted upon Vsaid base and extending upwardly normal thereto,

a sheet metal link rigidly and detachably mounted in direct contact with one of said binding posts, a metal spring connected in electrical contact with the other binding post having a horizontally disposed coil, a sheet metal link connected with the opposite end of said spring, and fusible material connecting the proximate ends of said links so as to maintain said horizontally disposed coil spring under tension.

4. In a normally closed fusible switch unit for fire alarm systems, the combination of an insulation base, a pair of metal binding posts mounted in upstanding normal position upon the top of said base, a pair of elongated fiat sheet metal links each having openings in each of the ends thereof, a screw inserted thru one end opening of one of said links and threaded in the top of one of said binding posts and clamping said link in laterally extending relation upon the said binding post parallel with the plane thereof parallel with the top surface of said base, a fusible rivet-like member in the other opening of said link and thru one of the openings of the other link for connecting said links, a horizontally positioned tensioned coil spring having one end connected to the other of said binding posts and its other end inserted in the other opening of the second mentioned link for holding said links under tension, the said mounting of the second link also positioning it with the plane thereof parallel with the top surface of said base.

ALLEN J. GARDENHOUR.

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