US339485A - Fire-alarm transmitter - Google Patents

Description

(No Model.)

W. 0. S HAFFER.

FIRE ALARM TRANSMITTER.

PatentedApr. 6, 1886.

UNITED STATES PATENT OFFICE.

IYILLIAM C. SHAFFER, OF CHICAGO, ILLINOIS.

FIRE-ALARM TRANSMITTER.

SPECIFICATIQN forming part of Letters Patent No. 339,485, dated April 6, 1886 Application filed August 24, 1885. Serial No. 175,132. (No model.)

To all whom, it may concern:

Be it known that I, WILLIAM C. SHAFFER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Fire-Alarm Transmitters; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accom' panying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

This invention relates to fire-alarm transmitters, by which an alarm of abnormal heat is sent over an electric or other equivalent line to a distant station, and has special reference to such transmitters in which the send ing of the signal is dependent upon the melting or partial melting of a material whose melting-point is approximately equal to the temperature of which it is desired to give notice.

In the accompa'nyiug drawings, Figure 1 is a plan of one of my improved transmitters. Fig. 2 is a plan of the same with the cover removed. Fig. 3 is a side elevation when the cover is removed. Fig. a is a vertical section through the center of the transmitter. Fig. 5 shows a modification of the instrument.

A is a base of wood or other material, upon which the operating mechanism is mounted.

B B are binding-posts, for securing the circuitwires C C.

D is a yielding electrode or pole, electrically connected with the bindingpost B.

D is a swiveled bar electrode, electrically connected with the bindingpost B, and having one end adapted to move into or out of contact with the free end of the electrode D. This bar may be made in a variety of forms. In the drawings one end thereof is in the form of a segment of a circle, having teeth (2 on the periphery, while the other end has an eye, and the middle thereof is loosely pierced by the vertical screw or post 01, which latter is firmly seated in the base A, and electrically connected with the binding-post B.

E is a spring, attached by one end to the base A,and by the other to the bar D, at the end opposite the point of contact. Said spring,

when unhindered, turns the bar D in the direction of the arrow in Fig. 2.

It will readily appear that when the bar D is moved or rotated about the post d the circuit will be made and broken as many times as there are teeth on said bar, and that the contacts will be made by the teeth (1 sliding over the surface of the electrode D, thereby pushing aside any foreign matter on the contactpoints and insuring a closing of the circuit. By using a series of teeth, d, each designed to make a circuit in its turn, I am the more certain of making the circuit, for if a portion of the teeth should fail I can rely on the others.

Instead of arranging the teeth in a regular series,- they may be grouped after the manner of a recording-telegraph, in order that the number of the heated transmitter may be sounded or recorded at the station. When these teeth are thus grouped, or when they are arranged in a regular series, it is essential that the bar D move slowly and with an approximatelynniform motion, in order that the breaking and making, and making and breaking, of the circuit may be sufficiently slow to allow the sounding or recording mechanism at the station to act.

In preparing the transmitter for action I turn the bar D to its farthest limit in the direction opposite that indicated by the arrow, and then placea mass of fusible retarding material, F, consisting of rosin, shellac, or other substance which melts at the desired temperature, and which becomes viscous on melting, on the surface of the base A, in front of the bar D. This mass of fusible material retains the bar D in position until the melting heat is reached, whereupon it softens sufficiently to allow the bar D to move slowly under the pressure of the spring E. Any material which would promptly liquefy on melting would of course allow the bar to move instantly. Therefore for my purpose I avoid the use of such material.

In experimenting I have found that in some situations the rosin or shellac F will yield prematurely to the pressure of the spring E. In such cases I re-euforce the rosin or shellac with a plug, F, made of a low-fusion metal alloy. Such plug holds the bar D positively until the chosen temperature is reached, whereupon it yields abruptly and allows the rosin or shellac to retard or govern the movement of the bar.

G is a cover, having in its face the holes g, and about its circumference the flange g to embrace the base A. Said cover serves as a protection for the inner mechanism, and the holes 9 serve to facilitate thepassage of heat to the fusible material within. Said cover may be immovably attached to the base A; but

I prefer to secure it thereto by a readily-fusible material, G, in order that the cover may be released and allowed to fall by its gravity,

the transmitter being usually attached to the ceiling with said cover directed downward, thus more effectually exposing the inner mechanism to the heat. It is desirable, also, to have these covers fall, in order to readily show which particular transmitter was sufficiently heated to give an alarm.

It is obvious that in most cases the material G will melt and yield before the material F will, even when the two are of the same kind, for the reason that the material G is first exposed to the heat; but if it is desired to hasten the fall of the cover, the material G may be made of a lower melting point than the materials F and F.

In this class of instruments oxidation and corrosion frequentlyinjure the metallic parts, and particularly the contact-points and the alloy plugs, the latter sometimes becoming harder and sometimes softer, and sometimes raising and sometimes lowering (depending upon the ingredients of the alloy) its meltingpoint. In many cases the transmitters must be located in moist places and places abounding in corrosive gases,where the oxidation and corrosion are a constant annoyance. To overcome this, I take the transmitter when set ready for action and dip it into liquid parafiine. This covers every part with a layer which is proof against the action of these destructive agents, and which is so much softened by abnormal heat as to allow the free action of the movable parts of the transmitter. As the parafline is a non-conductor, it can in no way interfere with the circuit.

The instrument is usually attached, face downward, to the ceiling, but it may obviously be placed in other positions. It is obvious, also, that a weight may in some cases be substituted for the spring E. In Fig. 5 the bar D is itself weighted and so mounted as that it will move of itself when the material F has become sufficiently softened.

I claim as my invention- 1.' The combination of a movable multicontact electrode and a fusible plug applied directly to said electrode, substantially as shown and described.

2. The combination of a movable electrode and a retarding material for controlling the movement of said electrode, substantially as shown and described.

3. The combination of a movable electrode, a spring or weight to actuate said electrode, and a mass of material which is normally solid and holds said electrode out of action, but which becomes viscous or semi-solid from abnormal heat, whereby the electrode is retarded in its movement, substantially as shown and described.

4. The combination of a. movable multicontact electrode, a spring or weight to actuate said electrode, and a mass of material which is normally solid and holds said electrode out of action, but which becomes viscous or semi -solid from abnormal heat, whereby the electrode is retarded in its movement, substantially as shown and described.

5. The combination of a movable electrode, a spring or weight to actuate said electrode, and a mass of material which under abnormal heat changes abruptly from the solid to the liquid form, and a material which becomes plastic or viscous under abnormal heat, substantially as shown, and for the purpose set forth.

6. The combination of a movable multicontact electrode, a spring or weight to actuate. said electrode, and a mass of material which under abnormal heat changes abruptly from the solid to the liquid form, and a material which becomes plastic or viscous under abnormal heat, substantially as shown,and for the purpose set forth.

7. The combination of the base A, electrodes D D, spring E, and material F, which becomes viscous or plastic under abnormal heat, substantially as shown and described.

8. The combination of the base A, electrodes D D, spring E, material F, which becomes viscous or plastic under abnormal heat, and the alloy F, which changes abruptly from the solid to the liquid state, substantially as shown, and for the purpose described.

9. The combination of a movable electrode,

an alloy plug to stay said electrode, and an oxidation and corrosion proof coating for said alloy plug, substantially as shown and described.

ICO

fall, thereby more effectually exposing said a transmitter to the action of the heat, substantially as shown and described.

12. The combination, with the base A, electrodes D D, spring E, and fusible material F, of a cover, G, held in place by a ma- .WILLIAM C. SHAFFER.

Witnesses:

OYRUs KEHR, CHARLES H. ROBERTS.

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