US1484816A

US1484816A - Thermostatic circuit-controlling device

Info

Publication number: US1484816A
Application number: US451291A
Authority: US
Inventors: John H Derby
Original assignee: Individual
Current assignee: Individual
Priority date: 1921-03-10
Filing date: 1921-03-10
Publication date: 1924-02-26
Anticipated expiration: 1941-02-26

Description

Feb. 26 1924.

I J. H. DERBY THERMOSTATIC CIRCUIT CONTROLLING DEVICE Filed March 10 1921 Patented Feb. 26, 1924.

UNITED srarias JOHN H. DERBY, OF NEW YORK, N. Y.

THERMOSTATIC CIRCUIT-CONTROLLING DEVICE. v

Application filed March' IO, 1921. Serial No. 451,291.

7 '0 all whom it may concern:

Be it known that I, JOHN H. DERBY, a citizen of the United States, residing at New York city, N. Y., have invented certain new and useful Improvements in Thermostatic Circuit-Controlling Devices,

of which the following is a clear, full, and exact description.

This invention relates to thermostatic means for controlling the starting and stop ping of motion and particularly to thermostatic electric circuit controlling means such, for example, as those employed in fire alarm and fire prevention systems.

A general object of the invention is to provide thermostatic means which is positive in operation, which may readily be constructed to operate for any desired predetermined temperature, which will have all parts so protected that dirt, moisture and other things which might tend to clog or corrode the parts are effectively excluded and which will operate with certainty even when left without inspection for many years.

A particular object of the invention is to utilize the expansible properties of some of the more readily expansible and not readily congealable liquids for eflfecting through such expansion the operation of devices of the class described and particularly the operation of circuit controlling or circuit changing devices. Other objects and important features of the invention will appear from the following description and claim when considered in connection with the accompanying drawings in which- Fig. 1 is a vertical section through a thermostatic electric controlling device embodying the present invention;

Fi 2 is a plan view of the device shown in Fig. 1 looking from below, and

'Fig. 3 is a section on the line 3-3-of Fig. 1.

In the illustrated embodiment of the invention the casing in which the movable arts are enclosed comprises a base 2 having perforated ears 4 by which it may be attached to the ceiling or other support for the device, this base having embedded there in and preferably molded therein at the time of its formation hexagonal nuts 6 which are adapted to receive the threaded ends of the screws 8 by which the circuit terminals 10 are held in osition in the device. The base 2, as wel as the other parts of the casing, is preferably formed of some insulating material such, for example, as bakelite or condensite or other phenolic condensation product.

It will be noted that the screws 8 also serve to clamp upon the base 2 a disk 12 of similar material which is provided with screw threads upon its periphery and which has upon its under face recesses in which the base portions of the circuit terminals 10 are confined by the screws 8, these recesses serving to prevent the terminals from moving out of the opposed relation in which they are shown in Fig. 1. The base 2 is slightly recessed in its end surface to receive the ends of wire clamping clips 14: of well known construction, these clips each comprising a hook 16 adapted to hook over a bared part of one of the

circuit wires

13 and 15, the wire being held against the hook by a cooperating clamp member 18 which is slotted at 20 to allow the hook 16' to pass through it. The flat inner end of clip 14 is pressed against the nut 6 by the disk 12 when the screws 8 are turned into clamping relationto the terminals 10, thus making an effective electrical connection between the terminals 10 and the

wires

13 and 15.

The disk 12 has a central opening 22 therethrough in which is guided the stem 24 of a frusto-conical circuit-closing member 26 having its lower end somewhat con caved to fit upon the convex outer surface,

of a glass or quartz cell 28 containing the expansible liquid. The stem 24 of the circuit closing member is preferably triangular in cross section so that its surface which contacts with the walls of the opening 22 is reduced to a minimum, the greatest cross sectional dimension of this stem being preferably somewhat less than the diameter of the opening 22. Between the frusto-conical member 26 and the disk 12 is located a spring 30 which presses the member 26 into them far enough apart to let this member pass between the ends 82.

A suitable liquid for filling the cell 28 is carbon. tetrachloride which is readily expansible and which does not freeze at the temperatures to which devices of this type would be subjected. As will be seen from an inspection of Fig. 1, the cell 28 is not completely filled with the carbon tetrachlo ride, the amount of air space ll provided above the liquid being varied in accordance with the temperature at which it is desired that the cell shall explode. It the cell is to explode at a low temperature the air space is obviously smaller than when the cell is to explode at a higher temperature and when, therefore. room must be provided for expansion of the liquid in the cell before the cell bursting tempeature is reached.

The cell 28 is supported in a suitable seat in an opening in the cover part 36 of the casing, which is of a hollow hemispherical, shape and is threaded upon the peripheral threads of the dish 12, thus effectively enclosing the terminals and the movable parts of the device. The opening is somewhat less in diameter than the diameter of the cell 28 whereby the major portion of the cell is not exposed to the outer atmosphere. jitter assembling the whole structure is preferably covered with a coating of waterproof varnish.

From the foregoing description, the operation of the device will readily be understood. The device being located at or near the ceiling of a room in which a the may start, the hot air rising upward will heat the cell 28, which may be made either of glass, quartz, or other material that readily conducts heat, and the liquid, such as carbon tetrachloride, which substantially fills the cell, will quickly expand and when heated to the temperature at which it is desired that an alarm be sent, the expansion of the liquid will cause the cell to be shattered. thus releasing the circuit-closing member 26 which will be moved by its spring into contact with the ends 32 of the terminals 10, thus sending in an alarm or controlling release boxes, or otherwise aid in in preventing the spread of the fire.

it will be obvious that the invention is not restricted to circuit closing, nor to the particular embodiment of the invention herein shown and described.

l-Vhat I claim as new is:

A thermostatic electric circuit controlling device comprising a quartz cell substantially filled with carbon tetrachloride, electric circuit terminals, a circuit closing member spring-pressed toward circuit closing relation to said terminals, and a support for said cell arranged to cause said cell to maintain said circuit closing member out of circuit closing relation to said terminal.

Signed at New York city, N. Y. this 7th day bf March 1921.

JOHN H. DERBY.