US555069A - Thermostat-actuated alarm - Google Patents

Description

' (No Model.)

11-13. BIGELOW. THERMOSTAT AGTUATED' ALARM.

No. 555,069. I Patented Feb. 25, 1896.

A TTOHNE).

UNITED STATES FRANK B. BIGELOIV,

PATENT OFFICE.-

OF AUBURN, MAINE.

TH ERMOSTAT-ACTUATED ALARM.

SPECIFICATION forming part of Letters Patent No. 555,069, dated February 25, 1896.

Application filed September 6, 1895. Serial No. 561,674. (No model.)

To aZZ whom, it may concern.-

Be it known that I, FRANK B. BIGELOVV, a citizen of the United States, residing at Auburn, in the county of Androscoggin and State of Maine, have invented certain new and useful Improvements in Thermostat-Actuated Alarms, of which the following is a specification.

My invention relates primarily to alarms which are used in connection with dentists vulcanizers, but is useful for other purposes. It belongs to that class of thermostatic devices in which a compound metallic bar is placed in contact with the walls of a heated chamber, is acted upon by the heat transmitted through these walls, and is adjusted to indicate a certain definite temperature of the interior of the chamber. An alarm of this general character is the subject of application Serial No. 498,268, filed January 27, 1894, by F. B. Bigelow and V. P. Buck.

. The object of my invention is to provide a device which shall be applicable to dentists vulcanizers of all styles and shapes, shall be easy to adjust accurately, and little liable to derangement.

In the accompanying drawings, Figure l is a side elevation of the machine; Fig. 2, an end elevation.

In the drawings, A is the compound metallic bar which serves at the same time as the supporting-framework of the device and its actuating thermostat.

The bar A is made'u p of a relatively-thick inside strip, 17, of brass, and an outer relatively-thin strip, 0, of steel, which is united with the brass by soldering and riveting. At one end the brass strip 1) extends beyond the steel and is bent inward to support the alarm D, which, as shown, is an ordinary clock-alarm released by the detent d, which presses against the wedge-shaped part 10 of the releasing-rod R. This rod passes through the brass strip 1), and its T-shaped head II is pressed against the grooved back of the strip Z) by the spring "1). The other end of R is notched and rests upon the adjusting-screw S, which is turned by the thumb-piece h. The rotating stop t,which surrounds the shank of the adjusting-screw and has a projection against which the thumb-piece h strikes, is

Figs. 3 and 4 show details.-

held in place by the two clamping-screws m and n. l

The dotted outline R in Fig. 1 shows the position of R after it has been released by the expansion of A. R in Fig. 4: shows its position when swungto one side for replacement.

'I/Vhen I wish to make use of my invention I place the device upon the upper surface of a vulcanizing-chamber, which is then brought to the desired temperature and kept there for a short time. The adjusting-screw S is then carefully turned back until it releases the rod R and thereby the alarm D. The rotating stop 15 is then brought up against the thumb-piece h and clamped by the screws 4% and n. The rod R may now be replaced by swinging it around the point of the adj ustingscrew S, as shown in Fig. i, and if desired the screw S may be turned in a little, when the alarm will not go off until the chamber has reached the corresponding temperature. The number of degrees corresponding to any fractional part of a revolution of the screw is 4 readily determined by observation.

By turning the thumb-piece h back against the rotating stop 25 the release of the alarm is brought back to its original point.

By the use of the rigid releasing-rod R, held in place by the spring S, I am enabled to adjust the instrument very closely to a given temperature, and to depend upon its remaining in adjustment thereafter, since the rod R drops clear when released without any tendency to grind off the point of the adjusting-screw S, while if caught upon the point of S when A contracts the spring '0 yields and prevents damage.

Having now fully described my invention and the manner of using it, what I claim, and desire to secure by Letters Patent, is

1. In a thermostat-actuated alarm a compound metallic bar having a flat part of sufficient length and breadth to serve as a base for the alarm and two ends which bend upward at right angles to the base, in combination with an adjustable connection for the two ends which drops apart when the two ends are swung out by the unequal expansion of the bar; all as set forth.

2. In a thermostat-actuated alarm, a compound metallic bar which serves as a support for the device and turns upward at the ends, a continuation of one of the strips of the bar upward and inward, a spring-driven alarm attached to this continuation, and means of releasing this alarm by the outward motion of the ends of the compound bar; all as set forth.

3. In a thermostat-actuated alarm a compound metallic bar whose ends swing outward by expansion; an adjusting-screw passing through one of these ends; a T-headed rod passing; through the other end and resting upon the ad jnsting-screw, and a spring pressing the T-head of the rod against the outside of the compound bar; all as set forth.

at. In a thermostat-actuated alarm, a sprin gdriven alarm controlled by the expansion of a compound bar, an adjustin -screw which determines the point of release of the alarmdetent, a flat thumb-pieee for turning this screw, a rotating" collar bearing a stop for the thumb-piece surrounding the stem of the adjusting-screw, and one or more screws which hold the collar in position; all as set forth.

In testimony whereof I have hereunto set my hand this 3d day of September, A. D. 1805.

FRANK ll. BIGELOXV.

\Vitn esses:

FOREST E. LUDDEN, FANNIE V. SAUNDERS.

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