US1858660A - Thermostatically controlled heating device - Google Patents

Description

May 17 1932- R. w. BROWN THERMOSTTICLLY CONTR/OLLED HEATING DEVICE Fild Nov. 25 1927 INVENToR. Fm Y WE R 1:: WN-

' ATTORNEYS.

Patented May 17, 1932 UNITED STATES ROY W. BROWN, OF AKRON, OHIO, .ASSIGNOR TO THE FIRESTONE TIRE AND RUBBER COMPANY, OF AKRON, OHIO, A CORPORATION OF OHIO THERMOSTATICALLY CONTROLLEI) HEATING DEVICE Application filed November 25, 1927.

This invention relates to electrically heated devices controlled by means of a thermostat.

An object of the invention is to devise a thermostatically controlled heating device wherein the thermostat is interposed between the heating coil and the element to be heated. Another object is to devise a 'thermostat comprising a bi-metallic element which is free to contract at temperatures below operating heat. A further object is to devise means for causing the Contact points of a thermostat to slide over one another as the Contact isbroken.

The foregoing and other objects are obtained by the device illustrated in the drawings and described below. It is to be understood that the invention is not limited to the specific form thereof disclosed herein.

Of the accompanying drawings,

Figure l is a side elevation of a device embodying the principles of the invention;

Figure 2 is a vertical sect-ion thereof; and

Figure 3 is a transverse section taken on the line 3 3 of Figure 2.

For purposes of illustration, the invention has been embodied in a branding die heater, but it equally is adapted for use in soldering irons, fiat irons, melting pots, or any other electrically heated device. The device illustrated comprises a shell 10 to which is attached a socket member ll for holding the branding or embossing die l2 or other element to be heated. A sleeve 13, rotatable about member l1 is provided with bayonet slot-s 14 for engaging bayonet lugs l5 on die l2 to secure the latter in the socket. The heating element is in the form of a coil 16 wound about a tube 17 positioned Within shell l0, the heat being transmitted to the die through a rod 18 of copper or other good heat conductor projecting into the die and extending within tube 17. One end of the coil connected to the electric terminal i9 and the other end is connected to one Contact point 2O of a thermostatically operated circuit breaker. 'The second electric terminal 2l is connected to the other contact point 22 t irough an arcuate leaf spring 23 fixed at one end to post 24, the tension of the spring serving to urge the contact points together. An arcuate Serial No. 235,445.

loi-metallic strip 25 is also fixed at one end to post 2% and is positioned within spring 23 and adjusted so that when the desired temperature of die l2 is obtained, strip 25 will expand sufiiciently to engage spring 23 and separate the points 20 and 22 as shown in the dotted lines in Figure 3 to break the circuit. As the contact is broken there is a` tendency for one point to slide over the other slightly, this wiping action serving to keep the contact surfaces clean. l/Vhen the temperature falls below operating heat, strip 25 contracts and spring 23 forces the contact points together re-establishing the circuit. Since the bi-nietailic strip is separate from the contact spring, the former is free to contract Without stress when use of the device is discontinued and the heat decreases to normal room temperature. Thus there is no tendency for the iii-metallic strip to be bent outwardly to lose its adjustment upon cooling. Greater uniformity of operating temperature is obtained by so constructing the thermostat and by interpcsing the same between the source ofheat and the element to be heated as disclosed.

Modiications of the structure disclosed herein may be resorted to without departing from the spirit of the invention or the scope thereof as defined by the appended claims.

What is claimed is:

l. A device of the class described comprising a pair of relatively movable contact points, means for yieldingly urging said points into contact to establish an electrical circuit, and means expandible by heat for sliding one contact point over the other to clean the surfaces thereof, and for separating said points to break said circuit.

2. A device of the class described comprising a pair of relatively movable contact points, an arcuate spring upon which one of said points is mounted and yieldably urged against said other contact point to close an electrical circuit, and an arcuate bi-metallic strip expandible by heat and engageable laterally of' said arcuate spring to cause one contact point to slide over the other and to separate the points to open the electrical circuit.

ROY W. BROVN.

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