US2527875A - Thermostatic switch - Google Patents

Description

Oct. 31, 1950 J. H. BRUHN ErAL lrmmos'xwrrc swrrcu Filed lay 28, 1948 Patented Oct. 3l, 1950 UNITED THERMOSTATIC SWITCH John H. Bruhn, Des Moines, Iowa, and Leonard W. Bruhn, Kansas City, M0.

Application May 28, 1948, Serial No. 29,864

4 Claims.

This invention relates to thermostats and an object thereof is to provide a two action thermostat.

Another object of the invention is to provide a double duty thermostat.

A still further object of our invention is to provide a thermostat for operating both visible and audible alarm systems.

A further object of this invention is to provide -a thermostat so constructed that it will operate rst one and then another alarm system.

Another object of the invention is to pro-vide a thermostat to alternately operate a plurality of alarm systems.

Another object of this invention is to provide a thermostat having adjustable means whereby it may either open or close electric alarm systems at predetermined atmospheric temperatures.

A still further object of our invention is to provide a thermostat formed of a bimetallic bar each end of which is adapted to control an independent electric system.

Still another object of the invention is to provide a thermostat formed of a bimetallic alloy metal bar having a long and a short arm each adapted to actuate at different degrees of temperature to open or close independent electric circuits.

With the above and such other objects in view as may hereinafter more fully appear, we have invented the thermostat illustrated in the accompanying drawings in which:

Figure l is a sectional elevational view of our thermostat,

Figure 2 is a longitudinal sectional view of the thermostat shown removed from its casing,

Figure 3 is a bottom plan view thereof,

Figure 4 is an enlarged detail view of an indica tor.

Figure 5 is an end view showing high and low contact.

In the following specification as well as in the accompanying drawings like reference characters indicate like parts throughout and in which I0 refers to our thermostat as an entirety and I I indicates a non-conductor base. Attached to the up per surface I2 of this base is a bimetallic bar I3,

vwhich is bent down intermediate its ends to form a seat Il which is secured to the upper surface I 2 of base IIv by bolts I6 and I6'. Said seat III is formed nearer the short arm II than the long arm I8 of bar I3 for a purpose presently to be explained.

A contact screw I9 is threaded through one end 20 of the base II and its point 2| seats directly beneath the extreme free end 22 of arm` I9. Mounted on the screw I9 is a conductor 23 and a lock nut 24, and secured to the under surface of the base I I ls the arm 25 by means of said conductor or otherwise. The arm 25 terminates in an indice pointer 26 which is turned up to the under surface 21 of the enlarged head 28 of said screw I9 and which surface is provided with indicia to indicate various temperatures at which the screw I9 may he set to either attract (or repel, as the case may be) the said terminal 22 of arm I8.

Mounted directly under the terminal 29 of the short arm I'I of member I3 is a conductor screw 30 on which is mounted a conductor 3|, a lock nut 32, an indice 33 and indicia head 3l, similar in all respects to the arrangement of screw I9.

Fixed to the base II adjacent its end 20, is c bracket 35 the upper end 36 of which is bent at right angles to extend over and above the said terminal 22 of arm I8. Threaded through sar end 36 is a conductor screw 3l having an indici:L head 38 and a contact point 39 which may be adjusted to contact (or leave) the arm I8 at a predetermined temperature.

The base II is mounted within a housing 40 which may be of any suitable material such as tin or lava, and it is provided with a series of apertures 4I above the base, and apertures 42 below the base, which base is provided with bores I3, whereby a free circulation of atmospheric air may be constantly in the housing.

The above described thermostat has been designed primarily for a combination of audible and visible fire alarm systems and rst gives an alarm in the building Where located due to the more flexible action of the long arm I8. The shorter arm IT being more rigid requires greater heat to actuate it and this arm is connected up with a general alarm system connected with a re house or other central point. Therefore if a fire is not extinguished after the first alarm the heat raises and actuates the second system.

The device is also adapted to operate signals at predetermined low temperatures as for use in orchards, cold storage plants, etc. In this latter case the screw 31 is connected with the circuit which preferably operates on an open circuit for activating signals when a predetermined low tempcrature is reached.

Having now described our invention that which we claimy as new and desire to procure by Letters Patent is:

l. In an alarm thermostat having a base, circuit conducting means and a bimetallic thermoasoman static bar, a plurality of contact arms comprising said bar, each oi said arms being of diiierent lengths and having one extremity amxed to said base then extending upwardly to form an acute angle with said base and then outwardly in a plane substantially parallel to said base to form an obtuse angle with said upwardly extending portion.

2. An alarm thermostat comprising a bimetallic thermostatic bar having a plurality of contact arms of diiierent lengths, points at which said arms make contact with a circuit conducting means and control indicia to regulate the exact temperature at which said contact as between said arms and points is to be made, the contact arms of said bi-metallic bar having one extremity afiixed to said base and then extending upwardly to form an acute angle with said base and then outwardly in a plane substantially parallel to said base to form an obtuse angle with said upwardly extending portion.

3. An alarm thermostat comprising a bimetallic thermostatic bar having a plurality o! contact arms of diierent lengths, points at which said arms make circuit contact, a plurality of -said points being positioned below said bar and one of said points being positioned above said bar, and control indicia to regulate the exact temperature' at which said contact as between said arms and points is to be made, the said contact arms of said bi-metallic par having one extremity afilxed to said base and then extending upwardly to form an acute angle with said base and' then fcuit conducting means and a bimetallic thermostatic bar having a plurality of contact arms, a plurality of circuit contact points positioned below said arms, one circuit contact point positioned above one oi said arms, and control indicia to reilulate the exact temperature at which said contact, as between said arms and said points, is to be made,- the said contact arms ot said bi-metallic bar having one extremity aiiixed to said base and then extending upwardly to form an acute angle with said base and then outwardly in a plane substantially parallel to said base to form an obtuse angle with said upwardly extending portion.

JOHN H. BRUHN.- LEONARD W. BRUHN.

REFERENCES CITED The following references are of record in the ille oi this patent:

UNITED STATES PATENTS

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