US2106450A - Control - Google Patents

Description

Jan. 25, 1938. K. P. BRACE 2,106,450

CONTROL Filed Aug. 21, 1956 so /2 Z2 5 4 /6 I .32 I [I 1 INVENTOR. KEMPEPP fi/mczr BY mt *f M ATTORNEYS Patented Jan. 25, 1938 UNITED STATES PATENT OFFICE CONTROL Application August 21, 1936, Serial No. 97,102

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This invention relates to controls, and is illustrated as embodied in a thermostatically-actuated mechanism for operating a switch or the equivalent.

An object of the invention is to provide a sensitive operating mechanism which can easily be adjusted. It is diflicult to adjust control mechanisms of this type when they are actuated by the expansion of a fluid against the inherent resistance of a metallic bellows on which the fluid acts, such adjustments involving changes in the mounting of the bellows, and being afiected by difierent characteristics of different bellows. It is extremely diflicult to make such bellows with characteristics which are even approximately uniform.

According to the present invention, a lever or the like which actuates the switch is engaged by a'metallic expansible chamber (such as a wafer made up by uniting the margins of two metal disks) which is deliberately made up to have relatively little resilience.

The yielding resistance is supplied by means such as a leaf spring secured to and extending from the end of the lever. This spring is flexed by the expanding fluid against a stop such as a setscrew adjustably threaded into a bracket or the like adjacent the end of the spring. The device is readily adjusted by changing the setting of this stop.

The above and other objects and features of the invention, including various novel arrangements and desirable constructions, will be apparent from the following description of the i1- lustrative embodiment shown in the accompanying drawing, in which:

The figure is a side elevation of the control, with the expansible chamber broken away in section.

In the illustrated arrangement, a suitable base II] has mounted thereon a switch H, of any desired type, shown as actuated by a plunger H. The plunger I4 is engaged by a vertical part l6, having a relatively short throw, of a bellcrank lever having a horizontal arm l8, and fulcrumed on a pivot 20 carried by the base Ill.

The arm 18 has an upwardly-oifset portion 22 engaged by an expansible chamber 24, deliberately constructed to have relatively little resilience, and containing the usual volatile expanding operating fluid. If the entire device is mounted at the point whose temperature is to control the switch, the chamber 24 vmay be sealed; or if there is to be a control from some remote point, the chamber may be connected by a conduit 26 with a bulb or the like at the point whose temperature is to control the switch l2. part 24 may be made by soldering or welding or otherwise securing together the margins of two disks, preferably of light-gauge metal.

A leaf spring 28 is riveted or otherwise secured to the end of the lever I6l8-22, to form an extension thereof. Springs of this character are readily made with substantially uniform characteristics. The end of this spring bears against an adjustable stop such as a setscrew 30 threaded through a bracket 32 mounted on the base l0. Thus expansion of the operating fluid flexes the spring 28 against the stop 30, and the device is readily adjusted by changing the setting of this stop.

As the arm l822, plus the spring 28, forms a very long lever arm, the adjustment is very sen- U sltive. This is important, as the expansion of the device 24 which actuates the switch is a very small amount, necessitating extremely accurate setting of the resistance against which 0 it operates.

While one illustrative embodiment has been described in detail, it is not my intention to limit the scope of my invention to that embodiment, or otherwise than by the terms of the appended claims.

I claim:

1. A thermostatic control or the like comprising a switch, a pivoted lever having on one side of its pivot a part with a relatively small throw arranged to actuate said switch, an expansible 30 chamber engaging said lever on the other side of the pivot from said part and containing an operating fluid and having relatively little inherent resilience, a leaf spring secured to and forming an extension from the end of said lever 35 on the other side of the pivot from said part, and an adjustable stop engaging the spring some distance beyond the end of the lever and against which the spring is flexed by expansion of said chamber by the fluid. 40

2. A thermostatic control or the like comprising a switch, a pivoted lever having on one side of its pivot a part with a relatively small throw arranged to actuate said switch, an expansible chamber engaging said lever on the other side '45 of the pivot from said part and containing an operating fluid and having relatively little inherent resilience, a leaf spring secured to and forming an extension from the end of said lever on the other side of the pivot from said part, a 50 bracket adjacent the end of the spring, and an adjustable setscrew threaded into said bracket and engaging the spring some distance beyond the end of the lever and against which the spring is flexed by expansion of said chamber by the fluid.

KEMPER P. BRACE.

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