US2438109A - Temperature control device - Google Patents

Description

March 23, 1948. F. D. BENNETT E! AL TEMPERATURE CONTROL DEVICE Filed June 3, 1944 2 Sheets-Sheet 1 FIG. I

FIG.3

FIG. 4

K nm M m T W M 7 E V W M KQA r K 1m CS l! mA 4 EM I DO M FT Y March 23, 1948. 1:; BENNETT ET'AL 2,438,109

TEMPERATURE CONTROL DEVICE Filed June 3, 1944 2 Sheets-Sheet 2 'INVENTOR. FREDERICK D.BENNETT BYTHOMAS A. NEWKIRK FIG.5

Potented Mar. 23, 1948 TEMPERATURE CONTROL DEVICE .Frederick D. Bennett, Dayton, and Thomas A.

Ncwkirk, Fairilcld, Ohio Application June 3, 1944, Serial No. 538,876

1 Claim.

(Granted under the m of March a, me, as amended April 80, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

The invention to be hereinafter described relates to temperature activated couples for controlling switch operation.

It is common practice to control the operations of switches, valves and other devices by bimetallic couples in which the two metallic elements, having diii'erent coefllcients of expansion, apply that difference to control the operation; One reat objection to such bimetallic couples is that they frequently produce chattering or irregular action. The present invention completely eliminates this serious objection and, at the same time, provides a simple, compact, economical and highly eflicient positively acting couple.

In order to more clearly disclose this construction, operation and use of the invention, reference should be had to the accompanying drawings forming part of the present application. Throughout the several figures of the drawings like reference characters designate the same parts in the different views.

In the drawings:

Fi 1 is a front elevation;

Fig. 2 is a top planview of Fig. 1, top of casing being indicated in dotted lines;

Figs. 3 and 4 are, respectively, enlarged fragmentary front elevations of the end portions of Fig. 1, Fig. 3 being partly broken away; and

Figs. 5 and 6 are cross sections on lines 5-5 and 86, respectively, of Figs. 3 and 4 respectively.

Referring to the drawings in detail, I is a suitable box-like casing or frame, preferably of aluminum. As shown, this case is substantially rectangular and shallow, though both the sha and dimensions may vary considerably within a considerable range. Within this caseis disposed an into the rear wall of the casing at a point a short distance from the elbow or bend. Due to this connection, movement of easing I, due to temperature change, either expansion or contraction, will carry lever 2 with it. That, of course, will cause no movement of lever 2, relative to casing I. In

the lower part of the casing below and approximately parallel with the long arm of lever I, is a porcelain rod 4 of substantially the same length as the long arm of 2. It is positively anchored, at one end, to the corresponding end of casing l and therefore, moves only by and with that end of the casing. The coeflicient of expansion of porcelain is, of course, difierent and much lower than that of aluminum. In assembled relation, with rod 4 and the long arm of 2 approximately parallel, one end of rod 4 just contacts the adiacent face of the lower end of the short arm of 2. In that position, if there were no connection between 2 and 4, expansion of l due to increase of temperature could simply carry 2 with it away from theadjacent end of 4. By definitely anchoring the end of l to the adjacent end of the short arm of 2 by a screw 8 passed through it and into the end of l, the rod 4 acts as a stop or anchor, preventing the free travel of the lowerend of that short arm with the casing I. Since rod 4 elongates less than casing I for the same rise in temperature, this connection will cause lever 2 to rock on its pivot 3, raising the free end of the long arm of 2 from the push button or pin 5 of a well known type of micro-switch 8 suitably mounted in well known manner in casing i. This, in turn, will make or break, as may be desired, the circuit controlled by the micro-switch. For adjusting the micro-switch to operative position where it will be activated by lever 2, the threaded rod 9 through aluminum block I0, is provided.

In order to provide the necessary free rocking movement of the contacting ends of l and 2, the end of 2, both where it contacts 4 and where it contacts screw 8 is curved or rounded as at 1.

While porcelain and aluminum have been particularly set forth as materials involved in the couple of this invention. the invention is not limited specifically to them. They have been found to eliminate the chatter objection found in bimetallic couples. Other non-metallic materials such as certain plastics for instance, may be used in place of porcelain, the essential being the relative coeilicient of expansion as between such selected material and the metallic material used and the relative characteristics of their expansions.

Many changes may be made in the construction, arrangement and disposition of the various parts of the invention, within the scope of the appended claim, without in any degree departing from the field thereof and it is meant to include all such within the application wherein only one preferred form has been disclosed by way of iiiustration and with no thought or intention o! limiting the invention thereby.

Having thus described our invention, what we claim and desire to protect-by Letters Patent is:

In a device of the character described, a metallic case, a bell-crank lever carried by said case and pivotally mounted therein, a rod having a coeflicient of expansion difl'erent than that or said case and anchored at one end to that end of the case remote from the lever pivot, one end of said lever having opposed convex surfaces one 91' which contacts the free end of the rod and adjustable, threaded fastening means passing through said convex surfaces into said rod, said fastening means being loose enough to allow continuous, tree-sliding. rocking, surface-contact of the lever on-and between said rod and fastening means.

FREDERICK D. BENNE'I'I'.

THOMAS A. NEWKIRK.

4 nmnncns 01m The iollowing references are 0! record in the file of this patent:

5 UNITED STATES PATENTS Number Name Date 1,075,991 Ruud Oct. 14,1913 1,111,789 Freas Sept. 29, 1914 1,703,283 Smith Feb. 28, 1929 1,857,025 Hurxthal. May 3, 1032 2,033,410 Dezotell Mar, 10, 1936 2,080,661 Hill May 18, 1937 2,185,623, Beam Jan, 2, 1940 15 FOREIGN PATENTS Number Country Date 53,709 Germany Oct. 1, 1890 466,477 Germany Mar. 13, 1926 700,112 France .....1 Dec. 22, 1930

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