US2798134A - Thermostat - Google Patents

Description

July 2, 1957 C. D. GEER THERMOSTAT Fird Dee. 9, 1954 INVENTR haras er M www m ATTORNEYS United States Patent THERMOSTAT;

Charles'D. Geer, East Orange, N. JL, assignor to G`V Controls,` Inc., East Orange, N. J., a corporation of New Jersey` Application December'9, 1954,'l SerialNo. 474,090;

4'Claims; (Cl. 20.0-137) This invention relatesf to a'thermostat structure which will present an arrangement of'parts alternative over-.that 'disclosed inthe prior U. S. patentto WilliamC. Broekhuysen 2,664,483, dated December 29, 195 3;

More particularly,by the-.presentteachings,it will be unnecessary to resort-to a constriction ofthe. outer casing tube as disclosed in the aforementioned patent. Thereforea structure is furnishedwhich will lend'itselffftoeconomical and quantity production. At thesame time, adequate and simple adjustments may be readily resorted to irl-order to vary the operating point ofthe instrument as required.-

Attention isA invited` to the attached'` sheet?. of. drawings illustrating one practical embodiment of .the'inventionl and in which:

Figure 1 is a sectional side,.view-- ofY an assembly with the parts thereof in one position;

Figure 2 is a similar view with the partsl adjusted to a second position;

Figure 3` is aV face view taken. alongitheline 3-3' inthe Idirectionof-the arrows asindicatedfinFigure 2;

Figure 4. is a transverse sectionalview in enlarged scale taken along the Iline 4 4 in the direction of the arrows as indicated in Figure 1;

Figure 5 is an exploded perspective view showing the internal structure of the assembly.

In these Views the number indicates a tubular casing conveniently formed of brass. Contrary to the disclosure of the prior Broekhuysen patent, the lower end of the casing is not spun down to smaller diameter nor is it ilattened. One end of the casing is conveniently closed by a cap or end piece 11 from which insulated terminals 12 and 13 extend. The opposite end of the casing is in the embodiment illustrated closed by a removable cap 14. Recessed within the latter casing end is a disc or washer 15 which is preferably cup-shaped and formed with a central slot. Closure 11 is secured against detachment with respect to the casing. This is also true of washer 15. The latter is conveniently brazed to be locked against axial shifting.

Extending through the slot of the washer 15 is a strip or tail piece 16. This may again be brazed to that washer. A channelled or flanged strut 17 is exibly connected in any suitable manner with strip 16. Preferably both of these latter elements are formed of a metal having a low coefficient of expansion. The upper end of -strut 17 is secured by spot welding or otherwise to the inner face of the casing at a point remote from washer 15 and as indicated at 18. The strut ilanges extending from both of its side edges have been indicated at 19.

At a point substantially midway of the strut, its body is inclined at an angle to the axis of the assembly; this having been indicated at 20. In this manner, the end zone 18 of contact between the strut and the casing will be established. At a point in line with the juncture of the strut parts 17 and 20, flanges 19 may be interrupted by a V-shaped notch 21. Also, in this zone an opening 22 may '2,798,134 Patented July 2, 1957 be .formed in the strut body. By that procedure a vpoint'or zone of ilexure is provided.

Secured to strut.17 adjacent this .zone is one end of a spring strip 23. The upperend of this spring. carries a bar 24. The spring has its lower endsecured to the strut preferably by spot welding. Similarly secured to the strut 17 ata point short of the zone'of flexure are a pairY of arms 25. These arms extend through the zone of the vbar or terminal portion 24of spring 23 and. prevent movement of that spring in a clockwise direction beyond a predetermined point.

Terminal 12A carries acontactf26. A cooperating contact,27 is also provided.. The latter contact is` mounted upona. rod 28 supporting. an insulatingl member which is preferably inthe form-of a bead.29of glass or similar material.y The rod may be'attened as at 30 to provide a resilient andflexible portion'. The .lower end of the latter is securedtoan extension 31 of terminal 13.

Having in mind the diierence in the coefcient of. expansion between the material of casing 10 and at least certain of the operating parts of the remainderl of the assembly, itwill be appreciated that as variations in temperature occur the expansion and'contraction of these operating partswill not be the same as that of the casing. The extremities ofthe operating assembly are in effect secured against movement with respect to the casing. Therefore, movement will occur adjacent the zone of ilexure. That'movement willbe in the form of a rocking ofstrutaportion 20, the spring 23 andthe-arms 25. The resistancetomovementon the part'of spring 23 is substantially greater than .that ofthe llexion strip 30. Therefore, asithismockingoccurs :in one direction', bar124'will engage bead29 to rock rod 28 so thatcontacts26landt27 willbe separated as in Fig. 1. As tlieparts move in a reverse directi'on, bar-,24 will shift to the left as in Figs. 1 and 2 to a pointwhere contacts26 and 27fwill engage. With such engagement, the circuit through terminals 12 and 13 will be completed.

As has been brought out in the Broekhuysen patent it may be necessary to adjust the operating point of the thermostat so that the 'circuit controlled by the same will open at a higher or lower temperature than Would result from the relationship of the parts as initially established. To make such adjustment, the tail piece or strip 16 should be shifted to extend in a slightly ditlerent direction than -exists in the original assembly. By means of the present teachings, this result is achieved by simply removing cap- '14 (if the latter is utilized). Likewise if casing 10 extends below disc or washer 15 in the manner shown in the drawings, a relatively thin wrench or pair of long nose pliers may be inserted into the base end of the casing to grip the strip. Of course, when the casing terminates adjacent the disc or cup 15, then any suitable tool may be employed.

In any event, by gripping casing 10 and exerting a bending force on the tail piece 16 the latter may be rocked with respect to the casing. Having in mind the brazing or similar connecting expedient which has been resorted to, that adjustment of the parts will not open the casing so that foreign material may enter same. Whatever position the tail piece or strip 16 is shifted to will be substantially maintained by it. This is due to the fact that the disc or washer 15 will under the conditions of adjustment become slightly distorted and will not tend to return to its initial condition. With the rocking of the tail piece strut 17 will, of cou-rse, have been swung. According to the amount of adjustment, arms 25, spring 23 and bar '24 will have been similarly rocked or shifted.

The cup 15 serving as the point of fulcrum, the shift of the parts adjacent their upper ends will have been relatively large. In any event, a desired range adjustment will be effected. Accordingly, it is feasible to utilize a tubular 3 casing which may terminate adjacent or below the disc or washer at any desired point. That casing will have been formed of standard stock. It will not have been necessary to spin the lower end of the casing tubefdown to a smaller diameter. Also, it will not be necessary to atten the end of the tube. Thereby, manufacturingA expenses will be materially reduced. At the same time and as shown in the Broekhuysen patent, if it is not desired to employ a wrench or pliers for the purpose of adjustment, any suitable shifting expedient as in Figs. 1, 2 and 14'to 18 lof that patent may be resorted to. Y,

Thus, among others, the several objects ofthe invention as specifically aforenoted are achieved. It is obvious that various arrangements of operating mechanisms may be included as part of the present assembly over those specifically shown in the drawings; In this connection it is apparent that the several assemblies as shown in the Iafore-mentioned Broekhuysen patent, aswell as in other thermostatic mechanisms, might be included within the scope of the present teachings and that numerous other ychanges in construction and rearrangements of the parts may be resorted to without departing from the scope of the present invention.

What is claimed is: Y

1. A thermostat including in combination a hermetically sealed casing having a bore of uniform diameter, a. distortable Washer connected to one end of said casing, a strut disposed within said casing and having a coe cient of expansion different from that of the latter, a pair of relatively movable electrical contacts also disposed within said casing, means connected to said strut to shift said contacts into and out of engagement with each other, one end of said strut being rigidly connected to said casing and an opposite end of said strut .being connected to said washer, the latter and said strut cooperating together for adjustment of the operating point of the thermostat Without breaking the hermetic seal.

2. A thermostat including in combination a hermetically sealed casing having a bore of uniform diameter, a

strut disposed within said casing and having a coeicient of expansion different from that of the latter, a pair of relatively movable electrical contacts also disposed within the casing, means connected to said strut to shift said contacts into and out of engagement with each other, one end of said strut being connected to a side wall adjacent one end of said casing, a distortable washer sealably secured to the opposite end of said casing and an extension of said strut secured to and projecting beyond said washer, said strut and said washer cooperating for adjustment of the operating point of the thermostat without breaking the hermetic seal. Y

3. A thermostat including in combination a hermetically sealed casing, a strut disposed within said casing, said strut having a coeicient of expansion different from that of the casing and comprising two end portions and a center portion, said center portion being provided with a zone of tlexure, a pair of relatively Ymovable electrical contacts also disposed Within said casing, means connected tosaid strutto shift saidfcontacts into and out of engagement with each other, a distortable washer sealably secured to an end of the casing, an end of said strut rigidly connected to the inside of said casing and the opposite end of said strut secured to and projecting beyond said washer, said washer and said strut cooperating for the adjustment of thev thermostat without breaking the hermetic seal.

4. A thermostat as in claim 3 wherein said means connected to said strut to shift said contacts into and out of engagement with each other being connected to said strut at the zone of llexureV l References Cited in the tile of this patent UNITED STATES PATENTS 2,496,229 Parkhurst Ian. 31, 1950 2,550,188 Darling Apr. 24, 1951 2,664,483 Broekhuysen Dec. 29, 1953 .2,705,745 Matthysse et al Apr. 5, 1955

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