US3747039A

US3747039A - Thermostat and method of making same

Info

Publication number: US3747039A
Application number: US00271293A
Authority: US
Inventors: C Hire
Original assignee: Fasco Industries Inc
Current assignee: Fasco Controls Corp
Priority date: 1972-07-13
Filing date: 1972-07-13
Publication date: 1973-07-17
Anticipated expiration: 1990-07-17
Also published as: CA979957A

Abstract

A cup-shaped metal can containing a thermostatic switch unit is mounted in an opening in the bottom of a cup-shaped plastic jacket, and has two terminals which project into the jacket and which have lead wires connected thereto. The wires extend out through notched openings in the side of the jacket, and are retained in those openings by a ring member which seats on the open end of the jacket and which has a diametral web at opposite sides of which the lead wires are disposed. The can has a flared open end; and the can and ring member are secured in place by epoxy flowed into the open end of the can and around its flared end and into the jacket to a point beneath the notched openings.

Description

United States Patent [191 Hire [ July 17, 1973 [75] Inventor: Charles John Hire, Rochester, N.Y.

[73] Assignee: Fasco Industries, Inc., Rochester,

[22] Filed: July 13, 1972 [21] App]. No.: 271,293

3,636,622 l/l972 Schmitt 29/622 Primary Examiner-Harold Broome Attorney-B. Edward Shlesinger et al.

[5 7] ABSTRACT A cup-shaped metal can containing a thermostatic switch unit is mounted in an opening in the bottom of a cup-shaped plastic jacket, and has two terminals which project into the jacket and which have lead wires connected thereto. The wires extend out through notched openings in the side of the jacket, and are retained in those openings by a ring member which seats on the open end of the jacket and which has a diametral web at opposite sides of which the lead wires are disposed. The can has a flared open end; and the can and ring member are secured in place by epoxy flowed into the open end of the can and around its flared end and into the jacket to a point beneath the notched openmgs.

6 Claims, 3 Drawing Figures men-ream 1 1 w FIG. 2

Hes

THERMOSTAT AND METHOD OF MAKING SAME This invention relates to thermostats, and more particularly to thermostats intended for use in high moisture locations like refrigerators.

Heretofore one of the major problems encountered with thermostats employed in high moisture ambients is the probability that sooner or later moisture will seep into the interior of the thermostat, and short out the switch contacts.

Usually the lead wires from the switch contacts of the thermostatic unit are brought out of one end of the thermostat casing. In some instances, however, the lead .wires from the switchcontacts are brought out of the side of the thermostat housing. Heretofore this has required that, during assembly of the thermostat, the lead wires be carefully threaded or fished out through holes in the side of the casing. Assembly in this manner has proved to be unnecessarily time consuming and expensive.

It is an object of this invention to provide an improved thermostat which has sections thereof carefully assembled to provide a housing that is substantially waterproof and moisture impervious.

Another object of the invention is to provide a thermostat having a high dielectric path from the thermostatic switch unit itself and its lead wires to external surfaces.

Another object of this invention is to provide an improved thermostat in which the lead wires for its switch contacts can readily be guided to the exterior of the thermostat during its assembly, minimizing assembly time and consequently the cost of the thermostat.

Still another object of this invention is to provide an improved method of manufacturing thermostats of the type described through which high dielectric, waterproof connections can' be made between the thermostatic switch unit itself, its lead wires and cooperating sections of the thermostat housing.

Other objects of the thermostat will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawing.

In the drawing:

FIG. 1 is a fragmentary sectional view, taken along the line 11 in FIG. 2 lookingin the directionof the' arrows, and showing a thermostat constructed according to one embodiment of this invention;

F IG. 2 is a fragmentary plan view of this thermostat, a portion of the epoxy'filling in the housing of the thermostat being cut away for purposes of illustration;

FIG. 3 is an elevational view of the thermostat but with its two lead wires cut away and shown in section.

Referring now to the drawing by numerals of reference, denotes generally a thermostat comprising a cup-shaped metal can or casing 12 having an outwardly flared lip 11 around its open end and containing a rigid, generally disc-shaped, dielectric base member 13, which is press-fit or otherwise secured in the housing coaxially thereof. In its outer end base member 13 has a circular recess 14, which is bounded by an annular skirt portion 15 that projects from the inner side of the base toward the closed end of can 12. Recess 14 surrounds a cone shaped projection 16 that protrudes from base 13 centrally thereof.

Secured by rivets l8 and 19 on the inner surface of base 13 are two, right-angular

electric terminals

20 and 21. Secured at one end beneath the head of the rivet 18 and extending diametrally across recess 14 is a flexible, metal switch arm 23. Intermediate its ends arm 23 is bent as at 24 to overlie the projection 16; and at its free end this arm carries a metal contact 25 that overlies the outer end of rivet 19. The bend 24 at the center of arm 23 registers approximately with the center of a temperature-responsive, bimetallic disc 27, which is mounted between skirt 15 and the closed end of can 12.

To assemble the thermostat, wire leads W1 and W2 are spot-welded or otherwise fixed to the upright legs of

terminals

20 and 21, as illustrated in FIG. 2. The can 12 is then inserted, closed-end first, through a central opening 31 formed in the bottom of a plastic, generally cup-shaped jacket 32, which is slightly larger in diameter than can 12. The two wires W1 and W2 are then led laterally outwardly through spaced notches or recesses 33 and 34 (FIGS. 2 and 3), which are formed in the upper, marginal edge of the jacket 32 at one side thereof. An annular, dielectric member 36, which has a narrow, diametric web 37 suspended therefrom by integral straps 38, is then positioned over the upper end of jacket 32 so that the wires W1 and W2 will be disposed at opposite sides of the web 37. A flange 41 on the annular member 36 seats on the outer end of jacket 32. Projecting from the inner side of web 37 is a cylindrical post or stem 39, which has on its lower end an enlarged-diameter head 40 that helps to anchor the cover 36 on jacket 32 as noted hereinafter. Web 37 also has a cylindrical post or stem 42 projecting from its opposite side coaxially through the center of the jacket 36 and slightly beyond-the open end thereof.

When the can 12, jacket 32 and cover 36 have been thus assembled, the lip portion 11 on the can will be spaced slightly above (FlG. 2), or inwardly from, the closed end of jacket 32.

An epoxy resin is then flowed into jacket 32 and the upper end of can '12until the jacket is filled to the level L, which is just below the bottoms or inner ends of the grooves 33 and 34. The epoxy flows into the space between the lip 11 and the jacket 32, and also encircles the web 37 and post 39. Also, of course, the projecting ends of

terminals

20 and 21 and the portions of the wires W1 and W2 fastened thereto are embedded in the epoxy.

When the epoxy resin sets, then, can 12 and ring member 36 will be rigidly and sealingly fastened in jacket 32. Moreover, because of the space, between lip 11 of can 12 and jacket 32, both the inner and outer surfaces of the can in the area of its lip 11 are completely surrounded by, or embedded in the resin, so that moisture cannot possibly leak through the jacket 32 and into the open end of the can. Moreover, since open slots or grooves 33 and 34 are employed to accommodate the wires W1 and W2, rather than radial openings in the annular wall ofjacket 32, assembly of the unit is greatly simplified, since the operator does not have to waste time trying to fish or thread the wires W1 through any openings. Further, the headed stem 39 helps to anchor the ring 36 securely over the open end of jacket 32 and the laterally projecting wires W1 and W2.

While two, spaced notches 33 and 34 have been formed in the open end of jacket 32 to accommodate the wires W1 and W2, it will be apparent that a single notch could be employed for this purpose, if desired. Moreover, it will be apparent that the angular relationship of web 37 to the wires W1 and W2 is a matter of choice; and that it is not absolutely necessary that these wires pass through the jacket sidewall at opposite sides of web 37.

While the invention has been described, then, in connection with a specific embodiment thereof, it will be understoodvthat it is capable of further modification, and that this application is intended to cover any modifications of the invention that come within the disclosure or the limits of the appended claims.

Having thus described my invention, what I claim is:

l. The method of manufacturing a thermostat, comprising mounting a cup-shaped casing containing a temperature-responsive switch and having a flared open end and having two lead wires secured to a pair of switch terminals which project from the open end of said casing in an opening in the closed end of a generally cup-shaped, plastic jacket,

guiding said wires laterally outwardly through a pair of notches formed in the marginal wall of said jacket at its open end,

positioning an annular member over the open end of said jacket to overlie said notches and the wires extending therethrough, said member having an integral, diametrally extending web, and flowing an epoxy resin into said jacket to a level above said web, and beneath said notches, thereby to secure said member and said casing sealingly in said jacket.

2. A thermostat, comprising a housing containing a temperature-responsive switch having a pair of wire leads that project from one end of the housing,

a generally cup-shaped, dielectric jacket having an opening in its base,

means securing said housing in said opening with said one end of the housing projecting into said jacket, and i an annular member having an integral, diametrally extending web secured over the open end of said jacket with said web extending diametrally of said jacket and with said wire leads projecting through a pair of openings in said jacket at opposite sides of said web and beneath said annular member,

said securing means comprising a solid, dielectric filler material filling the interior of said jacket to a level sufficient to surround said one end of said can and said web.

3. A thermostat as defined in claim 2, wherein said housing flares laterally outwardly at said one end thereof, and

the outwardly-flaring end of said housing is spaced axially inwardly from the base of said jacket.

4. A thermostat as defined in claim 3, having an inte-,

gral stem projecting from the underside of said web into said filler material and having on its lower end an enlarged-diameter head embedded in said filler material to help secure said annular member on said jacket.

5. A thermostat as defined in claim 2 wherein a pair of angularly spaced recesses are formed in the annular wall of said jacket at the open end thereof, and said wires extend, respectively, through the two recesses. 6. A thermostat comprising a cup-shaped casing containing a thermostatic switch unit and having an outwardly flared rim at its open end, and a pair of electric terminals disposed in its open end and connected to the switch unit, a cup-shaped dielectric jacket having an opening in its base in which said casing is mounted, the diameter of said opening being less than the diameter of said casing at said rim,

a ring member seated on the dielectric jacket and an epoxy filler filling in the open end of said casing and said jacket to a level above said web but below said notches to retain said casing and said ring member in said jacket.

Claims

1. The method of manufacturing a thermostat, comprising mounting a cup-shaped casing containing a temperature-responsive switch and having a flared open end and having two lead wires secured to a pair of switch terminals which project from the open end of said casing in an opening in the closed end of a generally cup-shaped, plastic jacket, guiding said wires laterally outwardly through a pair of notches formed in the marginal wall of said jacket at its open end, positioning an annular member over the open end of said jacket to overlie said notches and the wires extending therethrough, said member having an integral, diametrally extending web, and flowing an epoxy resin into said jacket to a level above said web, and beneath said notches, thereby to secure said member and said casing sealingly in said jacket.

2. A thermostat, comprising a housing containing a temperature-responsive switch having a pair of wire leads that project from one end of the housing, a generally cup-shaped, dielectric jacket having an opening in its base, means securing said housing in said opening with said one end of the housing projecting into said jacket, and an annular member having an integral, diametrally extending web secured over the open end of said jacket with said web extending diametrally of said jacket and with said wire leads projecting through a pair of openings in said jacket at opposite sides of said web and beneath said annular member, said securing means comprising a solid, dielectric filler material filling the interior of said jacket to a level sufficient to surround said one end of said can and said web.

3. A thermostat as defined in claim 2, wherein said housing flares laterally outwardly at said one end thereof, and the outwardly-flaring end of said housing is spaced axially inwardly from the base of said jacket.

4. A thermostat as defined in claim 3, having an integral stem projecting from the underside of said web into said filler material and having on its lower end an enlarged-diameter head embedded in said filler material to help secure said annular member on said jacket.

5. A thermostat as defined in claim 2 wherein a pair of angularly spaced recesses are formed in the annular wall of said jacket at the open end thereof, and said wires extend, respectively, through the two recesses.

6. A thermostat comprising a cup-shaped casing containing a thermostatic switch unit and having an outwardly flared rim at its open end, and a pair of electric terminals disposed in its open end and connected to the switch unit, a cup-shaped dielectric jacket having an opening in its base in which said casing is mounted, the diameter of said opening being less than the diameter of said casing at said rim, a ring member seated on the dielectric jacket and having an integral diametral web, and a pair of lead wires secured to said terminals, respectively, and disposed at opposite sides of said web and extending outwardly of said jacket through notches in the top of the side wall of the jacket, said ring member seating on said side wall over said notches to retain said lead wires in said notches, and an epoxy filler filling in the open end of said casing and said jacket to a level above said web but below said notches to retain said casing and said ring member in said jacket.