US2296435A

US2296435A - Pressure responsive element of the wafer type

Info

Publication number: US2296435A
Application number: US185147A
Authority: US
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1938-01-15
Filing date: 1938-01-15
Publication date: 1942-09-22
Anticipated expiration: 1959-09-22

Description

Sept. 22, GlARD PRESSURE RESPONSIVE ELEMENTS OF THE WAFER TYPE Filed Jan. 15, 19:58

Patented Sept. 22, 1942 2,296,435 rnsssuas nssg ggsrvi: ELEMENT or run EBTYP Eugene Armand Giard, deceased, late of Milwaukee, Win, by Beatrice L. Giard, special administratrix, Milwaukee, Wis., assignor to Cutler- Bammer, Inc., Milwaukee, Wis., a corporation of Delaware Application January 15, 1938, Serial No. 185,147

8 Claims.

This invention relates to pressure responsive elements of the wafer type and to a method of making the same.

The application of C. W. Kuhn et al., Serial No. 157,988, filed August '7, 1937 now Patent No. 2,245,691, dated June 17, 1941, discloses an operating mechanism for refrigerator controllers including a gas containing element of the wafer type. Such element meets various requirements, as for example the same is of small diameter, sensitive, capable of movement through a relatively wide range, capable of supplying a substantial operating force, capable of functioning smoothly and with uniformity, and able to withstand many operations daily over a period of many years. To meet these requirements the wafer element has various novel structural features, and this invention involves certain of these features.

The accompanying drawing illustrates an embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification without departing from the spirit and scope of the appended claims.

In the drawing:

Figure 1 is an enlarged side elevational view of a wafer element embodying the invention, a cup-shaped support associated with the element being shown in section;

Figs. 2 and 3 are enlarged plan views of solder rings which are employed in making the bellows shown in Fig. 1;

Fig. 4 is an enlarged sectional view illustrating the parts of the wafer element assembled for soldering, and 1 Fig. 5 is a greatly enlarged sectional view of a portion of the wafer element.

Referring to Fig. 1 the same illustrates a wafer element I having a pipe extension 2 which terminates in a gas-filled bulb portion 3 preferably of the spiral form illustrated, although it may assume other forms. As shown the wafer element also has a cup-shaped support 4 fixed thereto.

The wafer element l in a broad sense is of a well known form, but the same differs essentially from expansible-wafers heretofore employed in devices of various types. It is designed for use in connection with refrigerator control devices and in order to meet the various requirements hereinbefore noted the same must be formed of very thin sheet metal parts and provided with joints which are exceedingly strong and durable.

imperative to join the parts of the wafer element with silver solder and the problem is then presented by applying sufflcient heat to melt such solder without warping or otherwise impairing the thin sheet metal parts. In accordance with the present invention the wafer element is provided with oppositely disposed circular

cupshaped elements

5 and 6 which are formed of partially annealed fine grain beryllium copper sheet of a thickness of about .005 inch. It has been found that such material is capable of withstanding the heat required for hard soldering without becoming warped or otherwiseimpaired, and is also desirable for other reasons.

Cup element 5 is formed to provide an outwardly extending flange 9 which is disposed at right angles to the axis of said element and said element is also formed to provide a circular flange l0 which surrounds said former flange and is disposed at right angles with respect thereto. Cup element 6 has an outwardly extending flange II which is disposed at right angles to the axis thereof and said flange is of slightly less diameter than the inside diameter of flange l0 on element 5.

Cup element 6 is also provided with a center opening for receiving a hollow cylindrical nipple I2 formed of drawn brass tubing and having an opening in one end thereof for receiving the tube 2 and an outwardly extending circular flange l3 on the opposite end thereof. Nipple I2 is slightly tapered to facilitate insertion thereof into the opening in cup member 6 and the same is provided with a surrounding groove I4 adjacent flange l3 for receiving the inner edge of said cup element. Flange I3 is shaped to provide an annular shoulder l5 and the diameter of nipple I2 is such that when cup element 6 is sprung over said shoulder as shown in Fig. 5 the inner edge of said element is driven into the groove l4.

Referring now to Figs. 2 and 3 the same illustrate soldering rings l6 and H, the former being employed for soldering the joint between

cup elements

5 and 6, and the latter being employed for soldering the joint between cup element 6 g and nipple l2. Solder ring it is of such diameter It has been found that it is very desirable if not 5 as to fit snugly within flange III on cup element 5 and the same consists of-two parts a and 12, each of which is weakened at a plurality of sp ced points by notches l8. As is apparent the notches I8 render the solder ring l6 relatively flexible at a plurality of points to facilitate engagement of said ring throughout its entire circumference with the inner surface of flange l0. Also during soldering the weakened portions of ring I6 adjacent the notches l8 melt prior to the other portions to thereby prevent warping of said ring.

Solder ring I1 is of such diameterv as to sn y- 5 so that flange rests upon flange 9 and the parts are then sprayed with a suitable liquid flux. Solder rings I6 and ll a renext placed in position, care being taken to insure engagement 1 of ring "5 with flange H on element 6 and engagement of ring I! with the inner margin of said element. The parts are again sprayed with the liquid flux and then baked to dry the flux.

The joints of the wafer element are soldered simultaneously, in a soldering device, which does.

not enter into this invention. The soldering device employed is provided with a pair of horizontally arranged ring shaped heater elements l9 and 29 illustrated in dotted lines in Fig. 4. The wafer assembly is inserted within the soldering device with its nipple I2 extending upwardly and during soldering the assembly is maintained with its axis in a vertical position. Upon insertion of the wafer assembly within the soldering device, heater element l9 closely surrounds flange l0 and heater element 20 closely surrounds nipple I2 and is located adjacent the soldenring II.

Under the action of heater elements l9 and 20 the solder rings 16 and H are melted simultaneously and within a relatively short interval without undue'heating of the cupped portions I2 and said casing isv secured to said nipple by striking the metal of the sleeve inwardly at a of

wafer elements

5 and 6. The solder of ring I5 adheres to the inner surface of flange"! and is also drawn inwardly'by capillary attraction between the flanges 9 and II. As is apparent from Fig. 5 the flanges 9 and I I are thus connected bya continuous ring of hard solder to provide a very strong and durable joint with but slight increase in the diameter of the wafer as compared with the diameter of the cup portionand'without stiffening of either cup portion by a flow of solder inwardly beyond the flanges 9 and H. Solder ring I! when melted adheres to nipple l2 and to the inner marginal portion'of, cup element 6 to form a continuous ring of solder between the inner edge of said, element and nipple I 2.

After soldering the wafer element is heat treated to harden the beryllium

bronze cup elements

5 and 6. The same is then thoroughly cleaned and tube 2 is soldered to nipple l2, a small ring of hard'solder such as silver being used for this purpose. The bellows assembly is then evacuated and filled under pressure with a suitable fluid, as for example methyl chloride, and after filling the outer end of tube 3 is sealed and the entire unit is plated for protection against corrosion.

The joint between cup element Sand nipple l2 would not be durable if left unprotected, and for Thus flexing of the 'cup' 'elementfi is limited to points spaced from the number of points circumferentially thereof as shown at 24 in Fig. 1.

. What is claimed as new and desired to be secured by Letters Patent is:

1. An expansible wafer comprising two circular cupped elements of thin sheet metal having peripherally thereof a continuous soldered joint lying in a plane from which the cup portions of said elements project in opposite directions, one of said elements having its marginal portion formed to provide a radially extending flat annulusland a ring upstanding from such annulus and the other element having. its marginal portion formedto provide a radially extending 'flat annulus to fit within said upstanding ring of the former element, said soldered joint comprising said marginal portions of said elements and solder bonding together the inner surfaces of the annuli of said elements, the wafer exterior surfaces contiguous to said annuli being free of solder and said ring being permanently upstand- 2. An expansible wafer comprising two circular'cupped elements of thin sheet metal having peripherally thereof a continuous soldered joint lying in a plane from which the cup portions of said elements project in opposite directions, one of said elements having its marginal portion formed to provide a radially extending flat annulu's. and a ring upstanding from such annulus and the other element having its marginal portion formed ,to provide a radially extending flat annulus to fit within said upstanding ring of the former element, said soldered joint comprising said marginal portions of said elements and solder bonding together the inner surfaces of the annuli of said elements, and also bonding to said inner surface of the ring the outer surface of the annulus inserted into said ring, the wafer exterior surfaces contiguous to said annuli being free of solder and said ring being permanently upstanding.

3. An expansible wafer comprising two circular cupped elements of thin sheet metal having peripherally thereof a continuous soldered joint lying in a plane from which the cup portions of solder joint and the clamping parts are curved to insure against sharp curvature of said ele- 4. A gas containing wafer comprising two cir-- said elements project in opposite directions, one of said elements having its marginal portion formed to provide a radially extending flat annuannulus of the second mentioned element to the, ring of the other element, the wafer exterior surfaces contiguous to said annuli being free of solder and said ring being permanently upstandcular cupped elements of thin sheet metal having peripherally thereof a continuous soldered joint lying in a plane from which the cupped portions of said elements project in opposite directions, one of said elements having its marginal portion formed to provide a radially extending flat annulus and a ring upstanding from such annulus and the other element having its marginal portionformed to provide a-radially extending fiat annulus to fit within said ringof the former element, said soldered joint comprising said marginal portions of said elements and a ring of solder bonding the exposed peripheral edge of the annulus of the second mentioned elementto the ring of the other element, said soldered ring also extending between the inner surfaces of the annuli of said elements, the spacing of said surfaces being such as to afford flow of the solder by capillarity between said annuli, the wafer exterior surfaces contiguous to said annuli being free of solder and said ring being permanentlyupstanding.

5. A gas containing wafer comprising two circular cupped elements of thin sheet metal having peripherally thereof a continuous soldered joint lying in a plane from which the cupped portions of said elements project in opposite directions, one of said elements having its marginal portion formed to provide a radially extending flat annulus and a ring upstanding from such annulus and projecting beyond said soldered joint and the other element having its marginal portion formed to provide a radially extending flat annulus to fit within said ring of the former element, said soldered joint comprising said marginal portions of said elements and a ring of solder bonding the exposed peripheral edge of the annulus of the second mentioned element to the ring of the other element, said soldered ring also extending between the inner surfaces of the annuli of said elements, the spacing of said sur-.

faces being such as to afford flow of the solder by capillarity between said annuli, and said annuli being of a breadth suflicient to prevent flow of solder onto the cupped portions of said elements.

6. An expansible wafer comprising a cupped disk and a cupped annulus, both of thin sheet metal and having peripherally thereof a continuous soldered joint, and a nipple with which said annulus has a continuous soldered joint,

said nipple having a cylindrical portion termi-' nating in an annular end flange forming an abutment for said annulus which permits the central portion of said annulus to be sprung inwardly along said nipple and said cylindrical portio'nof said nipple having adjacent its juncture with said flange an encircling groove receiving the edge of the inner marginal portion of said annulus when said annulus is sprung inwardly along said nipple, the solder of said joint between said nipple and annulus bonding said elements externally and extending into said groove.

7. An expansible wafer comprising a cupped disk and a cupped annulus, both of thin sheet metal and having peripherally thereof a continuous soldered joint, a nipple for said annulus having a cylindrical portion terminating in an annular end flange forming an abutment for said annulus which permits the central portion of said annulus to be sprung inwardly along said nipple, said cylindrical portion of said nipple having adjacent its juncture with said flange an encircling groove into which the edge of the inner marginal portion of said annulus is driven when said annulus is sprung inwardly along said nipple, said inwardly sprung portion of said annulus forming with said nipple an external .circular groove, and a continuous solder ring formed in said groove to join said annulus and nipple,

8. An expansible wafer comprising a cupped disk and a cupped annulus, both of th n sheet metal and having peripherally thereof a continuous soldered joint, a nipple for said annulus having a cylindrical portion terminating in an annular end flange forming an abutment for said annulus which permits the central portion of said annulus to be sprung inwardly along said nipple, said cylindrical portion of said nipple having adjacent its juncture with said flange an encircling groove into which the edge of the inner marginal portion of said annulus is driven when said annulus is sprung inwardly along said nipple, said inwardly sprung portion of said annulus forming with said nipple an external cir-