Features of a condition responsive switch

• US 4,581,509 A
• Filed: 07/20/1984
• Issued: 04/08/1986
• Est. Priority Date: 07/20/1984
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sanford, Carlton E., Lesser, Paul A.
• Primary Examiner(s): Tolin, G. P.
• Application Number:
  US06/633,158
• Time in Patent Office: 627 Days
• Field of Search: 337/343, 200/83 R, 200/83 J, 200/83 L, 200/83 P, 200/83 W, 200/302, 200/81 R, 200/81.9 R
• US Class Current: 200/83.00P
• CPC Class Codes: H01H 35/34 actuated by diaphragm

Abstract

A thermal or pressure responsive switch has a base mounting a set of electrical contacts. A metallic snap acting disc support, placed on the base is provided with a bore which receives a pin to transfer motion from a disc mounted on the support to the set of electrical contacts upon snapping of the disc.

A first embodiment has a pressure converter received on the disc support. The peripheral edge of the snap acting disc is received on a seat formed in the converter with an annular reaction ridge formed on the support.

A second embodiment has a pressure converter with the peripheral edge of the snap acting disc received on a seat formed in the disc support and an annular force ridge on the converter is adapted to contact the upper surface of the disc. In either embodiment a layer of low friction plastic can be placed on both faces of the disc.

A third embodiment has a flat metallic disc support with a recessed portion for receiving the disc and a continuous stop surface.

In all embodiments a cup shaped shell has a gasket received in a channel formed in a top end wall of the shell with the outer wall portion of the shell crimped over to compress the gasket and provide a gas tight seal.

The top end wall of the shell can be formed with a portion displaced from the wall to serve as an automatic valve deflator which can be used with any of the embodiments.

Claims

1. A condition responsive switch having first and second electrical contacts mounted on a base member, the contacts movable relative to one another into and out of circuit engagement, the base provided with an upstanding annular wall with a top wall surface and a lower wall surface, a metallic disc support and motion transfer pin guide member having a bottom and a top received on the base, a condition responsive disc received on the support and guide member, the disc movable between convex and concave configurations upon the occurrence of selected conditions, a bore extending through the support and guide member from the top to the bottom, a diaphragm received on top of the support member and extending over the disk, a metallic cup shaped shell having a closed end wall with an annular gasket receiving channel formed in the outer peripheral portion of the closed end wall aligned with the outer periphery of the diaphragm, the cup having a downwardly depending wall with a free distal end portion, an annular gasket received in the channel, the cup shaped shell received over the support and guide member with the free distal end portion of the depending wall crimped onto the lower wall surface of the base to compress the gasket against the diaphragm to obtain an improved gas tight seal, the metallic disc support and motion transfer pin guide member being generally flat and having a curved annular recess formed in the top adjacent the outer periphery of said member whereby the diaphragm is forced into the annular recess by flexing the gasket, a motion transfer member slidingly received in the bore of the support and guide member and adapted to transfer motion from the condition responsive disc to the electrical contact members to cause relative motion of the contact members, and a fluid pressure receiving orifice formed in the closed end of the cup shaped shell.

2. A condition responsive switch according to claim 1 in which the end wall of the shell is formed with a stop surface adjacent the gasket receiving channel to limit the amount that the gasket can be compressed.

3. A condition responsive switch according to claim 1 in which a continuous annular overtravel stop surface is formed on the disc support and motion transfer pin guide member and so disposed in the path of the disk to prevent overtravel and overstressing of the disc.

4. A condition responsive switch having first and second electrical contacts mounted on a base member, the contacts movable relative to one another into and out of circuit engagement, the base provided with an upstanding annular wall with a top wall surface and a lower wall surface, a disc support and motion transfer pin guide member having a bottom and a top received on the base, a condition condition responsive disc received on the support and guide member, the disc movable between convex and concave configurations upon the occurrence of selected conditions, a bore extending through the support and guide member from the top to the bottom, a diaphragm received on top of the support member and extending over the disk, a metallic cup shaped shell having a closed end wall with an annular gasket receiving channel formed in the outer peripheral portion of the closed end wall aligned with the outer periphery of the diaphragm, the cup having a downwardly depending wall with a free distal end portion, an annular gasket received in the channel, the cup shaped shell received over the support and guide member with spaced portions of the free distal end portion of the depending wall of the shell crimped onto the lower wall surface of the base to compress the gasket against the diaphragm to obtain an improved gas tight seal,

an annular groove formed in the outer portion of the upstanding wall of the base and a gasket disposed in the annular groove to provide a moisture seal,

a motion transfer member slidingly received in the bore of the support and guide member and adapted to transfer motion from the condition responsive disc to the electrical contact members to cause relative motion of the contact members, and a fluid pressure receiving orifice formed in the closed end of the cup shaped shell.

5. A condition responsive switch according to claim 4 in which a continuous annular overtravel stop surface is formed on the disc support and motion transfer pin guide member and so disposed in the path of the disk to prevent overtravel and overstressing of the disc.

6. A condition responsive switch according to claim 4 in which the end wall of the shell is formed with a stop surface adjacent the gasket receiving channel to limit the amount that the gasket can be compressed.

7. A condition responsive switch having first and second electrical contacts mounted on a base member, the contacts movable relative to one another into and out of circuit engagement, the base provided with an upstanding annular wall with a top wall surface and a lower wall surface, a disc support and motion transfer pin guide member having a bottom and a top received on the base, a condition responsive disc received on the support and guide member, the disc movable between convex and concave configurations upon the occurrence of selected conditions, a bore extending through the support and guide member from the top to the bottom, a diaphragm receied on top of the support member and extending over the disk, a metallic cup shaped shell having a closed end wall with an annular gasket receiving channel formed in the outer peripheral portion of the closed end wall aligned with the outer periphery of the diaphragm, the cup having a downwardly depending wall with a free distal end portion, an annular gasket received in the channel, the cup shaped shell received over the support and guide member with the free distal end portion of the depending wall crimped onto the lower wall surface of the base to compress the gasket against the diaphragm to obtain an improved gas tight seal, a motion transfer member slidingly received in the bore of the support and guide member and adapted to transfer motion from the condition responsive disc to the electrical contact members to cause relative motion of the contact members, a fluid pressure receiving orifice formed in the closed end of the cup shaped shell and a port fitting having an axially extending bore sealingly attached to the closed end wall of the cup shaped member circumscribing the fluid pressure receiving orifice, the fluid pressure receiving orifice being formed by a pair of slits extending through the closed end of the cup shaped shell with the wall between the slits displaced a selected distance into the axially extending bore to serve as an automatic deflator element integrally formed with the closed end wall of the cup shaped shell.

8. A condition responsive switch according to claim 7 in which a continuous annular overtravel stop surface is formed on the disc support and motion transfer pin guide member and so disposed in the path of the disk to prevent overtravel and overstressing of the disc.

9. A condition responsive switch according to claim 7 in which the end wall of the shell is formed with a stop surface adjacent the gasket receiving channel to limit the amount that the gasket can be compressed.