Subassembly for a pressure switch

• US 5,252,792 A
• Filed: 09/06/1991
• Issued: 10/12/1993
• Est. Priority Date: 05/12/1989
• Status: Expired due to Term

• Current Assignee: Ranco Incorporated of Delaware (Schneider Electric SE)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Joyce, Ronald S.
• Primary Examiner(s): Tolin, Gerald P.
• Application Number:
  US07/758,520
• Time in Patent Office: 767 Days
• Field of Search: 307/118, 73/717, 73/723, 340/626, 200/250, 200/251, 200/286, 200/302.1, 200/83 R, 200/83 P, 200/83 S, 200/83 SA, 200/83 WM, 200/402, 200/416, 200/445, 200/450, 200/542, 200/573, 200/574, 337/319, 337/320
• US Class Current: 200/83.00P
• CPC Class Codes: H01H 35/2614 by varying the bias on the pressure sensitive element
• CPC Class Codes: H01H 35/2635 by adjustment of a motion transmitting system
• CPC Class Codes: H01H 35/34 actuated by diaphragm

Abstract

A pressure switch assembly has a preassembled spring capsule assembled onto a deck structure with a snap switch thereon to form a subassembly which is snap-locked into the cup-shaped housing. A rotary cam drum is provided in the housing with an external shaft for changing the setting. An adjustment lever has a bifurcated portion nested about the inner periphery of the cam drum and a threaded external adjustment is provided for moving the lever position against the spring capsule for calibration. The pressure switch is completely assembled from one side of the housing.

Claims

1. In a pressure switch of the type having a first cupped housing shell (12) with a fluid pressure sensing chamber (30) and a pressure responsive diaphragm (18) disposed therein and movable in response to changes in chamber pressure for actuating a switch, a sub-assembly removable from said first shell comprising:

(a) a support deck structure (68) having an aperture therethrough (100) and having a snap-acting switch (70) mounted on one side thereof, said switch having an actuator member (102) extending over said aperture; and

,

(b) a spring capsule (66) removably assembled to said support deck structure including a preload spring (82) and a spring retaining cup member (88) registered against one end of said spring with the opposite end of said spring registered against a first portion (76) of an operating rod (28), said rod including other portions (78) thereof operative to limit movement of said rod in one direction with respect to said retaining cup member, said capsule being disposed on said deck on the side opposite said switch with said rod extending through said aperture and in registration with said switch actuator member, wherein said spring retaining cup member (88) is guided for sliding movement on said deck structure and retained thereon to preload said spring, said support deck with said spring capsule mounted thereon comprising a unit adapted for sliding assembly in said pressure switch first housing shell.

2. The subassembly defined in claim 1, wherein said support deck has a generally circular configuration and includes a generally cylindrical portion extending therefrom with said spring capsule nested therein.

3. The sub-assembly defined in claim 1, wherein said spring capsule includes a second spring (86) surrounding said preload spring, said second spring having one end registered against said spring retaining cup member (88) and the other end registered against an annular retaining flange (84) with said preload spring (82) and said rod portions (76) passing through said flange, wherein said rod has said other portions (78) thereof in a lost motion connection to said spring retaining cup member.

4. The sub-assembly defined in claim 1, wherein:

(a) said spring capsule includes a second coiled spring (86) surrounding said preload spring, with one end of said second spring registered against said spring retaining cup member (88) and the other end registered against an annular retaining flange (84) having said rod member (28) passing therethrough; and

,

(b) said annular retaining flange (84) registers against said portions (76) of said rod in the unassembled state to retain said capsule as a unit.

5. A pressure switch assembly comprising:

(a) a cup-shaped housing shell (12);

(b) a support deck sub-assembly (64) slidably received in said shell including a snap-acting switch (70) secured thereto and a removable preload spring capsule (66); and

,

(c) said housing shell having a plurality of spring tabs (162) formed integrally thereon for retaining said deck sub-assembly therein, said tabs resiliently deflectable in a radial direction, said shell having cut-outs (158) in the closed end of said cup shape, wherein said tabs are formed by pulling of forming molds for said tabs in an axial direction through said cut-outs.