Adjustment mechanism for pressure switch

• US 5,393,945 A
• Filed: 06/20/1994
• Issued: 02/28/1995
• Est. Priority Date: 01/27/1992
• Status: Expired due to Term

• Current Assignee: Ranco Incorporated of Delaware (Schneider Electric SE)
• Original Assignee: Eaton Corp. (Wisconsin) (Eaton Corporation PLC.)
• Inventors: Obermann, George, Joyce, Ronald S.
• Primary Examiner(s): Pellinen, A. D.
• Assistant Examiner(s): Friedhofer, Michael A.
• Application Number:
  US08/263,112
• Time in Patent Office: 253 Days
• Field of Search: 200/83 R, 200/83 A, 200/83 Q, 200/83 W, 200/83 S, 200/83 Z, 200/83 WM, 200/83 SA
• US Class Current: 200/81.00R
• CPC Class Codes: H01H 35/2614 by varying the bias on the pressure sensitive element

Abstract

A sliding type adjustment mechanism for changing settings of a diaphragm type pressure switch adjusted by moving an external lever to move a plunger for changing the preload on the diaphragm. An external metal mounting bracket has a pair of spaced parallel slots which serve as ways. A plastic slider with a cam surface engaging the lever has a pair of lugs, each of which engages one of the slots for guiding the slider on the bracket. The slider has an integrally formed spring tab providing friction against the bracket to hold the slider in a selected position. A recess in the bracket relieves the tab friction at the limit of the slider travel to allow the lever to bias a steep-ramp portion of the cam surface to move the slider to an initial position.

Claims

1. In a pressure switch having an adjustment member movable externally with respect to the pressure switch housing for adjusting actuation settings the improvement comprising:

(a) bracket means attached to said pressure switch housing, said bracket means defining a pair of spaced parallel guide ways and detent means thereon;

(b) slider means disposed for sliding movement on said ways, said slider means defining an adjustment cam surface operable to contact said adjustment member, and defining integrally therewith (i) lug means engaging each of said ways and slidably retaining said slider means on said bracket means, (ii) spring means operable to maintain desired minimum friction forces resisting said movement of said slider means and said bracket means, said spring means further operable to engage said detent means at a predetermined position of said slider means for releasing said friction forces.

2. The improvement defined in claim 1, wherein said bracket means is formed of metallic material and said slider means comprises a unitary member formed of non-metallic material.

3. The improvement defined in claim 1, wherein said ways comprise a pair of elongated slots formed in said bracket means.

4. The improvement defined in claim 1, wherein said guide ways comprises a pair of elongated slots having enlarged portions formed at a selected location thereon to permit free passage of said lug means therethrough for removal and assembly of said slider means on said bracket means.