US 4,070,752 A · Method of making an electrical switch and chemically milled contacts

Abstract

A rotary electrical switch is provided of the type that includes a stator body of substantially cylindrical shape having a cylindrical opening coaxially disposed therein. The stator body includes a plurality of electrical contacts embedded in the stator body at circumferentially spaced positions therearound and extending radially inward from the cylindrical opening in the stator body and having a pair of parallel disposed planar contact surfaces, all of the contacts being disposed in a common plane orthogonal to the longitudinal axis of the cylindrical opening. A rotor body is rotatably disposed in the cylindrical opening and a contactor clip including a pair of contactors electrically and resiliently engaging both planar contact surfaces of respective ones of the contacts is constrained to rotate with the rotor body. Each of the electrical contacts includes a pair of wedge-shaped edges for easy entrance of the planar contact surfaces in between the pair of contactors as the rotor is rotated in either direction. The method includes the manufacturing of the electrical switch particularly the manufacture of the electrical contacts and the wedge-shaped surfaces thereon by chemical milling.

Claims8

Dependent claims

A method of producing an electrical switch component comprising the steps of:

(a) producing a pattern for fabricating a plurality of interconnected electrical contacts within a portion of a strip of metal;
(b) defining the pattern on a first side of the strip of metal by the application of an acid resistant coating thereto;
(c) defining the pattern on the other side of the strip in mirror image registry with the pattern on the first side by the application of an acid resistant coating to the other side of the strip;
(d) chemically milling both sides of the strip to selectively open areas therethrough and thereby to produce a plurality of the interconnected electrical contacts within a portion of the strip;
(e) attaching a body of insulating material to selective portions of the strip to secure the electrical contacts to the body;
and
(f) severing the electrical contacts from each other and from adjoining portions of the strip.

4 more elements

A method of producing a multiple contact stator for a rotary switch, the method comprising the steps of:

(a) producing an enlarged pattern for fabricating a plurality of interconnected electrical contacts within a portion of a strip of metal;
(b) reducing the enlarged pattern to an actual size pattern on a phototransparency;
(c) producing a mirror image pattern of actual size on a second phototransparency;
(d) superimposing the phototransparencies with the emulsion surfaces thereof proximal to each other and with the patterns thereof in registry;
(e) coating both surfaces of the strip of metal with a photoresist material;
(f) inserting the coated strip between the phototransparencies;
(g) exposing both phototransparencies to a light of a wave length to which said coated surfaces are photosensitive and thereby selectively exposing portions of both of the coated surfaces as determined by the patterns on the respective photoransparencies;
(h) developing both coated surfaces;
(i) chemically milling both surfaces of the strip to selectively open areas therethrough and thereby to produce a plurality of interconnected electrical contacts within a portion of the strip;
(j) molding a stator body of insulating material to both surfaces of selective portions of the strip to secure the electrical contacts to the stator body;
and
(k) severing the electrical contacts from each other and from adjoining portions of the strip of metal.

9 more elements

Dependencies are inferred from the claim text.

Method of making an electrical switch and chemically milled contacts

Life of this patent

Method of making an electrical switch and chemically milled contacts

Life of this patent

Abstract

Claims8