Switching device

• US 4,000,480 A
• Filed: 03/31/1975
• Issued: 12/28/1976
• Est. Priority Date: 03/31/1975
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Inventors: McCaughan, Daniel Vincent, Gray, Eoin Wedderburn
• Primary Examiner(s): Broome, Harold
• Application Number:
  US05/563,801
• Time in Patent Office: 638 Days
• Field of Search: 335/201, 335/129, 335/200, 200/146 R
• US Class Current: 335/129
• CPC Class Codes: H01H 1/56 Contact arrangements for providing make-before-break operation, e.g. for on-load tap-changing

Abstract

A switching device includes a combination of a fixed contact, first and second electrically connected movable contacts, and an arrangement for moving the movable contacts so that the first movable contact closes to the fixed contact before the second movable contact closes to the fixed contact and so that the first movable contact opens from the fixed contact after the second movable contact opens therefrom.

Claims

1. A relay comprising:

a fixed contact;

first and second wire springs each wire spring having a free end and a fixed end, the wire springs connected electrically at their fixed ends;

a contact attached to the free end of each of the wire springs; and

an insulating armature card means moving the free ends of the two wire springs so that the contact of the first wire spring closes to the fixed contact before the contact of the second wire spring closes to the fixed contact and so that the contact of the first wire spring opens from the fixed contact after the contact of the second wire spring opens from the fixed contact.

2. A relay in accordance with claim 1 wherein the insulating armature card means includes a recess for positioning the first wire spring closer to the fixed contact than the second wire spring is to the fixed contact when the contacts are open.

3. A relay in accordance with claim 1 wherein the contact of the first wire spring is of a material which resists erosion caused by electrical arcs.

4. A relay in accordance with claim 3 wherein the electrical erosion resistant material is an alloy of palladium-nickel.