Electric switch

• US 4,357,509 A
• Filed: 09/15/1980
• Issued: 11/02/1982
• Est. Priority Date: 09/18/1979
• Status: Expired due to Term

• Current Assignee: ASEA AB Vasteras Sweden
• Original Assignee: Asea Aktiebolag (ABB Limited)
• Inventors: Adlerteg, Bo
• Primary Examiner(s): Price, William
• Assistant Examiner(s): Elkins, Gary E.
• Application Number:
  US06/187,340
• Time in Patent Office: 778 Days
• Field of Search: 200/163, 200/164 R, 200/153 M, 200/240, 200/255
• US Class Current: 200/240
• CPC Class Codes: H01H 1/18 with subsequent sliding
• CPC Class Codes: H01H 1/365 Bridging contacts
• CPC Class Codes: H01H 3/001 Means for preventing or breaking contact-welding
• CPC Class Codes: H01H 9/32 Insulating body insertable between contacts

Abstract

An electric switch, for example a load switch or safety switch for low voltage, has at least one fixed contact member and two movable contact members, which form parallel current paths and which, in the closed position of the electric switch, are pressed against the fixed contact member on opposite sides thereof under the influence of contact pressure springs. Closing and opening are accomplished by means of a wedge-formed element which is displaceable between the movable contact members, said element being arranged on an operating member linearly displaceable between two end positions. The movable contact members are guided in the switch body in such a way that they move perpendicular to the direction of displacement of the operating member. The movable contact members are of elongated cross-section and have defined contact surfaces and break points. Upon closing and opening of the switch, the movable contact members are forced to rotate with respect to the fixed contact member, which results in a reduced risk of contact welding.

Claims

1. In an electric switch comprising a switch body, at least one fixed contact member mounted on the switch body, two elongated, substantially parallel, movable contact members which, in the closed position of the switch, are pressed under the influence of contact pressure springs against said at least one fixed contact member on opposite sides thereof, a wedge-shaped element displaceable between the movable contact members for opening and closing the switch, said element being arranged on an operating member which is linearly displaceable between two end positions, and means guiding the movable contact members in the switch body in such a way that, during the displacement of the operating member, they move substantially perpendicular to the direction of displacement of the operating member, the improvement according to which said movable contact members are of elongated cross-section and are guided between said wedge-shaped element and said contact pressure springs for rotation with respect to said at least one fixed contact member during both contact closing and contact opening, thus achieving a rolling contact movement.

2. An electric switch according to claim 1, comprising two fixed contact members arranged in spaced relationship to each other, said movable contact members forming a contact bridge between said fixed contact members, and said movable contact elements are provided with guiding lugs for guiding said wedge-shaped element in between said movable contact members.

3. An electric switch according to claim 2, in which said movable contact members are constructed so that the distance between the middle portions is smaller than the distance between the contact surfaces of the members, which contact surfaces are positioned on opposite sides of said fixed contact member.

4. An electric switch according to claim 1 or 2, in which locating pieces for said movable contact members are arranged between said contact pressure springs and said wedge-shaped element.