Abstract: A power transfer switch in which a cross bar including a movable contact is rotated to come into contact with one of fixed contacts disposed on left and right sides of the cross bar. The cross bar has a non-circular cross-section including a protruded piece on left and right, and a rotating angle thereof is greater than a rotating allowable angle of the movable contact between the fixed contacts. A through hole into which the cross bar is inserted with play is formed on a base portion of the movable contact, and a step portion for receiving the protruded piece of the cross bar and a spring housing portion extended in a direction of a central axis of the movable contact are formed in the through hole. A compression spring is accommodated in the spring housing portion to cause the cross bar to elastically hold the movable contact.

Abstract: A power transfer switch in which a cross bar including a movable contact is rotated to come into contact with one of fixed contacts disposed on left and right sides of the cross bar. The cross bar has a non-circular cross-section including a protruded piece on left and right, and a rotating angle thereof is greater than a rotating allowable angle of the movable contact between the fixed contacts. A through hole into which the cross bar is inserted with play is formed on a base portion of the movable contact, and a step portion for receiving the protruded piece of the cross bar and a spring housing portion extended in a direction of a central axis of the movable contact are formed in the through hole. A compression spring is accommodated in the spring housing portion to cause the cross bar to elastically hold the movable contact.

Abstract: In construction of a switching device interposed between a pair of power sources and a load circuit and provided with switch and by-pass units, the switch unit is extractable from its housing and operation of the by-pass circuit is interlocked with position of the switch unit with respect to the housing so that the load circuit should be selectively connected to one of the two power sources. For convenience in maintenance and/or operation of device elements, shift of connection of the load circuit from one to the other power source can be performed by an interlocked operation of the two units without any contact damage and incorrect power source connection.

Abstract: This transfer switch has movable contactors moving to connect a load side fixed contactor alternatively to two different current source side fixed contactors. The movable contactors are operatively connected with a control shaft moving along either inclined path of a substantially V-shaped guide groove and the current source selected by the movable contactor is determined by which inclined path of the guide groove the control shaft follows. The inclined path along which the control shaft moves is determined by the direction of the inclination of a point plate closing the inclined path by inclining to either side. The control shaft rises along either of the inclined paths of the guide groove as operatively connected with a rotating motion against a returning spring by a manual or electric operation of an operating lever. When the operating lever is in the original position, the control shaft will be positioned in the middle of the guide groove and the movable contactors will be in neutral positions.