Lock for trolley connector

Claim 1

A locking apparatus for electrically isolating a trolley-type electrical connector on the end of a conduit on an electrical machine to prevent an electrical connection from being made with the connector, the apparatus comprising: an open-ended sheath, made from an electrically insulating material, adapted to be slidably mounted on the end of the conduit, to slide between an extended position in which the sheath surrounds the connector, and a retracted position in which the connector projects through the open end of the sheath; electric insulating means for releasably blocking the open end of the sheath to enclose and retain the connector in the sheath; and first stop means on the conduit engageable by said sheath to stop the sheath in its said retracted position, said stop means serving to limit movement of the sheath relative to the conduit in a direction away from its extended position, said conduit comprises a tubular housing with opposite ends, and fuse means in the housing adapted for connection to said electrical connector with the connector extending from one end of the housing, said fuse means also being adapted for connection to an electrical conductor with the conductor extending from the other end of the housing for delivery of electric power to the machine, said sheath being slidable on the outside of the housing relative to the housing and relative to the electrical connector and conductor between its said extended and retracted positions.