Abstract: Within an envelope, the medium or high voltage circuit breaker includes first and second main contacts that are movable relative to each other along a common axis, first and second arcing contacts that are movable along the common axis, the first arcing contact being secured to the first main contact, and a device for transmitting displacement to the second arcing contact in a direction opposite to the displacement of the first main contact and the first arcing contact. The device includes two wheels mounted in fixed positions in the circuit breaker and in alignment on the common axis, and a transmission belt looped around the two wheels, thereby enabling the second arcing contact to be displaced relative to the first contacts by means that occupy little space.

Abstract: This present invention concerns a circuit-breaker of the self-blasting type including a system for immobilizing the semi-mobile piston during a first part of displacement of the mobile contact assembly between the closed position and the open position and for displacing the piston axially during a second portion of the same displacement of the mobile contact assembly. This system includes at least one first longitudinal slot and at least one second longitudinal slot on the fixed tube, a freely rotatable locking tube carried by the fixed tube, aligned with the slots thereof and including at least one first longitudinal slot and at least one second longitudinal slot, at least one pin carried by the second tube and penetrating the first slot of the fixed tube and the first slot of the locking tube, and at least one pin carried by the piston and penetrating the second slot of the fixed tube and the second slot of the locking tube.

Abstract: The present invention relates to an electrical contact system, in particular for a circuit-breaker, for establishing electrical contact between the respective ends of two conductive tubes (1) and (3) by fitting them together so that the end of one tube is inserted into the end of the other tube. According to the invention, one of the tubes (1), (3) includes a cavity (4) at its end, the cavity having an opening facing the other tube (3), (1) over at least a portion of the periphery of the tube, and a conductive component (2) is held in said cavity (4) which component is in part deformable radially relative to the tube, the conductive component coming into contact with the bottom of the cavity, and projecting out from the opening in the cavity.