Abstract: A stair lift eliminates a hindrance to the normal use of a staircase. The stair lift comprises two rails disposed along the staircase in parallel to the width of the staircase, a self-propelled gantry-shape carriage having a gantry-shaped structure, traveling on the rails with a restriction to prevent a derailment, and a lift step (1) disposed between left and right leg structures of the gantry-shape carriage and supported by a lifting mechanism provided in the leg structure. When the gantry-shape carriage stands by at a lower floor or a upper floor of the staircase, the lift step (1) lands on the floor adjacent to the staircase or a step of the staircase, and when the gantry-shape carriage travels on the rails, the lift step is held at a position preventing an interference with steps of the staircase. A user gets on the lift step (1) while standing.

Abstract: A stair lift eliminates a hindrance to the normal use of a staircase. The stair lift comprises two rails disposed along the staircase in parallel to the width of the staircase, a self-propelled gantry-shape carriage having a gantry-shaped structure, traveling on the rails with a restriction to prevent a derailment, and a lift step (1) disposed between left and right leg structures of the gantry-shape carriage and supported by a lifting mechanism provided in the leg structure. When the gantry-shape carriage stands by at a lower floor or a upper floor of the staircase, the lift step (1) lands on the floor adjacent to the staircase or a step of the staircase, and when the gantry-shape carriage travels on the rails, the lift step is held at a position preventing an interference with steps of the staircase. A user gets on the lift step (1) while standing.

Abstract: A puffer type gas-blast circuit breaker includes at least one interrupting unit mounted in a vessel filled with an arc-extinguishing gas of a unitary pressure.