Abstract: A series connection of an auxiliary switching position and a cut-on resistor is connected parallel to at least one primary switching position. A common drive rod is provided with which there is coupled a transmission system operatively associated with the primary switching position as well as a transmission system operatively associated with the auxiliary switching position. The transmission system associated with the auxiliary switching position comprises a cam cooperating with a follower or entrainment member mounted to an actuator rod leading to the auxiliary switching position. For positively controlling the sequence of movements without having to tension a spring during the cut-on of the auxiliary switching position the cam comprises a stationary cam or guide track containing a closed loop engaged by the follower member.

Abstract: A movable contact element is secured at the end of a thrust rod and therefore can be brought into and out of engagement with a fixed contact element. The free end of the movable contact element is surrounded by a blast nozzle which is likewise secured to the thrust rod. The inlet of the blast nozzle is operatively connected with a pump chamber containing an extinguishing gas and which can be pressurized during the course of a cut-off stroke of the gas-blast switch. This pump chamber is surrounded at its circumference by a cylinder which is displaceably guided upon a stationarily supported piston. To reduce the mass of the parts which are to be accelerated at the start of the cut-off stroke, the blast nozzle itself is constructed as a second piston situated opposite the first-mentioned piston and displaceable relative to the cylinder between two end positions.