Abstract: A reciprocating saw blade moved in opposite directions parallel to a longitudinal axis is formed with at least one row of longitudinally succeeding teeth having tips all lying on a common tip line parallel to the longitudinal axis and including even teeth all oriented in one direction parallel to the axis and odd teeth alternating with the even teeth and all oriented in the opposite direction parallel to the axis. Each even tooth forms with one of the adjacent odd teeth a double tooth and the tips of the teeth of each double tooth are set laterally of the blade to one side with the lateral set by an offset that alternates longitudinally from double tooth to double tooth to opposite sides of a center blade plane. The offset is the same for all teeth. Each tooth has a relatively steep leading edge and a relatively shallow trailing edge, relative of course to the respective longitudinal direction.

Abstract: A leak resistant, switching, double valve system consists of two sliding valve bodies in a valve housing with connecting lines. The two sliding valve bodies, which can be actuated independently of one another, are in contact in the closed position with valve seats in the valve housing, and are located at some distance one behind the other, forming a leak cavity between them. During the opening process, the first sliding valve body, before it leaves its valve seat, while simultaneously reducing the size of the leak cavity, can be placed in contact with the second sliding valve body, which is provided with a tubular extension which exits the valve housing in a sealed manner and connects the leak cavity to the environment of the valve system.