The apparatus for generating acoustic also includes at least one axial driver coupled to each moment arm, wherein each axial driver aligns with a longitudinal axis of the housing.

An axial drive screw is centrally located in the mast assembly for extending and retracting the tubular sections.

The axis control circuit (18) is adapted to receive this interpolation pulse signal CP, generate a speed command for each axis and send the commands to a servo amplifier (19).

A middle support member is used to provide axial support and control to the tie shaft.

A switching element (7) that is located laterally in relation to the pushbutton (1.1) is actuated (2) with the aid of an annular lever (5) by the axial actuation of the knob.

Disclosed is a valve-controlled axial piston expansion machine (10) comprising a system of two or more cylinders (12,14) that are grouped around a common central axis (16).

The arrangement is like a cartridge and the valve spindle is controlled axially, which is a common solution in connection with thermostat valves for radiators.

The rotatable ramp structure (50) is supported on the housing-fast ramp structure (40) in such a way that it converts a torque exerted on it by the shaft (34) into an axial actuating force (B).

The inventive machine is characterized in that the valves (86, 94) and the valve stem (82; 116) are disposed on the side of the cylinders (12, 14) facing away from the common central axis (16).