bore communicating with the internal cavity the enlarged outer end 6 of the axial bore is provided with internal threads which threadingly receive the external threads of a cylinder 5 located in a chamber of cylinder 5 is a piston 7 one end having a stem 8 projecting through the small portion of the axial bore to contact the end of slider latch c the other end being exposed to a manifold 10 which receives the force of an actuating charge or other pressure the open end of body a may be closed by any conventional removeable end closure means such as end plate 11 and end cover 12 a threaded member 13 extends through aligned bores in end plate 11 and ears 12a of end cover 12 the narrow edge wall of body a is provided with recesses 14 to receive resilient fingers on the ends of plate 11 as is well known in the art the slide walls of body a are provided with a pair of transversely aligned apertures 15 15 one of which has an enlarged counter bore by means of apertures 15 15 the body a is telescoped over the cylindrical portion of guide sleeve b unitl the counter bore is engaged with an enlarged intermediate collar 16 on guide sleeve b by threaded engagement 17 of the external threads of guide sleeve b with the internal threads of a cup like spring cover 18 the body a is retained in position within the cover 18 is a compression spring 24 surrounding rod portion 19 of follower d an enlarged plunger portion 20 of.