23,818. Carolan, E. A., [General Electric Co.]. Nov. 3. Shaping; lathes; air and steam, apparatus for actuating machines by.-Compressed air or steam is used to operate shaping and like machines directly, the intervention of a water, oil, or other liquid piston being stated to do away with shock when passing over holes or spaces in the line of cut. The invention is stated to be applicable to machine tools such as lathes by making the apparatus double-acting and converting the reciprocating into rotary motion. In the construction shown in Fig. 1, air is supplied through a three-way cock, controlled by an arm 20 and tappets 21, 22, to a reservoir 16 in the frame, containing the liquid. The reservoir communicates by a passage 15 with a chamber provided with a valve 24 which controls the opening to a pipe 14 communicating with the cylinder 8, forming part of the ram, beyond the fixed piston 9. An outer tube 11 forms the pistonrod, and the small annular space 30 is always open to the air pressure to furnish the return stroke. The valve 24 is operated by a screwed spindle 25 ; guide-pins 27 prevent the valve from rotating, and a spring 29 is interposed between the valve head and the spindle end to allow the valve to be opened wide by the outflowing liquid on the return stroke. The position of the valve 24 controls the speed of the tool. A disc 36 with an adjustable crank-pin is oscillated by the arm 20 and controls the motion of the compound work table 2. A cock 8<3> provides for the removal of all air from the cylinder 8. The construction shown in Fig. 6 does away with a reservoir in the pedestal and economizes air when working on short strokes at the out position of the ram by avoiding the opening of a large volume of pressure air to the exhaust. The cylinder 8 is provided with a movable front end 40 operated by a screw and gearing 44. A crosshead 47 prevents the end 40 from rotating, and has connection through a slot with an arm on the exterior of the cylinder which indicates the position of the movable end and carries one of the tappets. The valve 24 is located in the piston 9, the liquid being contained between the end 40 and a floating piston 55. Liquid is introduced originally, and any subsequent leakage is made good, by way of the hollow valve-rod 25, which communicates with a chamber 52 fed by a pipe. Removal of air takes place by a pipe 48 leading through the screw of the end 40 to an aperture in the crosshead closed by a screw. Air for the return stroke is supplied from a chamber 63 through passages in the tube 11, and for the operative stroke through a valve 58, which also opens to exhaust at 59. The valve is operated by an arm on its spindle linked to the arm 20, which is arranged as in Fig. 1.