GB432005A - Improvements in and relating to the operation of machines having a reciprocating main motion - Google Patents

Abstract

432,005. Hydraulic transmission of power. WALDRICH, A., 68, Hahnweg, Coburg, Germany. Jan. 5, 1935, No. 454. [Class 69 (ii)] In a machine having a part reciprocated by hydraulic means comprising a primary pump reversed by a hydraulic servomotor, a main valve is actuated manually or from the machine part for securing the reversal of the servomotor and pump, and another valve operated from the servomotor coacts with the main valve when the latter is put into its mid-position to stop the drive. The primary pump 2, Fig. 1, may be moved to reverse and vary its output by means of a nut 6 engaging a screwed spindle 5, the nut being fixed to the spindle of a servomotor having a vane 7 and the spindle being provided with an arm 9 coacting with adjustable motion-limiting stops, and with a sprocket wheel 10. Pressure liquid for operating the servomotor is derived from an auxiliary gear-wheel pump 30, Fig. 3, and the circuit includes a main valve 17 and a valve 20, the latter being connected to the servomotor spindle by a sprocket chain. One end of the valve 17 is formed as shown in Fig. 4, to control connection between pipes 15, 16 and a suction pipe 33, while the other controls connection between the pressure pipe 29 and the valve 20. A pressure-relief valve 31 is provided, and the lever 25 for operating the valve 17 may be actuated manually or by movable dogs 26, 27. When the valves 17, 20 occupy the positions shown in Fig. 3, the vane 7 and pump 2 are in mid-positions and the hydraulic drive is interrupted, since the pump 2 is not delivering. By moving the lever 25 into the position T or U, the valve 17 is turned to establish connections for moving the vane 7 and pump 2 into an end position. If desired, the servomotor may consist of a cylinder with a piston or piston rod having a rack to turn the nut 6.