Patent GB-471201-A (GB)
Title: Hydraulic drive for machine tools
IPC: B23D7/00
Filed: 1936-03-02
Abstract: 471,201. Hydraulic transmission of power. KLOPP, F. March 2, 1936, No. 6348. Convention date, March 2, 1935. [Class 69 (ii)] In hydraulically operated machine tools, one side of the working cylinder is, during one direction of motion, connected by a pipe 20, Fig. 1, ports 43 and ports 12 to an oil tank, and through a passage 8 to a space on the right of the piston 16 of the main distributing valve 6. The other side of the working cylinder is supplied from a pump through ports 1, 4, 28, 7. When the working piston approaches the end of its stroke, it causes an auxiliary valve 10, 11, to move to the right by means not shown, and close the outlet ports 43. Pressure builds up to the right of the piston 16, and moves the valve 6 to the left against the action of the spring 15. The port 7 is thus put into communication with the tank through a port 18, and the pump supply passes through the ports 28 and passage 8 to the pipe 20, so that the working piston is reversed. At the end of the return stroke, the valve 10, 11 is returned to its initial position, thus putting the passage 8 to exhaust, and allowing the spring 15 to return the main valve ; the latter has a piston 17 of smaller area than the piston 16 so that pressure between them aids the spring action. The valve 11 is slidably mounted on the member 10, and in its end positions, a notch 13 or 14 is engaged by a spring-pressed ball 19. The member 10 has pistons 100, 101 controlling the connection of pipes 102, 103 to pressure and exhaust, said pipes being connected to devices for adjusting the pump delivery. A valve 3 has a pin 55 normally'engaging a recess 70. To stop the machine, the valve is moved against the action of a spring 53, turned slightly, and released. The spring then moves the valve, the pin 55 travelling on the incline 71, and the supply port 1 is put into communication with the port 18 leading to the tank. The Specification as open to inspection under Sect. 91 comprises also the form shown in Fig. 3 (Cancelled), having a main valve 18, a valve 79, and an auxiliary valve 80. When these valves occupy the positions shown, liquid from a pump passes through a channel 41, the annular space 95 of the main valve, ports 52, a channel 51, and a pipe 50 to one end of the working cylinder. The channel 51 also communicates through a channel 57 with the space 22 to hold the main valve in position. The other end of the working cylinder communicates through a pipe 47, channel 65, annular space 34 of the auxiliary valve and grooves 25 in the valve 79 with the oil tank. When reversal is to take place, the auxiliary valve is moved to the right; the channel 51 and space 22 are then put into communication with the oil tank, and the main valve is moved to the right by the spring 91, the action being assisted by pressure liquid admitted to act on the left side of the piston 85. Pressure liquid then proceeds to the working cylinder through the pipe 47, and exhaust liquid returns through the pipe 50. When the auxiliary valve is returned to its initial position, the pressure of liquid accumulating in the space 38 is led to the space 22 and returns the main valve to the position shown. The valve 79 may be moved so that liquid flowing from the working cylinder is introduced into the pump delivery. This subject-matter does not appear in the Specification as accepted.