| 摘要 |
1,061,400. Hydraulic presses. ZAVODY V. I. LENINA PLZEN, NARODNI PODNIK. Nov. 30, 1964 [Dec. 3, 1963], No. 48531/64. Heading B5F. [Also in Division F1] An hydraulic system for controlling the movement of, e.g., a press plunger 1, comprises a filling valve 9 and distributing valves 4, 5, 6 operable in combination to stop, start, extend or return the plunger 1 by a piston 23a and the pistons 24, 25, 26 of servomotors 12, 13, 14, each movable by slide valves 15, 16, 17 arranged to coact with blocking slide valves 27, 28, 29 to ensure that the spaces 37, 38, 39 below the pistons 24, 25, 26 when unpressurized are always connected to the tank so that operation of the servomotors due to valve leakage &c. is precluded. As shown, the plunger 1 is stationary. To move the plunger 1 to the left the distributing valve 6 is opened to allow liquid in a line 18 connected to the return plungers 2 to pass to a tank 7, and low pressure liquid in a line 8 to pass to the plunger 1 through the filling valve 9 and a line 19. To continue movement at an increased rate the valve 4 is opened to direct highpressure liquid from a line 3 into a line 21 connected to the line 19. To return the plunger the distributing valves 4 and 6 are closed and the valve 5 is opened whereby high-pressure liquid in the line 3 passes to the line 18 and to a line 22 to upwardly move the piston 23a which opens the valve 9 to allow the plunger 1 to discharge liquid to the low-pressure line 8. The pistons 24, 25, 26 for opening the distributing valves 4, 5, 6 are each operated by moving the corresponding slide valve 15, 16, 17 into an upper position whereby control liquid pressure in a line 11 is directed to the respective spaces 37, 38, 39 below the pistons. In the position shown the spaces 37, 38, 39 are connected by the valves 15, 16, 17 to waste pipes 40, 41, 42. To operate the valve 6 the valve 17 is moved to connect lines 43, 44 whereby liquid from the line 11 flows to the space 39 through a path comprising a line 36, the blocking slide valve 28 and the lines 43, 44, 45. If for any reason the control slide valve 16 is changed, the space 39 is connected to the waste pipe 41 through the ducts 46, 44, 45 and the piston 26 returns to the position shown. Operation of the slide valve 15 in order to operate the distributing valve 4 interconnects ducts 49, 50. Hence pressure liquid flows from the line 11 through the ducts 36, 43, 44, 45, 49, 50 to the space 37 to lift the piston 24. Provided the valves 15, 17 are returned to their positions shown, the slide valve 16 can be lifted to operate the distributing valve 5. If either valve 15 or 17 is operated the space 38 is connected to the waste pipe 40 or 42 and cannot be operated. |
