GB931691A - Hydraulic control device for two non simultaneous displacements - Google Patents

Abstract

931,691. Milling. FABRIQUE DE MACHINES MIKRON S.A. May 14, 1962 [Sept. 1, 1961], No. 18533/62. Class 83 (3). [Also in Group XXIX] An hydraulic control device for two non- simultaneous displacements comprises two coaxial pistons 6, 7, each slidably mounted in a chamber 4, 5 of a cylinder 1, 2 and urged away from the other by an elastic device 20 between the pistons, the feeding of fluid under pressure to one of the chambers being controlled through the displacement of the piston sliding in the other chamber. The device may be applied to a machine tool having a cutter F carried on a lever 37 connected by a pivot 38 to a slide 39, the lever being rocked by a member 43 operated by the piston 6 and the slide being moved by the piston 7. The piston 6 is movable against the elastic device 20 by fluid pressure supplied to the chamber 4 from a pump 21 under the control of a valve 22 and a regulator 23, and during its movement causes a part 14 to engage the member 43 which is rocked about a pivot to displace a pin 43 engaging an adjustable pin 46 on the lever 37 to raise the cutter F. Towards the end of the movement of the piston 6, a land 17 uncovers a passage 28 to enable fluid from the pump to pass through a passage 25 into the passage 28 which has a regulating valve 29 controlling the flow to the chamber 5 so that the piston 7 moves against the elastic device, the piston being connected to the slide by an arm 41 secured to a threaded extension 8 of the piston. The extension 8 of the piston carries a ring 32 which is held in contact with springs 35 by an adjustable nut 34 and carries an arm 33 having an adjustable screw 36 co-operating with a microswitch M, operation of which stops the pump and reverses the valve 22 to permit the elastic device 20 to return the pistons to their original position. A one-way valve 11 prevents return flow through the passage 25 and prevents the piston 7 returning to its original position until after the fluid has been exhausted from chanber 4 and the land 17 permits fluid from chamber 5 and passage 28 to pass to an exhaust passage 31. One-way valves 27, 30 permit the flow from the chambers to by-pass the regulating valves 23, 29 and the pistons to rapidly return to their original positions. In an alternative embodiment, the piston 7 is not connected to a movable member and its movement serves to control the time the piston 6 is in its advanced position.