| 摘要 |
<p>1,194,983. Hydraulic actuators. P.S. DOISTUA and C.A. GOIRI. Aug.27, 1968 [Nov. 23, 1967], No.40850/68. Heading F1P. [Also in Division B3] A rotary machine tool head 1, 2 having a fluid operated actuator piston 16 for operating a chuck, is provided with a rotary part 3 which includes a valve assembly, Fig. 4, supplied with oil under pressure when the actuator is to be operated and arranged to trap oil in the actuator when the oil supply is cut-off. The actuator piston 16 slides in a cylinder defined by the rotary parts 1, 2, 3 and divides the cylinder into chambers 15, 23. The oil is trapped in these chambers when the oil supply is cut-off and hence the actuator is locked in its adjusted position. To operate the actuator oil is supplied to the valve assembly through one or other of ducts 11, 21 by selective pressurization of annular grooves 9, 19 in a stationary block 4. Assuming the duct 11 is pressurized, then the right hand non-return valve 37 opens to allow oil to flow through ducts 12, 13, 14 into the actuator chamber 15. The increase in the oil pressure in the duct 11 causes leftwards displacement of a piston 27 and consequential opening of the left hand non-return valve 37 so that oil in the opposite chamber 23 exhausts through ducts 22, 21. If the duct 21 is pressurized, oil flows to chamber 23 for operation of the actuator in the reverse direction.</p> |
