| 摘要 |
<p>1,038,934. Machine tool feeds. HAHN E.C., [trading as INDEX-WERKE KOMM GES. HAHN & TESSKY]. March 15, 1965 [March 17, 1964], No. 10844/65. Headings B3B and B3T. [Also in Division F1] Rapid advance followed by slow working advance of a tool-carrying piston 24, Fig. 1 (not shown), towards a workpiece 114 is effected by admitting pressurized hydraulic fluid through the inlet 72 of a stepped piston valve 54 and a duct 32 leading to a chamber 50 on one side of a control piston 46 to displace fluid from a control cylinder chamber 32 through a duct 30 leading to the actuator cylinder chamber 28 to effect said rapid advance of piston 24 until such time as the control piston 46 is arrested by an adjustable stop 48 whereon the resulting-pressure rise in chamber 50 opens a check valve 62 in a throttled branch duct 58 of duct 52 connected to the duct 30 and hence to chamber 28 to effect said slow advance of piston 24 until the latter is arrested by an adjustable stop 40. Movement of the valve piston 64 from its neutral position against a spring catch 84, 86 is effected by a rotary cam 88 driven by the work spindle 16 and on completion of the slow advance of piston 24 the resulting pressure rise in duct 30 is transmitted through a branch duct 106 to one side of a return piston 94 for moving the valve piston 64 to its neutral position thereby connecting ducts 30, 106, 58 and 52 to the valve outlet 74; excess pressure being relieved from control chamber 32 through a check valve 56. In a modification a second actuator 120, Fig. 2 (not shown), and control unit 124 serve to traverse the tool holding piston and cylinder in a direction normal to that of advance and in a further modification a tray 180, Fig. 3 (not shown), is postioned to receive portions cut from the workpiece.</p> |
