| 摘要 |
1,011,758. Drilling machine details. SOC. D'ETUDE ET DE CONSTRUCTION DE MACHINE OUTILS. June 25, 1964 [July 5, 1963], No. 26297/64. Headings B3B and B3C. A drilling machine spindle 1 is moved axially at a fast approach rate by a pneumatic piston 8 10 , and the rate is reduced during drilling by a dashpot, comprising an hydraulic piston 16. The spindle is splined to a sleeve 2 at 1 10 , and the sleeve is driven through pulleys 3, 4 and belt 5, by an electric motor 6. A second sleeve 8 1 , 8 2 is axially displaceable with spindle 1 in a casing 13, and has the piston 8 10 , 16 1 secured thereto, or formed thereon. Sleeve 8 has an abutment 8 20 , and an adjustable stop nut 18, screwed thereon. Piston 16 slides in cylinder 17, the ends of which are connected through passages 19-21, the latter passage containing a throttling valve 22. Passage 21 is connected to an oil tank 25, and a by-pass passage 23 containing a one-way ball valve 24, is connected to the tank, and also to passages 19, 20. In operation, air is supplied to the right-hand end of cylinder 12, Fig. 1, and sleeve 8 along with spindle 1 is fed at a rapid rate. Nut 18 strikes the end of sleeve 16 which moves to force hydraulic fluid through passage 19, past valve 22, and into passage 20, and the feed rate is reduced. When the drilling is completed the air supply to cylinder 12 is reversed and the spindle is retracted at a fast rate, with the hydraulic fluid passing freely from passage 20 to passage 19 through by-pass 23. Sleeve 8 has a pin 28, Fig. 3, projecting from it which carries a collar 29. Adjustably mounted in the collar is a rod 30 with an actuator 31 secured thereto, for cooperation with a micro-switch 32 to reverse the fluid flow to cylinder 12. A second rod 35 is adjustably carried by collar 29 and supports an actuator 34, which co-operates with a second micro-switch 33 to operate an audible or visual signal, which indicates that sleeves 8 and 16 have returned to their initial positions, Fig. 1. The starting switch in the control circuit may be cam-actuated, and a manual switch may also be provided. A delayed opening relay for switch 32 may be provided where it is desired to cause spindle 1 to dwell in its advanced position. |
