| 摘要 |
872,617. Drilling and tapping machine details. WALSH, R. W. July 20, 1959 [Oct. 23, 1958], No. 24816/59. Class 83 (3). In a drilling, tapping, &c. machine, the tool is driven through a yielding- coupling which slips continuously during the cutting operation and is given rotational impulses so that the cuttings removed are flaky or powdery and the tool breaks through without leaving a burr on the work. Heating of the tool is also said to be reduced. The machine comprises a column 10, Fig. 1, supporting a vertically-adjustable work-table 11 and a drilling-head 14 having a motor 17 which drives the spindle 21 through a belt 20 and pulleys 19, 22, the pulley 22 being splined to the spindle 21. The spindle 21, Fig. 3, drives a spindle 48 through a fluid coupling 54 which includes a top and bottom housing 55, 56 secured together by screws 57, and secured to the spindle 48 by screws 58. A rotor 59 in the coupling 43 has an integral shaft 62 which is connected to the shaft 21 through flanges 67, 68 and pins 70. The spindles 21, 48 are supported by a bracket 45 which moves vertically with the spindles during feeding of the tool, which may be manually by rack and pinion 25, 27 or by a split-nut 41 engaging a screw 38 rotated by a worm and wheel 39, 37 driven from a motor 35 and a variable speed transmission box 34. In operation the spindle 21 is rotated at constant speed, to drive the rotor 59, and the housings 55, 56 connected to the spindle 48 at 51 being driven at a reduced speed due to slipping between the rotor and the housings, the amount of slipping depending on the quantity of fluid in the spaces 73, 60. The housing 55, and the rotor 59 have vanes 72, which when the fluid passes during differential rotation of the two parts produces pulsing of the spindle 48. In a modification, pulsing is produced by an airjet which engages vanes on the housing. In a further modification, pulsing is produced by intermittently restraining the spindle 48, Figs. 6, 8, by pistons 82, in a non-rotary member 79, fluid-pressure being supplied to the pistons through a conduit 86. The inner ends of the pistons engage a sleeve 96 having a cam 97 and as the spindle rotates the cam intermittently moves each piston against the fluid pressure. |
