Patent GB-186358-A (GB)
Title: Improvements in radial drilling machines
IPC: B23B39/12
Filed: 1921-03-21
Abstract: 186,358. Conradson, C. M. March 21, 1921. Drilling-machines.-The radial arm swings on ball bearings on a sleeve 26 which is moved up and down the column 24 by screw and nut gearing 31, 32 driven by a reversible motor 36 mounted on the column. The arm is split at 47a and is clamped to the column by means of bolts 38, which are arranged to be actuated simultaneously by one handle (not shown). The arm is composed of two parallel members 45, 45a, between which the drill spindle and its changespeed gearing, mounted in an oil-bath housing 52, are adjusted radially by rack-and-pinion gear 61, 62 and a hand-operated worm 58. The housing is supported by roller bearings 53a and guided by slots in its bottom plate 55 coacting with guides 54 on the arm. Clamps 62a are provided for the housing on the arm. The drill spindle 160, counterbalanced by weights 173a, is rotated by a sleeve 48 which is driven by a reversible motor 64 through gearing designed to give sixteen speeds. Two different-sized pinions 69, 70, on the motor shaft gear respectively with toothed wheels 71, 72, loose on a hollow shaft 50 within which moves a rod 87 carrying clutch members 83, 84 adapted to be engaged with corresponding internal clutch surfaces on the wheels 71, 72. The rod 87 is moved to disengage the clutch by means of a dog 90a pivoted on the shaft 50 and rocked by the action of a collar 93 moved by a hand-operated rock-shaft 97 carrying a fork 96. The shaft 50 drives an intermediate shaft 49 by means of one of four sliding wheels 109 - - 112, engaging one of the wheels 109a - - 112a, fixed on the shaft 50. The handles 125, 131, for operating the sleeves 107, 108 are provided with interlocking segments as shown, so that the movement of either handle locks the other in its neutral position. The intermediate shaft 49 drives the spindle sleeve 48 through a two-speed gear; toothed wheels 138, 139, fast on the shaft 49 gear with wheels 140, 141 loose on the sleeve 48, on which slides a clutch sleeve 146, moved by a hand-operated rock-shaft 155 and a link 153 to engage one or other of the toothed wheels 140, 141. The spindle is fed by a nut 164 attached thereto and working over a feedscrew 169 journaled in the housing 172 and driven from the intermediate shaft 49 by gearing giving eight speed changes; sixty-four speeds of the feed-screw 169 are thus obtainable. For this purpose two wheels 196, 197, fast on the feed-screw gear with wheels 194, 195 loose on a hollow shaft 178 and attachable thereto by a spring key 198 which is operated by a rod 203 inside the hollow shaft, a lever 205, and a handle (not shown) mounted on the hand-wheel 204. The shaft 178 is driven by a pinion 191 through which slides an adjustable, shaft 192 carrying four wheels 184a, - - 187<a>, in gear with four wheels 184, - - 187 on a counter shaft 183 driven by the shaft 49. Any one of the four wheels 184a - - 187a can be locked to the shaft 192 by a second spring key (not shown) operated by sliding the shaft 192 vertically, which motion is effected by means of a circular rack 216, bevel-gearing and a handwheel 223, The shaft 178 may be operated by a hand - wheel 204, the power feed being disconnected by releasing a friction clutch which connects the shaft 178 to the toothed wheel 103 driving the pinion 192 This may be done by means of a handle 232, or automatically at desired point by means of a nose 245 mounted on an adjustable disc 242 rotated by a worm 236 so as to move a spring bolt 248 and thereby release the friction clutch through a lever 250 and link 251.