Patent GB-500485-A (GB)
Title: Improvements in and relating to drilling and tapping machines
IPC: B23B39/12
Filed: 1937-08-09
Abstract: 500,485. Drilling and tapping machines. HEIDE, H. C. (Schauer. L. L., and McKewen), J. H.) Aug. 9, 1937, No. 21889. [Class 83 (iii)] In a drilling and tapping machine a manuallyoperable control device is provided which is adapted to feed the spindle axially in either direction and also control rotation of the spindle, so that the rotation can be started stopped or reversed by the device irrespective of the direction in which the spindle is fed thereby. An electric motor on the radial arm 13 rotates a shaft 16 which drives the spindle 18 through change gearing in the head. A shaft 38 is driven through further change gearing from the spindle and rotates a worm wheel 36 loose on a shaft 22 carrying a pinion 23 which engages rack teeth 18b on the quill. The wheel 36 may be connected to the shaft 22 by a cluth comprising levers 25 pivoted on a head 24 attached to the shaft and carrying offset toothed portions 32, Fig. 6, engageable with internal serrations on a ring 35 attached to the wheel. Springs 25a normally maintain the clutch disengaged, but the levers may be rocked to start a power feed by means of radial pins 26 and an axially movable central cam 31. Teeth 29 on the cam engage toothed segments on the ends of hand feed levers 27 pivoted at 27a on the head 24, the position c in Fig. 3 of the levers corresponding to power feed whilst in positions d, f, n, r, the clutch is disengaged and the pinion 23 may be rotated by the levers 27 for hand feed. A central rod 51, which is prevented from rotating, abuts on the cam and carries rack teeth 52 meshing with a pinion 50 on a shaft 49 connected by a toothed segment and pinion to a shaft 46, Figs. 7 and 8, carrying cams 44, 45. Plungers 42, 43 engage the cams and operate switches A1, A2, Fig. 5, which control solenoids R, F, for starting the driving motor 15 for the shaft 16 in either direction. When the hand levers 27 are in position c, Fig. 3, the cams engage the plungers 42, 43 at e<1>, Figs. 7 and 8, and the switch A1 is closed for forward rotation of the tool spinde 18, the power feed being stopped when the levers are moved to position d, but the spindle rotation continuing with the plungers in position d<1>. These two positions of levers 27 are for controlling the feed during drilling operations. For tapping, the levers 27 are moved to positions f, n, r in the first of which the spindte is still rotating forwardly whilst plunger 43 engages a detent recess 45p in the cam 45 (position f<1>), and in the second both switches A1, A2 are open to stop rotation of the spindle (position n<1>), whilst in the last, switch A1 is open and switch A2 closed for reverse rotation of the spindle (position r<1>). In any of positions f, n, r the spindle may be hand fed or withdrawn by rotation of the levers 27, a graduated dial being provided on the head 24 adjacent a flange 39a, Fig. 3, fixed in adjustable positions to indicate the depth of feed. The tap feeds itself during the tapping operation. The radial arm 13 may be clamped to the pillar sleeve (not shown) by means of a handle 19. Fig. 5, which is interlocked with switches C1, C2 for starting the motor 15 in forward or reverse directions to raise or lower the arm by power when it is unclamped, a further switch C1 being interlocked with switches C1, C2 to cut put switches A1, A2 and prevent actuation of the spindle controls when the arm is unclamped. Automatic stop feed-motions. The feed may be stopped automatically at any predetermined depth by means of a dog on the adjustable stationary ring 39a coacting with a cam 39b on one of the levers 27. The feed may also be stopped at the limits of travel of the spindle by means of two dogs moving therewith which contact with a shaft engaging a lever 41a, Fig. 3, which is thus rocked to move the rod 51 and cam 31 axially to disengage the feed clutch 25.