Patent GB-500617-A (GB)
Title: Spindle control for drilling and tapping machines
IPC: B23B45/14
Filed: 1937-08-09
Abstract: 500,617. Drilling and tapping machines. HEIDE, H. C. (Schauer, L. L., and McKEWEN, J. H.) Aug. 9, 1937, No. 21888. [Class 83 (iii)] A drilling and tapping machine has a tool spindle which is adapted for rotation and axial motion by mechanism controlled by a manual angularly movable device such that by its angular movement it serves positively to move the spindle axially in either direction and also to control the forward and reverse rotary movements thereof. The quill 24, in which the spindle 23 is rotatably mounted, is carried by a bracket 21 vertically adjustable on the pillar 20. An electric motor 28 drives the spindle through change speed gearing 26 and a drive is taken from this gearing, through further change speed gearing 27, to a feed shaft 29. A worm on this shaft rotates a worm wheel 31, Fig. 2, which is loose on a shaft 32 carrying a pinion engaging the quill. Two levers 36, Fig. 3, are pivoted at 37a to a sleeve 38 attached to the shaft 32 and have toothed ends engageable with an internally serrated ring 37 on the worm wheel 31. Springs 36a normally maintain the clutch disengaged but radial pins 40 in the sleeve 38 may be pressed outwards by a central axially slidable cam 41 to engage adjusting screws 39 on the levers to close the clutch. The cam 41 is moved axially by toothed segments 44 on the hand feed levers 45, and may also be moved to stop the feed at any predetermined point by dogs within a casing 46 which are driven in synchronism with the pinion shaft 32. The levers 45 are pivoted to a boss 47 which has a small free angular movement relatively to the shaft 32 as determined by rollers 51 on a sleeve 49, splined at 50 to the sleeve 38, engaging short helical slots in the boss 47. When the hand levers 45 are in either of the positions A or B, Fig. 2, radial plungers 48 in the boss 47 are pushed outwards by a projection on the cam 41 so as to press the sleeve 49 Against a shoulder on the sleeve 38 and prevent the sleeve 49 from moving axially, whereby the pinion shaft 32 is caused to move integrally with the levers, but when the latter are in position C, the pins 48 drop into a recess 53 in the cam 41 and the sleeve 49 is free to move axially. Rotation of the levers 45 in the feeding direction will then rotate the boss 47 on the shaft 32 and move the sleeve 49 axially until the rollers 52 engage the ends of the helical slots 51, and the levers 45 and shaft 32 then rotate together to feed the spindle 23. The axial movement of the sleeve 49 is utilized to start the motor 28 so as to rotate the spindle before its feed commences thus preventing a non-rotating tap from being forced against the work. For this purpose an annular groove 56 in the sleeve 49 engages a lever 54, Figs. 3 and 5 connected by a rod 58 to a switch D which controls selenoids F, R for rotating the motor in forward or reverse direction. When the sleeve 49 is locked against axial movement, the rod 58 rests in a depression 57 in the lever 54 and the switch D closes contacts Df for forward running of the motor. The spindle rotation may be reversed at any time by a hand lever 60 acting through levers 63, 64 on switches Ef, Er, which form a master control for the solenoids F, R.