Patent GB-500484-A (GB)
Title: Improvements in and relating to drilling and tapping machines
IPC: B23B39/12
Filed: 1937-08-09
Abstract: 500,484. Drilling and tapping machines. HEIDE, H. C. (Schauer, L. L.) Aug. 9, 1937, No. 21887. [Class 83 (iii)] A drilling and tapping machine has a tool spindle adapted to be rotated by a prime mover and moved axially to and from the work by a manually operable device which is co-ordinated with control means for starting or reversing the spindle rotation so that the rotation will be started in the appropriate direction before the axial movement commences. A pillar 16 on the base 15 carries a rotatable sleeve 17 on which a radial arm 18 is vertically slidable. A shaft 22 in the arm is driven directly from an electric motor 21 and operates the spindle drive and feed, and the arm elevating gear. The spindle 20 is driven by bevel gears on the shalt 22 and a changespeed drive within the head 19, and a drilling feed is obtained from a gear in this train and a further change-speed gear which drives u shaft 29, Fig. 4. carrying a worm engaging a worm-wheel 31 freely rotatable on a shaft 32 carrying a pinion 34 meshing with the quill 35. A clutch 33 for connecting the worm-wheel to the shaft is actuated by levers 37 rocked by radial pins 39 when a central rod 40 carrying a cam 42 is moved axially by toothed segments 44 on hand feed levers 43. An automatic stop for the feed is provided by a stationary dog 46, on an adjustable depth gauge dial 45, engaging one of the levers 43. The feed is disengaged at opposite ends of a spindle traverse, to prevent the pinion 34 from overrunning the rack teeth on the quill, by means of a cam 55 on a gear 54 which is driven through back gears 51 from the feed shaft 32. The cam engages a pin 57 slidable in the drill-head 19 and rocks a lever 58 which moves the rod 40 to disengage the clutch. The cam 55 maintains an invariable position with respect to the quill. After the clutch 33 has been disengaged by the cam 55, the spindle 20 may be fed a, small distance further by hand, until the cam engages a conical sleeve 56, which is fixed concentrically with the pin 57 to form a positive stop. Hand feed of the spindle 20 may also be effected by a lever 59 or a handle 64. The lever 59 gives a slow feed through a shaft 63, Fig. 3, which carries the back gears 51 engaging the gear 54 connected to the shaft 32. The lever 59 is held out of action when not required by a latch mechanism 60, but which may be released to allow a plunger 61 to engage a toothed wheel 62 on the shaft 63. The handle 64 carries a roller 65 engaging a short helical slot 66 in the shaft 63 so that rotation of the handle will first move it axially and will then feed the spindle 20 manually. The axial movement is utilized to start the motor 21 for driving the spindle in the appropriate direction during tapping operations through a pair of alternative relay switches f<1>, r<1>, Figs. 4 and 9, controlling the motor switch RS, through solenoids F, R. The operator is thus able to engage the tap with the work by rotating the handle 64, after which the tap feeds itself until the operator rotates the handle in the reverse direction. thus reversing rotation of the tap and feeding it upwards. The arm 18 is clamped to the sleeve 17 by means of a hollow screw 81, Fig., 6, engaging a nut 82 and provided with clutch teeth 80 engageable with teeth on a hand lever 78 which is pivoted at 79 in a slot in a bracket 79<1> on the arm. A rod 83 passing through the screw 81 is pivoted to the fever 78 and has teeth 87 engageable with splines in the boss of a lever 84 connected by a link 85 to a lever 86 which actuates a clutch 71 connecting the arm shaft 22 to a worm 70 which rotates a nut 76 held axially on the arm and mounted on a screw 77 fixed to the sleeve 17. Movement of the lever 78 about the pivot 79 to engage the screw 81 for operating the clamp moves the clutch to the inoperative position and vice versa, and a gated slot 78<1> in the bracket 79' prevents this in or out movement unless the lever has been moved to the unclamped position. A cam on the lever 84 engages a switch c, d for starting the motor 21 in either direction so that with the lever 78 disengaged from the screw 81, the being unclamped, rotation of the lever will close the clutch 71 and start the motor in the appropriate direction to raise or lower the arm according to the direction of rotation of the fever 78. A constantly acting friction brake 72 stops rotation of the worm 70 as soon as the clutch has been thrown out. The rod 83 may also be rocked to stop the motor and throw out the clutch at the upper or lower limits of travel of the arm by means of a lever 89 thereon engaging a slot in a vertical rod 90 which abuts against stops at the top and bottom of the sleeve-17 at the limits of travel. The motor 21 may also be controlled from a hand lever 94, Figs. 3 and 4, on the head 19, which rocks an arm 95 to actuate a switch-operating rod 96 engaging the opposite sides r, f of the switch B. The switches A, B, C, Fig. 9. for controlling the switch RS which starts, stops and reverses the motor 21, and which are actuated by the levers 78, 94 and handle 64 respectively, are interlocked so that when any one is in use the others are prevented from controlling the motor. Thus the supply wire 9 to switch C passes through a bridge 8 which is only closed when the lever 94 is in the neutral position, and the wire 7 is also broken automatically by a switch D to cut out switches B and C when the switch A is being used. The switch D is operated by a plunder 100. Fig. 6, engaging a recess 101 in the lever 84 to close the switch when the lever is in position to open the clutch 71, but which is forced out of the recess to open switch D when the clutch 71 is closed. In a modification the switch (' is arranged in series with the switch B. The heart 19 is traversed along the arm 18 by means of a hand wheel 99 thereon.