500,616. Radial drilling and tapping machines. HEIDE, H. C. (Schauer, L. L.) Aug. 9, 1937, No. 21886. [Class 83 (iii)] In a radial drilling and tapping machine, independently operable controls are provided for reversing the power-driven spindle rotation including dominant, sub-ordinate and auxiliary controls, and means are provided for automatically subordinating the effective action of the two last mentioned controls to the action of the dominant control unless and until the dominant control has been set in an ineffective position. A pillar 16 on the base 15 carries a rotatable sleeve 17, on which the radial arm 18 is vertically slidable, the arm being partly balanced by an electric motor 30. A shaft 32 in the arm is driven from the motor through a clutch or change gearing 31 and operates the spindle drive and feed and the arm elevating gear. The spindle 29 is driven by bevel gears on the shaft 32 and a change speed drive giving nine speeds and the feed is obtained from a gear in this train and a further change speed gear which drives a shaft 37. Fig. 3, carrying a worm engaging a worm wheel 39, freely rotatable on a shaft 40 carrying a pinion 42 meshing with the quill 44. A clutch 41 for connecting the worm wheel to the shaft is actuated by levers 51 rocked by radial pins 50 when a central rod 48 carrying a cam 49 is moved axially by toothed segments 46 on hand feed levers 45. An automatic stop for the feed is provided by a stationary dog 52 engaging one of the levers 45. The feed is disengaged at each end of the spindle traverse, to prevent the pinion 42 from overrunning the rack teeth on the quill, by means of a cam 56 and a gear 64 which is driven through back gears 61 and bevel gears 58 from the feed shaft 40. The cam engages a pin 54 slidable in the drill head 19 and rocks a lever 53 which moves the rod 48 to disengage the clutch. The cam 56 rotates through slightly less than one revolution whilst the quill makes a full stroke. After the clutch 41 has been disengaged by the cam 56, the spindle 29 may be fed a small distance further by hand. until the cam engages a conical sleeve 55 which is fixed concentrically with the pin 54 to form a positive stop. Hand feed of the spindle 29 may also be effected by a hand wheel 65, Fig. 1, a lever 66 and a handle 67. The hand wheel 65 is secured to the lower end of the shaft 37 and effects a fine feed, as for facing &c. operations, whilst the lever 66 gives a coarser feed through a shaft 62, Fig. 6, which carries the back gears engaging the gear 64, Fig. 3, connected to the shaft 40. A spring pressed dog 70 in the lever 66 is adapted to engage teeth on the shaft 62 when released by a latch lever 68 and a rod 68c, the latch being normally maintained in the disengaged position by a fixed stop pin 68d. With the dog 70 engaged, movement of the lever 66 through 90‹ feeds the spindle 29 through about three inches, and the lever may then be indexed to new positions on the shaft 62 for further feed, this arrangement enabling the lever to.be used in its most effective position, irrespective, of the spindle position. The handle 67 carries a roller 71, Fig. 3, engaging a short helical slot in the shaft 62 so that rotation of the handle will first move it axially and will then feed the spindle 29 manually. The axial movement is utilized to start the motor 30 for driving the spindle in the appropriate direction during tapping operations through a pair of alternative relay switches Cf, Cr controlling the motor switch RS, Fig. 11, through solenoids F, R. The operator is thus able to engage the rotating tap with the work by rotating the handle 67, after which the tap feeds itself until the operator rotates the handle 67 in the reverse direction, thus reversing rotation of the tap and feeding it upwards. A further handle similar to 67 may be secured to the shaft 62 for actuating the feed without affecting the spindle rotation, and for swinging the radial arm 18 about the pillar 16. The arm is clamped to the sleeve 17 by means of a hollow screw 91, Fig. 9, engaging a nut 94 and provided with clutch teeth engageablo with teeth on a hand lever 90, which is pivoted at 100 in a slot in a bracket 93 on the arm. A detent 99 holds the screw 91 in the clamped or undamped position after it has been released from the lever 90. A rod 101 passing through the screw 91 is pivoted to the lever 90 and has teeth 107 engageable with splines in the boss-of a lever 103 connected by a link 104 to a lever 105 which actuates a clutch 82 connecting the arm shaft 32 to a worm 84 which rotates a nut 88 held axially on the arm and mounted on a screw 89 fixed to the sleeve 17. Movement of the lever 90 about the pivot 100 to engage the screw 91 for operating the clamp moves the clutch to the inoperative position and vice versa, and a gated slot 106 in the bracket 93 prevents this in or out movement unless the lever 90 has been moved to the unclamped position. The teeth 107 on the rod 101 also engage a switch 108 for starting the motor 30 in either direction so that with the lever 90 disengaged from the screw 91, the latter being unclamped, rotation of the lever will close the clutch 82 and start the motor in the appropriate direction to raise or lower the arm according to the direction of rotation of the lever 90. A constantly acting friction brake 82a stops rotation of the worm 84 as soon as the clutch has been thrown out. The rod 101 may also be rocked to stop the motor and throw the clutch at the upper or lower limits of travel of the arm by means of a lever 109 thereon engaging a slot in a vertical rod 110 which abuts against the top or bottom of the sleeve 17 at the limits of travel. The motor 30 may also be controlled from a hand lever 111, Fig. 3, on the head, which rocks an arm 113, to actuate a switch-operating rod 114. A detent locates the lever 113 in'its positions. The switches A, B, C, Fig. 11, for controlling the switch RS which starts, stops and reverses the motor 30, and which are actuated by the levers 90 and 111 and handle 67 respectively, are interlocked so when anyone is in use, the others are prevented from controlling the motor. Thus the supply by wire 4 to switch C passes through a bridge Bs which is only closed when the lever 111 is in neutral position and the wire 4 is also broken automatically by a switch D to cut out switches B, C when switch A is being used. The switch D is operated by a plunger 121, Fig. 9, engaging a recess in the lever 103 to close the switch when the lever is in position to open the clutch 82, but which is forced out of the recess to open switch D when the clutch 82 is closed. In a modification the switch C is arranged in series with switch B. slides and carriages.-The drill head 19, Fig. 1, which may be traversed along the arm 18 by means of a hand wheel 24 on the head rotating a pinion engaging a rack 27 embedded in the arm, runs on rollers resting on a hardened steel strip 22 forming one of the square guides 23 on the arm. Clamping is effected by a plate on the upper guide 23 and a handle 28.