Patent GB-430986-A (GB)
Title: Automatic nut and like tapping or screw cutting machine
IPC: B23G1/20
Filed: 1935-01-01
Abstract: 430,986. Tapping nuts ; screwing. SMITH, C. B., 7, Alexandra Road, Edgbaston, Birmingham. Jan. 1, 1935, No. 33702/33. [Class 83 (iii)] An automatic nut &c. tapping or screw-cutting machine, of the kind having a tap or die at each end of the spindle and a clutch for reversing the rotation of the spindle together with the reversal of axial movement thereof, has means for imparting an axial movement to the clutch before each screw - cutting operation, independently of the axial movement of the spindle. The spindle 8 carries a tap t at each end and is rotatable and slidable in bushes 9 mounted in supports 10. A sleeve 11, Fig. 6, is splined to the spindle 8 and has splined thereon clutch parts 12 provided with friction bands 14 adapted to engage alternately with clutch parts 15 secured to sprockets 16 which are driven in opposite directions by chains 35, Fig. 2, shafts 32, 33 and bevel gears 34, the shaft 33 being rotated through fast and loose pulleys 37. The sprockets 16 are rotatable on the bushes 9 and abut against thrust bearings 17. Spring plungers 18, Fig. 6, in the clutch parts 15 normally engage flanges 11<a> on the sleeve 11 when the respective clutch is closed, but if the clutch tends to slip, the plungers enter slots 19 in the flange 11<a> to render the drive positive. The sleeve 11 is moved axially to reverse the drive by means of a yoke 20 carrying rollers 21 which act on flanges 11<b>, springs 13 being provided between the flanges and the clutch parts 12. The yoke 20 is formed as a slide movable on a guide 22, Fig. 2, by means of a vertical lever 23, link 24 and a lever 25 carrying two pins 26 which straddle a cam 27. Spur gears 29 and worm gearing 31 drive the cam from the shaft 32. The spindle 8 is given the axial tapping feed by means of a screw thread on the spindle or on a sleeve 38 secured thereto co-operating with nut segments 39 carried by two levers 40 pivoted on a shaft located below the spindle and normally drawn together by a spring 41. In operation, the spindle advances towards the left in Fig. 2 to tap a nut n and unscrew the tap t' from the nut at the right hand end of the machine. On completion of the tapping operation, the spindle 8 is moved bodily to the right through a link 43 connected to the cam-operated lever 25 and oscillating a shaft 45 carrying a lever 46 acting on one of the levers 40. This withdraws the tapped nut from its holding means 48 to the position shown in Fig. 2 between cheeks 55 so that on reversal of the direction of rotation of the spindle by the cam 27, the tapped nut will be unscrewed from the tap t and will drop into a discharge shoot 57<a>. Simultaneously, the tap t' will enter a nut n'. The axial movement of the levers 40 by the link 43 brings the levers against a collar on their supporting shaft so that on reversal of rotation of the spindle, the nut segments 39 are held stationary to feed the taps for screwing and unscrewing. Should the movements of the machine become slightly out of phase the nut segments will encounter bevelled surfaces 38<b> on the sleeve 38 to separate them against the spring 41 and prevent further axial movement of the spindle 8 until its rotation has been reversed, the threads on the tap being arranged to permit a few rotations without axial movement. Any number of spindles 8 may be arranged in parallel relation in one machine and may be moved axially by a spider engaging collars &c. on the spindles and connected to a master lead screw. Blanks, transferring.-Nut blanks are supplied from a hopper, (not shown), to a vertical shoot 58, the lowermost blank being transferred by a pusher 48 to a position in front of the tap. The pusher is operated by a lever 50, a spring 51 and a cam on a shaft 53 driven through bevel gears from the gear 29. The tapped nuts drop into a discharge shoot 57<a>. Screwing.-Screwing dies may be substituted for the taps t, t<1>. Lubricating cutting tools and work.-A sprocket 36, Fig. 2, on the shaft 32 drives a suds pump through a chain.