GB464332A - Improvements relating to machine tools more particularly thread-grinding machines - Google Patents

Abstract

464,332. Grinding screw-threads &c. LINDNER, H. Oct. 11, 1935, No. 28143. Convention date, Aug. 2. [Class 60] In a machine for grinding screw-threads, for example on taps &c., wherein the carrier for the work or for the tool is adapted to be rocked about an axis parallel to the axis of rotation of the work both for feed and adjustment, the shaft about which the rocking movement takes place serves also as a longitudinal guide for the carrier during its traverse. The machine comprises a frame 1 having a support 2 for the profiled grinding wheel S which is driven from an electric motor 4 mounted on a separate pedestal and the work is supported on a slide 13 by means of a tailstock 16 and a centre 14 on a spindle in a gear box 19, the drive being effected by a belt from an electric motor. The slide 13 is supported by a segmental member in two parts 26, 26a, adjustable, to suit the helix angle of the thread, in guides on a member 27 on the frame 1 by means of a pinion 76 in the member 26 and a rack 77 on the member 27, the member 26 being locked in adjusted position by bolts. The slide is rockable on, and slidably supported by two shafts 28, 29, the shaft 28 being secured to a guide 26b on the member 26a by screws 30 and the slide being supported on the shaft by guides 31. The shaft 29 is secured to the slide 13 by screws 32, and the slide 13 is supported at the front by a rod 33 guided by a shoe 34 on a guide 35. The work spindle is driven by a pulley 38 mounted on a pin 37 carried in ball bearings in the member 26a and carries a worm 41 driving a worm-wheel 42 mounted in the shaft 28, which is made in two parts. The wheel 42 is slidably keyed to a shaft 45 mounted at its other end in ball bearings in the shaft 29 and carries a worm 47 driving a worm-wheel 48 which drives, through gearing, the work spindle. The slide is traversed by a screw 49 driven through gearing from the wheel 48, the screw engaging the slide through a collar and engaging a nut 51 in guides in the slide and held between stop surfaces on the member 26. The support 33 is carried by a lever 55, and is adjusted up or down to produce small adjustments of the position of the work by a screw 57 rotated through worm gearing 59 by a graduated hand wheel 60. The lever 55 is guided laterally by guide surfaces 61 at one end, and by a pin 62 at the other end, and abuts against the slide at points 63, 64, the point 63 being supported by a slide 65 on a lever 66 pivoted on the box 19 and carrying a roller 68, engaging a cam 69, which effects the feed of the slide 13, the cam being driven at such a speed as to move the work in and out for each flute of a tap ; the extent of the rocking movement is adjusted by adjustment of the slide along the lever 66. The work may be moved rapidly towards or from the grinding wheel by means of a handle 70 mounted on a pin 71 eccentrically mounted on slide 13 and contacting with the support point 64 by means of a ball bearing 72 ; the shoe 34 slides on an adjustable member on the guide 35, which is angularly adjustable about a pivot 35b, for treating conical work. In a modification, the pivot for the rocking motion is formed by two short cylindrical members on the slide and a counter-guide on the frame ; the shaft elements may be part cylindrical and the guide of prismatic section.