GB644744A - Improvements connected with apparatus for the crush forming of grinding wheels - Google Patents

Abstract

644,744. Profiling grinding-wheels. COVE NTRY GAUGE & TOOL CO., Ltd., JELLIS, M., and DARBY, W. Aug. 26; 1948, No. 22508. [Class 60] Ribbed grinding wheels are crush-profiled by an apparatus in which a rotatable member turns a lead screw 4 to feed the crushing roller 1 slowly, and axially displaces the lead screw by cam means or the like to feed the crushing roller rapidly. The rotatable member is in the form of an annularly-shaped face cam 11 provided with an arm 12 in spring- loaded engagement with a profile cam 14. The cam 11 is connected with a flanged member 7 secured to the lead screw by means of freely-mounted plungers 19, springs 20 serving to hold the member 7 in contact with the plungers. The motor for driving the cam 14 has a recess in its shaft to operate a switch which breaks the motor circuit after each complete revolution. The upper portion of the lead screw is in splined and slidable engagement with a hand-wheel 23 and a ratchet wheel 21 which co-operates with a pawl 22 secured to the cam 11, while the screwed portion of the lead screw engages a nut 6 freely mounted in the slide 2 and biassed upwardly by springs 26 against a stop plate 25. When this nut is downwardly displaced relatively to the slide it operates a switch for the grinding-wheel motor by means of a plunger and a lever. In operation, the grinding-wheel is initially crushed by manually operating the slide 2, after which the crushing roller is withdrawn by an amount corresponding to the lift of the cam 11. A scale 34 indicates the extent of withdrawal. The cam 14 is now set in rotation to turn the cam 11. This causes an axial advance of the lead screw and the crushing roller through the plungers 19, the'resistance to further movement of the crushing roller caused by its contact with the grinding wheel displacing the nut 6 to start the grinding wheel motors: Further rotation of the cam 11 due to a rise on the cam 14 causes the'lead screw to be rotated through the pawl and ratchet mechanism to feed the crushing roller into the grinding wheel. A dwell on the cam 14 now allows crushing to continue for a predetermined period after which a sharp fall produces reverse rotation of the cam 11 so that the pawl rides over the ratchet teeth and the cam 11 allows the lead screw to be retracted by the springs 26, the movement of the nut 6 switching off the grinding wheel motor. A shroud 39 provided with a small aperture may be used to enclose the ratchet wheel, the position of the aperture determining the point at which the pawl becomes operative and hence the feed of the crushing roller. The shroud is locked in adjusted position by a screw 41.