GB653868A - Improvements in or relating to centreless grinders - Google Patents

Abstract

653,868. Centreless grinders. B.S.A. TOOLS, Ltd., and OGILVIE, W. July 24, 1948, No. 19838. [Class 60] In a centreless grinder of the in-feed type either the regulating wheel 1 or the grinding wheel 2 is controlled by an infeed cam 21 in such a manner that it is fed to the workpiece 5, is allowed to remain there for a predetermined period and is then withdrawn, the in-feed mechanism remaining inoperative until it is restarted by the operator. In the preferred embodiment the grinding wheel is controlled and is supported on a bracket 3 in screw-threaded engagement with a spring-loaded rod 7 provided with a hand wheel 9. The free end of this rod abuts a splined member 12 which is reciprocated by a spring-loaded lever 16 pivoted at 17 and oscillated by the in-feed cam 21. The latter is secured to a sleeve 22, Fig 2, freely mounted on a continuously driven shaft 24 carrying a freely mounted clutch element 30 and a fixedly mounted element 27. The element 30, which is spring-loaded towards engagement with the element 27, is connected with the sleeve 22 by a lug and slot drive 31 and has a face cam 35 to coact with an axially - displaceable, spring - loaded projection 36. A similar projection 60 has a tapered end engaging a slot in the periphery of the element 30. In operation the projection 36 is axially displaced to disengage it from the face cam by means of a linkage connected with the hand lever 49 so that the element 30 is pressed into engagement with the element 27 by its spring to rotate the cam 21 and dislodge the projection 60 from its slot. The hand lever is now released to allow the projection 36 to be displaced by its spring until it is in contact with the peripheral face above the cam 35 while the grinding wheel is actuated by the cam 21. When the highest point of the cam 35 passes the projection 36 the latter again bears on the cam face to cause the element 30 to be lifted out of engagement with the element 27 at the end of a complete revolution of the in-feed cam. Simultaneously with the separation of the clutch elements, the projection 60 re-engages its slot to hold the in-feed cam stationary until it is restarted by a further movement of the hand lever 49. A cam 65, movable with the in-feed cam, operates ejector mechanism (not shown) for the workpiece.