GB732103A - Improvements in or relating to abrasive feed device for lens grinding and like machines - Google Patents

Abstract

732,103. Grinding lenses. THOMAS, R. E. and RODWAY, Ltd., G. Dec. 21, 1951 [Dec. 21, 1950], No. 31132/50. Class 60. A device for feeding abrasive to a lens-grinding machine comprises a splash bowl 2 surrounding the work with clearance, a rotary container 8 for abrasive-carrying liquid located below an opening 4 in the bottom of the bowl, a feed pipe 17 which is fixed in the bowl with its upper end directed towards the work and its lower end opening within the container, and means for rotating the container at such a speed that abrasive is flung by centrifugal force against the inner periphery of the latter and caused to travel up the feed pipe on to the work. The bowl 2 is supported on brackets 6 on the machine frame in surrounding relation to the driving spindle 5 of the lap 1. The container 8, which is preferably of greater diameter than the opening 4 in the bowl, is mounted on the spindle 5 and partially closed by an annular lid 9; the inner edge of the lid has a rim 11 which is provided with drain slots 13 and a series of superposed and inwardly-directed baffles 12. The feed pipe 17 is carried by a bracket 16 which is secured by a detachable clip 14 to a transverse bracket 15 mounted on the inside of the bowl. The pipe 17 has a swan-neck outlet at its upper end to direct the abrasive on to the lap, and a nozzle 18 at its lower end located close to the inner periphery of the container. An openended scoop 19 of flattened tubular section is disposed on that portion of the feed pipe disposed in the container, to provide for an intimate mixing of the abrasive particles in the carrying liquid. A seal in the form of a rubber thimble 23 is fitted on the spindle 5 to prevent the leakage of abrasive-carrying liquid into the machine bearings. The container 8 is removable, after detaching the bowl 2 and lap 1, and so may readily be replaced by another containing a different grade of abrasive, when such is required. The change from a lap requiring a continuous feed of abrasive to a diamondbonded lap requiring only a continuous supply of water may be effected by replacing the container 8 and feed pipe 17 by a fixed trough which is fitted with its upper open side in register with the outlet from the bowl 2, and a circular thrower plate is secured to the lap spindle so as to rotate therewith; a downward flange on the outer edge of the thrower plate dips into the trough so that any water or detritus falling on to the plate is deflected outwardly and into the trough.