GB190412777A - Improvements in Apparatus for Sharpening Rock-drilling Machine Bits, Hand Drills, and the like. - Google Patents

Abstract

12,777. Kirsten, J. A. G. June 6. Rock drills.-In a machine for cutting off the fractured portion of the webs of rock drills of cruciform section, four cutters D, Fig. 1, working in slots c<1> are made to approach at the same time. The two horizontal cutters and the lower vertical one are operated through levers by an eccentric b<1> on the shaft B. The eccentric causes the plate E to move up and down in its guides, and the lower vertical cutter is adjustably attached to the projection e<6> of the plate by means of a wedge e<9>. The horizontal cutters are operated by levers f<5> pivoted to a plate F and connected at their lower ends f<7> by adjustable connecting-rods f to the plate E. The top vertical cutter is connected to a rod G operated by an eccentric b<2>. The flywheel carries a wiper to remove the portion of the bit which is severed or partially severed by the cutters. A machine, Figs. 10 and 11, for working out the worn-down corners of the bits and for forming the cutting-edges has four dies running in slots, the upper die being stationary, and the other three operated from an eccentric actuated by a handlever by mechanism similar to that described in reference to Fig. 1. A ram 62, running in guides 61, operates a " dolly 65 with a convex face and made with four radial grooves. The convex face works out the centre portions of the bit to the tips, and the grooves form the cutting-edges. A block 81 supported on plates 75 runs along the table 2 and serves to support the end of the bit while being operated upon. It is moved by a pinion running on a rack formed by pins, and is held in position by a lever operating a pawl on a ratchet-wheel.