GB137915A - New or improved saw sharpening machine - Google Patents

Abstract

137,915. Collins, W. A., and Porter, L. B. Jan. 28, 1919. Saws, sharpening.-In a machine for sharpening saws, of the kind in which a grinding-disk is automatically moved to follow the protile of the saw teeth and mechanism is provided for moving the saw forward one or more teeth at each operation, the operations being so timed that the front or cutting-edge of a tooth is ground whilst the saw is stationary and the back of a tooth whilst the saw is being fed forward, means are provided for adjusting the angle or bevel of the front of the teeth and for adjustment of the movement of the saw and of the grinding-disk to adapt the machine to saws having teeth of different pitch. The saw 4 is secured by a spring-pressed conical clamp 51 to a block 3 adjustable on guides 2, and is sharpened by means of a grinding-disk 14 mounted in bearings in a bracket 11. This bracket is mounted to swivel about a pin 11<a> carried by a swivel pin 10, which is rotatably mounted in a bracket 9 provided with a slide 8 longitudinally movable on guides 7; adjustment of the grinding-disk about the pin 10 gives the required bevel cut or side clearance to the teeth. The guides 7 are carried by a bracket 5 angularly adjustable on a pivot 6 carried by the frame 1; such adjustment enables the cutting-angle of the front of the teeth to be varied. The grinding- disk is driven from a countershaft 15, which also drives, through worm gearing 20, 21 and a belt 25, a low-speed shaft 26<a> from which the reciprocating movement of the slide 8 and the feeding movement of the saw are derived. The slide 8 is reciprocated on the guides 7 by a profile cam 35, which engages a roller 36 adjustably mounted on the slide, and is carried by a slide-carriage 33 reciprocated in guides on the frame 1 by a rod 32 connected to a lever 31 mounted on a rocking shaft 30. This shaft is operated from the shaft 26<a> through an adjustable-throw crank 27 connected by a rod 28 to an oscillatory lever 29 carried by the shaft 30. The saw is fed forward by an adjustable-throw crank 41<a> on the rocking shaft connected, through an arm 40, with an adjustable pawl comprising a rod 39 adjustable longitudinally in the arm 40 by means of a screw and carrying the pawl tooth 38. The adjustablethrow cranks 27, 41<a> are constructed as shown in Fig. 6, and comprise a crank-pin 42 adjustable longitudinally of the crank-web by means of a screw 43. To prevent chattering, the saw is held rcsiliently against the face of a table 46 by a clamp 48. To produce opposite bevel cut on successive teeth. the saw is fed forward two teeth at a time, whereby every other tooth is given a similar cut; the grinding-disk is then re-set to give the opposite bevel. As described above, the machine is adapted to sharpen circular saws; it may also be adapted to sharpen hand-saws, bandsaws, &c. According to the Provisional Specification, the cam 35 may consist of a curved arm pivoted to the carriage at one end and having an adjusting-screw at the other end, and a fan may be provided for removing the metal particles.