GB1363955A - Machine for grinding shears - Google Patents

Abstract

1363955 Grinding D G BRAY 3 April 1973 [5 April 1972] 15783/72 Heading B3D A machine for grinding shears, such as garden. shears, large scissors, metal cutting shears and the like, comprises means 22 for holding a blade B to be ground in a generally stationary position, and means for supporting a rotatable grinding wheel 18 so that it can travel over. the blade along a path which follows the curvature of the blade. The machine has a chassis 1 having side walls 1b, 1c on which are secured cylindrical tracks 2a, 2b, the track 2a being inclined downwardly from the rear wall 1d of the chassis to the front, and the track 2b being inclined downwardly from the front to the rear wall 1d, the tracks being slightly curved and the front end of both tracks being at the same height. The tracks are engaged by the wheels 4 of a carriage 3 and a rod 5 extends from the carriage and passes through a universal bearing in the rear wall 1d. A pair of pillars 8 are mounted on the carriage and slidably receive a bush 9 which can be clamped in position by a screw 9a and is secured to a bracket 14 between the arms of which is mounted, with slight tiltable adjustment, a plate 7 carrying an electric motor 16. A shaft 17 of the motor extends through a slot 3b in the carriage 3 and carries the cup-shaped grinding wheel 18 in a guard 19. Movement of the bush 9 along the pillars 8 by a control knob 13 adjusts the peripheral edge 18a heightwise relative to the blade, and the degree of hollow grinding of the blade is determined by the amount of tilt of the plate 7. The blade B is held in a jig 21 having a support 23 provided with a guide 23a for the non-cutting edge of the blade. A clamp 22 grips the blade near its shank and consists of a pair of jaws 22a, 22b in arms 24 which can be moved about pivots 24a by screws 25. The clamp is frictionally mounted on a horizontal spigot and can be tilted from side-to-side by a handle 27, and the spigot is mounted in a block 28 pivotally mounted on a support 28b. The end of the spigot has a slot 29 engaged by a cam 30 on a rod 31 rotatable by a hand lever 32 to effect longitudinal tilting of the blade. The blade can therefore be tilted about longitudinal and transverse noses, and as the carriage moves, the wheel 18 hollow grinds the blades and, because of the inclination of the tracks, follows the longitudinal curvature and the twist or set of the blade.