GB888088A - Knife sharpener - Google Patents

Abstract

888,088. Sharpening knives. BURGESS VIBROCRAFTERS Inc. Nov. 2, 1959 [Nov. 3, 1958], No. 37161/59. Class 60. A knife-sharpener includes a tapered abrasive member, means for grinding a knife blade cutting edge into contact with the abrasive member, and means of reciprocating the member across the edge In the embodiment of Figs. 6 and 8 a conical abrasive member 6 is centrally disposed between two slots 4, 5, provided in a metal insert 3 within the upper portion 2 of the split moulded casing 1 of the sharpener, the knife-blade 12 being inserted in the slots successively to sharpen both sides of the cutting edge. A slotted partition wall 10, together with the outer edges of the slots, holds the blade at the proper angle against the cone. A spindle 8, to the top of which the abrasive member 6 is secured, is slidably and rotatably carried in nylon or like bearings 20, 21, domed lower end 18 of the spindle contacting the armature 16 of a vibration motor 13 comprising a core 13b and coil 13a supplied with alternating current. The armature 16 lifts the spindle and abrasive member against the action of a spring 19 so that during movement of the blade 12 through the slot the member is reciprocated at twice the supply frequency. A second spring 23, adjustable by a screw 25, provides a cushion for the downward movement of the armature 16. In the embodiment of Fig. 12 the motor 13 is inverted, having a stiff spring 46 opposed by a leaf-spring 47 to hold the spindle 8 in contact with the armature 14a. In a further modification, Fig. 10, a single knifelocating slot is used, a pair of abrasive members 38, disposed one on either side in staggered relation enabling both sides of the blade edge to be sharpened simultaneously. The members 38 are rotatably mounted on a yoke 41 secured to the top of a non-rotatable spindle 33 which is subjected to reciprocatory motion by a vibratory motor, as in the other embodiment. The embodiment of Figs. 6 and 8 may be provided with a non-rotatable wedge-shaped abrasive member 6 in place of the conical member shown. In a further modification rotation of the spindle instead of being effected by the to and fro movement of the blade, may be positively "driven" during upward movements of the armature 16 by an off-centre contact between a tang 50, Fig. 15, formed on the top surface of the armature.