Patent GB-761681-A (GB)
Title: A machine for sharpening or polishing knives, scissors and like objects having a cutting edge
Inventor: VOR GIJSBERT DE
IPC: B24B3/52
Filed: 1954-03-26
Abstract: 761,681. Sharpening or polishing knives. scissors &c. BERG, A. J. DE VOR-VAN DEN. March 26, 1954, No. 8986/54. Class 60 A machine for sharpening or polishing knives, scissors and like objects having a cutting edge comprises two oppositely rotatable grinding or polishing discs disposed in a common plane and mounted in permanently spaced relationship in stationary supports, supporting means for the blades of the knives, scissors and the like to be sharpened or polished on either of said discs, the supporting means being adjustable substantially in a vertical direction in the plane containing the discs to accommodate variations in the cross-sectional shape and/or area of the blade and mechanism located on one side of the plane and operable to effect the adjustment of the supporting means. Grinding discs 4, 7 are driven in opposite directions by a motor 1 through a belt 5 and a crossed belt 8. The base plate 2 has a stand 9 carrying a beam 10 on which carriages 12, 13 are oppositely adjustable by means of screw spindle 11 with left and right hand threads. The carriages are provided with discs 14, 15 rotatable about pivots by worms 18, 19 on a shaft 16 having a hand wheel 17. The discs carry guide sleeves 20, 21 in which members 22, 23 are longitudinally slidable but not rotatable. The members 22, 23 are movable up and down by a handle 24 hinged to the base plate 2 in journals 26, 27 and having a roller 25 supporting the members 22, 23 in opposition to spring pressure. For pointed knives or knives having faces of varying width, blade supports 30, 31 are mounted by screws 28, 29 on the members 22, 23. The supports each have two cutting edge supports 32, 33 and 34, 35 which extend on either side of the grinding disc and which limit the movement of the blade towards the disc; at the rear of the supports, two supports 36, 37 and 38, 39 for the back edge of a blade are provided. In operation, the knife is drawn through the machine by one hand while the other hand operates the handle 24. When a large number of knives having faces that are uniform over the entire length of the blade are to be rapidly ground, the blade support 30, 31 are replaced by a blade supporting bridge 40, Fig. 4, secured to the members 22, 23 by screws 28, 29. The bridge 40 has a slot through which the grinding discs may pass, the two marginal edges of the slot extending parallel to the plane containing the discs and disposed one on either side thereof, each providing a supporting surface common to both discs for the blade; these supporting surfaces may alternatively be provided on two elongated rollers extending parallel to said plane and arranged one on either side thereof.. To obtain faces of constant width the handle 24 is secured against movement by clamping screws 41, 42. For knives having very large faces or curved shapes, a carriage 43, Fig. 5. is arranged on the bridge 40 and is movable thereon by a handwheel 44 and string 45. On the carriage is secured a blade support 46 having four pins 47 at its corners the blade support bearing on four compresion springs 45 arrange about the pins. On either side of the discs supports 49 for the back edge of the blade are provided, two on each side. The cutting edge supports are formed by two longitudinal rollers 50, 51. Dust may be confined by a hood and exhausted by a suction fan driven by the motor 1. The grinding discs may be replaced by polishing discs, and scisors and like objects having a cutting edge may be treated.