Patent GB-727769-A (GB)
Title: Improvements in or relating to sharpening apparatus
Inventor: JOHNSON HAROLD FREDERICK
IPC: B24B3/36
Filed: 1953-04-01
Abstract: 727,769. Sharpening cutting-tools. MACHINE SHOP EQUIPMENT, Ltd. Feb. 5, 1954 [April 1, 1953], No. 9044/53. Class 60. Apparatus for sharpening cutting-tools, particularly surgical cutting-tools such as -microtome knives and the like, comprises a pair of cup-shaped grinding wheels 14, 14 disposed in spaced relationship and angularly offset with respect to each other and means whereby a blade or tool to be sharpened may be moved back and forth across the cupped face of either of said wheels while being maintained in fixed angular relationship with respect thereto. A microtome knife 10 is held by clamping devices 31, 31 slidable axially along a fixed guide-bar 11 so that the knife may be reciprocated between two housing elements 12, 13, each housing a grinding wheel 14. The wheels are driven through belts 19, 20 from a common power source such as an electric motor 18; alternatively each wheel may be driven from an independent power source. Means for varying the spacing of the wheels without varying the angle of offset comprise a rod 21 having threaded portions 22, 23 of opposite hand; portion 22 co-operates with a threaded member 24 associated with one wheel support 25 slidable on guides 26; portion 23 co-operates with a threaded member 27 associated with the second wheel support 28 slidable on guides 29. Shaft 21 is operated by handle 30; means may be provided for looking the wheels in selected position of adjustment. A visual indication of the wheel spacing is provided by a pointer 60 on one wheel support co-operating with a fixed scale 61. Adjustable stops 32, 33 are associated with the guide-bar 11 to limit the extent of movement of the clamping devices 31, 31. Each clamping device comprises a carrier body 34 having an aperture 35 to accommodate the guide-bar 11; the carrier body is formed centrally with an upstanding lug 36, the upper surface 37 of which is concave to form a seating for the back of the .blade. A shaft 38 journalled in the lug 36 has threaded portions 39, 40 of opposite hand engaging clamp members 41, 41, each of which carries a pivoted jaw 42. To facilitate adjustment of the clamp members on assembly, one of the members incorporates a compensating bush 43 in threaded engagement with a threaded portion of shaft 38, the bush fitting a bore in the clamp member and being keyed thereto after setting-up. The carrier body 34 has grooves 44, 45 in its underside to accommodate balls or rollers supported in or on rigid guides 46, angularly movable, by handle 49, about stud shafts 47, 48 journalled in the machine frame. Means such as a spring- loaded plunger 50 is provided for positively locking the guides in either angular position of adjustment. The clamping devices 31, 31 may be coupled together longitudinally. The wheels 14, 14 are made of glass and fluid lapping medium, e.g. an alumina abrasive suspended in water, is supplied continuously to the wheels from a reservoir by a pump 51 driven by belt 52 from the motor 18 which drives the grinding- wheels. A control valve 53 is operated by a knob 54. The system may be emptied by a drain cock 55. A trough 56 is provided. To dress the grinding-wheels, an attachment is fitted into one of the clamping devices, the attachment comprising a carrier portion 57 to which is secured an abrasive head 58. Guards 59 for the grinding wheels are provided. The reciprocation and periodic angular movements of the clamping devices may be effected mechanically, the motive power being derived from the motor driving the grinding wheels or from a separate source.