Patent GB-518026-A (GB)
Title: An improved process and apparatus for grinding tools
IPC: B24B19/00
Filed: 1938-08-13
Abstract: 518,026. Grinding hand tools &c. STIFTUNG, A. P. Aug. 13, 1938, No. 23948. Convention date, Jan. 8, 1937. [Class 60] A method of grinding files, hammers, hatchets, hoes, knives and like tools on the lateral face of a grinding disc or ring 1 consists in positively moving, the tool, at least during traverse, in directions adapted to produce the desired shape of surface or edge, and maintaining the tool in continuous resilient contact with the grinding surface under a pressure which is determined by a manual or pedal control. The work holder 15, Figs. 1 and 2, is mounted on a table 14 which is movable laterally of the disc 1 by a universally-mounted handle 17, and on a slide 16 movable to and from the disc. The slide 16 is urged towards the disc so as to press the workpiece into contact therewith by a collar 27 which is slidable on a rod 22 and is caused to act through a spring 28 upon the slide by levers 25, 26 operated by a chain from a treadle. The table 14 runs on four track rollers 134, Fig. 3, and to permit its movement across the disc 1 in the path necessary to produce the desired form of the workpiece it is provided on its rear edge with a cam strip' 37 co-operating with conical rollers 38, 39 on the slide 16; spring pressed rollers 41, 42 on the slide engage the table in order to maintain the rollers 38, 39 and strip 37 in engagement. The two front track rollers 134 are pivotally mounted so as to permit steering of the table from a guide strip 31 which is mounted on the slide 16 for co-operation with a roller 33 connected by levers 34, 35 with the track rollers. A file 50 is held in the work-holder 15 in the position shown in Fig. 6, by a member 47 retained by a screw clamp 48, and in the position shown in Fig. 7 by a cranked lever 52 operated from a hand-lever 55, Fig. 2; the holder 15 is mounted on pivots 59 to permit angular adjustment. For grinding hammers with tapered ends, these are retained by a spring-pressed rod 74; Fig. 17, in a holder 72 which is mounted in a dovetail guide 71 in a head 66. The head 66 is adjustable about a horizontal axis on a block 64 which is adjustably mounted on a vertical axis 66a on the table 14; the adjustment of the head 66 about its horizontal axis is effected by stops 69 movable on a standard 70 and co-operating with an arm 68 on the head. When it is desired to round off the sides of a hammer, the block 64 may be oscillated about. its vertical axis 66a from an eccentric. A circular blade 82, Fig. 21 is ground while clamped in a mandrel which is rotatable in bearing 85 adjustably about a trunnion 86; this trunnion is carried by a block 83 adjustable about a vertical axis on the table 14. For grinding the circular blade with a curved bevel, the bearing 85 is oscillated about its trunnion 86 from an eccentric. For grinding the curved faces of axes or knives, the workholder 112, Figs. 29 and 30, is pivoted at 113 Tn a block 93 which is mounted for oscillation about a vertical pivot on the table 14. As the table 14 is moved on the slide 16 by the handle 17, the desired movements of the workpiece are obtained by (a) effecting movement of the block 93 on its pivot by cams 102, 103 acting on spring pressed rods 96, 97 connected with the block and (b) swinging the workholder about the axis 113 by the coaction of a spring-pressed roller 117 on the holder with a cam 118 arranged to be reciprocated in its guide 127 by crank-and-lever mechanism 128, 129, 130. The grinding disc 1, which is carried by a shaft 2, Figs. 1 and 2, driven by pulleys 4, 4a, is provided with a guard in the form of two relatively-adjustable parts 5, 6. A guard plate is also provided for protecting the mechanism underlying the table 14.