Patent GB-1424927-A (GB)
Title: Grinding machines
IPC: B24B25/00
Filed: 1973-11-24
Abstract: 1424927 Sharpening cutting tools AUTOMATIC GRINDING MACHINE & ENG CO Ltd 24 Nov 1973 54645/73 Heading B3D A grinding machine for sharpening woodworking tools comprises a base 10, and a grinding wheel assembly 102, Fig. 1, having a grinding wheel 118, a workpiece support 28, the plane of rotation of the grinding wheel relative to the workpiece support being capable of pivotal adjustment about first and second axes. A pillar 12 is upstanding from the base and, on one side, has a mount 14 for a cylinder 26 carrying the workpiece support 28, and, on its other side, has a mount 18 for a cylinder on a bracket 72 carrying the grinding wheel assembly 102. The cylinder 26 is vertically adjustable in the mount 14 by a screw 30 and is clamped in position by a pinch clamp 24. A workpiece table 28 is carried by the cylinder and has a T-slot 32 along which a screw 34 is adjustable, the screw having a spring-urged conical member 38 for engaging the bore of a circular saw blade 36 placed on the table. A U-shaped member 44 extends from the work-table 28 and has a friction pad 46, Fig. 2, for engaging the lower surface of the blade. The upper arm of the member has a collar 48 into which is screwed a vertical shaft 49, the lower end of which has a friction pad 50 engaging the upper surface of the blade, a knob 52 adjusting the shaft and pad 50. A cylindrical member 54 is rotatable on the shaft 49 and is urged upwardly into contact with a sleeve 56. A handle 58 extends from the member 54 for moving the member downwardly to engage a peg 62 on a projection 60 with the space between a pair of teeth of the blade so that, on rotation of the member 54 by the handle, the blade is indexed, sliding between the friction pads, by a distance determined by engagement of an adjustable stop on a radial arm 64, the stop contacting a plate (not shown) and engagement of pins 68, 70 on the member 54 and U-shaped member 44, respectively. The bracket 72 supporting the grinding assembly 102 is pivotable about a vertical axis in the mount 18 to a position determined by a scale 74 and can be held in position by a pinch clamp 24. An upper portion 76 of the bracket supports a wheel carrier 80 for adjustment about a horizontal axis to a position determined by a scale 82 and can be held in position by a clamp 78. The carrier 80 has a cylindrical portion 84 clamped to a sleeve 86 through which extends a feed screw 94 fixed at one end to a cup 96. A key 98 on the cup engages a slot 100 in sleeve 86, and a boss 106 of a base-plate 104 of the grinding wheel assembly is slidable on the sleeve 86 and pressed by a spring 108 against a bearing plate 112. The other end of the feed screw engages an adjusting knob 90, rotation of which causes axial movement of the feed screw and hence the sleeve 106 carrying the grinding wheel assembly. The spring eliminates backlash between the feed screw and knob. The grinding wheel assembly consists of the grinding wheel 118 which is belt driven from a reversible electric motor 114 on the plate 104 which has a handle 120 for pivoting the assembly 102 through a distance determined by an adjustable stop 124 about the axis of the sleeve 86 to feed the grinding wheel in an arcuate path tangential to the blade. A spring 122 counterbalances the weight of the assembly. When the side faces of the teeth of the blade are to be ground, the grinding wheel assembly is adjusted about the axis of the portion 76 of the bracket 72 so that the grinding wheel is parallel to the blade. For sharpening the front face of the teeth, the blade is mounted on a bracket (126, Fig. 4, not shown) and indexed about a vertical axis, the. grinding wheel being in a horizontal plane. A V-shaped holder (136, Fig. 5, not shown) may be mounted on the workpiece support for holding a twist drill during sharpening, and a further holder (142, Figs. 6 and 7, not shown) may be provided for holding a router cutter. Fig. 8 shows a planar blade 144 which is to be sharpened by the wheel 118 and is secured by clamps 146 to a carriage 148 slidable on a fixture 150 mounted on the support 28. An extension may be mounted on the support for use in sharpening large diameter saw blades.