Tool grinding jig
View Patent ↗A hand tool grinding jig is described for use in co-operation with a grinding wheel. The jig has a tool clamp for clamping a hand tool and a leg is pivotally connected to the clamp to allow the angle between the leg and the clamp to be adjusted. An end of the leg remote from the clamp provides a pivot point for engagement in a pivot receiver of a pivot support member that is located adjacent to the grinding wheel. The pivot receiver is disposed so that, when a tool is in the tool clamp and the pivot point is provided in the pivot receiver, the pivotal axis between the leg and the clamp is further from the grinding wheel than the pivot receiver.
1. A hand tool grinding jig for use in co-operation with grinding apparatus having a rotatable grinding wheel, the jig including in combination:
a tool clamp for clamping a tool,
a leg pivotally connected to the clamp about a leg pivotal axis, said leg is angularly adjustable relative to the clamp and said leg has a ball or point-type pivot point element at an end thereof remote from the clamp,
at least one pivot support for location of said pivot point element adjacent to the grinding apparatus and having a pivot receiver adapted to receive said pivot point element, and
said pivot support is adjustable so that the position of the pivot receiver may be adjusted relative to the face of the grinding wheel to allow the tool to be provided at a required angle relative to the grinding wheel face, said adjustment ranging from at least a first, forward position for said pivot receiver lying below said grinding wheel and between about the outer face of said grinding wheel and the center axis of rotation of said grinding wheel to a second, back position that is outboard of the leg-to-clamp pivot distance from the face of the grinding wheel.
2. A jig as claimed in claim 1 wherein the pivot receiver is disposed so that when a tool is disposed in the tool clamp and the pivot point is disposed in the pivot receiver the leg pivotal axis is further from the grinding wheel than the pivot receiver.
3. A jig as claimed in claim 1 wherein the pivot receiver is disposed so that when a tool is disposed in the tool clamp and the pivot point is disposed in the pivot receiver the leg pivotal axis is closer to the grinding wheel than the pivot receiver.
4. A jig as claimed in claim 1 wherein two pivot receivers are provided, each pivot receiver being provided in a plane of the grinding wheel.
5. A jig as claimed in claim 1 wherein the clamp includes a clamping block which is moveable relative to two intersecting walls to clamp the tool between internal surfaces of the walls and the clamping block.
6. A jig as claimed in claim 1 wherein the clamp includes a clamping block which is moveable relative to two intersecting walls to clamp the tool between internal surfaces of the walls and the clamping block, and the walls each having an aperture therein to receive a side of the clamping block.
7. A jig as claimed in claim 6 wherein the clamping block may be moved substantially adjacent to the point of intersection between the walls.
8. A jig as claimed in claim 6 wherein said clamping block extends through said apertures in said intersecting walls.
9. A jig as claimed in claim 1 wherein the pivot support comprises a first part adapted to be affixed adjacent to the grinding apparatus and a second part which carries the pivot receivers, the second part being adjustably movable relative to the first part.
10. A method of shaping a hand tool comprising the steps of:
clamping the tool in a clamp having a leg pivotally connected about a leg pivotal axis to the clamp and angularly adjustable relative to the clamp, the leg having a ball- or point-type pivot point element at an end thereof remote from the clamp,
providing at least one pivot point element receiver closely associated with a grinding wheel positioned in at least a first, forward portion lying below said grinding wheel and between about the outer face of said grinding wheel and the center axis of rotation of said grinding wheel
adjusting the position of the pivot receiver and the angle of said leg relative to the grinding wheel to allow the tool to be provided at a required angle relative to the face of the grinding wheel, and
moving the tool about the pivot point element to shape the tool, said ball- or point-type pivot point permitting said tool to move around a portion of a plurality of axes.
11. A method as claimed in claim 10 including the step of adjusting the pivot receiver so that when a tool is disposed in the tool clamp and the pivot point is disposed in the pivot receiver the leg pivotal axis is further from the grinding wheel than the pivot receiver.
12. A method as claimed in claim 10 including the step of adjusting the pivot receiver so that when a tool is disposed in the tool clamp and the pivot point is disposed in the pivot receiver the leg pivotal axis is closer to the grinding wheel than the pivot receiver.
13. A method as claimed in claim 11 including the step of moving the tool about the pivot point such that a nose of the tool may be placed in contact with the grinding wheel at a substantially constant angle.
14. A method as claimed in claim 12 including the step of moving the tool about the pivot point such that a nose of the tool may be placed in contact the grinding wheel and the angle between the grinding wheel and the tool nose decreases as the tool is rotated from the tool nose to a side of the tool.