Abrasive tool making process – material – or composition – Impregnating or coating an abrasive tool
Patent
1992-01-08
1994-04-12
Kisliuk, Bruce M.
Abrasive tool making process, material, or composition
Impregnating or coating an abrasive tool
51 46, 51115, 51 91R, 51218R, 51216R, B24B 4106
Patent
active
053014731
DESCRIPTION:
BRIEF SUMMARY
This invention relates to grinding apparatus, particularly though not exclusively for hand tools and blades therefor, e.g. chisels, screwdrivers and plane blades, and more specifically relates to a tool holding jig for a grinding machine.
BACKGROUND OF THE INVENTION
Hand tools such as chisels are conventionally given a good cutting edge by hand-honing on an oil-stone. However from time to time more radical grinding is necessary e.g. to remove nicks in the sharpened edge and to re-establish the conventional 25.degree. angle between the two faces at the edge. This can be done by using a surface grinder with a cup-shaped grinding wheel and a carriage for holding the hand tool which is reciprocated to and fro across the axial annular working face of the grinding wheel by a chain e.g. for a distance of two feet. Such surface grinders are expensive and non-portable (they have cast iron beds) and they can take a long time to remove perhaps 1-2 thou (25 to 50 micrometers) from the sharpened edge due to the length of travel. Alternatively a portable grinder with a standard disc grinding wheel can also be used but such a grinder is not provided with a carriage and the operator has to be skilled if he is to provide a straight sharpened edge in the minimum time without overheating the steel so that its temper is lost.
There is therefore a need for a relatively inexpensive adapter apparatus for a bench grinder which will permit safe, rapid, accurate, automatic grinding of a tool or blade near where it is being used rather than in an engineering workshop.
A tool holding jig is known from GB 378162 for use when grinding chisels and plane blades. This jig comprises a pair of linkages arranged in a parallelogram configuration by each having one end universally pivotally mounted on a base of a grinding machine and by each having near its other end a uniaxially pivotal connection to a tool holding member onto which a tool can be clamped. In use, the tool is rocked to and fro across the grindstone manually using handles at said other ends of the linkages. A problem with this known jig is that the angle to which the tool is ground is dependent on the position in which the tool is clamped to the holding member, and thus care needs to be taken when mounting the tool in the holding member to ensure the correct angle will be achieved. A further problem with this known jig is that the type of pivotal connections which are shown and described will enable the parallelogram configuration to skew so that the difficulty will be caused when attempting to grind a straight square edge.
SUMMARY OF THE INVENTION
The present invention is characterised in that parallelogram linkages are mounted on the grinding machine by respective substantially parallel swivel rods for uniaxial pivoting about the axes of the rods. Thus, the angle of the plane of the parallelogram structure is predetermined. Furthermore, a parallelogram structure which is more resistant to skewing out of its own plane can be provided.
Preferably, the plane in which the tip of the tool rocks is arranged to be inclined, for example at an angle of 2.degree..+-.1.degree., to the end face of the grinding wheel so that the tip is at its most forward position when it is in the central region of its rocking motion. Thus when the edge being sharpened is in its central position with respect to the grinding face it is pressed with a maximum pressure against this face and when it moves away from this central position, the pressure decreases. This compensates for the tendency to form a convex edge which arises because of the increased grinding rate when only part of the length of the edge is being pressed against the grinding face.
While hand rocking of the holder is envisaged, it is preferred that the apparatus comprises drive means connecting a shaft driving the grinding wheel to the holder e.g. via speed reduction means and a crank or eccentric. The speed reduction means desirably comprises an initial belt drive followed by a gear train. If the belt drive permits for example a spe
REFERENCES:
patent: 1440386 (1923-01-01), Hawes
patent: 3440772 (1969-04-01), Wright
patent: 3881889 (1975-05-01), Hunkeler
patent: 4736544 (1988-04-01), Greenquist
Kisliuk Bruce M.
Morgan Eileen P.
LandOfFree
Grinding apparatus comprising a tool holding jig does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Grinding apparatus comprising a tool holding jig, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Grinding apparatus comprising a tool holding jig will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2090790