Abrading – Work holder – Clamp
Reexamination Certificate
1999-08-02
2001-03-27
Eley, Timothy V. (Department: 3723)
Abrading
Work holder
Clamp
C451S386000, C451S391000
Reexamination Certificate
active
06206772
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is in the field of hand tools and more specifically relates to a hand tool for holding a disc while the circumference of the disc is being ground to produce a disc having a desired diameter.
2. The Prior Art
One way of producing a disc of a desired diameter is as follows. A number of disc-shaped blanks are punched from a sheet or plate of the chosen material. These blanks do not have the desired final diameter due to the fact that a punch of the right size may not be commercially available, and due to the lack of precision inherent in the punching process. In addition, the punched blanks may have burrs or irregular edges. The tool of the present invention is used for holding a punched blank while the circumferential edge of the blank is ground, to bring it to the desired diameter and to eliminate the burrs and irregularities.
In U.S. Pat. No. 163,683 issued May 25, 1875 to Norton, there is shown a clamp for use in grinding watch crystals. The crystal is held between elastic-faced grippers each of which rotates about an axis that is perpendicular to a jaw of the clamp. The jaws open and close by pivoting about a pin.
In U.S. Pat. No. 2,551,648 issued May 8, 1951, to Suben, there is shown a tool for use in beveling a lens. As in Norton's tool, the jaws are connected by a pivot. Also, a spring is used to urge the jaws closed. Each jaw terminates in a rotating gripper.
The tools of Norton and of Suben are designed for working with discs of a particular thickness. Because the jaws are connected by a pivot, as the jaws are opened to accommodate a thicker disc, the axes of the rotating grippers cannot remain in a single straight line. The elastic facing of the grippers can accommodate only relatively small variations of disc thickness. Larger variations in disc thickness disrupt the gripping action and may cause the disc to become dislodged.
With this problem in mind, the present inventor set out to design a disc grinder capable of being used with discs having a wide range of thicknesses.
SUMMARY OF THE INVENTION
The main object of the present invention is to provide a disc grinder that can, without adjustment, be used to grind discs that have a wide range of thicknesses.
In accordance with the present invention, the jaws open and close along a pair of parallel guide rods that assure that the axes of rotation of the grippers remain colinear as the jaws are opened and closed.
In a preferred embodiment, the jaws are biased to an open position, and the user squeezes the jaws closed by overcoming the biasing force.
In a alternative embodiment, a threaded member is rotated to draw the jaws together.
In all embodiments, the axes of the rotating grippers remain colinear as the jaws are opened and closed, thereby permitting the tool of the present invention to be used for grinding discs of various thicknesses.
The novel features which are believed to be characteristic of the invention, both as to organization and method of operation, together with further objects and advantages thereof will be better understood from the following description considered in connection with the accompanying drawings in which a preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for the purpose of illustration and a description only and are not intended as a definition of the limits of the invention.
REFERENCES:
patent: 163683 (1875-05-01), Norton
patent: 1445908 (1923-02-01), Perkins
patent: 2551648 (1951-05-01), Suben
patent: 3934316 (1976-01-01), Driscoll
patent: 5018711 (1991-05-01), Johnson
patent: 5860197 (1999-01-01), Fox
Eley Timothy V.
McKown Daniel C.
Nguyen Dung Van
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