CA2278170A1

CA2278170A1 - Miter keeper

Info

Publication number: CA2278170A1
Application number: CA 2278170
Authority: CA
Inventors: James M. Stewart
Original assignee: Individual
Current assignee: Individual
Priority date: 1999-07-16
Filing date: 1999-07-16
Publication date: 2001-01-16

Abstract

In the joining of 2 pieces of wood using 45 degree miter joints.
this invention enables a standard spring clamp to provide equal pressure to each side of the joint at 90 degrees to the faces being joined. It also simultaneously traps the 2 pieces to be joined at 90 degrees to each other, thereby eliminating the need for further adjustment.

Description

LIST OF DRAWINGS
In drawings which illustrate embodiments of the invention, Figure 1. is a top view of a standard spring clamp and is intended to show how such a common clamp without this invention will not remain on the pieces to be joined.
Figure 2. is a top view and elevation of the device called "MITER KEEPER" which will enable the standard clamp to perform the function of clamping the two pieces of material together by providing pressure on each side and at 90 degrees to the miter faces to be joined.
Figure 3. Illustrates the "MITER KEEPER" device in use.

3.
SPECIFICATION
This invention relates to the direct clamping of 2 pieces of material ( wood, metal or plastic ) using 45 degree miter joints.
It is common in devices used for clamping a miter joint, that they do not provide clamping pressure at 90 degrees to the faces being joined. Rather, they merely hold the 2 pieces of material while the 2 miter faces are touching each other but not under direct pressure. These current devices also allow slippage of the material or distortion of the miter joint until proper alignment of the 2 pieces of material is finally adjusted but even then, clamping pressure is not applied where it is needed. i.e. At 90 degrees to the faces being joined.
A standard spring clamp cannot grip the material due to the fact that its own pressure squeezes it right off the material.
(See Figure 1.) This invention utilises the effect of clamp slippage and the problem becomes a benefit.
I have found that a retaining rod with a square block placed between the inside of the joint and the back of the clamp not only prevents the clamp from slipping off but also provides additional clamping pressure to the inside of the 2 pieces being joined and at the same time, squares the material. Now that the clamp is prevented from slipping, the clamp jaws are able to concentrate their pressure equally on each side and at 90 degrees to the surfaces being joined.(See Figure 2.) The Miter Keeper can be used by placing the squaring block(See Figure 2.) on the inside of the material and the other end of the retaining rod behind the notch formed by the handles of the clamp or the end of the retaining rod can be inserted where the clamp spring is retained by a pin.
The clamp pin can be removed and the retaining rod when inserted will perform the same function as the pin. (i.e. Holding the pieces of the clamp together).

Claims

1. A manually operable tool for clamping miter joints comprising a retaining rod and an adjustable squaring block.

2. A tool as defined in Claim 1, in which the squaring block is threaded to accept the retaining rod which can then be shortened or lengthened to alter the distance between the squaring block and the right angle on the retaining rod providing a range of thicknesses of material to be held between the jaws of the clamp.

3. A tool as defined in Claim 1, in which the squaring block provides more than one threaded hole to accept the retaining rod so that the inside height of the material to be clamped has a range of bearing surface against the squaring block on the inside of the assembled joint.

4. A tool as defined in Claim 1, which enables the jaws of the clamp to provide equal pressure at right angles to the miter faces to be clamped and equidistant from the inside edge of the joint to the outside edge of the joint.

5. A tool as defined in Claim 1, where the squaring block automatically holds the material at right angles to each other and provides an instant visual check of the integrity of the 90 degree angle between the 2 pieces of material.

9.

6. A tool as defined in Claim 1, which enables the operator to view the entire length of the outside edge of the assembled miter joint to inspect the integrity of the miter joint.