Cutting by use of rotating axially moving tool – With work-engaging structure other than tool or tool-support – Work-gripping clamp
Reexamination Certificate
1999-10-25
2001-06-12
Tsai, Henry (Department: 3722)
Cutting by use of rotating axially moving tool
With work-engaging structure other than tool or tool-support
Work-gripping clamp
C408S11500B, C408S108000
Reexamination Certificate
active
06244794
ABSTRACT:
BACKGROUND OF THE INVENTION
1) Field of the Invention
This invention relates to doweling jigs in general, and more particularly, to a clamp-type doweling jig for locating in-line holes to be drilled in a wooden workpiece.
2) Description of the Prior Art
Doweling jigs for drilling corresponding holes in mating wooden workpieces, and thereby making possible the matching of these holes for the insertion of dowels and thus, the joining of the wooden workpieces in a desired engagement, are known. The engagements accommodate edge-to-edge, end-to-edge, edge-to-face, end-to-end and mitered joints.
Attempts have been made in the past to develop a better doweling jig. U.S. Pat. No. 5,407,307, dated Apr. 18 1995 and granted to Park for a “Doweling Jig” discloses a device having upper and lower clamping assemblies which move with respect to each other via a thrust screw assembly. Park's device has a number of shortcomings. First, two wooden workpieces are clamped together, one of which has previously been drilled, and in which dowels are installed through alignment slots, provided in the upper clamping assembly. As can be seen, there is a dependency on a previously drilled workpiece. Second, the device is provided, besides drill guides, with alignment slots and with guide slides between the upper and lower clamping assemblies. Thus, the jig described therein appears to be complicated, expensive to make and limited in use, since it has only two drill guides.
U.S. Pat. No. 4,421,442, dated Dec. 20, 1983 and granted to Lindblad for a “Doweling Jig” discloses a device which comprises two clamping jaw and drill guide assemblies, each of these assemblies having a clamping face and a drill guide which is immovable with respect to the clamping face. This device can be considered to have several disadvantages. In making use of the device in drilling corresponding pairs of dowel receiving holes in the two edges of two wooden workpieces, the latter must first be clamped together by a clamping fixture. Then, the doweling jig is clamped to the wooden workpieces, so that the drill guides are juxtaposed to the edges. After each two opposite dowel receiving holes are drilled, the device is unclamped, moved to the next opposite pair of dowel receiving holes and re-clamped.
As can be seen from the above patents, the disclosed devices are not easy to work with, require frequent set-ups and are thus, not quick to use, and also require measurements, due to the limited number of drill guides.
3) SUMMARY OF THE INVENTION
There is accordingly, a need for a doweling jig which overcomes the disadvantages of the prior art. It is further desirable to have a doweling jig provided with a number of holes with an accurately predetermined spacing from one another. Furthermore, to assure a precise coordination between the holes of the joint, use must be made of a common reference plane of the jig for each piece of the joint.
It is a first objective of this invention to provide a well engineered jig, the use of which is more efficient and faster than the doweling jigs known in the prior art or available on the market.
It is another object of the present invention to provide a novel doweling jig, the cost of which is within the practical, economic reach of even a home craftsman.
It is yet another objective of the present invention to provide a jig in which the only adjustment required is basically the adjustment of the distance between the screws which press against the wooden workpiece to be champed, when the jig is in use.
It is a further objective of the present invention to develop a jig which does not separate into numerous parts such as screws, nuts, bolts and other components, which could be easily lost, and difficult to replace, or could be replaced only by the time consuming process of writing to the manufacturer or supplier etc., if indeed they were available at all.
Broadly stated, the clamp-type doweling jig according to this invention, comprises a guide block to which are attached an alignment fixture at one side, and a clamping fixture at the opposite side. The guide block has the form of a parallelepied with top, bottom, lateral, front and back surfaces. In the guide block, several bores are aligned and extend through. The bores are perpendicularly disposed with respect to said top and bottom surfaces. The distance between one end of the guide block, which is delimited by the front surface, and the first of the several bores is equal to the distance between the other end of the guide block, which is delimited by the back surface and the last of the several bores. In each of the several bores, a drill guide is firmly affixed, so that its lower end is substantially flush with the bottom surface of the guide block. On both sides of the guide block, two threaded studs for attaching the alignment and clamping fixtures, respectively, are provided. Each threaded stud has a portion for assembling, with minimal clearance, the above fixtures, and a threaded portion for a knob with a threaded hole.
The alignment fixture incorporates an attachment plate, for fastening, to one of the lateral surfaces of the guide block, and an alignment jaw. The latter extends from the attachment plate downwards and inwards, towards the center of the guide block. Two through holes are provided in the attachment plate, and are so chosen, that the latter is moveable for assembling the alignment fixture with minimal clearance. The alignment jaw incorporates a foot-protrusion which extends partially under the bottom surface, at right angle relative to the attachment plate. The foot-protrusion has an upper face which mates with the bottom surface and runs the length of it, and a reference plane which is parallel to the lateral surfaces and perpendicular to the bottom surface. The clamping fixture includes a joining plate and a clamp plate which forms a single component. The former and latter plates are situated in parallel planes. The joining plate mates with a corresponding lateral surface, while the clamp plate is retracted with respect to the guide block and has two threaded holes, in which screws are inserted for function as clamps.
In one aspect of the invention, the clamping fixture is attached, instead of to the guide block, to the alignment fixture, specifically to the abutting face of it.
In another aspect of the present invention, a removable insert is positioned between the attachment plate and the guide block, or between the attachment plate and the knobs with threaded holes.
Optionally, on both external surfaces of the foot-protrusion, which surfaces are coplanar with the front and back surfaces, respectively, a flip stop element, which can be rotated in either an operative or inoperative position, is provided.
REFERENCES:
patent: 1161479 (1915-11-01), Kelley
patent: 2260784 (1941-10-01), Morton
patent: 2535450 (1950-12-01), O'Malley
patent: 4952101 (1990-08-01), Coombs
patent: 5466098 (1995-11-01), Juang
patent: 6116826 (2000-09-01), Benway
Kaufman Frederick
Tsai Henry
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