Cutting by use of rotating axially moving tool – With work-engaging structure other than tool or tool-support – Work-gripping clamp
Reexamination Certificate
2000-03-02
2001-07-03
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
Reexamination Certificate
active
06254320
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a fixture for drilling pocket holes in a workpiece.
BACKGROUND OF THE INVENTION
The use of fixtures for location and guidance of a drill bit to drill holes in a workpiece, such as a piece of wood, for pocket joints is well known. A pocket hole is one that is made at an angle in a piece of wood and a wood screw is inserted into the hole to join the workpiece to another wood piece. The screw is recessed in the hole and is not exposed.
U.S. Pat. No. 4,955,766 discloses the combination of a drill bit with a stop collar and a fixture used for making pocket holes at an angle to a surface of the workpiece. The fixture has an L-shaped base with one leg serving as a guide portion for the workpiece and the other as a portion to hold a clamping device, shown as an over-center clamp. An angled channel having a stop flange at its upper end is provided on the guide portion leg. The drill bit is inserted into the channel and drills a hole at an angle in the workpiece up to the point where the stop collar engages the flange. The fixture of this patent is somewhat complicated in that the over-center clamp is required as well as the drill bit with a stop collar. Also, in this patent the workpiece is held against a flat surface and the wood chips produced during the drilling can only escape up through the channel. This has a tendency to clog the drill bit and to adversely affect its efficiency.
U.S. Pat. 1,128,970 discloses a fixture for drilling holes for dowels, the holes being drilled transverse to the workpiece. The workpiece is held in a base by a clamp and a carriage containing bushings for passage of a drill bit into the workpiece is moveable over the base to place the hole of a over a proper location on the workpiece. While the clamp of this patent is relatively simple as compared to an over-center clamp, the fixture does not show drilling of an angled pocket hole.
BRIEF DESCRIPTION OF THE INVENTION
The present invention relates to an improved and relatively simple fixture for making pocket holes in a workpiece. In accordance with the invention the fixture is U-shaped. One of the legs of the U shaped fixture is the guide leg, against the interior of which the surface of the workpiece to be drilled rests. This guide leg has an angled channel to accept a drill bit, preferably of the stepped type. The fixture leg opposite to the guide leg has a threaded hole through which passes a screw threaded clamp. A base leg connects the guide and clamp legs to complete the U.
In the use of the fixture, one surface of the workpiece rests on the base leg and another against the interior surface of the guide leg. The threaded clamp is moved from the clamp leg toward the surface of the workpiece facing the clamp leg to engage it and thereby hold the workpiece securely while the drill is advanced through the angled guide channel to make the hole in the workpiece.
In a preferred embodiment of the invention the interior surface of the guide leg has several spaced ribs preferably extending transverse to the leg. The workpiece surface engages the ribs. The exit opening of the drill bit channel is between the ribs on the guide leg. The space between the ribs provides a passage for the wood chips to exit from the drill bit as the hole is being drilled in the workpiece. The base leg has a recess on its interior surface located where the drill bit exits the workpiece through the drilled angled hole. This helps keep the end of the drill bit from contacting the base leg and being damaged.
The fixture accepts a conventional stepped drill bit in the guide channel and no stop collar for the drill bit and flange for the base wall is required. The fixture is simple in construction and efficient in operation permitting precise drilling of a pocket hole in a workpiece.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a novel fixture for drilling pocket holes in a workpiece.
A further object is to provide a U-shaped fixture for forming pocket holes in a workpiece in which a fixture guide leg against which the workpiece rests has an angled guide channel through which the drill bit passes and the opposing leg holds a threaded clamp which is advanced to clamp the workpiece against the guide leg.
Yet another object is to provide a U-shaped fixture for forming pocket joints in a workpiece with the interior of the leg against which the workpiece rests has a pair of spaced ribs between which there is the exit of an angled guide channel through which the drill bit passes to enter the workpiece serving as a passage for the wood chips produced during the drilling.
A further object is to provide a U-shaped fixture for drilling pocket holes in which the base leg on which a surface of the workpiece rests has a recess at the point where the drill bit exits the angled hole made in the workpiece.
REFERENCES:
patent: 917488 (1909-04-01), Roberts
patent: 3708237 (1973-01-01), Kraus
patent: 4093394 (1978-06-01), Adams
patent: 4145160 (1979-03-01), Wiggins
patent: 4955766 (1990-09-01), Sommerfeld
patent: 5063982 (1991-11-01), Durney
patent: 5466098 (1995-11-01), Juang
patent: 5676500 (1997-10-01), Sommerfeld
patent: 5791835 (1998-08-01), Chiang et al.
patent: 5800099 (1998-09-01), Cooper
Deaton Richard H.
Weinstein Burton
Coplein Gordon D.
Simp'l Products, Inc
Tsai Henry
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