Cutting by use of rotating axially moving tool – With work-engaging structure other than tool or tool-support – Adjustable – tool-guiding jig
Reexamination Certificate
2000-03-28
2001-06-12
Howell, Daniel W. (Department: 3722)
Cutting by use of rotating axially moving tool
With work-engaging structure other than tool or tool-support
Adjustable, tool-guiding jig
C408S097000
Reexamination Certificate
active
06244795
ABSTRACT:
The present invention relates to a dowelling jig which is used to guide a drill to form bores in respective work pieces in accurately corresponding positions so that a dowel or bolts can be inserted into the corresponding bores, and joint surfaces of the work pieces bought together to form an accurate joint.
Complex and expensive workshop tooling is available to aid the drilling of bores for receiving dowels in joints which are extensively used in woodworking. One system has been devised to use biscuit-shaped connection elements instead of cylindrical dowels but in each case, complex and expensive machinery is used and intended for workshop use. Furthermore, simple marking guides have been available to assist the drilling of bores for dowels but because considerable accuracy is required for the formation of a successful joint it is important that significant skill, care and attention is used if successful and neat joints are to be formed.
Examples of commonly required dowelling joints are in right angle joints between posts and rails in furniture, mitre joints in picture frames and joints between the edges of boards which are formed together, for example, to provide a table top. This latter application can be considered particularly demanding because a series of spaced dowels are required and any misalignment of a single bore will create problems. It is highly desirable that the joint when formed is neat and essentially no further working upon the surfaces of the joint is required. For example, with moulded products such as picture frames and the like, it is most important that the joint faces meet precisely and neatly and require no more than light sanding.
Although the invention is not confined to embodiments when the dowelling jig is hand held, an embodiment which facilitates the hand holding of the work piece and the jig is highly desirable. This permits a high degree of portability and use in a simple workshop or on a site where a construction work is taking place. There is a need for a device which can be used without high levels of skill or particular attention and yet the drilling process can be effected very speedily. Thus at least preferred embodiments of the invention lend themselves to significant practical advantage both to professionals who can operate easily and speedily with a simple hand held electric drill or even an unskilled handyman.
According to the present invention, there is provided a dowelling jig for guiding a drill for preparing aligned bores in corresponding joint faces of two work pieces which are to be joined using dowels each work piece having a side face at right angles to its joint face, the jig comprising;
(a) a spacer plate having opposite sides against which the side faces of the work pieces are to be placed and held,
(b) first and second drill guide arms adapted to be secured to the spacer plate and to extend away therefrom in opposite directions, each arm providing a surface against which a joint surface of one of the work pieces is to abut,
(c) at least one through-bore in each of the drill guide arms for guiding a drill bit at right angles into the work piece, each through-bore having an axial length sufficient for guiding a hand held drill to drill a work piece bore substantially at right angles to the joint surface, and
(d) a through-bore on one arm corresponding in position to a through-bore on the other arm such that the bores align when the joint faces of the work piece are brought into abutment.
Preferably the dowelling jigs are T-shaped in end view, the leg of the T acting as the spacer plate and also having through-bores to facilitate the boring of further drill holes in the side face of the work piece, the dowelling jig further comprising a stop plate which is detachably mounted to one end of the T-shaped structure and when in position acts as a stop against which an end face of the work piece is inserted.
In a preferred embodiment of the invention the drill guide arms are adapted to be fixed and clamped to the respective sides of the spacer plate by spaced screws which extend through the arms and the spacer plate, the jig further including a screw threaded clamp member into which the free ends of each fixing screw is threadably inserted to clamp the components together, the dowelling jig further including spacer elements which are optionally selected for insertion between one or both of the drill guide arms and the spacer plate to vary the spacing from the spacer plate of the respective through-bores, whereby the device is adapted to accommodate workplace configurations of different thickness and dowel positions relative to the work piece side face, each of the drill guide arms having at least first and second sets of through bores, one set being of a first diameter and the other set being the second diameter for guiding drill bits of different diameter, the arms being reversible so that either set of through bores is closer to the spacer plate.
A preferred embodiment of the invention is one in which each drill guide arm is of a substantial thickness and of relatively hard material resistant to being enlarged inside by unintended contact with a tip of a drill, the thickness of each drill guide arm being preferably 15 to 20 mm and being of hardened metal.
Preferably the entire unit is adapted to be hand held so that the respective work pieces can simply be held in the desired drilling position with one hand an electric drill used to drill the bores. In this embodiment the length of the dowelling jig is advantageously of the order of 10 cm.
The drilling jig can be supplied as a kit of parts adapted to be assembled by the user into the desired form. The kit usefully can include at least one secondary spacer of the same thickness as the spacer plate and this is adapted to be inserted between the work pieces at a remote location and preferably a simple hand clamp is used so that the work pieces over an extended length are spaced apart by the desired amount. At least after the drilling of the first set of dowel holes, the optional end can be pivoted away or unscrewed from its position whereby the dowelling jig can be simply slid along the elongated work pieces. This is most useful when, for example, joining together the is long boards.
REFERENCES:
patent: 2470038 (1949-05-01), Long
patent: 2836087 (1958-05-01), Ehresmann
patent: 2949798 (1960-08-01), Berta, Jr.
patent: 4153384 (1979-05-01), Isaken
patent: 4443138 (1984-04-01), BUtera
patent: 4602898 (1986-07-01), Brown et al.
patent: 4730959 (1988-03-01), Aerni et al.
patent: 5209614 (1993-05-01), Matthews
patent: 5409329 (1995-04-01), Juang
patent: 5466098 (1995-11-01), Juang
patent: 685381 (1998-01-01), None
patent: 666 130 (1995-08-01), None
patent: 2 116 084 (1983-09-01), None
patent: 97/13608 (1997-04-01), None
Fenelon Rosemarje
Foley & Lardner
Howell Daniel W.
LandOfFree
Dowel 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 Dowel jig, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Dowel jig will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2442136