Woodworking – Wood bending clamp
Reexamination Certificate
2000-09-14
2001-12-18
Bray, W. Donald (Department: 3725)
Woodworking
Wood bending clamp
C144S256100, C144S259000
Reexamination Certificate
active
06330894
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the construction of curved wooden structures with bent wooden boards. More particularly this invention relates to a wood bending jig which can be adapted to bend boards on any selected radius and which can accommodate even complex curves. The jig has particularly advantageous application in the construction of custom spiral staircases.
BACKGROUND OF THE INVENTION
Arches and curves provide a beauty and eye appeal in architectural structures which is not provided by square lines. However, despite their inherent beauty, the labor intensive and time consuming task of constructing rounded structures severely limits their use. When a round staircase is built a large cylindrical wall form which will circumscribe the staircase is first fabricated. The stringers are then wrapped around this form, and the stair boards are fitted into the form with angles bolted to the wall form. Finally the wall form is removed from the stinger and stair boards; and the stair boards are fastened directly to the stringer. Considerable time and materials are utilized fabricating the cylindrical wall form and considerable time is consumed disassembling, then reassembling the stringers and stair boards after the cylindrical wall form has been removed. There is a need for a simpler, faster and less expensive method of constructing a rounded stair case.
OBJECTS OF THE INVENTION
It is an object of this invention to disclose a wood bending jig which facilitates the construction of rounded stair cases. A wood bending jig which can be used to fabricate both inner and outer stair stringers, stair railings, stair skirts, rounded beams for round openings through floors, as well as eliptical beams for openings through pitched roofs. It is an object of this invention to disclose a wood bending jig which eliminates the step of constructing a cylindrical form to build the rounded stair cases in and around. It is an object of this invention to disclose a wood bending jig which will allow stringers to be bent with and stair boards to be attached to the bent stringers directly and without the necessity of disassembling and then reassembling the stair case. It is yet a further object of this invention to disclose a wood bending jig which is adjustable to accommodate varying radiuses and pitches of inclination of varying stair cases. It is a final object of this invention to disclose a wood bending jig which can accommodate even complex curves, curves which have varying radiuses along their periphery.
One aspect of this invention provides for a jig for bending a wooden board, above a supporting surface comprising: a trunk; and, multiple arms each arm having an inner end portion releasably attached to the trunk and an outer arm portion adapted to removably attach the wooden board thereto. When the wooden board is attached to the outer end portions of the arms the wooden board will have bent to conform to a curve defined by the end portions of the arms as it extends up, and around the trunk.
In a preferred aspect the invention in the above jig, the trunk and radial arms comprise cylindrical tubes. The arm portions which attach to the trunk comprise split cylinders which may be lockably squeezed over the trunk with a bolt. Each arm comprises a second inner cylindrical tube which closely and lockingly slides within a first outer cylindrical tube so that the outer end portion of the arm may be locked at a selected radius from the trunk so that the jig may be used to bend boards at varying radiuses.
Various other objects, advantages and features of this invention will become apparent to those skilled in the art from the following description in conjunction with the accompanying drawings.
REFERENCES:
patent: 927975 (1909-07-01), Kaufman et al.
patent: 4688612 (1987-08-01), Kessel et al.
patent: 5199475 (1993-04-01), Koeder
patent: 5203948 (1993-04-01), Suska
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