Static structures (e.g. – buildings) – Openwork; e.g. – truss – trellis – grille – screen – frame – or... – Three-dimensional space-defining
Reexamination Certificate
1999-12-06
2001-12-11
Friedman, Carl D. (Department: 3635)
Static structures (e.g., buildings)
Openwork; e.g., truss, trellis, grille, screen, frame, or...
Three-dimensional space-defining
C052S702000, C052S704000, C052S749100, C403S230000, C256S065080
Reexamination Certificate
active
06327830
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a structural member with aligning means for a mating part, and more particularly to a rigid body formed of a hard material having at least one hole therein for receiving a mating part formed of a material such as wood which is softer than the material of the body. The hole includes alignment means for properly aligning the mating part relative to the body.
The invention is especially adapted for use with pieces of wood such as conventional “2×4 lumber”, wherein the lumber has a rectangular cross-section. The rigid body may comprise a component of shelving utilizing 2×4 lumber such as disclosed in U.S. Design patent application Ser. No. 29/103,042, the disclosure of which is incorporated herein by reference. The rigid body may also comprise a component of a convertible bench and table top assembly as disclosed in U.S. Pat. No. 4,913,488, the disclosure of which is incorporated herein by reference. The invention can be employed in other types of construction wherein it is desired to interconnect a rigid body with a mating part which is formed of material which is softer than that of the rigid body.
The original design of the rigid body for use with shelving is disclosed in U.S. Design patent application Ser. No. 29/091,633, the disclosure of which is incorporated herein by reference. In this original design, rectangular holes were provided which were oversized for receiving pieces of lumber therein which were secured in place by screws. It is common knowledge that lumber, while milled to a specific dimensional size, does not maintain its dimensions and shape when exposed to the environment, resulting in the lumber swelling, bowing, twisting and cupping. The oversized rectangular holes were intended to provide clearance for the changes in size and shape of the lumber which occurs in the normal course of events, without introducing stress into the rigid body. The rigid body and piece of lumber were assembled by the use of a single screw extending through one long side of a hole and a single screw extending through one short side of a hole, effectively pulling the lumber into contact with the sides of the hole forming one corner of the hole, which is similar to the arrangement with other commonly available brackets and the like.
This original design proved to be unacceptable. Since the rigid body may be, for example, either a metallic casting or a molded plastic, it is necessary to provide relief angles or “draft” for the large rectangular openings so that the molded or cast body can be effectively released from the mold. Such relief angles make it difficult to properly align the lumber so that it extends perpendicular to the body as is desired. Furthermore, the average amount of clearance between most lumber and the sides of the holes afforded movement and/or deflection of the non-contacting sides of the lumber, which resulted in twisting and misalignment of the rigid body relative to the lumber. Therefore, the assembled rigid bodies and lumber are not sufficiently stable. This is a common problem with these types of assemblies, and manufacturers often suggest the use of additional components for cross-bracing the assemblies.
SUMMARY OF THE INVENTION
The present invention incorporates one or more holes which are slightly larger than the nominal dimensions of a piece of lumber to accept the variations in the dimensions of the lumber, and the holes in the rigid body are provided with means for positively properly aligning a piece of lumber relative to the body so that the lumber will be perpendicular to opposite sides of the body.
It is apparent that the invention may be employed with a rigid body having a single hole therein, or a body having a multiplicity of holes therein. In either case, each hole is generally rectangular in cross-section as is the mating part such as a piece of 2×4 lumber. The hole has two long sides and two short sides, with a longitudinal axis extending through the hole. Three ribs are provided which project into the hole and extend generally parallel with the axis of the hole. A first rib is formed at the midpoint of the one of the long sides of the hole; and a second rib is formed at the midpoint of the other one of the long sides of the hole. A third rib is formed at the midpoint of one of the short sides of the hole. In a modified form of the invention, a fourth rib is formed at the midpoint of said one of the short sides of the hole.
The ribs on the rigid body are molded without draft to extend parallel with the longitudinal axis of the hole and provide three points of contact with the mating part, which, by design, automatically squares the lumber relative to the body. The body and mating part are fastened to one another by one or more screws. In the case of swollen or twisted lumber, the ribs contact and/or penetrate the softer lumber at only the three points of contact, and therefore the rigid body is more easily moved or repositioned relative to a piece of lumber without jamming within the hole such as would occur if the hole were a close fitting hole without ribs.
REFERENCES:
patent: 2406078 (1946-08-01), Hushower
patent: 2817423 (1957-12-01), Dye et al.
patent: 2931129 (1960-04-01), Boniface
patent: 4355725 (1982-10-01), Humphrey
patent: 4474299 (1984-10-01), Andrews
patent: 4758111 (1988-07-01), Vitta
patent: 5560588 (1996-10-01), Hilliard
Hecht Thomas R.
Livingston Howard F.
Dykema Gossett PLLC
Friedman Carl D.
Glessner Brian E.
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