Fire escape – ladder – or scaffold – Self-sustaining – Scaffold horse
Reexamination Certificate
2002-03-07
2004-07-06
Thompson, Hugh B. (Department: 3634)
Fire escape, ladder, or scaffold
Self-sustaining
Scaffold horse
C182S153000, C182S225000
Reexamination Certificate
active
06758307
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a brace; more particularly, it relates to a brace useful for constructing a sawhorse with greatly increased end-to-end and side-to-side stability.
A great deal of use has been made of the sawhorse over the years. From professional carpenters to home owners, sawhorses are the widely used solution to many construction needs. Two sawhorses can be used together to support lumber while it is being cut or otherwise worked or to support a sheet of plywood to form a tabletop work surface. Sawhorses are also generally used as trestles and barricades. The characteristics of the sawhorse that contribute to its wide use include its ease of construction and disassembly, its affordability and its versatility. However there is room for improvement.
The simplest type of sawhorse is constructed out of the materials at hand, using whatever lumber is available for the cross piece and leg members of the sawhorse. The ends of the cross piece and the leg members are mitered so that they fit against each other and then nailed into place. Certainly this is a simple answer to the need for a sawhorse but it does not always result in the most satisfactory product. A sawhorse constructed in this manner is not very stable and cannot hold heavy weight loads. Nailing the legs directly into the lumber with no other means of support for the structure results in an unstable sawhorse, as the nails loosen and split the lumber when pressure is applied. It is also a dangerous solution, as it is easy to cut through the lumber being worked and into the sawhorse itself, even into the nails connecting the various members.
As the search for a safer and more stable sawhorse has progressed over time, braces and brackets were introduced to be used to join the leg members to the cross piece of the sawhorse. Many conventional sawhorses utilize a brace or bracket which connects a cross piece with four angularly disposed supporting leg members. However conventional braces have numerous shortcomings, including instability, requiring boards of a particular size and/or shape for the leg and cross piece members, and a general weakness of structure. Other sawhorse braces tend to hold the various members in a rigid manner, making the sawhorse inflexible so that it easily tips over when situated on uneven surfaces. Often tradesmen brace the two leg members together with a support from one leg member to the other, but this is unsatisfactory as with a weight load or on an uneven surface, the leg members tend to pull apart and collapse outward. The invention of this application solves this problem by providing a rear brace plate, which joins the top horizontal channel to each leg member at a point lower than the usual junction of the two leg members, just below the top channel of a brace, creating a compound angle arrangement and a significantly stronger support.
U.S. Pat. No. 5,377,780 discloses an assembly comprised of a main bracket having an inverted Y-shape with two downwardly inclined open-bottom channels to receive the leg members and an open-top channel to receive the auxiliary bracket which receives the cross piece. The improved function offered by this bracket is its ability to be folded flat. But it offers no more stability than a sawhorse with no brace or bracket. The '780 patent depends solely on the fasteners to prevent side-to-side shifting. The improved structure of Applicant's Heavy Duty Sawhorse Brace is the additional support that is the result of the compound angles used to position the leg members.
The truss brace in U.S. Pat. No. 1,780,579 teaches an elongated top horizontal channel for the cross piece which offers more stability than the traditional sawhorse but does not go far enough. The truss brace does not have a rear brace plate nor does it use the compound angles that are included in Applicant's sawhorse which eliminates end-to-end and side-to-side instability.
U.S. Pat. No. 1,797,543 (the '543 patent) discloses a bottom plate (25) that cannot be interpreted to be both a part of the top horizontal U-shaped channel and the brace plate. If the '543 patent is interpreted to have a top horizontal U-shaped channel, it does not also have a brace plate. Furthermore, even if the bottom plate (25) were a brace plate, there is no way that the bottom plate (25) could be construed to be connected to a top horizontal U-shaped channel, as is required of the brace plate of the present application. If the bottom plate (25) is a brace plate, then there is no top horizontal U-shaped channel in the Bryan reference.
The '543 patent does not teach the use of a brace plate. The bottom plate (25) set forth in the '543 patent is a part of the top horizontal U-shaped channel. Since the '543 patent does not teach a brace plate, it would not be obvious to one of ordinary skill in the art to combine the '543 patent with U.S. Pat. No. 4,457,399 to strengthen a brace plate by orienting that brace plate at an angle askew to a first axis and to a vertical line through a top channel.
The present invention satisfies a long felt need for a sawhorse brace that allows the user to employ the lumber and fasteners on hand to construct a sawhorse of superior strength and stability which virtually eliminates end-to end and side-to-side wobble without sacrificing the ease of assembly or affordability that have made the sawhorse a staple of the construction scene. More specifically, although the lumber used must be of a determined width to fit into the brace, the lumber may be of an undetermined depth so that a more stable and stronger sawhorse may be constructed from lumber with an increased depth. This needed invention is presently lacking in the prior art.
SUMMARY OF THE INVENTION
The invention is a heavy-duty sawhorse brace, comprised of a top horizontal channel to hold the cross piece of the sawhorse, two side leg channels and a brace plate. The top horizontal channel is U-shaped channel, with holes for nails or screws to secure the cross piece. The side leg channels are likewise U-shaped and have holes to secure the leg members. The brace plate is triangular in shape and extends from the top horizontal channel to each of the side leg channels. The brace plate and the length of the channels give the sawhorse increased stability by eliminating end-to-end shifting as well as increasing side-to-side stability. The brace plate in the preferred embodiment is connected at the free end of the sawhorse between the top horizontal channel and the side leg channels. However, it could be connected between those elements on the inside of the sawhorse. In either case, it is improved and new for the top horizontal channel to be elongated and extend beyond the point of connection between the top horizontal channel and the side leg channels to provide an angle for the brace plate to connect between the two.
The present invention may therefore be summarized in a variety of ways, one of which is the following: a sawhorse brace including an elongated top horizontal channel having a U-shaped cross section and a first axis, a pair of side leg channels, each of said pair of side leg channels having a U-shaped cross section and second and third axes respectively, each leg of said pair of side leg channels connected to said top horizontal channel and projecting downwardly therefrom, a brace plate, said brace plate connected to said top horizontal channel and to each leg of said pair of side leg channels, each leg of said pair of side leg channels being aligned with said top horizontal channel such that the second and third axes are at an angle askew to a line perpendicular to said first axis and askew to a vertical line running through said top horizontal channel, said top horizontal channel and said side leg channels having holes for fasteners to join a cross piece and leg members. The brace wherein said brace plate is connected to said top horizontal channel at a point remote from the point of connection of the legs of said pair of side leg channels to said top horizont
Thompson Hugh B.
Waddey & Patterson
Waddey, Jr. I. C.
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