Fire escape – ladder – or scaffold – Platform
Reexamination Certificate
1999-05-26
2001-11-20
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Platform
C182S119000
Reexamination Certificate
active
06318499
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to scaffolding planks. More specifically, this invention is directed to a composite scaffolding plank and a method for forming the same. The composite scaffolding plank is an improved, low cost wide scaffolding plank formed by pinning and anchoring a plurality of narrow wooden boards, at least one of which is a whole natural wooden board and at least one of which is a laminated wooden board. In addition, the strength of a wooden plank may be improved by cutting the plank longitudinally into sections, adding at least one laminated wooden board and pinning the plank sections together as described above.
2. Related Art
Prior to this invention, two types of scaffolding planks existed in the prior art: the solid single board plank and the laminated plank. The solid single board plank comprises one wide wooden board. The laminated plank is constructed from multiple layers of wooden strips glued together. Each of the two types of prior art scaffolding planks have advantages and disadvantages.
With respect to the disadvantages, due to the limited resources of old growth forests and the harvesting schemes for new growth timber, the yield of wooden boards wide enough from which to construct a solid single board plank is decreasing. Typically, only the center portion of a large tree is sufficiently broad to produce a solid single board plank. Thus, with decreasing yield, the solid single board planks are becoming more costly and difficult to make. The main disadvantage of laminated planks is that laminated planks primarily consist of glued layers of wooden strips, which glued layers of wooden strips absorb substantial amounts of moisture. After absorbing enough moisture, the wooden fibers of the laminated plank soften and the moisture hastens decay in the scaffolding board. Likewise, any time one of the veneers of the laminated plank cracks, the laminated plank looses its strength and consistency and can also no longer be used as a scaffolding.
With respect to the advantages, the solid single board planks are comparitively stronger and easier to manufacture than the laminated planks. In turn, the laminated planks, if oriented correctly, are comparitively more rigid than the solid single board planks. Moreover, laminated planks, when used in dry conditions, do not shrink as much as solid single board planks.
Applicant's co-pending application entitled Composite Scaffolding Plank and Method for Forming Same, which was filed on even date herewith, provides a safe third alternative to the solid single board plank and the laminated plank and reduces, if not eliminates, the disadvantages of the two types of prior art planks. However, the plank disclosed in Applicant's co-pending application does not benefit from the advantages inherent in the prior art solid single board plank and laminated plank.
It would be beneficial to the prior art to construct a scaffolding plank that optimizes and combines the advantages of both the single solid board plank and the laminated plank while greatly reducing, if not eliminating, their respective disadvantages.
Scaffolding planks are however strictly regulated. The Occupational Safety and Health Administration, OSHA, as well as the Southern Pine Inspection Bureau, SPIB, outline strict standards for scaffolding planks. Pursuant to such regulations, scaffolding boards must comply with certain width, breakage, and quality standards. The OSHA and SPIB standards are strict because workers entrust their lives to the scaffolding. The prior art would thus benefit from a scaffolding plank, as described above, that meets and preferably exceeds the OSHA and SPIB standards.
Because the lives of workers hinge on the integrity of scaffolding planks, any safety factors that can be added to a scaffolding plank greatly enhance the value of the scaffolding plank. It would be beneficial to the prior art to provide a scaffolding plank, as described above, that also includes an additional worker safety factor.
Moreover, so that workers do not slip while stepping on the scaffolding planks, it is important for the scaffolding planks to have a non-slippery top surface. Natural wooden boards are typically smooth, and must be manipulated to be provided with an artificial non-slippery top surface. However, such manipulation normally also weakens the board. It would thus be beneficial to the prior art to provide a scaffolding plank that includes a non-slippery top surface. It would also be beneficial to the prior art to provide such a non-slippery scaffolding plank that includes natural wooden boards which have not been weakened during any artificial surface texturing.
Manufactured wide boards for scaffolding are unknown to the prior art. Prior references, however, disclose structural wood assemblies formed from a plurality of smaller wood boards. Illustrative of such wood assemblies are U.S. Pat. No. 2,650,395 that issued to de Anguera on Sep. 1, 1953, U.S. Pat. No. 5,120,378 that issued to Porter et al. on Jun. 9, 1992, U.S. Pat. No. 4,534,448 that issued to Trainer on Aug. 13, 1985, U.S. Pat. No. 1,167,988 that issued to Faulkner on Jan. 11, 1916, U.S. Pat. No. 2,569,450 that issued to Bouton on Oct. 2, 1951.
The assembly shown in U.S. Pat. No. 2,650,395 discloses a method of forming wood flooring from relatively narrow pieces of wood having varying lengths. The pieces of wood are placed in a number of parallel rows wherein the pieces are placed end to end. A plurality of spaced thin connector keys are driven into lateral bores in the aligned pieces and hold the pieces together.
U.S. Pat. No. 5,120,378 discloses an apparatus and method for producing a prestressed wood material beam. The wood beams are held together using adhesives or mechanical fasteners such as nails or staples.
Though the above mentioned devices and assemblies may be helpful for their intended purposes, none disclose a manufactured scaffolding plank that meets OSHA and SPIB requirements and that optimizes and combines the advantages of both the single solid board plank and the laminated plank while greatly reducing, if not eliminating, their respective disadvantages.
SUMMARY OF THE INVENTION
Accordingly, the objectives of this invention are to provide, inter alia, a composite scaffolding plank and method for forming same that:
meets the OSHA and SPIB requirements;
optimizes and combines the advantages of both the single solid board plank and the laminated plank while greatly reducing, if not eliminating, their respective disadvantages;
comprises a plurality of relatively narrow boards to form a relatively wide board;
includes a tensioning device that pulls the boards together and prevents their separation;
includes an additional worker safety factor;
includes spaced connectors such that, when one of the members of the scaffold board breaks, the member and the remainder of the scaffolding board remains solid beyond the nearest connector;
includes separate parallel boards such that a break initiated by an imperfection in one of the narrow boards will not spread to the connected narrow boards;
includes a non-slippery top surface;
includes a non-slippery top surface and also includes natural wooden boards which have not been weakened during any artificial surface texturing;
affords an inexpensive source for relatively wide boards and alleviates the scarcity of wide boards; and
is easily and inexpensively manufactured from readily available resources.
Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related.
To achieve such improvements, my invention is a composite scaffolding plank made from a plurality of wooden boards positioned in side to side parallel abutment. At least one of such boards is a whole natural wooden board, and at least one of such boards is a laminated wooden board. A plurality of spaced pins extend transversely through the wooden boards. A cam means on the pins pulls and holds the boards together. In addition, my invention is a method of form
Cook Carl R.
Honein Joseph
Chin-Shue Alvin
Johnson Kenneth H.
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