Fire escape – ladder – or scaffold – Unitary foldable – rigid scaffold or ladder – Trestle
Reexamination Certificate
2000-08-08
2002-12-03
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Unitary foldable, rigid scaffold or ladder
Trestle
C182S225000
Reexamination Certificate
active
06488119
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to sawhorses, scaffolds and trestles, and more particularly to a sawhorse that may be opened for use and folded to collapse for storage.
Sawhorses are used as racks or trestles to support construction materials and other objects. With their wide base, sawhorses provide a relatively stable support for a workpiece while being fairly portable. However, non-folding sawhorses require substantial space for storage and transportation.
Folding sawhorses therefore were created to solve the storage space problem and to allow for easier transportation. However, prior folding sawhorses had many shortcomings. Some prior folding sawhorses could not withstand sideways motion in the load they supported. This was particularly a problem with the type of folding sawhorse described in U.S. Pat. No. 4,884,658 to Banfield. The legs of this type of folding sawhorse that were positioned on a common side of the sawhorse were not in rigid contact with each other. The legs tended to pivot with respect to the upper central member of the sawhorse when the sawhorse was under load and therefore the sawhorse did not provide sufficient support when its load moved laterally with respect to the central supporting member.
Other folding sawhorses, such as the sawhorse described in U.S. Pat. No. 4,790,411 to Ottoson, provided significantly less vertical support than did non-folding sawhorses. The legs of these sawhorses tended to splay out under the pressure of applied weight because the sawhorse's opposing legs were not rigidly fixed to one another when the sawhorse was unfolded for use.
A folding sawhorse should readily unfold for use and fold up again for storage. Since most projects of the home owner are of short duration, if the sawhorse does not easily expand and collapse, it will be seldom used. Some folding sawhorses are both rigid and sturdy because their four legs are fixed relative to one another, but are difficult to unfold and fold.
The folding sawhorse disclosed herein is an improvement of the sawhorse disclosed in the U.S. Pat. No. 5,351,785, the disclosure of which patent is incorporated by reference in its entirety into this disclosure. The slot/sliding pin combinations of that sawhorse are replaced by a paired pin-rib engagement to provide enhanced stability.
SUMMARY OF THE INVENTION
It is therefore a general object of the invention to overcome the above described limitations and others associated with the prior folding sawhorses. More particularly, it is an object of the invention to provide a folding sawhorse that collapses or folds easily for storage and expands easily to a sturdy position for use.
To accomplish these objects, a folding sawhorse according to the invention includes a first frame, a second frame, a hinge connection between the frames, and a substantially rectangular shelf. The first frame includes a first elongated crossmember, a first pair of substantially parallel spaced apart legs extending from the first crossmember, and a first brace extending between the first pair of legs. The second frame includes a second elongated crossmember, a second pair of substantially parallel spaced apart legs extending from the second crossmember, and a second brace extending between the second pair of legs.
The hinge connection pivotally connects the first crossmember to the second crossmember so as to enable the first frame to pivot with respect to the second frame about a hinge axis. The hinge axis extends substantially parallel to the longitudinal axes of the cross members associated with both the first and second frame.
The shelf has, at a first side thereof, a slidable attachment connecting the shelf to opposing ribs formed on the first pair of legs. At a second side, the shelf pivotally connects to the second frame. In this manner, the shelf is capable of sliding along the slidable attachment and pivoting at the second side between a storage position and a working position. In the storage position the first frame lies generally parallel to the second frame with the self folded therebetween. In the working position the planes defined by the first and second frames form generally two sides of an “A” shape with the shelf forming the cross portion of the “A” shape.
In the preferred form of the invention the shelf is pivotally connected to the second frame along the second brace and rests upon both the first and second braces when the sawhorse is in the working position. Since the shelf must pivot upwardly to collapse the sawhorse, the shelf serves to hold the sawhorse firmly in the working position and prevents the sawhorse from collapsing during use. When the sawhorse is in the working position, the shelf rigidly holds the four legs in position so that they do not move with respect to one other. Such rigid positioning of the legs, coupled with the hinge connection between the rigid frames prevents relative motion among the sawhorse components to produce a sturdy rigid support structure. In the preferred embodiment the slidable attachment comprises a pair of offset pins which yoke a rib in the associated leg to provide stability.
REFERENCES:
patent: 5351785 (1994-10-01), DuRapau
DuRapau Rick
Dvoracek Joe
Chin-Shue Alvin
Lehigh Consumer Products Corp.
LandOfFree
Folding sawhorse with locking shelf does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Folding sawhorse with locking shelf, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Folding sawhorse with locking shelf will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2989900