Fire escape – ladder – or scaffold – Wall- or floor-attached
Reexamination Certificate
2001-04-27
2002-12-17
Stodola, Daniel P. (Department: 3634)
Fire escape, ladder, or scaffold
Wall- or floor-attached
C182S150000
Reexamination Certificate
active
06494291
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates in general to the construction of scaffolding device and in particular to an improved scaffold which includes front and rear structures which are pivotally interconnected by parallel side braces so that the front structure may be suspended by means of a flexible element outwardly from the rear structure to form a cage.
And further the rear structure of the scaffolding device is fixed and settable safely, reliably and firmly to a support structure such as an I-beam in a place to construct.
2. Description of the Prior Art
The invention relates to the construction of a foldable scaffold device which is particularly useful in the erection of buildings or the construction of ships, etc. The foldable scaffold device of prior art is well known as shown in The U.S. Pat. No. 4,029,173.
And known scaffold device is secured in position on a supporting structure such as a beam through a fitting means. Said fitting means consists of a fitting member connected to a rear structure, a bolt connected to said fitting means, pawl being slidably supported on said bolt and a nut being threaded on said bolt backwardly behind said pawl. In an erected position of said scaffold device, said fitting member directly contacts with a front edge of H-sectional structure and said pawl contacts with a rear edge of a H-sectional structure and thereafter said pawl is tied from backward through said nut. Said fitting member of said scaffold device is fitted up to a hinge being freely rotatable to any directions and unstable. And then said scaffold device is unstably adapted and supported on a support beam with unsteady states.
Disadvantage of the known structures is that they are inclined in case of attaching a scaffold device by a strong threading force of said nut, because rear structures are pulled backwardly by a reaction of said threading. And the scaffold device is rotated to a direction such as pivoting a contact point with a H-sectional structure, and therefore it will be feared that work man in a scaffold floor is exposed himself to danger, for example, as the rear frame structure may be yielded and broken by a weight of him in case when he gets on an inclined scaffold cage, or as the scaffold may swing around the hinge.
SUMMARY OF THE INVENTION
In accordance with the present invention there is provided an erectable and transportable scaffold cage adapted to be engaged on and supported on a support beam. Said scaffold cage comprises front and rear frame structures which are pivotally interconnected by means of parallel side braces which are connected between the frame structures. A scaffold plate is pivotally connected to the lower ends of each of the front and rear frames. And the front frame is pivotally outwardly from the rear structure to form a cage within the front and rear structures and the side braces having a floor formed by a scaffold plate. The plate has upright bottom edges, which fit flush against the insides of an angle member forming the sides of the front frame structure so that it facilitates the holding of the structure in an erected cage forming position. A flexible member such as a chain is connected between the upper ends of each side of the front structure to the upper ends of each side of the rear structure. The rear structure carries a holding bracket connected to a bolt having a front pawl and a rear pawl, which is slidable therealong and which may be engaged against a support structure such as an I-beam by threading a wing nut onto the bolt behind said rear pawl to lock it in position.
And further the rear structure also carries a holding bracket consisting of an unity and being rigidly fixed and connected to a bolt having a front pawl and a rear pawl which is slidable therealong and which may be engaged against a support structure such as an I-beam by threading a wing nut onto the bolt behind the rear pawl to lock it in position.
Accordingly, it is an object of the invention to provide an erectable and transportable scaffold cage, which is not inclined even when it may be engaged with a strong force against a support structure such as an I-beam by threading a wing nut.
A further object of the invention is to provide an erectable and transportable scaffold cage, which is fixed and settable safely, reliably and firmly to a support structure without unsteady states.
REFERENCES:
patent: 1795808 (1931-03-01), Thompson
patent: 2049893 (1936-08-01), Chicoine
patent: 2854292 (1958-09-01), Schaeffer
patent: 2916244 (1959-12-01), Renfroe
patent: 4029173 (1977-06-01), Wakabayashi
patent: 5863020 (1999-01-01), Olson et al.
patent: 338145 (1989-10-01), None
McGlew and Tuttle , P.C.
Stodola Daniel P.
Thompson Hugh B.
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