Fire escape – ladder – or scaffold – Ladder – Supporting surface compensating means
Patent
1982-08-03
1984-06-26
Machado, R. P.
Fire escape, ladder, or scaffold
Ladder
Supporting surface compensating means
182 15, 2481883, E06C 744
Patent
active
044560958
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
(1) Field of the Invention
This invention relates to a levelling device for ladders and the like.
(2) Description of the Prior Art
Difficulty is often experienced in providing a firm and level foundation for a ladder, trestle or the like which is required to be used on sloping ground. In these circumstances, it is usual to use blocks to support one leg of the ladder above the lower level of ground if the slope is not excessive, but in a case where the slope is such that the ladder when in its upright or working position, has one leg a considerable distance above the ground, the use of a sufficiently high block or assembly of block may be unreliable and very dangerous.
BRIEF SUMMARY OF THE INVENTION
The present invention has been devised with the general object of providing a levelling device by means of which a ladder (which term is hereinafter in the specification and claims to be taken to include a trestle, chair, table, legged or based object or other like article), may be firmly supported upon a sloping foundation or even upon two steps at different levels, for example, the device being quickly and easily adjustable to suit widely different requirements, and having means for automatically locking the levelling device in required/adjusted position.
With the foregoing and other objects in view, the invention resides broadly in a levelling device for a ladder including a frame transversely applicable to the lower part of the ladder; apertured locking members pivoted to the frame; and an arcuate member slidable through the locking members and terminating in feet for supporting the ladder; the locking members being pivotally tiltable under downward pressure of the frame to lock the arcuate member against slidable movement therethrough. The frame may be provided with a support for the uprights of a ladder and means for releasably securing the ladder uprights firmly to the frame; or alternatively the frame may be incorporated in the structure of the ladder and serve as a bottom rung therefor. The locking means are preferably spring-loaded to positions freeing the arcuate member for slidable movement therethrough, and enabling the ladder to be easily brought to upright safe working position despite the feet being at different levels. Other features of the invention will become apparent from the following description.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
In order that the invention may be readily understood and carried into practical effect, reference is now made to the accompanying drawings, wherein:
FIG. 1 is a perspective view of a levelling device according to the invention applied to a conventional ladder;
FIG. 2 is a perspective view of a levelling device incorporated in a ladder;
FIG. 3 is a sectional view of one of the automatic locking means of the levelling device;
FIG. 4 is a perspective view of a levelling device incorporated in a trestle; and
FIG. 5 is a perspective view of one of the automatic locking means of the levelling device of FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring initially to FIGS. 1 and 3 of the drawings, a levelling device for a ladder, trestle or the like includes a mounting frame 10 having a transverse inverted channel 11 with its top member or web projected forwardly to form with the channel, a platform 12. The mounting frame also includes a tubular member of inverted U-shape forming an arch 13 the bottom ends of which are welded or otherwise rigidly secured to the sides of the channel 11, and braced gussets 14, the two sides of the arch being interconnected by a tubular cross-member 15.
A support arc 16, being a length of metal tube bent to substantially semi-circular form, passes closely through a pair of locking devices 17 at the sides of the channel 11 and midway between these locking devices the support arc is closely but slidably engaged in the middle part of the channel. The sides of the arc, which constitute support legs, are connected by universal joints at 18 to a pair of disc-shaped feet 1
REFERENCES:
patent: 1127287 (1915-02-01), Sadler
patent: 1542775 (1925-06-01), Husted
patent: 1928158 (1933-09-01), Ruse
patent: 2289499 (1942-07-01), Husted
patent: 2555036 (1951-05-01), Husted
patent: 2835427 (1958-05-01), Balcar
patent: 2960182 (1960-11-01), Swanson
patent: 2971602 (1961-02-01), West
Machado R. P.
Milba Properties Pty. Ltd.
Weaver D. Paul
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