Fire escape – ladder – or scaffold – Safety device for ground-supported ladder
Patent
1985-07-19
1987-10-13
Machado, Reinaldo P.
Fire escape, ladder, or scaffold
Safety device for ground-supported ladder
182200, 2481882, E06C 744
Patent
active
046992472
DESCRIPTION:
BRIEF SUMMARY
When a ladder is erected in the correct disposition, both its lower stile ends should be resting on a firm surface, and the rungs should be horizontal. These requirements can rarely be met concurrently since typical ground surfaces are not usually both flat and horizontally level.
Two common solutions, which are employed, involve packing and wedging. It if fortuitous if packing is of the correct thickness and makeshift attempts to fill out may be fragile and usually unstable. Wedges for supporting the lower end of one stile are disclosed in U.S. Pat. Nos. 3,993,275 and 4,304,318. However, such a wedge is also unstable since, if the ladder is rocked from side to side in use, the wedge is prone to move as the load is removed from the wedge and reapplied, and there is then a tendency for the stiles of the ladder to "walk" or rotate about the axis of one stile. Also the devices disclosed in these two documents have straight rigid ground engaging side edges and these will rock on any local raised ground.
Attachments, such as that disclosed in GB-A-1367489, which are rigidly attached to the bottom of a ladder, are known, but these are time consuming and difficult to use, make it difficult to move the ladder, require adjustment each time the ladder is moved, and are prone to jamming of the moving parts.
In accordance with the present invention, a device for simultaneously supporting the bottom ends of both the stiles of a ladder from the ground comprises an upper surface which is supported by ground engaging feet, and so constructed that when the feet are resting on horizontal ground, the upper surface presents a graded range of heights such that when the ladder stiles are rested on the upper surface, the relative heights of the stiles from the ground may be altered by a change of location of the stiles on the upper surface, whereby the device can be selectively positioned on level or sloping ground so that both stiles of a ladder may be rested on the device with the ladder rungs horizontal.
With this construction, any ladder can be readily levelled on level or sloping ground by appropriate manipulation of the device between the lower stile ends and the ground. The upper surface may have stepped and/or inclined parts and will be arranged so that the device can space the bottom ends of both ladder stiles from the ground by the substantially same distance when the ground is substantially level, or by variously different distances when the ground is sloping.
In addition to levelling the ladder, the device may be arranged to provide on the lower stile ends a reaction with a component directed towards the base of a wall against which the ladder is leaning, when standing on the device, to inhibit any tendency for the lower end of the ladder to stip outwards across the device in the direction away from the wall.
One important feature of the new device is that its upper surface is large enough to support the lower ends of both ladder stiles. As a result, in the event of one side of the ladder lifting in use, for example as a result of movement of a user climbing or standing on the ladder, the full weight of the ladder and user will remain on the device, preventing movement of the device and any consequential tendency of the ladder to "walk" or twist.
A second important feature is that the device is provided with feet which support the device locally with the rest of the device spaced above the ground. This provides for stable support on uneven ground. Three feet will always provide such stable support but two wide feet or more than three feet are not excluded. For example, they may be flexible or flexibly mounted, e.g. pivotally mounted in pairs, so that they can adjust to the unevenness of the ground.
In one particularly cheap and convenient construction, the upper surface is the upper surface of a substantially triangular platform having, adjacent to each of its three corners, a respective one of the ground engaging feet. For example, when the device is resting with the feet on level ground, one edge of the upper surfa
REFERENCES:
patent: 2767032 (1956-10-01), Mitchell
patent: 3086612 (1963-04-01), McKinley
patent: 3199629 (1965-08-01), Fagaly
patent: 3993275 (1976-11-01), Lucas
patent: 4069890 (1978-01-01), Gottliebsen
patent: 4135335 (1979-01-01), Jensen
patent: 4304318 (1981-12-01), Webb
patent: 4456095 (1984-06-01), Hodson
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