Fire escape – ladder – or scaffold – Wall- or floor-attached – Spring-biased pivoted step or ladder
Patent
1991-07-23
1992-11-17
Chin-Shue, Alvin C.
Fire escape, ladder, or scaffold
Wall- or floor-attached
Spring-biased pivoted step or ladder
182 97, 182127, E06C 504
Patent
active
051635313
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates generally to the field of ladders, and, more particularly, to an improved ladder which is particularly adapted for use on trucks, trailers and the like, and which is adapted to be selectively rotated between an operative upright position and an out-of-the-way horizontal stored position.
BACKGROUND ART
In flatbed trucks and trailers, the driver may have to climb up on to the cargo bed to install chains, check or cover the load, and for other reasons. In many trucks and trailers, the cargo-carrying bed is about 54 inches [137.16 cm] above the ground or road.
When he has to climb up onto a flat-bed trailer, the driver will commonly climb up from the tractor. However, his access to the trailer is often restrained by the so-called "headache bumper" commonly found on the front of trailers, and which functions to prevent an unsecured load from moving inertially forwardly to strike the cab. In such event, the driver must swing himself around this obstruction. Frequently, the tractor is detached from the trailer. The driver will then climb up on a wheel, or will use the rear bumper, sometimes called a "Syracuse bumper". All of these techniques are in common use.
While climbing up on the cargo bed is cumbersome and awkward, climbing down is even more so. In many cases, the driver will simply jump down. This practice has been the source of sprained ankles, bruises, and broken bones.
Accordingly, there is believed to be a clear need for a simplified ladder structure to allow a driver to easily climb up on, and down from, the bed or cargo compartment of a truck or trailer.
DISCLOSURE OF THE INVENTION
The present invention broadly provides an improved ladder assembly, and method of operating same, which is adapted to be mounted on a suitable support, such as a truck, trailer or the like, and which is adapted to permit a person to easily climb up on, and down from, an elevated platform.
In one aspect, the invention provides an improved ladder assembly (e.g., 10) which is adapted to be mounted on a suitable support (e.g., 11), such as a truck or trailer. The support has a first surface (e.g., 23) and a second surface (e.g., 24). The improved ladder assembly broadly includes: a ladder (e.g., 12); pivot means (e.g., 13) acting between the ladder and the support and providing an axis (e.g., x--x) about which the ladder may rotate relative to the support; biasing means (e.g., 14) for urging the ladder to move in one direction along the axis, the ladder being adapted to be selectively moved between an upright position (e.g., as shown in FIGS. 1 and 3) in which one portion of the ladder is arranged to engage the support first surface, and a stored position (e.g., as shown in FIGS. 2 and 4) in which another portion of the ladder is arranged to face the support second surface; and abutment means (e.g., 15) mounted on the support and arranged to prevent the ladder from rotating in a plane perpendicular to the axis when the ladder is in the upright position; whereby the ladder may be selectively rotated between the upright and stored positions by moving (e.g., pulling) the ladder in the opposite direction along the axis, rotating the ladder to the desired angular position, and releasing the ladder to permit the biasing means to move the ladder in one direction along the axis, and then held in the desired position. The improved ladder assembly may further include interlock means arranged to act between the ladder and the support for preventing the ladder from unintentionally moving away from the support along the axis when the ladder is in the upright position.
In another aspect, the invention provides an improved method of moving a ladder between upright and stored positions relative to a support, which method comprises the steps of: mounting a ladder for pivotal movement about an axis; biasing the ladder to move in one direction along the axis; manually moving the ladder in the opposite direction along the axis by overcoming such opposing bias; selectively rotating the ladder ab
REFERENCES:
patent: 634385 (1899-10-01), Wolfe
patent: 750893 (1904-02-01), Riggs
patent: 4355701 (1982-10-01), Nicholson
Chin-Shue Alvin C.
Whiting Roll-Up Door Mfg. Corp.
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