Fire escape – ladder – or scaffold – Horizontal traversing - actuation – control – or response – Occupant actuation or control
Reexamination Certificate
1998-04-29
2001-01-30
Chin-Shue, Alvin (Department: 3634)
Fire escape, ladder, or scaffold
Horizontal traversing - actuation, control, or response
Occupant actuation or control
C182S017000, C182S103000
Reexamination Certificate
active
06179087
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an improved default-immobile ladder.
BACKGROUND ART
For safety reasons, a ladder must be immobile when used, ie. when a user is on the ladder. However, it is also desirable that the ladder can be rendered mobile for the purpose of moving the ladder to another location.
A number of different solutions have been proposed in which some form of mobility means, such as wheels and castors, have been used, with the mobility means being movable between a retracted immobile position and a downwardly extended mobile position.
It is highly desirable that the mobility means return to the retracted immobile position as a default so that, in the absence of an applied mobilising force, the ladder is immobile.
A default-immobile ladder is disclosed in French Patent Publication 2,171,571. The ladder includes a rectangular frame carrying four wheels or castors. The frame can be urged downwardly in response to actuation of a lever thereby lifting the ladder and rendering the ladder mobile. The ladder returns under gravity to the immobile position when the lever is released, ie. the immobile position is the default.
The present invention aims to provide an improved default-immobile ladder.
DISCLOSURE OF INVENTION
In one aspect the invention resides in a default immobile ladder including:
a plurality of mobility means simultaneously displaceable between a ladder immobile position in which the feet of the ladder contact a supporting surface and a ladder mobile position in which the plurality of mobility means extend beyond the feet of the ladder thereby lifting the feet of the ladder away from the supporting surface against the effect of gravity; and
actuable means for simultaneously displacing the plurality of mobility means from the ladder immobile position to the ladder mobile position,
wherein a mobilising force applied to the actuable means simultaneously displaces the plurality of mobility means to the ladder mobile position, whereafter a horizontal moving force applied to the actuable means moves the mobilised ladder about on the supporting surface, and wherein discontinuation of said mobilising force on the actuable means causes the plurality of mobility means to return to the ladder immobile position regardless of whether the ladder is loaded or unloaded,
characterised in that the mobilising force is applied to the actuable means in a substantially vertical direction.
Preferably, the mobilising force and moving force are applied to the actuable means by a user's hands and the actuable means is adapted to receive the user's hands in horizontally spaced locations whereby steerage of the mobilised ladder on the support surface is facilitated.
Preferably, the actuable means includes a pivotably mounted lever which adopts a substantially horizontal orientation when the plurality of mobility means are in the ladder mobile position.
Preferably, the actuable means includes an integral pair of levers, each lever being operatively connected to a pair of mobility means.
In another aspect the invention resides in a default immobile ladder including:
two pairs of mobility means, each pair being displaceable between a retracted position and an extended position; and
a pair of lever means, each lever means being associated with a pair of mobility means for displacing the associated pair of mobility means from the retracted position to the extended position,
wherein a mobilising force applied to a lever means displaces the associated pair of mobility means to the extended position, and wherein discontinuation of said mobilising force on the lever means causes the associated pair of mobility means to return to the retracted position regardless of whether the ladder is loaded or unloaded.
Preferably, the two lever means are integral such that the two pairs of mobility means are simultaneously extended.
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Chin-Shue Alvin
Custom Ladder Company Pty. Ltd.
Heslin & Rothenberg, P.C.
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