A straight or extension ladder maintains its equilibrium when placed against a wall or other structure by the friction resistance against sliding that is created between the side rail feet and the ground surface. When this friction force is not sufficient, the base of the ladder slides away from the wall dropping the climber. In the United States, ladders are designed and tested using an angle of 75.52o which is also used as the limiting ladder set-up angle to avoid slide-out [1]. For the user to know that the ladder is properly set-up, a “rule-of-thumb” and on-product safety labels have been used. This safety strategy has room for improvement; over one-third of all ladder accidents are caused by ladder slideout. A recent proposition involves a mechanical device using wheels attached at the bottom of the ladder at each side rail. This paper initially discusses the first generation of the proposed invention and its risks. Then, a second generation of the proposed invention is discussed and nine alternative designs are compared.

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