This invention relates generally to small scaffolds and specifically to a detachable, independent step for use in connection with a small scaffold.
Various designs for vertically movable steps on posts are known. For example, U.S. Pat. No. 3,561,563 to Harsch discloses a portable step for use on a substantially vertical post. This simple design step attaches from the side. When tilted from the horizontal the step can slide vertically on the post. When in used, the step is substantially horizontal, and the edges of the step engage and bite into the post. Due to gravity any weight load on the step increases the force with which the step engages the post. However, there are problems with this design. The strength of the step is a function of the strength of the materials of which the step is constructed. Undetected flaws in the step material could result in catastrophic collapse during use. Further, these materials may be relatively expensive.
U.S. Pat. No. 2,086,280 to Matter is an angle bracket support for use on a substantially vertical post. This horizontal support could be used as a step, a support for equipment, or for a horizontal member on a scaffold. Though of a different design, Matter's portable support functions very much like Harsh's step. Matter's step uses a complicated mechanical design to give this support its requisite strength. The support has a relatively long vertical element flush with the post, a web between the horizontal support and vertical element, and a large flange which extends around the post to strengthen the structure. The detailing of this structure makes it relatively expensive to manufacture.
U.S. Pat. No. 1,098,945 to Frederick discloses a movable pole scaffold connected to a substantially vertical post. This design also uses gravitational force of the load on the horizontal element to make connection of the scaffold to the post stronger. This design is comprised of a horizontal element which supports weight connected to a yoke. The horizontal element edge, yoke legs, and a rod that transverses the yoke legs all engage the post. The problem with this design is if the transverse rod should disengage from the yoke legs or if the horizontal element should separate from the yoke the step would catastrophically fail.
USPTO Backgrounds
USPTO Backgrounds