| 摘要 |
A pump jack for a scaffold in a system to support a work platform and move the platform up and down a pole to access a vertical work surface. The pump jack includes an L-shaped framework having a horizontal frame member which supports the work platform and a vertical frame member. The vertical frame member having laterally opposing Z-shaped channels, each having a leg that bends about the pole and extends inward toward the pole. The pump jack includes an upper shackle supported by the framework. The pump jack includes a lower shackle supported by the framework, which with the upper shackle applies a coupling force for gripping the pole. The pump jack includes a pump arm lever pivotably coupled to the vertical frame member to step upwardly the pump jack relative to the pole. The pump jack includes a crank mechanism coupled to the vertical frame member. A method for supporting and moving a work platform up and down a pole to access a vertical work surface.
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