Pump jack and method
View Patent ↗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.
1. 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 comprising:
an L-shaped framework having a horizontal frame member capable of supporting the work platform and a vertical frame member, the vertical frame member having laterally opposing Z-shaped channel members, each having a leg that bends about the pole and extends inward toward the pole;
an upper shackle supported by the framework;
a lower shackle supported by the framework, which with the upper shackle capable of applying a coupling force for gripping the pole;
a pump arm lever pivotably coupled to the vertical frame member to step upwardly the pump jack relative to the pole; and
a crank mechanism coupled to the vertical frame member.
2. A pump jack as described in claim 1 wherein the framework includes a vertical frame member having a separator extending between and connected to the opposing Z-shaped channel members, the separator maintaining the Z-shaped channels in a spaced relationship.
3. A pump jack as described in claim 2 wherein each Z-shaped channel member has a web with a first side from which the leg bends about the pole and extends inward toward the pole, and a second side from which a second leg extends outward away from the pole.
4. A pump jack as described in claim 3 wherein the leg and the second leg extend in opposite directions from each other relative to the pole.
5. A pump jack as described in claim 4 wherein the horizontal frame member supports the vertical load of at least 2,750 pounds.
6. A method for supporting and moving a work platform up and down a pole to access a vertical work surface comprising the steps of:
placing the work platform on a horizontal frame of a pump jack of an L-shaped framework of a pump jack; and
pumping a pump arm lever coupled to a vertical frame member of the framework to move the pump jack up the pole, where the vertical frame member has laterally opposing Z-shaped channel members, each having a leg that bends about the pole and extends inward toward the pole.
7. A method as described in claim 6 including the step of supporting a vertical load of at least 2,750 pounds with the horizontal frame member.