Patent ID: 9624690
Date: 2017-04-18
CPC Classifications: E04H

Claim:
1. A post puller for pulling a post from a ground embedded position standing upright from a ground surface, the post puller comprising: a lifting member having a coupling point thereon that is configured for attachment to lifting arrangement of a working machine to enable upward lifting of said lifting member by the lifting arrangement of the working machine; a sliding sleeve attached to the lifting member; a guide shaft about which the sliding sleeve is disposed for axial sliding of the sleeve up and down along a longitudinal axis of the guide shaft; a pair of movable grippers pivotally supported on the guide shaft by respective pivotal connections on opposing sides of a central longitudinal plane thereof at a fixed location along the longitudinal axis of the guide shaft, each movable gripper having an inner end with a cam-shaped gripping surface that faces across the central longitudinal plane of the guide shaft toward the cam-shaped gripping surface of the other movable gripper, and an opposing outer end spaced laterally outward to a respective side of the guide shaft, each cam-shaped gripping surface increasing in a radial distance thereof from a pivot axis of the respective pivotal connection in a direction moving upward from an imaginary axis intersecting the pivot axes of the pivotal connections; a pair of links having upper ends pivotally coupled to the lifting member and respective lower ends each pivotally coupled to a respective one of the movable grippers proximate the outer end thereof, whereby raising of the lifting member by the working machine with a web or flange of the post received in a space between the inner ends of the movable grippers lifts the outer ends of the movable grippers via the pair of links, thereby lowering the inner ends of the grippers about the pivot axis and bringing the cam-shaped gripping surfaces into closer proximity to one another to grip the web or flange of the post between the gripping surfaces and pull the post from the embedded position under further raising of the lifting member by the working machine.