Scissor Linkage Post Puller for Star Picket Removal
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Solution Overview
Problem
Existing mechanisms for removing star picket fence posts from the ground are labor-intensive, prone to slipping, and ineffective in hard soil conditions, particularly when using plate-type removers or chain mechanisms.
Innovation Solution
A post puller featuring a scissor linkage with a coupling assembly and a post gripping assembly comprising movable gripping jaws that form a Y- or T-shaped opening to securely engage the star picket, coupled with a hydraulically actuated pulling mechanism for efficient removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plate-type remover is used to remove star pickets, then the picket can be removed from the ground, but the plate may bend the picket during removal and is prone to slipping
Solution Approach 1:
The gripping assembly features jaws with specific geometric configurations (V-shaped, U-shaped, or clamp-style) that match the star picket's cross-section. This local geometric adaptation ensures the gripping surfaces contact the picket at optimal points, distributing force evenly to prevent bending while maintaining secure grip without slipping.
Solution Approach 2:
The gripping assembly is designed to dynamically adapt to the picket's position and orientation. The movable jaws can adjust their configuration based on the picket's angle and depth in the ground, allowing the system to maintain effective gripping contact even as the picket is extracted at varying angles, thereby preventing both slipping and deformation.
2Ease of operation
If a chain with half hitch is used to remove star pickets, then the mechanism is simple to operate, but it is very prone to slipping
Solution Approach 1:
The invention replaces the friction-based chain hitch system with a mechanical gripping system that uses geometric interlocking and direct contact forces. The gripping jaws with specialized shapes (V-shaped, U-shaped, or clamp-style) mechanically engage the star picket's geometry, providing reliable grip that does not depend on friction alone, thereby eliminating the slipping problem while maintaining ease of operation through simple actuation.
3Device complexity
If manual labor is used to remove fence posts, then no special equipment is needed, but the process is labor and time intensive
Solution Approach 1:
The post puller is designed as a universal attachment that can be connected to various common equipment platforms (tractors, excavators, skid steers, front-end loaders). This multi-functionality allows a single gripping assembly design to serve multiple agricultural and construction applications, dramatically improving productivity by leveraging the power of existing equipment while maintaining relative simplicity through standardized attachment interfaces.
Solution Approach 2:
The gripping assembly is actuated by hydraulic or pneumatic systems integrated with the host equipment's power system. This allows powerful gripping forces to be generated automatically through fluid pressure, enabling rapid and efficient picket removal without requiring significant manual labor, while the system remains relatively simple through direct integration with existing equipment hydraulics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The post puller effectively grips and removes star pickets from the ground with reduced labor and increased efficiency, allowing for secure grip and easy relocation of fence posts, even in hard soil conditions.
Implementation Method 1
a scissor linkage having a coupling end and a post end, the scissor linkage being moveable between a first position and a second position
Implementation Method 2
coupled with a hydraulically actuated pulling mechanism for efficient removal
Data Source
AI summary
There is disclosed herein a post puller (10) for removing a fence post from the ground. The post puller (10) includes a scissor linkage (12) having a coupling end (14) and a post end (16) wherein the scissor linkage (12) is moveable between a first position and a second position. The post puller (10) further includes a coupling assembly (18) located at the coupling end (14) of the scissor linkage (12). The coupling assembly (18) is operatively adapted to connect the scissor linkage (12) to a pulling mechanism. The post puller (10) further includes a post gripping assembly (26) located at the post end (14) of the scissor linkage (12). The post gripping assembly (26) includes a first gripping jaw and a second gripping jaw (28, 30). The first and second gripping jaws (28, 30) are movable between an open position and a closed position as the scissor linkage (12) is moved between the first and second position. The first and second gripping jaws (28,30) are adapted to form a picket receiving opening (32) shaped to receive a star picket when the first and second gripping jaws (28, 30) are located in the closed position.