Post Hole Digger Handle Pivot Mechanism
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Solution Overview
Problem
Existing post hole diggers face challenges with a limited range of motion, weight, and ergonomic issues, particularly with traverse pivot points that require awkward hand positioning and increased effort due to the need for wider spans during operation.
Innovation Solution
A post hole digger design featuring a traverse pivot point located on the medial portions of handle members and an offset blade assembly pivot point, allowing for reduced range of motion and maintaining handles in a vertical, parallel orientation, along with a hand ledge for ergonomic support and reduced weight through shorter handle assemblies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If longer handles are used to increase lever arm and closing force, then the closing force on blade members is improved, but the tool becomes too heavy to lift repeatedly and too unwieldy to use comfortably
Solution Approach 1:
The handle assembly is segmented into two separate handle members that pivot relative to each other at a traverse pivot point. This segmentation allows each handle to be shorter while still providing sufficient closing force through the mechanical advantage of the scissor-like pivot mechanism, reducing overall tool weight and improving maneuverability.
Solution Approach 2:
The traverse pivot point creates a dynamic scissor mechanism where the handles move between parallel and angled positions. This dynamic configuration allows the handles to generate increased closing force when angled during the digging cycle, while maintaining a compact parallel position for easy lifting and transport, thus providing variable force characteristics without constant weight penalty.
2Force
If longer handles are used to increase lever arm, then the closing force on blade members is improved, but the range of motion and maneuverability deteriorate
Solution Approach 1:
By dividing the handle system into two independently pivotable handle members connected at a traverse pivot point, the design achieves long effective lever arms when needed for closing force, while maintaining compact overall dimensions for easy maneuvering. The segmented structure allows the handles to be positioned optimally for force application without requiring excessive handle length that would hinder maneuverability.
Solution Approach 2:
The dynamic scissor mechanism allows the handles to transition between a compact parallel configuration for easy storage and transport, and an extended angled configuration for maximum closing force. This dynamic adaptation enables the tool to provide high closing force when needed while maintaining excellent maneuverability during positioning and transport phases.
3Force
If traverse pivot point is used to connect handles, then the closing force is improved, but the hand positioning becomes awkward and effort increases
Solution Approach 1:
The traverse pivot point mechanism serves multiple functions: it generates closing force through the scissor action, maintains handle stability during operation, and positions the handles in a naturally comfortable parallel alignment for the user. This multi-functionality addresses both the force generation requirement and the ergonomic positioning requirement simultaneously.
Solution Approach 2:
When the handles are in the parallel position, the traverse pivot mechanism creates a balanced, equipotential state where the handles are naturally aligned at an ergonomic height and angle for the user. This balanced configuration minimizes the effort required to hold and position the handles, making the operating position naturally comfortable while still providing full closing force capability.
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
This design enhances ease of use by minimizing the range of motion and weight, improving ergonomics by maintaining handles in a comfortable position and reducing the effort required for operation, while allowing efficient dirt collection and removal.
Implementation Method 1
a post hole digger having a first, traverse pivot point, located on the medial portions of two handle members, and a second, blade assembly pivot point located at the medial point of the blade assemblies
Implementation Method 2
the closing force acting on the blades is related to the force applied to the handles. The force applied to the handles was enhanced by the length of the lever arm created by the length of the handle
Data Source
AI summary
This invention provides a post hole digger having a first, traverse pivot point, located on the lower section of two handle members, and a second, blade assembly pivot point located at the medial point of the blade assemblies. Because the first pivot point is a traverse pivot point, the handle members are only required to travel through a limited range of motion. Additionally, the second, blade assembly pivot point is preferably an offset pivot point. Thus, because the second, blade assembly pivot point is disposed at a medial point of the blade assemblies, the motion of the handle members, which are coupled to the upper ends of the blade assemblies, is reversed relative to the lower ends of the blade members.