Elastomeric Shaft Extraction Device with Slide Hammer
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Solution Overview
Problem
Hunting and target archery arrows often become deeply embedded in wood or similar objects, making it difficult to remove them intact and undamaged, especially when the shafts are made of expensive materials like carbon fiber.
Innovation Solution
A shaft extraction device featuring an elongated gripping element with a clamping device and a force applying element, including a slide weight assembly, allows for secure gripping and incremental force application parallel to the shaft axis, preventing damage during extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If excessive force is applied to extract the arrow shaft, then the extraction force is sufficient to remove the embedded object, but the shaft may be crushed or damaged
Solution Approach 1:
The patent employs an elastomeric material (flexible shell) that lines the interior surface of the gripping element. This elastomeric layer conforms to the shaft surface, distributing extraction forces uniformly across the contact area rather than concentrating them at discrete points. The flexibility of this thin film allows it to deform slightly under load while maintaining continuous contact, preventing localized stress concentrations that would crush or damage the shaft.
2Device complexity
If a simple gripping tool is used, then the device complexity is low, but the tool cannot securely grip the shaft without slippage during extraction
Solution Approach 1:
The elastomeric material provides enhanced friction and grip security through its flexible, conforming nature. This single material addition significantly improves grip reliability without requiring complex mechanical features such as multiple clamping mechanisms, adjustment devices, or specialized gripping geometries.
Solution Approach 2:
The elastomeric material changes the surface properties (friction coefficient, compliance, contact area) of the gripping element, allowing a simple device structure to achieve secure grip through material property optimization rather than mechanical complexity.
3Strength
If a rigid gripping element is used, then the structure is simple and strong, but the force is concentrated at discrete points causing shaft damage
Solution Approach 1:
The elastomeric lining acts as a compliant interface between the rigid gripping element and the shaft. It distributes the gripping and extraction forces across the entire contact surface area rather than concentrating them at discrete points, eliminating the crushing effect while maintaining the structural simplicity and strength of the rigid outer element.
4Ease of operation
If manual pulling is used to extract the arrow, then no special equipment is needed, but excessive user effort is required and extraction may fail
Solution Approach 1:
The slide hammer mechanism generates controlled impact forces (mechanical vibration/shock) that progressively work the arrow shaft loose from the embedded material. Each tap delivers a brief high-force impulse that breaks the bond between the shaft and embedding medium, allowing incremental extraction with minimal sustained user effort.
Solution Approach 2:
The slide weight assembly provides a mechanical advantage system where the user's small tapping force is amplified into large extraction forces on the shaft. The sliding mechanism and weight distribution create a lever-like effect that multiplies the effective extraction force.
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
Enables safe and damage-free retrieval of embedded arrows by distributing force evenly along the shaft, reducing the risk of crushing or bending, and minimizing user effort.
Implementation Method 1
The slide weight is tapped against a slide stop by the user, which, with each subsequent tap, incrementally backs the arrow out of the object
Implementation Method 2
The hemi-cylindrical elements can be lined with an elastomeric material that can have, for example, a Shore A durometer of about 30 to 85
Data Source
AI summary
The shaft removal devices described herein include an elongated gripping portion that allows a shaft, e.g., the shaft of an arrow, to be securely gripped and a force applied in a direction parallel to the long axis of the shaft to be distributed over at least part of the length of the shaft.