Surgical Bone Punch Spring Force Adaptation
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Solution Overview
Problem
Surgical bone punches with pneumatic drives face challenges in adapting forward displacement forces to differently dimensioned units, leading to potential damage or injury due to excessive cutting forces, especially when switching between units with varying cutting edge widths.
Innovation Solution
Incorporating an elastic spring element on the stationary shaft that counteracts the forward displacement force of the motorized drive only after a portion of the displacement path is reached, allowing for adjustable reduction of the force to match the cutting edge dimensions, ensuring consistent and optimal force application without operator intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the forward displacement force of the motorized drive is kept constant and full, then the drive supplies sufficient force for all units, but excessively high forces damage narrow cutting edges or injure tissue
Solution Approach 1:
The patent applies dynamics by making the forward displacement force variable rather than constant. An elastic spring element is introduced that dynamically adjusts the force applied to the cutting edge based on the displacement distance. The spring gradually reduces the force from the motorized drive as the slide shaft moves from proximal to distal position, ensuring high initial force for engagement and reduced force near the end to prevent damage to narrow cutting edges or tissue injury.
Solution Approach 2:
The patent changes the force parameter during operation. The elastic spring element modifies the force characteristic of the motorized drive by introducing a progressive reduction. The spring constant and pre-compression can be selected to achieve the desired force profile, transforming the constant force output of the motorized drive into a variable force that adapts to the cutting edge dimensions and prevents harmful effects.
2Object-affected harmful factors
If the forward displacement force is reduced for narrow cutting edges, then damage is prevented, but insufficient force reduces cutting effectiveness for wider units
Solution Approach 1:
The dynamic force adjustment via the elastic spring ensures that full motorized drive force is available at the beginning of the stroke for effective cutting engagement, especially for wider units requiring higher forces. As the displacement progresses and the cutting edges approach, the spring progressively reduces the force to prevent damage to narrow cutting edges, thus maintaining both cutting effectiveness and safety throughout the operation.
Solution Approach 2:
The elastic spring is pre-configured with specific dimensions and pre-compression to establish the appropriate force reduction characteristic before operation begins. This preliminary setup ensures that the force profile is automatically optimized for the specific unit configuration without requiring operator intervention or switching of components.
3Adaptability or versatility
If operators switch between different units with varying cutting edge widths, then adaptability is achieved, but the complexity of switching and risk of incorrect force settings increases
Solution Approach 1:
The system performs self-adjustment of the forward displacement force through the elastic spring element. When a unit with stationary shaft and slide shaft is mounted on the handgrip, the corresponding elastic spring is automatically positioned and configured to provide the appropriate force reduction characteristic. This eliminates the need for operators to manually switch force settings or valves, as the system self-adapts to the mounted unit dimensions.
Solution Approach 2:
The elastic spring element acts as an intermediary between the motorized drive and the cutting edge. It mediates the force transmission by progressively reducing the motorized drive's output force according to the displacement position, automatically compensating for variations in cutting edge width without requiring operator intervention or complex switching mechanisms.
4Power
If the elastic spring element counteracts the forward displacement force only after a portion of the displacement path, then full force is available for initial engagement, but the spring must be precisely positioned to activate at the correct moment
Solution Approach 1:
The elastic spring is pre-configured during manufacturing with specific dimensions, pre-compression, and positioning features that ensure it activates at the correct displacement point. The receiving chamber in the stationary shaft and the stop on the slide shaft are designed to automatically position the spring at the appropriate location, eliminating the need for complex adjustment mechanisms during assembly.
Solution Approach 2:
The elastic spring's progressive engagement creates a dynamic force profile where full motorized drive force is available during the initial portion of displacement for effective cutting engagement. As the slide shaft continues to move and the cutting edges approach, the spring gradually engages and reduces the force, providing a smooth transition that prevents damage while maintaining cutting effectiveness.
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 solution allows for automatic adaptation of forward displacement forces to match the unit's dimensions, reducing the risk of damage or injury by providing a controlled and optimal force application, ensuring the motorized drive maintains a constant full force while reducing it as needed for each cutting edge, thus enhancing safety and efficiency.
Implementation Method 1
the slide shaft carries a stop, which, during displacement of the slide shaft to the operative position, strikes an elastic spring element, which is supported on the stationary shaft, and, during displacement of the slide shaft, counteracts the forward displacement force of the drive
Data Source
AI summary
In a surgical bone punch having a stationary shaft joined to a handgrip, a slide shaft mounted for longitudinal displacement on this stationary shaft, and a motorized drive in the handgrip for displacement of the slide shaft from a proximal inoperative position to a distal operative position with a preset forward displacement force, in order to control the effective forward displacement force of the slide shaft, it is proposed that the slide shaft carry a stop, which, during displacement of the slide shaft to the operative position, strikes an elastic spring element, which is supported on the stationary shaft, and, during displacement of the slide shaft, counteracts the forward displacement force of the drive.