Bone Fixation Strut Locking Assembly for Stable Adjustment
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Solution Overview
Problem
External bone fixation devices are susceptible to loosening due to varying pressures and forces, affecting the positioning and spacing of distraction and reduction/compression devices, and are prone to inadvertent contact that can disrupt the adjustment process during bone healing.
Innovation Solution
A strut assembly with a sleeve, rod, actuator, and lock member that allows for precise adjustment and locking mechanisms to maintain the desired orientation and spacing of bone fixation members, including a lock member that transitions between locked and unlocked positions to prevent or allow rotation between the sleeve and actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If distraction and reduction/compression devices are used to adjust bone segments, then the positioning and spacing of bone fixation members can be modified, but the devices are susceptible to loosening due to varying pressures and forces
Solution Approach 1:
The locking mechanism transitions between locked and unlocked states, allowing the system to dynamically switch between adjustable and fixed configurations. The lock member can engage with the sleeve to prevent rotation during healing, then be disengaged for adjustment when needed.
Solution Approach 2:
The lock member acts as an intermediary element between the sleeve and actuator, mediating the connection between these components. When engaged, it transfers and maintains the positional relationship; when disengaged, it allows for modification of this relationship.
2Duration of action of stationary object
If the distraction and reduction/compression device is held fixed after adjustment, then bone healing can occur, but inadvertent contact can still adversely affect the adjustment
Solution Approach 1:
The lock member is engaged in advance to prevent inadvertent contact and adjustment changes before any harmful effect can occur. This preliminary locking action ensures that the device remains fixed during the entire healing period.
Solution Approach 2:
The locking mechanism applies a counter-action to prevent inadvertent contact from affecting the adjustment. By engaging the lock member, the system creates a protective constraint that opposes any external forces that might cause loosening.
3Reliability
If the lock member engages both the sleeve and the actuator, then relative rotation between actuator and rod is prevented, but the device complexity increases
Solution Approach 1:
The lock member combines multiple functions into a single component: it engages with both the sleeve and actuator, prevents relative rotation, and maintains the positional relationship between these parts. This merging reduces the need for separate locking components.
Solution Approach 2:
The lock member serves multiple purposes: it acts as a rotational constraint, a positional maintainer, and a connection element between the sleeve and actuator. This multi-functionality reduces the overall device complexity despite the added locking 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
The strut assembly provides stable and precise adjustment of bone fixation devices, minimizing loosening and maintaining the desired positioning and spacing of bone segments for effective bone healing.
Implementation Method 1
The rod has a threaded outer surface and extends through the sleeve bore along the strut axis such that the rod is translatable relative to the sleeve along the strut axis
Implementation Method 2
The lock member is configured to transition between a locked position in which the lock member engages both the sleeve and the actuator so as to prevent relative rotation between the actuator and the rod
Data Source
AI summary
An strut assembly extends along a strut axis and comprises a strut body, an actuator, and a locking assembly. The strut body includes a rod and a sleeve. The rod is translatable relative to the sleeve along the strut axis. The actuator is linearly engaged with the sleeve such that linear movement of the actuator causes linear movement of the sleeve. The locking assembly includes a lock member configured to transition between a locked position in which the lock member engages both the sleeve and the actuator such that rotation between the sleeve and the actuator is substantially prevented, and an unlocked position in which the lock member is spaced apart from the sleeve such that the actuator is substantially free to rotate about the sleeve.