External Fixator Adjustment Tool Pin Orientation
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Solution Overview
Problem
Existing external fixators face challenges in securely and easily varying the distance between bone pins for compression or distraction without losing the angular orientation of the bone pins, as they require loosening of clamping assemblies, which compromises the rigidity of the frame.
Innovation Solution
A separate adjustment tool comprising a fitting element, positioning clamp, and connecting element that securely attaches to the external fixator's clamping assembly, allowing for compression or distraction by moving the clamping assembly along the rod without releasing the bone pin, using a blocking sleeve and actuation mechanism to maintain pin orientation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the clamping assembly is loosened to adjust the distance between bone pins, then the distance can be varied, but the angular orientation of the bone pin is lost
Solution Approach 1:
The patent introduces a blocking sleeve as an intermediary component that mediates between the adjustment operation and the bone pin orientation. The blocking sleeve can be selectively positioned to block the movement of the bone pin while allowing the clamping assembly to be loosened and adjusted, thus preserving the angular orientation during the adjustment process
2Reliability
If a separate adjustment tool is introduced to maintain bone pin orientation, then the angular orientation is preserved, but the device complexity increases
Solution Approach 1:
The blocking sleeve is designed with multi-functionality: it can block the bone pin to maintain orientation, it can be actuated by the existing actuation element within the clamping assembly, and it integrates with the fitting element that already exists in the clamping assembly structure. This universal design minimizes the addition of separate components while achieving the orientation preservation function
3Ease of operation
If the clamping assembly is loosened for compression or distraction, then the adjustment can be made, but the rigidity of the frame is compromised
Solution Approach 1:
The patent implements a dynamic system where the blocking sleeve can be selectively engaged or disengaged. During adjustment operations, the blocking sleeve is engaged to maintain rigidity while allowing controlled movement. When the adjustment is complete, the blocking sleeve can be disengaged to allow final tightening, thus providing dynamic adaptability between rigidity and adjustability
Data Source
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Figure 3
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AI summary
An adjustment tool (10) for an external fixator for exerting a compression or distraction on a broken bone fixed by bone pins (2) spanned over such a fracture comprises: a fitting element (12) for holding fast a clamping assembly (3) of the external fixator, a positioning clamp (11) for fixing the adjustment tool on a rod (1) of the external fixator near said clamping assembly (3), and a connecting element (13) attached to the fitting element (12) and the positioning clamp (11) adapted to move the fitting element (12) towards to or away from the positioning clamp (11). The fitting element (12) comprises a blocking sleeve (122) adapted to push the uppermost jaw of the clamping assembly (3) in the direction of the longitudinal axis of the clamping assembly (3) to block the second upper most jaw against an abutment portion (129) of the fitting element (12) and further comprises an actuation element (123) within the blocking sleeve (122) to actuate the locking element of the clamping assembly (3) for releasing the rod (1) of the external fixator within the clamping assembly (3) without releasing the bone pin (3).