External Fixation Ball Collet Clamp with Splined Rod
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Solution Overview
Problem
Existing external fixation systems for bone fractures lack precision and stability in pin placement and alignment, particularly in providing an independent range of motion for each pin and preventing axial rotation of clamps, which can complicate the healing process and require prolonged pin retention.
Innovation Solution
The system incorporates ball collets and a splined connecting rod, allowing for independent pin placement with enhanced accuracy and preventing axial rotation between clamps, enabling precise alignment and movement of pins through a drive screw mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional external fixation systems use simple pin clamps without independent motion capability, then the device structure is simpler, but pin placement precision and alignment stability deteriorate
Solution Approach 1:
The clamp assembly is divided into independent components: a fixed clamp, a movable clamp, and a drive screw mechanism. Each clamp can independently adjust and secure pins, allowing precise pin placement while maintaining overall structural organization through modular segmentation.
Solution Approach 2:
The movable clamp is designed to be dynamically adjustable relative to the fixed clamp through the drive screw mechanism. This dynamic capability allows the clamps to adapt to different pin positions and angles, enhancing pin placement precision without requiring an entirely complex static structure.
2Stability of the object's composition
If clamps are connected without preventing axial rotation, then the connection structure is simpler, but alignment stability and pin placement accuracy deteriorate
Solution Approach 1:
A connecting rod serves as an intermediary element between the fixed clamp and movable clamp. This connecting rod incorporates splines that act as a mechanical mediator to prevent axial rotation while allowing controlled movement, thereby stabilizing clamp alignment without requiring an overly complex direct connection.
Solution Approach 2:
The connection between clamps replaces a simple mechanical link with a splined connecting rod mechanism. The splines substitute for a more complex rotational restraint system, preventing axial rotation through geometric interlocking rather than through additional active mechanical components.
3Adaptability or versatility
If pins are fixed without independent range of motion capability, then the fixation structure is simpler, but pin placement precision and adaptability deteriorate
Solution Approach 1:
Each pin clamp is segmented into independent components including a ball collet, collet cap, and associated mounting mechanisms. This segmentation allows each pin to be independently adjusted and secured, providing adaptability in pin placement while keeping individual clamp units relatively simple in structure.
Solution Approach 2:
The ball collet uses a spherical geometry to accommodate pins with varying orientations. This spheroidality allows the pin to be inserted and secured at different angles while maintaining a compact clamp structure, enhancing adaptability without significantly increasing complexity.
4Reliability
If prolonged pin retention is used to ensure stability, then fixation reliability improves, but treatment duration and patient comfort deteriorate
Solution Approach 1:
The clamps and pins are designed with preliminary adjustment capabilities, allowing precise initial placement and secure fixation from the outset. This preliminary action ensures immediate stability, reducing the need for prolonged retention and allowing earlier removal while maintaining fixation reliability.
Solution Approach 2:
The drive screw mechanism allows dynamic adjustment of clamp positions and pin tensions during the healing process. By changing mechanical parameters such as clamp spacing and pin securement force, the system can maintain reliability while enabling earlier removal compared to static fixation systems requiring prolonged retention.
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 enhances the precision and stability of pin placement, allowing for independent motion of each pin and preventing clamp rotation, thereby facilitating effective bone alignment and healing while reducing the need for prolonged pin retention.
Implementation Method 1
a drive screw, a connecting rod, a cap clamp having a first hole for receiving the upper end of the drive screw therethrough
Implementation Method 2
The connecting rod is preferably splined to provide excellent transport geometry and prevent the movable and fixed clamps from axial rotation relative to each other
Implementation Method 3
A first ball collet is pivotably mounted within the movable clamp first opening, wherein the first ball collet is secured within the movable clamp first opening by a first collet cap
Implementation Method 4
The collet caps are tightened to compress the ball collets and thereby secure the pins within the ball collets
Data Source
AI summary
An external fixation system having at least one ball collet pivotably mounted within a movable clamp and at least one ball collet pivotably mounted within a fixed clamp, wherein a surgical pin is mounted within each ball collet. In operation, the surgical pins are screwed into bone and passed through openings through the fixed clamp, movable clamp, and ball collets. A drive knob is operable to rotate a drive screw and thereby move the movable clamp either towards or away from the fixed clamp and concomitantly move the pins secured in the movable clamp either towards or away from the pins secured in the fixed clamp. A connecting rod prevents axial rotation of the movable clamp and fixed clamp relative to each other.