Adjustable Tibial Trial Insert With Synchronized Scissor Lifts
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Solution Overview
Problem
Existing adjustable tibial trial inserts suffer from adjustment-related deformations of the upper plate and upper articular surface, lacking stability during gap adjustments between the upper and lower plates.
Innovation Solution
The solution involves kinematically coupling the second scissor lift mechanism to the first scissor lift mechanism through a coupling element, allowing synchronous variation of the lever arm arrangements, thereby preventing deformations and enhancing stability by eliminating separate actuators from the second mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate actuator bolts are used for each scissor lift mechanism, then independent adjustment capability is achieved, but adjustment-related deformations and instability occur
Solution Approach 1:
The patent combines the adjustment functions of multiple scissor lift mechanisms into a single integrated system. One actuator element controls multiple scissor lift mechanisms through a common actuation line, ensuring synchronized movement and eliminating independent adjustment capabilities that cause instability. This merging approach maintains reliable and stable gap adjustment while preventing the deformations associated with separate actuators.
2Ease of operation
If multiple separate actuators are provided for each scissor lift mechanism, then comprehensive control is achieved, but device complexity and risk of deformation increase
Solution Approach 1:
The single actuator element is designed to perform multiple functions simultaneously by controlling several scissor lift mechanisms through a shared actuation line. This multi-functional approach provides comprehensive control over the gap adjustment while reducing the total number of actuators, thereby simplifying the device structure and eliminating the complexity associated with multiple separate actuators.
3Adaptability or versatility
If the second scissor lift mechanism includes a separate actuator element, then independent adjustment is possible, but unintentional deformation or damage may occur
Solution Approach 1:
The patent extracts the actuator element from the second scissor lift mechanism, eliminating the source of independent adjustment that leads to deformation and damage. Instead, the second mechanism is passively controlled through the actuation line connected to the first mechanism's actuator, ensuring synchronized movement and preventing harmful independent adjustments while maintaining the necessary adaptability.
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 configuration prevents unintentional deformations and damage to the upper plate and articular surface while ensuring stable and precise adjustment of the gap between the upper and lower plates, improving the overall stability and simplicity of the adjustment mechanism.
Implementation Method 1
The coupling element is connected to both the first scissor lift mechanism and the second scissor lift mechanism and produces a force and motion transmitting connection and/or coupling
Implementation Method 2
each adjustor comprises a scissor lift mechanism... an actuation of the actuator element of the first scissor lift mechanism causes not only a variation of the length of the first lever arm arrangement, but at the same time a synchronous variation of the length of the second lever arm arrangement
Data Source
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AI summary
Adjustable tibial trial insert (1), comprising: an upper plate (2) including an upper articular surface (21) configured for articulation with a femoral surface; a lower plate (3) positioned below the upper plate along an adjustment axis (Z) and including a lower surface (31) configured for tibial fixation; an adjustment arrangement (A) arranged between the upper plate and the lower plate and actuatable for adjustment of a gap (G) between the upper plate and the lower plate along the adjustment axis; wherein the adjustment arrangement comprises at least a first scissor lift mechanism (4) with a first lever arm (40 - 47) arrangement and a separate second scissor lift mechanism (5) with a second lever arm arrangement (50 - 57), wherein each of the lever arm arrangements is at least indirectly connected to the upper plate and the lower plate, and wherein each of the lever arm arrangements is pivotally movable between different positions for variation of its length along the adjustment axis in order to adjust the gap between the upper plate and the lower plate; characterized in that the first scissor lift mechanism comprises an actuator element (48) coupled to the first lever arm arrangement and configured such that actuation of the actuator element varies the length of the first lever arm arrangement; and in that the adjustment arrangement comprises at least one coupling element (6, 6') coupling the second scissor lift mechanism to the first scissor lift mechanism and configured such that the length of the second lever arm arrangement is varied synchronously to the first lever arm arrangement.