Bone Anchoring Device Independent Angular Position Indication
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Solution Overview
Problem
Existing bone anchoring devices require interaction between the head and the receiver member to indicate a special angular position of the shank, which can be cumbersome and dependent on the clamping mechanism.
Innovation Solution
A bone anchoring device with an anchoring element having a shank and a head, where the receiving part is configured to receive the head in a pivotable manner, and a pressure member that exerts pressure on the head to clamp it, while providing a position indication structure on the head and pressure member to indicate the predetermined angular position of the shank relative to the receiving part.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the head and receiver member interact to indicate the angular position, then the angular position can be indicated, but the indication becomes cumbersome and dependent on the clamping mechanism
Solution Approach 1:
The position indication function is segmented from the clamping mechanism. The receiver member has a first position indication structure and the pressure member has a second position indication structure, allowing independent indication functionality separate from the clamping action. This enables the angular position to be indicated without relying on the interaction between head and receiver member during clamping.
Solution Approach 2:
Position indication structures act as intermediaries between the clamping mechanism and the user. These structures provide tactile or audible feedback through geometric features (such as cam profiles or asymmetric shapes) that indicate angular position without requiring direct interaction between the head and receiver member, thereby simplifying the alignment operation.
2Measurement precision
If the compression cap position is coupled to the shank position, then the angular position can be indicated, but the system becomes more complex
Solution Approach 1:
The pressure member serves multiple functions: it applies clamping force to secure the head in the receiver member, and simultaneously provides position indication through its second position indication structure. This multi-functionality eliminates the need for separate indication mechanisms, reducing overall device complexity while maintaining accurate angular position indication.
Solution Approach 2:
The position indication structures are merged into the existing clamping components. The first position indication structure is formed on the receiver member and the second on the pressure member, combining the indication function with the clamping mechanism rather than adding separate independent systems, thereby avoiding increased complexity.
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
Facilitates easier alignment of the receiving part relative to the shank by providing a tactile or audible feedback when the predetermined angular position is reached, allowing for independent indication of the angular position from the clamping mechanism.
Implementation Method 1
a section configured to encompass the head in such a manner that the head is held by friction in the head receiving recess
Data Source
AI summary
A bone anchoring device includes an anchoring element having a shank and a head, a receiving part configured to pivotably receive the head, and a pressure member defining a head receiving recess for pivotably holding the head and having a portion configured to extend to a side opposite a free end of the head and to exert pressure on the side opposite the free end to clamp the head in the receiving part. The head has a first position indication structure configured to engage a second position indication structure of the pressure member when the shank assumes a first angular position, and to disengage from the second position indication structure when the shank is at an angular position different from the first angular position. The second position indication structure is engageable with the first position indication structure without protruding into a profile defined by the head receiving recess.