Perforator Assembly Magnetic Disengagement Mechanism
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Solution Overview
Problem
Existing perforator assemblies for bone tissue face challenges in maintaining consistent drilling quality across non-homogeneous bone structures and ensuring the drill head stops before penetrating the dura mater, due to the linear displacement dependence of spring force and increased complexity with additional structural elements.
Innovation Solution
A perforator assembly with a drive shaft, drill head, and chipping head connected via a bolt pin and cooperating connecting profiles, utilizing a magnetic repelling mechanism to facilitate disengagement and ensure precise stopping of the drill head within the internal bone plate, reducing the number of separate pieces and simplifying assembly and cleaning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a biasing spring is used to disengage the drill head from the drive shaft, then the drill head can be disengaged automatically after penetrating the bone, but the cutting motion becomes unbalanced and the assembly complexity increases
Solution Approach 1:
The patent removes the biasing spring and security spring from the assembly, extracting the problematic mechanical components that caused unbalanced cutting motion and assembly complexity. The automatic disengagement function is replaced by a purely geometric mechanism involving the wedge-shaped disengagement surface and the resilient means already present in the drill head, eliminating the need for additional springs and reducing assembly complexity.
Solution Approach 2:
The patent segments the disengagement mechanism into distinct functional elements: the wedge-shaped disengagement surface on the drive shaft, the corresponding recess in the drill head, and the resilient means. This segmentation allows each element to perform its specific function independently, improving the balance of cutting motion while maintaining automatic disengagement capability.
2Stability of the object's composition
If additional structural elements like security springs are added to balance the cutting motion, then the drilling process becomes more balanced, but the number of pieces increases and cleaning becomes more difficult
Solution Approach 1:
The patent removes the security spring and biasing spring from the assembly, extracting the additional structural elements that made cleaning difficult. The cutting motion balance is achieved through the optimized geometric relationship between the wedge-shaped disengagement surface, the recess, and the resilient means, eliminating the need for separate spring components that would require disassembly for cleaning.
Solution Approach 2:
The patent merges the functions of the biasing spring and security spring into the existing resilient means already integrated into the drill head structure. This consolidation reduces the total number of pieces and eliminates the need for separate spring assemblies, thereby simplifying the cleaning process while maintaining the stability of the cutting motion.
3Productivity
If the drill head is designed to penetrate through dense bone plates, then effective drilling is achieved, but the risk of penetrating the dura mater increases if stopping precision is not maintained
Solution Approach 1:
The patent implements a feedback mechanism through the wedge-shaped disengagement surface that automatically responds to changes in drilling resistance. When the drill head penetrates the dense inner bone plate, the reaction force changes, causing the drill head to move along the wedge surface and engage the disengagement mechanism, which automatically stops the drive shaft's rotational transmission. This provides real-time feedback-based control to prevent dura mater penetration while maintaining effective drilling through dense bone.
Solution Approach 2:
The patent employs a dynamic disengagement mechanism where the resilient means and wedge-shaped surface work together to automatically adjust the engagement between the drive shaft and drill head based on real-time drilling conditions. This dynamic system allows the drill to effectively penetrate dense bone plates while automatically stopping when the drill head encounters the transition to softer tissue, thereby preventing harmful penetration of the dura mater.
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 magnetic repelling mechanism provides a more efficient and balanced drilling process with a steeper force decay rate, ensuring the drill head stops before penetrating the dura mater, and simplifies the assembly and cleaning of the perforator assembly by reducing the number of pieces and complexity.
Implementation Method 1
utilizing a magnetic repelling mechanism to facilitate disengagement and ensure precise stopping of the drill head within the internal bone plate
Data Source
Figure 1a
Figure 1b
Figure 2a~2c
AI summary
The invention relates to a perforator assembly (10) for drilling bone tissue, comprising a drive shaft (12) having a rotation axis (t), a chipping head (16) having the same rotation axis (t), a drill head (14) arranged coaxially inside the chipping head (16); a first connecting profile (20) is provided at a proximal end (18) of the drill head (14), and a second connecting profile (24) is provided at a distal end (22) of the drive shaft (12), and the drill head (14) is arranged so as to be displaceable with respect to the chipping head (16) along the rotation axis (t) between a proximal position and a distal position, and in the proximal position the second connecting profile (24) at the distal end (22) of the drive shaft (12) cooperates with the first connecting profile (20) such as to transmit rotational motion from the drive shaft (12) to the drill head (14), and in the distal position the first connecting profile (20) at the proximal end (18) of the drill head (14) and the second connecting profile (24) on the distal end (22) of the drive shaft (12) are disengaged characterised by that a first magnet (54a) is arranged in a closed off cavity (50) at the proximal end (18) of the drill head (14), and a second magnet (54b) is arranged in a closed off cavity (52) at a distal end (22) of the drive shaft (12) such that same magnetic poles are facing each other.