Bone Perforator Cam Re-engagement Mechanism
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Solution Overview
Problem
Existing bone perforators face challenges in maintaining consistent drilling quality across heterogeneous bone tissue structures and in automatically stopping when penetrating the thin inner bone plate to protect the dura mater, with prior solutions experiencing disengagement issues during tissue quality changes or pressure variations.
Innovation Solution
The perforator features a drill head and chipping head connected by a bolt pin with a triangular opening, and a drive shaft with a Hudson cone design, utilizing a first and second connecting profile with abutting and driving surfaces to transmit rotational motion and allow relative displacement, along with a helical groove and spring mechanism for automatic disengagement when the inner bone plate is penetrated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a drill head surrounded by a coaxial chipping head with a triangular opening and bolt pin mechanism is used to automatically stop drilling when the inner bone plate is penetrated, then the dura mater is protected from damage, but the mechanism may lead to disengagement of the drive stem when advancing is interrupted or counter force decreases, making re-engagement difficult
Solution Approach 1:
A cam mechanism acts as an intermediary between the bolt pin and the drive stem, enabling automatic re-engagement. The cam profile is designed such that when the drill head advances, the bolt pin follows the cam surface and automatically re-engages with the drive stem groove without requiring manual intervention, thus solving the re-engagement difficulty while maintaining the protective function
Solution Approach 2:
The system performs self-service through automatic re-engagement. The cam mechanism and bolt pin work together to automatically restore the connection between the drill head and drive stem after disengagement, eliminating the need for manual re-engagement operations and allowing the surgeon to continue drilling without interruption
2Productivity
If substantial pressure is applied to advance the drill head through bone tissue, then drilling progress is achieved, but the drill head must be stopped immediately after penetrating the inner bone plate to prevent damage to the dura mater
Solution Approach 1:
The triangular opening and bolt pin mechanism provide mechanical feedback that automatically detects when the inner bone plate has been penetrated. When the bone plate is penetrated, the counter force decreases, causing the drill head to advance relative to the chipping head, which moves the bolt pin along the cam mechanism to trigger automatic disengagement, thus stopping drilling before dura mater damage can occur
Solution Approach 2:
The system automatically stops drilling upon detecting penetration of the inner bone plate through the mechanical feedback mechanism. The bolt pin and cam mechanism work together to autonomously disengage the drive connection when the stopping condition is met, eliminating the need for manual intervention and ensuring consistent protection of the dura mater
3Manufacturing precision
If the drill head is designed to extend beyond the chipping head to penetrate the cranial bone first, then consistent drilling quality is achieved across different tissue structures, but the mechanism becomes more complex with additional components
Solution Approach 1:
The drill head and chipping head are merged into a single integrated assembly with common rotational axis and coordinated function. Both heads rotate together as a unit, with the drill head extending beyond to perform the initial penetration, while the chipping head provides support and houses the bolt pin mechanism, thus achieving consistent drilling quality without excessive 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
Ensures consistent drilling through different bone tissue structures, automatically stops when penetrating the inner bone plate to protect the dura mater, and prevents disengagement during changes in tissue quality or pressure, facilitating re-engagement and maintaining drilling precision.
Implementation Method 1
a spring mechanism for automatic disengagement when the inner bone plate is penetrated
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a perforator (10) for drilling bone tissue, comprising: - a drive shaft (12) with rotation axis (t), - a drill head (14) with the same rotation axis (t), - a chipping head (16) arranged coaxially around the drill head (14) characterised by that a first connecting profile (20) is provided on a proximal end (18) of the drill head (14), and a second connecting profile (24) is provided on 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) on 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) on 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.