Cartridge Delivery Piston Locking Mechanism for Bone Cement
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Solution Overview
Problem
Existing bone cement mixing and dispensing systems face challenges with air pockets formation due to complex locking mechanisms and structural weaknesses, leading to potential destabilization and mechanical property issues in the hardened cement.
Innovation Solution
A cartridge system with a delivery piston featuring a simple, manually unlockable locking device on the delivery piston, which includes latching means accessible from the outside, allowing easy operation without loose parts or external tools, and a design that enhances structural stability by eliminating recesses that could weaken the cartridge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex locking mechanism is used to secure the delivery piston, then the delivery piston is reliably locked during mixing, but the mechanism becomes difficult to unlock manually and may require external tools or loose parts
Solution Approach 1:
The locking mechanism is segmented into a locking element integrated with the delivery piston and a separate cartridge body. The locking element can be manually actuated through a cavity in the cartridge wall, separating the locking function from complex external mechanisms while enabling manual operation.
Solution Approach 2:
The locking element is designed to be self-actuating through manual compression via the cavity. The user can directly manipulate the locking element through the cavity without requiring external tools or complex unlocking mechanisms, making the system self-sufficient for manual operation.
2Reliability
If recesses are provided in the cartridge wall for locking means, then the delivery piston can be securely locked, but the cartridge structure becomes weaker and more prone to breakage
Solution Approach 1:
Instead of providing recesses throughout the cartridge wall, a localized cavity is provided at a specific position. This cavity is sufficiently large to receive the locking element but is strategically positioned to minimize impact on the overall structural strength of the cartridge, balancing locking functionality with structural integrity.
3Ease of operation
If the delivery piston is easily unlocked manually, then operation is simple and cost-effective, but the locking mechanism may become less stable and reliable
Solution Approach 1:
The locking element is merged with the delivery piston as an integrated component rather than a separate mechanism. This integration ensures that the locking and delivery functions are coordinated, maintaining locking stability while enabling simple manual operation through the cavity.
4Reliability
If vacuum mixing is used to remove air pockets, then the mechanical properties of the hardened cement are improved, but the complexity of the mixing system increases
Solution Approach 1:
The cavity is designed to be filled with vacuum before the locking element is inserted. This preliminary vacuuming action removes air pockets from the cement mixture before mixing begins, improving cement quality without requiring complex continuous vacuum mixing systems throughout the entire process.
Data Source
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AI summary
The cartridge (80) has a cylindrical cavity bordered by a cartridge wall (92), and a delivery piston (81) movably arranged in the cavity along the cylinder axis of the cavity and a locking unit (66), with which the delivery piston is lockable at the cartridge wall. A locking device (85) is arranged at the delivery piston, which has one of the locking units and is accessible from out side during locking of the delivery piston. Independent claims are also included for the following: (1) a cartridge system for preparing a mixture, particularly cement; and (2) a method for injecting a cartridge content.