Surgical Saw Blade Lock Teeth for Backlash-Free Coupling
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Solution Overview
Problem
Surgical sagittal saws and blades experience blade slap and backlash due to misalignment, leading to component fatigue, reduced cutting efficiency, and precision issues, as well as blade deformation when used with resection guides, necessitating improved attachment mechanisms to ensure the saw head and blade move as a single unit.
Innovation Solution
The surgical saw and blade design incorporates lock teeth made of softer material that deform upon compression, securing the blade to the saw head with an anvil and press, eliminating clearance and ensuring synchronized movement between the saw head and blade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the blade is provided with clearance in the saw head slot to facilitate easy insertion and removal, then the ease of operation is improved, but the blade moves independently of the saw head causing blade slap and backlash
Solution Approach 1:
The lock teeth are designed to be deformable rather than rigid, allowing them to dynamically adapt to the slot dimensions. The teeth deform under compression to lock the blade securely, then return to their original shape when the press force is released, enabling easy blade removal while maintaining reliable synchronization during operation.
Solution Approach 2:
The physical state of the lock teeth changes from a relaxed state (allowing blade removal) to a compressed deformed state (locking blade securely). This parameter change in the teeth's shape and position enables the system to transition between ease of operation and reliable synchronization modes.
2Reliability
If the blade is tightly fitted in the saw head slot to eliminate movement, then the blade-saw head synchronization is improved, but the ease of blade insertion and removal deteriorates
Solution Approach 1:
The lock teeth transition from a rigid fixed position to a deformable dynamic state, allowing the blade to be inserted easily while maintaining tight synchronization during operation. The teeth deform under compression to eliminate clearance, then return to their original shape when the blade needs to be removed.
Solution Approach 2:
The press applies compression force to the lock teeth before the blade is fully inserted, pre-deforming the teeth to create a secure lock. This preliminary action ensures synchronization is established before the blade begins cutting, while the deformable nature allows easy removal when the press force is released.
3Strength
If the lock teeth are made of hard material to resist wear, then the strength is improved, but the ability to deform and lock into the slot deteriorates
Solution Approach 1:
The lock teeth are made of softer material specifically at the locking surfaces that contact the slot, while other parts of the blade can be harder. This local quality difference allows the teeth to deform and lock securely into the slot while maintaining adequate strength for the cutting function.
Solution Approach 2:
The blade assembly uses composite construction with lock teeth made of a softer, more ductile material compared to the harder cutting portion of the blade. This material differentiation allows each component to have the optimal properties for its specific function: deformability for locking, hardness for cutting.
4Reliability
If the blade and saw head move in complete unison to eliminate blade slap, then the reliability is improved, but the complexity of the attachment mechanism increases
Solution Approach 1:
The lock teeth automatically deform and lock into the slot under the action of the press, without requiring external adjustment or complex actuation mechanisms. The teeth self-adjust to eliminate clearance and ensure synchronization, reducing the overall complexity of the attachment mechanism while improving reliability.
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 design eliminates blade slap, backlash, and deformation, enhancing cutting precision and efficiency by ensuring the blade moves in unison with the saw head, reducing wear on components and improving the accuracy of bone cuts.
Implementation Method 1
The lock teeth are formed from material that, in comparison to the material from which the blade body and cutting teeth are formed, is relatively soft. The press is moved against the blade... As a result of this compression of the blade, the press surfaces push the lock teeth into the slots formed in the anvil or the press. As a result of this deformation of the blade lock teeth, there is essentially no clearance between the lock teeth and the anvil and the press
Data Source
AI summary
A surgical saw includes a body, a coupling assembly, and a motor. The coupling assembly is mounted to the body and adapted to releasably hold a saw blade. The coupling assembly includes an anvil, a press, and a clamping assembly. The anvil has a channel or a press foot. The press has the other of the press foot and the channel. The press foot is receivable by the channel. The clamping assembly selectively moves the press and the anvil towards and away from each other. When the press is brought towards the anvil, the press foot may press a lock tooth of the saw blade into the channel so that the lock tooth is compressed between the anvil and the press to coin the lock tooth. The motor, internal to the body, is connected to the coupling assembly to reciprocate the coupling assembly and the saw blade.