Torque-Limited Knob Assembly for Circular Stapler
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Solution Overview
Problem
Existing circular staplers can cause excessive compression of tissues during the anastomosis process due to continued rotation of the knob assembly beyond the desired position, potentially leading to tissue damage.
Innovation Solution
A knob assembly with a screw rod and elastic cooperating components that prevent further rotation when a preset resistance value is reached, ensuring the anvil assembly remains in the correct position relative to the cartridge, thereby preventing excessive tissue compression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the knob assembly allows continuous rotation to move the anvil assembly towards the cartridge, then the anastomosis operation can be completed, but the tissues may be excessively compressed or crushed
Solution Approach 1:
The patent changes the mechanical parameter of torque transmission by introducing a friction-based torque limiting mechanism. When the knob is rotated, the torque is limited to a preset value through friction between the knob driver and knob body, preventing excessive torque transmission that would cause tissue crushing. This parameter change transforms the continuous rotation capability into a controlled torque-limited operation.
Solution Approach 2:
The patent implements a feedback mechanism where the friction between the knob driver and knob body provides real-time resistance feedback to the operator. When the preset torque is reached, the increased friction resistance gives tactile feedback to the operator, indicating that the anvil assembly has reached the appropriate position relative to the cartridge, thus preventing excessive compression.
2Productivity
If the knob assembly transmits large torque to move the anvil assembly quickly, then the operation speed increases, but the tissues may be damaged
Solution Approach 1:
The patent changes the torque parameter from uncontrolled to controlled by introducing friction-based torque limiting. The friction between the knob driver and knob body automatically limits the torque to a preset safe value, ensuring that the anvil assembly moves at a controlled speed that prevents tissue damage while still maintaining operational efficiency.
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 solution effectively prevents excessive tissue compression by engaging a failure mode when the preset resistance is met, maintaining the anvil assembly's position and ensuring precise surgical outcomes.
Implementation Method 1
the first cooperating component is an elastic sheet having two ends and a protruding portion between the two ends; when the first cooperating component is in the blocking state, the first cooperating component and the second cooperating component are fixedly linked with each other, when a rotating resistance to the knob body is larger than a preset resistance value, the elastic sheet is deformed by a force of the second cooperating component and enters the unblocking state
Data Source
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AI summary
Provided are a knob assembly and round tube type stapler; the knob assembly comprises a knob drive member and a knob body (1) which are optionally linked for concomitant motion; the knob body (1) is sleeved on the outside of a screw rod (6), and when the knob body (1) rotates, the screw rod (6) moves in the axial direction of the stapler; one of a first fitting member and a second fitting member is arranged on the knob drive member and the knob body (1), respectively; the first fitting member is an elastic fitting member and the first fitting member has a blocking state and a yielding state; when the first fitting member is in the blocking state, the first fitting member moves concomitantly with the second fitting member; when the first fitting member is in the yielding state, the first fitting member does not move concomitantly with the second fitting member. By means of using the knob assembly, when the knob drive member is rotated, and after the resistance to which the knob body (1) is subjected reaches a preset resistance value, the knob assembly is no longer able to transmit a larger torque, and at such time, the knob assembly enters a failure mode; the gap between a staple anvil assembly (83) and a staple compartment assembly (82) remains unchanged and does not cause tissue to be pressed excessively.