Force Transmission Mechanism With Cylindrical Cam for Constant Efficiency
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Solution Overview
Problem
Existing force transmission mechanisms in instruments, such as those using cables or sliders, face inefficiencies when the joint section is flexed or curved, leading to variable gripping forces and reduced control over end effector movements.
Innovation Solution
A force transmission mechanism with a cylindrical cam mechanism that converts rotational torque into linear force, featuring a cam groove and pin system, which adjusts cam angle, radius, and friction coefficient to maintain constant force transmission efficiency despite joint section flexing or curving, by increasing conversion efficiency with displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a cable or slider is used as a force transmission member, then the structure is simple, but the force transmission efficiency decreases when the joint section is flexed or curved
Solution Approach 1:
The cam mechanism dynamically adjusts the cam angle and contact point between the cam surface and follower based on the displacement amount caused by joint section flexing. This dynamic adaptation allows the mechanism to maintain optimal force transmission efficiency across different joint positions, resolving the contradiction between structural simplicity and transmission reliability.
Solution Approach 2:
The invention changes the cam angle parameter and the contact point parameter on the cam surface according to the displacement amount. By varying these parameters dynamically, the system compensates for the reduced efficiency caused by joint flexing while maintaining a relatively simple overall structure.
2Adaptability or versatility
If the joint section is flexed or curved, then the instrument can reach different positions, but the force transmission efficiency decreases leading to variable gripping forces
Solution Approach 1:
The cam mechanism incorporates a feedback mechanism where the displacement amount caused by joint section flexing is detected and used to adjust the cam angle and contact point. This feedback loop ensures that the gripping force remains consistent despite changes in joint position, maintaining reliability while preserving adaptability.
Solution Approach 2:
The dynamic cam mechanism continuously adjusts its geometry based on real-time displacement, allowing the system to maintain constant force transmission efficiency across the full range of motion of the joint section.
3Reliability
If the cam angle is increased to improve force transmission, then the conversion efficiency increases, but the device complexity increases
Solution Approach 1:
Instead of using a fixed large cam angle that would require a complex mechanism, the invention employs a dynamic cam angle that adapts to the displacement amount. This allows achieving high conversion efficiency through dynamic adjustment rather than through complex static geometry.
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 force transmission to the end effector regardless of joint section angle, allowing precise control over gripping forces and mechanical movements.
Implementation Method 1
A force transmission mechanism with a cylindrical cam mechanism that converts rotational torque into linear force, featuring a cam groove and pin system
Implementation Method 2
adjusts cam angle, radius, and friction coefficient to maintain constant force transmission efficiency
Data Source
AI summary
A force transmission mechanism includes a force adjuster that receives a driving force and that is configured to change a force transmission efficiency, and also includes a driving member that is configured to connect an end effector and the force adjuster via a joint section and transmit the driving force. The force adjuster converts the driving force into a linear force via a rotational force, and increases the conversion efficiency from the driving force to the linear force such that an amount of increase in the force transmission efficiency increases with increasing displacement amount of the driving member when the driving member is displaced in accordance with flexing or curving of the joint section.