Surgical Arm Cam Mechanism for Single-Hand Locking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing arm structures for surgical instruments, such as retractors, require complex manipulation to adjust and lock positions, involving separate actions for bending and fixing, which is cumbersome and inefficient.
Innovation Solution
An arm structure with a cam mechanism that allows sliding, rotation around a vertical axis, and rotation around a horizontal axis, where turning the arm around its axis narrows a slit portion to lock these movements, enabling easy adjustment and fixation by hand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flexible tube with a balled joint and wire is used to allow arm movement, then the arm can be moved in multiple directions, but the adjustment and fixing actions are separate and complex
Solution Approach 1:
The invention merges the adjustment and fixing actions into a single integrated operation. The cam mechanism is designed so that a single rotational movement of the cam simultaneously adjusts the arm position and locks it in place, eliminating the need for separate bending and fixing actions required by the flexible tube with wire system.
Solution Approach 2:
The cam mechanism is designed to automatically lock the arm in position through its own geometric shape and movement. As the cam rotates, its profile automatically engages with the slot in the support member, creating a self-locking mechanism that holds the arm position without requiring additional fixing components or actions.
2Stability of the object's composition
If a string is used to fix the retractor, then the retractor can be secured in position, but moving the retractor requires loosening and re-tightening the string which is troublesome
Solution Approach 1:
The cam mechanism provides dynamic positioning capability where the arm can be easily moved to different positions by simply rotating the cam. The locking and releasing actions are integrated into the same rotational movement, allowing quick repositioning without the troublesome loosening and re-tightening required by string-based fixation systems.
Solution Approach 2:
The invention replaces the string-based fixation system with a cam-based mechanical locking system. The cam's geometric profile and rotational movement provide both secure locking and easy repositioning capabilities, eliminating the need to manually loosen and retighten strings while maintaining positioning stability.
3Adaptability or versatility
If multiple separate mechanisms are used to control arm movements in different directions, then each movement can be controlled, but the device complexity increases
Solution Approach 1:
The cam mechanism serves multiple functions simultaneously: it controls the arm's position, locks the arm in place, and can be operated with a single rotational movement. This multi-functional design eliminates the need for separate mechanisms for each control function, reducing overall device complexity while maintaining full multi-directional control capability.
Solution Approach 2:
The cam's geometric profile is designed with specific parameters that enable it to perform multiple functions. By carefully designing the cam's shape and dimensions, a single rotational movement produces the desired sequence of actions including arm adjustment and locking, thereby controlling multiple degrees of freedom without requiring multiple separate mechanisms.
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
Enables efficient movement and locking of the arm in multiple directions with a single hand manipulation, simplifying the process of positioning and securing surgical instruments like retractors during operations.
Implementation Method 1
a cam provided in the arm, the cam being slidable in a long side direction of the arm and revolving integrally with the arm
Data Source
AI summary
An arm structure includes: a pair of arms; a support post; a support member; a cam provided in one of the pair of arms; a shaft member inserted through a lateral insertion hole of the support member; and a pair of ring-shaped members provided in end portions of the shaft member, wherein by turning the one of the arms around its axis thereby to make the cam revolve, a force works to make the shaft member move, and due to its reaction force the ring-shaped members pressure-contact the support member and a slit portion is narrowed. As a result, a longitudinal insertion hole is diameter-reduced and becomes in a state of pressure-contacting the support post, leading to restriction of rotation of the arm around the support post, and the cam pressure contacts the one of the arms, leading to restriction of sliding of the arm in a long side direction, and the ring-shaped members pressure-contact the support member, leading to restriction of rotation of the arm by the shaft member.