Rack Arm Counterbalance Cam for Nonlinear Force Control
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Solution Overview
Problem
Movable rack arms in surgical equipment often lack precise control over force transfer, leading to potential disruptions during surgery due to accidental movements.
Innovation Solution
A movable rack arm assembly with a counterbalance spring and a cam mechanism that allows for contoured non-linear force transfer, enabling precise control over the movement of surgical equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a counterbalance spring is used to prevent the rack arm from moving too easily, then stability is improved, but the rack arm becomes difficult to manipulate during surgery
Solution Approach 1:
The cam mechanism transforms the static counterbalance spring force into a dynamic, variable force profile. As the rack arm moves through its range of motion, the cam's eccentric geometry causes the spring force to vary continuously, providing high resistance at certain positions (for stability) and low resistance at others (for ease of manipulation).
Solution Approach 2:
The invention changes the force parameter dynamically along the rack arm's path of motion. The cam groove's contoured shape creates a non-linear force transfer profile, where the magnitude of counterbalance force changes as a function of the rack arm's position, allowing optimization of both stability and manipulability at different points in the motion range.
2Reliability
If a counterbalance spring is used to prevent accidental movements, then safety is improved, but precise control over force transfer is lost
Solution Approach 1:
The cam groove is designed with a specific contoured geometry that precisely controls the force transfer characteristics. By varying the groove's shape, the invention achieves precise control over how spring force is transferred to the rack arm throughout its motion, enabling customized force profiles that enhance both safety and control precision.
Solution Approach 2:
The cam mechanism acts as an intermediary between the counterbalance spring and the rack arm. It mediates the force transfer by transforming the spring's constant force into a variable, position-dependent force through its eccentric geometry, thereby providing precise control over the interaction between the spring and the rack arm.
3Device complexity
If a traditional counterbalance spring is used, then the structure is simple, but the force profile cannot be customized
Solution Approach 1:
The cam mechanism serves multiple functions within a single component: it maintains the counterbalance function of the spring while simultaneously providing force profile customization, motion guidance, and positional control. This multi-functionality allows the system to achieve adaptability without proportionally increasing complexity.
Solution Approach 2:
By changing the geometric parameters of the cam groove (such as its curvature, eccentricity, and contour shape), the invention enables customization of the force profile while maintaining the same basic mechanical structure. This allows adaptation to different surgical applications without redesigning the entire mechanism.
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 provides a customizable force profile that prevents accidental movements while allowing for precise manipulation of surgical equipment, enhancing surgical precision and safety.
Implementation Method 1
The spring assembly includes a spring, a spring arm attached to the spring at a first end
Implementation Method 2
The cam includes a curved cam groove having an inner end and an outer end, wherein the inner end is located radially closer to the axle than the outer end
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
The present disclosure relates to a movable rack arm assembly including a cam housing, a circular gear, a rack arm, a cam, and a spring assembly for contoured non-linear force transfer.