Surgical Table Cable Take-Up With Constant Tension and Compact Routing
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Solution Overview
Problem
Existing cable take-up mechanisms in surgical tables fail to provide a constant force or tension throughout the range of motion, are bulky, or require linear movement incompatible with certain table designs, leading to inefficiencies and space constraints.
Innovation Solution
A surgical table incorporating a constant-force spring and sheave mechanism that maintains tension in cables, allowing up to twice the slack variation and enabling cable travel in changing directions, reducing the mechanism's volumetric footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If spring-loaded systems are used to take up cable slack, then the mechanism is simple in structure, but the ability to provide constant force or tension on the cable throughout the range of motion is lost
Solution Approach 1:
The patent employs a curved guide segment that redirects the cable at an angle, creating a mechanical advantage system. This curved geometry transforms the spring's linear force into a more consistent tension force on the cable throughout the range of motion, resolving the contradiction between structural simplicity and force consistency.
2Force
If hydraulic cylinder powered systems are used to take up cable slack, then constant force can be provided, but the size of the cylinder and requirement for fluid pump increase device complexity and space requirements
Solution Approach 1:
The patent utilizes the constant-force spring's inherent properties to automatically take up cable slack without requiring external power sources or control systems. The spring self-regulates the cable tension throughout the range of motion, eliminating the need for hydraulic pumps, cylinders, and associated control mechanisms, thus achieving constant force with reduced complexity.
3Device complexity
If energy chains or sliding groove arrangements are used to take up cable slack, then the mechanism is simple, but linear movement of components is required which is incompatible with surgical tables lacking volumes for such movement
Solution Approach 1:
The curved guide segment enables the cable to change direction without requiring linear movement of the guide itself. This angular redirection mechanism can be mounted on fixed structures, making it compatible with surgical table designs that lack the volume or structural configuration for linear movement components like energy chains or sliding grooves.
4Length of stationary object
If a sheave is added to the cable take-up mechanism, then up to twice as much cable length variation can be accommodated, but the device complexity increases
Solution Approach 1:
The patent integrates the sheave directly into the constant-force spring assembly, combining the cable redirection function with the existing tensioning mechanism. This merged design accommodates up to twice the cable length variation while minimizing additional complexity by reusing the spring's mounting structure and support elements.
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 consistent cable tension and reduces slack, optimizing space utilization by allowing the cable to change paths, thus enhancing the functionality and design flexibility of surgical tables.
Implementation Method 1
a constant-force spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another
Implementation Method 2
a sheave that enables up to twice as much variation in cable length, that is, up to two times as much slack may be taken-up than if no sheave was used
Data Source
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AI summary
A surgical table includes a base, a tabletop, first and second frameworks, a cable, and a cable take-up mechanism. The first and second frameworks are moveable relative to one another to move the tabletop relative to the base in a first direction and a second direction that is opposite the first direction. The cable has a first end, a second end that is opposite the first end, and an intermediate portion. The first and second ends are mounted to the respective first and second frameworks. The cable take-up mechanism includes a constant-force spring coupled to the intermediate portion of the cable to take up slack in the cable as the first and second frameworks move relative to one another to move the tabletop relative to the base.