Rotational Overtravel Protection for Cable Twist Limits
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Solution Overview
Problem
Existing connectors used to transmit electrical power and data between stationary and rotating parts within assemblies suffer from line loss and mechanical limitations, such as cable twisting damage, necessitating a solution to prevent rotational overtravel.
Innovation Solution
A rotational overtravel protection device comprising a housing, a rotatable shaft, a triggering device with a pawl and protrusion mechanism, and first and second rotational limit switches, which prevent overrotation by activating the switches when the shaft rotates beyond 180 degrees in either direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a connector is used to transmit electrical power and data from a stationary part to a rotating part, then power and data transmission is enabled, but line loss occurs which is unacceptable for system functionality
Solution Approach 1:
The patent replaces the electrical connector system with a mechanical cable system that twists along with relative rotation. This substitution eliminates the line loss inherent in electrical connectors while maintaining the ability to transmit power and data through the cable itself, directly resolving the contradiction between reliability and energy loss.
2Loss of energy
If a cable is used between moving parts to avoid line loss, then energy transmission efficiency is improved, but the cable has a limit to how much it can twist or rotate without being damaged
Solution Approach 1:
The patent incorporates a rotational overtravel protection device that preemptively prevents the cable from rotating beyond its safe limit. The device includes limit switches and triggering mechanisms that arrest rotation before the cable reaches its damage threshold, thus protecting the cable while allowing maximum safe rotation for energy transmission.
Solution Approach 2:
The rotational overtravel protection device acts as an intermediary between the rotating components and the cable. It monitors and controls the rotation, allowing the cable to twist within safe limits while preventing excessive rotation that would cause damage, thus mediating between the need for rotation and cable durability.
3Reliability
If the rotation of parts is limited to prevent cable damage, then cable durability is improved, but the moving parts cannot rotate sufficiently to meet application needs
Solution Approach 1:
The patent employs a dynamic rotational limit system where the protection device allows rotation up to a predetermined safe limit and then arrests further rotation. This dynamic approach enables the system to adapt - allowing maximum rotation when needed while automatically preventing damage when the limit is reached, thus balancing cable durability with application requirements.
4Reliability
If rotational limit switches are added to prevent overrotation, then cable protection is improved, but device complexity increases
Solution Approach 1:
The rotational overtravel protection device is designed to be self-regulating, using the rotation itself to trigger the limit switches. The triggering device rotates with the shaft and automatically activates the limit switches when the predetermined angle is reached, eliminating the need for external control systems and reducing overall device complexity while maintaining cable protection.
Data Source
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AI summary
A rotational over travel protection device for preventing over rotation of at least one of a cable, or a component operable with the rotational over travel protection device is provided. The device includes a housing, a rotatable shaft connected to the housing that can rotate relative to the house, and a triggering device supported in the housing and rotatable with the rotatable shaft. The device also includes a first and second rotational limit switch disposed in the housing. The switches are operable to be activated by the triggering device to arrest rotation of the rotatable shaft upon relative rotation of the rotatable shaft and the housing either a first or second rotation direction, respectively, at least 180 degrees from a zero position.