Cable Actuator Locking Pin for Wheelchair Brakes
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Solution Overview
Problem
Existing wheelchair braking systems are difficult to access for both users and attendants due to their proximity to the tire, limiting ease of operation.
Innovation Solution
A cable actuator system with a housing, handle, and locking pin, where the handle is pivotally connected and moves between released and locked positions, engaging a cable that actuates a wheelchair system, such as a wheel lock or service brake, with a biased locking pin ensuring secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the actuator is located in close proximity to the tire to achieve compact design, then the device complexity is reduced, but the ease of operation deteriorates as it becomes difficult to access by users and attendants
Solution Approach 1:
The actuator system is divided into two separate components: the cable actuator mechanism is mounted on the wheelchair frame at an accessible location, while the braking function is applied at the wheel tire through a cable connection. This segmentation allows the actuator to be easily accessible while maintaining compact braking action at the wheel.
2Reliability
If the locking pin is biased toward engagement with the locking detent to ensure secure locking, then the reliability is improved, but the ease of operation deteriorates due to increased force required to release
Solution Approach 1:
The locking pin is designed with a spring bias that dynamically adjusts the locking force. The spring provides sufficient bias to ensure secure engagement during normal operation, while the over-center mechanism allows for easy release when the handle is moved to the released position, as the spring force reverses direction to assist release.
3Reliability
If the handle is designed to move between released and locked positions with a locking detent to ensure secure positioning, then the reliability is improved, but the device complexity increases due to additional locking components
Solution Approach 1:
The locking function is merged into the handle mechanism itself. The handle incorporates a locking pin with a spring bias and a locking detent that are integrated into the handle's pivot structure. This merging provides secure positioning without requiring separate locking components, thus maintaining simplicity while ensuring reliability.
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 cable actuator system provides easy access and reliable operation of the braking mechanism, allowing users and attendants to easily lock or release the wheelchair wheels, enhancing mobility and safety.
Implementation Method 1
The locking pin is biased toward engagement with the locking detent such that when the handle is pivoted to the locked position, the locking detent aligns with the locking pin and causing the second end to engage the locking detent
Data Source
AI summary
A cable actuator comprises a housing, a handle, and a locking pin. The handle is pivotally connected to the housing and is moveable between a released position and a locked position. The handle has a slot that terminates in a locking detent. The locking pin has a first end configured to pass through the slot and a second end configured to engage the locking detent. The locking pin is biased toward engagement with the locking detent such that when the lever is pivoted to the locked position, the locking detent aligns with the locking pin permitting the second end to engage the locking detent.