Caster Pin Cam Mechanism for Low-Force Brake and Direction Locking
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Solution Overview
Problem
Existing caster systems for patient support apparatuses in healthcare facilities face issues with excessive force requirements, noise, and complexity, leading to potential patient falls and increased costs due to heavy, complex designs with multiple braking and directional mechanisms.
Innovation Solution
A cam mechanism integrated into a standard caster pin that combines braking and directional locking functions, using minimal force and reducing noise by incorporating a triple cam system with interlocking lifting members and ratchets, allowing for easier actuation and production simplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard caster system with individual locking systems or centralized locking systems is used, then the caster can be locked or braked, but too big or too small locking and braking forces are developed causing harm to casters or insufficient locking and braking
Solution Approach 1:
The cam mechanism geometry is optimized to provide variable mechanical advantage throughout the actuation stroke, enabling the system to develop appropriate locking and braking forces under different operating conditions without damaging the caster components
Solution Approach 2:
The cam mechanism acts as an intermediary between the actuating force and the braking/locking mechanism, transforming the applied force into optimized locking and braking forces through its geometric design
2Adaptability or versatility
If big double wheels with motor actuation are added to direct the patient support apparatus, then the desired direction of travel can be achieved, but the patient support apparatus becomes heavier, more expensive and more complex for production
Solution Approach 1:
The caster is designed with multi-functionality, enabling it to perform both propulsion and directional control functions through its ability to rotate around both horizontal and vertical axes, eliminating the need for separate directional control mechanisms
Solution Approach 2:
The directional control function is merged with the existing caster structure by enabling rotation around vertical axis, combining what would traditionally be separate functions into a single integrated component
3Adaptability or versatility
If casters with horizontal and vertical rotation are equipped with independent locking mechanism to lock direction of travel, then the caster can be properly directed, but the structure of the caster is complicated and requires additional levers or control members
Solution Approach 1:
The locking mechanism is integrated into the existing cam mechanism structure, combining the directional locking function with the braking mechanism and eliminating the need for separate independent locking levers or control members
Solution Approach 2:
The cam mechanism is designed to perform multiple functions including braking, directional control, and directional locking, making the locking mechanism universal rather than independent
4Adaptability or versatility
If a lever or control member for locking direction of travel is integrated in the caster itself, then the locking function is built-in, but it becomes complex and financially demanding
Solution Approach 1:
The directional locking function is merged with the existing cam mechanism components, eliminating the need for separate integrated locking levers and reducing manufacturing complexity and cost
5Length of stationary object
If casters are equipped with braking mechanism and directional mechanism using standard pin, then the caster height is decreased, but the mechanism must be actuated with minimal force while reducing noise
Solution Approach 1:
The cam mechanism geometry is optimized to provide high mechanical advantage, enabling the braking and directional mechanisms to be actuated with minimal force while maintaining effective locking and braking capabilities
Solution Approach 2:
The cam mechanism serves as an intermediary that amplifies the actuating force through its geometric design, reducing the force required to operate the braking and directional 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
This solution decreases the overall height of the caster, reduces noise, and simplifies the actuation process, enabling safer and more efficient operation with minimal force, while allowing for electronic actuation and cost-effective production.
Implementation Method 1
a cam mechanism (6) which comprises a cam for position of actuating pedal (6a), a cam for direction of caster (6b) and a cam for braking the caster and of vertical brake of caster (6c)
Implementation Method 2
number of ratchets (ratchet-wheels) which engage springs, preferably four springs, wherein each locking lever has its own spring
Data Source
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AI summary
An actuating mechanism assembly comprising a pin (2), a carrying member (3) and a caster (4) whereby the inner part of the pin (2) comprises a cam mechanism (8) comprising a number of cams (8a, 8b, 6c), wherein at least one cam from the number of cams (6a, 6b, 6c) is in contact with at least one lifting member (8), wherein at least one lifting member (8) is in contact with at least one locking lever (9), wherein at least one locking lever (9) is in contact with at least one ratchet (10), wherein at least one lifting member (8) or locking lever (9) is limited by at least one spring (11).