Caster Cam Mechanism for Low-Force Braking and Directional Locking
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Solution Overview
Problem
Existing caster systems for patient support apparatuses in hospitals and nursery facilities face issues with excessive force requirements for braking and directional control, leading to potential harm, insufficient locking, and increased noise levels.
Innovation Solution
An actuating mechanism for casters that integrates both braking and directional locking mechanisms into a standard pin, utilizing a cam mechanism with multiple switch mechanisms to minimize force exertion and optimize position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard caster system is used for patient support apparatuses, then the caster can rotate around horizontal and vertical axes to move the bed, but excessive force is required for braking and directional control
Solution Approach 1:
The patent combines the braking mechanism and directional locking mechanism into a single integrated cam mechanism located in the pin of the caster. This unified mechanism allows both braking and directional control to be actuated by a single pedal, reducing the force required compared to separate systems and resolving the contradiction between ease of operation and force requirements.
Solution Approach 2:
The cam mechanism in the pin serves multiple functions simultaneously: it controls braking, directional locking, and position indication. This multi-functionality eliminates the need for separate mechanisms for each function, reducing overall system complexity and the force required for actuation, thereby improving ease of operation while managing force requirements.
2Reliability
If individual locking systems are installed at each caster, then braking and directional control are achieved, but the structure becomes complex and space-consuming
Solution Approach 1:
The patent integrates multiple locking functions (braking and directional control) into a single cam mechanism within the pin, eliminating the need for separate locking systems at each caster. This consolidation maintains reliable locking capability while significantly reducing structural complexity and saving space within the caster assembly.
Solution Approach 2:
The cam mechanism is nested within the pin structure of the caster, with multiple functional components arranged concentrically or in compact layers. This nesting approach allows the complex multi-function mechanism to be housed within the existing pin space, maintaining reliability while minimizing structural complexity and space requirements.
3Productivity
If a centralized braking system is used, then all casters can be braked at once, but the system requires additional components increasing weight and cost
Solution Approach 1:
The cam mechanism in each caster pin provides multi-functionality, including braking capability. While each caster has its own mechanism, the design is so compact and integrated that it avoids the need for heavy centralized braking components, maintaining productivity through reliable braking while minimizing weight increase compared to traditional centralized systems.
4Strength
If metal components are used for durability, then strength is improved, but noise level increases
Solution Approach 1:
The patent employs composite material construction, combining metal components for structural strength with plastic components for noise reduction. Specifically, the cam mechanism and surrounding components utilize plastic materials that provide sufficient strength while significantly decreasing noise generation during operation, thus resolving the contradiction between strength and noise level.
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 simplifies the caster structure, reduces the total height of the caster, and decreases the noise level by allowing components to be made from plastic materials, while enabling effective braking and directional control with minimal force.
Implementation Method 1
a cam mechanism (6) with 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
A spring member (25) under yoke does not develop sufficient force to brake the brake drum
Implementation Method 3
the brake band (20) shrinks around the brake drum (18) which brakes the caster with two-way band brake (17)
Data Source
AI summary
An actuating mechanism for a caster that brakes and positions the caster by means of a cam mechanism that enables braking of the caster using minimum forces developed on the brake lever or brake rod. The mechanism helps to handle casters of patient support apparatuses in hospital and nursery facilities easily, using minimum force developed by caregivers or by an electronic caster brake systems if used for braking of casters of patient support apparatuses, as well. The mechanism may produce an outstanding decrease of noise level of castors on patient support apparatuses.