Roller Door Clutch Cam Assembly for Slim Overload-Tolerant Operators
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Solution Overview
Problem
Existing clutch assemblies for roller door operators, which rely on leaf springs for disengage and reengage actions, are prone to wear and tear, and can fail due to overloading, especially when technicians overestimate door travel parameters, leading to buckling or breakage, and require a more compact design to fit within slim profiles.
Innovation Solution
A clutch assembly that eliminates the need for leaf springs by using a clutch base and cam configured for operative rotation in one direction, distributing load over a larger area, and incorporating a torsion spring for pre-loading, allowing for selective engagement and disengagement with a single pull of a clutch string, while maintaining a compact profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a leaf spring is used to act as a ratchet pawl for disengage and reengage actions, then the clutch assembly can provide selective engagement, but the leaf spring is prone to wear and tear and can eventually break
Solution Approach 1:
The patent removes the leaf spring component entirely from the clutch assembly. Instead of using a leaf spring as a ratchet pawl, the invention employs a cam mechanism with a cam follower that provides the disengage and reengage actions through rotational movement, eliminating the wear and tear problems associated with leaf springs.
Solution Approach 2:
The patent replaces the mechanical leaf spring ratchet system with a cam-based mechanical system. The cam rotates on its axis and uses its profile to control the engagement and disengagement of the clutch plates, substituting the flexible leaf spring mechanism with a rigid cam profile mechanism that is more durable.
2Strength
If the clutch assembly is designed with sufficient load-bearing capacity, then it can handle overloading conditions, but the profile becomes larger and cannot fit within slim operator units
Solution Approach 1:
The patent transitions from a linear load-bearing approach to a rotational dimension. The cam rotates on its axis, allowing the load-bearing surfaces to be distributed around the circumference of the cam rather than requiring a long linear structure. This enables the clutch assembly to handle overloading conditions while maintaining a compact profile suitable for slim operator units.
Solution Approach 2:
The patent employs a dynamic cam mechanism where the cam profile is designed to distribute loads over a larger area during rotation. The cam follower tracks the cam profile, allowing the load to be distributed across multiple contact points during the rotation cycle, providing enhanced load-bearing capacity within a compact space.
3Reliability
If the clutch assembly allows manual operation during power failures, then safety and reliability are improved, but the mechanism becomes more complex
Solution Approach 1:
The patent designs the cam mechanism to serve multiple functions: it provides both the engagement and disengagement actions, and it enables both motor-driven operation and manual operation. The same cam and cam follower arrangement handles normal motor-driven engagement and also allows manual disengagement during power failures, eliminating the need for separate mechanisms for different operating modes.
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 a more durable and compact clutch assembly that reduces wear and tear, allows for safer assembly, and ensures reliable operation by distributing loads effectively, enabling manual operation during power failures and maintaining motor-driven control.
Implementation Method 1
incorporating a torsion spring for pre-loading
Data Source
AI summary
A clutch assembly for a roller door operator, the clutch assembly providing selective engagement with a drive wheel, the clutch assembly comprising: a rotatable shaft rotatable relative to the drive wheel; a clutch disc supported in a clutch lever and arranged to rotate with the rotatable shaft, the clutch disc and clutch lever configured to rotate relative to one another around the axis of rotation of the shaft; and a clutch cam supported in a clutch base, the clutch base configured to permit operative rotation of the clutch cam around the axis of rotation of the shaft in a first direction; wherein the clutch lever is operatively associated with the clutch cam so that rotational movement of the clutch lever in a second direction opposite to the first direction actuates movement of the clutch disc and the clutch lever axially along the rotatable shaft to engage or disengage the clutch disc with the drive wheel, and subsequent rotational movement of the clutch lever in the first direction actuates rotational movement of the clutch cam relative to the clutch base in the first direction.