Roller Door Clutch Cam Assembly Without Leaf Spring Wear
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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 uneven load distribution, especially when technicians overestimate door travel parameters, leading to buckling or breakage. Additionally, these assemblies occupy more space than desired in modern door operator units.
Innovation Solution
A clutch assembly that eliminates the need for leaf springs by using a clutch base and cam configured for operative rotation in only one direction, distributing loads over a larger area and incorporating a torsion spring for pre-loading, allowing for compact and reliable engagement and disengagement of the motor drive, enabling manual operation during power failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a leaf spring is used to act as a ratchet pawl in the clutch assembly, then the disengage and reengage action can be achieved, but the leaf spring is prone to wear and tear and can eventually break under normal use
Solution Approach 1:
The invention extracts and eliminates the leaf spring component from the clutch assembly. Instead of using a leaf spring as a ratchet pawl, the patent employs a cam mechanism with a cam follower that interacts with the clutch lever to achieve the same disengage and reengage functionality without the wear-prone leaf spring.
Solution Approach 2:
The invention replaces the mechanical leaf spring ratchet system with a cam-based mechanical system. The cam profile is designed to interact with the clutch lever through a cam follower, providing the necessary engagement and disengagement actions through the cam's rotational movement rather than leaf spring flexing.
2Productivity
If the door travel parameters are overestimated during installation, then the door can close fully, but the bottom of the door hits the ground causing force to pass through the drive train to the leaf spring, causing the leaf spring to buckle or fail
Solution Approach 1:
The invention removes the leaf spring from the load-bearing path. The cam mechanism and clutch base are designed to absorb and distribute the forces generated during door operation, eliminating the leaf spring's role in transmitting door weight and impact forces to the drive train.
Solution Approach 2:
The cam profile and clutch base structure are designed to preemptively absorb and distribute impact forces before they can concentrate on a single component. The distributed load path through the clutch base prevents the buckling and failure that occurs when forces are concentrated on a leaf spring.
3Ease of operation
If a traditional clutch assembly with leaf spring is used, then the disengage function can be provided, but the assembly occupies more space than desired in modern slimmer profile door operator units
Solution Approach 1:
The invention transitions from a linear/planar leaf spring arrangement to a rotational cam mechanism. The cam rotates around an axis perpendicular to the direction of the clutch lever movement, utilizing a different spatial dimension to achieve the same functional result in a more compact footprint.
Solution Approach 2:
The invention combines multiple functions into the cam component itself. The cam profile simultaneously provides the disengage action, the reengage action, and the load distribution function that were previously separated across multiple components including the leaf spring, clutch lever, and associated mounting structures.
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 low-profile, durable clutch assembly that ensures reliable engagement and disengagement of the motor drive, reducing wear and tear, and accommodating a slimmer profile within door operator units, enhancing safety and operational reliability.
Implementation Method 1
a clutch base and cam configured for operative rotation in only one direction
Implementation Method 2
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.