Roller Shade Tensioner With Spring-Biased Slack Lock
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Solution Overview
Problem
Existing roller shades lack effective mechanisms to prevent slack in the actuator, posing safety hazards.
Innovation Solution
A tensioner mechanism with a lock arrangement that includes a plunger biased to move between extended and retracted positions, arresting actuator passage when slack occurs, featuring a resilient finger and a jaw to grip the actuator, ensuring smooth operation and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no lock arrangement is provided, then the device complexity is reduced, but safety hazards occur due to actuator slack
Solution Approach 1:
The plunger is designed to dynamically transition between retracted and extended positions based on actuator tension. When the actuator is taut, the plunger remains retracted allowing smooth operation. When slack occurs, the plunger automatically extends to engage the lock arrangement, providing dynamic safety response without constant mechanical intervention.
Solution Approach 2:
The spring-loaded plunger mechanism automatically detects and responds to actuator slack conditions without external control. The spring bias ensures the plunger self-activates when tension is lost, engaging the lock arrangement to prevent dangerous drooping, and self-resets when tension is restored, providing autonomous safety functionality.
2Reliability
If a lock arrangement is added to arrest actuator slack, then safety is improved, but the ease of operation deteriorates due to potential interference with actuator movement
Solution Approach 1:
The plunger's dynamic positioning ensures the locking surfaces are only engaged when needed. During normal operation with taut actuator, the plunger is retracted and does not interfere with actuator passage through the tensioner. The bearing surface remains accessible for smooth actuator movement, eliminating operational interference while maintaining safety readiness.
Solution Approach 2:
The plunger acts as an intermediary element between the actuator and the lock arrangement. It selectively mediates the interaction by remaining out of the way during normal operation and only engaging to arrest movement when slack is detected, thus protecting the actuator system without interfering with its primary function.
3Reliability
If the plunger is biased towards extended position for automatic locking, then safety response is improved, but the productivity deteriorates due to frequent engagement of lock arrangement
Solution Approach 1:
The spring provides a counteracting force (bias) that balances the plunger in the retracted position during normal operation. This spring force acts as a counterweight to the locking engagement, ensuring the plunger only extends when the actuator slack overcomes the spring bias, thus preventing frequent unnecessary engagements while maintaining rapid safety response capability when needed.
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 tensioner mechanism effectively arrests actuator slack, enhancing safety by maintaining tautness and preventing hazards, while allowing smooth operation.
Implementation Method 1
the tensioner can further comprise a spring that biases the plunger for movement towards the extended configuration
Implementation Method 2
the resilient finger springing into the socket when the plunger reaches the extended position
Data Source
AI summary
The tensioner is mounted in use to a vertical surface for throughpassage in taut relation of a clutch actuator selected from ball chain and cord and comprises a lock arrangement which: includes a plunger having a bearing surface; and, in use, is adapted to arrest throughpassage of the actuator in slack conditions. The plunger, in use, is: (i) adapted for vertical movement between an extended position and a retracted position that is elevated in relation to the extended position; adapted, when in the retracted position, to receive the actuator in the manner of a pulley, for smooth operation of the shade; and biased for movement towards the extended position. The lock arrangement is adapted, in use: upon movement of the plunger to the extended position, to arrest movement of the plunger towards the retracted position; and, when the plunger is in the extended position, to arrest throughpassage of the actuator.