Retractable Tie-Down with Rotation Brake for User-Controlled Strap Tension
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Solution Overview
Problem
Existing tie-down assemblies do not allow the strap to remain in pay-out mode without automatic retraction, making it inconvenient for load adjustment and securing, and require direct attachment to an anchor point.
Innovation Solution
A retractable tie-down with a rotation brake that allows user-controlled retraction and pay-out, featuring a lanyard for rearward securement and a strap for forward securement, enabling adjustable tension without direct anchoring, and switchable modes through handle operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the strap automatically retracts around the spool when released, then the tie-down functions as designed with automatic retraction, but the user cannot maintain the strap in pay-out position for load adjustment or configuration
Solution Approach 1:
The system dynamically switches between two operational modes: automatic retraction mode and manual pay-out mode. The rotation brake can be engaged or disengaged based on user needs, allowing the strap to either automatically retract or remain in pay-out position for adjustment, thus resolving the contradiction between automatic operation and user control flexibility
Solution Approach 2:
The rotation brake changes the friction parameter applied to the spool. When fully engaged, it allows free rotation for pay-out; when partially engaged, it provides controlled resistance for user-controlled retraction; when fully engaged, it prevents rotation to maintain position. This variable parameter control enables both automatic retraction and manual positioning capabilities
2Reliability
If the tie-down is directly attached to an anchor point, then the mounting is positive and secure, but the user loses flexibility in positioning and configuration
Solution Approach 1:
The tie-down system is segmented into a fixed mounting portion (providing secure attachment to the vehicle) and a movable strap portion (providing positioning flexibility). The rotation brake mechanism acts as an intermediate control element that allows the strap to be positioned independently while maintaining secure mounting at the anchor point
Solution Approach 2:
The rotation brake serves as an intermediary mechanism between the fixed anchor point and the movable strap. It mediates between the need for secure positive mounting and the need for positioning flexibility, allowing the strap to be held at arbitrary positions while maintaining reliable connection to the anchor point
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
Enables user-controlled strap retraction and pay-out, allowing for adjustable tension and secure load management without automatic retraction, providing flexibility and convenience in securing loads without direct anchoring.
Implementation Method 1
The rotation brake impedes rotation of a spool on which the strap is wrapped and unwrapped during retraction and pay-out of the strap
Implementation Method 2
A spool spring between the spool and the assembly frame biases the spool to rotate in retraction
Data Source
AI summary
The retractable tie-down provides an adjustable strap under control of a rotation brake during retraction and pay-out. The rotation brake impedes rotation of a spool on which the strap is wrapped and unwrapped during retraction and pay-out of the strap as the tie-down operates in one of either a pay-out mode or a retraction mode. Thus, the rate of retraction of the strap is user-controlled through the rotation brake. The tie-down is provided with a lanyard issuing from rearward from the tie-down and a strap issuing forward from the tie-down for securement without direct, or positive attachment of the tie down to an anchor point, such as a chassis of a vehicle or the like.