Magnetic Locking Web Retract Mechanism
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Solution Overview
Problem
Existing locking web retractors lack a reliable and controllable mechanism to prevent web payout, especially under varying operating conditions, which can lead to unintended web release.
Innovation Solution
A locking web retractor with a ferromagnetic component and a magnetically or electromagnetically controlled locking mechanism that allows for selective prevention of spool rotation in the web payout direction, utilizing a mechanical or electrical switch to actuate the locking components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism is added to prevent web payout, then web release control is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical locking mechanisms with a magnetic field-based locking system. A magnet positioned near the spool creates a magnetic field that interacts with ferromagnetic material on the spool flange, providing reliable web payout prevention through non-contact magnetic forces rather than mechanical engagement components.
Solution Approach 2:
The patent controls the locking state by changing the position parameter of the magnet relative to the spool. By moving the magnet between a first position (where magnetic field strength is sufficient for locking) and a second position (where magnetic field strength is insufficient for locking), the system achieves web payout control through simple positional parameter change rather than complex mechanical actuation.
2Ease of operation
If a magnet is used to control locking, then ease of operation is improved, but manufacturing precision requirements worsen
Solution Approach 1:
The patent introduces a ferromagnetic component on the spool flange as an intermediary between the magnet and the spool rotation control. This ferromagnetic material concentrates and directs the magnetic field lines, creating a reliable locking effect that is less sensitive to variations in magnet positioning, thereby reducing manufacturing precision requirements while maintaining ease of operation.
Solution Approach 2:
The ferromagnetic material is pre-applied to the spool flange during manufacturing, creating a prepared magnetic interaction surface. This preliminary action ensures that when the magnet is positioned, the magnetic field immediately engages with the ferromagnetic material to provide locking, reducing the need for high-precision magnet positioning while maintaining reliable operation.
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 precise control over web payout and take-up, ensuring the spool remains locked under emergency or non-emergency conditions, enhancing safety and reliability by preventing unintended web release in harsh environments.
Implementation Method 1
a magnet positioned near the spool and responsive to actuation to produce a magnetic field to move the ferromagnetic component from the unlocking position to the locking position
Implementation Method 2
a permanent magnet positioned near the spool and movable between first and second positions relative to the ferromagnetic component, wherein in the first position a magnetic field produced by the permanent magnet does not cause the ferromagnetic component to move from the unlocking position to the locking position
Implementation Method 3
an electromagnet positioned near the spool and responsive to electrical power supplied thereto to produce a magnetic field to move the ferromagnetic component from the unlocking position to the locking position
Data Source
AI summary
A locking web retractor includes a frame including spaced-apart side walls, a spool rotatably mounted between the side walls, the spool rotatable in a web take-up pay out directions, locking components operatively coupled to the spool, a ferromagnetic component movable relative to the locking components between an unlocking position in which the ferromagnetic component does not cause the locking components to prevent the spool from rotating in the web pay out direction and a locking position in which the ferromagnetic component causes the locking components to prevent the spool from rotating in the web pay out direction, a magnet responsive to actuation to cause the ferromagnetic component to move from the unlocking position to the locking position to cause the locking components to prevent the spool from rotating in the web pay out direction, and means for actuating the magnet.