Webbing Winding Device Lock Mechanism Assembly
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Solution Overview
Problem
The existing webbing winding devices face challenges in assembly due to the bias force of compression coil springs, which complicates the interaction between components and affects the manufacturability of the second lock mechanism, and they struggle to change the magnitude of the force limiter load effectively.
Innovation Solution
A webbing winding device with a cylindrical spool and energy absorption sections that include a first and second lock unit, where the second lock unit is designed without a biasing spring, allowing for easier assembly and adjustable energy absorption by controlling the relative rotation between the guide unit and the spool, using a spring tab and ratchet teeth configuration to restrict rotation and engage the lock member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compression coil spring is used to provide bias force in the second lock mechanism, then the lock mechanism can function properly, but the assembly process becomes difficult due to the bias force resisting component assembly
Solution Approach 1:
The invention removes the compression coil spring from the second lock mechanism entirely. Instead of using spring bias force to engage the lock, the design uses a wire that interacts with a rotation circular plate to directly drive the locking action, eliminating the assembly difficulty caused by spring resistance while maintaining the locking function.
Solution Approach 2:
The invention introduces a wire as an intermediary element that transfers force from the rotation circular plate to the second lock pawl. This wire-mediated force transmission replaces the spring-based bias force system, allowing the lock mechanism to function without requiring assembly against spring resistance.
2Reliability
If the second lock mechanism is designed with spring bias force, then the lock can engage reliably, but the force limiter load magnitude cannot be effectively adjusted
Solution Approach 1:
The invention creates a dynamic force limiter system where the wire's interaction with the rotation circular plate allows the second lock pawl to engage at specific rotational positions. By controlling when and how the wire releases from the rotation circular plate, the system can dynamically adjust the force limiter load magnitude while maintaining reliable lock engagement through the pawl-ratchet teeth meshing.
3Reliability
If the wire interacts with the rotation circular plate to actuate the second lock mechanism, then the lock can be engaged, but the assembly becomes complex due to the interaction requirements
Solution Approach 1:
The invention merges the wire and rotation circular plate into an integrated force transmission system where the wire's path and the plate's rotation are designed to work together seamlessly. This unified design reduces assembly complexity by eliminating the need for separate spring mechanisms and their associated mounting requirements, while maintaining reliable lock actuation through the combined wire-plate-pawl interaction.
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 device achieves improved assembly characteristics and adjustable energy absorption by eliminating the need for biasing springs, simplifying the assembly process and allowing for selective energy absorption based on the occupant's load, enhancing the reliability of the webbing belt's restraining force.
Implementation Method 1
a spring tab extending from the plate portion, the spring tab engaging with the ratchet teeth due to an inherent resilience of the spring tab
Implementation Method 2
the first energy absorption section absorbing energy on a side further towards a first axial direction end of the spool than the spool-side coupling portion deforming plastically with respect to the spool-side coupling portion
Data Source
AI summary
It is provided a webbing winding device with good assembly characteristics of components in a second lock unit. In the webbing winding device, due to a leading end of a spring tab of a guide plate interacting with ratchet teeth of an internal ratchet and a second lock base rotating in the pull-out direction in this state, relative rotation occurs between the guide plate and the second lock base, and a second lock pawl is meshed with the ratchet teeth of the internal ratchet. Since this configuration is not a configuration in which relative rotation between the guide plate and a second lock base is induced by bias force of bias means, such as a compression coil spring or the like, there is no bias force received in the rotational circumferential direction when the guide plate and the second lock base are being assembled, resulting in easy assembly.