Webbing Take-Up Device Inversion for Assembly Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing webbing take-up devices face difficulties in assembly and operation due to the hidden inner end of the main power spring, which makes it challenging to offset the biasing force effectively, leading to increased tension on the webbing belt when worn by an occupant.
Innovation Solution
A webbing take-up device design that includes a spool with a biasing member generating a take-up force, an offset biasing member resisting this force, and a rotation transmission member to offset the biasing force, allowing for easier assembly and reduced tension on the webbing belt by arranging components in a way that the offset biasing member is easily recognizable and connectable, thereby reducing the assembly complexity and tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner end of the main power spring is locked to the winding shaft that has passed through the ratchet wheel, then the tension reducer can function to offset the biasing force, but the inner end of the main power spring becomes hidden by the ratchet wheel or case member, making it difficult to operate and assemble
Solution Approach 1:
The patent inverts the conventional arrangement by having the ratchet wheel pass through the main power spring rather than the spring passing through the ratchet wheel. This inversion makes the inner end of the main power spring accessible from the opening side of the case, enabling easy assembly and operation while maintaining the tension reducer function. The rotation transmission member is locked to the inner end of the main power spring, allowing rotational force transmission in the take-up direction.
2Productivity
If the components are arranged to make the offset biasing member easily recognizable and connectable, then assembly efficiency improves, but the structural complexity increases
Solution Approach 1:
The patent introduces a rotation transmission member as an intermediary component that connects the spool biasing member to the offset biasing member. This intermediary element facilitates the transmission of rotational force from the spool biasing member to the other end of the offset biasing member, enabling efficient assembly while maintaining clear functional relationships between components. The rotation transmission member acts as a mediator that simplifies the assembly process despite the multi-component structure.
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 design enhances assembly efficiency and reduces the force required to pull the webbing belt into the spool, decreasing the static fastening force on the occupant and maintaining a lower dynamic fastening force during movement, improving user comfort and operational ease.
Implementation Method 1
a spool biasing member provided inside the case and connected directly or indirectly to the spool so as to generate a take-up biasing force to the spool in a take-up direction opposite to the pull-out direction
Implementation Method 2
an offset biasing member arranged within the case on the opposite side of the spool biasing member from the spool, one end of the offset biasing member engaging with the rotating body so as to be rotatable along with the rotating body, and the offset biasing member producing an offset biasing force which resists the take-up biasing force
Implementation Method 3
the other end of the offset biasing member locked to the rotation transmission member such that the rotation in the take-up direction can be transmitted to the other end of the offset biasing member
Data Source
AI summary
A webbing take-up device which can improve the workability of the assembly work of a tension reducer is obtained. In this webbing take-up device, a take-up spring unit is arranged closer to the opening side of a case than a reduction spring unit within a case. For this reason, when a clutch is arranged inside the reduction balance spring and the inner end of the reduction balance spring in a spiral direction is locked to a spring case of the clutch, the clutch and the reduction balance spring can be easily and visually recognized from the opening side of the case. Thus, the other end of the reduction balance spring can be easily locked to the spring case.