Belt Retractor Coupling Pawl Blocking Contour
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing belt retractors face issues with undesired engagement of coupling pawls with the belt reel's toothing due to extreme vibrations, which can interfere with the operation of reversible and irreversible belt tensioners, leading to potential disturbances in the normal use and activation of the seat belt device.
Innovation Solution
The introduction of a blocking contour on the friction ring and/or coupling pawl that prevents unintended engagement by blocking the coupling pawl in a defined parking position, requiring deliberate activation to release the blocking mechanism and allow coupling with the belt reel, thus ensuring controlled and safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the coupling pawl is designed to freely engage with the belt reel's toothing for normal operation, then the ease of operation is improved, but the reliability deteriorates due to undesired engagement during extreme vibrations
Solution Approach 1:
The coupling pawl is pre-positioned in a parking position by a blocking contour before operation is needed. This preliminary positioning prevents undesired engagement during vibrations while maintaining the capability for deliberate engagement when activation is required
Solution Approach 2:
The blocking contour acts as an intermediary element between the coupling pawl and the toothing. It provides a intermediate parking position that prevents direct engagement with the toothing, thereby eliminating undesired coupling while allowing controlled engagement through deliberate activation
2Reliability
If a blocking mechanism is introduced to prevent undesired engagement, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The blocking contour is merged with the friction ring structure, integrating the blocking function into an existing component rather than adding a separate blocking device. This reduces overall device complexity while maintaining reliability
Solution Approach 2:
The friction ring serves multiple functions: it provides frictional engagement for belt tensioning and incorporates the blocking contour to prevent undesired coupling. This multi-functionality eliminates the need for dedicated blocking components, reducing device complexity
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
This solution effectively reduces the likelihood of undesired coupling during vibrations, ensuring the belt retractor operates correctly by maintaining the coupling pawl in a blocked position until deliberate activation, preventing interference with the belt reel's rotation and ensuring proper tensioning and restraint functionality.
Implementation Method 1
the friction ring and/or the coupling pawl has a blocking contour which is positioned in such a way that the coupling pawl abuts thereon after being disengaged from the toothing and is blocked in the direction of a repeated engagement movement into the toothing
Implementation Method 2
the coupling pawl abuts thereon after being disengaged from the toothing and is blocked in the direction of a repeated engagement movement into the toothing
Data Source
AI summary
A belt retractor for a motor vehicle seat belt device, with a rotatably mounted belt reel onto which a seat belt is wound, and a belt tensioner with a drive wheel (1), which drives the belt reel in the event of an activation. A positively controlled tensioner coupling transfers the drive movement from the drive wheel (1) onto the belt reel. At least one coupling pawl (2,3) mounted on the drive wheel (1) and which is moved into and out of engagement with a toothing (20) rotationally fixed in relation to the belt reel to establish and disconnect a rotational connection of the drive wheel (1) with the belt reel. A friction ring (4) has a control arm (11) coupled with the coupling pawl (2,3), wherein in the event of an activation of the belt tensioner, the friction ring (4) performs a relative movement to the drive wheel (1) by frictional forces and, controls via the control arm (11) the movement of the coupling pawl (2,3) into engagement and disengagement with the toothing (20). The friction ring (4) and/or the coupling pawl (2,3) has a blocking contour (12), positioned such that the coupling pawl (2,3) abuts thereon after the disengaging movement out of the toothing (20) and is blocked in the direction of a repeated engagement movement into the toothing (20).