Electromagnetic Belt Retractor Locking Lever for False-Lock Prevention
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Solution Overview
Problem
Conventional mechanical locking devices in belt retractors require precise alignment of inertial masses with respect to vehicle axes, leading to unintentional locking issues, especially in vehicles with adjustable backrests, and are mechanically complex. Electrically actuatable locking devices address this but can be improved for enhanced locking movement and force conditions.
Innovation Solution
Incorporating an elastically deformable hook on the locking lever for damping, a second magnetic circuit to enhance holding force without increasing component size or load, and a pivotable locking lever with an elastic, bent tip to facilitate smooth movement and prevent pseudo-locking, along with cost-effective manufacturing via caulking and integrally molded components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inertial mass is used in a mechanical locking device to detect vehicle deceleration, then the locking function can be activated during accidents, but the device becomes mechanically complex and prone to unintentional locking due to misalignment issues
Solution Approach 1:
The patent replaces the mechanical inertial mass detection system with an electrical sensor system. The sensor detects vehicle deceleration and sends signals to a control device, which then actuates the locking mechanism electrically. This substitution eliminates the need for precisely aligned inertial masses and complex mechanical linkages, reducing mechanical complexity while maintaining or improving reliability through electronic control.
Solution Approach 2:
The patent introduces a control device as an intermediary between the sensor detection and the locking mechanism actuation. The control device processes sensor signals and determines when locking should occur, separating the detection function from the actuation function. This intermediary layer simplifies the overall system by allowing independent optimization of sensing and locking components.
2Ease of operation
If the belt retractor is designed with individualized contact surface orientation to prevent unintentional locking, then false locking is avoided, but the manufacturing and installation process becomes more complex
Solution Approach 1:
The patent replaces the mechanically oriented contact surface system with an electrical sensing system that detects vehicle deceleration regardless of installation orientation. The sensor and control device work together to distinguish between normal vehicle motion and accident conditions, eliminating the need for individually oriented mechanical components. This allows standardized manufacturing while maintaining the ability to prevent unintentional locking.
3Ease of operation
If additional disconnection mechanisms are added to prevent unintentional locking in adjustable backrests, then false locking is prevented, but the device complexity increases
Solution Approach 1:
The patent replaces mechanical disconnection mechanisms with an electrical control system. The sensor and control device monitor vehicle deceleration and selectively activate the locking mechanism only when accident conditions are detected. This electrical approach eliminates complex mechanical disconnection components while maintaining the ability to allow backrest adjustment during normal use and provide locking during accidents.
4Speed
If the locking lever movement is made faster when the electromagnet is deactivated, then the locking response time is improved, but the force conditions and movement efficiency need enhancement
Solution Approach 1:
The patent employs a spring-loaded locking lever that can dynamically change its movement characteristics. The spring provides a pre-loaded force that enables rapid lever movement when the electromagnet is deactivated. The system transitions from a static electromagnetic holding state to a dynamic spring-driven release state, achieving fast response time while maintaining controlled force conditions through the spring's elastic properties.
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 solution enhances the locking force and movement efficiency of the belt retractor, allowing for reliable restraint in both normal and emergency conditions without increasing component size or complexity, while enabling faster lever movement when the electromagnet is deactivated.
Implementation Method 1
a spring 4, which is held at one end on the housing 1 and is connected at the other end to an end of the locking lever 2 projecting outward from the upright first limb 16. The spring 4 is designed as a tension spring such that it biases the locking lever 2 into a position in which it engages in external teeth of a control disk 21
Implementation Method 2
an electromagnet 3 and a spring 4... The locking lever 2 comprises a contour part 24 and a steel plate 5, wherein the steel plate 5 faces the electromagnet 3 so that the locking lever 2 is attracted by the electromagnet 3 when the latter is energized
Data Source
AI summary
A belt retractor having an electrically actuatable locking device comprising a housing with a base plate and an upright first limb, a locking lever mounted pivotably on the upright first limb with a steel plate which is spring-loaded, and an electromagnet arranged in the housing and having a coil with a through opening, a first iron core which is arranged in the through opening, when a voltage is applied to the coil, exerts a magnetic force on the locking lever via the steel plate and actuates the locking lever for triggering a locking or unlocking movement against the force of the spring. The movement of the locking lever is enforced by a first magnetic circuit formed by the first iron core, the upright first limb and the portions of the base plate and of the locking lever between the first iron core and the upright first limb.