Electric Belt Retractor Locking with Damped Magnetic Lever

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Solution Overview

Problem

Conventional mechanical belt retractor blocking devices require precise alignment with vehicle axes, leading to complexity and unintended blocking issues, especially in vehicles with adjustable backrests, necessitating individual customization and additional compensating mechanisms to prevent accidental blocking.

Innovation Solution

An electrically actuatable blocking device with a damping element, such as an elastically deformable hook on the blocking lever, and a second magnetic circuit to enhance holding force without increasing component size or load, allowing for improved alignment flexibility and reduced complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanical blocking device with an inertial mass is used, then the blocking function is provided, but the device requires precise alignment with vehicle axes and becomes mechanically complex

Engineering Contradiction:
Improveblocking functionVSAvoidalignment requirements and compensating mechanisms
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical inertial mass-based blocking device with an electrically actuatable blocking device. The electromagnet controls the blocking lever's position, substituting the mechanical inertia-based operation with an electrical control system. This eliminates the need for precise alignment with vehicle axes and removes the requirement for complex compensating mechanisms for adjustable backrests.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electrically actuatable blocking device provides universal mounting capability across different vehicle types and installation positions. The electrical control system can be integrated with various vehicle systems (airbag control, driving dynamics assistance), making the blocking device adaptable to multiple functions and configurations without requiring mechanical reconfiguration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an electrically actuatable blocking device is used, then alignment flexibility is improved, but holding force may be insufficient

Engineering Contradiction:
Improvemounting position flexibilityVSAvoidholding force on blocking lever
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The patent introduces a second magnetic circuit in addition to the first magnetic circuit of the electromagnet. This second magnetic circuit, formed by a second iron core and corresponding magnetic path, acts in parallel with the first circuit to provide additional holding force on the blocking lever, thereby compensating for the reduced mechanical leverage from flexible mounting positions.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent combines two magnetic circuits (first and second) within the same electromagnet assembly to generate cumulative holding force. The magnetic fields from both circuits work together to securely hold the blocking lever in the blocked position, ensuring sufficient holding force even when the device is mounted in positions optimized for adaptability rather than mechanical advantage.

Inventive Principle:
Principle #5Merging (Combining)

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 the belt retractor to be mounted universally and prevents unintended blocking, ensuring occupant safety while allowing for easier adjustment and reduced mechanical complexity.

Implementation Method 1

an electromagnet 3, which can hold the blocking lever 2 in the blocked position independently of the installation position

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

The electrically actuatable blocking device 100 comprises as basic elements a housing 1 with an L-shaped basic structure with a base plate 15 and a first upstanding leg 16, a blocking lever 2 pivotably mounted on the first upstanding leg 16 of the housing 1, an electromagnet 3

Methodology Applied
Scientific EffectElectromagnetism: Electromagnet

Implementation Method 3

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 outwards from the first upstanding leg 16. The spring 4 is designed as a tension spring in such a way that it prestresses the blocking lever 2 into a position in which it engages in an external toothing of a control disk 21

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4028291B1Belt retractor having an electrically actuatable locking device
Publication Date: 2023.08.23 AUTOLIV DEV AB

AI summary

The present invention relates to a belt retractor having an electrically actuatable locking device (100) comprising a housing (1) with a base plate (15) and an upright first limb (16), a locking lever (2) mounted pivotably on the upright first limb (16) with a steel plate (5) which is spring-loaded by means of a spring (4), and an electromagnet (3) arranged in the housing (1) and having a coil (10) with a through opening (14), a first iron core (12) which is arranged in the through opening (14) and which, when a voltage is applied to the coil, (10) exerts a magnetic force on the locking lever (2) via the steel plate (5) and actuates said locking lever for triggering a locking or unlocking movement against the force of the spring (4). The movement of the locking lever (2) is enforced by a first magnetic circuit (I) which is formed by the first iron core (12), the upright first limb (16) and the portions of the base plate (15) and of the locking lever (2) between the first iron core (12) and the upright first limb (16), a damping element (13) being provided, which is arranged in such a way that it damps the movement of the locking lever (2) relative to the housing (1) in at least one portion of the movement curve of the locking lever (2), and the damping element (13) being formed by at least one elastically deformable hook arranged on the locking lever (2).