Stamped Sheet Metal Bracket for Seat Belt Retractor Assembly

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Solution Overview

Problem

The assembly of seat belt retractors in electric or hybrid vehicles with raised floors is challenging due to limited space, making conventional screwing operations difficult or impossible with standard tools.

Innovation Solution

A stamped sheet metal support for the seat belt retractor with specific geometric features, including offset assembly planes and a three-dimensional stamping for stiffness, allows for reliable assembly and facilitates cable positioning and interior trim fixing, enabling easier assembly and mounting on the vehicle's raised floor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the floor is raised to accommodate accumulator batteries, then the volume for batteries is sufficient, but the space for retractor assembly is reduced

Engineering Contradiction:
Improvebattery volumeVSAvoidretractor assembly space
Core Design Contradiction:
Volume of moving objectVSArea of stationary object

Solution Approach 1:

The support structure utilizes a three-dimensional configuration with offset assembly planes at different heights and orientations. The first assembly plane is positioned for welding to the raised floor, while the second assembly plane is offset to provide access for screwing operations from inside the vehicle, effectively using vertical dimension to resolve the space constraint.

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

2Reliability

If the floor is raised, then battery autonomy is ensured, but conventional screwing operations become difficult or impossible

Engineering Contradiction:
Improvebattery autonomyVSAvoidscrewing operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The support structure is divided into distinct assembly planes: a first plane for welding operations to the raised floor, and a second offset plane for screwing operations. This segmentation allows each assembly operation to be performed on a plane optimized for its specific tool access requirements, resolving the conflict between raised floor reliability and assembly ease.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By creating an offset second assembly plane at a different height and orientation relative to the first plane, the design enables screwing operations to be performed from inside the vehicle without interference from the raised floor, adding a dimensional solution to the operational accessibility problem.

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

3Ease of operation

If a stamped sheet metal support with offset assembly planes is used, then assembly is facilitated, but the support geometry must be complex

Engineering Contradiction:
Improveassembly easeVSAvoidsupport geometry
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The support structure utilizes parameter changes in the stamping process to create offset assembly planes with specific spatial relationships. By controlling the offset distance, angles, and dimensions during stamping, the complex geometry is achieved through process parameters rather than assembly of multiple parts, balancing geometric complexity with manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2678194B1Bracket for safety belt winder
Publication Date: 2016.01.20 RENAULT SA
  • EP2678194B1 patent drawingFigure 1
  • EP2678194B1 patent drawingFigure 2~3
  • EP2678194B1 patent drawingFigure 4

AI summary

A bracket (4) made of pressed sheet metal for a motor vehicle safety belt winder comprises: - a first assembly plane (1) which is notched at a first sheet metal edge (11) by a profile (5) for keeping a winder in rotation, and comprises an orifice (16) through which a screw for securing a winder can be passed, - a second assembly plane (2) approximately parallel to the first assembly plane (1), offset with respect to the first assembly plane (1), and comprising a hole (9) able to receive a screw, the first assembly plane (1) and the second assembly plane (2) being connected by a first three-dimensional pressing (7) for stiffening the bracket (4) flexurally in at least two directions (x, y), - a third assembly plane (3) forming a zero angle or an angle of less than 20° with the first assembly plane (1), the third assembly plane (3) bordering the first assembly plane (1) one a side of this assembly plane opposite the first sheet metal edge (11), the third assembly plane (3) having a free edge on its side opposite the first sheet metal edge (11).