Seat Belt Safety Device with Release Unit for Post-Crash Unfastening
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Solution Overview
Problem
Conventional seat belt safety systems face difficulties in unfastening the seat belt from the buckle after the air bag deployment due to high tension, which hinders the occupant's ability to escape safely during a car collision.
Innovation Solution
A safety device for seat belts that includes a retractor with a rack gear, a pretensioner to wind the seat belt upon collision, a release unit operated by a switch unit to unwind the seat belt, and a safety latch mechanism, allowing for easy unfastening after the pretensioner has wound the seat belt to a predetermined length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pretensioner operates to tighten the seat belt upon collision, then the occupant positioning is improved, but the difficulty of unfastening the seat belt increases
Solution Approach 1:
The release unit is activated automatically after the pretensioner operates, performing the preliminary action of loosening the seat belt before the occupant needs to unfasten it. This resolves the contradiction by preparing the system in advance to counteract the high tension created by the pretensioner.
Solution Approach 2:
The release unit acts as an intermediary mechanism between the pretensioner and the seat belt buckle. It receives the trigger signal from the switch unit and mediates the tension release by rotating the rack gear in the unwinding direction, making unfastening easier after collision.
2Ease of operation
If the release unit is made operable immediately, then the ease of unfastening is improved, but the risk of misoperation increases
Solution Approach 1:
The switch unit is designed to detect the operation state of the pretensioner before enabling the release unit. This preliminary detection ensures that the release unit can only be activated after the pretensioner has completed its tightening function, preventing premature or misoperative release.
Solution Approach 2:
The switch unit provides feedback about the pretensioner's operation state to control the release unit's availability. This feedback mechanism ensures that the release unit is only operable when appropriate (after pretensioner activation), balancing ease of unfastening with misoperation prevention.
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 reduces shock from the air bag deployment, prevents misoperation of the release unit, and enables easy unfastening of the seat belt, enhancing occupant safety by allowing safe escape from the vehicle.
Implementation Method 1
a second connection part converting a pressing operation of the button member into electricity, and transferring the electricity to the release unit. The second connection part includes a piezoelectric ceramic receiving a pressure through the button member, and generating electricity
Implementation Method 2
a first explosion part exploded by an operation of an impact sensor, and moving the first support member in a direction facing the rack gear. The first support member is pushed by a pressure of a gas produced due to an operation of the first explosion part and is moved in the housing
Implementation Method 3
a second explosion part exploded by the electricity transferred from the switch unit, and moving the second support member in a direction facing the first support member. The second support member is pushed by a pressure of a gas produced due to an operation of the second explosion part and is moved in the housing
Data Source
AI summary
A safety device for a set belt includes a retractor having a rack gear on a circumferential outer surface of which the seat belt is wound; a pretensioner operated upon a collision of a car and rotating the rack gear in a direction for winding the seat belt; a release unit installed adjacent to the pretensioner, operated after the pretensioner operates the rack gear, and rotating the rack gear in a direction for unwinding the seat belt; and a switch unit receiving a manipulation force for operating the release unit, generating electricity, transferring the electricity to the release unit, and operating the release unit.