Device for the measurement of position in vehicle restraint systems

Patent Description

A new device integrated into the restraint system that allows measuring displacement and knowing the position of a vehicle's seat belt at all times has been developed and patented. Companies interested in commercially exploiting the product or interested in establishing R&D collaboration agreements are sought.

The Challenge

The seat belt is a key element of vehicle restraint systems. Currently, linear sensors are used to measure the longitudinal displacement of the seat belt webbing from a certain position, but they have several limitations. Their large dimensions prevent their use in certain small or convertible vehicles. Additionally, a millimetered and calibrated plastic tape attached to the belt strap is needed, implying a change in the diameter of the seat belt reel, with the risk of interrupting the correct operation of the mechanical belt assembly and giving a false reading.

The Technology

The technology presented here allows measuring the displacement and knowing the position of the seat belt at all times, solving many of the drawbacks of current meters. The device can be used for data extraction or to activate signals that trigger vehicle safety elements such as seat belt pretensioners or the airbag. This reduces the risk of injuries due to the passenger's position. The system is based on the integral incorporation of an encoder, incremental or absolute, into the reel of any seat belt, allowing obtaining the position and speed as well as the direction of rotation of the retractor reel. An encoder is an electric-optical-mechanical sensor that provides information on linear or angular position and transforms translational or rotational movement into a series of digital pulses. The device is complemented by an electronic control system that captures, adapts, and processes the signal so that it can be interpreted by the vehicle's electronic measurement systems, both analog and digital.

Innovative Advantages

• Measurement based on the angular position of the pulleys, performed without contact with the belt, avoiding braking errors due to its slippage with the sensor element.
• Improves occupant protection by allowing continuous monitoring of the seat belt position at all times.
• Depending on the application, it can incorporate sensors of higher or lower precision.
• Viable and compatible in any vehicle and with any seat belt.

Current Development Status

The prototype has been tested and validated in collaboration with the Passive Safety Laboratory of the company Applus+ IDIADA, where static and dynamic tests have been carried out with a sled using generic measuring instrumentation.

Target Market and Applications

• Companies in the automotive sector dedicated to manufacturing restraint systems that are interested in incorporating a new product capable of measuring displacement and knowing the position of the seat belt at all times.
• Passive Safety Laboratories, as it represents a displacement measurement system for seat belts that solves the drawbacks of current measurement systems.