Sensor Developments Inc. (SDI) has developed a new, high performance, "low mass" sensor to monitor forces in seat belts and other restraining harnesses. The sensor utilizes a proprietary "three bar" system, which minimizes errors caused by belt thickness effects. The low wrap angles utilized with this concept, create minimum webbing disturbance, reduce the forces in the sensor, and permit large reductions in sensor weight.

Low sensor weight (mass) is very important for crash testing applications where the sensor undergoes large deceleration forces. Existing sensor designs can create large errors due to these forces.

The sensor utilizes a strain gage bridge and has a nominal output of 2 mv/v at 3500 lbs.It is designed to fit on standard, 2" wide seat belts. Total sensor weight is less than 4 ounces, and even lower weight models are currently in the testing stage.

The sensor utilizes a lightweight molded "break-away" connector on a short pigtail extension. It is designed to allow this pigtail to be easily replaced if damaged during usage. The sensor can also be supplied with other cable and connector options as required. It can be installed on a seat belt without tools or belt "threading".

The design concept can be extended to other capacities and webbing sizes on special order. Price and delivery information is available by contacting SDI's Application Engineers at 1-(888)-SENSOR-1.

SDI is a designer and manufacturer of force and torque sensors, systems, and associated data acquisition equipment.