Seat Belt Reed Sensor Sensor REED RELAYS REED SENSORS REED SWITCHES Introduction As we all know, seat belts are now used by all airlines and in almost all automotive vehicles with the possibility that they may become mandatory for buses and trains as well. In recent years the Reed Switch sensor has been discovered by safety belt designers as being perhaps the best and most reliable way to detect when a seat belt has been engaged. Figure 1. A) Picture of Reed Switch Sensor & (B) Actuator Magnet Housing Features • Hermetically sealed • Designed for SPST (Form A) and SPDT (Form C) switching • Dynamically tested contacts • Reliable switching • Ability to activate and control switching function from only one side of the buckle Figure 2. Shows the entire seat belt in the buckled position. Reed Switch is actuated. So when the tongue section of the buckle is inserted and connected to the main buckle housing the sensor and magnet become magnetically isolated. This in turn carries out the switching/sensing function. • Designed to handle high shock environments • Designed to operate in dirty environments • Millions of reliable switching operations Applications • Detection is seat belt closure in aircraft seat belt detection where ever used Figure 3. Shows the entire seat belt in the unbuckled position. MEDER Has Has Developed Both A Normally Open Open (Form A) Solution And And A Single Pole Double Throw (Form C) Solution Everyone has experienced the need to fasten their seat belts; and because of the safety aspect, laws have been passed making it mandatory to ‘buckle up’. Identifying a reliable technology that could be used to indicate the closure and opening of a seat belt aboard an aircraft has been a difficult challenge until Reed Sensors were considered. Aboard an aircraft, several times a day, different passengers will make the aircraft seat their residence. Some of these people are careful and conscience and some are not as careful, The net result to the seat belt is that it can be slammed around, spilled upon, splattered with MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 1 of 2 www.meder.com Seat Belt Reed Sensor Sensor REED RELAYS REED SENSORS REED SWITCHES food, used as toys by children, etc. etc. The hermetically sealed Reed Switch is perfectly suited to withstand the above abuses and still perform its switching function. Specifications (@ 20° 20°C) KSS Series Operate specs Min Max Units Must close distance Ref Ref mm Must open distance Ref Ref mm Hysteresis Load Characteristics Switching voltage Switching current Carry current Contact rating Static Contact resistance Dynamic contact resistance Breakdown voltage Operate time Release time Operate Temp Storage Temp Min Max Units 150 1.0 1.0 10 150 250 200 2.5 1.5 -20 130 -55 100 V Amps Amps Watts mΩ mΩ V msec msec °C °C MEDER is currently working closely with the airline industry to develop a Reed Sensor that will be electrically connected to a panel to indicate when and where an unbuckled seat belt for a given seat exists. Flight attendants and/or the pilot will quickly be able to make this observation and correct the condition accordingly. MEDER has developed a sensor totally built into the receiving buckle (see picture sequence). The receiving buckle is the larger of the two that receives the metal ‘tongue’ from the other buckle element. MEDER has come up with an approach whereby the metal ‘tongue’, when inserted into the other seat belt element, blocks the magnetic system in place between a magnet and Reed Sensor. This interference essentially isolates the two elements from each other, changing the state of the Reed Sensor contacts. When the seat belts are disengaged, the interference no longer exists and the Reed Sensor contact reverts to the reset state. This Reed Sensor design also needed to take into consideration all the magnetic elements internal and external to the seat belt. The Reed Sensor’s reliability is unquestioned, where tens of millions of operations are typical. Cylindrical Panel Mount Series Series MK03 MK03 Dimensions mm Dia 5.25 L 25.5 Illustration inches 0.207 1.004 MK14 MK14 Dia L 4 25.5 0.157 1.004 MK18 MK18 Dia L 5 17 0.197 0.669 MK20/1 MK20/1 Dia L 2.72 10 0.107 0.394 Rectangular Screw Flange Mount Series Series MK04 MK05 MK05 MK12 MK12 Dimensions mm W 13.9 H 5.9 L 23.0 W 19.6 H 6.1 L 23.2 W H L 14.9 6.9 32.0 Illustration inches 0.547 0.232 0.906 0.772 0.240 0.913 0.587 0.272 1.260 **Consult the factory for more options not listed above. ** MEDER electronic Application MEDER electronic AG | Germany | tel.: +49(0)7731/8399-0 | Email: [email protected] MEDER electronic Inc. | USA | tel.: +1 508.295.0771 | Email: [email protected] Page 2 of 2 www.meder.com