Platform Safety Sensors Today's article takes a look at both commercial and domestic platform safety sensors, explaining the types of sensors used and their differences. Hydraulic and electrically powered platforms are a feature of many commercial vehicles, and some domestic and leisure ones as well. Ambulances use a platform at the rear of the vehicle, to convey patients into and out of the ambulance without the paramedics having to lift a stretcher in, or cause undue stress to a critical patient. Some wheelchair accessible minivans also use a lift to make it possible for heavy wheelchairs to get in and out; people with a high dependency condition often use an electric wheelchair with batteries and complex controls, all of which add weight and bulk. Heavy goods vehicles use tail lifts to facilitate the loading and unloading of cargo; some even carry a small forklift on the back for loading exceptionally heavy or bulky items. Linear non-contact sensors are used to detect the position of the platforms at any given moment, and are also used to stop the platform from moving too far. The sensors are mounted to the vehicle and the platform and because they do not need to be in contact with each other to work, there is no risk of system failure due to contamination. This reliability is incredibly important for paramedics, who are occupied with patient care and need to be able to trust their equipment to perform correctly every time.The lift on the back of a double-layer trailer has more work to do than any of the examples above, because instead of only moving from ground level to the height of the vehicle loading floor, they need to also be able to go as high as the second layer flooring and be in the correct position each time. If the lift is in the wrong position, even by a few millimetres, it poses a serious falling hazard for the people working at that height.Two sets of sensors are required for detecting the position of platforms that must reach and stop at two different heights. The platform needs to be in the exact place specified at each level, so reliability is essential in this application as well. The sensors here are often mounted to the vehicle at the correct level as well as the platform, which is powered by hydraulic actuators. The platform is operated from the rear of the trailer by the person using the platform; no control over the platform position should be given to any other person for safety reasons. The position sensor not only stops the lift when it detects that the platform is in the right position, but can affect an alarm sound when the correct position has been reached and when the platform is in motion. This feature lets everyone know where the platform is at any given time.Luxury yachts may be a far cry from a haulage vehicle, but they employ similar technology in their tail ramps. The largest (and most expensive) cruising yachts often have a speedboat or jet skis stowed away for the passengers to have fun with, and in order to get to shore when the ship is too large to dock in a small island harbour. The ramps lower into the water and allow access straight into the sea for the smaller vehicles kept inside, and also allow these to be driven straight into the yacht on returning. Because of the shape of these yachts, the tail ramps do not go straight up and down, so instead of a linear non-contact sensor they often use tilt sensors to measure the position as the ramp moves on a hinge action. Non-contact tilt sensors are used as they are often submerged under the water, and still need to be able to function correctly. Article published on: 31/12/2016 Article last updated on: 31/12/2016