Optic Technology for the Entrapment Issues of Side of Step, Comb Plate and Lift Doors

Stephen Williams and Johan Sevenants

Wednesday 23rd September 2015

This paper describes the prevalent issues that are apparent with side of step, comb plate and lift doors and how a better solution can be introduced. There have for many years been designs which have partly solved the problem, but are generally mechanically biased and in some cases are not used at all by the manufactures, as is the case of skirt panel detection and lift doors. Due to the increased number of reported incidents and the recent fatalities of strangulation, some consumers have developed an unbiased opinion that escalators and lift doors are dangerous. It has become more apparent that safety at the main entrapment points of skirt panel, comb plates and lift doors can be increased to be more reliable and functional with optic technology. Step to skirting panel entrapment has been for many years a major incident issue, and only recently a small boy in the UK had an incident on an escalator and got his hand caught at this such point. With reference to the comb bearer, incidents of entrapment have resulted in fatalities in Canada and Belgium. Issues of entrapment are caused by the type of footwear i.e. crocks and clothing. A scenic lift door is a viewing area especially for small children, resting their hands on the glass. As the car arrives the doors open, the fingers have the potential to become trapped at the door frame. These three main trapping points would undergo their regular maintenance schedule and the relevant safety checks would be carried out, with the equipment within its recommended tolerances. But with all moving parts the potential for entrapment is possible. An optic cable installed into a module unit, sending a light signal out and monitored on its return for any distortion, has the function ability to assist with eliminating these potential trapping points. A light signal is monitored going out to its return on a multitude of parameters within the module box. When a pre-set distortion point has been reached, “which can be as sensitive as 0.01mm of movement”, a signal will be sent immediately to stop the unit at its safety function. The sensitivity of this function is due to the self-calibrating function in the system.

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