Automatic Sliding Door

Overview

An automatic sliding door is a powered pedestrian entrance in which two glass leaves slide apart on the approach of a person and close again once the threshold is clear. The complete unit hangs from a header beam mounted above the opening; nothing touches the floor except a guide channel. It is the standard entrance for retail, healthcare, hospitality and office buildings because it is hands-free, weather-sealing and high-traffic rated.

The system is built around the Operator Header Beam, an extruded aluminium beam that spans the opening and houses every working part behind a removable cover. Inside it sit the drive, the running track and the controller.

How it works

Motion is produced by the Belt Drive Unit. A brushless DC motor turns a toothed pulley through a single-stage reduction gearbox; the pulley drives a timing belt that loops the length of the header to a spring-loaded idler tensioner at the far end. Each glass Door Panel (Leaf) hangs from an Door Hanger Carriage, a trolley whose nylon roller wheels run along the Track & Guide Rail and whose belt clamp couples it to one run of the belt, so the two leaves part and meet symmetrically.

The Door Controller runs the motion profile, ramping speed up and down so the leaves accelerate smoothly and decelerate before the end stops. It takes its triggers from the Sensor Set: overhead microwave heads detect an approaching pedestrian and command an opening, while active-infrared presence curtains hold the door open as long as anyone occupies the threshold, preventing the leaves from closing on a person.

When the building is secured, the Electric Lock throws a solenoid bolt into a strike at the meeting stile. The fail-safe lock releases on power loss so the door can never trap occupants. To keep the door operable during an outage, the Battery Backup Unit holds a charged 18650 pack and a failover board that either drives the door fully open or maintains the locked state, according to the programmed mode.