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A sliding door operator (or sliding door opener or automatic sliding door operator) is a device that operates a sliding door for pedestrian use. It opens the door automatically, waits, then closes it.
Contents
Uses
Sliding door operators are typically used on the outside doors of large retail businesses. (smaller retail businesses prefer swing door operators.) They are also used in elevators (lifts)
Triggering
A door operator may be triggered in various ways:
A trigger from any of the above requests that the door be opened (or reopened if it was closing).
Safety sensors
A sliding door operator reopens the door if it closes into an obstacle. However, most operators use sensors to prevent the door from ever coming into contact with a user in the first place.
The simplest sensor is a light beam across the opening. An obstacle in the path of the closing door breaks the beam, indicating its presence. Infrared and radar safety sensors are also commonly used.
Collision Detection
In the instance that an object is not detected by a safety beam or curtain, the BLDC motor can detect the resistance of the door pushing on the object. If such resistance is found, the door opens back up.
Technology
The operator is placed in the space above the sliding door.
An electric motor, geared down to get a lower speed and a higher torque, drives a pulley at one end of a belt. The door is clamped to the belt. To open the door, the motor turns the pulley, which in turn turns the belt, which in turn drags the door. To close the door, the reverse occurs.
Historically, elevator doors were opened by a set of mechanical linkages; the motor, geared down, would rotate linked arms, which in turn would drive the door.
Types
There are several types of sliding doors, these are: