Automatic door actuator

An automatic door actuator which is energized by an external power supply in response to turning-on of a power switch and which comprises a door, motor means coupled to said door to open and close said door, semiconductor controlled rectifying means for selectively connecting said motor means to the external power supply at a controlled phase angle to control a rotating velocity of said motor means, and control means operable, when activated, to supply a trigger signal at a controlled phase angle to said semiconductor controlled rectifying means to activate said semiconductor controlled rectifying means;

• wherein said actuator further comprises:
• arithmetic means for calculating a weight of said door, distance of movement of said door and braking points of said door through learn control of door actuation which is effected once every time said power switch is turned on and irrespective of the on-off condition of said start switch;
• first memory means for storing results of calculation by said arithmetic means;
• second memory means for previously storing various phase angles for starting operation, for deceleration braking operation, and for predetermined low velocity control, corresponding to various weights of said door;
• and
• said control means being responsive to said first memory means to read out from said second memory means the phase angles for starting operation, for deceleration braking operation and for predetermined low velocity control corresponding to the actual weight of said door determined in said learn control to thereby supply the trigger signal to said semiconductor controlled rectifying means in accordance with the read-out phase angles corresponding to the actual door weight and the distance of movement of said door and the braking points of said door determined in said learn control.