Abstract: A pet door unit (10) for mounting in a structure (100) , is described. The unit includes a housing (12) , an opening mechanism (22) , a door (18) , a receiver (36) and a transmitter (38) . The door is mounted parallel to the rear wall (12D) of the housing in guide rails (16) extending along the sidewalls (12C) of the housing. The opening mechanism includes a motor (24) having a screw drive (26) and a carriage (34) which is movably mounted on the screw drive. The carriage is connected to the top of the pet door and moves along the length of the screw shaft (28) as the shaft rotates to open and close the door. To open the door, a user presses a button (38A) on the portable transmitter which sends a signal to the receiver. When the receiver receives the signal, it activates the opening mechanism which activates the motor to rotate the screw drive to move the carriage and the door up the shaft to the open position.

Abstract: A pet door unit having a housing, an opening mechanism, a pet door, a receiver and a portable transmitter. The opening mechanism includes a motor having a screw drive and a carriage. The carriage is connected to the top of the pet door and moves along the length of a screw shaft of the screw drive as the shaft rotates to open and close the door. A detector is mounted on each of the sidewalls of the housing to detect an object in the opening of the housing and prevent the door from closing when an object is detected in the opening. To open the door, a user presses a button on the portable transmitter which sends a signal to the receiver which activates the opening mechanism to move the door to the open position.