Automatic pet door

An automatic door apparatus for installation in a wall of a building structure, for permitting an authorized pet to pass through the wall, the apparatus comprising:

• (a) a frame having a parallel-spaced pair of rigidly connected column members for mounting vertically oriented between studs of the wall, a lower portion of the frame defining a doorway passage between opposite sides of the wall;
• (b) a door member vertically movable in the frame between a lower closed position for closing the passage and an upper open position for opening the passage, each column of the frame having a channel formed therein for slidably guiding the door member;
• (c) drive means supported by the frame and coupled to the door member for lifting the door member from the closed position to the open position in response to a motor signal, the door member having a smooth horizontally oriented slot formed therein for engagement by the drive means, the drive means comprising:
• (i) an arm driven about a horizontal arm axis and having a crank pin fixably connected thereto in parallel spaced relation to the arm axis, the crank pin being slidably guided within the slot during operation of the drive means;
• and
• (ii) an electric motor operatively responsive to the drive signal and coupled through a clutch to the arm for rotation thereof about the arm axis, the clutch limiting an arm torque transmitted between the motor and the arm;
• (d) a radiation transmitter for wearing by the pet, the transmitter being operable for producing a predetermined transmitter signal concentrated within a transmitter bandwidth within an ultrasonic frequency range;
• (e) transducer means located proximate the frame for producing a transducer signal in response to the transmitter signal when the pet approaches the frame from one side of the wall and when the transmitter means is located at either side of the wall, the transducer means comprising a transducer unit supportively located by the frame proximate a lower extremity of the passage, proximately coplanar with the door member;
• (f) control means responsive to the transmitter signal for activating the motor signal, whereby the door member is raised by the drive means;
• (g) security locking means for preventing movement of the door member upwardly from the closed position until the motor signal is activated;
• (h) a first trim member for covering a first wall opening in a first side of the wall, the frame being received into the wall through the first wall opening;
• (i) a second trim member for covering edges of a second wall opening in a second, opposite side of the wall, the second wall opening being approximately aligned with the doorway passage;
• and
• (j) means for fastening the trim members to opposite sides of the frame, whereby the drive means and the control means are concealed within the wall.