Spring-Assisted Mechanism for Raising and Lowering a Load

An apparatus for selectively permitting the passage of pets, the apparatus comprising:

• a base structure;
• a panel carried by the base structure for movement between an open position and a closed position;
• a motor carried by the base structure, the motor having an output shaft;
• a constant tension spring having a first end and a second end, the first end of the spring attached to the output shaft of the motor, the second end attached to the panel, the spring biasing the panel into the open position;
• and
• a control system in communication with the motor to actuate the motor and rotate the output shaft to move the panel from the closed position to the open position.

A system for selectively permitting the passage of pets, the system comprising:

• a frame;
• a sliding door carried within the frame for movement between an open position and a closed position;
• a motor carried by the frame, the motor having an output shaft;
• a constant tension spring attached to the door, the spring biasing the door into the open position;
• a control system in communication with the motor to actuate the motor and rotate the output shaft, thereby sliding the door from the closed position to the open position;
• a radio frequency antenna carried by the door;
• and
• at least one fob in communication with the antenna for signaling the control system to actuate the motor.

An apparatus for selectively permitting the passage of pets, the apparatus comprising:

• a frame;
• a sliding door carried by the frame for movement between an open position and a closed position;
• a motor carried by the frame and operably connected to the sliding door to move the sliding door into the open position from the closed position;
• a control system in communication with the motor to actuate the motor, thereby sliding the door from the closed position to the open position;
• and
• a radio frequency antenna carried by the door.

An apparatus for selectively permitting the passage of pets, the apparatus comprising:

• a frame defining an opening
• a sliding door carried within the opening for movement between an open position and a closed position;
• a seal carried by the frame between the frame and the sliding door at least when the sliding door is in the closed position;
• and
• a motor carried by the frame and operably connected to the sliding door to move the sliding door into the open position from the closed position.

A system for selectively permitting the passage of pets, the system comprising:

• a frame;
• a sliding door carried within the frame for movement between an open position and a closed position;
• a motor carried by the frame, the motor having an output shaft;
• a control system in communication with the motor to actuate the motor and rotate the output shaft, thereby sliding the door from the closed position to the open position;
• and
• a radio frequency antenna carried by one of the frame and the door, the radio frequency antenna operating at a low frequency of between approximately 90 KHz and approximately 200 KHz.