Pet Door Flap Locking via Over-Center Linkage
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Solution Overview
Problem
Existing pet doors face challenges in creating an effective locking mechanism that reliably latches the door flap regardless of its motion or location during re-latching, often requiring timed mechanisms to ensure correct positioning.
Innovation Solution
The use of an over-center 3-bar linkage system with a rotatable knob and magnetic attraction to control the flap's movement, combined with an electric motor and microprocessor for automatic locking and unlocking, ensures the door remains locked or unlocked regardless of external forces, and allows selective passage directions through the pet door.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timed locking mechanism is used to ensure the door flap is in the correct position before re-latching, then the reliability of the locking mechanism is improved, but the device complexity increases
Solution Approach 1:
The over-center 3-bar linkage system automatically positions the door flap correctly during the latching process without requiring external timing control. The mechanical geometry of the linkage ensures that when the latch engages, the flap is naturally in the correct position, eliminating the need for timed mechanisms or sensors to verify flap position.
Solution Approach 2:
The patent replaces electronic timing mechanisms and position sensors with a purely mechanical over-center linkage system. The linkage uses geometric constraints and mechanical advantage to ensure correct flap positioning during latching, substituting complex electronic control with simple mechanical design.
2Adaptability or versatility
If the locking mechanism must work regardless of the door flap's motion or location during re-latching, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The over-center 3-bar linkage system is designed to accommodate dynamic movement of the door flap during the latching process. The linkage can adjust to different flap positions and motion trajectories, maintaining reliable locking regardless of how the flap moves during engagement, making the system highly adaptable to various operating conditions.
3Ease of operation
If a rotatable knob with multiple portions is used to control flap movement in different directions, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
The rotatable knob is designed as a multi-functional control element that can restrict flap movement in different directions (inward, outward, both) depending on its rotational position. A single knob structure performs multiple locking functions, eliminating the need for separate controls for different directional restrictions and simplifying the overall user interface.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides secure and reliable automatic locking and unlocking of the pet door, preventing unwanted entry while allowing authorized animals to pass through, even under external forces like wind, and allows for manual operation in case of signal loss or battery issues.
Implementation Method 1
U.S. Pat. No. 5,469,659A utilizes a magnetic see-saw that actuates the latch when a pet with a magnetic collar enters the area where the magnetic see-saw is located.
Data Source
AI summary
A pet door is provided herein. The pet door includes a pivotal flap and a frame that defines a through-way. A rotatable knob is mounted to the frame and has a handle portion and a stop wall. The handle portion and stop wall include various profiles and configurations that work in concert to control the flap's direction of pivotal movement. In a first configuration, the flap may swing outwardly or inwardly. A second configuration prevents the flap from swinging inwardly. A third configuration prevents the flap from swinging outwardly. A fourth configuration places the flap is in a locked position to prevent swinging in either direction. The electronic door also includes an electronic latch mechanism which selectively latches and unlatches the flap. The latch mechanism unlatches the flap in response to a wireless signal from an electronic transmitter that may be affixed to a pet.