Door Lock Sensor Using Non-Magnetic Faceplate for Reliable Detection
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Solution Overview
Problem
Existing door locks with integrated electronics face challenges in accurately determining whether a door is open or closed due to limited space for sensors, interference from magnetic materials, and the need for external sensors that are difficult to install and secure, especially in high-security applications where a deadbolt is required.
Innovation Solution
A door lock design incorporating a magnetically actuated door position sensor with rectangular magnets and a non-magnetic faceplate, allowing the sensor to be mounted in limited space alongside a deadbolt, and using a beveled or stepped mounting opening to enhance magnetic field penetration, ensuring reliable detection of the door's position without omitting the deadbolt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a door position sensor is integrated into the lock mechanism, then installation is simpler and the sensor is more secure, but the available space for the sensor is limited
Solution Approach 1:
The door position sensor is nested within the existing lock mechanism structure, specifically utilizing the space around the latchbolt and within the faceplate assembly. The sensor is positioned to detect the door edge through the strike plate openings without requiring additional external mounting space.
Solution Approach 2:
The sensor is positioned to detect the door edge through the existing strike plate openings, utilizing the depth dimension and the space between the faceplate and strike plate rather than requiring additional lateral or vertical space on the door surface.
2Reliability
If a magnetic sensor is integrated into the lock, then the sensor is more rugged and less visible, but lock components made of magnetic materials interfere with the operation of the sensor
Solution Approach 1:
The magnetic interference from steel components is extracted and eliminated by using a non-magnetic faceplate material (such as aluminum or plastic) in the areas where the magnetic sensor is positioned, creating a clear magnetic field path from the sensor to the door edge.
Solution Approach 2:
A non-magnetic intermediary material (the non-magnetic faceplate) is introduced between the magnetic sensor and the magnetic steel components of the lock mechanism, allowing the magnetic field to pass through the faceplate to detect the door edge without being blocked by the magnetic materials.
3Area of stationary object
If the sensor is positioned where the deadbolt is normally installed, then space is made available for the sensor, but the lock becomes less secure
Solution Approach 1:
The faceplate is designed to accommodate multiple functions simultaneously: the deadbolt function is maintained through the deadbolt opening, while the door position sensing function is integrated through the sensor opening and the non-magnetic material that allows magnetic field penetration for edge detection.
Solution Approach 2:
The faceplate is segmented with separate openings for the deadbolt and the door position sensor, allowing both the deadbolt security function and the sensor detection function to operate independently without interfering with each other.
4Strength
If the strike is made of steel, then it is strong and durable, but it interferes with the magnetic field from the sensor
Solution Approach 1:
The strike plate is designed with local quality variations: the majority of the strike plate can be made of steel for strength and durability, while specific areas (particularly around the openings and the region where the magnetic field passes through) are made non-magnetic to allow magnetic field penetration for sensor operation.
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
The solution enables reliable detection of the door's position within industry-standard dimensions, maintaining high-security standards by hiding the magnets and sensors, and allowing for retrofitting in existing lock designs, even with larger gaps between the door and strike.
Implementation Method 1
A magnetically actuated door position sensor with rectangular magnets and a non-magnetic faceplate, allowing the sensor to be mounted in limited space alongside a deadbolt
Data Source
AI summary
A door lock with integrated door position sensor includes rectangular magnets positioned behind the door strike to maximize magnetic field strength in available space limited by industry-standard dimensions for the door strike. A beveled or stepped mounting opening for the sensor is formed in a front plate of the door lock and behind a non-magnetic faceplate. The shape of the mounting opening allows the magnetic field to penetrate deeply through the faceplate and front plate to actuate the door position sensor. The sensor may be used in mortise locks or bored locks. In an alternative embodiment, the sensor is spring mounted to eliminate all mounting tolerances and ensure that the sensor is maximally forward and flush against the back of the non-magnetic faceplate.