Door Lock Pin Actuation and Spring Retraction Mechanism
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Solution Overview
Problem
Traditional door locks with electrical actuators face challenges such as slow retraction speeds, power requirements under load, and complex configuration for fail-open or fail-close modes, as well as jamming issues when the pin extends before alignment with the strike plate, especially for double swing doors.
Innovation Solution
A lock mechanism featuring a spring-biased pin with a latch system and motor-driven actuator that disengages from the pin in the extended position, allowing the spring to retract the pin, along with a controller for programmed locking and unlocking operations, and a linkage mechanism to manage forces and prevent jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If an electrical actuator is used to move the pin between retracted and extended positions, then the lock can be controlled remotely and configured for fail-open or fail-close modes, but the retraction speed becomes slow and power consumption increases under load
Solution Approach 1:
The locking mechanism is divided into two independent systems: a motor-driven actuator for extending the pin and a spring-driven mechanism for retracting it. This segmentation allows each component to be optimized for its specific function - the motor provides controlled extension while the spring delivers rapid retraction without power consumption concerns.
Solution Approach 2:
The system uses periodic engagement and disengagement of the motor with the pin through a ratchet mechanism. The motor extends the pin periodically, then disengages to allow spring-driven retraction, creating a rhythmic operation that alternates between powered extension and passive retraction phases.
2Power
If the motor moves the pin at relatively slow speed, then the actuator has sufficient power to move the pin under onerous conditions, but the locking operation takes longer time
Solution Approach 1:
The system separates the extension and retraction functions into different mechanisms with different performance characteristics. The motor provides high torque for extension under load, while the spring provides high speed for retraction, eliminating the need to compromise between speed and power in a single actuator.
Solution Approach 2:
The spring mechanism converts the potential harmful effect of slow motor retraction into a beneficial rapid retraction force. By using the spring's stored energy, the system transforms what would be a speed limitation into a performance advantage for the retraction phase.
3Reliability
If the pin extends before the lock is sufficiently aligned with the strike plate, then the door can be locked, but the pin jams the door in an open position
Solution Approach 1:
The system performs preliminary alignment by using the motor to slowly extend the pin only after the door is properly positioned. The controlled motor extension allows time for alignment verification before the pin engages the strike plate, preventing premature extension that would cause jamming.
Solution Approach 2:
The system incorporates feedback through sensors that monitor door position and alignment with the strike plate. This feedback controls the motor actuator to extend the pin only when proper alignment is detected, preventing jamming while ensuring reliable locking when the door is correctly positioned.
4Adaptability or versatility
If a lock for double swing door is designed to lock from either direction, then the lock is versatile, but the alignment and pin extension timing becomes more complex
Solution Approach 1:
The motor-driven actuator with controlled extension timing serves multiple functions: it extends the pin slowly for alignment verification, maintains the pin in intermediate positions during positioning, and enables locking from either direction of door swing. This single mechanism handles all alignment scenarios that would otherwise require separate mechanical systems.
Solution Approach 2:
The system uses dynamic control of the motor actuator to adapt to different door positions and swing directions. The motor can pause, reverse, or extend at variable speeds based on real-time feedback, allowing the same mechanism to handle multiple door configurations and swing directions without complex mechanical adjustments.
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 ensures efficient and reliable locking and unlocking operations, handles loads effectively, and simplifies configuration between fail-open and fail-close modes, while preventing pin jamming by using a spring-assisted retraction and a linkage to manage forces.
Implementation Method 1
a spring for biasing the pin to the retracted position
Data Source
AI summary
A lock for locking a door, the lock comprises a pin moveable between a retracted position and an extended position for locking the door and an actuator movable from a first position to a second position to move the pin from the retracted position to the extended position. Furthermore, the lock comprises a mechanism comprising a spring for biasing the pin to the retracted position and a latch. When in the latched position the latch prevents the pin from moving from the extended position to the retracted position, and when in an unlatched position the latch allows the pin to move from the extended position to the retracted position. The mechanism is adapted to disengage the actuator from the pin when the pin is in the extended position.