Defeater Latch Handle Dual Locking Mechanism
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Solution Overview
Problem
Prior defeater handles are overly complex and cumbersome to operate, requiring two hands and being prone to malfunction and high manufacturing costs, while lacking simplicity and robustness.
Innovation Solution
A defeater latch handle design featuring a rotatable lock, a slidable trigger with an extension catch, and a biasing device that allows the handle to be rotated only when both the lock and trigger are in their unlocked states, simplifying operation and enhancing security.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two separate locking features are used in defeater handles, then security level is improved, but device complexity and operational difficulty increase
Solution Approach 1:
The patent combines two separate locking features into a single integrated handle mechanism. The first locking feature uses a cam and latch assembly that engages with the door frame, while the second locking feature uses a trigger mechanism with a blocking device that prevents handle rotation. These two locking mechanisms are merged into one handle unit, providing dual security functionality without requiring two separate handles or excessively complex design.
Solution Approach 2:
The handle is divided into distinct functional segments: a handle body, a cam mechanism, a trigger mechanism, and a blocking device. Each segment performs a specific locking function, allowing the complex security requirements to be met through modular, manageable components rather than a monolithic complex structure.
2Reliability
If two separate locking features are used in defeater handles, then security level is improved, but ease of operation deteriorates
Solution Approach 1:
The trigger mechanism is pre-biased into a locked position by a spring, and the blocking device is automatically positioned to engage with the escutcheon. When the user pulls the trigger, the spring automatically returns the blocking device to its engaged position, providing the second locking action without requiring additional manual effort beyond the initial trigger pull.
Solution Approach 2:
Both locking actions (cam engagement and trigger blocking) are combined into a single handle operation sequence. The user operates one handle that simultaneously controls both locking mechanisms, eliminating the need to operate two separate handles or perform excessively complex manual steps.
3Reliability
If traditional defeater handle designs are used, then security features are provided, but manufacturing cost and susceptibility to malfunction increase
Solution Approach 1:
The handle is designed with modular segments (handle body, cam mechanism, trigger mechanism, blocking device) that can be manufactured separately using standard machining processes and then assembled. This segmentation allows for simpler individual components that are easier and less costly to manufacture compared to monolithic complex designs, while still providing the required dual locking security features.
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 design enhances security, reduces operational complexity, lowers manufacturing costs, and minimizes the risk of malfunction or failure over time, while maintaining robustness and ease of use.
Implementation Method 1
a biasing device to rotate the lock to its locked state
Data Source
AI summary
A defeater latch handle with a handle, a lock, and escutcheon. The handle has a through hole and a recess. The recess has a generally semi-circular ring portion and a recess notch portion that communicates with and extends out of the semi-circular ring portion. The lock is accessible through the cylinder hole. Opening the lock moves a movable blocking device to an unlocked state. The escutcheon has a bore formed therein. The bore has a notch formed therein that receives the blocking device when in its locked state. A trigger slot formed in the escutcheon receives a slidable trigger with an extension catch. In a locked state, the extension catch is in the recess notch. In an unlocked state, the extension catch moves out of the recess notch and into the semi-circular ring portion. The handle can only be turned when both the lock and the slidable trigger are unlocked.