Door Latch Cam Assembly for Simultaneous Handle Retraction
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Solution Overview
Problem
Existing door locks often lack efficient mechanisms for smoothly transitioning between locked and unlocked states, particularly in situations where both inside and outside handles are used simultaneously, leading to mechanical interference and operational inefficiencies.
Innovation Solution
A latch assembly with an eccentric cam mechanism that allows for smooth retraction of the latch by rotating about a common axis, utilizing a roller sleeve to reduce friction and enable simultaneous operation of both handles, ensuring seamless transition between locked and unlocked states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional door lock mechanism is used, then the structure is simple, but the handles cannot operate simultaneously without mechanical interference
Solution Approach 1:
The latch mechanism employs a dynamic cam and follower system where the cam rotates about a fixed axis to convert rotational motion from either handle into linear retraction motion of the latch. This dynamic mechanism allows both handles to operate simultaneously without mechanical interference by translating their respective forces through the cam's rotational path.
Solution Approach 2:
The cam acts as an intermediary element between the two handles and the latch. When either the inside or outside handle is operated, the force is transmitted through the cam mechanism, which mediates the interaction and coordinates the latch retraction, preventing direct mechanical conflict between the two handles.
2Reliability
If a cam mechanism is used to enable simultaneous handle operation, then operational reliability improves, but manufacturing precision requirements increase
Solution Approach 1:
The cam mechanism utilizes curved surfaces and rounded profiles in its design. The cam's rotational path and the follower's contact surfaces are designed with specific curvatures that guide the motion and distribute contact forces, reducing sensitivity to minor manufacturing variations while maintaining reliable operation.
Solution Approach 2:
The design incorporates specific geometric parameters for the cam profile, including radius of curvature, center offset, and contact surface angles, which are optimized to provide smooth operation and reduce sensitivity to manufacturing tolerances. These parameter choices balance precision requirements with operational reliability.
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 eccentric cam mechanism facilitates smooth and efficient operation of the latch, reducing mechanical interference and enhancing operational reliability by allowing simultaneous use of both handles without jamming.
Implementation Method 1
utilizing a roller sleeve to reduce friction
Data Source
AI summary
A latch assembly comprises a housing, a latch movable at least partially within the housing from a retracted position to an extended position, and a cam rotatably secured to a cavity inside the housing. The latch comprises a cutout having two cam surfaces diverging from a back end to two front ends of the cam surfaces. The cam comprises a nose engaged with at least one cam surface at the back end when the latch is in the extended position, and engaged with one of the cam surfaces towards the front end of one of the cam surfaces.