Lever Mechanism Safety Device for Sudden Door Closure
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Solution Overview
Problem
Existing safety devices for preventing sudden door closures are complex, bulky, and inefficient, often only slowing down the closing process rather than fully stopping it, and require significant space for installation, posing risks to safety and structure integrity, especially with heavy doors like fire or armor-plated doors.
Innovation Solution
A safety device utilizing a lever mechanism with two articulated levers and elastic members of different elastic constants, where a clamping member engages to stop the door only when an impulsive force exceeding a certain threshold is applied, allowing gentle closure otherwise, and is designed to occupy minimal space when the door is closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If axial sliding mechanism with springs is used to prevent sudden door closing, then safety function is achieved, but device becomes bulky and requires significant installation space
Solution Approach 1:
The safety device is divided into two independent levers (first lever and second lever) that can be activated separately. The first lever handles normal closing operations while the second lever engages only during sudden closing events, allowing the device to remain compact while maintaining safety functionality.
Solution Approach 2:
The device uses dynamic activation of different levers based on the closing conditions. During normal closing, only the first lever is active. When sudden closing is detected through excessive force, the second lever dynamically engages to block the door, providing adaptive response without requiring constant bulky blocking mechanisms.
2Reliability
If complex mechanical safety mechanisms are used, then door closing control is achieved, but device complexity increases with large number of components
Solution Approach 1:
The control function is segmented between two levers with distinct roles. The first lever manages normal operation with simple spring-based return, while the second lever provides emergency blocking. This segmentation allows each component to be simple while the combination achieves complex control functionality.
Solution Approach 2:
The second lever acts as an intermediary blocking element that is activated only when necessary. It mediates between the door's closing force and the frame, providing a simple binary state (blocked or not blocked) that adds safety functionality without requiring complex control systems.
3Reliability
If safety device blocks door during closing, then sudden closing is prevented, but device must be bulky to ensure blocking capability
Solution Approach 1:
The blocking capability is achieved dynamically through the second lever that engages only when sudden closing force is detected. The lever rotates from a retracted position to a blocking position, providing full blocking capability only when needed. This dynamic approach allows compact design while maintaining effective blocking when activated.
Solution Approach 2:
The second lever is pre-positioned in a retracted state that does not interfere with normal door operation. When sudden closing occurs, the lever is rapidly rotated into the blocking position. This preliminary positioning allows the device to maintain compact size while being ready to provide full blocking capability when required.
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
Effectively prevents sudden door closures by engaging a clamping mechanism only under high impulsive forces, ensuring safety and reliability while allowing normal closure, and is compact enough for easy installation on the fixed frame, reducing the risk of damage and injury.
Implementation Method 1
at least two elastic members, with a different elastic constant
Implementation Method 2
thrust toward an open position by a pair of helical springs
Data Source
AI summary
Safety device (10, 1 10, 210) to prevent the sudden closing of a movable element, such as a closing element of a piece of furniture or a door, comprising a lever mechanism (20, 120, 220) which in turn comprises an actuation lever (11, 11 1, 211), which can rotate with respect to a pin (12, 112, 215) between an open position and a clamping position, or alternatively, a closed position. A first elastic member (25, 125, 225) able to apply a first elastic force (R1) and a second elastic member (30, 130, 230) able to apply a second elastic force (R2), less than the first elastic force (R1), act on the mechanism lever (20, 120, 220).