Double-Leaf Door Lock Mechanism Using Rack and Pinion
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Solution Overview
Problem
Conventional lock mechanisms for double-leaf doors, especially those with emergency opening devices, are mechanically complex and require delicate components like springs and elastic means, making them difficult to actuate securely and efficiently.
Innovation Solution
A lock design featuring a box-like body with a movement cylinder, rotating bushing, and lever mechanisms that utilize a pinion and rack system to facilitate the translation of spring and sliding latches, eliminating the need for delicate components and reducing mechanical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lock mechanisms with spring latches and sliding latches are used, then the door can be securely locked, but the mechanism becomes mechanically complex and requires delicate components like springs and elastic means
Solution Approach 1:
The patent extracts and eliminates the spring component from the lock mechanism. The sliding latch is designed to be held in the retracted position by a cam surface that guides a lever, rather than being held out by a spring. This removes the delicate elastic component while maintaining the secure locking function through the cam-lever arrangement.
Solution Approach 2:
The lock mechanism is segmented into distinct functional components: the sliding latch for primary engagement, the lever for translation motion, the cam surface for positioning, and the guide for constrained movement. Each segment performs a specific function, simplifying the overall mechanism while maintaining reliability.
2Reliability
If multiple mechanical linkages are used to control the latches, then the door can be locked securely, but the force required to actuate the lock increases and operation becomes difficult
Solution Approach 1:
The cam surface acts as an intermediary between the lever and the sliding latch. When the lever is pushed, the cam surface translates this motion into the appropriate movement of the sliding latch with mechanical advantage, reducing the force required at the handle while ensuring secure engagement.
Solution Approach 2:
The mechanism uses dynamic motion through the lever's rotation and the cam's profile to transform a small input force at the handle into the larger force needed to engage the latch securely. The cam's geometric profile provides mechanical advantage that varies during the actuation cycle.
3Reliability
If delicate components like springs and elastic means are used, then the lock can maintain secure closure, but the cost increases and implementation becomes more difficult
Solution Approach 1:
The patent replaces expensive, delicate spring components with simpler, more durable cam and lever mechanisms made from standard materials. The cam surface can be formed directly into the lever or as a separate hardened component, eliminating the need for precision spring manufacturing and reducing overall implementation cost.
Solution Approach 2:
The elastic mechanical system (springs) is substituted with a rigid mechanical system (cam and lever). This substitution eliminates the need for elastic components while achieving the same functional result of holding the latch in position, simplifying manufacturing and improving durability.
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 results in a mechanically simple, easy-to-actuate, and cost-effective lock that is secure and safe to use, with a reduced number of components, ensuring efficient operation without relying on springs or elastic means.
Implementation Method 1
a pinion (12) which is pivoted to a wall of said box-like body, said pinion meshing with a rack (13) of an actuation rod (5)
Implementation Method 2
a lever (11) which is integral with the pinion (12), a guide (9) for a head (10) of the lever (11)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A lock (1) for universal leaf doors comprising a box-like body (2) for containing a movement cylinder (3) which is associated with a respective actuation key, a rotating bushing (4) which is associated with a handle, lever mechanisms (5) for the translation of at least one spring latch (6) and of at least one sliding latch (7), which are functionally associated with the handle and with the cylinder (3); the sliding latch (7) comprises a pin (8) which can move between a protruding configuration and a retracted configuration; the sliding latch (7) is locked in the extracted configuration when the pin (8) is protruding and it is free, for a forced retraction by an external force, when the pin (8) is pressed in retraction by an external force; the sliding latch (7) comprises a guide (9) for the head (10) of a lever (11) which is integral with a pinion (12) which is pivoted to a wall of the box-like body (2); the pinion (12) meshes with a rack (13) of an actuation rod (5) which is coupled to the movement cylinder (3) and to the rotating bushing (4) which is associated with the handle; in the closed configuration of the lock (1) the head (10) of the lever (11) is accommodated in a limit area of the guide (9) with consequent locking of the retraction of the sliding latch (7); the pin (8) can abut, directly or indirectly, on the head (10) of the lever (11); in the event of the pin (8) being forced toward the retracted configuration thereof, this entrains the head (10) beyond the limit area of the guide (9) with consequent release of the sliding latch (7) for a retraction thereof as a consequence of applications of force from outside.