Spring Latch Composite Design for Friction Reduction
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Solution Overview
Problem
Metallic spring latches experience significant friction and jamming issues when sliding on metallic plates and strike plates, leading to compromised operation and potential failure in locking mechanisms.
Innovation Solution
A spring latch design incorporating a metallic central portion with upper and lower plastic portions that reduce friction by ensuring only plastic surfaces contact the plates, featuring guiding ridges for precise motion and a dovetail cross-section for secure integration, allowing for fluid and continuous retraction and advancement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the spring latch is made entirely of metallic material, then resistance to impacts and break-in attempts is improved, but friction between the spring latch and the plate/strike plate increases causing jamming
Solution Approach 1:
The spring latch is constructed as a composite object with a metallic central insert providing strength and resistance to impacts, while plastic portions covering the sliding surfaces reduce friction with the plate and strike plate. This composite structure resolves the contradiction by combining materials with complementary properties - metal for strength and plastic for low-friction operation.
Solution Approach 2:
Different portions of the spring latch have different material properties tailored to their specific functions: the central portion is metallic for structural strength, while the portions contacting the plate and strike plate are plastic for reduced friction. This local differentiation of material quality allows the single object to simultaneously achieve both strength and operational fluidity.
2Ease of operation
If the spring latch has a central insert made of plastic material, then gliding on the strike plate is improved, but friction on the plate remains compromised
Solution Approach 1:
The spring latch is segmented into distinct functional portions: a central metallic insert and separate plastic portions that cover the sliding surfaces. This segmentation allows each portion to be optimized for its specific function - the plastic portions specifically address the gliding interface with the plate, while the metallic center provides overall structural integrity.
3Reliability
If the spring latch uses plastic portions, then friction is reduced, but the metallic portion is still exposed to potential contact with plate edges
Solution Approach 1:
The plastic portions are merged with the metallic central insert to form an integrated spring latch structure. The plastic portions extend from and are connected to the metallic center, creating a unified object where the metallic portion is protected by the plastic covering during normal operation, reducing direct exposure to plate edges while maintaining structural coherence.
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 significantly reduces friction and jamming, ensuring smooth operation, maintaining security equivalent to all-metallic latches while being easier to install and reducing noise during closure.
Implementation Method 1
a pusher spring; when the leaf is closed after being open, the spring latch either is made to retract by means of the actuation of an associated handle or, during the closure rotation of the leaf, encounters an edge of a fixed frame of the same door or window to which the leaf belongs, and retracts inside the leaf to then advance, by virtue of the thrust of the spring
Implementation Method 2
The sliding of the spring latch on the edges of the corresponding openings on the plate and the strike plate can cause jamming of the spring latch due to friction between the metal of the plate and the metal of the spring latch
Data Source
Figure 1~2
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AI summary
A spring latch (10) for locks, comprising a metallic portion (11) and at least one portion (12) made of plastic material; - the metallic portion (11) forms a central part of the spring latch, - there are two portions (12, 13) made of plastic material, an upper portion (12) and a lower portion (13), with respect to a configuration for use, - the upper portion (12) and the lower portion (13) protrude outward, with respective external surfaces (14, 15, 16, 17, 18, 19), with respect to corresponding external surfaces (20, 21, 22, 23) of the central metallic portion (11).