Switch Lock Lever Bridging Gap for Reliable Latch Engagement

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Solution Overview

Problem

Existing switch locks for strike boxes or mortise locks are complex and lack a reliable mechanism to ensure smooth switching functions between the retracted and locking positions without getting stuck in the pre-latched position.

Innovation Solution

A simplified switch lock design featuring a locking lever with a bridging area and insertion bevel that automatically pivots into a lever receptacle upon retraction, combined with spring-loading for secure engagement and disengagement, and anti-manipulation stops to prevent unauthorized use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional switch lock with multi-part bolt guide and spring-loaded switching element is used, then the locking function is achieved, but the device complexity increases due to many individual components

Engineering Contradiction:
Improvelocking functionVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking lever, bridging area, and insertion bevel into a single integrated component. The locking lever serves multiple functions: it bridges the gap between forend and striking plate, provides insertion geometry for smooth engagement, and enables automatic resetting. This merging of functions reduces the number of individual components while maintaining the reliable locking function.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking lever is designed as a multi-functional element that simultaneously performs gap bridging, provides insertion geometry for the striking plate opening, enables automatic resetting through the bridging area, and maintains structural support. This universal design eliminates the need for separate components for each function, reducing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If the latch bolt moves from pre-latched to retracted position, then the locking lever should reset automatically, but the locking lever may swing out and get stuck during upward movement

Engineering Contradiction:
Improveautomatic resettingVSAvoidswitching reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking lever is pre-configured with the bridging area and insertion bevel geometry before operation. The insertion bevel is designed to guide the locking lever into the opening of the striking plate during upward movement, preventing premature swinging out. The bridging area is positioned to bridge the gap between forend and striking plate, ensuring the locking lever remains constrained during the transition from pre-latched to retracted position.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bridging area acts as an intermediary element between the locking lever and the gap between forend and striking plate. By physically bridging this gap, the locking lever prevents the space from allowing unwanted movement or swinging out during the upward movement, ensuring reliable automatic resetting without getting stuck.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the gap between forend and striking plate is not bridged, then the locking lever can move freely, but the locking lever may swing out during upward movement and fail to lock properly

Engineering Contradiction:
Improvelocking lever movementVSAvoidlocking engagement
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The locking lever has different geometric features at different locations: the bridging area is designed with specific geometry to bridge the gap between forend and striking plate, while the insertion bevel at the free end is designed with different geometry to facilitate smooth insertion into the striking plate opening. This local differentiation of geometry ensures the locking lever maintains reliability during movement while allowing necessary adaptability.

Inventive Principle:
Principle #3Local quality

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

Ensures reliable switching between retracted and locking positions without getting stuck, simplifies the lock's structure by eliminating internal springs, and enhances security through automatic resetting and anti-manipulation features.

Implementation Method 1

the locking lever is spring-loaded. The spring loading is preferably such that the latching lever is pivoted out of the lever receptacle

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

a spring element acting on the pivoting-in side of the locking lever is preferably provided on the latch bolt. The spring element can be a torsion spring that acts on the pivoting side of the locking lever

Methodology Applied
Scientific EffectTorsion spring: Torsion Spring

Data Source

PatentEP2746506B1Trigger lock
Publication Date: 2016.09.21 WILH SCHLECHTENDAHL & SOEHNE GMBH & CO KG
  • EP2746506B1 patent drawingFigure 1~2
  • EP2746506B1 patent drawingFigure 3~5
  • EP2746506B1 patent drawingFigure 6~7

AI summary

The invention relates to a switch lock (3), in particular for a strike plate (2) or a mortise lock, wherein the switch lock (3) can be coupled to the strike plate (2) or the mortise lock via a drive rod (4), for use in the upper area of ​​a door, gate, or window, for interaction with a frame-side strike plate (5), with a latch bolt (8) guided in a bolt guide (7), which is movable between a locking position engaging in the strike plate (5) and a retracted position drawn into the bolt guide (7). According to the invention, a locking lever (9) is pivotably mounted on the latch bolt (8), which interacts with the bolt guide (7) in a pre-locking position between the retracted position and the locking position and holds the latch bolt (8) in the pre-locking position.