Locking Device Catch Prevents Latch Bolt Rotation

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Solution Overview

Problem

Existing pivotable latch bolts in locking devices face issues such as potential breakage under forced entry attempts, increased space and cost requirements for sturdy components, and challenges in complying with fire regulations by ensuring doors can be closed in emergencies.

Innovation Solution

A locking device with a latch bolt that rotates and retracts, featuring a catch that blocks rotation and retraction, allowing for compact and cost-efficient design while preventing unauthorized door opening and ensuring door closure in emergencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the latch bolt is made sturdy and strong to prevent breakage under forced entry, then the reliability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improveresistance to forced entryVSAvoidcomponent size and structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is divided into multiple functional components: a latch bolt for primary locking, a catch mechanism for blocking rotation, and a bolt latch for supporting the bolt. This segmentation allows each component to be optimized independently, using smaller, less complex parts while maintaining overall system reliability through coordinated function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The catch acts as an intermediary component between the latch bolt and the door frame. Instead of requiring the latch bolt itself to resist all forcing forces, the catch serves as a mediator that blocks rotation and transfers forces to the face plate, allowing the latch bolt to be smaller and less complex.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the latch bolt is made sturdy and strong to prevent breakage under forced entry, then the reliability is improved, but the manufacturing cost increases

Engineering Contradiction:

Improveresistance to forced entryVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By segmenting the locking function across multiple components (latch bolt, catch, bolt latch), each part can be manufactured separately using simpler, more cost-effective processes. The face plate can be a simple stamped or cast piece, while the latch bolt and catch can be smaller extrusions or forgings, reducing overall material and manufacturing costs.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The design allows for the use of simpler, potentially replaceable components rather than requiring one large expensive locking mechanism. If a component fails under forced entry, individual parts like the catch or latch bolt can be replaced rather than replacing the entire locking device, reducing long-term costs.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If the catch blocks both rotation and retraction to prevent unauthorized opening, then the security is improved, but the ease of operation deteriorates

Engineering Contradiction:

Improveprevention of unauthorized openingVSAvoiddoor closure in emergency

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The catch mechanism is designed to be dynamic rather than fixed. It can be engaged to block both rotation and retraction under normal conditions, but can be disengaged when needed. This allows the system to adapt between security mode (both movements blocked) and emergency mode (retraction allowed for door closure), maintaining both security and ease of operation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The catch alternates between engaged and disengaged states based on operational needs. During normal operation, it remains engaged to prevent unauthorized opening. During emergency egress or maintenance, it can be temporarily disengaged to allow door closure, then re-engaged afterward. This periodic engagement/disengagement provides both security and operational flexibility.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20250027335A1Locking device with a catch for preventing rotation of a latch bolt

Publication Date: 2025.01.23 STENDALS ELEKTRISKA AB

AI summary

The present invention relates to a locking device comprisingan elongated face plate (30) for mounting on a door, the face plate comprising an opening (31) for a latch bolt,a latch bolt (10) having a bolt body (11) with a first end (11A) and a second end (11B), the bolt body (11) comprising a first surface (12) and a second surface (13) that are on opposite sides of the first end (11A), wherein the latch bolt (10) is configured to move from an extended position with the first end (11A) protruding from the opening (31) in the face plate (30) to a retracted position, and wherein the bolt body (11) is further configured to rotate around an axis that is parallel to the face plate (30) in response to a force applied to the first surface (12), and wherein further the second surface (13) is curved for sliding along an edge (33) of the opening (31) in the face plate (30) during rotation of the bolt body (11),and the locking device (1) further comprisinga first blocking surface (14) on the second end (11B) of the latch bolt (10), anda first catch (22) movable to a blocking position in which the first catch (22) engages the first blocking surface (14) for preventing the rotation of the bolt body (11).