U-Shaped Door Lock Bolt Blocking Device

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Solution Overview

Problem

Existing door lock security devices are limited in their adaptability, as they primarily function with locks having an operating button and fail to effectively block bolt sliding for locks actuated by keys, rods, or tassels, lacking universality across different lock types.

Innovation Solution

A device featuring a U-shaped housing with horizontal and vertical parts, designed to fit over the bolt and striker plate, allowing the bolt to pass through while preventing sliding by positioning arms between the lock components and supporting the bolt's heel, ensuring the bolt remains locked.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a claw device is used to block lock button operation (as in FR539759), then security against outside manipulation is improved, but the device can only be used with locks having an operating button, reducing adaptability

Engineering Contradiction:

Improvesecurity against outside manipulationVSAvoidadaptability to different lock types

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The housing is designed with a universal structure that can accommodate multiple lock types (key locks, rod locks, tassel locks, button locks) through a single device configuration. The open front vertical part allows the housing to fit over various lock mechanisms while the rear vertical part provides consistent blocking functionality regardless of lock type.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

Instead of blocking the lock mechanism directly at its operating point (button, keyhole, etc.), the invention inverts the approach by placing the blocking structure at the bolt end, preventing bolt movement from the opposite direction. This allows the same housing structure to block various lock types uniformly.

Inventive Principle:

Principle #13The other way round (Inversion)

2Reliability

If a solid blocking structure is used to prevent bolt sliding, then security is improved, but the device cannot accommodate different lock configurations, reducing versatility

Engineering Contradiction:

Improveprevention of bolt slidingVSAvoidcompatibility with various lock configurations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The housing is segmented into distinct functional parts: a rear vertical part with solid blocking arms for preventing bolt sliding, and a front vertical part with open space for accommodating different lock mechanisms. This segmentation allows each part to perform its specific function while contributing to overall adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different parts of the housing have different structural qualities optimized for their specific functions: the rear vertical part has solid arms for blocking, while the front vertical part has open space for accommodation. This local differentiation of structural properties enables both effective blocking and universal adaptability.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3301246B1Device for blocking the opening of a door latch from the inside

Publication Date: 2019.12.25 MARTIN ROBERTSON & BAIN LTD

Figure 1~3
Figure 4

AI summary

The invention relates to a device for preventing the sliding of the bolt (1) of a door lock. It consists of a housing (2) in the shape of an inverted "U". The solid arm (6) prevents the bolt (1) from sliding. The arms (3, 3') at the other end of the device bear against the lock case (7) and resist the tension exerted by the bolt (1) on the solid arm (6) during an attempt to force the door open. The device according to the invention is particularly suited to a sliding lock not embedded in the door frame but mounted on the door frame.