Window Sash Locking Mechanism with Rod and Latch System

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Solution Overview

Problem

Conventional window casing devices with hung sash fail to securely lock the sash in the open position, especially under strong winds, and are difficult to disengage for maintenance, requiring specialized tools and trained personnel.

Innovation Solution

A device with a rod and latches system, actuated by a handle, that limits the hung sash's opening through a roto-translation mechanism, allowing easy locking and unlocking by aligning a pin within a C-shaped slot, and includes a disengagement system using a key for complete opening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an arm is used to limit the opening of the hung sash, then the opening angle is controlled, but the locking stability in open position is insufficient under strong wind conditions

Engineering Contradiction:
Improveopening angle controlVSAvoidlocking stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

A rod acts as an intermediary element connecting the handle to the arm, translating rotational motion into linear motion that controls the arm's position. This mediator provides stable mechanical linkage and reliable positioning of the hung sash in the open state, preventing accidental closing under wind pressure

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The device enables self-locking through the interaction between the rod, arm, and handle mechanism. When the handle is rotated, the rod automatically positions the arm to limit the opening angle and lock the sash in place without requiring additional locking actions or complex mechanisms

Inventive Principle:
Principle #25Self-service

2Reliability

If locking means are added to secure the hung sash in open position, then safety is improved, but the device complexity and difficulty of disengagement for maintenance increase

Engineering Contradiction:
Improvelocking safetyVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking function is merged with the existing opening/closing mechanism. The same rod and handle that control the arm's positioning for opening angle limitation also provide the locking action. This integration eliminates separate locking components and simplifies the overall structure while maintaining reliable locking safety

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rod serves multiple functions: it translates handle rotation to control the arm's position for opening limitation, provides locking action to secure the sash in open position, and enables easy disengagement for maintenance. This multi-functionality reduces the need for separate components and simplifies the device structure

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

3Reliability

If a transmission system is used to convert vertical movement into locking action on the arm, then locking functionality is achieved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvelocking functionalityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The complex transmission system converting vertical to rotational motion is extracted and replaced with a simplified rod mechanism that directly translates handle rotation into arm positioning. This extraction removes unnecessary mechanical complexity while maintaining the essential locking functionality through a simpler, more manufacturable design

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2927404B1Device for the opening/closing of a window casing, with a stop member for the hung sash in the open position
Publication Date: 2019.06.26 FAPIM SPA
  • EP2927404B1 patent drawingFigure 1A~1C
  • EP2927404B1 patent drawingFigure 2
  • EP2927404B1 patent drawingFigure 3A~3B

AI summary

A window casing comprising a fixed frame (1) and a hung sash (2) and an opening/closing device. The device comprises an arm (9) pivotably fixed to the frame (1), and roto-translationally attached to upright (21) of the sash (2). A rod (4) slides along the upright (21) driven by handle (3) and drives latch means (5) in/out of engagement means (6) mounted on the frame (1) . The rod (4) comprises locking means (8, 80) suitable to engage with arm (9) when the rod moves towards locking position, thus blocking the arm (9) from sliding and locking the sash (2) in open position.