Lift-and-Slide Sash Locking for Burglar-Resistant Windows

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Solution Overview

Problem

Existing lift-and-slide devices for doors and windows are complex in design, requiring precise installation and adjustment, and lack effective burglar-resistant features.

Innovation Solution

A lift-and-slide mechanism with T-shaped and C-shaped locking elements that securely engage to prevent the sash from being lifted beyond the lowered position, featuring a simple and robust construction with minimal components and easy installation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking elements with multiple components are used, then burglary resistance is improved, but device complexity increases

Engineering Contradiction:
Improveburglary resistanceVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple locking functions into a single integrated locking element that performs both positioning and securing functions. The locking element integrates a positioning protrusion for vertical positioning and a locking protrusion for preventing lateral displacement, eliminating the need for separate locking components while maintaining comprehensive security functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking element is designed as a multi-functional component that simultaneously provides vertical positioning through the positioning protrusion, lateral security through the locking protrusion, and engagement with both the carriage and frame. This universal design reduces the total number of components needed while maintaining all necessary security functions.

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

2Reliability

If precise installation and adjustment of locking elements is performed, then burglary resistance is improved, but ease of manufacture deteriorates

Engineering Contradiction:
Improveburglary resistanceVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The locking element features localized geometric features (positioning protrusion and locking protrusion) with specific shapes and dimensions that provide secure engagement without requiring precise adjustment. The protrusions are designed with adequate clearance and engagement dimensions that ensure reliable locking while allowing for manufacturing tolerances and simple installation.

Inventive Principle:
Principle #3Local quality

3Reliability

If a large number of locking components are used, then burglary resistance is improved, but quantity of substance increases

Engineering Contradiction:
Improveburglary resistanceVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent consolidates multiple locking functions into a single integrated locking element that performs both positioning and securing functions. The locking element integrates a positioning protrusion for vertical positioning and a locking protrusion for preventing lateral displacement, eliminating the need for separate locking components while maintaining comprehensive security functionality.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4390027B1Lifting and sliding device
Publication Date: 2026.05.06 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP4390027B1 patent drawingFigure 1
  • EP4390027B1 patent drawingFigure 2
  • EP4390027B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a lift-and-slide device (10), in particular a lift-and-slide door or lift-and-slide window, with a frame (12) and a sash (16) which is movable relative to the frame (12) between an open position and a closed position along a sliding axis (z), and which is movable along a lifting axis (y) and relative to at least one carriage (20) supporting the sash (16) between a lowered position and a raised position, wherein at least one first locking element (44) connected to the frame (12) is provided and wherein a second locking element (34) is arranged on a part of the carriage (20) which is fixed along the lifting axis (z), wherein one of the locking elements (34, 44) has a T-shaped cross-section and the other locking element (44, 34) has a cross-section that is at least partially complementary to the T-shaped cross-section, in particular a C-shaped cross-section.wherein the second locking element (34) – in the closed position of the sash (16) and regardless of its position along the lifting axis (y) – engages under the at least one first locking element (44), so that the sash (16) is secured along the lifting axis (y) against being lifted beyond the raised position.