Cupboard Pull-Out Latching Assembly for Tool-Free Frame Locking

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Solution Overview

Problem

Conventional pull-out devices for tall cupboards require time-consuming assembly steps and have impractical locking mechanisms that are difficult to unlock, as the locking mechanism is hidden and not easily visible.

Innovation Solution

A pull-out device with a holder that can be locked and secured to the frame or pull-out element without tools, featuring a vertically aligned latching element that snaps into a counter-lock, a keyhole-like recess, and a spring-loaded mechanism for secure connection and easy height adjustment, allowing visible unlocking and preventing unintentional unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional tool-based fastening means are used to connect the frame to the pull-out element, then secure connection is achieved, but assembly time increases and work steps become time-consuming

Engineering Contradiction:
Improveassembly speedVSAvoidassembly simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The patent replaces conventional tool-based mechanical fastening (screws, bolts requiring screwdrivers or wrenches) with a cam-based locking mechanism that operates through leveraging motion. The cam profile converts rotational or linear motion into automatic locking engagement, eliminating the need for tools during assembly while maintaining secure connection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The locking mechanism is designed to be self-actuating through the cam profile geometry. When the frame is moved into position relative to the pull-out element, the cam automatically engages with the locking surface, creating a secure connection without requiring external tools or complex adjustment procedures by the assembler.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If the locking mechanism is concealed in the frame profile as known from EP 1 567 032 B1, then the frame structure is compact, but unlocking becomes difficult and the locking status is not visible

Engineering Contradiction:
Improveunlocking easeVSAvoidlocking status visibility
Core Design Contradiction:
Ease of operationVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs visual indicators (such as colored markers, transparent sections, or contrasting colors) on the frame or locking components that change appearance based on the locking status. When locked, a specific visual pattern or color is visible; when unlocked, the appearance changes, providing immediate visual feedback to the user about the locking state without requiring disassembly or close inspection of hidden mechanisms.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent extracts the visibility function from the concealed locking mechanism by adding separate visual indicator elements that are coupled to the locking mechanism's state. These indicators are positioned on the exterior of the frame where they are easily visible, allowing the locking status to be detected without exposing the entire locking mechanism itself.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the latching element is spring-loaded for automatic engagement, then assembly is simplified, but the mechanism complexity increases

Engineering Contradiction:
Improveautomatic latchingVSAvoidmechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the spring-loaded latching function with the existing cam profile and frame structure. The spring is integrated into the locking assembly rather than being a separate system, and its action is coordinated with the cam's geometric profile. This merging reduces overall complexity compared to having separate latching and locking systems while maintaining automatic engagement functionality.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables tool-free assembly and secure connection of the frame to the pull-out element, with visible locking status and enhanced stability against tilting moments, while maintaining locking functionality across different height settings.

Implementation Method 1

The latching element is essentially vertically aligned and latches into a hole in the frame or the pull-out element. It is adjacent to a fastening element which dips into a keyhole-like recess with an enlarged area into which a head of the fastening element is to be inserted.

Methodology Applied
Scientific EffectSpring loading: Spring

Data Source

PatentEP2238863B1Pull-out device for cupboard pull-outs
Publication Date: 2015.09.02 KESSEBOHMER HLDG KG
  • EP2238863B1 patent drawingFigure 1~2
  • EP2238863B1 patent drawingFigure 3~4
  • EP2238863B1 patent drawingFigure 5~6

AI summary

The device has a frame (2) transferable from a locking position into a pull-out position. A latch element is assigned to a fastening element (8) for fastening the frame and/or a pull-out element (7) to a retainer (9). The latch element is held in an outer catch position during an assembly movement of the frame at the pull-out element. The latch element is automatically transferred into a locking position when reaching the assembly end position of the frame at the pull-out element, where the latch element secures the position of the fastening element in the locking position.