Furniture Dowel-Recess Joint With Tactile End-Position Locking

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Solution Overview

Problem

Furniture assembly challenges include the need for tools, sensitivity to incorrect positioning, potential damage or injury, and weak connections that wear over time, particularly affecting the disabled, elderly, and children.

Innovation Solution

A connection arrangement using primary and secondary dowels and recesses with distinct configurations, including insertion and locking portions, and end portions to provide a clear end position and secure locking, allowing for identical design and assembly, while accommodating manufacturing variations and material changes due to moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional fastening means (screws or nails) are used to connect furniture parts, then strong connections are achieved, but tools are required and incorrect positioning may cause damage or injury

Engineering Contradiction:
Improveconnection strengthVSAvoidease of assembly
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The connection arrangement enables self-service assembly through dowels with head portions that can be pressed by hand to engage with recesses. The system requires no external tools - the furniture parts themselves provide the means for connection through the interaction between protruding dowels and corresponding recesses with locking portions.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The connection system is segmented into distinct functional elements: dowels with head portions and neck portions, and recesses with insertion portions and locking portions. This segmentation allows each component to perform its specific function independently, with the head portion providing leverage for insertion and the neck portion engaging with the locking portion for secure connection.

Inventive Principle:
Principle #1Segmentation

2Reliability

If locks are used to connect furniture parts, then connections are secured, but many parts are required and connections weaken over time due to wear

Engineering Contradiction:
Improveconnection reliabilityVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges the functions of multiple separate locking components into a single integrated recess structure. The recess combines the insertion portion and locking portion into one element that interacts with the dowel, eliminating the need for separate locks, screws, or fasteners. This reduces the total number of parts while maintaining secure connections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The recess structure serves multiple functions simultaneously: it guides the dowel during insertion through the insertion portion, secures the dowel through the locking portion, and provides a stop feature through the end portion. This multi-functionality in a single component reduces complexity while improving reliability.

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

3Manufacturing precision

If dowels and recesses are positioned precisely for exact end position, then accurate assembly is achieved, but manufacturing variations and material changes cause positioning errors

Engineering Contradiction:
Improvepositioning accuracyVSAvoidtolerance to manufacturing variations
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The invention changes the geometric parameters of the recess by adding an end portion that extends beyond the locking portion. This creates a physical stop that defines the end position independently of the precise positioning of the locking portion, allowing the system to accommodate variations in manufacturing tolerances and material expansion/contraction.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The end portion acts as a pre-positioned cushion or buffer that absorbs positioning errors and manufacturing variations. By providing this extra geometric feature beforehand, the system compensates for potential misalignments without requiring high-precision manufacturing or complex adjustment mechanisms.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

4Ease of operation

If the first furniture part is allowed to move freely along the transverse direction, then easy assembly is achieved, but the furniture parts may not reach their intended end position or may be stuck before reaching it

Engineering Contradiction:
Improveease of assemblyVSAvoidend position detection
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The end portion of the recess provides mechanical feedback to the assembler by creating a noticeable stop or resistance when the dowel reaches the intended end position. This tactile feedback confirms that assembly is complete without requiring measurement tools or complex detection systems, maintaining ease of operation while ensuring precise positioning.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3830429B1A connection arrangment and a method of providing a furniture part with recesses
Publication Date: 2023.08.30 IKEA SUPPLY AG
  • EP3830429B1 patent drawingFigure 1
  • EP3830429B1 patent drawingFigure 2A
  • EP3830429B1 patent drawingFigure 2B

AI summary

The disclosure relates to a connection arrangement for connecting a first furniture part (10) to a second furniture part (20), wherein the first furniture part (10) comprises a primary dowel (11) and a secondary dowel (12, 13 and wherein the second furniture part (20) comprises a primary recess (21) and a secondary recess (22, 23, wherein at least the primary recess (21) further comprises an end portion (21c) configured to interact with the primary dowel (11) and to provide an end position (P21) in the motion of the first furniture part (10), and wherein, the dowels (11, 12, 13) and the recesses (21, 22, 23) are positioned relative to each other such that, as the first furniture part (10) has been brought to the end position, the secondary dowel (12, 13) becomes positioned at a position (P22, P23) at which position (P22, P23) the secondary dowel (12, 13) would have been movable along the transverse direction (T) relative to the recess (22, 23) had the first furniture part (10) not been prevented from moving any further along the transverse direction (T). The disclosure also relates to method of providing a furniture part with such recesses.