Stair Step Connection Sleeve for Hidden, Stable Assembly

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Solution Overview

Problem

Existing connecting devices for staircases and furniture components face issues such as weakened stability, aesthetically undesirable designs, cumbersome assembly, and difficulty in replacing or disassembling parts, particularly due to exposed load-bearing elements and complex mounting mechanisms.

Innovation Solution

A connecting device featuring a supporting element and a holding element with exposed areas that can be covered by a sliding sleeve, allowing for easy assembly and disassembly while maintaining aesthetic appeal and safety, with secure fastening mechanisms to prevent accidental opening or loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mounting slot is created in the step for inserting a cylindrical pin to turn the rotatable threaded bush, then the threaded bush can be turned during assembly, but the stability of the stair step is weakened in the area of the fastening sockets

Engineering Contradiction:
Improveturning the threaded bush during assemblyVSAvoidstability of the stair step
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The invention extracts the turning function from the mounting slot concept and implements it through a hexagonal outer contour of the threaded bush that engages with a hexagonal socket in the stringer. This allows turning during assembly without creating slots in the step, thus maintaining step stability while enabling operational access.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The hexagonal interface serves multiple functions: it provides the turning mechanism during assembly, acts as a locking feature to prevent rotation during service, and eliminates the need for separate mounting slots. This multi-functionality resolves the contradiction between ease of operation and structural stability.

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

2Ease of operation

If a mounting slot is created on the underside of the step to access the rotatable threaded bush, then the bush can be turned during assembly, but the mounting slot is aesthetically undesirable even when covered

Engineering Contradiction:
Improveaccess to threaded bush for turningVSAvoidaesthetic appearance of the step underside
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The invention removes the mounting slot entirely from the step structure and relocates the turning access function to the stringer side through the hexagonal socket. This eliminates the aesthetic defect on the step underside while preserving the operational capability through the hexagonal engagement feature.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If the rotatable threaded bush is turned during assembly to connect the step and stringer, then a high load-bearing connection is achieved, but the assembly process is difficult because the step must be kept still and perpendicular while turning

Engineering Contradiction:
Improveload-bearing capacity of the connectionVSAvoidassembly process
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

Instead of turning the threaded bush during final assembly under constraint, the invention inverts the approach by pre-assembling the threaded bush with the step in a relaxed state, then securing it to the stringer. This reverses the difficulty from the assembly operation to a simpler fastening operation, maintaining high load-bearing capacity while greatly easing the assembly process.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of operation

If the mounting slot is positioned on the underside of the step, then the cylindrical pin can access the rotatable threaded bush, but the pin is difficult to thread in and can easily fall out during mounting

Engineering Contradiction:
Improveaccess to threaded bushVSAvoidhandling of the cylindrical pin
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the pin-and-slot mechanism entirely and replaces it with a hexagonal socket interface integrated into the stringer. This eliminates the handling difficulties of separate pins while providing secure engagement through the hexagonal geometry that prevents both insertion and removal issues.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2085533B1Connection device for connecting step and side wall on a staircase or furniture parts
Publication Date: 2016.03.30 SEIDL WALTER
  • EP2085533B1 patent drawingFigure 1~2
  • EP2085533B1 patent drawingFigure 3a~4
  • EP2085533B1 patent drawingFigure 5a~6

AI summary

The device (1) has a support element (4) fixed to a side wall (2), and a retaining element (5) fixed to a step (3). The elements are fixedly connected with each other for connecting the step with the side wall. The support element has a support area (10), and the retaining element has a contact area (16) that is connected to the support area. The support and contact areas freely rest between the step and the side wall in an installed condition of the device and are covered by a covering element e.g. tubular sleeve (6), which is shiftably arranged at the retaining element.