Tapered Connector Butt Joint for Wooden Window Frames
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Solution Overview
Problem
Existing butt joint arrangements for window and door frames, particularly in wooden constructions, face challenges such as increased manufacturing effort and damage to pre-painted lacquer layers due to high friction and force application during assembly, leading to suboptimal wood protection and longevity.
Innovation Solution
A butt joint arrangement featuring a connector element that tapers in the insertion direction, minimizing the required application of force and friction, allowing for a form-fitting or force-fitting connection without undercuts, which simplifies assembly and maintains the integrity of the paint layer, and can be integrated or provided as a separate part with a center tapering design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-painted parts are used for assembly, then manufacturing effort is reduced and paint seal is complete, but the existing lacquer layer in the joining area is damaged due to friction and force application
Solution Approach 1:
The connector element changes its geometric parameters along its length by incorporating a tapered section with gradually decreasing cross-sectional area. This parameter change reduces the insertion force and friction during assembly, preventing damage to the pre-applied lacquer layer while maintaining a complete paint seal.
Solution Approach 2:
Instead of applying force to push a uniform connector through the joining area (which damages the lacquer), the design inverts the approach by using a tapered connector that naturally guides itself into position with minimal force. The larger end enters first and gradually transitions to the smaller end, reversing the typical force application methodology.
2Strength
If pins are pressed into recesses to create a secure connection, then a strong joint is formed, but severe friction occurs and the paint layer is broken up or sheared off
Solution Approach 1:
The connector element incorporates a tapered section where the cross-sectional area gradually decreases along the insertion direction. This parameter change allows the connector to be inserted with minimal friction and force, preventing paint layer damage while still achieving a secure joint through the tapered fit.
Solution Approach 2:
The tapered section of the connector element introduces a curved, non-uniform geometry that facilitates smooth insertion. This curved transition from larger to smaller cross-section reduces stress concentration and friction compared to a uniform cylindrical pin, protecting the paint layer during assembly.
3Reliability
If tenons are pressed into slots over a long distance, then a secure connection is achieved, but severe friction causes damage to the paint layer on pre-painted parts
Solution Approach 1:
The connector element features a tapered section with gradually changing cross-sectional dimensions along the insertion path. This parameter change reduces the insertion distance and friction force required to achieve a secure connection, protecting the paint layer from damage while maintaining connection reliability.
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
The present invention relates to a butt joint arrangement for window/door frames or window/door sash frames, in particular for wooden windows/doors, comprising: a first frame profile element, which has a first joining section arranged at one end of the frame profile element; and a second frame profile element, which has a second joining section with a insertion recess; wherein the second joining section is designed to be form-fit and/or force-fit to the first joining section by means of a plug-in connection element, and wherein the plug-in connection element and/or the insertion recess has a tapered design in the insertion direction.The present invention further relates to a window/door frame or window/door sash frame, in particular for wooden windows/doors, with such a butt joint arrangement, and to a frame profile element for window/door frames or window/door sash frames, for such a window/door frame or window/door sash frame.