Window Fitting Driver Segmentation for Wear Reduction
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Solution Overview
Problem
Existing window and door fittings experience high frictional forces between plastic stop bodies and metal drivers, leading to increased wear and reduced long-term load capacity, affecting reliability and durability.
Innovation Solution
Designing the first part of the driver from Zamak alloy and the second part from plastic, allowing for improved sliding properties and reduced friction, with the second part serving as a sliding element within the stop body, and connecting both parts in a rotationally fixed manner to form a solid unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the stop body is made of plastic and the drive pin is made of metal (Zamak alloy), then the fitting can be manufactured cost-effectively with good structural properties, but high frictional forces occur between the stop body and drive pin leading to increased wear and reduced durability
Solution Approach 1:
The drive pin is divided into two separate parts: a metal first part (axle) providing structural strength and a plastic second part (sliding element) providing low-friction sliding surfaces. This segmentation allows each part to be optimized for its specific function, resolving the contradiction between manufacturing cost and durability.
Solution Approach 2:
The drive pin combines metal and plastic materials in a single component. The metal first part provides mechanical strength while the plastic second part provides low-friction sliding properties. This composite approach eliminates the wear problems of metal-on-plastic interfaces while maintaining cost-effectiveness.
2Strength
If a metal drive pin is used in the stop body, then the fitting has sufficient mechanical strength, but frictional forces negatively impact long-term durability and increase wear on the stop body and detent elements
Solution Approach 1:
The drive pin is segmented into a metal first part for structural strength and a plastic second part for low-friction sliding. This allows the fitting to maintain mechanical strength while significantly reducing wear on the stop body and detent elements.
Solution Approach 2:
The plastic second part acts as an intermediary sliding element between the metal first part and the plastic stop body. This intermediary layer reduces direct metal-to-plastic contact and friction, thereby improving long-term durability while maintaining structural integrity.
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
This design significantly reduces wear, enhances the locking mechanism's reliability, and increases the fitting's long-term load capacity while maintaining cost-effectiveness and ease of assembly.
Implementation Method 1
The detent balls lie in the same plane as the locking elements and are radially biased outwards by a compression spring
Implementation Method 2
This results in relatively high frictional forces between the stop body and the drive pin, particularly in the flange area, which negatively impacts the fitting's long-term durability
Data Source
Figure 1
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AI summary
A window or door fitting (1) for operating a mechanism integrated in a window or door has a stop body (4) that can be attached to the window or door, a handle (6) that is axially fixed and rotatable on the stop body (4), a polygon (8) for mechanically coupling the fitting (1) to the mechanism integrated in the window or door, and a coupling arrangement (10) formed between the handle (6) and the polygon (8), by which torque transmission from the handle (6) to the polygon (8) can be effected, while from the polygon (8) to the handle (6) it can be locked. For this purpose, the coupling arrangement (10) has two drivers (28, 42), wherein a first driver (28) is rotationally fixed to the handle (6), while a second driver (42) receives the polygon (8) rotationally fixed.The stop body (4) also incorporates locking means (34) with which the first driver (28) can be locked in at least one preferred operating position of the handle (6) and/or the mechanism integrated in the window or door. To increase the durability of the fitting 1 and to meet further requirements for the fitting 1, the first driver (28) is designed in two parts, wherein a first part (281) is axially and rotationally fixed to the handle (6), and wherein a second part (282) is provided with locking recesses (134) for the locking means (34).