Washing Machine Door Assembly Using Heat-Formed Fasteners
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Solution Overview
Problem
Front-loading washing machine doors require lengthy assembly times and high investment due to the use of numerous screws for bonding the door frame and cover, which also increases material costs, and existing alternatives like welding require same-material components and higher-quality plastics for aesthetic parts.
Innovation Solution
The door frame and cover are bonded using heat-deformed fastening elements made integrally with the frame cover, allowing different material combinations and reduced material costs, with the bonding elements being widened to form a form-fit connection and optionally reinforced with screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screws are used to bond the door frame and cover, then the connection strength is sufficient, but the assembly time increases and material costs increase
Solution Approach 1:
The patent removes screws entirely from the bonding process. Instead, bonding elements are made integrally as a single piece with the frame cover, eliminating the need for separate fastening components and reducing assembly steps while maintaining connection strength through form-fit connections and optional adhesive bonding.
Solution Approach 2:
The bonding elements are merged with the frame cover as a single integral component. This integration reduces the number of parts and assembly operations required, directly addressing the assembly time issue while maintaining sufficient connection strength through the combined mechanical and adhesive bonding mechanisms.
2Productivity
If welding is used to bond the door frame and cover, then the assembly cycle time is reduced and material costs are reduced, but both pieces must be made of the same material and the frame cover requires higher-quality plastic
Solution Approach 1:
The bonding elements serve multiple functions: they provide mechanical form-fit connection, serve as anchors for adhesive bonding, and can be made from different materials than the frame or cover. This multi-functionality allows the use of diverse material combinations while maintaining assembly efficiency and connection strength without requiring identical materials.
Solution Approach 2:
The patent enables the use of different materials for the door frame and cover by introducing bonding elements that can be made from materials suitable for bonding to both components. This composite approach allows optimization of each component's material properties for its specific function while maintaining strong bonds between dissimilar materials.
3Reliability
If multiple screws are used to fasten the door assembly, then the connection reliability is high, but the number of parts and manufacturing complexity increase
Solution Approach 1:
The bonding function is segmented into multiple bonding elements distributed around the perimeter of the frame cover. This segmentation provides reliable connection through multiple attachment points while reducing the complexity associated with traditional screw fastening systems, as each bonding element is integrally formed with the cover.
Solution Approach 2:
The bonding elements are self-contained features of the frame cover that provide their own fastening function without requiring separate screws or additional fastening components. This self-service approach maintains connection reliability while significantly reducing the total number of parts and manufacturing complexity.
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 method significantly reduces assembly cycle time and material costs by eliminating screws, enabling the use of different materials for the door frame and cover, while maintaining aesthetic quality with reduced investment in tools.
Implementation Method 1
an end of each bonding element protruding from a hole in the door frame opposite the frame cover is widened by heat deformation towards the hole edge forming a head
Implementation Method 2
a hollow pin, particularly with a cylindrical aperture into which a tool is inserted that melts and pushes the material outwardly, shaping it conformally over the outer wall of the door frame
Data Source
Figure 1~2b
Figure 3
AI summary
Front-loading washing machine door that includes an annular door frame (2), a plastic frame cover (4) covering the door frame, and a circular window component (3) with an edge (31) held between the door frame and the frame cover, wherein the door frame and the cover are bound by means of fastening elements (5). The fastening element (5) has a bonding element (6) that is made/bonded integrally as a single piece with the frame cover (4), and one end of the bonding element 6, which protrudes through an aperture (7) in the door frame (2) opposite the frame cover (4), is widened toward the aperture edge (71), forming a head 8 fastening the door frame by a form-fitted connection.