Composite Washing Machine Drum Hatch for Low-Swarf Manufacturing
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Solution Overview
Problem
The manufacturing of access hatches for top-loading washing machines is inefficient due to high swarf generation and the need for specialized equipment to produce different sizes, leading to increased costs and unpleasant user interactions with metal edges.
Innovation Solution
A composite access hatch design where a metal frame with separate hooking and hinge portions is overmoulded with plastic, allowing for reduced swarf and versatility in size variations, with the connection points being concealed by the plastic for user safety and aesthetics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single-piece metal frame is used to make the leaf, then the leaf structure is simple and strong, but the amount of swarf generated during manufacturing is large and specialized equipment is required for each size
Solution Approach 1:
The metal frame is divided into separate components (hooking portion and hinge portion) that are manufactured independently and then assembled. This segmentation reduces swarf generation during manufacturing while maintaining the structural integrity of the complete frame assembly.
Solution Approach 2:
The patent combines metal frame components with plastic material through overmoulding to create a composite leaf structure. This composite approach reduces the need for extensive metal machining, thereby reducing swarf generation while maintaining strength.
2Ease of manufacture
If a single-piece metal frame with complex shape is manufactured, then the leaf can be made in one piece, but specialized presses and shearing machines are required for each size variation
Solution Approach 1:
By segmenting the frame into standardized components that can be assembled in different configurations, the patent enables easy adaptation to various hatch sizes without requiring specialized equipment for each size.
Solution Approach 2:
The separate hooking and hinge portions can be designed as universal components that can be combined in different arrangements to create leaves for various hatch sizes, making the manufacturing process versatile and adaptable.
3Strength
If metal leaves are used, then the structure is strong and durable, but the manual contact with metal edges is unpleasant and jagged
Solution Approach 1:
The patent creates a composite leaf by overmoulding plastic material onto the metal frame components. This composite structure retains the strength and durability of the metal frame while providing a smooth, pleasant plastic surface for user contact, eliminating the harmful effect of jagged metal edges.
Solution Approach 2:
The plastic material is applied specifically to the portions of the leaf that contact the user's hands, while the metal frame remains exposed in structural areas where strength is needed. This local differentiation of material properties solves both the strength and user comfort requirements.
Data Source
Figure 1~3
Figure 4~6
Figure 7~9
AI summary
A drum (1) for a washing machine (3, 4) comprises a metal frame (5) that forms a hooking portion (6) to lock the leaf (3, 4) in a closed position and a hinge portion (7) for the rotary connection of the leaf to the drum (1) and a body made of plastic material (8) injection moulded onto the metal frame (5), forming a composite leaf with an outer surface (9) made of plastic material, wherein the hooking portion (6) and the hinge portion (7) are separately manufactured pieces and then are connected together before the formation of the plastic body (8) on the frame (5).