Offset-Rotation Spray Arm Assembly for Dishwasher Corner Coverage
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Solution Overview
Problem
Current dishwasher spray arm assemblies with circular geometry fail to effectively reach the corners of square or rectangular dishwasher interiors, leading to inadequate cleaning and increased stress due to reactionary forces from the spray arm components and liquid flow.
Innovation Solution
A spray arm assembly with a plurality of branches connected about a center point, featuring a base conduit and intermediate conduit system that allows for offset rotation, facilitating efficient wash fluid distribution to the periphery and corners through a Reuleaux triangle path, and incorporating a gear assembly with hollow and solid bearings to minimize stress and binding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circular spray arm assembly is used, then the structure is simple and easy to manufacture, but the corners of the square or rectangular dishwasher interior are not sufficiently reached by wash fluid
Solution Approach 1:
The spray arm assembly transitions from a circular to an asymmetric design where the spray arm rotates in an elliptical path with a larger dimension extending toward the rear wall of the dishwasher. This asymmetric geometry enables the spray arm to reach the corners of the square or rectangular dishwasher interior that would be inaccessible with a circular rotation path, thereby improving wash fluid coverage effectiveness while maintaining manufacturing simplicity.
2Productivity
If jets are angled towards the outer periphery to direct wash fluid towards corners, then corner coverage is improved, but the design becomes complex and expensive
Solution Approach 1:
Instead of using complex fixed angled jets or pivoting supports, the invention employs a dynamic solution where the entire spray arm assembly rotates in an elliptical path. This dynamic rotation allows the spray arm to naturally direct wash fluid toward the corners at appropriate moments in its rotation cycle, achieving corner coverage without requiring complex angled jet configurations or additional mechanical components.
3Productivity
If pivoting supports or outer peripheral tracks are used to guide spray arm assemblies, then corner coverage is improved, but the design becomes complex, expensive, and ineffective
Solution Approach 1:
The invention extracts and eliminates the complex pivoting supports and outer peripheral tracks from the design. Instead of adding these complex guidance mechanisms, the spray arm assembly is designed to rotate directly in an elliptical path through its mounting configuration and geometry, achieving corner coverage without the need for additional complex guidance infrastructure.
4Ease of manufacture
If cantilevered spray arm component designs are used, then installation is simplified, but the components are subject to considerable stresses from reactionary forces
Solution Approach 1:
The invention addresses the stress issue by designing a balanced elliptical rotation system where the spray arm assembly is counterbalanced to offset the reactionary forces generated during rotation. This counterbalancing mechanism reduces the net stresses on the cantilevered components, allowing them to withstand the rotational forces without excessive wear or failure, thereby maintaining installation simplicity while improving durability.
Data Source
AI summary
A spray arm assembly includes a spray arm including a plurality of branches connected to each other and arrayed about a center point, each of the plurality of branches defining a passage therethrough and an aperture in fluid communication with the passage. The center point defines a spray arm central axis. The spray arm is rotatable about the spray arm central axis. The spray arm assembly further includes a base conduit defining a passage therethrough, the base conduit defining a base conduit central axis. The base conduit central axis is offset from the spray arm central axis. The spray arm assembly further includes an intermediate conduit connecting the base conduit and the spray arm, the intermediate conduit defining a passage in fluid communication between the passage of the base conduit and the passages of the plurality of branches. The intermediate conduit is rotatable about the base conduit central axis.