Dishwasher Spray Arm Bearing Mounting Without Fasteners
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Solution Overview
Problem
The existing dishwasher spray assemblies face difficulties in mounting the upper spray arm due to design constraints and tolerance issues, particularly with fasteners and snap fit connections, which can be labor-intensive and prone to errors.
Innovation Solution
A spray assembly design that includes a rotatable spray arm mounted to a bearing with projections and a flange, which is secured to a bracket with slots and channels, allowing for easy rotation and mounting to the dishwasher tub, and a method for assembling the spray assembly that facilitates secure attachment without requiring additional tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the upper spray assembly is designed with a thin or narrow profile to avoid interfering with articles, then the spray assembly can fit in limited space, but mounting the spray arm with fasteners becomes difficult
Solution Approach 1:
The spray arm assembly is segmented into modular components: the spray arm, bearing, and bracket are separate elements that can be independently manufactured and then assembled. This segmentation allows each component to be optimized for its specific function while simplifying the overall mounting process.
Solution Approach 2:
The bearing is pre-assembled with the spray arm before installation onto the bracket. This preliminary assembly ensures proper alignment and positioning, making the final mounting step simpler and more reliable while maintaining the compact profile design.
2Ease of manufacture
If snap fit connections are used to secure the spray arm, then assembly can be simpler, but a bearing must be rotated relative to the spray arm which is difficult during manufacture
Solution Approach 1:
Instead of rotating the bearing onto the spray arm during final assembly, the design inverts the approach by providing protrusions on the bearing that automatically engage with recesses in the spray arm during a single insertion motion. This eliminates the need for difficult rotational manipulation during manufacturing.
Solution Approach 2:
The bearing and spray arm are designed with complementary geometric features (protrusions and recesses) that enable self-alignment and self-assembly. When the bearing is inserted into the spray arm, the features automatically guide the components into their correct relative positions without requiring manual rotation or adjustment.
3Reliability
If fasteners such as screws are used to mount the upper spray assembly to the tub, then secure attachment is achieved, but the process is labor intensive and fasteners can strip out
Solution Approach 1:
The design extracts and eliminates the need for separate fasteners (screws, bolts, or other threading components) by incorporating integral attachment features directly into the bearing and bracket structures. The protrusions and recesses provide secure mechanical interlocking without requiring additional fastening elements, thereby reducing labor and eliminating stripping issues.
Solution Approach 2:
The attachment function is merged into the structural design of the bearing and bracket themselves. Rather than being separate fastening components, the attachment features are integrated into the load-bearing elements, providing both structural support and secure attachment in a single unified design.
4Volume of moving object
If the spray assembly uses a narrow profile design, then it avoids interfering with articles, but securing the spray arm to the blow molded conduit becomes difficult due to tolerance and geometric limitations
Solution Approach 1:
The attachment features utilize asymmetric geometric shapes with distinct male and female portions that provide directional insertion and inherent alignment. This asymmetry eliminates the need for tight tolerances by guiding the components into correct alignment through their shapes rather than relying on precision dimensional control.
Solution Approach 2:
The bearing is pre-assembled with the spray arm before installation onto the bracket, ensuring proper alignment and positioning. This preliminary assembly compensates for any variations in conduit geometry or tolerance accumulations that would otherwise make secure attachment difficult.
Data Source
AI summary
The present subject matter provides a spray assembly for a dishwasher appliance. The spray assembly includes a spray arm, a bearing, and a bracket for mounting the spray assembly to a dishwasher appliance. The spray arm is mounted for rotation relative to the bearing, and the bearing is mounted to the bracket. The spray assembly includes features for rotating the bearing relative to the bracket with the spray arm. Such rotation can assist with mounting of the bearing to the bracket.