Dishwasher Spray-Arm Path Control to Eliminate Corner Blind-Spots
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Solution Overview
Problem
Dishwashing machines often leave 'blind-spots' in the washing compartment, particularly at corners, where items may not be properly washed due to the spray-arm's limited rotational motion, leading to inadequate cleaning.
Innovation Solution
A dishwashing machine with a controller that varies the speed of the spray-arm's rotational motion using a look-up-table to provide both rotational and translational movement, ensuring the spray-arm reaches all corners of the compartment through a predetermined path, utilizing a transmission arrangement like a rack and pinion mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spray-arm only performs rotational motion, then the device complexity is reduced, but blind-spots are created in corner areas of the washing compartment
Solution Approach 1:
The spray-arm motion is changed from simple rotation to a dynamic path following motion that translates the spray-arm through the washing compartment. The controller varies motor speed to make the distal end of the spray-arm follow a predetermined path that covers corner areas, eliminating blind-spots while maintaining reasonable device complexity.
2Manufacturing precision
If the controller uses complex algorithms to control spray-arm speed, then cleaning precision is improved, but processing power requirements increase
Solution Approach 1:
The predetermined path and corresponding motor speeds are calculated in advance and stored in a lookup table. During operation, the controller simply retrieves pre-calculated speed values based on the current position in the path, avoiding complex real-time calculations and reducing processing power requirements while maintaining precise path control.
3Productivity
If the spray-arm moves faster to complete the washing cycle quicker, then productivity is improved, but cleaning homogeneity deteriorates
Solution Approach 1:
The spray-arm follows a predetermined path with varying speeds at different positions. The controller varies the motor speed periodically along the path, maintaining constant linear velocity of the distal end to ensure uniform cleaning coverage. This periodic speed variation allows the spray-arm to spend appropriate time in each area, maintaining cleaning homogeneity while completing the cycle efficiently.
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
Ensures thorough cleaning by ensuring all areas of the washing compartment, including corners, are reached by the spray-arm, maintaining constant linear velocity of the spray-arm's distal end and minimizing processing power, thereby enhancing cleaning efficiency and homogeneity.
Implementation Method 1
the transmission arrangement comprises a rack and pinion arrangement, the rack being located on the spray-arm
Data Source
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AI summary
There is disclosed a dishwashing machine. The dishwashing machine comprises a controller (334). The dishwashing machine further includes a spray-arm (326) having a plurality of outlets (360, 365) for spraying liquid in a washing compartment (304) of the dishwashing machine during a washing cycle. There is further provided a motor (348) for providing a rotational motion to the spray-arm (326). A transmission arrangement (374) operatively connects the motor (348) and the spray-arm (326). The transmission arrangement (374) is constructed and arranged to provide a translational movement of the spray-arm (326) in the washing compartment (304) as the spray-arm (326) rotates. The controller (334) is arranged to vary a speed of rotation of the motor (348) during the washing cycle to control movement of the spray-arm (326) according to a pre-determined path.