Dishwasher Spray Arm Gear Linkage for Wider Water Coverage

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Solution Overview

Problem

Conventional dishwashers have limited spray angles, which can lead to uneven water distribution on objects such as bowls, affecting cleaning efficiency.

Innovation Solution

The dishwasher employs a spray arm system with a main arm and auxiliary arms that rotate using a repulsive force generated by water spray, without a separate driving device, and includes a gear coupling mechanism to maintain alignment and rotation direction, ensuring even water distribution and enhanced cleaning efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a conventional spray arm structure is used, then the device complexity is low, but the spray angle is limited and water distribution is uneven

Engineering Contradiction:
Improvespray angleVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spray arm is divided into a main arm and multiple auxiliary arms that can rotate independently. Each auxiliary arm is connected to the main arm through a rotation shaft, allowing them to change the spray angle independently while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The auxiliary arms are designed to be rotatable relative to the main arm, enabling dynamic adjustment of spray angles. This dynamic structure allows the spray system to adapt to different washing needs without significantly increasing device complexity.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If a separate driving device is added to rotate auxiliary arms, then the spray angle variation is improved, but the device complexity increases

Engineering Contradiction:
Improvespray angle variationVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The auxiliary arms utilize the repulsive force generated by water spray themselves to rotate, without requiring an external driving device. The water flow creates a reaction force that naturally rotates the auxiliary arms to optimal positions, making the system self-regulating and eliminating the need for additional motors or actuators.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The rotation of auxiliary arms is driven by hydraulic pressure from the water spray. The water flow creates pressure differences that generate rotational force on the auxiliary arms, using the hydraulic system itself as the driving mechanism rather than requiring separate mechanical actuators.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Adaptability or versatility

If the auxiliary arms rotate freely, then the spray angle is optimized, but the alignment may become inconsistent

Engineering Contradiction:
Improvespray angle optimizationVSAvoidalignment consistency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system uses the water spray pattern itself as feedback to regulate the rotation of auxiliary arms. The repulsive force from the spray creates a natural equilibrium position, and any deviation from optimal alignment generates corrective forces that realign the arms, maintaining consistent positioning without requiring external control systems.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The design allows the auxiliary arms to change their rotational parameters (angle and position) in response to water flow conditions. By adjusting the spray pressure and flow rate, the system can control the rotational behavior of auxiliary arms to maintain optimal alignment under different operating conditions.

Inventive Principle:
Principle #35Parameter changes

4Strength

If the main arm rotation is coupled to auxiliary arm rotation, then the gear coupling force is reinforced, but the main arm cannot rotate when auxiliary arm rotation is blocked

Engineering Contradiction:
Improvegear coupling forceVSAvoidrotation independence
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The rotation shaft is nested within the auxiliary arm structure, with the auxiliary arm rotating around the rotation shaft while the main arm rotates around the same axis. This nested configuration allows the main arm to rotate independently while the auxiliary arms can rotate relative to it, maintaining gear coupling strength without restricting main arm rotation.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The rotational movement is segmented into two independent levels: main arm rotation and auxiliary arm rotation. The gear coupling mechanism is designed to transmit force for auxiliary arm rotation while allowing main arm rotation to proceed independently, separating the two rotational functions to avoid interference.

Inventive Principle:
Principle #1Segmentation

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 design allows for varied spray angles and improved washing efficiency by ensuring consistent water distribution across the surface of objects, even without a separate driving mechanism for the auxiliary arms, thereby enhancing the cleaning process.

Implementation Method 1

a spray arm to spray wash water to an object to be washed, a fixed gear unit, a rotary gear unit rotatably mounted on the spray arm to be engaged with gear teeth of the fixed gear unit

Methodology Applied
Scientific EffectRepulsive force: Reaction (physics)

Data Source

PatentEP3050480B1Dish washer
Publication Date: 2018.04.18 LG ELECTRONICS INC
  • EP3050480B1 patent drawingFigure 1
  • EP3050480B1 patent drawingFigure 2
  • EP3050480B1 patent drawingFigure 3

AI summary

The present invention relates to a dishwasher (1). According to an aspect, a dishwasher (1) includes a tub (2), a spray arm (100) to spray wash water to an object to be washed, a fixed gear unit (200) fixed in the tub (2), a rotary gear unit (500) rotatably mounted on the spray arm (100) to be engaged with gear teeth (213) of the fixed gear unit (200), and a link member (600) connected to the rotary gear unit (500) and the spray arm (100), wherein the spray arm (100) includes a main arm (110) including a pair of arms (113, 114), and a pair of auxiliary arms (140, 150) rotatably connected to the main arm (110), the rotary gear unit (500) rotates by being engaged with the gear teeth (213) of the fixed gear unit (200) by the rotation of the main arm (110), and the link member (600) moves by the rotation of the rotary gear unit (500) to push and rotate each of the auxiliary arms (140, 150).