Bell Mouth Rotational Coupling for Screw-Free AC Fixation

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Solution Overview

Problem

Conventional air conditioner indoor units require numerous screws for fixing the bell mouth to the drain pan, leading to increased costs and cumbersome detachment processes, which complicates maintenance work.

Innovation Solution

The indoor unit incorporates coupling fittings with protruded heads on the drain pan's inner circumferential wall and corresponding through-holes and engaging holes on the bell mouth's outer circumferential part, allowing the bell mouth to be fixed and detached by rotating it within the bell-mouth mounting hole, reducing the number of components and simplifying the attachment/detachment process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple screws are used to fix the bell mouth to the drain pan, then the fixation reliability is improved, but the number of components and cost increase

Engineering Contradiction:
Improvefixation reliabilityVSAvoidnumber of screws
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The fixing mechanism is segmented into multiple discrete coupling fittings distributed around the bell-mouth mounting hole, with each fitting containing a head, shank, and engaging structure. This segmentation allows the bell mouth to be fixed at multiple points without requiring multiple separate screws, reducing component complexity while maintaining reliable fixation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The coupling fitting integrates multiple functions into a single component: the shank provides structural connection, the head enables rotational engagement, and the integrating mechanism combines fixing and detaching operations. By merging these functions into one component rather than using separate screws and retaining features, the patent reduces the total number of components needed.

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If multiple screws are used to fix the bell mouth, then the fixation strength is improved, but the workability and ease of detachment deteriorate

Engineering Contradiction:
Improvefixation strengthVSAvoidease of detachment
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The coupling fitting employs a dynamic fixing mechanism where the head of the coupling fitting rotates relative to the bell mouth during attachment and detachment. The head engages with the bell mouth in a rotated state to provide strong fixation, and can be easily detached by rotating back to the initial state. This dynamic mechanism allows strong fixation during operation while enabling easy maintenance access.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling fitting is pre-installed on the drain pan before the bell mouth is attached. The head of the coupling fitting is positioned in advance to engage with the bell mouth through simple rotation, eliminating the need for workers to manually loosen multiple screws during maintenance. This preliminary positioning of the coupling fitting head enables quick and easy detachment.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If multiple screws are used for fixation, then the structural stability is improved, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvestructural stabilityVSAvoiddevice complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The coupling fitting serves multiple functions: it provides structural connection between the drain pan and bell mouth, enables rotational engagement for secure fixation, and allows easy detachment through reverse rotation. This multi-functional design replaces multiple specialized components (screws, retaining rings, etc.) with a single universal coupling fitting, reducing device complexity while maintaining structural stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The coupling fitting utilizes rotational movement in the angular dimension to achieve both secure fixation and easy detachment. Instead of requiring linear insertion and removal of multiple screws, the head rotates around the shank axis to engage and disengage from the bell mouth. This dimensional change from linear to rotational operation simplifies the overall device structure while maintaining stable fixation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3598020B1Indoor unit for air conditioner
Publication Date: 2021.12.22 TOSHIBA CARRIER CORP
  • EP3598020B1 patent drawingFigure 1
  • EP3598020B1 patent drawingFigure 2
  • EP3598020B1 patent drawingFigure 3

AI summary

An air conditioner includes a drain pan possessing an inner circumferential wall defining a bell-mouth mounting hole and a bell mouth. The coupling fittings are provided in the inner circumferential wall. The coupling fittings include a head at a lower end of a shank, the head possessing a diameter greater than the shank. The fixing parts are provided in the bell mouth. The fixing part includes a through-hole and an engaging hole continuous with the through-hole. In a state where the head is made to penetrate the through-hole, when the bell mouth is rotated, the head moves from the through-hole to the engaging hole to get caught on the engaging hole, and the bell mouth is fixed to the drain pan.