Engine Choke Lever Guide Hole Layout for Compact Mounting

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Solution Overview

Problem

The existing all-purpose engines face challenges in compact design due to interference between the choke lever and connecting parts, making it difficult to mount the choke lever effectively, which affects the operability and compactness of the engine.

Innovation Solution

The design includes a guide hole with a positioning protrusion and varying sizes for the arm part, a notch on the holding part, and an elastic member to secure the arm part within the guide hole, allowing for improved mounting and reduced rattling, while maintaining compactness and operability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the choke lever is inserted from the guide hole to avoid interference with the connecting part, then the mounting becomes possible, but the holding part interferes with the air cleaner case and workability deteriorates

Engineering Contradiction:
Improvemounting property of choke leverVSAvoidworkability upon mounting
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

Instead of inserting the choke lever from the conventional side (opposite to holding part), the patent inserts it from the holding part side. This inversion of insertion direction allows the arm part to clear the connecting part while the holding part is guided by the guide hole, resolving the interference issue and improving both mounting feasibility and workability

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If the arm part is lengthened to avoid interference between holding part and air cleaner case, then mounting becomes easier, but the air cleaner case increases in overall size

Engineering Contradiction:
Improveoperability of choke leverVSAvoidoverall size of air cleaner case
Core Design Contradiction:
Ease of operationVSVolume of moving object

Solution Approach 1:

By inverting the insertion direction to insert from the holding part side, the patent eliminates the need to lengthen the arm part. The holding part itself becomes the leading element during insertion, guided by the guide hole, which allows the arm part to naturally clear the connecting part without additional length, thereby maintaining compact dimensions

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of manufacture

If the choke lever is inserted while tilting the holding part to overcome the connecting part, then mounting is possible, but the holding part interferes with the air cleaner case

Engineering Contradiction:
Improvemounting feasibilityVSAvoidease of mounting
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent inverts the insertion approach by entering from the holding part side rather than the arm part side. This allows the holding part to be guided straight through the guide hole without tilting, while the arm part naturally clears the connecting part, achieving both mounting feasibility and operational ease

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The guide hole serves as an intermediary structure that guides the holding part during insertion. By providing this guiding path, the patent enables straightforward insertion without requiring tilting maneuvers, while still allowing the arm part to clear the connecting part through the inverted insertion direction

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3730773B1All-purpose engine
Publication Date: 2022.05.04 HONDA MOTOR CO LTD
  • EP3730773B1 patent drawingFigure 1
  • EP3730773B1 patent drawingFigure 2
  • EP3730773B1 patent drawingFigure 3

AI summary

With the object of improving the mounting property of a working member for which a moving manipulation is guided by a guide hole, an opening/closing mechanism of an intake member includes: an intake member which accommodates a filter part and has an opening leading to a carburetor in an end wall opposing the filter part; an opening/closing member which is disposed between the filter part and the end wall, and opens/closes the opening; and a working member which is disposed on an opposite side to the opening/closing member so as to interpose the end wall, and allows the opening/closing member to be operated, in which the working member includes: an arm part which extends along the end wall and is linked with the opening/closing member to interpose the end wall at one end part, and a holding part provided to another end part of the arm part; the intake member has a guide hole into which the arm part is inserted and guides movement of the arm part; and the holding part is disposed to project more than the guide hole, is provided to be wider than the arm part, and has a notch part at a surface opposing the side wall of the intake member.