Driving Tool Head Valve Positioning for Height Reduction

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Solution Overview

Problem

Conventional driving tools with low entire-height structures face challenges in reducing the number of parts and cost due to the need for additional components to guide and position the head valve, which increases weight and complexity.

Innovation Solution

The head valve is positioned at the outside of the striking cylinder with the same upper and lower external diameters, allowing it to slide freely between the cylindrical inner and outer walls of the cylinder cap, eliminating the need for a special guide and simplifying the configuration, while exhaust ports at the lower portion of the cylinder cap facilitate air exhaust through a filter, reducing the number of bolts required.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the head valve is disposed at the outside of the striking cylinder to reduce the height ratio, then the entire height can be further lowered, but additional members are required for guiding and opening/closing the head valve, increasing the number of parts, weight, and cost

Engineering Contradiction:
Improveentire height of the bodyVSAvoidnumber of parts
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The cylindrical inner wall and cylindrical outer wall are merged into a single integrated structure formed on the lower surface of the cylinder cap. This combines the functions of guiding the head valve and providing structural support into one component, eliminating the need for separate guide members and reducing the total number of parts.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cylindrical inner wall and outer wall structure serves multiple functions simultaneously: it guides the head valve during movement, provides structural support for the cap, and enables the head valve to slide freely between the walls. This multi-functional design reduces the need for additional specialized components.

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

2Reliability

If additional members are disposed at the inner and outer peripheries of the head valve for guiding purposes, then the head valve can be properly guided, but the number of parts increases, resulting in increased weight and cost

Engineering Contradiction:
Improveguiding function of head valveVSAvoidweight of the body
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The guiding function is merged into the cylindrical inner wall and outer wall structure of the cap itself, rather than being provided by separate guide members. This integration eliminates additional parts while maintaining reliable guidance of the head valve during its opening and closing movements.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration reduces the number of parts, lowers the overall height of the tool, and decreases costs by simplifying the design and reducing the number of components needed, while maintaining effective operation.

Implementation Method 1

the head valve is provided so as to be slidable freely between the cylindrical inner wall and the cylindrical outer wall

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

the head valve is provided so as to be slidable freely between the cylindrical inner wall and the cylindrical outer wall

Methodology Applied
Scientific EffectNormal force: Force

Implementation Method 3

an elastic member is provided around the outer periphery of the annular projection portion and the upper end of the striking cylinder so as to urge the head valve downward

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 4

the head valve is urged so as to normally move downward (in the closing direction) by a spring

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 5

the compressed air within the main air chamber is supplied to the striking cylinder thereby to drive the striking piston and the driver, whereby a nail is struck and driven

Methodology Applied
Scientific EffectGas pressure: Pressure Increase

Implementation Method 6

the exhaust cover is disposed at the outside of the exhaust port at the side wall of the cylinder cap and exhaust gas is exhausted from an exhaust port formed at the lower portion of the exhaust cover

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP1918074B1Driving tool
Publication Date: 2011.05.11 MAX CO LTD
  • EP1918074B1 patent drawingFigure 1
  • EP1918074B1 patent drawingFigure 2
  • EP1918074B1 patent drawingFigure 3

AI summary

A striking cylinder 6 is disposed within a body 1. A main air chamber 7 for reserving compressed air therein is disposed at an outside of the striking cylinder 6. A cylinder cap 8 for covering the striking cylinder 6 and the main air chamber 7 is fixed at an upper portion of the body 1. A lower portion of a cylindrical head valve 13, which opens and closes the main air chamber 7 and the striking cylinder 6 and is configured in a manner that upper and lower external diameters thereof are the same, is disposed at an outside of the striking cylinder 6. A cylindrical inner wall 10 and a cylindrical outer wall 11 are integrally formed at a lower surface of the cylinder cap 8. A piston stop 12 for defining a top dead center of a striking piston 5 is provided at an inside of the cylindrical inner wall 10. The head valve 13 is slidably provided between the cylindrical inner wall 10 and the cylindrical outer wall 11.