Impact Tool Discharge Passage Prevents Idle Impact

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Solution Overview

Problem

In impact tools, the accumulation of air and grease between the cylinder and intermediate element due to temperature rise and operation can inhibit the descending operation of the intermediate element, leading to clearance formation and idle impact issues when the tool bit is separated from a machining object.

Innovation Solution

The impact tool incorporates passages and a labyrinthine structure to discharge foreign objects, such as grease and air, outside the cylinder, preventing movement inhibition and idle impacts by ensuring proper contact between the tool bit and intermediate element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grease is enclosed in the casing to lubricate moving parts, then lubrication effectiveness is improved, but foreign objects accumulate between the cylinder and intermediate element causing movement inhibition

Engineering Contradiction:
Improvelubrication effectivenessVSAvoidforeign object accumulation
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent divides the internal space into two separate chambers: a storage chamber containing grease and a working space between the cylinder and intermediate element. A partition wall with a discharge passage separates these spaces, allowing grease to be stored while preventing excessive accumulation in the working space. This segmentation resolves the contradiction by maintaining lubrication effectiveness while preventing foreign object accumulation that causes movement inhibition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The partition wall acts as an intermediary structure between the grease storage chamber and the working space. It includes a discharge passage that mediates the flow of grease, allowing controlled lubrication while preventing uncontrolled accumulation. This intermediary structure resolves the contradiction by enabling grease to perform its lubrication function without causing harmful accumulation effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If the piston operates reciprocally to generate impact force, then impact function is improved, but air enters between the cylinder and intermediate element causing clearance formation

Engineering Contradiction:
Improveimpact forceVSAvoidair accumulation
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The patent extracts air and other foreign objects from the working space through the discharge passage in the partition wall. The passage allows air to be discharged from the space between the cylinder and intermediate element, preventing clearance formation while maintaining the reciprocating piston operation for impact force generation. This resolves the contradiction by removing the harmful air accumulation while preserving the beneficial impact function.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If the tool bit is separated from the machining object, then operation flexibility is improved, but idle impact occurs due to clearance between tool bit and intermediate element

Engineering Contradiction:
Improveoperation flexibilityVSAvoididle impact
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The discharge passage in the partition wall provides self-service by automatically discharging air and foreign objects from the working space during normal operation. This prevents clearance formation between the tool bit and intermediate element, eliminating idle impact while maintaining operation flexibility. The system self-regulates to prevent the harmful effect without requiring additional control mechanisms.

Inventive Principle:
Principle #25Self-service

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 effectively prevents idle impacts by ensuring the intermediate element can move freely, maintaining effective force transmission and reducing the risk of clearance formation between the tool bit and intermediate element.

Implementation Method 1

The impact tool incorporates passages and a labyrinthine structure to discharge foreign objects, such as grease and air, outside the cylinder

Methodology Applied
Scientific EffectLabyrinthine structure:

Implementation Method 2

when the tool bit which is directed downward is separated from a machining object, the tool bit descends in the inside of the cylinder due to the own weight

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP2978569B1Impact tool
Publication Date: 2024.08.21 KOKI HLDG CO LTD
  • EP2978569B1 patent drawingFigure 1
  • EP2978569B1 patent drawingFigure 2
  • EP2978569B1 patent drawingFigure 3

AI summary

An impact tool capable of preventing an impact force from being applied to an intermediate element in a state where the intermediate element and a tool bit are apart from each other is provided. An impact tool 10 which transmits an impact force to a tool bit 12 supported by a casing 13 includes: a cylinder 31 which is attached to the casing 13 and has an opening on one end side thereof to which the tool bit 12 is inserted; an intermediate element 57 which is provided in an inside of the cylinder 31 so as to be able to move straight, has a projection 58 projecting in a radial direction so as to regulate a range of the straight movement, and transmits the impact force to the tool bit 12; and passages 69 and 70 which communicate a space D in an inside of the cylinder 31 at a position nearer to the tool bit 12 than the projection 58 with the outside of the cylinder 31 and penetrate through the cylinder 31 in the radial direction.