Divided Tool Guide for Motor Hammer Lateral Force Protection

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Solution Overview

Problem

Motor-operated hammers with pneumatic striking mechanisms face durability issues due to high loads and lateral forces, particularly when using tools with non-symmetrical contours, which can lead to structural damage and reduced lifespan.

Innovation Solution

A guide device with a divided tool guide, comprising an upper guide part for axial mobility and impact absorption, and a lower guide part for rotational prevention and damping, integrated within a one-piece guide cylinder, utilizing materials like aluminum and hardened steel or high-strength plastics to distribute and absorb forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single-piece tool guide is used, then the structure is simple and manufacturing is easy, but the guide cylinder is vulnerable to damage from lateral forces and has reduced durability

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoiddurability under lateral forces
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The tool guide is divided into two separate parts: an upper tool guide and a lower tool guide. The upper tool guide absorbs axial impacts and can move axially relative to the lower tool guide, while the lower tool guide is fixed to the guide cylinder and prevents tool rotation. This segmentation allows each part to specialize in specific functions, improving overall durability without complicating manufacturing.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs different materials for different components: the guide cylinder is made of aluminum (lightweight), while the tool guides are made of hardened steel or high-strength plastics (durable). This composite material approach optimizes the overall structure by using lightweight materials where possible and high-strength materials where durability is critical, resolving the contradiction between manufacturing simplicity and reliability.

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the tool guide is fixed rigidly, then rotational prevention is effective, but axial impacts are transmitted directly to the guide cylinder causing structural damage

Engineering Contradiction:
Improverotational stabilityVSAvoidresistance to axial impacts
Core Design Contradiction:
Stability of the object's compositionVSStrength

Solution Approach 1:

The tool guide is segmented into upper and lower parts with distinct functions. The lower tool guide is rigidly fixed to prevent rotation, while the upper tool guide is designed to move axially to absorb impacts. This functional segmentation allows the system to simultaneously achieve rotational stability and impact resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The upper tool guide acts as a cushioning element that absorbs axial impacts before they reach the guide cylinder. By providing this preliminary cushioning, the system protects the guide cylinder from structural damage while the lower tool guide maintains rotational stability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If a flanged connection is used to attach the tool holder, then the connection is robust, but additional components and machined surfaces increase costs

Engineering Contradiction:
Improveconnection robustnessVSAvoidnumber of components
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the tool guide function with the tool holder function into a single integrated component. The tool guide is inserted into the tool holder recess and secured with simple axial retention elements, eliminating the need for separate flanged connections. This merging reduces the number of components and simplifies manufacturing while maintaining connection robustness through the integrated design.

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

The solution provides a lightweight, cost-effective motor-operated hammer with enhanced fatigue strength and protection for the guide cylinder, effectively absorbing axial and lateral impacts while preventing tool rotation, thus extending the hammer's operational lifespan and reducing damage from transverse forces.

Implementation Method 1

An air spring is positioned between the drive piston and the percussion piston, which delays the smoothly oscillating movement of the drive piston and transfers it to the percussion piston, allowing it to accelerate significantly.

Methodology Applied
Scientific EffectAir spring: Spring

Implementation Method 2

A plastic sleeve is inserted between the tool guide and the guide cylinder, serving as a spring device. The plastic sleeve absorbs axial impacts introduced via the tool guide against the guide cylinder, thus protecting the guide cylinder from high loads.

Methodology Applied
Scientific EffectImpact absorption: Damping

Implementation Method 3

The lower guide part can be made of plastic to ensure that lateral vibrations and shocks occurring in this area are only transmitted to the guide cylinder in a dampened manner and to serve as an elastic mount for the upper guide part.

Methodology Applied
Scientific EffectElastic mounting: Elasticity

Data Source

PatentEP4403310A1Motor driven hammer with pneumatic striking mechanism and guiding device therefor
Publication Date: 2024.07.24 WACKER NEUSON PRODUKTION GMBH & CO KG
  • EP4403310A1 patent drawingFigure 1~2
  • EP4403310A1 patent drawingFigure 3
  • EP4403310A1 patent drawingFigure 4

AI summary

A guide device for a motor-driven hammer with a pneumatic impact mechanism is described, comprising a guide cylinder (1), a piston recess (7) for guiding a piston (4), and a tool guide (2) for receiving a tool end. A tool guide recess (8) is formed in the guide cylinder (1), axially offset from the piston recess (7), and the tool guide (2) is inserted into this recess. The guide cylinder (1) is designed as a single-piece metal body into which the tool guide (2), also designed as a single-piece metal body, is inserted. With respect to an upright position of the guide device, the tool guide (2) has an upper guide section (41) and, separate from the upper guide section (41), a lower guide section (42) arranged axially offset from the upper guide section (41).