Pneumatic Percussion Control for Reliable Mode Transition

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Solution Overview

Problem

Existing impact mechanisms in drills and percussion hammers face challenges in reliably transitioning from idle to percussion modes, with inefficiencies and unreliability in starting percussion operations due to ambiguous amplitude frequency responses and environmental conditions.

Innovation Solution

A non-linear oscillatable percussion unit with a control unit that sets operating parameters to a starting value within an unambiguous amplitude frequency range, utilizing sensors and filters to detect mode changes and environmental conditions, and a learning mode to optimize operating parameters for reliable percussion initiation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the operating parameter is set to a supercritical operating value for percussion operation, then the percussion performance is improved, but the transition from idle to percussion mode becomes unreliable due to ambiguous amplitude frequency response

Engineering Contradiction:
Improvepercussion performanceVSAvoidtransition reliability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The control unit temporarily sets the operating parameter to a starting value before the ambiguous range, ensuring the system is in a stable state before transitioning to the supercritical operating value. This preliminary action at a safe operating point guarantees reliable mode transition while maintaining the ability to achieve high percussion performance afterward.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts the operating parameter in stages: first to a starting value for reliable transition, then to the supercritical working value for optimal performance. This dynamic, two-stage parameter adjustment resolves the contradiction between reliable transition and high performance.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the operating parameter is set to a starting value below the supercritical value for reliable mode transition, then the transition reliability is improved, but the percussion performance is reduced

Engineering Contradiction:
Improvetransition reliabilityVSAvoidpercussion performance
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The starting value serves as a preliminary operating point that ensures reliable transition from idle to percussion mode. After successful transition, the system then adjusts to the optimal supercritical working value, so the temporary reduction in performance is only during the transition phase, not during actual operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The parameter adjustment occurs in periodic stages: first setting to starting value for transition, then switching to supercritical working value for performance. This staged, periodic parameter adjustment allows the system to achieve both reliable transition and high performance at different times in the operation cycle.

Inventive Principle:
Principle #19Periodic action

3Speed

If the operating parameter changes rapidly from idle to percussion mode, then the response time is improved, but the system stability deteriorates due to ambiguous amplitude frequency response

Engineering Contradiction:
Improveresponse timeVSAvoidsystem stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The control unit performs a preliminary parameter setting to a starting value before the ambiguous range, creating a stable intermediate state. This preliminary action prevents direct rapid transitions through the unstable ambiguous range, maintaining system stability while still achieving relatively fast response.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system skips over the ambiguous unstable range by using a starting value as an intermediate step. Instead of directly jumping from idle to supercritical values (which would cause instability), the system rushes through the safe starting value first, then transitions to the target working value, avoiding the unstable region.

Inventive Principle:
Principle #21Skipping (Rushing through)

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

Ensures reliable and efficient transition to percussion mode by setting optimal operating parameters, reducing noise and vibrations, and adapting to varying environmental conditions, thereby enhancing the performance and reliability of the impact mechanism.

Implementation Method 1

the starting value lies in a range of the percussion mechanism speed at which an amplitude frequency response of a vibrating body of the percussion mechanism has an unambiguous solution

Methodology Applied
Scientific EffectAmplitude frequency response: Resonance

Implementation Method 2

A relationship between an operating parameter and the impact amplitude of a striker or another component of the impact mechanism used to generate impacts can, in particular, exhibit hysteresis

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Data Source

PatentEP2855095B1Percussion unit
Publication Date: 2025.07.09 ROBERT BOSCH GMBH
  • EP2855095B1 patent drawingFigure 1
  • EP2855095B1 patent drawingFigure 2
  • EP2855095B1 patent drawingFigure 3~4

AI summary

Percussion unit, especially for a rotary hammer and/or percussion hammer (12a-d), comprising a control unit (14a-d) which is designed for open-loop and/or closed loop control of a pneumatic percussion mechanism (16a-d). According to the invention, the control unit (14a-d) is designed to adjust, in at least one operating state in which it changes from an idle mode to a percussion mode, at least one operating parameter (18a-c) temporarily to a starting value (20a).