Geneva Gear Electromechanical Gear Selection for Drilling Speed Control

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Solution Overview

Problem

Core drilling machines face challenges in precisely matching the rotational speed and torque of drill bits to varying drill bit diameters and material hardness, leading to inefficient processes or tool damage due to lack of fine-tuning capabilities in existing systems.

Innovation Solution

A method for setting gears in a machine tool transmission, specifically a core drilling machine, using an electric motor, control device, operating device with signal transmitters and sensors, shift fork, and Geneva gear to adjust speed and gear selection, allowing for electronic and mechanical gear changes to maintain constant peripheral speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a gearbox with multiple gears is used to adjust rotational speed and torque, then the adaptability to different drill bit diameters and material hardness is improved, but the device complexity increases

Engineering Contradiction:
Improveadaptability to different drill bit diameters and material hardnessVSAvoidgearbox complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical fine-tuning mechanisms with an electronic control system. The control device electronically adjusts the rotational speed of the electric motor based on signals from sensors that detect drill bit diameter and material properties, eliminating the need for complex mechanical adjustment mechanisms while maintaining adaptability across different drilling conditions

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system transitions from static gear selection to dynamic electronic control. The control device continuously adjusts the motor speed in real-time based on feedback from sensors, allowing the system to dynamically adapt to varying drill bit diameters and material hardness without requiring complex mechanical reconfiguration

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If fine-tuning mechanisms are added to precisely match rotational speed and torque, then the manufacturing precision of the drilling process is improved, but the ease of operation deteriorates

Engineering Contradiction:
Improveprecision of matching rotational speed and torqueVSAvoidease of gear selection and fine-tuning
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The control device automatically performs the fine-tuning of rotational speed and torque based on signals from sensors that detect drill bit diameter and material properties. The system self-regulates without requiring manual intervention, eliminating the complexity of manual fine-tuning operations while maintaining high precision in matching drilling parameters

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates sensors that detect drill bit diameter and material hardness, transmitting signals to the control device which then automatically adjusts the motor speed. This closed-loop feedback system ensures precise matching of drilling parameters without requiring operator expertise or manual fine-tuning

Inventive Principle:
Principle #23Feedback

3Device complexity

If manual gear selection and fine-tuning is used, then the device complexity is reduced, but the productivity decreases due to time-consuming adjustments

Engineering Contradiction:
Improvesimplicity of gearbox structureVSAvoiddrilling efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent replaces manual mechanical gear selection with an electronic control system that automatically adjusts motor speed based on sensor inputs. This substitution eliminates time-consuming manual adjustments and fine-tuning operations, significantly improving drilling productivity while maintaining straightforward gearbox architecture

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The control device is pre-programmed with the relationships between drill bit diameter, material properties, and optimal rotational speed. When sensors detect the drill bit parameters, the control device immediately calculates and applies the appropriate speed setting without requiring manual intervention, eliminating delays and improving productivity

Inventive Principle:
Principle #10Preliminary action

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

Enables precise adjustment of rotational speed and torque to match drill bit diameter, enhancing the efficiency and protection of the drilling process while avoiding costly fine-tuning procedures.

Implementation Method 1

a Maltese cross gear for transmitting a movement of the operating device to the shift fork

Methodology Applied
Scientific EffectGeneva Drive: Geneva Drive

Implementation Method 2

at least one signal transmitter and at least one sensor for receiving at least one signal from the at least one signal transmitter

Methodology Applied
Scientific EffectHall Effect: Hall Effect

Data Source

PatentEP3421183B1Electromechanical gear selection device with a geneva gear
Publication Date: 2021.05.26 HILTI AG
  • EP3421183B1 patent drawingFigure 1
  • EP3421183B1 patent drawingFigure 2
  • EP3421183B1 patent drawingFigure 3

AI summary

Method for a machine tool transmission (1), wherein the machine tool includes an electric motor (3) and a control unit (18), and the transmission (4) includes an operating device (7) for gear selection in the transmission, a shift fork (13), and a Maltese cross gear (12), wherein the operating device includes a signal transmitter (15) and a sensor (16) for receiving the signal from the signal transmitter.The method includes: - moving the operating device from a first to a second position; - receiving a signal from the sensor corresponding to the second position of the operating device; - sending the signal to the control unit; - adjusting the speed of the electric motor from a first to a second value by the control unit; - moving the operating device from the second to the third position; - moving the Maltese cross gear from a first to a second position corresponding to the third position of the operating device; and - moving the shift fork from a first to a second position to shift from first to second gear. Furthermore, a machine tool and a gearbox are provided for carrying out the method.