Two-Stage Safety Braking for Fast Machine Tool Stopping
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Solution Overview
Problem
Existing safety braking devices for machine tools do not effectively manage rotational energy dissipation during braking processes, leading to potential hazards for users, as they often rely on high currents that can damage electronics and require complex mechanical components for rapid stopping.
Innovation Solution
A two-stage braking system is implemented, where the first electronic braking stage uses counter-control of an electric motor to initiate braking upon user approach, and a second mechanical braking stage, such as a claw clutch, ensures rapid and safe stopping upon user contact, reducing stress on components and enabling faster braking times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a single-stage mechanical braking system is used to stop the machining tool rapidly, then the braking time is reduced, but the mechanical components are subjected to high stress and require complex design
Solution Approach 1:
The braking process is divided into two distinct stages: an electronic braking stage that handles initial deceleration and a mechanical braking stage that handles final stopping. This segmentation allows each stage to be optimized independently, reducing the complexity and stress on mechanical components while maintaining rapid overall braking time.
Solution Approach 2:
The patent replaces part of the mechanical braking system with an electronic braking mechanism. The electronic braking stage uses electrical control to dissipate rotational energy, substituting for what would traditionally require purely mechanical solutions and reducing the burden on mechanical components.
2Loss of time
If high currents are used to brake the electric motor rapidly, then the braking time is reduced, but the electronics are damaged
Solution Approach 1:
The braking process is divided into two distinct stages: an electronic braking stage that handles initial deceleration and a mechanical braking stage that handles final stopping. This segmentation allows each stage to be optimized independently, reducing the complexity and stress on mechanical components while maintaining rapid overall braking time.
Solution Approach 2:
The electronic braking stage applies partial braking action to reduce rotational speed to a safe level, rather than attempting to stop the motor completely through electronic means. This partial action prevents excessive current demands that would damage electronics, while the mechanical stage completes the stopping process.
3Reliability
If a two-stage braking system is implemented, then the stress on components is reduced and braking safety is improved, but the device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it detects user approach, controls the electronic braking stage, and activates the mechanical braking stage. This multi-functionality reduces the need for separate dedicated components for each function, thereby reducing overall system complexity despite the two-stage braking approach.
Solution Approach 2:
The sensor unit automatically detects when a user approaches the machining tool and triggers the appropriate braking stage without requiring manual intervention. This self-service capability simplifies the user interface and reduces the complexity of control mechanisms by using automatic sensor-based activation.
4Loss of time
If the sensor unit detects user approach early, then the braking time is reduced, but the system requires more sensitive detection
Solution Approach 1:
The braking process is divided into two distinct stages: an electronic braking stage that handles initial deceleration and a mechanical braking stage that handles final stopping. This segmentation allows each stage to be optimized independently, reducing the complexity and stress on mechanical components while maintaining rapid overall braking time.
Solution Approach 2:
The sensor unit detects user approach at an early stage and triggers the electronic braking stage before the user reaches a dangerous distance. This preliminary detection and action allow the system to begin deceleration early, reducing the total stopping time required while managing the sensitivity requirement through staged response.
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 two-stage braking system achieves rapid and safe stopping of machine tools, enhancing user safety by dissipating rotational energy efficiently and extending the service life of components, while allowing for simpler and more compact design.
Implementation Method 1
the first electronic braking stage uses counter-control of an electric motor to initiate braking
Implementation Method 2
a second mechanical braking stage, such as a claw clutch, ensures rapid and safe stopping
Data Source
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AI summary
The invention relates to a safety braking device (32) for a machine tool (10) for braking a processing tool (28) driven by means of an electric motor (20) via an output unit, more particularly an output shaft (26), comprising at least one braking device which is provided to halt rotation of the output unit in a braking process. According to the invention, the braking device has at least a first braking stage (22) and a second braking stage (24). The invention further relates to a machine tool (10) comprising the safety braking device (32) according to the invention and to a method for operating a safety braking device (32) according to the invention.