Movable Protective Sleeve for Safe Robot Machining End Effectors

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Solution Overview

Problem

Existing robot systems for machining workpieces do not adequately prevent injuries from forces exerted during processing, as they lack mechanisms to ensure that a person's body is not between the tool and the workpiece.

Innovation Solution

A robot system with a sleeve that can be securely retracted into a protective position when not in use, featuring a spring or restoring mechanism for automatic return and a sensor for proximity detection to prevent accidental contact, ensuring the sleeve is only exposed near the workpiece when necessary, and an energy converter and control unit for actuating the tool only when safe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the tool is exposed during machining operations, then productivity and ease of operation are improved, but safety deteriorates as body parts can be positioned between the tool and workpiece

Engineering Contradiction:
Improvemachining operation efficiencyVSAvoidinjury risk to person's body
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The sleeve is designed to be movable between a protective position (covering the tool) and a working position (exposed for machining). The dynamic repositioning allows the system to adapt to different operational states: safe during approach/retreat, and accessible during machining, thus resolving the contradiction between safety and productivity

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sleeve acts as an intermediary protective element between the tool and the surrounding environment. It provides physical shielding when in the protective position, preventing direct contact between the tool and body parts, while allowing the tool to be exposed when machining is required

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the sleeve is locked in protective position, then safety is improved by preventing body contact, but ease of operation deteriorates as the tool cannot be exposed for machining

Engineering Contradiction:
Improveprotection from force exertionVSAvoidtool accessibility for machining
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The locking mechanism is designed to be state-dependent: it automatically locks the sleeve in the protective position during approach and retreat phases, but can be released during machining operations. This dynamic locking behavior ensures safety when needed while allowing operational flexibility when required

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses sensors to automatically detect the presence of body parts and trigger the locking mechanism without requiring manual intervention. The sleeve self-locks when a body part is detected between the tool and workpiece, and self-unlocks when the body part is removed, providing autonomous safety management

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If a locking mechanism is added to secure the sleeve, then safety is improved, but device complexity increases

Engineering Contradiction:
Improveprevention of accidental contactVSAvoidstructure with locking element and sensor
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The locking mechanism is integrated with a sensor system that automatically detects body parts and triggers locking/unlocking actions without requiring external control or complex manual operation. This self-service approach minimizes the complexity of control systems while maintaining high safety functionality

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The locking mechanism is combined with the sleeve structure and sensor system into an integrated assembly. The locking element, sensor, and sleeve form a unified system where the sensor detects body parts and automatically actuates the locking mechanism, reducing the need for separate control systems and minimizing overall complexity

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

Effectively prevents injuries by ensuring no part of the body can be between the tool and workpiece during force application, allowing precise and safe machining operations.

Implementation Method 1

A spring or other restoring device generating a restoring force can be provided to actuate the sleeve in the protective position

Methodology Applied
Scientific EffectSpring: Spring

Data Source

PatentEP3600796B1End effector with movable protective sleeve for machining workpieces, and robot system comprising an end effector
Publication Date: 2023.07.05 ABB (SCHWEIZ) AG
  • EP3600796B1 patent drawingFigure 1~3
  • EP3600796B1 patent drawingFigure 4

AI summary

The invention relates to an end effector (6) for a robot system, comprising a tool holder (12), a tool (1) which is secured to the tool holder (12) in a protruding manner, and a sleeve (17) that can be moved on the tool holder (12) between a protective position, which surrounds the tool (1), and a use position, which is pushed towards the tool holder (12) and releases at least the tip (14) of the tool (1). A blocking element (18) of the end effector (6) can be moved between a blocking position, in which the blocking element blocks the sleeve (17) in the protective position, and a release position, in which the blocking element allows a movement of the sleeve (17) into the use position, in a controlled manner using a sensor (21) which detects the proximity of the end effector (6) to a workpiece (2).