Machine Tool Safety Control With Zoned Speed Restoration
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Solution Overview
Problem
Traditional safety systems for machine tools do not adequately minimize risks for operators by failing to efficiently manage the movement speed of movable elements, particularly in scenarios where operators need to access and exit zones around the machine tool safely.
Innovation Solution
A safety system with a delimitation structure, multiple presence detectors, and voluntary activation devices that control the movement speed of movable elements, allowing operators to safely access and exit zones by sequentially activating buttons to restore normal operating speed after reducing it upon entry into a danger zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional safety systems use presence detectors to monitor operator zones, then operator safety is improved, but the system cannot efficiently manage movement speed restoration after operator exit
Solution Approach 1:
The safety system divides the operator access area into multiple zones (first zone, second zone, third zone) with different safety requirements. Each zone has its own presence detector and voluntary activation device, allowing granular control of movement speed based on operator position. This segmentation enables the system to restore normal speed more efficiently once operators have safely exited specific zones.
Solution Approach 2:
The control system continuously receives feedback from presence detectors monitoring operator positions in different zones. Based on this feedback, the system automatically adjusts movement speed and manages the restoration process. The voluntary activation devices provide additional feedback when operators confirm safe exit, enabling efficient speed restoration while maintaining safety.
2Object-affected harmful factors
If the system automatically lowers movement speed when operators enter danger zones, then collision risks are reduced, but productivity decreases due to prolonged speed reduction
Solution Approach 1:
The system dynamically adjusts movement speed based on real-time operator presence in different zones. Instead of maintaining a fixed reduced speed, the system optimizes speed parameters according to the current safety situation, allowing faster operation when zones are clear and slower operation when operators are present. This dynamic adjustment minimizes productivity impact while maintaining safety.
Solution Approach 2:
The system prepares for speed restoration in advance by monitoring zone exits and pre-configuring the conditions for resuming normal operation. When operators exit danger zones, the system is already ready to restore speed through the voluntary activation devices, minimizing the duration of speed reduction and thereby reducing productivity impact.
3Reliability
If multiple presence detectors and voluntary activation devices are added to the safety system, then operator safety is enhanced, but device complexity increases
Solution Approach 1:
The control system serves multiple functions: it monitors presence in all zones, determines operator position, controls movement speed, manages restoration sequences, and processes voluntary activations. By making the control system multi-functional, the patent avoids adding separate dedicated devices for each function, thereby enhancing safety without proportionally increasing overall system complexity.
Solution Approach 2:
The system combines presence detection and voluntary activation functions into an integrated control architecture. The control system processes information from all presence detectors and coordinates all voluntary activation devices centrally, merging multiple safety functions into a unified system that manages complexity through integration rather than multiplication of separate components.
Data Source
Figure 1
AI summary
The present invention relates to a safety system (1) for a machine tool (2) provided with at least one movable element (4). Such safety system (1) comprises: a delimitation structure (5) which is provided with an opening for access of an operator; a first presence detector (F1, R1) which defines, together with said delimitation structure (5), a first zone (Z1); a first voluntary activation device (P1), which is placed outside said first zone (Z1); a second presence detector (F2, R2) defining a second zone (Z2) and a third zone (Z3), at least one passage (C) being defined between said third zone (Z3) and said second zone (Z2); a second voluntary activation device (P2), which is placed in said third zone (Z3); and a control system to control the movement speed of the movable element (4), such that when an operator accesses said third zone (Z3) the control system orders said at least one movable element (4) to move with a first speed, and such that when said first voluntary activation device (P1) is subsequently activated said control system orders said at least one movable element (4) to move with a second speed which is higher than said first speed, and such that when an operator moves from said third zone (Z3) to said second zone (Z2), the control system orders said at least one movable element (4) to move with said second speed after activating, sequentially, said second voluntary activation device (P2) and said first voluntary activation device (P1). The present invention also relates to a safety method for a machine tool (2).