Overview
ISO 447:1984 - Machine tools - Direction of operation of controls defines ergonomic and functional rules for the direction of operation of controls on machine tools. This second edition (1984) replaces ISO 447:1973 and applies to controls that produce movement of a machine tool component in one of two opposing directions. The standard explicitly excludes controls for components that rotate continuously in the same direction during normal machine functioning (for example, electric motor start/stop controls).
Key topics
- Scope and applicability
- Rules apply to controls that cause opposing movements (linear or circular) of machine tool components.
- Continuous-rotation controls (e.g., motors) are excluded.
- Lever control
- Lever travel should be oriented so the line joining extreme handle positions is approximately parallel to the controlled component’s rectilinear movement.
- For circular movements, the lever’s rotation plane should be parallel to the component’s plane of rotation.
- Push-button control
- Lines of fixed push-buttons should be placed parallel to the movement of the controlled component.
- Operation of the right-hand, furthest, or top button should produce motion to the right, away, or upwards respectively (from the operator’s operating position).
- For movable/pendant controls that can rotate >180°, an outline of the machine must be shown to avoid ambiguity.
- Wheel control
- Clockwise rotation of a wheel (as seen by an operator facing the wheel shaft end) should produce:
- movement towards the centre for clamping devices (chucks), or
- rectilinear movement to the right, away, or upwards depending on wheel orientation.
- Special cases
- If a preselector can change movement direction, the rules apply to the most frequently used direction.
- If one lever starts both cutting and feed movements, rules apply to the feed movement.
Applications
- Machine tool designers and manufacturers: to design intuitive, consistent control layouts that reduce operator error.
- Safety and ergonomic engineers: to align control directions with operator expectations and minimize risk.
- Control panel and pendant suppliers: to implement compliant push-button, lever, and wheel arrangements.
- Maintenance, inspection, and compliance teams: to verify that machine controls follow international conventions and machine indicator plates where exceptions exist.
Related standards
- Developed by ISO/TC 39 (Machine tools). Users should consult other ISO machine-tool safety and ergonomics standards for comprehensive compliance and look for any later revisions or related guidance when implementing control layouts.
Keywords: ISO 447:1984, machine tools, direction of operation of controls, control equipment, lever control, push-button control, wheel control, operator ergonomics, machine indicator plate.
