Press-buttons and keys are suitable for starting and stopping and for switching on or off. This type of control is also suitable for foot control, where it should be operated by the ball of the foot.
The following recommendations apply to both hand – and foot-operated controls:
1. The resistance of the push-button should increase gradually and then disappear suddenly to indicate that the button has been activated.
2. The top of the button should have a high coefficient of friction to stop the fingers or feet from sliding off (see Figure 5.2). Where press-buttons are to be activated by the fingers, the concave form is preferable.
3. In order to indicate that the button has been activated, a sound should be emitted if the workplace has low light levels.
Notes: *, not relevant; —, no information
Table 5.2 gives detailed recommendations for push-buttons.