Design of Controls

Use of a control may require repetitive precision and forceful exertions. The following strategies should be used to design or select tools with appropriate controls:

• Controls should be designed for use by either hand.
  
  

  For tasks requiring force exertions for prolonged duration, the controls should be designed for activation by thumb muscles. A locking mechanism can be useful in reducing muscle effort, where it does not cause a safety hazard.
  
  

  Tools that require several fingers to operate should be mounted or suspended.
  
  

  Control appropriate for the task should be selected.
  
  

  The force to activate the controls should be below 2.25 pounds force (10 Newtons).