Hand Tools

1
Hand Tools

• Manual hand tools enable performance of tasks
  that would be difficult or impossible to perform
  without the tools.
• Power hand tools provide additional benefit of
  replacing operators strength.

2
Hand Tool Requirements

• Should perform well the function for which it is
  intended
• Should be properly proportioned to the operators
  body dimensions
• Should be adjusted to the strength and work
  capacity of the operator
• Should not cause premature fatigue
• Should be adapted to the operators sensory
  capacities
• Should be inexpensive to purchase and maintain

3
Problems with Poorly Designed Hand Tools

• Pinching, crushing and amputation of fingers
• Entry of foreign objects into eyes
• Straining or tearing of muscle tendons
• Inflammation of hand/wrist tendon sheaths
• Back pains
• Muscle or Mental fatigue
• Long operator learning times

4
Tool Guidelines

• Use special-purpose tools
• Design tools to be used by either hand
• Power with motors rather than muscles
• Use the proper grip
• Make the grip the proper size
• Make the grip surface compressible, smooth
• Consider the usage angles
• Use the appropriate muscle group

5
Tool Handles

• Design goal is to maximize forces produced while
  minimizing physical stress
• When the wrist deviates from neutral, the amount
  of stress on nerves and tissues increases
  significantly
• Premature fatigue can be minimized with the
  proper tools