MEPX
Chapter 2 of 10All chapters
  1. 1The simple machines
  2. 2Levers and gears
  3. 3Engines
  4. 4Hydraulics and pneumatics
  5. 5Getting power where it is needed
  6. 6Household machines
  7. 7Electric motors and generators
  8. 8Efficiency and losses
  9. 9Why machines fail
  10. 10Working out an unfamiliar machine

Chapter 2 of 10

Levers and gears

Turning force around a pivot.

Levers

Force times distance from the pivot is torque. Moving the effort further from the pivot, or the load closer, multiplies force at the cost of movement.

  • Three classes depending on where load, effort and pivot sit.
  • A wheelbarrow, a pair of scissors and a fishing rod are one of each.

Gears

Meshed gears trade speed against torque in proportion to their tooth counts. A gearbox exists because engines produce useful power only over a narrow speed range.