Parallel and push-pull linkages | Design and technology

Starter quiz

What is another word for a fulcrum?
- fixed pivot
- loose pivot
- pivot point ✓
- centre point
Which of the following describes a lever?
- a rigid bar that does not turn
- a rigid bar that does not bend ✓
- a rigid bar that bends when force applied
Complete the following sentence. A reverse motion linkage creates movement that is ...
- in the same direction.
- in opposite directions. ✓
- in a downward direction.
- in an upward direction.
A reverse motion linkage contains ...
- one fixed pivot. ✓
- two fixed pivots.
- three fixed pivots.
- four fixed pivots.
- five fixed pivots.
Match the definitions
- input
  
  ⇔
  
  starts the mechanism ✓
- output
  
  ⇔
  
  the outcome of the mechanism ✓
- mechanism
  
  ⇔
  
  a set of moving parts that make something happen ✓
- linkage
  
  ⇔
  
  a mechanism connecting levers together ✓
Which of the following is the word used to describe a mechanism that connects levers together?
- Fulcrum
- Pivot
- Linkage ✓
- Lever

To create movement, a parallel linkage must have ...
- all loose pivots.
- fixed and loose pivots. ✓
- all fixed pivots.
How does a parallel linkage move?
- side-to-side, with the input and output not moving in any direction
- side-to-side, with the input and output moving in the same direction ✓
- side-to-side, with the input and output moving in opposite directions
Which of the following explanations are the best description for parallel linkages?
- one pair of parallel levers
- two pairs of parallel levers ✓
- three pairs of parallel levers
- four pairs of parallel levers
How many fixed pivot points does a push-pull linkage usually have?
- 'Two' ✓
Match the words to the definition.
- loose pivot
  
  ⇔
  
  a free moving point that joins two levers together ✓
- fixed pivot
  
  ⇔
  
  a point that joins a lever to one place ✓
- input
  
  ⇔
  
  the motion used to start a mechanism ✓
- output
  
  ⇔
  
  the motion caused by the input ✓
What happens to the input and output movements on a push-pull linkage?
- They move in opposite directions.
- They move apart.
- They move in the same direction. ✓

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A parallel linkage contains fixed pivots and allow movement back and forth and side to side.
A push-pull linkage allows the input and output levers to move in the same direction.

Push-pull and parallel linkages are made of more than one lever.

Levers can be joined together to form a linkage. A parallel and push-pull linkage is made up of multiple levers.

Parallel linkage - a linkage that creates movement in the same direction using two pairs of levers
Input - something that goes into a system
Output - something that comes out of a system
Push-pull linkage - a linkage that uses short levers to push and pull three other levers in the same direction