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