Linkages guide and change movement — Engineering, 11–13 years
Connected bars can pass movement around corners or change a push into a different path. Engineering, 11–13 years.
What a linkage is
A linkage is a set of rigid bars joined by pivots or sliding joints. When one bar moves, the connections make the others follow a limited path. By choosing the bar lengths and joint positions, engineers can turn a push into a swing, a lift or a guided straight movement.
Why linkages solve a problem
A motor or a person's hand may move in a circle or along one short path, while the job needs a different movement somewhere else. A linkage connects these two needs without requiring a separate motor for every part. Engineers developed many arrangements to control motion while keeping parts simple and reusable.
A four-bar linkage
Fix one 10 cm bar to a board with pivots 8 cm apart, then attach a second 6 cm bar to the first and a third 10 cm bar between the free ends. As the first bar turns, the last bar swings while staying connected to both joints. The bars guide its end instead of letting it move anywhere.
The reasonable mistake
It is reasonable to expect a straight bar to make its end move straight. A bar pinned at one end actually makes the other end travel along an arc, because its distance from the pivot stays fixed. A linkage uses several such arcs together to create a path that is straighter or more useful.
Where linkages are used
Windshield wipers use linkages to make one motor move two blades back and forth. Folding chairs and adjustable lamps use them to change position while keeping parts connected. Some walking robots also use linked legs, so one motor can create a repeated step-like movement.
Keep exploring
Other languages
Loading MyLeoNes™…