Grades K–2 · Machines
How does an umbrella spread its little roof?
An umbrella is a little roof that can fold. Its cloth rests on thin ribs. The ribs join the top of the middle pole, so they can swing outward or fold down beside it.
In the diagramOne sliding ring moves the ribsTwo ribs shown · cloth and hinges simplifiedRibSliding ringShort supportThe ring moves up; the linked ribs spread outward.
Below the top is a ring that slides along the pole. Short bars join this ring to the ribs. Pushing the ring upward moves these bars. Because their ends are joined, the bars push the ribs outward together. The cloth spreads across them.
A catch holds a manual umbrella open. When the catch is released, the ring can slide down and the ribs fold in. The cloth is carried by the moving frame. Different umbrellas add different springs or extra folding joints, but this drawing shows the simple linked frame.
About this explanation
Starting knowledge: Recognize turning, opening and closing.
Sources
- ACME Umbrella — Umbrella structure