Question

Shown are schematic diagrams of a single arm of a 3-fold umbrella. Identify the correct representation(s).

• A. A
• B. B
• C. C
• D. D

Hint:

For foldable linkages, check: collinear alignment in the open state, alternating pivot directions for collapse, and the correct count of links/hinges.

Answer 1

The Correct Option is B

A 3-fold umbrella rib has three links that align collinearly when open and zig-zag fold around alternating pivots when closed.
The correct schematic must show:
1) three segments with two intermediate hinges plus the root joint near the shaft,
2) alternating hinge directions so the links can collapse toward the shaft, and
3) equal ``open-linearity''—all links lie on one straight line in the deployed state.
Among the options, only (B) places the hinges and link orientations to satisfy all three conditions; the others misplace a hinge or orientation, preventing proper fold/open kinematics.
\[ \boxed{\text{Correct: (B)}} \]