shuttle
杼 centers on a shuttle, the tool used in weaving to carry thread back and forth across the loom.
杼 combines 木 (wood) with 予, which likely contributes the sound. The character originally referred to a wooden shuttle used in weaving.
The left side 木 is wood, and the right side 予 looks like a shuttle moving back and forth. Picture a wooden shuttle sliding through the threads on a loom.
For チョ, imagine a weaver named Cho who expertly throws the wooden shuttle: Cho -> チョ, and the shuttle flies across the loom.
shuttle (of a loom)