sedan
篼 centers on a sedan chair or palanquin, a covered seat carried on poles. The given meaning 'sedan' refers to this type of conveyance.
篼 combines 竹 (bamboo) with 兜 (helmet/hood), likely indicating a bamboo-framed covered conveyance. The exact historical development is uncertain.
Bamboo 竹 over a helmet-like cover 兜: picture a bamboo-framed sedan chair with a hooded top, carrying someone in a covered seat.
For トウ, imagine a toe poking out from under the sedan's bamboo cover: toe -> トウ, and the sedan carries the person whose toe is visible.