The term 'kuiuchi-yagura' (a pile-driving tower) refers to a temporary structure which is built by constructing logs and steel pipes, and this is used as a machine to drive in piles at a foundation work.
杭打ち地業の際に杭を打つ装置として、丸太や鋼管などを組んで建てた仮設の構造物を「杭打ちやぐら」という。