拉紧,紧线器
Take-up \Take"-up`\, n. (Mach.) That which takes up or tightens; specifically, a device in a sewing machine for drawing up the slack thread as the needle rises, in completing a stitch.
take-up n 1: a device for reducing slack or taking up lost motion 2: the action of taking up as by tightening or absorption or reeling in