roller board and arms（滚轮板与连杆）是什么意思？音标发音+图解场景

滚轮板与连杆 /ˈɹəʊlˌʌp ˈblaɪnd/ n

English: roller board and arms · 滚轮板与连杆

释义：Group of trackers and rollers connecting the keys of a manual to the corresponding pallets.

这个词出现在以下图解场景（1）