expanding pulley

A pulley whose perimeter is made expansible, as a means of varying the speed of the belt thereon. [EXPANSION-DRUM.] expanding-reamer, s. A reamer which has a bit or bits extensible radially after entering a hole, so as to enlarge the hole below the surface. *ex-păn'se, v. t. [Lat. expansus , pa. par. of expando .] To expand, to spread, to open. "Belerophon's horse, framed of iron, was placed between two loadstones, with wings expansed , pendulous in the air."-Browne: Vulgar Errors , bk. ii., ch. iii.