Cam and follower arrangement, and monochromator of a spectrophotometer including such an arrangement.

摘要

A cam and follower arrangement in which the cam consists of a track (21), carried by a rotatable member (12), and has one or more abrupt directional transitions (30) and the follower (17) is biassed to engage one wall or the other (31, 32) of the track (21) appropriate to the direction of rotation of the member (12), by means including a direct-current electric motor (20) operated in a stalled condition. The arrangement is employed in a monochromator for spectrophotometric apparatus to drive a filter-holder 18, to position one of a number of optical filters (22, 23, 24, 25) in the incoming beam of light (26).