To investigate simplest intermittent motion mechanism

Abstract

Intermittent motion mechanisms or indexing mechanisms provide unidirectional output motion with intermittent dwells. These may be discontinuous contact type (engagement - disengagement type) or continuous contact type. The continuous contact devices do not have, at least in principle, the dynamic problems of engagement and disengagement of elastic machine parts, hence, they are preferred. The most common method to use a disc cam and roller to act as a fully rotating input link, driving a reciprocating or oscillating roller follower. In the present context the requirement is full rotational motion for both the input and output links. In addition dwells are required in the output motion. In this paper, a mechanism consisting of a single roller crank and a single cam is investigated fundamentally for the requirements of rotational and dwell conditions of an indexing mechanism. The dwell requirement excludes the use of roller-crank as the output and the fully-rotating rollercrank imposes reciprocating contact on the cam, ie, it demands a partial cam. Roller-crank must be longer than the fixed link when cam is required to rotate fully.