A direct route to the reciprocal Bennett linkage

Abstract: The notion of reciprocity between screws is extended by Baker (2000) to put forward the concept of ‘reciprocal linkages’, those governed by screw systems that aremutually reciprocal. In that article, the 13 four-bars of Delassus, including the Bennett ‘isogram’, are so categorized. Presented here is an alternative means of defining the Bennett loop’s reciprocal system and linkage, one based upon the chain’s own geometrical properties rather than its principal screw system