TABLE OF CONTENTS The previous chapter discussed a number of acceptable cam functions for the double-dwell case, i.e., any rise or fall that lies between dwells. This chapter will describe a set of functions that behave in an acceptable manner at moderate to high speeds for single-dwell applications. The variables used in this chapter are the same as those defined in Table 2-1 (p. 18).
If your need is for a rise-fall (RF), critical extreme position (CEP) motion, with no dwell, then you should really be considering a crank-rocker linkage, rather than a cam-follower, to obtain all the linkage's relative advantages of reliability, ease of construction, and lower cost. If your needs for compactness outweigh those considerations, then the choice of a cam-follower in the RF case may be justified. Also, if you have a critical path motion (CPM) design specification, and the motion or its derivatives are defined over the interval, then a cam-follower system is the logical choice even in the RF case.
Many applications in machinery require a single-dwell cam program, rise-fall-dwell (RFD). Perhaps a single-dwell cam is needed to lift and lower a roller which carries a moving paper web on a production machine that makes envelopes. This cam's follower lifts the paper up to one critical extreme position at the right time to contact a roller which applies a layer of glue to the envelope flap. Without dwelling in the up position, it...
