  The optimization of the pressure angle in a cam-follower transmission is
reported in this paper. This transmission is based on Slide-o-Cam, a cam
mechanism with multiple rollers mounted on a common translating follower. The
design of Slide-o-Cam, a transmission intended to produce a sliding motion from
a turning drive, or vice versa, was reported elsewhere. This transmission
provides pure-rolling motion, thereby reducing the friction of rack-and-pinions
and linear drives. The pressure angle is a suitable performance index for this
transmission because it determines the amount of force transmitted to the load
vs. that transmitted to the machine frame. Two alternative design strategies
are studied, namely, (i) increase the number of lobes on each cam or (ii)
increase the number of cams. This device is intended to replace the current
ball-screws in Orthoglide, a three-DOF parallel robot for the production of
translational motions, currently under development at Ecole Centrale de Nantes
for machining applications.
