A plate cam with an offset reciprocating roller follower has a dwell of 60◦ and then rises in 90◦ to another dwell of 120◦, after which it returns in 90◦

of cam rotation. The radius of the base circle is 40 mm, the radius of the roller follower is 15 mm, and the follower offset is 20 mm. For the rise motion 60◦ ≤ Θ ≤ 150◦, the equation of the displacement

(the lift) is y = 40 θ

π +sinθ



, where y is in millimeters and θ is the cam rotation angle in radians.

(a) Find equations for the firstand second-order kinematic coefficients of the lift, y, for this rise motion.

(b) Sketch the displacement diagram and the first- and second-order kinematic coefficients for the follower motion described.

Comment on the suitability of this rise motion in the context of the other displacements specified. At the cam rotation angle Θ = 120◦, determine the following:

(c) the location of the point of contact between the cam and follower, expressed in the moving Cartesian coordinate system attached to the cam;

(d) the radius of curvature of the pitch curve and the radius of curvature of the cam surface; and

(e) the pressure angle of the cam. Is this pressure angle acceptable?