Page 478 - Cam Design Handbook

THB14 9/19/03 7:58 PM Page 466

466 CAM DESIGN HANDBOOK

FIGURE 14.11. Circular arc cam—translating roller follower.

E 1 equal to distance AB 3 and a connecting rod length M 1 equal to B 3C. Equations (14.2),
(14.6), and (14.7) can be used to give the follower action.

14.9 TANGENT CAM—TRANSLATING
ROLLER FOLLOWER

This cam is often called a tangent cam because it consists of straight lines drawn tangent
to circular arcs. On the cam in Fig. 14.12, we see straight sides for portions K 0K 1 and
K 2 K 3 . Nose arc K 1 K 2 is a circle with center at B 2 and arc K 0 K 3 is the dwell base
circle radius R b . The previous results of Sec. 14.7 apply for the circular arc portions of the
cam. However, additional equations are needed for the straight-side portions K 0 K 1 and
K 2 K 3 . Let
q t = cam angle to a point on straight-side flank, deg.

It can be shown that the follower displacement on straight sided range K 0 K 1 and K 2 K 3
y = ( R + R )(secq - ) 1 in. (14.12)
b r t
Differentiating gives velocity and acceleration
v = ( R + R )w sec q tan q ips (14.13)
t
t
b
r