Page 81 - Cam Design Handbook

THB3 8/15/03 12:58 PM Page 69

MODIFIED CAM CURVES 69

At point A substituting
h¢ h¢
y = y = - = 0091 h¢
.
1
A
4 2p
h¢w h¢(31 4 . )
y = = = 22 5 . h¢
˙
A
¢ b 80
p
180
2pw 2
h¢
˙˙ y = A =
A
2
() 2
¢ b
2p h¢(31 4 . ) 2
= 2 = 3170 h¢
Ê 80 p ˆ
Ë 180 ¯
The displacement of part 2, the parabolic curve, in Sec. 2.6
q 1 Ê q 2 ˆ 2
y = v 2 + A
2 A 2 Ë ¯
w 2 w
Substituting, we obtain
h¢
h¢w q 1 2pw 2 Ê q 2
y = 2 + 2 ˆ
2 2 Ë ¯
¢ b w 2 () w
¢ b
h¢q h¢pq 2
= 2 + 2
¢ b () 2
¢ b
h¢ Ê ˆ
1
= + h¢p = . h¢
1 285
2 Ë ¯
4
Also, the velocity at point B
q
˙ y = v + A 2
B A 2
w
Ê 40180 ˆ
p
= 22 5 h¢ = 93 3
. h¢ + 3170
. h¢
Ë 31 .4 ¯
The displacement of part 3
p
q h¢ Ê 20180 ˆ h¢
˙ y = v 3 + = 93 3 + = . 1 199 h¢
. h¢
3 3 Ë ¯
w 2p 31 .4 2p
we know that
y + y + y = 2
1 2 3
Substituting,
0091 ¢ + 1 285 ¢ + 1 199 ¢ = 2
h
h
.
.
h
.
.
h ¢ = 07767 in
Let us now find the displacements:
y = . ( . 0071 in
0091 07767) = .
1
y = . ( . 0998 in
1 285 07767) = .
2
y = 1 191 07767) =. ( . 0896 in
.
3