Cams Flashcards
Cam
changes the input motion, which is usually rotary motion (a rotating motion), to a reciprocating motion of the follower.
Where are cams found mm
They are found in many machines and toys
What are the 2 parts of a dam
FOLLOWER and the CAM PROFILE.
Explain how cams work using the diffamation
diagram 1= cam is in a vertical position
Diagram 2=slow rotates in an anticlockwise direction.
Diagram 3=as it rotates the follow drops down.
diagram 4 =the follower is in its lowest position.
Diagram 5=com continues to rotate follower rises
diagram 6 = it returns to its original position.
One cycle
One rotation/revolution of the cam
Dwell
When the cam rotators but the follower does not rise or fall
The rise
That part of the cam that causes the follower to rise
What do all followers do
they all slide or roll on the edge of the cam.
What happens a pear shaped cam
As the handle is turned the model moves backwards and forwards
Talk about the motion of a pear shaped cam
The movement is gentle although the faster the handle is turned the faster the movement of the model becomes
Name throes of followers
Flat follower
Point/knife follower
Roller follower
Offset follower
Describe a flat follower
Large flat surface
Can’t follow precise cam
Cam=rotary motion
Follower=reciprocating motion
Point knife follower
Mainly works with heart shaped
Detailed profile
Hard steep tips
Goes into tight curves
Roller follower
Small roller
Reduces friction and wear and tear between cam and follower
Offset follower
Slant straight bottom
Name 4 types of follower
Flat follower
Point knife follower
Roller follower
Offset follower
What determines which type of cam profile to use
The way the follower needs to move
Pear cam profile
Used in shafts of cars
follower remains motionless for about half of the cycle
Second half rises and falls
Pear shape calms caused the follower to rise rapidly as it comes into contact with the bump part of the cam .
Rise and fall happens with equal speed
Eccentric
Circular cam
smooth motion.
used in steam engines and pumps.
This camp profile is a circle.
rotation is offset from the centre of the circle
the calm causes rise and fall in a movement known as the simple harmonic rotation.
Heart cam
Heart shaped cams allow the follower to rise and fall with uniform velocity. These can cause the follower to rise at the height which remains constant until the follower reaches the grove where it falls sharply at a uniform rate before rising again. These are used to wind threads or sewing machines. 
Drop(snail) cam
-causes the follower to rise slowly then fall sharply into the step
- ensure that the rotation of a snail cam is smooth vertical centre line of the cam must be positioned slightly off centre.
-used in cutting produce when the blade is required to fall sharply.
What are 4 types of joints and what is the strongest
Butt joint
Dowel joint
Finger joint
Dove tail joint=strongest
