Deck 16: Cams

Question 1

The cam follower should be slightly offset from the center of the cam to allow for abrupt changes in motion.

Answer 1

False

Question 2

A displacement diagram is a designed layout of the required motion of the cam.

Answer 2

True

Question 3

A working circle is considered a distance equal to the distance from the center of the cam shaft to the highest point on the cam.

Answer 3

True

Question 4

The working circle is also known as the:

A)diameter
B)height
C) radius
D) circumference

Question 5

Which of the following is not a type of motion produced by a cam?

A)harmonic
B)uniform acceleration
C) uniform velocity
D) harmonic displacement

Question 6

The length of a displacement diagram represents one complete revolution of the cam.

Question 7

The two major kinds of cams used in industry are radial arm and parallel.

Question 8

A radial arm cam essentially changes rotary motion into either up-and-down motion, or rocking action.

Question 9

The shaft of a the follower on a cylindrical cam must rotate or the cam will stop.

Question 10

Which of the following is not true regarding a timing diagram?

A)It is used when more than one cam is attached to the shaft.
B)Each cam works independently.
C) Each cam works dependently.
D) Each cam must function in relation to the other cams.

Question 11

Which of the following is not true regarding the design and layout of the cam displacement diagram?

A)The bottom line of the displacement diagram is the baseline.
B)All dimensions should be measured up from the baseline.
C) The length of the displacement diagram is usually drawn equal in length to the circumference of the working circle.
D) A displacement diagram is a designed layout that measures the applied load.

Question 12

Dwell is the period of time during which the follower moves.

Question 13

The height of the displacement diagram is equal to the radius of the working circle.

Question 14

The rotation of a cam is not necessary to label on the diagram since they can move in either direction.

Question 15

Speed of rotation and the actual load applied on the lifter determines the type of follower to be used.

Question 16

A base circle radius equals the distance from the center of a shaft to the center of a follower wheel at its lowest position.

Question 17

If the cam profile is clockwise, it should also be laid out clockwise.

Question 18

Which of the following is not true regarding cam motion?

A)With uniform velocity, there is a very rough stop and start.
B)Harmonic motion is very smooth, but the speed is not uniform.
C) Harmonic motion is very smooth, the speed is uniform.
D) Uniform acceleration is the smoothest motion.

Question 19

On a radial arm cam, the follower is perpendicular to the cam shaft.

Question 20

A working circle is equal to 360 degrees.

Question 21

When dimensioning a cam be sure to include:

A)degrees from the starting point
B)the distance from the center
C) the arc length
D) both A and B

Question 22

The part of the cam system that moves in an up and down motion is called the:

A)cam
B)follower
C) shaft
D) roller bearing

Question 23

When drawing a displacement diagram, divide the sections into equal portions of:

A)15 degrees
B)30 degrees
C) 45 degrees
D) 60 degrees

Question 24

The length of the baseline is equal to the:

A)height times the radius
B)working circle circumference
C) diameter of the cam at the largest point
D) circumference of the shaft

Question 25

A displacement diagram shows the:

A)required motion of the cam
B)change in vertical distance of the follower
C) layout for a pattern development of the cam
D) distances from the shaft center to the shapes on the cam

Question 26

When drawing a cam with an offset follower, the first step should be to:

A)lay out the baseline
B)determine the cam and follower data
C) make a layout displacement diagram
D) divide the cam into equal segments

Question 27

When more than one displacement diagram is shown at the same time, it is called a:

A)timing diagram
B)follower motion diagram
C) baseline diagram
D) working circle diagram

Question 28

Which of the following is not a type of follower?

A)lifter face
B)pointed
C) flat face
D) roller

Question 29

To lay out a uniform acceleration motion on a displacement diagram, divide the designed rise/fall into:

A)18 equal parts
B)12 equal parts
C) 36 equal parts
D) 9 equal parts

Question 30

Which of the following is not true regarding the length of the displacement diagram?

A)The length of the displacement diagram represents one complete revolution of the cam.
B)The length of the displacement diagram is usually drawn equal in length to the circumference of the working circle.
C) The height of the displacement diagram is equal to the radius of the working circle.
D) The height of the displacement diagram is equal to the circumference of the working circle.

Question 31

The time it takes for the cam to move the follower to the designed height is known as the:

A)time radius
B)ime interval
C) time period
D) time increment

Question 32

he distance between the center of the camshaft and the outermost point is referred to as the:

A)diameter
B)circumference
C) working circle
D) operational radius

Question 33

If the displacement diagram forms a sharp point at the peak, it must be _____ cam motion.

A)uniform velocity
B)modified uniform velocity
C) harmonic motion
D) none of the above

Question 34

The time in which the follower does not move is referred to as the:

A)harmonic motion
B)base circle
C) roller stretchout
D) dwell

Question 35

If the start and stop of a cam is to be very rough, the displacement diagram will contain:

A)a peak at the top
B)many curves
C) straight angled lines
D) at least 15 degrees of dwell