Deck 16: Mechanisms: Linkages, Cams, Gears, and Bearings

Question 1

Explain why constant velocity motion is modified with a curve at the bottom and top of the period.

Answer 1

. Constant velocity motion is an abrupt jerk at the beginning and end of the motion period. This is modified by placing a curve at the beginning and end of the rise and fall to reduce shock to the follower.

Question 2

List three types of parallel shafting gears.

Answer 2

. External and internal spur gears, helical gears, herringbone-a double helical gear

Question 3

Which type of cam motion is suited for only very slow speed applications?

Answer 3

. Constant velocity motion

Question 4

List at least four types of cam motion.

Question 5

Name the most commonly used cam follower.

Question 6

Explain the relationship of the motion of the cam follower to the cam shaft for the three types of cams described in Question 6.

Question 7

Describe the purpose of the cam displacement diagram and how it relates to the cam profile construction.

Question 8

Identify the parts of the spur gear shown in the drawing below.

Question 9

The total movement or displacement of a slider mechanism is called _________________________________________.

Question 10

List at least two functions of a gear. 59728_ch16_EOC_ptg01.indd 1 2/3/16 2:25 PM

Question 11

Draw a four-bar linkage and label the four links.

Question 12

What type of cam motion is best for smooth-running high- speed applications?

Question 13

List at least two uses for a slider crank mechanism.

Question 14

Explain why schematic symbols are used for linkage drawings.

Question 15

List three types of cam mechanisms.

Question 16

Define gear.

Question 17

Describe the function of a worm gear and worm.

Question 18

Describe the function of a bevel gear.

Question 19

Describe the function of a cam mechanism.

Question 20

The length of the displacement diagram for a drum cam is equal to _________________________________________.

Question 21

Given a spur gear with 54 teeth, diametral pitch of 6, and a pitch diameter of 9.000 in., calculate the following:

Question 22

What is the best material for use in the manufacture of plain bearings?

Question 23

Explain the difference between plain and roller element bearings.

Question 24

What is the gear ratio if the gear in Question 21 mates with a pinion having 18 teeth?

Question 25

Describe the difference between shielded and sealed bearings.