Clutches and Brakes

Question 1

WHat is the finction of a clutch

Answer 1

to engage or disengage a machine without starting or stopping the driver

Question 2

What are the two MAIN types of early clutches

Answer 2

POSITIVE CONTACT CLUTCHES
Square-jaw (dog)
spiral jaw

Question 3

What is the main advantage of friction clutches over the positive contact clutches

Answer 3

• can engage at with extreme loads at high speeds

- Transfer power smoothly with varying loads and speeds

Question 4

Name the three factors of the effectiveness a friction clutch depends on

Answer 4

Coefficient of friction between mating surfaces

Surface Area

Amount of force used

Question 5

What are the tow basic types of friction clutches and brakes

Answer 5

radial-contact pressure is applied to the peripheral of a drum or rim

axial-contact pressure is applied perpendicular to rotating shaft

Question 6

Common type of radial clutch

Answer 6

Band or strap brake

centrifugal clutch

Question 7

advantages of axial type clutches

Answer 7

Larger surface area

-can run dry or wet

Question 8

What is the advantage of a multiple disc clutch

Answer 8

• increased torque While keeping space limited
• more surface area
• lower weight

Question 9

What is the most common type of fluid clutch

Answer 9

Torque converter

Question 10

The_____clutch is an economical clutch for applications needing soft start and overload protection. It is used extensively in industry because of its simplicity and efficiency

Answer 10

h

Question 11

Which type of clutches and brakes are mainly for starting and stopping and are not suited for continuous slip operation

Answer 11

centrifugal clutch

Question 12

What is the flow charge of a dry fluid clutch

Answer 12

shot is dry pellets used instead of oil in fluid clutches, they can be steel shot.

The amount of shot used in the dry clutch is called the
FLOW CHARGE

Question 13

Which type of clutch uses non contacting NONFERROUS rotor (usually copper or aluminum) sandwiched between two magnetic disks mounted in a housing

Answer 13

eddy current clutch

Question 14

Unlike the eddy current clutch, the ____ _____ input and output does synchronize as long as its rated torque value is not exceeded

Answer 14

hysteresis clutch

Question 15

What is an over running clutch

Answer 15

mechanical device that allows rotation and torque to be transmitted in only ONE direction.

Question 16

How does a wrap spring over running clutch work

Answer 16

consists of three parts
input hub
output hub
helical wound spring

the spring in the middle is very tight and when it spins one way it will lock tighter and tighter preventing movement but going the other way loosens the spring and it can spin

Question 17

Most problems with friction type clutches usually can be identified by the excessive ______the clutch produces

Answer 17

heat

Question 18

over running

Answer 18

f

Question 19

INdexing

Answer 19

j

Question 20

backstopping

Answer 20

j

Question 21

the over running clutch types

Answer 21

pawl-and-ratchet
roller
sprag(or cam)
wrap spring

Question 22

What are backstop applications

Answer 22

j