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Learning Activities

Demonstrate knowledge of the concepts and components used in mechanical powertransmission.

Activity One: Answer all questions in the workbook

Activity Two: Dismantle, reverse, align gear teeth and re-assemble a worm andwormwheel unit.

Activity Three: Break and rejoin power transmission chain, inspect chain and sprocketsto determine wear.

Activity Four: Dismantle bearing units on the gearbox test rig, install gearbox, setupbearings on output shaft, align and tension chain drive and test run

gearbox..

Activity Five: Given additional gearbox components, detect faults in thecomponents, and identify probable causes.

Activity Six: Dumpy level exercise, levelling a bearing unit

Activity Seven: Rim and Face Dial Indicator alignment, align a water pump toan accuracy of 0.1mm.

Activity Eight: Laser Alignment, align the water pump to an accuracy of 0.05mm.

Activity Nine: Machine Levelling, level a lathe using an engineers level

Activity Ten: Machine Accuracy Test, carry out a standard machine accuracytest on a standard engine lathe.

Resources

Culley, Ron Fitting and Machining

General Edition Victoria, TAFE Publications (1988)

Jeffery, Dick Principles of Machine MaintenanceGeneral Edition Thomas Nelson Australia (1985)

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Review Questions - Gears

1. Identify the gear drives shown and answer the questions in the spaces opposite.

Type

Which gear is the pinion the left or the right gear?

Type

Which is the hand of the large gear?

Type

Identify the smaller gear

Type

Name the component on the left

Type

Name the lower component.

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2. Name the gear types in these transmissions.

A:

B:

3. Two helical gears are shown; the larger gear has 18 teeth and the smaller gear has 12teeth. What is the overall gear ratio?

4. If a wormwheel has 18 teeth and the worm is a 2 start, what is the overall gear ratio?

5. A worm reduction unit can have gears made from a variety of materials. If the worm ismade from hardened steel, what will the wormwheel normally be made of?

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6. This transmission unit can have the hand of drive changesfrom one side to other. Will the gear on the output shaft haveto be changed to one with an opposite helix angle if theother gear remain unchanged?

7. Shown are the teeth of gears in mesh with each other. There isa space between the gear. What is the name given to thisspace?

8. Two bevel gears are used to transmit motion between two shafts. The smaller gearrotates at 20 rpm and is used for a short time (5 minutes every hour). It cannot beenclosed in a gear case, because of cost. What would you use to lubricate it andabout what grade?

9. A wormwheel has been mounted incorrectly and is off-centre tothe worm. Bearing blue on the wormwheel gives the patternshown opposite. To which side of the reduction box will youadjust the wormwheel so that it is on centre with the worm tothe left or to the right?

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Review Questions - Chains

1. State two advantages of chain drives over belt drives.

2. Name the types of chain shown below:

3. What type of link is this and what is it used for ?

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4. What part of the chain is being removed bythe fitter?

5. A jockey or idler pulley is normally placed on what side of the chain drive?

6. The drawing shown a chain drive where thedriving pulley can be removed by adjustingscrews. Would you still have to provide a jockey oridler pulley to tension the chain?

Circle: Yes or No

7. What job is done by this device on a chain drive?

8. What are six causes of chain failure?

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9. Name three operating symptoms that indicate that a chain drive is not functioningproperly.

10. What does 'galling' mean when referring to chains?

11. Chain drives may need regular lubrication. List the various methods of lubrication anddiscuss their advantages/disadvantages.

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Review Questions V Belts

1. Name the types of belts shown and give one use for each type.

Name:

Use:

Name:

Use:

Name:

Use:

Name:

Use:

Name:

Use:

Name:

Use:

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2. Name two things you would check to make belts work more efficiently.

3. List the common faults in belt drives with respect to:

a. belt tracking

b. belt condition

c. belt tension

4. What do the following codings on vee belts mean?

B 2030

C 42

5. Describe a method of alignment and tensioning two V belt pulleys.

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6. List two (2) disadvantages of V belt drives.

(a)

(b)

7. List four (4) advantages of V belt drives.

(a)

(b)

(c)

(d)

8. Name two (2) advantages of toothed belts compared with other belt types.

(a)

(b)

9. List three (3) causes of belt failures and how they could be eliminated.

(a)

(b)

(c)

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10. What material should be used to make a guard and give the reason

why?

11. In the sketch below show how a V belt should sit in the pulley after tensioning and

prior to running.

12. Explain what is meant by the term creep.

13. Explain what is meant by the term matched set of belts.

14. Explain why it is important that belts used in multiple drives be a matched set?

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15. Explain the meaning of the term arc of contact.

16. Complete the following statement:

The greater the arc of contact _______________________________________________

17. Explain how the set-up shown below can be improved.

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18. On the diagram write in the sizes of a 'D' section belt.

19. Name three symptoms of poor belt condition.

20. What is the problem with a vee belt that squeals under load?

21. A drilling machine is driven by avee belt and speed variationsare obtained with stepped

pulleys. Using the informationfrom the sketch calculate thespeed at which the drillingmachine would run.

Answer:

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22. In a compound belt drive, a pulley on a motor revolving at 750 rpm drives a 400 mmdiameter pulley on a countershaft. A 100 mm diameter pulley on the samecountershaft drives a 300 mm diameter pulley on a machine.

If the speed of the machine is to be 100 rpm, find the diameter of the pulley for themotor.

Answer:

23. In use, this flat-belt has 4% slip. Calculate the rpm of the 400 mm diameter drivenpulley when in use.

Answer:

24. Calculate the diameter for the drive pulley if the driver-driven pulley diameter ratio is7:4

Answer:

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Activity V Belts

Select the correct V belts and pulleys to suit the conditions below.

1. An internal combustion engine operating at 1000 RPM is to transmit 40 kw of power toa rotary pump operating for 12 hours/day. The pump is to operate at 900 RPM.The shaft sizes for engine and pump are 45 mm and 40 mm respectively.

2. A cone crusher is to be driven by a 150 kw high torque electric motor. The motor speedis 1440 RPM and the crusher is to run at 850 RPM. The crusher operates 24 hours perday.

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3. A multiple stage piston pump is being driven by a 18 kw electric motor. The speed ofthe electric motor is 1440 RPM with the pump running at 220RPM. The pump runsapproximately 4 hours per day on an as needed basis.

4. A 6 kw 1450 RPM normal torque motor is to drive a single cylinder double actingcompressor at 850 RPM (15 RPM) on a continuous basis. Maximum pulley diameter

is limited to 200 mm, centre distance is limited to 300 mm.

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Review Questions Levelling

1. Explain why levelling of machinery is important.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

2. Define what is the levelling process.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

3. Name the three (3) main types of levels used.

(a) __________________________________________________

(b) __________________________________________________

(c) __________________________________________________

4. State four (4) common errors in using or setting up levelling equipment.

(a) __________________________________________________

(b) __________________________________________________

(c) __________________________________________________

(d) __________________________________________________

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Review Questions - Shaft Alignment

Coupling IdentificationFrom the information provided on the following pages, list the names of the followingcouplings and state which are lubricated.

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Coupling Identification Continued

1. Explain what is meant by the terms rigidand flexible couplings. Give an

example and use of each type of coupling.

________________________________________________________

________________________________________________________

________________________________________________________

2. List the advantages of using flexible couplings.

________________________________________________________

________________________________________________________

________________________________________________________

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3. List five (5) coupling types. Describe their operation, advantage and/or

disadvantages.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

4. What considerations should be observed when machining couplings?

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

5. Describe the correct procedure to be carried out when fitting a coupling to

a new unit.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

6. List the five (5) factors that must be known to select the correct type and

size of coupling.

(a) __________________________________________________

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(b) __________________________________________________

(c) __________________________________________________

(d) __________________________________________________

(e) __________________________________________________

7. List the advantages of taper-lock bushes used to fit couplings to their

respective shafts.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

8. What is a spacer coupling and where can they be used to advantage.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

9. What is meant by mechanically flexible and material flexible couplings?

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

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10. Explain this statement: Do couplings require lubricating?

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

11. List the causes of coupling failure and how it may be reduced.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

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Review Questions Shaft Alignment

1. List two (2) ways in which shafts can be misaligned. (A sketch may assist).

(a) __________________________________________________

(b) __________________________________________________

2. Explain why the centre line of the driver shaft should be below the centreline of the driven shaft when setting up a driver/driven unit.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

3. List three (3) standard methods used in industry for aligning shafts.

(a) __________________________________________________

(b) __________________________________________________

(c) __________________________________________________

4. Explain why is it important to mark each coupling before aligning shafts?

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

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5. Explain what is meant by the term soft foot.

________________________________________________________

________________________________________________________

________________________________________________________

6. Describe a suitable method that may be used to determine a soft foot

situation.

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

7. Explain why it is important to torque the holding down bolts?

________________________________________________________

________________________________________________________

________________________________________________________

________________________________________________________

8. List three (3) possible results of a coupling being mis-aligned.

(a) __________________________________________________

(b) __________________________________________________

(c) __________________________________________________