operating tips.pdf

8/18/2019 Operating Tips.pdf

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Caterpillar® Product Information

Operating Tips

Cat® 24H

®


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3/36

Index

3

Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4Differences — 24H versus 16H . . . . . . . . . . . . . . . . . . . . . . . . .5

MG/Truck Growth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Static Compaction Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7General Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Differential Lock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8Wheel Lean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Moldboard Positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10

Down Pressure Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12Cutting Edge Sharpness . . . . . . . . . . . . . . . . . . . . . . . . . . . .12Cutting Edge Thickness . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

Drawbar Positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14Spoil Pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16Haul Road Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18

Spreading Dumped Material . . . . . . . . . . . . . . . . . . . . . . . . . .20Shovel Pad . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22Narrow Corridor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23Ripper Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24Roading the Grader . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25Ditching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26

Moldboard Angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28Drawbar, Moldboard, Circle Protection . . . . . . . . . . . . . . . . . .30Operating Speeds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31Machine Controls — Pedals . . . . . . . . . . . . . . . . . . . . . . . . . .32Monitoring System — Torque Converter . . . . . . . . . . . . . . . . .33Machine Controls — Speed Control . . . . . . . . . . . . . . . . . . . .34

Cat 24H


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4

Specifications

Cat 24H

This handbook explains key features, specifications andoperating techniques of the Caterpillar 24H and 16H MotorGraders. Both machines, and the techniques described herein,

are intended for use primarily in mining applications.24H 16H

Operating Weight 64 863 kg 27 578 kg143,000 lb 60,800 lb

Engine Cat 3412E w/HEUI Cat 3406CHorsepower 373 kW @ 2000 rpm 205 kW @ 1850 rpmNet Peak Torque 2397 kW @ 1300 rpm 1376 Nm @ 1200 rpmTorque Rise 30% 30%

Transmission Cat Power Shift Cat Power Shift6F/3R 8F/8R

Moldboard 7315 mm x 1067 mm x 50 mm 4877 mm x 787 mm x 25 mm24' x 42" x 2" 16' x 31" x 1"

Tires 29.5R29 18.00x25 (12PR)Optional: 23.5R25

Fuel Tank 1207 L 492 LRefill Capacity 318 g 130 g

Speed Range 3.2 - 37.7 kph 3.9 - 44.6 kph

Wheel Base 10 230 mm 7000 mm33'7" 22'10"


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5

Operator

• 24H is much larger grader — less operator “feel”• 48% more cutting edge downpressure• cutting edge wear characteristics

Transmission• 24H has Torque Converter versus Direct Drive• Autoshift• Speed Control• Transmission neutralizer pedal versus inching pedal

Drawbar/Circle/Moldboard• 24H uses dual circle drive motors• No blade linkage on the 24H, less blade positioning

Machine Controls• 24H uses pedals, electronic versus mechanical linkage• Common PPPC hydraulic valves

Cat 24H

Differences — 24H versus 16H


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6

MG/Truck Growth

Cat 24H

MG/Truck Growth

0

50

100

150

200

250

300

350

400

1975 1980 1985 1990 1995 2000

T o n

s

24H 16H 16G OHT

777

777

785

789

793

797

• Trucks have grown from a 75 ton truck in 1975 to a 360 ton

truck today.• The evolution of larger trucks has driven increases in:• - Travel speeds• - Haul road width• - Haul road compaction• - Depth of ruts

• - Moisture pumping• The weight and horsepower of the 16G/H remainedrelatively unchanged as trucks grew, which means:

• - additional motor grader capacity is required, or• - more production is needed from existing motor

grader fleet

Note: Between 1975 and 1980, the 777 grew from a 75 ton truck toa 100 ton truck.


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Static Compaction Areas

7

0

2000

4000

6000

8000

1000012000

14000

16000

18000

777 785 789 793 797

S q .

I n c h e

s

91%107%

269%

44%

Compaction Areas

Percentage increase in static compaction area

• As truck size increases, static compaction areas increase

dramatically.

Cat 24H


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8

General Tips

Cat 24H

• Always have the grader in the proper setup before beginning

the working pass.• Trucks must use caution when straddling windrows generatedby the 24H. The windrow will be taller than those generatedby 16G/H’s.

Differential Lock• When engine speed is above 1300 rpm, the 24H will operate

in Direct Drive. If engine speed is below 1300 rpm, the graderwill operate in Torque Converter Drive. Load factors caninfluence the transition point. When operating in torqueconverter drive for sustained periods of time, transmissionoil temperature will increase.

• Always unlock the differential before turning.• Never lock the differential when tandem tires are spinning.

Reduce engine speed until tandems stop spinning, then lockthe differential.


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Keep adequate distance between windrow and insideof tire to prevent sidewall damage from sharp rocks.

General Tips

9

Wheel Lean

• Use wheel lean to counteract material side draft forces.Lean top of wheels toward the heel of the moldboard.• Combine articulation and wheel lean when turning around

to reduce turning radius from 104' (straight frame) to 39'11".This method eliminates the need for 3-point turn-arounds, apossible safety hazard on busy haul roads. Note: Using max.

wheel lean and a full turn can create interference with thesteering stops and the front axle.• Wheels leaned in the wrong direction during a turn-around

cause the tires to roll over onto the sidewalls of the tire,potentially damaging the tire and increasing turning radius.

Cat 24H


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Moldboard Positioning

11

• Tip the moldboard forward to cut hard packed material and

tip it back for processing, carrying, and combing out oversizedrock. Be careful when tipping back: damage can occur to thecutting edge support or pivot area.

• Turn on blade cushion system when cutting.• Use the thinnest cutting edge that material and conditions

will allow. This will improve material rolling action and

increase moldboard downforces. It will also require lesshorsepower to power the grader through the cut, improvingboth fuel consumption and tire wear.

Cat 24H


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12

Down Pressure Tips

Cat 24H

0

50

100

150

200

250

16H25 mm

24H28 mm

24H45 mm

24H60 mm

24H75 mm

Moldboard Down Pressure

Max. Moldboard Down PressurePSI

Cutting Edge Sharpness

• This is the single most important factor for materialpenetration and material action on the moldboard.• Most complaints of poor material action on the moldboard

are due to a dull cutting edge and incorrect moldboardposition.

• The operator is responsible for keeping the edge sharp.

To sharpen the edge, roll the blade back when mixingmaterial or sweeping the roads.• For optimum penetration when cutting, tip the moldboard

forward.• A sharp cutting edge will reduce the amount of rimpull

required to push the blade through the cut, reducing overall

operating costs.


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Down Pressure Tips

13Cat 24H

Cutting Edge Thickness

• The thickness of the cutting edge can have a large impacton $/hr. It is important to understand that as you increasethe cutting edge thickness (28 mm to 45 mm, to 60 mm to75 mm), that you are reducing the maximum amount ofmoldboard down pressure per square inch of cutting edge.The maximum down pressure of the grader remainsconstant but that force is spread over a larger surface area.

• Therefore, a thicker edge requires the operator to use moredown pressure to penetrate and cut material. Use ofexcessive down pressure causes many negative results:

• - increases rimpull requirements — burning more fuel,• - increases frequency of tire slip — accelerating tire wear,• - increase forces on the frame — reducing component life,

• - sends higher torque loads through the drive line —reducing component life,• - builds excessive heat on the cutting edge — which can

exceed heat treat tolerances.


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14

Drawbar Positioning

Cat 24H

• When processing material, shift the drawbar in the direction

of the moldboard heel. This allows steep moldboard angleswhile depositing material outside the tandem tires.• Slight adjustments to moldboard sideshift and drawbar

centershift can improve visibility to critical areas,especially tires.

• Use caution when making drawbar adjustments during

a pass. It can have a large effect on the cross slope.

Fig. 1

Fig. 2

Material dischargingto the left and drawbarshifted left


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Fig. 3When drawbar shifted to the left,

left cylinder is vertical, right cylinder is shifted.

Drawbar Positioning

15

View from the operator’s station showing proper setup todischarge material to the left side of the grader. Note theposition of the lift cylinders. This indicates the drawbar isshifted to the left, widening pass coverage and improvingvisibility to the toe and heel of the moldboard.

Cat 24H


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16

Spoil Pads

Cat 24H

• Divide the work area into sections. Work and complete one

section at a time to quickly remove the windrowed materialfrom the truck turn-around area.• Remove large rocks from a windrow before moving it across

the truck turn-around area.• Use caution when straddling large rocks to prevent machine

damage.

• If the TTT has generated enough loose material near the berm,it is not necessary to pull material from the dump berm.


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Spoil Pads

17

• An alternate technique is to begin generating the windrow

approximately 2 pass lengths from your inside perimeter.The first 2 passes will be away from the dump berm. Thenbegin moving the material toward the dump berm.

• Note: With any technique, it is important to minimize thetime a windrow of material is left in the truck turn-aroundarea. This will reduce the number of times a truck will cross

the windrow, thus reducing scattering of material and thechance of truck tire damage.

Cat 24H


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18

Haul Road Maintenance

Cat 24H

• Pull enough material from the berms to build up the road

surface and fill in low areas.• Leave rocks smaller than 2” in diameter on the road surfaceto provide additional traction to trucks when the roadsurface is wet.

• Comb the larger rocks off the road surface. These can slowthe flow of water in the ditches and retard erosion.


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Haul Road Maintenance

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• Always begin road maintenance at one end of the working

section.• The windrow will serve as an indicator to the trucks that agrader is ahead. When possible, make the initial pass in thesame direction as truck traffic, to avoid maneuvering aroundoncoming truck traffic. This technique prevents leavingbends in the windrow which could cause safety hazards

and production inefficiencies.

Cat 24H


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20

Spreading Dumped Material

Cat 24H

• Material should be dumped on the road centerline in evenly

spaced piles to achieve desired coverage depth. The roadwidth and desired coverage depth will determine thedistance between piles.

• Sideshift the moldboard towards the toe to maximizeamount of material that can be pulled from the pile(s).

• Position grader in crab mode, with the front tires away from

the piles and the rear articulated so that the tandems arerunning on the material being spread.


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Spreading Dumped Material

21

• Work in the direction of traffic when pulling material from

the piles. This will help keep truck traffic moving, preventinghaul road congestion.• Spread material to the desired depth, and if possible,

spread the material in both directions to ensure evenmaterial distribution.

Cat 24H


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22

Shovel Pad

Cat 24H

• Break working area into sections to reduce the time a

windrow is in the work area. If possible keep a lane openfor haul trucks.


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Narrow Corridor

23

• Use techniques described in the haul road maintenance

section.• Use articulation when processing the windrows to givetrucks better visibility around the grader and more roomto pass.

Cat 24H


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24

Ripper Use

Cat 24H

• Rip in 1st gear only and begin at low throttle.

• Proper use of the ripper (cutting high spots and fracturinghard packed material) can help lengthen moldboard cuttingedge life.

• Use the ripper indicator gauge in the cab to determinethe depth of penetration. This will allow the operator toconcentrate on the conditions in front of the grader.


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Roading the Grader

25

• Sideshift the drawbar to the right and circle the moldboard

until it is inside the width of the grader. Use caution in thisposition so that the moldboard does not contact the stepsor the tires.

• NEVER articulate the grader toward the heel with themoldboard and drawbar in this position.

Cat 24H


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Ditching

Cat 24H

1st Pass

• Shift the drawbar toward the heel of the moldboard andaway from the ditch.• Tip the moldboard back so the top is behind the cutting edge.• This position prevents drawbar and lift cylinder mount

contact, and allows the moldboard to be carried at anextremely steep angle while providing adequate clearance

from the tandem tires.• Use caution in this position to prevent heel of themoldboard from contacting the steps and the toe of themoldboard from contacting the front tires.

• Raise the moldboard heel to maximize ditch depth andreduce the width of the ditch foreslope. This steep angle

will help move the material up and out of the ditch bottomand deposit it between the tandems.


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Ditching

27

2nd Pass (Shoulder Cleanup)

• Articulate the rear of the grader and position the tandemtires toward the ditch and front tires away from thewindrow (Crab Mode). This position keeps the front ofthe machine from slipping into the ditch, allows steepermoldboard angles preventing material from spilling backinto the ditch, and leaves a clean, sharp shoulder.

• Material will be deposited outside the tandem tires towardthe road centerline.• Lean top of the tires away from the ditch to counteract

the side draft and prevent a rock in the windrow frompotentially cutting the tire sidewalls.

3rd Pass• Straddle the windrow and move the material as far as

possible toward the road centerline.

Cat 24H


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28

Moldboard Angle

Cat 24H

• Pass coverage is reduced as the moldboard angle increases.

• Deposit material at least 18” from the tandem tires toprevent potential sidewall damage from sharp rocks in thewindrow.

24'

@ 0° Angle

20.9'

@ 30° Angle

Effect of Moldboard Angle on Pass Coverage


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Moldboard Angle

29

Pass Coverage

0.00

5.00

10.00

15.00

20.00

25.00

Blade Angle (degrees)

C o v e r a

g e ( f t )

24H

16H

16H Min.

24H Min.

10 15 20 25 30 35 40 45 50

Steeper Moldboard Angles

• reduce rimpull requirements• improve material movement across moldboard• allow processing of large windrows

Cat 24H


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30

Drawbar, Moldboard, Circle Protection

Cat 24H

Blade Lift Accumulators:

• Standard equipment on 16H and 24H graders.• Protects the DMC area from damage due to vertical shockloads by allowing the moldboard rise over imbedded rocksin the haul road surface.

• The blade lift accumulators should always be switched“ON” during earthmoving applications.

Circle Drive Slip Clutch:• Standard equipment on all H-Series motor graders.• Protects the DMC area from damage due to horizontal

shock loads.• Can be adjusted to match operating conditions.

Compressednitrogen

Piston in

unloaded

Piston inloaded

Hydraulic


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Operating Speeds

31

Operperating Speedsting Speeds

16H 24H Application

2.4

3.4

4.6

6.7

10.1

14.1

27.7

(mph) (mph)

19.1

2.0

26.5

15.1

8.1

5.3

3.1

Sloping,Ditching

Earthmoving,Balancing Material

Road Maintenance

Travel

Ripping

Earthmoving Speeds:

• Typical applications are performed under 6 mph.• The 16H has four forward speeds under 6 mph, the 24H hasthree forward speeds under 6 mph.

• In many situations the 24H should be operated at one gearlower than 16H because of differences in the gear ratios.

Cat 24H


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Monitoring System — Torque Converter

33

• 24H is the only Cat motor grader model with a torque converter

• Indicator Light will illuminate when the grader is inconverter drive and not direct drive• Monitor the torque converter oil temperature when

operating in converter drive• Can be engaged manually by depressing the transmission

neutralizer pedal half way OR …

• Will be engaged automatically if the engine RPM dropsbelow 1500

Cat 24H

Torque ConverterOil Temperature

Indicator Light


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34

Machine Controls — Speed Control

Cat 24H

• Turn on Speed Control — Press top half of switch

• When desired speed is reached, press the top half of theSET/RESUME switch• System will maintain a constant SPEED • Can be adjusted faster or slower in 1.6 kph (1 mph)

increments via the Accelerate/Decelerate switch• Depressing the service brake pedal will disengage the

speed control system• To resume operator’s preset speed — press the bottom halfof the Set/Resume switch

• System is active in gears 2F-6F only

On/OffSwitch

Set/ResumeAccelerate/Decelerate


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Notes

35Cat 24H


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The information contained herein may contain unverified analysis and facts observed

by various Caterpillar or Dealer employees. Effort has been made to provide reliable

results regarding any information comparing Caterpillar built and competitive

machines. Effort has been made to use the latest available specifications and other

materials in the full understanding that these are subject to change without notice.

Any reproduction of this release without the foregoing explanation is prohibited.

TEJB6093 ®

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