Operation Methods PC 2000-8

TRAINING CENTRE DEPT TRAINING CENTRE DEPT By:w@ldiman
Table of Contents
I. PRECAUTIONS FOR MACHINE OPERATION
1. Precautions before starting machine 10. Excessively long travel
operation 11. Traveling with rock pieces or dirt stuck to
2. Precautions for refueling track shoes
3. Precautions for greasing 12. Traveling with work equipment extended
4. Setting working mode
5. Inspection after the day’s work
III. MACHINE OPERATION
II. OPERATIONS TO BE AVOIDED 1. Bench forming
1. Impact digging by dropping the bucket 2. Loading dump trucks
2. Swing sweeping work with impact and 3. Gathering rocks and stones
moving large rocks by swing force 4. Bench root cutting work
3. Digging work using the bucket as a lever 5. Finishing work
4. Digging the cutting face sideways using
6. Rock unearthing work
swing force with no bucket teeth penetration
7. Edge digging operation
5. Operations when the undercarriage are not
8. Top end scraping work
stable
9. Twisting turn
6. Operations with machine’s rear end lifted
10. Traveling and changing the work site
7. Operations with hydraulic cylinders at their
stroke ends 11. Uphill traveling using the work equipment
8. Moving large rocks using the travel force 12. Downhill traveling
9. High-large speed travel over rock beds 13. Removing soil from the bucket
TRAINING CENTRE DEPT By:w@ldiman

I. PRECAUTIONS FOR
MACHINE OPERATION

1. Precautions before starting machine
I operation
(1) Inspection before starting the day’s work

Be sure to carry out a pre-work inspection and walk-around check before
starting the engine for the day’s work, following the instructions in the
Operation and Maintenance Manual.
CAUTION
If any abnormality is found during inspection, immediately take corrective action in accordance with
instructions in the operation and maintenance manual.
Operating the machine without proper corrective action can cause serious damage to the machine.
(2) Warm-up run

Before starting the machine, thoroughly warm up the engine, in
accordance with the instructions in the operation and maintenance
manual.
CAUTION
Operating the machine before the engine is thoroughly warmed up can shorten the service life of the
engine and hydraulic equipment.
If the machine is started while the hydraulic oil is still cold, it can cause a larger time lag in the work
equipment and traveling, which could result in serious accidents.

1. Precautions before starting machine
I operation
(3) Use clean cloth for checking oil.

I 2. Precautions for refueling
(1) Do not remove the strainer when refueling.

CAUTION
The strainer protects the fuel tank
against large pieces of dust. Even if
the fuel is clean, large pieces dust can
get in through the fuel port during
refilling, causing the fuel system to get
clogged. Therefore, do not remove the
NO G!
S SIN strainer when refilling with fuel.
TO
Strainer
(2) Use only fuel that is specified in the operation and maintenance
manual.
The use of fuel other than the specified one could cause serious
damage to the engine
(3) Do not use fuel that has been stored in a drum.
Fuel stored in a drum may contain a considerable amount of
impurities such as rust and water in the tank. Use of such fuel can
cause the fuel system to get clogged. It can also clog the fuel filter
prematurely.
I 3. Precautions for greasing
(1) Interval of greasing
Be sure to grease at the intervals specified in the operation and maintenance
manual.
CAUTION
Failure to grease as instructed can cause squeaking pins or scuffed bushing. If the
condition becomes worse, parts may need to be replaced, resulting in considerable
cost.
(2) How to grease

When greasing the pins, keep feeding until the old grease is pushed out
and the new grease begins coming out of the pin end. Wipe off the old
squeezed out grease.
CAUTION
The old grease contains a high
proportion of metallic dust generated
as the pins and bushings wear out.
Therefore, if the old grease is not
removed, it can cause the pins and
bushings to wear out prematurely.
Old grease Keep feeding grease in
until it is pushed out.

I 3. Precautions for greasing
(3) Be sure to wipe off the squeezed out grease.

I 4. Setting working mode
(1) Boom set at low pressure for normal operation
When the boom is set at low pressure, the hydraulic pressure is
automatically set to prevent the front end of the machine from lifting
unnecessarily and to achieve optimal bucket teeth force.
* When high pressure is set for the boom pressure, the front end of machine
rises above the ground more than necessary during operation. It causes
not only less riding comfort, but also heavier load imposed on the machine
body, which could result in damage to sections of the machine and crack
initiation.
When the boom is set at high pressure When the boom is set at low pressure
Low pressure
High pressure mode
mode
Escape
Simply setting the arm for a digging Even if the arm is set for a digging operation,
operation causes the front end of the the boom naturally escapes. So lifting of the
machine to lift significantly. front end of the machine is optimally deterred.

I 5. Inspection after the day’s work
(1) Removing dirt from the track frame (carrier roller)

Since the buildup of dirt around carrier rollers can cause the carrier rollers
not to turn easily, resulting in their partial wear, remove dirt as shown in the
following figures.
It should be noted that periodically removing dirt from the entire
undercarriage lessens the job of removing dirt from the carrier rollers after
work.
A buildup of dirt around the carrier rollers

can cause the track rollers not to turn Remove dirt from around the
easily, resulting in their partial wear. carrier rollers.

(2) Be sure to remove dirt from the track frame

(3) Checking bolts for looseness

Check the machine cover and the undercover for loosened bolts.
CAUTION
Loosened undercover mounting bolts can cause the undercover to come off, resulting
in deformation in the undercover.
(4) Checking work equipment and bucket for cracks

Check that the work equipment and bucket are not cracked.
Early detection of cracks is a key factor in the reduction of repair
costs.
Checking the boom

Checking the bucket Checking the arm
II. OPERATIONS TO BE AVOIDED

1. Impact digging by dropping
II the bucket
Operations to be Avoided
Excavation using the dropping speed of work equipment

II the bucket
Supplementary Explanation
If an attempt is made to dig rock using the dropping force of work equipment:
• Heavier load imposed on the frame and the machine body.
• Cracks in mounting bracket and tooth adapter by impact
loading.
<Shorter service life of the bucket> Mounting bracket

It causes a large distortion and deformation in
the mounting bracket of the bucket, resulting
in a shorter crack-resistant life.
In reality, however, impact digging as
discussed above is rarely practiced, so cracks
do not necessarily develop on the bucket
immediately after impact. But be careful not
to resort to such digging methods while
operating; otherwise, the crack-resistant life
of the bucket could be reduced to a quarter of
that of normal digging work. Tooth adapter

II the bucket
Operation to be Recommended
• When starting digging work, bring the bucket teeth

into contact with the rock surface slowly and gently
• Excavation taking cracks, fractures, and joints of
rocks into consideration

2. Swing sweeping work with impact and
II moving large rocks by swing force
Operation of hitting the bucket against a rock from a distance

using a swing operation

Operation of shoving a rock mass around with the

bucket as if using a broom with swinging force
* A rock mass here is defined as one exceeding

half of the bucket in size.

Operation of hitting the bucket against a rock from a distance or shoving a rock
mass around using a swing operation:
<Impact on boom>
The amount of distortion at the corner of the boom increases
caused by a distorted boom, and the crack-resistant life of the
boom is reduced to about half of that in normal digging work.
Boom Stress
Distribution Chart
Distortion centers on the corners

of the box that makes up a boom.

Operation of hitting the bucket against a rock from a distance or hauling a rock
mass using swing operation:
<Impact on work equipment pins>
Impulsive load increases by five times, and the load acts on
the connection between the arm and boom
Static load
When an impact is given,

Impulsive impulsive force 25 times the static
load force acts on the connection
between the boom and arm.

<Swing broom operation> Hold the

arm
1. Set the arm in a vertical position or closer to the vertical
machine body than the vertical position, and slowly
bring the side of the bucket into contact with the
rock and lower the bucket to the ground.
2. Level the road surface by an independent swing

operation. When the swing is released, slowly
remove the load with a BOOM RAISE lifting
operation and operate the swing.
Guide for
working on
rock mass by
swing broom
operation

<Hauling of rock mass>

• For rock mass, operate to pull in toward the front side as much
as
possible, using the work equipment.
(Simultaneous operation while traveling is disabled.)

3. Digging work using the bucket as
II a lever
Do not put the back of the bucket against a rock in the rear and dig out
a rock using the rear rock as a fulcrum.

II a lever
If you dig using the bucket as a lever:

• Force several times larger than the hydraulic force is
produced on the bucket teeth tips by the principle of
leverage.
• Possible cracks or damage to the bucket teeth or adapter
Do not put the back of the bucket

against a rock in the rear and dig out a
rock using the rear rock as a fulcrum.

II a lever
Operation to be recommended
Dig in such a way as to draw in, using the arm and bucket, to prevent
undue force from acting on the bucket with the safety valve in the
hydraulic system.

4. Digging the cutting face sideways using swing
II force with no bucket teeth penetration
When scraping off the

upper portion of a cutting
face, do not dig out a hard
rock without digging the
bucket teeth into a rock
while making a turn.

When scraping off the upper portion of a cutting face, if you dig out a hard rock
without digging the bucket teeth into the rock while making a turn:
<Boom Stress Distribution Chart when Digging
• The machine will be violently Sideways with the Bucket Corner>
A composite force of bending and torsion is
shaken, as the bucket teeth produced on the boom and a large amount of
slide down the rock surface, distortion will develop on it locally.
possibly causing cracks on Distortion centers
the work equipment and on the corners of
the box that
main frame. makes up a boom.
• Moreover, if the bucket hits a

rock protrusion while sliding
down, an excessively large
impulsive load will be
imposed on the work
equipment and main frame. ×
• Put the entire bucket teeth onto a rock and dig on the front side of
the machine as much as possible.
<Boom Stress Distribution Chart when

Digging with the Entire Bucket>
Distortion spread
across the boom
evenly
Digging
range within
30°

5. Operations when the undercarriage
II are not stable
Do not operate with unstable undercarriage condition.

II are not stable
If a machine is operated even though its track shoes are not in
steady contact with the ground:
Main frames are subjected to torsional deformation repeatedly,
and as a result, distortion centers on the swing circle mounting
portion and track frame mounting portion.
<Track Frame Stress Distribution Chart in an Unstable State>
Because these portions repeatedly undergo loads at

one point, the maximum distortion on them will
become approximately 1.3 times and reduce their
crack-resistant life to approximately one-third.
II are not stable
Pile up an earth mound in front of the undercarriage and climb up the

mound to provide machine stability as shown in the illustration below
before setting to work.
<Track Frame Stress Distribution
Chart in a Stable State>
Earth
mound
Ensure stability of the track frame footing
and carry out digging work right in a front
direction instead of an oblique direction; then
the load will be evenly distributed to the left
and right sides of the main frame.

6. Operations with machine’s rear end
II lifted
Digging work that causes the rear of an undercarriage to rise above

the ground
Slipping off

II lifted
If digging work that causes the rear of track shoes to lift above the ground is
forced:
(1) A significant composite force of the machine’s hydraulic

power and weight acts on the pins of the work
equipment and bucket, initiating cracks.
Excessive load

II lifted
If digging work that causes the rear of an undercarriage to rise above the
ground is forced:
(2) When the bucket teeth slip off a rock, the machine’s rear part
drops, hitting the ground hard. This will give a deep shock to
the counterweight, causing serious problems, including
deformation or cracks in the main frame and damage to the
swing circle bearings, etc.
Deformation and cracks in the main frame

Counterweight
Damage to swing circle bearing

II lifted
If digging work that causes the rear of an undercarriage to rise above the
ground is forced:
(3) When its raised rear portion drops, the roller guard or the
carrier roller’s flange can strike the track link hard and
break.

II lifted
Avoid forced digging work that can cause the machine to

lift. Instead, use a breaker or blasting.
When the machine is dropping, a load

in the horizontal direction is larger than
that in the back-and-forth direction of
the undercarriage. Therefore, use the
back-and-forth direction of the
undercarriage for the basic work
posture.

7. Operations with hydraulic cylinders at
II their stroke ends
Digging work with hydraulic cylinders kept to their stroke

end

If digging work is carried out as the hydraulic cylinders are operated to
their stroke end:
Shock is directly passed on to inner parts of the cylinder.
Damaged or broken pieces of the cylinder can cause
serious damage to the entire hydraulic circuit.
Shock to pins
Irons inside the cylinder’s

inner parts hit hard
against each other.
Shock to bucket teeth

When carrying out digging work, bring the hydraulic cylinder stroke
end to the front and provide relief with hydraulic pressure.

8. Moving large rocks using the travel
II force
Hauling rock mass using travel force

• Moving large rocks using the travel
II force
Digging using travel force

II force
If a rock mass is hauled over some distance or digging work is carried
out, both using travel force:
• If travel force is added during arm digging, the load on the tooth
tips increases to more than double the load during digging.
• Since travel shock and shoe slip impact are added, a higher-
than-expected load is imposed on the work equipment, pins and
frame.
A total of 100 tons or

more of arm digging
force and traction
45-ton arm force is imposed on
digging force the bucket tooth tips.
Force imposed on the bucket 57-ton traction * For PC800

tooth tips is 100 tons or force during
travel
more.
II force
• Hauling of a rock mass or digging using travel force is to be avoided,

because extremely strong force is produced during operation.
• Travel and work equipment are operated separately.
<Proper hauling of rock mass>

II 9. High-large speed travel over rock beds
High speed travel on rocky terrain

If you attempt to travel at the “Hi” speed range over rocky terrain:
The machine is tossed up accompanied by a big upward load
every time it climbs over a rough terrain. It could significantly
reduce the service life of the main frame, carrier and track rollers,
idler, sprocket, and links. When a machine climbs over
a block as illustrated in the
left figure, the load applied to
Travel at “Hi” Travel at “Lo” the machine’s main frame at
the “Hi” speed range is 1.5
times larger than at the “Lo”
speed range. If the machine
is subjected to this tossing-up
load repeatedly, the crack-
At the “Hi” speed resistant life of the main
range, the height frame is reduced
of falls increases. significantly.
Height of fall Height of fall

The reason for a higher load being applied at the “Hi” speed range than at the “Lo” speed range is that when a
machine climbs over a block, it runs through a long distance and the height of falls increases from that at “Lo”
speed range even with the same block, as illustrated below. Furthermore, a higher travel
speed also contributes to a greater collision impact.

To extend service life, be sure to travel on a rocky terrain at

the “Lo” speed range, turning the idler in the direction of
travel.
Use the “Hi” speed range only when traveling on sandy soil.
<Reason for traveling with the idler facing forward>

A shock-absorbing mechanism (recoil spring)
installed on the idler side serves to lessen shocks
to the machine when the front end of the track
shoes hits a rock bed or rock mass during travel.
Contrary to this, when you travel with the sprocket
side facing forward, and the machine hits a rock
bed or rock mass during travel, a heavy load is
imposed on the undercarriage, because no shock-
absorbing mechanism is provided. This can cause
a shorter service life for the machine.

II 10. Excessively long travel
If a machine is operated at the “Hi” speed range for more than

two hours continuously, it can cause oil leakage from within a
track roller due to damage to the oil seal.

II 10. Excessively long travel
If a machine runs at high speed for

long periods of time, heat is
generated inside the track rollers.
This can cause lubricating oil
contained in the track rollers to
inflate and leak from the floating
seal.
Floating seal
<Precautions when traveling for two hours or more>

Stop the machine once for every two hours of travel and let
it stand for 15 minutes.

11. Traveling with rock pieces or dirt stuck
II to track shoes
Traveling and turning with rock pieces or dirt stuck to track shoes

11. Traveling with rock pieces or dirt stuck
II to track shoes
• Damage to undercover or main frame

• At worst, this could cause damage to the hydraulic
component, resulting in serious accidents.
Extended Life Operation
• Check the machine frequently while at work to be sure

that no rock pieces or dirt are caught in or stuck to the
track shoes.
• In addition, check to see if there is someone or any
obstacle around the machine with mirrors before turning
or traveling.

12. Traveling with work equipment
II extended
Traveling with the work equipment extended can cause the bucket to
strike against a rock mass.

II extended
(1) If a bucket hits against a rock with the work equipment

extended, it can cause damage to the interior of the
cylinder and cracks around the work equipment pins.
* In particular, when a cylinder is kept at its

stroke end, this load further increases.

II extended
(2) If impact strength is exerted in the direction of

swinging, the swing’s mechanical brakes can be
dragged and damaged.
Mechanical brakes of the swing motor are automatically applied
approximately eight seconds after the work equipment control
lever is returned to the neutral position.
The swing’s
mechanical brakes

II extended
Extended Life Operation
Avoid traveling with the work equipment extended.

Basic posture for travel (when traveling on the flat ground)
Keep the arm vertical
Approx. 1 m above
the ground

III. MACHINE OPERATION

III 1. Bench forming
Create a bench quickly so that there is no waiting to load dump trucks.
When a dump truck comes, load the dump truck first. Build the bench
between loading dump trucks.
Drilled hole
<Work steps> Cutting face
(1) Dig out blasted rocks in the cutting face. Set a rock mass aside.
Scraping off
(2) Climb up on the scraped rock and dig out blasted rocks to increase the
stock. To prevent accidents caused by falling rocks when digging, provide Drilled hole
a safety fall beforehand where rocks are dumped. Cutting
face
Scraping off
(3) Gather the dropped rocks in the rock & stone chunk stockyard and create Safety hole
a bench.
Keep the top of the
bench horizontal.
Tamp the side
where dump trucks
enter at an angle
of 45 degrees to
prevent rock fall.
Working
bench
Dig a hole. Safety hole

III 1. Bench forming
(4) Shape the bench as follows: Design a bench shape that allows the most efficient work in accordance with field
conditions, including floor size, easy access for dump trucks, and height of the cutting face.
◆Shape of bench (example) ◆ Height of bench

Area to be
blasted
Area A
Digging
Rock and
stone Rock and
chuck stone Dump truck
stock area piling spot Idler body height
For scooping and loading on a dump truck,
high working efficiency is obtained by having
the swing at an angle of 30 - 120 degrees.
Scooping and Working bench
loading on Set the track shoes at right angles to the cutting face
dump truck to provide easy access to the cutting face.
Dump truck Moreover, always keep the idler on the side of the
cutting face to ensure instant operation before or
after traveling when a situation calls for.

III 2. Loading dump trucks
There are two methods of loading a dump truck as described below. Back-hoe loading offers a faster cycle time and
more efficient loading, as the inside of the dump truck body is highly visible.
A. Loading a dump truck B. Loading a dump truck

with the back hoe loading at the same level as
hydraulic excavator set the swing loading
at a level higher than hydraulic excavator
the dump truck
1. Back Hoe Loading (loading from a bench)

Load from the built bench.
<Work steps>
(1) To reduce shock to a dump truck body, scoop the smallest possible
amount of rocks and stones for the first fill.
(2) Swing in the loading direction and wait for the dump truck to come up
while activating the auto decelerator.
(3) When the dump truck comes up to the right spot, sound the horn to
stop the truck, and then start to dump. Dump at a lower level for the
first load to avoid shock to the dump truck.
(4) Continue to load until the dump truck becomes full. (For loading
sequence, see the right figure.)
Set the loading angle at 90° or lower.
(5) When the dump truck becomes full, press the heap surface lightly with
the bucket bottom.
(6) When a rock or stone is likely to fall from either side or the rear end of
the truck, push it into the truck body with the bucket teeth.
(7) When every step of loading is completed, blow the horn to signal the
dump truck driver to start up.
(8) After the dump truck has departed, remove rocks and stones strewn in
the truck approach path.

III 2. Loading dump trucks
2. Swing Loading (loading at the same level)
When there are fewer rock pieces on the bench and thus it has become difficult to operate back hoe loading,
perform loading at the same level as shown in the illustration below.
For the dump truck entry position,

set the swing angle at 90° or higher
when loading.
Digging Loading
An excessively small swing angle can cause the boom not to rise high enough in
the SWING + BOOM RAISE operation. So it cannot clear the dump truck body.
Thus, maintain a swing angle at 90° or higher as the standard.

III 3. Gathering rocks and stones
1. Gathering rocks and stones and loading dump trucks
While waiting for a dump truck to come back, gather rocks and stones at the loading bench to increase the stock.
While scraping off the cutting face and bench root cuttings and finishing the remaining cutting face, gather rocks
and stone. Large stock reduces loading time.
Uppermost portion
2. Scraping off rocks from the upper portion of the of cutting face
cutting face and gathering rocks and stones Scraping off rocks and Sub-working
stones toward the bench on which
<Work steps> machine poses a the machine
danger! climbs up
(1) Heighten the front part of the bench by (4) When rocks and stones
scraping off the cutting surface and are scraped off from
collecting rock pieces. the upper portion of the Scrape off while
(2) Drive the track shoe front up onto the cutting face toward the swinging.
heightened portion. machine, there is a Build a small
(3) Dig out a hole (safety hole) in front of the danger that dug-out working bench
rocks and stones can large enough for
track shoes beforehand where dug-out hit against the machine.
rocks and stones can be dumped. the machine to
Therefore, scrape climb up
Keep the machine at an angle If the angle exceeds 15°, the rocks off in a work
(approx. 10 to 15°) that allows machine’s swing movement Lowermost portion
the machine operator to view equipment + SWING
slows down and work
the upper part of the cutting
efficiency drops. Not only operation as illustrated of cutting face
face in a natural posture.
that, but there is also an below.
(5) When a cutting
increased danger of the
machine tipping over. face is too high to Scrape off the cutting face
reach the upper while waiting for a dump
portion from the truck to come.
bench, build a
small working Loading dump track
bench that allows
the machine to Sub-working bench
Safety hole climb up one step
at a time.
(6) When a dump Allow the machine to
Dig a hole here Heighten the front part go up and down. Working bench
truck comes,
beforehand of the working bench. handle loading
work first.

III 3. Gathering rocks and stones
<Point for scraping off earth in the upper portion of cutting face>
Dig the bucket teeth into the uppermost portion
If digging work is started in the middle portion and scrape off the cutting face. Then a larger
of a cutting face, working efficiency is low, work volume can be expected.
and, therefore, yield is low, too.
Safety hole
If the bucket teeth cannot reach the
uppermost portion, raise the height of the
working bench.
(1) When you start digging work in the middle portion of a cutting face, the bucket teeth do not easily dig into the
earth, so a large quantity of work cannot be done. In addition, for the same reason, the bucket teeth are likely
to slide off the cutting face, and that jolts the machine; or the teeth hit against a rock mass, causing a huge
stress to the work equipment and main frame.
(2) Basically, dig the bucket teeth into the uppermost portion of a cutting face for efficient operation and a larger
quantity of work. When you start work in the middle of portion of a cutting face, carry it out only when the
bucket teeth can dig well into the earth.

III 4. Bench root cutting work
1. Preparations for Work
<Work steps>
(1) Set the boom pressure at low pressure.
(2) Set the machine with respect to the cutting face as illustrated.
Portion of bench root cutting
Portion A
Small mound Idler side

of debris
(3) Scrape off portion A and build a mound of debris in front of the
track shoes.
The angle of the machine should be
(4) Driving the front of the track shoe up the mound provides machine such that an operator can easily see
stability and prevents felled rocks from hitting against the machine. the upper portion of the cutting
face.
The mound allows the machine to take a slight angle and
subsequently enables a machine operator to easily have a good
view of the upper portion of the cutting face. So it is good for work
safety.

2. Bench Root Cutting Work
<Work steps>
(1) Dig the bottom of the cutting face and rake out rocks and stones
toward the machine front.
(2) Digging work should concentrate on the bottom, and allow rocks
and stones left on the face to fall off freely.
(3) If only the upper portion is scraped off, and the bottom is left out,
loading with a wheel loader becomes difficult. Be careful to avoid
such an occurrence.
<Points of work>
Slowly operate the

bucket, searching for
joints or cracks.
(4) Dig the hard portion left at the bottom of the cutting face.
(5) Gather dug-out debris and place them in front of the machine.

3. Finishing Bench Root Cutting Work
<Work steps>
(1) Finish the bottom of the cutting face so that no debris, rocks, or stones
are left.
(The finished bottom must allow for a drilling machine to drill a hole
into it.)
(2) No wobbly rock or stone must be left on the cutting face.
(3) If a rock or stone which is too hard to dig out is found in the cutting
face, expose the surface of such a rock/stone so that a lateral hole can
be drilled into it for blasting.
<Points for digging out hard and large rock/stone>

Dig out a hard and ◆Point 1◆
big rock/stone by Upper surface of
removing earth on its hard and big Before digging, dig the bucket teeth well
sides. rock/stone into a rock in the upper portion of the
Digging cutting face. (If digging out from above is
found difficult, identify a joint and you can
start in the middle portion.)
◆Point 2◆
While digging, operate the bucket to the
DUMPING side, and maintain an angle
A basic digging pattern is to carry out digging
work in the following order: red dotted line that enables the bucket teeth to easily dig
level, blue, light blue, yellow, and brown. into a rock or stone.

III 5. Finishing Work
<Work steps>
Finish the remaining cutting face while loading a dump Termination of work
truck. At that time: Cutting face after scraping and digging:
No wobbly rock or stone must be left on the
(1) Be sure that no wobbly rock or stone is left. cutting face.
(2) When rock masses as large as 1 m or more are Ground surface:
found, gather them in one place separately from (1) Level off the surface as flatly as possible.
(2) Take care that the bottom of the cutting
other rocks. face does not rise at the base as shown by
the dotted lines. Or conversely avoid
Cutting face after scraping and digging making a downhill slope.
Be careful not to leave any wobbly
rocks or stones!
Bottom of cutting face:

Remove earth from here up to the drilled hole
Working so that no protrusion is left at the base of the
bench cutting face as shown by dotted lines.
Dig a hole.
Before terminating work, carry out the cutting face finishing <Points for finishing>
(1) When the bench root is partially left because it is too
work as illustrated below. hard to dig, blast that portion by toe hole blasting.
In such cases, clean the base of the bench root with a
swing sweeper so that a drilling machine can be brought
in.
When earth lumps and rocks are left scattered on the
ground, crush them with the bottom of a bucket. Track
shoes of a drilling machine are too small and not suitable
for such work.
(2) At the bottom of the cutting face, work such as drilling
and blasting powder charging is performed.
Therefore, finish the cutting face, so that no wobbly rock
or stone is left.
Working
bench
Bench root cutting
III 6. Rock unearthing work
Rake out wobbly rocks felled
Procedure for unearthing rocks for wheel loader by blasting from the upper
portion of the cutting face.
1. Scrape off wobbly rocks or stones
Cutting face
* For work steps and
precautions, see
Drilled hole Raking up Downward.
Blasted rocks
2. Building a working bench for scraping off the

upper portion of the cutting surface Rake out rocks from the middle
portion of the cutting face and build
<Work steps> a bench that allows a machine to
(1) Rake out rocks felled by blasting and build a small working climb up.
bench about 1 - 1.5 m high. * The working bench
(2) Drive the truck shoe front up onto the bench, rake out rocks in should be high
the upper portion and go up while building a bench. enough for the tip of
the arm to reach the
Rake out rocks from the upper surface of the
bottom of the cutting face cutting face when the
and drive the track shoe machine goes up.
front up onto the bench.
3. Scrape off the Upper Portion of the Cutting
Face and Gather Rocks and Stones !CAUTION!
<Work steps> Remove a rock mass
(1) Scrape rocks off from the uppermost part of the cutting face and as it is dangerous to
work on it or pave
dump them in a hole. When rocks are accumulated to some with small rocks of 30
extent, gather them at a swing angle of 90 - 180°. When you’re Safety hole cm or less to prevent
scraping off rocks, a back deeper than the drilled hole for the machine from
blasting must not be dug out. (The back blasting portion must slipping.
not be dug out.) Gather rocks left after scraping.
(2) Dig, so that no wobbly rocks or stones are left.
(3) When rock masses as large as 1 m or more are found, gather
them in one place.

III 6. Rock unearthing work
4. Bench Root Cutting
<Work steps>
(1) Dig the bottom of the cutting face as illustrated.
Gather dug-out rocks.
Gather dug-out rocks and stones toward the rear of the machine at
a swing angle of 90 - 180° .
(2) If the bottom is too hard to dig, go down to the ground level and
resume the same work from the ground level.
Cutting face after scraping and digging:

No wobbly rock or stone must be left on
the cutting face.
Ground surface:
5. Finishing (1) Level off the surface as flatly as possible.
(2) Take care so that the bottom of the cutting
Before terminating work, carry out the cutting face finishing work as face does not rise at the base as shown by
the dotted lines. Or conversely avoid making
illustrated below. a downhill slope.
Approx. 70°
Bottom of cutting face:

Remove earth from here up to the drilled hole so
that no protrusion is left at the base of the cutting
face as shown by
dotted lines

III 7. Edge digging operation
1. Preparation for work
<Work steps>
(1) Set the boom pressure at low pressure.
(2) Set the machine with respect to the cutting face as illustrated.
(3) Scrape off portion A and build a mound of debris in front of the
track shoes.
(4) Drive the track shoes up onto the small mound of debris and Idler
steady the footing.
2. Joint-utilized Digging Work

<Work steps>
(1) Dig the bucket teeth into a joint. (At that time, do not attempt to
forcibly raise the machine front.)
(2) In a slow machine operation of ARM DIGGING + BOOM RAISE,
dig out a rock or stone as if upending it.
Digging direction taking joint into account ①

A ② ③ B
• Digging which takes a joint into ④
consideration promises a large
Joint
quantity of work with low load on
the machine. Joint
GL
For A, start digging in the direction of (2).
Idler
For B, start digging in the direction of (4).
Always keep the idler turned in the forward
(3) In order to dig out a rock mass, provide a high working bench and
direction so that an operator can hastily
safety hole in front of the machine, and then carry out digging back up the machine in an emergency.
work as illustrated below.

III 8. Top end scraping work
1. Preparations for Work
<Work steps>
(1) Set the boom pressure at low pressure. (To prevent the
machine from lifting)
(2) Position the machine as far as possible from the edge of the
cutting
2. Downward Scraping Work

<Work steps>
(1) Scrape off the cutting face, dig out blasted rocks and stones,
and push them down through a complex machine operation of
BOOM LOWER + ARM DUMPING + BUCKET DUMPING.
(2) When the portion scraped downward becomes hard, dig with
a bucket and discharge earth at the bottom of the cutting face.

III 9. Twisting turn
<Work steps>
(1) Make a slight swing in the turning direction, hold the arm vertical, and
lower the bucket to the ground.
Arm to be held
vertically Turning direction
(2) Raise the end of the track shoes on the front idler side by 20 to 30 cm in a
BOOM LOWER operation.
Sprocket
Lift above the
ground 20 to 30
cm.
(3) While the machine is in position 2, make a twisting turn in complex
machine operation of a LEFT TRAVEL + LEFT SWING.
(Limit the angle of one twisting turn to less than 30°.)
(4) Lower the track shoes onto the ground in a BOOM RAISE operation.
CAUTION
If you attempt a sudden sharp twisting turn of the machine, a big travel
traction force can cause torsion to the work equipment as well as
serious damage to the undercarriage due to sand, dirt, or rock pieces
that have gotten caught up in it.

10. Traveling and changing
III the work site
1. Maintain proper travel posture for safety
(1) While traveling, hold the work equipment in a posture that
enables the operator to have good front visibility.
(2) Maintain the bucket approximately 1 m above the ground.
In a tight place or other places where traffic is busy, raise the Keep the arm
vertical.
bucket higher to ensure better front visibility.
On the other hand, on uphill and downhill slopes, lower the
bucket to a height approximately 40 to 50 cm from the ground
in order to prevent the machine from tipping over.
Approx. 1 m above
the ground
2. Watch for low grease on work equipment
after long-duration travel
Pins at various parts of the work equipment can run out of
grease after traveling for a long distance. When resuming
work, operate the work equipment slowly so that the pins will
be well greased.
3. Operation on a slope for a long time

When conducting work on a slope having a gradient of 10° or
more, travel back and forth every now and then to prevent
failure of the parking brake.

11. Uphill traveling using the work
III equipment
<Work steps>
(1) Start to climb up a slope. (6) Extend the arm again almost to its maximum to dig
(2) Lower the bucket to the slope surface and lift the machine’s front the bucket teeth into the slope.
end. (7) Continue to climb up in a TRAVEL + ARM
(3) Drive the front end of the track shoes up onto the end of the slope DIGGING + BOOM operation.
in a TRAVEL + ARM DIGGING + BOOM operation. (8) Extend the arm again almost to its maximum to dig
(4) Climb the slope as far up as possible in a TRAVEL operation, the bucket teeth into the slope.
then extend the arm almost to its maximum to dig the bucket (9) Continue to climb up in a TRAVEL + ARM
teeth into the slope. DIGGING + BOOM operation.
(5) Climb up the slope in a complex machine operation of TRAVEL + (10) Now the work of climbing up the slow comes to
ARM DIGGING + BOOM. an end.
* This way of climbing uphill is referred to as “Measured worm-like
climbing.”
CAUTION
• When climbing up a slope using this method, control travel by stepping on the pedals and do not
take your hands off the work equipment during climbing.
• Do not use this climbing method on snowy ground as the machine could slip.
• Do not climb on an exposed rock, since the machine can slip down the slope when the bucket teeth
are disengaged from the earth.
• Operate the machine quickly and accurately when using this method, since the machine is likely to
slip down during climbing. (Nos. 6 and 8)
• Try to have the track shoes slip for a short time, since they produce an earth stopper behind them,
and it serves to prevent the machine from sliding down. (Nos. 6 and 8)

III 12. Downhill traveling
<Work steps> (4) When arriving at a point just
before the slope bottom, lift
(1) Pull back the arm to a nearly the front end of the track
vertical position, maintain shoes in a BOOM LOWER
the bucket 10 to 20 cm operation.
above the ground, and make
Keep the bucket * If the machine keeps
a 180° turn. teeth upright. climbing down, the front end
of the track shoes get stuck in
the earth and the ground
(2) Extend the arm forward 20 surface around is ravaged.
to 30° away from a vertical
position and lower the (5) Climb down the slope in a
bucket to the ground. TRAVEL + ARM DIGGING
operation. When the front end
of the track shoes hits the
slope bottom, lower the front
end of the track shoes to the
ground in a BOOM RAISE
(3) Climb down the slope in the Do not operate operation.
“Lo” travel range of while the bucket
cylinder to its
leaving the bucket in contact stroke end.
with the ground. (6) Go down to the foot of the
slope in TRAVEL.
CAUTION
• Since the machine can tip over while making a turn, check that the machine is stable enough
before turning.
• When swinging the upper structure, hold the bucket at a low position and keep the bucket teeth
upright so that the bucket teeth can be instantly dug into the earth.
• Do not attempt to make a turn on snowy ground as the machine could slip.
• Likewise do not attempt to make a turn on an exposed rock either, since the machine could slip off
during turning.

13. Removing soil from the
III bucket
<Work steps> Hold the arm
(1) Run the engine at speed with the throttle partially nearly vertical.
opened.
(2) Set the machine in the following posture.
(3) Shake off dirt stuck inside the bucket in a BUCKET
DUMPING operation.
This BUCKET DUMPING operation should be limited to
4 to 5 times at a time. If the dirt is not removed by this
method, manually remove it using a shovel or the like.
BUCKET DUMPING operation
Operate the bucket cylinder to a

position approximately 100 mm before
its stroke end.
CAUTION
• Do not hit the tip of the bucket teeth hard against the solid ground to
shake off dirt stuck inside the bucket. Such practice can severely G !!
damage the machine. Instead, follow the steps below to remove dirt BAN
from within the bucket.
• Try to frequently remove dirt stuck inside the bucket.
If dirt is left stuck for a long time, it becomes more and more difficult
to remove.
• If dirt stuck inside the bucket is not even removed by the following
method, manually remove it using a shovel or the like.
• When you remove dirt from the bucket, dirt may fly off around the Hitting the bucket teeth tips hard against the
machine. Be sure that no one is around the machine before starting ground to remove dirt stuck inside the bucket is to
this work. be avoided.

END

Operation Methods PC 2000-8

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TRAINING CENTRE DEPT TRAINING CENTRE DEPT By:w@ldiman

TRAINING CENTRE DEPT By:w@ldiman

TRAINING CENTRE DEPT By:w@ldiman

(1) Inspection before starting the day’s work

(2) Warm-up run

TRAINING CENTRE DEPT By:w@ldiman

TRAINING CENTRE DEPT By:w@ldiman

(1) Do not remove the strainer when refueling.

(2) How to grease

TRAINING CENTRE DEPT By:w@ldiman

TRAINING CENTRE DEPT By:w@ldiman

TRAINING CENTRE DEPT By:w@ldiman

(1) Removing dirt from the track frame (carrier roller)

A buildup of dirt around the carrier rollers

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(2) Be sure to remove dirt from the track frame

TRAINING CENTRE DEPT By:w@ldiman

(3) Checking bolts for looseness

(4) Checking work equipment and bucket for cracks

Checking the boom

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Excavation using the dropping speed of work equipment

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<Shorter service life of the bucket> Mounting bracket

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• When starting digging work, bring the bucket teeth

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Operation of hitting the bucket against a rock from a distance

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Operation of shoving a rock mass around with the

* A rock mass here is defined as one exceeding

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Distortion centers on the corners

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When an impact is given,

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<Swing broom operation> Hold the

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TRAINING CENTRE DEPT By:w@ldiman

<Hauling of rock mass>

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If you dig using the bucket as a lever:

Do not put the back of the bucket

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TRAINING CENTRE DEPT By:w@ldiman

When scraping off the

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• Moreover, if the bucket hits a

<Boom Stress Distribution Chart when

TRAINING CENTRE DEPT By:w@ldiman

Do not operate with unstable undercarriage condition.

TRAINING CENTRE DEPT By:w@ldiman

Because these portions repeatedly undergo loads at

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TRAINING CENTRE DEPT By:w@ldiman

Digging work that causes the rear of an undercarriage to rise above

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(1) A significant composite force of the machine’s hydraulic