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OPERATING
In general, for safety reasons on work sites, excavators
should only be used by fully trained operators, who are familiar
with the technical
and safety aspects of this type of machinery.
However, there
are cases, on DIY hires for example, where this is not the case,
and the hints below may be of use. These should
be read
in conjunction with the safety instructions provided by the
manufacturer and/or hirer of the machine and are by no means intended
as a
full set of instructions and guidelines.
Hints:
- Safety. Always observe site and machine safety
rules, which should include:
a. MAINTENANCE. Carry out all service checks and adjustments
each day and ensure the excavator is in safe condition.
(See Daily
Service
Checks)
b. THINK! Before you start operating the excavator,
whilst it is warming-up, consider the safety issues,
for you, your
fellow
workers, and the
general public.
c. NEVER get off an excavator without
- Lowering bucket (and blade, where fitted) to
the ground.
- Stopping engine and/or disengaging safety
lever.
d. NEVER work
- With you or other workers under the boom, dipper
or bucket, or in the operating arc of
the machine. Keep co-workers and
spectators clear at all times.
- Under the excavator when
it is jacked up on the arm and dozer.
e.NEVER use the excavator
as a crane.
f. ALWAYS ensure you are
aware of the location of overhead, or underground
services – gas,
electricity, water, drainage, and telecommunications.
g. TAILSWING. Be aware that the counterweight,
at the rear of your excavator, can swing out wider than
your tracks.
Keep co-workers
and spectators
out of the tail swing area.
h. PASSENGERS. Do not allow anyone to
ride on the machine as a passenger. On all be the very
largest of excavators,
there
is only
one seat
provided – for
the operator.
i. CHILDREN. Do not allow children to
operate the excavator.
 Stability. Always remember that the stability
of an excavator is variable, both in terms of dynamics and site
conditions,
and depends on:
a. Ground Conditions. Be aware that the ground may not give
sufficient support for your excavator, particularly at
reach. (With heavy,
long-reach machines,
even roadways may give way.)
b. Reach. The higher, or further out you reach with the
excavator arm, the greater the risk of the machine tipping
over, or the
ground giving
way.
c. Speed. The faster you track, slew, or swing the dipper
arm, the greater the risk of the machine tipping over.
d. Position. Excavators will normally have maximum stability
when working in line with the tracks, and minimum stability
when digging across the
tracks.
e. Weight. Increased weight on the end of the digging arm – be
it a bucket or attachment – will reduce the machines
stability. Be aware of your machines safe working weights,
and never use
overrated buckets
or attachments
as they
can damage the machine and destabilise it.
f. Gradients. Take care when operating on gradients, and
avoid crossing the slope or making sharp turns. Travel
up and down
slopes with the bucket
close
to the
ground.
g. Travelling. Always fold the digging arm in towards the
excavator when tracking. Never travel with the arm fully
raised or extended
at full
reach.
- Speed. Until you are familiar with a particular machine
(or bucket/attachment) do not operate at maximum engine speed.
Operate smoothly and gradually
increase engine speed and power.
- Digging. For stability always try to dig over the track
sprockets, in line with the tracks. On mini excavators, this
will be with
the dozer blade
to the
rear (this will also avoid damage to the blade and dipper ram),
and if possible the blade should pushed down until the rear
of the track is
about 25mm off
the ground.
- Controls. Most excavators – whatever
size – have
a very similar control layout for the main digging function
(click here to see diagram):
a. Training: We recommend these notes are used in addition
to, rather than instead of, relevant operator training.
b. Up & Down: Lift is mainly* influenced by the boom
ram(s), are normally controlled by pulling back (up)
or pushing forward
(down) the right hand joystick/lever.
c. In & Out: Reach is mainly* influenced by the dipper
ram, which is normally controlled by pulling back (in)
or pushing forward (out)
the left hand joystick/lever.
d. Curl & Dump: The emptying or filling of the bucket
is mainly* influenced by the bucket ram, which is controlled
by
pressing left
(curl/fill) or pressing
right (dump/empty) the right hand joystick/lever.
e. Slew/Swing: To rotate the upper structure of the machine
on the track frame, press the left hand control lever
in the required
direction; left
to slew left/anti-clockwise,
or right to slew right/clockwise.
f. Tracking: This may be via levers and/or foot pedals
in front of the operator. When the machine is facing
forwards (i.e.
the track drive sprockets
are at
the rear) the right and left tracking levers control
the right and left tracks respectively.
However, this stays the same, no matter which way the
upper structure is slewed, and therefore takes a little
getting used
to!
g. Other: There are other controls within the cab. On smaller
machines, there is often a dozer blade, which is raised
or lowered by a lever in
the cab.
There may also be foot pedals controlling the auxiliary
(i.e. attachment) hydraulics
and, in the case of smaller machines with boom offset,
the swing of the arm about the upper structure of the machine.
There
may
also be an engine
throttle
control,
although on newer and/or larger machines, this is often
computerised with options for performance modes.
- Spoil. Place spoil away from the sides of the trench, and
try to keep tracks free from spoil and debris.
- Dozing. Use the dozer blade carefully and sparingly. Excessive
use and deep cuts using the dozer will reduce undercarriage
life.
- Attachments. The following guidelines are
useful in relation to ancillary attachments.
a. Size/Rating. Never use attachments that are overrated
(i.e. too large or powerful) for your machine. Not only
can they
damage you machine (e.g.
overrated hammers
can bend and break dippers and rams), they can also
severely destabilise the excavator, both through weight, and
dynamic
forces.
b. Collision. Be aware that attachments may collide with
parts of the machine that ordinary buckets will clear.
This may
include the operator
cab, so
operate slowly at first and pay full attention. Be
particularly careful when first
operating an attachment.
c. Weight. Be aware that attachments may be heavier
than standard buckets, although they should never exceed
your
machines safe
working capability.
If in doubt check.
They may cause a decrease in stability so operate slowly
at first and pay full attention. Be particularly careful
when first
operating
an attachment.
d. Work. Be aware that there are additional considerations
with attachments that can pick up objects:
- It may be possible to attempt to pick up objects
that are heavy enough to overload and de-stabilise
the excavator.
This
should be avoided.
- The objects you are attempting to pick up may
not be stable. Try to avoid picking up objects
that may
swing, slip
or overbalance,
as this
can
de-stabilise
the excavator and cause danger to other site
workers.
- Side Swiping. NEVER use the excavator arm
to "side swipe".
This can cause serious damage to both the arm and also the
bucket/attachment, in
extreme cases the dipper arm will be destroyed.
MAINTENANCE & SERVICING
For full requirements, please check
the manufacturers Operators Manual, specific to your excavator.
As a rough guide, the following
daily checks
should be
made:
Daily Checks:
- Check engine oil level and top up if necessary.
- Check radiator coolant level and top up if necessary.
- Check hydraulic oil level and top up if necessary.
- Check fuel level and top up if necessary.
- Check battery(s) electrolyte level and top up if necessary.
- Check fan & alternator drive belt tension and adjust if
necessary.
- Check tracks are not clogged with dried or frozen
mud and debris.
- Check track adjustment tension if necessary.
- Grease all points on the excavator arm, and attachment
(and also on the slew ring assembly approximately every
50 hours),
bearing in
mind:
a. Use correct grease. If you have a very high temperature
or high impact job, you will need a better grade
of grease. Work
in very
wet weather
or partial
submersion of water may cause wash out of standard
grease – use
high washout resistant grease.
b. The dipper end and attachment may need to be greased
more regularly than one a day under conditions were they
are exposed
to water, sand,
salt or
fine dust.
- In hot and dusty conditions, check the air filter element(s) and clean if necessary.
- Check bucket/attachment pins are properly secured
with the correct retaining clips or bolts. Unsecured
pins can
easily come
adrift causing
damage to the
bucket/attachment and the excavator, as well
as posing a safety issue.
KNOW
YOUR MACHINE
For almost all parts, spares, buckets and attachments, it
is vital that you know which excavator you have. This advice may
appear to be patronising,
but it is
common for us to receive enquiries where the only information the owner
can
offer is that "it’s an orange digger" or "it’s
got a Kubota engine". Lots of manufacturers use orange paint,
and equally, there are a lot (other than just Kubota) who fit Kubota
engines.
Whether you are talking to us, a main dealer, manufacturer,
or reporting
the theft of a machine (and hoping to stand some chance of getting
it recovered) to the Police, you at least need to know:
- Make of Machine, e.g. Samsung
- Full model of excavator, e.g. SE210-3. N.B. This is not necessarily
as is written on the side of the excavators engine cover, so
check also on the
machine
serial number plate (normally located near the cab/boom at
the front of the chassis).
- Serial number, again, this can be found, like the model information,
on the serial number plate. There may be significant component
changes on the
same model
of excavator, built at different times.
- Country of manufacture. Most large manufacturers have at least
two factories – one
in Europe and another outside the EU - and in some instances,
the excavators may vary either on a component level, or in
some cases the whole machine.
Machines which are non-EU specification and are imported second-hand
into the EU are
often referred to as grey imports, and may, in some cases be
difficult to obtain spares
for.
BUCKETS
There is often a degree of confusion, and even ignorance,
where buckets are concerned, and yet this is quite literally the
sharp-end
of the
whole machine,
where all
the work is done.
People spend tens, or even hundreds of thousands of pounds on the
latest excavator, and then negate any advantages gained by fitting
them with
old, or incorrectly
specified buckets. Whether they fit the same old, ‘patched-up
antique’ buckets
that have been knocking around their plant yard for years, or buy
the cheapest new bucket they can find, irrespective of build and
quality, the net result
is that their machine will under perform.
Buying and Using:
At DIGBITS, we understand that getting the right buckets, and using them correctly
is vital. Having the right tool for the job maximises efficiency
and prevents
damage.
There are a few general bucket rules which apply to all excavators:
- Cycle Times: Bear in mind that the fastest cycle times
(i.e. the time taken to dig a full bucket load, tip it into
a truck/skip/hopper
and
return to the
dig position) are NOT necessarily achieved with the widest
or largest capacity bucket. This is especially true in harder
ground
conditions.
- Stability: It is not generally advisable to exceed the
maximum bucket width declared in your machines specifications.
Any
modifications to
the machine
work equipment – boom or dipper extensions, quick-hitches etc. – will
tend to de-rate the overall machine stability.
- Narrow Digging: On most machines, the limiting factor
for bucket width will be the width of the bucket linkage
and pins.
It is possible
to build
taller narrower
buckets, though these may have a reduced breakout capability,
the potential for collisions with parts of the excavator
with normal
buckets would
not reach, and
cannot dig deeper than the bucket itself.
- Digging Buckets: Keep the teeth in good condition, and
try to catch any wear before it becomes critical (see Repairs)
to avoid
expense.
Do not be
tempted to use for heavy duty, demolition, rock or quarry
applications – sadly
most customers who buy our XHD buckets have already scrapped
a perfectly good GP or HD buckets on these jobs.
- Ditching Buckets: These are designed for re-handling and
levelling of soil, so expect them to dig compact or rocky
ground. The width
of these
buckets, and their lighter construction means it is worth
avoiding catching the outer
edges
on objects which are firmly fixed into the ground (e.g. large
rocks or manholes) as they will bend. We are often asked
why we don’t build them heavier – the
answer is that you would end up putting a ‘corskcrew’ type
bend into your dipper arm!
- XHD Buckets: These can be used on any application, from
digging soil to digging and loading rocks in a quarry. Refer
also to
the notes on
Digging Buckets and Cycle Times.
- Price. If you’ve read the notes above, you won’t be surprised
to hear that with buckets – as with many things in life – the cheapest
is rarely the best choice. We’ve all seen the sob stories, in the papers,
on the TV (on shows like Watchdog) of people who’ve employed the cheapest
builder, or gone on the cheapest holiday, had the cheapest double-glazing fitted,
and ultimately, cheap buckets are just the same – the
only good thing about them is the price. See Specification to find out why.
- Specification. Once you’ve decided the type of bucket you need – Digging,
Ditching, XHD etc. – what you really need to know is the specification,
in order to make a true comparison of what you’re getting
for your money. Unfortunately, not all bucket manufacturers
are as honest and forthcoming with
this data, and for good reason too. These are the key criteria:
a. Materials: Cheap steel, with low hardness (through,
not just surface) is one of the most common problems
with cheap
kit. For
larger gauge,
high wear
applications,
we always use Hardox 400 (see our BUCKETS page for full
information on this product) a registered and highly
regarded trademark
product, but
some rivals
will fob
you off with a specification that quotes for "Hardbox"!
b. Bosses: Another trick to cut cost out of buckets is to
delete the machined pin bosses from the bucket pivot plates.
This
is done in two
ways;
- Drilling the pivot plates – this method offers
a poorer bearing characteristic than welded-in,
machined bosses,
and will result in the pin holes wearing or
even stretching far quicker than with welded-in
bosses.
- Welding ‘dummy’ pins into the pivot plates for Quick Hitch buckets.
This is fine, until the pins wear, and then how do you replace/repair the pins?
With conventionally fitted pins, you can at least turn the pins through 180 degrees
to get some more wear out of them, without any special tools, but if they’re
welded in place it’s far more complicated.
c. Size: It sounds obvious, but cheaper buckets are
very often smaller! How? Well most buckets are bought
and
sold on their
cut width, but
that’s only
one key dimension, and the depth and height also factor
into the overall capacity. We will supply all these
key dimensions, and more, to our customers, so you
don’t
need to mess about with buckets which can often be
as much as 25% lower in capacity?
d. Delivery: Your buying a bucket to fulfil a specific
need, so you’ll
want to know when you can have a bucket delivered, and how much you will be charged
for delivery to you or your site. If it’s being
made to order, you also need to know an honest and accurate
manufacture time. We NEVER mislead customers
about any of these issues, but sadly we do know of numerous
cases where customers feel they have been let down by
other
suppliers. Be sure you can trust your
bucket supplier.
- Manufacture Time: We always try to sell customers
the right bucket/attachment for their job, rather than
just
using the ‘let’s shift what we have
in stock’ approach. Often we have stock of the
right kit, but equally there are times where we need
to manufacture
to customers requirements. In
this case,
we will tell you an accurate build date, at the time
of order, and we will stick to it. As a rough guide,
we can
normally
guarantee the following lead
times for
buckets:
a. Excavators from 0.5 to 5 tonnes; 5 working
days.
b. Excavators from 5 to 10 tonnes; 7 working days.
c. Excavators from 10 to 20 tonnes; 10 working days.
d. Excavators from 20 to 40 tonnes; 14 working days.
e. Excavators over 40 tonnes; 21 working days.
Changing Buckets & Attachments:
This is a simple, step-by-step
method of connecting any dipper end attachment:
- Try to ensure bucket is on level ground, or at very least
is level with your excavator, at mid reach, so the dipper
is in a
vertical
position.
- Align the dipper above the bucket pivots and extend
the bucket ram out (i.e. curl-in, pulling right control
lever
to the left)
so that
the bucket
link end
is lower than the dipper end.
- Drop the bucket link into the rear pivot location
of the bucket.
- Align the bucket link pinhole with the rear bucket
pivot pinholes.
- Insert the rear bucket pin.
- Lift the dipper until bucket is clear of ground.
- Retract the bucket ram, and angle the dipper, in order
to align the dipper end pinhole with the front bucket
pivot pinholes.
- Insert front bucket pin.
- Check bucket/attachment pins are properly secured
with the correct retaining clips or bolts. Unsecured
pins can
easily
come adrift
causing damage to
the bucket/attachment and the excavator, as well
as posing a safety issue.
- Ensure pins are greased.
- Carefully rotate bucket through full range
of boom, dipper and bucket ram movements tacking
care
to check
for any potential
collision
(especially
near
the dipper and link ends where the leverage is
highest) in order to ensure the bucket/attachment
you have
fitted is
compatible with your
machine
and is not
faulty.
Ultimately, for speed and ease of use, we would
highly recommend using one of our Quick Hitches – whatever
the size of your excavator. Repairs:
Buckets for machines under ten tonnes in weight can rarely
be repaired when worn. This is because the cost of removing
and
then replacing
parts can be
more than
the price of a new bucket.
We can offer a repair service
for large excavators buckets (for excavators over 10 tonnes),
although we need to
see the buckets
at our works
in order to give
an accurate quotation. Repair options include:
- Re-pivoting: changing bucket pivots (where suitable)
to suit different excavator set-up.
- New cutting edges: replacing worn edge. (May also
require remedial work to lower side reinforcing plates
and side
cutters)
- New tooth systems: fitted to new cutting edge.
- Wear ribs or straps: repairs to bucket back-plate.
It may not be economic (or possible) to repair buckets where:
- The bucket is bent or skewed (i.e. the opening
when viewed from the front is not ‘square’).
- The parent metals of the main shell structure
are worn beyond sensible limits.
- There are too many areas in need of change/repaired.
Bucket Teeth:
Worn teeth increase wear on boom pins and bushes,
make the engine use more fuel and increase the time of excavation.
Teeth should
be inspected
and
replaced at
regular intervals.
RUBBER TRACKS
DIGBITS have specialised in the supply of rubber tracks since 1991. Our mini excavator rubber tracks come with a 1000
hour, or one year’s
warranty*. Bear in mind that many excavator manufacturers
do not cover tracks in their warranty
schedule, and are therefore very unlikely to cover
replacement/second fit tracks.
However, even our
warranty does not include for abuse, only manufacturing
defects. Observing the
guidelines
in this section
will help ensure
you get the longest,
safest service from your new rubber tracks.
*This
does not apply to skid steer loader tracks, and machines have
a travel speed over 3 mph,
where the
warranty is 500
hours, or six
months. Ground Conditions and Use:
Rubber tracks were designed primarily
to avoid damage by steel tracks on paved surfaces, for
use on flat,
hard surfaces.
To get best life from your rubber
tracks, it is vital to follow the guidelines below, as
well as
any guidelines
in your machine’s excavator operators
manual:
- Surfaces: Avoid, as far as possible,
using the machine on sharp, uneven surfaces.
- Debris: Keep the tracks clean of soil,
stones and other debris by keeping your
work area
tidy. In quarries
where
very large
(100 tonne
plus) excavators
work, there is often a small bulldozer
working, just for this purpose – it
does pay dividends!
- Clogging: During either cold and/or
very wet weather mud and debris can freeze
and/or
dry
solid within
the tracks. Parking the machine
overnight or for long
periods on timbers will to help avoid
these issues.
- Tension: Keep tracks tensioned correctly.
De-tracking can cause extensive damage
to the core wires of
the tracks, especially
of
the sprocket punctures
the rubber.
- Speed: Be aware that constant use
of fast travel will severely reduce
track life. In
rough terms,
doubling tracking speed
will cut track
life expectancy by 75%.
- Dozer work: Excessive use of the
dozer blade will put more stress
on the tracks
than ordinary
tracking
and digging,
especially
if
debris become
trapped
in the
tracks. (Remember that on larger
machines, dozers have far heavier
tracks than
the equivalent weight
of excavator,
because
of this
fact.)
- Edges: Balancing the machine
over an edge (e.g. high kerb)
can damage
tracks and undercarriage.
- Steps: When tracking the machine
up a step-change in gradient
(e.g. kerb
or step),
try to approach
head-on and
use the
bucket to aid the
climb, remembering
to work the machine within
the stability parameters set by the
manufacturer.
- Kerbs: Do not drive with
the track edges pressed against,
or up kerbs
or other hard
step changes.
- Turns: Avoid fast, sharp
turns, especially on either
very grippy
or very soft ground.
- Transporting: Transporting
or lifting the excavator
with chains/straps bending
or cutting
into the
rubber will shorten
life and may damage
them. (See further
notes in TRANSPORTATION section.)
- Repairs: Always repair
cuts and damage to
avoid corrosion of the
track core
wires and metal
inserts.
- Undercarriage:
Always check the
condition of
your undercarriage
components.
(See
UNDERCARRIAGE section.)
- As far as possible,
limit the exposure
of new tracks
to oil,
grease, salt,
excessive sunlight
and moisture
whilst in
storage.
In use it
is impossible to
completely avoid
all of these, but
be aware
they
all may
reduce track
life.
- Avoid bending
or folding new
tracks sharply
when
storing.
Track Sizes:
It used to be possible to identify track from
just three key dimensional features;
- Width – the overall tread width of the track
- Pitch the spacing between the centres
of the metal links/inserts
- Links - the number of metal links/inserts
e.g. 230x072x42 = 230mm wide, 72mm
pitch, with 42 links
However, as track and undercarriage
technology has evolved, there are other key criteria
to be identified.
Track
inserts can be
designed to mesh specifically
with different types of rollers, also
some tracks have ‘offset’ type
treads where the guides for the sprocket,
rollers and idlers are not in the centre
of the metal inserts. Tread types also
factor into this.
Hence, the plain old
230x072x42 track has now become
(in our full size designation)
a 230x072x42
XAR.
Not all manufacturers like to
put the full (or even partial) information
onto
their
tracks, which is
why, to be safe
and ensure we offer
you the correct tracks, we’d usually
prefer to know the exact make and model
of machine when we are quoting you. We
have a computerised database of about
3,800 machines
(and
increasing) to ensure you get the right
tracks.
Due to the growing complexity
of track systems, getting the wrong tracks
is
not always immediately
apparent.
We have
heard stories
of our competitors
offering
and tracks which ‘will fit’,
often at a peculiarly low price, only
for them to fail within 12 months.
When
you consider the potential damage to
other undercarriage components, the
cost
and inconvenience
of unnecessary
site visits for your
fitter, and the upset
for your customers, is it really worth
saving a few pounds on a track?
If we
are not sure our tracks will fit your machine, we will tell you,
and also
advise
you that (even
though they
may
be more expensive)
it
may be worth
buying
the genuine parts in this instance. Changing
a rubber track:
If only one track is replaced at a time,
make sure that the other one has some tread
left
.If one
track is nearly
bald,
and the
other is
new then
the newer
track can take most of the tractive effort.
This again will not help to prolong life.
- First place the excavator on firm, level
ground.
- Next swing the machine round and push
up with the bucket to raise the track off
the
ground.
- Before proceeding further remove the
ignition key and put wooden chocks under
the excavator
to prevent
it dropping
in
case of a
mechanical or
hydraulic failure.
- Next reduce track tension by removing
the grease nipple and pushing the end idler
assembly
to exude
the grease.
- Remove old track, checking that the
new track is the correct size.
- Fit new track, putting sprocket end
on first.
- Replace grease nipple and re-tension
the track, as detailed in the ‘Tensioning’ section,
using your grease gun.
- Before removing the timber and lowering
the machine to the ground, check that
under carriage
components
are not
worn.
Tensioning:
The correct tension for a 1.5 tonne mini
excavator is normally about 10-15mm up
and down movement
in the middle,
but can
be greater for
larger excavators.
These figures give a rough guide:
1.0 to 1.9 tonne minis 10-15mm
2.0 to 2.9 tonne minis 30-35mm
3.0 to 5.0 tonne minis 40-45mm
Re-check
the tension after and hour or so of
operation, not least
because this is
unfortunately the
most common
time
for
the idler adjuster
seals to fail.
Check track tension every
100 hours.
If the track is too slack, it may come
off whilst turning in soft ground.
If too tight
then hard
stones carried
round on
to the sprocket
may
split the track.
UNDERCARRIAGE COMPONENTS
Worn undercarriage components, particularly
worn drive sprockets, will shorten track
life and
greatly increase
the strain on
track motors
and gearboxes.
There are also other issues to consider:
Sprockets
The sprockets should normally be replaced
at the same time as worn out tracks.
Effects of
worn sprockets
include:
- Accelerated track wear.
- Slipping in tracks causing shock
loadings to drive motor.
- Increased likelihood of de-tracking and subsequent damage to tracks.
Bottom
Rollers
Bottom rollers are designed to take
transfer the majority the excavators
weight and
dynamic forces,
through the
tracks, and
onto the ground.
Check for wear on
a regular basis. It is best to replace
all the bottom rollers on one side.
If only one
roller
per side
is changed, then
as the new
roller
may be slightly
larger
in diameter it will carry a higher
load and have a shorter life.
Backlash or play in the bottom rollers
will:
- Reduce the excavator’s stability.
- Increase the point loadings of less
worn rollers, thereby increasing
peak ground bearing
pressure.
- Accelerate track wear.
- Increase the likelihood of
de-tracking and subsequent
damage to tracks.
- Increase the load on the
track motor and gearbox.
Top Rollers
The top rollers are designed to carry
the tracks over the top of the track
frame
and are part
of the tensioning
system.
The
clearance
over
the track
frame afforded
by the top rollers is useful in terms
of allowing debris to fall free of
the tracks,
rather than
becoming wedged
between the track
and the
upper
surface of
the track frame.
Wear in top rollers if often neglected
and they are only replaced when it
is catastrophic, causing
problems
with:
- Loss of track tension.
- Increase the likelihood of de-tracking and
subsequent damage to tracks.
Idler
Wheels
The idler wheels are a fundamental
component of the undercarriage. As
well as transferring
some
of the
track frame loads
into the tracks, their
key
function
is to feed the tension from the adjuster
into the tracks. Failure will:
- Reduce the excavator’s stability.
- Result in a loss of track tension.
- Increase the point loadings on
rollers, thereby increasing
peak ground bearing
pressure.
- Accelerate track wear.
- Increase the likelihood
of de-tracking and
subsequent damage
to tracks.
- Increase the load on
the track motor and
gearbox.
BOOM PINS, BUSHES,
SEALS & SHIMS
When components on the excavator
arm are worn it becomes very difficult
to dig or
position
attachments
with
accuracy. Ultimately,
components
failing can cause
injury or death.
Digbits stock tens
of thousands of pins, bushes, shims, dust seals and
link arms
for machines
from under one
tonne up
to over 45 tonnes. Damage Prevention:
Regular inspections (as detailed
by your manufacturer) and use of
the grease
gun
are vital. Expensive
damage can be
caused if
pins
or bushes
are allowed
to wear to the point of failure.
We frequently supply new dipper-end
bosses
as a
result of unnecessary damage caused
in this way.
Removing Old Bushes:
Removing old, worn bushes can be
a problem. One good method for
steel bushes is to
put a ring
of weld
on the inside
of the bush.
As the
weld cools the
bush will contract and shrink.
It can
then be tapped out gently.
Important! Never hit hardened
steel bushes directly with a
steel hammer – they
can shatter –, use a soft metal mallet or a wooden block, and always
wear eye protection.
Important! Never use excessive
force when removing or fitting
hardened
steel bushes
into housings.
In extreme
cases the
bush can distort
the housing, causing misalignment
and permanent damage, and may
also shatter. Fitting New Bushes:
When new machines are assembled
in the factory, hardened steel
bushes
are often ‘shrunk
fit’ or ‘freeze fit’ into
housings/bosses, by dipping them
into liquid nitrogen, prior to
fitting. If you do not have access
to these facilities, chilling
the bushes in an ordinary domestic
freeze (wrap them up so you don’t
get oil and grease on anything
edible!) will serve the same
purpose.
Don’t be tempted to apply heat to the housing/boss, in an attempt to
expand it, as this rarely works and often (if the walls expand inwards) makes
the job
even harder.
Important! Never hit hardened
steel bushes directly with a
steel hammer – they
can shatter –, use a soft metal mallet or a wooden block, and always
wear eye protection.
Important! Never use excessive
force when removing or fitting
hardened
steel bushes
into housings.
In extreme
cases the
bush can distort
the housing, causing misalignment
and permanent damage, and may
also shatter.
TRANSPORTATION
- Rope or strap the excavator
securely.
- Secure the excavator on
your trailer or lorry using
the track
frame and
not the rubber
tracks,
as this
can damage
the tracks,
and is may
also allow
the machine
to move.
- Use the slew lock pin.
- Caution should be exercised
when carrying buckets and
attachments as they are heavy
and may take
the vehicle over the legal
weight limit.
LIFTING
In general, excavators should
not strictly be used as cranes,
even
if they have
check valves
fitted
to their
lift rams.
However, there
are certain circumstances where it is
necessary to lift
using and excavator, particularly
where
it is safer
than manual
handling.
We do supply pallet
fork attachments, block/kerb
grabs, and also
lifting eyes on our larger
quick hitches,
all of which
are tested.
You MUST check
to the safety and integrity
of any such
equipment and procedures
with the relevant
lifting ad safety bodies,
beforehand, taking
into account:
- Seek advice from
qualified lifting gear
safety inspectors.
- All lifting attachments
must be tested and
certified on a
regular basis, by
qualified lifting
gear safety inspectors.
- As well as the
attachments, your
machine itself
should be tested
(taking into
account the manufacturers
declared
safe
working limits)
and the
safe working
load displayed clearly
on the excavator
arm.
- Never assume that
an excavator can
lift to the
capacity
of it’s attachment – normally
the attachment’s
capacity should exceed
that of the excavator.
- Remember to account
for the weight of
the attachment on
the
excavator
arm, and
in the
case of lifting
eyes on Quick
Hitches,
the weight
of any bucket attached.
It is clearly advisable
to
keep this to a minimum.
- Never allow co-workers
or spectators into
the working arc of
the machine,
especially under
a raised load.
- Never loop chains
or straps over the
bucket linkage and
tipping linkage,
as
this is unsafe
and will cause
damage to the excavator.
- Notes on OPERATING should be read.
HYDRAULIC RAM REPAIRS
We find that an increasing
number of our customers
do not wish
to tackle re-build
or repairs on
hydraulic rams.
We
do not
offer this
service,
and would therefore
advise customers
to look for a suitable
hydraulic
engineer
locally,
which
can
normally
be found
in your Yellow
Pages, or on the
Yell.com
website.
In the Midlands
area, we can recommend
Midland Hydraulics
in Tamworth; Tel:
01827 59011.
HYDRAULIC
HOSES
We don’t
get involved with
hoses, but would
advise customers
looking for hoses can consider one of two options:
- For the lowest price,
find a local hydraulics
specialist in
your Yellow
Pages, or on
the Yell.com website.
You will have
to visit
their premises,
or submit
a detailed specification/drawing
of the hose you
need.
- Call any of
the large, national
on-site
hose
fitters – Pirtek
and Dunlop Hyflex
are two examples – and
they will come
out to the machine,
identify
the faulty hose,
manufacture a
replacement and
fit it. This
is the more expensive
option, but you
are paying for
convenience
and expertise.
SLEW
RING & PINION
PROBLEMS
Older machines
may have slew ring
wear
problems.
We do
not cater
for this
and suggest that
you contact B & C
Reconditioning
[Gears] Ltd., on
01980 623210.
BUYING
YOUR EXCAVATOR
As
with any machinery, you can choose
to buy New, or
Used. Before
you look
at those
options
in detail,
consider
some
more general
criteria:
- Capacity:
What capacity
of machine
do you think
you need?
Excavators
are always
classified
by their
operating
weight – a 1.5 tonne mini weights about 1.5
tonnes or 1500kgs – and often model numbers refer to this. In simple terms,
a heavy machine with a bigger counterweight, can cope with a bigger boom/arm
assembly, with more engine power. Obviously other things change to accommodate
this – bigger track frames and motors to cope with the extra weight for
example – but
this is the
main, basic
difference
between different
sizes of excavator.
- Size: Do you
envisage any
size or weight
restrictions
for
your work?
Is it possible
you might buy
an excavator
that
is to large
for your
jobsites (or
your transport),
or
conversely,
might you
have reach/power
considerations
which rule
out smaller machines?
For example,
do you need
to dig to a
certain depth,
or
load over a
certain height? Do you
need to dig
narrow trenches,
or work
under/inside
of structures?
- Make: A
difficult question
this,
as you’ll rarely get an objective view
from other owners, but nevertheless, this is a good source of information. Things
to bear in mind are service costs and resale values – easily checked out – as
well as the
access to dealers
and
spare parts.
- Age: Diggers,
when looked
after properly,
can last
many years
(we
still stock
and sell parts
for popular
minis
built in the
mid 1980’s!) although as
a rule of thumb, you may need to be prepared for more expensive items – such
as slew rings – to fail on machines over 5 years old. Unless you’re
mechanically minded and like a bit of spanner work, or you’re confident
you can spot potential problems, stick to looking at machines under 5 years old.
Don’t think you’ll ever avoid running costs such as tracks unless
the machine is brand new – newer
machines can
use these just
as quickly
as older ones.
New
You can find
the nearest
manufacturer
main dealers
by using
the information
in the
CONTACTING
YOUR EXCAVATOR
MANUFACTURER
OR
DEALER section.
- Reputation:
Try and
check this out
with other
users/owners
before
you
go ahead
and buy,
to see
what feedback
you get
on:
a. Make – are
other owners happy with
it, and would they
buy again?
b.
Dealer – is
the service
and pricing
and location
satisfactory?
- Residuals:
Check the
second
hand plant directories – or ask to see the
dealers used machinery list – to
get an
idea of
what your
machine
might
be worth
if, and
when
you
need to
sell.
- Specifications:
The
big advantage with buying
new
is
that you can, within
reason,
buy
exactly the machine
you
need,
although
it’s
wise
to
take
some
advice
from
the
dealer
salesperson
as
to
what
might
be
saleable
when
you
come
to
dispose
of
the
machine.
Check
the
options
and
specifications
of
machines
against
one
another
for
comparison,
and
try
to
establish
which
are
most
important
to
you.
Used
There are
three main
alternatives
here – Dealers,
Small Ads,
Auctions - but you
would be
wise not
to consider
the two
latter
options
unless
you’re
confident
you know
what to
look out
for, and
how to
fix any
potential
gremlins.
Refer also
to the
information
in
the KNOW
YOUR MACHINE section.
- NEVER buy
a machine without
a
serial number
plate.
How
can
you order spares
for
it, or insure
it?
- CHECK that
the
model number
shown
on
the decals
matches
that
on
the
serial number
plate.
Incompetent
or
unscrupulous traders
may ‘cosmetically’ update
machines,
with
new
paint
and
decals
to
look
like
a
later
model.
Do
the
engine
numbers
match
those
on
the
serial
number
plate?
- CHECK the
origin of the
machine.
You
need to be
aware
that
grey
imports (machines
imported
from
outside
the
EU)
exist, and may
not
necessarily bear
any
resemblance
to
EU specification
machines.
Using
non-EU,
non
CE
marked machinery
is
not advisable.
- Dealers:
There
are manufacturers
main
dealers,
and also
machinery
traders,
who deal
in
all
kinds
of
new or
nearly
new machines.
Always
try
and check
out
a dealer’s reputation before you buy from them – they will generally
be professionally run and provide good back up, but as with any industry there
are rogues, and it’s not necessarily the smaller, independent outfits that
give the worst service. If you think you’ll
need
some
back-up
from
the dealer,
try and
buy from
dealers
who have
experience
and regular
sales
of
the
makes/models
of machine
you need,
rather
than
those
who are
selling
a one-off
deal.
- Small
Ads:
Smaller
owners
and dealers
frequently
advertise
excavators
in
trade
magazines.
As with
buying
cars
or commercial
vehicles,
buying
from
these
sources
will
place
more
risk
and responsibility
with
the
buyer,
in terms
of
ensuring
the machinery
is in
good
condition,
and
is not
stolen,
but
ultimately
there
should
be significant
saving
by cutting
out the
dealer.
However,
you
must
ask yourself
whether
you
are really
qualified
to make
informed,
competent
decisions?
- Auctions:
There
are some
very
good
bargains
to be
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