MMLS3 OPERATOR’S MANUAL OPERATOR’S MANUAL The aim of the MMLS3 Operators Manual is to give information regarding safe and efficient techniques in operating the MMLS3. The machine

MMLS3 OPERATOR’S MANUAL

The aim of the MMLS3 Operators Manual is

to give information regarding safe and

efficient techniques in operating the MMLS3.

The machine is a scaled down heavy vehicle

simulator used for accelerated trafficking of

model- or full scale pavements.

MMLS3 is also known as PaveTesting MLS11

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MMLS3 operator’s manual Note: MMLS3 is also known as PaveTesting MLS11

Contents SECTION 1: UNPACKING AND INSPECTION ..................................1

1.1 Packing list ..............................................................................1 1.2 Unpacking ...............................................................................2 1.3 Inspect the machine for damage during transport ....................3

SECTION 2: FEATURES AND DESCRIPTION ....................................4 SECTION 3: USING THE MACHINE ....................................................8

3. Operation ......................................................................................8 3.1 Setting the wheel load .............................................................9

3.1.1 Measuring the wheel load ...................................................9 3.1.2 Adjusting the wheel load ...................................................12

3.2 Setting up the machine on the pavement ...............................13 3.2.1 Getting the machine into position .....................................13 3.2.2 Adjusting the height ..........................................................15

3.3 Running the machine .............................................................19 SECTION 4: MAINTENANCE .............................................................21

4.1 The yellow (polyurethane) guide wheels ...............................21 4.2 The drive belts .......................................................................23 4.3 The gap between the rails and the drum ................................23 4.4 Aligning the drive drum ........................................................25 4.5 Changing a tire ......................................................................27 4.6 Removing and replacing the springs......................................31

APPENDIX A: Using the Varispeed motor controller ......................32 APPENDIX B: The lateral displacement system ...............................34 APPENDIX C: Maintenance checklist ..............................................35 APPENDIX D: Circuit diagrams .......................................................40 APPENDIX E: Technical Specifications ..........................................45


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SECTION 1: UNPACKING AND INSPECTION

1.1 Packing list

You should have received the following items

1. The MMLS3 machine frame plus the following accessories:

a. One steerable “jockey wheel” and two fixed transport

castors wheels. (See Fig.1(h).

b. Two “skate boards” with base plates (See Fig.1(g))

c. Two link arms, about 350mm long, to link the machine

to the base plates (See fig. 4)

2. An “electric orange” control box

3. An electronic calibration unit to set the wheel load (See Fig.3).

This is packed in a wooden box, about 400x300x300mm.

4. One spare pneumatic wheel, complete with bearings and shaft.

5. Eight spare yellow guide wheels

6. The following metric tools

a. 10mm wrench

b. 13mm wrench

c. 16mm wrench

d. 17mm wrench

e. 14mm wrench

f. 5mm Allan key

g. 4mm Allan key

7. Suspension measuring gauge (See Fig.5)

8. A copy of this operator’s manual


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1.2 Unpacking

The machine comes strapped to a wooden pallet inside a

wooden crate and can be handled by either a forklift or a crane.

Once removed from the pallet the machine should not be

handled by a forklift, which will damage its underside. Off the

pallet the machine can be moved around on its own transport

wheels, or handled by crane. The crane should be attached to

the single shackle on top of the frame. The 300mm rubber

trafficking wheels cannot support the weight of the machine.

Care must be taken not to overload them.

The control unit, calibration unit, the two links for the lateral

displacement system, some other small parts and tools and the

manuals are packed in a separate smaller crate.

1.2.1 Open the large crate by undoing all the screws on the top and

remove the top plywood sheet. Also remove at least one of the

side panels. Remove the straps and, using a crane, lift the

machine from the pallet by the single shackle on top. Take care

not to bump the small bracket on the gearbox at the end of the

machine. Lower it to about 300mm from the floor, but do not

put the machine down.

1.1.2 Remove the jockey wheel from the pallet and mount it while the

machine is still hanging from the crane and then lower it to

stand on its wheels.

To mount the jockey wheel push the two 25mm holes

horizontally over the two studs at the end of the machine (see

Fig1), then slide it slightly upwards and engage the pin

The machine can now be wheeled around.

1.1.3 Remove the base plates and “skate boards” from the pallet.

These are used for the lateral displacement of the machine when

in operation. The “skate boards” are the two channel sections,

each with four wheels and two self-aligning bearings.


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1.3 Inspect the machine for damage during transport

Visually check for bent or broken parts. If anything looks

suspicious, please contact the supplier.


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SECTION 2: FEATURES AND DESCRIPTION

The MMLS is a scaled down heavy vehicle simulator used for

accelerated trafficking of model- or full scale pavements. The four

300mm diameter single wheels can typically apply 7200 real wheel loads

per hour. Normal inflation pressure for the pneumatic tyres is 700 kPa,

with a maximum of 800 kPa. The maximum wheel load is 2700 Newton.

The machine is supplied with the wheel load set to 2700 Newton. If the

machine is transported by air, the tyres are deflated to about 200 kPa.

Please inflate to the correct pressure before testing.

The machine contains the following main components: (See fig 1).

a) The rigid frame with four adjustable legs.

b) Looped guide rails mounted on the frame.

c) Four bogie carriages, each with one 300mm diameter pneumatic

wheel and six guide wheels.

d) Four link sections, each with six guide wheels.

e) The drive drum

f) The curved wheel guide

g) The mechanism for lateral displacement

h) Detachable castors for moving the machine over short distances.

i) The control unit in a separate box.

The bogies and link sections are linked together to form an endless chain

with a total of 48 guide wheels and four pneumatic trafficking wheels.

The guide wheels move along the two sets of guide rails. When a bogie

moves along the bottom straight section of the rails, the pneumatic tyre is

in contact with the underlying pavement, applying a load to it.

The spring loaded drive drum pinches some of the guide wheels against

the outer rail. As the drum rotates the guide wheels are moved along in

much the same way as with a planet gear system, driving the chain of

bogies around. The drum is driven by a 1.5 kW variable speed electric

motor.

The trafficking wheel of each bogie has an adjustable suspension system

by which the wheel load can be set. The suspension has a displacement

travel of about 20 mm. Once set, the geometry of the suspension system


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makes the wheel load practically independent (±5%) of displacement

within the 20mm range. When in operation, the suspension is kept

within its working range by adjusting the legs on the fixed frame. Care

should be taken not to overload the suspension by lowering the frame too

far.

The control unit is housed in a 400 x 500 x 200 “electric orange” IP65

(weather proof) metal box. It contains the following components:

1. The motor controller. See Appendix A for operating details.

2. Two counters to count the total number of wheel loads. One

counter is not resetable and its reading must be multiplied by

10, while the other one can be preset to stop the machine after a

set number of wheel loads.

3. The control system for the lateral displacement of the wheels on

the pavement.

To simulate lateral spread of wheel loads on the pavement, the

entire machine is displaced in the lateral direction by an electric

motor. The motor is controlled in such a way that more wheel

loads are applied near the centre of the track, giving a Normal

(Raleigh) distribution of loads over the width of the track. See

Appendix B for more details.

The 6 amp. trip switch (marked DC) on the right hand side of

the main switch serves as an electronic shear pin and will switch

the machine. The total width of the lateral spread of the wheels

on the pavement can be set by the knob next to the counter.

Power supply to the machine is 220 Volt 50/60 Hz AC at about 1.5 kW

(7 Amp).

Using the machine on wet pavements

The MMLS3 may be used on wet pavements. Most parts of the machine

(including the ball bearings in all the wheels) are made of stainless steel

or other corrosion resistant material. The electric connectors and

enclosures are of the IP65 (weather proof) type. It must be kept in mind,


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however, that under wet and dirty conditions faster than normal wear and

tear will occur which may shorten the life of the machine or some of its

components.


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SECTION 3: USING THE MACHINE

3. Operation

To operate the machine, follow the following steps:

Set the wheel load and tyre pressure as described under 3.1.

Move the machine into position by its transport wheels or by

crane as described under 3.2.1

Mount the base plates and “skate boards” for lateral movement

as described under 3.2.1.

Connect the three electric cables from the control box to the

machine as described under 3.3.2

Set the suspension operating level as described under 3.2.2

Set the lateral displacement as described in 3.3.6 below

Set the speed to a low value (say 10 Hz.) as described in

Appendix A below and press the green RUN button on the

outside of the orange cabinet and let the machine run for at least

one revolution to make sure that it is clear to run. Press the red

STOP button to stop the machine.

(To use the RUN and STOP buttons on the keypad, see section

3.3.8 below or Appendix A.

Record the reading on the right hand (mechanical) wheel

counter.

Set the electronic wheel counter to the desired number of axles

after which the machine has to stop.

Set the speed to the desired value as described in Appendix A

below (max. 48 Hz)

Press the green RUN button to run the machine.


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Press the red STOP button to stop the machine when necessary.

Before using the machine on wet pavements, read section 2 in

Supplementary Manual.

Every 500 000 wheel loads, apply grease to the side walls of the

guide wheels as described under 4.1

Read the maintenance checklist in Appendix C

3.1 Setting the wheel load

The load that is applied to the pavement by the trafficking

wheels can be set by adjusting the suspension springs on the

bogies. The suspension system is designed so that the wheel

load is practically independent of the vertical displacement of

the wheel. It is thus possible to set the wheel load beforehand

and, as long as it stays within the specified displacement range

during operation, rutting of the pavement or vertical displace-

ment of the machine frame will not affect it. This makes it

unnecessary to continuously monitor the wheel load during

operation.

3.1.1 Measuring the wheel load

Refer to fig. 3

The wheel load can be measured or set with the aid of the

calibration unit.

3.1.1.1 Take the calibration unit from its wooden box and unscrew the

50mm diameter flange and the two M10 nuts from the bottom

end of the unit. Mount the unit onto the channel beam on top of

the machine by means of the two M10 bolts. (It may be

convenient to completely remove one of the safety covers by


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removing its hinge pins.) Mount and hand tighten the flange.

Plug the unit into a 220 Volt AC supply.

3.1.1.2 Handling the chain of bogies by the round wheel shafts on the

link sections only, move one of the 300mm wheels to be exactly

underneath the flange of the calibration unit. Hold the bogie

firmly in place and turn the crank to push down onto the wheel.

3.1.1.3 Observe one of the two 25mm diameter rubber stoppers on the

wheel trailing arms (fig.3). As the wheel is pushed down, the

stopper will move away from the frame of the bogie. Turn the

crank until the gap is about 10mm and read the force from the

display. NEVER INCREASE THE GAP TO MORE THAN 20

mm, BECAUSE THE SPRINGS WILL BE OVER STRESSED.

Because of friction in the system a higher reading may be

observed while the wheel is pushed down than while letting it

move back. Turn the crank forwards and backwards about one

revolution at a time and note the average reading.

3.1.1.4 From time to time apply some MS grease to the threaded rod of

the calibration unit.

3.1.2 Adjusting the wheel load

3.1.2.1 Measure the wheel load as described in 3.1.1 above.

3.1.2.2 Refer to fig. 3 and apply a small amount of MS grease to the

thread on the spring shaft as well as one of the faces of a round

spacer (supplied) and insert it, small end first, over the open end

of the spring shaft, followed by a M16 nut (nut A). NEVER

USE A STAINLESS STEEL NUT, as it will seize onto the

shaft. If the wheel load is to be increased, tighten the nut to

compress the spring by about 5 mm, otherwise compress it by

about 2 mm. Release the locknut (nut B) on the flange at the

opposite side of the spring and move it away from the flange.

3.1.2.3 Adjust the position of flange B on the spring shaft by rotating

the spring and both flanges simultaneously. Make a mark on


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the flange and record the number of turns. To increase the

load, screw the flange away from the u-bracket (i.e. compressing

the spring). It should be possible to rotate the spring by hand if

nut A is, at the same time, rotated in the same direction by a

24mm ring wrench. One end of the spring assembly may be

lifted out of the spring support to get a better grip. Otherwise a

strap wrench may be used.

3.1.2.4 With the spring in position, release nut A, but do not remove it

yet.

3.1.2.5 Repeat the above operations for the other spring, using the same

number of turns.

3.1.2.6 Measure the wheel load as described in 3.1.1 above.

3.1.2.7 If the load is still not correct, use the measured load increment

and number of turns (see 3.1.2.3) to calculate the required

number of turns to arrive at the correct value and repeat the

above steps until the wheel load is correctly set. Also measure

the length of both springs. They should not differ by more than

2 mm.

3.1.2.8 REMOVE THE NUTS AND SPACERS ON BOTH SPRINGS.

3.1.2.9 Adjust the tyre pressure if necessary.

3.2 Setting up the machine on the pavement

To prevent damage to the machine, it is important that the pavement be

fairly flat and firm enough to carry the weight of the machine. Keep in

mind that the wheels travel at high speed and that bumps or holes in the

pavement may cause large shock loads.

3.2.1 Getting the machine into position

3.2.1.1 Move the machine in position on the test pavement by its

transport wheels or by crane.


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The jockey wheel with the beam is mounted by pushing the two

25mm holes horizontally over the two studs at the end of the

machine, then moving it slightly upwards and engaging the pin.

The two fixed wheels are mounted, one on each side of the

machine, by engaging the four 10mm pins vertically upwards

into the holes in the L-beams and then engaging the horizontal

pin to keep it from dropping out again. Install the R-clips into

the pins to keep them in place.

3.2.1.2 Refer to fig. 4 and slide the two base plates and “skate boards”,

one set at each end, in underneath the machine from the sides

and attach the links between the base plates and the lever arms.

Insert the R-clips to retain the links.

3.2.1.3 Lower the legs by turning the crank handles on top so that they

engage with the four bearings on the two skateboards. Under

operating conditions it may be necessary to fix the base plates to

the pavement to prevent them from moving around. The best

way is to drill 8mm holes about 50mm deep into the pavement

through the two holes in the base plate and to insert a 8mm steel

rod into each hole. Take care to fix the base plates in such a

way that the wheels of the skate boards will not jam on them,

i.e. they must stay 100% perpendicular to the centre line of the

machine.

3.2.1.4 Raise the machine high enough on its legs to remove the three

transport wheels. Adjust the two legs at one end of the machine

simultaneously by an equal amount and observe the bubble in

the spirit level mounted on top of the frame. This will avoid

twisting the frame by allowing it to stand on two diagonal legs

only.

3.2.2 Adjusting the height

The load of the wheels on the pavement is determined by the

spring settings and is practically independent of displacement.


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Refer to fig. 5 below. It shows a side view of the bogie

suspension system. In the machine the system can only be seen

from the top.

The large spring at the bottom pushes the rubber wheel

downwards to create the load of the wheel onto the pavement.

When the machine is lifted off the pavement the wheels moves

downwards so that the gap closes until the rubber stoppers make

contact with the metal frame of the bogie. The stoppers then

bear the force of the spring and the wheel cannot move further

downwards.

When the machine is lowered so that the wheel makes contact

with the pavement, the pavement starts to push the wheel

upwards and the stoppers move away from the metal frame.

The pavement now counteracts the force of the spring and the

set wheel load is applied to the pavement.

To be sure that the correct load is applied to the pavement the

stoppers should not make contact with the metal frame of the

bogie. To allow for unevenness of the pavement as the wheel

travels down the pavement test section, the initial gap should be

set large enough. The required initial gap is about 10mm. (See

Adjusting the wheel load under 3.1 above).

The 10mm suspension gap can be measured with the supplied

tool, as indicated in fig. 5. You can also feel the gap with your

finger.

To make the gap larger the machine has to be adjusted lower

onto the pavement by turning the handles on top in an anti-

clockwise direction. In the same way, to make the gap smaller,

the machine must be raised from the pavement by turning the

handles in a clockwise direction.


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3.2.2.1 Look through the large inspection opening in the side of the

machine and move any one bogie until the forward four of its

six yellow guide wheels are just out of the curve coming down

on the opposite side of the drive drum, and onto the start of the

bottom straight rail section. The bogies may be moved using

the control unit, set to a low speed (6 - 10 Hz), or by hand. To

avoid injury when moving it by hand, only handle it by the

round axles of the link sections.

3.2.2.2 Evenly lower the machine frame until the two black rubber

stoppers at the end of the trailing arms that hold the rubber

wheel just start to move away from the metal plate underneath

it. (See fig 3)

3.2.2.3 DISCONNECT THE MOTOR CONTROL UNIT FROM THE

MAINS. Refer to fig. 5, p16 and find the PVC measuring tool,

shaped like a human leg and foot. The “toe” of the gauge is

8mm high, increasing to 10mm where it is attached to the “leg”.

Holding the gauge by the “leg”, measure the gap underneath the

rubber stopper. Only one of the two stoppers needs to be

checked. Lowering the machine will increase the gap and vice

versa. The setting is correct when the “foot” fits in the gap

with little or no clearance. A tolerance of one or two mm to

either side is allowable.

3.2.2.4 Move the bogie forward until the forward two of its six yellow

guide wheels are just at the end of the bottom straight rail

section. ALWAYS DISCONNECT THE MAINS SUPPLY

BEFORE WORKING INSIDE THE MACHINE. Check that

the gap is still about the same. If not, adjust the two feet at that

end of the frame to correct it, even if it means that the machine

is not standing horizontal in the length-wise direction. Recheck

the gap in the first position.

3.2.2.5 Lock the four legs to prevent further rotation.


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3.3 Running the machine

3.3.1 Set the machine up as described under 3.2 above.

3.3.2 Connect the control unit to a 220 VAC supply and connect the

three cables to the machine. The red plug feeds 3-phase power

to the AC motor, the blue plug feeds power to the DC

servomotor for lateral displacement and the black plug handles

the counter and control circuits. Total consumption is about

1.5 kW.

3.3.3 Always first run the machine at a slow speed (10 Hz) for at least

one revolution of the bogie chain to make sure that nothing is in

the way and the machine is clear to run.

3.3.4 The motor speed is set by the small round knob on the motor

controller. Set to 48 Hz to obtain 7 200 axles/hour (2

axles/sec.) For more details on the operation of the motor

control unit, see appendix A.

3.3.5 With the machine running, press DISPL until the motor current

is displayed in Amps. (IOUT led is on) The current at full

speed should stay below 4.6 A. A higher current indicates

excessive friction somewhere. Stop the machine and

investigate. The unit will trip at about 5.5A, displaying oL3.

3.3.6 The lateral displacement system automatically switches on when

the main motor runs at more than about 20 Hz and switches off

when it is stopped or slowed down to below that speed. The

maximum displacement is 75mm (3”) to either side of the centre

line of the track (150mm (6”) total). This distance is

continuously adjustable down to zero by the multi-turn control

knob to the right of the counter in the control box. The

maximum setting on the control knob is 75, which gives the

maximum displacement. Setting the knob at a higher value will

not increase the displacement, but will distort the lateral spread

pattern of the wheels. See Appendix B for more details on the

lateral displacement system.


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3.3.7 After a few millimetres of rutting has developed, it may be

necessary to stop the machine and readjust the suspension gaps

as described under 3.2.2 above.

3.3.8 To use the RUN and STOP buttons on the keypad, (instead of

the green and red buttons on the outside if the box) the control

unit must be reprogrammed to MODE 1 as described in

appendix A.


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SECTION 4: MAINTENANCE

Also read the maintenance recommendations in Appendix C

4.1 The yellow (polyurethane) guide wheels

The two wheels in the centre of each bogie (in line with the

shaft of the rubber wheel) carries nearly all the load. Inspect

them from time to time for signs of deterioration. The guide

wheels is expected to last about 10 Million axle loads, at which

time cracks may appear in the polyurethane. Wheels showing

signs of deterioration may be exchanged into positions where

the load is smaller. It is also OK to keep on using the wheels

with some small cracks in it. Never install an old and a new

wheel on the same shaft. The diameter of the two wheels

should not differ by more than 0.5mm

The sides of the guide wheels rub against the Vesconite guide

rails to steer the bogies and link sections. Although Vesconite

is a good bearing material the wheels may wear under dusty or

dirty conditions. New wheels are 33mm wide. Measure the

width and replace the wheels when the width is less than 30mm,

or exchange it to a position that shows less wear.

To reduce wear a very small amount of grease is applied to the

outside sidewalls of the yellow guide wheels. It is very

important not to use too much grease, which may spread to the

running surface of the wheels and the drive drum. This will

reduce the friction and make it impossible for the drum to drive

the wheels. A good guideline is not to use more than a total of

about 2 ml. for the 48 wheels. Repeat the application after

every 500 000 wheel loads or after some hot, wet tests have

been done.

To remove a guide wheel, remove the cap screw and washer,

replace the cap screw, without the washer, to protect the screw

tread in the centre of the shaft and pull the wheel out with the

supplied puller.


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4.2 The drive belts

The drive drum is driven by two V-belts. From time to time

(say every 500 000 axle loads) Remove the safety cover (two

M6 bolts on top and two at the bottom) and inspect the belts for

wear and damage. Replace and/or tension the belts if

necessary. The longer belt is tensioned by moving the motor.

Make sure that the two pulleys are in the same plane by laying a

long straight edge along their front surfaces. The shorter belt is

tensioned automatically by a tension pulley. The type

specification for the inner belt is 13x1080, while the outer one is

an 13x1860

4.3 The gap between the rails and the drum

Refer to fig. 6. Where the top and bottom rails meet the

rotating drum that drives the bogies around, the gaps between

the drum and the rail ends should be between 0.2mm and 0.5mm

(measured with a feeler gauge) at its narrowest point. The shaft

of the drum is mounted on horizontal slides and is spring loaded

in the horizontal direction to pinch the yellow guide wheels

between the drum and the outer rail. When the machine

operates there are small horizontal movements of the drum,

which may wear the slides. This can cause the drum to displace

vertically, changing the gaps mentioned above.

It is thus necessary to check the gaps from time to time (say

after every 1 000 000 wheel loads) with a feeler gauge. It is

only necessary to measure the gaps on the top side, assuming

that if they are correct, the bottom ones will be correct as well.

Excessive vertical displacement of the drum will cause the drum

to scrape against the rail ends either at the top or bottom. This

will cause a scraping sound and the motor will draw more

current to overcome the additional friction. Monitor the motor

current as described under 3.3.5 above.


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Should the gaps need adjustment, proceed as follows:

Note: The following procedure assumes that the upper guide

rail ends have not been disturbed and can serve as

reference for the position of the drum. If this is not

true, the drum has to be re-aligned as described under

4.3 below.

4.3.1 On the pulley side, remove the safety cover and release the three

M8 nuts (13mm spanner) on the upper Vesconite slide. (Nuts

G, E & H on fig 6.). Push down the slide to take up any

clearance and retighten the nuts. Repeat on the other side of

the machine.

4.3.2 Release the four M10 nuts on the bearing plate (A, B, C & D), .

Release the lock nuts on the set crews (P & Q) at the bottom of

the bearing plate. With a feeler gauge measure the gap between

the drum and the upper guide rail end. Adjust it to between 0.2

and 0.5mm at the narrowest position by turning the set crews.

It may be necessary to slack off the setscrews and push the

bearing plate downward to increase the gap. Tighten all the

nuts. Lock the setscrews

Repeat on the other side.

4.4 Aligning the drive drum

Note: This procedure should only become necessary under exceptional

conditions. It is suggested that the manufactures be contacted

before it is undertaken

Refer to fig. 6.

The chain of bogies and link sections are driven around by the drive

drum which drives the guide wheels. This is done by pinching some of

the guide wheels between the rotating drum and the outer rail and driving

them forward like in a planar gear system. It is important that the two

wheels on the same axle are gripped simultaneously and released

simultaneously.


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The drum, curved outer rail and upper rail ends have been aligned for

proper working in the factory. As long as the upper rail ends are not

moved from the factory setting, they can be used as reference for the

position of the drum by setting the gap between them as described in 4.2

above.

If there is reason to believe that the machine frame has been distorted, or

the upper rail ends and the drive drum have both been moved, the

alignment of the drum relative to the outer rails must be checked and

adjusted if necessary.

To adjust the drum, proceed as follows:

4.4.1 Disconnect the machine from the mains supply.

4.4.2 Remove the curved safety cover at the end of the machine on

the drum side.

4.4.3 At that end of the machine, make sure that the machine frame is

square by measuring the diagonal distances from the bottom of

the left hand side panel to the top of the right hand panel as well

as from the bottom of the right hand panel to the top of the left

hand panel. The two distances should not differ by more than

2mm.

If adjustment is necessary, release the eight M10 bolts and nuts

holding the two stiffener plates at the end of the machine (four

per plate). Use a long carpenter’s clamp or similar to

diagonally press the frame in shape. Retighten the M10 nuts to

a torque of 67 Nm.

4.4.4 Select any axle of a link section on which the diameter of the

two yellow wheels are the same ( 0.1mm) and move the bogie

chain until that axle is on the lower guide rail end (see fig. 6).

The wheels should be free to be rotated by hand.

4.4.5 Through the opening at the end of the machine, pull the wheels

towards you. When they are more or less at position K to L in

fig 6, both should simultaneously (within 40mm of each other)


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be pinched between the drum and outer rails so that it is

impossible to rotate them by hand. Move the wheels further on

and they should both simultaneously be released somewhere

between positions M and N. If this is not true, adjust the left

and/or right hand bearing plates as described in 4.2.2 above, but

without referring to the gaps between the rail ends and the drum.

It may be necessary to release and adjust the top or bottom rail

ends to clear the drum.

4.4.6 With the drum properly adjusted, reset the gaps between the

drum and rail ends to 0.2 to 0.5 mm by moving the rail ends.

This can be done by releasing the bolts holding the rail ends to

the side panels. Make sure that the rail ends join the rails

smoothly. It is best to first set the rail side of the rail end to give

a smooth joint with the rail and lightly tighten the bolt on that

side. Then set the other end to obtain the required gap with the

drum. Tighten all the bolts and recheck the gaps.

4.4.7 Make sure that the guide wheels are free to move between the

bottom rail ends and the outer rails.

4.5 Changing a tire

4.5.1 Park the bogie so that the rubber wheel is right above the drive

motor.

4.5.2 Refer to section 4.6 and remove both springs from the bogie.

Note that you will have to lift the wheel slightly by hand to pull

out the second spring. The wheel will now rest on the drive

motor.

4.5.3 Remove the 300mm wheel from the bogie:

Refer to fig 8 and undo and remove the two M24 nuts, A & B,

at the ends of the wheel axle. Remove the stiffener plate, G, by

removing the six hex drive cap screws marked, F. The two

trailing arms, C & D, are held in position on the guide wheel

axle by two circlips each. Use circlip pliers and move the outer

circlip of one of the trailing arms as far as it will go towards the


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end of the guide wheel axle. Slide the trailing arm outwards so

that the wheel shaft can be disengaged and the 300mm wheel

removed.


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4.5.4 Remove the old tyre and tube from the rim:

If the tyre is not already flat, deflate to about 50 kPa and undo

the five M8 capscrews that hold the two rim halves together.

Then completely deflate the tyre and remove the bolts. Lay the

wheel down in a horizontal position with the bolt holes facing

upwards. Note that two of the holes are tapped (threaded).

Install the puller as indicated in the left hand picture below.

Screw the long bolts at least 15mm into the rim. Tighten the

nuts evenly by hand so that the cross beam is horizontal. Now

turn each nut half a turn at a time to pull the rim out. Use a

large screwdriver, or something similar, and push down the tyre

with a lever action as indicated in the right hand picture below.

Work around the rim until the tyre is free from the rim.

Remove the upper rim half. Lift off the old tire and tube. If it

sticks, use the screwdriver as for the upper rim half. The shaft

remains in the lower rim half.

4.5.5 Install the new tire.

Install the new tube into the new tire and inflate slightly so that

it does not make any folds. (top left picture below) Place the

lower rim half (the one without the slot for the valve) with the

axle on the supporting surface (top right picture below) lower

the new tire over the rim half so that the valve is exactly

between two holes (left lower picture) Make sure that the tube

is inflated enough so that it will not make any folds that may get

in between the two rim halves and insert the second rim half


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30

from the top and push it down as far as it will go. Apply some

lubricant to the treads of the five cap screws and insert them

with their flat washers (picture bottom right). Tighten them in

sequence, half a turn at a time, so that the two rim halves are

pulled together evenly. Tighten the cap screws to about 10

Nm, but take care that the rim does not rotate relative to the

tyre, as this will damage the valve.

4.5.6 Inflate the tyre to about 200 kPa and then tighten the 5 cap

screws to about 20 Newton-meter (200 lbf-inch). To prevent

damage to the Alan drive cap screw heads, use only a good

quality chrome vanadium Alan key and make sure that it is at all

times inserted to the full depth of the socket in the cap screw

head.

4.5.7 Inflate the tire to its full pressure and make sure that the shaft is

free to rotate in its bearings. If not, tap the shaft in an axial

direction with a soft hammer. Take care not to damage the

screw thread.


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4.5.8 Replace the wheel in the bogie and tighten nuts A & B. Move

the circlip back in place. Replace plate G and tighten

capscrews, F, to 20 Nm. Tighten nuts A & B as hard as you

can (100 Nm).

4.5.9 Replace the springs.

4.6 Removing and replacing the springs

Refer to fig. 2.

Springs that are not in the machine are compressed by a spacer

and a M16 nut (nut A) on the spring shaft. AFTER A SPRING

HAS BEEN INSTALLED IN THE MACHINE THE NUT

AND SPACER MUST BE REMOVED and saved for later use.

Open one of the safety covers on top of the machine and move

the bogie to be worked on into an easily accessible position.

TO AVOID INJURY WHEN MOVING IT BY HAND, ONLY

HANDLE IT BY THE ROUND AXLES OF THE LINK

SECTIONS.

Take a spare spacer and apply some MS grease to the thread of

the spring shaft and spacer face and push the spacer over the

open end of the shaft, small end first, followed by a M16 nut

(see fig. 2). NEVER USE A STAINLESS STEEL NUT,

because it will seize onto the shaft. Using a 24mm ring wrench,

tighten the nut until the spring has been compressed by about

3mm and the load is taken off the hinge pin. Using circlip

pliers, remove the circlip on the pin and pull out the pin. Lift

out the spring assembly.

Replace the spring in the reverse order. Apply some grease to

the pin before replacing it. Make sure that the protrusion on the

flange slips into the circular recess in the spring support.


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APPENDIX A: Using the Varispeed motor controller

(YASKAWA - J1000)

The motor controller is used to give the machine a soft start, control the

speed, protect the motor against overload and to indicate certain faulty

conditions on the machine.

1. Programming

The Yaskawa 1.5kW controller has a large number of

programmable parameters affecting its operation, each with a

factory default value. Some of these parameters have been

changed from the default values as indicated below. To change

any parameter value proceed as follow:

With the machine stationary, press the “V” key once. The

digital operator shows the parameter menu (PAR) then press

“ENTER” key. Press the “>” key to select the digit/parameter

you would like to change. Next use the “Ʌ” and “V” keys to select the parameter group, sub-group or number. Modify the parameter value using the “Ʌ” and “V” key and press the “ENTER” key to save the new value.

2. Basic operation

The motor speed is set as follows:

To adjust the speed, which is displayed in frequency units “Hz”,

adjust the “SPEED” knob in the orange control box marked zero

to ten.

Max. possible speed is set at 48 Hz, at which speed exactly 2

wheels per sec. passes a fixed point (7200 wheels per hour). If

you try to adjust the speed higher than 48Hz the display will

flash and go back to the previous saved value. When the light at

the LO/RE key is on (local/remote) then it is possible to run and

stop the machine by the “RUN” and “STOP” keys on the

controller itself. If the light is off then it is only possible by the

green and red buttons on the outside of the control unit.


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When the green RUN button on the outside of the control box is pressed

the motor speed will ramp up to the set speed in 5 sec.

When the red STOP button is pressed the motor speed will ramp down to

zero in 2 sec.

To display the motor speed first go to the main menu by using the

“ESC” key, then press the “Ʌ” key until the FOUT led is on. The display

now shows the actual drive output frequency in Hz. To see how it

changes stop the machine and restart it, you will see the speed moving

from zero to the set speed. To display the motor current press the “Ʌ”

key again. The “A” behind the value is the unit “Ampere”

3. Changing factory defaults

The following parameter have been changed from their factory default

values. Do not change any of these values before first consulting MLS

Test Systems. Please see section 1, Programming, which explains how to

change a parameter.

1.1 The acceleration time have been decreased from 10 sec. to 5 sec

and the deceleration time from 10 sec. to 2 sec. (Par. C1-01 = 5,

Par. C1-02 = 2)

1.2 Reverse running has been disabled. (Par. b1-04 = 1)

1.3 Remote control has been enabled (Start & Stop buttons) and

remote frequency control (Potentiometer) is enabled (Par. b1-02

= 1, Par b1-01 = 1)

1.4 The frequency at which max output voltage occurs was changed

from 60Hz to 50Hz. (Par. E1-04 = 50, Par. E1-06 = 50, Par E1-

07 = 1.3, Par E1-09 = 1.3)

1.5 The max. frequency have been set to 48 Hz. (Par. d2-01 = 96%)

1.6 Tripping on over torque has been enabled at 160% over 1 sec.

(Par. L6-01 = 4, Par. L6-02 = 160%, Par. L6-03 = 1s).


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APPENDIX B: The lateral displacement system

The purpose of the system is to spread the wheel loads on the pavement

in the lateral direction from the centreline of the track by moving the

entire machine. It consists of the following parts:

1. Two base plates that can be anchored to the pavement

2. Two “skate boards”. These fit under the adjustable legs of the

machine and each has four rollers that run on the base plates in a

lateral direction.

3. A small electric servo motor with a gearbox to drive the system.

The feedback potentiometer is mounted on the output shaft of

the gearbox inside a watertight cover.

4. An electronic control system that is mounted with the other

controls in the orange control box. The cable with the blue 3-

pin connector feeds current to the 12 Volt servomotor, while the

feedback signal runs through the cable with the small black 6-

pin connector.

The maximum displacement is 75mm (3”) to each side of the centre line.

This is infinitely adjustable down to zero by the multi-turn control knob

to the right of the counter in the control box. With a tire width of 80 mm

the total maximum track width is thus 230mm. Although the knob is

scaled from 0 to 100, it is only used up to a setting of 75.

To achieve a normal lateral distribution of the wheel loads, the wheels

spend more time near the centreline of the track than at the edges.

Displacement increments take place at constant intervals (about 25 sec.)

while the increments are varied to achieve the normal distribution. At

the maximum setting of the track width the wheels will spend about the

same time at each of the following distances from the centreline:

2.7mm, 8.5mm, 14.4mm, 20.7mm, 27.4mm, 36.1mm, 48.0mm and 75.0

mm. This approaches a normal distribution:

Y = (1/sqrt(2 * PI))* exp. (-z*z/2), with the 75mm position at z = 3.


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APPENDIX C: Maintenance checklist

The following checks are recommended for proper

maintenance of the MMLS3. If anything looks

suspicious, or is not fully understood, please contact the

manufacturers at the following e-mail address:

[email protected]

Reference:

For easy reference, devise a numbering system for the bogies, link

sections and guide wheels. The following is suggested:

Number the four bogies from 1 to 4 with a felt pen or otherwise, and do

the same with the four link sections. Refer to the guide wheels as left

front (LF), left centre (LC), right rear (RR) etc. Front would be

indicated by the direction in which the bogie normally runs. The right

hand rear guide wheel on bogie no. 3 would thus be referred to as B3RR

and the left hand centre wheel on link section no.2 would be L2LC, etc

Keep a record of measurements and observations.

Setting up for a test.

Before each series of tests, decide on the tire pressure and wheel load and

set the machine up as described in section 3. If the machine rocks on its

legs while operating, adjust any one of the four legs slightly up or down

until the rocking stops. Remember to lock the adjustable legs in

place.

Check that the tensions of the drum tension springs (see fig. 7) are set

correctly. The length of the springs, from outside to outside, including

the hooks, should be 130 ± 10mm.

Check the tension in the chain of bogies. Park a link section on the

upper guide rails (fig.1A). Hold down one axle with guide wheels onto

the guide rails and pull the axle next to that one upwards. You should be


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able to lift the wheels 40 to 50mm off the rails. If necessary, adjust one

or both of the two adjustable links between the bogies and link sections.

If the chain of bogies is too short, it pulls the drum towards the centre of

the machine, against the drum tension springs so that the drum may slip

because the guide wheels are not properly gripped between the drum and

the outer guide rails.

Maintenance checks:

1. Before commencing with a test, or every 400 000 axles or

once a week:

1.1 Check the tire pressure.

Compensate for temperature difference, if necessary. E.g. to

inflate a tire at 20ºC to obtain 700 kPa at 50ºC, the inflation

pressure, P, should be:

P = 700 x (273 ºC + 20 ºC) / (273 ºC + 50 ºC) = 635 kPa

Because the tires are small, losing only a small amount of air

can cause a significant drop in pressure. When using a hand

gauge to check the pressure, first slightly over inflate. Then let

small amounts of air escape between the valve and the gauge

until the correct pressure is reached. Then quickly remove the

gauge. Otherwise use a compressor with an inline gauge,

inflate slowly to the correct pressure and remove the connection

to the valve as fast as you can.

1.2 Inspect the rubber tires for cracks or other damage.

Some cracking is allowable. Observe the progress of cracks

from one check to the next.

1.3 Rotate the rubber wheels by hand and check for free rotation

and bearing noise.

1.4 Inspect all polyurethane wheels visually for damage to tread and

free rotation of bearings.


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1.5 Visually check that the bolts and nuts linking the bogies and link

sections together are not loose

1.6 Inspect the rubber stoppers on the bogie (see fig.2 or fig.3 in

manual) for cracks. Replace both stoppers if necessary

2. Every 1 000 000 axles

2.1 Measure and write down the diameters of all 48 guide wheels.

New wheels are 99mm diameter. Wheels on the same axle

should not differ by more than 0.5mm and the diameters should

not be allowed to reduce to under 95mm.

2.2 Measure and write down the width of each guide wheel.

New wheels are 33mm wide and should be replaced when

reduced to under 30mm.

2.3 Inspect the polyurethane tire of each guide wheel for cracks or

other damage.

Some cracks are allowable, but if bits of polyurethane starts to

break off, the wheel should be replaced. The centre wheels on

the bogies carries more load than the others. Wheels which

start to show signs of deterioration may be exchanged with

others in positions where less wear occur.

2.4 Check the spring centre pin bush on each of the 8 suspension

springs.

Refer to fig. 8. The left hand flange of the spring in the

drawing has a Vesconite bush through which the centre pin of

the spring slides. (The nut and spacer shown in the drawing

will normally not be there). The hole in the flange is larger

than the diameter of the centre pin, leaving a clearance of about

1.5mm all round the 16mm pin. If the bush wears, the pin may

touch the flange, wearing the pin. Check that the bush is in

place and that the pin does not touch the side of the hole.

2.5 Refer to section 4 and apply a small amount of grease to the

sidewalls of the guide wheels.


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2.6 Refer to section 4 and measure the gap between the upper guide

rail ends and the drive drum. If a feeler gauge is not available,

use two layers of office paper. If the gap is not correct, adjust

the drum as described. Afterwards make sure that the Bearing

Slide Assembly (fig. 7) is still free to move in the horizontal

direction.

2.7 Check the drive belts.

Remove the safety cover from the drive mechanism on the side

of the machine after removing the two M6 bolts at the top and

the two at the bottom of the cover. Check the outer and inner

drive V-belts for wear and cracks. Check the tension of the

outer belt and adjust if necessary.

3. Every 5 million axles:

In addition to the above, do the following:

3.1 Inspect the upper guide rail ends (fig. 6)

If the ends are worn to a sharp or cracked edge that may damage

the guide wheels, they must be removed and ground or filed

back to a blunt, smooth edge, about 0.5mm thick. Use

sandpaper to smooth it, if necessary.

Because the guide rail ends serve as reference for the position of

the drive drum, they must be replaced in exactly the same

position from which they were removed. Before undoing the

nuts that hold a guide rail end, measure with a feeler gauge and

note the size of the gap between the drum and the guide rail end.

When the guide rail end is replaced later on, make sure that the

gap is exactly (+/- 0.1mm) the same as before

3.2 Inspect the Vesconite guide rails for wear.

(Most wear normally occurs at the upper guide rail ends (see fig.

6 in manual)). Refer to the left hand drawing in fig M3-4-14A

below. The Vesconite strips are fastened with screws and

washers in the vertical direction, as indicated. The danger is

that the Vesconite may be worn away so far that the wheels


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make contact with the washer. The wheel will then be damaged

by the washer, creating sharp edges on the wheel which will cut

away more Vesconite. Make sure that there is at least 2mm

between the washers and the edge of the Vesconite where the

wheels run, over the entire length of the strips.

3.3 Check the hinge on the wheel guide

Refer to fig. 1B. The bottom end of the wheel guide is hinged

so that its tip can rest on the pavement, guiding the rubber wheel

smoothly down onto the pavement. Check for excessive free

play in the hinge. Remove the split pin on the hinge pin and

pull the hinge pin out. If worn, replace it with a new, greased

pin. Otherwise lubricate and replace the old pin.

3.4 Refer to section, "Aligning the drive drum" in the manual and

check the alignment of the drum.


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APPENDIX D: Circuit diagrams


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APPENDIX E: Technical Specifications

No. of bogies 4

No. of wheels 4

Wheel diameter 300mm

Tyre width 80mm

Lateral spread of track 0 - 75mm

Total track width 80 - 230mm

Nominal load per wheel 1900 - 2700 Newton

Tyre footprint area 34 cm2

Tyre contact pressure 750 kPa max.

Tyre model Vredestein 4.00-4 6PR V76

Tyre tube model Vredestein 4.00-4 TR87

Maximum speed 2.5 m/s

Maximum wheel loads/hour 7200

Supply Voltage 220 VAC Single Phase

Power consumption 1.5 kW

Drive belt type (V-belts) 13 x1080 (inner)

13 x 1480 (outer)

Dimensions

Length 2700 mm

Width 700 mm

Height 1200 mm

Weight 700 kg

Shipping weight 1000 kg

Specifications may be changed without notice


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Documents

MMLS3 OPERATOR’S MANUAL OPERATOR’S MANUAL The aim of the MMLS3 Operators Manual is to give information regarding safe and efficient techniques in operating the MMLS3. The machine