Frank COBRA C User manual

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever

© 2006
Reproduction on whole or in part requires written permission from
Hermann Frank GmbH & Co. KG, 75038 Oberderdingen, Germany.
All rights reserved.
No liability for any damage arising from the use of this brochure.
Subject to alterations.
Hermann Frank GmbH & Co. KG
Östliche Bahnhofstraße 8
75038 Oberderdingen
Germany
Tel.: [phone] / 60 88-0
Fax: [phone] / 60 88-11
[email protected]
www.hermannfrank.de
State: January 2006

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This brochure uses the symbol to mark important instructions for safety and preventing damage.
Please give special attention to the marked instructions.
They refer to a potentially dangerous situation. Failure to comply can result in fatal or severe injuries and
damage to property.
Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
Contents
1 Introduction.................................................................................................................................... 6
2 Scope of delivery........................................................................................................................... 7
3 Machine specifications COBRA C .............................................................................................. 8
3.1 Important components..................................................................................................................... 8
3.2 Technical data ................................................................................................................................. 9
3.3 Safety and machine protection facilities .......................................................................................... 9
4 Proper use...................................................................................................................................... 9
5 Installing the guide tube .............................................................................................................. 10
6 Disassembling for transport ........................................................................................................ 11
6.1 Removing the guide tube ............................................................................................................... 11
6.2 Removing the motor ........................................................................................................................ 12
7 Operating the COBRA C ............................................................................................................. 14
7.1 Protective clothing and equipment ................................................................................................ 14
7.2 Fitting the dust bag ....................................................................................................................... 15
7.3 Safety instructions regarding dust .................................................................................................. 16
7.4 Disposing of sanding dust ............................................................................................................. 17
7.5 Replacing the sanding belt ............................................................................................................ 18
7.6 Adjusting the sanding pressure ..................................................................................................... 19
7.7 Safety instructions for electric cable and connectors .................................................................... 20
7.8 Connecting the COBRA C to the mains power .............................................................................. 20
7.9 Remarks about sanding parquet and plank floors ......................................................................... 22
7.10 Sanding with the COBRA C ........................................................................................................... 25
8 Maintenance .................................................................................................................................. 30
8.1 Changing the sanding drum .......................................................................................................... 30
8.2 Adjusting the running wheels ......................................................................................................... 32
8.3 Adjusting the castor wheels ........................................................................................................... 34
8.4 Adjusting the tension roller ............................................................................................................. 35
8.5 Tightening the V-belts...................................................................................................................... 36

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9 Parts lists ......................................................................................................................................... 37
9.1 Parts list of chassis ......................................................................................................................... 37
9.2 Parts list of motor ............................................................................................................................ 42
9.3 Accessories ..................................................................................................................................... 44
Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever

6
Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
1 Introduction
Dear customer,
you have decided in favour of the FRANK parquet floor sander COBRA C, the correct choice with
respect to quality and performance.
The COBRA C is the result of a consistent implementation of many years of experience.
This machine combines an extraordinary high sanding performance and an excellent sanding
quality, together with an easy to operate, proven and reliable technology.
This operating instructions contain important informations for the use and safe operation of the
COBRA C.
Caution!
Read these operating instructions carefully before assembling or operating the
COBRA C. Ensure that all operators read these operating instructions prior to operate the
machine.
Adherence to the safety notes helps to protect against potential dangers for health and
personal safety and to prevent an improper utilisation of the machine.
Before starting to work, make yourself familiar with the operation of the machine. It's too late
if you do it while working!
Never allow anybody without sufficient skills and knowledge to operate the machine.

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7
2 Scope of delivery
1 guide tube
2 dust bag
3 cable with plug and coupling
4 lower part of the machine with motor
5 wing screws (2 pieces)
6 operating instructions
7 hexagon socket screw key 5 mm
8 hexagon socket screw key 6 mm
9 hexagon socket screw key 10 mm
10 running wheel adjusting tool
11 tool pouch
12 fork wrench 10 mm
13 fork wrench 13 mm
14 fork wrench 24 mm
15 double fork wrench 30/36 mm
16 hearing protectors
17 respirator
18 Multiclip

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
3 Machine specifications COBRA C
3.1 Important components
1 pressure regulating screw 11 bumper wheel
2 castor wheels 12 belt guard
3 running wheels 13 motor
4 drum cover 14 switch box
5 V-belt tension screw 15 dust bag
6 tension lever 16 cable arm
7 knurled nut 17 left hand grip
8 clamping lever 18 main lifting lever
9 motor plug 19 right hand grip
10 carrying handle 20 gentle lifting lever

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
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3.2 Technical data
Single-phase AC motor 230 V, 50 cps
Motor power 2500 W
Sanding drum speed 2100 rpm
Sanding width 200 mm
Sanding belt dimensions 200 mm x 750 mm, endless
Machine weight 78 kg
3.3 Safety and machine protection facilities
COBRA C is equipped with an
-overcurrent cutout and an
-no-volt release
The overcurrent cutout protects the machine from damage and persons from endangering in the
case of short circuits.
The no-volt release prevents uncontrolled restart of the machine after power failure. The motor
will not restart automatically when the power returns, it will have to be switched on again.
4 Proper use
The parquet floor sander COBRA C is suitable for dry sanding of parquet and plank
floors. No other use is allowed.
Caution!
Never use COBRA C for wet procedures (mortal risk from electric shock)!

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
5 Installing the guide tube
Note: The COBRA C is delivered with the guide tube (1) removed.
Caution!
Injury to the operator or other persons could occur or damage could occur if the machine
starts up unintentionally. Disconnect the machine from the power supply before working
on the machine!
Instructions:
1. Insert the guide tube (1) into the guide tube support (7). The curved section of the tube must
face toward the motor. Clamp the guide tube by means of the clamping lever (6) located on
the guide tube support.
2. Position the pair of bores in the control rod connector (8) over the pair of bores in the control
rod (5). The control rod connector has to lie close on the right side of the control rod. Screw
together the parts with the two wing screws (4).
3. Move the main lifting lever (2) into the rear position to raise the sanding drum from the floor.

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
11
6 Disassembling for transport
For easy transportation the motor and the guide tube can be removed.
6.1 Removing the guide tube
Caution!
Injury to the operator or other persons could occur or damage could occur if the machine
starts up unintentionally. Disconnect the machine from the power supply before working
on the machine!
Instructions:
1. Fold down the cable arm (3).
2. Move the main lifting lever (2) to the front position in order to lower the sanding drum to the
floor. This removes the load from the control rod (5).
3. Loosen both of the wing screws (4) to detach the control rod (5) from the control rod
connector (8).
4. Open the guide tube support (7) with the clamping lever (6) and pull the guide tube (1) out.

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
6.2 Removing the motor
Caution!
Injury to the operator or other persons could occur or damage could occur if the machine
starts up unintentionally. Disconnect the machine from the power supply before working
on the machine!
Instructions:
1. Make sure that the motor switch is in the off position and that the mains cable is
disconnected from the motor plug.
2. Unscrew the knurled nut from the belt guard and open the belt guard.
3. Loosen the lock nut (2) on the belt tension screw.
4. Turn the belt tension screw (1) counterclockwise. This will lower the motor and release the
tension on the belts.
5. Remove the belts.

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
6. Remove the knurled nut from the motor bracket.
7. Now you can remove the motor.

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7 Operating the COBRA C
7.1 Protective clothing and equipment
Caution! Wear hearing protectors!
The supplied hearing protectors must be worn when using the machine.
The following sound level values have been measured for the parquet floor sander COBRA C
according to DIN 45 645:
Idle mode LEQ = 85 dB(A)
Working mode LEQ = 87 dB(A)
The noise produced when the machine is working depends on various factors. Local
conditions such as room size and quality of the floor affect noise development.
Caution! Wear a respirator!
When using the parquet floor sander COBRA C and when disposing of the sanding
dust, always wear a respirator (see chapter 7.3 and 7.4). Wear the respirator which is
supplied with the accessories.
Caution! Wear safety goggles!
When using the parquet floor sander COBRA C and when working on COBRA C,
always wear safety goggles to protect your eyes.
Caution! Wear proper working clothing!
When using the parquet floor sander COBRA C and when working on COBRA C, never
wear loose clothing. This can get caught up in moving parts.

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7.2 Fitting the dust bag
Caution!
Only use original FRANK dust bags for the parquet floor sander COBRA C.
Caution!
The dust bag must be firmly fitted to the dust pipe before sanding.
Instructions:
1. Pull the dust bag over the dust pipe to behind the pipe reinforcement.
2. Fasten the dust bag here using the Multiclip.
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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7.3 Safety instructions regarding dust
Caution! Ultra-fine sanding dust!
Always wear a respirator when sanding parquet and plank floors (is included with the
accessories).
When the machine is used for its proper purpose, the sanding of wooden floors naturally
produces dust. The machine has an integrated dust collecting system which blows the dust into
the dust bag. The dust is collected in the dust bag. Even so, this cannot prevent fine and
ultra-fine dust being produced when using the machine.
Caution! Health risk!
Wood dust, particularly when treated with impregnating agents, solvents and coatings,
can cause allergic reactions (e.g. of the skin or respiratory system) after a sensitization
period. Beech and oak dust is classified as being carcinogenic (cancer of the nasal
mucous membranes). Dust from other kinds of wood is suspected of having a
carcinogenic effect.
Caution! Fire risk!
No smoking while sanding!
All ignition sources are prohibited in rooms where sanding work is being carried out!
Air the rooms thoroughly.
Together with an ignition source and the oxygen in the air, wood dust can cause fires and
explosions.
Caution! Fire risk!
Sanding over metal parts such as nails can produce sparks which are blown into the
dust bag together with the wood dust. Here the glowing metal chips can still cause a fire
even hours later.
Every time after the machine has stopped and at the end of working, the sanding dust
contained in the dust bag must always be disposed of immediately in a fire-proof,
non-flammable container. The container must be covered with a fire-proof,
non-flammable lid. Store the container only outdoors.

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
17
7.4 Disposing of sanding dust
Caution! Fire risk!
Because of the fire risk, the sanding dust contained in the dust bag must always be
disposed of immediately every time after the machine has stopped and at the end of
working. The sanding dust must be disposed of immediately in a fire-proof,
non-flammable container. The container must be covered with a fire-proof,
non-flammable lid. Store the container only outdoors.
Caution!
At the latest when 1/3 full, the sanding dust contained in the dust bag must be disposed
of, because the dust collecting capacity is reduced when the bag is any fuller. The
sanding dust must be disposed of in a fire-proof, non-flammable container. The container
must be covered with a fire-proof, non-flammable lid. Store the container only outdoors.
Caution!
Always wear a respirator when disposing of the sanding dust (included with the
accessories).

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7.5 Replacing the sanding belt
Caution! Danger from machine starting up!
When replacing the sanding belt, there is a risk from the machine starting up
unintentionally. Always disconnect the parquet floor sander from the mains power before
working at the sanding belt.
Caution! Risk of cutting your hands!
The sanding grains of the sanding belt have sharp edges. Always wear safety gloves
when replacing the sanding belt.
Instructions for replacing the sanding belt:
1. Switch the machine off.
2. Disconnect the machine from the mains
power.
3. Open the sanding drum cover (1).
4. Move the tension lever (2) forward. The
sanding belt which was held under tension
is now released. Pull it out to the side.
5. Insert a new sanding belt.
6. Clamp the new sanding belt by moving the
tension lever (2) backward.
7. Close the sanding drum cover (1).

Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
19
7.6 Adjusting the sanding pressure
Use the pressure regulating screw to adjust the required sanding pressure.
High sanding pressure:
Turn the pressure regulating screw inwards as far as it will go.
Medium sanding pressure:
Turn the pressure regulating screw outwards to the upper marking (1) on the screw thread.
Low sanding pressure:
Turn the pressure regulating screw outwards to the lower marking (2) on the screw thread.
1
2

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Operating instructions
Parquet floor sander COBRA C
with gentle lifting lever
7.7 Safety instructions for electric cable and connectors
Caution! Mortal risk from electric shock!
There is a mortal risk from electric shock if the machine is used when the electric cable
or connectors are damaged. If the electric cable and connectors are damaged, they must
be replaced by a qualified electrician.
Caution! Mortal risk from electric shock!
Running over the electric cable with the sander entails a mortal risk from electric shock!
Never point the machine towards the cable!
7.8 Connecting the COBRA C to the mains power
Caution!
Avoid the risk of a serious accident from a fault current and use a portable RCD (Residual
Current Protective Device). The portable RCD (Residual Current Protective Device) has to
be in compliance with the valid regulations and standards. Consult a licensed electrician.
The portable RCD (Residual Current Protective Device) must be checked every time
before it is used.