Universal Air Tools UT8055RB - Manual (Page 2)

Operating
The output of the impact wrench in prime working condition is
governed by mainly three factors
a) the input air pressure
b) the time the impact wrench is operated on the joint. Normal
time for joints of average tension requirement 3 to 5 seconds
c) the setting of the air regulator for a given joint at a given
pressure operated for a given time.
The air regulator item (19) can be used to regulate the output of
the impact wrench if no other control means is available. It is
strongly recommended that an external pressure regulator
ideally as part of a filter/regulator/lubricator (FRL) is used to
control air inlet pressure so that the pressure can be set to help
control the tension required to be applied to the threaded
fastener joint.
There is no consistent reliable torque adjustment on an impact
wrench of this type. However, the air regulator can be used to
adjust torque to the approximate tightness of a known threaded
joint. To set the tool to the desired torque, select a nut or screw
of known tightness of the same size, thread pitch and thread
condition as those on the job. Turn air regulator to low position,
apply wrench to nut and gradually increase power (turn regulator
to admit more air) until nut moves slightly in the direction it was
originally set. The tool is now set to duplicate that tightness,
note regulator setting for future use. When tightening nuts not
requiring critical torque values, run nut up flush and then tighten
an additional one-quarter to one-half turn (slight additional
turning is necessary if gaskets are being clamped) . For
additional power needed on disassembly work, turn regulator to
its fully open position. This impact wrench is rated a 3/8" bolt
size. Rating must be down graded for spring U bolts, tie bolts,
long cap screws, double depth nuts, badly rusted conditions
and spring fasteners as they absorb much of the impact power.
When possible, clamp or wedge the bolt to prevent springback.
Soak rusted nuts in penetrating oil and break rust seal before
removing with impact wrench. If nut does not start to move in
three to five seconds use a larger size impact wrench. Do not
use impact wrench beyond rated capacity as this will drastically
reduce tool life.
NOTE: Actual torque on a fastener is directly related to joint
hardness, tool speed, condition of socket and the time the tool
is allowed to impact.
Use the simplest possible tool-to-socket hook up. Every
connection absorbs energy and reduces power.
Dismantling and Assembly Instructions
Disconnect tool from the air supply.
Remove oil plug (2) with o-ring (7) and drain the oil contained in
the front end into a suitable container. Grip motor housing (1) in
a vice fitted with soft jaws and unscrew hose adaptor (15) and
remove exhaust deflector (14), valve spring (13), valve stem
(12), support rubber (11) and power silencer (10). Remove 4 off
screws with washers (33) and pull off steel housing (44)
assembly. Remove o-ring (47) and press out oil seal (46) and
anvil bushing (45) from housing (44). Lift out anvil (40) with anvil
spacer (41). Rubber ring (42) and socket ring (43) may be prised
off of anvil (40). Pull out remainder of hammer assembly and
separate into items hammer cage (34), cam ball pilot (35), cam
ball (36), hammer cam (37), 2 off hammer pins (38) and cam
release spring (39).
Remove 2 off springs (9) and pull out the complete trigger
assembly. Note that at this time how the groove in the end of
the trigger stem (3) has to locate around the end of the valve
stem (12). Remove ‘E’-ring (7) and pull trigger (3) out of the
throttle bushing (6). Remove stop cover (4). Remove o-rings (5)
from the throttle bushing.
Remove a further 4 off screws (33) from the rear end and prise
off end cap (17) with gasket (16) and air regulator reverse valve
(19), spring (20) and steel ball (21). Prise off ‘C’-ring (22) and
o-ring (18) from air regulator reverse (19) and push out air
regulator reverse (19) from end cap (17) being careful not to
lose stop pin (21) and spring (20) which may spring out as air
regulator reverse is removed. Carefully tap the splined end of
rotor (25) to drive out the complete motor assembly from the
rear end of motor housing (1). Remove motor guide pin (28) and
pull rear end plate (24) assembly and front end plate (32)
assembly from rotor (25). Remove cylinder (27) and 6 off rotor
blades from rotor (25).Tap out ball bearing (23) from rear end
plate (24) and remove o-ring (31) and tap out ball bearing (29)
and oil seal (30) from front end plate (32).
Reassembly
Clean all parts and examine for wear, cracks etc. and replace
parts as necessary. Look in particular for wear and cuts on
o-seals and o-rings and for wear and cracks on rotor blades
(26), hammer cage (34), cam ball pilot (35), hammer cam (37)
2 off hammer pins (38) and anvil (40) particularly in the area of
the square drive. Make sure that the faces of end plates (24) and
(32) that abut cylinder (27) are flat and free from burrs and
surface defects and if necessary lap faces on a flat find abrasive
surface. Use only manufacturer or distributor supplied
replacement parts. Lightly coat all parts with a suitable
pneumatic tool lubricating oil and assemble in the reverse order.
On completing assembly ensure that all parts are locked tight
and that the anvil (40) is free to rotate and the trigger and
reverse/air regulator mechanisms operate freely. Remove oil
plug (2) and o-ring (7) and pour into the front end 3/8 fluid oz.
(12cc) of a standard SAE20 oil. Replace oil plug and o-ring. Do
not overfill with oil as this could reduce the power of the tool.
With trigger (3) depressed, pour into hose adaptor (15) 5ml (1
teaspoonful) of a suitable pneumatic tool lubricating oil. Release
trigger and connect to a suitable air supply and run tool slowly
for 2 to 3 seconds to allow the oil to circulate and set tool for
the operation required - see Section Operating.
pressing the trigger on the tool. Disconnect the air line and pour
into the hose adaptor a teaspoonful (5ml) of a suitable
pneumatic motor lubricating oil preferably incorporating a rust
inhibitor. Reconnect tool to air supply and run tool slowly for a
few seconds to allow air to circulate the oil. If tool is used
frequently lubricate on daily basis and if tool starts to slow or
lose power. When lubricating, also ensure that screen in hose
adaptor (15) is clean.
It is recommended that the air pressure at the tool whilst the
tool is running is 90 p.s.i./6.3 bar. The tool can run at lower and
higher pressures with the maximum permitted working air
pressure of 100 p.s.i./7.0 bar. For a lower air pressure the tool
will give a lower output for a given setting of the air regulator set
for 90 psi operation and an increased output for higher
pressures. Hence it is possible that changes in supply pressure
can give situations where the fastener is under or over
tightened. For changes in pressure, the regulator position and
application should be reassessed.
It is recommended that joint tightness of the threaded fastener
assembly be checked with suitable measuring equipment.
Page No 2
Safety Rules When Using an Impact
Wrench
1) Read all the instructions before using this tool. All operators
must be fully trained in its use and aware of these safety rules.
All service and repair must be carried out by trained personnel.
2) The socket used must be of the correct drive size and the
"impact" type. Never use sockets other than impact type.
3) Do not use sockets with excessive wear to the input and
output drives. Check that the square on any other type of drive
or the impact wrench is not cracked or excessively worn before
fitting or changing socket, extension, etc. Make sure that the
socket is firmly fixed to the tool.
4) Always ensure that a stable position or footing is adopted
before using the tool.
5) Ensure that the tool has been correctly set up on a test joint.
Incorrect set up could cause joint breakage with sudden and
unexpected movement of the tool.
6) Use only correct spare parts for repair.
7) Always ensure that the reverse valve is in the correct position