Universal Air Tools UT8955 - Manual (Page 2)

Operating
Select the correct screwdriver bit or fastener driver to suit the
screw or fastener to be tightened or loosened. Slide back the
sleeve (74) and insert appropriate drive bit.
This model has an adjustable clutch so that the torque applied
to the fastener can be adjusted to give the required tightness
within the torque range of the tool. To set the tool to give a
particular torque output, first remove the clutch housing - left
hand thread and pull out the clutch assembly being careful not
to lose guide pin and spring (32) and (31). Hold the clutch carrier
or insert a 1/4 hex Allen key into work spindle (84) and with a
spanner rotate adjustment nut (77) until it just touches sleeve
bearing (76). This is the clutch set at its lowest output level.
Reassemble the tool, try it on the joint to be fastened. If more
torque is required to place the fastener repeat the process but
rotate the adjustment nut (77) until there is a gap between it and
the sleeve bearing proceeding at approximately one turn of the
nut at a time until the correct tightness is achieved. If too high a
setting is reached rotate the adjustment nut back a part of a turn
at a time.
If the adjustment nut (77) is rotated too far along the clutch
spindle (84) it is possible that the clutch will not slip and a
reaction torque against the hands will be felt. In this situation, if
the fastener is not sufficiently tightened or cannot be loosened
then the tool in adjustable clutch mode has insufficient capacity.
Select a more powerful tool. The person setting up the tool must
be aware of this torque reaction at high setting levels of the
clutch and that the tool will try to turn against the hand. All that
is required is a firm grip.
The tool, when the stall torque position has been reached, can
still be used to set or loosen fasteners, provided the operator is
aware of the need to resist the torque reaction of the tool.
Further adjustment of adjusting nut (77) at this point will not
increase the output of the tool. The only thing that will affect the
output is a change in the air supply pressure. The output can be
increased up to the use of the maximum allowed supply
pressure and decreased with a reduction in supply pressure until
the tool fails to operate.
It must also be understood that even if the clutch is set to slip it
may not do so if the supply air pressure falls below the pressure
at which the clutch was set. It is therefore strongly
recommended that a pressure control valve is used. Information
as to suitable equipment can be obtained from your supplier.
When using the tool keep the screwdriver bit pressed firmly into
the screw head to avoid cam out and screw head damage.
Dismantling & Assembly Instructions
Disconnect from air supply.
Grip the tool in a vice fitted with soft jaws on the flats at the rear
end of motor housing (1) and unscrew clutch housing (75) - left
hand thread and take out the clutch assembly being careful not
to lose guide pin (32) and guide pin spring (31). Grip the clutch
and with a sharp pointed needle tool prise out retaining ring (71)
and take off washer (72), ball retaining spring (73) and ball
retainer (74) being careful not to lose bit retaining ball (83).
Again with a sharp pointed tool, remove a second retaining ring
(71) and pull off spacer (76). Unscrew adjusting nut (77) and pull
off spring seat (78), clutch spring (79) and thrust washer (80).
Remove from vice and tap the front end to remove 4 off balls
(81). Remove wiper (87) and then remove snap ring (85) and
separate clutch jaw (82) from work spindle (84). Remove a third
retaining ring (71) and pull off dog (86) from work spindle (22).
Unscrew lock ring (29) from motor housing (1). Grip the lock
ring and push out the internal assembly and separate bearing
(35), seal plate (33), internal gear (18), 3 off idler gears (20)
complete with 3 off idler gear bushes (21) and work spindle
(22). Idler gear bushes may be pressed out of idler gears (20)
but do not remove 3 off idler gear pins (19) from work spindle
(22).
Grip the end of rotor (26) and pull out the complete motor
assembly. Remove pin (28), motor gasket (44) and take off
retainer ring (38). Grip the spacer (27) and with a non metallic
or soft metal (lead or aluminium) hammer tap the splined end of
the rotor (26) to drive it through bearing (34) and end plate (23).
Remove cylinder (24) and take out 5 off rotor blades (25) from
rotor (26). Support the rear end plate (23) and tap the rotor (26)
through the rear plate (23) and bearing (34).
Pull the sides of hanger (42) apart to remove it from its retaining
holes. Drive out roll pin (40) and remove lever (2). Unscrew
bushing (10) complete with screen (11) and carefully prise out,
with a sharp needle pointed tool, deflector stop ring (8). Pull out
deflector (7) and prise out O-ring (9) from deflector (7). Remove
2 off screws (30) and pull off housing cap (12), muffler (41) and
housing gasket (13).
Unscrew valve screw (39) and remove O-ring (36), reverse valve
retainer (15), spring (16), plastic valve (4) and pin (3). Drive out
pin (45) to remove reverse valve bush (6), reverse valve (5),
spring (14) and push out valve bushing (17) if a replacement is
required.
Reassembly
Clean all components and examine for wear. Look in particular
for wear and cuts on O-rings, wear on rotor blades, gear and
clutch components.
Coat all parts with a pneumatic tool lubricating oil, one
preferably containing a rust inhibitor and grease all bearings,
gears and clutch parts with a molybdenum or lithium based
general purpose grease.
Before reassembling the motor, make sure that the faces of end
plates (23) that abut cylinder (24) are flat and free from burrs. If
necessary lap on a flat very fine grade of abrasive paper.
Reassemble in the reverse order.
When refitting the complete motor assembly to the motor
housing (1) first make sure that the motor assembly is clamped
tightly together and that the rotor spins freely, slide the motor
assembly, with gasket into the motor housing (1) ensuring that
motor pin (28) locates in the motor assembly and in the hole in
the bottom of the main bore of motor housing (1) situated
between the two main ports.
Reset the clutch as required and/or set the correct air pressure.
into the intake bushing 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.
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.
Page No 2
Safety Rules For A Screwdriver
1) Read all the instructions before using this tool. All operators
must be fully trained in its use and aware of these safety rules.
2) Do not exceed the maximum working air pressure.
3) Use personal safety equipment.
4) Use only compressed air at the recommended conditions.
5) If the tool appears to malfunction remove from use
immediately and arrange for service and repair.
6) If the tool is used with a balancer or other support device
ensure that it is fixed securely.
7) Always keep hands away from the working attachment fitted
to the tool.
8) The tool is not electrically insulated. Never use the tool if there
is any chance of it coming into contact with live electricity.
9) Always when using the tool adopt a firm footing and/or
position and grip the tool firmly to be able to counteract any