3
KEYSTONE
FIGURE 79 PNEUMATIC ACTUATOR
OPERATING AND MAINTENANCE INSTRUCTIONS
DISASSEMBLY - DOUBLE ACTING UNITS
Note:
Please refer to the relevant exploded
views further on.
CAUTION
Remove all air pressure and observe normal
safety precautions including the use of eye
protection.
1. Pull off the indicator cap (item 17) from
the top of the actuator. If this cap is too
tight, light pressure may be applied to the
underside via a short length of round bar
or a similar blunt ended tool, inserted from
the bottom end of the actuator shaft. (Note:
levering with a screwdriver is considered
to be a potentially dangerous practice and
should be avoided.)
`The position relative to the shaft should
be noted to ensure correct position for
assembly.
2. Remove both travel stop bolts, if fitted
(items 19 to 22, see page 10 for all items)
3. Loosen endcap fixing screws evenly (item 15)
4. Remove endcaps (item 3)
5. Rotate output shaft (item 5) in a anti-
clockwise direction to drive pistons apart,
and remove pistons (item 2) complete with
backing pads/rings - if fitted.
6. Remove circlip (item 12) from bottom bore
of actuator.
7. Tap shaft downward and remove. Take care
to protect the actuator bore from possible
damage from the pinion gear teeth.
8. Remove top bearing (item 9) from the
actuator body (the bottom bearing
(item 6) will have been removed along with
the pinion shaft).
DISASSEMBLY - SINGLE ACTING UNITS
Note:
Please refer to the relevant exploded
views further on.
CAUTION
Remove all air pressure and observe normal
safety precautions including the use of eye
protection. Always ensure that spring return
actuators are in fail safe position before
attempting any maintenance. Pay particular
attention to this requirement when manual
operators are fitted.
For safety reasons DONOT ‘Air Assist’ Single
Acting Pneumatic actuators.
1. Pull off the indicator cap (item 17) from
the top of the actuator. If this cap is too
tight, light pressure may be applied to the
underside via a short length of round bar
or a similar blunt ended tool, inserted from
the bottom end of the actuator shaft. (Note:
levering with a screwdriver is considered
to be a potentially dangerous practice and
should be avoided.)
The position relative to the shaft should
be noted to ensure correct position for
assembly.
2. Remove both travel stop bolts, if fitted
(items 19 to 22, see page 11 for all items).
3. Loosen endcap/spring return housing fixing
screws (item 15) evenly until the spring load
is relaxed (3 - 5 mm).
Warning:
If, after loosening the screws
by 5mm there is still compression on the
spring pack, re-tighten the endcap screws
and return the unit to the factory for service.
4. Remove endcap/spring housing assemblies.
Warning:
Under no circumstances should
the spring retaining bolt be loosened or
adjusted without first consulting the factory.
5. Rotate output shaft (item 5) in an anti-
clockwise direction to drive pistons apart
and remove pistons (item 2) complete with
backing pads/rings - if fitted.
6. Remove circlip (item 12) from bottom bore
of actuator.
7. Tap shaft downward and remove. Take
care to protect actuator bore from possible
damage from the pinion gear teeth.
8. Remove top bearing (item 9) from the
actuator body (the bottom bearing (item
6) will have been removed along with the
pinion shaft).
