Blohm + Voss Oil Tools GraySpin Mark 40, Technical Documentation Manual

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The GraySpin Mark 40 has been designed with the ease of repair as an important feature.
The Mark 40 is comprised of modular components so that any problem can be easily
detected. Every component can be either repaired or replaced in the field keeping down
time to a minimum.
Chain (9G8000)
The double pitch chain that drives the Mark 40 has been overdesigned to insure longevity.
If the chain must be removed in order to replace drive rollers, speed reducer assembly, or
idler sprocket, the following procedures are recommended:
Initial Steps to Installing or Removing the Chain
1. Make sure the Mark 40 is off the drill pipe connection and in rest position on the derrick.
2. Shut down the supply of power from the source or from the shut off valve.
3. Bleed any air pressure from the Mark 40 by cycling the door valve. Make sure the doors
are fully open.
4. Disconnect the Mark 40 from the power
source.
5. Assume that there is still a load on every
actuator. Proceed with caution.
Chain Removal
The chain used in the Mark 40 is a cottered
type chain. Any link may be used as a
master link; however, in most instances the
original master link is facing down. Locate
this link in the middle of the visible portion
of the left hand drive roller by engaging the
motor.
Loosen the four
3/4
” hex head capscrews
attaching the speed reducer assembly to the
top of the spinner case and slide forward.
Remove the master link. The chain can be
easily unthreaded with the exception of the
motor sprocket. Pull the chain through the
most rear position of the motor sprocket
avoiding contact with the sprocket.
Figure 12
Figure 13