LAWSON ENGINEERS LTD Ref : PJ1682
Issue Date : 06.06.2006
A temperature sensor is fitted to the gearbox oil circuit. This is set to shut down the HPU
at a temperature of 90°C
6.4 A-FRAME
Controlled by proportional joystick on Remote Box. The same joystick controls the leg
extension and the leg luffing motions. There is a selector switch to choose between the
two motions. Joystick operates, Pull to luff in (or retract legs), push to luff out (or extend
legs).
When operating the A-frame always ensure there is enough slack in the umbilical to
allow the range of movement you require.
The winch & A-frame can be used simultaneously, although at reduced speeds.
Never
drive the A-frame against a tight umbilical. There is also an overload protection
facility. This is controlled by a loadcell that supports the sheave. Once the tension in the
umbilical rises above the set point an alarm sounds and further movement of the A frame
outboard is impossible. The pre-alarm is set at 5Te umbilical tension. The alarm and trip
is set at 6Te. However due to inertia and time delay as the trip operates the tension in the
umbilical can rise to 10-12Te before the ‘A’ Frame ceases movement. For this reason it is
good practice to always keep the umbilical slack.
The umbilical tension readout is set to be accurate when the ‘A’ Frame is fully outboard.
There will be an error in the reading when inboard.
Do not operate the A-frame with the snubber damping locked.
Do not operate the A-frame unless the R.O.V. is aligned correctly.
Never
lower the vehicle onto the deck using the a-frame luffing cylinders or the
telescopic legs – only use the snubber raise/lower function to achieve this. Failure to
comply could easily result in the vehicle being crushed against the deck.
6.5 SNUBBER
Controlled by Pushbuttons on the Remote Box as follows:
Latch
Toggle switches to control opening and closing. The
latches are spring returned, as well as positively
returned by Toggle switch control. There are visual
mechanical indicators on the snubber as well as lights
on the control desk. Both latches have to be open or
closed for the lights to shine.
- 23 -
