SAILTEC's Kobelt Hydraulische Steuerung Katalog - page 59

h y d r a u l i c s t e e r i n g a n d a c c e s s o r i e s
57
• It is important that the steering cylinders chosen for a specific
application are the right diameter and stroke suitable for the
installation.
• All of the Kobelt Steering Cylinders are equipped with either
ball rod end fittings or spherical bearings. These bearings and
rod ends have allowance for a given amount of misalignment
and rotation. It is very important that the cylinders are installed
without causing any binding in the cylinder mechanism during
operation.
• The bolts used for mounting the cylinder must be of Grade 5 or
better. The brackets used for fastening the cylinders must be able
to withstand the maximum torque of the cylinder and have a solid
plain face without any deflection during operation.
• The cylinders must be installed so that in the mid-stroke position
the ship’s rudder is in mid-position also. It is important that the
tiller arm is installed at right angles to the pivoting point of the
cylinder. If this is not followed, unequal rudder travel will result.
• When installing a twin or multi-cylinder steering system, it is of
extreme importance that the strokes of all cylinders are matched.
If, for example, one cylinder has reached the end of its stroke and
the second cylinder has not completed its stroke, it will cause a
tremendous amount of unnecessary stress on the rudder stock and
the steering system as a whole. It is extremely important that the
rod ends at the end of the cylinder and stopnuts are adjusted to
balance all cylinder movements.
• Steering cylinders connected to tiller arms move through an arc
when in operation. It is necessary to have hoses connected to the
steering cylinders for the hydraulic fluid. Solid piping will crack
and fail very rapidly because of the movement of the cylinders.
When selecting the hose, it is important to have the proper
operating range for these hoses to match the hydraulic system
pressure.
• On ships where there are two rudders interconnected with a tie
bar, the tie bar must also be constructed to take 60% of the total
rudder torque. It is highly recommended to leave sufficient room
in the steering gear compartment to allow for service. The Kobelt
Steering cylinders are also equipped with grease fittings which
should be greased at regular intervals (depending on the duty
cycle). Bolts, nuts and cotter keys should be checked regularly.
• Should anyone enter the steering gear compartment when
a hydraulic steering system is in operation, it is of extreme
importance to stay clear of all moving parts. A human limb could
easily be lost if due care and attention is not taken.
When installing a manual hydraulic steering system, it is
recommended to have a header tank above the highest steering pump.
On power hydraulic systems many options are available as far as the
location of tanks, filters, valving and, of course, a motor or engine-
driven pump. It is known to the trade that there is no valve that is
perfectly tight. Any hydraulic valve will lose a very small amount of oil
over an extended period of time and if the main tank is at the lowest
point, some oil from the highest point will drain to the lowest point. If
the steering system consists of manually-operated helm pumps, this
may cause the helm pumps to lose oil to the main tanks. If a large
enough header tank is installed, the main tank could be vented to the
header tank and then the uppermost station will never run out of oil.
Another approach would be to put the main tank above the highest
manual steering pump and run the suction line from the tank to the
pump and return line back to the tank. Another very popular system is
the autofill system whereby a continuous trickle of oil from the power
system fills the header tank with an overflow line from the header
tank back to the main tank. It is important to remember that the main
tank should always be above the pump so that there is gravity feed
from the tank to the engine or motor-driven pump.
7143 must be installed in all systems with spool valves.
I n s t a l l a t i o n I n s t r u c t i o n s f o r K o b e l t S t e e r i n g C y l i n d e r s
1...,49,50,51,52,53,54,55,56,57,58 60,61,62,63,64,65,66,67,68
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