Improvements connected with the Lubrication and Prevention of Corrosion of the Propeller Shafts of Steam Ships, said Improve- ments being also applicable for other purposes.
Year: 1899

page_text: Date of Application, 13th May, 1899-Accepted; 1st July, 1899
COMPLETE SPECIFICATION.
Improvements connected with the Lubrication and Prevention of
Corrosion of the Propeller Shafts of Steam Ships, said Improve-
ments being also applicable for other purposes.
I, FRED LOBNITZ, of Clarence House, Renfrew, Scotland, Engineer and Ship-
builder, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
-
This invention relates to the lubrication and prevention of corrosion of the
propeller shafts of steam ships and it has for its object to provide simple and
efficient means whereby the tail shaft may be properly lubricated, the lubricant
conserved, and water, as well as sand and other deleterious substances, prevented
from gaining access to the tail shaft and its bearings.
The characteristic feature of my invention as compared with the devices for
the same purpose at present in use is that fluid pressure, preferably the pressure
of the lubricant itself, is utilized to force a movable protecting ring against a
working face on the propeller boss.
The features of novelty constituting the invention are pointed out in the
claims at the end of this specification.
In order that my said invention may be properly understood I have hereunto
appended two explanatory sheets of drawings, whereon,
Fig. 1 is a general view showing in longitudinal section the tail shaft of a ship's
propeller provided with my lubricating and protecting arrangements.
Fig. 2 is a vertical section showing one mode of carrying out the invention.
Fig. 3 is a cross section on the line Fig. 2.
Fig. 4 is a vertical section showing a slightly different mode of carrying out
the invention.
'
Fig. 5 is a cross section on the line Y-Y Fig. 4.
Referring to the drawings whereon the same reference numerals wherever
repeated indicate the same or similar parts.
1 is the propeller, 2 the propeller boss, the tail shaft, 4 the stern tube, 5 the
stern post and 6 the stern bulkhead.
In carrying out the invention according to the method illustrated at Figs. 1, 2,
and 3, I attach to the stern tube nut 7 or to the extreme end of the stern tube 4,
aft of the stern post 5, by means of screwed set pins 8 passed through the lugs 12,
a ring 9 having an annular groove 10 in it. This ring 9 can be made in halves
which can be secured together by means of bolts 11. The groove 10 is made very
accurately and into it is fitted, with a sliding fit, the movable protecting ring 13
which is provided at its inner edge with a leather or rubber cup ring 14 secured
in place by a brass ring 15 and screwed set pins 16, and, at its outer edge, with
a broadened working face 17. To the propeller boss a solid bearing ring 19
with a working face 20 is secured by means of screwed set pins 21. As will be
clearly seen a space for the lubricant is left between the inner peripheries of the
rings 9 and 19 and the periphery of the propeller shaft.

page_text: The protecting ring 13 can be prevented from revolving within the ring 9 by
usual means, such as a stopper pin 22 which is screwed through the outer wall of
the ring 9 and enters a slot 23 made in the ring 13. The slot 23 permits of the
ring 15 moving longitudinally so as to keep the faces bearing against each other
and allow for fore and aft motion of the shaft or wear of the faces.
Holes 24 are made at intervals apart in the ring 9 and these holes serve as
channels of communication between the interior passage 25 at the end of the
stern tube and the bottom of the annular groove 10. As the shaft runs slack
within the bush 27 the oil from the space 26 has free access to the passage 25.
The oil for lubricating the bearings and tail shaft is, preferably, supplied by
gravitation from a tank 28, placed in the engine room and provided.with a glass
gauge 29, by means of a pipe 30 which passes down to a three way cock 31
where it can be brought into communication with the pipe 32 leading to the
interior of the stern tube. The oil supplied from the tank, which latter should be
at such a height as to give the oil a pressure proportionate to the draught of the
vessel, say about 5 to 10 lbs. to the square inch, fills up the vacant space in the
stern tube and within the rings 19, 13, and 9 and also gains access through
the holes 24 to the groove 10, and, on account of its pressure, forces the ring 13
tightly against the face of the ring 19.
33 is a drain pipe leading from the stern tube and by means of which the oil
in the tube can be drained off and conserved when the bearings or the shaft are
being examined in dock.
36 is a protecting guard or casing which prevents floating objects, ropes, etc.,
injuring the device, and which is secured to the stern post by screw studs 36".
The modified arrangement shown at Figs. 4 and 5 practically differs from that
shown at Figs. 3 and 4 only by the use of a flexible rubber or leather protecting
ring 13 instead of the ring 13. The ring 13", as shown, may be tapered at
both sides and be adapted to fit on the one hand, into a tapered annular groove
made in the face of the ring 19" and, on the other hand, in a tapered groove
made in a ring 35 adapted to work within the groove 10. The ring 35 has the
cup ring 14 secured to it in the same manner as with the ring 13 of Figs. 2
and 3.
By preference I do not use ordinary metal fittings but allow the shaft, which is
not provided with the usual brass liner, to revolve in a bush, preferably made
of white metal, such as "lignite metal," which will not produce galvanic action,
and consequent excessive corrosion due to galvanic action, even should salt water
gain access to the shaft.
With the invention, as will be readily understood, the protecting ring 13
(or 13") is kept constantly pressed up against the face of the ring 19 (or 19") so
that the oil (or other suitable lubricant) within the ring forms a bath in which
the tail shaft revolves. The ring 19 (or 19") whilst preventing the egress of the
lubricant prevents the ingress of water, sand, etc., to the bearings. As the
ring 13 (or 13) wears away it is automatically fed forward by the fluid pressure
in the groove 10 but being lubricated this face has no more wear than the main
bearings of a marine engine.
If so desired the lubricant may be forced into the stern tube by means of an
ordinary form of automatic lubricating device, operated by mechanical means
actuated from the engines.
In some cases it may be thought desirable to utilize water pressure for pressing
forward the ring 13 (or 13") instead of the pressure of the lubricant and in such
cases one or more holes 37 (see dotted lines Figs. 2 and 4) would be made in the
ring 9 so as to open communication between the groove 10 and the sea water
outside. The sea water acting on the cup ring 14 would force the ring 13 (or 13")
against the ring 19 (or 19"). Of course in such cases there would be no holes 24
in the ring 9 so that the water could not mix with the lubricant or gain access
to the shaft.
In some cases a pipe might be fitted to the ring 9 so as to communicate with

page_text: its groove 10 and this pipe might be led up to a suitable reservoir, such as a
tank 28, for water or other fluid within the ship. In such cases the fluid, under
pressure due to gravitation or the action of a force pump, would act upon the
manner as the lubricant in the first
ring 13 (or 13") in precisely the same
described arrangement.
Generally speaking I prefer, however, to utilize the lubricant as the agent for
acting upon the ring 13 (or 13") as, when the outside water is used, the pressure
varies according to the draught of the ship; and, when a separate pipe connec-
tion is used between the tank 28 and the groove 10 such connection is less effective
and more complex.
When the outside water pressure or the oil pressure within the stern tube is
used the ring 9 could be arranged upon the propeller boss and the ring 19 upou
the stern post, the ring 13 working within the ring 9 as before.
The invention is applicable for protecting and lubricating the bearings of the
suction fans used for centrifugal pumps of suction dredging machinery and
generally where the invention may be found suitable for protecting the shafts
and bearings of machinery.
When the invention is adopted in a ship there will be no more wear or corro-
sion experienced with the stern tube bearing than with a main bearing of the
engine and the amount of lubricant used, which is small, is visible to the man
in charge in the gauge glass 29.
•
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
consider novel and desire to claim is:
1. A lubricating and protecting device of the character hereinbefore set forth,
in which the movable protecting ring is forced against a working face by means
of fluid pressure, substantially as herein before described.
2. The construction or general arrangement and combination of parts of the
device, substantially as herein before described and shown under two modifications
at Figs. 1 to 5 of the drawings annexed.
1
1141 of Nov 1899
H. D. FITZPATRICK,
Glasgow and London, Agent.