Improvements in Propeller Shafts for Marine Engines.
Year: 1894

page_text: Date of Application, 15th Oct., 1894
Complete Specification Left, 15th July, 1895-Accepted, 21st Sept., 1895
PROVISIONAL SPECIFICATION.
Improvements in Propeller Shafts for Marine Engines.
I, DONALD BARNS MORISON, of Hartlepool Engine Works, Hartlepool, in the
County of Durham, Engineer, do hereby declare the nature of this invention to
be as follows:-
As is well known, with steamship propeller shafts of the usual construction
comprising a plain shaft of iron or steel on which are shrunk brass cylinders tubes
or liners forming the bearing surfaces in the stern tube, the liners terminate in
planes at right angles to the axis of the shaft, and at the ends of the liners galvanic
action produces, in the shaft proper, local corrosion in such a manner as to seriously
weaken the shaft so that it is liable to be rendered inoperative through fracture.
Now my invention is designed to mitigate this serious ovil.
For this purpose the ends of the liners according to my invention are made to
terminate not each wholly in a plane at right angles to the axis of the shaft, but in
a toothed, zig-zag or notched form such that assuming the shaft itself to be in two
parts divided in a like direction then there would be projecting portions of each
part taking into corresponding recesses in the other. The form and number of
projections on the end of a liner may obviously be varied within wide limits without
departure from the essential characteristic of my invention.
In order to maintain the joint between the projections of the liner and the shaft
1 sometimes connect the said projections by a ring whose outer diameter corresponds
to the outer diameter of the liner, but the inner diameter of the ring is greater
than the diameter of the shaft so as to leave spaces between the ring and the shaft
which may be filled with protective material. The ring may be formed with
or independent of the liner, and may be pinned to the liner or to the shaft as
desired.
CUMI LEMIE DIECITATION
Improvements in Propeller Shafts for Marine Engines.
I, DONALD BARNS MORISON, of Hartlepool Engine Works, Hartlepool, in the
County of Durham, Engineer, 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 :-
As is well known, with steamship propeller shafts of the usual construction
comprising a plain shaft of iron or steel on which are shrunk one or more brass
cylinders, tubes or liners (hereinafter called liners) forming the bearing surface or
surfaces in the stern tube, the liner or liners terminates or terminate in planes at
right angles to the axis of the shaft, and at the end or ends of the liner or liners
exposed or liable to exposure to the action of sea water, galvanic action produces,
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page_text: To the shaft proper, local corrosion in such a manner as to seriously weaken the
shaft, so that it is liable to be rendered inoperative through fracture.
Now my invention is designed to mitigate this serious evil. For this purpose
1 form the end or ends of the liner or liners. that is or are exposed to the action of
sea-water, in the manner 1 will now proceed to explain by the aid of the
accompanying drawings wherein,
Fig. 1 is a perspective view of a propeller shaft provided with liners according
to this invention.
Figs. 2 and 3 are perspective views to a larger scale than Fig. 1, showing end
portions of the liners.
Figs. 4 to 8 inclusive are developed views showing the inner surfaces of portions
of liners having different forms and numbers of end projections.
The outer exposed ends of the liners a, a fixed upon the propeller shaft b
(Fig. 1) are, according to my invention, each made to terminate, not wholly in a
plane at right angles to the axis of the shaft as heretofore, but in a toothed, zig-
zag or notched form, as shown for example at e in Figs. 2 and 3. This formation
of the end of the liner is obtained by forining such liner end with projections a
which are kept in close contact with the surface of the shaft, so that the dividing
line between the portion of shaft and the end of the liner exposed, or which may
be exposed, to the action of the sea water when in use, and at which dividing line
local corrosion takes place, will not be located wholly or mainly in a plane at right
angles to the axis of the shaft, but in a line offering greater resistance, thereby
reducing the liability to fracture resulting from the weakening of the shaft by
such local corrosion. The stress on the material of the shaft at the liner ends is.
also not so local as in the ordinary form, and therefore is not so liable to produce
intense local corrosion, even if the shaft is exposed directly to the action of sea
water.
In order to maintain the joint between the projection a! of the liner a and the
shaft b, I prefer to connect the said projections by a ring d whose outer diameter
corresponds to the outer diameter of the liner, but the inner diameter of the ring is
greater than the diameter of the shaft so as to leave recesses or spaces between the
ring, projections and shaft through the openings e which may be filled with
suitable protective material such as gutta-percha or clastic cement. The ring d
may be formed in one with the liner, as in Figs. 12 and 3, or independent thereof,
in which latter case it may be pinned to the liner, or to the shaft, as may be
desired.
At the outer end of the liner, next the propeller, the free ends of the pro-
jections a¹ may advantageously terminate within the ring d, as shown in Fig. 2, so
that the filling material or cement inserted within the aforesaid recesses. is connected
between each two recesses, thus forming a continuous body, aud in the event of
this liner being continuous within the stern tube, the outer end thereof next to the
propeller would be the only end to which my invention could advantageously be
applied.
The form and number of the projections a' on the end of a liner may obviously
be varied within wide limits without departure from the essential characteristic of
my invention. Thus Figs. 4 to 8 inclusive are developed or flattened out views
showing the inner surfaces of portions of liners having different forms.and numbers
of projections.
Fig. 4 shows the expanded view in plan of one half of a liner end, so that the
dividing line between the end of the liner and the shaft would be in two planes
inclined to the axis of the shaft, or as a modification of this the dividing line might
be in one plane in which case the single tooth would require to be pinned to the
shaft. In Fig. 5, there are in the complete ring four projections with rounded
ends terminating inside the outer end of the ring d. In Fig. 6, the projections are
of angular form as in Fig. 5, but their ends are less rounded, and terminate Aush
with the outer end of the ring d. In Fig. 7, there is no connecting ring d, the
ends of the projections a' being each formed with a hole a' through which a' fastening

page_text: device, such as a screw, can be passed for holding the end down closely upon the pro-
peller shaft. In Fig. 8, the end of the liner is of corrugated form, the projections a'
thus formed being more numerous aud of less length than those shown in the other
constructions.
Having now particularly described and ascertained the nature of the said inven
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A propeller shaft provided with a liner or liners in or each in the form of a
tube or hollow cylinder whereof the end or ends exposed or liable to exposure to the
action of sea water, is or are made to terminate in a toothed, zig-zag or notched
form such as bereinabove described, so that a line of corrosion formed at the
dividing line between the shaft and an exposed liner end will not be located wholly
or mainly in a plane at right angles to the axis of the shaft.
2. A propeller shaft of the kind referred to in the preceding claim wherein the
liner end projections (where there are two or more) are connected and maintained in
contact with the shaft by a ring whose outer diameter corresponds to that of the
liner but whose inner diameter is greater than that of the shaft so as to leave
recesses or spaces adapted to receive filling material, substantially as herein
described.
3. Constructing propeller shafts with liners whereof the end or ends exposed or
liable to exposure to the action of sea water is or are as illustrated' and as described
with reference to the several examples Figs. 1 to 3 inclusive, Fig. 4, Fig. 5, Fig. 6,
Fig. 7 and Fig. 8 of the accompanying drawings so formed as not to terminate
wholly in a plane at right angles to the shaft.
Dated. this 15th day of July 1895.