Improvements in Covers or "Liners" for Screw Propeller Shafts.
Year: 1899

page_text: Date of Application, 29th Mar., 1899
Complete Specification Left, 28th Dec., 1899-Accepted, 10th Feb., 1900
Improvements in Covers or "Liners" for Screw Propeller Shafts.
I, JOHN LYALL, Superintendent Engineer of The Clan Line Steamers, Limited,
109, Hope Street, in the County of Glasgow, North Britain, do hereby declare the
nature of this invention to be as follows, that is to say:-
•
My said invention has for its object to improve the construction of covers or
"liners" for screw propeller shafts.
In screw propeller shafts as hitherto constructed what is known as the tail end
shaft is fitted with a cover or liner of gun metal on the parts which turn in the
inner and outer bearings in the stern tube when the shaft is in its place. The
part of the tail end shaft between these two liners 'is either left uncovered or fitted
with another liner which is brazed or otherwise jointed to the other two liners.
It has been found from experience that any water in the stern tube acts on the
middle part of the tail end shaft either directly when that part is left uncovered
or through time through the joints of the liners which open owing to unequal
expansion of the metal, the water corroding the shaft and if not noticed in time
so weakening it that it breaks when in use and causes serious accidents.
To remedy this defect I, according to my invention, fit the tail end shaft with
a liner, by preference, of gun metal extending the whole length of the stern tube.
This liner is, by preference, cast with its middle part thinner than the two end
parts so that when in position that part will not bear on the shaft. The middle
of the liner is also made of either a corrugated, ribbed, or similar form so that
when heated and being shrunk in position on the shaft and also afterwards when
the shaft is working the corrugations allow for expansion or contraction of the
two end parts of the liner thus preventing the possibility of the liner becoming
fractured and permitting the water getting access to and corroding the shaft.
Dated this Twenty-eighth day of March 1899.
Improvements in Covers or "Liners" for Screw Propeller Shafts.
I, JOHN LYALL, Superintendent Engineer of The Clan Line Steamers, Limited,
109, Hope Street, in the County of Glasgow, North Britain, 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, that
is to say:-
:-
My said invention has for its obiect to improve the construction of covers or

page_text: In screw propeller shafts as hitherto constructed what is known as the tail
shaft is fitted with a cover or liner of gun metal on the parts which turn in the
inner and outer bearings in the stern tube when the shaft is in its place. The
part of the tail shaft between these two liners is either left uncovered or fitted
with another liner which is brazed or otherwise jointed to the other two liners.
It has been found by experience that any water in the stern tube acts on the
middle part of the tail shaft either directly when that part is left uncovered or
through time through the joints of the liners which open owing to unequal expan-
sion of the metal, the water corroding the shaft and if not noticed in time so
weakening it that it breaks when in use and causes serious accidents.
To remedy this defect I fit the tail shaft with a liner, by preference, of gun
metal extending the whole length of the stern tube. This liner is, by preference,
cast with its middle part thinner than the two end parts, the middle part being
also made of a corrugated or similar form.
And in order that my said invention and the manner of performing the same
may be properly understood I hereunto append a sheet of explanatory drawings
to be hereinafter referred to in describing my improvements.
Figure, 1, on the drawings is an elevation of a portion of a tail shaft as fitted
with my improved liner, the liner being in section; and Figure, 2, is a longitu-
dinal section of a stern tube showing the tail shaft and liner in elevation, this
figure being drawn to a smaller scale than Figure, 1. In these drawings the
same reference letters are used to mark the same or like parts wherever they are
repeated.
As shown in the drawings the tail shaft, A, in the stern tube, B, is fitted with
a linner by preference of gun metal extending the whole length of the stern
tube, B. This liner is, by preference, cast with its middle part, C, thinner than
its two end parts, D, E, which turn in the inner and outer bearings, F, G, in the
stern tube, B, so that the middle part, C, does not bear on the shaft, A. The
middle part, C, of the liner is also made with corrugations so that when heated
and being shrunk in position on the shaft, A, and also afterwards when the shaft
is working the corrugations allow for expansion or contraction of the two end
parts, D. E, of the liner thus preventing the possibility of the liner becoming
fractured and permitting water to get access to and corrode the shaft, A.
The shape and number of the corrugations in the middle part, C, may be
varied as may be found most convenient in practice.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, 1 declare that what
I claim is:-
A cover or liner for screw propeller shafts made in one piece and extending
the whole length of the stern tube the middle part between the two end parts
being of a corrugated or equivalent form substantially as and for the purposes
hereinbefore described.
1
1000