Improvements in Lubricating Arrangements for Tail End Shafts of Marine Screw Propelling Engines.
Year: 1897

page_text: Date of Application, 8th May, 1897
Complete Specification Left, 8th Feb., 1898-Accepted, 19th Mar., 1898
Improvements in Lubricating Arrangements for Tail End Shafts of
Marine Screw Propelling Engines.
I, JOSHUA HYDE IRWIN, General Manager and Director of the North Eastern
Marine Engineering Company Limited, South Dock, Sunderland, do hereby
declare the nature of this invention to be as follows:-
My invention applies to engines in which the tail end shaft is lubricated
throughout most of its length by direct supply of oil, or other lubricant, and con-
sists of arrangements whereby I more efficiently than heretofore, maintain the
security against leakage at the junction externally of the moving shaft with the
fixed stern tube. At the inner end of the shaft I may use an ordinary stuffing
box; but at the outer end an ordinary stuffing box being under water, and very
inaccessible would be very inconvenient and uncertain; and spring stuffing boxes
I believe are not sufficiently reliable.
I therefore employ for the outer end of the shaft a plate or disc fixed to and
revolving with the shaft which plate bears upon the faced end of the stern tube,
both faces being turned with fitting concentric rings and grooves, or any other
device for extra security if desired. (By reversal of the parts I might make this
plate or disc bear against the faced boss of the propeller, or against a separate face
piece fixed to the shaft or the propeller, the alternative however being in no way
of the essence of our invention.) I describe my arrangement therefore as first
referred to, namely, a faced plate revolving with the shaft and bearing against
a similarly faced plate not revolving with the shaft but fixed oil and water tight
to the end of the stern tube or its liner.
If it were possible to secure absolute rigidity in the position, longitudinally,
of the tail end shaft, the plate referred to as revolving with it, it might be fixe],
oil and water tight, to the shaft; but such absolute rigidity is impossible. And
if in the absence of rigidity I fix the plate in this way it would put at times the
full thrust of the propeller (through this plate) upon the stern tube or its liner:
and at other times as when slowing, stopping or especially reversing the engines
the drag of the propeller would more or less lift the plate from its bearing, and
allow ingress of water and egress of oil. It thus becomes necessary to give the
plate a sliding motion on the shaft, or rather the shaft a sliding motion through
the plate, and the relative diameters of the shaft and of the opening of the plate
must be such as to give considerable freedom of movement and therefore such as
to afford passage for leakage unless means be taken to prevent it.
The means hitherto employed have been stuffing boxes of one kind or another,
the objection to which I have already referred to. Now I by my invention am
enabled to dispense with any stuffing box and yet to secure absolute non-leakage
with any reasonable degree of freedom of movement.
I fix permanently to the boss of the propeller or to a ring fixed oil and water
tight upon the haft in front of the propeller a membranous material, metallic or
otherwise, in the form of a closed case covering both the revolving and the

page_text: stationary parts of the sliding joint referred to; or covering it oil and water tight
when attached to the revolving dise described. This membrane is elastic in the
longitudinal direction of the shaft to the desired degree. It may be made in many
varieties of shapes, and in many varieties of materials.
This membrane being fixed as described at the after end, is also fixed oil and
water tight at the forward end to the revolving disc; and thus a space is enclosed
which may be continuously filled with oil without leakage.
I may keep the discs pressed together by springs quite independently of the
membrane. I prefer also to ensure the movement of the revolving disc on the
fixed disc quite independently of the membrane. I prefer also to make the mem-
brane of light material and to protect it from accidental injury by strong outer
caso.
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Improvements in Lubricating Arrangements for Tail End Shafts of
Marine Screw Propelling Engines.
I, JOSHUA HYDE IRWIN, General Manager and Director of the North Eastern
Marine Engineering Company Limited, South Dock, Sunderland, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
My invention applies to engines in which the tail end shaft is lubricated
throughout most of its length by direct supply of oil, or other lubricant, and con-
sists of arrangements whereby I more efficiently than heretofore maintain the
security against leakage at the junction externally of the moving shaft with the
fixed stern tube. At the inner end of the shaft I may use an ordinary stuffing
box but at the outer end an ordinary stuffing box being under water, and very
inaccessible, would be very inconvenient and uncertain; and spring stuffing boxes
I believe are not sufficiently reliable.
I therefore employ for the outer end of the shaft a plate or disc fixed to and
revolving with the shaft which plate bears upon the faced end of the stern tube,
hoth faces being turned with fitting concentric rings and grooves, or any other
device for extra security if desired. (By reversal of the parts I might make this
plate or disc bear against the faced boss of the propeller, or against a separate face
piece fixed to the shaft or the propeller, the alternative however being in no way
of the essence of my invention.) I describe my arrangement therefore as first
referred to, namely, a faced plate revolving with the shaft, and bearing against
a similarly faced plate not revolving with the shaft, but, fixed oil and water tight
to the end of the stern tube or its liner.
If it were possible to secure absolute rigidity in the position, longitudinally,
of the tail end shaft, the plate referred to as revolving with it might be fixed,
oil and water tight, to the shaft; but such absolute rigidity is impossible. And
if in the absence of rigidity I fix the plate in this way it would put at times the
full thrust of the propeller (through this plate) upon the stern tube or its liner;
and at other times as when slowing, stopping or especially reversing the engines
the drag of the propeller would more or less lift the plate from its hearing, and
allow ingress of water and egress of oil.. It thus becomes necessary to give the
plate a sliding motion on the shaft, or rather the shaft a sliding motion through

page_text: the plate, and the relative diameters of the shaft and of the opening of the plato
must be such as to give considerable freedom of movement and therefore such as
to afford passage for leakage unless means be taken to prevent it..
The means hitherto employed have been stuffing boxes of one kind or another,
the objection to which I have already referred to. Now I by my invention am
enabled to dispense with any stuffing box and yet to secure absolute non-leakage
with any reasonable degree of freedom of movement.
I fix permanently to the boss of the propeller or to a ring fixed oil and water
tight upon the shaft in front of the propeller a membranous material, metallic or
otherwise, in the form of a closed case, covering both the revolving and the
stationary parts of the sliding joint referred to; or covering it oil and water tight
when attached to the revloving disc described. This membrane is elastic in the
longitudinal direction of the shaft to the desired degree. It may be made in many
varieties of shapes, and in many varieties of materials.
This membrane being fixed as described at the after end, is also fixed oil and
water tight at the forward end to the revolving disc and thus a space is enclosed
which may be continuously filled with oil without leakage.
I may keep the discs pressed together by springs quite independently of the
membrane. I prefer also to ensure the movement of the revolving disc on the
fixed disc quite independently of the membrane. I prefer also to make the mem-
brane of light material, and to protect it from accidental injury by strong outer
case.
My invention may be operated in various ways with various descriptions of
material and in various shapes without in any way touching the principle involved.
The drawing hereto attached must therefore be taken as an illustration mercly of
the principle of my patent and not as forming the subject of it.
In the drawing hereto attached I have omitted for the sake of clearness all usual
well known details of construction and even proportions of parts.
A is part of the screw shaft, and B part of section of the boss of the pro-
peller. C is a section of part of the after end of the stern tube faced truly at right
angles to the shaft centre line. The problem solved by my invention is the making
of an approximately water and oil tight joint between B and C while allowing
these parts a certain amount of play, in approach to, and recession from, each
other. D is a section of a plate, ring or disc which is free to slide longitudinally on
the screw shaft but so keyed as that it must revolve with it. The surfaces of C
and D where they touch are accurately turned and may be further provided with
interlocking grooves and projections to any desired degree so as to give additional
accuracy of fit and to make and maintain a perfect joint, and they may partake of
the shape known as the anti-friction curve so as as much as possible to compensate
for wear. E are springs in compression between B and D) the effect of which
is to strongly press the face of D against the face of C so as to prevent the escape
of oil or the ingress of water between them excepting in so far as may be required
for lubrication. What is then further required is an oil and watertight covering
between D and B. This may be formed even of india rubber, waterproof cloth or
any other convenient elastic material, but, as a matter of choice, I prefer a metallic
covering of such shape as that it shall of itself possess sufficient elasticity to allow
the small give and take which is required by the approach and recession of the
parts B and D in reference to each other. And although this may be done in
various ways I prefer, as a matter of choice, a corrugated tube, the corrugations
being circular round the tube as shewn in the drawing at F.
Over the whole as a protection I fit a tube G to the stern post to cover against
injury the light corrugated tube or other elastic membrane last described.
It will thus be seen that oil supplied within the inner stuffing box of the stern
tube has no way of escape but between the joint of D and C and that this joint is
made independent or almost independent of the thrust or drag of the propeller
which would otherwise tend to press too severely or to open the joint.

page_text: Having now particularly, described and ascertained the nature of my said
invention, and in what manner the same is to be performed I declare that what
I claim is:-
The combination of apparatus whereby an approximately water and oil tight joint
may be made and maintained without a stuffing box at the outer end of a screw 5
propeller shaft substantially as described.
Datca tus rum day of reoruary 1000.
J. JAMESON,
Newcastle-on-Tyne, Agent for Applicant.