Improvements in Apparatus connected with the Lubrication of Sorew Propeller Shafts.
Year: 1899

page_text: Date of Application, 8th Nov., 1898
Complete Specification Left, 7th Aug., 1900-Accepted, 22nd Sept., 1900
Improvements in Apparatus connected with the Lubrication of Sorew
Propeller Shafts.
We, SUMMERS HUNTER, Manager, North Eastern Marine Engineering Com-
pany Limited, Wallsend on Tyne, and GEORGE MILNE, of No. 17, East Percy
Street, North Shields, Engineer, do hereby declare the nature of this invention
to be as follows:-
Our invention applies to some of various descriptions of apparatus which are
used where oil is employed for the lubrication of what is technically called the
"tail end shaft" of a screw steamer.
The difficulty which is experienced in the use of oil for this purpose is that
unless some thoroughly efficient packing be used at the after end of the stern
tube much oil escapes into the sea and there is waste, or water enters the stern
tube and there is inefficiency, or both.
The inner end of the stern tube is usually provided with a stuffing box of
ordinary construction which is at all times easily accessible to the engineer
in charge, who can adjust it as the packing wears away; but the outer end being
ordinarily under water and in close proximity to the path of the screw is prac-
tically quite inaccessible while the engines are running, and almost so at all
times unless the ship be in dry dock.
For this reason it is of the last importance that any packing whatever which
may be used to make the after end of the stern tube approximately oil and water
tight should be such a packing as shall require no adjustment beyond what may
be made absolutely automatic in its action.
The object of our invention is to provide such a packing.
We firmly attach, water and oil tight, to the end of the stern tube a ring in
two halves accurately faced on the outer side with its face parallel to the path
of the screw; this we call the first ring, and against this we place a second
ring also in two halves, but firmly bolted together and preferably with a
diagonal joint, and faced on its front side with any good anti-friction metal,
so that when these rings are pressed together face to face the joint between
them may, without any packing, be practically oil and water tight. For con-
venience of description we use the words first, second, and third rings through-
out this specification to identify and more clearly explain the different parts of
our apparatus.
We bolt firmly, water and oil tight, a third ring or short tube, or cylinder
accurately bored but also in two halves, to the boss of the propeller so that
it overlaps to a desired extent the second ring; and we arrange that the second
ring and the third ring shall both revolve together; but their attachment for
this purpose is not so rigid an attachment as that this third ring shall be unable
to move a little upon the second ring, or the second ring within the third ring
in the direction of the length of the shaft. The object of this slight movement
being to compensate for the absence of absolute rigidity in the thrust block.

page_text: .
I will be seen that by this arrangement there are two places where, by reason
of moving joints, water or oil might pass into or out of the stern tube, that is
to say between the faces of the first and the second ring, where one revolves upon
the other, or, between what we have called the second and third rings, circum-
ferentially, where the second is able to make a slight telescopic movement
within the third.
In order to prevent leakage between the first and second rings we use springs
which may be spiral or of any other convenient shape which are placed in such
a state of compression between the second and third rings, as to compensate
automatically for any wear which may take place on the faces of the moving
joint between the first and second rings; and in order to prevent leakage
between the second and third rings we fit within the second ring (in a recess
or groove turned in it for the purpose) an arrangement resembling a piston
packing ring that is to say a metallic ring with springs to keep it up to the
cylindrical ring as is well understood. For greater security however, and in
order to avoid the use of what in a piston is called a junk ring, we prefer to
make the piston packing referred to in the form of two rings side by side, so
shaped on the inside of each as that a blunt wedge, pressed behind and between
these two rings from the inside, shall tend to separate the one from another
and to press their outside edges against the inside edges of the recess or groove
before referred to: that is to say the section of these rings when laid together
might be described as to some extent saddle shaped or V shaned inside and
pressure tending to open the saddle or V presses them apart and to the sides
of the recess or groove provided in the second ring. Under the packing ring
we place another ring the outer section of which is shaped like an inverted V
but with obtuse angularity corresponding with what we have called the saddle
or V shape of the packing rings inside. Behind these rings we place springs
of any convenient form spiral or otherwise pressing the wedged shaped ring
against the two packing rings, so as to press them in turn outwardly against
what we have called the third ring and also apart from each other and therefore
against the sides of the recess in which the packing rings are placed. These
packing rings it will he understood are cut in one or more places and may be
fitted with tongue pieces as is usually with piston packing rings.
We place around the whole of the mechanism which we have described, a
strong protective casing attached to the stern tube nut, so as to prevent injury
to the less substantial parts within, and to prevent ropes or other matters from
coming against them.
Improvements in Apparatus connected with the Lubrication of Screw
Propeller Shafts.
We, SUMMERS HUNTER, Manager, North Eastern Marine Engineering Com-
pany Limited, Wallsend on Tyne, and GEORGE MILNE, of No. 17, East Percy
Street, North Shields, 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:
11
Our invention applies to some of various descriptions of apparatus which are

page_text: used where oil is employed for the lubrication of what is technically called the
"tail end shaft" of a screw steamer.
The difficulty which is experienced in the use of oil for this purpose is that
unless some thoroughly efficient packing be used at the after end of the stern
tube much oil escapes into the sea and there is waste, or water enters the steru
tube and there is inefficiency; or both.
The inner end of the stern tube is usually provided with a stuffing box of
ordinary construction which is at all times easily accessible to the engineer
in charge, who can adjust it as the packing wears away but the outer end being
ordinarily under water and in close proximity to the path of the screw is prac-
tically quite inaccessible while the engines are running and almost so at all
times unless the ship be in dry dock.
For this reason it is of the last importance that any packing whatever which
may be used to make the after end of the stern tube approximately oil and water
tight should be such a packing as shall require no adjustment beyond what may
be made absolutely automatic in its action.
The object of our invention is to provide such a packing.
We firmly attach water and oil tight, to the end of the stern tube a ring in
two halves accurately faced on the outer side with its face parallel to the path
of the screw; this we call the first ring, and against this we place a second
ring also in two halves, but firmly bolted together and preferably with a
diagonal joint, and faced on its front side with any good anti-friction metal,
so that when these rings are pressed together face to face the joint between
them may, without any packing, be practically oil and water tight. For con-
venience of description we use the words first, second and third rings through-
out this specification to identify and more clearly explain the different parts of
our apparatus.
We bolt firmly, water and oil tight, a third ring or short tube or cylinder
accurately bored but also in two halves, to the boss of the propeller so that
it overlaps to a desired extent the second ring; and we arrange that the second
ring and the third ring shall both revolve together; but their attachment for
this purpose is not so rigid an attachment as that this third ring shall be unable
to move a little upon the second ring, or the second ring within the third ring
in the direction of the length of the shaft. The object of this slight movement
being to compensate for the absence of absolute rigidity in the thrust block
It will be seen that by this arrangement there are two places where by reason
of moving joints, water or oil might pass into or out of the stern tube, that is
to. say between the faces of the first and second rings, where one revolves upon
the other, or between what we have called the second and third rings, circum-
ferentially, where the second is able to make a slight telescopic movement
within the third.
In order to prevent leakage between the first and second rings we use springs
which may be spiral or of any other convenient shape which are placed in such
a state of compression between the second and third rings, as to compensate
automatically for any wear which may take place on the faces of the moving
joint between the first and second rings. We fit within the second ring (in a recess
or groove turned in it for the purpose) an arrangement resembling a piston
packing ring that is to say a metallic ring with springs to keep it up to the
cylindrical ring as is well understood. For greater security however, and in
order to avoid the use of what in a piston is called a junk ring, we prefer to
make the piston packing referred to in the form of two rings side by side, 80
shaped on the inside of each as that a blunt wedge, pressed behind and between
these two rings from the inside, shall tend to separate the one from the other
and to press their outside edges against the inside edges of the recess or groove
before referred to that is to say the section of these rings when laid together
might be described as to some extent saddle shaped or V shaped inside and

page_text: pressure tending to open the saddle or V presses them apart and to the sides
of the recess or groove provided in the second ring. Under the packing ring
we place another ring the outer section of which is shaped like an inverted V
but with obtuse angularity corresponding with what we have called the saddle
or shape of the packing rings inside. Behind these rings we place springs
of any convenient form spiral or otherwise pressing the wedged shaped ring
against the two packing rings, so as to press them in turn outwardly against
what we have called the third ring and also apart from each other and therefore
against the sides of the recess in which the packing rings are placed. These
packing rings it will be understood are cut in one or more places and may be
fitted with tongue pieces as is usual with piston packing rings,
We place around the whole of the mechanism which we have described, a
strong protective casing attached to the stern tube nut, so as to prevent injury
to the less substantial parts within, and to prevent ropes and other matters from
coming against them.
In the drawing hereto attached is shewn Fig. 1. A section of part of the pro-
peller shaft marked A. A section of the after end of the stern tube and the
stern tube nut both marked B. A section of the after part of the stern bush
marked C. This stern bush is fitted internally with white metal or wood
bearing surfaces but for clearness we omit lettering of this detail in the drawing
it being a well understood and common engineering arrangement.
To the after end of the stern bush C, is attached (water and oil tight) an
accurately faced ring D. This ring is made in 2 halves for convenience of
attachment.
The detail of the attachment of these two halves to each other we however
omit for the sake of clearness as being a quite well understood and common
engineering device which may be varied in many ways.
This ring D is what we have hitherto in this description called the first ring,
When the halves are fastened together it is practically a solid ring. Being
attached to the stern bush it does not revolve with the shaft.
What we have called the second ring is also in two halves for convenience
of attachment but for the reason before given we omit the detail of the attach-
ment of the two halves to each other. It is practically a solid. ring when in
actual use. The forepart or face of this ring is fitted with white metal accurately
faced so as to correspond exactly with the after face of the ring D. This second
ring is marked E the white metal face is not shaded with diagonal lines and is
marked e. The ring E is free to slide a limited distance along the propeller
shaft, there being adequate clearance diametrically to enable it to slide easily.
In the drawing of Fig. 1 we have omitted some of the details of ring E
because in so small a scale the details would be too minute, and the lettering
would increase the intricacy of the drawing. We however shew these omitted
details in Figs. 2 and 3.
At the after end of this ring E, there are spiral springs shewn in Fig. 3,
and marked F which are held in position by being, as to the greater part of
their length when in a state of compression, confined in drilled holes in the
after end of the ring E.
These springs bear at their after end against the propeller boss (marked P in
Fig. 3) which is accurately faced, and at their fore end they bear against the
bottoms of the bored holes in the ring E in which they are confined, so that when
in a state of compression the effort of expansion tends to push the propeller
back and the ring Ę forward on the shaft. The propeller being fixed however
the effort of expansion is applied wholly to keep the white metal face of the
ring E in close contact with the after face of the ring D so as to make and main-
tain the joint between D and E approximately oil and water tight.
The ring E revolves with the propeller driven either by pins in the propeller
boss or by feathers on the propeller shaft or by any other convenient means.

page_text: We omit for the sake of clearness the actual means of driving for reasons already
given and because any efficient means of driving will answer the desired purpose.
In the outer circumference of the ring E we turn a groove with straight sides
and flat bottom, this groove is shewn at G, Figs. 2 and 3. For better under-
standing of the details of the fittings of the groove G we shew in Figs. 2 and 3
an enlarged section (as compared with Fig. 1) of the groove and the various
parts which are fitted in it when in use. In Fig. 2, H is a spiral spring not
shewn in Fig. 3. A sufficient number of springs are placed in flat bottomed
holes drilled at the bottom of the groove before mentioned and on these springs
the part I is laid in such way as that it shall when in position exert a com-
pressing action on the springs. Over the part I we lay the two identical
parts J, J, the slope on the outer circumference of the part I corresponding to the
slope on the inner circumference of the parts J J. The rings I and J J are for
convenience made in two or more parts and may be fitted with tongue pieces
at the joints. It will thus be observed that when the springs are in compression
the effort of expansion tends to force the part I in an outward direction. But
the movement of the part I in an outward direction tends to force the parts J J
in two directions that is to say outwards by the direct movement of the part I
but also sideways in proportion to the acuteness of the angle of bearing of the
part I upon the parts J J. Thus if the outward movement be in any degree
prevented the sidewards movement or the effort of expansion of the springs
presses the sides of the ring J J against the sides of the groove G so as to make
joints approximately water tight and oil tight at each side of the groove as well
as between I and J J and between J J and the ring K. The drilled holes for
containing the spiral springs shewn in Figs. 2 and 3 are so arranged as not to
intersect each other.
K (Fig. 2 and 3) is a section of what we have called the third ring. It is
accurately bored and faced and securely bolted water and oil tight to the boss
of the propeller at the forward side and revolves with the propeller and with
the ring E.
.
There are thus in our arrangement two parts of the apparatus where oil
might escape from, or where water might enter into the stern tube, namely,
at the junction of the ring D, with the ring E (but this is more or less effec-
tually prevented by the constant pressure of E upon D) and at the junction of
the ring E with the ring K, (this is however more or less effectually prevented
by the arrangement of springs and packing in the groove made in E.
L. (Fig. 1) is a protecting cover for the whole mechanism of our invention
to prevent injury from contact with any floating object or fouling of ropes or
chains.
It has long been a desideratum to provide such a system of packing for pro-
peller shafts as that embraced in our invention and different descriptions of
apparatus have been devised for this purpose; before therefore describing what
we claim as our invention we wish to define specifically what we do not claim.
We do not claim for instance that which was claimed in the Specification of
Pitt No. 20688 the ring as such applied hetween the propeller and the stern
post in combination with a boss upon the stern post substantially in the
manner and for the purpose set forth.
We do not claim the invention described in the Specification of Robertson
5324 entered in the Patent Office Index in the terms following
"Stuffing box revolves with shaft held on stern tube by springs secured to
ring on shaft."
Nor do we claim the invention described in Specification of Cedervale 985487
with claims as follows, reference being made to drawings which we omit.
First the protective box with oil reservoir for screw bushings consisting of
an outer ring surrounding the screw shaft and fastened at the screw centre or
the bushing nut in which ring an inner ring retained against the bushing nut
or the screw centre by means of spiral springs can move in the longitudinal

page_text: direction of the shaft and which inner ring is compelled to follow the rotary
motion of the outer ring by means of trunnions engaged in the inner ring a
packing being placed between the above mentioned two rings, these rings
conjointly with the shaft and the end of the bushing forming an annular oil
reservoir, from which the oil cannot get out and to which the water cannot
get in, the protective box being moreover surrounded by a protective ring sub-
stantially as described.
Second. The arrangement of the screw bushing with the view of employing
the above mentioned protective box, in such a manner that the aft bearing
of the bushing is provided with two or more oil grooves and an air groove open-
ing in the oil reservoir mentioned in the first claiming clause, the bushing
being besides provided with pipes for letting in and out the oil and with a pipe
for letting out the air, by means of which pipes water can be made to pass
through the bushing when the oil has been let out, substantially as and for the
purpose specified.
Nor do we claim the invention described in the Specification of Irwin 1148697
dispensing with one of the packings necessary in our invention.
But having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what
we claim is:-
-
The combination and arrangement of parts substantially as described whereby
the necessary security against egress of oil out of or ingress of water into the
stern tube of a screw propeller ship is secured in a more permanently efficient
manner than heretofore and in especial we claim for this purpose packings
illustrated in Figs. 2 and 3.