Improvements in Stern Tubes and Propeller Shafts for Single and Twin Screw Steamers.
Year: 1894

page_text: Date of Application, 14th Dec., 1894
Complete Specification Left, 28th Aug., 1895-Accepted, 9th Nov., 1895
DEPUITICATION.
Improvements in Stern Tubes and Propeller Shafts for Single and
Twin Screw Steamers.
I, WILLIAM BRUCE THOMPSON residing at Ellangowan Dundee in the County
of Forfar Scotland Engineer do hereby declare the nature of this invention to
be as follows:-
:-
This invention relates to the improvement in construction of stern tubes and
propeller shafts. The object being to do away with the brass covering on the
propeller shafts.
To keep the bearing surfaces lubricated and to exclude the water and grit from
entering the tube and also the ship in the event of the tube or shaft breaking.
These objects are attained by forming in each end of the stern tube an ordinary
stuffing box fitted with a soft packing and also a metallic packing of such a
composition as to have no corrosive action on the shafting, and of sufficient length
to form a bearing for the shafting running on.
This bearing can be renewed & the wear taken up without disturbing the
propeller & shafting.
The tube is fitted with pipes to admit and draw off the lubricant, the admission
pipe is carried above deep load line, or it may be feed automatically from the
tunnel.
12th December 1894.
WILLIAM BRUCE THOMPSON.
COMPLETE SPECIFICATION.
Improvements in Stern Tubes and Propeller Shafts for Single and
Twin Screw Steamers.
1, WILLIAM BRUCE THOMPSON, residing at Ellangowan, Dundee, in the County
of Forfar, Scotland, 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 :-
This invention relates to improvements in the construction of stern tubes and
propeller shafts, the objects being to do away with the brass covering on the
propeller shaft, to keep the bearing surfaces lubricated and to exclude the water
and grit from entering the tube and also the ship in the event of the tube or shaft
breaking.
And in order that my said invention and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory sheet of drawings in which the same reference numerals
are used to indicate corresponding parts in all the figures where shown.
Figure 1. is a longitudinal section through the axis of the propeller shaft showing
a portion of the stern post and stern tube.
Figure 2. is a face view of the gauge which is used in the determination of the
position of the shaft.

page_text: The aforesaid objects are attained by forming in each end of the stern tube 10,
stuffing boxes 11. and 12, such boxes being filled with soft packing 13, and also
metallic packing 14, of such a composition as to have no corrosive action on the
shafting and of sufficient length to form a bearing or hearings for the shafting
running on. The metallic packing rings are preferably turned or cast to the
section shewn, that is to say each ring. of triangular cross-section and preferably
divided circumferentially into three parts, the object of such construction being to
cause alternate rings to press against. the shaft and the. stern tube, the pressure
depending on the force exerted upon the soft packing by the glands 20. and 21.
The bearings can be readily renewed, and, by the aforesaid means, namely by the
adjustment of these glands, the wear can be taken up without disturbing the
propeller and shafting. The tube 10. is fitted with pipes 15. and 16. to admit and
draw off the lubricant from the receptacle 17.
The admission pipe 15, is carried above deep load line so that the."head"" of the
lubricant may exceed the "head" of external water, the lubricant in this manner
excluding such water. Should the outer gland leak at the stern post 18, or the
shaft or stern tube be broken, the inner gland and the after peak bulkhead 19, will
effectually exclude water from further entering the vessel.
Sometimes the lubricant may be fed automatically from the tunnel. The stern
tube may be of cast iron or steel and is fastened to the after peak bulkhead by the
bolts 22, its other extremity fitting into the stern tube and held there by the nut 23.
24. is a hand hole usually closed by the cover 25, but removed when the gauge 26.
is used. Such gauge is made, when the shaft is newly fitted into position, to give
the exact distance between the face of the hand hole and the top of the shaft, it
being attached to the cover 25, while the shaft is in use. If the bearings wear aud'
the shaft goes out of alignment the amount of such displacement may be ascertained
by measuring the space between the top of the shaft and the face 27. of the gauge
at' the time its shoulders are bearing on the face of the hand hole and the gauge
is normal to same. The glands 20. and 21. are provided with bushes of non-
corrosive metal 28. and 29.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
(1) In combination with a propeller shaft, the stern tube 10, stuffing boxes 11.
and 12, soft packing 13, metallic packing 14, glands 20. and 21, pipes 15. and 16,
receptacle 17, stern post 18, bulkhead 19, bolts 22, nut 23, hand hole 24, cover 25,
gauge 26, and bushes 28. and 29, substantially as described and for the purposes
set forth.
(2) The stern tube 10, substantially as described.
(3) The combination of the soft packing 13. with metallic packing 14,
substantially as described and for the purposes set forth.
(4) The modes of supplying lubricating material to the shaft, as described.
Dated this 22nd day of August 1895.
GEO. C. DOUGLAS & Co.,
41 Reform Street, Dundee, Agents for Applicant.