AN IMPROVEMENT IN THE BEARINGS AND BUSHES FOR THE SHAFTS OF SCREW AND SUBMERGED PROPELLERS
Year: 1854

page_text: LETTERS PATENT to John Penn, of Greenwich, in the County of Kent,
Engineer, for the Invention of "AN IMPROVEMENT IN THE BEARINGS AND
BUSHES FOR THE SHAFTS OF SCREW AND SUBMERGED PROPELLERS."
Sealed the 21st November 1854, and dated the 2nd October 1854.
PROVISIONAL SPECIFICATION left by the said John Penn at the Office
of the Commissioners of Patents, with his Petition, on the 2nd October
1854.
I, JOHN PENN, of Greenwich, in the County of Kent, Engineer, do hereby
declare the nature of the Invention for "AN IMPROVEMENT IN THE BEARINGS
AND BUSHES FOR THE SHAFTS OF SCREW AND SUBMERGED PROPELLERS" to be as
follows:-
This Invention consists of employing wood in the construction of the
bearings and bushes for the shafts of screw and submerged propellers.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Penn in the Great Seal Patent Office on the
2nd April 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
PENN, of Greenwich, in the County of Kent, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Second day of October, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Penn, Her special licence that I, the said John Penn, my executors,
administrators, and assigns, or such others as I, the said John Penn, my
executors, administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands, and
Isle of Man, an Invention for "AN IMPROVEMENT IN THE BEARINGS AND BUSHES
FOR THE SHAFTS OF SCREW AND SUBMERGED PROPELLERS," upon the condition
(amongst others) that I, the said John Penn, by an instrument in writing
under my hand and seal, should particularly describe and ascertain the nature
of the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said John Penn, do hereby declare the nature
of the said Invention, and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement
thereof (that is to say) :-
-
This Invention consists of employing wood in the construction of the
bearings and bushes for the shafts of screw and submerged propellers.
Having thus described the nature of my said Invention, I will proceed to
describe the manner of performing the same.
DESCRIPTION OF THE DRAWING.
Figure 1 shows a side view, partly in section, of the raising frame for a
screw propeller, together with part of the shaft and blades; Figures 2
and 3 show the two end views of the two bearings of the shaft of the pro-
peller, which are carried by the raising frame. A, A, is the raising frame,

page_text: which is of the ordinary construction; B is the shaft of a screw or sub-
merged propeller; C, C, are the blades of the screw or submerged propeller;
D and E are the two bearings of the shaft, which are carried by the raising
frame A. The inner surfaces of these bearings are grooved to receive fillets
of wood x, x, which project to some extent beyond the inner surfaces of the
metal bearings, so as to prevent the shaft coming in contact with the metal of.
the bearings, and these spaces admit of the water flowing freely between the.
shaft B and the inner surfaces of the metal bearing. The wood which I
prefer for these purposes is lignum vitæ, but other wood may be used in place
thereof, and the grain of the wood may be longitudinal of the fillets, or at right
angles to the bearing surfaces thereof. In the arrangement shewn in Figures
1, 2, and 3, the grooves are made dovetail, to receive corresponding dovetail
forms of wood; but the means of fixing the pieces of wood may be varied, and
it is not essential that the several pieces of wood employed in a bearing should
be in a straight line parallel to the axis, and from end to end of a bearing, as
shown, as they may be in lines inclined to the central axis; and the pieces of
wood may be at intervals only, and not in continuous lines, as shewn. The
object of the Invention is, that the parts of a propeller shaft which are within
bearings shall not come in contact with metal of the bearings, but against
pieces of wood fixed therein, in such manner as to admit of water flowing
freely between the pieces of wood and between the inner surfaces of the
metal bearings and the outer surfaces of the propeller shaft.
Figure 4 shows a longitudinal section, and Figure 5 a transverse section, of
a propeller shaft revolving in a fixed bearing. In this arrangement x, x, are
several fillets of wood fixed within the bearing F. The edges of the fillets of
wood are bevilled, so that where each neighboring pair of fillets come
together, they leave a groove between them for the free passage of water. The
interior of the bearing is lined with these fillets of wood, as is shown, and the
whole are wedged tightly by the fillet of metal v, fixed in the bearing by
screws or otherwise. It is preferred that the surfaces of the propeller shaft
which are within the bearings should be bushed or covered with brass, and
that the bearings should be lined or bushed with brass. It is not essential
that the wood bearings for the shaft of a screw or submerged propeller should
be fixed to the interior of the fixed metal bearings, as a like effect is obtained
if the pieces of wood (whether in the form of fillets or otherwise, or whether
with the grain longitudinally or at right angles with their bearing surfaces,)
be fixed to the shaft and revolve therewith, as is shown in respect to the part
B' of the shaft B at Figure 1, where the fillets of wood a, a, are shown as
being let into grooves in the coating or bushing of brass, fixed on the part of

page_text: the shaft B', which is within the bearing F, and the bearing is also lined or
bushed with brass, as shown at w. I have not thought it necessary to show
all the bearings of a propeller shaft, but I would state that they are to be
similarly made to those above described, and it is desirable that in all cases
the bearings should be immersed in or well supplied with water.
Having thus described the nature of my said Invention, and the manner of
performing the same, I would have it understood that what I claim is, the
employing of wood in the construction of the bearings and bushes for the
shafts of screw and submerged propellers, as herein described.
In witness whereof, I, the said John Penn, have hereunto set my hand
and seal, this Twenty-eighth day of March, in the year of our Lord
One thousand eight hundred and fifty-five.
Witness,
THOMAS COOMBER,
Lewisham.
JOHN PENN. (L.S.)