Improvements in the Manufacture of Screw Propellers.
Year: 1895

page_text: Date of Application, 2nd Feb., 1895
Complete Specification Left, 4th Nov., 1895-Accepted, 7th Dec., 1895
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Screw Propellers.
We, THOMAS SMITH AND SONS OF SALTLEY, LIMITED, of 21, Whittall Street,
in the City of Birmingham, and of Saltley Mill Birmingham, Cycle Manufacturers,
and Metal Stampers, and THOMAS SMITH, of 21, Whittall Street, aforesaid, and
of Saltley Mill, aforesaid, Manager of the Stamping Department of the said
Company, do hereby declare the nature of this invention to be as follows:-
This invention consists of the hereindescribed improvements in the manufacture
of screw propellers for torpedoes and for small ships and boats. Heretofore it
has been customary to make the said propellers of cast metal but by this invention
we are enabled to forge the said propellers by a combination of simple processes
which we will now describe.
We will describe this invention in connection with a screw propeller which is
made with two blades although it is to be understood that this invention can be
similarly applied to propellers which are made with three or more blades.
According to one method of carrying out this invention we take a lump of
heated iron steel or other suitable ductile metal or alloy by preference of a circular
form and of sufficient size and by means of a pair of top and bottom stamping
dies we shape this heated lump of metal so as to form the boss of the screw
propeller with a projection on each side which projections under a steam hammer
or otherwise are drawn out to the proper length and thickness to form the blades.
By means of a pair of top and bottom stamping dies having the peculiar curved
form of one of the blades and also shaped so as to receive the boss we now stamp
the forging between these dies so as to impart to one of the blades the proper
peculiar curved shape and pitch; the forging
then half turned round and the
other blade is similarly operated upon by these last named dies thus completing
the screw propeller with a solid boss ready to be bored.
Instead of stamping the screw propeller with a solid boss as stated above we
may stamp the propeller with the necessary central hole in the boss for fixing the
same on the shaft. In this case the heated lump of metal above referred to with
the side projections formed on it is held between a pair of side dies whilst a punch
descends and by one or more blows forms the central hole in the boss. The blades
of the propeller are then finished to the proper curve and pitch by being stamped
between the dies as stated above.
Dated thin 91.4 1. of Tonus 1905
CHARLES BOSWORTH KETLEY,
Agent for the Applicants.
Improvements in the manu
We, THOMAS SMITH AND SONS OF SALTLEY, LIMITED, of Saltley Mill,
Birmingham, Cycle Manufacturers, and Metal Stampers, and THOMAS SMITH, of
O Saltley Mill, aforesaid, Manager of the Stamping Department of the said Company,
do hereby declare the nature of this invention and in what manner the same
2:017

page_text: is to be performed, to be particularly described and ascertained in and by the
following statement:--
This invention consists of the hereindescribed improvements in the manufacture
of screw propellers for torpedoes and for small ships and boats. Heretofore it has
been customary to make the said propellers of cast metal but by this invention we
are enabled to forge the said propellers by a combination of simple processes which
we will now describe.
We will describe this invention in connection with a screw propeller which is
made with two blades although it is to be understood that this invention can be
similarly applied to propellers which are made with three or more blades.
On the accompanying drawings
Fig. 1 is an end elevation and Fig. 2 is a side elevation of a screw propeller
made in accordance with this invention; Fig. 3 is a cross section of one of the
blades of the same;
Figs. 4, 5, 6 and 7 illustrate the progressive stages in the formation of the screw
propeller shewn by Fig. 1 from a lump of wrought iron or steel;
Fig. 8 represents in side elevation a pair of top and bottom stamping dies which
we employ in the first process of making the screw propeller, that is, in the
formation of the stamping shewn by Fig. 5;
Fig. 9 is a plan of the bottom die ;
Fig. 10 represents a pair of top and bottom stamping dies which we use in the
next operation, that is, in twisting the partly formed blades of the screw propeller
so that they will have the form represented by Fig. 6;
Fig. 11 is a side elevation of the top die and Fig. 12 is a plan of the bottom die;
Fig. 13 represents in side elevation the top and bottom stamping dies which we
employ in the next process, that is, for drawing down and rounding the blades of
the screw propeller;
Fig. 14 is a plan and side elevation of the bottom die ;
Fig. 15 represents in side elevation and Fig. 16 in end elevation the pair of top
and bottom stamping dies which we employ for finally finishing and imparting the
necessary helical form to the blades of the screw propeller;
Fig. 17 is a plan of the top die ;
Fig. 18 is a plan of the bottom die and
Fig. 19 shews the bottom die with a screw propeller in the position which it
occupies when it is being operated upon.
The same letters of reference indicate the same or corresponding parts in all the
figures of the drawings.
In carrying out this invention we take a lump of iron steel or other suitable
ductile metal or alloy of a circular or other form of sufficient size to form the
required screw propeller, and. by a steam hammer or other means we draw down
the lump A so as to form the two side projections B' B² somewhat as shewn by
Fig. 4.
This is then placed in the depression c¹ c³ of the bottom die C (Figs. 8
and 9) and is stamped by the top die D which has a pommel d¹ (corresponding
in shape and size with the central hole a' of the screw propeller before the same
is bored) thus forming the central hole a¹ in the stamping and forming the boss A
to the proper shape and also partly shaping the side projections B¹ B³ so that the
stamping will then have the shape indicated by Fig. 5. It will be understood
that the central part 2 of the depression in the die C is circular corresponding
with the outside of the boss A of the required screw propeller and the side
grooves el in the die C are narrow and slightly taper corresponding with the side
projections B B² of Fig. 5.
The next process is to twist the projections B' B² one in one direction and one
in the other direction so as to give the necessary inclination corresponding with the
inclination of the blades of the finished propeller. This is effected by placing
the stamping Fig. 5 on a taper mandrel corresponding with the hole a¹ and then
placing the stamping and the mandrel on the bottom die E (Figs. 10, 11 and 12)
so that the side projections B1 B2 lie in the cross grooves e¹e of the die E one of

page_text: g
these cross grooves e' being inclined in one direction and the other cross groove
being inclined in the opposite direction as shewn in Fig. 10. The central
depression e³ in the die E corresponds with the boss part A. The. top die F is
made a counterpart of the bottom die E so that when the stamping shewn
by Fig. 5 is heated and stamped by these dies E, F, the form of the dies will twist
the side projections B1 B2 one in one direction and one in the other direction and
thus impart to them the necessary inclination corresponding with the inclination of
the blades of the finished propeller. The stamping will then have the form
about as represented by Fig. 6. The next process is to draw out the side
projections B B to the necessary length width and thickness of the blades of the
finished propeller and also to impart to the blades the proper shape in cross section
as shewn by Fig. 3 which is flat on one side and rounded on the other side. This
we perform by the dies represented by Figs. 13 and 14 the bottom die G of which
is made with the sinking 9 slightly curved at the bottom and otherwise corre-
sponding with the shape of the finished blade when the same is straight as shewn
in Fig. 7. The top die H is flat underneath so that when one of the projections B
or B is operated upon by these dies it will be drawn out to the proper length
shape and thickness corresponding with the finished blade. These dies are
arranged to operate on only one blade at once so that when one of the blades has
been drawn out the stamping is turned round and the other blade is similarly
operated upon. The final operation of imparting to the blades B1 B2 their proper
peculiar curved form corresponding with the shape and pitch of the propeller is
performed by the top and bottom dies and J represented in Figs. 15, 16, 17, 18
and 19. It will be seen that these dies I J have each a part marked respec-
tively corresponding with the peculiar curved form of one of the blades B¹ B¹
and also shaped at to receive the boss part A of the propeller when the same
is in a slightly inclined position as shewn in Fig. 16. The propeller is placed on
the bottom die as represented in Fig. 19 which shews the propeller after both of
the blades have been operated upon, the blade B2 being in the position which it
occupies on the bottom die J immediately after the top die I has been raised from
it. When operating on the propeller we place a short mandrel in the hole a' just
of the proper shape and size to fill the hole so as to prevent the hole being closed
by the stamping operation. These dies I J thus impart to the blades one at a time
the proper peculiar curved shape and pitch. After one of the blades has been thus
operated upon the forging is turned round and the other blade is similarly operated
upon thus completing the screw propeller as shewn in Figs. 1 and 2 with the
central hole a¹ in the boss A ready to be bored.
Instead of forging the screw propeller with the central hole a¹ or eye in the
boss A as stated above it will be evident that the boss may if desired be forged
solid and in this case there will be no pommel d' on the top die D for the first
operation.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. The method of manufacturing screw propellers by stamping, said method
consisting in first forming a stamping such as represented by Fig. 5 consisting of a
boss A having a central hole and two side projections B₁ B³, then operating on
this stamping by dies such as represented by Figs. 10 and 11 which twist the two
side projections, then drawing out the said side projections to the shape in cross
section length and thickness of the propeller blades by stamping dies such as
represented by Figs. 13 and 14 and finally imparting the necessary curved shape
and pitch to the propeller blades by stamping the propeller in dies such as
represented by Figs. 15, 16, 17, 18 and 19 thus fiuishing the propeller with the
central hole ready to be bored, all substantially as hereinbefore described and
illustrated by the accompanying drawings.
2. The method of manufacturing screw propellers by stamping, stil method

page_text: consisting in first forming a stamping such as represented by Fig. 5 (but without
the central hole) consisting of a boss A and two side projections B' B³, then
operating on this stamping by dies such as represented by Figs. 10 and 11 which
twist the two side projections, then drawing out the said side projections to the
shape in cross section length and thickness of the propeller blades by stamping dies
such as represented by Figs. 13 and 14 and finally imparting the necessary curved
shape and pitch to the propeller blades by stamping the propeller in dies such as
represented by Figs. 15, 16, 17, 18 and 19 thus finishing the propeller but without
the central hole, all substantially as hereinbefore described and illustrated by the
accompanying drawings.
Dated this 2nd day of November 1895.
CHARLES BOSWORTH KETLEY,
Agent for the Applicants.