Improvements in the Construction of Screw Propellers.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in the Construction of Screw Propellers.
We, HARRY FOSTER, Storekeeper, and AARON BERESFORD, Tutor, both of No. 6,
Market Street, Eckington, in the County of York, do hereby declare the nature of
our invention to be as follows:-
Our invention relates to improvements in the construction of propellers for ships,
with the object of obtaining increased power of propulsion, without increase of
driving power.
Our invention consists in the combination with the arms or vanes of a propeller, ou
an encircling rim attached to and revolving with them.
We prefer to make the said rim slightly conical in configuration, the smaller end.
being the inlet, but we do not bind ourselves to this shape, nor to the number or
form of the vanes.
This construction avoids the churning of the water, and produces a direct thrusting
action..
ROBT. F. DRURY, C.P.A.,
Agent for Applicants,
Bank Buildings, George Street, Sheffield.
Improvements in the Construction of Screw Propellers.
We, HARRY FOSTER, Storekeeper, and AARON BERESFORD, Tutor, both of No. 6,
Market Street, Eckington, in the County of York, do hereby declare the nature of
this invention and in what manner the same has to be performed, to be particularly
described and ascertained in and by the following statement :-
Our invention relates to improvements in the construction of propellers for ships,
the object being to obtain increased power of propulsion without requiring an increase
of driving power.
Our invention consists in the combination with the blades or arms of a propeller, of
an encircling rim attached to the outer edges of the blades and revolving with them.
The method of carrying the invention into practice is shown in the annexed
drawings in which
Fig. 1, is a front elevation of a propeller constructed according to our invention.
Fig. 2, side elevation of same, part in section.
Fig. 3, shows a propeller with corrugated rim, the face or edge only being shown.
Fig. 4, shows the preferred angles of blades.
The blades B, of the propeller may be of any desired number and configuration.
Price R71

page_text: The rim R, encircles the blades B, and is attached to them either by casting them
together, in the case of small propellers, or by affixing them by any other mechanical
means.
The blades are preferably placed tangentially or in advance of the radial line as
shown, and we prefer as giving the best result in practice to curve them so that the
angle of the blade at the entrance side shall be 45 degrees, and 60 degrees at the
outlet or delivering side. We also prefer to narrow the width of the blades as they
approach the hub H.
In some cases we make the rim in sections, each section carried by a blade, and
in others we make the rim conical that is of smaller diameter on one (ie. the inlet)
side than at the other, in which case we also cone the hub so as to retain the passage
of uniform area, or thereabouts.
As a modification of our invention we may corrugate the rim as shown in Fig. 3,
such corrugations running across the rim at the same angle as the blades, as before
described.
The corrugations may be of any number and configuration, as experience may
decide to be best adapted for the work required of them, which is to act as an auxiliary
to the blades.
The combination of a rim with the blades and constructing the blades as herein-
before described, not only produces a direct thrusting action, but avoids the
churning of the water and consequent waste of power so prevalent in propellers of the
usual type.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what we
claim is :-
1-The combination with the blades of a ships propeller, of a rim either plain or
corrugated and secured to the outer edges of such blades so as to revolve therewith,
substantially as herein before described and shown.
2-The combination with the outer edges of the blades of a ships propeller, of
sections of a rim, as hereinbefore described.
Dated the 25th day of October 1897.
ROBT. F. DRURY,
Agent for Applicants,
Bank Buildings, George Street, Sheffield.