IMPROVEMENTS IN SCREW PROPELLERS
Year: 1879

page_text: LETTERS PATENT to Herbert John Haddan, of the Firm of Herbert and
Company, Solicitors of Patents, of 67, Strand, in the City of Westminster,
Civil Engineer, for the Invention of "IMPROVEMENTS IN SCREW PROPELLERS."
A communication from abroad by Eugene A. Heath, of New York City,
United States of America.
Sealed the 6th February 1880, and dated the 16th September 1879.
COMPLETE SPECIFICATION filed by the said Herbert John Haddan at the
Office of the Commissioners of Patents on the 16th September 1879.
HERBERT JOHN HADDAN, of the Firm of Herbert and Company, Solicitors of
Patents, of 67, Strand, in the City of Westminster, Civil Engineer. " IMPROVE-
MENTS IN SCREW PROPELLERS." [A communication from abroad by Eugene A.
Heath, of New York City, United States of America.]
"
This Invention relates to that class of devices for propelling vessels known as
screw propellers," which as commonly used consist of a series or set of four
blades of peculiar shape and form; these blades in their rapid revolutions and
action possessing two powers, techanically termed the "inclined plane," and the
"lever," which blades acting upon the body of the water in a similar manner as a
threaded screw in a nut give the propelling power. The present Invention consists
in the novel application to the well known and conventional forms of screw pro-
peller blades, of a series of channels or flutes, such channels being cut on acute
angles into and retiring from the face of the blades. They are preferably cut on
curved lines radiating from the hub, and they may be more or less in number,
and be convoluted or overlie each other. The location of these channels upon the
impinging face of the blades and their wedge shape are such as to give an increased
grip upon the body of water, thereby increasing the propelling power of the
various blades.
As an adjunct to such channels or flutes, a series of perforations or openings are
made through the blades, either in and from the base of said channels or between
several of them, this for the purpose of permitting some of the water to pass
through to the rear of the blades, which action will result in destroying any
vacuum or partial vacuum that may form behind the rapidly revolving blades,
thereby causing the blades to operate in a solid body of water instead of a mass of
1

page_text: foam, all of which improvements, together with the method of applying and
operating them, will hereinafter be fully described and pointed out in detail.
In the Drawings, which form an essential part of this Specification, Fig. 1 is a
front elevation of a screw propeller in which my Invention is fully embodied, and
Fig. 2 is a side elevation of the same, one of the blades being shown in section.
The same reference letters marked on the two Drawings will locate and desig-
nate corresponding parts.
A, B, C, and D represent the several blades of the propeller, which is mounted
upon the shaft E. These blades may be cast separately, and afterwards attached
to the hub, or the hub and blades may be cast as a unit, as mechanical skill may deem
best. a, b, c, d, designate a series of channels or flutes formed in the body of the
blades. They are retired from the face of the blades to the rear on acute angles,
giving them a wedge-shape, as plainly shown in blade B in Figure 2. They are
also, preferably, formed on the line of a circle, see Figure 1, each circle being drawn
from the same center, this for the purpose of securing a gradual hold and an easy
action upon the water, both in the action of griping and releasing it. e, e¹, and e²,
represent a series of elongated slots cut through the blades, and located in between
the various channels, or a portion of them, or opening from the channels or from
the base thereof, such openings being of the same size on both the front and rear
faces of the blades. In some cases a series of straight holes H may be drilled
through the blades, as shown in blades B and D, Figure 1. In some cases angle
iron may be successfully riveted upon the face of the blades, giving an increased
grip upon the water; in other cases corresponding channels may be formed
upon the rear face of the blades. The object aimed at in this Invention is
two-fold; firstly, to increase the grip of the blades upon the water; and secondly,
in connection therewith to effectually prevent the formation of the vacuum or
partial vacuum that now extends in the common form of propeller blades. Claims :-
1st. A screw propeller wheel, the several blades of which are provided on their
impinging face with a series of wedge chaped channels, which retire from the face
to the rear, and are formed on curved lines radiating from the centre or hub of the
wheel. 2nd. A screw propeller wheel, the impinging faces of the blades of which
are provided with a series of corrugations overlying recesses, flutes, or con-
volutions, such being formed either on curved or straight lines radiating from the
centre or hub of the wheel, all substantially as and for the purposes as described.
3rd. A screw propeller wheel, the several blades of which are provided with a
series of wedge shaped recesses radiating from the hub and retired at an acute
angle from and below the faces of the blades, such recesses being provided with
perforations or elongated holes opening from the bases thereof to the rear faces of
the blades, all substantially as and for the purposes as shown and set forth.
In witness whereof, I, the said Herbert John Haddan, have hereunto set my
hand and seal, this Sixteenth day of September, A.D. 1879.