Improvements in Screw Propellers.
Year: 1885

page_text: I, BENJAMIN DICKINSON, of The Elms, Bourne End, in the County of Bucks,
East India Merchant, do hereby declare the nature of this invention to be as
follows:-
In the specification of my application for Letters Patent N° 9540. A.D. 1885 is
described an arrangement of screw propeller wherein the blades are arranged in
sets or series in such a manner that the blades of each set or series shall operate
independently, successively and continuously so that no two blades of one set can
act upon the same water.
Now, according to my present invention, in lieu of using two or more sets or
series of blades, I construct a propeller with one set of blades arranged upon the
boss or shaft in a spiral direction the pitch or inclination of the spiral being of the
opposite hand or denomination to that of the individual blades composing the set
and the arrangement being such that the rearmost blade travels in advance of the
succeeding or next blade and so on according to the number of blades, each blade
travelling in advance of the blade arranged next to and forward of it upon the boss
or shaft.
Improvements in Screw Propellers.
I, BENJAMIN DICKINSON, of The Elms, Bourne End, in the County of Bucks,
East India Merchant, 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 :-
In the specification of my application for Letters Patent N° 9540 A.D. 1885 is
described an arrangement of screw propeller wherein the blades are arranged in

page_text: sets or series in such a manner that the blades of each set or series shall operate
independently successively and continuously so that, no two blades of one set can
act upon the same water.
Now according to my present invention in lieu of using two or more sets or
series of blades, I construct a propeller with one set of blades arranged upon the
boss or shaft in a spiral direction the pitch or inclination of the spiral being of the
opposite hand or denomination to that of the individual blades composing the set
and the arrangement being such that the rearmost blade travels in advance of the
succeeding or next blade and so on according to the number of blades, each blade
travelling in advance of the blade arranged next to and forward of it upon the boss
or shaft.
Referring to the accompanying sheet of drawings Fig. 1 is an elevation shewing
that which, considered in relation to the shaft, is the forward end of a propeller
according to this invention, and Fig. 2 is a view at right angles to Fig. 1 shewing
the propeller as seen when looking in the direction of the arrow ①-
A, B, C, D, E, F are the propeller blades arranged in one set or series on the boss
or shaft G in a spiral direction, the pitch or inclination of the spiral being of the
opposite hand or denomination to that of the individual blades composing the set.
A is the rearmost blade of the set or series, that is to say it is nearest to the
rearmost extremity of the propeller shaft; B. occupies a more forward position
whilst F occupies the most forward position of the set or series.
For forward motion of the vessel the propeller rotates in the direction of the
arrow ② → the leading blade (considered with reference to the circle of rotation)
being the rearmost blade A which travels in advance of the succeeding or next
blade B which in its turn travels in advance of the next forward blade C and so on
relatively the arrangement being such that no two blades of the set or series
shall operate upon the same water, and that the water acted upon may readily
escape.
Although I have shewn six blades I do not confine myself to that number or to
the precise form of blade shewn. As will be evident two or more such propellers
may in some cases be arranged one behind another on a common shaft.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is
The improved screw propeller substantially as hereinabove described with
reference to and shown in the drawing annexed."