Improvements in Propellers.
Year: 1892

page_text: Date of Application, 1st Mar., 1892-Accepted, 7th May, 1892
CUMFLUID SPECIFICATION.
Improvements in Propellers.
We, WILLIAM AUGUSTUS BALDWIN, of 9, West 14th Street and ROSWELL
DOUGLAS SAWYER, of 58, West 57th Street both in New York, in the County of
New York, and State of New York, United States of America, Gentlemen, 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:
This invention relates to a propeller wheel to be used on boats using steam or
other motive power and may be advantageously used in propelling canal boats.
The object of the invention is to utilize the full force of the resistance which the
water will naturally afford and get an increased motion without increasing the
motive power by having each blade arranged in a different path from its preceding
one and successively reach out and cut still water or water which has not to any
measure been agitated by the blade arranged in advance of it.
With this and other objects in view this wheel or propeller has been constructed
in which a line drawn around the shaft at the base of the blades would describe a
spiral and another line drawn over the tips of the blades would produce a similar
figure of greatly increased diameter from the rear to the forward end of the shaft
on which such blades are mounted.
The invention will be fully understood from the following description and claims
when taken in connection with the annexed drawing in which :
The figure is a side elevation of a part of the hull of a vessel showing the
improvements applied.
While we have shown the interrupted screw or propeller applied to the rear or
stern of the keel, yet in some cases we may arrange one of such propellers en each
side as well, but we do not wish to be understood as confining ourselves to any
number of propellers nor to any particular point of location but may use as many of
them as the dictation of the mechanic or builder may suggest.
Referring by letter to said drawings:
A indicates the hull of a vessel which may be of any ordinary or approved con-
struction, and B indicates the usual stern-post.
The
C indicates the shaft of the propeller. This shaft has its forward end bearing in
the stern of the vessel and its opposite end bearing in the stern-post as shown, and
may be connected with the drive-shaft of the boat in any suitable manner.
shaft C may be solid and tapers from end to end; the smaller end being directed
forwardly.
In some cases it may be desirable to have a hollow sleeve or hub over the shaft
and in such cases the bore of the hub or sleeve would be of a tapering or conical
form so as to firmly bear on the shaft throughout its length and set screws, bolts
and nuts or other suitable devices may be employed for removably or permanently
fixing the sleeve in position on the shaft.
D indicates the paddles or blades which may be of any desired length and width
and are preferably provided with flat sides and are given a slight twist as
shown.
We have represented these blades as containing four to a complete whorl,
although a greater or less number may be employed.
The blades of the first whorl b, are of an equal length and width and arranged at
equal distances apart in a spiral or helical manner, while the blades of the next
succeeding whorl c, are of a greater length and arranged respectively in a line with
he interspaces formed between the advanced or preceding set.
The next succeeding set of blades are arranged on the shaft in a similar staggering
D

page_text: position and are of an increased length so as to reach out into and cut the still
water or water which has not been agitated by the blades ahead of them and so on
increasing in length until the desired number of whorls or spirals have been
made.
In practice we should make from two to four whorls although more or less might
be made as desired.
With a boat equipped with a propeller of this construction, there is little or no
lost motion. The movement of the boat will be steady and forward and a greater
speed will be had with a less amount of motive power, inasmuch as each and every
blade will not enter the water which has been violently agitated by its predecessor
but will successively reach out and move in a path of still or undisturbed water,
thereby meeting with resistance but on one side of the blades and avoiding any
tendency to move but in one rotative direction.
While we have described the blades as increasing in length from the forward to
the rear end of the shaft, yet it is obvious that when a shaft has a tapering
cylindrical outer surface the blades may be of equal length and they would
necessarily increase the diameter of the whorls from front to rear of the shaft.
In some cases it is not necessary that care should be taken to have all of the
blades of the same length as they may be made of unequal lengths and serve
effectively.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
i
1. A propeller for vessels comprising a shaft of tapering cylindrical form and an
interrupted screw formed of blades having their outer ends or tips approximately
parallel with the outer surface of the shaft and also forming in outline a tapering
cylinder substantially as specified.
2. A propeller for vessels comprising a shaft having an external cylindrical
surface tapering from its rear to its forward end and a series of blades or paddles
arranged spirally around the shaft the blades of the spirals describing a larger
circular area from front to rear of the shaft and arranged so that the blades of one
whorl will lie in a line with the interspaces of the preceding whorl, substantially as
specified.
3. The combination with the shaft having its outer surface of a tapering
cylindrical form, of the blades arranged spirally around the shaft so that their outer
ends will also describe a spiral tapering in a manner corresponding with that of the
shaft, substantially as specified.
Dated this 1st day of March 1945
W. P. THOMPSON & BOULT,
Agents for the Applicants.