Improvements in Screw Propellers for Steam Ships.
Year: 1891

page_text: Date of Application, 29th July, 1891-Accepted, 17th Oct., 1891
COMPLETE SPECIFICATION.
Improvements in Screw Propellers for Steam Ships.
We, CHARLES MYERS, of Philips Park Road, Beswick, Manchester, in the
County of Lancaster, Designer, ELIZABETH MYERS, of the same place, and
JOHN DAVIES, of Princess Street, Manchester, aforesaid, Gentleman, 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 improved screw propellers for steam ships and has for
its object to provide for the more general utilization of looped blades to screw
propellers.
It has been found desirable in some instances or under certain conditions to
apply only two looped blades to one propeller but in propellers of large diameter
this is objectionable consequent upon the vibration which is set up in the propeller
and propeller shaft by the distance between the blades as they strike the water and
it is to obviate this that the present invention is designed.
It consists essentially of a propeller constructed with two looped blades such as
are the subject matter of Letters Patent granted in the year 1888 to Campbell
Forrest and Charles Myers and numbered 12730 and of Letters Patent granted in
the year 1891 to Charles Myers and Matthew Wells and numbered 670, and two
flat or ordinary blades placed alternately upon the same hub or centre.
It will be fully described with reference to the annexed drawings.
Fig. 3, plan.
In carrying out the invention the propeller is constructed with a central hub
or boss A of ordinary construction to which are bolted or otherwise attached the
blades.
The two blades B and C are constructed of flat helically disposed loops both
ends of which are attached to the boss one in advance of the other thus forming a
severed loop composed of the radial arms a and b connected together by an outer
segmental piece c enclosing an opening D through the centre of the blade. And
the two blades E and F are constructed of the ordinary flat spiral or twisted blade
of any shape in common use upon screw propellers for ships.
It will of course be understood that if desired in a two bladed propeller one
looped blade and one plain flat blade of ordinary type may be used, and in a three
bladed propeller one looped blade with two plain flat blades or two looped blades
with one plain flat blade may be used but we do not consider that either of
these will be equal to and at present we prefer the arrangement shown in the
drawings.
The blades as before stated are preferably bolted to the hub or centre but may
be cast in one piece therewith or otherwise attached thereto. And they may if
desired be provided with mechanism for turning them upon their axis to alter the
pitch technically known as feathering. Further they may be of any desired pitch
or dimensions.
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 :-
1. A screw propeller for steam ships having two looped blades of the form
shown and two Hat ordinary blades placed alternately upon the same hub or centre
auhotantielle on desanihod

page_text: 2. A screw propeller for steam ships with looped blade or blades in combi-
nation with plain flat blade or blades constructed and arranged substantially as
described and shown.
Dated this 27th day of July 1891.
WM. P. THOMPSON & Co.,
Manchester, Liverpool, and London; Patent Agents.