Improvements in Apparatus for Propelling Ships.
Year: 1890

page_text: Date of Application, 11th Dec.. 1890
Complete Specification Left, 22nd Aug., 1891-Accepted, 17th Oct., 1891
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Propelling Ships.
I, CHARLES EDWARD AUSTIN of 1 Westminster Chambers, Victoria Street in
the City of Westminster, Civil Engineer, do hereby declare the nature of this
invention to be as follows:-
In the Specification of a former Patent granted to William Burchall and myself
dated the 8th day of August 1885, No. 9472, is described an apparatus for
propelling ships in which there is a rectangular tube open to the water at both
ends and running longitudinally along the ship. This tube has within it a flexible
sheet to which a wavelike motion is given so that each point of the sheet reciprocates
to and fro between two opposite sides of the tube, thus forcing the water along the
tube and so propelling the ship. In that Specification the flexible sheet was driven
by a number of similar cams fixed at equal distances apart along a common shaft,
the projections of the cams being set at equal angles in advance of each other
those at the two ends of the shaft being opposite, that is to say, 180 degrees
apart.
The
By this arrangement the sheet was only in simultaneous contact with the opposite
sides of the tube at two moments during each revolution of the cams and at all
other moments the tube was partially open to the free passage of the water.
sheet, therefore, had little more control over the water than an ordinary screw
propeller.
According to this invention the two end cams are nearly in the same position on
the shaft, that is to say, include an angle of somewhat more than 360 degrees, the
other cams being equally spaced between them, so that now the sheet is always in
contact with all the four sides of the tube and therefore instead of causing propul-
sion merely by an undulatory motion through the water in the tube as in the
before mentioned Specification, by this improvement the sheet has complete control
of the water in the tube in a similar manner to the piston of a pump and when in
motion forces it out at either end.
In order to effect the revolution of the cams with the minimum friction and shock
the sum of the equal angles at which the cams are set in advance of each other is
made to exceed 360 degrees by an amount proportional to the number of cams used
so that no two cams can be over centre at the same moment.
Dated this Eighth day of December 1890.
C. E. AUSTIN...
COMPLETE SPECIFICATION.
Improvements in Apparatus for Propelling Ships.
I, CHARLES EDWARD AUSTIN, of 1 Westminster Chambers, Victoria Street,
in the City of Westminster, Civil Engineer, 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 a former Patent granted to William Burchall and
myself dated the 8th day of August 1885, No. 9472, is described an apparatus
for propelling ships in which there is a rectangular tube open to the water at
both ends and running longitudinally within and through the ship. This tube
has within it a flexible sheet to which a wavelike motion is given so that each
point of the sheet reciprocates to and fro between two opposite sides of the tube,
[D7

page_text: '
thus forcing the water along the tube and so propelling the ship. In that
Specification the flexible sheet was driven by a number of similar cams fixed at
equal distances apart along a common shaft, the projections of the cams being
set at equal angles in advance of each other those at the two ends of the shaft
being opposite, that is to say, 180 degrees apart.
By this arrangement the sheet was only in simultaneous contact with the
opposite sides of the tube at two moments during each revolution of the cams
and at all other moments the tube was partially open to the free passage of the
water. The sheet, therefore, had little more control over the water than an ordinary
screw propeller.
According to this invention the two end cams are nearly in the same position
on the shaft, that is to say, include an angle of somewhat more than 360 degrees,
the other cams being equally spaced between them so that now the sheet is
always in contact with all the four sides of the tube and therefore instead of
causing propulsion merely by an undulatory motion through the water in the
in the before mentioned Specification, by this improvement the sheet
has complete control of the water in the tube in a similar manner to the piston
of a pump and when in motion forces it out at either end.
tube as
In order to effect the revolution of the cams with the minimum friction and
shock the sum of the equal angles at which the cams are set in advance of each
other is made to exceed 360 degrees by an amount proportional to the number
of cams used so that no two cams can be over centre at the same moment.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a longitudinal section of an apparatus constructed according to my
invention and
Figure 2 is a modification of the same.
Figures 3, 4 and 5 are transverse sections of different forms of vessel showing
the manner in which my invention is to be applied to them.
Figure 6 is a detail view showing one of the cams.
The cams c communicate movement to the sheet or blade b in the tube t by
impinging on rollers set in frames forming part with the rods which passing
through glands in one side of the tube are hinged to the sheet or blade.
These frames embrace the shaft s which acts as a guide to their movement
and the friction between them is minimised by intermedial loose collars d on the
shaft which roll under the edges of the frames.
The sheet or blade in the tube is formed of separate plates of steel, nickel
steel or other suitable metal doubled over and rivetted together in the middle
and cut into tea-chest hinges at both ends; each plate enclosing part of a
continuous sheet of india rubber leather or other durable elastic material,
stretching from end to end of the sheet or blade, cut away to make room for
the hinges but extending in width beyond them, so as to touch the sides of the
tube. One pin suffices to complete the hinge which joins each separate plate
to its neighbour as well as to the rod which actuates its movement.
Constructed in this manner the rods are hinged within the substance of the sheet
or blade and there are no projections from either surface to impede the flow of
the water through the tube.
In the arrangement shewn at Figure 2 there are two sheets worked by two
sets of rods actuated by pairs of cams upon common axes.
The cams are formed of a right hand and a left hand segment of an archi-
medeán spiral that is to say of curves represented by the equations a +60
and ra- 60, 0 varying between 0° and 180° in the one case and 0° and - 180°
in the other. In these equations is the distance of any point on the curve
from the centre of the cam shaft, 0. the angle which the line joining the point
on the curve to the centre of the cam shaft makes with a fixed line passing
through the centre of the cam shaft, a the distance of the smallest part of, the

page_text: cam from the centre of the cam shaft, the throw of the cam being equal to the
length of the circumference of a circle having b as its diameter.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Apparatus for propelling ships in which there is a rectangular longitudinal
tube open to the water at both ends having within it a flexible sheet to which a
wavelike motion is given so that each point of the sheet reciprocates to and fro
between two opposite sides of the tube in such manner that the sheet is always in
contact with the opposite sides of the tube substantially as described.
2. Apparatus for propelling ships substantially as described and shown in the
drawings.