An Improved Propeller for Ships.
Year: 1898

page_text: Date of Application, 1st Nov., 1898-Accepted, 3rd Dec., 1898
COMPLETE SPECIFICATION.
An Improved Propeller for Ships.
I, PAUL GENTHE, Merchant, Kirchstrasse, 1, Westerhusen, A/E, Germany, 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 propellers of the class wherein flap valves are used.
Such propellers, as hereinbefore constructed, have had their valves projecting freely
into the water with the result that they are very liable to be damaged and their
efficient working thereby impaired. In the present invention the valves are
surrounded by a frame which is provided with wheels or rollers capable of running
upon rails or rods fixed to the vessel. This arrangement besides serving to protect
the propeller valves from damage insures that the propeller itself will work
properly.
Another feature of the invention is the gear for reversing the valves which is a
great improvement upon the arrangements heretofore known.
And in order that my said invention may be properly understood I have here-
unto appended two explanatory sheets of drawings which illustrate the new
propeller.
Fig. 1 shows the propeller in back end elevation with the protecting plate for the
cam e removed.
Fig. 2 is a section taken on the line - Fig. 1.
Figs. 3, 4, and 5 are cross sections of the propeller showing the valves in different
positions and taken on the line x-x of Fig. 1. Fig. 3 shows the position of the
valves when the vessel is going ahead, Fig. 4 the position of the valves when the
vessel is stationary, and Fig. 5 the position of the valves when the vessel is going
astern.
Fig. 6 is a horizontal section of the stern of the vessel taken on the
line y-y Fig. 7 and showing the propeller at the end of its back stroke.
Fig. 7 is a vertical section of the stern of the vessel and showing the propeller at
the end of its forward stroke.
Figs. 8 and 9 are cross sections showing the arrangement for supporting the
sliding frame at the stern of the vessel.
Fig. 10 is an enlarged view of the steam cylinder with its piston rod and
controlling gear.
The new valve propeller consists of a rectangular frame b which has, at its centre,
two vertical cross bars or bridges c arranged parallel to each other. Hinged, at their
upper edges, within the frame b are two iron plates & which constitute flap valves
and which can, when necessary, be held in position by means of a frame ƒ capable
of sliding within slots h in the frame b. This frame f can be raised and lowered by
the action of a came working within a rectangular slot or opening e¹ cut in the
r...

page_text: upward extension g of the frame. This upward extension g works in guides in the
cross bars c, c, of the frame b. When the cam is in the position indicated at Fig. I
the frame fis forced downwards to the bottom of the slots h (as shown at Fig. 4)
so that the flap valves d can swing freely to and fro within the frame b. When the
eccentric is turned round, with its longest radius in the upper position, the frame f
is raised up to the top of the slots h, as indicated at Figs. 3 and 5, so as to prevent
the flap valves & swinging to and fro within the frame b. The frame f, when raised
up, practically serves as a stop or check for the valves d.
(see
The frame b, which is provided with wheels i, runs upon angle-iron rails
Figs. 6 to 9) which are carried by the suspension bars m secured to the bottom of
the vessel, at the stern, below the water line. These angle iron rails k extend back-
wards in lines parallel with the keel and on the same level with it. Of course, in
order to leave a space for the propeller to work in, the stern frames of the ship are
not carried right down to the keel / but merely down to a false keel n.
The frame b is moved backwards and forwards by means of the piston o (see
Figs. 6, 7 and 10) of the steam cylinder r which is arranged at the stern of the
vessel. The piston rod p is hollow and passes out through a tube q in which it
works watertight. The tube q, which is provided with a stuffing box, is carried by
the short stern post s extending from the false keel n to the real keel . The end of
the piston rod p is fastened securely to the frame b. Passing through the cylinder
cover t, the piston o, and into the hollow piston rod p, is a hollow rod which,
whilst it cannot be moved longitudinally, can be turned about its axis by means of
a hand lever n². There is fitted within the tubular rod va square block m² having
connected to it a rod 82 whose outer end has the cam e fitted on it. The block m²
can slide back and forward within the tube v and the arrangement is such that when
the tube is turned by the hand lever n² the rod 82 will also be turned. In this
manner, by turning the lever n² and the rod 82, the eccentric e can be moved so as
to raise or lower the frame f into any of the positions indicated at Figs. 3 to 5. An
indicator w may be fitted on the cylinder cover and have marks on it which correspond
to the different positions of the cam so that the engineer can tell, at a glance, the
proper position in which to turn the hand lever n².
When the vessel is lying at rest the frame f is moved to the position shown at
Fig. 4 so that the valves & can freely swing backwards and forwards without exercising
any influence on the vessel. When the engineer is signalled to go "ahead" he
turns the lever n² to an extent sufficient to bring the frame fin front of the valve d
as shown at Fig. 3. When the piston takes a backward stroke the result is that the
valves, as they cannot move forward owing to the frame f, press back the water, and
so urge the vessel forward. When it is desired to reverse the motion of the ship the
engineer turns the lever n² so that the frame f is lowered into the position shown at
Fig. 4 and as the backward motion of the piston continues the valves are forced
forward by the water into the position Fig. 5 when the engineer immediately again
turns the lever n² and raises the frame f up to the top of the slots h and at the back
of the valves. Now when the piston makes its next forward stroke the valves will be
pulled through the water with the result that, as the valves cannot now swing back-
wards owing to the frame f, the vessel will be forced to go astern.
If desired more than one propeller of this description may be used on the ship.
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
consider novel and desire to claim is :-
1. A propeller for vessels characterized by flaps (d) hinged to a frame (b) capable
of moving to and fro upon rails or rods carried at the stern of the vessel, the said
flaps being locked in position, whenever necessary, by means of a movable frame (f)
carried in the frame (b) aforesaid, substantially as herein before described with
reference to the drawings annexed.
2. The mechanism for raising and lowering the frame (f) consisting of the
tube (v), turnable by means of a lever, and a rod (²), passed through the hollow

page_text: piston rod of the engine and having at its end a cam (e) which works within a slot
made in the frame (f), substantially as hereinbefore described with reference to the
drawings annexed.
1000
H. D. FITZPATRICK,
100, Wellington Street, Glasgow, Agent.