Double Door for Ships' Bulkheads.
Year: 1895

page_text: Date of Application, 11th Feb., 1895-Accepted, 16th Mar., 1895
COMPLETE SPECIFICATION.
Double Door for Ships' Bulkheads.
We, MARTIN STÜHLER of 1 Magnusstrasse, Cologne, Kingdom of Prussia,
German Empire, Mathematician, and CARL THEODOR DÖRR of 33 Pfeilstrasse,
Cologne aforesaid Doctor of Philosophy, 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:-
The present invention relates to a double door consisting of two single doors,
for closing passage openings of ships' bulkheads in a water-tight manner, and its
main feature consists in the fact that the two single doors, of which there is one
on either side of the wall of the bulkhead, and of which each door is designed to
close the entire width of the opening, are connected together in such a manner that
when one or the other door is closed, either automatically or by hand, the other
door will also be closed simultaneously. For this purpose the pivots of the doors
are arranged parallel to each other on both sides of the door opening, so that the
doors are always parallel to each other in their movement, and therefore open and
close simultaneously.
In order to effect a tight joint the edges of the doors may be provided with
holes and with jointing strips or valves situated behind the same which, when the
door is closed, and also if water should penetrate into the aforesaid holes, are
pressed against a grating provided on the wall of the bulkhead, so that the passage
of water from one bulkhead space into the next bulkhead space is completely and
securely prevented.
A double door composed of two single doors T, T, is shown diagrammatically in
Figure 1, which shows a section taken through the pivots or hinges A1 A2. The
advantage of two single doors connected together by a suitable parallel arrangement,
so as to constitute a double door, lies in the fact that the imaginary centre of
gravity P (replacing the two centres of gravity P₁ P₁) of the double door, will
not be shifted in any position, direction or movement of the latter, so that all rolling,
pitching and oscillation of the ship has no influence on the movements of the
double door.
Consequently, if the double door have imparted to it a tendency, however small,
to close itself, the said door will always remain closed, but will allow of a convenient
passage at the moment of imminent danger, and if water should enter from both
sides, it acts as it were as a double valve and indicates, by the resistance which it
opposes to its being opened, the presence of water in the adjacent bulkhead space.
The devices for keeping these single doors T, T, always parallel to each other
during their motion may be arranged at two opposite terminal points of the
prolonged pivots of the doors, and may be either single or double, that is to say
they may be arranged on one side or on two opposite sides of the opening of the
bulkhead door.
Thus, for example, Figure 2 shows an arrangement in which the door pivots are
connected together by means of a simple parallelogram.
The short sides of the latter are formed by cranks or links B, B, mounted on
the door pivots A, A, and which are connected together by means of a connecting
rod C. The fourth (imaginary) side of the parallelogram passes through the
centres of rotation of the door pivots A₁ A2.
On rotating one of the door pivots A, or A, in the direction of the arrow, the
connecting rod C will move in the direction of the arrow shown, and consequently
both doors will be moved together into the closing position.

page_text: In the arrangement shown in Figure 3, a perfectly equal or uniform distribution
of the weight of the doors is effected by providing in addition to the connecting
rod C, a second connecting rod C₁ the ends of which are mounted on the door
pivots A, A, whilst their other ends are connected to an intermediate lever D,
the pivot X of which is situated in a line connecting the two pivots A., A₂.
In the arrangement shown in Figure 4, the cranks are replaced by bent
levers A₁ A, having arms at right angles to each other, the free ends of which
are connected together by means of the two connecting rods C C₁. By employing
a right angle in the levers A," A2", a dead point is obviated.
In the arrangement shown in Figure 5, the door pivots are provided with
pulleys E E' around which passes an endless rope or chain E2 whilst in Figure 6
the pulleys are replaced by toothed wheels F F, and the endless rope or chain is
replaced by a toothed rack F₂ engaging with the said wheels.
The attachment of the door with the above described closing devices to the
bulkhead wall is shown in Figure 7, in which the door is shown in the open
position. In this case the two door pivots A, A, are carried in a watertight
manner through the suitably bent bulkhead wall S and the links A₁* A* and
connecting rods C C₁ are contained in a box G into which the prolongation of the
door pivot A, or A, extends. In the arrangement of door shown in Figure 3 the
pivot X of the intermediate lever D may be carried through the bulkhead wall S
as shown in Figure 8, and the connecting rods C, C₂ are attached to the ends of
the intermediate lever on both sides of the bulkhead wall.
The said pivot X of the intermediate lever D may also be carried through a
spring box (Figure 9) the spring in which is connected to the pivot and has a
constant tendency to close the double door. The said spring may obviously be
replaced by any other desired motive power which acts in the direction of the
arrows in Figures 2-6, upon any suitable point in the door or in the connecting
rods &c.
When it is desired to employ the weight of the doors as the closing force, their
pivots are arranged vertically and the doors themselves are arranged so as to rise
when opening, and to close when moving downwards.
In the case of double doors arranged in the deck of the ship, and situated in a
horizontal position when closed, the upper single door is made heavier, so that wheu
the door is closing the arc-shaped path of the centre of gravity of the door will
facilitate a rapid closing of the same.
In the case of flap-like double doors (see the vertical section in Figure 10) whose
pivots are arranged horizontally, and whose faces are vertical in the closed position,
it is preferable to arrange the said pivot at the upper side of the door opening
whereby a considerable closing power of the door is obtained in consequence of the
tendency of the centre of gravity to move downwards. In this case the movements
of the doors are not parallel, but are symmetrical to the bulkhead wall. These
movements are effected by means of links H, H, Figure 10, which are pivotted to
the cranks B₁ B, mounted on the door pivots. The other ends of said links H, H₂
are connected together on a pin H adapted to move in a straight line or in a special
guideway.
Each single door covers the bulkhead wall S on all four sides of the door opening
for the width of a strip r Figure 11, upon which jointing devices are arranged in a
suitable manner. These jointing devices, which are arranged around the whole of
the door, or around the door opening, may be variously constructed. Thus for
example as shown in Figure 12, which is a horizontal section on the line x-y of
Figure 11, they may consist of a box or casing I provided on the bulkhead wall,
and the sides of which situated opposite or facing the doors are formed by a fillet K
or K, and a grating L or L₁, whilst strips M M, with bulges N N, are fixed to the
end and to the commencement of the door. These strips are situated behind the
protective boxes P P₁ (provided with holes 00₁) of the doors T T₁, and bear,
when the latter are closed, upon the gratings L L₁."
Now as soon as water penetrates into that compartment of the ship, it flovs

page_text: through the holes O O₁ and presses the strips M M₁ against the gratings L L₁.
Should the pressure of the water rising in the compartment and acting against the
door become much greater, the bulges N N₁ on the strips M M₁ of the door (which
may possibly be somewhat on the skew) bear behind the ribs or fillets KK,
(provided on the edge of the bulkhead wall) whereby a tight joint is effected
independently of the joint formed by the strips M M₁.
The doors may be provided with movable handles R, which when the doors are
closed, serve to effect a locking or bolting of the latter in an automatic manner.
Having now particularly described and ascertained the nature of our said
invention and in what manner the same is to be performed, we declare that what
we claim is :-
1. A double door for ships' bulkheads, said door consisting of two single doors
situated on the two sides of the bulkhead wall, these single doors being connected
together by means of connecting rods and links, rope-, chain-, or toothed rack gear,
or the like, in such a manner that said doors move either parallel or symmetrically
to each other, and thus open and close simultaneously, and in the latter case bear
from both sides against the door frame, substantially as described.
2. In the double door specified in Claim 1, the arrangement of jointing strips at
the edges of the single doors, said strips being adapted, when water penetrates into
the several compartments of the ship, to become pressed against grating-like
openings provided along the edge of the opening in the bulkhead wall, substantially
as set forth,
Dated this 9th day of February 1895.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London, Chartered Patent Agents.