NEW OR IMPROVED ALARUM APPARATUS FOR USE BY SHIPS OR VESSELS AT SEA
Year: 1876

page_text: LETTERS PATENT to William Walker, of the City and County of Aberdeen,
North Britain, for the Invention of "NEW OR IMPROVED ALARUM APPARATUS
FOR USE BY SHIPS OR VESSELS AT SEA."
Scaled the 14th October 1876, and dated the 15th April 1876.
PROVISIONAL SPECIFICATION left by the said William Walker at the Office
of the Commissioners of Patents on the 15th April 1876.
"NEW
WILLIAM WALKER, of the City and County of Aberdeen, North Britain.
OR IMPROVED ALARUM APPARATUS FOR USE BY SHIPS OR VESSELS AT SEA."
This Invention which relates to new or improved pneumatic fog alarum appa-
ratus is for use in or by ships or vessels at sea to enable the officers or other persons
on board to distinguish their relative positions with other vessels during the exis-
tence of a fog or in snow storms so as to avoid the danger of collisions.
The alarum apparatus constituting this Invention consists of an air pump, whose
barrel or cylinder is provided with a tubular piston or plunger, and with a handle
for raising or lifting the piston or plunger during its upward stroke, and whereby
air is drawn into the pump.
The lower extremity of the piston or plunger is provided with a valve for the
admission of air, and circular weights are placed above this valve by which the
piston or plunger may be loaded to any desired extent, these having a central hole
through the through which the air passes to the valve. According to the extent
to which the piston or plunger is loaded, so during its descent does that regulate
the pressure and rate of discharge of the air from the pump into the alarum part of
the apparatus. In order to ensure the lower part of the piston or plunger fitting
the barrel or cylinder of the pump air-tight, this lower part perforated with holes
over which an elastic cylindrical ring of india-rubber is fixed.
The perforations and the elastic ring are below the air valve, so that when the
piston or plunger descends the compressed air acting through the perforations on
the elastic ring blows it outwards or expands it against the sides of the pump
barrel, and when the plunger is lifted upwards the expansion of the elastic ring
ceasing allows it to be easily raised by virtue of the diminished friction against
the sides of the pump.
The sounding part of the apparatus consists of a sounding reed having a silver
tongue or vibrator attached to the trumpet by a disengaging screw, and contained
within the air tube leading from the pump to the joint in the horn or trumpet.

page_text: The horn or trumpet is formed in two parts, the upper part with its revolvable
cowl, and the lower part, these two parts being connected together by a conical
telescopic joint, by which the upper part slides upon the lower so as to be shut
down when not in use.
An adjustable arm and guide with a pinching screw are also attached to the
upper part of the horn or trumpet for fixing the cowl head and upper part of the
horn or trumpet in position for sounding an alarum.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said William Walker in the Great Seal Patent Office on the 14th October
1876.
"
WILLIAM WALKER, of the City and County of Aberdeen, North Britain. << NEW
OR IMPROVED ALARUM APPARATUS FOR USE BY SHIPS OR VESSELS AT SEA."
My said Invention, which relates to new or improved pneumatic fog alarum
apparatus, is for use in or by ships or vessels at sea to enable the officers or other
persons on board to distinguish their relative positions with other vessels during
the existence of a fog or in snow storms so as to avoid the danger of collisions.
And in order that my said Invention may be properly understood, I now proceed
more particularly to set forth the system, mode, or manner in, or under which the
same is or may be used or practically carried into effect,.reference being had to the
annexed Sheet of Drawings and to the letters and figures marked thereon; that is
to say,-
On the Sheet of Drawings hereunto annexed, Figure 1 is a vertical section, and
Figure 2 a side clevation of the alarum apparatus constituting my said Invention,
and which consists of an air pump A, whose barrel or cylinder is provided with a
truncated or tubular piston or plunger B having a handle or bar C for raising it
during its upward stroke, in effecting which air is drawn into the barrel of the
pump. The lower extremity of the piston or plunger B is provided with a flap or
other valve D for the admission of air into the barrel A, and circular weights E are
placed above the valve D on the bottom of the plunger by which it is loaded to any
desired extent. The weights have holes made through their centres for the passage of
air to the valve D, as seen at a, Figures 1 and 3, which latter Figure is an enlarged
detailed view of a portion of the pump barrel A, and of the piston or plunger B.
According to the extent to which the piston or plunger is loaded, so during its
descent does that load regulate the pressure and rate of discharge of the air from
the pump to the alarum part of the apparatus. In order to ensure the lower part
of the piston or plunger fitting the barrel or cylinder A of the pump air-tight, the
said lower part is perforated with holes over which an elastic cylindrical ring c of
india-rubber is placed, being held in position by flanches or rings & formed on or
fixed to the piston, or the ring may be so held by binding wire around its upper
and lower edges, or by other equivalent means. The perforations and the elastic
ring are placed below the valve D, so that when the piston or plunger descends and
the valve closes the compressed air acting through the perforations on the elastic
ring blows or bulges it outwards, whereby it is expanded against the sides of the
pump barrel A, thereby making an air-tight joint therewith. When the plunger is
lifted upwards and the valve D opens, the expansion of the elastic ring ceasing
allows the plunger to be casily raised by virtue of the diminished friction against the
sides of the pump' barrel A.
The alarum or signalling part of the apparatus consists of a sounding reed f
seen at Figure 1, and in enlarged detail at Figure 4 of the Drawings. The reed
which is placed within an air tube H leading from the pump to the lower part of
the horn or trumpet I is attached by a screwed portion at its upper end to the
said trumpet, and it is provided with a tongue or vibrator g, as shewn. The tongue
or vibrator is composed of silver, whereby greater, purity of tone, flexibility, and

page_text: imperviousness to atmospheric influences are obtained than with the materials
hitherto used for the vibrators of reeds. The horn or trumpet is screwed or other-
wise fixed in the upper end of the tube H, and it is formed in two parts connected
together by a conical telescopic joint at J, by which arrangement the upper part
slides upon the lower one so as to shut down into the position shewn at Figure 2,
when the apparatus is not in use. The tube H is encased within a shield L to
protect it and the reed f, and by the said shield support is also given to the lower
part of the horn or trumpet I, which at its upper end is provided with a cowl M
revolvable in any desired direction. An arm having at one end a guide 7 with a
pinching screw, and working in or on a slide 8 on the side of the pump barrel A, is
attached to the upper part of the horn or trumpet I, for fixing it with the cowl head
in position for sounding an alarum, or any other equivalent arrangement of mechanism
may be used for that purpose.
The apparatus herein-before described may be made of different sizes according
to the size of the ship or vessel on which it is to be employed, and it may be
constructed from tin, zinc, brass, copper, or other metal, or of a combination of
metal with wood or other material.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in, or under which the same is or may
be used or practically carried into effect, I would observe in conclusion, that what
I consider to be novel and original, and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is-
First. The new or improved alarum apparatus constructed and arranged sub-
stantially as herein-before described and shewn on the Sheet of Drawings hereunto
appended, and the employment thereof, as and for the purpose set forth.
Second. The hollow or truncated piston or plunger B, provided with a valve D,
with moveable regulating weights E, and packed by an india-rubber or other elastic
ring c, in the manner herein-before described with reference to Figures 1 and 3 of
the annexed Drawings.
Third. The telescopic trumpet or horn I.
Fourth. The air tube H with its connexions arranged substantially as set forth.
Fifth. The silver tongue or vibrator g for the sounding reed.
In witness whereof, I, the said William Walker, have hereunto set my hand
and seal, this Tenth day of October One thousand eight hundred and seventy-
WILLIAM WALKER. (L.S.)