Improvements in Signal Alarm Guns.
Year: 1891

page_text: Date of Application, 20th Apr.. 1391
Complete Specification Left, 20th Feb., 1392-Accepted, 20th Apr., 1892
Improvements in Signal Alarm Guns.
I WILLIAM SPIERS FREEMAN Engineer Invicta Works Otford Kent do hereby
declare the nature of this invention to be as follows:-
This invention has more especially for its object the construction of a signal
aların apparatus for the detection and scaring of poachers, burglars, orchard
stealers, trespassers & thieves and for giving distress or other signals at sea, or
for military outpost duty & other purposes to which an alarm gun or signal may
be employed.
Alarm guns as usually made for using a breech-loading central fire cartridge
consists of (1) a short barrel closed by a breech screw through which a loose pin
or striker passes (as made by Burgess previous to 1883) the cartridge being
exploded by the said barrel & loose pin falling on to a weight or vice versa the said
barrel or weight being guided in its descent by an iron rod stuck in the ground. (2) A
Somewhat similar but improved arrangement by Burgess (see his Patent dated
Jan. 18th 1883 No. 307 which discarded the screw breech block and substituted
therefor a plain sliding breech block & pin or striker, but still retaining the iron
guide rod.
In my invention I dispense entirely with the iron guide rod substituting
therefor a strong metal tube as the guiding arrangement which said tube may
be of any desired length according to the required drop necessary to ensure the
firing of the cartridge.
The simplest form of my invention consists of a plain metal tube of such a size
that a central fire cartridge may just be a dropping fit therein, the bottom of this
tube is plugged with a solid screwed metal plug having projecting from its centre
a fixed striker or firing pin preferably standing about above the breech plug
inside the guide barrel. The metal plug may be fixed to a metal base or stand to
give stability to stand upon the ground or floor or the base may be dispensed
with and the barrel lashed or fixed to a post, stick, or tree to secure it in a vertical
position. Holes are drilled through the guide barrel immediately in a line with
the top of the breech plug to allow the air to escape when the cartridge is falling
so as not to retard its descent and consequent force with which it would strike the
firing pin when it reached the bottom. At a distance from the top of the guide
barrel corresponding with the depth of the cartridge used, is drilled a hole to take
the trigger pin which latter being passed loosely through the hole supports the
cartridge; on the withdrawal of the trigger pin when the trespasser comes in
contact with the string or wire attached thereto the cartridge falls to the bottom
of the guide barrel and explodes by coming in forcible contact with the firing pin
or striker projecting from the breech block.
The second form of my invention consists of a guide barrel preferably of the
same relative size to the cartridge as the first form but the guide barrel is drawn
in at the bottom by a ring or liner so as to retain the rim of the cartridge which
in this arrangement is intended to shoot down instead of up the guide barrel
being supported on a short tripod or other means of allowing the explosive gases
to readily escape beneath the gun. The cartridge is fired by the dropping of a
solid plunger or piston thereon having a firing pin or striker projecting from the
centre of the end thereof & guided to strike the cap or detonator of the cartridge by
sliding down the guide barrel into which the said solid plunger or piston is a dropping
A rectangular groove is cut into and around the plunger or piston about 'deep
into which groove fits loosely a flat trigger plate which said trigger plate rests upon
fit.

page_text: the top of the guide barrel to support the plunger or piston when the gun is set ready
for action. The withdrawal of the trigger plate by the string attached thereto allows
the piston to drop and thus fire the cartridge, as before. A hole is bored through
the guide barrel just below the cartridge & provided with a pin as in the first
arrangement this forms a safety pin or a secondary heavy pull trigger as desired.
The plunger is made of sufficient weight to resist the recoil. Air vent holes are
provided as in the first form at the bottom of the guide tube to relieve any pressure
or resistance to the falling of the piston or plunger.
The third form of my invention & the one I prefer consists of a guide tube as
before but instead of the cartridge alone dropping as in the first plan place the
cartridge in an auxiliary firing barrel or hollow plunger which is a dropping fit in
the guide barrel, the inside bore of the said firing barrel or plunger corresponding
with the diameter of the cartridge & of such a fit that the cartridge will not drop
out of the firing plunger when the latter is supported in its firing position by the
trigger at the top of the guide barrel as in the second plan. The advantages of
this arrangement of an auxiliary firing plunger are as follows. (1) A much shorter
guide barrel may be used consequent on the extra striking force the extra weight
of the firing plunger gives to the cartridge. (2) Much greater strength as the
firing barrel or plunger can be made of any required strength. (3) The cartridge
cases are not destroyed by bursting as in the first plan. (4) The reloading is
simplified as the short firing barrel drops out of the guide tube when inverted.
(5) A very sensitive trigger and a perfectly safe safety pin passing through the
guide barrel which latter may also be used as a coarse pull trigger if desired. The
sensitive trigger firing arrangement may be more minutely described as follows:
The trigger consists of a flat piece of sheet metal of a triangular or other suitable
shape preferably about thick with a hole or holes therein wherewith to attach
the pulling off string or wire, this trigger plate fits loosely into a rectangular
groove turned in the outside and around the firing plunger to a depth of about
one half the thickness of the walls of the said plunger. The trigger plate
being placed in the said groove the firing barrel or plunger is lowered into the
guide barrel until the trigger plate rests on the top of the guide barrel thus
supporting the plunger. On the withdrawal of the trigger plate the firing barrel
drops to the bottom of the guide barrel & the cap of the cartridge coming in
contact with the firing pin in the breech plug the cartridge explodes. Air vent
holes are provided in this arrangement as in the other two plans.
In each of the foregoing arrangements a thin stamped metal cap fits loosely over
the top of the barrel to keep out wet & moisture.
I use the first and third arrangements for visible signals in conjunction with the
audible alarm by providing a strong stamped metal shell to fit the particular size
of signal alarm gun, preferably shaped in the form of the letter U (inverted) to
withstand the force of the explosion & filled with any of the usual star compounds
as used in pyrotechnic displays. These shells may be kept separate from the blank
cartridge and dropped into position for firing when required for night duty.
Dated this the 17th day of April 1891.
COMPLETE SPECIFICATION.
Improvements in Signal Alarm Guns.
I WILLIAM SPIERS FREEMAN Engineer of Invicta Works Otford Kent 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 5
statement :-
This invention has more especially for its object the construction of a signal
alarm apparatus for the detection and scaring of poachers, burglars, orchard

page_text: stealers, trespassers & thieves and for giving distress or other signals at sea or
on land for military outpost and other purposes to which an alarm gun may be
employed.
Alarm guns as usually made for using a breech loading central fire cartridge
consists of (1) a short barrel closed by a breech screw through which a loose pin
or striker passes (as made by Burgess previous to 1883) the cartridge being
exploded by the said barrel and loose pin falling on to a weight or rice rersu the
said weight or barrel being guided in its descent by a metal rod stuck in the
ground. (2) A somewhat similar but improved arrangement by Burgess (see his
Patent dated Jan. 18 1883 No. 307 which discarded the screw breech block and
substituted therefor a plain sliding breech block and pin but still retaining the
metal guide rod. (3) similar arrangement to that of Burgess but with a hit
and miss breech closing arrangement patented by l'errin May 13 1885 No. 5871
still retaining the metal guide rod.
In my invention I dispense entirely with the metal guide rod substituting
therefor a strong metal tube as the guiding arrangement which said tube may be of
any desired length according to the required drop to ensure the firing of the
cartridge.
7
The simplest form of my invention consists of a plain metal tube of such a
size that a central fire cartridge may just be a dropping fit therein the bottom of
this tube is plugged with a solid screwed metal plug having in its centre a fixed
striker or firing pin projecting about above the breech plug inside the guide
barrel, the metal plug may be fixed to a metal base or stand to give stability to
stand upon the ground or floor or the base may be dispensed with and the barrel
Inshed or fixed to a post, stick or tree to secure it in a vertical position. Holes
are drilled through the guide barrel immediately in a line with the top of the
breech plug to allow air to escape when the cartridge is falling so as not to retard
its descent and consequent force with which it would strike the firing pin when it
reached the bottom. At a distance from the top of the guide barrel corresponding
with the depth of the cartridge used is drilled a hole to take the trigger pin
which latter being passed loosely through the hole, supports the cartridge. On
the withdrawal of the trigger pin when the trespasser comes in contact with the
string or wire attached thereto the cartridge falls to the bottom of the guide
barrel and is fired by coming forcibly in contact with the firing pin or striker
projecting from the barrel block.
The second form of my invention consists of a guide barrel preferably of the
same relative size to the cartridge as the first but the guide barrel is drawn in at
the bottom by a ring or liner so as to retain the rim of the cartridge which
in this a rangement is intended to shoot down instead of up the guide barrel
being supported on a short tripod or other means of allowing the explosive gases
to escape. The cartridge is fired by the dropping of a solid plunger or piston
thereon having a firing pin or striker projecting from the centre of the button
end thereof & guided to strike the cap or detonator of the cartridge by the guide
barrel; into which the said solid plunger or piston is a dropping fit. A rectangular
groove is turned into and around the plunger about 7 deep into which groove fits
loosely a flat trigger plate which said trigger plate rests upon the top of the
guide barrel to support the plunger when the gun is set ready for action. The
withdrawal of the trigger plate allows the plunger or piston to drop and fire
the cartridge as before. A hole through the barrel guide provided with a pin
as in the first arrangement forms a safety pin or secondary firing trigger as desired.
The plunger is made of sufficient weight to resist the recoil. Air vent holes are
provided as before at the bottom of the guide barrel to relieve any pressure or
resistance on the falling of the piston or plunger.
The third form of my invention & the one that I prefer consists of a guide tube
as before and instead of the cartridge alone dropping as in the first plan I place
the cartridge in an auxiliary firing barrel or hollow plunger which is a dropping fit

page_text: in the guide barrel the inside bore of the said firing barrel or plunger corre-
sponding with the diameter of the cartridge & of such a fit that the cartridge will
not drop out of the firing plunger when the latter is supported in its firing position
at the top of the guide barrel by the trigger plate as in the second arrangement.
The advantages of this arrangement of auxiliary firing barrel or plunger are as
follows. (1) much shorter guide barrel may be used consequent on the extra
striking force the extra falling weight of the firing-barrel or plunger gives to the
cartridge. (2) Much greater strength as the firing barrel or plunger can be made
of any strength required. (3) The cartridge cases are not destroyed by bursting
as in the first plan. (4) Reloading is simplified as the short firing barrel drops
out of the guide tube when inverted. (5) A very sensitive trigger and a perfectly
safe safety pin passing through the guide barrel which latter may also be used as a
coarse pull trigger if desired.
0
The sensitive trigger firing arrangement may be more minutely described as
follows. The trigger consists of a Hat piece of sheet metal of a triangular or
other suitable shape preferably about thick with a hole or holes therein where-
with to attach the pulling off string or wire this trigger plate fits loosely into a
rectangular groove turned in the outside of the firing barrel or plunger to a depth
corresponding to about one half the thickness of the walls of the said plunger.
The trigger plate being placed in the said groove the firing barrel or plunger is
lowered into the guide barrel until the trigger plate rests on the top of the guide
barrel thus supporting the firing barrel or plunger on the withdrawal of the
trigger plate the firing barrel drops to the bottom of the guide barrel & the cap of
the cartridge coming in contact with the firing pin in the breech plug the explosion
of the cartridge is effected. Air vent holes are provided in this arrangement as in
the other two plans.
The guide tube or barrel may be made shorter and more compact if desired, and
the plunger or firing barrel made longer than the guide tube, in which case I use
two small spiral springs or rubber bands attached to opposite sides (diametrically)
of the firing barrel (top) and to the bottom part of the guide tube by means of
four buttons or studs, two on the firing plunger and two on the guide barrel by
which means also the gun may be fired in any position, or a single spiral spring
may be inserted between the firing barrel or plunger and the guide tube, thrusting
against an annular lip projecting round the inside of the guide tube at the top and
against a lip projecting round the inside of the firing barrel or plunger at the
bottom the said spring being compressed when the firing barrel is pulled up and
set in its firing position.
The action of the gun will be made clear by reference to the drawing, where
a represents the guide barrel.
the firing plunger which is an easy fit within the guide barrel a.
the trigger plate resting in the annular groove cut in the firing plunger.
the safety pin to prevent the firing plunger descending by accident whilst
setting the trigger plate.
the central fire cartridge shewing shell at top, then the wad, powder and cap
in the head thereof, against which latter the firing pin g strikes.
signal star * consisting of a strong metal case y, star composition .r, wad ir,
fuse hole, fuse or quick match.
firing pin fixed in centre of breech plug.
hair vent holes to prevent the cushioning of the firing plunger.
7 metal hast or support.
/louse weather cap of thin sheet metal to keep out wet.
cord or wire attached to the trigger plate and stretched along the line of
expected tre passer or thief.
use the first and third arrangements for visible signals in conjunction with the
audible alarm by providing a strong stamped metal shell to fit the particular size
of signal alarm gun preferably shaped in the form of the letter U (inverted) to

page_text: withstand the force of the explosion and filled with any of the usual star com-
pounds as used for rocket stars, roman candles & pyrotechnic bomb shells, these
shells may be kept separate from the blank cartridge and dropped into their place
when desired for night duty.
Having thus described the nature of my invention and the manner of performing
the same I claim
First The use of a tube guide barrel in conjunction with a central fire cartridge
fired by dropping of its own weight on to a firing pin at the bottom of the barrel
guide as hereinbefore described.
:
Secondly The use of a tube guide barrel to guide a solid plunger or piston
with its firing pin on to an inverted central fire cartridge as herein before described.
Thirdly The use of a tube guide barrel in conjunction with a hollow firing
piston or plunger containing the cartridge as hereinbefore described with or without
accelerating springs.
Fourthly: The use of a strong stamped metal shell for use with the above as
hereinbefore described.
In witness whereof I have hereunto set my hand this the Eighteenth day of
abruare 1809
WM. S. FREEMAN.