IMPROVEMENTS IN ALARM APPARATUS TO AID IN THE DETECTION OF TRESPASSERS.
Year: 1877

page_text: 5.
LETTERS PATENT to Isaac Henson, of No. 96, Whitecross Street, Derby, for the
Invention of IMPROVEMENTS IN ALARM APPARATUS TO AID IN THE DETECTION
OF TRESPASSERS.'
"
Sealed the 18th December 1877, and dated the 3rd October 1877.
PROVISIONAL SPECIFICATION left by the said Isaac Henson at the Office of
"
the Commissioners of Patents on the 3rd October 1877.
ISAAC HENSON, of No. 96, Whitecross Street, Derby.
APPARATUS TO AID IN THE DETECTION OF TRESPASSERS."
IMPROVEMENTS IN ALARM
This Invention has more especially for its object to construct an alarm signal
apparatus for the detection of poachers at night-time.
The apparatus is used in connection with a wire or wires laid along the ground,
and is so arranged that in the event of any one coming against the wire a small gun
is fired, and the attention of watchers thereby called, whilst at the same time a
rocket is let off, and ascending will be visible for a considerable distance, and will
enable the watchers to judge where the poachers are.
The apparatus is also so constructed that at the time when the signal gun is fired
the wire becomes detached from the apparatus, so that the poachers cannot find the
apparatus by feeling onwards along the wire.
For these purposes I form the apparatus of a metal rod having a disc around it
near one of its ends, and this end is pointed so that it may be stuck upright into
the ground. At one side of the rod is placed a short metal cylinder forming the
alarm gun.
The cylinder has lugs projecting from it which embrace and slide freely
upon the rod. The lower end or breech of the gun is fitted with a transverse slide,
by which it can be closed, and when the slide is drawn to one side a cartridge can
be inserted into the gun. Passing up through the centre of the slide is a pin or
striker of somewhat greater length than the thickness of the slide. When the gun
has been loaded and the breech closed, if the gun is allowed to drop down, the, rod
before mentioned, the pin, or striker will come against the disc on the rod and be
forced inwards, whereby the cartridge in the gun will be caused to explode.

page_text: At the top of the rod there is a hook catch, which, when the gun has been raised
to the upper end of the rod, hooks under the upper lug, projecting from the gun,
and holds the gun up.
The hook catch has a small trigger finger upon it, over the end of which a loop of
the wire is passed. The wire is led down to this arm through an eye in the top of
the rod. When the wire is pulled by any one coming against it the trigger will
therefore be drawn upwards, and the hook will be withdrawn from below the gun,
so allowing the gun to drop, and causing the cartridge placed in it to explode. At
the same time the wire is set free from the trigger finger and is entirely disengaged
from the apparatus, so as to prevent any one from finding the apparatus by following
along the wire.
Whilst the gun is being loaded, and whilst the wire is being adjusted on the
trigger finger, the gun is held up by the trigger, and the trigger is prevented from
rising by a small sliding safety bolt, which is afterwards withdrawn when the
apparatus has been set.
When a rocket is to be fired at the same time as the gun I form the apparatus
with a second rod standing up parallel with the first rod; this second rod carries
eyes, down through which is passed the rocket stick; the rod also carries a spring,
the free end of which can be held away from the rod by a lever catch, one arm of
which comes below the gun when the the apparatus is set. When, however, the gun is
allowed to drop it strikes the lever catch and releases the spring; the spring then
strikes against the fuse of the rocket, which is placed between it and the rod, and
ignites the fuse, and consequently fires off the rocket.

page_text: 1
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Isaac Henson in the Great Seal Patent Office on the 3rd April
1878.
"IMPROVEMENTS IN ALARM
ISAAC HENSON, of 96, Whitecross Street, Derby.
APPARATUS TO AID IN THE DETECTION OF TRESPASSERS."
This Invention has more especially for its object to construct an alarm signal
apparatus for the detection of poachers at night-time.
•
The apparatus is used in connection with a wire or wires laid along the ground,
and is so arranged that in the event of any one coming against the wire a small gun
is fired, and the attention of watchers thereby called, whilst at the same time a
rocket is let off, and ascending will be visible for a considerable distance, and will
enable the watchers to judge where the poachers are.
The apparatus is also so constructed that at the time when the signal gun is fired
the wire becomes detached from the apparatus, so that the poachers cannot find the
apparatus by feeling onwards along the wire.
For these purposes I form the apparatus of a metal rod having a disc around it
near one of its ends, and this end is pointed so that it may be stuck upright into
the ground. At one side of the rod is placed a short metal cylinder forming the
alarm gun. The cylinder has lugs projecting from it which embrace and slide freely
upon the rod. The lower end or breech of the gun is fitted with a transverse slide,
by which it can be closed, and when the slide is drawn to one side a cartridge can
be inserted into the gun. Passing up through the centre of the slide is a pin or
striker of somewhat greater length than the thickness of the slide. When the gun
has been loaded and the breech closed, if the gun is allowed to drop down, the rod
before-mentioned the pin, or striker, will come against the disc on the rod and be
forced inwards, whereby the cartridge in the gun will be caused to explode.
At the top of the rod there is a hook catch, which, when the gun has been raised
to the upper end of the rod, hooks under the upper lug projecting from the gun,
and holds the gun up..
The hook catch has a small strigger finger upon it, over the end of which a loop
of the wire is passed. The wire is led down to this arm through an eye in the top
of the rod. When the wire is pulled by any one coming against it, the trigger will
therefore be drawn upwards, and the hook will be withdrawn from below the gun,
so allowing the gun to drop, and causing the cartridge placed in it to explode. At
the same time the wire is set free from the trigger finger and is entirely disengaged
from the apparatus, so as to prevent any one from finding the apparatus by following
along the wire.
Whilst the gun is being loaded, and whilst the wire is being adjusted on the
trigger finger, the gun is held up by the trigger, and the trigger is prevented from
rising by a small sliding safety bolt, which is afterwards withdrawn when the
apparatus has been set.
When a rocket is to be fired at the same time as the gun I form the apparatus
with a second rod standing up parallel with the first rod; this second rod carries
eyes down through which is passed the rocket stick; the rod also carries a spring,
the the free end of which can be held away from the rod by a lever catch, one arm of
which comes below the gun when the apparatus is set. When, however, the gun is
allowed to drop it strikes the lever catch and releases the spring; the spring then
strikes against the fuse of the rocket, which is placed between it and the rod, and
ignites the fuse, and consequently fires off the rocket.
Figure 1 of the Drawing hereunto annexed shows a side view of an alarm
apparatus constructed as above described.
A is a square rod pointed at its lower end, and with a disc fixed to it at a distance
above the point; B is the short metal cylinder, which is free to slide up and down
on the rod A; B₁ are lugs which project from the cylinder to embrace the rod A.;
C is a hook catch which hooks under one of the lugs projecting from the cylinder,

page_text: and holds up this cylinder when it has been raised to the top of the rod; D is a
slide by which the lower end of the gun can be closed; D' is a button fastening to
retain the slide when it closes the end of the gun; E is a striker which passes up
through the centre of the slide.
When the gun is to be loaded it is raised into the position shown, and caught by
the hook catch or trigger C, and this trigger is locked by moving endwise the
sliding catch G, so that it comes above the trigger and prevents it from releasing
the gun. The slide D is then moved endwise, and an ordinary central-fire cartridge.
is inserted into the now open breech end of the gun; the slide is then moved back
into its closed position and retained by the button catch D¹. The endway to-and-fro
movement of the slide D is limited by a small pin K entering a longitudinal groove
in the upper face of the slide.
The sliding catch G is shown separately at Figure 2.
When the gun has been loaded, and whilst the trigger is still retained by the
sliding safety catch G, a loop of a wire L, which has previously been laid out as
required, is passed down through a hole M in the bent-over upper end of the rod A
and under the trigger, as shown. When the apparatus has thus been set the safety
bolt is withdrawn so as to set the trigger free, and should any person trespassing
upon the ground come against the wire the loop will be pulled up and draw the
trigger back, so letting the gun fall and causing its discharge, as before explained.
N is a rod also standing up from the disc on the rod A; it carries a spring O which
can be drawn back away from the rod into the position shown in the Drawing, and
be held in this position by the end of a trigger P being brought opposite a projection
at the side of the spring. The rod also carries two rings R to support the stick of
a rocket; the fuse of the rocket, which is prepared with a detonating material, is
laid against the rod. Should the gun be dropper by a pull on the wire the upper
lug projecting from the gun strikes the tail end of the trigger P, and turns the
trigger out of the way of the projection at the side of the spring; the spring then
flies forward towards the rod N, and, striking the rocket fuse, ignites it, and so fires
off the rocket.
Either the gun or the rocket apparatus might be employed singly, but I prefer
to employ both together,.as above described.
Having thus described the nature of my Invention, and the manner of performing
the same, I would have it understood that I claim,-
The construction of alarm apparatus, substantially as herein-before described.
Also the construction of the alarm apparatus so that when the signal gun is fired
the wire becomes detached from the apparatus, as described.
In witness whereof, I, the said Isaac Henson, have hereunto set my hand and
seal, this Second day of April, in the year of our Lord One thousand eight
hundred and seventy-eight.