CERTAIN IMPROVEMENTS IN FIRE-ARMS
Year: 1853

page_text: LETTERS PATENT to Philip Harris, of the Royal Marine Barracks,
Chatham, in the County of Kent, First Lieutenant in Her
Majesty's Royal Marine Forces, for the Invention of "CERTAIN
IMPROVEMENTS IN FIRE-ARMS."
Sealed the 20th October 1853, and dated the 21st April 1858.
PROVISIONAL SPECIFICATION left by the said Philip Harris at the
Office of the Commissioners of Patents, with his Petition, on the
21st April 1853.
I, PHILIP HARRIS, do hereby declare the nature of the said Inven-
tion for "CERTAIN IMPROVEMENTS IN FIRE-ARMS" to be as follows:-
This Invention consists in the combination of two simple mechanical
powers in one circular movement, by which a force or power of from
seven to ten or more, to one, against the resistance, may be easily and
instantaneously obtained and exerted. And the object and intention of
this Invention is to apply this principle to the construction of the
triggers of gun locks generally, for the purpose of obviating the objec-
tions attending the sudden jerk which on triggers of the ordinary

page_text: construction, and also hair triggers, is unavoidable, and by which the
aim of guns, and particularly rifles, is rendered uncertain, and, in some
cases, wholly ineffective. And, further, by employing this principle of
construction, I cause the trigger to move through more space than
hitherto, by which I obtain a slow and gradual movement of such part,
and consequently have greater command over the trigger. Moreover,
by thus constructing. the trigger, I reduce, to a very considerable.extent,
the risk of an accidental discharge, as, in the event of a twig or other
substance or 'thing catching it, the probability is that it would not hold
on to the trigger a-sufficient-length of time to cause the discharge of
the piece, and when released therefrom the trigger would resume its
original safe position. And, lastly, the power exerted by the trigger
upon the "sear" of the lock is by this Invention rendered uniform
throughout its range of action, which gives great command in dis-
charging. But, in, order to explain this Invention more fully, I will
proceed to describe the illustrative drawing hereunto annexed, explana-
tory of the principle of construction upon which this Invention.is, based,
and the mode of applying the same to the construction of triggers, as
Fig. 1, exhibits a diagram illustrative of the principle of construction
of this Invention. Eigs. 2, and 3, are side elevations of a trigger con-
structed according to this. Invention; shewing the position of the trigger
when in action and out of action. Fig. 4, is a top plan view thereof,
and of certain other parts, to which it is connected. At each of these
figures the
same letters of reference, are employed to denote .corres-
ponding parts.
The principle of construction illustrated by the diagram of Fig. 1,
is as follows Letc, b, be an' are of any number of degrees, (say
.60%), the radius, being c, d, of any length (say 1 inch); bisect
the angle. c, a, b, by d, a; produce a b, to c, and
to the elevation required in the inclined plane.
-
make e, b, equal
Where d, a, cuts
1, at g, make qf, equal to half ... By Euclid, Book 4. Pro-

page_text: position 5, find the centre h, from which, at the distance h, e, hf,
or h, c, describe the arc ef, c; then c, f, c, is a plane inclined to
the arc c g, b, and such that at half the arc g, the elevation g, f,
is half the total elevation e, h. At the end of the arc b, and at
any other point in the arc c b, the elevation will bear a similar propor-
tion to the greatest elevation. ca P, is the lever by which this circular
inclined plane is brought into action; a, being the axis or fulcrum of
said lever, and a, P, may be at any convenient angle with a, c, or a, e.
And, according to this principle of construction, it will appear manifest
that as the curved inclined plane c, f, e, is brought into action by the
lever a P, so as to raise the "sear" of the lock with which it is to be
placed in contact, the power of the trigger at any point of its range of
action will always be the same, as the loss of power consequent upon
variation of position or shortening of the lever or trigger will be com-
pensated for by the curved inclined plane. At Fig. 2, A A, marks the
trigger plate; B, a boss formed thereon, in which a screwed hole is
made to receive the screw C, which connects said trigger plate to the
stock of the gun. D D, are projections formed upon the plate. A, and
at each side of a slot through which the trigger E, passes, the same
being connected to the parts D D, by a pin or rivet a, which is the
axis upon which said trigger turns or moves. G,' is a steel spring, one
end of which is fixed upon the boss B, in any-convenient manner; and
the other and opposite end takes under the projecting part 6, of the
trigger, as shewn at Figs. 2, and 3; at which Figures, r, marks that part
of the curved inclined plane upon which the "sear of the lock rests
when the trigger is out of action; and d, marks that part of the curved
inclined plane upon which the "sear" would be at the moment of
discharge, as exhibited at Fig. 2, which shews the spring G, depressed
for the purpose of returning the trigger to its original position upon the
pressure being removed from the finger plate P. And, as an additional
security and effectual preventive against the accidental discharge of the
contents of fire-arms, it is proposed to employ a mechanical arrange-
ment, not shewn by the drawing, for rendering the trigger ineffective at
the half cock.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Philip Harris, in the Great Scal Patent Office;
on the 21st October 1853.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
PHILIP HARRIS, of the Royal Marine Barracks, Chatham, in the
County of Kent, First Lieutenant in Her Majesty's Royal Marine
Forces, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-first day of April, in the year
of our Lord One thousand eight hundred and fifty-three, in the six-
teenth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Philip Harris, Her special licence that
I, the said Philip Harris, my executors, administrators, and assigns, or
such others as I, the said Philip Harris, my executors, administrators,
and assigns, should at any time agreo with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "CERTAIN IMPROVEMENTS IN FIRE-
ARMS," upon the condition (amongst others) that I, the said Philip
Harris, by an instrument in writing under my hand and seal, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the
same to be filed in the Great Seal Patent Office within six calendar
months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Philip Harris, do hereby de-
clare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof (that is to say):
My Invention consists in the combination of two simple mechanical
powers in one circular movement, by which a force or power of from
seven to ten or more, to one, against, the resistance, may be easily and.
instantaneously obtained and exerted; the principle of construction.
consisting of a lever, one end of which is an arc of a circle, to which

page_text: is attached a circular-shaped wedge, formed of one and the same piece
of material as the said lever; the said wedge being constructed, "ad
libitum," to any desired pitch or angle, as herein-after exhibited and
described, and constituting what in Mechanics is known and distin-
guished as an excentric or cam; and the object and intention of my
said Invention is to apply this principle to the construction of the
triggers of gun locks generally, for the purpose of obviating the sudden
jerk which in triggers of the ordinary construction, and also hair
triggers, is unavoidable, and by which the aim of guns, and particularly
rifles, is rendered uncertain, and, in some cases, wholly ineffective.
And, further, by employing this principle of construction, I cause the
trigger to move through more space than hitherto, by which I obtain
a slow and gradual movement of such part, and consequently have
greater command over the trigger. Moreover, by thus constructing the
trigger, I reduce to a very considerable extent the risk of an accidental
discharge, as, in the event of a twig or other substance or thing catching
it, the probability is that it would not held on to the trigger a sufficient
length of time to cause the discharge of the piece, and when released
therefrom the trigger would resume its original safe position, by means
of a spring employed for that purpose. And, lastly, the power exerted
upon the "sear" of the lock is, by this Invention, rendered uniform
throughout its range of action, which gives great command in discharg-
ing. But in order to explain my said Invention as completely as
possible, I now proceed to describe the best means I am acquainted
with for carrying my said Invention into practical effect, reference
being had to the illustrative drawing hereunto annexed, and to the
numeral figures and letters of reference marked thereon respectively,
as follows:
DESCRIPTION OF THE DRAWING.
Figures 1, and 2, exhibit diagrams illustrative of the principle of
construction upon which my said Invention is based. Figures 3, and 4,
are side elevations of a trigger constructed according to my said In-
vention, shewing also the position of the trigger when in action and out
of action. Figure 5, is a top plan view thereof and of certain other

page_text: parts to which it is connected. Figure 6, is a modified form of con-
struction of the above-mentioned trigger. At each of the foregoing
Figures I employ similar letters of reference, to denote corresponding
parts, in so far as such parts appear or can be seen at each of the figures
respectively.
The principle of construction illustrated by the diagram at Figure 1,
is as follows: Let c, b, be an arc of any number of degrees (say 60°),
the radius being, c, a, of any length (say one and a half inch); bisect the
angle c, a, b, by d, a; produce a, b, to e, and make e, b, equal to the
elevation required in the inclined plane. Where d, a, cuts c, b, at g,
make g, f, equal to half e, b. By Euclid, Book 4, Proposition 5, find
the centre h, from which, at the distance h, e, h, f, or h, c, describe the
arc e, f, c; then c, f, e, is a plane inclined to the arc c, g, b, and such
that at half the arc g, the elevation g, f, is half the total elevation e, h.
At the end of the arc b, and at any other point in the arc c, b, the
elevation will for all practical purposes bear a similar proportion to the
greatest elevation. ca P, is the lever by which this circular inclined
plane, eccentric or cam, is brought into action; a, being the axis or
fulcrum of said lever; and a, P, may be at any convenient angle with
u, c, or a e. Another example of the lastly above-mentioned principle
of construction is exhibited at Figure 2, and is as follows:-Let b, c,
be an arc of any number of degrees (say 60°); bisect the angle b, a, c,
by a, d, or draw a, d, at any desired angle with ba; produce c, a, to e,
and make ce, equal the elevation to be given to the "sear;" then
produce a, d, to f, (no matter where a, d, may cut the arc 6 c,) and
make d, n, any desired portion of ce. Then by Euclid, 4th Book,
Proposition 5, find o, from which, at distance o, h, o, n, or o, e; describe
the arc b, n, e. According to this principle of construction, it will
appear manifest that as the curved inclined plane c, f, e, at Figure 1,
or b, fe, at Figure 2, is brought into action by the lever a, P, so as to
raise the "sear" of the lock with which it is to be placed in contact,
the power of the trigger at any point of its range of action will always
be the same, as the loss of power consequent upon any variation of
position or shortening of the lever or trigger will be compensated for
by the curved inclined plane. At Figure 3, A A, marks the trigger

page_text: plate; B, a boss formed thereon, in which a screwed hole is made to
receive the screw C, which connects' said trigger plate to the stock of
the gun. DD, are projections formed upon the plate A, and at each side
of the slot through which the trigger E, passes, the same being connected
to the parts DD, by a pin or rivet a, which is the axis upon which the
said trigger turns or moves. G, is a steel spring, one end of which is
fixed upon the boss B, in any convenient manner; and the other and
opposite end takes under the projecting part b, of the trigger, as shewn
at Figures 2, and 3; at which Figures, marks that part of the curved
inclined plane upon which the "sear" of the lock rests when the trigger
is out of action; and d, marks that part of the curved inclined plane upon
which the "sear" would be at the moment of discharge, as exhibited at
Figure 2, which shows the spring g, depressed for the purpose of return-
ing the trigger to its original position upon the pressure being removed
from the finger plate P. And as an additional security and effectual pre-
ventive against the accidental discharge of the contents of fire-arms,
I propose forming the trigger with a step, into which the sear arm falls,
as at a, Figures 2, and 3, for rendering the trigger ineffective at half
cock. At Figure 6, the modified form of construction of the trigger,
as there exhibited, consists in inverting the inclined plane d, and
employing a lever of the second order for imparting motion thereto;
and I propose applying this form of construction of trigger to those
fire-arms in which the "sear" of the lock is quite close to the lower
part of the butt, adjoining the guard, and which would not allow room for
an axis underneath the same. a, is the axis or fulcrum of the trigger;
b, c, a curved slit or opening, in which the sear moves; the line or
distance from a, to b, being formed shorter than from c, to a, and the
curved slot being formed upon a similar principle to that herein-before
mentioned and referred to, it will appear evident that upon motion
being imparted to the trigger in the direction denoted by the arrow's
flight, that the sear would be raised in its passage from c, to b, and
thereby effect the object desired.
Having now described the nature of my said Invention, and in what
manner the same is to be and may be performed, I declare my Inven-
tion of improvements in fire-arms to consist in constructing the triggers

page_text: of
gun locks generally, in the manner and upon the principle herein-
before particularly described, set forth, and represented by the illustra-
tive drawing hereunto annexed, and for the purposes set forth.
In witness whereof, I, the said Philip Harris, have hereunto set
my hand and seal, this Nineteenth day of October, in the year
of our Lord One thousand eight hundred and fifty-three.
Witness, W B. LANGFORD,
PHIL. HARRIS, (L.S.)
Major, Royal Marines, Chatham.
1st L' R.M.