Improvement in Drop-down Guns.
Year: 1893

page_text: Date of Application, 3rd Nov., 1893
Complete Specification Left, 2nd Aug., 1894-Accepted, 15th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvement in Drop-down Guns.
I, JOHN ROBERTSON, of 73 St. James Street, Pall Mall, in the County of
Middlesex, Gunmaker, do hereby declare the nature of this invention to be as
follows:-
This invention relates to means whereby both barrels of a double-barrel gun can
be fired by the action of a single trigger, and either barrel fired at will, the two
barrels being fired either alternately or one barrel any desired number of times in
succession, the fired barrel having of course to be recharged after each discharge.
The arrangement permits of great rapidity in firing, and has the further advantage
that by the use of a single trigger there is much less liability to injure the firing
finger than when two triggers are used, when it often happens that such finger is
hurt against the rear of the guard when pulling the forward trigger, or between the
two triggers in firing the rear trigger.
In carrying out my invention, upon the trigger I pivot an arm which can be
shifted so that when the trigger is pulled it acts upon the sear of the hammer on
the side to which it has been shifted, and so releases same and fires the barrel on
that side. This shifting of the pivotted arm from one side to the other is effected
automatically by the action of firing, whereby when one barrel is fired such arm is
moved to the position to fire the other barrel, so that by this means the two barrels
will be fired alternately, but means are also provided for shifting the lever from one
side to the other by hand (by means of a lever fitted to the pivot of the arm outside
the stock) so that when desired the same barrel may be discharged any number of
times in succession by simply shifting the arm back to its original position after
each firing.
The pivotted arm is acted upon by a spring which tends to throw it to one side
or the other of its central position, and such arm is provided with a ledge or shoulder
on each side which when the arm is on one side and the trigger is operated lifts the
sear and so fires the barrel on that side. The arm is also provided with an inclined
surface on each side, which acts against a correspondingly inclined surface on the
sear, and as the latter is maintained in its raised position after firing until the
hammer of the barrel on this side is again cocked, while the trigger, when
released from pressure, under the action of a spring is forced forward to the
position for firing again, thereby carrying the pivotted arm with it, the incline
on the latter acting against the incline on the sear throws the arm over to the
position to engage the other sear when the trigger is again operated. The
successive pulls on the trigger will thus cause the two barrels to be fired
alternately, but as each sear is maintained in its raised position after firing,
this action will be interfered with after both barrels have been discharged, and
in order to overcome this the lump on the hammers which keeps the sears raised
after firing, is on one side constructed so as to liberate the sear and permit its
descent slightly in advance of the sear on the other side, so that the sear on the
latter side which remains raised for a short period will throw the arm over to
the opposite side as the trigger is moved forward to the firing position under
the action of its spring. Either the left or the right hand sear may be arranged
to be released first, and according to which of these it is, so either the left or

page_text: right barrel will be discharged the next time the trigger is pulled, unless the
pivotted arm on the trigger is shifted to the opposite side by means of the external
lever before firing.
Dated this 3rd day of November 1893.
ALLISON BROS.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvement in Drop-down Guns.
I, JOHN ROBERTSON, of 73 St. James Street, Pall Mall, in the County of
Middlesex, Gunmaker, 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 :-
This invention relates to means whereby both barrels of a double-barrel gun can
be fired by the action of a single trigger, and either barrel fired at will, the two
barrels being fired either alternately or one barrel any desired number of times in
succession, the fired barrel having of course to be recharged after each discharge.
The arrangement permits of great rapidity in firing, and has the further advantage
that by the use of a single trigger there is much less liability to injure the firing
finger than when two triggers are used, when it often happens that such finger is
hurt against the rear of the guard when pulling the forward trigger, or between
the two triggers in firing the rear trigger.
The method of carrying out my invention is illustrated in the acccompanying
drawings, in which :-
Fig. 1 is a longitudinal section through the lock mechanism.
Fig. 2 a sectional plan view of same.
Fig. 3 a transverse section showing the parts in one position.
Fig. 4 a corresponding section showing the parts in another position.
Fig. 5 a similar section showing the parts in a third position.
Fig. 6 a side elevation of the trigger and the pivoted arm or part for actuating
the sears.
Fig. 7 a plan view of Fig. 6.
Fig. 8 an end view of the pivoted arm or part for actuating the sears, and of the
lever for shifting same by hand, and
Fig. 9 a plan view of such lever.
In carrying out my invention, upon the trigger A I pivot an arm B, which can
be shifted so that when the trigger is pulled it acts upon the sear C or C' of the
hammer D or D' on the side to which it has been shifted, and so releases same and
fires the barrel on that side. This shifting of the pivoted arm B from one side to
the other is effected automatically by the action of firing, whereby when one barrel
is fired such arm is moved to the position to fire the other barrel, so that by this
means the two barrels will be fired alternately, but means are also provided for
shifting the arm from one side to the other by hand (by means of a lever E pivoted
outside the stock), so that when desired the same barrel may be discharged any
number of times in succession by simply shifting the arm back to its original
position after each firing.
The pivoted arm B is acted upon by a spring F which tends to throw it to one
side or the other of its central position, and such arm is provided with a ledge or
shoulder b, b, on each side, which when the arm B is on one side and the trigger A
is operated lifts the sear C or C¹, and so fires the barrel on that side. The arm B
is also provided with an inclined surface 62, 63, on each side, which acts against a
correspondingly inclined surface c, c', on the sears C, C', respectively, and as each
of the latter is maintained in its raised position after firing until the hammer D, D',
of the barrel on this side is again cocked, while the trigger A, when released from

page_text: pressure, under the action of a spring a is forced forward to the position for firing
again, thereby carrying the pivoted arm B with it, the incline 62 or 63 on the latter
acting against the corresponding incline on the sear, throws the arm B over to the
position to engage the other sear when the trigger A is again operated. The
successive pulls on the trigger will thus cause the two barrels to be fired alternately,
but as each sear is maintained in its raised position after firing, this action will be
interfered with after both barrels have been discharged, and in order to overcome
this the lump d, on the hammers, which keeps the sears raised after firing, is on one
side constructed so as to liberate the sear and permit its descent slightly in advance
of the sear on the other side, so that the sear on the latter side, which remains
raised for a short period will throw the arm B over to the opposite side as the
trigger A is moved forward to the firing position under the action of its spring a.
Either the left or the right hand sear may be arranged to be released first, and
according to which of these it is, so either the left or right hand barrel will be
discharged the next time the trigger is pulled, unless the pivoted arm B on the
trigger is shifted to the opposite side by means of the external lever E before
firing.
Supposing the parts to be in the position shown in Figs. 1, 2 and 3, the pulling
of the trigger A will by reason of the shoulder of pivoted arm B, carried by
such trigger, engaging the sear C of the right hand barrel, raise the latter and
so release the hammer D, which will consequently descend under the action of
its spring, and fire such right hand barrel. When the trigger A is released its
spring a will move same forward again to the firing position, carrying the
pivoted arm B with it, while the sear C remains in its raised position. The
inclined surface 6 of arm B will thus act against the correspondingly inclined
surface c of sear C, and such arm be consequently thrown over to the opposite
side, as shown in Fig. 5, so that upon trigger A being again pulled the left hand
barrel will then be discharged.
If in first firing the pivoted arm B is in the position shown in Fig. 5, the first
pull of the trigger A would cause the left hand barrel to be discharged, and
upon the release of the trigger the arm B would be thrown over to the position
shown in Figs. 1, 2 and 3, so that the next pull would effect the discharge of
the right hand barrel.
The pivoted lever E has a forked end e which engages an upward extension b*
of the pivoted arm B, so that by turning such lever E to one side or the other
the pivoted arm B can be shifted by hand to the position necessary to fire either
barrel first as desired. The lever E acts in conjunction with letters "R" and "L'
("right" and "left"), on the stock so as to indicate the position of the pivoted
arm B.
"
After both barrels have been discharged the action of opening the gun to reload
same will, by reason of the difference in size of the lump d, on the respective
hammers, which keep the sears raised, cause one of such hammers to be cocked
slightly in advance of the other, and the sear of such hammer to at once descend,
so that the trigger A will then move forward and the pivoted arm B it carries will
consequently be thrown over to the opposite side to the position to engage the sear
of the hammer first cocked before the second hammer is cocked, and therefore the
barrel which it is desired to discharge first will be so discharged the next time the
trigger is pulled. It will be readily understood that the arrangement may be such
that either the right or left hand barrel will be discharged first.
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. In double barrel guns the employment of a pivoted arm mounted on a single
trigger and acting in conjunction with suitable surfaces formed on both sears, for
the purpose of throwing such pivoted arm alternately to the positions necessary for
releasing the hammers of the right and left hand barrels, substantially as specified.

page_text: 2. The combination with the arrangement specified in the preceding claim, of a
pivoted lever engaging the pivoted arm carried by the single trigger which serves
to fire the right and left hand barrels alternately, and which pivoted lever may be
actuated by hand so as to shift the pivoted arm to the necessary position to fire
either the right or the left hand barrel as desired, substantially as described.
Dated this 12th day of June 1894.
ALLISON BROS.,
Agents for the Applicant.