Improvement in Drop-down Guns.
Year: 1894

page_text: Date of Application, 21st Mar., 1894
Complete Specification Left, 21st Jan., 1895-Accepted, 20th Apr.. 1:95
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, 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 that 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.
According to one method of carrying out my invention, behind the trigger
which I employ, and which is shaped so as to be capable of acting on the sear of
both hammers, I arrange a tumbler or part, which can (when desired) be operated
from the outside, and the action of which is that when in one position it throws a
hinged or pivotted part of one sear over such trigger in the position to be acted
upon and so release the hammer it governs, while in the other position it throws
the corresponding part of the sear governing the other hammer into such position.
When the hammer of one trigger moves forward to fire its barrel, a detent or
projection thereon depresses the forward end of the sear, thus raising the opposite
end of same and bringing the pivotted part thereof in contact with a cam surface
on a post or pillar, so that the hinged part is forced back, and, by contact with the
tumbler described, turns same on its pivot and brings it to the other position, in
which it is retained by action of a spring. The sear in question has thus been
shifted clear of the trigger so that it will not be operated the next time the latter
is pulled, but the turning of the tumbler has brought the hinged part of the other
sear into such a position that when the trigger is released from pressure and
thrown forward by a spring acting on same, it will be forced by the tumbler over
the trigger to the position for being acted upon by the next pull of the trigger, so
that the other barrel will then be discharged. The operation of the sear and
"tumbler on each side is identical, so that if not otherwise specially desired the
action of the trigger will be to fire the two barrels alternately, but when it is
specially desired to fire a given barrel and the parts are not then in the requisite
position for so doing, it will only be necessary to move the tumbler over from one
position to the other by a lever on the outside of the stock, thereby moving the
hinged part of the sear on one side from over the trigger and at same time forcing
the hinged part of the other sear over it, and by doing this after each discharge
it will be seen that the same barrel may be fired any desired number of times in
succession.
"
The spring acting upon the trigger moves same forward after each discharge, by
simply removing the pressure on the trigger.
According to a modified arrangement I cause the trigger to act directly on the
sear of one barrel so as to release same in the usual manner, and in the action of
pulling the trigger for this purpose, such trigger shifts the tumbler so as to bring
777

page_text: it into position for acting on the sear of the other barrel when the trigger is again
pulled. If however the gun is again charged without firing the second barrel, a
sliding bar or bolt actuated by the action of opening the gun shifts the tumbler
back to its original position, so that when the trigger is again pulled the same or
first barrel will be again discharged. The sliding bar referred to is preferably
actuated by the lever which controls the locking bolt, so that when same is turned
to enable the barrels to drop for reloading it will shift the tumbler in the manner
described.
Dated this 21st day of March 1894.
ALLISON BROS.,
Agents for the Applicant.
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-barreled gun
can be fired by the action of a single trigger, 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
when firing the rear trigger.
According to one method of carrying out my invention, behind the trigger
which I employ, and which is shaped so as to be capable of acting on the sear of
both hammers, I arrange a circularly reciprocating tumbler, which can (when
desired) be operated from the outside, and the action of which is that when in one
position it throws a hinged or pivotted part of one sear over such trigger in
the position to be acted upon and so release the hammer it governs, while in the
other position it throws the corresponding part of the sear governing the other
hammer into such position. When the hammer of one trigger moves forward to
fire its barrel, a detent or projection thereon depresses the forward end of the sear,
thus raising the opposite end of same and bringing the pivotted part thereof in
contact with a cam surface on a post or pillar, so that the hinged part is forced back,
and, by contact with the tumbler described, turns same on its pivot and brings it
to the other position, in which it is retained by action of a spring. The sear in
question has thus been shifted clear of the trigger so that it will not be operated
the next time the latter is pulled, but the turning of the tumbler has brought the
hinged part of the other sear into such a position that when the trigger is released
from pressure and thrown forward by a spring acting on same, it will be forced by
the tumbler over the trigger to the position for being acted upon by the next pull
of the trigger, so that the other barrel will then be discharged. The operation of
the sear and tumbler " on each side is identical, so that if not otherwise specially
desired the action of the trigger will be to fire the two barrels alternately, but
when it is specially desired to fire a given barrel and the parts are not then in the
requisite position for so doing, it will only be necessary to move the tumbler over
from one position to the other by a lever on the outside of the stock, thereby
moving the hinged part of the sear on one side from over the trigger and at same
time forcing the hinged part of the other sear over it, and by doing this after each

page_text: discharge it will be seen that the same barrel may be fired any desired number of
times in succession.
The spring acting upon the trigger moves same forward after each discharge, by
simply removing the pressure on the trigger.
According to a modified arrangement cause the trigger to act directly on the
sear of one barrel so as to release same in the usual manner, and in the action of
pulling the trigger for this purpose, such trigger permits the tumbler to shift so as
to bring it into position for acting on the sear of the other barrel when the trigger
is again pulled. If however the gun is again charged without firing the second
barrel, a sliding bar or bolt actuated by the action of opening the gun shifts the
tumbler back to its original position, so that when the trigger is again pulled the
same or first barrel will be again discharged. The sliding bar referred to is
preferably actuated by the lever which controls the locking bolt, so that when
same is turned to enable the barrels to drop for reloading it will shift the tumbler
in the manner described.
But in order that my invention may be fully understood I will proceed to
describe same by the aid of the accompanying drawings, in which Figs. 1 to 12
inclusive illustrate a suitable method of carrying out the first arrangement,
Figs. 13 to 35 inclusive illustrate two suitable methods of carrying the second
arrangement into effect, and Figs. 36 to 39 illustrate a further modification of such
second arrangement.
Referring to the first arrangement
Fig. 1 is a sectional elevation of same.
Fig. 2 a plan view thereof.
Fig. 3 an end view.
Fig. 4a detail side elevation of the trigger, tumbler and sear.
Fig. 5 a plan view of Fig. 4.
Fig. 6 another detail side elevation similar to Fig. 4, but showing the parts in a
different position.
Fig. 7 a plan view of Fig. 6.
Fig. 8 a side elevation of the sear.
Fig. 9 a plan view of Fig. 8.
Fig. 10 another plan view of Fig. 8, with the pivotted arm or part of the sear in
another position.
Fig. 11 a sectional end view of Fig. 8, and
Fig. 12 a plan view of the external lever for shifting the tumbler from one side
to the other from the outside when desired.
Each of the sears A, A¹, carries a pivotted part or arm B, B', which is acted
upon by a spring C, C', tending to throw it out to the position shown in Fig. 10.
A tumbler D is arranged between the two sears, such tumbler being pivotted and
acted upon by a spring E which tends to throw same and hold it on one side or
other of the centre line.
The trigger F has two arms f,, acting respectively on one or other of the
pivotted arms B, B', carried by the scars A, A1, when the trigger is pulled, thus
raising the sear and so discharging the barrel on that side on which the sear
actuated is situated.
The tumbler D has two vertical arms or projections d, d', one of which is in
contact with the rear of the pivotted arms B or B on the sear on that side to
which the tumbler is thrown over, and when the sear is in bent, and its rear end
consequently lowered, the spring E acting on the tumbler overcomes the spring C
or C, acting on the pivotted arm B, or B', and so brings it over armor f¹ of
trigger F, so that when the latter is pulled the sear of the arm B or B' acted upon
will be raised and the barrel on that side discharged.
The action of raising the sear brings the forward end of the pivotted arm against
an inclined projection or cam surface h, h, on the lock plate H, II', (see Figs. 8
to 11) and this cam surface causes the pivotted arm to turn on its pivot to the
position shown in Fig. 10, against the action of the spring E of tumbler D, the

page_text: Figs. 24 to 26 inclusive are detail views of one method I employ for returning
the tumbler D to its original position by the action of opening the gun for
recharging.
In this arrangement the trigger F when first pulled acts directly on the sear A
on one side, and such sear then remains raised until the hammer on that side is
recocked by the usual movement in opening the gun for recharging.
The tumbler D which must turn on its pivot to enable it to come into position to
be raised by the next pull of the trigger and thus act on the tail end of the other
sear A so as to fire the second barrel, is during the first pull prevented from so
turning by the contact of an arm thereon against the end of the first sear A as
shown in Figs. 16 and 17. But as soon as this latter is raised the tumbler is then
free to turn under the action of its spring E, and this movement brings another
arın d' on the tumbler under the tail end of the second sear A¹, as shown in
Figs. 22 and 23. At the same time a lug or projection on the tumbler enters a
notch 7 of the trigger F, and a lot d in the tumbler comes opposite a pin don
the stil or pivot on which it turns. The tumbler D is thus free to rise vertically
when the trigger F is again pulled, and by contact of its armd with the tail end of
sear A', the latter will be raised and the barrel on this side of the gun consequently
be fired.
Figs. 13, 14, 15, 24, 25, and 26, show one method of shifting tumbler D buck to
its original osition when the gun is opened for recharging, such methol esisting
1
in the employment of a sliding rod K connected at one end with the tail end of
locking bolt L, and its opposite end bearing against one side of the tumbler, so that
when the locking bolt lever M is turned the rod K will move backwards and so
shift the tumbler back to its original position, and as the action of opening the gun
will recock the hammers, and so bring the sears back to their original position, the
arm d will again come in contact with the end of sear A. and thus retain the tumbler
in such position, until the first barrel has been again fired.
This return movement of the tumbler D may be effected in various other methods
than that above described, Figs. 27 to 32 inclusive of the drawings showing two
other of such methods.

page_text: Referring to the arrangement illustrated in Figs. 27, 28 and 29,
Fig. 27 is a sectional side elevation of such arrangement.
Fig. 28 a plan view showing the parts in one position, and
Fig. 29 a plan view showing the parts in another position.
In this arrangement an arm N on the safety bolt O bears against the tumbler D
and forces same back to its original position when the safety bolt is moved to the
position to lock the movement. When the locking bolt lever M is actuated to open
the gun, the sliding rod K bearing against the rear of locking bolt L is forced back
to the position shown in Fig. 29, and as such rod K also bears on the safety bolt O,
the latter will also be forced back and its arm N will consequently return tumbler D
to its original position. The backward movement of the safety bolt O brings it
over the trigger in the usual manner, and so locks the action and prevents any
discharge occurring (although pressure is applied to the trigger) until the bolt O is
first moved forward.
In Figs. 30 to 32 inclusive
Fig. 30 is a sectional elevation of another arrangement for returning the
tumbler D to its original position by the action of opening the gun for
recharging.
Fig. 31 is a plan view of Fig. 30 with the parts in one position, and
Fig. 32 a plan view with the parts in another position.
In this arrangement the spindle P of the locking bolt lever M is formed with a
cam P, and this acts on the sliding rod K which bears against the safety bolt O,
so that when the latter is forced back the arm N it carries bearing against tumbler D
will return same to its original position, as shown in Fig. 32.
Figs. 32, 32, and 32 illustrate a modification of the arrangement shown in
Figs. 13 to 23, as applied to an external hammer gun (although same might be
equally well applied to a hammerless or internal hammer gun), and in which the
circularly reciprocating tumbler D is moved back to the position to ensure the
first barrel being fired again after such barrel has been recharged, by the action of
the hammer when being recocked.
In these figures, Fig. 324 is a sectional elevation of this arrangement.
Fig. 32 a plan view with the parts in position for firing the second barrel, and
Fig. 32 a plan view with the parts in position for firing the first barrel.
The sear A as in the previous arrangement is acted upon directly by the
trigger F so as to disengage same from hammer X and allow same to descend and fire
the first barrel. The lower part of hammer X carries a pin Y engaging a hole in
the forward end of the sliding rod K, the rear end of which bears against the arm d
of the tumbler D and prevents the latter from turning on its pivot under the action
of its spring E. When hammer X descends rod K is moved back, thus permitting
tumbler D to turn on its pivot to the position shown in Fig. 32B, so that its arm
is then under sear A', whereby when trigger F is next pulled (and the tumbler D
consequently raised vertically on its pivot), sear A¹ will then be acted upon, and
the hammer X¹ consequently released, whereby the second barrel will be
discharged.
When hammer X is recocked, pin Y will pull the sliding rod K forward again,
and by the engagement of the rear end of the latter with arm d of tumbler D, such
tumbler will be turned on its pivot back to the position shown in Fig. 32°, when its
arm d will no longer be under sear A', and the next time trigger F is pulled the
first barrel will be again discharged.
Instead of arranging the tumbler D so that same is only raised by the trigger F
after it has shifted to the position for acting upon the second sear, I may cause
such tumbler to be raised on each pull of the trigger, that is to say both when the
trigger is pulled for discharging the first barrel (and consequently before the
tumbler has shifted to the position for engaging the second sear) as well as when
the trigger is pulled for discharging the second barrel.
A suitable arrangement of this kind is shown in Figs. 36 to 39 inclusive of the

page_text: drawings, in which Fig. 36 is a sectional side elevation of such arrangement with
the parts in position for discharging the first barrel.
Fig. 37 a plan view of Fig. 36.
Fig. 38 a sectional end view of Fig. 36.
Fig. 39 is a plan view showing the parts in position for discharging the second
barrel.
As above stated the tumbler D is arranged so that it is free to rise vertically on
its pivot no matter in what position it may be, so that same will be raised with each
pull of the trigger, for which purpose it is in permanent engagement with the
trigger in all positions. In this arrangement the sear A of the first barrel may
rest either directly on the trigger so as to be raised thereby when such trigger is
pulled for discharging the first barrel (in the same manner as in the arrangement
previously described), or, as the tumbler D is raised by each pull of the trigger,
such first sear may he actuated through the tumbler, the latter arrangement heing
shown in Figs. 36 to 39 inclusive.
It will be seen that when the parts are in the position shown in Fig. 37 the
projection or arm d' on the tumbler D is situated beneath the tail end of sear A, a
small projection a thereon preventing the tumbler D turning round on its pivot.
The trigger F being pulled scar A will be released, and as the latter remains in
its raised position, the tumbler D will be free to turn on its pivot as soon as the
pressure on trigger F is relaxed, thus bringing such tumbler into the position shown
in Fig. 39 with its arm or extension d' under the tail end of sear A', so that the
latter will be released (and the second barrel consequently discharged) when
the trigger F is again pulled.
The tumbler D may be returned to its original position by any of the methods
described in connection with the preceding arrangement.
In practice find that the shifting of the tumbler from its original position to the
position necessary for firing the second barrel is liable to occur practically
simultaneously with the firing of the first barrel, and that the second barrel is
consequently fired unintentionally, this effect being due to an involuntary action of
the firing finger due to the recoil from the first discharge, which causes a relaxation
of the pull on the trigger, and then a renewal of such pull after the tumbler has
shifted from one side to the other.
In order to overcome this difficulty I propose to employ an interceptor which
prevents the tumbler acting on the second sear until after the involuntary action
above referred to has occurred, and which further absolutely locks the second sear
so as to render it impossible for same to be actuated, or released by the force of
the recoil itself until after such involuntary action has taken place and the trigger
is again pulled.
This interceptor forms however no part of the present invention and I make no
claim thereto in this Specification, but as the use of same is necessary or advisable
in some of the constructions above described, I will now proceed to describe same
in connection with Figs. 13 to 23 inclusive, and Figs. 33 to 35 inclu-ive, the latter
being detailed views of the particular construction of trigger 1 employ.
I make the trigger in two parts F, F, the part F formed in one with the pull
and being pivotted to part Flat 2, so that the part F can move upwards a certain
distance before the part F1 begins to rise. The part F is acted upon by a spring (
which keeps same normally in its downward position, as shown in Fig. 33. This
part F has an ear or projectiou³ which extends above part F1, when the part F
is in its raised position, as shown in Fig. 35.
The arm d on tumbler D besides bearing against the end of sear A when the
latter is in bent, so as to prevent the tumbler D turning on its pivot as above
described, also acts in conjunction with the two parts F, F, of the trigger, in order
to serve as an interceptor and prevent the full movement of the tumbler until the
desired moment.
The tumbler D has also another arm or extension d*, which serves to lock the

page_text: second sear A¹, until the tumbler has turned to the position to fire the second
barrel.
Referring to Figs. 16 and 17, where the parts are in the position for firing the
barrel controlled by sear A, it will be seen that the intercepting arm d is bearing
against the end of such sear A, so that the tumbler D cannot turn on its pivot,
while the arm or extension d* is right over the tail end of sear A', so that the latter
cannot possibly rise to release the hammer it controls, thus effectually locking such
sear A¹
When the trigger F is pulled the first movement is to raise part F of same to its
full upward extent in relation to part F¹, after which the two parts rise together
until on contact with sear A they raise the latter and so discharge the first barrel.
The rising of sear A has removed the end of same above the arm d of tumbler D,
and the latter at once turns slightly under the action of its spring until arın d
comes in contact with the side of part of the trigger, as shown in Figs. 18 and 19.
In this position the arm or extension d* of tumbler D is still over the end of
sear A', and the latter consequently remains locked. The involuntary action due
to the recoil now occurring the parts F, F, of the trigger now descend to a certain
extent, and arm d consequently clears the top of part F', whereby the tumbler D
can turn slightly further round on its pivot, but the arm d then comes in contact
with the ear or projection f³ on part F, which ear, as the part F is in its raised
position in relation to part F', projects above the top of the latter. The parts are
shown in this position in Figs. 20 and 21, where it will be seen that tumbler D is
still unable to turn sufficiently to bring it to the position for actuating sear A', and
further that such sear still remains locked by the arm dx of such tumbler.
Upon
the pull on trigger F being released however part F at once descends and arm d of
tumbler D then clears the top of the ear or projection f³, when the tumbler
immediately turns to its full extent, thereby unlocking sear A', by removing arın d*
from over the tail of same, and at same time bringing the arm of such tumbler
under such sear A', which will consequently be actuated thereby when the tumbler
is raised in the manner hereinbefore described when the trigger is next pulled. The
last named position of the parts is shown in Figs. 22 and 23.
It will be readily understood that the particular arrangement last described may
be modified indefinitely, the essential feature being that the tumbler or part for
actuating the second sear be provided with an intercepting surface or surfaces acting
in conjunction with a corresponding surface or surfaces (carried by the trigger or
other suitable part of the action), and which will effectually prevent the full move-
ment of such tumbler to the position necessary for enabling the second barrel to be
discharged, until after the involuntary action due to recoil has occurred, and also
preferably at same time locking the sear for effecting such second discharge until
the tumbler has completed its full movement.
Such an arrangement is also shown as applied to the construction illustrated in
Figs. 32, 32B, 32° of the drawings.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
In double barreled single trigger drop-down guns
1. The combination with the single trigger and the two sears of a circularly
reciprocating tumbler which by the action of discharging the first barrel is shifted
so as to bring it into position for acting upon the second sear when the trigger is
again pulled, all substantially as specified.
2. The combination with the single trigger of two sears each provided with a
pivotted arm and of a circularly-reciprocating tumbler for throwing each of such
arms alternately into position for being acted upon by such trigger, and further of
means whereby by the action of discharging one barrel such tumbler is caused to
move so as to act on the pivotted arm of the opposite sear, all substantially as
Specified

page_text: 3. The combination with the single trigger of two sears one of which is acted
upon directly by such trigger, and of a circularly reciprocating tumbler which by
the action of discharging the first barrel is shifted so as to bring it into position for
acting upon the second sear when the trigger is again pulled, all substantially as
specified.
4. The combination with the single trigger of two sears and a circularly
reciprocating tumbler to which a vertical movement is imparted on each pull of the
trigger, substantially as and for the purpose specified.
5. The combination with either of the constructions specified in Claims 3 and 4
of the means for returning the circularly reciprocating tumbler to its original
position by the action of opening the gun for recharging, substantially as
specified.
Dated thin 01st dow of La 1805
ALLISON BROS.,
Agents for the Applicant.