IMPROVEMENTS IN THE CONSTRUCTION OF BREECH-LOADING GUNS
Year: 1881

page_text: PROVISIONAL SPECIFICATION left by Francis Macdonald Robertson and
John Joyce at the Office of the Commissioners of Patents on the 10th August
1881.
FRANCIS MACDONALD ROBERTSON, of Croydon, in the County of Surrey, and
JOHN JOYCE, of Edmonton, in the County of Middlesex. "IMPROVEMENTS IN
THE CONSTRUCTION OF BREECH-LOADING GUNS."
This Invention relates to improvements in the construction of the locking,
extracting, and breech mechanism of breech-loading guns, and of a snap action for
securing the back strap or "fore end" of the gun to the barrel, such improvements
being specially applicable to hammerless guns used for sporting purposes.
That part of our said Invention which refers to improvements in the construction
of the breech and locking mechanism is as follows:-At the back of the "action
block," and, by preference, formed in one piece therewith, are arranged the upper
and lower horns for attachment to the stock, as will be well understood. A bearing
is arranged between and has its ends connected respectively to the said horns, and
within an aperture in the said bearing is arranged the striker bar, which may be
cylindrical in form; the forward end of the said striker bar passes through a
suitable hole formed in the action block to the face of the latter, as will be well
understood. On that part of the striker bar which is situated between the inside
of the action block and the before mentioned bearing is formed a shoulder, against
which bears one end of a spiral spring arranged on the striker bar, the opposite end
of such spring acting against the said bearing. In that end of the striker bar
which projects beyond the back of the said bearing is formed a notch, cut
transversely, into which engages one end of the scear which is pivoted at or about
the centre to the said bearing, in such a position that the upper end of the trigger
acts upon the opposite end of the said scear. Within the action block between
the horns, and beneath the hole through which the striker bar passes, is arranged
the bolt for locking the barrel in its closed position, and on the inner end of the
said bolt is formed a fork-like projection which passes at each side of the striker
bar; on the lower side of the said locking bolt is formed a number of teeth, into
which gears a series of teeth, hereinafter referred to as the quadrant, formed on an
extension of the front end of the trigger guard; this latter is hinged or pivoted at
a poiut a short distance from the said toothed end. That part of the locking bolt

page_text: which enters a recess in the lump or projection formed below the end of the
barrel, for the purpose of securing the same, is bevelled in order to allow the
barrel to close with a snap action. When it is desired to unlock the barrel the
free end of the trigger guard is moved down, and as the latter turns on its pivot
or hinge the quadrant will act on the teeth of the locking bolt, and cause the same
to be moved backward until it is entirely disengaged from the end of the barrel;
during the said movement of the trigger guard the fork on the locking bolt will
come into contact with the shoulder on the striker bar, forcing the same back
against the action of the spring, which is thereby compressed, until the end of the
scear engages into the before mentioned notch in the striker bar, thus cocking the
gun, when by a slight continuation of the movement of the trigger guard the
locking bolt will be entirely withdrawn from the barrel, which is then free to drop.
A spring suitably arranged is employed in connection with the scear in order to
keep the same engaged with the notch as above described. On the barrel being
lifted up the bolt will snap into the hole in the projection on the same, the trigger
guard being returned to its normal position.
When it is desired to provide the gun with a "safety bolt," the same is con-
structed and arranged as follows:-A lever is pivoted or hinged by one end to
the before mentioned bearing supporting the striker bar, and to the opposite end of
the said lever is pivoted or hinged a pin or stud which is caused by means of a
spring to project through a suitable aperture, so arranged that the said pin can be
pressed down in the action of firing; on the said lever is a tooth or projection
which engages, when the gun is cocked, with a notch formed in the striker bar,
thus preventing the accidental discharge of the gun by the pulling of the trigger
without the simultaneous pressing down of the said pin or stud.
In some cases, instead of actuating the locking bolt, as hereinbefore described, by
means of the trigger guard, this latter can be fixed and the teeth formed on the
end of a separate lever suitably arranged, as will be well understood, and in some
cases we dispense with the teeth altogether, and arrange the end of the trigger
guard or separate lever to work in a groove or recess formed in the locking bolt.
Another part of our Invention relates to an improved cartridge extractor which
is formed by preference of hardened steel, and is constructed and arranged as
follows: The front end of the said extractor works within the projection under
the end of the barrel, and is made hollow in order to serve as a bush for the front
end of the locking bolt; from the back of the extractor extends a bar or rod
which comes into contact with one arm of a bell crank lever pivoted in suitable
bearings behind the joint or axis on which the barrel oscillates or turns. The
other arm of the said bell-crank lever, when the barrel is turned, comes into
contact with a pin or suitable projection attached to the action block, and causes
the first mentioned arm of the lever to move and push the extractor from its
normal position on the fall of the barrel.
The "fore end" of the gun is secured to the barrel by the following means:-
A slot is formed in the metal fore end, and beneath the said slot is arranged a
sliding bolt having a corresponding slot through which is passed a guide screw, one
end of the said bolt is turned outwards, and has a guide pin attached thereto or
formed thereon, which works through a suitable bearing fixed to the fore-end.
Around the said guide pin is a spiral spring which forces the sliding bolt against a
fixed stud arranged at the opposite end; when in this position one end of the slot
in the said bolt will project slightly beyond the corresponding end of the slot in
the fore end. To the underside of the barrel is attached a hooked stud, which is
passed through the slot in the fore end until the before mentioned projecting end
of the slot in the sliding bolt snaps into the hook in the stud.
In double barrel guns the whole of the mechanism is constructed and arranged
in substantially the same manner as hereinbefore described, but many of the parts
are duplicated, for instance, it will be necessary to employ two striker bars, scears,
triggers, a double extractor and mechanism connected with these parts, such as
the springs, but one projecting pin and lever arranged as above described for.

page_text: effecting the safety locking will be found sufficient. We also construct the
projection on the end of the locking bolt with a double fork so as to embrace both
striker bars.
Our Invention further relates to an improved construction and arrangement of
the striker bar and hole through which the same passes, for allowing the escape of
gas and preventing the same from entering the action chamber. This portion of
our Invention is applicable to other forms of hammerless guns. We effect this
object by mounting on the front end of the striker a washer, piston, or valve of
india rubber, leather, or other suitable material, so that when the detonator has
been struck the said washer, piston, or valve will either by fitting closely or by
coming into contact with a projection formed in the hole in the action block
through which the striker passes, close all communication through the said hole
from the outside to the inside. In order to prevent the excessive pressure of the
gas from effecting a passage through the said hole, we drill a small channel or
channels, in such a position that they open into the front portion of the said hole,
and thus allow the gas to pass freely into the atmosphere. Instead of arranging
the washer, piston, or valve on the striker, as above described, we, in some cases,
arrange it within a recess or enlargement in the hole, the striker being suitably
turned or fitted to act against or through the same.