An Improvement in Breech Plugs for Ordnance.
Year: 1895

page_text: Date of Application, 20th Apr., 1895
Complete Specification Left, 17th Jan., 1896-Accepted, 22nd Feb., 1896
PROVISIONAL SPECIFICATION.
An Improvement in Breech Plugs for Ordnance.
I, DOUGLAS VICKERS, a Managing Director of Vickers Sons & Company
Limited, River Don Works, Sheffield, in the County of York, Steel
Manufacturers etc. do hereby declare the nature of this invention to be as
follows:-
My invention relates to the construction of the breech and breech plug of a gun
in such a manner that the parts of the screw thread that are cut away in order to
release the plug on a partial turn are considerably less than in plugs as they are
usually made, and consequently that the plug may be considerably shortened with
equal extent of thread engaged. For this purpose, I divide the periphery of the
plug, for the sake of symmetry, into two parts with intervals cut away between
the parts, each of these two intervals being a comparatively small arc of the
circumference.
The two parts which are not cut away, are arcs having their periphery not
concentric with the axis of the plug but of spiral or approximately spiral curvature
each having its one extreme of a less radius than its other extreme. The interior of
the breech being shaped to correspond, the plug on being turned through a part of a
revolution corresponding to each of the cut away parts, is released, the spiral
outline allowing all parts of the thread to clear.
Dated this 20th day of April 1895.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
An Improvement in Breech Plugs for Ordnance.
I, DOUGLAS VICKERS, & Managing Director of Vickers Sons & Company
Limited, River Don Works, Sheffield in the County of York, Steel
Manufacturers etc. 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 :-
My invention relates to the construction of the breech and the breech plug of a.
gun in such a manner that the parts of the screw thread that are cut away, in
order to release the plug on a partial turn, are very much less than in plugs as
they are usually made, and consequently that the plug may be considerably
shortened with equal extent of thread engaged.
In some cases instead of making screw threads on the plug I make divided
collars similar to a thread in section.
I shall describe my invention referring to the accompanying drawings.
Fig. 1 is a transverse section of the breech and the plug, the plug being in its.
locked position.
Fig. 2 is a sectional plan on the line 1-1 of Fig. 1.
Fig. 3 is a transverse section of the breech and the plug, the plug being in its
unlocked position.

page_text: I divide the periphery of the plug A, for the sake of symmetry, into two
parts C and C with intervals DD cut away between the parts C and C, each
of those two intervals being a comparatively small are of the circumference.
The two parts C and C are arcs having their periphery not concentric with the
axis of the plug A but of spiral or approximately spiral curvature, each part
having its one extreme of a less radius than its other extreme. The interior of
the breech B is shaped to correspond with the exterior of the plug A.
The plug A on being turned through a part of a revolution corresponding to
each of the cut away parts D and D, is released from the threads or rings of the
breech B, the spiral outline of the plug A allowing all parts of its thread to clear
the threads of the breech B.
The plug A is mounted as usual on a carrier arm or ring hinged to a pivot at
the side of the gun.
When it is parallel as shewn it would have to be slid rectilineally to the rear
after the partial turn which unlocks it before it could be swung out of the breech,
but the plug may be so tapered that, immediately after the partial turn for
unlocking, it can be swung out.
Having now particularly described and ascertained the nature of this inveu-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The construction of the breech and breech plug for a gun, the plug, which is
either parallel or tapered, having its periphery divided into two or more parts of
screw threads or collars, with small intervals between the portions of threads or
collars, which have their periphery arcs of spiral or approximately spiral
curvature, each are having its one extreme of a less radius than its other extreme,
substantially as described.
Dated this 17th day of January 1896.
ABEL & IMRAY,
Agents for the Applicant.