IMPROVE- MENTS. IN ORDNANCE AND PROJECTILES
Year: 1864

page_text: PROVISIONAL SPECIFICATION left by Perceval Moses Parsons at the
Office of the Commissioners of Patents, with his Petition, on the 18th
May 1864.
I, PERCEVAL MOSES PARSONS, of Blackheath, in the County of Kent, Civil
Engineer, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS. IN ORDNANCE AND PROJECTILES," to be as follows:-
In the construction of ordnance I form the tubes and hoops used in con-
structing built-up or compound guns, by coiling and welding bars of wrought
iron or suitable steel rolled with tongues and grooves to fit into one another
when the bar is coiled round the mandrel; or when the tube is made out of
a single bar or ingot of steel or wrought iron, in addition to hammering or
rolling the same I twist it so as to give the fibres a spiral in place of a
longitudinal direction.
:
In order to impart axial rotation to the projectile without weakening the
gun by cutting grooves in it, I employ ribs or flanges having the requisite
spiral raised above the surface of the bore instead of grooves sunk below it,.
and to enable spherical shot as well as elongated projectiles to be discharged
from guns thus made, I employ two raised ribs or flanges opposite each other,
having their loading and driving sides of the same form. When cylindrical
or cylindro-conoidal projectiles alone are to be used, I employ any convenient
number of raised ribs or flanges, the form in cross section of the driving side
of which is either a straight or curved line inclined to the surface of the bore;
if curved, I prefer making it the arc of a circle struck from a point on a

page_text: straight line drawn through the centre of the bore at right angles to a straight
line drawn from that centre to any point on the rib or flange; the loading side
may either be similar to the driving side or of any other suitable form. For
the purpose of causing the projectile to bear against the driving side of the
rifling ribs or flanges when rammed home, so that it may start without a jar,
I thicken the loading side of the rifling ribs or flanges at the breech end
about the amount allowed for clearance or windage in the grooves of the
projectile.
For the purpose of loading at the breech I employ a moveable conical
breech screw,
and support it on a suitable swinging or hinged frame in which
it can turn freely, and by the aid of which it can be moved in and out of its
place. In order to make the joint at the breech of breech-loading ordnance
gas-tight I employ a gas check or valve made in the form of a ring, with an
annular recess or recesses on its exterior, so that its exterior surface in contact
with its seat will be of less area than its interior surface exposed to the action
of the powder gases; and when the gas check is intended to operate by being
forced back against the breech piece by the pressure of the powder gases, the
area of its surface in contact with the breech piece is made less than the area
of its opposite end. In some cases I employ two split rings, one within the
other, with the splits arranged to break joint.
In the construction of projectiles to enable them to be used with guns rifled
with raised ribs or flanges, I form the projectile when spherical with an
annular groove or grooved belt on its exterior, and when cylindrical or
cylindro-conoidal with spiral grooves cut in it of corresponding form in section
to the rifling ribs, but as much wider as necessary, to allow for windage or
clearance.