IMPROVEMENTS IN HOLLOW PROJECTILES
Year: 1877

page_text: PROVISIONAL SPECIFICATION left by Peter Jensen at the Office of the
Commissioners of Patents on the 19th December 1877. (A communication
from abroad by Hermann Emil Albert Hellhoff, of Mayence, Germany.)
PETER JENSEN, of Chancery Lane, London. "IMPROVEMENTS IN HOLLOW
PROJECTILES." (A. communication from abroad by Hermann Emil Albert Hellhoff,
of Mayence, Germany.)
In the Specification of a Patent granted to the communicator the 27th December
1876, No. 5000, are described means for enabling nitro-glycerine and analogous
explosive compounds to be used in and with hollow projectiles, these means consists
of the ordnance tube for firing the projectile, and in the projectile itself.
The chief object of this present Invention is so to improve and simplify the
construction of the projectile. These improvements are the result of a great many
actual and successful experiments.
According to the aforesaid former Invention, the projectile consisted of two main
parts, viz., the main body or projectile cylinder, and the propelling cylinder
appliances, which are secured to the rear of the projectile cylinder.
According to this present Invention, propelling cylinders are arranged around or
in one with the main body, thus shortening the length considerably, but increasing
the diameter of the projectile. The propelling cylinders are insulated as regards
heat by means of hair, felt, and wood jacket, and may be more or less in number
and size, according to the power required; a centre of gravity regulating appliance
is not needed because of the shortness of the projectile.
The projectile is in front provided with an ignition chamber with percussion
mantle, and with a domed shield screwed into a ring on the wood jacket or mantle
of the projectile. The wooden ring or disc carrying the percussion cap or capsule
has a metallic ring round its circumference, and can by a screwed pressing ring
be pressed hard down on the charge bag or sack made of canvas, waxed outside.
The number of centering springs in front of the projectile may be increased
because of the increased diameter of the projectile.
The novel arrangement of the propelling cylinders necessitates a secure insulation
as to heat between the mine or cylinder filled with the charge and the ignited

page_text: propelling cylinders. For this purpose the mine is first covered with hairfelt, say,
about, inch or 5/8 inch thick, and then with a wood jacket, say 1 inch or 1'½ inch
thick, and formed with exterior recesses wherein the propelling cylinders are placed;
outside of this is placed another wood jacket formed with interior recesses fitting
over the propelling cylinders. The projectile is at front and rear strengthened by a
deep ring with the aforesaid narrow hoop over; these hoops are the only parts of
the projectile in contact with the interior of the tube or ordnance.
The ignition fuse or rocket tube at the rear of the projectile is let into a wooden
insulator behind the bottom of the cylinder; the fuse has as many branches as there
are propelling cylinders.
The ring fitting over the retarding springs at the rear of the projectile is put on
when inserting the projectile into the ordnance tube, and is left behind therein when
the projectile is shot out.