Improvements in Cartridge Cases.
Year: 1892

page_text: Date of Application, 2nd Dec., 1892
Complete Specification Left, 18th Sept., 1893-Accepted, 28th Oct., 1893
PROVISIONAL SPECIFICATION.
Improvements in Cartridge Cases.
1, GEORGE HOOKHAM, of Nos. 7 and 8 New Bartholomew Street, in the City
of Birmingham, Manufacturer, do hereby declare the nature of this invention to be
as follows:-
My invention relates to an improvement which is more especially applicable to
the larger cartridge cases. In such cases it is found that upon firing in the larger
guns, that part of the head which is opposite the fuse aperture or recess in the
breech of the gun is forced out by the explosion and the exterior surface of the
head is thus made higher at the middle. If the case be used to fire a second time
the amount of forcing out is less than that produced the first time.
I find that if the head be sufficiently forced out at that point, that is, at the circle
equal or nearly equal in diameter to the recess in the breech of the gun, then turned
off to a flush exterior, the subsequent pressure brought to bear by the firing has
little or no effect in producing further displacement.
.
My invention consists in forcing out the centre part of the cartridge case head
from the interior of the case by mechanical means, and preferably I trim off the
exterior surface level.
By this simple operation the metal at the centre is put in a suitable state of strain
to resist distortion on firing.
I sometimes isolate the said centre part by turning a groove or grooves in the
head.
Dated this 1st day of December 1892.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Cartridge Cases.
I, GEORGE HOOKHAM, of Nos. 7 and 8 New Bartholomew Street, in the City
of Birmingham, Manufacturer, 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 an improvement which is more especially applicable to
the larger cartridge cases. In such cases it is found that upon firing in the larger
guns, that part of the head which is opposite the fuse aperture or recess in the
breech of the gun is forced out by the explosion, and the exterior surface of the
head is thus made higher at the middle. If the case be used to fire a second time
the amount of forcing out is less than that produced the first time.
I find that if the head be sufficiently forced out at that point, that is, at the circle
equal or nearly equal in diameter to the recess in the breech of the gun, then turned
off to a flush exterior, the subsequent pressure brought to bear by the firing has
little or no effect in producing further displacement.
My invention consists in forcing out the centre part of the cartridge case head
from the interior of the case by mechanical means, and preferably I trim off the
exterior surface level.
By this simple operation the metal at the centre is put in a suitable state of strain
to resist distortion on firing.

page_text: head.
I sometimes isolate the said centre part by turning a groove or grooves in the
Referring to the two accompanying sheets of drawings :-
:-
Figure 1 is a section of the head and end portion of a cartridge case showing the
head in position with its central part opposing the fuse aperture or recess in the
breech of the gun.
Figure 2 is a section illustrating one application of my invention of forcing out
the centre part.
Figure 3 is a section illustrating another application of my invention of forcing
out the centre part.
Figure 4 is a section corresponding to Figure 3 but showing the exterior surface
of the head turned off flush.
Figure 5 is a section showing the operation of a punch F having the final
configuration desired as the finished internal shape of the head.
Figure 6 is a section of a case with the head turned off flush and the interior
shaped by the punch shown in Figure 5.
That part of the metal of the cartridge case head which is marked C (Figure 1)
opposes the fuse recess or aperture B and is liable to be forced out to some extent
by the explosion in the gun as herein before stated. To prevent or minimise the
effect of the explosion by one modification, I form the interior of the head with a
projection as shown in dotted lines at D Figure 2 and I force in this projection to
the position shown in full lines. This forces out a projection E (Figure 2) from
the general shape of the head.
.
Sometimes I cut the groove A A before forcing out.
After forcing out the portion E I turn the exterior surface flush finishing it as
shown in Figure 1.
Sometime I dispense with the projection D from the interior of the surface of
the head and force from the interior producing a recess D Figure 3 in the interior
and a projecting part E on the exterior. This projecting part E is then turned off
flush leaving the exterior surface flat as shown at Figure 4.
The fuse hole is then drilled in the head and the head is finished in any usual
manner.
The forcing out operation is preferably performed by a punch acted on by
hydraulic pressure, the said punch being arranged to force out the metal at C and
opposed by a die having a recess as at B. The punch, however, may be actuated
by a hammer if desired.
Instead of forcing in a local projection as shown at Figure 2 or a local recess as
shown at Figure 3, I may form my punch F Figure 5 of the configuration desired
as the internal shape of the head and by the previous processes I leave the surface D
shown in dotted lines Figure 5 a little higher than its intended final position, which
final position is indicated by the full line beneath. I then place the head on a flat
surface in which is formed the recess B and 1 force down the punch F to the
bottom of the case thus finishing the interior of the head and forcing out the pro-
jection E. This projection E I turn off and leave the finished head as shown at
Figure 5.
.
By my invention the metal at the central part C of the head is strained in such
manner before firing as to prevent any considerable displacement or distortion due
to firing.
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 cartridge cases, preventing or minimising distortion or displacement of the
metal of the head caused by firing by mechanically forcing out or straining that
portion of the head liable to distortion or displacement so as to strain the metal
during manufacture in the same direction as the metal is subsequently acted:on.by.

page_text: the explosion, substantially as and for the purposes hereinbefore described reference
being had to the accompanying drawings.
Dated this 16th day of September 1893.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicant.