A NEW OR IMPROVED AUTOMATIC ORTURATOR APPLICABLE TO BREECH LOADING ORDNANCE
Year: 1882

page_text: LETTERS PATENT to Lorentz Albert Groth, K.G.V. Civil Engineer and
proprictor of the Scandinavian Patent Office under the firm of L. A. Groth
& Co 30 Finsbury Pavement London E.C. for an invention of "A NEW
OR IMPROVED AUTOMATIC ORTURATOR APPLICABLE TO BREECH LOADING
ORDNANCE." -A communication from abroad by Louis Freyre, of Sevilla, in
the Kingdom of Spain.
PROVISIONAL SPECIFICATION left by the said Lorentz Albert Groth at
the Office of tho Commissioners of Patents on the 17th April 1882.
LORENTZ ALBERT GROTH, K.G.V. Civil Engineer and Proprietor of the
Scandinavian Patent Office under the firm of L. A. Groth & Co. 30 Finsbury
Pavement London E.C. "A NEW OR IMPROVED AUTOMATIC OBTURATOR
APPLICABLE TO BREECH LOADING ORDNANCE" A communication from abroad by
Louis Freyre, of Sevilla in the Kingdom of Spain
The continual increase of the load of cannons with the view of imparting greater
initial velocity to their projectiles and consequently increasing their range accuracy
and force produces higher pressure of the powder gases notwithstanding the
study which has been devoted to the manufacture and the placing in this piece of
material.
To this circumstance may probably be attributed that the obturation problem
in breech loading pieces has not progressed a single step in the way of satisfactory
solution,
Since its origin two systems of obturation which may be called the principal
systems have been adapted by all nations, varying somewhat in their minor details
of design
The first consists in a metallic ring of copper or steel upon which the gases act
direct, the back surface of which rests against a plate either of copper or steel
The said ring expands with facility on account of its form and moreover receives
directly the force of the gases. But when the force which these gases give out,
exceeds that which had been calculated upon the ring suffers a permanent

page_text: expansion having paid the limit of its elasticity, on the other hand the expansion
of the ring is not equal in all its parts; while its edge reaches a maximum of
expansion, the thicker part expands but very little; so that in this system the
obturation is confined exclusively to the edge, the part which becomes quite useless
through the effect of a feeble blow; as also through the slightest movement the
gases will begin to escapo.
Although supposing the most perfect obturation is obtained at the edge of the
ring, it still remains imperfect between the back surface of the ring & the front
part of the plato which is very frequently very ineffective.
The second system consists in a cylinder open at one end and closed at the other
so that it forms a ring and a plate like the former system but in one solid piece.
The expansion of this obturator is also produced by the direct pressure of the gases
against it and consequently is subject to the same inconvenience as the former
system, there is no fear of defective obturation between the back surface of the
ring and the front part of the plate but the lateral obturation is effected with
difficulty because the shape of this obturator does not facilitate its expanding and
as perfect obturation depends upon expansion it becomes necessary to make the
edges of the obturator thinner, which exposes it to the same difficulties indicated
above, that is to say expansion beyond the limit of elasticity, and if to avoid this
difficulty the edge is made thicker it will not expand and therefor obturation will
not take place
It is therefore diflicult to conciliato these extremes and the more so when applied
to cannons of heavy calibre.
In both of the above named systems the operation is very troublesome: the
obturator requires cleaning and oiling very frequently and constant inspection,
to determine if there is an escape of gas so na to correct it before it becomes
impossible to do so. It becomes hard fitting and difficult to put in its place or
take out, requiring at times the employment of a hammer to start it and when on
account of becoming dirty there is an accumulation of residue of burnt powder, it
requires great effort to take it out. The consequence is that it becomes damaged
and the escape uf gus is the result, thus rendering the piece useless at the most
critical moment.
The Obturator which is the subject of the present invention embodies two
notable features which distinguish it essentially from all other known systems.
1st hint the pressure of the gases does not operate directly upon the obturating
ring, but upon a circular wedge in the shape of a truncated core which cause the
obturating ing to expand
2nd That the expanding movement of the said ring, as well as the force which
ncts to expand it are limited at will
To these two properties another must be added which is peculiar to it and which
is not found in any other obturator viz, that all points of the generator of the
obturating ring produces obturation because in expanding the said generator moves
parallel to itself
In this obturator the degree of expansion which the ring has to undergo is
determined beforehand as well as the pressure which it has to suffer no matter
what may be the forces which the gases generate, and taking caro that it shall be
within the limit of elasticity of the material it will operate perfectly and with
safety and permanent expansion will not occur either on the ring or on that part
of the piece where it rests
This obturator has the following advantages
1st It can be constructed of any class of suitable material without necessitating
any especial condition further than possessing great elasticity. Excellent results
have been obtained by employing in its construction steel from the manufactory's
of Krupp Creusot and Seraing as well as by employing compressed brass.
2nd The operation is easy and rapid because the ring is not expanded beyond
the limit of elasticity by the force of the gases and returns to the same position
that it occupied before the explosion

page_text: 3rd In inanufacturing it special workmen are not absolutely required because
close adjustment is not necessary to secure perfect action.
4th There results from its use a great economy, for it is now required to fire
five times to prove the ordinary obturators whereas in this system one shot only is
required for if the result of one shot is satisfactory there is no reason to doubt but
what it will continue to be so.
5th It will last as long as the piece to which it is applied because the expansion
is not permanent and it is not exposed to blows nor liable to drop on account of
all the parts forming a connected apparatus, moreover as all the points of the
generator are so many points of obturation the apparatus will continue to work
although may have become some-what damaged
6th It is very easy to replace it, and it has the advantage of being able to be
fitted with new rings without the necessity of having the Guu in order to do so.
All these advantages have been shown in actual trials made with cannon of
different calibre with this apparatus applied In some of the trials more than 400
shots have been fired in series of 20, 40 and upwards to 100 shots of rapid firing
without cleansing or oiling, leaving the apparatus intact, always obturating in a
satisfactory manner and without any impediment.
DESCRIPTION OF THE OBTURATOR.
The obturator is composed of a solid piece of steel, or other suitable material ono
end of which forms a truncated core, the middle a cylinder, and the other end a
cylinder of smaller diameter, the extremity of which is screwed to receive a nut.
A steel ring is fitted to the truncated coro portion which is held in place by
means of a nut screwed upon the end of the said piece which presses against the
breech plug, this pressure is graduated by means of the aforesaid nut which is held
fast by means of a screw so that it does not change position at the moment of
discharging
It may be seen from this that the back part of the ring is in contact with the
end of the plug but this end of the plug is not in contact with the small end of the
aforesaid truncated core but separated from it a small distance by means of a
strong spiral spring located within the said plug.
When the explosion takes place the gases acting directly on the surface, force
back the truncated cofe until it reaches the end of the breech plug, in doing so the
obturator ring is expanded uniformly until every point of every generator of the
said ring is pressed against the bore of the gun and hermetical obturation takes
place through its entire surface.
After the shot the spiral spring which had been compressed by the force of the
explosion expands again taking back to its original position the piece so that the
ring is allowed to contract to its original position also.
As the play of the piece is limited the force brought to bear upon the'ring must
always be the same no matter whether the charge be light or heavy and it is
plain to be seen that the degree of expansion of the said ring may be nicely
graduated by means of the nut.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Lorentz Albert Groth in the Great Seal Patent Office on the
17th October 1882.
LORENTZ ALBERT GROTH K.G.V. Civil Engineer and Proprietor of the
Scandinavian Patent Office under the firm of L. A. Groth & Co 30 Finsbury
Pavement London E.C. A NEW Onl IMPROVED AUTOMATIC OBTURATOR
A communication from abroad by
"
APPLICABLE TO BREECH LOADING ORDNANCE"
Louis Freyre of Sevilla in the Kingdom of Spain.
The continual increase of the lond of cannon with a view of imparting greater
initial velocity to the projectiles and consequently increasing their range accuracy
and force produces higher pressure of the powder gases notwithstanding the study
which has been devoted to the manufacture and the placing in this piece of
inaterial. To this circumstance may probably be attributed that the obturation
problem in breech loading pieces has not progressed a single step in the way of
satisfactory solution. Since its origin two systems of obturation which may be
called the principle systems have been adopted by all nations varying somewhat
in their minor details of design.
The first consists of a metalic ring of copper or steel upon which the gases act
direct the back surface of which rests against a plate either of copper or steel.
The said ring expands with facility on account of its form and moreover receives
directly the force of the gases But when the force which these gases give out
exceeds that which had been calculated upon the ring suffers a permanent expansion
having passed the limits of its elasticity
On the other hand the expansion of the ring is not equal in all its parts while
its edge reaches its maximum of expansion the thicker parts expands but little
so that in this system the obturation is confined exclusively to the edge, the part
which becomes quite useless through the effect of a feeble blow as also through
the slightest movement the gases will begin to escape.
Although supposing the most perfect obturation is obtained at the edge of the
ring it still remains imperfect, between the back surface of the ring and the front
part of the plate which is very frequently very ineffective
The second system consists in a cylinder open at one end and closed at the
other so that it forms a ring and a plate like the former system but in one
solid piece.
The expansion of this obturator is also produced by the direct pressure of the
gases against it and consequently is subject to the same inconveniences as the
former system.
In this obturator there is no fear of defective obturation between the back
surface of the ring and the front part of the plate but the lateral obturation is
effected with difficulty because the shape of this obturator does not facilitato its
expanding and as perfect obturation depends upon expanding it becomes necessary
to make the edges of the obturnior thinner which exposes it to the same difliculties
indicated above that is to say expansion beyond the limit of elasticity and if to
avoid this difliculty the edge is made thicker it will not expand and therefore
obturation will not tako place. It is therefore difficult to conciliate these extromes
and the more so when applied to cannon of large calibre.
In both of these systems the operation is very troublesome the obturator
requires cleaning and oiling very frequently and constant inspection to determino
if there is an escape of gas so as to correct it before it becomes impossible
to do so.

page_text: It becomes hard fitting and difficult to put in its place or take out requiring
at times the employment of a hammer to start it and when on account of becoming
dirty there is an accumulation of residues of burnt powder it requires great effort
to take it out. The consequence is that it becomes damaged and the escape of
gas is the result thus rendering the piece useless in the most critical moment.
The obturator which is the subject of the present invention embodies two
notable features which distinguish it essentially from all other known systems.
They are
1st That the pressure of the gases does not operate directly upon the obturating
ring but upon a circular wedge in the shape of a truncated cone which causes the
obturating ring to expand
2nd That the expansive movement of the said ring as well as the force which
acts to expand it are limited at will.
To these two properties another one must be added which is peculiar to it and
which is not found in any other obturator viz That all points of the generatrix
of the obturating ring produce obturation because in expanding the said generatrix
moves parallel to itself.
In this obturator the degree of expansion which the ring has to undergo is
determined beforehand as well as the pressure which it has to suffer no matter
what may be the force which the gases generate and taking care that it shall be
within the limit of clasticity of the material it will operate perfectly and with
safety and permanent expansion will not occur either on the ring or on that part
of of the piece where it vents
This obturator has the following advantages,
1st It can be constructed of any suitable material without necessitating any
special conditions further than possessing great clasticity. Excellent results have
been obtained by employing in its construction steel from the manufactory of
Krupp Creusot and Seraing as well as by employing compressed brass.
2nd The operation of the piece is easy and rapid because the ring is not
expanded beyond the limit of elasticity by the force of the gases and returns
to the same position that it occupied before the explosion.
3rd In manufacturing it special workmen are not absolutely required because
close adjustment is not required to secure its perfect action.
4th There results froin their use a great economy because it is now required
to fire five times to prove them whereas in this system one shot is required for
if the result of one shot is satisfactory there is no reason why it should not
continuo to be so.
5th It will last as long as the piece to which it is applied because the expansion
is not permanent and is not exposed to blows nor liable to drop on account of all
the parts forming a connected apparatus, morcover as all the points of the generatrix
are so many points of obturation the apparatus will continue to work although it
may have become somewhat damaged.
6th It is very easy to replace it and it has the advantage of being able to fit
pieces with new rings without the necessity of having the gun in order to do so
All these advantages have been shown in actual trials made with cannon of
different calibre with this apparatus applied. In some of them more than 400
trial shots have been made in series of 20. 40 and up to 100 shots of rapid firing
without either cleaning or oiling leaving the apparatus intact obturating always
in a satisfactory manner and without any impediment
The obturator is composed of a solid piece of steel a, b, c, d, e, f one end of
which forms a truncated cone, the middle a cylinder and the other end a cylinder
of smaller diameter the extremity of which is screwed to receive a nut
A Steel ring G. H. M. N. is fitted to the truncated cone portion which is held
in place by means of the nut R. S. X. T screwed upon the end of the said piece
a, b, c, d, e, f, which presses against the breech plug this pressure is graduated by
means of a nut R. S. X T which is held fast by means of the screw K so that it
does not change position in the moment of discharging
.

page_text: It will be seen from this that the back part of the ring is in contact with the
end of the plug but this end of the plug is not in contact with the small end of
the aforesaid truncated cono but separated from it a small distanco by means of
strong spiral spring O located within the said plug
When the explosion takes place the gases acting directly on the surface a b force
back the truncated cono till it reaches the end of the breech plug in doing so the
obturator ring g. h. m n is expanded uniformly until every point of every generatrix
of the said ring is pressed against the bore of the gun and obturation takes place
hermetically and through its entire surface.
After the shot the spiral spring O which had been compressed by the force
of the explosion expands again taking back to its original position the pieco
a. b. c d e f so that the ring g. h. mn is allowed to contract to its original
position
As the plug of the picco a. b. c d. e. f is limited the force brought to hear upon
the ring y. h. m. n. must always be the same no matter whether the charge be
light or heavy and it is plainly seen that the degree of expansion of the said ring
may be nicoly graduated by means of the nut R. S. X. T.
Having now described the nature of the said Invention and the manner in
which the same is to or may be carried into effect I would havo it understood that
what I claim is.
1st The obturator a. b. c d. c. f composed of a solid piece of steel one end forming a
truncated cone or core the middle a cylinder and the other end a smaller
cylinder on the extremity of which is screwed a nut held fast by a screw.
2nd The peculiar form of the obturating ring which enables all points of the
generatrix to obturate.
3rd The strong spiral spring O round the smaller end of the obturator to check its
recoil and which forces it back after each explosion
4th The nut R. S. T. X. and screw K by means of which the recoil of the obturator
is regulated
5th The combination of the above described parts constructed applied and operating
as herein beforo described and illustrated in the drawings
In witness whereof I the said Lorentz Albert Groth have hereunto set my
hand and seal this fourteenth day of July-in the year of our Lord one
thousand eight hundred and eighty two.
LODRAZIVLJ
ZDRA ATAKIZ