U.S. patent application number 11/908958 was filed with the patent office on 2008-12-25 for lead-free expansion projectile and manufacturing process.
Invention is credited to Laudemiro Martini Filho.
Application Number | 20080314280 11/908958 |
Document ID | / |
Family ID | 36991217 |
Filed Date | 2008-12-25 |
United States Patent
Application |
20080314280 |
Kind Code |
A1 |
Martini Filho; Laudemiro |
December 25, 2008 |
Lead-Free Expansion Projectile and Manufacturing Process
Abstract
The projectile of the present invention combines the advantages
of both the solid and hollow point designs, featuring the initial
ballistics of a solid projectile and the terminal (target)
ballistic effects of a hollow-point projectile, without the risk of
collecting undesired foreign matter into the cavity in the unfired
configuration and also eliminating the possible feeding problems
from the magazine to the barrel chamber by a simple manufacturing
process. A plunger (4) is initially positioned in the expansion
chamber (2) of the projectile. Upon sinking into the projectile
body (1) no part of the plunger head (5) touches the internal
surface of the expansion chamber (2) except for the bottom of such
chamber (2) so that the plunger (4) has no active role in the
expansion of the projectile upon impact.
Inventors: |
Martini Filho; Laudemiro;
(Guapituba-Ribeirao Pires, BR) |
Correspondence
Address: |
CARSTENS & CAHOON, LLP
P O BOX 802334
DALLAS
TX
75380
US
|
Family ID: |
36991217 |
Appl. No.: |
11/908958 |
Filed: |
March 17, 2005 |
PCT Filed: |
March 17, 2005 |
PCT NO: |
PCT/BR2005/000035 |
371 Date: |
November 21, 2007 |
Current U.S.
Class: |
102/510 ;
86/54 |
Current CPC
Class: |
F42B 12/34 20130101 |
Class at
Publication: |
102/510 ;
86/54 |
International
Class: |
F42B 12/34 20060101
F42B012/34 |
Claims
1. An expansion projectile for firearms, comprising: (a) a first
piece having a deformable, cylindrical projectile body (1) with a
front part tapering towards a front end, a set of regularly spaced
slits placed at the front end of the projectile and an internal
cavity opened towards said front end, composed of an expansion
chamber (2) connected to a cylindrical haft extension (3) and (b) a
second piece having a plunger (4) with the general shape of a nail
with a head (5) and a shank (6), with all elements featuring radial
symmetry around the longitudinal axis of the projectile, wherein
the plunger (4) is initially positioned so that the external face
of the head (5) lies exposed at the very front tip of the
projectile and the shank (6) lies inserted into the expansion
chamber (2), wherein upon sinking into the projectile body (1), no
part of the plunger (4) head (5) touches the internal surface of
the expansion chamber (2) except for the bottom of said chamber at
the end of the course of the sinking movement.
2. An expansion projectile for firearms, according to claim 1,
wherein the full axial length of the plunger (4) is such that, in
the unfired configuration, a length preferably between 5 and 25% of
the plunger total extension lies inserted into the forward portion
of the shaft (3).
3. An expansion projectile for firearms, according to claim 1, in
which the external shape of the head (5) of the plunger (4) is such
that the projectile presents an uninterrupted aerodynamic profile
in its unfired configuration which is preserved after firing until
the moment of impact, characterized by the fact that the
cross-section of the shank (6) of the plunger (4) is preferably
that of a regular polyhedron with 3 to 8 sides, featuring axial
symmetry regarding the longitudinal axis of the projectile, with
contact between the pieces occurring at the tips of the polyhedral
figure, thus leaving a certain amount of free section between the
hank (6) and the cylindrical shaft (3).
4. An expansion projectile for firearms, according to claim 2,
wherein the external shape of the head (5) of the plunger (4) is
such that the projectile presents an uninterrupted aerodynamic
profile in its unfired configuration which is preserved after
firing until the moment of impact, characterized by the fact that
the cross-section of the shank (6) of the plunger (4) is preferably
that of a regular polyhedron with 3 to 8 sides, featuring axial
symmetry regarding the longitudinal axis of the projectile, with
contact between the pieces occurring at the tips of the polyhedral
figure, thus leaving a certain amount of free section between the
hank (6) and the cylindrical shaft (3).
5. An expansion projectile for firearms, according to claim 1,
wherein the projectile presents a cavity opened towards the front
end after the plunger (4) sinks into the projectile upon impact,
characterized by the fact that the maximum cross section radius of
the shank (6) is slightly bigger than the nominal cross-section
radius of the cylindrical shaft (3), with the penetration of the
shank (6) into the shaft (3) being allowed by deformation of the
material of the plunger (4) under the force of the projectile
impact.
6. An expansion projectile for firearms, according to claim 1,
wherein there are no regularly spaced slits placed at the front end
of the projectile.
7. An expansion projectile for firearms, according to claim 1,
wherein the mass of the plunger (4) is no more than 5% of the total
mass of the projectile in its unfired configuration.
8. A manufacturing process for the projectile according to claim 1,
comprising: (a) forming of the cylindrical shaft extension (3)
placed right behind the expansion chamber (2) and continuously
connected to it; (b) calibrating against a perfectly symmetrical
model.
Description
BACKGROUND OF THE INVENTION
[0001] It is well known that projectiles, especially those used in
police work and personal defense, must feature a high capability
for stopping an attacker at once, without traversing the target and
thus risking injuring innocent people. That is particularly
important when the use of said ammunition is considered under
extreme situations, such as that involving life risk for the police
officer, an innocent pedestrian, etc.
[0002] Therefore projectiles used in police operations must be able
to pass through tactical obstacles that offer protection to the
criminal, such as vehicle doors and windscreen. However, the same
projectile must do so without altering its original trajectory,
lest there is serious risk of injury to bystanders that were not
the intended target of police action.
[0003] Another fundamental aspect of projectile performance is that
it must not fragment upon hitting any target. This restriction is
related to the already addressed risk of projectile fragments
injuring innocent people or damaging property which was not the
original target of police action, especially in public spaces of
urban environment.
DESCRIPTION OF RELATED ART
[0004] A recent, updated example of hollow-point projectile design
can be found on PCT/BR04/000006, "LEAD-FREE MONOBLOC EXPANSION
PROJECTILE AND MANUFACTURING PROCESS" filed by the same Applicant,
which describes a solid monobloc projectile with a cavity on the
longitudinal axis which is opened towards the fore end of the
projectile. Said hollow-point projectile, which features a
plurality of regularly spaced grooves distributed over the external
front face, opens up upon hitting a soft target, creating a
flower-shaped element which is much more effective in transferring
energy to the target than are standard solid profile projectiles.
This higher energy transfer fosters a higher stopping power, and
the cavity design also tends to avoid fragmentation of the
projectile upon hitting both hard and soft targets.
[0005] Nevertheless, the idea of a hollow-pointed projectile
features some inconveniences. First of all, there is the
aerodynamic inconvenience of placing an open cavity at the front
end of the projectile, which entails ballistic problems such as
trajectory instability generated by the pattern of the air vortex
created ahead of the projectile.
[0006] Another ballistic inconvenience of the hollow-pointed
profile is the loss of energy through attrition, which reduces the
amount of energy actually transferred to the target upon
hitting.
[0007] The feeding mechanism from the magazine to the barrel
chamber also tends to yield a higher percent of jams when handling
hollow-pointed ammunition than would be the case with
regular-shaped, standard ammunition.
[0008] The storage and loading of the ammunition raises issues for
hollow-pointed projectiles, which could collect dust and other
external particles in the open cavity, possibly compromising the
performance of the ammunition when fired.
[0009] There is also a more subtle, subjective and yet important
political factor affecting the manufacturing and usage of
hollow-point projectiles, which have been much maligned over the
years by its labeling as cruel and, to some extent, it's former
association with the intentional use of contaminants in the
projectile and fragmentation that would add to its lethal
power.
[0010] Another example of the state of the art can be found in
PCT/EP01/01868 "REDUCED CONTAMINANT DEFORMABLE BULLET, PREFERABLY
FOR SMALL ARMS", in the name of Knapworst et al. This patent
addresses the inconveniences of an exposed hollow-point projectile
by covering the open end of the projectile's cavity with a plastic
element with the general shape of a nail. The nail head lies
exposed at the very tip of the projectile, and preserves the
regular external shape of the projectile right up to the impact
moment, and then acts as a pusher to split, the cavity wall open.
The patent names this plastic, nail-shaped element a plunger. The
movement of said plastic plunger from the very tip of the
projectile towards the rear of the projectile is oriented by the
previous alignment and partial insertion of the plunger shank with
a purpose-designed axial shaft that receives the plunger shank when
the shank moves rearwards upon hitting the target, the plunger
sinking into the rear body of the projectile.
[0011] Among the fundamental design features of the Knapworst
patent projectile are the use of the plastic plunger conical head
to force the projectile wall open upon impact (there are no
external slits to foster the opening of the projectile wall into a
flower shape) and the precise machining of the shapes of both the
plunger shank and the corresponding projectile shaft that receives
it upon impact.
[0012] Knapworst's patent, design, although solving many of the
already addressed inconveniences of open-cavity projectiles,
presents some inconveniences of its own. The precision of machining
and use of annealing become critical for the performance of the
projectile, because the slightest geometrical or dimensional
imperfection might cause problems such as irregular expansion of
the cavity, breakage of the plunger, etc. Therefore, production
costs are higher in view of the requirement of a comparatively
strict manufacturing process control.
[0013] The lack of external slits keeps the projectile wall from
tearing itself into various pieces, and in fact the fired
projectiles show preserved continuity of the wall perimeter, with
little radial expansion if compared to the flower-shaped pattern
obtained with the use of external slits. Less expansion allows for
less energy transmission and thus less stopping power.
[0014] The use of a cylindrical shape for both the plunger shank
and its receiving axial shaft is not conductive to the exhaustion
of the volume of air that fills the projectile shaft of the unfired
ammunition. Upon impact, the plunger's round cross-section blocks
the shaft completely, leaving no gap for the air to escape. That
raises a pneumatic resistance, which could compromise the
symmetrical expansion and general performance of the
projectile.
[0015] The chamfering of a section of the circular cross-section of
the plunger shaft is supposed to alleviate the problem, but the
fact that the exhaust area is small and its geometric disposition
is not axially symmetrical suggest the need of a better solution
for the exhaust of the shaft air.
SUMMARY OF THE INVENTION
[0016] The projectile of the present invention combines the
advantages of both the solid and hollow point designs, featuring
the initial ballistics of a solid projectile and the terminal
(target) ballistic effects of a hollow-point projectile, without
the risk of collecting undesired foreign matter into the cavity in
the unfired configuration and also eliminating the possible feeding
problems from the magazine to the barrel chamber. That is achieved
with comparably simple manufacturing process control, with major
reduction of precision requirements at no risk to the performance
of the projectile.
[0017] One object of the present invention is to disclose a
projectile that easily and quickly deforms upon expansion when
penetrating soft targets.
[0018] Another object of the present invention is to ensure the
proper sinking of the plunger into the projectile body, so that
after the initial impact the cavity in the front face of the
projectile is completely exposed and brings about the desired
terminal (target) ballistic effects.
[0019] Another object of the present invention is to avoid any sort
of fragmentation of the projectile, so as to avoid unintended
damage to targets other than the one intentionally fired upon.
[0020] All of the objects disclosed above are to be achieved
without increasing too much the manufacturing costs of the
projectile, so as to keep the final price of the product in the
reach of most police forces around the world.
[0021] The present invention can be better understood by analyzing
the specification text along with the attached set of Figures, in
which:
[0022] FIG. 1 is a side view illustrating the general external
shape of an unfired projectile according to the present invention,
with slits (a) and in the alternative configuration without slits
(b);
[0023] FIG. 2 is a longitudinal cross-section view illustrating an
unfired projectile according to the present invention;
[0024] FIG. 3 is a longitudinal cross-section view illustrating a
projectile according to the present invention in its fired
configuration, after it has hit the target, with slits (a) and in
the alternative configuration without slits (b);
[0025] FIG. 4 is a perspective view illustrating a projectile
according to the present invention in its fired configuration,
after it has hit the target, with slits (a) and in the alternative
configuration without slits (b);
[0026] FIG. 5 is a longitudinal cross-section view illustrating an
unfired projectile according to the state of the art;
[0027] FIG. 6 is a longitudinal cross-section view illustrating a
projectile according to the state of the art in its fired
configuration, after it has hit the target;
[0028] FIG. 7 is a perspective view illustrating a projectile
according to the state of the art in its fired configuration, after
it has hit the target.
[0029] The present invention eliminates the inconveniences found in
the state of the art by the use of a specific configuration that,
comprises two pieces:
[0030] a deformable, cylindrical projectile body (1) with a front
part tapering towards the front end. This cylindrical projectile
features an internal cavity opened towards the front end, being
said cavity composed of an expansion chamber (2) and a cylindrical
shaft extension (3) which is continuously connected with it and is
positioned right behind, both cavities featuring radial symmetry
regarding the longitudinal axis of the projectile, being the shape
of said expansion chamber preferably identical to that described in
PCT/BR04/000006, "LEAD-FREE MONOBLOC EXPANSION PROJECTILE AND
MANUFACTURING PROCESS" filed by the same Applicant, and
[0031] a plunger (4) with the general shape of a nail, with a head
(5) and a shank (6), also featuring radial symmetry regarding the
longitudinal axis of the projectile.
[0032] The full axial length of the shank (6) of the plunger (4) is
such that, in the unfired configuration, a length preferably
between 5 and 25% of the shank's total extension lies inserted into
the forward portion of the shaft (3). That keeps the plunger (4)
firmly in place in the unfired configuration and serves the purpose
of initial orientation of the sinking movement upon impact.
[0033] The external shape of the head (5) of the plunger (4) is
such that the projectile presents in its unfired configuration an
uninterrupted aerodynamic profile that is preserved after firing
until the moment of impact. The cross-section of the shank (6) of
the plunger (4) is preferably that of a regular polyhedron with 3
to 8 sides, with contact between the elements occurring at the tips
of the polyhedral figure, thus leaving a certain amount of free
section between the shank (6) and the cylindrical shaft (3). This
is important to facilitate the exhaustion of the air trapped inside
the cylindrical shaft (3) and suddenly pressurized by the sinking
of the shank (6) into it upon impact.
[0034] The maximum cross section radius of the shank (6) is
slightly bigger than the nominal cross-section radius of the
cylindrical shaft (3), with the penetration of the shank (6) into
the shalt (3) being allowed by deformation of the plastic material
of the plunger (4) under the force of the projectile impact. This
serves the purpose of hindering the separation between the
projectile body (1) and the plunger (4) after impact, achieving a
press-fit between them.
[0035] As stated before, one of the objects of the present
invention is to disclose a projectile that easily and quickly
deforms upon expansion when penetrating soft targets. That is
preferably achieved by following the same cavity design guidelines
described in PCT/BR04/000006, "LEAD-FREE MONOBLOC EXPANSION
PROJECTILE AND MANUFACTURING PROCESS" filed by the same Applicant,
including the preferential use of external slits around the open
face of the specially designed cavity to foster the forming of a
flower-shape element after impact. Alternatively, it is possible to
produce the projectile of the present invention without the
external slits, but then the expansion after impact is reduced and
so is the energy transfer, consequently reducing the stopping power
of the projectile.
[0036] The ideal design is such that the energy transfer to the
targeted body should be performed by the whole projectile. In the
event of accidental separation between the projectile body (1) and
the plunger (4), part of the energy will inevitably end up
transferred to the plunger, in a direct proportion to its mass.
Therefore it is advisable to make the plunger (4) mass much smaller
that that of the projectile body (1), so that in the event of an
accidental separation, the smallest possible amount of energy is
transferred to the "stray" plunger (4). In the present invention,
the mass of the plunger (4) is no more than 5% of the total mass of
the projectile in its unfired configuration.
[0037] The reliance on the apparently fragile flower-shape pattern
of the projectile to transfer energy to the target might suggest
fragmentation is an issue. There might be some misgivings regarding
the possibility of one of the "petals" of the hollow-point
projectile coming of (such as by tearing) and thus separating from
the bulk of the projectile inside the target, which would amount to
fragmentation. Nevertheless, there is in fact a proportion between
the amount of energy imparted to the projectile upon firing (which
is the superior limit of the energy of the projectile upon hitting
the target), the mechanical resistance of the projectile material
and the maximum extent of the "tearing" of the "petals" in the
projectile at the very end of its deformation. Those skilled in the
art will realize that a simple series of tests will indicate, for
each caliber and type of ammunition, the ideal number, depth and
length of the projectile slits in order to obtain the desired
"flower-shaped" pattern and yet avoid any risk of fragmentation due
to excessive "flowering".
[0038] In the present invention, the sequence of events from firing
to final disposition of the projectile is as follows: The
projectile is fired, follows its external ballistic path and
eventually hits its target. Upon impact, the plunger (4) is forced
inside by the pressure of the target against the external surface
of the plunger head (5), which drives the whole plunger (4) towards
the rear part of the projectile body (1). When the plunger (4)
sinks into the projectile body (1), it leaves behind and thus
exposes the expansion chamber (2), which is penetrated and filled
up by target material. It is important to observe that the force
that actually expands the expansion chamber (2) is the one caused
by penetration of target material into it. In the configuration
that features external slits, these provoke the splitting of the
front-end perimeter of the projectile body (1) during expansion and
generate the flower-shape element associated with optimal energy
transfer. In the alternative configuration without the external
slits, the expansion chamber (2) expands without breaking the
circular perimeter of the projectile body (j) front end.
[0039] Another important aspect of the present invention is that
upon sinking into the projectile body (1), no part of the plunger
(4) head (5) touches the internal surface of the expansion chamber
(2) except for the bottom of said chamber at the end of the course
of the sinking movement, so that the plunger (4) has no active role
in the expansion of the projectile upon impact.
[0040] The projectile body (1) material is preferably from the
copper class or a copper alloy.
[0041] The material of the plunger (4) is preferably polyamide or
polyethylene. This plastic material is resistant to breakage and
yet somewhat flexible in view of the forces applied to the plunger
(4). Alternatively, metallic powder can be added in the casting of
the plunger (4) in order to make it magnetically traceable into the
target after firing.
[0042] Manufacturing Process
[0043] The manufacturing process includes the following sequence
that is generally similar to the sequence described in
PCT/BR04/000006, "LEAD-FREE MONOBLOC EXPANSION PROJECTILE AND
MANUFACTURING PROCESS" filed by the same Applicant:
[0044] obtaining a cylinder of soft material preferably from the
copper class or copper alloy, by cutting a wire;
[0045] forming the cavity in one or more operations, by cold
forming, being the cylindrical shaft (3) formed in the same
operation of cold forming with the expansion chamber (2) or
alternatively in a separate operation of cold forming, or
alternatively by drilling. The cylindrical shaft (3) is placed
right behind the expansion chamber (2) and is continuously
connected to it;
[0046] forming the forward part of the piece obtained, in a die,
also forming the slits (if required for the ammunition being
manufactured) in the same operation, and
[0047] annealing, polishing and cleaning the formed projectile.
[0048] All these operations are well known by those skilled in the
art of ammunition manufacture.
[0049] There is a last step added to the manufacturing process of
the projectile according to the present invention, and that is a
final calibration step. The basic approach of the manufacturing
process according to the present invention eliminates the need for
strict, repetitive and costly manufacturing process controls.
Nevertheless, the possibility of major geometric and/or dimensional
inconsistencies must be accounted for, and that is the reason for
including this final calibration step. All manufactured projectiles
are checked against a perfectly symmetrical model, and in case the
calibration step detects geometric or dimensional inconsistencies,
the specific unit is automatically resized so as to conform to the
manufacturing standards. That ensures, among other aspects, that no
part of the plunger (4) head (5) touches the internal surface of
the expansion chamber (2) when the plunger (4) sinks into the
projectile body (1). Said calibration step helps prevent undesired
developments such as breakage of the plunger (4) upon impact, which
is also aided by the fact that the plastic used to manufacture the
plunger (4) is resistant to breakage and yet somewhat flexible in
view of the forces applied to it.
INDUSTRIAL APPLICABILITY
[0050] The manufacturing process of the projectile of the present
invention is a clear indication of the invention's industrial
applicability. Those skilled in the art will realize that the
description of one or more preferential incorporations of the
present invention does not limit its scope of application, which is
in fact limited only by the claims attached herein.
* * * * *