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Патент USA US2405245

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Aug. 6, 1946.
‘
A. ‘E. USHAKOFF
EXAMINING THE INTERIORS OF GUN BARRELS
- Filed Jan. 5, 1942
2,405,245
Patented Aug. 6, 1946
2,405,245
UNITED STATES PATENT OFFICE
EXAMINING THE INTERIORS 0F GUN I
BARRELS
Alexis E. Ilshakoff, Beverly, Mass, assignor to
United Shoe Machinery Gprpbration, Fleming
1
ton, N. 'J., a ‘corporation of New Jersey
Application January 5, 1942, Serial No. 425,671 '
6 Claims. (Cl. 18--5)
2
This invention relates to examining the bore of
the grooves is liable to affect disadvantageously
the proper rotation of the projectile and/or its
proper velocity, both of which are essential to the
accurate ?ight and maximum striking power of
a 'ri?edgun barrel to learn the presence and na
ture of defects which may be present.
In the manufacture of gun barrels, for example
those of antiaircraft or antitank guns, it is cus
tomary to provide in a suitably shaped barrel of
5 the projectile.
_
The testing device has a generally cylindrical
member I‘! having two radial ports l9 which are
in communication with the longitudinal central
steal a smooth bore and a communicating shell
chamber; and then by a ri‘fling operation to pro
vide in the bore a series of parallel spiral channels
or grooves, such grooves forming the ri?ing and
bore 21, the rear end of which is in communica
tion ‘with a pipe 23 for compressed air from any
suitable source, the ?ow of which is controlled by ‘a
serving to impart rotation to the projectile when
the ?nished gun is ?red. It is very desirable that
three-way valve 25. The forward inturned end of
there should be no defects in the surfaces of the
rifled barrel since such defects are liable to af
a hollow cylinder 2'! of elastic material such ‘as
rubber is clamped tightly by means of a wire man
re'cft adversely the shooting qualities of the gun. 15 annular groove 29 formed in a member [7; and
'The present invention provides a method and a
the rear end 'of the rubber cylinder is clamped
device for use in examining the interior of a gun
barrel to ?nd out whether there are any defects
tightly in two annular grooves 3|, 33 formed in
the same member. There is thus produced an
in its otherwise smooth surface, and if defects are ,
elastic bag which is in?ated when compressed air
present to ‘learn their nature.
20 is admitted to the interior of the bag through the
Referring to the accompanying drawing,
pipe 23. At the forward end of the cylindrical
member I‘! there is adjustably fastenedby a set
Fig. 1‘ is a perspective of a vessel containing a
hot liquid, for example, Water, in which a sheet
screw 35 a collar 31 which has ‘a sliding ?t on the
of ‘thermoplastic material of, proper dimensions
surfaces of the lands l3; and on the rear end
has been immersed to soften it preparatory to 25 of the cylindrical member there is fastened "by a
wrapping the heated sheet around a cylindrical
set screw 39a second collar 4! having a cylindri
holder.
cal portion to ?t the cylindrical portion pf the
“Fig. 2 is a view in longitudinal median section
shell chamber and a tapered portion to ?t vthe ta
of the breech end of a ri?ed gun barrel with the
Dered portion of said chamber. I
device of the present invention in place, the hol
low cylinder of thermoplastic material having
been expended to take an ‘imprint of the interior
of, the gun barrel.
'
A sheet of heated thermoplastic material ‘133
(shown in its ?at condition in Fig. l)v ‘of the
proper size is wrapped about the rubber bagbe
tween the projections or collars 3'! and ‘Ill. The
cylindrical member [7, with the hollow cylinder
of softened thermoplastic material in place, is
_ _
7 Fig. 3 is a cross section on tile line III--III of
Fig. 2'; and
Fig. 4 is a perspective of the hollow‘ cylinder
after it has been removed from the gun barrel so
that its exterior may readily be inspected.
'In the ri?ing of a gun barrel the cuts of the
ri?ing tool begin at a locality near the forward
end of the shell chamber vand continue to the
inserted in the breech end of the gun barrel; com;
pressed air is admitted for a short interval
through the pipe 23; and then ‘the supply of air
is cut off and the pipe exhausted. The hollow
cylinder of thermoplastic material is ?rst ex
panded and then cooled, after which the testing
device is slid with a spiral motion out of the gun
muzzle, any defects in the ri?ing being more likely
to occur during the ?rst part of the travel of the
barrel and the cylinder removed. Its exterior,
tool. For this reason the illustrated device for
which has taken on the imprint of the lands and
detecting the presence and nature of defects in 45 the ri?ing grooves, is then examined. Fig. 4 is a
the surfaces of the bore is of comparatively short
perspective of such a cylinder of thermoplastic
length and is adapted to detect defects only in a
material after it has been removed fork'insp'ection,
small extent at the breech end of the bore. It
there being shown a long scratch which indicates
should be understood, however, that the length
a defect in the bottom of one of the ri'?ing
of the device will depend upon how much of the 50 grooves.
_
bore it is thought necessary or desirable to ex
The ‘time consumed in getting theheated cyl
amine.
v
inder of thermoplastic material into ‘the gun bar
> There is shown in Fig. 2 the rear portion of a
gun ‘barrel 1 having a bore 9 which extends from
the forward tapered portion of the shell chamber
II to the muzzle, not shown. The ri?ed portion
55
rel, expanding it, cooling it and removing it for
inspection should be short. The thermoplastic
material should therefore be a fairly tough one
which is solid at room temperature; it should
of the bore begins a short distance from the for
soften under a moderate degree of heat and
ward end of the shell chamber and consists (Fig.
should remain plastic and self-supporting over a
3) of lands 13 and spiral rifling grooves l‘5. Any
considerable range of temperature. Solid waxes,
slight defect in the surfaces of lands or those of 60 which would otherwise be suitable, are compara
2,405,245
to add toughness and to increase the range of *
plasticity. Below are examples of suitable mate
Example I
_
_ Parts by weight
,
,
43.75
,
V
__
_
_
of its surfaces, said device comprising an elon
gated member having a port which leads to its
periphery, an in?atable bag fastened to the mem
Castor oil __________________ -i ____ ________ 18.75
7
Parts by weight
Ethyl cellulose _________________________ __ 44.00
be withdrawn for inspection.
‘3. A device for taking an impression of the in
10 terior of a gun barrel to determine the condition
Opalwax #10 ____________________ __-_____'_- 37.50
Example II
M
7 hering to the interior of the gun barrel and may
rials.
____; _,
.
a heated, softened hollow cylinder of said ma
terial, and exerting ?uid pressure upon the in
terior of the hollow cylinder to cause its outer
surface to take an imprint of the interior of the
gun barrel including the ri?ing grooves, where
upon the thermoplastic material sets without ad
tively weak and remain plastic for only a short
temperature range. In order to modify these
characteristics such waxes may be combined with
a resinous substance of higher molecular weight
Ethyl cellulose
’.
4,
3
ber and having its interior in communication
15 with the port, spaced projections on the member
constructed and arranged to permit the member
to be slid into theinterior of the gun barrel and
acid _____________ __' ____________ __ 19.5
to prevent movement of the elongated member
radially of said barrel, a hollow member of ther
Example III
'
Parts by weight 20 moplastic material located outside the bag, and
Opalwax #10 ______________ _.' __________ __ 36.5
Stearic
Ethyl cellulose _________________________ __ 50.00
Stearic acid ___________________________ __ 50.00
means for causing a ?uid under pressure to ?ow
through the port to in?ate the bag and thereby
to make an imprint of the interior of the gun
The ethyl cellulose is a product of the Hercules
barrel upon the exterior of the thermoplastic
Powder Company of the type put out by that
company as “B, granular, high viscosity, 100 C. 25 member.
4. A device for taking an impression of the
P.,” and any tough resinous substance of high
ri?ed interior of a gun barrel to determine the
molecular weight which is compatible with the
condition of its surfaces, said device comprising
particular wax chosen may be employed. Opal
an elongated member having a port which leads
wax #10 is a product of the E. I. du Pont de
to its periphery, an in?atable bag fastened to the
Nemours Company. The ingredients are mixed 30 holder
and having its interior in communication
for a. few minutes at room‘ temperature in a
with
the
port, spaced collars adjustably fastened
jacketed mixer, whereupon steam at about 80 ~
to the member constructed and arranged to per
pounds pressure is turned on and the mixing
mit the member to be slid into the interior of the
continued until the ethyl cellulose granules are
gun barrel and to prevent movement of the elon
dissolved and the mass is of the consistency of 35
gated member radially of said barrel, a member
heavy molasses. The mass then cools slightly, is
of thermoplastic sheet material outside the bag
removed from the mixer while still plastic and
and located between the collars, and means for
rolled into sheets from which the small sheets 43
admitting a ?uid under compression into the port
of proper dimensions are out. 1
~
for in?ating the bag and thereby making an im
40
The thermoplastic materials of the examples
pression of the interior of the barrel on the outer
are plastic and self-supporting at 100° 0., remain
surface of the thermoplastic member.
ing so throughout a. considerable range of tem
5. A device for taking an impression of the
perature below 100° C., and-at room temperature
interior of a ri?ed gun barrel having a shell cham
are tough solids. They are‘heated by placing
berin its breech and which is of larger diameter
them in boiling water, are expanded by an air
ratgits rear end than is the ri?ed bore and has at
pressure of about 80 pounds to the square inch,
its forward end a tapered portion, said device
and may be withdrawn approximately one minute
comprising an elongated member having a Port
after they have been expanded. . The sheet 43 of
which leads to its periphery, spaced projections
thermoplastic ' material may conveniently be
50 on said elongated member, the rear projection
heated to soften it by suspending it by means of
having a tapered portion to fit the tapered por
a support 49 in boiling water 45 contained in a
tion of the shell chamber and the forward pro
receptacle 41.
7
Having thus described the invention, what I
claim as new and desire to secure by Letters Pat
ent of the United States is: '
jection being of a diameter to engage the lands
of the ri?ed bore, an in?atable bag located on
55 said elongated member, a hollow member of ther
moplastic material located outside the in?atable
bag, and means for causing a ?uid under pressure
to ?ow through the port to inflatethe bag and
thereby to make an imprint of the interior of the
providing a thermoplastic material, heating'the
gun barrel upon the exterior of the thermoplastic
material to soften it, introducing into the cold 60 member.
gun barrel a heated, softened hollow cylinder of
6. A device for taking an impression of the in
said material, and exerting ?uid pressure upon
terior of a gun barrel to determine the condition
the interior of the hollow cylinder to cause its
of its surfaces, said device comprising an elon
outer surface to take an imprint of the interior
gated member having a port which leads to its
of the gun barrel including the ri?ing grooves,
periphery
and provided with means for centering
whereupon the thermoplastic material sets with
it in the gun barrel, an in?atable bag fastened
out adhering to the interior of the gun barrel
to said member and having its interior in com
and may be withdrawn for inspection.
munication with said port, a hollow member of
2. The method of taking an impression of the
thermoplastic material consisting essentially of
ri?ed interior of a gun'barrel to determine the
1. The method of taking an impression of the
ri?ed interior of a gun barrel to determine the
condition of its surfaces, said. method comprising,
condition of its surfaces, said method comprising,
providing a thermoplastic material consisting es
sentially of a solid wax and a resinous substance
of high molecular weight, heating the material
to soften it, introducing into thecold vgun barrel 75
a solid wax and a resinous substance of high
molecular weight located on the outside of said
bag, and means for causing ?uid under pressure
to flow through the port to in?ate the bag.
ALEXIS E. USHAKOEE.
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