Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
BACRGROUND AND SUMMARY OF TE~E INvEhTIoN
The present invention relates to an improved
method and apparatus for making a necked container and to
the necked container formea thereby. More particularly, the
invention relates to an improved method and apparatus for
making a necked container wherein one end of the container
is necked-in at least 15% from the original container
diameter so as to be useful as an aersol can, for example.
In the past there have generally been ~wo basic
kinds of necked aerosol containers: those made of steel
sheet material such as tin plate, and those made of
aluminum. In the case of s~eel sheet material, one for~ of
construction for the aerosol containers has been the
three-piece container having a cylindrical container body
with a longitudinally extending soldered or welded lap joint
and with a dome-shaped top and a bottom seamed thereon.
Steel sheet material aerosol containers have also been
formed out of flat steel sheet by a method called drawn and
ironed. On such cans a dome-shaped top i5 mounted to form a
; 20 ~ two-plece container. Another drawn and ironed technique
involves forming a steel cup, cutting a hole in the cup and
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` curling the adjacent edge to form a necked top and ~hen
seaming a bottom to the cup.
Necked aerosol containers of aluminum may be made
by a method which involves forming so-called monobloos from
an aluminum slug into a cup. The top of the cup i5 formed
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with a relatively small opening and an outside curl on which
an aerosol valve i5 mounted. A drawn and ironed process may
also be used to form aluminum aerosol containers from flat
sheets of aluminum. A two-piece aluminum can formed by such
a method has a dome-shaped top which is mounted the same way
as on a tinplate three-piece container. Aluminum aerosol
containers may also be integxally formed with a top having
a relatively small opening for an aerosol valve and with the
bottom of the container being seamed on to form a two-piece
container.
Thus, it is known to make necked aerosol
containers either by providing a cylindrical container~body
with a special end or by shaping the end of a container
particularly when the container is formed of readily
workable metal, such as aluminum. Howeverl until recently
the forming of a dome from a steel can body has been
impractical ~rom a commercial standpoint.
It is known to reduce the diameter of an end
portion of a can body ~y a series of necking-in operations.
However, in such bodies in lieu of the conventional smooth
dome appearance there has generally been either a series of
.
steps or a very wrinkled appearance.
U. S. Patent No. 4,261,193 discloses a method and
apparatus for making a necked steel aerosol container having
an integral dome wherein the container is formed by welding
the overlapping longitudinally extending edges of a steel
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sheet which has been formed into a cylindrical can body and
thereafter progressively necking-in the welded can body. In
this known process the overlapped edges of the cylindrical
container body are welded together by a conventional welding
process such as electrical resistance welding. With such a
welded cylindrical can body the wall thickness of the can
body is greater at the welded side seam than it is elsewhere
about the circumference of the can bo~y. Thus, necking of
this known type of cylindrical container body is
problematical in that it is not commercially feasible to
orient the lap weld side seam with the tooling during the
necking operations and therefore in the apparatus disclo~ed
in the aforesaid patent, it is necessary that the outside
tools be permitted to float radially in order to maintain
the required clearance at all circumferential point~ between
the tools of each set of tooling. The greater thickness of
the lap weld side seam may also adversely affect the
appearance of the necked container in that the uneven or
discontinuous nature of the weld and subsequent wrinkles
from forming may be readily visible by the casual observer.
The method and apparatus for making a necked container
disclosed in the aforesaid patent are also disadvantageous
in that they require a complete assembly and disassembly of
the lap welded can body with respect to each of a plurality
of sets of necking tools. Thus, either the can body or
entire sets of tools must be transferred from station-to-station
during the necking-in steps which can be a relatively slow
process subject to damaging either the cans or the tools.
An object of the present invention is to provide
an improved method and apparatus for making a necked aerosol
container for an aerosol can, for example, which avoid the
aforementioned disadvantages of the prior art~ More ;.
particularly, an object of the invention is to provide an
improved method and apparatus for making a necked container
which may be ~ormed from welded sheet material thereby
providing a container which is relatively low in cost as
compared with the prior containers such as the aluminum
monobloc container.
A further object of the invention is to provide an
improved method and apparatus for making a necked container
having an integral dome wherein the container is formed from
a cylindrical can body having a longitudinal side seam and
wherein the dome is formed by a progressive necking-in
process such that the dome-shaped configuration is smooth
instead of being providèd with a series of steps or a
wrinkled appearance.
An additional object of the present invention is
to provide an improved method and apparatus for making a
necked container such that it is possible to progressively
neck-in the end of a welded steel cylindrical can body
without getting a wrinkle or an S-curve during necking and
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01 without necessitating the use of sets of tooling that
02 float radially and that must be completely exchanged
03 with each successive necking-in step.
04 These and other objec-ts of the present
05 invention are attained by providing a tubular member
06 about a mandrel having a free end portion with a
07 dome-shaped surface, performing a plurality of
08 necking-in operations on the welded tubular member
09 while the member is arranged about the mandrel to
progressively reduce the diameter of a free end
11 portion of the tubular member at least 15% from the
12 original diameter of the tubular member with the
13 necked-in end of the tubular member having a
14 dome-shaped configuration, the plurality of necking-in
operations including a first necking-in operation of
16 reducing the diameter of the free end portion of the
17 tubular member and forming an in-termediate portion
18 between the reduced diameter free end portion and the
19 remainder of the tubular member over a portion of the
dome-shaped surface of the mandrel and a further
21 necking-in operation of further reducing the diameter
22 of the free end portion of the tubular member and
23 further forming the intermediate portion over the
24 dome-shaped surface of the mandrel to increase the
extent of the intermediate portion.
26 An apparatus of the invention for
27 progressively necking-in an end portion of the butt
28 welded tubular member comprises a first inside tool of
29 a first diameter, a free end portion of said inside
tool having a dome-shaped surface, a plurality of
31 second inside tools each having a second diameter
32 which is less than the first diameter of the first
33 -5-
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01 inside tool and having a free end portion for
02 positioning adjacent the dome-shaped surface of the
03 first inside tool with the dome-shaped ~urface
04 extending between the first diameter of the firs-t
05 inside tool and the second diameter of the second
06 inside tool, the second diameter of the second inside
07 tool progressively decreasing so that the extent of
08 the dome-shaped surface between the first and second
09 diameter progressively increases, and a plurality of
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outside tools cooperable with the first inside tool and
respective ones of the second inside tools.
In a disclosed embodiment of the apparatus, each
of the plurality of outside tools have an internal
5 configuration with a first port:ion cooperable with the first
diameter of the first inside tc~ol, a second portion
cooperable with the dome-shaped surface extending between
the first diameter of the firsl: inside tool and second
diameters of one of the second inside tools and a third
portion cooperable with the second diameter of one of the ;
second inside tools. In the disclosed embodiment, the
second diameter of the second inside tools progressivel~
decreases to a diameter on the order of one-half of the
first diameter.
Means are provided for moving one of the first
inside tool and a cooperable pair of a second inside tool
and an outside tool with respect to the other for effecting
necking-in of the end portion of the tubular member. In the
illustrated embodiment, the means for moving comprises a
press ram which moves the cooperable pair with respect to
the first inside tool in a direction along the longitudinal
axis of a tubular member to be necked-in which is located
about the first inside tool.
According to a further feature of the invention,
means are provided for mountin~ the second inside tool of
the cooperable pair in a leading and relatively movable
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; position with respect to the outside tool so that with
relative movement of the cooperable pair with respect to the
first inside tool, the second inside tool reaches a position
adjacent the dome-shaped surface of the first inside tool
while the outside tool continues to move with respect ~o
both the first and second inside tools for effecting
necking-in of the end portion of the tubular me~ber. The
means for mounting the second inside tool of the cooperable
pair in a leading and relatively movable position with
respect to the outside tool includes a spring f~r yieldably
biasing the second inside tool in the leading position.
As an additional feature of the invention, the
second inside tool of the cooperable pair includes an i,
abutment member located centrally in its free end portion
for contacting a portion of the first inside tool when the
second inside tool is positioned adjacent the dome-shaped
surface. A recess is provided in the center of the free end
portion of the first inside tool for receiving the abutment
member when the second inside tool is positioned adjacent
the dome-shaped surface. A spacer is located in the recess
for contacting the abutment member to control the relative
positions of the first and second inside tools.
With the method and apparatus of the invention, it
is possible to progressively neck-in a free end portion of
the butt welded tubular member to form a dome-shaped surface
without the use of outside tools which float radially and
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01 without getting wrinkles or an S-curve during
02 necking-in. This necking-in process is facilitated by
03 the fact that the thickness of the butt weld in the
04 can body is the same or essentially the same as the
05 wall thickness of the can body outside the weld area,
06 and by the relatively small weld heat-affected zone
07 and minimal degradation of base material properties
08 associated therewith which result from welding with a
09 high energy density welding process such as laser
welding or electron beam welding wherein the energy
11 density is at least 106 per square inch.
12 In accordance with a further embodiment of
13 the present invention a necked tubular member is
14 provided having a cylindrica:L body with one end
thereof being necked-in, a laser butt welded joint
16 extending longitudinally in the tubular member in both
17 the cylindrical body and the necked-in end, the
18 thickness of the butt weld of the joint being the same
19 or essentially the same as the wall thickness of the
tubular member outside the weld area, the laser butt
21 welded joint having a relatively small weld heat
22 affected zone and minimal degradation of base material
23 properties associated therewith, the one end of the
2~ welded tubular member being neck-in over a dome-shaped
surface of a single mandrel by performing a plurality
26 of necking-in operations on the welded tubular member
27 while the member is arranged about the mandrel to
28 progressively necked-in the tubular member to a
29 diameter which is reduced by at least approximately
15~ from the original diameter of the tubular member
31 with the necked-in end of the tubular member having a
32 smooth dome-shaped configuration.
33 These and other objects, features and
34 advantages of the present invention will become more
apparent from the following description when taken in
36 connection with the
37 _9_
2~
01 accompanying drawings which show, for purposes of
02 illustration only, several embodiments in accordance
03 with the invention.
04 BRIEF DESCRIPTION OF THE DRAWINGS
05 Figure 1 is a side elevational view of one
06 embodiment of an aerosol container made with the
07 method and the apparatus of the invention;
08 Figure 2 is a sectional view taken through
09 the portion of the upper, necked end of a butt welded
tubular member which has been necked-in to form an
11 aerosol container as shown in Figure 1 and wherein the
12 tubular member is shown in the various positions as i-t
13 is progressively necked-in:
14 Figure 3 is a sectional view of one
embodiment o-f an apparatus of the invention for making
16 -the aerosol container shown in Figure 1 and wherein
17 the press ram is shown in its upper position;
18 Figure 3a is a sectional view of the
19 apparatus of Figure 3 but with the press ram in its
lower position;
21 Figure 3b is a sectional view of a portion
22 of the apparatus as shown in Figure 3a and
23 illustrating a portion of the end of a tubular member
24 being necked by the apparatus;
Figure 4a is a schematic illus-tration of
26 one side of the upper portion of a tubular member
27 which has been necked-in to form an aerosol container
28 as shown in Figure l;
29 Figure 4b is a schematic illustration
similar to Figure 4a and graphically illustrating
31 trimming of the free end of the upper necked-in
32 portion of the tubular member;
33 Figure 4c is a schematic illustration
34 similar to
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Figure 4b and illustrating the trimmed tubular ~ember after
the necked-in portion has been beaded inwardly;
Figure 4d is a schematic illustratio.n similar to
Figure 4c and wherein the upper end of the necked-in tubular
member is curled inwardly; and
; ; Figure 5 is a cross sectional view of the
; container of Figure 1 taken along the line V-V.
DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS
Referring now to the drawings, it will be seen
that there is illustrated in Figure 1 a necked container 1
suitable for use as an aerosol can. The container 1 has an
appearance like that of an aluminum aerosol can produced
from the so-called monoblocs or by a drawn and ironed
process but differs therefrom in that the can body 2 is made
by the method of the invention wherein a sheet of material
is formed into a generally cylindrical tubular member and
the adjacent longitudinally extending edges thereof are butt .
welded to form the side seam 3 and thereafter the welded
tubular member is arranged about a mandrel and an end
portion thereof progressively necked-in over a dome-shaped
surface of the mandrel ac discussed more fully below. The
upper, necked-in end of the welded tubular body 2 is
necked-in to a diameter which is reduced by at least
approximately 1~% from the original diameter of the tubular
member and, more particularly, in the disclosed embodiment,
is reduced to a diameter on the order of one-half of the
~æ~s~
diameter of the tubular member, with the necked-in end
having a smooth dome-shaped configuration. The upper free
end of the necked-in welded tubular member is curled as
shown at 5 for recieving a conventional aerosol valve
S - assembly (not shown) which may be secured to the upper end
of the tubular member by a conventional seam.
As illustrated in Figure l, the container body 2
is cylindrical over a major portion of its height with the
lower end thereof being closed by a conventional end unit 6
secured to the body 2 by means of a conventional seam 7.
The sheet material used to form the can body 2 is a plain
low carbon steel sheet metal such as a single reduced,
T-4CA, 75 lb. per base box material having a thickness ~f
i7,~_2~ ?~^7
.0083 inch. A double reduced material, such as DR-9, could
also be used where a higher tensile strength is desired.
Flat blanks of this sheet material are formed into a
generally cylindrical configuration with the opposed
longitudinally extending edges in abutting relationship for
laser butt welding by a Z-bar guide apparatus as disclosed
! 20 in U.S. Patent Nos. 4,272,004 and 4,354,090. These
apparatus have only recently made possible the successive,
high-speed laser butt welding of the longitudinally
extending edges of tubular members.
An apparatus of the invention for progressively
necking-in an end portion of a butt welded tubular member is
generally designated as B in Figure 3. Tbe apparatus
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comprises a first inside tool in the form of a stationary
cylindrical supporting mandrel 9 of a first diameter. The
upper, free end portion of the mandre:L has a smooth
dome-shaped surface 10 with a radius of curvature of 1.5
inches in the case of necking a welded tubular member 2.080
inches in diameter. The juncture 11 between the dome-shaped
surface 10 and the cylindrical side wall portion of the
mandrel 9 is provided with a radius of curvature of .125
; ` inch. The apparatus 8 further includes a plurality of
second inside tools or knockout plugs 12 each having a
second diameter which is less than the first diameter of the
mandrel 9 and havinq a lower, free end portion 13 for
positioning adjacent the dome-shaped surface 10 of mandrel 9
with the dome-shaped surface extending between the outer
diameter of the mandrel 9 and the diameter of the knockout
plug 12. The shape of the knockout plug 12 is changed with
each progressive diameter change or necking-in step as
discussed below. In particular, the outer diameter of the
cylindrical knockout plugs 12 progressively decrease with
each necking-in step so that the extent of the
dome-shaped surface between the Duter diameter of the
mandrel 9 and the knockout plug progressively increases~
The apparatus 8 further includes a plurality of
outside tools generally designated at 14 cooperable with the
mandrel 9 and respective ones of the knockout plugs 12
during necking-in of the end portion of a tubular member.
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While only one of the outside ~ools 14 and cooperating
knockout plug 12 are shown in the drawings, it is understood
that the apparatus comprises a plurality of sets or pairs of
these tools which may be mounted about a circle on a turret,
for example, or in a straight line on a suitable press as
discussed hereinafter for successive use as will be readily
apparent to the skilled artisan. However, since a single
mandrel 9 is used with each necking-in step, it is not
necessary to remove the tubular member from about the
mandrel during the various steps of the process. ~he
necking-in of the tubular member can thus be accomplished in
a simpler and faster manner subject to less damage as
compared with the prior art and without requiring mounting
of the outside tools so as to float radially.
Each outside toGl 14 includes a die piece 15 and a
die insert 16 whose size or shape changes with each
progressive diameter change or necking-in step. Each of the
plurality of outside tools 14 have an internal configuration
with a first cylindrical portion cooperable with the outer
diameter of the cylindrical mandrel 9, a second inwardly
tapered portion 18 cooperable with the dome-shaped surface
10 extending between the outer diameter of the mandrel 9 and
the outer diameter of the adjacent knockout plug 12, and a
third portion in the form of a cylindrical surface
cooperable with the outer diameter of one of the knockout
plugs 12.
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As depicted in Fi~ure 3, an outside tool 14 and a
cooperable knockout plug 12 are mounted on a press ram 20 of
a standard 35 ton straight side punch press for movement
with respect to the stationary mandrel 9. The knockou~ plug
12 of the cooperable pair is normally biased in a leading
and relatively movable position with respect to its
associated outside tool 1~ as illustrated in the upper
righthand portion of Figure 3. With downward movement of
the press ram 20, the knockout plug 12 reaches a position
adjacent the dome-shaped surface 10 of the mandrel 9 while
the outside tool 14 continues to move with respect to both
the knockout plug 12 and the mandrel 9 for effecting
~ necking-in of the end portion of the tubular member. In
; particular, the knockout plug 12 is carried at the lower end
of a knockout bolt 21 which extends through the press ram 20
and operates off a knockout bar 22 above the press ram. A
spring 23 yieldably biases the knockout plug in this leading
position as shown in Figure 3.
The knockout plug 12 has a central recess in its
lower end which accommodates an adjustiny abutment member 24
for contacting a portion of the mandrel 9 when the knockout
plug is positioned adjacent the dome-shaped surface 10
thereof. The lower end of the adjusting abutment member 24
is received in a central recess 25 in the upper end of the
mandrel 9. A spacer or shim 26 is located in the recess for
contacting the abutment member 24 to control the relative
positions of the mandrel 9 and knockout plug 12.
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A butt welded tubular member is necked-in at one
end with the apparatus 8 by arranging the welded cylindrica
tubular member about the mandrel 9 with a free end portion
of the tubular member to be necked-in adjacent the upper end
of the mandrel. The lower end of the tubular member rests
in a recess 27 in the base 28 of the apparatus. The punch
press is then actuated so that the press ram 20 moves
downwardly along the longitudinal axis of the ~andrel 9 and
tubular member. During this downward movement the knockout
plug 12 moves into the upper end of the tubular member to a
position adjacent the dome-shaped surface 10 of the mandrel
9 where its motion is arrested. The abutment member 24 is
adjusted and the thickness of the spacer shim 28 is selected
; so that the lower end of the knockout plug 12 contacts or is
il5 very close to the dome-shaped surface 10 in this working
- position. The juncture of the lower end surface of the
knockout plug 12 and the outer cylindrical surface thereof
is honed to a relatively small radius, .002-.003 inch, so
there may be close contact of the plug 12 with ~he mandrel 9
in the working position to ensure that the upper portion of
the tubular member is fed into the space between the
knockout plug 12 and the die insert 16 of the outside tool
14 as the press ram 20 continues its descent. Necking-in of
the tubular member is effected by this continued downward
movement of the outside tool 14 and press ram 14 after the
knockout plug 12 has contacted the mandrel 9.
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The extent of downward movement of the outside tool is
adjusted by means of the press setting t~ control the
tolerance between the die insert 16 and the mandrel 9 in
accordance with the thickness of the sheet material of the
tubular member. During the ups~ard movement.of the press ram
the outside tool 14 first moves upwardly with respect to the
stationary mandrel 9 while the knockout plug 12 remains
biased against the mandrel by the spring 23 until the press
ram contacts the knockout bar 22.
In the embodiment of the invention illustrated in
Figure 2, a tubular member having an initial diameter of
2.080 inches and a wall thickness of .0083 inch is
progressively necked-in over a series of 10 necking steps to
a diameter of 1.027 inches. That is, a 50.6% reduction in
lS the diameter of the tubular member i~ effected by reducing
. the diameter approximately 7 to 8~ during the initial
; necking steps and approx.imately 3 to 4% in the ~inal two
steps. The diameter of the necked-in portion, the radius of
curvature between the dome-shaped surface and the
cylindrical necked-in portion and the cumulative diameter
reduction with each necking step are illustrated in Table A.
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TAsLE A
Diameter Cumulative
Necking Necked-In Radius of Diameter
Step _ End Curvature Reduction
A 1.914 .250 .166
B 1.761 .213 .319
C 1.629 .181 .451
D 1.507 .154 .573
E 1.394 .131 .686
F 1.289 .111 .791
G 1.192 .094 .888
H 1.103 .080 .977
I 1.059 .030 1.021
J 1.027 .030 1.053
lS Thus, the method of making a necked-in tubular
member according to the inventisn comprises the steps of
; forming a sheet material into a generally cylindrical
i tubular member and butt welding the adjacent longitudinally
extending edges of the sheet, arranging the welded tubular
member about a mandrel having a free end portion with a
dome-shaped surface, reducing the diameter of a free end
portion of the tubular member and forming an intermediate
portion between the reduced diameter free end portion and
the remainder of the tubular member which extends along a
portion of the dome-shape~ surface of the mandrel, and
further reclucing the diametér of the free end portion of the
18 .!~
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tubular member and increasing the extent of the intermediate
portion along the dome-shaped surface of the mandrel. The
step of further reducing the diameter of the free end
- portion of the tubular member and increasing the step of the
in~ermediate portion along the dome-shaped surface of the
mandrel is repeated until the cliameter of the free end is at
least approximately 15~ less than the initial diameter. In
the illustrated example, the welded tubular member is
necked-in to a diameter on the order of one-half of the
original tube diameter. In anQther case, a tubular member
having an initial diameter of 1 12/16ths inch can be
necked-in to approximately 1 inch to accept a standard
aerosol valve assembly. The reduction in this last mentioned
example is approximately 40~.
~he reduced free end portion of the tubular member
is then trimmed to obtain a smooth working surface as
illustrated in Figure 4b. The trimmed end is thereafter
curved to form a standard size aerosol can opening upon
` ; which a conventional aerosol valve assembly can be mounted.
.
; 29 The free end may be curled outside in a conventional way or,
as illustrated in Figure 4d, it may be curled inside with
the trimmed edge tucked inside the curl to protect the raw
edge created by trimming from aggressive products, if any,
that the container might hold. As a preliminary step in the
curling operation, a rotary operating tool is used to bead
the neck inwardly at 29 to prepare and determine the flow
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direction of the material in the curling step. The beaded
neck is then rolled inwardly and collapsed by way of a
rotating curling tool or a punch like curling tool to form a
standard size aerosol can opening as illustrated in Figure
4d.
While I have shown and described several
embodiments in accordance with the invention, it is
understood that ~he same is not limited thereto but is
susceptible of numerous changes and modifications as would
be known to those skilled in the art, given the present
disclosure. For example, the upper portion of the necked
container need not be curled but could be threaded, for
example, to receive a threaded container closure. Further,
the sheet material of the butt welded tubular member need
not be steel but could be another metal such as aluminum or
even a non-metallic material. Also, while the dome-shaped
confi~uration of the necked tubular member is a smooth
curvilinear surface in the illustrated embodiment, this
dome-shaped configuration could have other forms such as
conical, etc. I therefore do not wish to be limited to the
; details shown and described herein but intend to cover all
such changes and modifications as are encompassed by the
` scope of the appended claims.
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