U.S. patent application number 16/860100 was filed with the patent office on 2020-08-13 for high speed necking configuration.
The applicant listed for this patent is Crown Packaging Technology, Inc.. Invention is credited to Paul Robert Dunwoody, Ian K. Scholey.
Application Number | 20200254506 16/860100 |
Document ID | 20200254506 / US20200254506 |
Family ID | 1000004784845 |
Filed Date | 2020-08-13 |
Patent Application | download [pdf] |
United States Patent
Application |
20200254506 |
Kind Code |
A1 |
Dunwoody; Paul Robert ; et
al. |
August 13, 2020 |
HIGH SPEED NECKING CONFIGURATION
Abstract
A horizontal can necking machine assembly includes a plural of
main turrets and a plural of transfer starwheels. Each main turret
includes a main turret shaft, a main gear mounted on the main
turret shaft, a pusher assembly, and a die capable of necking a can
body upon actuation of the turret shaft. Each transfer starwheel
includes a transfer shaft and a transfer gear mounted on the
transfer shaft. The main gears are engaged with the transfer gears
such that lines through the main gear center and the centers of
opposing transfer gears form an included angle of less than 170
degrees, thereby increasing the angular range available for necking
the can body. The main turrets and transfer starwheels may operate
to neck and move at least 2800 cans per minute, and each pusher
assembly may have a stroke length relative to the die that is at
least 1.5 inches.
Inventors: |
Dunwoody; Paul Robert;
(Oxfordshire, GB) ; Scholey; Ian K.; (Tankersley,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Crown Packaging Technology, Inc. |
Alsip |
IL |
US |
|
|
Family ID: |
1000004784845 |
Appl. No.: |
16/860100 |
Filed: |
April 28, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15928984 |
Mar 22, 2018 |
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16860100 |
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15088691 |
Apr 1, 2016 |
9968982 |
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15928984 |
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14070954 |
Nov 4, 2013 |
9308570 |
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15088691 |
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12109176 |
Apr 24, 2008 |
8601843 |
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14070954 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B21D 51/2615 20130101;
B21D 51/2638 20130101; B21D 51/2692 20130101 |
International
Class: |
B21D 51/26 20060101
B21D051/26 |
Claims
1. A horizontal beverage can necking machine assembly for forming
necked beverage can bodies suitable for forming a seam with a
beverage can end, the assembly comprising multiple horizontal
necking stages adapted for necking at least 3000 beverage can
bodies per minute; each one of the main turrets including a
substantially horizontal main turret shaft, a main turret starwheel
having plural main pockets adapted for carrying can bodies, and a
main gear adapted to drive the main turret shaft;, each one of the
main pockets having a necking assembly including a necking die;
wherein each one of the main turrets is configured to supply
compressed air into the can body upon contact of the can body with
the necking assembly; each one of the transfer turrets including a
substantially horizontal transfer turret shaft, a transfer turret
starwheel having plural starwheel pockets adapted for carrying can
bodies, and a transfer gear adapted to drive the transfer shaft;
the main turrets and the transfer turrets being arranged such that
the main turret gears and transfer turret gears form a sawtooth
configuration; each one of the main gears formed of a composite
material comprising a plastic and each one of the transfer gears
formed of a composite material comprising a plastic such that main
gears and transfer gears are configured to operate without being
disposed in an oil-tight chamber; wherein the sawtooth
configuration of the main turrets and the transfer turrets provides
a greater necking operative zone compared with a necking operative
zone of in-line turret necking machines.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No.
15/928,984, filed Mar. 22, 2018, which is a continuation of
application Ser. No. 15/088,691, filed Apr. 1, 2016, which is a
continuation of application Ser. No. 14/070,954, filed Nov. 4,
2013, now U.S. Pat. No. 9,308,570, which is a continuation of
application Ser. No. 12/109,176, filed Apr. 24, 2008, now U.S. Pat.
No. 8,601,843, and is related by subject matter to the inventions
disclosed in the following commonly assigned applications: U.S.
patent application Ser. No. 12/109,031, filed on Apr. 24, 2008 and
entitled "Apparatus For Rotating A Container Body", now issued U.S.
Pat. No. 7,997,111, U.S. patent application Ser. No. 12/108,950
filed on Apr. 24, 2008 and entitled "Adjustable Transfer Assembly
For Container Manufacturing Process", now U.S. Pat. No. 8,245,551,
U.S. patent application Ser. No. 12/109,058, filed on Apr. 24, 2008
and entitled "Distributed Drives for A Multi-Stage Can Necking
Machine", now U.S. Pat. No. 8,464,567, U.S. patent application Ser.
No. 12/108,926, filed on Apr. 24, 2008 and entitled "Container
Manufacturing Process Having Front-End Winder Assembly", now U.S.
Pat. No. 7,770,425, and U.S. patent application Ser. No.
12/109,131, filed on Apr. 24, 2008 and entitled "Systems And
Methods For Monitoring And Controlling A Can Necking Process," now
U.S. Pat. No. 7,784,319. The disclosure of each application is
incorporated by reference herein in its entirety.
FIELD OF THE TECHNOLOGY
[0002] The present technology relates to a multi-stage can necking
machine. More particularly, the present technology relates to a
horizontal multi-stage can necking machine configured for high
speed operations.
BACKGROUND
[0003] Metal beverage cans are designed and manufactured to
withstand high internal pressure--typically 90 or 100 psi. Can
bodies are commonly formed from a metal blank that is first drawn
into a cup. The bottom of the cup is formed into a dome and a
standing ring, and the sides of the cup are ironed to a desired can
wall thickness and height. After the can is filled, a can end is
placed onto the open can end and affixed with a seaming
process.
[0004] It has been conventional practice to reduce the diameter at
the top of the can to reduce the weight of the can end in a process
referred to as necking. Cans may be necked in a "spin necking"
process in which cans are rotated with rollers that reduce the
diameter of the neck. Most cans are necked in a "die necking"
process in which cans are longitudinally pushed into dies to gently
reduce the neck diameter over several stages. For example, reducing
the diameter of a can neck from a conventional body diameter of 2
11/16.sup.th inches to 2 6/16.sup.th inches (that is, from a 211 to
a 206 size) often requires multiple stages, often 14.
[0005] Each of the necking stages typically includes a main turret
shaft that carries a starwheel for holding the can bodies, a die
assembly that includes the tooling for reducing the diameter of the
open end of the can, and a pusher ram to push the can into the die
tooling. Each necking stage also typically includes a transfer
starwheel shaft that carries a starwheel to transfer cans between
turret starwheels.
[0006] Multi-stage can necking machines are limited in speed.
Typically, commercial machines run at a rate of 1200-2500 cans per
minute. While this is a high rate, there is a constant need to
produce more and more cans per minute.
[0007] Also, concentricity of cans is important. A small
misalignment at the beginning of the necking stages may result in
concentricity problems between the can body and neck. For
illustration, a difference in the centers of 0.020 inches (twenty
thousandths) could result in a weak seam or even result in an
insufficiently seamed can.
SUMMARY
[0008] A horizontal can necking machine assembly may include a
plural of main turrets and a plural of transfer starwheels. Each
main turret may include a main turret shaft, a main gear mounted
proximate to an end of the main turret shaft, a pusher assembly,
and a die capable of necking a can body upon actuation of the
turret shaft. Each transfer starwheel may include a transfer shaft
and a transfer gear mounted proximate to an end of the transfer
shaft. The transfer starwheels may be located in an alternating
relationship with the main turrets, and the main gears may be
engaged with the transfer gears such that lines through the main
gear center and the centers of opposing transfer gears form an
included angle of less than 170 degrees, thereby increasing the
angular range available for necking the can body. The saw tooth
configuration of turret and transfer shafts that provides this
included angle yields, compared with configurations defining a 180
degree included angle, increased can residence time in the
operational zone for a given rotational speed, which increased time
enables longer or slower spindle stroke, and/or higher can
throughput for a given residence time, or a combination thereof. In
this regard, the main turrets and transfer starwheels may be
operative to neck and move at least 2800 cans per minute, and each
pusher assembly may have a stroke length relative to the die that
is at least 1.5 inches, and preferably 3400 cans per minute at a
stroke length of 1.75 inches.
[0009] A die for necking a can body may include a neck portion, a
body portion, and a transition portion. The necking portion may
have an inner wall that defines a cylinder having a first diameter.
The body portion may have an inner wall that defines a cylinder
having a second diameter. The transition portion may have an inner
wall that smoothly transitions from the inner wall of the neck
portion to the inner wall of the body portion. The first diameter
is larger than the second diameter, and the neck portion is at
least 0.125 inches long, and preferably 0.375 inches long.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view depicting a multi-stage can
necking machine;
[0011] FIG. 2 is a perspective view depicting a necking station and
gear mounted on a main turret shaft of the multi-stage necking
machine shown in FIG. 1, with surrounding and supporting parts
removed for clarity;
[0012] FIG. 3 is a perspective view depicting a transfer starwheel
and gear mounted on a starwheel shaft of the multi-stage necking
machine shown in FIG. 1, with surrounding and supporting parts
removed for clarity;
[0013] FIG. 4 is a partial expanded view depicting a section of the
multi-stage can necking machine shown in FIG. 1;
[0014] FIG. 5 is a perspective view depicting a back side of a
multi-stage can necking machine having distributed drives;
[0015] FIG. 6A is a perspective view depicting a forming die;
[0016] FIG. 6B is a cross-sectional view of the forming die
depicted in FIG. 6A;
[0017] FIG. 7 is a schematic illustrating a machine having
distributed drives; and
[0018] FIG. 8 is a partial expanded view depicting gear teeth from
adjacent gears engaging each other.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0019] A preferred configuration for driving a multi-stage can
necking machine is provided. The multi-stage can necking machine
incorporates technology that overcomes the many shortcomings of
known multi-stage can necking machines. The present invention is
not limited to the disclosed configuration, but rather encompasses
use of the technology disclosed, in any manufacturing application
according to the language of the claims.
[0020] As shown in FIG. 1, a multi-stage can necking machine 10 may
include several necking stages 14. Each necking stage 14 includes a
necking station 18 and a transfer starwheel 22. Each one of the
necking stations 18 is adapted to incrementally reduce the diameter
of an open end of a can body, and the transfer starwheels 22 are
adapted to transfer the can body between adjacent necking stations
18, and optionally at the inlet and outlet of necking machine 10.
Conventional multi-stage can necking machines, in general, include
an input station and a waxer station at an inlet of the necking
stages, and optionally include a bottom reforming station, a
flanging station, and a light testing station positioned at an
outlet of the necking stages. Accordingly, multi-stage can necking
machine 10, may include in addition to necking stages 14, other
operation stages such as an input station, a bottom reforming
station, a flanging station, and a light testing station of the
type that are found in conventional multi-stage can necking
machines (not shown). The term "operation stage" or "operation
station" and its derivative is used herein to encompass the necking
station 14, bottom reforming station, a flanging station, and a
light testing station, and the like. Preferably, multi-stage can
necking machine 10 is operative to neck and move at least 2800 cans
per minute, more preferably at least 3200 cans per minute, and even
more preferably at least 3400 cans per minute.
[0021] FIG. 2 is a detailed view depicting operative parts of one
of the necking stations 18. As shown, each necking station 18
includes a main turret 26, a set of pusher rams 30, and a set of
dies 34. The main turret 26, the pusher rams 30, and the dies 34
are each mounted on a main turret shaft 38. As shown, the main
turret 26 has a plurality of pockets 42 formed therein. Each pocket
42 has a pusher ram 30 on one side of the pocket 42 and a
corresponding die 34 on the other side of the pocket 42. In
operation, each pocket 42 is adapted to receive a can body and
securely holds the can body in place by mechanical means, such as
by the action pusher ram and the punch and die assembly, and
compressed air, as is understood in the art. During the necking
operation, the open end of the can body is brought into contact
with the die 34 by the pusher ram 30 as the pocket 42 on main
turret 26 carries the can body through an arc along a top portion
of the necking station 18.
[0022] Die 34, in transverse cross section, is typically designed
to have a lower cylindrical surface with a dimension capable of
receiving the can body, a curved or angled transition zone, and a
reduced diameter (relative to the lower cylindrical surface) upper
cylindrical surface above the transition zone. During the necking
operation, the can body is moved up into die 34 such that the open
end of the can body is placed into touching contact with the
transition zone of die 34. As the can body is moved further upward
into die 34, the upper region of the can body is forced past the
transition zone into a snug position between the inner reduced
diameter surface of die 34 and a form control member or sleeve
located at the lower portion of pusher ram 30. The diameter of the
upper region of the can is thereby given a reduced dimension by die
34. A curvature is formed in the can wall corresponding to the
surface configuration of the transition zone of die 34. The can is
then ejected out of die 34 and transferred to an adjacent transfer
starwheel. U.S. Pat. No. 6,094,961, which is incorporated herein by
reference, discloses an example necking die used in can necking
operations.
[0023] As best shown in FIG. 2, a main turret gear 46 (shown
schematically in FIG. 2 without teeth) is mounted proximate to an
end of shaft 38. The gear 46 may be made of suitable material, and
preferably is steel.
[0024] As shown in FIG. 3, each starwheel 22 may be mounted on a
shaft 54, and may include several pockets 58 formed therein. The
starwheels 22 may have any amount of pockets 58. For example each
starwheel 22 may include twelve pockets 58 or even eighteen pockets
58, depending on the particular application and goals of the
machine design. Each pocket 58 is adapted to receive a can body and
retains the can body using a vacuum force. The vacuum force should
be strong enough to retain the can body as the starwheel 22 carries
the can body through an arc along a bottom of the starwheel 22.
[0025] As shown, a gear 62 (shown schematically in FIG. 3 without
teeth) is mounted proximate to an end of the shaft 54. Gear 62 may
be made of steel but preferably is made of a composite material.
For example, each gear 62 may be made of any conventional material,
such as a reinforced plastic, such as Nylon 12.
[0026] As also shown in FIG. 3, a horizontal structural support 66
supports transfer shaft 54. Support 66 includes a flange at the
back end (that is, to the right of FIG. 3) for bolting to an
upright support of the base of machine 10 and includes a bearing
(not shown in FIG. 3) near the front end inboard of the transfer
starwheel 22. Accordingly, transfer starwheel shaft 54 is supported
by a back end bearing 70 that preferably is bolted to upright
support 52 and a front end bearing that is supported by horizontal
support 66, which itself is cantilevered from upright support 52.
Preferably the base and upright support 52 is a unitary structure
for each operation stage.
[0027] FIG. 4 illustrates a can body 72 exiting a necking stage and
about to transfer to a transfer starwheel 22. After the diameter of
the end of a can body 72 has been reduced by the first necking
station 18a shown in the middle of FIG. 4, main turret 26 of the
necking station 18a deposits the can body into a pocket 58 of the
transfer starwheel 22. The pocket 58 then retains the can body 72
using a vacuum force that is induced into pocket 58 from the vacuum
system described in co-pending application (Attorney Docket Number
CC-5163), which is incorporated herein by reference in its
entirety, carries the can body 72 through an arc over the
bottommost portion of starwheel 22, and deposits the can body 72
into one of the pockets 42 of the main turret 26 of an adjacent
necking station 18b. The necking station 18b further reduces the
diameter of the end of the can body 72 in a manner substantially
identical to that noted above.
[0028] Machine 10 may be configured with any number of necking
stations 18, depending on the original and final neck diameters,
material and thickness of can 72, and like parameters, as
understood by persons familiar with can necking technology. For
example, multi-stage can necking machine 10 illustrated in the
figures includes eight stages 14, and each stage incrementally
reduces the diameter of the open end of the can body 72 as
described above.
[0029] As shown in FIG. 5, when the shafts 38 and 54 are supported
near their rear ends by upright support 52, and the ends of the
shafts 38 and 54 preferably are cantilevered such that the gears 46
and 62 are exterior to the supports 52. A cover (not shown) for
preventing accidental personnel contact with gears 46 and 62, may
be located over gears 46 and 62. As shown, the gears 46 and 62 are
in mesh communication to form a continuous gear train. The gears 46
and 62 preferably are positioned relative to each other to define a
zig-zag or saw tooth configuration. That is, the main gears 46 are
engaged with the transfer starwheel gears 62 such that lines
through the main gear 46 center and the centers of opposing
transfer starwheel gears 62 form an included angle of less than 170
degrees, preferably approximately 120 degrees, thereby increasing
the angular range available for necking the can body. In this
regard, because the transfer starwheels 22 have centerlines below
the centerlines of main turrets 26, the operative portion of the
main turret 26 (that is, the arc through which the can passes
during which the necking or other operation can be performed) is
greater than 180 degrees on the main turret 26, which for a given
rotational speed provides the can with greater time in the
operative zone. Accordingly the operative zone has an angle
(defined by the orientation of the centers of shafts 38 and 54)
greater than about 225 degrees, and even more preferably, the angle
is greater than 240 degrees. The embodiment shown in the figures
has an operative zone having an angle of 240 degrees. In general,
the greater the angle that defines the operative zone, the greater
the angular range available for necking the can body.
[0030] In this regard, for a given rotational speed, the longer
residence time of a can in the operative zone enables a longer
stroke length for a given longitudinal speed of the pusher ram. For
example, with the above identified configuration, the pusher ram 30
may have a stroke length relative to the die 34 of at least 1.5
inches. Preferably, the pusher ram 30 will have a stroke length
relative to the die 34 of at least 1.625 inches and even more
preferably the stroke length is at least 1.75 inches. For the
embodiment shown in the figures, the stroke length is approximately
1.75 inches.
[0031] The angular range available for necking of greater than 180
degrees enables the die used to reduce the diameter of the end of
the can body to be designed to improve the concentricity of the can
end. As shown in FIGS. 6A and 6B, the die 34 includes a throat
portion 78, a body portion 82 and a transition portion 86. As
shown, the throat portion 78 has an inner surface 90 that defines a
cylinder having a first diameter, the body portion 82 has an inner
surface 94 that defines a cylinder having a second diameter, and
the transition portion 86 has an inner surface 98 that extends
smoothly (and maybe curved) from the inner surface 90 of the throat
portion 78 to the inner surface 94 of the body portion 82. The
first diameter should be large enough to receive the can body and
the second diameter should be sized so that the diameter of the end
of the can body can be reduced to a desired diameter.
[0032] To help improve the concentricity of the can end the throat
portion preferably has a length of at least 0.125 inches, more
preferably a length of at least 0.25 inches and even more
preferably a length of at least 0.375 inches. The embodiment
illustrated in the figures has a throat length of approximately
0.375 inches. Furthermore, an inlet 102 of the throat portion 78
may be rounded.
[0033] During operation of conventional stroke machines, the first
part of the can that touches the die is the neck or necked rim. Any
error in the neck portion often becomes worse, throughout the
necking stages. In the long stroke machine illustrated herein, when
the can goes into the die, it first locates itself in the die
before it touches the transition portion. Therefore, by having a
longer throat portion 78 compared with the prior art, the die 34 is
able to center the can body prior to necking. Additionally, by
having a longer throat portion 78, the die 34 is able to seal the
compressed air sooner. Until the can is sealed, the compresses air
blows into the ambient atmosphere, which can be costly.
[0034] Referring back to FIG. 5, the multi-stage can necking
machine 10 may include several motors 106 to drive the gears 46 and
62 of each necking stage 14. As shown, there preferably is one
motor 106 per every four necking stages 14, as generally described
in copending application ______ (Attorney docket number CC-5164).
Each motor 106 is coupled to and drives a first gear 110 by way of
a gear box 114. The motor driven gears 110 then drive the remaining
gears of the gear train. By using multiple motors 106, the torque
required to drive the entire gear train can be distributed
throughout the gears, as opposed to prior art necking machines that
use a single motor to drive the entire gear train. In the prior art
gear train that is driven by a single gear, the gear teeth must be
sized according to the maximum stress. Because the gears closest to
the prior art drive gearbox must transmit torque to the entire gear
train (or where the single drive is located near the center on the
stages, must transmit torque to about half the gear train), the
maximum load on prior art gear teeth is higher than the maximum
tooth load of the distributed gearboxes according to the present
invention. The importance in this difference in tooth loads is
amplified upon considering that the maximum loads often occur in
emergency stop situations. A benefit of the lower load or torque
transmission of gears 46 and 62 compared with that of the prior art
is that the gears can be more readily and economically formed of a
reinforced thermoplastic or composite, as described above.
Lubrication of the synthetic gears can be achieved with heavy
grease or like synthetic viscous lubricant, as will be understood
by persons familiar with lubrication of gears of necking or other
machines, even when every other gear is steel as in the presently
illustrated embodiment. Accordingly, the gears are not required to
be enclosed in an oil-tight chamber or an oil bath, but rather
merely require a minimal protection against accidental personnel
contact
[0035] Each motor 106 is driven by a separate inverter which
supplies the motors 106 with current. To achieve a desired motor
speed, the frequency of the inverter output is altered, typically
between zero to 50 (or 60 hertz). For example, if the motors 106
are to be driven at half speed (that is, half the rotational speed
corresponding to half the maximum or rated throughput) they would
be supplied with 25 Hz (or 30 Hz).
[0036] In the case of the distributed drive configuration shown
herein, each motor inverter is set at a different frequency.
Referring to FIG. 7 for example, a second motor 120 may have a
frequency that is approximately 0.02 Hz greater than the frequency
of a first motor 124, and a third motor 128 may have a frequency
that is approximately 0.02 Hz greater than the frequency of the
second motor 120. It should be understood that the increment of
0.02 Hz may be variable, however, it will be by a small percentage
(in this case less than 1%).
[0037] The downstream motors preferably are preferably controlled
to operate at a slightly higher speed to maintain contact between
the driving gear teeth and the driven gear teeth throughout the
gear train. Even a small freewheeling effect in which a driven gear
loses contact with its driving gear could introduce a variation in
rotational speed in the gear or misalignment as the gear during
operation would not be in its designed position during its
rotation. Because the operating turrets are attached to the gear
train, variations in rotational speed could produce misalignment as
a can 72 is passed between starwheel and main turret pockets and
variability in the necking process. The actual result of
controlling the downstream gears to operate a slightly higher speed
is that the motors 120, 124, and 128 all run at the same speed,
with motors 120 and 128 "slipping," which should not have any
detrimental effect on the life of the motors. Essentially, motors
120 and 128 are applying more torque, which causes the gear train
to be "pulled along" from the direction of motor 128. Such an
arrangement eliminates variation in backlash in the gears, as they
are always contacting on the same side of the tooth, as shown in
FIG. 8. As shown in FIG. 8, a contact surface 132 of a gear tooth
136 of a first gear 140 may contact a contact surface 144 of a gear
tooth 148 of a second gear 152. This is also true when the machine
starts to slow down, as the speed reduction is applied in the same
way (with motor 128 still being supplied with a higher frequency).
Thus "chattering" between the gears when the machine speed changes
may be avoided.
[0038] In the case of a machine using one motor, reductions in
speed may cause the gears to drive on the opposite side of the
teeth. It is possible that this may create small changes in the
relationship between the timing of the pockets passing cans from
one turret to the next, and if this happens, the can bodies may be
dented.
[0039] The present invention has been described by illustrating
preferred embodiments. The present invention is not limited to an
configuration or dimensions provided in the specification, but
rather should be entitled to the full scope as defined in the
claims.
* * * * *