U.S. patent application number 09/800308 was filed with the patent office on 2002-09-05 for bag welding method and assembly for a bag filling station.
This patent application is currently assigned to OPTIMA Machinery Corporation. Invention is credited to Parsons, Ronald R., Schabel, Stefan.
Application Number | 20020121075 09/800308 |
Document ID | / |
Family ID | 25178045 |
Filed Date | 2002-09-05 |
United States Patent
Application |
20020121075 |
Kind Code |
A1 |
Schabel, Stefan ; et
al. |
September 5, 2002 |
Bag welding method and assembly for a bag filling station
Abstract
A bag welding method and assembly includes an upper jaw movable
in a substantially vertical plane and a lower jaw movable in the
same substantially vertical plane as the upper jaw and supported on
the frame via two support members. A pressure sensor is coupled to
the jaws for measuring a welding pressure between the jaws. A
processor coupled to the pressure sensor receives a signal from the
pressure sensor to determine the conditions under which the weld
was created. Preferably, the pressure sensor is mounted on one of
the support members, or alternatively, can be mounted in a recess
in one of the upper and the lower jaws. The welding assembly also
preferably includes a temperature sensor for measuring the
temperature between the welding jaws during sealing. The welding
assembly can also include a timer for determining the length of
time in which the welding jaws seal the bag.
Inventors: |
Schabel, Stefan; (Green Bay,
WI) ; Parsons, Ronald R.; (Oconto Falls, WI) |
Correspondence
Address: |
Derek C. Stettner
Michael Best & Friedrich LLP
100 East Wisconsin Avenue
Milwaukee
WI
53202-4108
US
|
Assignee: |
OPTIMA Machinery
Corporation
Green Bay
WI
|
Family ID: |
25178045 |
Appl. No.: |
09/800308 |
Filed: |
March 2, 2001 |
Current U.S.
Class: |
53/469 ; 53/570;
53/75 |
Current CPC
Class: |
B65B 2051/105 20130101;
B65B 43/465 20130101 |
Class at
Publication: |
53/469 ; 53/75;
53/570 |
International
Class: |
B65B 043/26; B65B
057/00 |
Claims
1. A device for filling and sealing bags, the device comprising: a
frame; a loading station within the frame; a welding assembly
coupled to the frame and adjacent the loading station for sealing
an open end of a bag after a package has been loaded into the bag,
the welding assembly including an upper welding jaw and a lower
welding jaw, wherein at least one of the upper and the lower
welding jaws is movably coupled to the frame via at least one
support member; and a pressure measurement device coupled to the
welding assembly for measuring the pressure between the upper and
the lower welding jaws when the bag is being sealed.
2. The device of claim 1, wherein the pressure measurement device
is mounted on the at least one support member.
3. The device of claim 1, wherein the pressure measurement device
is a load cell.
4. The device of claim 1, further including a processor that
processes a signal sent from the pressure measurement device to
analyze the quality of the seal.
5. The device of claim 1, wherein the lower welding jaw is movably
coupled to the frame via two support members that are capable of
moving the lower jaw into welding engagement with the upper welding
jaw, and wherein a pressure measurement device is mounted on each
of the support members.
6. The device of claim 5, further including a processor that
processes signals sent from each of the pressure measurement
devices to analyze the quality of the seal.
7. The device of claim 1, wherein the pressure measurement device
is mounted in a recess in one of the upper and the lower welding
jaws.
8. The device of claim 1, further including a temperature sensor
coupled to the welding assembly for measuring the temperature
during sealing.
9. The device of claim 1, further including a timer coupled to the
welding assembly for determining the length of time in which the
welding jaws seal the bag.
10. A device for filling and sealing bags, the device comprising: a
frame; a loading station within the frame; a package loading
assembly coupled to the frame and adjacent the loading station; a
bag loading assembly coupled to the frame and adjacent the loading
station, the bag loading assembly being operable to load an open
end of a bag into the loading station; a bag manipulating assembly
coupled to the frame to facilitate opening the bag; a welding
assembly coupled to the frame for sealing the open end of the bag,
the welding assembly including upper and lower welding jaws; and a
pressure measurement device coupled to the welding assembly for
measuring the pressure between the upper and lower welding jaws
when the bag is being sealed.
11. The device of claim 10, further including a temperature sensor
coupled to the welding assembly for measuring the temperature
during sealing.
12. The device of claim 10, further including a timer coupled to
the welding assembly for determining the length of time in which
the welding jaws seal the bag.
13. A method of packaging an item in a bag using an automated
packaging device, the method comprising: loading an open end of a
bag into a loading station; loading the item into the bag;
providing a welding assembly having an upper welding jaw and a
lower welding jaw, at least one of the upper and the lower welding
jaws being movably coupled to the frame via at least one support
member, and a pressure measurement device mounted on the at least
one support member for measuring the pressure between the upper and
the lower welding jaws when the bag is being sealed; sealing the
open end of the bag between the welding jaws after the item has
been loaded into the bag; measuring a sealing pressure with the
pressure measurement device; and sending a pressure signal to a
processor to determine conditions under which the seal was
created.
14. The method of claim 13, wherein the lower welding jaw is
movably coupled to the frame via two support members that are
capable of moving the lower welding jaw into welding engagement
with the upper welding jaw, wherein a pressure measurement device
is mounted on each of the support members, and wherein a pressure
signal from each of the pressure measurement devices is sent to the
processor to determine conditions under which the seal was
created.
15. The method of claim 14, wherein the support members are
oriented substantially vertically during sealing.
16. The method of claim 13, further including measuring a sealing
temperature with a temperature sensor.
17. The method of claim 13, further including providing a
predetermined sealing time in which the bag is sealed.
18. A welding assembly for a bag filling device, the welding
assembly comprising: an upper jaw movable in a substantially
vertical plane; a lower jaw movable in the same substantially
vertical plane as the upper jaw and supported on the frame via two
support members; a pressure sensor coupled to the jaws for
measuring a welding pressure between the jaws; and a processor
coupled to the pressure sensor to receive a signal from the
pressure sensor and to determine conditions under which the weld
was created.
19. The welding assembly of claim 18, wherein the pressure sensor
is mounted on one of the support members.
20. The welding assembly of claim 18, wherein the pressure sensor
is mounted in a recess in one of the upper and the lower jaws.
21. A method of sealing a bag, the method comprising: positioning a
bag between upper and lower jaws; moving the jaws together in a
substantially vertical plane to seal the bag; sensing a pressure
between the jaws when the jaws are together; sending pressure
measurements to a processor; and determining the quality of the
seal by analyzing whether the pressure measurements fall within a
predetermined set of allowable limits.
22. The method of claim 21, wherein sensing the pressure between
the jaws includes positioning a pressure sensor on a support member
coupled to one of the upper and the lower jaws.
23. The method of claim 22, wherein the support member is
substantially vertical when the jaws are together.
24. The method of claim 21, wherein sensing the pressure between
the jaws includes positioning a pressure sensor in a recess in one
of the upper and the lower jaws.
25. The method of claim 21, further comprising: sensing a
temperature between the jaws when the jaws are together; sending
temperature measurements to the processor; and determining the
quality of the seal by analyzing whether the temperature
measurements fall within a predetermined set of allowable limits.
Description
FIELD OF THE INVENTION
[0001] The invention relates to devices for opening, filling, and
sealing plastic bags and other packaging. More particularly, the
invention relates to automated devices that can produce an
air-tight seal when packaging bulky products.
BACKGROUND OF THE INVENTION
[0002] Bag opening and filling devices have been developed for a
wide variety of applications. Typically, these devices include one
or more mechanisms for selecting a single bag from a stack of
flattened, usually folded bags, and holding the selected bag open
for filling. Prior-art devices commonly include a wicket that holds
a stack of bags to be filled. Bags are torn from the wicket and
opened prior to filling. Once the bag is opened, a pusher mechanism
loads the product into the bag and a sealing mechanism seals the
bag after the product has been loaded.
[0003] In modern packaging applications many different types of
products are loaded into bags. It is difficult to obtain an
air-tight or hermetic seal using available automated sealing
equipment when packaging bulky products, such as diapers, sanitary
napkins, paper napkins, and similar products. Fortunately, it is
unnecessary to package these types of products in air-tight bags.
However, there are applications that require hermetic sealing of
the bag.
[0004] Packaging medical supplies is one such application. Hermetic
sealing is required to ensure that the medical supplies are not
contaminated after they are packaged and sealed in the bags.
Attempts to automate the packaging and sealing of bulky medical
supplies have been unsuccessful due to the problems associated with
placing a bulky object in a flat bag and then attempting to bring
the open edges of the bag together for sealing. The open edges
wrinkle, which prevents the formation of a proper seal along the
entire length of the bag opening. Consequently, bulky medical
supplies are packaged and sealed by hand to ensure that a hermetic
seal is produced. Manual packaging and sealing has several
deficiencies. It is cumbersome, time-consuming, and vulnerable to
human error.
SUMMARY OF THE INVENTION
[0005] Thus, there is a need for an automated packaging device that
can be used to package medical supplies and other products in bags
and to hermetically seal the bags. In addition, it would be
beneficial if such a machine could monitor the quality of the seal.
Further still, there is a need for a device where a relatively
large number of bags can be loaded or otherwise provided to the
packaging device so that product can be packaged at a relatively
high rate without the need for replenishing the supply of bags at a
similarly high rate.
[0006] In one embodiment, the invention provides an automated bag
filling station or packaging device capable of rapidly packaging
medical supplies and other bulky products in bags and sealing the
bags in an air-tight manner. The packaging device includes a
welding assembly for a bag filling device. The welding assembly
includes an upper jaw movable in a substantially vertical plane and
a lower jaw movable in the same substantially vertical plane as the
upper jaw and supported on the frame via two support members. The
welding assembly also includes a pressure sensor coupled to the
jaws for measuring a welding pressure between the jaws. A processor
coupled to the pressure sensor receives a signal from the pressure
sensor to determine the conditions under which the weld was
created.
[0007] In one aspect of the invention, the pressure sensor is
mounted on one of the support members. In another aspect of the
invention, the pressure sensor is mounted in a recess in one of the
upper and the lower jaws.
[0008] In yet another aspect of the invention, the welding assembly
includes a temperature sensor for measuring the temperature between
the welding jaws during sealing. The welding assembly also includes
a timer for determining the length of time in which the welding
jaws seal the bag.
[0009] In another embodiment, the invention provides a method of
sealing a bag. The method includes positioning a bag between upper
and lower jaws and moving the jaws together in a substantially
vertical plane to seal the bag. The method further includes sensing
a pressure between the jaws when the jaws are together and sending
pressure measurements to a processor. The processor then determines
the quality of the seal by analyzing whether the pressure
measurements fall within a predetermined set of allowable
limits.
[0010] In one aspect of the invention, sensing the pressure
includes positioning a pressure sensor on a support member coupled
to one of the upper and the lower jaws. Additionally, a second
pressure sensor can be positioned on a second support member.
Preferably, the support members are substantially vertical when the
jaws are together to obtain accurate pressure measurements. In
another aspect of the invention, sensing the pressure between the
jaws includes positioning a pressure sensor in a recess in one of
the upper and the lower jaws.
[0011] In yet another aspect of the invention, the method further
includes sensing a temperature between the jaws when the jaws are
together and sending temperature measurements to the processor to
determine the quality of the seal by analyzing whether the
temperature measurements fall within a predetermined set of
allowable limits.
[0012] Other features and advantages of the invention will become
apparent to those skilled in the art upon review of the following
detailed description, claims, and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view of an automated packaging device
embodying the invention.
[0014] FIGS. 1a and 1b are top views of the package loading
assembly in various operating states.
[0015] FIG. 2 is an enlarged side view showing one of the support
members of FIG. 1 in the package sealing position.
[0016] FIG. 3 is an enlarged side view showing the bag loading
assembly of the device of FIG. 1.
[0017] FIGS. 4-6 are side views of the conveyor assembly portion of
the bag loading assembly of FIG. 3 shown in various operational
states.
[0018] FIG. 7 is a partially cut away view of the conveyor assembly
taken along line 7-7 in FIG. 4.
[0019] FIG. 8 is a front view showing a loading station, a bag
manipulating assembly, and a bag welding assembly of the device of
FIG. 1.
[0020] FIG. 9 is an enlarged front view of the loading station and
the bag manipulating assembly shown with a bag opened for receiving
a package.
[0021] FIG. 10 is a perspective view of the loading station, the
bag manipulating assembly, and a portion of a bag loading assembly
loading a package into the opened bag.
[0022] FIG. 11 is an alternative gripper arrangement that can be
used with the bag manipulating assembly.
[0023] FIG. 12 is a sectional view of the welding jaws showing an
alternative pressure sensor configuration.
[0024] FIGS. 13-20 sequentially illustrate, in cross-section from
the side, the opening, closing, and sealing of the bag.
[0025] FIGS. 21-28 sequentially illustrate, from the front, the
opening, closing, and sealing of the bag.
[0026] FIG. 29 is a sealed bag containing a package.
[0027] FIGS. 30-32 illustrate an alternative spreader plate
arrangement for the bag manipulating assembly.
[0028] Before the invention is explained in detail, it is to be
understood that the invention is not limited in its application to
the details of construction and the arrangements of the components
set forth in the following description or illustrated in the
drawings. The invention is capable of multiple embodiments and of
being practiced or being carried out in various ways. Also, it is
understood that the phraseology and terminology used herein is for
the purpose of description and should not be regarded as limiting.
The use of"including" and "comprising" and variations thereof
herein is meant to encompass the items listed thereafter and
equivalents thereof as well as additional items.
DETAILED DESCRIPTION
[0029] A bag filling station 50 of one embodiment is shown in FIG.
1. The bag filling station 50 includes a frame 54 (only partially
shown) that supports the bag filling station 50. The frame 54 can
also support protective walls (not shown) positioned around the bag
filling station 50, as is commonly understood.
[0030] The bag filling station 50 includes a loading station 58
positioned within the frame 54, a package loading assembly 62
coupled to the frame 54 adjacent the loading station 58, a bag
loading assembly 66 coupled to the frame 54 adjacent the loading
station 58, a bag manipulating assembly 70 coupled to the frame 54
adjacent the loading station 58, and a bag welding assembly 74 (see
FIG. 8) coupled to the frame 54 adjacent the loading station 58.
For purposes of description only, the bag filling station 50 can be
defined in terms of a front 78, adjacent the package loading
assembly 62, a rear 82 adjacent the bag loading assembly 66, a
right side 86, and a left side 90 (see FIG. 8). A longitudinal axis
94 (see FIGS. 1, 1a, 1b, 9, and 10) extends from the front 78 to
the rear 82 through the loading station 58.
[0031] As seen in FIGS. 1, 1a, 1b, and 10, the package loading
assembly 62 includes a package conveyor assembly 98 capable of
transporting packages 102 to the loading station 58. The package
conveyor assembly 98 includes a conveyor table 106 supported by
support legs 110 (see FIG. 1). The conveyor table 106 includes an
endless conveyor belt 114 (see FIG. 10) driven by a drive device
118 (see FIG. 1). A suitable conveyor table 106 is available from
Dorner Manufacturing of Hartland, Wis. The drive device 118 can be
any suitable device capable of moving the conveyor belt 114, such
as an electric motor.
[0032] The package conveyor assembly 98 also includes a pair of
pusher arm assemblies 122 movably coupled to the conveyor table
106. The pusher arm assemblies 122 are substantially identical, and
only one will be described. As seen in FIG. 1, the pusher arm
assembly 122 includes a slide 126 mounted on a support member 130
for reciprocating linear movement in the direction of the
longitudinal axis 94. The linear movement of the pusher arm
assembly 122 is driven by any linear actuator (not shown) such as a
hydraulic or pneumatic actuator, a rack and pinion system, and the
like, or can be driven by the drive device 118.
[0033] The pusher arm assembly 122 also includes a pusher arm 134
having a pushing end 138 for pushing a package 102 into the loading
station 58. As best seen in FIG. 1a, the pusher arm 134 is movable
between a retracted position P.sub.R (shown in solid lines in FIG.
1a), where a package 102 can be advanced on the conveyor table 106
between the two pusher arms 134 toward the loading station 58, and
an extended position P.sub.E (shown in phantom lines in FIG. 1a),
where the two pusher arms 134 overlie the conveyor table 106. As
shown in FIG. 1b, when in the extended position, the pusher arms
move linearly from the position P.sub.1 (shown in solid lines in
FIG. 1b), to the position P.sub.2 (shown in phantom lines in FIG.
1b) so that the pushing ends 138 can push the package 102 into the
loading station 58.
[0034] Any suitable method of causing the movement of the pusher
arms 134 between the retracted and extended positions can be used,
including hydraulic or pneumatic actuators, rack and pinion
systems, and the like. While the package conveyor assembly 98
preferably includes two pusher arm assemblies 122, it is understood
that only one pusher arm assembly 122 could be used. Pusher arm
assemblies having other configurations are also contemplated,
including those shown in U.S. Pat. No. 5,799,465 incorporated by
reference herein.
[0035] The package conveyor assembly 98 also preferably includes a
sensor 142 (see FIG. 1) that senses the presence of a package 102
on the conveyor table 106 when the package 102 is adjacent the
loading station 58. The sensor 142, which can be in the form of an
optical sensor, a limit switch, or the like, communicates with the
pusher arm assemblies 122 so that the pusher arm assemblies 122 are
activated to push the package 102 when the package 102 is in
position adjacent the loading station 58.
[0036] The package conveyor assembly 98 can also include guide
rails 144 (see FIGS. 1a and 1b) on either side of the conveyor
table 106 extending substantially parallel to the longitudinal axis
94 to help guide the package 102. The guide rails 144 can be
adjustable to accommodate packages 102 of varying heights and
widths.
[0037] As seen in FIGS. 1 and 3-7, the bag loading assembly 66
includes a bag feeder or bag conveyor assembly 146 capable of
transporting a bag 150 to the loading station 58 for receiving a
package 102. The bags have an open end for receiving the package
102. The bag conveyor assembly 146 includes a conveyor assembly 154
supported by support legs 158. As best seen in FIGS. 3-7, the
conveyor assembly 154 includes a conveyor table 160 comprised of a
body portion 162, a drive roller 166, a follower roller 170, a pair
of tensioner rollers 174, an endless conveyor belt 178 encircling
portions of the body portion 162 and the rollers 166, 170, and 174,
and side supports 180 (only one is shown in FIG. 3).
[0038] The body portion 162 includes an upper cavity 182 and a
lower cavity 186 separated by a wall 190. The wall 190 separates
the cavities 182, 186 such that there is substantially no fluid
communication between the cavities 182, 186. Upper and lower inlet
ports 194 and 198, respectively (see FIG. 3), provide fluid
communication to the cavities 182, 186 as will be described below.
The body portion 162 further includes a top surface 202 having
elongated apertures 206 communicating between the top surface 202
and the upper cavity 182. The body portion 162 also includes a
bottom surface 210 having elongated apertures 214 that are
substantially identical to the apertures 206 and that communicate
between the bottom surface 210 and the lower cavity 186. The body
portion 162 has an overall width W (see FIG. 7).
[0039] Vacuum from a vacuum generator 218 (see FIG. 1) is applied
to the body portion 162 through separate supply hoses 222 and 223.
The upper supply hose 222 provides vacuum to the upper cavity 182
through the upper inlet port 194. The lower supply hose 223
provides vacuum to the lower cavity 186 through the lower inlet
port 198. Of course, two separate vacuum generators could be
used.
[0040] The elongated apertures 206, 214 supply vacuum to the
respective top and bottom surfaces 202, 210 over a working width W'
(see FIG. 7). The working width W' of vacuum at the top and bottom
surfaces 202, 210 is adjustable to accommodate the width of the
bags 150 being used. In one embodiment, as shown in FIG. 7, a
working width adjustment mechanism 226 is used to selectively block
and unblock all or portions of some of the apertures 206, 214. To
accomplish this, a pair of slide plates 230 (only the top slide
plate is shown in FIG. 7) is moved to block and unblock the
apertures, 206, 214. The slide plates 230 can be actuated manually
or automatically.
[0041] The drive roller 166 is spaced from one end of the body
portion 162, preferably in the rearward direction, and is supported
for rotation between the side supports 180. A drive device 234
drives the drive roller 166. In one embodiment, the drive device
234 is an electric motor, and more preferably an electric motor
that is programmed to actuate the drive roller 166 through a
predetermined number of revolutions in either direction as will be
described below. Alternatively, a standard electric motor could be
used in conjunction with a sensing device (not shown) such as an
optical sensor, a limit switch, or the like.
[0042] The follower roller 170 is spaced from the end of the body
portion 162 opposite the drive roller 166, and is also supported
for rotation between the side supports 180. The follower roller 170
preferably includes a cavity 238 that communicates with apertures
242 formed in the surface of the follower roller 170. A vacuum is
applied to the follower roller 170 as shown schematically in FIG.
7. The vacuum generator 218 or a separate vacuum generator (not
shown) is used to supply vacuum to the follower roller 170. It
should be understood, however, that the follower roller 170 need
not be configured to provide vacuum.
[0043] The endless conveyor belt 178 encircles the rollers 166, 170
such that there is always a portion of the conveyor belt 178
engaging both the top surface 202 and the bottom surface 210. The
tensioner rollers 174 are supported for rotation between the side
supports 180 as shown in FIG. 3, and at least one of the tensioner
rollers 174 is movable to adjust the tension in the conveyor belt
178 as is understood. Of course other arrangements can be used to
adjust the tension of the conveyor belt 178.
[0044] As seen in FIG. 7, the conveyor belt 178 includes a
plurality of transverse apertures 246 that provide communication
between the outer surface of the conveyor belt 178 and the
respective top and bottom surfaces 202, 210 so that the vacuum
supplied from the vacuum generator 218 to the body portion 162 can
communicate with the outer surface of the conveyor belt 178. In the
illustrated embodiment, each transverse aperture 246 communicates
with two apertures 206 when adjacent the top surface 202 and two
apertures 214 when adjacent the bottom surface 210. The transverse
apertures 246 also communicate with the apertures 242 in the
follower roller 170 so that a vacuum is also applied to the outer
surface of the conveyor belt 178 as the conveyor belt 178 passes
over the follower roller 170.
[0045] Although it is preferable to use vacuum, the conveyor table
160 need not be configured to supply vacuum to the conveyor belt
178. Rather, the conveyor table 160 could use other suitable
techniques, such as static attraction, to engage and manipulate the
bags 150 in the manner discussed below.
[0046] The conveyor table 160 is pivotable about the axis of
rotation of the drive roller 166 between a first, substantially
horizontal position P.sub.H (as shown in solid lines in FIGS. 1 and
3), and a second, inclined position P.sub.I (as shown in phantom
lines in FIGS. 1 and 3). The purpose of this movement will be
described below. A drive device 250 (see FIG. 1) is connected via
linkage members 254 to one or both of the side supports 180
adjacent the follower roller 170 as shown. Activation of the drive
device 250 moves the linkage members 254 to move the conveyor table
160 between the first and second positions P.sub.H, P.sub.I. Of
course, other methods of moving the conveyor table 160 between the
first and second positions, such as the use of actuators, rack and
pinion systems, and the like, are also contemplated.
[0047] As best seen in FIGS. 1 and 3, the bag conveyor assembly 146
also includes a bag holder or cartridge tray assembly 258
underneath the conveyor table 160 for holding a stack of bags 150.
A bag tray 262 is supported by the support legs 158 and receives a
stack of bags 150 which are positioned between guide walls 266
(only two are shown in FIGS. 1 and 3). To facilitate replacing the
stack of bags 150 in the bag tray 262, the bag tray 262 is
preferably mounted on rollers 270 (see FIG. 3) and can be rolled
out from underneath the conveyor table 160.
[0048] As best seen in FIG. 3, a lifting plate 274 inside the bag
tray 262 is connected to a lifting mechanism 278 that is fixed to
one of the support legs 158. The lifting mechanism can be an
actuator, a rack and pinion system, or the like. As will be
described below, the lifting mechanism 278 is actuated to move the
lifting plate 274 to raise or lower the stack of bags 150 with
respect to the bottom of the bag tray 262.
[0049] The conveyor assembly 154 can also include a take-off
conveyor 282 (see FIGS. 3-7) for receiving filled bags 150 as they
exit the conveyor table 160. The take-off conveyor 282 acts as a
bridge between the conveyor table 160 and a permanent conveyor (not
shown) that transports the filled bags 150 to an off-loading point.
Of course, the take-off conveyor 282 can be eliminated if the
permanent conveyor is arranged adjacent the drive roller 166 of the
conveyor table 160.
[0050] The loading station 58 is positioned between the package
loading assembly 62 and the bag loading assembly 66 and is best
seen in FIGS. 1 and 8-10. The frame 54 includes a substantially
rectangular support section 286 (see FIGS. 1 and 8) which
substantially surrounds the loading station 58 and which supports
the bag manipulating assembly 70 and the bag welding assembly 74.
Upper and lower transverse shafts 290 and 294, respectively, are
supported for rotation by the support section 286 and are coupled
together via linkages 298. A drive device 302 (see FIG. 8) is
coupled to the lower shaft 294 and selectively rotates the lower
shaft 294 in either direction. When the lower shaft 294 is rotated,
the linkages 298 cause rotation of the upper shaft 290.
[0051] A pair of upper support members or struts 306 are mounted to
the upper shaft 290 and connect the upper shaft 290 to an upper jaw
support member 310 (see FIG. 8). The upper jaw support member 310
is movably supported on substantially vertical guide rails 314
within the frame support section 286. Rotation of the upper shaft
290 causes vertical movement of the upperjaw support member 310, as
will be described below.
[0052] Likewise, a pair of lower support members or struts 318 are
mounted on the lower shaft 294 and connect the lower shaft 294 to a
lower jaw support member 322. The lower jaw support member 322 is
movably supported on the guide rails 314. Rotation of the lower
shaft 294 causes vertical movement of the lower jaw support member
322, as will be described below. Each of the lower struts 318 has
mounted thereon a pressure measurement device or sensor 324. The
pressure sensor 324 is preferably a load cell. For reasons to be
explained in more detail below, the lower struts 318 are sized so
that as the lower jaw support member 322 reaches its uppermost
vertical limit, the struts 318 are oriented substantially
vertically as shown in FIG. 2. If the range of motion of the lower
jaw support member 322 is varied for different applications, the
struts 318 can be adjusted so that the struts 318 will always be
substantially vertical when the lower jaw support member 322
reaches the uppermost vertical limit.
[0053] The upper and lower jaw support members 310, 322 support
portions of the bag manipulating assembly 70 and the bag welding
assembly 74. As best seen in FIG. 9, the lower jaw support member
322 supports a lower welding jaw 326, which will be described in
more detail below. A plurality of suction cup assemblies 330 are
mounted in spaced relation on a front face of the lower welding jaw
326. Each suction cup assembly 330 is connected to a vacuum supply
and can selectively apply suction via a suction cup 334. As will be
described below, the suction cup assemblies 330 are used to engage
an open end of the bag 150.
[0054] A pair of rotary actuators 338 are also mounted on the lower
jaw support member 322. Each rotary actuator includes a pin 342
that can be both rotated and translated with respect to the housing
of the rotary actuator 338, as is understood. A spreader plate 346
is mounted on the pin 342 of each rotary actuator 338. The purpose
of the spreader plate 346 will be described below. Together, the
suction cup assemblies 330, the rotary actuators 338, and the
spreader plates 346 define a lower bag spreader assembly 348.
[0055] The upper jaw support member 310 supports an upper welding
jaw 350 and a substantially identical upper bag spreader assembly
352 in opposing relation to the lower bag spreader assembly 348.
The upper bag spreader assembly 352 includes suction cup assemblies
354 having suction cups 358, and a pair of rotary actuators 362.
Each rotary actuator 362 has a pin 366 and a spreader plate 370
mounted on the pin 366.
[0056] Additionally, the upper jaw support member 310 includes a
pair of cam members 374 adjustably mounted to mounting plates 378.
The cam members 374 are substantially identical and only one will
be described. Each cam member 374 is fastened to one mounting plate
378 via upper and lower fasteners 382 and 383. The upper fastener
382 is received in a slot 386 in the cam member 374 such that the
cam member 374 is pivotally adjustable about the lower fastener
383. The cam member 374 further includes a cam surface 390
corresponding to an edge of the cam member 374. Adjustment of the
cam member 374 changes the angle of the cam surface 390. The cam
surface 390 can include an optional dwell point 394 (shown in
phantom in FIG. 9), which will be described below.
[0057] The cam members 374 cooperate with another portion of the
bag manipulating assembly 70. As best seen in FIGS. 8 and 9, a
support beam 398 is fixedly supported between the guide rails 314.
Unlike the upper and lower jaw support members 310, 322, the
support beam 398 is not free to move vertically along the guide
rails 314. A pair of gripper arm assemblies 402 (see FIG. 9) are
mounted on the support beam 398 in spaced-apart, opposing relation.
The gripper arm assemblies 402 are substantially identical, and
only one will be described in detail.
[0058] Each gripper arm assembly 402 includes a bracket member 406
having a base portion 410 and an arm portion 414. A gripper arm 418
is pivotally connected to the base portion 410 at pivot point 422.
A cam follower 426 is mounted to the gripper arm 418 and engages
the cam surface 390. In the illustrated embodiment, the cam
follower 426 is a roller. A linear actuator or gripper 430 is
mounted on the end of the gripper arm 418 for gripping the side
edges of a bag 150, as will be described below. The gripper 430 is
preferably a pneumatically-actuated, parallel gripper.
[0059] With continuing reference to FIG. 9, as the upper jaw
support member 310 moves downwardly, the cam followers 426 roll on
the cam surfaces 390 and the gripper arms 418 pivot about the pivot
points 422 in a plane substantially normal to the longitudinal axis
94. Downward movement of the upper jaw support member 310 causes
the gripper arms 418 and the grippers 430, to move away from one
another. As the upper jaw support member 310 moves upwardly, the
gripper arms 418 and the grippers 430 move back toward each other
in a plane substantially normal to the longitudinal axis 94. The
dwell points 394 in the cam surfaces 390 are designed to change the
cam surfaces 390 so that the pivot arms 418 will not pivot during
certain points of the operation of the bag filling station 50, as
will be described below.
[0060] On both gripper arm assemblies 402, a linear actuator 434 is
connected between the arm portion 414 and the gripper arm 418.
Together, the linear actuators 434 are operable to pivot the
gripper arms 418 even further away from one another than would
otherwise occur via the normal movement of the cam followers 426
along the cam surfaces 390. The linear actuators 434 are preferably
short-stroke pneumatic actuators. As will be described below, the
linear actuators 434 are preferably actuated just prior to the
sealing of the bag 150 when the upper jaw support member 310 is at
its lowermost vertical limit.
[0061] FIG. 11 illustrates a pair of alternative gripper assemblies
438 that can be used in place of the gripper arm assemblies 402.
Instead of the cam action used to pivot the gripper arm assemblies
402, the alternative gripper assemblies 438 are fixedly mounted to
the opposing vertical members of the frame support section 286, and
are linearly actuated to move the grippers 430 toward or away from
each other. The gripper assemblies 438 are substantially identical
and include back-to-back cylinders 442, 443 having respective rods
446, 447.
[0062] The rod 446 is connected to a sliding portion 450 which
slides on a guide rail 454. Actuation of the cylinder 442 moves the
rod 446 and causes movement of the sliding portion 450. The rod 447
is connected to a body portion 456 that is fixed with respect to
the frame support section 286. Actuation of the cylinder 443 causes
the cylinders 442 and 443 to move with respect to the body portion
456, thereby causing movement of the sliding portion 450. The
gripper 430 is mounted on the sliding portion 450 so that actuation
of either of the cylinders 442, 443 causes the grippers 430 to move
toward or away from one another.
[0063] The components of the bag manipulating assembly 70 operate
to receive the bag 150 from the bag loading assembly 66, open the
open end of a bag 150 so that the package 102 can be inserted, and
close the open end of the bag 150 once the package 102 has been
inserted. The bag 150 is closed in a manner that is conducive to
obtaining a quality seal of the open end of the bag 150. The bag
150 is under the control of the bag manipulating assembly 70 from
the time it is received to the time it is removed from the loading
station 58.
[0064] The bag welding assembly 74 is used to weld or seal the open
end of the bag 150 after the package 102 has been inserted. The
welding assembly 74 includes the upper and lower welding jaws 350,
326 and the associated hardware which are available from TOSS
Machine Components Inc. of Nazareth, Pa. As seen in FIG. 13, in one
embodiment, each of the welding jaws 326, 350 includes a body
portion 458, a fiberglass strip 462, a silicon strip 466, a teflon
strip 470, and a weld wire 474. A layer of teflon tape 478
surrounds the working ends of the welding jaws 326, 350. Of course,
welding could be accomplished with only one of the welding jaws
326, 350 having a weld wire 474.
[0065] The upper welding jaw 350 can also include a cutter assembly
482 that trims off a portion of the bag 150 after the open end has
been sealed. The cutter assembly 482 can include a knife edge 486
that extends to trim the bag 150 when the welding jaws 326, 350 are
closed. Of course, other cutter assembly configurations can be
used. For example, a welding jaw having a sealing wire that
simultaneously seals and cuts the bag 150 could also be used.
[0066] The welding assembly 74 also includes the pressure
measurement devices 324 mounted on the lower struts 318. The
pressure measurement devices are used to measure the pressure
between the welding jaws 326, 350 while the bag 150 is sealed.
Recall that as the lower welding jaw 326 reaches its uppermost
vertical limit (i.e., the position where the welding takes place),
the lower struts 318 are substantially vertical. This orientation
promotes accurate measuring of the welding pressure because the
pressure measurement devices 324 are in axial alignment with the
forces exerted on the lower welding jaw 326 by the upper welding
jaw 350.
[0067] FIG. 12 illustrates an alternative arrangement for the
pressure measuring device. In FIG. 12, a pressure measurement
device 490 (i.e., a load cell or the like) is mounted in a recess
in the upper welding jaw 350. A contact disk 494 is mounted in a
recess in the lower welding jaw 326. Multiple sets of devices 490
and disks 494 can be spaced along the length of the welding jaws
326, 350 as desired.
[0068] Regardless of the pressure measuring arrangement used, the
pressure measuring devices 324, 490 are used to monitor the quality
of the seal that is created by the welding jaws 326, 350, as will
be described below. Verifying the formation of a quality seal
without human intervention, and being able to document and record
the process for future reference is an advantage of the bag filling
station 50. The bags 150 are sealed using heat to melt the open end
of the bag 150 together, as is understood. At least three
components are important to achieve a good seal: pressure,
temperature, and time. The bag filling station 50 monitors these
three components so that the quality of the seal can be validated,
which is especially important when packaging medical devices.
[0069] Time is the easiest to control, and refers to the time the
pressure and heat are applied during the sealing process.
Temperature is more difficult to control and measure, but suitable
products are available. Pressure is applied using the drive device
302, such as an electric motor. Controlling the pressure entails
controlling the current in the electric motor. Alternatively,
pressure could be controlled via an air-cylinder (not shown).
Pressure is measured using the pressure measurement devices 324, as
described below.
[0070] During the sealing process, the weld wires 474 are heated to
a temperature set by a controller or processor 502. The processor
502 is preferably a programmable logic control device and can have
a video display 506. The temperature is held for a predetermined
time dictated by the processor 502. The actual temperature of the
weld wires 474 is monitored and temperature signals are sent to the
processor 502 via signal lines 510. The actual temperature is
compared to predetermined temperature settings.
[0071] When the heat command is removed, the welding seam is
allowed to cool and pressure is applied for a time specified by the
processor 502. As seen in FIG. 8, the pressure measuring devices
324 are linked to the processor 502 via lines 512. The processor
502 analyzes the signals from the pressure measurement devices 324
and determines the actual welding pressure applied. In one
embodiment, the measured pressure, heat, and time values are
displayed on the video display 506 and are compared to a
predetermined values to determine the quality of the seal.
Additionally, two or more pressure measurements (corresponding to
the number of pressure measurement devices 324 or 490 used) are
compared to one another to determine the consistency of the seal
along the length of the welding jaws 326, 350. With this approach,
inconsistent or incomplete sealing caused by debris between the
welding jaws 326, 350 or wrinkles in the bag 150 can be
detected.
[0072] The processor 502 reads and records the pressure and
temperature data at a predetermined sampling rate that allows the
process to be validated. Each seal has data associated with it that
the seal was heated to a certain temperature and that a certain
pressure was maintained for a certain time. If any of the data
indicates that improper sealing conditions were present, the sealed
bag is rejected. While not shown, the bag filling station 50 can
also include a marking device that can be used to catalog the
sealed bags by placing some form of indicating feature (i.e., a
serial number, a bar code, or the like) on the bags that is linked
to the weld data. When the bags are marked with an indicating
feature, the seal quality of any bag can be verified at a later
time.
[0073] The operation of the bag filling station 50 will now be
described. The bags 150 are first stacked in the bag tray 262 so
that the open ends are to the right as viewed in FIG. 3. The bag
tray 262 is then slid into place underneath the conveyor table 160.
With the conveyor table 160 in the substantially horizontal first
position P.sub.H, the lifting mechanism 278 is actuated to lift the
stack of bags 150 toward the bottom surface 210 of the body portion
162. As seen in FIG. 4, when vacuum is applied to the lower cavity
186, the top bag 150 on the stack of bags is engaged by the
conveyor belt 178 due to the vacuum communication between the
apertures 214 and the transverse apertures 246. Once the top bag
150 is engaged with the conveyor belt 178, the lifting mechanism
278 is lowered to lower the stack of bags 150 away from the bottom
surface 210.
[0074] Next, the drive device 234 indexes the drive roller 166 such
that the bag 150 moves with the conveyor belt 178 as shown in FIG.
5. Vacuum is applied to the follower roller 170 to hold the bag 150
in engagement with the conveyor belt 178 as the bag 150 passes over
the follower roller 170. At approximately the same time, the drive
device 250 drives the linkage members 254 to move the conveyor
table 160 from the first position P.sub.H to the second, inclined
position P.sub.I. As the bag 150 approaches the top surface 202,
vacuum is applied to the upper cavity 182 to maintain the
engagement between the conveyor belt 178 and the bag 150. At about
the same time, the vacuum is turned off in the lower cavity 186.
Once the conveyor belt 178 has traveled a predetermined distance
(as gauged by the programmable motor or the sensing device), and
the bag 150 is on top of the conveyor table 160, the drive device
234 reverses direction to load the open end of the bag 150 into the
loading station 58 as shown in FIG. 6.
[0075] FIGS. 13-20 and 21-28 illustrate (from the side and the
front, respectively) the sequential operation of the bag
manipulating assembly 70 and the bag welding assembly 74 once the
bag 150 is loaded into the loading station 58. As seen in FIGS. 13
and 21, the bag is moved into the loading station 58 and the side
edges of the bag 150 pass through the open grippers 430. The open
end of the bag 150 is oriented substantially horizontally in the
loading station 58 as shown. The upper and lower welding jaws 350,
326 (and therefore the upper and lower bag spreader assemblies 348,
352) are slightly opened to provide clearance for the bag 150. In
this position, the cam followers 426 are positioned in or near the
dwell point 394.
[0076] Next, as seen in FIGS. 14 and 22, the grippers 430 close,
thereby securely clamping the opposing side edges of the bag 150 to
maintain control over the bag 150 at all times during the packaging
operation. Additionally, the welding jaws 326, 350 close so that
the suction cups 334, 358 approach the open end of the bag 150 from
both sides. Due to the presence of the dwell points 394, the
grippers 430 do not move toward each other as the jaws 326, 350
close. Vacuum is applied to the suction cups 334, 358 so that the
suction cups 334, 358 engage both sides of the open end of the bag
150.
[0077] As seen in FIGS. 15 and 23, the welding jaws 326, 350 then
open slightly. Because the suction cups 334, 358 have a suction
grip on the top and bottom of the open end of the bag 150, the bag
150 opens slightly in response to the opening of the welding jaws
326, 350. Again, due to the dwell point 394, the grippers 430 do
not move toward each other. The grippers 430 (shown schematically
in FIG. 15) remain closed to keep a secure grip on the side edges
of the bag 150.
[0078] Next, as seen in FIGS. 16 and 24, the rotary actuators 338,
362 are actuated so that the spreader plates 346, 370 rotate into
the open end of the bag 150. The pins 342, 366 of the rotary
actuators 338, 362 also retract to draw the spreader plates 346,
370 closer to the respective suction cups 334, 358. Meanwhile, the
suction is still being applied to the bag 150 by the suction cups
334, 358. The grippers 430 remain closed.
[0079] At this point, it is worth noting that other spreader plate
arrangements can also be used to open the bag. FIGS. 30-32
illustrate alternative upper and lower bag spreader assemblies 514
and 518, respectively. Instead of the rotary actuators 338, 362
having the rotating and translating spreader plates 346, 370, the
alternative upper and lower bag spreader assemblies 514 and 518
include respective upper and lower pivoting bag spreader plates 522
and 526. Respective actuators 530 and 534 cause the pivoting bag
spreader plates 522 and 526 to pivot into and out of the open end
of the bag 150 as is sequentially shown in FIGS. 31 and 32.
[0080] Returning to FIGS. 17 and 25, the welding jaws 326, 350 are
opened wider so that the open end of the bag 150 is opened widely
enough to receive a package 102. Both the suction cups 334, 358 and
the spreader plates 346, 370 aid in opening the bag 150. As best
seen in FIG. 9, when the upper welding jaw 350 is moved upwardly to
open the bag 150, the gripper arms 418 pivot inwardly toward each
other in response to movement of the cam members 374. The inward
pivoting of the gripper arms 418 moves the grippers 430 toward each
other and facilitates spreading the open end of the bag 150 apart.
The grippers 430 remain closed to hold the side edges of the bag
150.
[0081] Sometime before the package 102 is pushed into the bag 150,
the conveyor table 160 of the bag loading assembly 66 is returned
to the first, substantially horizontal position P.sub.H (see FIGS.
1 and 4) so that the package 102 can be pushed into the bag 150
without being obstructed by the follower roller 170. Returning the
conveyor table 160 to the horizontal position also prepares the bag
loading assembly 66 for picking up the next bag 150 from the
stack.
[0082] At this point, the bag 150 is ready to receive a package
102. The package 102 is placed on the conveyor table 106 (see FIG.
1) and the drive device 118 drives the conveyor belt 114 to move
the package 102 toward the loading station 58. The pusher arms 134
are in the retracted position P.sub.R (see FIG. 1a) to allow the
package 102 to pass by. When the sensor 142 detects the package
102, the conveyor belt 114 stops and the pusher arms 134 move to
the extended position P.sub.E to overlie the conveyor table 106.
The pusher arm assemblies 122 then move linearly toward the waiting
package 102 so that the pushing ends 138 engage the package 102
(see FIGS. 1b and 10) and push the package 102 into the bag 150
(see FIGS. 18 and 26). The pusher arms 134 are then withdrawn from
the bag 150 and returned to the retracted position P.sub.R in
anticipation of the next packaging cycle.
[0083] With the package 102 inside the bag 150, the bag 150 is
sealed. As seen in FIGS. 19 and 27, the welding jaws 326, 350 close
so that the open end of the bag 150 closes. Just prior to closing,
the spreader plates 346, 370 rotate out of the bag 150. The suction
is turned off at the suction cups 334, 358. As the upper welding
jaw 350 moves downwardly, the gripper arms 418 pivot outwardly,
away from each other. Since the grippers 430 are still closed on
the side edges of the bag 150, the outward movement of the gripper
arms 418 acts to stretch the bag 150, thereby helping to flatten
the open end of the bag 150 in preparation for sealing.
[0084] To ensure that the open end of the bag 150 closes
substantially without any wrinkling caused by the bulky package 150
inside the bag, the linear actuators 434 connected to the gripper
arms 418 (see FIGS. 8 and 9) pull the gripper arms 418 even further
outwardly, away from each other. This additional outward movement
of the grippers 430 stretches the side edges of the bag 150 apart
even further to completely flatten the open end of the bag 150 and
to substantially remove any wrinkles that could cause inconsistent
or incomplete sealing.
[0085] Electricity is applied to the weld wires 474 to heat seal
the open end of the bag 150, as is understood. The processor 502
monitors the weld temperature, pressure, and time as described
above to monitor the quality of the seal obtained.
[0086] Either during, or just after welding, the cutter assembly
482 is activated to trim the bag 150 as shown in FIG. 20. As shown
in FIG. 28, the trimmed bag pieces 538 are removed from the loading
station 58 using a vacuum tube 542. The vacuum tube 542 is a tube
positioned adjacent the loading station 58 where the trimmed bag
pieces 538 are located. Vacuum supplied to the vacuum tube 542
extracts the trimmed bag pieces 538 and deposits them in a waste
receptacle (not shown). Of course, other methods of removing the
trimmed bag pieces 538 can be used. Alternatively, the sealed bag
150 need not be trimmed at all.
[0087] With the bag 150 packed and sealed, the grippers 430 are
opened to release the side edges of the bag 150 and the conveyor
belt 178 is activated to move the sealed bag 150 out of the loading
station 58 and to the take-off conveyor 282 (see FIGS. 7 and 8). As
seen in FIGS. 7 and 8, the next packaging cycle is underway and the
next bag 150 from the stack is concurrently being engaged and moved
into the loading position by the conveyor belt 178.
[0088] While not shown in the figures, the follower roller 170 can
also be adapted to remove the air from inside the packed and sealed
bag 150 if vacuum packing is desired. Alternatively, vacuum packing
could occur at a later time on a different machine.
[0089] FIG. 29 illustrates a packed and sealed bag 150. The sealed
area extends across the width of the bag 150 and is generally
designated by the reference numeral 546.
[0090] Various features of the invention are set forth in the
following claims.
* * * * *