U.S. patent number 3,706,174 [Application Number 05/120,512] was granted by the patent office on 1972-12-19 for packaging machine and method of forming packages.
This patent grant is currently assigned to John Morrell & Co., W. R. Grace & Co.. Invention is credited to Arthur D. Jezuit, William E. Young.
United States Patent |
3,706,174 |
Young , et al. |
December 19, 1972 |
PACKAGING MACHINE AND METHOD OF FORMING PACKAGES
Abstract
A machine and method for evacuating sealed packages formed from
flexible sheet material which may be heat sealed, and for sealing
the package. A heat-sealing device has two sections disposed
opposite each other and movable toward each other to seal two
sheets of the flexible material together to form a sealed package.
One of the sections comprises a suction head for applying vacuum to
one of the sheets of flexible material to cause the one sheet to
move toward a knife member fixedly secured in the suction head to
form a pierced opening in the one sheet through which air is
exhausted from the package through the pierced opening. A
heat-sealing member is disposed in and reciprocable in the suction
head for movement between a retracted position and an extended
sealing position. The heat-sealing member is adapted to heat seal
the sheets together in an area surrounding the pierced opening when
in its extended position. In the preferred form of the invention,
the other section of the heat-sealing device also comprises a
vacuum head for applying suction to the other sheet of flexible
material to grip the other sheet while the one sheet is being
pierced and the air is evacuated from the package.
Inventors: |
Young; William E. (Stamford,
CT), Jezuit; Arthur D. (Wood Dale, IL) |
Assignee: |
W. R. Grace & Co. (Duncan,
SC)
John Morrell & Co. (Chicago, IL)
|
Family
ID: |
22390768 |
Appl.
No.: |
05/120,512 |
Filed: |
March 3, 1971 |
Current U.S.
Class: |
53/510 |
Current CPC
Class: |
B65B
31/08 (20130101); B65B 9/04 (20130101) |
Current International
Class: |
B65B
31/04 (20060101); B65B 31/08 (20060101); B65B
9/04 (20060101); B65B 9/00 (20060101); B65b
031/02 () |
Field of
Search: |
;53/22R,22A,22B,112R,112A,112B |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: McGehee; Travis S.
Claims
We claim:
1. An apparatus for evacuating a sealed package formed of two
opposite sheets of flexible material capable of being heat sealed
and for sealing said package, comprising: a frame, a heat-sealing
device carried by said frame and having two sections disposed
opposite each other and movable toward each other, one of said
sections constituting a suction head, the other of said sections
having a pair of wells for holding one sheet of said flexible
material with a load of product in each well and a partition
extending between said wells against which a portion of the
last-mentioned sheet engages, a knife means disposed in and
immovable relative to said suction head and overlying said
partition at a distance therefrom and adapted to pierce the other
of said sheets upon subjecting said other sheet to movement toward
the knife means by a suction effect from said suction head, vacuum
means connected with said suction head to apply suction thereto to
cause the other sheet to move toward said knife means to form a
pierced opening in said other sheet and to exhaust air from between
said sheets, vacuum means connected to the other of said sections
to hold said one sheet against the partition and prevent movement
and piercing thereof, and a heat-sealing member disposed in and
reciprocable in said suction head and overlying said partition for
movement between a retracted position and an extended sealing
position pressing both said sheets against said partition, said
heat-sealing member being adapted to heat seal said sheets in an
area surrounding said pierced opening when in said sealing
position.
2. The apparatus of claim 1 including resilient means for urging
said sealing member toward its retracted position.
3. The apparatus of claim 1 wherein said one section is fixed to
said frame and the other of said sections is movably mounted on the
frame for movement into sealing position with said one section.
4. The apparatus of claim 1 wherein said heat-sealing member
surrounds said knife means and strips the other sheet from about
the knife while moving toward its extended sealing position.
5. The apparatus of claim 4 wherein said vacuum means applies
suction between said knife means and said sealing member.
6. The apparatus of claim 1 including control means to apply vacuum
to said other section prior to applying vacuum to said one
section.
7. An apparatus for sealing and evacuating a package formed from
two opposite sheets of heat sealable flexible material comprising,
a pair of relatively movable parts having means at their perimeter
for engaging and sealing the sheets together to form a perimeter
seal for the package, one of said parts constituting a sealing head
and the other part constituting a package-holding head, said
package-holding head having a support member against which a
portion of one sheet of said material engages, vacuum means
connected to said package-holding head for holding said package
against movement and said sheet portion against the support member
during evacuation of the package, said suction head having a
slitting knife overlying and spaced from said support member,
vacuum means connected to said suction head to draw a part of the
other sheet of material away from said one sheet and form an
evacuation opening therein and then evacuate the package through
said opening, and heat sealing means movable past the knife and
toward the support member to return said other sheet into
engagement with said one sheet and heat seal the sheets together by
pressure against said support member.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to a machine and method for evacuating
sealed packages having a flexible wrapper of which at least the
inner surface is heat sealable and for sealing the package.
Food products and other commodities are marketed in flexible sheet
material or film made of air and moisture impervious plastic, the
packages being formed either from precut sections of the flexible
material or from a continuous length thereof. Some of the products
so marketed are adversely affected by their exposure to air for a
length of time, but they retain their desired characteristics if
maintained in a package from which the air has been evacuated.
Various machines or procedures have been utilized to evacuate
packages of the character described after inserting into the
packages the food products or other commodities. In one type of
machine, the packages containing the products are fed to a vacuum
chamber, the chamber is sealed, and the air is evacuated from the
chamber. Upon arriving at the desired vacuum, the package which has
been subjected to the vacuum within the chamber is sealed off by
heat-sealing means. With such machines, a slit must be formed in
the package before the package is fed to the vacuum chamber, thus
creating adjustment problems for the slitter with different sizes
and shapes of packages.
In other types of machines the package is completely closed or
sealed after the products have been inserted therein, a hole is
punched through the package, and the air within the package is
evacuated through the punched hole. The area of the package
surrounding the hole then is sealed off, and the package thus is
maintained hermetically sealed.
Examples of machines of the last-mentioned type may be seen by
reference to the U.S. Pats. to Gebhardt Nos. 2,888,788 and
2,896,385. With the machine disclosed in these two patents, a hole
is punched through one sheet of the film which forms the package by
means of a knife disposed in a suction line, so that the punching
of the hole is brought about by a suction effect applied to the one
sheet of film. Not only are the two sections of the heating device
in said structures relatively movable to seal the package, but the
knife is mounted for axial movement in one of the sections which
forms a suction head at the end of a suction line. The knife must
be withdrawn into the suction head after piercing the one sheet of
film, resulting in a complicated machine, as well as one which is
difficult to control in respect to coordinating the sequence of
suction application and movement of the knife blade. It is a
solution for such problems that the present invention is
directed.
It is, therefore, one object of the present invention to provide a
new and improved apparatus of the character described for
evacuating a sealed package and for sealing the package.
Another object of the invention is to provide an apparatus for
evacuating a sealed package formed of two opposite sheets of
flexible material capable of being heat sealed and for sealing the
package, including a frame and a heat-sealing device carried by the
frame. The heat-sealing device has two sections disposed opposite
each other and movable toward each other to seal the two sheets,
one of the sections constituting a suction head. A knife means is
disposed in and immovable relative to the suction head, and is
adapted to pierce one of the sheets upon subjecting the one sheet
to a suction effect from the suction head. A vacuum means is
connected with the suction head to apply suction thereto to cause
the one sheet to move toward the knife means to form a pierced
opening in the one sheet and to exhaust air from between the sealed
sheets. A heat-sealing member is disposed in and reciprocable in
the suction head for movement between a retracted position and an
extended sealing position, the heat-sealing member being adapted to
heat seal the two sheets together in an area surrounding the
pierced opening after the air is evacuated. The heat-sealing member
surrounds the knife means and is resiliently urged toward its
retracted position.
In the preferred embodiment of the invention, the other section of
the heat-sealing device, referred to above, also comprises a
suction head, and vacuum means is connected with the other section
to apply suction thereto to grip the other sheet of flexible
material while the one sheet is being pierced and the air is being
evacuated from between the sheets. Control means is provided to
apply the vacuum to the other section of the heat-sealing device
prior to applying the vacuum to the first section, the vacuum to
both sections being released simultaneously after the sheets are
heat sealed in the area surrounding the pierced opening.
A further object of the invention is to provide a method of
evacuating a sealed package, as described herein.
Other objects, features and advantages of the invention will become
apparent from the following detailed description taken in
connection with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a packaging machine embodying the
concepts of the present invention;
FIG. 2 is a schematic elevational view illustrating the machine
part or station arrangement of the packaging machine shown in FIG.
1;
FIG. 3 is a partial plan view of the machine, on an enlarged scale,
taken generally along the line 3--3 of FIG. 1;
FIG. 4 is a vertical section taken generally along the line 4--4 of
FIG. 3;
FIG. 5 is a vertical section taken generally along the line 5--5 of
FIG. 4;
FIG. 6 is a vertical section, on an enlarged scale, taken generally
along the line 6--6 of FIG. 4;
FIG. 7 is a vertical section taken generally along the line 7--7 of
FIG. 6; and
FIGS. 8 through 11 are sequential schematic views of the sealing
and evacuating head, as seen in detail in FIG. 6, to facilitate an
understanding of the method of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings in greater detail, and first to FIGS. 1
and 2, a packaging machine, generally designated 15 in FIG. 1, is
shown and is designed to package food products or other commodities
in packages formed from flexible sheet material or film which is
capable of being heat sealed about the product. Referring to FIG.
2, one continuous film F' is stripped off of a lower supply roll 16
of heat-sealable flexible material and is carried successively to a
forming station 18 where individual pockets P or clusters thereof
are formed in the film for receiving a product to be packaged, then
to a loading station 20 where the product is loaded or positioned
in the pockets P, normally by hand, and then to a sealing and
evacuation station 22. A second continuous sheet or layer of film
F" is carried from an upper film supply roll 24 of heat-sealable
flexible material to a point between the loading station 20 and the
sealing and evacuating station 22, to overlie the lower film sheet
F' and the pockets P formed therein, with the product loaded in the
pockets. The juxtaposed lengths of film then are carried to the
sealing and evacuating station 22 where the sheets are heat sealed
together about the periphery of the pockets P and air is evacuated
from within the pockets to provide moisture and air impervious
packages. The sealed pockets then are carried to a cutter 26 where
the webs of film between the individual pockets are cut. The waste
film is carried from the cutting station by a vacuum nozzle 28, and
the severed filled and sealed packages are carried therefrom as by
a conveyor 30.
Should either the upper or lower sheets of film F" and F',
respectively, be printed along the length thereof for each package,
film registration means or stations 33 for the upper sheet of film
F" and 33' for the lower sheet of film F' may be provided to index
the film so that the printing thereon is properly aligned for each
ultimately sealed and loaded package.
The present invention deals primarily with a new and improved
apparatus at the sealing and evacuating station 22 for sealing the
upper and lower sheets of film together about each individual
loaded pocket P and for evacuating the air from within the sealed
pocket to provide an air and moisture impervious package.
Referring to FIGS. 3 through 7, the apparatus at the sealing and
evacuating station includes a heat-sealing device generally
designated 32 mounted on the frame of the machine 15 and having
upper and lower sections 32a and 32b, respectively. The two
sections 32a, 32b of the heat-sealing device are disposed opposite
each other, as best seen in FIGS. 6 and 7, and the lower section
32b is vertically reciprocable relative to the upper section 32a by
means shown in FIGS. 4 and 5 (described in greater detail
hereinafter).
The lower section 32b of the heat-sealing device 32, in the
embodiment of the invention illustrated in the drawings, has a pair
of wells 34 separated by a partition 36 for receiving a pair of
pockets P formed in the lower sheet of film F' at the forming
station 18. The pockets will have been loaded with the product at
the loading station 20 by the time they reach the heat-sealing
device. The lower section 32b is generally rectangular in shape and
has resilient insert members 38 about the upper peripheral edges
thereof about the wells 34 and resilient insert members 40 (FIG. 7)
in the partition 36 between the wells, the insert members 38, 40
being provided as backing members to facilitate heat sealing the
two sheets or layers of film together when the lower section 32b is
moved upwardly into engagement with the upper section 32a which
comprises a heating section, as described in greater detail
hereinafter.
The lower section 32b of the heat-sealing device 32 has interior
passages 42 in the base thereof communicating with the wells 34 at
the bottom thereof and in communication with a vacuum hose or
conduit 44 connected with an appropriate vacuum source for applying
suction to the lower sheet of film F' to grip the film during air
evacuation of the packages.
FIGS. 4 and 5 show the means for mounting the lower section 32b of
the heat-sealing device 32 for vertical reciprocating movement into
and out of engagement with the upper section 32a of the
heat-sealing device 32. The lower section 32b is journalled on
vertical guide shafts 46 which form part of mounting brackets 48
secured to side wall portions 50 of the frame of the packaging
machine 15. A linkage structure, generally designated 52, is
disposed between the lower section 32b of the heat-sealing device
and a bottom wall portion 54 of the frame of the packaging machine
15. The linkage structure has four link members 52a through 52d
which effect vertical movement of the lower section 32b in response
to rotation of a cam member 57 (FIG. 4). The link 52a is elongated,
is pivotally connected at one end thereof to the underside of the
lower section 32b, and is pivotally connected at the other end
thereof to one end of elongated link 52b. The other end of link 52b
is pivotally connected to the bottom wall portion 54 of the machine
frame. Link member 52c also is elongated, is pivotally connected at
one end thereof intermediate the ends of the link 52b, and is
pivotally connected at the other end thereof to link 52d which is
triangularly shaped. One corner of the triangularly-shaped link 52d
is connected to the link 52c, another corner thereof is pivotally
connected to the base wall portion 54, and the third corner thereof
has a roller member 55 positioned in a slot 56 of a cam member 57.
The cam slot 56 has a "rise" portion 56a and a "fall" portion 56b.
Thus, as the cam member 57 is rotated in the direction of arrow A,
for instance, the rise portion 56a of the cam slot 56 pivotally
cams the link 52d in the direction of arrow B (FIG. 4). The link
52d, through the link 52c, will cause the link 52b to pivot about
its connection to the base wall portion 54 in the direction of
arrow C. The link 52b in turn causes the lower end of link 52a to
move outwardly in the direction of arrow D to pull the lower
section 32b of the heat-sealing device 32 downwardly in the
direction of arrow E away from and out of engagement with the upper
section 32a. When the roller member 55 on the triangularly-shaped
link 52d moves back into the "fall" portion 56b of the cam slot 56,
as seen in FIG. 4, the links 52a-52d will be urged in directions
opposite that described above, causing the lower section 32b of the
heat-sealing device 32 to move into engagement with the upper
section 32a.
Referring particularly to FIGS. 6 and 7, the upper section 32a of
the heat-sealing device 32 comprises a heating and suction head to
effect a heat seal between the layers or sheets of film F', F"
about the pockets P formed therein, and for evacuating the air from
between the sealed sheets. More particularly, the upper section 32a
of the heat-sealing device 32 is fabricated of heat-conductive
material and has an electrical heating element 58 embedded therein
so as to distribute the heat from the heating element 58 through
the body of the upper section 32a. The heating element 58 is
connected through an electrical cable 59 (FIG. 6) through a conduit
59a to an appropriate electrical source. To facilitate a heat seal,
the upper section 32a has a downwardly depending lip 60 (FIG. 6)
about the periphery thereof and overlying the resilient insert
members 38 in the lower section 32b. The upper section 32a also has
downwardly depending lips which extend inwardly, as at 62 in FIG.
7, over the upper edge of the partition 36 of the lower section 32b
generally approximately one-fourth of the length of the partition
36 at each end thereof. The downwardly protruding lips 62 overlie
the resilient insert members 40 (FIG. 7) disposed in the partition
36 of the lower section 32b of the heat-sealing device. Thus, it
can be seen that as the rotatable cam 57 moves the lower section
32b upwardly toward the upper section 32a, the juxtaposed sheets of
film F' and F" will be sandwiched between the sections of the
heat-sealing device and will be heat sealed in the areas defined by
the lips 60, 62 of the upper section 32a and the resilient insert
members 38, 40 of the lower section 32b. Insulating plate members
65 are provided on the underside of the upper section 32a to
insulate the remaining areas of the upper sheet of film from the
heated body portion of the upper section.
A knife blade 66 is disposed in and immovable relative to the upper
section 32a of the heat-sealing device and is adapted to pierce the
upper sheet of film F" upon subjecting the upper sheet to a suction
effect from the upper section 32a, as described hereinafter. The
knife blade 66 is secured to a downwardly depending shaft 68
rigidly secured in an upper wall portion 70a of a sleeve 70 which
is rigidly mounted on an upper mounting block 72 of the
heat-sealing device. The sleeve 70 has a plurality of openings 70b
in communication with interior passage means 74 (FIG. 7) within the
mounting block 72. The passage means 74 in the mounting block leads
to a vacuum hose or conduit 76 which is connected to an appropriate
vacuum source. Appropriate seals 77 are provided about the sleeve
70 above and below the openings 70b and the passage means 74 to
prevent seepage of air when suction is applied. Thus, it can be
seen that as vacuum is applied to the hose 76, suction will be
created in the sleeve 70 and thereby subject the top sheet of film
F" within the upper section 32a to a suction effect. The suction
will cause the top sheet to move toward the knife 66 to form a
pierced opening in the top sheet F". Continued application of
suction will cause the air to be evacuated from between the sealed
sheets of film (i.e. from within the pockets P disposed within the
wells 34 of the lower section 32b of the heat-sealing device)
through the pierced opening in the top sheet of film. The evacuated
air passes around the knife blade 66 and through the openings 70b
into the passage means 74 in the mounting block 72.
Continuing to refer particularly to FIGS. 6 and 7, the piercing
knife blade 66 is surrounded by a heat-sealing member 78 disposed
in and reciprocable in the upper section 32a, the heat-sealing
member 78 being adapted to heat seal the sheets of film in an area
surrounding the opening pierced in the upper sheet of film after
the air is evacuated from between the sheets. More particularly,
the heat-sealing member 78 has an electrical heating element 80
embedded therein and the member 78 is fabricated of
heat-transferable material so as to dissipate the heat from the
heating element. The heating element 80 is connected through an
electrical cable 82 through a conduit 84 to an appropriate
electrical source. The heat-sealing member 78 is movable between a
retracted position shown in FIG. 7 to an extended sealing position
wherein the heat-sealing member moves downwardly in the direction
of arrows G to sandwich the sheets of film F', F" between the
heat-sealing member 78 and resilient insert members 79 (FIG. 6)
which are embedded in the partition 36 of the lower section 32b,
surrounding the piercing knife blade 66.
To effect vertical reciprocation of the heat-sealing member 78, a
pair of shafts 86 extend upwardly from the member 78 and are
journalled in sleeves 88 disposed in the mounting block 72. A
connecting bar 90 is connected to and spans the upper ends of the
shafts 86. As best seen in FIG. 6, a piston-cylinder device having
a piston 92 and a cylinder 94 is mounted on top of the mounting
block 72. Passage means 96 (FIG. 6) is formed within the mounting
block 72. The passage 96 is in communication with the interior of
the cylinder 94 at the bottom thereof and leads to an air hose or
conduit 98 which leads to an appropriate source of air pressure. A
piston rod 100 extends upwardly from the piston 92 through the
upper wall of the cylinder 94. A lever member 102 is pivotally
mounted on a shaft 104, as best seen in FIG. 6, and rests at one
end on top of the piston rod 100 and at its opposite end on top of
the connecting bar 90. Thus, as air pressure is admitted to the
cylinder 94 on the underside of the piston 92, the piston will move
upwardly in the direction of arrow H (FIG. 6) and, through the
piston rod 100, cause the lever member 102 to pivot about shaft 104
in the direction of arrow I to exert a downward force on the
connecting bar 90, and thus a downward force on the shafts 86 and
heat-sealing member 78. The heat-sealing member thereby is moved
downwardly into its extended sealing position. As the heat-sealing
member moves from about the knife toward its extended sealing
position, the sealing member strips the film from about the knife
and moves the film back to its original plane (i.e. prior to
applying suction to the film) where it is heat sealed to the lower
film F' over the partition 36. With this structural arrangement,
the two sheets of film are heat sealed in their original plane and
there is no resulting distortion of the formed package. Coil
springs 106 are disposed about the shafts 86 to urge the
heat-sealing member 78 back to its retracted position when the air
pressure is released from the cylinder 94 on the underside of the
piston 92.
After the two continuous sheets or layers of film from the upper
and lower supply rolls thereof have passed through the forming and
loading stations and have reached the sealing and evacuating
station, with pockets P formed in the lower sheet of film F' loaded
with the product, and with the upper sheet of film disposed in
juxtaposition above the lower sheet. The sealing and evacuating
process of the present invention is as follows. The lower section
32b of the heat-sealing device 32 is raised by means of the linkage
structure 52 and the cam 57 (FIGS. 4 and 5) into sealing position
beneath the upper section 32a, as best seen in FIGS. 6 and 7, with
the sheets of film sandwiched between the downwardly depending lips
60 and 62 of the upper section 32a and the insert members 38 and
40, respectively, of the lower section 32b. The sheets of film,
with the pocket P in the lower sheet thereof within the wells 34 of
the lower section 32b, thus are sealed about the periphery thereof
and partially along the partition 36 between the wells of the lower
section 32b. Suction then is applied to the lower sheet of film F'
through the vacuum hose 44 and passages 42 at the underside of the
lower section 32b of the heat-sealing device to grip the lower
sheet of film. Suction then is applied through the vacuum hose 76,
passage means 74 in the mounting block 72, and openings 70b in the
sleeve 70 to the upper sheet of film to cause the upper sheet to
move upwardly toward the knife blade 66 to form a pierced opening
in the upper sheet. The suction on the upper sheet is continued to
exhaust the air from between the two sealed sheets. Air pressure
then is admitted to the bottom of the cylinder 94 beneath the
piston 92 to cause the heat-sealing member 78 to move downwardly in
the direction of arrows G (FIGS. 6 and 7), stripping the film from
about the knife blade 66 and heat sealing the two sheets of film in
an area surrounding the pierced opening formed by the knife blade,
with the two sheets of film generally in their original planes
(i.e. prior to applying the suction thereto). The vacuum applied to
both the upper and lower sections 32a and 32b, respectively, of the
heat-sealing device 32 is released simultaneously so that the two
sheets of film will retract and cling snugly against the products
contained in the pockets formed between the two sheets of film. The
air pressure in the cylinder 94 then is released so that the
heat-sealing member 78 is biased back to its retracted position by
the springs 106. The lower section then is retracted and the sealed
and evacuated packages are separated by the cutter 26 and conveyed
from the machine.
FIGS. 8 through 11 show schematically the above sequence of steps
of evacuating the air from between the two sheets of film. FIG. 8
shows suction being applied to the lower section of the
heat-sealing device to grip the lower sheet of film; suction being
applied to the upper section of the heat-sealing device to draw the
upper sheet of film into piercing engagement with the knife blade,
and with the heat-sealing member surrounding the knife blade
disposed in its retracted position. FIG. 9 is similar to FIG. 8 and
shows the upper sheet of film having been pierced and the air from
between the sheets of film being evacuated through the pierced
opening. FIG. 10 shows the heat-sealing member which surrounds the
knife blade moved downwardly relative to the knife blade to strip
the upper sheet of film from the knife and heat seal the two sheets
of film in an area surrounding the pierced opening with the upper
sheet returned to the plane of the top of the packages. FIG. 11 is
a view similar to FIG. 10, with the vacuum released on the two
sheets of film so that the film retracts and clings to the product
packaged therebetween.
A control box 110 (FIGS. 1 and 3) is disposed behind the sealing
and evacuating station 22 and houses control means including an
appropriate conventional electrical cam, appropriate conventional,
solenoid-operated air and vacuum valves, and appropriate pneumatic
and electric circuitry to control the timing of the vacuum for the
lower section 32b of the heat-sealing device, the vacuum for the
upper section 32a, and the air pressure applied to the cylinder 94.
The cam is synchronized with the cam 57. It should be noted that
the packaging machine described above is adapted to form clusters
of two pockets P side by side in the lower continuous sheet of film
F, as best seen in FIG. 3. However, it should be understood that
the machine, and particularly the means and method of sealing and
evacuating the packages, is equally adaptable for a wide variety of
package shapes and clusters.
The foregoing detailed description has been given for clearness of
understanding only and no unnecessary limitations should be
understood therefrom as some modifications will be obvious to those
skilled in the art.
* * * * *