Information
-
Patent Grant
-
6817163
-
Patent Number
6,817,163
-
Date Filed
Friday, November 1, 200221 years ago
-
Date Issued
Tuesday, November 16, 200419 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
- Wood, Herron & Evans, LLP
-
CPC
-
US Classifications
Field of Search
US
- 053 550
- 053 568
- 053 3894
- 053 64
- 493 476
- 493 478
-
International Classifications
-
Abstract
An automatic high-speed wrapping system for wrapping packages in heat sealable thermoplastic film includes a film delivery unit wherein the film is dispensed and wrapped around the packages at a high rate of speed as the packages travel through the system. The packages travel continuously in a straight line through the system and are delivered at the input end of the system by a feed conveyor into a wrapping station where the packages are surrounded by the film, thence to the side sealing mechanism which forms a seal while severing the salvage from the packages, then into an end sealing mechanism where both ends of the packages are sealed and the film web connecting succeeding packages is severed. The film is delivered to the wrapping station in two plies and subsequently inverted for wrapping around the products. The positions of the wrapping station and film delivery units are adjustable to efficiently accommodate a variety of product heights while providing proper film delivery geometry.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to the art of film wrapping systems for use in wrapping objects with shrink wrap film, such as polyurethane wrapping film, and more particularly to improvements directed to dispensing such film from a film roll.
A wide variety of systems are known for wrapping packages in thermoplastic film. Some of these machines are known as L-sealers because they form “trim seals” utilizing a web of center folded film. More recent machines have utilized a continuous longitudinal sealer and a cross sealer which moves at approximately the velocity of the packages as they travel through the machine so that it is not necessary to stop the packages while performing the end sealing operation. Such prior art machines have generally been of three types. One type had a continuous side sealer and a complex series of multiple flighted end sealing jaws which were spaced for a particular product. This type required substantial set-up time for change in length of product to be wrapped. A second machine of this type, while making packages similar to those produced on an L-sealer worked by drawing film off a roll under tension, folding it around the product, drawing it past a hot knife side sealing mechanism and then formed the end seal with a moving end sealer.
A third type of machine had an overlapped longitudinal seal on the top or bottom of the wrapped packages. Since the overlap not only ran along the bottom of the packages but also ran halfway up both ends, the packages lacked the neat appearance and hence the sales appeal of the trim sealed packages as made on the L-sealers. Since many of the products so wrapped are sold in self-service retail stores, the appearance of the package has an important effect on the sales of the product. An additional disadvantage of the overlapped seal is that the width of the web of film must be precisely correct, requiring an exact width film for each size of product.
Shrink wrap packaging systems of these types process and wrap a variety of different products. Commonly, such products are of differing shapes, sizes and dimensions. For example, shrink wrap packaging systems may process and wrap a single compact disc (CD) package which is very thin or other consumer retail items which have a significantly greater height and larger vertical dimension.
One problem associated with most known shrink wrap packaging system is the difficulty to efficiently process and wrap a wide variety of packages and products, especially those having distinctly different dimensions and heights. For example, most known shrink wrap packaging systems utilize film which is provided on a roll in two plies with each ply being joined together by a longitudinal fold line. The two-ply film is dispensed from the supply roll typically in a direction generally perpendicular to the feed direction of the products to be wrapped. As the film is dispensed and delivered to a wrapping station of the shrink wrap packaging system, it is commonly inverted and reoriented to provide an opening for convenient access and entry of the products between the dual plies of the film. The film is reoriented by an upper and a lower film inverting rod or plow system. The upper and lower film inverting rods are positioned above and below, respectively, the feed conveyor which is advancing the products to be wrapped. Examples of such an arrangement are shown in U.S. Pat. Nos. 3,583,888; 3,583,889; 4,035,983; and 4,219,988, each of which are incorporated by reference herein.
The film inverter rods disclosed in the above-identified patents are each fixed relative to one another so that the spacing between the inverter rods is fixed. Recent advancements in the art of shrink wrap packaging systems have included adjustable film inverter rods to accommodate a variety of differing height products being wrapped. As such, the spacing between the film inverter rods may be adjustable.
However, one problem associated with adjustable film inverter rods is that the delivery of the two-ply film to the film inverter rods is often misaligned providing for poor geometry for the film being delivered to the film inverter rods once the spacing between the inverter rods is changed. Optimally the free edges of the upper and lower plies should be generally aligned with one another downstream from the film inverter rods for proper wrapping of the products and positioning of the side seam on the product. However, when the upper film inverter rod is moved relative to the lower film inverter rod for a different height product, the geometry of the film being delivered and processed at the wrapping station becomes misaligned. As a result, the film will not track properly and will not be in the required tubular configuration at the wrapping station. This requires readjustment and/or refeeding of the film through the various rollers, significant operator involvement and down time of the packaging system. The misalignment of the upper and lower plies of the film results in improperly wrapped products, side seals on the products which are located in a conspicuous or improper location, inefficient use or waste of the film wrapping material and other associated problems.
Therefore, a need exists in the shrink wrap packaging industry for a packaging system which can readily accommodate a wide variety of product configurations and heights without the above-described problems associated with known film delivery systems and wrapping operations.
SUMMARY OF THE INVENTION
These and other objectives have been achieved with this invention, which in one embodiment includes a film delivery unit for a shrink wrap packaging system. The film wrapping system includes a feed conveyor to delivery a series of products to a wrapping station. The wrapping station includes a pair of film inverter rods which are adjustable for spacing from one another to correspond to the height of the product being wrapped. A film delivery unit dispenses a supply of two-ply film in a direction generally perpendicular to the feed direction of the products. The two-ply film is inverted by the inverter rods at the wrapping station where the products are inserted between the plies of the film. The system includes a film inverter rod adjustment mechanism to adjust the spacing between the rods.
The system also includes a film delivery unit adjustment mechanism to adjust a position of the film delivery unit and the film being delivered to the wrapping station as a function of the spacing between the film inverter rods and, consequently, the height of the product being wrapped. In one embodiment of this invention, the film delivery unit adjustment mechanism moves the film delivery unit and the supply of film upstream in the feed direction relative to the film inverter rods for larger height products and downstream for smaller height products. Additionally, the system in another embodiment includes an adjustable roller positioned between the film delivery unit and the wrapping station to deliver the film to the wrapping station at a desired height relative to the position of the film inverter rods.
The shrink wrap packaging system also includes a side seal mechanism and an end seal mechanism each located downstream in the feed direction from the wrapping station to join the first and second plies together and enclose each of the products in individually wrapped packages. A heat shrink tunnel in one embodiment is located downstream from the sealing mechanisms to heat the film and thereby shrink it around the product as is well known in the industry.
As a result of the film delivery unit and associated adjustment mechanism according to this invention, a variety of product configurations and heights can be conveniently and efficiently wrapped while adjusting the spacing between the film inverter rods without fouling the geometry of the film delivery system and thereby avoiding the associated problems and disadvantages of shrink wrap packaging systems in the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
The objectives and features of the invention will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
FIG. 1
is a top view of a film wrapping system and associated method according to one embodiment of this invention;
FIG. 1A
is a view similar to
FIG. 1
of a portion of the wrapping system with a film delivery unit re-positioned;
FIG. 2
is a schematic view of a series of products as they travel through the system and in addition showing a film folding operation;
FIG. 3
is a perspective view of the film delivery unit and a product wrapping station of the system of
FIG. 1
;
FIG. 4
is schematic end view of the components of
FIG. 3
with a portion of the film delivery unit removed to show the film path; and
FIG. 5
is plan view of the film delivery unit of FIG.
3
.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to
FIG. 1
, a top view of an exemplary automatic high-speed film packaging system
10
according to one embodiment of this invention is shown. The system
10
generally includes a feed conveyor
12
, a film delivery unit
14
, a wrapping station
16
, a side sealer
18
, an end sealer
20
, associated downstream conveyor(s)
22
and a heat shrink tunnel
24
. Products P to be wrapped in film
26
enter the system
10
via a feed conveyor
12
. The conveyor
12
delivers the spaced-apart and generally aligned products P to the wrapping station
16
where a folded film
26
from a film roll
28
in the film delivery unit
14
surrounds each product P. The folded film
26
enveloping each product P is sealed at its free edges
30
,
30
by the side sealer
18
to form a tube of film
26
enclosing the spaced products P. The film salvage
32
(
FIG. 2
) at the sealed edge
34
is severed and removed. The film
26
between the adjacent products P is sealed and severed at the end sealer
20
to produce individual sealed packages of the product P.
The system
10
wraps a product P in a flexible plastic film
26
in which the travel of the product P is essentially continuous through the system
10
in a feed direction indicated by arrow A. The film
26
may be any one of a variety of films well known in the art and is supplied to the system
10
as a folded web at right angles to the feed direction of the product P (shown in
FIGS. 1 and 2
) through the system. The film
26
is provided to upper and lower inverter rods
36
a
,
36
b
of the wrapping station
16
where the film
26
is redirected and turned inside out to travel in the feed direction with the products P delivered by the feed conveyor
12
.
The feed conveyor
12
pushes products P into the wrapping station
16
to cause them to be enclosed by the folded film
26
supplied by film delivery unit
14
on the top, bottom, and one side of the product P with the other side of the product P adjacent to the free edges
30
,
30
of the folded film
26
being open initially. The product P thus enclosed in the web of film
26
travels with the film
26
past the side sealing mechanism
18
in
FIG. 1
which seals the two free edges
30
,
30
of the folded film
26
together to form a continuous tube of film which envelops the succession of products P which are being fed into the system
10
by feed conveyor
12
. The side sealer
18
also severs the excess width
32
of film
26
from the tube and this salvage
32
is removed by a salvage accumulator
38
, such as a vacuum or other take-up mechanism.
As the product P progresses further through the system
10
, the end sealing mechanism
20
seals the trailing edge
40
of each package while simultaneously sealing the leading edge
42
of the succeeding package in the system and it also severs one package from the other while the packages are traveling without stopping through the system
10
. The end seal mechanism
20
is so designed that it travels a short distance with the product P at substantially the same velocity while the seal is being made. After the seal has been made, the sealing mechanism
20
releases from the film
26
and returns to its original position to repeat the transverse seal for the next product. The wrapped product may then be conveyed through the shrink tunnel
24
for shrinking of the film around the product. While exemplary embodiments of the side sealer
18
, end sealer
20
and shrink tunnel
24
are shown and described herein as part of the system, specific models or embodiments of these components could readily be varied or changed as known by one of ordinary skill in this art without departing from the scope of this invention.
Because the product P being wrapped in the film proceeds through the system
10
at a substantially uniform velocity, the system
10
is capable of operating at film web speeds as high as 120 feet per minute although 60 to 100 feet per minute is a more typical speed. The system
10
is capable of wrapping in excess of one product P per second.
FIG. 2
shows the various stages of wrapping of successive products P
1
-P
5
with the plastic film
26
as the products proceed through the system
10
. Product P
5
is shown in
FIG. 2
as being partially covered by the folded film
26
as it passes between the inverter rods
36
a
,
36
b
. Product P
4
is shown exiting the side sealer
18
with the salvage
32
of the film
26
being separated from the side sealed package P
4
and being collected by salvage accumulator
38
. The side sealer
18
produces the side seal
34
that completes the tube envelope of relatively loose plastic film
26
around the products P.
The end sealing mechanism
20
produces a trim seal between the packages P
3
and P
2
. The end sealing mechanism
20
also severs the film
26
to provide product P
3
with a leading edge
42
and product P
4
with a trailing edge
40
. The product P
1
is shown as it exits from the heat shrink tunnel
24
where the loose fitting film envelope is shrunk to form a tight fitting film cover. The system
10
is designed to accommodate a variety of product heights and configurations as shown by product P
3
having a greater height than the other products. It will be appreciated that
FIG. 2
is schematic and the relative positions of the products P
1
-P
5
and associated components of the system
10
have been adjusted for simplification.
The component parts and the assembly in combination of the continuous high-speed wrapping system
10
of
FIG. 1
will now be discussed in detail, focusing in particular on the wrapping station
16
and the film delivery unit
14
.
Preferably, the product P is centered with respect to the feed conveyor
12
by means of guides (not shown) as is readily understood by those skilled in this art. The film
26
is folded about a longitudinal fold
44
thereby forming upper and lower plies
46
a
,
46
b
in which each ply has a free edge
30
opposite from the fold line
44
. Commonly, the two-ply folded film
26
is provided on the supply roll
28
. Alternatively, single ply film may be provided on a supply roll and subsequently folded into the described two-ply configuration as is well known in the art.
As shown particularly in
FIGS. 1
,
2
and
4
, the two-ply film
26
is delivered from the supply roll
28
by the film delivery unit
14
in a direction indicated by arrow B generally perpendicular to the feed direction (arrow A) of the products P. As the film
26
enters the wrapping station
16
, each ply
46
a
,
46
b
is guided around one of the film inverter rods
36
a
,
36
b
and thereby redirected approximately 90° to travel in the feed direction of arrow A. The film inverter rods
36
a
,
36
b
are oriented approximately 45° with respect to the feed direction. In addition to being redirected, the film
26
is inverted by the film inverter rods such that confronting inner first faces
48
,
48
of the film
26
provided by the film delivery unit
14
are inverted so that previously outer second faces
50
,
50
of the plies
46
a
,
46
b
of the film
26
are juxtaposed to each other and around the product P downstream from the film inverter rods
36
a
,
36
b.
As shown particularly in
FIGS. 3 and 4
, each film inverter rod
36
a
,
36
b
is joined to a pair of mounting rods
52
,
54
to form a generally triangular configuration. Mounting rod
52
is oriented generally parallel to the feed direction; whereas, mounting rod
54
is oriented generally perpendicular to the feed direction. An inclined guide tab
56
is mounted proximate the intersection of each film inverter rod
36
and the associated mounting rod
52
. The intersection between each film inverting rod
36
and the associated mounting rod
52
provides a reference point R which will be discussed herein below.
Film inverter rods
36
a
,
36
b
and the associated mounting rods
52
,
54
are mounted to a hub
58
a
,
58
b
, respectively. The hub
58
b
for the lower film inverter rod
36
b
is fixed beneath the feed conveyor
12
. The hub
58
a
for the upper film inverter rod
36
a
is mounted on a film inverter rod adjustment mechanism
60
to adjust a spacing S between the upper and lower film inverter rods
36
a
,
36
b
in a direction generally perpendicular to the feed direction (i.e., vertically) to accommodate products P of differing heights. The film inverter rod adjustment mechanism
60
in one embodiment includes an operator hand wheel
62
mounted atop a threaded rod
64
to rotate the rod
64
. The hub
58
a
includes a threaded aperture
66
engaged with the threaded rod
64
as well as two additional apertures
68
,
68
through which guide rods
70
,
70
project. In operation of the system
10
, the operator rotates the hand wheel
62
in the appropriate direction to raise or lower the upper film inverter rod
36
a
so that the upper ply
46
a
of the film
26
is positioned slightly above the top upper surface of the product P being wrapped. The upper and lower film inverter rods
36
a
,
36
b
, as well as the film inverter rod adjustment mechanism
60
, are mounted to a block
72
which is supported on a platform
74
underlying the lower film inverter rod
36
b
as well as the feed conveyor
12
. A frame
76
supports the wrapping station
16
, associated film inverter rod components as well as the film delivery unit
14
as shown in FIG.
3
. The downstream conveyors
22
and associated components are not shown in
FIG. 3
to provide a better view of the components in the wrapping station
16
and the film delivery unit
14
.
The film delivery unit
14
, as shown generally in
FIGS. 3-5
, is mounted adjacent to the wrapping station
16
in a direction generally perpendicular to the feed direction. The film delivery unit
14
supplies film
26
from the supply roll
28
to the wrapping station
16
. The supply roll
28
is supported by a cradle assembly
78
of the film delivery unit
14
. The cradle assembly
78
includes a pair of spaced cradle rollers
80
,
80
mounted for rotation between spaced end plates
82
,
82
of the cradle assembly
78
. The supply roll
28
is positioned atop the cradle rollers
80
,
80
and between a pair of film roll retainer posts
84
a
,
84
b
. Preferably, the gap between the film roller retainer posts
84
a
,
84
b
is adjustable to accommodate supply rolls
28
of different lengths. Specifically, in one embodiment, the downstream film roll retainer post
84
b
is joined to a bracket
86
that is secured by a set screw
88
in a slot
90
of front frame member
92
in the cradle assembly
78
. To adjust the spacing between the film roll retainer post
84
a
,
84
b
for different length supply rolls
28
, the operator would loosen the set screw
88
and slide the bracket
86
and associated film roll retainer post
84
b
along the slot
90
to the appropriate position to capture the supply roll
28
between the film roll retainer post
84
a
,
84
b.
Referring to
FIG. 4
, the path of the film
26
from the supply roll
28
through the delivery unit
14
and to the wrapping station
16
is shown. The supply roll
28
rotates on the cradle rollers
80
,
80
and the film
26
is fed around a lower deflecting roller
94
toward a film splitter insert
96
. The film splitter insert
96
advantageously separates or loosens the two film plies
46
a
,
46
b
from one another to avoid difficulty downstream in the film path in case the film
26
has an excessive buildup of static electricity, is particularly tacky or otherwise resistant to having the plies
46
a
,
46
b
separated. After the film splitter insert
96
, the film
26
travels between a pair of nip rollers
98
,
100
and downwardly around a dancer roller
102
. The lower nip roller
98
is preferably rubber and is coupled to a belt drive
104
trained around the output shaft of a motor
106
. The motor
106
rotates the rubber nip roller
98
thereby pulling the film
26
from the supply roll
28
. The motor
106
which drives the roller
98
must turn the supply roll
28
in a direction to provide film
26
to the wrapping station
16
. The motor
106
must at all times provide film
26
in excess of the maximum speed of the feed conveyor
12
to ensure minimum tension of the film
26
as it passes over the film inverter rods
36
a
,
36
b
. The dancer roller
102
is coupled to a tension arm
108
for pivotal movement about a tension pivot
110
to maintain tension on the film
26
. If slack in the film
26
develops because of an interruption in the flow of products P, for example, the tension arm
108
is coupled to a controller (not shown) for the motor
106
to interrupt the dispensing of the film
26
until additional film is required by the wrapping station
16
. As such, film tension is controlled by the dancer roller
102
through the tension arm
108
in association with the control of the motor
106
.
The upper nip roller
100
may include a number of pins or spikes
112
to perforate the film
26
passing between the nip rollers
98
,
100
as is customary in the shrink wrap industry. The film
26
passes around an intermediate deflecting roller
114
and an upper deflecting roller
116
before exiting the film delivery unit
14
. The various rollers
94
,
98
,
100
,
102
,
114
and
116
extend between a pair of spaced sidewalls
156
,
156
of the film delivery unit
14
.
The system
10
includes a film delivery height adjustment roller
118
positioned between the film delivery unit
14
and the wrapping station
16
. The roller
118
is mounted between a pair of arms
120
,
120
which are coupled to corresponding links
122
mounted to the frame
76
. Advantageously, the position of the arms
120
,
120
and subsequently the position of the roller
118
is adjustable to deliver the film
26
to the wrapping station
16
at an appropriate height relative to the position of the film inverter rods
36
a
,
36
b
. Preferably, the vertical position of the roller
118
is equal distance between the upper and lower film inverter rods
36
a
,
36
b
. Since the spacing S between the film inverter rods is adjustable, the height of the film delivery roller
118
is likewise adjustable to provide for proper positioning relative to the film inverter rods
36
a
,
36
b
. The arm
120
supporting the roller
118
includes a set screw
124
which is captured within an arcuate slot
126
in a guide plate
128
. Adjustment of the roller
118
height is accomplished by the operator by loosening the set screw
124
and pivoting the arms
120
coupled to the roller
118
upwardly or downwardly as desired and then resecuring the set screw
124
with the roller
118
in the appropriate position approximately midway between the upper and lower film inverter rods
36
a
,
36
b
. As the film
26
passes around the roller
118
, the two plies
46
a
,
46
b
are separated and guided by the respective film inverter rods
36
a
,
36
b
to surround the product P on the conveyor
12
.
As shown particularly in
FIGS. 3-5
, the film delivery unit
14
is movably mounted relative to the frame
76
on a pair of spaced generally tubular rails
130
,
130
. In one embodiment, each of the rails
130
extends generally in the feed direction and is supported on one of a pair of spaced generally U-shaped brackets
132
mounted to a lower portion of the frame
76
. The film delivery unit
12
moves on the rails
130
,
130
by a series of support roller bearings
134
. Each support roller bearing
134
is mounted for rotation between a pair of downwardly depending support plates
136
,
136
mounted on a lower surface of the film delivery unit
14
. Preferably, each pair of support plates
136
,
136
has two upper and one lower support roller bearing
134
mounted therebetween for rotation along the respective rail
130
. The support roller bearings
134
are positioned as generally shown in
FIG. 5
to provide support and stable movement along the rails
130
,
130
of the film delivery unit
14
as required.
The position of the film delivery unit
14
is adjustable on the rails
130
,
130
in a direction generally parallel to the feed direction in via a film delivery unit adjustment mechanism
138
. The film delivery unit adjustment mechanism
138
according to one embodiment of this invention provides for proper positioning and delivery of the film
26
to the wrapping station
16
as a function of the spacing S between the film inverter rods
36
a
,
36
b
. Specifically, in one embodiment, the film delivery unit adjustment mechanism
138
includes an adjustment knob
140
mounted for rotation and projecting from casing
142
mounted to the frame
76
. The adjustment knob
140
is mounted for rotation relative to the casing
142
and is coupled to a threaded rod
144
which is engaged in a threaded aperture
146
in one of the sidewalls
156
of the film delivery unit
14
. As such, rotation of the adjustment knob
140
and the threaded rod
144
attached thereto moves the film delivery unit
14
in a lateral direction, as shown in
FIG. 5
, or upstream/downstream relative to the feed direction. Proper positioning of the film delivery unit
14
and the supply roll
28
according to this invention provides for accurate and precise film
26
geometry as it is delivered through the film delivery unit
14
to the wrapping station
16
. Preferably, the film inverter rods
36
a
,
36
b
in the wrapping station
16
remain stationary as the position of the film delivery unit
14
is adjusted.
In particular, it has been determined that the relative position of the film inverter rods
36
a
,
36
b
in the feed direction compared to the leading or upstream edge
148
of the film supply roll
28
mounted on the delivery unit
14
is important to maintain proper geometry of the film
26
being dispensed from the supply roll
28
through the delivery unit
14
and applied at the wrapping station
16
to the products P on the conveyor
12
. The relative position of the upstream edge
148
of the supply roll
28
in comparison to the reference point R on the film inverter rods
36
a
,
36
b
is utilized to provide for proper film delivery geometry.
As the spacing S between the upper and lower film inverter rods
36
a
,
36
b
is adjusted to accommodate different height products P, movement of the film delivery unit
14
in a direction generally parallel to the feed direction is required to maintain proper film delivery geometry. For products P which are extremely thin and having little or no height such as a CD lying generally flat on the feed conveyor
12
, the reference point R on the film inverter rods
36
a
,
36
b
is generally aligned with the upstream edge
148
of the supply roll
28
on the film delivery unit
14
. However, the film delivery unit
14
must be moved in a direction generally parallel to the feed direction as the spacing S between the film inverter rods
36
a
,
36
b
is adjusted to accommodate different height products P.
In operation, the spacing S between the film inverter rods
36
a
,
36
b
is adjusted to accommodate the product P height. Once the film inverter rods
36
a
,
36
b
are so adjusted, the position of the film delivery height adjustment roller
118
is likewise set by the operator to be approximately equal distance between the film inverter rods
36
a
,
36
b
. The film delivery unit
14
is then moved relative to the reference point R on the film inverter rods
36
a
,
36
b
to provide for proper alignment, geometry and delivery of the film
26
to the wrapping station
16
. According to one embodiment of this invention, the film delivery unit
14
is moved via the adjustment knob
140
along the rails
130
one-half inch to adjust for each inch in package height to establish the correct film delivery geometry. The film inverter rods
36
a
,
36
b
at the wrapping station
16
should remain stationary as the film delivery unit
14
position is adjusted. For each inch increase in product height, the position of the film delivery unit
14
is adjusted one-half inch in the upstream direction. Conversely, for each inch decrease in package height or spacing between the film inverter rods
36
a
,
36
b
, a half-inch movement of the film delivery unit
14
in the downstream feed direction is required for correct film geometry.
For example, as shown in
FIG. 1
, the relative position of the edge
148
of the supply rod
28
compared to the reference point R provides appropriate tracking and film
26
delivery geometry for a product such as P
3
of FIG.
2
. However, for a product P
4
of lesser height, the spacing S is decreased and the edge
148
is adjusted with the film delivery unit
14
downstream parallel to the feed direction to a position relative to reference point R as shown in FIG.
1
A.
A product height indicator
150
is provided to indicate the spacing S between the film inverter rods
36
a
,
36
b
. A product height adjustment scale
152
is mounted on the frame
76
and an indicator
154
moves with the film delivery unit
14
so that the operator may accurately position the film delivery unit
14
relative to the inverter rods
36
a
,
36
b
. While the adjustment mechanisms
60
and
138
, as well as the positioning of roller
118
, are shown and described herein as being independent from each other, alternative embodiments of this invention include automatic adjustment of the positions of the film roll
28
and/or roller
118
in response to changes to the spacing S.
An important feature of this invention is the positioning of the film delivery unit
14
and the supply roll
28
thereon relative to the film inverter rods
36
a
,
36
b
in the feed direction. According to one embodiment of this invention, the film delivery unit adjustment mechanism
138
adjusts the position of the film delivery unit
14
in the upstream or downstream directions. Alternatively, the position of the film inverter rods
36
a
,
36
b
relative to the feed direction may be adjusted by movement of the block
72
relative to the frame
76
and supply roll
28
to provide for the appropriate relative position between the film inverter rods
36
a
,
36
b
and the supply roll
28
mounted on the film delivery unit
14
. Nevertheless, as a result of this invention, proper film delivery geometry from the supply roll to the film inverter rods can be easily and efficiently obtained in conjunction with the adjusted spacing between the film inverter rods to accommodate varying height products without fouling the delivery of the film along the film path and maintaining alignment of the free edges of the plies of the film wrapped around the products.
From the above disclosure of the general principles of the present invention and the preceding detailed description of at least one preferred embodiment, those skilled in the art will readily comprehend the various modifications to which this invention is susceptible. Therefore, I desire to be limited only by the scope of the following claims and equivalents thereof.
Claims
- 1. A film wrapping system for wrapping products of differing heights in film, the system comprising:a feed conveyor adapted to delivery a series of products in a feed direction; a film delivery unit adapted to dispense a supply of film having first and second plies joined together along a longitudinal fold line, each of the first and second plies having a free edge spaced from and generally parallel to the longitudinal fold line and a first face opposite from a second face, the respective first faces of the plies being juxtaposed to one another at the film delivery unit; a film feed direction of the film exiting the film delivery unit being generally perpendicular to the feed direction of the products; a wrapping station adapted to receive the film from the film delivery unit and to wrap each of the products delivered thereto by the feed conveyor; a first and a second film inverter rod at the wrapping station, the film inverter rods being spaced from one another and each film inverter rod being adapted to guide one of the plies of film toward each of the products delivered to the wrapping station; wherein the film inverter rods cooperate to invert the first and second plies so that the respective second faces of the plies are juxtaposed to one another and to the product being wrapped at the wrapping station; a film inverter rod adjustment mechanism operable to adjust a spacing between the film inverter rods in a direction generally perpendicular to the feed direction to accommodate products of differing heights; and a film delivery unit adjustment mechanism operable to adjust a position of the film delivery unit relative to the film inverter rods in a direction generally parallel to the feed direction; the film delivery unit adjustment mechanism adjusting the position of the film delivery unit as a function of the spacing between the film inverter rods.
- 2. The system of claim 1 wherein the position of the film inverter rods is fixed in the feed direction and the film delivery unit adjustment mechanism moves the film delivery unit alternately upstream and downstream parallel to the feed direction and relative to the position of the film inverter rods.
- 3. The system of claim 1 wherein the film inverter rods are oriented about 45° relative to the feed direction and the film delivery unit delivers the film to the wrapping station in a direction generally perpendicular to the feed direction.
- 4. The system of claim 1 wherein a ratio of the spacing between the film inverter rods to the position of the film delivery unit relative to a reference point on the film inverter rods is about 2:1.
- 5. The system of claim 1 wherein the film delivery unit adjustment mechanism moves the film delivery unit upstream in the feed direction relative to the film inverter rods for larger height products and downstream for smaller height products.
- 6. The system of claim 1 further comprising:a side seal mechanism located downstream in the feed direction from the wrapping station to join the first and second plies together proximate the respective free edges of the plies.
- 7. The system of claim 1 further comprising:an end seal mechanism located downstream in the feed direction from the wrapping station to join the first and second plies together in a direction generally perpendicular to the feed direction.
- 8. The system of claim 1 further comprising:a heat shrink tunnel located downstream in the feed direction from the wrapping station to heat the film and thereby shrink it around the product.
- 9. The system of claim 1 further comprising:an adjustable roller positioned intermediate the film delivery unit and the wrapping station, wherein a position of the roller is adjustable in a direction generally perpendicular to the feed direction and relative to the film inverter rods to thereby deliver the film to the wrapping station at a desired height.
- 10. The system of claim 1 further comprising:a product height indicator to indicate a height of the product being wrapped at the wrapping station and provide a reference for the appropriate position of the film delivery unit.
- 11. A film wrapping system for wrapping products of differing heights in film, the system comprising:a feed conveyor adapted to delivery a series of products in a feed direction; a film delivery unit adapted to dispense a supply of film having first and second plies joined together along a longitudinal fold line, each of the first and second plies having a free edge spaced from and generally parallel to the longitudinal fold line and a first face opposite from a second face, the respective first faces of the plies being juxtaposed to one another at the film delivery unit; a wrapping station adapted to receive the film from the film delivery unit and to wrap each of the products delivered thereto by the feed conveyor; the film delivery unit delivering the film to the wrapping station in a direction generally perpendicular to the feed direction; a first and a second film inverter rod at the wrapping station, the film inverter rods being fixed relative to the feed direction and spaced from one another and each film inverter rod being adapted to guide one of the plies of film toward each of the products delivered to the wrapping station; wherein the film inverter rods cooperate to invert the first and second plies so that the respective second faces of the plies are juxtaposed to one another and to the product being wrapped at the wrapping station, the film inverter rods being oriented about 45° relative to the feed direction; an adjustable roller positioned intermediate the film delivery unit and the wrapping station, wherein a position of the roller is adjustable in a direction generally perpendicular to the feed direction and relative to the film inverter rods to thereby deliver the film to the wrapping station at a desired height; a film inverter rod adjustment mechanism operable to adjust a spacing between the film inverter rods in a direction generally perpendicular to the feed direction to accommodate products of differing heights; and a film delivery unit adjustment mechanism operable to adjust a position of the film delivery unit relative to the film inverter rods in a direction generally parallel to the feed direction, the film delivery unit adjustment mechanism moves the film delivery unit upstream in the feed direction relative to the film inverter rods for larger height products and downstream for smaller height products; the film delivery unit adjustment mechanism adjusting the position of the film delivery unit as a function of the spacing between the film inverter rods; a side seal mechanism located downstream in the feed direction from the wrapping station to join the first and second plies together proximate the respective free edges of the plies; an end seal mechanism located downstream in the feed direction from the side seal mechanism to join the first and second plies together in a direction generally perpendicular to the feed direction; and a heat shrink tunnel located downstream in the feed direction from the wrapping station to heat the film and thereby shrink it around the product.
- 12. The system of claim 11 wherein a ratio of the spacing between the film inverter rods to the position of the film delivery unit relative to a reference point on the film inverter rods is about 2:1.
- 13. A film wrapping system for wrapping products of differing heights in film, the system comprising:a feed conveyor adapted to delivery a series of products in a feed direction; a film delivery unit adapted to dispense a supply of film having first and second plies joined together along a longitudinal fold line, each of the first and second plies having a free edge spaced from and generally parallel to the longitudinal fold line and a first face opposite from a second face, the respective first faces of the plies being juxtaposed to one another at the film delivery unit; a film feed direction of the film exiting the film delivery unit being generally perpendicular to the feed direction of the products; a wrapping station adapted to receive the film from the film delivery unit and to wrap each of the products delivered thereto by the feed conveyor; a first and a second film inverter rod at the wrapping station, the film inverter rods being spaced from one another and each film inverter rod being adapted to guide one of the plies of film toward each of the products delivered to the wrapping station; wherein the film inverter rods cooperate to invert the first and second plies so that the respective second faces of the plies are juxtaposed to one another and to the product being wrapped at the wrapping station; a film inverter rod adjustment mechanism operable to adjust a spacing between the film inverter rods in a direction generally perpendicular to the feed direction to accommodate products of differing heights; and an adjustable roller positioned intermediate the film delivery unit and the wrapping station, wherein a position of the roller is adjustable in a direction generally perpendicular to the teed direction and relative to the film inverter rods to thereby deliver the film to the wrapping station at a desired height.
- 14. The system of claim 13 wherein the film inverter rods are oriented about 45° relative to the feed direction and the film delivery unit delivers the film to the wrapping station in a direction generally perpendicular to the feed direction.
- 15. The system of claim 13 further comprising:a film delivery unit adjustment mechanism operable to adjust a position of the film delivery unit relative to the film inverter rods in a direction generally parallel to the feed direction; the film delivery unit adjustment mechanism adjusting the position of the film delivery unit as a function of the spacing between the film inverter rods.
- 16. The system of claim 15 wherein the position of the film inverter rods is fixed in the feed direction and the film delivery unit adjustment mechanism moves the film delivery unit alternately upstream and downstream parallel to the feed direction and relative to the position of the film inverter rods.
- 17. The system of claim 15 wherein a ratio of the spacing between the film inverter rods to the position of the film delivery unit relative to a reference point on the film inverter rods is about 2:1.
- 18. The system of claim 15 wherein the film delivery unit adjustment mechanism moves the film delivery unit upstream in the feed direction relative to the film inverter rods for larger height products and downstream for smaller height products.
US Referenced Citations (22)
Foreign Referenced Citations (1)
Number |
Date |
Country |
153408 |
Jun 1986 |
JP |