U.S. patent application number 11/232672 was filed with the patent office on 2006-05-25 for film side sealing apparatus with closed-loop temperature control of a heater.
This patent application is currently assigned to Shrink Packaging Systems Corp.. Invention is credited to John J. Gilbert, Frank A. James, Jeffrey C. Lindberg.
Application Number | 20060107622 11/232672 |
Document ID | / |
Family ID | 35520531 |
Filed Date | 2006-05-25 |
United States Patent
Application |
20060107622 |
Kind Code |
A1 |
James; Frank A. ; et
al. |
May 25, 2006 |
Film side sealing apparatus with closed-loop temperature control of
a heater
Abstract
A side sealing apparatus for a shrink packaging machine
comprising closed loop temperature control of a heater for
maintaining an optimum temperature for cutting and sealing two
layers of thermoplastic film. The heater comprises a cable or
cartridge heater with an internal thermocouple, and it is connected
to an automatic temperature controller. The heater is mounted on
the side sealer apparatus between two sets of top and bottom
V-belts mounted around drive rolls and idler rolls. The V-belts
provide nip pressure against the film in order to drive the film.
In one embodiment, nip pressure is generated by nip rollers on the
scrap side of the film, and by low friction belt support guides on
the package side of the film. In another embodiment, the belt
support guides are replaced with a series of upper and lower nip
rollers, and adjustable toggle clamps provide adjustable pressure
on the series of upper and lower nip rollers.
Inventors: |
James; Frank A.; (Nashua,
NH) ; Lindberg; Jeffrey C.; (Merrimack, NH) ;
Gilbert; John J.; (Lowell, MA) |
Correspondence
Address: |
PEARSON & PEARSON, LLP
10 GEORGIA STREET
LOWELL
MA
01852
US
|
Assignee: |
Shrink Packaging Systems
Corp.
|
Family ID: |
35520531 |
Appl. No.: |
11/232672 |
Filed: |
September 22, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10994691 |
Nov 22, 2004 |
|
|
|
11232672 |
Sep 22, 2005 |
|
|
|
Current U.S.
Class: |
53/479 ;
53/374.5 |
Current CPC
Class: |
B29C 66/961 20130101;
B65H 2404/25 20130101; B29C 65/305 20130101; B65B 51/18 20130101;
B29C 66/91421 20130101; B29C 66/91651 20130101; B65H 2404/261
20130101; B29C 65/7873 20130101; B29C 66/91431 20130101; B29C
65/749 20130101; B29C 66/836 20130101; B65G 15/14 20130101; B29C
65/7439 20130101; B29C 66/73921 20130101; B29C 65/18 20130101; B29C
66/133 20130101; B29C 66/4312 20130101; B29C 66/91641 20130101;
B29C 66/9241 20130101; B29C 66/91231 20130101; B29C 66/8242
20130101; B29C 66/949 20130101; B29C 66/4322 20130101; B65B
2051/105 20130101; B29C 66/87441 20130101; B29C 66/8324 20130101;
B65B 9/06 20130101; B29C 66/91212 20130101; B65H 2404/264 20130101;
B29C 66/849 20130101; B29C 66/8221 20130101; B65H 37/04
20130101 |
Class at
Publication: |
053/479 ;
053/374.5 |
International
Class: |
B65B 7/02 20060101
B65B007/02 |
Claims
1. A side sealer apparatus for cutting and sealing two layers of
film together near an edge of heat-sealable material comprising:
means for moving the heat-sealable material through the side sealer
apparatus; means attached to said side sealer apparatus in the path
of said heat-sealable material for generating heat to cut and seal
said heat-sealable material near said edge; a top drive roll
spaced-apart from a top idler roll; a bottom drive roll
spaced-apart from a bottom idler roll and positioned immediately
under the top drive roll and top idler roll respectively; a first
pair of spaced-apart V-belts positioned around and between the top
drive roll and the top idler roll on a side of the apparatus above
the moving means; a second pair of spaced-apart V-belts positioned
around and between the bottom driver roll and the bottom idler
roll; a top belt guide, having a low coefficient of friction and a
bottom groove for a lower portion of an outer one of the first pair
of spaced apart V-belts to travel in, to provide nip pressure on
the heat-sealable material; and a bottom belt guide, having a low
coefficient of friction and a top groove for an upper portion of an
outer one of the second pair of spaced apart V-belts to travel in,
to provide nip pressure on the heat-sealable material.
2. The side sealer apparatus as recited in claim 1 wherein: said
heat generating means is mounted on said side sealer apparatus at a
predetermined angle relative to horizontal between the V-belts
positioned on an inner side of the heater and the V-belts
positioned on an outer side of the heater.
3. The side sealer apparatus as recited in claim 1 wherein said
heat-sealable material comprises a thermoplastic film.
4. The side sealer apparatus as recited in claim 1 wherein said
heat generating means comprises an elongated metal sheathed body
including an internal heating mechanism and a thermocouple.
5. The side sealer apparatus as recited in claim 1 wherein said
moving means comprises a conveyor.
6. The side sealer apparatus as recited in claim 1, wherein said
apparatus comprises means connected to said heat generating means
for providing closed loop control of said heat generating means in
accordance with a predetermined heat setting.
7. A side sealer apparatus for cutting and sealing two layers of
heat-sealable film together near an edge comprising: means for
moving the heat-sealable material through said side sealer
apparatus; means attached to said side sealer apparatus in the path
of said heat-sealable film for generating heat to cut and seal said
heat-sealable film together near said edges; a top drive roll
spaced-apart from a top idler roll; a bottom drive roll
spaced-apart from a bottom idler roll and positioned immediately
under said top drive roll and said top idler roll respectively; a
first pair of spaced-apart V-belts positioned around and between
said top drive roll and said top idler roll on a side of the
apparatus above the moving means; a second pair of spaced-apart
V-belts positioned around and between said bottom driver roll and
said bottom idler roll; a plurality of pairs of upper nip rollers
positioned between said top drive roll and said top idler roll and
in contact with a lower portion of said first pair of spaced-apart
V-belts; a plurality of pairs of lower nip rollers positioned
between said bottom drive roll and said bottom idler roll and in
contact with an upper portion of said second pair of spaced-apart
V-belts; and means for providing an adjustable nip pressure on said
pairs of upper nip rollers in contact with said first pair of
spaced-apart V-belts.
8. The side sealer apparatus as recited in claim 7 wherein said
moving means comprises a conveyor.
9. The side sealer apparatus as recited in claim 7 wherein said
heat generating means comprises an elongated metal sheathed body
including an internal heating mechanism and a thermocouple.
10. The side sealer apparatus as recited in claim 7 wherein said
heat-sealable film comprises a thermoplastic film.
11. The side sealer apparatus as recited in claim 7 wherein: said
heat generating means is mounted on said side sealer apparatus at a
predetermined angle relative to horizontal between one of said
V-belts positioned on an inner side of the heater and one of said
V-belts positioned on an outer side of the heater.
12. The side sealer apparatus as recited in claim 7, wherein said
apparatus comprises means connected to said heat generating means
for providing closed loop control of said heat generating means in
accordance with a predetermined heat setting.
13. The side sealer apparatus as recited in claim 7 wherein said
means for providing an adjustable nip pressure on said pairs of
upper nip rollers in contact with said first pair of spaced-apart
V-belts comprises: a nip roller mounting frame for holding said
upper nip rollers in a horizontal row, said nip roller mounting
frame being attached to a wall of said side sealer via a hinge; and
means for applying pressure to an upper surface of said nip roller
mounting frame to produce said adjustable nip pressure.
14. The side sealer as recited in claim 13, wherein said pressure
applying means comprises at least one toggle clamp having a leg
extending to and in contact with said upper surface of said nip
roller mounting frame.
15. A side sealer apparatus for cutting and sealing of
heat-sealable film together near an edge comprising: means attached
to said side sealer apparatus in a path of said heat-sealable film
for generating heat to cut and seal said heat-sealable film
together near an edge; a top drive roll spaced-apart from a top
idler roll; a bottom drive roll spaced-apart from a bottom idler
roll and positioned immediately under said top drive roll and said
top idler roll respectively; a first pair of spaced-apart V-belts
positioned around and between said top drive roll and said top
idler roll on a side of the apparatus above the moving means; a
second pair of spaced-apart V-belts positioned around and between
said bottom driver roll and said bottom idler roll; a plurality of
pairs of upper nip rollers positioned between said top drive roll
and said top idler roll and in contact with a lower portion of said
first pair of spaced-apart V-belts; a plurality of pairs of lower
nip rollers positioned between said bottom drive roll and said
bottom idler roll and in contact with an upper portion of said
second pair of spaced-apart V-belts; and means for providing an
adjustable nip pressure on said pairs of upper nip rollers in
contact with said first pair of spaced-apart V-belts.
16. The side sealer apparatus as recited in claim 15, wherein said
heat generating means comprises an elongated metal sheathed body
including an internal heating mechanism and a thermocouple.
17. The side sealer apparatus as recited in claim 15, wherein said
heat-sealable film comprises a thermoplastic film.
18. The side sealer apparatus as recited in claim 15 wherein: said
heat generating means is mounted on said side sealer apparatus at a
predetermined angle relative to horizontal between one of said
V-belts positioned on an inner side of the heater and one of said
V-belts positioned on an outer side of the heater.
19. The side sealer apparatus as recited in claim 15, wherein said
apparatus comprises means connected to said heat generating means
for providing closed loop control of said heat generating means in
accordance with a predetermined heat setting.
20. The side sealer apparatus as recited in claim 15, wherein said
means for providing an adjustable nip pressure on said pairs of
upper nip rollers in contact with said first pair of spaced-apart
V-belts comprises: a nip roller mounting frame for holding said
upper nip rollers in a horizontal row, said nip roller mounting
frame being attached to a wall of said side sealer via a hinge; and
means for applying pressure to an upper surface of said nip roller
mounting frame.
21. The side sealer as recited in claim 20, wherein said pressure
applying means comprises at least one toggle clamp having a leg
extending to and in contact with said upper surface of said nip
roller mounting frame.
22. A method for cutting and sealing two layers of heat-sealable
film together near an edge in a side sealer apparatus comprising
the steps of: moving said heat-sealable film through said side
sealer apparatus; generating heat to cut and seal said
heat-sealable film together near said edge with means attached to
said side sealer apparatus in the path of said film; providing a
top drive roll spaced-apart from a top idler roll on said side
sealer apparatus; providing a bottom drive roll spaced-apart from a
bottom idler roll on said side sealer and positioned immediately
under said top drive roll and said top idler roll respectively;
positioning a first pair of spaced-apart V-belts around and between
said top drive roll and said top idler roll on a side of said side
sealer apparatus above said means for moving said film; positioning
a second pair of spaced-apart V-belts around and between said
bottom driver roll and said bottom idler roll; attaching a
plurality of pairs of upper nip rollers between said top drive roll
and said top idler roll and in contact with a lower portion of said
first pair of spaced-apart V-belts; attaching a plurality of pairs
of lower nip rollers between said bottom drive roll and said bottom
idler roll and in contact with an upper portion of said second pair
of spaced-apart V-belts; and providing an adjustable nip pressure
on said pairs of upper nip rollers in contact with said first pair
of spaced-apart V-belts.
23. The method as recited in claim 22 wherein said step of moving
said heat-sealable film through said side sealer apparatus
comprises the step of providing a conveyor.
24. The method as recited in claim 22 wherein said step of
generating heat comprises the step of providing an elongated metal
sheathed body including an internal heating mechanism and a
thermocouple.
25. The method as recited in claim 22 wherein said method comprises
the step of sealing thermoplastic film.
26. The method as recited in claim 22 wherein said step of
generating heat comprises the step of mounting a heat generating
means on said side sealer apparatus at a predetermined angle
relative to horizontal between one of said V-belts positioned on an
inner side of the heater and one of said V-belts positioned on an
outer side of the heater.
27. The method as recited in claim 22 wherein said step of
generating heat to cut and seal said heat-sealable film comprises
the step of providing closed loop control of means for generating
said heat in accordance with a predetermined heat setting heat
setting.
28. The method as recited in claim 22 wherein said step of
providing an adjustable nip pressure on said pairs of upper nip
rollers in contact with said first pair of spaced-apart V-belts
comprises the steps of: holding said upper nip rollers in a
horizontal row with a nip roller mounting frame, said nip roller
mounting frame being attached to a wall of said side sealer via a
hinge; and applying pressure to an upper surface of said nip roller
mounting frame to move said mounting frame downward and provide
said adjustable nip pressure.
29. The method as recited in claim 28, wherein said step of
applying pressure comprises the step of providing at least one
toggle clamp having a leg extending to and in contact with said
upper surface of said nip roller mounting frame.
Description
[0001] This application is a Continuation-In-Part of prior
application Ser. No. 10/994,691, filed Nov. 22, 2004, now pending
which is herein incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to a side sealer of
thermoplastic film around a dimensioned article, and in particular
to a side sealing apparatus having an internally heated sealing bar
integrated with a closed-loop temperature controller operating
essentially in free air supported by thin clips in order to
minimize heat transfer to the overall assembly, allowing the heater
to cut and seal a thermoplastic film in as tight a temperature
range as possible, while allowing the overall temperature of the
entire unit to operate at close to room temperature.
[0004] 2. Description of Related Art
[0005] A commonly used side sealer of thermoplastic film in shrink
wrapping machines comprises dual hot wires. The hot wires are
typically two (2) eight inch heated nichrome wires mounted
parallel, one on top of the other. The wires are separated by a gap
of approximately 0.010 inches to 0.015 inches (the thickness of an
average business card). Adjusting and maintaining this gap is
critical for proper sealing and cutting of the film web as this
film is cut and sealed by radiant heat from the opposing wires. The
wires utilized in this arrangement must be installed completely
flat against the backing material, in this case, 1 inch long
ceramic "beads" or blocks. No bowing or slight kinks in the wires
can be tolerated as a uniform gap must be maintained. Access to
these wires requires removal of cover plates and film drive belts.
Frequent cleaning of resin buildup is necessary. Cleaning the wires
without disturbing the gap setting or flatness of the wire is very
difficult. Readjustment of the gap is usually necessary. All of
this results in lost production time.
[0006] Further, the performance of the dual side sealer is often
not stable over extended periods of operation even when initially
adjusted to optimum settings. A significant cause of this
instability is the drift in wire temperatures over time due to
drifts in power conditions typical in many factories. The wire
temperature is subject to open loop control, i.e. any changes in
factory power feed conditions or operating conditions will cause
the wire temperature to change, and conversely, will require an
operator to manually adjust the electrical power values to the wire
power feed in order to bring the wire temperature back to the
desired sealing temperature. Another inherent problem with the dual
wire side sealer is the fact that many side sealer components heat
up to undesirably high temperatures during operation of the side
sealer as a result of the sealing wires radiating heat and its
mounting being in contact with the frame they are mounted on which
conducts heat to the main assembly resulting in resin build-up
during production runs. The heat build-up is detrimental to
successful side sealing requiring frequent stopping of the machine
in order to clean the molten film build-up on the individual wire
assemblies. The resin build-up is a result of unintentional heating
of the area of the film that is close to, but outside of, the
actual seal area. This unintentionally heated film becomes soft and
is prone to stick to components that it contacts, particularly if
the side sealer frame components are already at an elevated
temperature. In addition, the dual wire side sealer has a large
parts count, and coupled with the fact that it operates at an
overall elevated temperature, the side sealer belts and bearings
are subject to frequent failure, resulting in attendant high
maintenance costs. In addition, when the dual wire sealer is
inoperable for any reason, it requires sufficient time to cool down
in order to restore its operation due to the excessive operating
temperature of the entire unit, which frequently reaches
temperatures of 135 degrees F. A typical cleaning and resetting
will take at least 1 hour, resulting in lost production for that
period of time.
[0007] Prior art patents include U.S. Pat. No. 6,526,728 issued
Mar. 4, 2003 to Gregg R. Sorenson et al. and assigned to Conflex
Incorporated of Milwaukee, Wis. discloses a thermoplastic film side
sealing mechanism comprising a hot wire assembly having a hot wire
mounted between a stationary mounting block and a pivoting mounting
block. The hot wire also diverges at an angle which is about 0.32
inches over an 8.125 inch run. The divergence is at an angle
relative to the path of forwardly disposed belts. The pivoting
mounting block provides for releasing tension of the wire to allow
quick and easy removal of the wire ends from the assembly clamps.
However, there is no closed loop control of the temperature of the
hot wire and resin build-up occurs requiring frequent
maintenance.
SUMMARY OF THE INVENTION
[0008] Accordingly, it is therefore an object of this invention to
provide a closed loop temperature controller for precise
temperature control of a heater that directly contacts the film to
cut and seal on a side sealer.
[0009] It is a further object of this invention to provide low
coefficient of friction belt support plates or guides on the
package side of the sealer to generate nip pressure between top and
bottom V-belts which exert nip pressure against the film to drive
the film.
[0010] It is another object of this invention to provide a side
sealer apparatus having an upper series of nip rollers and a lower
series of nip rollers in contact with the V-belts for generating a
nip pressure to drive the film wherein the nip pressure provided by
the upper series of nip rollers is adjustable by means of a toggle
clamp.
[0011] It is another object of this invention to provide a heat
source that closely approximates an ideal sealing temperature of a
particular thermoplastic film with a given thickness, and the heat
source that cuts the film will operate at precisely the ideal
temperature so as to produce consistent film strength seals with no
residue and pleasing aesthetics with a wide range of thermoplastic
materials, which is not possible with present technology.
[0012] It is another object of this invention to provide a
simplified side sealer of thermoplastic film by attaching a
temperature controlled heater having an internal or external
thermocouple in the path of the film for sealing the film on a side
of a product that requires no adjustment other than setting the
required temperature for sealing a particular film type and gauge
at a specific speed.
[0013] It is a further object of this invention to provide a method
for sealing a thermoplastic film covering a product by using an
elongated heater attached to a closed loop temperature controller
and mounting the heater at an angle in the path of the film near
the edges to be sealed.
[0014] These and other objects are accomplished by a side sealer
apparatus for cutting and sealing two layers of film together near
an edge of heat-sealable material comprising, means for moving the
heat sealable material through the side sealer apparatus, means,
attached to the side sealer in the path of heat-sealable material,
for generating heat to cut and seal the heat-sealable material near
the edge, means connected to the heat generating means for
providing closed loop control of the heat generating means in
accordance with a predetermined heat setting, a top drive roll
spaced-apart from a top idler roll on a side of said apparatus
above said moving means, a bottom drive roll spaced-apart from a
bottom idler roll and positioned immediately under the top drive
roll and top idler roll respectively, a first pair of spaced-apart
V-belts positioned around and between the top drive roll and the
top idler roll on a side of the apparatus above the moving means, a
second pair of spaced-apart V-belts positioned around and between
the bottom driver roll and the bottom idler roll, a top belt guide,
having a low coefficient of friction and a bottom groove for a
lower portion of an outer one of the first pair of spaced apart
V-belts to travel in, to provide nip pressure on the heat sealable
material, and a bottom belt guide, having a low coefficient of
friction and a top groove for an upper portion of an outer one of
the second pair of spaced apart V-belts to travel in, to provide
nip pressure on the heat sealable material. The heat generating
means is mounted on the side sealer apparatus at a predetermined
angle relative to horizontal between the V-belts positioned on an
inner side of the heater and the V-belts positioned on an outer
side of the heater. The heat-sealable material comprises a
thermoplastic film. The heat generating means comprises an
elongated metal sheathed body including an internal heating
mechanism and a thermocouple. The moving means comprises a
conveyor.
[0015] The objects are further accomplished by a side sealer
apparatus for cutting and sealing of heat-sealable film together
near an edge comprising a means attached to the side sealer
apparatus in the path of the heat-sealable film for generating heat
to cut and seal the heat-sealable film together near the edge, a
top drive roll spaced-apart from a top idler roll, a bottom drive
roll spaced-apart from a bottom idler roll and positioned
immediately under the top drive roll and the top idler roll
respectively, a first pair of spaced-apart V-belts positioned
around and between the top drive roll and the top idler roll on a
side of the apparatus above the moving means, a second pair of
spaced-apart V-belts positioned around and between the bottom
driver roll and the bottom idler roll, a plurality of pairs of
upper nip rollers positioned between the top drive roll and the top
idler roll and in contact with a lower portion of the first pair of
spaced-apart V-belts, a plurality of pairs of lower nip rollers
positioned between the bottom drive roll and the bottom idler roll
and in contact with an upper portion of the second pair of
spaced-apart V-belts, and means for providing an adjustable nip
pressure on the pairs of upper nip rollers in contact with the
first pair of spaced-apart V-belts. The side sealer apparatus
comprises a conveyor for moving the heat-sealable film through the
apparatus. The heat generating means comprises an elongated metal
sheathed body including an internal heating mechanism and a
thermocouple. The heat-sealable film comprises a thermoplastic
film. The heat generating means is mounted on the side sealer
apparatus at a predetermined angle relative to horizontal between
one of the V-belts positioned on an inner side of the heater and
one of the V-belts positioned on an outer side of the heater. The
apparatus comprises means connected to the heat generating means
for providing closed loop control of the heat generating means in
accordance with a predetermined heat setting. The means for
providing an adjustable nip pressure on the pairs of upper nip
rollers in contact with the first pair of spaced-apart V-belts
comprises a nip roller mounting frame for holding the upper nip
rollers in a horizontal row, the nip roller mounting frame being
attached to a wall of the side sealer via a hinge, and means for
applying pressure to an upper surface of the nip roller mounting
frame. The pressure applying means comprises at least one toggle
clamp having a leg extending to and in contact with the upper
surface of the nip roller mounting frame.
[0016] These objects are further accomplished by providing a method
for cutting and sealing two layers of heat-sealable film together
near an edge in a side sealer apparatus comprising the steps of
moving the heat-sealable film through the side sealer apparatus,
generating heat to cut and seal the heat-sealable film together
near the edge with means attached to the side sealer apparatus in
the path of the film, providing a top drive roll spaced-apart from
a top idler roll on the side sealer apparatus, providing a bottom
drive roll spaced-apart from a bottom idler roll on the side sealer
and positioned immediately under the top drive roll and the top
idler roll respectively, positioning a first pair of spaced-apart
V-belts around and between the top drive roll and the top idler
roll on a side of the side sealer apparatus above the means for
moving the film, positioning a second pair of spaced-apart V-belts
around and between the bottom driver roll and the bottom idler
roll, attaching a plurality of pairs of upper nip rollers between
the top drive roll and the top idler roll and in contact with a
lower portion of the first pair of spaced-apart V-belts, attaching
a plurality of pairs of lower nip rollers between the bottom drive
roll and the bottom idler roll and in contact with an upper portion
of the second pair of spaced-apart V-belts, and providing an
adjustable nip pressure on the pairs of upper nip rollers in
contact with the first pair of spaced-apart V-belts.
[0017] Additional objects, features and advantages of the invention
will become apparent to those skilled in the art upon consideration
of the following detailed description of the preferred embodiments
exemplifying the best mode of carrying out the invention as
presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The appended claims particularly point out and distinctly
claim the subject matter of this invention. The various objects,
advantages and novel features of this invention will be more fully
apparent from a reading of the following detailed description in
conjunction with the accompanying drawings in which like reference
numerals refer to like parts, and in which:
[0019] FIG. 1 is a front elevational view of a side sealer
according to the present invention;
[0020] FIG. 2 is a top view of the side sealer of FIG. 1 showing
scrap film separating after the film passes through a heater;
[0021] FIG. 3 is a diagram of a side sealer having a heater
connected to a closed loop controller for setting and maintaining
the temperature of the heater;
[0022] FIG. 4 is a front elevational view of the side sealer of
FIG. 1 having top and bottom belt support plates attached;
[0023] FIG. 5 is a fragmentary cross-section taken along lines 5-5
of FIG. 4 showing top and bottom belt support plates positioned for
contact with V-belts on a package side;
[0024] FIG. 6 is a top view of a side sealer system showing the
method of film wrapping;
[0025] FIG. 7A is an end view of a folded film as it comes off a
film roll;
[0026] FIG. 7B is an end view of the folded film with open edges
before side sealing and after it has been inverted;
[0027] FIG. 7C is an end view of the film being held open by an
inverting head to enable a package to enter within the film
envelope;
[0028] FIG. 7D is an end view of the folded film of FIG. 6C after
side sealing a product within the film;
[0029] FIG. 8 is a front elevational view of a top belt guide;
[0030] FIG. 9 is a side elevational view of the top belt guide of
FIG. 8;
[0031] FIG. 10 is a bottom view of the top belt guide of FIG.
8;
[0032] FIG. 11 is a front elevational view of a bottom belt
guide;
[0033] FIG. 12 is a side elevational view of the bottom belt guide
of FIG. 11;
[0034] FIG. 13 is a top view of the bottom belt guide of FIG.
11;
[0035] FIG. 14 is a front elevational view of an alternate
embodiment of a side sealer according to the present invention;
[0036] FIG. 15 is a top view of the side sealer of FIG. 14 with
V-belts removed;
[0037] FIG. 16 is a partial front perspective view of FIG. 14
showing an adjustable toggle clamp in an opened position;
[0038] FIG. 17 is an exploded left side elevational view of the
side sealer showing top and bottom drive roll or pulleys, upper and
lower nip rollers attached to a nip roller mount, and toggle clamp
mounted above the nip roller mount;
[0039] FIG. 18 is a cross-sectional view of the side sealer of FIG.
14 taken along lines 18-18; and
[0040] FIG. 19 is a rear perspective view of film tracking rollers
on an end of the side sealer.
DESCRIPTION OF ILLUSTRATIVE EMBODIMENT
[0041] Referring to FIG. 1 and FIG. 2, FIG. 1 is a front
elevational view of a side sealer 10 according to the invention
with belt support plates removed, and FIG. 2 is a top view of the
side sealer 10 shown in FIG. 1. The side sealer 10 performs a
cutting and sealing operation near edges of a thermoplastic film 42
covering a package 50 using a heater 28. The side sealer 10
comprises a top drive roll 12 and a bottom drive roll 18, a top
idler roll 14 and a bottom idler roll 20. There are two sets of
V-belts that drive a film 42 to be sealed along a conveyor 52 (FIG.
6) through the side sealer 10. A top set includes two upper V-belts
15, 16 which are positioned around and between top driver roll 12
and the idler roll 14. A bottom set includes two lower V-belts 21,
22 which are positioned around and between the bottom drive roll 18
and the bottom idler roll 20. The heater 28 is mounted to the side
sealer between the inner package side top and bottom belts 16 and
22 and the scrap side top and bottom belts 15 and 21, and the
heater 28 is positioned on an angle of approximately two degrees
more or less relative to horizontal so that it intersects the path
of the film 42 depending on the film type to be sealed. The top and
bottom belts 16 and 22 are on the package side and oriented between
the drive roll 12 and the idler roll 14 parallel to the conveyor
52, while the top and bottom belts 15 and 21 on the scrap side of
the film 42 are angled away from the conveyor 52. The heater 28 is
controlled by heater controller 38.
[0042] The side sealer 10 comprises an upper series of nip rolls
24a-24e and a lower series of nip rolls 26a-26e mounted directly
under the upper series of nip rolls 24a-24e. The V-belts need to
exert a "nip" pressure against the film 42 in order to drive the
film 42. The nip rolls 24a-24e and 26a-26e are used to generate the
nip pressure on the top and bottom scrap side V-belts 15 and 21.
However, belt support plates or guides 25, 27 (FIG. 4) are used to
generate nip pressure between the top and bottom V-belts 16, 22 on
the package side. For example, a top belt support plate or guide 25
is manually pushed downward to create the nip force before the top
belt support plate or guide 25 is screwed into place.
[0043] Referring now to FIG. 3, a diagram of the heater controller
38 connected to the heater 28 by a cable 30 is illustrated for
setting and maintaining the temperature of the heater 28. The
heater controller 38 comprises a closed loop temperature controller
which maintains a predetermined set temperature to within less than
one percent. The closed-loop controller may be embodied by
temperature controller Model 93 manufactured by Watlow of St.
Louis, Mo. 63146. The heater 28 comprises a metal sheathed body
with resistive internal electrical wiring as a preferred
embodiment. The heater 28 is attached to the side sealer 10 by
heater brackets 44, 45 which are mounted on a heater frame 46.
[0044] When an electrical current is applied to the heater 28 via
wires 34a, 34b, the internal mechanism generates heat that is
efficiently transferred to the metal sheath of the heater 28. By
varying the electrical power to the heater 28, the temperature of
the heater 28 can be increased or decreased. The heater replaces
pairs of nichrome resistive wires used in prior art open loop dual
wire systems. It also replaces other methods of cutting and sealing
of films on side sealer equipment. In operation the two layers of
the film 42 that are to be cut and sealed together are guided into
intimate and precise contact with the heater 28. Heat is
efficiently transferred from the heater 28 to the film 42 producing
a strong, consistent seal.
[0045] Still referring to FIG. 3, a thermocouple, commonly known in
the art, is embedded within the sheath of the heater 28, as a
preferred embodiment. Alternatively, a thermocouple external to the
heater can be positioned in close proximity to the heater. The
thermocouple generates an electrical signal that is proportional to
the temperature of the heater 28. The thermocouple signal is
carried via wires 36a, 36b to heater controller 38 for closed loop
control of the temperature of heater 28. The operation of the
closed loop control system embodied by the heater controller 38 and
the heater 28 is as follows: an operator inputs a predetermined
temperature to the heater controller 38. The predetermined value is
based on previous experience and in general, depends on film type,
thickness, and the conveyor 52 (FIG. 6) speed. The heater
controller 38 receives a signal from the thermocouple in the heater
28 on a continuous basis. The heater controller 38 has
circuitry/logic that compares the actual temperature of the heater
28 (based on thermocouple signal) to the predetermined set
temperature. If the actual temperature of the heater 28 is
different than the set temperature, the controller adjusts the
electric power level to the heater 28 to cause the actual
temperature of the heater 28 to converge towards the set
temperature. This process of the heater controller 38 comparing
actual heater temperatures to set temperature occurs on a
continuous, real time basis. Thus, once the operator inputs the set
temperature to the heater controller 38, the heater temperature
will be maintained at the set temperature within a close range or
tolerance of less than one percent without any further operator
intervention, regardless of any fluctuating incoming voltage. The
heater controller 38 makes any adjustments required in response to
any changes in operational conditions on an automatic basis. The
heater 28 may be embodied by Cable Heater Part # 125FH014AX-1992
manufactured by Watlow Corporation of St. Louis, Mo. 63146. The
heater controller 38 may be embodied by Temperature Controller
Model #93AA-1CD0-00RG manufactured by Watlow Corporation of St.
Louis, Mo. 63146.
[0046] Referring to FIG. 4 and FIG. 5, FIG. 4 is a front
elevational view of the side sealer 10 of FIG. 1 according to the
present invention showing the top belt support plate or guide 25
and the bottom belt support plate or guide 27 attached to the side
sealer 10 which provide the nip pressure on the top and bottom
V-belts 16 and 22. FIG. 5 is a fragmentary cross-section taken
along lines 5-5 of FIG. 4 showing the top belt support plate or
guide 25 in contact with the lower portion of top V-belt 16 and the
bottom belt support plate or guide 27 in contact with the upper
portion of bottom V-belt 22 to provide the nip pressure on the
package side film drive belts 16, 22.
[0047] Referring to FIG. 6 and FIGS. 7A-7D, FIG. 6 is a top view of
a side sealer 60 showing the method of performing the side sealing
operation with the thermoplastic film 42 covering the product
50a-50d. FIGS. 7A-7D show the approximate appearance of the
thermoplastic film 42 at various stages in the process. The side
sealer system 60 comprises a conveyor 52 which moves the product
50a-50d onto the film 42 from right to left as indicated by arrow
61, and moves the product 50a-50d along the side sealer 10 for
cutting and sealing of the film 42. The film 42 comes off a roll 54
and is opened by a film inverting head 56 having an upper arm 62
and a lower arm 64, or in other cases, a film inverting head in
which the upper arm 62 and lower arm 64 (FIG. 7C) are manufactured
as a single piece.
[0048] Still referring to FIG. 6 and FIGS. 7A-7D, FIG. 7A shows the
thermoplastic film 42 as it comes off the roll 54 with an opening
43 on the left side and a folded side 45 on the right side. FIG. 7B
shows the film 42 reversed with the opening 43 on the right side,
which is the side that faces the side sealer 10, and the fold 45 on
the left side, which is the side facing the package 50. This
reversal of the film 42 is accomplished by the film inverting head
56 by draping the film 42 over the film inverting head 56, and arms
62, 64 open the film 42 so that a product 50C coming along the
conveyor 52 is enclosed by the film 42 prior to cutting and sealing
the upper and lower film edges 42a, 42b as illustrated in FIG. 7C.
FIG. 7D shows the film 42 after the film edges 42a and 42b are cut
and sealed by the side sealer 10.
First Alternate Embodiment
[0049] Referring to FIG. 8, a front elevational view of the top
belt guide 25 is shown having two elongated holes 72a, 72b to
facilitate attaching the belt guide 25 to the sides of the side
sealer 10 and adjusting the belt guide 25 against the lower portion
of V-belt 16, which is positioned between top drive roll 12 and
idler roll 14. The ends 71, 77 of the belt guide 25 are curved
inwardly at a radius to correspond with the radius of the pulley
rolls. In the preferred embodiment shown in FIGS. 8-10, the belt
guide 25 is approximately 11 inches long, 2.56 inches high and 0.25
inch thick; however, other sizes of belt guide 25 may be
implemented on a side sealer.
[0050] Referring to FIG. 9, a side elevational view of the top belt
guide 25 shows a bottom groove 70 having a radius of approximately
0.06 inch so that the belt only protrudes slightly into the groove
70 to minimize any undesired frictional force.
[0051] Referring to FIG. 10, a bottom view of the top belt guide 25
shows the groove 70 and the break point 73 where each of the bottom
ends of belt guide 25 slope upward at an angle 78 of approximately
ten degrees.
[0052] Referring to FIG. 11, a front elevational view of the bottom
belt guide 27 is shown, having three holes 79a, 79b, 79c for
attaching the belt guide 27 to the lower portion of the side sealer
10. The bottom belt guide 27 comprises a groove 74 along the length
of its top edge for receiving the upper portion of V-belt 22, which
is positioned between the bottom drive roll 18 and the bottom idler
roll 20. The ends 80, 81 of the belt guide 27 are curved inwardly
to correspond with the radius of the pulley rolls. In the preferred
embodiment shown in FIGS. 11-13, the bottom belt guide 27 is
approximately 11.25 inches long, 2.44 inches high, and 0.25 inches
thick; however, other sizes of bottom belt guide 25 may be
implemented on a side sealer.
[0053] Referring to FIG. 12, a side elevational view of the bottom
belt guide 27 shows the top groove 74 having a radius of
approximately 0.06 inch so that the belt 22 only protrudes slightly
into the groove 74 to minimize any undesired frictional force.
[0054] Referring to FIG. 13, a top view of the bottom belt guide 27
shows the groove 74 and the start of the break point 75 where the
top ends of belt guide 27 slope downward at an angle 82 of
approximately ten degrees.
[0055] In order to minimize frictional forces, the top belt guide
25 and the bottom belt guide 27 are made from a Delrin.RTM. plastic
such as Delrin.RTM. 15OE Homopolymer having a maximum continuous
use temperature of 185 degrees Fahrenheit and a dynamic coefficient
of friction of 0.20. It is manufactured by UNITAL. Other
manufacturers of low friction, high temperature plastic materials
may be substituted to embody the belt guide 25, 27.
Second Alternate Embodiment
[0056] Referring to FIG. 14, a front elevational view of a second
alternate embodiment of a side sealer 100 according to the present
invention is shown. Elements of side sealer 100 which are the same
as elements of the embodiment shown in FIG. 1 have the same
reference number. The side sealer 100 performs a cutting and
sealing operation the same as side sealer 10, but because of
certain improvements to be described, the side sealer 100 performs
a more efficient cutting and sealing operation near edges of a
thermoplastic film 42 for covering a package 50 (FIG. 2) by
eliminating lateral film 42 slippage while the film 42 is driven
through the sealing process by the V-belts 15, 16, 21, 22. In some
cases, the amount of thermoplastic film used is reduced with the
side sealer 100 embodiment because of increased grip on the film
42. The cutting and sealing is performed using the heater 28. The
second alternate embodiment shown in FIG. 14 employs a series of
upper rotating rollers 124a-124e and a series of lower rotating
rollers 126a-126e instead of the top belt guide 25 and bottom belt
guide 27 of FIG. 4.
[0057] Referring to FIG. 14 and FIG. 15, FIG. 15 is a top view of
the side sealer of FIG. 14 with the V-belts removed. The side
sealer 100 comprises a top drive roll 12 and a bottom drive roll
18, a top idler roll 14 spaced apart from the top drive roll 12 and
a bottom idler roll 20 spaced apart from the bottom drive roll 18,
an upper set of V-belts 15, 16 and a bottom set of V-belts 21, 22.
Similar to the embodiment shown in FIG. 1, the top set of V-belts
15, 16 are positioned around and between top drive roll 12 and the
idler roll 14 and the bottom set of V-belts 21, 22 are positioned
around and between the bottom drive roll 18 and the bottom idler
roll 20. The heater 28 extends from the cable 30 and is mounted to
the side sealer 100 between the inner package side top and bottom
belts 16 and 22 and the scrap side top and bottom belts 15 and 21.
The heater 28 is positioned at an angle of approximately two (2)
degrees relative to horizontal more or less depending on the film
to be sealed so that it intersects the path of the film 42 passing
through the side sealer 100. The top and bottom belts 16 and 22 are
on the package side and oriented between the drive roll 12 and the
idler roll 18 parallel to the conveyor 52 (FIG. 6), while the top
and bottom belts 15 and 21 on the scrap side of the film 42 are
angled away from the conveyor 52. The heater 28 is controlled by
heater controller 38 (FIG. 3).
[0058] Referring to FIG. 14-16, FIG. 16 is a partial front
perspective view of FIG. 14. The side sealer 100 comprises an upper
series of pairs of nip rollers 24a-24e and 124a-124e, extending
from a top nip roller mount 114 and a lower series of pairs of nip
rollers 26a-26e and 126a-126e, mounted directly under the upper
series of pairs of nip rollers 24a-24e and 124a-124e, extending
from a bottom nip roller mount 115. The V-belts 15, 16, 21, 22 ride
in the grooves of the nip rollers 24a-24e, 124a-124e, 26a-26e, and
126a-126e and provide a nip pressure against the film 42 in order
to drive the film 42. The side sealer embodiment shown in FIGS.
14-16 comprises a series of 5 pairs of nip rollers but additional
pairs of nip rollers may be used in larger embodiments of side
sealers. The nip pressure is adjusted by raising and lowering the
top nip roller mount 114 which is attached to a hinge 116.
Adjustable toggle clamp 102 attached to a toggle clamp mount 103
and toggle clamp 104 attached to toggle clamp mount 105 are used to
apply downward vertical pressure to set the appropriate nip
pressure on the film 42. A leg 106 of toggle clamp 102 comprises a
foot 107 which rests on top of the top nip roller mount 114, and
likewise a leg 108 of toggle clamp 104 comprises a foot 109 which
rests on top of the top nip roller mount 114. When the toggle
clamps 102 and 104 are closed, the feet 107, 109 push down on the
top of the nip roll mount 114 causing the series of the pair of
upper nip rollers 24a-24e and 124a-124e to apply nip pressure to
the upper set of V-belts 15, 16. Each of the legs 106 and 108 is
threaded, and therefore, the length of each leg is adjustable. Lock
nuts 113 and 115 on each of the toggle clamp legs are tightened to
maintain the correct nip pressure. When the toggle clamps 102, 104
increase the pressure on the series of the pairs of upper nip
rollers 24a-24e and 124a-124e additional pressure occurs between
the top and bottom drive belts 15, 16, 21, 22 that drive the film
42. The toggle clamps may be embodied by Model TC-601, manufactured
by Destaco Company of Birmingham, Mich. Instead of using toggle
clamps 102, 103, an air cylinder may be employed for applying a
force to the top nip roller mount 114.
[0059] There is substantially no drag between the V-belts 15, 16,
21, 22 and the series of upper and lower nip rollers in FIG. 14,
and therefore, there is no substantial amount of heat generated.
The level of downward vertical pressure that can be applied to the
series of upper nip rollers 24a-24e, 124a, 124e can be adjusted to
a pressure level not attainable with stationary belt guides. This
level of downward vertical pressure would stall the drive to the
side sealer 100 if the stationary belt guides 25, 27 were used.
This higher level of downward vertical pressure ensures that
adequate film drive will be maintained over long periods of
production runs, even when running high slip films or films that
are coated with slip agents that tend to transfer to and build up
on the drive V-belts, inhibiting the ability of the V-belts over
time to reliably drive the film.
[0060] Referring now to FIG. 17, FIG. 17 is an exploded left side
elevational view of the side sealer 100 showing the top and bottom
drive rolls or pulleys 12, 18 extending from bearing blocks 150,
152 and attached to drive shafts 146, 148 respectively. The toggle
clamp 102 is shown in the closed position and the foot 107 of leg
106 is pressing against the top of the top nip roller mount 114
which rotates around hinge 116. The pairs of upper nip rollers 24a
and 124a press down on V-belts 15, 16 which provide the adjustable
nip pressure on the film 42. Also shown in FIG. 17 are spur gear
144 and sprockets 154 and 156 for driving the top and bottom drive
rolls 12, 18.
[0061] Referring to FIG. 18, a cross-sectional view of the side
sealer 100 of FIG. 14 is shown taken along lines 18-18. Upper nip
rollers 24e-124e are shown with V-belts 15 and 16 positioned within
their grooves, and the lower portions of V-belts 15 and 16 are in
contact with the film 42. The pair of lower nip rollers 26e-126e
are mounted directly under the pair of upper nip rollers 24e, 124e,
and they assist in moving the film 42. Shafts 134 and 136 drive the
top drive shaft roll 12 and the bottom drive roll 18
respectively.
[0062] Referring to FIG. 19, a rear perspective view is shown of a
film guide assembly 160 comprising film tracking rollers 142, 143
attached to an end of the side sealer 100. The tracking rollers
142, 143 guide the film 42 into the side sealer 100, and they can
pivot for providing a lead-in angle. A safety jam micro-switch 162
is provided for shutting down the entire side sealer 100 if
something substantially thicker than the film 42 gets between the
rollers 142, 143. The micro-switch 162 mounts on a first end of top
arm 163 which is held in place by a bracket 172 having one end
attached to a rear wall 101 of side sealer 100 and the other end
bolted to an upper surface of a top arm 163. The second end of top
arm 163 comprises a mounting screw extending through the top arm
163 down to a support bar 167. The tracking roller 142 mounts on
the end of top guide 168, and tracking roller 143 mounts on the end
of bottom guide 170. A spring is connected between the top guide
168 and the bottom guide 170 for setting the correct tracking
tension on the film 42 as it passes through the tracking rollers
142, 143.
[0063] This invention has been disclosed in terms of certain
embodiments. It will be apparent that many modifications can be
made to the disclosed apparatus without departing from the
invention. Therefore, it is the intent of the appended claims to
cover all such variations and modifications as come within the true
spirit and scope of this invention.
* * * * *