U.S. patent application number 10/371660 was filed with the patent office on 2004-01-29 for method for stopping and starting an automatic machine for collectively wrapping products, especially rolls of toilet or kitchen paper.
This patent application is currently assigned to T.M.C. S.p.A.. Invention is credited to Castaldini, Giampaolo, Loperfido, Gianfranco.
Application Number | 20040016213 10/371660 |
Document ID | / |
Family ID | 11440338 |
Filed Date | 2004-01-29 |
United States Patent
Application |
20040016213 |
Kind Code |
A1 |
Loperfido, Gianfranco ; et
al. |
January 29, 2004 |
METHOD FOR STOPPING AND STARTING AN AUTOMATIC MACHINE FOR
COLLECTIVELY WRAPPING PRODUCTS, ESPECIALLY ROLLS OF TOILET OR
KITCHEN PAPER
Abstract
A method for stopping and restarting an automatic machine (1)
for wrapping products (2), in particular rolls of toilet or kitchen
paper, in a collective pack (3) using a packaging film (4a) unwound
from a first reel (31a), comprises the following automatic sequence
of steps: reducing the speed of the machine (1); and stopping the
feeding of the products (2) and of the film (4a) at suitably
synchronized intervals from each other relative to the processing
of the products (2); the method subsequently comprising the steps
of: substituting the first reel (31a) of the film (4a) with a
second reel (31b); loading the film (4b) on the second reel into
feed means (33, 34); restarting the machine (1) at reduced speed
and thereby automatically activating the following sequence of
steps: unwinding and positionally centering the film (4b); and
restarting the feeding of the products (2) and of the film (4a) at
suitably synchronized intervals from each other relative to the
products (2).
Inventors: |
Loperfido, Gianfranco;
(Lugo, IT) ; Castaldini, Giampaolo; (Baricella,
IT) |
Correspondence
Address: |
Richard J. Minnich, Esq.
Fay, Sharpe, Fagan, Minnich & McKee, LLP
Seventh Floor
1100 Superior Avenue
Cleveland
OH
44114-2518
US
|
Assignee: |
T.M.C. S.p.A.
|
Family ID: |
11440338 |
Appl. No.: |
10/371660 |
Filed: |
February 21, 2003 |
Current U.S.
Class: |
53/461 ;
53/396 |
Current CPC
Class: |
B65B 59/001 20190501;
B65H 19/1852 20130101; B65H 2301/46013 20130101; B65B 25/146
20130101; B65B 11/22 20130101; B65H 2701/1944 20130101; B65B 59/003
20190501; B65H 2513/20 20130101 |
Class at
Publication: |
53/461 ;
53/396 |
International
Class: |
B65B 011/18; B65B
041/12 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2002 |
IT |
BO2002A000493 |
Claims
What is claimed is:
1. A method for stopping and restarting an automatic machine (1)
for wrapping products (2), in particular rolls of toilet or kitchen
paper, in a collective pack using a packaging film (4a; 4b) unwound
from a reel (31a; 31b), the method comprising the following
automatic sequence of steps, triggered by the activation of a
control for stopping the machine (1): reducing the speed of the
machine (1) to a speed (V2) suitably lower than the working speed
(V1); stopping the infeed of the products (2) to the machine (1);
stopping the infeed of a first wrapping film (4a) to the machine
(1) with a delay of at least four steps after stopping the infeed
of the products (2); stopping the machine (1) after the products
(2) inside the machine (1) have moved at least three steps forward;
the method further comprising the steps of substituting the first
reel (31a) of wrapping film (4a) with a second reel (31b) of a
second film (4b); loading the film (4b) of the second reel (31b)
into the related film feed means (33, 34); restarting the machine
(1) and thereby automatically activating the following sequence of
steps: restarting wrapping film (4b) unwinding from the second reel
(31b); positionally centering the wrapping film (4b); restarting
the machine (1) at a reduced speed (V2), lower than the working
speed (V1); restarting product (2) infeed; restarting the infeed of
the sheets (18) of wrapping film to the machine with a delay of at
least four steps after restarting product (2) infeed.
2. The method according to claim 1, wherein the steps of
substituting the first reel (31a) with a second reel (31b) and
loading the film (4b) from the latter into the film feed means (33,
34) are performed manually.
3. The method according to claim 1, wherein the steps of
substituting the second reel (31b) and loading the film (4b) from
the latter into the film feed means (33, 34) are performed by an
automatic apparatus (6) which is activated by a signal relating to
the state of the film (4a) on the first reel (31a).
4. The method according to claim 1 or 2, wherein the steps of
substituting the second reel (31b) and loading the film (4b) into
the film feed means (33; 34) are performed when at least the size
of the wrapping film sheets (18) is varied.
5. The method according to claim 4, wherein the steps of
substituting the first reel (31a) with a second reel (31b) and
loading the film (4b) from the latter into the film feed means (33;
34) comprise a splicing step in which the film (4a) from the first
reel (31a) and the second film (4b) from the second reel (31b) are
joined along a splicing line (65) and proceed together lengthways
in a direction (78) in which the films (4a; 4b) are fed.
6. The method according to claim 4, comprising a step of checking
the current position of the splicing line (65) relative to a
predetermined reference system, where the splicing line (65), upon
reaching a predetermined position in the feed direction (78),
causes a signal to be issued in order to activate suitable
actuating means used to automatically adjust the distance between
means (33, 34, 55, 56) for guiding the film (4a; 4b) towards the
machine (1).
7. The method according to claim 6, wherein the signal stops the
feeding of the film (4a; 4b) in the feed direction (78) to restart
at a later stage when the distance between the guide means (33, 34;
55, 56) has been suitably adjusted.
8. The method according to claim 7, wherein the actuating means
comprise at least one drive motor (63; 75) for feeding the film
(4a, 4b) and equipped with means enabling engagement and
disengagement of film (4a; 4b) feed.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the automatic packaging of
products, in particular rolls of toilet or kitchen paper, wrapped
in collective packs using a film of packaging material.
[0002] The invention relates in particular to a method for stopping
and restarting an automatic machine for packaging these products,
advantageously used to optimize production changeover time and to
minimize the number of manual operations to be performed for this
purpose by personnel attending to the machine.
[0003] According to current packaging industry practices in the
field of the above mentioned products, changing over to a different
type of product, for example, when a programmed quantity of
products has been reached, means stopping an automatic packaging
machine and subjecting it to a whole range of operations in order
to adapt its parts and settings to the different product. The
completion of the setup and changeover procedure, however, involves
numerous operations which must be performed manually and in a set
order that must rigidly observed.
[0004] Basically, these operations are the following: stopping the
machine; removing the products remaining from the previous
production runs; setting the machine up for the new size packages
to be made; filling the machine with products for the new size
packages; and restarting the machine gradually before returning it
to normal production speed.
[0005] More specifically, these operations include:
[0006] manually stopping the means that feed the product to the
machine;
[0007] manually activating the function that removes the rolls of
the previous production run from the feed means and from the inside
of the machine itself;
[0008] manually removing from the machine the sheets of wrapping
film remaining from the previous production run;
[0009] manually substituting the film reel from which the product
wrapping sheets for the previous production run were drawn;
[0010] manually loading the end of the film on the substitute reel
into the related film feed means;
[0011] performing a few machine cycles at reduced speed in manual,
jogging mode in order to stabilize the wrapping film last
loaded;
[0012] re-starting the product feed system using the control panel
and screen;
[0013] performing a few machine cycles in manual mode in order to
fill the roll feed system;
[0014] manually removing the wrapping film sheets made during the
test cycles;
[0015] performing a few machine test cycles in manual mode; and
lastly,
[0016] manually switching to automatic mode and waiting for the
machine to reach steady-state operating conditions.
[0017] The operations listed above, must be performed (some
manually and others semiautomatically, for example, by jogging the
machine) in a well-defined order constituting a rigid procedure
that must be followed for machine setup to be as quick and
effective as possible.
[0018] Procedures of this kind as guides for machine users are
extremely useful tools which greatly simplify changeover operations
compared to the situation existing prior to their advent.
[0019] However, manual operations or operations that must be
performed under human supervision introduce a certain degree of
unpredictability that may nullify these benefits. Thus, positive
results may not be attained simply on account of the operator's
failing to follow a procedure exactly, either deliberately or due
to negligence, or, for any reason, incorrectly performing, or
dedicating too much time to, one or more of the steps in the
procedure, meaning that the time taken to set up and restart the
machine may become unduly long, with obvious negative repercussions
on production costs and scheduling.
SUMMARY OF THE INVENTION
[0020] In order to improve on this state of affairs, the invention
has for an aim to provide a method that automates the changeover
procedure to a much greater extent than prior art solutions and
significantly reduces the number of operations that have to be
performed manually.
[0021] According to the invention, this aim is achieved through a
method for stopping and restarting an automatic machine for
wrapping products, in particular rolls of toilet or kitchen paper,
in a collective pack using a packaging film unwound from a first
reel, the method comprising the following automatic sequence of
steps, triggered by the activation of a machine stop control:
[0022] reducing machine speed to a speed suitably lower than the
working speed;
[0023] stopping the infeed of the products to the machine;
[0024] stopping the infeed of the wrapping film to the machine with
a delay of at least four steps after stopping product infeed;
[0025] stopping the machine after the products inside the machine
have moved at least three steps forward;
[0026] the method further comprising the steps of
[0027] substituting the first reel of wrapping film with a second
reel;
[0028] loading the film on the second reel into the related film
feed means;
[0029] restarting the machine and thereby automatically activating
the following sequence of steps:
[0030] restarting wrapping film unwinding from the second reel;
[0031] positionally centering the wrapping film;
[0032] restarting the machine at a reduced speed, lower than the
working speed;
[0033] restarting product infeed;
[0034] restarting the infeed of the sheets of wrapping film to the
machine with a delay of at least four steps after restarting
product infeed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The technical characteristics of the invention, with
reference to the above aims, are clearly described in the claims
below and its advantages are apparent from the detailed description
which follows, with reference to the accompanying drawings which
illustrate a preferred embodiment of the invention provided merely
by way of example without restricting the scope of the inventive
concept, and in which:
[0036] FIGS. 1 and 2 are, respectively, an elevation view and a top
plan view of a wrapping machine, represented schematically;
[0037] FIG. 2ais a perspective view of a product pack that can be
made using the machine illustrated in FIGS. 1 and 2;
[0038] FIG. 3 is an elevation view of a part of the machine,
showing a non-restricting embodiment of the means for feeding the
products to the wrapping machine;
[0039] FIG. 4 is a schematic side view of a part of the machine
illustrated in FIGS. 1 and 2;
[0040] FIG. 5 illustrates a first alternative embodiment of the
machine of FIG. 1;
[0041] FIG. 6 is a detail view of a part of the machine of FIG. 1,
showing a non-restricting embodiment of the means for feeding the
wrapping film to the wrapping machine;
[0042] FIG. 7 is a top plan view of the feed means of FIG. 6,
represented schematically with some parts cut away in order to
better illustrate others;
[0043] FIGS. 8a and 8b are block diagrams representing a preferred
embodiment of a procedure for stopping and restarting the machine
of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0044] With reference to FIGS. 1 and 2, the numeral 1 denotes in
its entirety a conventional automatic wrapping machine designed to
wrap products 2, especially rolls of toilet or kitchen paper, in
groups illustrated by way of example in FIG. 2a--where the products
2 are grouped together in a pack and collectively wrapped in a
wrapping 3 made using a film 4 of packaging material suitably
folded and sealed by the machine 1.
[0045] The machine 1--known from Italian patent No. 1.299.896 of
Mar. 04, 2000 (application No.BO98A000149 dated Dec. 03, 1998) to
the same Applicant as the present--essentially comprises: a machine
body labeled 8 in its entirety; product feed means labeled 9 in
their entirety; and means, labeled 10, for feeding the wrapping
film.
[0046] The machine body is shaped substantially like a
parallelepiped, delimited by two plane vertical parallel sides 11
and associated, on one side, with the product feed means 9 and, on
the other side, with the wrapping film feed means 10.
[0047] The sides 11 of the machine body 8--FIG. 4--enclose an
apparatus 12 for mechanically conveying the products 2 in steps
between a series of operating stations in which the process for
wrapping the products 2 and sealing the wrapping 3 is
performed.
[0048] More specifically, the apparatus 12 comprises a pair of
endless chains 13 looped around a pair of pulleys 14, one of which
is power driven. The chains 13 mount a number of pushing elements
15, which project transversely from the chains 13 at regular
intervals longitudinally along the chains 13.
[0049] An elevator 16, equipped with a horizontal loading table 16,
is located inside the machine body 8, below the sides 11, and is
reciprocatingly movable in a vertical direction between a lowered
position, in which it receives the products 2, and a raised
position, in which the products 2 are transferred.
[0050] When the loading table 17 of the elevator 16 is at its
lowered position, the product 2 feed means 9 stack the products 2
on it. When the loading table 17 of the elevator 16 is at its
raised position, it places the products 2 between pairs of
consecutive pushers 15 on the apparatus 12 above it for
mechanically conveying the products 2.
[0051] During the upstroke between the limit positions just
described, the products 2 intercept sheets 18 of wrapping material
positioned horizontally at appropriate intervals across the
vertical path of the products 2 carried by the loading table 17 of
the elevator 16.
[0052] As it moves upwards, the group of products 2 stacked on the
loading table 17 of the elevator 16 thus captures the sheet 18 of
wrapping material which covers the top and sides of the products 2.
On reaching the mechanical conveying apparatus 12, the group of
products 2 and the sheet 18 of wrapping material over it are
transferred to it in a manner that is well within the knowledge of
a person skilled in the trade and that is not described since it
does not form part of the invention, after which the loading table
17 of the elevator 16 moves back down to the lowered position,
ready to receive another group of products 2 and to repeat its work
cycle.
[0053] FIG. 3 shows a preferred, non-restricting embodiment of the
product 2 feed means 9 [this embodiment being known from Italian
patent No. 1.309.317 of Jan. 22, 2002--application No. BO99A000368
dated Jul. 02, 1999--to the same Applicant as the present]. These
feed means 9 comprise a set of endless conveyor belts 19, 20 and 21
which, starting from the machine body 8 and in a direction away
from it, that is to say, in a direction opposite the product 2 feed
direction, comprise: a first pair of short parallel horizontal
belts 19 placed one over the other; a central belt 20 mounted
rotatably in a vertical plane in such a way that it can swing and
thus align its outfeed end 22 to one or the other of the parallel
belts 19; and a fixed horizontal conveyor belt 21 aligned with the
infeed end 23 of the central belt 20.
[0054] Thanks to escapement means 24 and 25 associated with the
central belt 20 and with the belt 21 that precedes it, a local
control apparatus labeled 27 acting in conjunction with suitable
sensors 26, keeps the parallel belts 19 and, hence, the loading
table 17 of the elevator 16 supplied with products.
[0055] FIG. 6 shows a preferred, non-restricting embodiment of the
wrapping film feed means 10. This embodiment, which is disclosed in
Italian patent No. 1.299.896 to the same Applicant as the present,
comprises: a unit 30 for unwinding a film 4 of plastic
material--preferably polythene--from a reel 31; a cutting device
32; a film transporting apparatus 33; and an apparatus 34 for
positioning the sheets 18 cut from the film 4.
[0056] The unwinding unit 30 comprises a pair of unwinding rollers
35 mounted on both sides of the film 4, in contact along their
generatrix, and power driven in such a way as to impart on the film
4 a feed motion that unwinds it from the reel 31.
[0057] A photocell 36 associated with the unwinding unit 30
upstream of the unwinding rollers 35 detects reference marks 70
printed on the film 4 unwound from the reel 31 so that the film is
cut in the desired lengths.
[0058] The unwinding rollers 35 are power driven preferably by an
electronic brushless motor 75--see FIG. 7--which is activated by a
centralized unit 200 that controls the machine 1 in its entirety
for the time needed to unwind a defined length of the film 4, the
length being detected by the photocell 36.
[0059] Between the unwinding rollers 35 and the reel 31, the
unwinding unit 30 includes means 37 for controlled tensioning of
the film 4, which, more specifically, include fixed transfer
rollers 66 and a mobile transfer (dandy) roller 38 mounted on a
linear actuator and slidably housed in a linear guide 39.
[0060] The movements of the transfer roller 38 along the guide 39
are potentiometrically controlled, which means that the tensioning
of the film 4 can be modulated via software by the machine 1
control means according to the physical and geometrical properties
of the film 4 being used.
[0061] The cutting device 32 comprises two knives 40 and 41
embodied as blades oriented transversely to and positioned on both
sides of, the film 4, and one of which has a serrated cutting
edge.
[0062] The first knife 40 is mounted on a roller 42 that is
rotationally driven by an electronic brushless motor 43 that
transmits motion to the roller 42 through a belt 44.
[0063] The second knife 41 is mounted on a support 45 tangentially
to the cutting plane of the first knife 40.
[0064] The cutting device 32 applies a perforated tear line to the
film 4 which does not break the continuity of the film 4 but makes
it easier to tear it into wrapping sheets 18 of suitable size at a
later stage.
[0065] As shown in FIG. 6, adjustment of the cutting device 32 in
order to vary the distance between two consecutive tear lines can
easily be controlled through the centralized control means 200 of
the machine 1 by setting a suitable correlation between the
rotation speed of the first knife 40 and the feed speed of the film
4 being unwound. Thus, the faster the speed at which the film 4 is
fed, the longer the wrapping sheets 18 will be for each full turn
of the knife 40.
[0066] The film transporting apparatus 33 comprises two opposite
transporters equipped with respective power-driven endless belts
46, 47 looped around pulleys 48 and 49 mounted in such a way as to
confer on the belts 46, 47 an elongated annular configuration along
the film 4.
[0067] The belts 46, 47 have transporting sections 50, 51 which
bilaterally grip the interposed film 4, causing it to move from an
infeed area close to the cutting device 32 towards an outfeed area
close to the positioning apparatus 34.
[0068] The transporting sections 50 and 51 of the belts 46 and 47
are opposed from the inside of the respective annular
configurations by a series of presser rollers 52 and 53 mounted on
supports 54.
[0069] The presser rollers 52 and 53 are offset from each other
lengthways along the film 4 and are mounted in such a way as to
interfere at right angles to the transporting sections 50 and 51 so
as to confer on the film 4 a longitudinally undulated form designed
to facilitate feeding of the film 4 by friction.
[0070] The belts 46 and 47 just described constitute guide means
designed to make the film 4 move in a direction of feed indicated
in FIG. 7 by an arrow 78.
[0071] The positioning apparatus 34--FIG. 6--extends in line with
the transporting apparatus 33 and goes through the machine body 8
below the sides 11.
[0072] Looking in more detail, the positioning apparatus 34
comprises two opposite power driven endless belts 55 and 56 wound
around pulleys 57, 58 to form horizontally elongated loops
lengthways along the film 4.
[0073] The belts 55 and 56 are opposite each other at transporting
sections 59, 60 which are pressed against each other from both
sides of the film 4 by rollers 61, 62 in such a way as to make it
move along horizontally until it reaches the vertical path of the
elevator 16.
[0074] The belts 55 and 56--which also embody means for guiding the
film 4--are power driven by a motor 63 and move at a variable
speed, tangential to the film 4, that may be much higher than the
speed of the film 4 along the transporting apparatus 33 which, on
the contrary, moves at a constant speed. The lower belt 56 is
supported by a four-bar linkage 71 driven by a motor 64. The
driving action of the motor 64 enables the linkage 71 to move the
lower belt 56 away from the upper belt 55 so as to slacken the hold
which the two belts 55 and 56 have on the film 4.
[0075] By accelerating the belts 55, 56 of the positioning
apparatus 34 relative to the belts 46 and 47 of the transporting
apparatus 33, the film 4 is torn into sheets 18, each delimited by
two consecutive tear lines, at the zones where the film 4 is held
simultaneously both by the belts 46 and 47 of the transporting
apparatus 33 and by the belts 55 and 56 of the positioning
apparatus 34. Each sheet torn off the film 4 is carried by the
positioning apparatus 34 as far as the vertical path of the
elevator 16, whereupon the motor 63 that drives the positioning
apparatus 34 is stopped.
[0076] Next, the four-bar linkage 71, driven by the motor 64, moves
the lower belt 56 away from the upper belt 55, and the sheet of
film released from the hold of these two belts, is: intercepted by
the pack of products 2 being lifted by the elevator 16; pulled out
of the positioning apparatus 34; and finally transferred, together
with the products 2, to the part of the machine body 8 above, where
the remaining steps of the wrapping cycle are carried out.
[0077] In order to be able to process film 4 of different sizes, as
shown in FIG. 7, the successive pairs of belts 46, 47 and 56,
57--belonging to the transporting apparatus 33 and to the
positioning apparatus 34, respectively--are designed to allow the
distance between the pairs of belts to be varied in a direction 77
transversal to the film 4 feed direction 78.
[0078] A comparison between FIGS. 1 and 5 reveals that, in the
embodiment illustrated in FIG. 1, a depleted film reel 31 can be
substituted manually by removing the reel 31 from its bracket 73
and mounting a substitute reel 31 in its place, whereas the
alternative embodiment illustrated in FIG. 5 features an apparatus
6 especially designed to substitute the reel fully
automatically.
[0079] For this purpose, the apparatus 6, which is per se well
known to experts in the trade, comprises two reels 31a and 31b; a
work head 74 divided into two parts operatively associated to the
films 4a, 4b unwound from the two reels 31a, 31b, respectively; and
transfer means 76 which connect the film 4 feeding out of the work
head 74 to the means 10 that feed the film 4 to the machine 1.
[0080] Below is a brief description of the way the automatic
apparatus 6 works. When the film 4a on one of the reels, for
example the lower reel 31a, is nearly finished, a suitable exchange
of signals between the reel 31a and the controller of the work head
74 triggers the part of the work head 74 associated with the film
4b on the upper reel 31b in order to attach the front end of the
substitute film 4b with bi-adhesive tape to the trailing end of the
depleted film 4a; after which the work head 74 cuts the film 4a
from the reel 31a and feeding of the film 4 continues from the
upper reel 31b.
[0081] The transfer means 76 create a sort of reservoir enabling
the film 4 to continue feeding to the machine 1 without
interruption and without reducing the speed at which the film 4 is
fed.
[0082] The machine 1, whose general structure is outlined above,
can be used to implement a stopping and restarting
procedure--allowing rapid changeover to products of a different
size, that is to say, changing the wrapping film in an extremely
simple manner that minimizes down time--which, in a first preferred
embodiment schematically represented in the block diagrams of FIGS.
8a and 8b, comprises the following steps:
[0083] stopping production with the machine [block 80] through a
command issued manually by the operator from a suitable control
panel; this command having the effect of triggering a
sub-program--labeled 100--residing, for example, in the means 200
for controlling the machine 1, and designed to perform the
following steps fully automatically:
[0084] reducing the speed of the machine 1 [block 81] from
production speed V1 to an appreciably lower speed, for example, to
a speed V2 of around 20 cm/min;
[0085] stopping the means 9 for feeding the products 2 [block 82]
with a delay, after reducing machine speed as just mentioned, of
4-5 steps of the conveying apparatus 12 continuing to feed the
products 2 within the machine body 8; and
[0086] stopping film 4a feed, that is to say, stopping the motor 75
that unwinds and feeds the film 4a in the transporting apparatus 33
[block 83]; this stop being effected with a delay of 3-4 steps of
the conveying apparatus 12 continuing to feed the products 2;
[0087] Once this sub-program has been completed [block 100] the
procedure returns to the direct control of the operator, who:
[0088] stops the machine 1; and proceeds to
[0089] manually changing the reel 31a with a reel 31b of substitute
film 4b [block 85];
[0090] adjusting the distance between the guide means 46, 47 and
55, 56 of the transporting apparatus 33 and of the positioning
apparatus 34 to the size of the substitute film 4b [block 86];
[0091] manually inserting the substitute film 4b [block 87] between
the unwinding rollers 35 of the film transporting apparatus 33;
and
[0092] manually restarting the machine [block 88]; the start
command also starting a second automatic sub-program 150, also
residing in the means 200 that control the machine 1.
[0093] The second sub-program 150 performs the following steps:
[0094] starting the automatic unwinding of the substitute film 4b
[block 89];
[0095] positionally centering the references 70 of the substitute
film 4b [block 90];
[0096] restarting the machine 1 at low speed V2 [block 91], for
example, again approximately 20 cm/min;
[0097] restarting the product feed means 9 [block 92]; and
[0098] starting the feeding of the film 4b [block 93] with a delay
of 4-5 cycles after restarting product feed.
[0099] Once the second sub-program 150 has been completed, the
procedure returns once again to the control of the operator who
performs a few product 2 wrapping cycles in manual mode at low
speed V2 [block 94] in order to check that the entire system is
functional and ready to resume work at production speed V1.
[0100] Compared to prior art, the procedure described above
significantly reduces the number of steps that need to be carried
out manually, passing from 11 steps to just 4 steps, with obvious
advantages in terms of reduced down time, since the procedure is
performed more quickly, and with less chance of human error.
[0101] However, by varying the structure of the machine 1 according
to the embodiment illustrated in FIG. 5, the procedure can be
simplified even further, with a further reduction in the number of
steps to be carried out manually, so that, returning to the block
diagram of FIG. 8a, it is at once clear that the apparatus 6 for
automatically substituting the film 4a with the film 4b makes it
possible to: perform automatically the steps of substituting the
reel 31a with the reel 31b [block 85] and of inserting the film 4b
between the unwinding rollers 35 of the transporting apparatus 33
[block 87].
[0102] Moreover, if the changeover to another product does not
involve changing the wrapping film 4a with a wrapping film 4b of a
different width, assuming for example, that the new packs to be
made can be wrapped with the same film by simply changing the
length of the sheets 18, then the steps of adjusting the guide
means of the 46, 47, 55, 56 of the transporting apparatus 33 and of
the positioning apparatus 34 [block 86] can be dispensed with.
[0103] That means a further reduction in the number of operations
to be performed manually, reducing the operator's task to simply
starting some of the steps in the automatic procedure and checking
that the procedure is carried out correctly.
[0104] In this case, however, there remains the disadvantage of
having to continue to use wrapping film of the same width, which,
although it allows packaging of a certain number of different types
of packs, means that the procedure does not apply to a changeover
where the new product necessarily involves use of a wrapping film
having a different width.
[0105] Thus, in such a case, it is evident (see FIG. 7 and block
diagrams of FIGS. 8a and 8b] that once the first sub-program 100
and block 84 have been completed, the performance of block 85 by
the operator involves not only changing the first film reel 31a
with a second substitute reel 31b, but also manually splicing the
substitute film 4b to the previous film 4a and cutting the
protruding edges created by the different width of the two spliced
films 4a and 4b. At this point, the performance of block 86 by the
operator involves manually adjusting the distance between the guide
means 46, 47 and 55, 56: first of the transporting apparatus 33 and
then of the positioning apparatus 34; manually pulling the film 4a
to be substituted until the substitute film of different width is
securely held by the belts 46, 47 and 55, 56 of the transporting
apparatus 33 and of the positioning apparatus 34; after which the
sub-program 150 can finally be started in order to complete the
procedure according to the block diagrams of FIGS. 8a and 8b.
[0106] In order to overcome this drawback, the procedure according
to the invention can be further improved by providing the
transporting apparatus 33 and the positioning apparatus 34 of the
film 4 with suitable drive motors and by controlling these motors
in a suitable manner.
[0107] Thus, assuming that the operator has performed the cycle
illustrated in FIGS. 8a and 8b from the initial block 80 through to
block 85 in exactly the same way as described above, that is to
say, assuming that the operator has already: manually changed the
reel 31a with the reel 31b; manually spliced the film 4a to the
substitute film 4b using bi-adhesive tape to attach the trailing
end of the former to the front end of the latter; and manually cut
the corners of the wider film where it is spliced to the narrower
film; and assuming that the motors 63 and 75 that drive the drive
pulleys 35 and 57 of the film transporting apparatus 33 of the film
sheet positioning apparatus 34--that is to say, the pulleys that
drive the rollers connected to them--can be disengaged from the
film by suitable clutches, the operator can turn film feed drive on
and off and jog the motors 63 and 75 in such a way as to feed the
two spliced films 4a and 4b along the feed path 78 without manually
operating on them.
[0108] Thus, the operator can operate the two motors 63 and 75
normally until the splicing line 65 between the two films 4a and 4b
is in the proximity of the transporting apparatus 33 [FIG. 7]. At
this point, by acting on the clutch of the motor 75 in such a way
as to disengage the guide means 46 and 47 of the transporting means
33 from the film 4a, the guide means themselves can be moved
transversely to the feed direction 78 of the film 4a, 4b so as to
adjust the distance between them according to the width of the
substitute film 4b. By doing this, the drive motion used to feed
the two spliced films 4a and 4b is provided entirely by the motor
63 of the positioning apparatus 34. Under these conditions, the two
spliced films 4a and 4b are fed forward until the splicing line 65
between them reaches the infeed end of the positioning apparatus
34.
[0109] At this point, after disengaging the two drive motors 63 and
75 of the two films 4a and 4b by acting on their clutches, it is
possible to adjust the distance of the positioning apparatus 34
guide means, that is to say, the distance between the belts 55 and
56, according to the width of the film 4b. The film 4a to be
substituted is thus disengaged from the belts 55 and 56, whilst the
substitute film 4b behind it is simultaneously held both by the
transporting apparatus 33 and by the positioning apparatus 34.
Since the tear line, which has in the meantime been made by the
knives 40 and 41 as the spliced films 4a and 4b move forward
together, is certainly located at the positioning apparatus 34, it
is possible to manually tear off the film 4a to be substituted
which has in the meantime been disengaged from the guide means 55
and 56, leaving only the substitute film 4b, which is by this time
well inserted between the drive pulleys 57 and 58 of the sheet
positioning apparatus 34 ready for the wrapping cycle to be
continued.
[0110] At this point, the operator can resume the procedure from
block 88 and start the second automatic sub-program 150 as
described above.
[0111] Thus, the method just described eliminates the need for all
the manual steps of adjusting the width of the film transporting
apparatus 33 and of the film sheet 18 positioning apparatus 34 and
of loading the substitute film 4b.
[0112] The invention described has evident industrial applications
and can be subject to modifications and variations without thereby
departing from the scope of the inventive concept.
[0113] In this connection, it should be stressed that yet another
improvement to the invention in order to further automate the
procedure can be made by setting a suitable correlation between the
current position of the splicing line 65 between the two films 4a,
4b and the adjustment of the transporting apparatus 33 and of the
positioning apparatus 34.
[0114] Thus, by implementing a control system capable of
automatically reading the current position of the splicing line 65
relative to a predetermined reference system, and establishing a
relation between this control system and the machine control means
200 in such a way as to issue signals for driving the actuators of
the guide means 33, 34, 55, 56 of the film 4a, 4b, it is possible
to fully automate the adjustment operations so that adjustment is
remotely controlled in process when the splicing line 65 reaches
certain defined positions along the feed path 78 of the film 4a,
4b.
* * * * *