Wrapping machine, particularly for blister packs and the like, with synchronized plural driving means

A wrapping machine for making blister packs has two machine sections for the formation of a continuous strip of blister packs by means of a stamping operation on a thermoplastic tape and for the separation of the individual blisters from the strip for the packaging thereof. Each of the machine sections is provided with its own drive which is phase-synchronized with the pilot motor of the downstream machine section effecting the separation of the individual blister packs from the continuous strip of blister packs and their packaging and the motors controlled by the stamping elements of the upstream machine section which forms the continuous blister pack strip.

FIELD OF THE INVENTION 
The present invention relates to a wrapping machine, and more particularly 
to a machine for making blister packs and the like with synchronised 
plural driving means. 
BACKGROUND OF THE INVENTION 
It is known that in wrapping machines, particularly in automatic machines 
of the cyclical type, which have very complex structures and operations, 
the single finished product discharged by such a machine is the result of 
numerous and complex operations carried out by a variety of elements 
(feeding means for the wrapping material and for the product to be 
wrapped, transport means, sectioning means, etc.). 
Each of these elements has a specific operational cycle and deriving its 
movement (continuous, intermittent, alternating, etc.,) from a common 
source, consisting, for example, of a continuously driven rotating shaft, 
operated directly or through mechanical connection means by the drive 
motor of the machine. 
These operations are obviously carried out according to a well-defined 
sequence and as a function of the precise and constant relationships 
between the operating cycles of the elements. The accurate timing of these 
phase relationships guarantees, in addition to a proper functioning of the 
machine, the output of faultless finished products. These phase 
relationships are, as a rule, depicted within the totality of the by 
graphs representing the laws of motion of each of the cyclically operating 
elements, sketched with respect to a common reference, in particular as a 
function of the angular position, measured in degrees from a predetermined 
"null position" of the said continuously rotating shaft which is normally 
referred to as the "cycle shaft" while the term "machine cycle" or cycle 
alone refers to one rotation of said shaft through 360.degree. from the 
aforesaid "null position". 
These machines make extensive use of elements which are being associated 
with control and detector means of various types and are intended to 
intervene in the the production process either sporadically or 
periodically, but at a much lower frequency relative to the previously 
mentioned elements. Among these there may be mentioned for example the 
devices provided for periodically replacing the roll of packaging material 
as it is being exhausted, the devices for rejecting incomplete or poorly 
completed products, etc. 
As a consequence, as these last-mentioned elements are usually at rest, 
their actions are effected by means of independent motors or are derived 
from the driving means of the machine only when so commanded by the said 
control or detector means, which intervention has to take place in 
consideration of the precise phase relationship appropriate to the laws 
which govern the intervention of the cyclically operating elements, as 
mentioned previously. To illustrate this, I mention the case of an ejector 
which, having to eject a defective product from an intermittently moving 
transport means, has to wait until the latter is at rest. 
Furthermore, as is known, the phase coordination between the elements which 
intervene normally in the various productive operations and the 
intermittently operating elements is obtained by means of the "cycle 
shaft" and, more specifically, concurrently with the actuation of the last 
mentioned means, the functioning of which is already dependent on the 
operation of the control and detector means the coordination is effected, 
in relation to the given phase, by means linked with this cycle shaft 
electromechanically or, in the case of complex high-speed production 
machines, electronically. 
Referring now particularly to the blister-pack producing wrapping machines 
which are known, the blisters are obtained in a continuous strip, by 
conveying along the operating track of the machine a strip of 
thermoplastic material unrolling from a roll and subjected to a series of 
successive operations along the operating track at the corresponding work 
stations of the wrapping machine. 
Thus, for example, in a well-known blister-pack producing machine, 
manufactured and sold by the assignee of this application under the Trade 
Mark IMA C 60, the strip of thermoplastic material is substantially first 
subjected to a differential heating and then to the action of pressing 
means to stamp into the strip thus preheated lodgings or cells (blisters) 
for containing the individual products to be wrapped. The blister-carrying 
strip thus constituted, in its movement along the operating line of the 
wrapping machine, passes through a feeder station for the products to be 
wrapped, which products are lodged one by one successively into said cells 
and, subsequently. through a station for closure by hermetical sealing of 
the said blisters, each of which contains one of the products to be 
wrapped. 
The sealing is effected by the superposition on said strip of thermoplastic 
material thus formed and thus filled with the products to be wrapped, a 
second strip, usually made of aluminum, weldable to the first strip of 
thermoplastic material, obtaining in this manner the aforesaid continuous 
strip of blister packs. 
Finally, the continuous trip of blister packs thus obtained is either fed 
to a further machine for subsequent treatments prior to the separating and 
packaging operations or is caused to pass through a separating station of 
the same machine where, by sectioning, the individual blisters are 
separated rhythmically and successively. The blisters are stacked for 
introduction, at the end of the production cycle, into container cases or 
are fed in succession to another packaging machine. 
The advancing movement of the strip along the operating line of this 
wrapping machine IMA C 60 is effected in a continuous mode up to the 
hermetically sealing closure section where the blisters are sealed by 
means of one or more drawing rollers disposed correspondingly to said 
closure station so as to operate from a counter-roller a thermal welding 
roller to effect the hermetically thermal welding of the two superimposed 
strips, and in intermittent mode or by successive passes in the 
predetermined case of its immediate separation into individual successive 
blisters between these two respective stations of closure and separation. 
These machines for making blister, having an integrated operating line and 
operating with continuous movement in the machine section dedicated to the 
preparation of a continuous strip of blister packs and with intermittent 
movement in the machine section effecting the separation of the individual 
blister packs from the said continuous strip and for the packaging of said 
individual blister-packs singly or in groups in boxes or cases, derive 
these movements from a single common source, that is to say a single, 
continuously rotating shaft, called "cycle shaft". 
Such machines yield optimum results from the point of view of product 
quality and productivity per unit of time, and at high speed. They are 
referred to in the trade jargon as rigid machines because of the common 
source of the two movements, continuous and intermittent, of the two 
machine sections, and also because in order to vary the dimensions of the 
finished product it is necessary to change the so-called "shaping" 
elements or pieces of the machine. 
OBJECT OF THE INVENTION 
It is the object of the invention to provide a wrapping machine for making 
up blister packs of this known type having an improved operational 
flexibility without substantially changing the size and capacity, and 
which can operate at an improved production rate per unit of time, while 
being universal with regard to variations in product dimensions. 
SUMMARY OF THE INVENTION 
This object is attained, according to the invention for the two distinct 
machine sections of the above-named type, in that the upstream machine 
section, with continuous movement for the formation of the continuous 
strip of blister packs, and the downstream machine section, with 
intermittent movement for the separation from the continuous strip of the 
individual blisters and the packaging of the latter in boxes or cases, are 
caused to invert their movement specifically at the station where the 
blisters are formed by stamping in the continuous strip of thermoplastic 
material, of the corresponding machine section, by providing it with its 
own driving means, as well as adopting the conventional solution which 
provides for a common driving means traditionally employed, providing for 
a plural synchronized drive, and operating further on the mechanical 
structure of these two machine sections. 
More particularly, the motor serving to drive the downstream machine 
section for separating from the continuous strip the individual blister 
packs and for packing the latter into boxes and cases will be referred to 
as the "lead drive." The motor which drives the elements of the stamping 
station of the intermittently moving upstream section is referred to as 
the follower drive. The motors are linked to respective actuating 
apparatuses. The first motor is provided with a device (a potentiometer) 
to determine the speed of said main drive, and is associated with a coding 
device generating incremental pulses (encoder) which acts on a device for 
converting the frequency of the respective incremental pulses into an 
analog signal proportional to the speed of the lead drive. The analog 
signal is applied to a comparator. The second motor, which is associated 
with the follower drive, is similarly provided with an encoder connected 
to the comparator, the outputs of said converter and comparator 
controlling the actuating apparatus of the follower drive. 
The upstream machine section involved in intermittent movement has its 
press parts for stamping out the lodgings (blisters) of the strip of 
thermoplastic material underneath the unit feeding in the products to be 
conditioned in said blisters, creating upstream and downstream of the 
stamping portion, respectively, loops and bends in the strip, constantly 
controlled by controlling devices in a manner independent of the 
synchronization between the two motors. The downstream machine section 
operating with continuous movement effecting the separation from the 
continuous strip of the individual blister packs and the packing of the 
latter in boxes or cases, enables that the separation and the transport of 
the individual blister packs to be effected in multiple parallel rows 
terminating in their introduction in boxes or cases. 
The blister pack forming machine of the invention comprises a 
blister-forming stamping station for a first continuous strip of 
thermoplastic material, a feeder station for the products to be enclosed 
in the blisters, a station for effecting the closure and hermetically 
sealing of the products in the blisters by the superposition of a second 
continuous strip on said first strip of thermoplastic material thus shaped 
and thus fed with the the said products to be packaged, a station for 
separating the individual blister packs thus obtained and stacking them in 
desired numbers, a station for associating therewith an element indicating 
the condition of the individual or stacked blister packs, and a station 
for packing the blisters or blister stacks in boxes or cases in 
association with the element indicating the condition of the product. 
According to the invention the stamping station is located underneath the 
feeder station and its stamping elements are actuated by a follower motor 
controlled by a lead motor which actuates the elements of the other 
stations the motors being acted upon by respective actuator devices of 
which the one controlling the lead motor is in turn controlled by a device 
for determining the desired speed of the lead motor. 
The lead and follower motors are associated with corresponding coding 
devices generating incremental impulses (encoders). The first encoder, 
that which is associated with the lead motor, feeds a device for 
converting the frequency of the respective incremental pulses into an 
analog signal proportional to the speed of the lead motor and a comparator 
device. The second encoder, which is associated with the follower motor, 
feeds a signal to the same comparator device. The outputs of the converter 
and comparator control the actuating device of the aforesaid follower 
motor. 
The said separator and stacking stations also carry out the transport 
operation in multiple parallel rows to the station associating the 
products with the element indicating the condition of the products and 
hence to the station for packing same into boxes or cases.

SUMMARY OF THE INVENTION 
A continuous strip 1 of blister packs is formed and separated into 
individual blister packs. The stacking and transport of the individual 
blister packs for packaging in boxes or cases, is likewise effected in the 
machine. The continuous strip of blister packs (see FIGS. 1A, 1B, 2A, 2B 
and 3) is obtained essentially by feeding along the horizontal operating 
line of the machine a strip 2 of thermoplastic material drawn from a roll 
3. 
The strip 2 is subjected to a series of operations along the operating line 
of the machine in accordance with the number of operational stations of 
the machine. 
First the strip is subjected at a station A to the action of stamping means 
to form, in transversal and longitudinal alignment, by stamping in said 
strip 2, lodgings (blisters) 4 to contain the individual products to be 
packed. The strip is drawn by drawing rollers 5, 6 through a station B for 
feeding into the blisters, the products to be contained therein, then 
through a station C which effects the closure by hermetical sealing of the 
said blisters 4, each containing one product to be packed, by the 
superposition on the strip 2 of thermoplastic material, a second strip 7, 
usually of aluminum, weldable to the thermoplastic material strip 2, thus 
obtaining a continuous strip 1 of blister packs. 
The continuous strip of blister packs 1 then reaches a station D of the 
machine, at which location cutting means rhythmically separate the 
individual blister packs which, optionally stacked in a desired number. 
arrive, on completion of the operating cycle, at a station F, to be set 
into containers, having first passed through a station E which has an 
element detecting the condition of the packed product associated with it. 
In the wrapping machine according to the present invention, the stamping 
means 8 for stamping blisters 4 in the strip of thermoplastic material 2 
at station A are arranged underneath the feeder elements 9 of station B, 
creating, in said strip 2, upstream and downstream of said stamping means 
8, respective loops and bends 10, 11 constantly controlled by 
corresponding control devices 12, 13 and, immediately downstream of said 
closure station C, it is structured to operate in correspondence with the 
station D effecting the separation of the strip 1 into individual blister 
packs and in correspondence with station G for the stacking of said 
individual blister packs, in the form of multiple parallel rows to the 
station I where these are aligned in a single file (see the concurrently 
filed commonly assigned patent application Ser. No. 07/116,484 filed 2 
Nov. 1987) in order to pass through the aforementioned stations E and F. 
A machine thus constructed according to the present invention is provided 
with plural synchronized driving means so as to cause the strip 2 to 
advance through the station A with intermittent movement or successive 
passes to effect the stamping of blisters 4 by the aforesaid stamping 
means 8, to advance the strip 2 thus provided with blisters 4 through the 
station B to feed into said blisters the products to be conditioned and 
through the station C for closure by sealing said products into said 
blisters in a continuous movement, forming loops or bends 14 controlled by 
a control device 15 in a manner independent of the synchronised plural 
driving means being the object of the present invention, to the station D 
effecting the division of the continuous strip 1 of blister packs into 
individual blister packs 1a, 1b in multiple parallel rows and hence, see 
the aforesaid patent application, through the aforementioned stations, G 
for stacking, I for alignment in a single file and the above mentioned 
conditioning stations E and F. 
Such a plural synchronised motorization according to the present invention 
comprises, see FIG. 4, a motor 16, called the leader motor, for driving 
the downstream machine section for the separation from the continuous 
strip 1 of the individual blister packs 1a, 1b and for the packaging of 
the latter in boxes or cases, and a motor 17, called the follower motor, 
for driving the elements of the stamping station A of the upstream machine 
section. The motors 16 and 17 are subject to the action of respective 
actuator means actuator 18 and 19, of which the one, 18, acting on the 
leader motor 16, is in turn acted upon by a device 20 (potentiometer) for 
determining the desired speed of this leader motor 16. 
With the leader motor 16 and follower motor 17, there is associated a 
respective corresponding coding device 21, 22 generating incremental 
pulses (encoder) of which the first encoder 21, acted on by the leader 
motor 16, controls a device 23 for converting the frequency of the 
respective incremental pulses into an analog signal proportional to the 
leader motor 16 and a comparator device 24, and the second encoder 22 and 
associated with the follower motor 17, acts on the same comparator device 
24. The outputs of the said converter 23 and comparator 24 devices further 
control the actuator device 19 of the aforesaid follower motor 17.