Method for thermoforming and stacking hollow objects

A method for the thermoforming of hollow objects having a base from a sheet of thermoplastics material, which effects in one single predetermined operating cycle, the production of a pressed object by hot forming and cutting out of the object or objects between one half of a movable double female mould which is located in the forming area opposite a male die, movement of the female half of the mould, said half containing therewithin the thermoformed object or objects, towards a corresponding discharge area alternately to one side or the other of the forming area, picking up the object or objects from the female half of the mould located in corresponding discharge area and transferring each object to a plurality of receiving formers of a shape corresponding to the mould, which formers can move sequentially stepwise along a track, sequential movement of the formers to at least one workstation or handling station at the same time as the female mould moves back to place its other half opposite the male die in order to produce a subsequently formed object, and performing at least one processing or handling operation on all the objects carried by at least one former at the same time as the next formed object is produced.

This invention relates to a method and apparatus for the thermoforming of 
hollow cup-shaped objects such as beakers, goblets, cups, tubs and the 
like, from a sheet of thermoplastics material, and their removal from the 
press in which they are produced. 
BACKGROUND OF THE INVENTION 
As is known, so-called "thermoforming" machines, fall into two quite 
separate classes depending upon their method of operation; firstly there 
are thermoforming machines which form and cut the sheet at separate 
workstations and secondly there are machines which form and cut the sheet 
at a single workstation. Such machines are used in the production of 
objects of thermoplastics material, e.g. "disposable" objects, from a 
sheet of hot pressed material. 
This invention relates to a method and apparatus which falls into this 
second class, in that the shaping or forming of objects and their 
separation from the sheet of starting material is effected at a single 
workstation. 
The state of the art for thermoforming methods and apparatus incorporating 
a single forming station, separation from the initial sheet and subsequent 
removal from the press, is represented by conventional single station 
machines and those according to U.S. Pat. No. 4,560,339 which will be 
briefly described hereinafter with reference to FIGS. 1 to 13 of the 
accompanying drawings, in which: 
FIG. 1 is a side view in diagrammatic form of a thermoforming machine 
having an upper male die and a single lower female mould shown in the open 
press position prior to forming; 
FIG. 2 is a side view of the machine of FIG. 1 shown with the press closed 
during the forming stage; 
FIG. 3 is a view similar to that shown in FIG. 2 with the press closed 
during the cutting stage; 
FIG. 3a is a schematic view of a detail of FIG. 3 shown on an enlarged 
scale; 
FIG. 4 is a side view of the machine of FIG. 3 shown with the press open 
after the formed object has been cut out but still remains in the press; 
FIG. 5 is a similar view to that in FIG. 4 but at a subsequent stage in 
which the pressed object is removed from the female mould and removed from 
the pressing area to a stacking collector; 
FIG. 6 is a side view of a variation of the machine shown in FIG. 5 having 
a multiple row of moulds which discharge in bulk to a separate stacker; 
FIGS. 7 to 10 show diagrammatic views of another variation of the machine 
shown in FIG. 5, in which the pressed objects are removed from the 
pressing area by means of a suction plate which can be placed between the 
male and female parts of the press; 
FIG. 11 diagrammatically illustrates a plate which can lift a plurality of 
articles pressed in a single pressing operation by suction, used in the 
machine according to FIGS. 7 to 10; 
FIG. 12 diagrammatically illustrates a front view of a thermoforming 
machine having a single upper male die and a double lower female mould 
which moves alternately beneath the male die; and 
FIG. 13 includes a diagram which illustrates the stages and opening/closing 
cycle times for a thermoforming press having a single female mould. 
The thermoforming cycle in machines which carry out forming and cutting at 
a single workstation can be described schematically as follows. 
Stage 1: Sheet feed with the press open (FIG. 1). 
A portion of sheet material A is delivered from a feed role (not shown) and 
is heated by irradiators B, e.g. infrared sources, and caused to advance 
between the open portions of the press, that is into the thermoforming 
area, in the direction of arrow F. The press consists of an upper male 
part or die M.sub.1 and a lower female part M.sub.2. Both parts M.sub.1 
and M.sub.2 may be single or multiple, in which latter case several 
objects O can be obtained from each pressing operation. 
Stage 2: Forming while the press is closed (FIG. 2). 
The lower female part M.sub.2 rises against fixed male die M.sub.1 and 
object O is hot formed by causing rough shaping die M.sub.1p to enter the 
cavity M.sub.2c of female mould part M.sub.2 and thereafter injecting 
compressed air or applying negative pressure through a hole FO in male die 
M.sub.1. The compressed air causes the material A around rough forming die 
M.sub.1p to adhere to the side wall of cavity M.sub.2c and movable base 
M.sub.2f thereof. Then cavity M.sub.2c is cooled by a water cooling 
circuit generically indicated by C, and object O is also cooled and then 
subjected to a process of progressive structural and dimensional 
stabilisation. 
Stage 3: Cutting (FIGS. 3 and 3a). 
In this stage, all the lower part M.sub.2 of the press moves a distance ST, 
usually 1.5 mm (FIG. 3a) towards upper die M.sub.1, which is sufficient to 
separate the edge BO of object O from starting sheet material A. 
The three stages described above are common to all thermoforming machines 
which shape and cut at a single workstation, or forming area (see diagram 
in FIG. 13). However a distinction is made between two classes of 
thermoforming machines on the basis of the different arrangements used to 
remove thermoformed objects O from the female mould M.sub.2 and subsequent 
operations (counting, stacking, etc.). The former have a single female 
mould M.sub.2, the latter has a double female mould, one on the left 
M.sub.2c and one on the right M.sub.2d, which are integral with each 
other, as will be explained below with reference to FIG. 12 and the object 
of Italian Patent No. 1,073,243. 
The cutting stage (stage 3) completes the closed press cycle of operations 
(FIG. 13). 
After this stage, the lower part M.sub.2 of the press descends, or moves 
away from upper part M.sub.1, following an S-shaped track (FIG. 4) 
carrying with it formed and cut object O, which therefore moves below the 
waste starting material A. Subsequently moving base component M.sub.2f of 
lower mould M.sub.2 ceases its downwards movement while the remaining part 
of mould M.sub.2 continues to move downward, thus drawing out and 
releasing object O completely from cavity M.sub.2c of mould M.sub.2. 
At this point in the cycle there arises the difficult problem of moving or 
removing the thermoformed object or objects O from the forming area and 
stacking them. Various systems have been proposed, and the two most widely 
in use will be described below. 
The first is the air blowing system (FIG. 5) which consists of supplying 
compressed air along a main CL provided with nozzles U which produce jets 
G which lift up objects O, causing them to tip slightly or topple into one 
or more collection channels R. The objects, continuing along collection 
channel R, become stacked forming a stack P. 
This system can however only be used if the objects in mould M.sub.2 are 
arranged in a single file. 
If the objects in mould M.sub.2 are in several rows (multiple files) the 
air jets G may remove objects O from the area bounded by parts M.sub.1 and 
M.sub.2 of the press, but they will be discharged in bulk. In order to get 
these back into order and then stack them, it is necessary to have a 
suitable stacking device PL (FIG. 6), which is separate from the 
thermoforming machine, but whose function must be synchronised therewith. 
This naturally involves heavy additional costs, greater complexity in 
operation and a high percentage of damaged objects which then have to be 
rejected. 
In thermoforming machines provided with a stacker PL, objects O are 
"removed" by blowing them out of the forming area and causing them to 
impact against a stop surface AR before falling into a collecting bin V. 
At the base of collecting bin V there may be provided, as one of a number 
of possible systems, a conveyor belt collector TR controlled by a Maltese 
cross device which has a plurality of panels hinged together, each of 
which has a hole W.sub.1 which houses one object O. After impacting 
against surface AR which is orientated with a well-defined inclination, 
the objects end up by falling into holes W.sub.1 to be then transported 
intermittently towards a pusher I.sub.p controlled by a toggle E which 
pushes them one by one into a collection channel R where they form a stack 
P. 
This system, which is mentioned here by way of example as one of many 
similar types, has many disadvantages. 
To begin with, only circular objects which are taller than particular 
minimum dimensions can be stacked. It is not therefore possible to stack 
objects which are constrained to a specific orientation, e.g. objects of 
rectangular shape. 
Also, in falling and being mixed together in bin V, many objects become 
deformed or otherwise damaged. 
For these reasons the known system illustrated in FIG. 6, and others like 
it, are now considered to be obsolete. 
The second system using a suction plate is illustrated diagrammatically in 
FIG. 7 to 11 and is the object of Italian Patent No. 1,175,178. During the 
opening T of the press, which is effected by lower female mould M.sub.2, a 
suction plate PA is inserted between the upper edge B of thermoformed 
object O, but blow waste A of the starting material, in such a position 
that object or objects O can be sucked up when mould M.sub.2 has finished 
its descent T (press completely open). 
Mould M.sub.2 then stops in its lowest position to allow suction plate PA 
to move away from the area bounded by dies M.sub.1 and M.sub.2 (forming 
area--FIG. 8), carrying with its objects O to an area adjacent to the 
thermoforming machine where they are picked up by suckers VS hinged on 
arms BG of a stacker R (FIGS. 9 and 10). As soon as plate PA reaches the 
position illustrated in FIG. 8, and is therefore outside the forming area, 
mould M.sub.2 begins its upwards movement, sheet material A advances by a 
further step and a new thermoforming cycle is thus initiated. At the same 
time suckers VS (FIG. 9) takes objects O from plate PA. By means of a 
rotation of arm BG and a simultaneous rotation about pin Q suckers VS are 
turned over and carried against a multiple collector R where the objects 
are stacked into stacks P (FIG. 10). 
The difficulties and disadvantages which limit the performance of the 
extraction system in thermoforming machines with a single female mould 
are: 
1. The very long distance T by which the press must open, which is the sum 
of the height of the object or objects O and the distance travelled S 
(FIGS. 4 and 7) plus a specific distance to ensure a reasonable margin of 
safety (FIG. 7). However, as the time used in moving distance T is time 
which is of no use to the cycle it will be understood that, other things 
being equal, the output of the machine will be lower the taller the 
objects O which have to be removed. 
2. Travel S is provided to create the space necessary for plate PA to 
insert itself between material A and thermoformed object or objects O. 
Keeping travel distance S short implies creating problems with the size of 
suction plate PA. Increasing distance S means appreciably lowering the 
productivity of the thermoforming machine. The definition of track S and 
the dimensioning of plate PA are therefore always the result of a 
compromise. However the dimensions of suction plate PA are also governed 
by the requirement that it must not impede the advance of sheet material 
A, which being in a heated state, has a tendency to weaken and fall 
downwards. 
3. Keeping the press open for the time required for suction plate PA to 
enter and leave the forming zone increases the dead time in the 
thermoforming cycle (FIGS. 7, 8 and 13). 
The fact that presses have to stand open for the time required for 
inserting plate PA between material A and object or objects O which have 
to be removed, sucking up the objects and removing them (a time which is 
commonly equal to 30% of the cycle time, i.e. a by no means negligible 
period) has a greatly adverse effect on the productivity of the machine. 
If relatively large objects or small objects in a number of rows are 
present in mould M.sub.2 then the time for moving plate PA increases, 
because the distance T which has to be travelled is greater, or because 
plate PA has to travel a back and forth distance which is at least equal 
to the width LA of mould M.sub.2 (FIG. 7). 
4. The time for which object or objects O remain n the press, that is with 
their own walls in contact with the cooled wall of cavity of M.sub.2c of 
mould M.sub.2, is another important parameter which affects the 
productivity of a thermoforming machine. In fact as soon as mould M.sub.2 
reaches the position illustrated in FIG. 4, object O is displaced away 
from the wall of cavity M.sub.2c and therefore the stabilising cooling of 
the plastics material which has been subjected to thermoforming ceases. As 
may be seen from the diagram in FIG. 13, the cooling time tst for 
stabilisation in the press is the time between the injection of the 
forming air t.sub.1 (through hole FO) and the start of removal t.sub.3 
(FIG. 4). Normally this time is equivalent to about half the cycle time. 
When it is necessary to increase cooling time tst the rate of the 
thermoforming machine has to be slowed. 
5. Because the objects are directly sent to the stacker from plate PA it is 
not possible to carry out any additional operations (e.g. perforation, 
labelling or the like) on objects O between the removal operation and 
stacking. 
If it is necessary to carry out additional operations on thermoformed and 
stacked objects O, the objects have to be repositioned, and this usually 
means destacking them and sending them to suitable machines to carry out 
the required operations, with a consequent risk of damaging the objects 
and producing rejects. 
One of the greatest disadvantages of thermoforming machines with suction 
plate extraction lies in the shape and restricted dimensions of the 
suction plate itself. In fact, with reference to FIG. 11, it will be noted 
how the pressure difference, between the external environment and the 
negative pressure created by the suction through plate PA in the space 
within thermoformed objects O, creates the force by which objects O are 
attracted to and held against the plate. It can be said to a good 
approximation that this pressure difference is equal to the loss of head 
which air flows Q1/2 and Q2/2 and Q3/2 create when passing through slots 
FE along edges BO. 
Within Plate PA then: 
the air in section S.sub.1 will have a velocity V.sub.1 which will cause a 
flow Q1 to pass, 
in section S.sub.2 it will have a speed V.sub.2 which is different from 
V.sub.1 and such as to pass a flow Q1=Q2. 
in section S.sub.3 the speed will be V.sub.3 which is different from 
V.sub.1 and V.sub.2 and such as to cause the passage of a flow equal to 
Q1+Q2+Q3. Ideal operating conditions arise when Q1=Q2=Q3. As suction plate 
PA has to be inserted between sheet material A and the upper edges BO of 
objects O, its height dimension must be as small as possible so as not to 
constrain the distance by which the press opens and make it excessively 
long. In practice therefore it is preferable to use a configuration in 
which V.sub.3 is very much greater than V.sub.1, so that when it is in 
operation Qt is greater than Q2, which is in turn greater than Q3. This 
means that the system operates under conditions which are very far from 
optimum conditions. 
In thermoforming machines which have double lower female mould of the type 
disclosed in Italian Patent No. 1,053,243 and illustrated diagrammatically 
in FIG. 12, the objects are formed by alternately coupling the two female 
parts M.sub.2s and M.sub.2d with the single upper male part M.sub.1. 
When dies M.sub.1 and M.sub.2 are closed the thermoforming takes place in 
the manner described above in stages 1 and 3. 
With such machines it is possible to obtain advantages in subsequent 
stages, in that: 
1) The distance T travelled by the press on opening its independent of the 
depth or height of the thermoformed objects and may therefore be kept at a 
minimum value sufficient to feed in material A, with a great reduction in 
the passive time in the cycle, as is shown in the diagram in FIG. 13. 
2) The press remains open only for the time necessary to advance sheet 
material A and effect the alternate lateral movement of female moulds 
M.sub.2s and M.sub.2d. These operations take place at the same time, 
without providing any stoppage for removing thermoformed objects O. 
3) The time for which objects O remain in cavity M.sub.2c with their walls 
in contact with the mould is longer than the thermoforming cycle (FIG. 
13), because objects O remain in close contact with the die from the time 
of cutting until the next thermoforming operation in the other female 
mould. In other words the cooling of a thermoformed object O is extended 
throughout the following stages: 
forming, for example in M.sub.1 -M.sub.2s 
cutting out 
press opening 
lateral movement of the double female mould 
closing of dies M.sub.1 -M.sub.2d 
forming in M.sub.1 -M.sub.2d 
The stacking of objects O on these thermoforming machines takes place in 
stacker R.sub.s in the case of the objects formed in M.sub.2s during 
forming stage in mould M.sub.2s and R.sub.d in the case of those formed in 
M.sub.2d. 
Base members M.sub.2fs and M.sub.2fd remove objects O by travelling 
distance C.sub.t (FIG. 12) and stack them alternately pushing the objects 
formed in female mould M.sub.2s into left hand collection or stacking 
device R.sub.s and those formed in female mould M.sub.2d into right hand 
collection or stacking device R.sub.d. Devices R.sub.s and R.sub.d are 
located to the sides of the fixed part of die M.sub.1. It may happen 
therefore that objects O which have recessed angular supporting portions 
(e.g. 2, 3, 4 or more indentations or indented feet located at the same 
level) provided, as is usual in the art, to prevent one object binding 
completely within another during stacking, (which would make it impossible 
for the objects to be then destacked for use), are located in a perfect 
vertical orientation and alignment, because they all come from the same 
mould. In this case it will be seen that there is accurate superimposition 
of two or more consecutive stacked objects, so that the spacing effect of 
the feet or indentations is neutralised and as a result the objects bind 
firmly together making it difficult to separate them. 
Another cause of poor spacing and therefore of irreversible binding between 
the stacked thermoformed objects lies in inaccurate forming of the 
stacking feet or indentations (which generally project towards the 
interior of the object by a fraction of a millimeter or a little more), 
as, being made of a thermoplastics material which is therefore 
dimensionally unstable at the time of forming, these are obtained with 
fairly wide dimensional tolerances. There will therefore be variations in 
the connecting angle to both the feet and the base of each object, 
depending on the nature of the thermoplastics material used, and the shape 
and depth of the objects being thermoformed, which are unacceptable for 
correct stacking of the objects. 
Objects which do not destack, or which destack with difficulty, require 
manual intervention, reduce productivity and almost always end up by 
increasing the number of rejects. 
As will be noted, the distance C.sub.t travelled by base members M.sub.2fs 
and M.sub.2fd depends on the maximum height of the objects O being formed 
and is therefore longer when the objects are deeper. It is essential in 
fact that interference between the bottom of object O and the lateral 
movement and closing of the press is avoided. 
FIG. 12 illustrates pins S.sub.p which centre parts M.sub.2s and M.sub.2d 
with respect to fixed part M.sub.1 as the press closes, through being 
inserted by a certain amount into corresponding seats Z provided in mould 
M.sub.2. A.sub.1 also indicates diagrammatically the members which feed or 
advance sheet material A. 
As in thermoforming machines having a single female mould, so in machines 
having a double female mould, stacking of the objects takes place without 
there being any practical possibility of carrying out additional 
operations on thermoformed objects O, as these are gathered into stacks 
immediately after thermoforming. 
SUMMARY OF THE INVENTION 
An object of this invention is to eliminate or substantially to reduce the 
disadvantages described above which arise with known thermoforming methods 
and machines and forms of extraction. 
Another object of this invention is to provide a method for the extraction 
of thermoformed objects from the forming zone by making use of a suction 
plate which is not subject to critical dimensional constraints. 
A specific object of this invention is to make it possible to carry out a 
whole series of additional and/or auxiliary operations on the thermoformed 
objects during each thermoforming cycle, while keeping the objects outside 
the press in the same mutual positions which they occupied in the forming 
mould. 
Another object of this invention is to provide a substantial reduction in 
the open press waiting time in order to improve productivity and 
efficiency. 
Another object of this invention is to effect a drastic reduction of up to 
one half in the height of the press, with a consequent reduction in the 
masses in movement, the cost of manufacturing the press itself and a 
substantial increase in the speed of movement or lateral movement of the 
press. 
Yet another object of this invention is to provide the production of 
thermoformed objects which may be finished through one or more 
supplementary operations carried out at the same time as a thermoforming 
operation before stacking and packaging, without it being necessary to 
restart processing. 
In accordance with a first aspect of this invention, a method is provided 
for the thermoforming of hollow objects having a base from a sheet of 
thermoplastics material, which effects in one single predetermined working 
cycle: 
the production of a pressed object by hot forming and cutting out of the 
object or objects between one half of a movable double female mould which 
is located in the forming area opposite a male die, 
Movement of the female half of the mould, said half carrying the 
thermoformed object or objects therewithin, towards a corresponding 
discharge area alternately to one side or the other of the forming area, 
removing the object or objects from the female half of the mould in its 
corresponding discharge area and transferring each object to one of a 
plurality of receiving formers of a shape corresponding to the mould, 
which formers can move sequentially in steps along a track, 
sequential movement of the formers towards least one workstation or 
handling station at the same time as the female mould moves back to bring 
its other half opposite the male die in order to produce a subsequent 
formed object, and 
carrying out at least one processing or handling operation on all the 
objects carried by at least one former at the same time as the next formed 
object is produced. 
In accordance with a further aspect of this invention there is provided 
apparatus for the thermoforming of hollow objects incorporating a base 
from a sheet of thermoplastics materials, comprising 
a male die and a double female mould, one half of which mould can move 
alternately with respect to the other half for mating with the male die in 
turn while at the same time carrying the object or objects produced 
previously in the other half of the female mould to an easily accessible 
discharge area, 
a sheet feed to deliver a sheet of thermoforming material in steps between 
the male and female moulds, 
a cutting device which is brought into operation at the end of each closing 
movement of the press, 
a stepwise conveyor having a plurality of plates or formers, each of which 
is capable of receiving and supporting the object or objects from one 
forming operation in the same mutual positions which they occupied in the 
press, 
at least one pick-up head capable of lifting one set of formed objects 
alternately from each half of the double female mould from one side or the 
other of the male die and of transferring them to a corresponding plate or 
former on the conveyor and 
at least one processing or handling station located along the conveyor for 
the simultaneous handling or processing of all the objects from at least 
one forming operation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the figures listed above, it will be noted that the 
thermoforming means or press according to this invention comprises a 
supporting structure 1 on which is mounted a fixed upper plate 2 bearing a 
male die 3, which in the example illustrated is also fixed, a sliding 
die-supporting table 4, which is e.g. supported on roller feet suitable 
for high loads with automatic lubrication (not shown in the drawing) to 
make horizontal movements (arrow A), and a lower plate 5 which can move in 
a vertical direction (arrow B--FIG. 18) which is driven by e.g. two toggle 
units (not shown). Sliding table 4 supports two female moulds (a double 
female mould) 6 and 7 which are identical and are located alongside each 
other at the same level, which are intended to be moved by the sliding 
table 4 alternately beneath the fixed die 3 where they are caused to rise 
up and mate against the die and successively open by being lowered in 
order to be moved laterally with respect to the fixed die 3. In other 
words, mould 6 is moved to the left and mould 7 is moved to the right (as 
seen in the Figs. in the drawing) with respect to the fixed die 3. 
A sheet 8 of thermoplastics material, which may be wound on to a mandrel or 
be derived directly from an extrusion unit combined with the thermoforming 
device, is made to advance by means of a chain feed indicated generally by 
reference numeral 9, in a direction normal to that of the movement of 
double female mould 6, 7 beneath fixed die 3 but above double female mould 
6, 7, in steps, in time with the rate of pressing or forming. 
As will be better seen in FIGS. 18 and 19, fixed die 3 may have a plurality 
of depressions 10 each of which has an open lower end bounded by a free 
edge 11 (FIGS. 21A and 21B) and houses a corresponding male plug 12 fixed 
at the end of a corresponding vertical control rod 13 slidably mounted 
between the upper wall of the fixed die and extending beyond it to meet 
and be joined to an upper activating bar or plate 14, which is in turn 
controlled by activating means, not shown in the drawings, e.g. of a type 
well-known to those skilled in the art. The two female moulds 6 and 7 each 
have a plurality of upwardly open cavities 15 equal in number to the 
number of depressions 10 and having the same spacing, in such a way that 
when a female mould mates with the fixed die each depression or pit 10 
accurately mates with a corresponding cavity 15 below. 
Centering means comprising e.g. four pins 16 borne by upper plate 2, which 
are fixed or which can be caused to project to engage in corresponding 
receiving seats 17 provided in the female mould when the dies are closed 
together are provided for correct mating between female moulds 6 and 7 and 
fixed die 3. 
The base of each cavity 15 is equipped with an extraction device (FIGS. 18, 
19, 21A, 21B and 21C) comprising a head 18 which can move upwards as it is 
controlled by a corresponding rod 19 which is integral with a control bar 
or plate 20, which is intended to release and push out one or more 
thermoformed objects 150 from between the press after the dies have 
opened. 
Advantageously, each cavity 15 may have a constriction 21 forming a step 
around the formed object, the height of which from the base of the cavity 
defines the stacking height H for formed objects 150 (FIG. 21A). 
Lower plate 5 is driven by suitable units (not shown), for example two 
toggle units, in order to effect the vertical closing and opening 
movements between female moulds 6, 7 and fixed die 3. 
Two eccentrics, which by causing plate 5 to move through a small distance 
make it possible to cut out and separate the objects from the sheet, may 
be provided beneath the base of the two toggle units. This operation, as 
is usual in the art, is carried out during the closure of female moulds 6, 
7 against fixed die 3. 
Fixed upper plate 2 has two vertical supporting columns 22 and 23 (FIGS. 
15, 16 and 17), on each of which is rotatably mounted a corresponding 
projecting arm 24, 25 which at its free end bears a suction pick-up head 
26, 27, which is constructed e.g. in the shape of a bell cup which is 
closed off at the base by a perforated suction plate 28 communicating with 
a source of vacuum or negative pressure above in order to draw out the 
air, such as a suction pump, which is not shown, by means of a flexible 
conduit 26a and 27a. As may be better seen in FIG. 20, plate 28 has a 
plurality of through holes 29 placed in an orderly arrangement at a 
distance from the intersection of longitudinal 30 and transverse 31 
suction grooves, advantageously with a spacing equal to that of cavities 
15 in female moulds 6 and 7. 
Arms 24 and 25 are located on one side respectively of fixed die 3 and are 
caused to move angularly about columns 22 and 23 between a position in 
which corresponding pick-up head 26 and 27 is above a corresponding female 
mould 6 or 7, when this is moved laterally completely away from fixed die 
3, and a position outside the thermoforming machine by a corresponding 
motor/reduction gear unit 32, 33 driven in such a way as to cause pick-up 
heads 26, 27 to make rhythmical angular movements in time with the back 
and forth alternating movements of moulds 6 and 7 in order to effect the 
transfer of thermoformed objects 150, as will be further described 
hereinafter. 
Within the radius of action of arms 24 and 25 there is located a stepwise 
conveyor 35 (FIGS. 14, 15, 16, 22 and 23), which is formed of two sliding 
and supporting sides or banks 36, a plurality of plates or formers 37 
slidably supported by the sides and drawn at their two opposite ends by a 
pair of chains 38 which pass round a pair of chainwheels 39 at the ends of 
the conveyor (FIG. 22). Each plate or former 37 has an intermediate pin 40 
providing an articulation to a chain 38 and two lateral rollers or pin 41 
and 42 at each end thereof which engage with the chains. Alongside the 
banks 36 rollers 41 and 42 are free or may run along corresponding 
straight upper 43 and lower 44 guides or rails, while at the transmission 
end of the conveyor, pin 40 is caused to follow a circular path around a 
wheel 39, the front roller (with respect to the direction of movement, 
e.g. roller 41 in FIG. 22) is caused to follow a track which is also 
circular along a corresponding fixed guide 45 which has the same radius of 
curvature as the original curvature of the wheel 39 and the rear roller 
(roller 42 in FIG. 22) is engaged between two radiused teeth 46 of a wheel 
47 which has its own axis of rotation along the line of the wheel 39 and 
the said pitch line. With this arrangement, at the ends of conveyor 35 
each plate or former 37 is returned to a position which is always parallel 
to the other plates or formers and when in the discharge position is 
relatively far from the plate or former which preceded it and the one 
which follows it. 
It is therefore possible to provide a treatment or processing station 50 
(FIGS. 14 and 23) and a stacking station 51 at the transmission ends of 
conveyors 35 and possible intermediate treatment or processing stations as 
will be described below. 
Processing station 50 is designed to perform various operations on formed 
objects 150, which are located in an easily accessible position for 
working units provided at the said station, while in stacking station 51 
the formed objects can be stacked before finally being removed from 
conveyor 35. 
Plates or formers 37 each have a plurality of holes or seats 37a having the 
same diameter (or a slightly smaller diameter) and the same spacings as 
cavities 15 in female moulds 6 and 7, so that they can receive the objects 
obtained from a forming operation transferred thereto by heads 26 and 27. 
Plates or formers 37 are moved stepwise along an upper track along 
conveyor 35, along which they receive formed objects 150 from heads 26 and 
27 alternatively, are stopped sequentially in a stepwise manner at 
processing station 50 and are then passed along a lower track to reach 
stacking station 51. 
Treatment or processing station 50 may be designed to carry out any desired 
additional operation, such as e.g. perforating the bases of shaped objects 
150, dry printing or stamping of the objects, labelling, filling with 
soluble beverage powders, sterilisation, etc. 
In FIGS. 14 and 23, station 50 is illustrated by way of example by a toggle 
driven drilling head equipped with drilling bits 52 arranged with the same 
spacing as holes 37a and formers 37 and operated with the same operating 
rhythm as stepwise conveyor 35. 
However any other suitable operating unit capable of carrying out a desired 
process or manipulation upon the formed objects may be provided instead of 
or in association with toggle-operated driving unit 50. 
Stacking station 51 (FIGS. 14 and 23 to 29) comprises a supporting frame 53 
upon which is located the downstream end of conveyor 35, a lower pusher 54 
which can be driven in an alternating vertical back and forth motion in 
time with the stepwise operation of conveyor 35 and having a plurality of 
pusher heads 55 equal in number to and having the same spacing as holes 
37a in formers 37, and a stacker 56 placed above conveyor 35 in vertical 
alignment with pusher 54. Stacker 56 may be of any suitable type, e.g. 
having a plurality of parallel tubular rods 57 held together by a frame 58 
(FIG. 25) on which is also slidably mounted an upper pusher 59 which can 
also be driven in an alternating back and forth motion as will be 
described below. 
Each rod 57 is advantageously provided with teeth 60 (FIGS. 26 and 28) 
which are retractable in that they are hinged about a transverse axis 61 
so that they can be moved angularly between a position in which they are 
withdrawn into the rod (FIG. 28) so that objects 150 can slide between the 
rods and a position in which they project from the rod (FIG. 26) to engage 
an edge 151 of an object 150. 
As will be better seen from FIGS. 16A, 16B and 25A, it is possible to 
arrange matters in such a way that female mould 6 produces objects 
identical to those produced in female mould 7, but having e.g. four feet 
or indentations 152 offset by a predetermined angle in such a way that 
given that the stacks of objects at station 51 are formed from objects 
deriving from mould 6 and mould 7 alternately, because these are loaded 
onto formers 37 of conveyor 35, the flat part of the base of an object 150 
(even when the bottom edge has a relatively large connecting angle) is 
always brought to rest against a sufficient number of feet 152. 
A similar result is achieved if instead of having a different angular 
orientation of feet 152 in the two female moulds, a different number of 
feet 152 are provided. This naturally makes it possible to have a perfect 
stacking arrangement at all times without any risk of permanent or 
irreversible binding between objects 150 and thus reducing the number of 
rejects. 
Stacker 56 is supported on a trolley structure 62 which can run by means of 
wheels 63 along a beam or section 64 to transfer a plurality of stacks of 
objects 150 from stacker 56, e.g. onto a standing and supporting surface 
65, which may if desired be capable of being raised and lowered, as shown 
diagrammatically in FIGS. 25 and 27. 
Beam 64 may be rotatably supported around its own longitudinal axis 66 and 
may have angular projections around it through a toothed section 67 which 
engages a toothed pinion 68 keyed onto drive shaft 69 of a motor/reduction 
gear unit 70. With this arrangement, stacker 56 can be inclined through 90 
degrees or any intermediate angle thus placing it, for example, in a 
horizontal position and setting it down onto a supporting platform 71 
(FIGS. 29 to 31). Platform 71 is designed to perform a stepwise descending 
movement (through a transmission 72, a screw 73 and a corresponding nut) 
to enable a transverse expeller 74 to transfer a row of stacked objects 
150 to a cage conveyor 75 which carries the stacked objects to e.g. a 
packing station. 
The functioning of the means described above is extremely simple. When the 
press is open a predetermined length of sheet 8 is caused to advance by 
means of chain feed 9 beneath fixed die 3, whereupon female mould 6 or 7 
(e.g. die 6) which is located beneath the fixed die is raised and mated 
against die 3 with the consequent thermoforming of objects 150 and the 
subsequent cutting thereof. Mould 6 together with mould 7 move downwards 
to open the press and immediately afterwards mould-bearing table 4 moves 
laterally so as to carry mould 6 completely away from fixed die 3 and 
mould 7 beneath die 3 ready for the next thermoforming cycle. 
In the meantime pick-up head 26 is moved into the extraction area above 
female mould 6, which is now completely unobstructed, and as soon as mould 
7 closes against the fixed die it removes formed objects 150 from mould 6, 
which had been previously removed or loosened from cells 15 by heads 18 of 
the extraction device. Rotating around its column 22 (FIG. 16) head 26 
moves above a former 37 on conveyor belt 35 and deposits formed objects 
150 into an identical number of holes 37a (FIGS. 15 and 16). 
In the subsequent forming, cycle pick-up head 27 moves over mould 7 which 
has been moved laterally with respect to fixed die 3 into the extraction 
area and, with a similar movement to that of head 26, transfers formed 
objects from mould 7 to former 37 on conveyor 35 in a similar way. In this 
way, head 27 will set objects 150 down on alternate formers on the 
conveyor. The same will be done by pick-up head 26, but on the formers 
left unoccupied by head 27, so that all formers 37 are finally filled with 
objects 150 before they are delivered to processing station 50. 
It will be noted that the fact that each formed object is transferred to 
stepwise conveyor 35 and remains there makes it possible to extend the 
stabilisation times tst outside the press considerably, which is an 
advantageous feature for improving the quality of formed objects 150. In 
fact in the example illustrated objects 150 are supported on the formers 
of conveyor 35 for seven or more thermoforming cycles. 
From time to time it is possible to sample objects 150 from a former 37 
selected at random to check the quality of objects 150 without this 
producing the slightest disturbance in the equipment's operating cycle. 
At workstation 50 the objects are processed or partly filled with powder 
material, or labelled etc., and are then passed along the lower portion of 
conveyor 35 towards stacking station 51, from which they are removed in 
stacks to be delivered for use or to a packing station for delivery. Even 
while they are moving along the lower portion of the conveyor they undergo 
prolonged stabilisation, and remain in the same mutual positions as they 
had in the thermoforming press. 
It will be noted how, in addition to providing easy and uniform control of 
the internal negative pressure over the whole working surface of plate 28, 
the use of suction pick-up heads 26 and 27 is applicable to all 
applications and is not dependent on the existence of an edge 151 on the 
objects being picked up. Also, contrary to the situation in conventional 
systems, through the use of heads 26 and 27 the movement for extracting 
objects 150 from the presses is equal to the stacking height H (FIG. 21A). 
More particularly, with reference to FIG. 21B when a mould 6 or 7 (e.g. 
mould 6) is moved into the extraction or discharge position, head 26 is 
moved into a position above mould 6 at the same time, as already 
mentioned. The distance ho which extraction device 18 and 20 has to move 
for partial extraction of objects 150 before these are picked up by head 
26 is effected while part 7 of the press is carrying out another 
thermoforming cycle. This also applies to the subsequent extraction 
movements performed by head 27, for its rotation and the deposition of 
objects 150 and formers 37 and to its return into position above mould 7 
so that no dead times are added to any of the forming cycles. 
This means that waiting times during which the press is open, which as 
mentioned above with reference to thermoforming machines with a suction 
plate which enters into the pressing or forming area itself represents 30% 
of the thermoforming cycle, are drastically reduced. 
It will also be noted how the removal of objects 150 is only partly 
entrusted to the movement of the heads or bases 18. The objects are in 
fact removed (FIG. 21C) by means of the movement separating the mould and 
the plate, partly caused by lowering of the mould and partly by the 
raising of bases 18. Because these movements take place simultaneously 
with other dead times in each forming cycle they do not affect the 
productivity of the equipment. 
If a comparison is made between the machine according to the known state of 
the art in FIG. 11, it will easily be noted that, if 
ho is the height of objects 150, 
hp is the height of control plate 20, 
ha is the length of the approach travel for stacking, and 
hs is the dimension (height) of a double female mould 6, 7, the total 
height H of a mould M.sub.2s and M.sub.2d in FIG. 12 will be the sum 
Ho=hp+ho+ha+hs. 
The height of female moulds 6 and 7 in FIG. 21B according to this invention 
is instead H=hp+ha+hs, that is H is Ho less than an amount equal to at 
least the maximum height of the thermoformed objects 150. Because the 
height Ho of the mould in a conventional machine with stacking is usually 
slightly greater than twice the height of the thermoformed objects, it can 
be concluded that the extraction performed by heads 26 and 27 in the 
appropriate extraction or discharge areas completely outside the pressing 
area and away from fixed die 3 at least halves the height of female moulds 
6 and 7. 
The reduction in the height of the moulds brings about an appreciable 
decrease in their weight, and therefore their inertia, which means that 
more rapid lateral movements can be performed. 
Also, it will be noted from FIG. 21B that mould 7 is illustrated in the 
extraction or discharge position. The fact that mould 7 is moved in a 
position completely outside the pressing or thermoforming area has made it 
possible to dimension suction heads 26 and 27 in such a way that the sum 
of the flows (Q1+Q2+Q3) all passes through section Hpe. In sections S1, S2 
and S3 the rates of flow will be identical in each and therefore the value 
of the pressure Pi which is set up within the head will be uniform over 
the entire surface of plate 28. This has the result of optimising the most 
important parameter for the satisfactory operation of a pick-up head 26, 
27, with the result that it is possible to achieve the optimum condition 
in which Q1=Q2=Q3. 
The invention described above may be subjected to numerous modifications 
and variations within the scope thereof. Thus, for example, conveyor 35 
may be replaced by a conveyor with an empty return track, or with empty 
formers 37, after being passed around a terminal return wheel of 
considerable diameter or a number of return wheels in such a way that 
stations 50 and 51 can operate on its upper track. Here again processing 
stations 50 may be more than one in number and may be arranged in sequence 
along the conveyor. 
If desired, station 50 may be omitted or in any event may be left inactive 
for particular types of object 150. 
Furthermore,as illustrated in FIGS. 23 and 32, a suction hood 80 for the 
volatile residues produced from thermoplastic material A which is used for 
the thermoforming of objects 150 may advantageously be provided in any 
suitable position above, around or below conveyor 35. A tunnel treatment 
chamber 85, e.g. for sterilization and/or heat conditioning, which may 
surround at least one portion of conveyor 35 and which may be provided 
with a plurality of needles 86 intended for the injection of a fluid, such 
as cold air, to achieve optimum stabilization o objects 150 outside the 
press is also illustrated diagrammatically in FIG. 32. 
If desired, downstream of each pick-up head 26 and 27 a rim curling 
workstation is arranged to form curled rims on all the objects formed in 
the same moulding operation immediately after they have been discharged on 
a plate or former 37. In this case the conveyor 35 has a correspondingly 
greater length by at the least two plates or formers, whereby making it 
possible for the objects to be formed whith a curled rim within the cyclic 
time while being still hot as they have just been picked up from the mould 
6 or 7, and thus there is no need to heat them just for the rim finishing 
operation before reaching the processing station 50. 
Materials and dimensions may be varied in accordance with requirements.