Apparatus for the manufacture of ground coffee-powder bags

A device for supplying and metering freshly ground coffee powder in an apparatus for packaging bags of coffee powder in an apparatus for manufacturing bags of ground coffee-powder for packaging of bags of coffee powder comprising a device for supplying and metering freshly ground powder including a metering device, a distribution disc and a closing disc provided with through-holes which can be aligned in predetermined angular positions of the discs themselves, so as to supply one or more measures of coffee powder at a time into cavities formed in a link conveyor supporting a bottom strip of filter paper shaped so to have successive receiving cavities. The through-holes in the metering device and in the closing disc are two in number so as to make use of the fact that in general circles of the metering device and closing disc intersect each other always at two separate points.

BACKGROUND OF THE INVENTION 
FIELD OF THE INVENTION 
The present invention relates to so-called coffee-bag making machines, 
namely machines intended for the manufacture of bags containing coffee 
powder. 
DESCRIPTION OF THE PRIOR ART 
It is well known that in recent years a technology for the preparation of 
espresso coffee and coffee infusions has been developed, being based on 
the use of so-called bags or tablets comprising a measured and 
precompressed quantity of freshly ground coffee powder and a filter paper 
wrapping. These bags are preserved in wrappings which are impervious not 
only to water but also, and in particular, to the oxygen in the air, which 
is the main factor responsible for ageing and organoleptic deterioration 
of the coffee powder, being the impervious wrapping preferably filled with 
nitrogen or some other inert gas. 
Apart from the preservation methods, an important problem is that of the 
industrial production of these bags or tablets, since numerically large 
quantities (of the order of tens of thousands per day must obviously be 
produced. Preferably the industrial production involves the manufacture of 
fairly long strips of bags which are joined together alone one edge where 
a weakening line is formed, for example by means of micro perforation, so 
as to be able to separate by means of tearing a single bag from the strip 
at the time of use. 
Obviously it is also possible for the strips of bags to be divided up so 
that the individual bags may be kept detached from one another. 
A machine useful for such a manufacturing method is for example that 
described and illustrated in British Patent No. 1,011,872, said machine 
comprising substantially a translating surface on which there is placed a 
strip of filter paper (bottom strip) having, at regular intervals, 
cavities of a shape and size suitable for receiving a predetermined 
measure of freshly ground coffee powder. 
The measure of coffee powder deposited in the cavities is then compressed 
and a top covering strip, also consisting of filter paper, is then placed 
over the said strip, after which the two overlapping strips are bonded 
together along the entire periphery of each measure or tablet of fresh 
coffee powder, for example by means of heat-sealing. More specifically, 
the bottom strip of filter paper cooperates with a chain of plates movable 
along the support surface and forming a closed ring, each plate being 
provided with an upper surface having formed in it cavities with the same 
shape as the cavity which is to be provided in the strip of filter paper 
prior to depositing therein the required measured quantity of freshly 
ground coffee powder. 
The strip of paper is unwound from a supply reel and covers the 
aforementioned upper surface of the plates, after which each plate passes 
through a plurality of stations inside which suitable operating components 
perform the sequence of operations briefly described above. 
Therefore, after the station where the bottom strip of filter paper is 
deposited, there is located in succession: 
a station for forming the cavity in the bottom strip of filter paper; 
a station for supplying a measure of coffee powder; 
a station for pressing the measure of coffee powder already present in the 
cavity, so that the upper surface of the plate located underneath the 
bottom strip of filter paper acts as a support or counter-surface; 
a station for unwinding and depositing a top covering strip of filter 
paper; 
a station for heat-sealing the two strips of filter paper along the entire 
perimeter of the compressed coffee powder. 
Moreover, suction means operate along the path of the plates, said means 
having substantially the function of retaining the bottom strip of filter 
paper and removing any coffee powder which during deposition and/or 
pressing escapes from the edges of the tablet. 
Obviously, the aforementioned stations must be operated in synchronism, 
which poses significant problems not only as regards the mechanical 
structure of the machine, but also in terms of the maintenance 
requirements and frequency of repair, to the detriment, therefore, of the 
productivity. 
The European Patent No. 0,225,494 describes an apparatus for packaging the 
said bags or tablets, which comprises a fixed support surface on which a 
plurality of flat cup-shaped devices intermittently advances, each of said 
devices being formed by a substantially quadrangular plate having a 
central recess with rounded edges, the bottom of said recess being in 
communication, via a plurality of holes, with openings formed in the 
aforementioned support surface, said openings in turn communicating with a 
vacuum source, the apparatus comprising two operating stations, the first 
of which forms a corresponding cavity in the bottom strip of paper 
deposited on the aforementioned recess, fills it with a measure of coffee 
powder supplied by a suitable metering device and compacts and presses 
said powder, while in the second station heat-sealing of the top strip of 
paper onto the bottom strip containing the pressed measure of coffee 
powder is performed. 
This apparatus is characterized in particular by the fact that the cavity 
formed in the bottom strip of paper is kept in the desired shape owing to 
the vacuum applied underneath the strip itself through the holes formed in 
the bottom of the cavity to which the aforementioned bottom strip of 
filter paper is made to adhere during forming. 
Another feature which characterizes this apparatus consists in the 
configuration of the device for metering and supplying the predetermined 
measure of coffee powder into the preformed cavity of the bottom strip of 
paper, for which reference should be made to the detailed description and 
the drawings. 
As already mentioned, these types of apparatus must have a very high 
production rate, so that any improvement which increases this productivity 
and/or simplifies the machine from a structural point of view and/or 
reduces the probability of faults or malfunctions is of great importance 
from an industrial point of view. 
SUMMARY OF THE INVENTION 
It has now been discovered--this constituting the subject of the present 
invention--that it is possible to improve the apparatus with regard to 
metering of the ground coffee powder, an improvement which concerns both 
the number of bags which may be manufactured for each production cycle of 
the apparatus and the mechanical components of the metering device. 
The principle of the present invention is based essentially on the fact 
that each straight line or circle intersecting a circle meets it at two 
separate points and this principle therefore allows the metering and 
simultaneous delivery of at least two measures of coffee powder. 
The present invention therefore relates to an apparatus for the manufacture 
of bags of ground coffee powder, of the type described and illustrated in 
European Patent No. 0,225,494, characterized in that it comprises: 
one or more fixed metering containers having a bottom provided with a pair 
of through-holes of diameter corresponding to the volumetric quantity of 
coffee powder to be supplied onto the bottom strip or strips of paper so 
as to form one or more measures for a bag; 
a first distribution disc, rotating intermittently and provided with a 
plurality of pairs of holes spaced angularly so that for each angular 
rotating movement a pair of holes is arranged in vertical alignment with 
the pair of holes in the bottom of said metering containers; 
one or more intermittently rotating discs, each provided with a pair of 
through-holes spaced so that in one of the positions assumed by the disc 
during its intermittent rotation said pair of holes is aligned with one of 
said pairs of holes in said distribution disc; 
a fixed plate having one or more pairs of holes in vertical alignment with 
the pair of holes in said closing discs when said latter pair is aligned 
with a pair of holes in said distribution disc and drive means consisting 
of a single motor operating a single drive shaft which operates said 
distribution disc; 
gearing means for transmitting in a synchronized manner the movement from 
said distribution disc to said closing disc, said drive shaft having 
rigidly connected to it a mechanical intermittent device for controlling 
the intermittent angular movements of the corresponding distribution disc, 
a second intermittent device being rigidly connected to the feed chain 
having cavities for receiving individual doses of ground coffee powder so 
that, for each advancing movement of the chain, two of said cavities are 
arranged in a position suitable for receiving simultaneously individual 
doses of coffee powder. 
It should be remembered also that, if a disc is rotated, the stresses for 
causing rotation of this disc are reduced by an amount corresponding to 
the reduction in the angle of rotation of the latter. Consequently, if the 
number of pairs of holes on the distribution disc is increased, the latter 
is forced to rotate covering smaller angles and hence reducing the 
stresses on the said disc. 
For example, with four pairs of holes, the distribution disc must rotate 
covering angles of 90.degree., with eight pairs it rotates through 
45.degree., with 12 pairs it rotates through 30.degree., etc., so that it 
is convenient to increase the number of pairs of holes. 
Finally, it is possible to multiply further the speed of an apparatus 
according to the present invention, arranging several fixed metering 
containers above the first distribution disc and several closing discs, 
alternately with the metering containers, provided that the number of 
metering containers is equal to the number of stopping discs. This fact 
causes a reduction in the speed of rotation of the metering disc and, at 
the same time, increases the production speed.

In the description which follows, where possible, use will be made of the 
same reference numbers as those in the European Patent referred to. 
Therefore, the apparatus, to which the present invention relates, comprises 
a conveying chain 10, the links of which are formed by cup-shaped devices 
12. The conveying chain is moved by a drive roller 14 in the direction of 
the arrow 16 and forms a closed loop around a transmission roller 18. The 
operating path of the chain 10 extends over a support surface 22. The 
conveying frame 10 has mounted above it a frame 24 with two shoulders 26 
and 28 which rotatably support a cam shaft 30 operated by a reducer 
gearing 32 and carrying a plurality of cams 34, 36, 38 and 40 which are 
synchronized with one another in relation to operation of the different 
members and devices which are controlled by the said cams. 
The reference number 42 denotes a reel of strip-type filter paper 48 
intended to form the bottom supporting strip of the series of bags or 
tablets generally denoted by the reference number 50 at the exit end of 
the apparatus. Each bag or tablet 50 consists of said bottom strip 48, a 
top closing strip of filter paper 52 and a compressed measure of fresh 
coffee powder 54 accommodated in the cavity formed between the two strips. 
The strip of filter paper 52 is taken from a reel 56 and guided so as to be 
deposited on top of the bottom strip 48 and the compressed measures of 
coffee powder 54 already arranged on the bottom strip. 
The cross-member 62 of the frame 24 has mounted on it in the following 
order: 
a unitary die 64 having the functions indicated below; and 
a forming and heat-sealing member 140 having the function of shaping the 
top strip of filter paper 52 on the bottom strip 48 and on the compressed 
measures of coffee powder 54 present thereon. 
Returning to the unitary die 64, its purpose is to preshape and fill with a 
measured amount of coffee powder the bottom strip of filter paper 52 and 
for this purpose it has a base plate or sole 66 for ensuring adherence of 
the bottom strip 48 to the preformed cavity in each cup-shaped device 12, 
so that the paper is correspondingly shaped and kept in this configuration 
by the suction action applied via the through-holes 13 which are connected 
to a vacuum source (via the ducts 148, the compartment 152 and the duct 
158). 
The supply of the measured amount of coffee powder 72 inside the cavity 
formed in the bottom strip 48 of filter paper is performed via the hole 
70, in the manner explained below, followed by operation of the ram or 
press-piece 74 which has its bottom operative end shaped in the manner of 
an upturned cup, matching the shape of the cavity formed in the filter 
paper 48. During supplying of the measured amount of coffee powder 72 and 
the subsequent pressing operation the action of the vacuum is eliminated, 
whereas this action is resumed when the cup-shaped device passes into the 
position located immediately downstream, but still underneath the die 64, 
opposite an immediately overlying concavity 65, so as to remove (and if 
necessary recycle) any coffee powder which could prevent mating with the 
top strip of filter paper and subsequent heat-sealing. 
At last, after the top strip 52 has been deposited, the heat-sealing device 
140 performs mutual heat-sealing of the matching filter-paper edges of the 
two strips 48 and 52 all around the compressed measure of coffee powder. 
With reference now to FIGS. 2, 3 and 4, a detailed illustration is provided 
of the device for supplying and metering the freshly ground coffee powder 
which cooperates with the hole 70 of the die 64 and which, forming the 
specific subject of the present invention, replaces that specifically 
provided in the apparatus described and claimed in European Patent No. 
0,225,494. 
This supplying and metering device comprises a storage and metering 
container which is generally denoted by the reference number 200 and fixed 
to a part of the immobile frame of the apparatus, such as for example to a 
bracket 212 rigidly connected to the cross-member 62. The container 200 
has a generally cylindrical shape and freshly ground coffee powder is 
supplied into it, for example from a milling unit (not shown), the 
distribution of said coffee powder over the entire bottom surface being 
ensured by a blade-type leveller 202, extending radially from a hub 204. 
The bottom 210 of the cylinder 200 has two holes 206 (A and B) which are 
spaced angularly at a predetermined angle and have cooperating with them 
respective expulsion press-pieces 208 (A and B) which can be operated 
between a raised position and a pressing and expulsion position via known 
means (not shown). It is worth noting that the thickness of the bottom 210 
of the metering cylinder 200 is predetermined so that the cylindrical 
volume defined by each of the through-holes 206 (A and B) corresponds to 
the volume occupied by each predetermined measure of ground coffee powder. 
The bottom 210 of the cylinder 200 has mounted underneath it the actual 
distribution and metering unit comprising an upper rotating disc 214 
having formed in it a plurality of pairs of through-holes 216 (A and B), 
the centres of which are arranged on a concentric circumference with 
respect to the disc 214; the angular distance between the through-holes 
216A and 216B of each pair is exactly the same as that existing between 
the holes 206 (A and B), with their diameters also being the same, so that 
rotation of the disc 214, the centre of which is conveniently offset with 
respect to that of the metering cylinder 200, brings in succession the 
pairs of holes 216 (A and B) into vertical alignment with the pair of 
holes (A and B) in the bottom of the cylinder 200. 
The disc 214 has a peripheral crown 218 meshing with a pinion 220 mounted 
rotatably on a second pinion 236 by means of a pin 222; the mechanical 
group consisting of the two pinions 220 and 236, the respective bearings 
238 and 240 and the pin 222 provided with a head 242 is in turn rotatably 
mounted between the bracket 212 and a fixed distribution plate 224. 
The disc 214 has mounted underneath it a second rotatable closing disc 226, 
useful for opening and closing off communication between the pairs of 
holes 216 (A and B) of the disc 214 and additional through-holes 228 (A 
and B) formed in the fixed distribution plate 224 and more precisely in a 
cylindrical seat 230 formed in the thickness of the fixed plate 224. 
The second rotating disc 226 has formed in it a pair of holes 232 (A and B) 
with a diameter and spacing which is the same as that of the pair of holes 
216 (A and B) in the first rotating disc 214, so that during rotation of 
the two discs the holes 216 (A and B) are located in vertical alignment 
with the holes 232 (A and B). The rotating disc 226 is also made to rotate 
by means of meshing between the peripheral crown 234 on the disc itself 
and the aforementioned pinion 236. From FIGS. 2 and 4 it can be readily 
seen that the the pinion 236 is also housed in a corresponding seat formed 
in the thickness of the fixed plate 224, in a position so as to allow the 
aforementioned meshing. 
A shaft 244 is provided for the rotational operation of the distribution 
disc 214, said shaft passing through the hole 246 formed in the fixed 
plate and terminating at the top through the hole 248 formed in the bottom 
2 10 of the cylinder 200 so as to operate the hub 204. Obviously the shaft 
244 also passes through a hole 250 formed in the disc 214 so that the disc 
itself is rigidly keyed onto the shaft 244. The through-holes 228 (A and 
B) formed in the seat 230 of the fixed plate 224 are aligned with the 
translation path of the link chain 12, in such a way that the 
aforementioned holes are aligned vertically with the cavities 250 (A and 
B) formed in the bottom strip of filter paper 48 following the action of 
the base plate or sole 66. Finally it must be pointed out that the shaft 
244 is operated by a single electric motor (not shown) with an 
intermittent movement provided by a four-stage intermittent device; so 
that the distribution disc 214 is able to fill two holes 216 (A and B) 
each time it stops. 
This is made possible by the fact that said filling operation is performed 
when these two holes are closed by the bottom plate of the fixed plate 
224. The subsequent rotation, through 90 degrees, of the disc 214 brings 
the two filled holes still closed by the bottom part of the fixed disc 
into an intermediate position and subsequently further rotation of the 
same disc 214 brings the same two holes into the position for discharging 
into the cavities 250. 
In this case, however, said discharging operation is not performed 
simultaneously for both holes, but first at the one situated further 
downstream with respect to the direction of forward movement of the chain 
10 and then at the one situated further upstream. In this connection it 
should be pointed out that, precisely for this purpose, the closing disc 
226, via transmission of the movement effected by means of the two 
gearings 220 and 236, performs a double rotation compared to the disc 214, 
so that one of the two openings 216A or 216B, depending on the 
circumstances, remains closed, while discharging of the other one into the 
corresponding cavity 250 is performed. 
Moreover, the movement of the chain 10 is also controlled by a three-stage 
intermittent device, so as to cause forward movement of the chain itself 
by two cavities 250 between one stop and another. 
From the above description it seems obvious that, with the present 
invention, the considerable advantages mentioned above are achieved, both 
as regards the increase in productivity of the apparatus and as regards 
structural simplification, from a mechanical point of view, of the device 
for supplying the measured quantity of freshly ground coffee powder. 
It is understood that conceptually and mechanically equivalent variations 
and modifications are possible and foreseeable without departing from the 
scope of the present invention and that therefore these modifications may 
be contemplated within the scope of the invention itself 
For example, although the upper rotating disc 214 of the embodiment 
illustrated in FIGS. 2, 3 and 4 has four pairs of holes 216, nevertheless 
it is not limited to this number, it being possible to use in general 4n 
pairs of holes, where n is a whole number variable from 1 to a higher 
number, allowing, within the limits of constructional convenience, the 
presence of a number of pairs of holes 216, which is a multiple of four. 
Furthermore, the cups 12 to be filled on the chain 10 do not have to be 
necessarily adjacent to one another, but could be separated by a certain 
number of empty cups 12 to be filled during subsequent movements of the 
chain 10. 
Moreover, nor is one limited to having a single metering container 200 and 
a single stopping disc 226 diametrically opposite to the metering 
container, but one could have for example two diametrically opposite 
metering containers which are alternately arranged between two stopping 
discs also diametrically opposite and arranged along a line perpendicular 
to that joining the two metering containers. 
Obviously, with a metering disc of suitable dimensions, the number of 
metering containers may also be greater than two, as may be the number of 
stopping discs, the only condition to be satisfied being that the number 
of metering containers must be equal to the number of stopping discs. 
It is pointed out for the sake of greater clarity that the chains 10 
carrying the cups 12 form, with their axes, chords which intersect the 
circle of the distribution disc at two points, this being substantially 
the principle on which this invention is based.