Note: Descriptions are shown in the official language in which they were submitted.
20~085
A COFFEE MACHINE
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to coffee-making
machines for professional use, these machines being
intended to produce at each utilization a quantity of
brewed coffee corresponding to a small cup. klore
specifically, the invention is concerned with machines
of the type comprising a plurality of brewing
receptacles carried by a rotary support so designed as
to bring each receptacle in succession opposite to a
particular workstation forming part of a series of
workstations which have different functions and which
are located at intervals on the same circular path.
Description of the Prior Art
Patent No. CH 387,252 describes a machine of
this type in which provision is made for three different
workstations in sequence following an initial coffee
powder filling station, namely a second station for
compacting the powder, a third station for pouring hot
water in order to brew the coffee and a fourth station
for washing prior to a return to the initial station.
Thus, in this machine, there exists an intermediate
station for compacting coffee powder between the
initial coffee powder filling station and the brewing
station. In consequence, at any moment, a receptaale
filled with coffee powder is located in a stationary
position opposite to the compacting station while an
infusion of coffee takes place in the preceding
receptacle. This has a detrimental effect on the
quality of the beverage thus obtained since it is not
made with freshly ground powder but with powder which
has remained stationary over a certain period of time
at the location of the intermediate station if the
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machine is not in continuous use.
Moreover, a machine of this type has a
disadvantage in that the brewing receptacles become
rapidly clogged. In fact, the washing opera$ion
carried out in the course of a normal coffee production
cycle cannot be sufficiently efficient to remove all
the particles of coffee powder attached to the walls
of the brewing receptacles, particularly as it is
impossible to introduce detergent products in these
receptacles. In the event of clogging of a machine of
this type, it is consequently necessary to resort to
the services of a specialized repairman, which is
liable to put the machine out of service over a
considerable period of time, with all the disadvantages
which may result in the case of a coffeeshop or other
public drinking establishment.
Furthermore, the machines of the type
considered which are in current use have particularly
complex mechanisms, thus increasing their capital cost
as weIl as the potential danger of failures. This is
the case in particular with the machine disclosed in
patent No. CH 387,252. In this machine, the brewing
receptacles are located at intervals at the periphery
of a plate which is subjected to a series of different
movements during each period of use, namely a downward
axial movement, a movement of partial rotation and an
axial movement of upward return. Thi~ aaaordingly
requires the presence of a particularly aomplex
mechanism with the disadvantages which result in
regard to both capital expenditure and reliability.
Accordingly, the object of the present
invention is to provide a coffee-making machine which
is so designed as to remove all these disadvantages.
SUMMA~Y OF THE INVENTION
The distinctive feature of the coffee machine
2060085
in accordance with the invention lies in the fact that
the machine is provided with two series of workstations
dedicated to two different operating cycles, placed on
one and the same circular path, and comprising :
a) For a normal operating cycle, the following stations
in succession :
- an initial coffee powder filling station,
- a second and diametrically opposite station at
which compacting of the powder followed by pouring
of the predetermined dose of hot water for brewing
the coffee are performed immediately after initial
filling, the device for controlling the
displacements of the rotary support of the brewing
receptacles being capable of moving each receptacle
directly from the initial station to the brewing
station without any intermediate 8top,
- a third station for removal of coffee grounds
without stopping the~rotary support of the brewing
receptacles and during the same movement of
rotation of said support.
b) For a specia~l cleaning cycle, the following stations
in succession : ~
- a station for depositing a detergent product and
located between the first two stations of the
25 ~ normal~cycle,
a station for pouring hot water for the
cleaning operation proper, this station being
constituted by the second station of the normal
cycle.
By virtue of the design thus proposed, the
receptacle which has received a dose of freshly ground
coffee powder moves immèdiately to the brewing station
at which preliminary compacting of the powder also
takes place. Under these àonditions, coffee~is always
brewed with fresh}y ground powder, thus makin~ it
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possible to obtain coffee of better quality than in
machines of the same type in the prior art. Moreover,
any danger of clogging is eliminated owing to the
existence of a special cleaning cycle which is separate
and distinct from the normal cycle of production of
coffee drinks and which permits highly efficient
cleaning. It should be added that the mechanisms of
the present coffee machine are particularly simple
since the rotary support of the brewing receptacles
carries out solely a partial movement of rotation each
time the machine is put into operation, both in the
case of the special cleaning cycle and in the case of
the normal cycle of production of coffee drinks.
In accordance with another distinctive
feature of the present coffee machine, the control
device of this machine automatically initiates the
cleaning cycle at each complete stoppage of operation
of the machine. In addition, this cycle can be
initiated by the user at any moment which he or she
may choose.
In accordance with yet another distinctive
feature, each brewing receptacle is fitted with a
removable bottom filter and provision is made in the
special cleaning cycle for an additional workstation
located after the hot water pouring station. Said
additional station is so arranged as to permit with-
drawal of the removable parts provided in each brewing
receptacle inaluding the bottom filter so that they may
be thoroughly cleaned by hand whenever necessary. The
result thereby achieved is that any danger of clogging
of the coffee machine is radiaally eliminated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of a coffee
machine in accordance with the invention, this view
being taken along a vertical plane which passes through
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the line I-I of FIG. 2.
FIG. 2 is a diagram illustrating the position,
in the same horizontal plane, of the different
workstations provided in this machine.
FIG. 3 is a partial sectional view taken
along a vertical plane which passes through the line
III-III of FIG. 2.
FIG. 4 is a diagram illustrating the
operations performed at the different workstations in
a normal cycle of production of coffee drinks.
FIG. 5 is a similar view corresponding to the
special cleaning cycle.
FIG. 6 is a sectional half-view to a larger
scale showing an alternative form of construction of
the compacting piston.
DETAILED DESCRIPTION OF THE INVENTION
The machine which is illustrated in the
drawings has only two coffee-brewing receptacles la
and lb placed in diametrically opposite positions on a
common support 2 which~can have the shape of a simple
bar forming a connection between these two reaeptacles.
Preferably, the assembly is constituted by a single-
~; piece component of molded metal alloy and can be driven
in rotation by a vertical shaft 3 located at the center.
Said assembly is removably mounted on said shaft by
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means of a wing nut 4 or any other suitable fastening
element which can readily be detached.
The bottom portion of each receptacle la or lb
contains a piston 5 which is pierced with a plurality
of holes and provided with a removable filter grid 6.
Said piston is carried by a rod 7 which is mounted for
free sliding motion within a bore 8 formed in the lower
end of the corresponding receptacle. In its normal
position, the piston 5 rests on the bottom wall of said
receptacle and is thus located above an infusion-liquid
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discharge nozzle 9. In this position, the rod 7 of the
filter piston projects beneath the corresponding
receptacle and the lower end of said rod bears on a
circular track 10, the function of which will be
explained below.
~ he rotary shaft 3 is driven by an electric
motor 12 via a series of gears contained in a
protective casing 11. The motor is of a special type
known as a n stepping" motor and operated in dependence
on a control unit designed to deliver pulses which are
necessary in order to determine angular displace~ents
of precise amplitude for the rotary support 2 of the
two receptacles la and lb. This accordingly makes it
possible to bring each receptacle successively to the
location of a particular workstation forming part of a
series of stations having different functions.
Thus the changes of position of the brewing
receptacles are obtained with precision without making
use of end-of-travel stops or like systems which have
the disadvantage of being subject to disturbances of
adjustment. This technology therefore makes it
possible to obtain excellent reliability of the coffee
; machine under consideration.
The machine in accordance with the invention
is distinguished by the fact that it has two separate
and distinct workstations dedicated to two different
operating cyales, namely a normal operating cycle for
the preparation of coffee drinks and a second cycle
which is a special cleaning cycle. However, the
dif~ferent workstations of these two series are located
at angular intervals on the same circular path 13, the
center O of which coincides with the center of the
~; shaft 3, at least one of these stations being common
to both operating cycles if so required. In addition
~ 35 to these two operating cycles, provision is also made
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for a rinsing cycle which utilizes the workstations of
the normal operating cycle and which will be described
below.
The normal operating cycle comprises the
following three workstations in succession :
- an initial station A for filling with coffee powder,
provision being made above this station for a feed
nozzle 14 connected to the outlet of a coffee-grinding
unit 15, start-up of said unit for the purpose of
grinding a predetermined dose of coffee being
initiated by putting the present coffee machine into
operation,
- a second station B which is diametrically opposite
and in which infusion of aoffee powder takes place in
order to deliver a predetermined quantity of beverage
into a small coffee-cup 16 via a pouring spout 17,
; - and a third station C for removal of coffee grounds,
this station being located between the stations B
and A.
Furthermore, FIG. 2 shows the respective
angular positions of these three stations.~ As will be
apparent, the support 2 of the filtering receptacles
is driven in rotation in the direction of the arrow F.
It is worthy of note that the control unit
of the~motor~l2 is intended each time to impart one
half-revolution to the support 2 in order to transfer
each brewing receptacle directly from the filling
station A to the brewing station B. The other
receptacle obviously moves from station ~ to station
;~ 30 without stopping opposite to station C for removal of
coffee grounds. This is in any case essential in order
to ensure that the receptacle which has just received
coffee powder at station A should pass directly to the
brewing station B.
It must also be pointed out that station B
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is designed to carry out both preliminary compacting
of the coffee powder and then pouring of the intended
dose of hot water for brewing. The powder-compacting
operation is performed by a pressure piston 18 provided
with a detachable grid 19. The rod 20 of said piston
is slidably mounted within a guide-block 21 and is
displaced in sliding motion by means of a pinion 22
disposed in mesh with a screw-and-nut system 23. Said
pinion is in turn driven by an electric direct-current
motor 24. This fact being taken into consideration, it
is possible to determine the torque developed by said
motor by simply measuring the intensity of the current
which flows through the motor. In consequence, this
makes it possible to determine the conditions in
which the ground coffee is compacted. Furthermore,
it is thus possible to store in memory the value of
current intensity to be adopted for any subsequent
compaction of the coffee powder. Irrespective of the
quantity of coffee placed within the corresponding
brewing receptacle, it is therefore always possible
to ensure that the powder is compacted in exactly the
same manner.
Immediately after compaction of the coffee
powder, a predetermined dose of hot water is poured
from a pipe 25 into the brewing receptacle located
opposite to station B, the outlet of said pipe being
located above said station. The means for supplying
the pipe with hot water do not need to be described
since they are of conventional design in coffee
machines of this type.
By virtue of the fact that each brewing
receptacle passes immediately from station A to station
B, coffee is brewed from freshly ground coffee powder.
This accordingly makes it possible to produce a
beverage of much better quality than in machines of
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this type which are currently in use.
As already mentioned, the station C for
removal of coffee grounds M is a station at which each
receptacle la and lb only passes without stopping. At
S the location which corresponds to this station, the
circular track lO already mentioned has a raised
portion lOc with connecting ramps lOa and lOb on each
side. Thus, when a receptacle la or lb has left
station B, the lower end of the rod 7 of the
corresponding filter piston 5 is caused to slide along
the ascending ramp lOb so as to reach the raised
portion lOc. In consequence, this has the effect of
lifting the piston 5 above the corresponding receptacle
as shown in the right-hand portion of FIG. 4. At the
location of station C, provision is made for a fixed
scraper 26 which is intended to cause removal of the
coffee grounds M which are present on the top face of
the piston 5 by virtue of the very fact that the
corresponding receptacle la or lb is passing at that
moment beneath said scraper. However, by means of the
descending ramp lOa, the piston 5 then returns to its
initial position before the receptacle again reaches
the filling station A. :
In regard to the special cleaning cycle,
this cycle comprises~successively, in addition to the
initial station A which is common to the normal
operating cycle :
- a station D for depositing a detergent product from
a feed pipe 27, this station being located between
the first two stations A and B of the normal cycle,
~:- a second station at which hot water is poured for
::the cleaning operation proper, this station being
constituted by the second station B of the normal
cycle,
- a third station E providing the possibility of
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disassembly of the detachable parts provided within
each brewing receptacle, this station being located
after the hot water pouring station B.
The control unit of the present machine is
programmed so as to ensure that there does not take
place any discharge of coffee powder at the location
of the initial station A while the special cleaning
cycle is taking place and that the pressure piston 18
does not come into action at the location of station B.
It will be apparent that this unit is also programmed
so as to impart in such a case angular displacements
which are different from those carried out during the
normal operating cycle in order to ensure that each
receptacle should be caused to stop successively
opposite to the different stations A, B, D and E.
In regard to the last-mentioned station E,
a point worthy of note is that this station is placed
above the raised portion lOc of the circular track 10.
At this location, the piston 5 is thus thrust upwards
above the corresponding receptacle l as shown in the
right-hand portion of FIG. 5. It is therefore an
extremely easy:matter to grip this portion~together
with its filter grid 6 by hand in order to withdraw the
assembly from the corresponding receptacle 1. This
permits thorough cleaning of these two stations outside
the machine and consequently to ensure a wholly
efficient cleaning operation since the grid 6 aan then
be separated from the piston 5. Similarly, the grid 19
which i8 fitted on the pressure piston 18 aan also be
detached for subsequent cleaning outside the machine.
The piston 18 also can be readily cleaned when a
receptacle la or lb is located opposite to the
disassembly station E. In this instance, no brewing
receptacle is present at station B since the receptacles
are located in diametrically opposite positions. In
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this situation, it is a very easy matter to gain access
to the piston 18 for thorough cleaning.
The existence of a special cleaning cycle
permits wholly efficient cleaning of the filtering
receptacles and the different parts with which they are
equipped. This accordingly makes it possible to avoid
the risks of clogging which exist in prior-art machines
of the same type and consequently their attendant
drawbacks. Furthermore, the cleaning operation per-
formed is made even more efficient by the possibilityof disassembly at the location of station E, of the
detachable parts with which each brewing receptacle is
equipped. It should be added that, if the need arises,
the assembly formed by the two receptacles la and lb
can even be completely disassembled for subsequent
cleaning outside the machine. To this end, it is only
necessary to unscrew the nut 4 which serves to fix this
assembly in a removable manner.
The control unit of the coffee machine under
consideration is so designed that the special cleaning
~- cycle is initiated automatically each time the machine
is completely stopped, for example at the end of a day
or at closing time of a coffeeshop or other public
drinking establishment equipped with this machine.
However, the control unit also enables the user himself
(herself) to initiate this cleaning cycle at any moment
which he or she may choose, for example if he or she
` considers that there is a potential danger of clogging
of the filters and brewing receptacles.
The rinsing cycle provided in addition to the
; normal operating cycle and cleaning cycle utilizes the
stations of the first of these two cycles. However,
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when this rinsing~cycle is being performed, the control
unit of the machine suppresses the operation which
consists in pouring coffee powder at the location of
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the initial station A as well as the powder-compacting
operation at station B. Consequently the only operation
which takes place is the pouring of hot water at the
location of station B, thus carrying out the intended
rinsing operation.
Moreover, the control unit of the machine is
made dependent on a system designed to control the time
of filling of a coffee cup. The arrangement is such
that, when this time interval exceeds a predetermined
value corresponding to the normal time of flow of water
through the coffee powder, this control system produces
action on the control device in such a manner that this
device then initiates the rinsing cycle. Thus as soon
as the residue of spent coffee powder begins to
stagnate and causes an increase in the time of flow of
water through the coffee powder, this automatically
initiates a rinsing cycle, thereby preventing any risk
of clogging. However, the control unit also permits
initiation of the rinsing cycle by hand at any moment
which the user may choose.
It should be recalled that the mechanism
provided in this coffee machine is relatively simple
since it is only necessary to impart predetermined
angular displacements to the rotary support 2 of the
two brewing receptacles. These displacements can in
fact be controlled with precision by making use of the
stepping motor 12. The control unit of the maahine
therefore comprises a microprocessor in order to
deliver the necessary pulses to said motor. The
assembly also includes a sequenaer and a power supply.
The use of a control unit comprising a
microprocessor makes it possible to store a large
number of parameters in said microprocessor in order to
control a number of elements of the machine. Thus the
control unit will be able to control the coffee-grinding
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unit lS by causing it to operate during a predetermined
period of time in order to obtain the desired quantity
of ground coffee.
Moreover, as has already been mentioned, this
control unit is designed to initiate both the cleaning
cycle and the rinsing cycle under the conditions
described earlier.
As will be readily apparent, the coffee
machine in accordance with the invention is not limited
to the example of construction described in the
foregoing. Thus in this example, provision is made for
only two brewing receptacles located in diametrically
opposite positions on their rotary support 2, in which
case the two stations A and B of the normal cycle are
lS also located in diametrically opposite positions in
order to permit direct transfer of each receptacle from
station A to station B. However, the rotary support 2
could carry a greater number of brewing receptacles.
It would accordingly be necessary to provide suitable
angular positions of the two stations A and 8 in order
to ensure that there always takes place a direct
transfer of each reoéptacle from the initial station A
to the brewing station B without any intèrmediate stop.
During the normal operating cycle, there would in such
a case be intermediate stops on the return path from
station B to station A but these intermediate stops
would not correspond to workstations.
By reason of its advantages, the aoffee
machine in aacordance with the invention is more
partlcularly intended to be employed in public drinking
;~ establishments, coffeeshops, cafeterias or the like for
supplying cups of cofee to consumers.
In accordance with an alternative embodiment,
the coffee machine thus described embodies an improve-
ment which makes lt possible to control compaction of
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the coffee powder with greater efficiency.
To this end, the piston 18 is fitted with a
seal around its entire periphery in order to obtain
good fluid-tightness between the piston 18 and the
internal walls of the receptacles la or lb. This
arrangement is sub]ect to a disadvantage in that the
seal is in rubbing contact with the receptacle walls
and that this friction adds an additional force to be
overcome by the motor 24. Since this force is not
constant, compaction of the coffee powder is not
constant either.
An expedient devised with a view to
circumventing this disadvantage and illustrated in
FIG. 6 consists in providing a hollow seal which is
inflated by the hot water used for brewing.
Reference being made to this figure, it is
apparent that the pipe 25 is no longer a fixed pipe
which opens freely above the piston 18 but has a
flexible portion 25a tightly fitted over a tube 25b
which is forcibly inserted in a bore 18a of the piston
18.
The bottom end of said bore 18 communicates
via a duct 28 on the one hand with a radial duct 29
which opens into a channel 30 and on the other hand
with a plurality of ducts 31 through which the hot
water will flow into the coffee powder contained in
the receptacle 1.
The channel 30 is a circular channel formed
in the piston 18 around itC entire periphery. There is
placed within said channel a seal 32 which is hollow and
which communicates with the duct 29 via an orifice 33.
The result thereby achieved is that the water
which arrives through the flexible pipe 25a will fill
the duct 29 and, by passing through the orifice 33,
will cause inflation of the seal 32.
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It is thus possible to determine the diameter
of the piston 18 and of its seal 32 so as to ensure
that, when the seal is in the deflated state, the
piston 18 can penetrate into the receptacle with play.
When the piston 18 has pressed the coffee until the
desired compaction couple is attained, the pump
discharges hot water which inflates the seal 32, thus
achieving fluid-tightness between the piston and the
receptacle throughout the duration of the brewing
process. When brewing has been completed, the pump
stops, the brewing chamber is decompressed, the seal
32 is deflated and the piston 18 can return up~ards
without any friction.
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