"Filter holder for a coffee machine of the ""espresso"" type"

A filter holder designed for use with a coffee machine of the "espresso" type comprises a receptacle for receiving a perforated filter cup. The filter cup and the receptacle together define an infusion collecting chamber underlying the filter cup. The infusion collecting chamber communicates via an outlet with a distributing funnel extending downardly from the receptacle. At the opening of the outlet channel there is disposed the free end of a flexible blade extending transversely of the channel. The free end of the flexible blade is applied with a predetermined force against the opening of the channel such that the infusion discharged from the outlet channel emanates in a laminar flow and is atomized upon contact with a partition surrounding the free end of the blade, to produce a substantial quantity of foam.

The invention relates to a filter holder adapted to be mounted on a coffee 
machine of the "espresso" type and comprising a receptacle for receiving a 
filter in the form of a cup that is intended to contain an amount of 
ground coffee and whose bottom is perforated, and an infusion collecting 
chamber situated beneath the said filter and comprising an outlet channel 
for the infusion whose opening communicates with a distributing funnel 
that permits the infusion to flow out from the said receptacle. 
In "espresso" machines now in existence, hot water is conducted onto the 
ground coffee contained in the filter at a pressure from 10 to 15 bar. In 
passing through the coffee, the water pressure decreases to atmospheric 
upon its arrival at the outlet of the filter. The foam which thus appears 
on the coffee is due principally to the generation, in the infusion 
exiting the filter, of air bubbles which were compressed in the water 
circuit of the machine and in the ground coffee. Consequently, this foam 
is produced in only a slight quantity. 
The invention especially has as an object to improve the production of 
foam. 
According to a primary characteristic, the filter holder is equipped with a 
device for making foam, comprising a flexible blade disposed transversely 
at the opening of the channel, one end of which is anchored on a base 
integrated with the bottom wall of the chamber, and the other end of which 
is free. The blade is applied with a predetermined force against the 
opening so as to produce a laminar jet of the infusion only when the 
pressure in the chamber is greater than the force with which the free end 
of the blade is applied against the opening. The filter holder also 
comprises a partition arranged around the blade and extending downwardly 
such that the jet of infusion becomes atomized on the partition to form 
the foam. 
Thanks to this device for making foam, there is produced by a venturi 
effect, at the level of the blade and by fractionation against the wall, 
an air-infusion mixture sufficiently great to create a thick foam in the 
dispensed coffee. 
The invention also has as an object to produce an enriched foam using a 
foodstuff such as chocolate. 
According to another embodiment of the invention, the bottom of the 
receptacle is formed with a hole to constitute the outlet channel for the 
infusion and the flexible blade is secured directly to the external 
surface of the bottom of the receptacle, whereas the partition is 
constituted by the internal peripheral surface of the funnel thus 
providing a housing for a foodstuff, the said funnel being to this end 
removably mounted on the external surface of the bottom of the receptacle 
by means of a removable fixation device. 
Thanks to this embodiment, the infusion jet also strikes the piece of 
chocolate or chocolate powder contained in the housing. Thus, the 
chocolate progressively melts and creates a much more plentiful foam, 
rendering the coffee foamier and with a very agreeable taste.

The filter holder shown in FIGS. 1 and 2 is intended to be mounted on a 
coffee machine of the "espresso" type and comprises, in a manner known in 
itself, a receptacle 1 for receiving a filter 2 in the form of a cup which 
is intended to contain an amount of ground coffee and whose bottom 3 is 
perforated, and an infusion collecting chamber 4 situated beneath the 
bottom 3 and comprising an outlet channel 5 for the infusion, the opening 
6 of which communicates with a distributing funnel 7 extending downwardly 
from the bottom 8, 8' of the receptacle and permitting the collected 
infusion to flow out from the receptacle into a coffee cup generally 
placed below. 
According to a first embodiment (FIG. 1), the filter holder has in the 
bottom 8 of the receptacle a central conduit forming a distributing funnel 
7 and is equipped with a plate 9 formed from plastic material which has a 
hole formed at its center to form the outlet channel 5 and which is 
arranged between the bottom 3 of the filter 2 and the internal surface 10 
of the base 8 of the receptacle 1, the said plate 9 constituting the 
bottom wall of the infusion collecting chamber 4. 
The perforated bottom 3 of the filter 2 rests via its periphery 11 on an 
annular sealing element 12, such as a silicone gasket, which is disposed 
on the upper surface 13 of the plate 9 and whose thickness thus defines 
the height of the said chamber. 
The filter holder is equipped with a device for making foam comprising a 
flexible blade 14 disposed beneath the bottom wall transversely of the 
opening 6 of the channel 5, one end 16 of which is secured to a base 17 
integrated with the lower surface 15 of the bottom wall of the chamber 4 
and the other end 18 of which, being free, is applied with a predetermined 
force against the opening 6, as well as a partition 19 arranged around the 
blade 14 and extending downwardly. 
Thus, when the pressure of the liquid in the chamber 4 exceeds the force 
with which the free end 18 is applied against the opening 6, there is 
produced at that time a laminar jet of infusion which becomes atomized on 
the partition 19, preferably situated close to the blade, thus forming the 
foam which then flows into the funnel 7. It will be appreciated that this 
foam is more or less substantial as a function of not only the distance at 
which the partition 19 is implanted with respect to the opening 6, but 
also the application force which permits the laminar jet to entrain more 
or less air captured laterally by a venturi effect, at least in the 
longitudinal direction of the blade 14. 
FIG. 2 illustrates a second embodiment of the invention in which, for ease 
of understanding, the elements similar to those of FIG. 1 are given the 
same reference numerals. As shown, the receptacle 1 contains a filter 2 
which rests on an annular gasket 12 disposed directly on the internal 
surface 10' of the bottom 8' of the receptacle 1. The bottom 8' of the 
receptacle 1 constitutes the bottom wall of the chamber 4 and is formed 
with a hole so as to constitute the outlet channel 5 for the infusion, and 
the flexible blade 14 is anchored on a base 17 integrated with the lower 
surface 15' of the said bottom 8', whereas the partition 19 is constituted 
by the internal peripheral surface of the funnel 7 thus providing a 
housing 21 for a foodstuff 22 such as powdered chocolate or pieces of 
chocolate, the said funnel being for this purpose removably mounted on the 
lower surface 15' of the bottom 8' by means of a removable fixation device 
of the bayonet type shown at 23. 
It will be appreciated that the operator, after removing the funnel 7 from 
the receptacle 1, places for example a piece of chocolate 22 in the 
housing 21. Then, he secures the funnel 7 onto the receptacle 1 by means 
of the bayonet closure 23. As soon as the free end 18 of the blade 14 lets 
escape a laminar infusion jet from the opening 6, this latter strikes not 
only the wall 19 but also the pieces of chocolate, causing their 
progressive melting and an infusion-chocolate emulsion which permits 
producing a plentiful foam and a coffee having a very agreeable taste.