Device for pressing a dose of ground coffee powder
A device ( 2 ) for pressing a dose of ground coffee powder includes a filter holder cup ( 3 ) having a filter ( 4 ) for depositing the dose of ground coffee powder, an attaching support ( 7 ) in which the cup ( 3 ) is separably attached, a grinder ( 8 ) for coffee beans including a slide ( 9 ) for dispensing ground coffee having an outlet ( 10 ) positioned above the mouth ( 5 ) of the cup ( 3 ), a pressing piston ( 15 ) for pressing the dose of ground coffee powder present in the filter ( 4 ) mounted in the cup ( 3 ), and a lifting mechanism for lifting the pressing piston ( 15 ) in a position above the outlet ( 10 ) of the slide ( 9 ).
1. A device ( 2 ) for the preparation of a dose of ground coffee powder comprising:
a filter holder cup ( 3 ) having a filter ( 4 ) for the introduction and collection of said dose of ground coffee powder,
a pressing piston ( 15 ) of said dose of ground coffee powder configured for presence at a position within said filter holder cup ( 3 ) and at a position above said filter holder cup ( 3 ), and
a lifting mechanism of said pressing piston ( 15 ), configured to vertically translate the pressing piston ( 15 ) between the position within said filter holder cup ( 3 ) and the position above said filter holder cup ( 3 ); wherein the lifting mechanism includes:
a control element ( 19 ) rotatable about a horizontal axis, the control element ( 19 ) comprising an elastic clutch; and
a transmission configured to transform rotation of the control element ( 19 ) about the horizontal axis into vertical translation of the pressing piston ( 15 ), wherein the elastic clutch connects the control element ( 19 ) to the transmission; wherein the transmission comprises:
a vertical rack ( 20 ) solidly constrained to the pressing piston ( 15 ); and
an arch of a cogwheel ( 21 ) supported by the horizontal axis connected to said control element ( 19 ) and engaging the vertical rack ( 20 );
wherein the lifting mechanism is configured, during rotation of the control element ( 19 ) and up until the pressing piston ( 15 ) is resting on an upper surface of said dose of ground coffee powder present in said filter holder cup ( 3 ), so that the control element ( 19 ) and the arch of the cogwheel ( 21 ) rotate in a joint manner; and is configured, beginning from where the pressing piston ( 15 ), while being lowered, compacts said dose of ground coffee powder present in said filter holder cup ( 3 ), so that further rotation of the control element ( 19 ) no longer results in further lowering of the pressing piston ( 15 ), due to resistance provided by compacted ground coffee powder, and so that further rotation of the control element ( 19 ) deforms the elastic clutch, which transfers a pressing force to the pressing piston ( 15 ), said pressing force gradually increasing proportionally to the deformation of the elastic clutch.
2. The device ( 2 ) according to claim 1 , wherein said lifting mechanism reversibly activates said pressing piston ( 15 ) between a pressing position, wherein said pressing piston ( 15 ) is internal to said filter holder cup ( 3 ), and said position above said outlet ( 10 ) of said slide ( 9 ).
3. The device ( 2 ) according to claim 1 , further comprising a guide ( 16 ) for the vertical translation of said pressing piston ( 15 ).
4. The device ( 2 ) according to claim 1 , wherein said pressing piston ( 15 ) is rigidly supported by a vertical stem ( 18 ) which extends above said pressing piston ( 15 ).
5. The device ( 2 ) according to claim 1 , wherein said pressing piston ( 15 ) and said filter ( 4 ) exhibit a circular conjugated shape.
6. The device ( 2 ) according to claim 1 , wherein said elastic clutch comprises a torsion spring ( 23 ).
7. The device ( 2 ) according to claim 1 , wherein said control element ( 19 ) is a manual lever or a knob.
8. The device ( 2 ) according to claim 1 , wherein an indicator ( 29 ) of a pressing force is provided which identifies a current configuration of said elastic clutch.
9. The device ( 2 ) according to claim 1 , wherein selection of the dose of ground coffee powder is independent of a selection of the pressing force.
10. A coffee machine ( 1 ) having the device ( 2 ) according to claim 1 .
11. The coffee machine ( 1 ) according to claim 10 , further comprising a modular construction composed of structurally independent modules, one of which being formed by said device ( 2 ).
12. The device ( 2 ) according to claim 1 , wherein the control element ( 19 ) has a hollow body ( 24 ) within which a bearing ( 25 ) is fastened, where said bearing ( 25 ) is coupled rotatingly with a coaxial bearing sleeve ( 26 ), axially having, in turn, a seat ( 27 ) for fastening to an axis stem.
13. The device ( 2 ) according to claim 12 , wherein the elastic clutch is a helical torsion spring ( 23 ), interposed along the horizontal axis between the bearing ( 25 ) and the coaxial bearing sleeve ( 26 ), the torsion spring ( 23 ) having one end ( 23 a ) fastened to the bearing ( 25 ) and one end ( 23 b ) fastened to the bearing sleeve ( 25 ).