Abstract: The coffee machine (1) comprises a brewing cylinder (2), a movement system of the brewing cylinder (2) comprising a nut screw (8) engaged with a motorised screw (9), and elastic means (13) compensating the mechanical backlash between the threads of the screw (9) and of the nut screw (8).

Abstract: An infuser unit (1) includes a closing piston (3) and an infusion cylinder (2) which are axially movable selectively or in combination for reciprocal engagement and disengagement to close and open an infusion chamber inside the infusion cylinder (2). An ejection piston (5), engaged in the infusion cylinder (2) and axially movable to expel spent coffee grounds, can also be included. A first radial hydraulic sealing means may be located between the closing piston (3) and the infusion cylinder (2), and a second radial hydraulic sealing means may be located between the infusion cylinder (2) and the ejection piston (5), where at least one of the first and the second hydraulic sealing means has at least one seal (100, 101) having an anti-friction surface coating made of a material free of grease and lubricating oils and compatible with use in contact with foodstuffs and drinking water.

Abstract: The coffee machine (1) comprises a brewing cylinder (2), a movement system of the brewing cylinder (2) comprising a nut screw (8) engaged with a motorised screw (9), and elastic means (13) compensating the mechanical backlash between the threads of the screw (9) and of the nut screw (8).

Abstract: An infuser unit (1) for a coffee machine, comprising a closing piston (3) and an infusion cylinder (2) which are axially movable selectively or in combination for reciprocal engagement and disengagement so as to close and open an infusion chamber inside the infusion cylinder (2), in which a dose of coffee can be positioned, an ejection piston (5) engaged in the infusion cylinder (2) and axially movable in the infusion cylinder (2) so as to expel the spent coffee grounds, a first radial hydraulic sealing means between said closing piston (3) and said infusion cylinder (2), and a second radial hydraulic sealing means between said infusion cylinder (2) and said ejection piston (5), at least one between the first hydraulic sealing means and the second hydraulic sealing means comprising at least one seal (100, 101) having an anti-friction surface coating made of a material free of grease and lubricating oils and compatible with use in contact with foodstuffs and drinking water.