Patent ID: 7487713

Claim:
A mechanically and hydrodynamically operated brewing unit for automatic beverage vending machines, said brewing unit comprising: a rotatable base provided with a compartment adapted to act as a brewing chamber, said compartment being open on top and comprising a bottom wall; means to let water under pressure into said compartment; connecting means for conveying brew to a beverage dispensing point; and a brewing head movable relative to the rotatable base by means of a crank-connecting rod mechanism, said brewing head comprising: a hollow containment structure; a first hollow piston housed within said hollow containment structure movably relative thereto, wherein a first interstice is provided between the first piston and the hollow containment structure; a second piston housed within said first piston movably relative thereto, wherein a second interstice is provided between the first piston and the second piston; and elastic means opposing the movement of said second piston, wherein the first interstice and the second interstice are both hydraulically connected to a fluid supply means provided for operating said first and second pistons by the direct action of a fluid under pressure.