Coffee grinder with weight control device of the dose of ground coffee

A coffee grinder with a weight control device of a dose of ground coffee, comprising:

• an electric motor (3);
• a grinder group (4) driven by said electric motor (3) and housed inside a grinding chamber (5);
• a feed hopper (6) for feeding coffee beans to be ground to said grinding chamber (5);
• a delivery channel (7) for delivering the ground coffee to a support fork (8) of a filter-holder to be loaded with the ground coffee;
• and
• a load cell (16) mechanically connected to said support fork (8) and a microprocessor (17), which controls an operation of the electric motor (3) to determine a desired final dose having a final value (Pf) of the ground coffee inside said filter-holder,
• wherein said microprocessor (17) contains control firmware which, when weighing a new dose of coffee as required by a user, activates a weighing program which provides the following operational steps in succession:
• a) activating the electric motor (3) to cause the grinder group to grind the coffee beans;
• b) continuously controlling, with said load cell (16), a detected weight (Pr) of the ground coffee which, through said delivery channel (7), reaches the filter-holder leaning on said support fork (8);
• and
• c) determining a shutdown of the electric motor (3) when said detected weight (Pr) reaches a value Pr=Pf−Δ where Δ is a predetermined value corresponding to a weight of the ground coffee reaching the filter-holder during a shutdown transient of the electric motor (3),
• wherein said Δ value is initially predetermined experimentally, depending on constant characteristics of each individual type of coffee grinder, and is continuously calibrated during operation of the coffee grinder, depending on variable conditions in which said coffee grinder is operating, and
• wherein the control firmware of said microprocessor (17) further provides a continuous calibration program of said Δ value which comprises:
• d) storing a predetermined number (n) of subsequent weighings;
• e) calculating a mean weigh value on said predetermined number (n) of subsequent weighings;
• f) determining a mean deviation between said mean weigh value and the final value (Pf) of desired weighing;
• and
• g) modifying the Δ value directly proportional to said mean deviation.