Coffee brewing machine

  • US 5,237,911 A
  • Filed: 10/28/1992
  • Issued: 08/24/1993
  • Est. Priority Date: 12/03/1991
  • Status: Expired due to Fees
First Claim
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1. A coffee brewing machine, particularly an espresso coffee brewing machine, comprising:

  • a container for fresh cold water;

    a boiler means for heating said fresh cold water;

    a brewing chamber adapted to receive coffee powder;

    a pump means for feeding said fresh cold water from said container to said boiler means and therefrom into said brewing chamber;

    a piston fitting into said brewing chamber and being movably mounted such that it can be moved into said brewing chamber to compress said coffee powder contained in said brewing chamber and removed from said brewing chamber;

    drive means for driving said piston into said brewing chamber and for retracting it out of said brewing chamber;

    said drive means comprising an electric DC motor adapted to be connected to a DC power supply having a nominal output voltage lower than the mains voltage;

    an electric resistor connected in series with said electric DC motor for the adaptation of the higher mains voltage to the operating voltage of said electric DC motor;

    first rectifier means and means for connecting said first rectifier means in series with said electric resistor and said electric DC motor for operating said motor in a first sense of rotation;

    second rectifier means and means for connecting said second rectifier means in series with said electric resistor and said electric DC motor for operating said motor in a second, opposite sense of rotation;

    a hotplate for heating cups and for keeping the brewed coffee warm;

    said electric resistor connected in series with said electric DC motor serving as a heating element for said hotplate.

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