Device for automatically interrupting the supply of electric power to a motor and its utilization

Device for automatically interrupting the supply of electric power to a motor (4) when this latter is locked under the action of a mechanical resistance, comprising means (5) coupled for rotation with the motor (4) and displaceable under the action of the centrifugal force generated at the time of this rotation in order to put the electric power supply of the motor in circuit and in order to put this power supply out of circuit when said centrifugal force drops, characterized in that it comprises a body of revolution (2) fixed on one of the ends of the shaft (3) of the motor (4) and provided with recesses (7) for said masses (5), a disk (12) which is free with respect to this shaft and rests against that face (2a) of the body (2) in which the entrances (7b) of the recesses (7) of said masses (5) are formed and masks said entrances (7b) and a cap (13) covering said disk (12) and attached to the body (2), which is provided on the face remote from the body of revolution (2) with a central protuberance (14) whose apex is in contact with a conductive strip (10) of the switch (6), said central protuberance (14) of the disk (12) being capable of fitting within a complementary opening (15) formed in the end-wall (13b) of the cap (13).