Patent ID: 7461967

Claim:
Releasable coupling device between a tool shank and a motor assembly in hand-held blenders, in particular a coupling device that enables the user to perform a firm and reliable connection between the two components and easily separate the tool shank ( 2 ) from the motor assembly ( 1 ) of the blender when cleaning, maintenance or replacement operations of the tool shank ( 2 ) are to be performed, the connection between which is determined by an externally threaded cylindrical nozzle ( 3 ) formed on the closing base at the distal end of the motor assembly ( 1 ), through which the drive shaft is accessed, and a nut portion ( 10 ) complementarily threaded on its inner face, formed on the inside of a coupling bell piece ( 4 ) on the proximal end of the tool shank ( 2 ), the inside of the coupling bell also having multiple angularly equally-spaced partitions ( 11 ) that extend radially between said nut portion ( 10 ) and the inner surface of the wall of the coupling bell ( 4 ) to form a succession of hollow interior segments, which is characterised in that the motor assembly ( 1 ) additionally includes an external formation ( 7 ) that projects from the closing base of its distal end, adjacent to and radially separated from the nozzle ( 3 ) of the motor assembly ( 1 ), said formation ( 7 ) having a cylindrical hole in which a spring ( 9 ) is housed, which outwardly pushes on a retaining ball ( 8 ) that partially projects through the mouth of said external formation ( 7 ), and in that the bell ( 4 ) includes, on one of the radial partitions ( 11 ), a cup-shaped formation ( 12 ) with the edge of the partition into which it is integrated, said cup-shaped formation being generally semispherical with its mouth slightly raised in relation to the edge of said partition ( 11 ) to which it is connected, said cup-shaped formation being designed and provided with suitable dimensions to house the retaining ball ( 8 ) when, with the relative rotation between the tool shank ( 2 ) and the motor assembly ( 1 ) during the mutual coupling operation between the two pieces, said cup-shaped formation ( 12 ) reaches the position of the ball ( 8 ), pushing it first against the action of the spring and then allowing it to be housed therein.