Abstract: The invention discloses an arrangement specially designed for the releasable coupling of a tool shank and a motor assembly of the type used in hand-held blenders. The motor assembly has a cylindrical nozzle that projects from the distal base thereof, inside which the output shaft of the motor is housed, on the outer side of which it has a threaded formation to quickly screw it onto the tool shank. The coupling arrangement has a secure means of retention of the tool shank in the position in which it is coupled to the motor assembly, this means consisting of a click-in piece that secures the distal base of the motor assembly and substantially projects from the plane of said base, together with the formation of multiple partitions formed inside the bell on the coupling end of the tool shank, these partitions extending radially and angularly equally-spaced to define cavities designed to receive and retain the click-in piece during the coupling operation of the tool shank and the motor assembly.