both the motor driven blades module 14 and the base 16 are seen to have two cylindrical necks 26 and 27 respectively that bear external threads 28 and 29 these threads are located at some distance from the ends of the necks as shown in fig2 the neck 26 is formed with a raised tab 30 to mate with a notch 31 in the top flange 19 of the shaft this is done as a means of locating the blades module with respect to the base which also has this type of tab feature finally it should be noted that the module neck 26 does not oscillate but supports a bearing 33 on which the rest of the module may oscillate an electric cord 36 extends from the motor 13 down through the module neck 26 and shaft 15 and is terminated at its bottom end with a male connector 38 another electric cord 40 that is formed with a plug 41 at one end extends into the base 16 to a female connector 43 to which the connector 38 may be conventionally connected whereas the connector 38 is flexible it being at the end of cord 36 that extends freely through the.