the mounting base 23 to the drive 40 in a bayonet type fastening action using a 45 degree twist this action is similar to attaching a cap to a glass jar the drive member 25 shown in fig1 and 2 is inserted into the receptacle rod 26 simultaneously with the attachment of the mounting base 23 to drive housing 40 referring to fig4 a spring loaded lock clip 46 keys and locks the drive member 25 to the receptacle rod 26 when the lock clip engages pre aligned slots 48 present in the drive member 25 and the receptacle rod 26 the disengagement of the mounting base 23 from the drive 40 is effected simultaneously with disengagement of the drive member 25 from the receptacle rod 26 when both are rotated counterclockwise by drive member 25 pushing lock clip 46 out of its slot 47 as illustrated in fig4 eliminating the keying between drive member 25 and receptacle rod 26 this action is similar to the removal of a cap from a jar by twisting counterclockwise and lifting while only one form of engagement of canister 10 to drive 40 was described in the preferred embodiment of this invention it would be clear to those skilled in the art that other similar methods for quick fastening of these parts can be utilized effectively the above described method of engagement has however an important feature that should be noted since the receptacle rod 26 may be at its lower position at the time when the drive member 25 is.