Turn pink lever (having an eccentrical pin) to raise or lower left end of the orange shaft thus to connect or disconnect the clutch.
Teeth on the worm and on the wheel must be rounded to ease the engagement process.
Positioning device for the lever is not shown. The clutch connection should be done when the driving shaft stops

Instead of bevel gear drive, double Cardan joint can be used for transmitting motion to the worm.
This idea is taken from US patent 20110247440 A1.