Why are the blades not moving while hedge trimmer motor is on?

Mine (black and Decker) was the same, you have broken the clutch mechanism!
Take the bottom off the unit (4 screws) and take the blade unit off, here you will see a gear which drives the blades back and forwards, with a offset pin, I drilled thro the two pieces, slightly c/sink both sides and put a small shear pin thro, then hammer the two sides together and the file excess away, replace and all should be well, if it shears too quickly increase the pin size, but not too big, it needs to shear if you hit something hard.

davey
June 2005