Patent ID: 7503400

Claim:
A device for driving an attachment element into a work piece comprising: a first drive element for driving a plunger in a first direction away from an attachment element to be driven, and said plunger storing energy in an energy storage mechanism when moved in said first direction; a second drive element to drive said plunger in a second direction opposed to said first direction, and release stored energy stored in said energy storage mechanism in combination with a power force from said second drive element to said plunger when moved in said second direction to drive an attachment element; said first and second drive elements for moving said plunger in said first direction and in said second direction being the same drive element, said same drive element being an electric coil; and a position sensor for sensing a position of said plunger, a control receiving a signal from said position sensor when said plunger reaches a rearwardly spaced position, and driving said plunger in said second direction once said position sensor has identified said plunger as being in said rearwardly spaced position.