A delivery system for deploying an occlusion device comprises a piston having a threaded proximal end, an elongated delivery catheter having a proximal end, a distal end, and an inner lumen extending between the proximal and distal ends of the delivery catheter, and a drive mechanism comprising an internally threaded nut member and a spring member. The piston is moveable between a first axial position and a second axial position. The internally threaded nut member receives the threaded proximal end of the piston. The spring member, which is coupled to the internally threaded nut member, rotates the nut member to drive the piston from the first axial position toward the nut member to the second axial position. Driving the piston toward the nut member retracts the attached delivery catheter and deploys an occlusion device from within the inner lumen and through the distal end of the delivery catheter.