Isolating decoupler

Abstract

An isolator decoupler comprising a shaft ( 1 ), a pulley ( 2 ) journalled to the shaft, a torsion spring ( 10 ) engaged between the pulley and a carrier ( 9 ), the torsion spring loaded in an unwinding direction, a wrap spring ( 11 ) engaged between the carrier and the shaft, the wrap spring comprising a cylindrical inner portion ( 94 ) and a planar outer portion ( 93 ) connected by a tapered portion ( 155 ), and the inner portion frictionally engaged with the shaft in a winding direction.

We claim: 
     
         1 . A method of forming a spring wire comprising:
 cutting a spring wire having a cross-sectional dimension of 1.5 mm×2.5 mm to a predetermined length;   loading multiple spring wires into a fixture wherein the spring wires are parallel and resting on the 1.5 mm side;   gang grinding the spring wires to obtain a portion having taper from 2.5 mm to 1.2 mm;   removing the spring wires from the fixture and placing them on a magnetic table so the spring wires are parallel and rest on the 1.2 mm side;   gang grinding the spring wires to obtain a second portion having a taper from 1.5 mm to 0.6 mm; and   winding each spring wire into a final shape.   
     
     
         2 . The method as in  claim 1 , wherein:
 winding each spring wire to comprise an inner portion and an outer portion connected by a tangential portion;   configuring the inner portion to be cylindrical;   configuring the outer portion to be coplanar; and   the coplanar portion being normally disposed to an axis A-A of the inner portion.   
     
     
         3 . A method of forming a spring wire comprising:
 cutting a spring wire having a rectangular cross-section to a predetermined length, the rectangular cross-section having a long side and a short side;   loading multiple spring wires into a fixture wherein the spring wires are parallel and resting on the short side;   gang grinding the spring wires to obtain a portion having taper of the long side dimension to approximately 50% of the long side dimension;   removing the spring wires from the fixture and placing them on a magnetic table so the spring wires are parallel and rest on the long side;   gang grinding the short side of the spring wires to obtain a second portion having a taper to approximately 50% of the short side dimension, the short side tapered portion coextensive with the long side tapered portion; and   winding each spring wire into a final shape.