Expanding and contracting yo-yo

Abstract

The expanding and contracting yo-yo is a spool formed by a pair of disks connected by a narrow diameter pin having a string wound around the pin. At least one, and preferably both, of the disks has a plurality of overlapping wings (also referred to as air foils or leaves) pivotally attached to the periphery of the outer face of the disk. The wings are capable of expanding outward to unfold like the petals of a flower and contracting to form a dome on the outer face, similar to a closed flower bud. The yo-yo has a flexible, resilient loop attached to the inner face of the wings to bias the wings to the closed dome configuration. When the yo-yo is dropped and pulled back in, centrifugal force, centripetal force, alternate lift and drag of air flow, and resilient bias cause the wings to alternately pivot and unfold outward, followed by pivoting inward to reform the dome shape.

1 . An expanding and contracting yo-yo, comprising:
 at least two disks, each of the disks having a periphery, an outer face and an axial center;   a dowel connecting the axial centers of the disks to form a spool;   a string attached to and wound around the dowel pin, the string having an end formed into a finger loop;   a plurality of overlapping wings pivotally attached to the periphery of at least one of the disks, the wings unfolding to an expanded position extending from the periphery of the disk and folding to a contracted position against the outer face of the disk; and   a flexible, resilient member attached to the wings, the resilient member resiliently biasing the wings to the contracted position.   
   
   
       2 . The expanding and contracting yo-yo according to  claim 1 , wherein said wings define a dome when in the contracted position. 
   
   
       3 . The expanding and contracting yo-yo according to  claim 1 , wherein each of said wings has a pivot pin extending therefrom and said at least one disk has a plurality of hinge tubes disposed about its periphery, each of the pivot pins being rotatable in a respective one of the hinge tubes. 
   
   
       4 . The expanding and contracting yo-yo according to  claim 1 , wherein said at least two disks consists of two disks. 
   
   
       5 . The expanding and contracting yo-yo according to  claim 4 , wherein said wings are pivotally attached to both of said two disks. 
   
   
       6 . The expanding and contracting yo-yo according to  claim 1 , wherein said wings comprise adjacent pairs of wings having different colors. 
   
   
       7 . The expanding and contracting yo-yo according to  claim 1 , wherein said flexible, resilient member comprises a loop. 
   
   
       8 . The expanding and contracting yo-yo according to  claim 1 , wherein said flexible, resilient member comprises an elastic band. 
   
   
       9 . An expanding and contracting yo-yo, comprising:
 at least two disks, each of the disks having a periphery, an outer face and an axial center;   a dowel connecting the axial centers of the disks to form a spool;   a string attached to and wound around the dowel pin, the string having an end formed into a finger loop;   a plurality of overlapping wings pivotally attached to the periphery of one of the disks, the wings unfolding to an expanded position extending from the periphery of the disk and folding to a contracted position against the outer face of the disk; and   means for resiliently biasing the wings to the contracted position.   
   
   
       10 . The expanding and contracting yo-yo according to  claim 9 , wherein said wings define a dome when in the contracted position. 
   
   
       11 . The expanding and contracting yo-yo according to  claim 9 , wherein each of said wings has a pivot pin extending therefrom and said at least one disk has a plurality of hinge tubes disposed about its periphery, each of the pivot pins being rotatable in a respective one of the hinge tubes. 
   
   
       12 . The expanding and contracting yo-yo according to  claim 11 , wherein said at least two disks consists of two disks. 
   
   
       13 . The expanding and contracting yo-yo according to  claim 12 , wherein said wings are pivotally attached to both of said two disks. 
   
   
       14 . The expanding and contracting yo-yo according to  claim 9 , wherein said wings comprise adjacent pairs of wings having different colors. 
   
   
       15 . The expanding and contracting yo-yo according to  claim 9 , wherein means for resiliently biasing comprises a loop, the loop being attached to each of said wings. 
   
   
       16 . The expanding and contracting yo-yo according to  claim 1 , wherein means for resiliently biasing member comprises an elastic band, the elastic band being attached to each of said wings. 
   
   
       17 . An expanding and contracting dome, comprising:
 at least one disk having a periphery, an outer face and an axial center;   a plurality of overlapping wings pivotally attached to the periphery of the at least one disk, the wings unfolding to an expanded position extending from the periphery of the disk and folding to a contracted position against the outer face of the disk;   a flexible, resilient member attached to the wings, the resilient member resiliently biasing the wings to the contracted position; and   wherein when the disk is spun the resilient bias provided by flexible, resilient member is overcome by centrifugal force to thereby open the pivotally attached wings, and as the spinning disk slows down the resilient bias provided by flexible, resilient member overcomes the centrifugal force to thereby close the pivotally attached wings.