Yoyo with propeller blades

Abstract

In an example embodiment, a yoyo includes an axle, a first body and a second body coupled to the axle, and a string windable about the axle within a gap between the first body and the second body. The first body may include an outer rim and multiple propeller blades that extend inward from the outer rim toward the axle.

What is claimed is: 
     
         1 . A yoyo, comprising:
 an axle;   a first body and a second body coupled to the axle; and   a string windable about the axle within a gap between the first body and the second body;   wherein the first body comprises:
 an outer rim; and 
 multiple propeller blades that extend inward from the outer rim toward the axle. 
   
     
     
         2 . The yoyo of  claim 1 , wherein the multiple propeller blades impart a thrust on the yoyo in a direction parallel to an axis of rotation defined by the axle when the first and second bodies rotate about an axis defined by the axle. 
     
     
         3 . The yoyo of  claim 1 , wherein the second body comprises:
 a second outer rim; and   multiple second propeller blades that extend inward from the second outer rim toward the axle.   
     
     
         4 . The yoyo of  claim 3 , wherein a pitch direction of the multiple second propeller blades of the second body is the same as a pitch direction of the multiple propeller blades of the first body. 
     
     
         5 . The yoyo of  claim 3 , wherein a pitch direction of the multiple second propeller blades of the second body is opposite from a pitch direction of the multiple propeller blades of the first body. 
     
     
         6 . The yoyo of  claim 1 , wherein the axle and the first and second bodies have an aggregate mass, each of the first and second bodies has a diameter, and a ratio of the aggregate mass in grams to the diameter in millimeters is less than 0.6. 
     
     
         7 . The yoyo of  claim 1 , further comprising a string seat that surrounds the axle within the gap with a diameter greater than a diameter of the axle and about which the string is windable, wherein:
 the string seat comprises:
 a first drum included in the first body and at which inward ends of the multiple propeller blades of the first body terminate; and 
 a second drum included in the second body and at which inward ends of multiple second propeller blades of the second body terminate; 
   the first drum includes a portion that extends axially from the first body to the second drum; and   the second drum includes a portion that extends axially from the second body to the first drum.   
     
     
         8 . The yoyo of  claim 7 , wherein a diameter of the drum is at least 25% of a diameter of the first and second bodies. 
     
     
         9 . The yoyo of  claim 1 , wherein a length of the string is at least four feet. 
     
     
         10 . The yoyo of  claim 9 , wherein a length of the string is at least ten feet. 
     
     
         11 . The yoyo of  claim 1 , wherein a diameter of the outer rim is at least fourteen centimeters. 
     
     
         12 . The yoyo of  claim 1 , wherein at least one of the first or second bodies comprises a core of a first relatively hard material with a coating of a second material that is softer than the first relatively hard material. 
     
     
         13 . The yoyo of  claim 1 , further comprising a removable mass removable from and couplable to at least one of the first or second bodies to adjust a mass of the yoyo. 
     
     
         14 . The yoyo of  claim 1 , wherein at least one of the first or second bodies includes a light emitter element. 
     
     
         15 . A yoyo, comprising:
 a first body rotatable about an axis of rotation and that includes:
 a first outer rim; and 
 multiple first propeller blades that extend radially inward from the first outer rim; 
   a second body coupled to the first body, rotatable about the axis of rotation, and that includes:
 a second outer rim; and 
 multiple second propeller blades that extend radially inward from the second outer rim; and 
   a string seat that axially separates the first body from the second body and about which a string is windable and unwindable to cause rotation of the yoyo about the axis of rotation.   
     
     
         16 . The yoyo of  claim 15 , wherein:
 a ratio of an aggregate mass in grams of the yoyo to a diameter in millimeters of the first and second rims of the first and second bodies is less than 0.6; and   a diameter of the string seat is at least 25% of a diameter of the first and second rims of the first and second bodies.   
     
     
         17 . The yoyo of  claim 15 , further comprising an axle that defines the axis of rotation and to which each of the first and second bodies is coupled, wherein the string seat comprises a portion of the axle positioned within a gap between the first and second bodies. 
     
     
         18 . The yoyo of  claim 15 , wherein:
 the first body further includes a first drum at which inward ends of the multiple first propeller blades of the first body terminate;   the second body further includes a second drum at which inward ends of the multiple second propeller blades of the second body terminate;   the first drum includes a portion that extends axially from the first body to the second drum;   the second drum includes a portion that extends axially from the second body to the first drum; and   the string seat comprises a portion of the first drum and a portion of the second drum positioned within a gap between the first and second bodies.   
     
     
         19 . The yoyo of  claim 15 , wherein:
 at least one of the first or second bodies comprises a core of a first relatively hard material with a coating of a second material that is softer than the first relatively hard material;   the yoyo further includes a removable mass removable from and couplable to at least one of the first or second bodies to adjust a mass of the yoyo;   at least one of the first or second bodies includes a light emitter element; and   a length of the string is at least ten feet.   
     
     
         20 . A yoyo, comprising:
 a first body rotatable about an axis of rotation and that includes:
 a first hub; and 
 multiple first propeller blades that extend radially outward from the first hub; 
   a second body coupled to the first body, rotatable about the axis of rotation, and that includes:
 a second hub; and 
 multiple second propeller blades that extend radially outward from the second hub; and 
   a string seat that axially separates the first body from the second body and about which a string is windable and unwindable to cause rotation of the yoyo about the axis of rotation.