Extendable and Retractable Tennis Racquet

Abstract

One embodiment of an extendable and retractable tennis racquet contains a stringed area 01, throat 02, and shank 03 as one integral member. The handle is comprised of a shank inside of a hollow handle 05. A spring or flexible means 07 connects the shank to the hollow handle. When the racquet is swung, the centrifugal force generated pulls on the head assembly. The shank slides outward telescopically, thereby increasing the length of the racquet. At the end of the racquet swing, the restoring force of the spring overcomes the diminishing centrifugal force, which pulls the shank back to its retracted position. Other embodiments are described and shown.

We claim: 
     
         1 . A tennis racquet having the means to extend and retract, comprising:
 a stringed frame head with a throat;   a shank connected to said throat;   a handle;   means for joining said shank and said handle telescopically, allowing only a relative sliding motion in the longitudinal direction; and   a spring or flexible means to connect both said shank and said handle to prevent said shank to detach from said handle longitudinally.   
     
     
         2 . The tennis racquet of  claim 1 , wherein said stringed frame head, throat and shank are one integral member. 
     
     
         3 . The tennis racquet of  claim 1 , wherein said shank and said handle are comprised of complex cross-sections to increase stiffness. 
     
     
         4 . The tennis racquet of  claim 1 , wherein said handle has a cavity means to accept a portion of said shank. 
     
     
         5 . The tennis racquet of  claim 4 , wherein said spring or flexible means connects to the inside bottom of the cavity of said handle and base of said shank. 
     
     
         6 . A tennis racquet having the means to extend and retract, comprising:
 a stringed frame head with a throat;   a shank connected to said throat;   a handle;   means for joining said shank and said handle telescopically, allowing only a relative sliding motion in the longitudinal direction;   a spring or flexible means to connect both said shank and said handle to prevent said shank to detach from said handle longitudinally; and   a mechanical stop means between the said shank and said handle.   
     
     
         7 . The tennis racquet of  claim 6 , wherein said stringed frame head, throat and shank are one integral member. 
     
     
         8 . The tennis racquet of  claim 6 , wherein said shank and said handle are comprised of complex cross-sections to increase stiffness. 
     
     
         9 . The tennis racquet of  claim 6 , wherein said handle has a cavity means to accept a portion of said shank. 
     
     
         10 . The tennis racquet of  claim 9 , wherein said spring or flexible means connects to the inside bottom of the cavity of said handle and base of said shank. 
     
     
         11 . A tennis racquet having the means to extend and retract, comprising:
 a stringed frame head with a throat;   a shank connected to said throat;   a handle;   means for joining said shank and said handle telescopically, allowing only a relative sliding motion in the longitudinal direction;   a pinion gear mounted to said handle;   a rack gear mounted to said shank; and   a torsion spring connecting to both said pinion gear and said handle; and said pinion gear is engaged to said rack gear.   
     
     
         12 . The tennis racquet of  claim 11 , wherein said stringed frame head, throat and shank are one integral member. 
     
     
         13 . The tennis racquet of  claim 11 , wherein said shank and said hollow handle are comprised of complex cross-sections to increase stiffness. 
     
     
         14 . The tennis racquet of  claim 11 , wherein said handle has a cavity means to accept a portion of said shank. 
     
     
         15 . The tennis racquet of  claim 11 , wherein said pinion gear is mounted to the shank; said rack gear is mounted to said handle; and said torsion spring connecting to both pinion gear and said shank. 
     
     
         16 . The tennis racquet of  claim 1  further including a mechanical stop means between the said shank and the said handle. 
     
     
         17 . The tennis racquet of  claim 1 , wherein the said spring or flexible means is a torsional spring; and the said torsional spring connecting to the said handle via a pinion gear and a rack gear.