Changing centre of gravity of object, eg sports racket, bat or club

摘要

The centre of gravity of eg a racket, a table tennis bat, a baseball bat or a golf club, is altered automatically during the swing to provide greater impact force on a ball. The object being swung incorporates a hollow tube 40, a base seat 30 at the handle end of the tube, an elastic element 20 and a weight 10, the act of swinging providing centrifugal force to overcome the elastic restraint and allow the weight and thus the centre of gravity to move further along the tube (Fig 3, not shown); the elastic force restores the weight to the starting position on completion of the swing. Preferably the weight takes the form of a plurality of spheres 11 wound together with wire 12; two separate hollow tubes with weights can be incorporated into a tennis racket frame (Figs 5 and 6, not shown).