Methods of Inflation and Play of Lightweight Training Ball with Inner and Outer Layers

Abstract

A lightweight play or training device includes an inflatable bladder and a two-piece molded polymer cover formed by first and second closed-cell foam half-shells fused together (e.g., by ultrasonic welding) along a continuous peripheral seam. The bladder, when unconstrained, is significantly larger than the internal volume of the molded cover so that upon inflation it bunches against the inner surface of the cover, thereby absorbing impact energy and slowing aerodynamic flight. Preferred foams have densities of 20 kg m−3 to 60 kg m−3 and Shore A hardness of 30-60. The device may include an integral inflation tube acting as a one-way valve and an optional elastic tether for solo skills practice. Variants include spherical balls and flying discs, as well as alternative seam geometries and joining techniques.

What is claimed is: 
     
         1 . A lightweight training device comprising:
 (a) an inflatable bladder having, when unconstrained, a maximum dimension DB;   (b) a first molded polymer half-shell and a second molded polymer half-shell, each defining an inner concave surface and an outward-facing playing surface;   (c) a fused peripheral seam joining the first and second half-shells to form an enclosure having a maximum internal dimension DC;   (d) wherein DB≥1.25×DC, and wherein inflation of the bladder within the enclosure causes at least a portion of the bladder to bunch against the inner concave surface; and   (e) wherein the half-shells are molded from a closed-cell polymer foam selected from polyurethane, polyethylene, EVA or mixtures thereof.   
     
     
         2 . The device of  claim 1 , wherein DB≥1.30×DC. 
     
     
         3 . The device of  claim 1 , wherein the fused peripheral seam is produced by ultrasonic welding. 
     
     
         4 . The device of  claim 1 , wherein the fused peripheral seam is produced by welding selected from hot-plate, spin, vibration, RF or laser welding. 
     
     
         5 . The device of  claim 1 , wherein the seam comprises a step-lap geometry. 
     
     
         6 . The device of  claim 1 , wherein the polymer foam has a density of 20 kg m −3  to 60 kg m −3 . 
     
     
         7 . The device of  claim 1 , wherein the polymer foam has a Shore A hardness of 30 to 60. 
     
     
         8 . The device of  claim 1 , further comprising a flexible inflation tube fixedly secured within a self-sealing valve of the bladder, the tube acting as a one-way valve when inserted therein. 
     
     
         9 . The device of  claim 8 , wherein the inflation tube is removable after inflation. 
     
     
         10 . The device of  claim 8 , wherein the inflation tube is integral and non-removable. 
     
     
         11 . The device of  claim 8 , wherein the inflation tube is composed of polyolefin or silicone elastomer and has a length between 20 mm and 60 mm. 
     
     
         12 . The device of  claim 1 , further comprising an elastic tether cord affixed to the fused seam.