Gymnastic floor structure having vertical elasticity

Claim 1

A gymnastic floor structure comprising a panel board assembly composed of a plurality of rectangular unit panel boards closely connected with one another on a flat plane and connected by connecting means, lower floor members composed of a plurality of elastic support members which are spacedly secured to the bottom of said panel board assembly and placed on a gymnasium base floor to elastically repulse external forces such as jump forces applied onto said panel board assembly, an upper floor member placed directly on and in contact with substantially all of an upper surface of said panel board assembly to elastically support the external forces, said upper floor member comprising an elastic mat and a carpet placed on said mat, and said elastic mat is made of ethylene vinyl acetate resin foam modified by ethylene propylene rubber and butadiene rubber and functioning in cooperation with said carpet to elastically support external forces applied onto said carpet, and tightening means which prevent said unit panel board assembly from loosening in the connecting directions, wherein said elastic support members are made of ethylene vinyl acetate resin foam modified by ethylene propylene rubber and butadiene rubber having a multiplying factor of 5 to 6, said connecting means have an almost l-shaped cross section composed of two U-shaped channels integrated back to back, one channel of said connecting means is used as a fixing part and the other channel is used as a fitting part, between two adjacent unit panels, said fixing part of said connecting means is to fit to the side edge portion of one unit panel board and secured with fastening means, and said fitting part is fitted to the side edge portion of the other unit panel board.