在20世纪50年代以前,那时的足球与现在有所不同,它是球的外壳上有一个小口以塞入球胆,灌气的入口是胆上的长颈,灌气后将胆口系牢并塞入壳内,用牛皮筋扎紧。自发明了气眼球后,可经由气眼直接向球胆灌气。现在的足球外壳是用熟皮做成,表面上是不得附加任何物质的(如尼龙套等),球内装有橡皮胆。 Before the 1950s, football was different from what it used to be: there was a small hole in the ball’s shell that was stuffed into the bladder. The entrance to the inflatable was a gutsy neck. After filling, the gall bladder Rigid and stuffed into the shell, with the tendon tied tight. Since the invention of the eyeball, can be inflated directly to the bladder through the eye. Now the football shell is made of cooked skin, the surface is not attached to any substance (such as nylon sleeve, etc.), the ball is equipped with rubber bladder.