| 摘要 |
PURPOSE:To make the rigidity of a reinforcement sphere large and prevent a bag body specific part alone being broken, by making the extension rate of reinforcement yarns forming a cloth reinforcement sphere at the bag body, smaller than those of longitudinal yarns and latitudinal yarns forming the neighbouring cloth. CONSTITUTION:Longitudinal yarns 1a and latitudinal yarns 3a using yarn materials having appropriate extension rates, are knitted by means of a predetermined knitting means. Meanwhile, reinforcement yarns 5 consisting of material whose extension rate is smaller than those of longitudinal and latitudinal yarns 1a, 3a, are formed of a longitudinal yarn portion 5a extending in parallel along yarns 1a at a cloth periphery edge portion neighbouring place and a latitudinal yarn portion 5b extending in parallel along yarns 3a. And respective interior angles theta1-theta4 formed between the portion 5a and the portion 5b and the cloth 1 respective a-d, are limited at not less than 35 deg. and not more than 55 deg.. As a result, an approximately correct square reinforcement sphere 7 that continues with a predetermined width is formed at the circular shape cloth 1 periphery edge portion neibouring place. As a result, when a bag body is developed in expansion, even in a case in which partial stress is concentrated from the outside, it is prevented that the specific part alone of the bag body is broken. |
