In bearing spring point is due bedspring of steel bar consolidate, the fabric of fixed bedspring should be corroded not easily and insipidity, enclothe the fabric on bedspring Alexandrine character.

• 在承重弹簧处应有钢条加固弹簧，固定弹簧的织物应不易腐蚀且无味，覆盖在弹簧上的织物同上特性。