Plastics back skeleton of seat

The utility model provides a plastics back skeleton of seat, include: the back main part, the back main part includes first stand and second stand and connects first stand and the intermediate zone section of second stand, a pair of reinforcement, the reinforcement set up respectively in the inboard of first, the second stand of back main part, still include: connect the nut of back main part and reinforcement, the nut has a tubulose portion and passes through spaced apart main aspects flange and the tip flange of this tubulose portion, wherein, the back main part is moulded plastics around assembly nut and reinforcement together by a polymeric material and is formed, the main aspects flange of nut insert and put in between the stand and reinforcement of back main part, the tip flange is followed the reinforcement deviates from the one end of back main part is stretched out. This plastics back skeleton of seat has the part of reduction and lighter weight to have the streamlined and gratifying outward appearan