Folding inner steel mould

The utility model discloses a folding inner steel mould, which mainly comprise steel molding boards. The utility model is characterized in that two upper steel molding boards and a mandril form a gemel shape, the inside of the lower molding board is provided with a small carriage, the lower part of the small carriage is provided with a screw mechanism, the bottom of the small carriage is provided with pulleys, and a track is arranged on the lower part of the steel molding board corresponding to the pulleys. The two ends of a connecting rod respectively connect with the upper part of the screw mechanism and the lower part of the steel molding board in the rotatable method. The utility model has rational structure and ingenious design; is applicable for the large-size hollow concrete components with small outer injection opening and big inner hole; and is folding, detachable and reusable. The utility model can overcome the defects that the prior art has poor appearance quality, complex and trivial operation, low utilization rate, great timber waste, and high cost. The utility model has great popularization value.