PROBLEM TO BE SOLVED: To provide, as a hollow frame body for skeleton used for a skeleton of an agricultural greenhouse, a large-sized tent, etc., a hollow frame body for skeleton which can be bent smoothly and surely and can suppress a decrease in rigidity of a bent region as much as possible.SOLUTION: A hollow frame body for skeleton is shaped by crushing a pipe body into a sectionally inverted triangular shape, and has a left flange part 2 crushed such that inner surfaces of the pipe body come into contact with each other, a similar right flange part 3, and a downward projection part 4 which has an acute angle in a downward direction. The lower projection part 4 and left flange part 2 are connected by a left curved part 5 which is curved inward in the pipe body, and the lower projection part 4 and right flange part 3 are connected by a similar right curved part 6 so as to form a space 7 which is sectioned in an inverted triangular shape inside. When bent downward, the left curved part 5 and right curved part 6 move in the space 7 to be drawn in increasing in curvature at the bent region, and the lower projection part 4 moves upward.SELECTED DRAWING: Figure 3【課題】農業用ビニールハウスや大型テント等の骨格に用いられる骨組用中空フレーム体であって、屈曲させた際、無理なくスムーズに屈曲でき、且つ屈曲部位における剛性低下を可及的に抑制できる骨組用中空フレーム体を提供する。【解決手段】パイプ体を断面逆三角形状に潰して成形され、パイプ体の内面同士が接するように潰された左フランジ部２と、同様の右フランジ部３と、下向きに鋭角な凸状の下凸部４とを有し、下凸部４と左フランジ部２とが、パイプ体の内方に湾曲された左湾曲部５によって接続され、下凸部４と右フランジ部３とが、同様の右湾曲部６によって接続され、内部に、断面逆三角形状の空間７が形成され、下向きに曲げられたとき、その屈曲部位ｂにおいて、左湾曲部５および右湾曲部６が曲率を高めつつ引き込まれるように空間７の内部に移動し下凸部４が上方に移動する。【選択図】図３
