If these straps are just fixed to the roof, they may be easily damaged when the roof removed and put somewhere. So I made them movable. I made bearings from 5x5mm styrene square rod and installed on both ends of the strap rods to allow the straps freely swang.
屋根に付けるときただ単に固定すると屋根をはずして置いたとき破損しそうです。で、両側に5x5mmのスチロール角棒で作った軸受けを取り付け可動式としました。