Freelancer :
aanyuliansyah87
I Try My Best
ٱلسَّلَامُ عَلَيْكُمْ وَرَحْمَةُ ٱللَّٰهِ وَبَرَكَاتُهُ 3D View Link : https://a360.co/3nMcLQQ Animation Video : https://youtu.be/cJnFsZUab3A Hello, my name Aan. im from Indonesia this is one of my design to solve your problem, we can adjust any size and shape to make it perfect, i can send you stl file, for make prototype using 3D Printer before continue to mass product. This design takes advantage of the weight of the manhole cover, and automatically folds down due to gravity when the manhole cover is opened send me text. Best regard Aan