To simplified the designing, diagram presentation, construction and profile of helicoidal stair, the formation of helicoid is analyzed, and it's mathematical model is studied.
为简化旋转楼梯的设计、图示、施工及剖面形状，对螺旋面的形成进行了分析，建立了螺旋面的数学模型。
2
The utility model discloses a rechargeable lamp, including a cylindrical lamp holder, a helicoidal socket, a holder motherboard, a conduction metal sheet and a storage battery.