As the performance of the belts is not good, use of wire could be a solution for not causing slipping and extension. Besides, for a better safety system, we changed the design. The gearbox is connected directly to the handle so while turning the handle the gearbox would drive the furnace to rotate. As the gearbox is a worm-and-wheel type, the furnace cannot rotate anymore if the handle stops turning. Therefore, it is safer.