19 750 ViewsSomething very strange is going on in recent years in the atmosphere on the planet Whether it comes to aliens, changes in the earth’s core or CHEMTRAILS, HAARP?UFO. People all around the world take photos of this strange phenomena. Why are they appear and what is the meaning of them? What is going on? […]
Crane history The lifting mechanism is a wheel set.
8 990 Views“The stepping wheel was first mentioned in chronicles in 230 BC. Until the second half of the 19th century, it remained the important element of cranes. Such a wheel usually had a diameter of 4 to 5 meters, and had a mechanical advantage over a winch or capstan because of the larger radius of […]
