The size and load-bearing capacity of a screw jack are directly related, but even a jack with a load capacity of 100 tons is within the range of human lifting operations. Why is this jack small in size yet capable of lifting heavy objects weighing hundreds or even thousands of tons?

The force of lifting heavy objects with a screw jack comes from its internal ratchet and pawl device. By lifting the nut sleeve with a screw, small rotational force can be converted into larger axial force. With this labor-saving jack, we can lift heavy objects weighing up to 100 kilograms with 1 kilogram of force, which is similar to the "four or two turns a thousand pounds" in Tai Chi.

Since the force of the screw jack is infinite, does it mean that it has no ceiling in lifting heavy objects? Actually, it's not like that, because there is a more powerful hydraulic press in the world, which is a mechanical device. When the two are lifted and pressed against each other in the lifting state, the jack will also fail and slowly be crushed by the hydraulic press.