The permanent magnetic lifter is designed by using the principle of continuity of magnetic flux and the principle of superposition of magnetic fields. Through the relative movement of the magnetic system, the magnetic field strength on the working pole can be increased or removed to achieve the purpose of working and unloading.

The permanent magnetic lifter is made of high performance permanent magnetic material, which can produce a strong pull force in the magnetic circuit. It can be rotated by the handle to change the magnetic line of force to make the lifter work or shut down without external power supply, which is a new lifting tool with both safety and energy saving and high efficiency.

Its working principle is shown in the figure, when the lifter magnetic pole is in the state of figure a, the magnetic line of force comes out from the N pole of the magnet, passes through the magnetic yoke, passes through the ferromagnetic workpiece, and then returns to the magnetic yoke into the S pole of the magnet. In this way, the workpiece can be firmly sucked on the working pole surface of the lifting crane. When the magnetic pole in the state of Figure b, the magnetic lines of force less than the working pole surface of the lifter in the internal closed circuit, almost no magnetic lines of force from the working pole surface of the lifter out, so the workpiece will not produce suction, you can successfully achieve unloading.