Magnetic capture is designed for the safe movement of goods from ferromagnetic metals - steel sheets, round blanks, shaped tubes, cast iron frames and so on. The strength of the magnetic field raises any parts, machines, mechanisms that have a flat or rounded surface. The scope of their application is great - from moving products around the workshop to unloading vehicles. The advantage of such gripping devices is the acceleration of the slinging processes, in contrast to the traditional methods of transportation with hooks, chains, and other rigging. PML-grips reliably fix the load, do not damage its surface, compact, almost independent of operating conditions.
Device classification
Magnetic lifting devices are manual, pulsed and automatic. Magnetic capture design is universal. But different models have distinctive engineering practices of the manufacturer. The heart of any PML type load capture device is a magnet based on an alloy of neodymium and rectangular iron, enclosed in a metal case. A removable sole with a flat or arched profile is attached to the magnet for pressing against a surface of various shapes. The housing has an earring or hinge bracket for mounting on a lifting mechanism or traverse, an eccentric axis, driven into rotation manually or mechanically. Automatic load grips are equipped with special steel plates that provide demagnetization.
Principle of operation
Unlike other metal grippers, the magnetic one works without a sling. With the help of the emerging magnetic field, the surface of the part is attracted to the lower part of the PML grip, securely fixing. The larger the area of the pressed surface, the stronger the emerging field. Dropping the transported parts is done by increasing the air gap between the part and the sole manually by turning the eccentric shaft. The automatic method of dropping occurs by opening the individual parts of the neodymium magnets and the lack of tension on the lines that secure the housing to the hook of the hoisting machine. In the latter case, a linkage is used.
Advantages and disadvantages
A plus of neodymium cargo captures is the saving of forces and time for transportation of goods, their unloading or supply to machines for further processing. These devices are universal, they are used for almost all types of alloys with ferromagnetic properties, they carry out the lifting of cargo of small and large tonnage in automatic or manual mode.
The working staff does not need additional qualifications associated with the study of the device. Its design is simple and operation is easy. The cargo capture itself can be used in workshops, warehouses, boxes of any type without connecting to electricity, on manual hoists, truck cranes, beam cranes. They are used in closed workshops, open warehouses, in any weather.
The disadvantages of magnetic load capture include a decrease in the force of attraction with increasing temperature of the part and an increase in the size and complexity of the structure with increasing load capacity.
Selection options
The main criterion for a load gripping device is its load capacity, but in the case of magnetic gripping the list of requirements is expanding. In general, the carrying capacity of the device depends on the area of contact with the load and the chemical composition of the magnetic alloy. The first question is solved in two ways - by choosing a large-area magnet to increase the clamping force or by buying several grippers of lower carrying capacity, used simultaneously on the traverse. This is relevant when transporting sheet metal, when the edges gradually “peel” from the base of the gripper when the web is bent. Therefore, the choice of the rated power of the magnet depends on the shape of the load.
The thickness of the metal being lifted and its temperature affect the parameters of the magnetic pickup selected. Since the properties of neodymium are lost during heating and with increasing distance from the center of gravity of the workpiece to the sole of the device.
When lifting goods, the safety factor for different types of metal is taken into account. PML type devices work with any surface roughness of transported goods.