Lifting ferromagnetic material (e.g., sheet metal) using magnetic material is known. One system uses a ring magnet that is magnetized to have four alternating polarity quadrants and uses air pressure to lift the ring magnet within a cylinder to cause the cylinder to detach from ferromagnetic material.
Also known is a cam-based system that is applied to a fixture holding a magnetic structure made up of two discrete magnets arranged in an opposite plurality orientation. The cam system applies a force on one side of the fixture to cause an angled spacing between each of the two magnets and the ferromagnetic material causing the fixture to disengage from the ferromagnetic material.
Additionally, the use of magnetic structures comprising alternating polarity discrete magnet arrangement is known where the number of discrete magnets is selected to control the throw of the device so as to control the number of pieces of ferromagnetic material removed from a stack of ferromagnetic material. For example, four magnets arranged in a checker board like polarity pattern might be used to lift three pieces of ferromagnetic material while another arrangement of sixteen smaller magnets might be used to lift only one piece of ferromagnetic material.
Magnetic printers have been developed that are capable of magnetizing multiple magnetic field sources having polarity patterns into a single piece of ferromagnetic material. Such polarity patterns
USPTO Backgrounds
USPTO Backgrounds