Lifter with electropermanent magnets provided with a safety device
November 30, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesPermanent magnet holding system Safety device for lifting magnets Magnetic levitation apparatus and method Magnetic gripping apparatus having circuit for eliminating residual flux Permanent magnetic retaining device to move, affix or carry ferromagnetic parts or loads with electronic switching of the magnetic flux to release the carried load Magnetic holder for contact sensor Patent #: 5642089 InventorAssigneeApplicationNo. 194392 filed on 11/30/1998US Classes:335/289, Electromagnet type (e.g., electromagnetic chuck)335/291Lifting or attracting type (e.g., for lifting pigiron or pulling hairpins)ExaminersPrimary: Donovan, LincolnAttorney, Agent or FirmForeign Patent References
International ClassH01F 007/20AbstractA lifter comprising at least a reversible magnet (5, 5') arranged with its polarities oriented along a vertical axis above at least a magnet (6, 6') provided with at least a pair of permanent magnets (6a, 6a') arranged with the polarities oriented along an horizontal axis on the sides of at least a ferromagnetic core (6b, 6b') suitable to contact the load (18) to be lifted, at least a magnetic sensor (11) arranged close to the base (6c, 6c') of said ferromagnetic core, and a further magnetic sensor (12) arranged over said permanent magnets (6a, 6a') so as to measure substantially only the magnetic flux passing through the reversible magnet (5, 5'), as well as a safety device (13) for processing the signals transmitted by said magnetic sensors (11, 12) and obtaining the working point of the lifter on the magnetization curve (14) of the reversible magnet (5, 5'). | |
