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Chart device

  • US 4,023,290 A
  • Filed: 06/18/1976
  • Issued: 05/17/1977
  • Est. Priority Date: 01/21/1974
  • Status: Expired due to Term
First Claim
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1. A display system comprising a board of a substantially rectangular configuration having a pair of opposed major faces, a major portion of said board being formed of a nonmagnetic material, a minor portion of said board being of a ferromagnetic material, said ferromagnetic material extending circumferentially of said nonmagnetic material on at least one of said major faces, at least said one major face being of a relatively flat and planar nature, at least one underlay sheet of a nonmagnetic polyester material adapted to be placed in juxtaposition to said one major face, said underlay sheet being sized to extend to said ferromagnetic circumferential portion, at least one overlay film of a nonmagnetic polyester adapted to be placed on top of said underlay sheet, said overlay film being sized to extend to said minor circumferential portion of a ferromagnetic material, said overlay film being of a relatively transparent material and being adapted to receive markings from a marking device, and retaining means, said retaining means comprising a plurality of pieces of permanently magnetic material, each of said pieces being of a flexible resinous material having a pair of spaced-apart north and south poles extending longitudinally thereof, each piece having polarity identifying means on one edge thereof, said magnetic retaining means adapted to retain said underlay sheet and said overlay film in juxtaposition to each other and to said one major face by cooperating in a magnetic manner with said ferromagnetic material forming the minor portion of said board, at least a pair of guiding markers, each of said guiding markers being of a permanently magnetic material of a rectangular configuration, each of said markers having a pair of longitudinally extending poles on major surfaces thereof, one surface having poles of a relatively weak nature and the other of the surfaces having poles of a relatively strong nature.

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