This invention relates to magnetic diagramming displays with movable-symbol pieces and more particularly to such displays which are capable of being supported in either a vertical or a horizontal position.
In one class of diagramming panel, there is a background design such as a football field or the like mounted to a ferromagnetic support. Movable-symbol pieces which may represent players on a football field or in the case of other background designs the appropriate movable pieces for the background are held magnetically in place.
In one type of prior art diagramming panel of this class, a ferromagnetic backboard has a diagram mounted to it, which for example, may be of a football field. The movable-symbol pieces include magnetic material and may, for example, represent football players which are held to the background. The players are moved by hand and it is possible to make other marks on the diagram. This type of panel is disclosed in U.S. Pat. No. 2,579,105.
Certain of the prior art panels of the above type have a disadvantage in that it is cumbersome to mark on the background panel. It is cumbersome because symbol pieces must first be moved and then the course across which they move traced. Erasure is difficult because the movable-symbol pieces are in the way and the entire operation is slow for illustrating purposes.
In one prior art type of diagramming panel of the above class, the magnetic symbol pieces also have mounted to them a marker so that, as the symbol pieces are moved, the path of their movement is marked on the overlying diagram. Such a prior art apparatus is disclosed in U.S. Pat. No. 1,927,695. While this type of diagramming panel has the advantage of being able to mark the path of the symbol pieces as they are moved, it has other disadvantages. One such disadvantage is that there must be a separate marker for every symbol piece and, whenever the symbol piece is moved, the mark is made.
One type of nonanalogous prior art is magnetic games which are generally played in a horizontal position and in which a magnet is used to move symbol pieces from place to place on a magnetic background with an overlying diagram. Generally, because these games cannot be mounted vertically and the paths of the symbol pieces are not traced, the games are not suitable for instructional or diagramming purposes.