Abstract: A rotatable display or indicating element mounts a permanent magnet and is rotated greater than 90.degree. and less than 180.degree. between mechanical stops by an exterior pole piece of reversible polarity. A small permanent magnet adjacent the pole piece is designed with the locus of the rotatably mounted magnet to provide a stable position for the element just inward of the mechanical limiting position.

Abstract: A display element is mounted on a base to rotate less than 180.degree. between two limiting positions and to create mutually contrasting effects in the two positions. A magnetizable element mounted on the base extends parallel to the axis of rotation and exerts rotational torque at each of its free ends on one of two permanent magnets mounted on the display element to rotate outside of the free ends.

Abstract: A drive is provided for a rotatably mounted display element which is distinctively colored on opposite sides and having a magnet rotatable therewith defining a magnetic axis transverse to the axis of rotation, a pole piece of reversible permanently magnetizable material, designed so that the reversible field of said pole piece will produce opposite orientations of said display element, a coil for energizing said pole piece. There is provided means for determining from the characteristics of current resulting from voltage applied to said coil whether or not the polarity of said pole piece is being reversed.

Abstract: Blanking means operable voluntarily or in the event of power failure are provided for an electromagnetically operated display which comprises groups of rotatably mounted elements having opposed faces of contrasting colors, each element carrying a magnet rotatable therewith, the orientation of each element and the choice of contrasting color displayed thereby being determined by the magnetic field formed by an adjacent reversibly permanently magnetizable field forming member. A winding is provided corresponding to each field forming member located so that a pulse through said winding in a predetermined sense will magnetize said field forming member in a corresponding sense. Write circuit means interconnects the windings in such a group and connects them to a power source, the write circuit means being arranged so that the windings of individual elements may be selectively energized to display a desired pattern for said group.

Abstract: Clocking pulses are provided by providing a number of equally spaced potential mark locations serially disposed in the intended direction of relative movement of the marks past a detection location wherein there are provided marks contrasting with the background at every nth one of the potential mark locations and where marks are selectively provided or not at the other potential mark locations to provide information. Means are provided for detecting such marks or the absence thereof when the locations are moved relatively to said detecting means, in a relative direction to move serially therepast. At least n detectors are provided to disposed in said relative movement disposed so that all sense the status of a location simultaneously and at least one is sensing a mark at one of the `nth` locations.

Abstract: A magnetically operated display element comprises a disc of substantially non-magnetic material, provided on opposite sides with ears extending transversely in the same direction relative to the disc, said ears being designed to allow the pivotal mounting of said disc on supporting means. The disc is contrastingly colored on opposite surfaces and shaped so that concavities are provided as viewed on one of said surfaces, such concavities being on opposite sides of and defining on the surface on which they appear a ridge extending across said disc approximately parallel to the pivotal axis of the disc; the concavities and ridge appearing on the opposite surface as convexities and a valley.

Abstract: A disc rotatable to exhibit alternately one of its two faces under the influence of an external magnetic field, has its center of gravity offset with respect to the pivoting plane so as to ensure a positive torque when moving from either of its rest positions under the influence of the said magnetic field.

Abstract: A rotatable element for a display element is constructed of an open ring which supports a display surface resiliently bent from its unstressed attitude and held in such position. The element is designed to be pivotally mountable on an axis generally parallel to the mean plane of the display surface.The element is preferably magnetically operable by an exterior magnetic field and the element carries a magnet defining a field transverse to the pivotal axis.The exterior field for the rotatable element is preferably provided by a coil wound core resiliently mounted on the support surface for the element.The support surface provides brackets for location on each side of the element position and designed to receive a shaft mounting such elements.

Abstract: A middle tape punched to receive magnets is provided first with a tape on one side then with magnets in the punched apertures and then with a tape on the other side to provide a source of a series of magnetically actuable elements.

Abstract: A display or indicating device has an array of display elements rotatably mounted on one side of a board and electrically controlled means for actuating them, where the board is of the type on which printed circuits are mounted.

Abstract: A plurality of longitudinally extending mounting elements are designed to mount in a single row a plurality of magnetically actuable display elements. Each of the mounting elements is designed to be located side by side and in close proximity to other row mounting elements of the same type and at each end is provided with couplings designed to couple the element to a member extending transversely thereto. The coupling elements and the transversely extending member are so arranged that a plurality of the coupling elements located side by side may be coupled to the transversely extending member. Energizing windings for individual magnetic control of each of the display elements is provided rearwardly of the row elements. Thus the windings for all the row elements may be applied while the elements are arranged end - to - end and the elements may then be rotated parallel to each other, with the windings attached for assembly to the transverse member.