US 3745563 A
Description (OCR text may contain errors)
United States Patent 1 Jones et al.
m1 3,745,563 51 July 10,1973
[ ARRANGEMENT FOR PRESERVING THE FREE ROTATABILITY OF THE INDIVIDUAL VANES IN COMPOSITE DISPLAY DEVICES  Inventors: Charles E. Jones, Lincolnwood, lll.; William Ross Aiken, Los Altos Hills, Calif.
 Assignee: Display Technology Corporation,
 Filed: Jan. 10, 1972  Appl. No.2 216,360
 US. Cl. 340/378, 40/28 C, 40/130 J  Int. Cl. 609i 9/30  Field of Search 40/28 C, 130 J;
 References Cited UNITED STATES PATENTS 2/1913 Newell, Jr. 40/28 C Primary Examirier.lohn W. Caldwell Assistant Examiner-Marshall M. Curtis Att0rney-Kurt A. Tauchen 57 ABSTRACT In composite display devices of the rotatable vane type wherein rows of juxtaposed vanes are rotatably supported upon common horizontally disposed axles and are selectively tum'ed on said axles under the influence of electrostatic fields, coacting guide means are provided on the vanes and the support structure for the axles, for confining each vane during its performance to its predetermined position axially of its axle. Thus, displacement and lateral contact of adjacent vanes on the axles with resultant impairment of their free individual rotatability is prevented without need to use spacer beads between them.
5 Claims, 6 Drawing Figures PATENIEU JUL 1 0I975 SHEET 1 BF 2 ARRANGEMENT FOR PRESERVING THE FREE ROTATABILITY OF THE INDIVIDUAL VANES IN COMPOSITE DISPLAY DEVICES The present invention relates to adjustable display devices of the type composed in the manner of a mosaic of a plurality of juxtaposed and superposed individually adjustable display units each so constructed that sheet-like vanes may selectively be set to display or read positions wherein they present one of two surfaces to the viewer, or an erase position wherein they present one of their edges to the viewer and are, therefore, practically invisible. An example of a display device of this type is disclosed in U.S. Pat. No. 3,089,120. The required movements of the vanes about their axis of rotation may be effected by electrostaticforces, such as described in the mentioned U.S. Pat. No. 3,089,120.
For reasons of simplicity the vanes of a horizontal row of juxtaposed display units may be hingedly supported side by side upon a common, horizontally disposed axle or hinge rod. This practice, however, has introduced problems of its own. The individual vanes may shift upon the axles relative to one another, their side edges may come into contact with each other and obstruct, or at least impair, their individual movability, and the vertically superposed vanes in superposed rows of display units may lose precise vertical alignment with each other, thus rendering the whole display apparatus unsightly. Attempts have been made to avoid these malfunctions by interposing spacer beads or washers upon the axles between the edges of adjacent vanes, but the results are not satisfactory. The beads or washers interfere with the free movability of the individual vanes, especially when whole groups of vanes upon a common axle shift laterally in one direction, and the pressure of several such displaced vanes upon an adjacent vane that did not shift, becomes cummulative; and the interposition of beads or washers between adjacent vanes does not necessarily maintain precise vertical alignment between corresponding vanes in the superposed rows of a display device of the type here under consideration. Last but not least, the interposition of spacer beads and washers places an increased load on the free rotatability of the adjacent vanes and increases very considerably the complexity of the assembly.
It is an object of the present invention to provide a composite display device, of the type here under consideration wherein the free individual movability of all the adjustable vanes is at all times assured.
Another object of the invention is to provide a display device, of the type referred to, wherein the corresponding display vanes in superposed rows of individual display units remain at all times precisely aligned vertically.
Still another object of the invention is to provide a display device of the type referred to that is of simple and inexpensive construction and which is easy to assemble.
These and other objects of the present invention will be apparent from the following description of the accompanying drawings which illustrate certain preferred embodiments thereof and wherein FIG. 1 is a fragmentary front elevation of a display device embodying our invention;
FIG. 2 is a fragmentary perspective, viewed from the rear, of one of the vanes of the device shown in FIG.
FIG. 3 is a vertical section through the device taken along line 33 of FIG. I and viewed in the direction of the arrows associated with said line;
FIG. 4 is a side elevation, similar to FIG. 3, representing a modified embodiment -of the invention;
FIG. 5 is a perspective of the embodiment of the invention shown in FIG. 4 viewed from the rear of the display vane, and
FIG. 6 is a fragmentary front elevation of a vane of this device of the invention viewed in the direction of the arrow 6-6 in FIG. 4.
In accordance with the invention we'provide between each individual vane and the stationary support structure of the composite display device coacting guide means that confine each vane to its predetermined horizontal position axially of the common axle. In this manner the edges of adjacent vanes upon a common axle are at all times properly spaced, and thoughthe spacing may be minute, adjacent vanes can never come in contact with ach other, and impair their individual performance. Also, the described guide means between the stationary supporting structure of the display device and the individual vanes assures at all times that the corresponding vanes in superposed rows of the display device remain in precise vertical alignment.
Having reference to FIGS. 1, 2 and 3 the reference numeral 10 designates sheet-shaped vanes or flags of sheet material, such as aluminum foil. In the preferred embodiment of the invention these vanes are of square shape and their front surfaces 12 are painted in black or a dark color. In composite display devices of the type briefly described hereinbefore a row of horizontally juxtaposed vanes 10 is hingedly supported upon a common horizontally disposed axle or hinge rod 14 by means of bearings 16a and 1612 located at either'side of the vanes; they are individually movable between an upright position wherein they present their dark surface to an observer in front of the display device and an approximately horizontal or lying-down position wherein they present their front edge 18 to the observer and are therefore practically invisible to him. In the preferred embodiment of the invention which we are about to describe, the described movement of the vane is effected by vane-attracting electrostatic forces exerted upon the vane, for instance, by an electrode 20 located on the underside of a support arm 22 that projects outwardly from a common supporting structure 24. Whenever the electrode 20 in energized, the electrostatic field established by said electrode pulls the vane 10 upwardly into a substantially horizontal position wherein it presents its top edge 18 to an observer in front of the display device and is therefore practically invisible to him. This position is called the erase" position of the individual display unit. Deenergization of electrode 20 allosw the vane 10 to swing downwardly under the force of gravity into an upright display position determined by energization of another vane-attracting electrode 26 supported on the upper edge of another arm 22 located below, and identical in shape with, the first mentioned arm 22. In this position the vane presents its dark outer surface to the observer in front of the display device, for which reason this position is known as the display" or read position of the individual display unit.
As indicated in FIG. 1, several horizontal rows of juxtaposed display vanes may be arranged above and/or below each other, with corresponding vanes in the superposed rows in precise vertical alignment with one other; and by placing selected vanes into display position while keeping the remaining vanes in erase position, letters, symbols and messages may set up in dark color upon the display area formed by the front surface of the device against the background of the device, which is visible behind the vanes in erase position and whichis usually given a bright appearance.
In accordance with the embodiment of the invention illustrated in FIGS. 1 to 3 each of the vanes 10 is provided with a slot 28 whose side edges extend normal or perendicular to the axis of rotation of the vane; and slidably engaged into said slot is the free end 30 of the hereinbefore mentioned arm 22 of the common support structure 24. The end 30 of arm 22 of the support structure 24 and the side edges of slot 28 in the vane 10 constitute guide means whether the vane is in motion or in one of its positions of rest, that confine the vane precisely to its position axially of the hinge axle 14 so that the vanes cannot shift on the axle and come into contact with each other and block or impair their free individual movability. Also, due to the described guide means 28/30, the vertically aligned vanes in superposed rows remain in precise alignment with each other so that the composite display device of the invention re tains its neat and orderly appearance for extended periods of time in spite of rugged conditions of use and hard wear.
The tips 30 of arms 22 are arranged to protrude through the guide slots 28 in the vane, and the common axle 14 of a row ofjuxatposed vanes 10 is held in said protruding tips 30 of arms 22 (FIGS. 2 and 3). The proximity of the hinge axle to the contact area between the end 30 of arm 22 and the confining guide sides of slot 28 provides a leverage advantage that minimizes the danger of the vane clinging frictional to the tip 30.
In the embodiment of the invention illustrated in FIGS. 4, 5 and 6 the co-acting guide means between the vane 10 and the support structure 24' of the display device are formed by a pair of lugs or ears 40a and 40b on the back of the vane 10', i.e. the surface opposite to the display surface, which present to the tip 30' of the support arm 22 two axially spaced guide surfaces, that extend in planes pe pendicular to the axis of rotation. For smooth operation of the vane the tip 30' of the support arm 22 is semicircular, and the common axle 14 for all the vanes in a row ofjuxtaposed vanes passes for support through an orifice around the geometrical centre of the circle defined by the semi-circular ends 30' of the arms 22. In FIG. 4 the reference numerals and 26 designate the erase electrode and the display electrode, respectively, corresponding to electrodes 20 and 26 of the embodiment of the invention represented by FIGS. 1, 2 & 3 and the reference numeral 42 identifies a spacer element on the back of the vane 10 that strikes against support 22 when the vane swings into its erase position, and prevents contact between the conductive vane and the energized electrode, and sets the vane to a precisely horizontal position.
By the guide means of the invention as exemplified by the embodiments of the invention illustrated in FIGS. 1 to 6 free individual moveability of the vanes on a common axle and precise alignment of corresponding vanes in superposed horizontal rows are assured. Adjacent vanes cannot come into contact with each other, and spacers between adjacent vanes which place a load on adjacent vanes, that impairs their rotatability, may now be dispensed with.
While we have explained our invention with the aid of certain preferred embodiments thereof, it will be understood that the invention is not limited to the specific constructional details shown and described by way of example which may be departed from without departing from the scope and spirit of the invention.
1. In a display device of the type controlled by electrostatic fields the improvement comprising a support structure, a plurality of coplanar parallel axles held in said support structure, a plurality of vanes rotatably supported side by side from each of said axles, electrostatic electrode means for turning said vanes individually on said axles, and coacting guide means on both said support structure and each of said vanes in centeral areas thereof for confining said vanes individually to predetermined positions axially of said axles.
2. A display device according to claim 1 wherein said coacting guide means comprises a slot within a central area of each of said vanes having side edges lying in axially spaced planes normal to the axle for the vane and a projection of said support structure slidably engaged in said slot.
3. A display device according to claim 2 wherein the end of said projection protrudes through said slot and said axle is supported in the outwardly projecting end thereof.
' 4. A display device according to claim 1 wherein said co-acting guide means comprise axially spaced lugs projecting from a central area of a surface of said vane and a projection of said support structure slidably engaged in the space between said lugs.
' 5. A display device according to claim 4 wherein said axle is supported in said projection near the end thereof and the end edge of said end is semicircular with the center of its circle substantially coincident with the axis of said axle.