A proposed electromechanical display system would be capable of presenting as many as six distinct messages. This system would be a more capable and more complex successor to the proposed system reported in "Four-Message Electromechanical Display System" (MFS-31368), NASA Tech Briefs, Vol. 24, No. 4 (April 2000), page 32. In contrast to the now-proposed six-message system and the previously proposed four-message system, a typical conventional electromechanical display system is limited to three messages.

Figure 1. Adjacent Hexagonal Cylinders would be rotated to present any of six messages to viewerslooking at the front side.
The three-message limit arises as follows: A typical electromechanical display telesystem contains display elements with multiple flat faces that are rotated into view to present a message. Each display element can present, for example, an alphanumeric character or part of an image. If the display elements have flat faces, then the number of messages is limited to three because three is the maximum number of sides of a polygon that can be placed contiguously with other, identical polygons along a common baseline and that can be rotated without interfering with an adjacent polygon.

Figure 2. The Visible Face of Each HexagonalCylinder would effectively be expanded by rotationor sliding of panels.
In the proposed system (see Figure 1), each display element would include a cylinder having a regular hexagonal cross section. The adjacent elements would be positioned along a baseline with just enough room that each element could rotate without interfering with an adjacent element. As in the systems mentioned above, each face of each element would represent a portion of a message. Each element could be rotated to one of six equally spaced angular positions to present the desired portion of one of six messages. However, unlike in prior systems, merely orienting the desired faces to form a flat surface visible to intended viewers would not suffice to present the message because there would be large gaps between the faces of the aligned hexagons.

To enable filling of the gaps between the visible aligned faces of adjacent hexagons, the affected portions of the messages would be placed on panels that would be rotated or slid to effectively expand the visible faces to fill or nearly fill the gaps (see Figure 2). After presentation of a message, panels would be retracted, restoring the hexagonal outlines to enable rotation of the elements to display the next message. Optionally, panels on both the front and the back of the display could be extended simultaneously to present different front and back messages.

This work was done by Richard T. Howard of Marshall Space Flight Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanics/Machinery category. Refer to MFS-31576-1.