| 摘要 |
An apparatus for displaying patterns of balls forming a Braille-sign or other symbol or picture, comprise a driven running belt carrying the balls with it. According to the invention the belt is smooth-instead of being perforated-whereby the balls may be grouped upon the belt in arbitrary mutual positions. The balls are kept in place by being clamped against said belt by means of a second belt and due to the spaces between the two belts being maintained at a reduced air pressure. |
