| 968 / | HD | HOROLOGY |
| 564 | | INDICATING THE TIME OPTICALLY BY ELECTRIC MEANS (subclass 577 takes precedence; by mechanical means subclasses 139 and 162) [G04C 17/00] precedence; by mechanical means subclasses 139 and 162) [G04C 17/00] {6} |
| 565 | DD | .~> By hands [G04C 17/00B] {1} |
| 567 | DD | .~> By flaps [G04C 17/00F] {2} |
| 570 | DD | .~> By discs (by drums subclass 573) [G04C 17/00S] {1} |
| 573 | DD | .~> By drums or drumlike devices [G04C 17/00T] {1} |
| 575 | DD | .~> Combined electro-optical and electromechanical displays [G04C 17/00V] |
| 576 | DD | .~> By electric lamps [G04C 17/02] |