| 968 / | HD | HOROLOGY |
| 553 | | CLOCKS DRIVEN BY SYNCHRONOUS MOTORS [G04C 15/00] {4} |
| 554 | DD | .~> Without power reserve [G04C 15/00B] {4} |
| 559 | DD | .~> With power reserve [G04C 15/00C] |
| 560 | DD | .~> Synchronous clock systems, e.g., provided with radiolink or using transmission of alternating current via existing power distribution lines, etc. [G04C 15/00H] {2} |
| 563 | DD | .~> Lubricating [G04C 15/00T] |