| 968 / | HD | HOROLOGY |
| 524 | DD | DRIVING MECHANISMS FOR CLOCKS BY MASTER CLOCKS [G04C 13/00] {2} |
| 547 | DD | .~ Slave clocks actuated intermittently [G04C 13/08] {3} |
| 551 | | .~.~ By continuously rotating electric motors (independent clocks subclass 493; clocks driven by synchronous motors subclass 553) [G04C 13/12] |