| 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} |
| 548 | DD | .~.~ By electromechanical step-advancing mechanisms (independent clocks or watches incorporating a stepping motor subclass 490; stepping motors in general H02K 33/00) [G04C 13/10] {2} |
| 550 | | .~.~.~ With rotating armature [G04C 13/11] |