Serial number printing apparatus

Claim 1

A PRINTING MECHANISM COMPRISING AN OPERATING LEVER HAVING A GIVEN REST POSITION AND ADAPTED TO HAVE LIMITED MOVEMENT IN A GIVEN PATH; A PRINT HAMMER UNIT ALSO MOUNTED FOR LIMITED MOVEMENT IN A GIVEN PATH; RESILIENT COUPLING MEANS BETWEEN SAID UNIT AND SAID LEVER AND ADAPTED TO STORE ENERGY WHEN RELATIVE MOVEMENT IN A GIVEN SENSE OCCURS BETWEEN SAID LEVER AND SAID PRINT HAMMER UNIT; A MOVABLE LATCH MEMBER NORMALLY POSITIONED TO PREVENT MOVEMENT OF SAID PRINT HAMMER UNIT WHEN RELATIVE MOVEMENT IN SAID GIVEN SENSE OCCURS BY DISPLACEMENT OF SAID OPERATING LEVER FROM SAID REST POSITION; PRINTING MECHANISM ADAPTED TO BE OPERATED BY SAID HAMMER UNIT; A LATCH RELEASE MEMBER EXTENDING FROM SAID OPERATING LEVER AT A GIVEN POINT THEREON FOR RELEASING SAID LATCH MEMBER ONLY AFTER SAID LEVER HAS UNDERGONE A PREDETERMINED DISPLACEMENT IN SAID GIVEN SENSE FROM SAID GIVEN REST POSITION TO PERMIT SAID PRINT HAMMERR UNIT TO BE MOVED INTO OPERATIVE RELATION WITH SAID PRINTING MECHANISM; AND MEANS FOR MOVING SAID OPERATING LEVER OUT OF SAID REST POSITION TO PRODUCE RELATIVE MOVEMENT IN SAID GIVEN SENSE BETWEEN SAID PRINT HAMMER UNIT AND SAID LEVER.