Aircraft safety coupling

Claim 1

A SAFETY COUPLING FOR AN AIRCRAFT POWER PLANT HAVING AN ENGINE AND A PROPELLER INCLUDING, AN ENGINE DRIVEN SHAFT, AN INTERMEDIATE SHAFT OPERATIVELY CONNECTED TO SAID PROPELLER, A HOUSING INTO WHICH BOTH OF SAID SHAFTS EXTEND, SAID HOUSING BEING PARTIALLY FILLED WITH HYDRAULIC FLUID, A FIRST COUPLING DISC CONNECTED TO ROTATE WITH SAID ENGINE DRIVEN SHAFT, A SECOND COUPLING DISC CONNECTED TO ROTATE WITH SAID INTERMEDIATE SHAFT, SAID FIRST AND SECOND COUPLING DISCS HAVING EXTERNAL HELICAL SPLINE TEETH OF THE SAME LEAD BUT OPPOSITE HANDS, A COUPLING ANNULUS HAVING SPACED SETS OF INTERNAL HELICAL SPLINE TEETH OF THE SAME LEAD BUT OPPOSITE HANDS NATING RESPECTIVELY WITH THE EXTERNAL HELICAL SPLINE TEETH OF SAID COUPLING DISCS, RESILIENT MEANS REACTING AGAINST SAID COUPLING ANNULIUS FOR MAINTAINING SAID COUPLING DISCS ENGAGED WITH SAID COUPLING ANNULUS TO TRANSMIT POWER FROM SAID ENGINE DRIVEN SHAFT TO SAID INTERMEDIATE SHAFT, SAID HELICAL SPLINE TEETH INTERACTING TO OVERCOME SAID RESILIENT MEANS AND DISENGAGE SAID FIRST COUPLING DISC FROM SAID COUPLING ANNULUS IN RESPONSE TO A PREDETERMINED TORQUE TRANSMITTED FROM SAID INTERMEDIATE SHAFT TO SAID ENGINE DRIVEN SHAFT, AND CENTRIFUGALLY ACTUATED HYDRAULIC MEANS REACTING AGAINST SAID COUPLING ANNULUS FOR MAINTAINING SAID FIRST COUPLING DISC IN AN ANTI-RATCHETING POSITION.