Positive automatic dump body hoist safety lock

Claim 1

A POSITIVE AUTOMATIC HOIST SAFETY LOCK COMPRISING A TRUCK FRAME, A BOX FRAME, A HOIST FRAME MOUNTED ON THE TRUCK FRAME AND HAVING HYDRAULIC JACK MEANS ON THE HOIST FRAME TO RAISE THE BOX FRAME, A CHANNEL MOUNTED ON THE HOIST FRAME, A LOCKING BAR PIVOTALLY MOUNTED ON THE BOX FRAME AT ONE END THEREOF AND THE OTHER END SLIDABLY ENGAGING ALONG THE CHANNEL ON THE HOIST FRAME, SAID OTHER END HAVING A RECESS THEREIN AND CONTINUING ALONG SAID CHANNEL AS THE BOX IS RAISED BY THE HYDRAULIC JACK UNTIL THE BOX IS HOISTED, A LOCKING BOLT MOUNTED ON THE HOIST FRAME FOR ENGAING THE RECESS AT THE OTHER ON OF THE LOCKING BAR WHEN THE BOX IS HOISTED TO LOCK THE BOX IN THE HOIST POSITION, A HALF-MOON CAM PIVOTALLY MOUNTED ON SAID LOCKING BAR FOR RIDING OVER A BOLT ON THE HOIST FRAME, A STOP PIN MOUNTED ON THE LOCKING BAR TO LIMIT THE DISPLACEMENT OF SAID HALF-MOON CAM AND ALLOW THE LOCKING BAR TO OVERRIDE ENGAGEMENT OF THE LOCKING BOLT AND RETURN THE FREE END OF THE LOCKING BAR INTO SAID CHANNEL WHILE THE BOX IS BEING LOWERED ONTO THE HOIST FRAME.