Hydraulically actuated dock board with hinged lip

Claim 1

A HYDRAULICALLY ACTUATED DOCK BOARD COMPRISING: A FRAME MEANS ADAPTED TO BE DISPOSED WITH A RECESS IN A LODAIND PLATFORM; A RAMP HAVING A LOWER SURFACE AND A SUBSTANTIALLY FLAT UPPER FACE; PIVOTAL ATTACHMENT MEANS SECURING ONE END OF SAID RAMP TO SAID FRAME MEANS WHILE LEAVING THE OPPOSITE RAMP END FREE FROM SUCH SECURING; A RAMP ELEVATING MEANS INCLUDING AN ELONGATED BAR DISPOSED IN SUBSTANTIALLY PARALLEL JUXTAPOSITION BENEATH SAID RAMP; SAID ELONGATED BAR HAVING ONE END PIVOTALLY ATTACHED TO SAID FRAME MEANS AND AN OPPOSITE END PIVOTALLY MOUNTING A ROLLER; SAID ROLLER ABUTTING AGAINST SAID RAMP LOWER SURFACE HYDRAULIC CYLINDER AND PISTON MEANS DISPOSED WITHIN SAID FRAME MEANS BENEATH SAID RAMP; SAID HYDRAULIC CYLINDER AND PISTON MEANS HAVING A FIRST END PIVOTALLY ATTACHED TO SAID FRAME MEANS AND A SECOND END THROUGH WHICH A ROD FROM SAID PISTON PROJECTS; MECHANICAL LINKAGE MEANS PIVOTALLY ATTACHED TO SAID PISTON ROD AND TO SAID ELONGATED BAR BETWEEN ITS ENDS; SAID MECHANICAL LINKAGE MEANS INCLUDING A ROCKER ARM AND A LINK, SAID ROCKER ARM BEING CENTRALLY PIVOTED TO SAID FRAME MEANS WITH ONE END THEREOF PIVOTALLY ATTACHED TO SAID PISTON ROD AND WITH THE OTHER THEREOF PIVOTALLY ATTACHED TO THE LOWER END OF SAID LINK, SAID LINK EXTENDING UPWARD AND HAVING ITS UPER END PIVOTALLY ATTACHED TO SAID ELONGATED BAR; SAID MECHANICAL LINKAGE MEANS BEING OPERATIVE, WHEN SAID PISTON ROD IS EXTENDED, TO RAISE SAID ELONGATED ROD AND HENCE TO RAISE SAID RAMP AND BEING OPERATIVE WHEN SAID PISTON ROD IS RETRACTED, TO LOWER SAID ELONGATED ROD AND HENCE TO LOWER SAID RAMP; A LIP PIVOTALLY MOUNTED ADJACENT SAID RAMP FREE END AND NORMALLY HANGING PERPENDICULARLY DOWNWARD FROM SAID RAMP UNDER THE INFLUENCE OF GRAVITY;