Self-opening bin lid

Claim 1

A LID ASSEMBLY FOR AN OPEN-TOP BIN LOADED WITH FLOWABLE MATERIAL, THERE BEING MEANS TO SUPPORT THE BIN FOR ROTATION IN ONE DIRECTION ABOUT A HORIZONTAL AXIS; SAID LID ASSEMBLY INCLUDING A BIN-ENGAGING FRAME, AN INITIALLY CLOSED LID EXTENDING LATERALLY INWARDLY FROM THE UPPER SIDE EDGE OF THE BIN WHICH LEADS UPON ROTATION THEREOF IN SAID DIRECTION, MEANS PIVOTING THE LID ON THE FRAME LATERALLY INWARDLY FROM SAID BIN EDGE FOR SWINGING ABOUT AN AXIS PARALLEL TO THE AXIS OF ROTATION OF THE BIN AND RELATIVE OUTWARD OPENING MOVEMENT, AND MEANS WEIGHTING THE LID IN A POSITION RELATIVE TO THE PIVOT MEANS SO THAT THE LID REMAINS CLOSED AGAINST THE PRESSURE OF THE LOAD UNTIL THE BIN IS ROTATED TO A POINT WHEREIN THE LID IS SUSPENDED FROM ITS AXIS; THE LID REMAINING SO SUSPENDED, PROGRESSIVELY RELATIVELY OPENING, AND CONTROLLING THE GRAVITATIONAL FLOW OF MATERIAL FROM THE BIN UPON CONTINUED ROTATION THEREOF FROM SUCH POINT TOWARD AN INVERTED POSITION; SAID LID WEIGHTING MEANS COMPRISING A COUNTERWEIGHT DISPOSED IN SPACED RELATION OUTWARDLY OF THE LID, AND A RIGID ARM STRUCTURE MOUNTING THE COUNTERWEIGHT IN UNITARY CONNECTION WITH THE LID.