Rotary shelf assembly mechanism

Claim 1

ROTARY SHELF ASSEMBLY COMPRISING, IN COMBINATION: (A) A VERTICAL SHAFT MOUNTED FOR ROTATION ABOUT ITS CENTRAL AXIS, (B) AT LEAST ONE SUBSTANTIALLY CIRCULAR SHELF MOUNTED ON SAID SHAFT, (C) A CAM MOUNTED ON SAID SHAFT SUBSTANTIALLY PARALLEL TO SAID SHELF, (D) SAID CAM HAVING A SHALLOW CIRCULAR PERIPHERAL NOTCH AND HAVING A GRADUAL RISE PORTION DISPOSED ON EACH SIDE OF SAID CAM, (E) SAID CAM HAVING A REST PORTION CONNECTING THE HIGHER POINTS OF SAID RISE PORTIONS AND MERGING THEREWITH, (F) A FOLLOWER ROLLER FOR SAID CAM, (G) A LEAF SPRING DISPOSED SUBSTANTIALLY IN THE PLANE OF THE CAM AND ARCHED TO FOLLOW GENERALLY THE PERIPHERY OF THE CAM, (H) MEANS FOR ROTATABLY MOUNTING SAID ROLLER ON ONE END OF SAID SPRING WITH ITS AXIS SUBSTANTIALLY PARALLEL TO THAT OF THE SHAFT, (I) A HOLDER FOR THE OTHER END OF SAID SPRING, (J) MEANS MOUNTING SAID HOLDER FOR ADJUSTMENT IN A SUBSTANTIALLY RADIAL PATH TOWARD AND AWAY FROM SAID CAM, (K) SAID HOLDER HAVING MEANS DEFINING A PASSAGEWAY THROUGH WHICH THE OTHER END OF THE SPRING IS PASSED, SAID PASSAGEWAY BEING SUBSTANTIALLY PERPENDICULAR TO SAID RADIAL PATH, (L) SAID HOLDER HAVING MEANS FOR SECURING SAID SPRING IN THE PASSAGEWAY, WHEREBY (M) THE ADJUSTMENT OF SAID HOLDER RADIALLY TOWARD AND AWAY FROM SAID CAM AND THE ADJUSTMENT OF THE SPRING IN THE PASSAGEWAY SERVING JOINTLY TO REGULATE THE PRESSURE OF SAID FOLLOWER ROLLER AGAINST THE CAM NOTCH TO PROVIDE A FIRM STOP AND TO EQUALIZE THE PRESSURE ON THE TWO RISE PORTIONS OF THE CAM SO THAT THE CAM WILL ROTATE WITH EQUAL EASE IN EITHER DIRECTION.