Patent ID: 6061874
Filing Date: 2000-05-16
Classification: E05D,E05F,Y10T

Abstract:
A spring loaded piano hinge, comprising:a) a pair of leafs having the same length measured longitudinally thereof, each of the leafs having a plurality of axially aligned and longitudinally spaced hollow knuckles, the hollow knuckles of the leafs being in mating and meshing relation and forming a bore which is coextensive with the leafs, when the leafs are joined together to form the hinge, the joined leafs having a pair of longitudinally spaced opposing ends;b) a rigid hinge pin disposed in the bore at each of the opposing ends of the joined leafs to form a pair of longitudinally spaced hinge pins which have a pair of interiorly spaced confronting ends and about which the joined leafs rotate, the hinge pins having the same outside diameter which is less than the inside diameter of the bore, each of the hinge pins having an enlarged head which is bigger than the bore and disposed exteriorly thereof to restrict axial movement of the hinge pins in the bore in directions towards each other, one of the hinge pins being longer, measured axially, than the other hinge pin which is shorter;c) a coil spring disposed in the bore between the confronting ends of the hinge pins and secured thereto, the coil spring, between the confronting ends of the hinge pins, being hollow and free of any rigid reinforcement within coils of the spring, the coil spring having the same outside diameter as the hinge pins and acting as a continuation of the hinge pins between the confronting ends thereof, the coil spring having a pair of longitudinally spaced opposing ends;d) means for securing the shorter hinge pin to a knuckle of one of the pair of leafs for rotation therewith;e) means for securing the longer hinge pin to a knuckle of the other of the pair of leafs for rotation therewith;f) means for securing the opposing ends of the coil spring to the confronting ends of the hinge pins for rotation therewith, such that the coil spring will act as a torsion spring to resist relative rotation of the leafs, thereby spring loading the hinge; andg) means for removably mounting an enlarged head on at least one of the hinge pins to help in the assembly of the hinge and axially tension the coil spring to maintain the attached hinge pins in the bore.