Abstract: A self-returning hinge assembly utilizing a spring disposed along a linearly displaceable guide shaft element mounted through a polymeric guide plate disposed in substantial alignment with an aperture supporting an elongated proximal portion of the guide shaft. Upon displacement of the door from a pre-established set point, the spring is compressed thereby generating a biasing force along the guide shaft to bring the door back to the pre-established set point. The linear travel path of the guide shaft element is maintained by the guide plate.

Abstract: A multi-user mail box including a letter drop assembly which is susceptible to easy replacement by a delivery person without requiring substantial disassembly of the mail box. The letter drop assembly includes a slotted body held in inserted relation between cross-bars extending transverse to vertical frame members of an access door structure. The slotted body includes upper and lower open grooves oriented in opposing relation to the adjacent cross-bars. Retention pin elements are inserted axially into the grooves thereby holding the slotted body in place. The slotted body may be replaced by displacement of the retention pin elements.

Abstract: A mail receptacle system incorporating multiple individually accessible discrete storage compartments disposed within a frame structure with lockable user access doors disposed in mated hinging relation relative to the frame structure such that when the access doors are in a closed position, a male/female relation is established between portions of the doors and the frame structure. The access doors utilize a multi-piece construction wherein the hinging edges of the doors are displaceable from the door body thereby permitting the door body to be easily and readily replace in the event of damage.

Abstract: A spring biased pivot assembly for operative connection across a lower edge of a self-returning door structure. An adjustable spacer projects outwardly from a downwardly extending shoulder structure and towards a tension pin in tangential relation to the axis of rotation. The spacer contacts the tension pin when the door structure is in its normal position thereby maintaining separation between the tension pin and the shoulder structure and blocking complete release of spring tension.

Abstract: Gravity hinge assembly which does not rely upon an axial rod or pintle to maintain axial alignment between the cam cylinders. The assembly incorporates an inter-connective attachment arrangement between the upper rotating cam cylinder and the door connection plate to form a simplified operative connection between the door and the upper cam cylinder while maintaining axial stability.

Abstract: A spring hinge including a pair of hinge leaves having hollow knuckles on adjacent hinges which are arranged in substantially axial alignment such that the hollow knuckles comprise segments of a hinge barrel. A torsion spring made up of a resilient coiled spring member is housed within the hinge barrel. First and second pintles are disposed at opposing ends of the hinge barrel and extend into and between axially aligned knuckles of the hinge leaves. The first and second pintles each engaging the spring member in a locked arrangement such that the spring member extends in a substantially locked relation between the first and second pintles.

Abstract: An spring hinge construction comprising a pair of hinge leaves having hollow knuckle portions axially aligned to form a hinge barrel containing a torsion spring. A pintle in each end of the barrel operatively engages an adjacent end of the spring to fix it against relative rotation. One pintle is fixed, through a leaf knuckle, to one hinge leaf, and the other pintle is rotationally adjustable to set a desired torsion on the spring, after which it is fixed against counter-rotation by means of a loose pin which is inserted through an elongate slot in a knuckle of the other leaf and into a selected radial passageway opening in the pintle which aligns with the end of the slot.