Abstract: A loose-leaf binder is disclosed having a pair of separable cover members with rib portions and a centrally disposed fastening sleeve assembly disposed for insertion through a central aperture in the rib. An outer sleeve of said fastening sleeve assembly is tapered at one of its extremities to coact with ball locks carried by an inner sleeve member which is slidably disposed for limited longitudinal movement within said outer sleeve, and which is hollow at one of its extremities to receive the locking pin. The operating extremity of the inner sleeve member is provided with a transverse aperture which passes diametrically therethrough to receive an operating member in the form of a ring which is sized so that it will not interfere with closing of the cover no matter what the rotative position of the ring when disposed in the inoperative position which is flat, parallel to and in contact with the rib of the closed binder.

Abstract: A binder mechanism having two longitudinal bars on which the page holding prongs are mounted. The bars are interconnected by two rectangular movable hinge members situated proximate opposite ends of the bars. The hinge members which have two right angle sections interconnected by a piano hinge are rotatably connected to the bars and define a rectangular box-shaped structure with the bars when the binder is in the locked position. Both hinge members and bars have a thin rectangular cross-section, the long dimension of which is vertically oriented when the hinge members and the bars are in the locked position. The hinge members pivot about pins which interconnect the hinge members to the bars to rotate to an open position with the piano hinge rotated 90.degree.. One hinge member then rotates about the piano hinge to open the binder so that the longitudinal bars are in a horizontal position and the prongs are vertically disposed. In this position, pages can be removed and inserted.