Abstract: An anti-rotation mechanism for a retractable eraser or other stick-like object for use with a writing instrument that utilizes locking elements to prevent the inadvertent retraction or extension of the eraser when pressure is applied to the eraser during the erasing operation.

Abstract: An eraser assembly having at least one eraser, an eraser holder having a first rim including at least one notch, the eraser being disposed in the eraser holder and an eraser cap having at least one tab extending therefrom. The tab of the eraser cap engages the notch of the eraser holder, thereby securing the cap to the eraser holder and enclosing the eraser.

Abstract: An eraser assembly having at least one eraser, an eraser holder having a first rim including at least one notch, the eraser being disposed in the eraser holder and an eraser cap having at least one tab extending therefrom. The tab of the eraser cap engages the notch of the eraser holder, thereby securing the cap to the eraser holder and enclosing the eraser.

Abstract: An eraser advancing mechanism for a mechanical pencil has a pair of nested screws within a barrel. A second screw, with outwardly directed threads, extends through a conduit in a first screw that includes outwardly directed threads and a thread in the conduit meshing with the threads of the second screw. An eraser ferrule includes a thread that meshes with the outwardly directed threads of the first screw. The ferrule includes a knob serving to drive rotation of the eraser ferrule, and hence the first screw. The first screw includes a head with a profile that complements the inner profile of the barrel. Rotation of the first screw causes rotation of the barrel and serves to create a counter-rotation of the second screw, leading to axial movement of the second screw relative to the first screw.

Abstract: An eraser for a ring binder comprising an eraser element having at least one hole extending therethrough. The hole is sized so as to provide access to a ring of a ring binder. The eraser preferably has a triangle-like shape comprising a base, a first side, and a second side. The base is preferably curved so as to accommodate a notebook organizer of the type having an organizer base with a substantially flat bottom surface and with a plurality of holes being adapted for engagement with the rings of a ring notebook.

Abstract: An eraser consisting of a body having an aperture. A cloth covering is mounted to a portion of the body. When a writing instrument is inserted in the aperture the writing instrument provides a handle by which the body may be manipulated.

Abstract: Blackboard rubber made of metal or having a metal base made up of two parts enclosed one within the other, the first part being in the form of a rectangular box and the second part being flat and forming a lid to the first part; the said second part comprises a centered metal plate and a magnet and is covered with a detachable rubbing sheet of soft material.