Convertible writing instrument assemblies are provided, including an outer barrel having a tapered nosecone with an aperture for a writing instrument tip and a grip portion, and an aperture for receiving an eraser or a push button therethrough, wherein the writing instrument assembly provides selective access to a volume defined by the outer barrel, and wherein the outer barrel and the volume are collectively configured to operably and interchangeably receive a mechanical pencil insert having the eraser and a retractable pen insert having the push button. Mechanical pencils and pens utilizing the convertible writing instrument assemblies are also provided, along with kits for providing such mechanical pencils and pens.

Convertible writing instrument assemblies are provided, including an outer barrel having a tapered nosecone with an aperture for a writing instrument tip and a grip portion, and an aperture for receiving an eraser or a push button therethrough, wherein the writing instrument assembly provides selective access to a volume defined by the outer barrel, and wherein the outer barrel and the volume are collectively configured to operably and interchangeably receive a mechanical pencil insert having the eraser and a retractable pen insert having the push button. Mechanical pencils and pens utilizing the convertible writing instrument assemblies are also provided, along with kits for providing such mechanical pencils and pens.

A mechanical pencil is including a tubular shaft, a chuck unit movably arranged in the shaft, a front rotary element adapted to be moved rearward as the unit is moved rearward, a rear rotary element adapted to be moved rearward as the front rotary element is moved rearward, a conversion means for causing the rear rotary element to rotate in a normal rotational direction as the rear rotary element is moved rearward and allowing the rear rotary element to rotate in a reverse rotational direction as the rear rotary element is moved forward, a normal directional rotation transmitting means for allowing the front rotary element to be rotated in the normal rotational direction and the rear rotary element to be idly rotated, and a reverse directional rotation restricting mechanism allowing the normal directional rotation of the front rotary element but preventing the reverse directional rotation of the front rotary element.

A mechanical pencil is including a tubular shaft, a chuck unit movably arranged in the shaft, a front rotary element adapted to be moved rearward as the unit is moved rearward, a rear rotary element adapted to be moved rearward as the front rotary element is moved rearward, a conversion means for causing the rear rotary element to rotate in a normal rotational direction as the rear rotary element is moved rearward and allowing the rear rotary element to rotate in a reverse rotational direction as the rear rotary element is moved forward, a normal directional rotation transmitting means for allowing the front rotary element to be rotated in the normal rotational direction and the rear rotary element to be idly rotated, and a reverse directional rotation restricting mechanism allowing the normal directional rotation of the front rotary element but preventing the reverse directional rotation of the front rotary element.

Convertible writing instrument assemblies are provided, including an outer barrel having a tapered nosecone with an aperture for a writing instrument tip and a grip portion, and an aperture for receiving an eraser or a push button therethrough, wherein the writing instrument assembly provides selective access to a volume defined by the outer barrel, and wherein the outer barrel and the volume are collectively configured to operably and interchangeably receive a mechanical pencil insert having the eraser and a retractable pen insert having the push button. Mechanical pencils and pens utilizing the convertible writing instrument assemblies are also provided, along with kits for providing such mechanical pencils and pens.

Convertible writing instrument assemblies are provided, including an outer barrel having a tapered nosecone with an aperture for a writing instrument tip and a grip portion, and an aperture for receiving an eraser or a push button therethrough, wherein the writing instrument assembly provides selective access to a volume defined by the outer barrel, and wherein the outer barrel and the volume are collectively configured to operably and interchangeably receive a mechanical pencil insert having the eraser and a retractable pen insert having the push button. Mechanical pencils and pens utilizing the convertible writing instrument assemblies are also provided, along with kits for providing such mechanical pencils and pens.

A side-knock type mechanical pencil comprising a body with a side-mounted knock button coupled to the body of the mechanical pencil and adapted to slidingly engage with a lead tube with a frustoconical hub for translating the motion of the knock button actuation to linear extension of the lead.

A side-knock type mechanical pencil comprising a body with a side-mounted knock button coupled to the body of the mechanical pencil and adapted to slidingly engage with a lead tube with a frustoconical hub for translating the motion of the knock button actuation to linear extension of the lead.

A mechanical pencil includes a barrel extending in a longitudinal direction, a lead-propelling mechanism, a lead reservoir, a side button, and an eraser-propelling mechanism having a helical cam. The lead-propelling mechanism, the lead reservoir, the eraser-propelling mechanism, and the side button are at least partly housed inside the barrel. The lead-propelling mechanism, the lead reservoir, and the eraser-propelling mechanism are prevented from rotating about the longitudinal direction relative to one another and relative to the side button, and the side button is prevented from rotating about the longitudinal direction relative to the barrel.

A mechanical pencil includes a barrel extending in a longitudinal direction, a lead-propelling mechanism, a lead reservoir, a side button, and an eraser-propelling mechanism having a helical cam. The lead-propelling mechanism, the lead reservoir, the eraser-propelling mechanism, and the side button are at least partly housed inside the barrel. The lead-propelling mechanism, the lead reservoir, and the eraser-propelling mechanism are prevented from rotating about the longitudinal direction relative to one another and relative to the side button, and the side button is prevented from rotating about the longitudinal direction relative to the barrel.