Abstract: A side knocking-type writing instrument has a barrel having a longitudinal axis, a front end, and a rear end. A sliding member is disposed in the barrel for undergoing forward and rearward sliding movement along the longitudinal axis of the barrel. The sliding member has a shoulder comprised of a generally L-shaped side wall having a first wall portion extending along the longitudinal axis and a second wall portion extending transversely to the longitudinal axis. A knocking member undergoes pivotal movement in a direction transverse to the longitudinal axis of the barrel about a fulcrum point disposed at a rear portion of the knocking member. The knocking member has a pressing portion disposed at a front portion thereof. A linking pawl is disposed between the knocking member and the sliding member for undergoing pivotal movement therebetween and axial movement along the longitudinal axis.

Abstract: An automatic pencil for automatically dispensing a writing lead comprises a hollow, longitudinal main body for receiving therein lead, and a mouthpiece detachably connected at its rear end to a front end of the main body for projecting a top of the lead received in the main body from a front end of the mouthpiece. A slider is movably disposed in a front portion of the mouthpiece for frictionally holding therein the lead, the slider being manually, reciprocally moveable in the axial direction of the pencil in response to writing pressure applied thereto during use of the pencil. A chuck is mounted in a rear portion of the mouthpiece for releasably clamping the lead during use of the pencil such that the chuck operates in response to the reciprocating movement of the slider to allow advancing movement of the lead toward the front end of the mouthpiece and to prevent retracting movement of the lead.

Abstract: Mechanical pencil in which a chuck assembly for gripping a lead is formed with plural chuck elements mutually combined with each other. The chuck assembly has an internal longitudinal hole to insert a lead through and a lead gripping portion to grip the lead, while a lead guide tube is movably inserted within the lead inserting hole. The lead guide tube pushes on acting portions of the chuck to open the gripping portions of the chuck elements in the direction of parting them from each other when the lead guide tube is advanced, and the lead gripping portion opens to release the lead. The chuck is designed to enable releasing and gripping the lead securely so that it can be suitably used as a chuck mechanism for extending the lead automatically.

Abstract: A mechanical pencil having a chuck mechanism which permits the lead to advance but prevents the lead from retracting, a first slider, a second slider which is retractable progressively as a writing pressure is applied, a first engagement device for holding the second slider at its retracted position and a second engagement device for holding the first slider at its retracted position. The progressively retracted second slider is released to advance to the forward original position by applying a further writing pressure to cause a retraction of the first slider. Then, the second slider is advanced forwardly together with the lead so that the lead is advanced to a writing position.

Abstract: A mechanical pencil includes a lead engaging collet biased rearwardly, a collet receiver tube having a tapered guide face and rolling elements mounted between the tapered guide face and the collet for inducing a clamping force against a writing lead. The pencil includes a device for advancing the collet receiver tube and the collet toward a pencil tip and then permitting the collet receiver tube alone to move rearwardly. This assures that the inner elements will step the lead an increment from the pencil tip for writing purposes.

Abstract: A mechanical pencil includes a casing, a chuck for holding a lead, a lead passage connected with the chuck, a lead cartridge and a push button for advancing the lead. A cylindrical body is connected to the lead passage. The cylindrical body and the lead cartridge have guides so that the both may be snuggly and accurately engaged with each other in accordance with the diameter of leads which are used in the pencil.