A thermochromic writing instrument including a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit, for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit 10 is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

The writing instrument comprises a first barrel, a second barrel, and a self-blocking assembly system for assembling the first barrel with the second barrel. The self-blocking assembly system includes a blocking device for blocking the first barrel with respect to the second barrel in a longitudinal direction and a locking device for locking the blocking device. The locking device includes a slot formed in the first barrel and two ramps carried by the second barrel. The slot extends in the longitudinal direction and has two longitudinal edges. The two ramps are configured to part the two longitudinal edges of the slot progressively in a circumferential direction as the first and second barrels are assembled. A window extends in the longitudinal direction formed between the two ramps, and a lateral button is housed at least partially in the window that includes guide surfaces for guiding the lateral button.

A retractable writing instrument includes a push member including a clip and a protruding and retracting mechanism that causes a pen point to protrude from and retract into a front end of the barrel at a frontward press on the push member, without the push member rotating with respect to the instrument. The protruding and retracting mechanism includes cam teeth and cam grooves formed in an inner face of the barrel, a rotary member including protuberances engageable alternately with the cam teeth or the cam grooves, a cam member connected to the push member and includes cam projections rotating the rotary member, and engagement projections engaged with the cam grooves in the inner face of the barrel so as to be movable in the longitudinal direction; and a resilient element that biases the writing element rearward. The push member and the cam member are in detent engagement with each other.

A clip body includes one upper wall extending in a longitudinal direction of a barrel and a pair of side walls formed at least on a front side of the upper wall, projecting from both side portions of the upper wall in a direction of a surface of the barrel, and having inner surfaces facing each other, a holding portion is provided on a back side of the clip body and between the pair of side walls, has a shape capable of producing an elastic force by deformation, and projects more in the direction of the surface of the barrel than the pair of side walls, the surface of the barrel includes a guide groove extending in the longitudinal direction of the barrel and provided with a bottom surface contacting the holding portion and a pair of side surfaces to restrict lateral movement of the holding portion, and a clip base is connected to a rear side of the clip body and supports the clip body at a height not to cause the pair of side walls to contact the surface of the barrel and the holding portion to contact the bottom surface of the guide groove.

The present invention includes: a shaft cylinder having an opening at a front end thereof, a tip holder movable in an axial direction of the shaft cylinder, a tip projectable and retractable in conjunction with a movement of the tip holder, an annular member loosely fitted onto an inner periphery of the opening of the shaft cylinder to be movable in an axial direction of the shaft cylinder with respect to the shaft cylinder, and an elastic member capable of connecting the tip holder and the annular member such that the tip holder and the annular member are movable relatively to each other. A contact surface tapered toward the front end is formed on at least a part of an outer periphery of the annular member. A cutout is formed at a part of the annular member such that an inner diameter of the annular member is reduced when a load is received by the contact surface. A guide surface tapered toward the front end is formed on the part of the inside surface of the shaft cylinder. The contact surface is configured to receive the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.

A thermochromic writing instrument including a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit, for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit 10 is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

The writing instrument comprises a first barrel, a second barrel, and a self-blocking assembly system for assembling the first barrel with the second barrel. The self-blocking assembly system includes a blocking device for blocking the first barrel with respect to the second barrel in a longitudinal direction and a locking device for locking the blocking device. The locking device includes a slot formed in the first barrel and two ramps carried by the second barrel. The slot extends in the longitudinal direction and has two longitudinal edges. The two ramps are configured to part the two longitudinal edges of the slot progressively in a circumferential direction as the first and second barrels are assembled. A window extends in the longitudinal direction formed between the two ramps, and a lateral button is housed at least partially in the window that includes guide surfaces for guiding the lateral button.

A pen for writing and/or drawing purposes, and having a shaft and a core which is arranged within the shaft and is axially adjustable in the longitudinal direction of the shaft between an active position and an inoperative position. The core is completely arranged within the shaft in the inoperative position and projects with an overhang from a front end of the shaft in the active position. An actuating element is provided which is movable perpendicularly to the longitudinal direction of the shaft between an active position and an inoperative position and which is operatively connected to the core via a connecting element in such a way that, during a movement of the actuating element perpendicularly to the longitudinal direction of the shaft between the inoperative position and the active position, the core is axially adjustable in the longitudinal direction of the shaft.

A writing instrument having an automatic sealing structure, in which a hinge part of a holder has projection jaws formed thereon having a role of a stopper that can prevent a hinge shaft from being excessively pivoted, thereby more effectively preventing ink from drying out due to complete sealing of the nib. The writing instrument having an automatic sealing structure, including: a body case having a front opening formed in one end thereof; a knock part coupled to the other end of the body case so as to make a nib protrude from or be retracted into the front opening of the body case by a pushing operation thereof; a cartridge inserted into the body case together with a spring in a state in which the knock part and the nib are coupled to both ends thereof, respectively; at least one O-ring fixedly fitted in the body case; a holder fixedly fitted in the body case so that one end thereof is covered by the O-ring; and a ball shutter pivotally coupled to the holder to allow the nib to protrude or be sealed according to the pivoting thereof, wherein the ball shutter includes hinge shafts formed in a fan shape, and hinge parts of the holder, in which the hinge shaft is pivotally positioned, have projection jaws formed thereon by protruding inwardly to limit a pivot range of the hinge shaft.

A retractable writing instrument includes a push member including a clip and a protruding and retracting mechanism that causes a pen point to protrude from and retract into a front end of the barrel at a frontward press on the push member, without the push member rotating with respect to the instrument. The protruding and retracting mechanism includes cam teeth and cam grooves formed in an inner face of the barrel, a rotary member including protuberances engageable alternately with the cam teeth or the cam grooves, a cam member connected to the push member and includes cam projections rotating the rotary member, and engagement projections engaged with the cam grooves in the inner face of the barrel so as to be movable in the longitudinal direction; and a resilient element that biases the writing element rearward. The push member and the cam member are in detent engagement with each other.