Writing instrument

A writing instrument, comprising:

• a writing body stored in a barrel;
• an operation body provided at the barrel to be operated to longitudinally move the writing body;
• and a nib of the writing body configured to be capable of appearing from a front end of a writing instrument, wherein
• the writing instrument further includes a longitudinally extending slide hole provided in a side wall of the barrel, and an appearance mechanism putting the nib of the writing body from a retraction condition into a projection condition by slide operating the operation body placed in the slide hole forward,
• the barrel includes therein, as the appearance mechanism, a first set of cam teeth, and cam grooves both longitudinally extending and alternately placed along a circumferential direction, a rotary member having a plurality of projected ribs rotatably placed in the rear of the writing body and capable of alternately engaging with the first set of cam teeth or the cam grooves, a second set of cam teeth provided in the operation body and turning the rotary member, and an biasing member biasing the writing body backward,
• the operation body is provided with a longitudinally extending stem stored in the barrel, a longitudinally extending rib is formed on an outer surface of a base portion of the operation body or on an outer surface of the stem and a longitudinally extending groove is formed on an inner surface of the barrel and the rib is engaged with the groove and moves along the groove longitudinally, and
• by slide operating the operation body forward against a biasing force of the biasing member, the projected ribs are alternately engaged with the first set of cam teeth or the cam grooves at longitudinally different positions to alternately put the nib of the writing body in the projection condition or the retraction condition.

A thermochromic writing instrument, comprising:

• a writing body storing a thermochromic ink therein, stored in a barrel;
• an operation body provided at 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 further includes a friction unit, rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time,
• the barrel includes a front barrel, an intermediate barrel coupled to a rear end of the front barrel, and a rear barrel coupled to a rear end of the intermediate barrel, a longitudinally extending slide hole is provided in a side wall of the intermediate barrel, the operation body is placed in the slide hole and the friction unit is provided at a rear end of the rear barrel independently of the operation body, and the front barrel and the intermediate barrel are detachably coupled by screwing, and thus the writing body can be replaceable, and
• an outward projection is formed on an outer surface of the intermediate barrel, an inward projection is formed on an inner surface of the rear barrel, and the outward projection on the outer surface of the intermediate barrel and the inward projection on the inner surface of the rear barrel climb over and are engaged with each other.

A thermochromic writing instrument, comprising:

• a writing body storing a thermochromic ink therein, stored in a barrel;
• an operation body provided at 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 further includes a friction unit, rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time,
• the barrel includes a front barrel, an intermediate barrel coupled to a rear end of the front barrel, and a rear barrel coupled to a rear end of the intermediate barrel, a longitudinally extending slide hole is provided in a side wall of the rear barrel, the operation body is placed in the slide hole and the friction unit is provided at a rear end of the rear barrel independently of the operation body, and the front barrel and the intermediate barrel are detachably coupled by screwing, and thus the writing body can be replaceable, and
• an outward projection is formed on an outer surface of the intermediate barrel, an inward projection is formed on an inner surface of the rear barrel, and the outward projection on the outer surface of the intermediate barrel and the inward projection on the inner surface of the rear barrel climb over and are engaged with each other.

A thermochromic writing instrument, comprising:

• a writing body storing a thermochromic ink therein, stored in a barrel;
• an operation body provided at 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 further includes a friction unit made from a low wear elastic material for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time at a rear end of the barrel and
• a longitudinally extending slide hole provided in a side wall of the barrel, and an appearance mechanism putting the nib of the writing body from a retraction condition into a projection condition by slide operating the operation body placed in the slide hole forward,
• the barrel includes therein, as the appearance mechanism, a first set of cam teeth, and cam grooves both longitudinally extendin and alternately placed along a circumferential direction, a rotary member having a plurality of projected ribs rotatably placed in the rear of the writing body and capable of alternately engaging with the first cam teeth or the cam grooves, a second set of cam teeth provided in the operation body and turning the rotary member, and an biasing member biasing the writing body backward,
• by slide operating the operation body forward against a biasing force of the biasing member, the projected ribs are alternately engaged with the first set of cam teeth or the cam grooves at longitudinally different positions to alternately put the nib of the writing body in the projection condition or the retraction condition,
• the barrel includes a plurality of components, of which component having the slide hole is provided with the first set of cam teeth and the cam grooves on an inner surface of the side wall and a guide groove is provided, which guide groove longitudinally extends forward of the slide hole of an outer surface of the side wall, and
• the operation body is a clip body and a projected bump is provided on a front inner surface of the clip body, and the bump longitudinally slides in the guide groove in association with a longitudinal movement of the clip body.