FR3076254A1 - RECHARGEABLE WRITING INSTRUMENT - Google Patents

Abstract

Rechargeable writing instrument (10) comprising a body (12) having at least one lateral opening (12b1), at least one writing element (14a, 14b, 14c, 14d) comprising a writing tip (17, 18 ) and a button (13), the button extending through the opening (12b1) and for moving the writing element between a retracted position and a writing position, the button being free of movement towards the outside of the body in the radial direction (R) within the opening whereby the writing element is removable, and a locking member (16) movable between a locking position and a replacement position, in the locking position the locking element cooperating with the button so as to radially block the button towards the outside of the body at least when the writing element is in the retracted position, while in the replacement position the element lock releases the button radially.

Description

FIELD OF THE INVENTION The invention relates to a rechargeable writing instrument, and in particular, but not only, a rechargeable multifunction writing instrument. As a reminder, a multifunction writing instrument 5 is a writing instrument comprising a plurality of writing elements, each writing element being able to be used selectively.

STATE OF THE PRIOR ART [0002] The structures of known writing instruments, in particular multifunction writing instruments, do not always allow easy replacement of the writing element or elements. There is therefore a need in this sense.

PRESENTATION OF THE INVENTION One embodiment relates to a rechargeable writing instrument comprising a body extending in an axial direction and a radial direction and having at least one lateral opening, at least one writing element disposed at inside the body and comprising a writing tip and a button, the button extending radially through the opening and allowing the writing element to be moved between a retracted position in which the writing tip is retracted into the body, and a writing position in which the writing point protrudes from the body, the button being free to move outward from the body in the radial direction within the opening whereby the writing element is removable from the body, and a blocking element movable between a blocking position and a replacement position, in the blocking position the blocking element cooperating with the button so as to radially block the button towards the outside of the body at least when the writing element is in the retracted position, while in the replacement position the blocking element releases the button radially towards the outside of the body, thanks to what the writing element can be removed from the body.

In general, the axial direction corresponds to the direction of the body tax, and a radial direction is a direction perpendicular to the axis of the body.

Of course, the writing instrument can have a single writing element, or a plurality of writing elements and thus form a multifunction writing instrument. Thereafter, and unless otherwise indicated, by "the writing element" means "the at least one writing element".

Within the meaning of the present invention, a writing element is formed by any assembly comprising a writing tip and a button. The writing tip can for example be a felt tip, a ball point or the like, a graphite lead, a mechanical pencil mechanism, a chalk and more generally any means allowing writing on a substrate or any configured tip (active or passive) to cooperate with a touch screen, for example a capacitive, resistive, inductive, infrared, optical, electrostatic screen, etc.

It is understood of course that the body can be formed in one and the same piece, or include several separate pieces. Within the meaning of the present invention, the body comprises all the parts other than the writing element or elements and the blocking body. The body is of course hollow and configured to receive the writing element. The body thus has an interior and an exterior. The lateral opening is a through opening formed in a wall of the body and opening radially. The body is provided with at least one opening per writing element. Thus, the button of each writing element is received in a separate opening. In other words, there are at least as many openings as there are writing elements.

We also understand that a retraction mechanism of any type and known elsewhere allows to move, thanks to the button, the writing element between the retracted position and the writing position, and maintain the writing element in each of these positions. Of course, there are as many retraction mechanisms as there are writing elements, each mechanism being specific to a writing element. In other words, each writing element is provided with such a retraction mechanism.

The button is guided in the opening for the passage of the writing element from the writing position to the retracted position and vice versa. For example, the opening is of substantially rectangular shape, the long sides of the rectangular shape extending in the axial direction. In such an example, the button is guided axially by the long sides of the opening. The short sides can limit the axial travel of the button, but not necessarily.

The button, however, remains free relative to the opening in the radial direction, at least towards the outside of the body. Thanks to this radial freedom towards the outside of the body, it is possible to extract the button from the opening, and consequently to remove the writing element from the body. This replaces the writing element.

However, to ensure that the writing element does not unintentionally disengage from the opening, and consequently that the writing element is inadvertently ejected from the body, the writing instrument has a blocking element. This blocking element makes it possible to radially block the button within the opening when it is in the blocking position. It is understood that in the blocking position, the blocking element cooperates with the button so as to block it radially outward, either permanently, that is to say whatever the position of the element. writing, or only when the writing element is in the retracted position. The retracted position is the position where the writing element has the greatest risk of being disengaged from the opening. Indeed, in the writing position, the writing element is more strongly engaged with the body so that the risk of disengagement is less, or even non-existent.

Of course, in the replacement position, the blocking element does not operate any radial blocking towards the outside of the button, whereby the replacement of the writing element is possible.

In summary, the button is radially movable within the opening, whereby the writing element can be removed from the body for replacement while the blocking element allows the button to be blocked radially, at less when the writing element is in the retracted position, that is to say the position presenting the greatest risk of being involuntarily disengaged from the body. When it is desired to replace the writing element, the locking element is put in the replacement position, whereby the button can be removed radially from the opening and the assembly of the writing element removed to its replacement. Such a writing instrument structure is easy to use and reliable, while having a reduced number of parts facilitating its manufacture.

In some embodiments, the blocking element is movable relative to the body, a lock making it possible to reversibly lock the blocking element in the blocking position relative to the body.

In other words, when the lock is in the locked position, the blocking element is blocked in the blocking position, while in the unlocked position the bolt allows the blocking element to come in the position of replacement. The lock can be integrated into the body and / or the blocking element, or comprise a separate part, this part being independent of the body and the blocking element and being able to be mounted on the body or the blocking element, or not. For example, the locking system is a reversible screw, bayonet, snap (i.e. clipping) system, or any other reversible coupling system known elsewhere.

For example, the blocking element is movable in the axial direction relative to the body between the blocking position and the replacement position, the displacement of the blocking element in a first axial direction bringing the element blocking of the blocking position towards the replacement position while the displacement of the blocking element in the second axial direction, opposite to the first axial direction, bringing the blocking element from the replacement position towards the blocking position. When the lock is in the locked position, the movement of the blocking element in the first axial direction is blocked while in the unlocked position such movement is allowed. In the locked position, the lock can block all movements of the blocking element relative to the body, or else blocks only the movement to return to the replacement position.

Such a lock makes it possible to ensure that the blocking element remains in the blocking position and properly blocks the button radially in the opening, and this in an easily reversible manner. This avoids any untimely disengagement of the writing element from the body, which makes the writing instrument more reliable while allowing easy replacement of the writing element.

In some embodiments, the latch is mounted to play on the locking element or on the body.

It is understood that the lock is a separate part of the locking element and the body. The lock is mounted on the blocking element or on the body but retains a certain degree of freedom thanks to the play. For example, if the locking system is a threaded system, the lock is a nut. In such an example, the nut is free to rotate relative to the locking element and the body, to allow it to be screwed, and may also have a certain freedom of movement in the axial direction, but not necessarily.

Such a structure allows to form a reliable locking system and easy to manufacture. Furthermore, the lock being mounted on the movable element or on the body, it cannot be lost, which has a definite advantage for long-term use of the writing instrument, thanks to which the possibility of d '' thus avoid any untimely disengagement of the writing element of the body during its life.

In some embodiments, in the blocking position of the blocking element, the lock cooperates in abutment with the blocking element so as to block the movement of the blocking element to go to the replacement position.

It is therefore understood that only the movement to move the locking element to the replacement position is blocked by the latch. Thus, the blocking member may be free to move in another direction, but not necessarily.

Such a structure is simple and allows efficient and reliable locking, and this in an easily reversible manner. This avoids any untimely disengagement of the writing element from the body, which makes the writing instrument more reliable while allowing easy replacement of the writing element.

In some embodiments, the blocking element comprises an abutment portion configured to cooperate radially in abutment with the button.

For example, the stopper portion is formed by an axially movable tongue which seals a portion of the opening in the locked position and which disappears in the replacement position.

Such a structure is simple and allows efficient and reliable blocking, and this in an easily reversible manner. This avoids any untimely disengagement of the writing element from the body, which makes the writing instrument more reliable while allowing easy replacement of the writing element.

In some embodiments, the stop portion is configured to also cooperate axially in abutment with the button.

Such a configuration allows, when the writing instrument comprises a mechanical pencil, the portion forming an abutment to cooperate with the corresponding button to advance the lead of the mechanical pencil, while guaranteeing the radial maintenance of the others buttons.

In some embodiments, the opening has an edge configured to cooperate with the button and guide the button radially outward from the body when the locking element is in the replacement position.

For example, such an edge has an inclined face forming a ramp. Thus, by sliding the button in the axial direction on this ramp, the edge of the opening guides the button radially outwards, which makes it easier to remove the writing element.

Such a structure is simple and facilitates the removal and introduction of the writing element into the body. The replacement of the writing element is thus facilitated.

In some embodiments, the writing element is a mechanical pencil system comprising a mechanical mechanism and a mine reservoir, the blocking element in the blocking position being axially movable at least when the element d The writing is in the writing position so as to be able to advance a mine from the writing point.

Of course, if the writing instrument comprises several writing elements, at least one of these writing elements is a mechanical pencil system. According to a variant, a single writing element is a mechanical pencil system. According to another variant, several writing elements are mechanical pencil systems. According to yet another variant, all the writing elements are mechanical pencil systems.

It is understood that the mechanical pencil mechanism is a mechanism known elsewhere, for example pliers, which allows to block a mine in position and to advance it. In other words, when a writing element is a mechanical pencil system, it includes a mechanical pencil mechanism, a mine tank and a button.

It is also understood that the blocking element makes it possible to move the writing element whatever its position (i.e. in the retracted position and in the writing position) or else only in the writing position. Indeed, when the writing element is in the retracted position, it is not necessary to be able to advance a mine within the mechanical pencil system.

It is therefore understood that when the blocking element is in the blocking position and the writing element is in the writing position, the blocking element remains movable in the axial direction so as to be able to actuate the mine mechanism while remaining locked in the locked position. For example, the blocking element is blocked by a latch in a first axial direction, so as to be prevented from going towards the replacement position, but remains free, from axial displacement in a second axial direction, opposite to the first direction axial, to move beyond the locking position.

The structure of the writing instrument is particularly well suited for a mechanical pencil system, and provides a certain reliability while allowing the reservoir of the mechanical pencil system to be easily recharged.

In certain embodiments, the writing instrument comprises a plurality of writing elements and a single blocking element configured to block radially, in the blocking position, at least all of the writing elements which are in the retracted position.

It is therefore understood that the blocking element is unique. This provides great ease of use of the writing instrument. Indeed, a single manipulation is enough to pass the blocking element from the blocking position to the replacement position, and thus facilitates the replacement of all the writing elements. This also gives greater reliability to the writing instrument: in a single manipulation, it is ensured that all the writing elements are blocked radially by the blocking element, whereby it is ensured that no writing element can be inadvertently disengaged.

BRIEF DESCRIPTION OF THE DRAWINGS The invention and its advantages will be better understood on reading the detailed description given below of different embodiments of the invention given by way of nonlimiting examples. This description refers to the pages of attached figures, on which:

FIG. 1 represents a perspective view of a writing instrument,

- Figure 2 shows the writing instrument of Figure 1 exploded,

FIGS. 3A, 3B and 3C represent the different steps for replacing a writing element, seen according to the section plane III of FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS FIGS. 1 and 2 show a rechargeable writing instrument 10, in this example a multifunction writing instrument, comprising a body 12 and a plurality of writing elements 14, in this example four writing elements 14a, 14b, 14c and 14d. The body 12 extends in an axial direction X and in a radial direction R. The body 12 has a front end 12-1 having an orifice for the passage of writing tips and a rear end 12-2 opposite to the front end 12-1 in the axial direction X. Subsequently, and unless otherwise indicated, by "front" / "rear" means "disposed on the side of the front / rear end" In this example the body 12 comprises several parts, namely a front barrel 12a, a rear barrel 12b and a connecting piece 12c on which are mounted the front barrel 12a and the rear barrel 12b. In FIG. 1, the front barrel 12a is shown transparent so that the writing elements are visible. Of course, in reality, this barrel can be transparent or opaque. In Figure 2, the front barrel 12a is not shown. The rear barrel 12b has four side openings 12bl, in this case side windows, each receiving a button of a writing element (described below). The openings 12bl have a rectangular shape, the large side of which extends in the axial direction X and guide the buttons in the axial direction X. The buttons are radially free to move within the openings 12bl, in particular in the radial direction towards the outside RI. The rear edge 12bl 1 of each opening 12bl has an inclined face with respect to the axial direction X and forms a ramp oriented towards the outside of the body 12 in the axial direction oriented from the front end 12-1 towards the rear end 12-2 of body 12 (XI in FIG. 3A). An internal projection 11 forms an extension of the rear edge 12bl 1, inside the body 12, in the middle of the rear edge 12bll. The edge 12bll and the projection 11 form a radial guide ramp for the button.

The writing elements 14a, 14b, 14c are similar while the writing element 14d is different from the writing elements 14a, 14b and 14c. In this example, the buttons 13 of all the writing elements are identical. Of course, according to a variant, the buttons may be different from one writing element to another. In this example, the writing points 17 of the writing elements 14a, 14b and 14c are identical ball points while the point 18 of the writing element 14d is a mechanical mechanism. The button 13 of each writing element is connected to the writing tip by a reservoir, the reservoirs 17a of the writing elements 14a, 14b and 14c being ink reservoirs, each containing an ink of a color different from that other tanks, while the tank 18a of the writing element 14d is a mine tank. It is therefore understood that the writing element 14d is a mechanical pencil system.

In Figure 1, the writing element 14d is in the writing position, the tip 18 projecting from the body 12, while the writing elements 14a, 14b and 14c are in the retracted position, the tips of writings 17a being retracted into the body 12. Of course, in a manner known elsewhere, by activating a button of the writing element 14a, 14b or 14c, said writing element is brought into the writing position while that the writing element 14d automatically returns to the retracted position. For this automatic return to the retracted position, the writing elements 14a, 14b, 14c and 14d are each provided with a return spring 15.

A blocking element 16 extends partly inside the body 12, and more particularly in this example in the rear barrel 12b. The locking element 16 comprises a central portion

16a, in this example a plate 16a substantially square and extending transversely to the axial direction X. This plate 16a is disposed inside the body 12. A cylindrical portion 16b extends in the axial direction X from the center of the plate 16a towards the rear end

12-2 of the body 12. This cylindrical portion 16b extends partially inside the body 12 and, consequently, partially outside the body 12. Four fingers 16c extend in the axial direction X from the corners of the square formed by the plate 16a towards the front end 12-1, inside the body 12. Each finger 16c is engaged in a slide 12b2 of the body 12 extending in the axial direction X, thanks to what the locking element 16 is guided in translation in the axial direction X within the body 12 and is coupled in rotation about the axial direction X with the body 12. The fingers 16c are aligned with the edges of the long sides of the openings 12bl and cooperate with the buttons 15 13.

The internal ribs 16cl of the fingers 16c block radially inward of the body 12 the buttons 13 when the writing elements are in the retracted position. The ribs 16cl are shorter in the axial direction X than the fingers 16c and the openings 20bl, so that the buttons 13 can, after a certain axial stroke from the retracted position of the corresponding writing element, sinking radially towards the inside of the body 12. Thanks to this sinking, the return of the button 13 induced by the spring 15 is blocked by the axial end of the ribs 16cl adjacent to the button 13, which cooperates axially in abutment with the button 13. This is how the writing elements are blocked, via the buttons 13, in the writing position. As can be seen in FIG. 2, each button 13 has three radial projections, namely a front projection 13a, a rear projection 13b and an intermediate projection 13c disposed between the front projection 30a and the rear projection 13b. When a button 13 is moved towards the front end 12-1 and engages with the ribs 16cl so as to lock the corresponding writing element in the writing position. When another button 13 is moved d 'another writing element forward, the intermediate projection 13c of this button cooperates with the rear projection 13b of the button of the writing element in the writing position, whereby the button of the latter is released from the ribs 16cl and the corresponding writing element automatically returns to the rear, in the retracted position, thanks to the associated spring 15. The front projection 13a is mainly used for guiding the button 13. Of course, as an alternative, the writing instrument can be equipped with any other mechanism for retracting the writing elements.

The locking element 16 has portions forming radial stops 16d, in this example tabs 16d configured to cooperate radially in abutment with a radial shoulder 13d disposed at the rear of each button 13. These tabs 16d extend axially from the plate 16a, on the same side as the fingers 16c, and are adjacent to the fingers 16c. As can be seen in FIGS. 3A and 3B, the locking element 16 is movable in the axial direction X between a locking position (FIG. 3A) and a replacement position (FIG. 3B). In the blocking position, the tongues 16d partially close the openings 12bl and block the buttons 13, the writing elements of which are in the retracted position in the radial direction towards the outside RI. Of course, the tongues 16d are arranged radially outside relative to the shoulders 13d, and substantially opposite the shoulders 13d when the writing elements are in the retracted position. In this example, the distal end 16dl of the tongues 16d in the axial direction X forms an axial stop with which the buttons 13 cooperate axially when the corresponding writing element is in the retracted position. In other words, the springs 15 axially push the buttons 13 against the distal end 16dl of the tongues 16d.

In this example, when the writing elements are in the writing position, the shoulders 13d are no longer vis-à-vis the tabs 16d. However, the buttons 13 are engaged inside the body 12 when the corresponding writing element is in the writing position, and are therefore blocked radially outwards by the body.

12. In the replacement position, the tongues 16d are erased from the openings 12bl and authorize the movements in the radial direction towards the outside RI of the buttons 13, the writing elements of which are in the retracted position. In this example, the locking element 16 is unique and cooperates with all the buttons 13 of the plurality of writing elements 14 which are in the retracted position.

To move the locking element 16 between the locking position and the replacement position, the cylindrical portion 16b extends axially outward from the body 12, whereby the user can catch it and axially move the locking element 16. More particularly, in the locking position, an axial clearance J1 (see magnifying glass in FIG. 3A) is provided between the body 12 and the plate 16a, this axial clearance J1 corresponding to the maximum axial stroke necessary to erase the tabs 16d from the openings 12bl.

The locking element 16 has stops 16e which extend axially from the plate 16a on the side of the cylindrical portion 16b. These stops 16e are received in corresponding through holes 12d formed in the body 12, and can slide inside these holes 12d. In the blocking position, the stops 16e are flush with the external surface of the body 12, whereby a lock 20 can cooperate in abutment with the blocking element 16, in this example via the stops 16e, so as to block the movements according to the axial direction X in direction XI (in this example direction oriented from the front end 12-1 towards the rear end 12-2) of the locking element 16 to go to the replacement position from the locking position.

In this example, the latch 20 is a nut 20 forming a separate part of the locking element 16 and the body 12, which is mounted to play on the locking element 16. More particularly in this example, the latch 20 is mounted on the cylindrical portion 16b. The lock 20 has a radial web 20a having a circular through hole having a first diameter. The cylindrical portion 16b has a diameter greater than the first diameter except on a narrow portion 16bl whose diameter is less than the first diameter. Thus, the latch 20 is mounted on the cylindrical portion 16b by the radial web 20a engaged on the narrow part 16bl. To assemble, the lock 20 on the cylindrical portion 16b, the lock 20 is force fitted until the radial web 20a is in the clearance formed by the narrow part 16bl. The diameter of the narrow portion 16bl being less than the first diameter, a radial clearance is provided between the blocking element 16 and the latch 20, whereby the latch 20 is free to rotate around the axial direction X. It is therefore possible freely screw / unscrew the latch 20 on the corresponding thread 12e of the body 12 (ie the latch 20 therefore allows reversible locking). Furthermore, the narrow portion 16bl extends axially, and thus provides an axial clearance J2 between the radial web 20a and the locking element 16. In this example, the axial stroke C1 of the thread 12e is equal to the sum of the clearances axial J1 and J2 (ie C1 = J1 + J2), whereby when the bolt 20 is completely unscrewed, the locking element 16 is automatically driven, via the bolt 20, in the replacement position as shown in the Figure 3B.

To summarize, the latch 20 is mounted to play on the locking member 16, with an axial clearance J2. When the lock 20 is screwed onto the body 12, it cooperates in abutment with the locking element 16 so that the latter remains in the locking position and cannot come into the replacement position. When the latch 20 is unscrewed from the body 12, it cooperates in abutment with the locking element 16 and drives it into the replacement position. In this example, via the thread 12e, in the replacement position, the latch 20 blocks the return of the blocking element 16 to the blocking position, whereby the replacement of the writing elements (described below) is ease.

In the locking position, thanks to the axial clearance J2 between the latch 20 and the locking element 16, the locking element can be moved in the axial direction X in the direction X2 (in this example direction oriented from the rear end 12-2 towards the front end 12-1), opposite direction XI. Such displacement axially drives all of the writing elements 14. This makes it possible to actuate the mechanical mechanism 18 when the writing element 14d is in the writing position. Indeed, in the writing position, the mechanical pencil mechanism 18 can cooperate in support with the body 12, in this example with the internal surface of the front barrel 12a, thanks to which the mechanical pencil mechanism 18 is actuated. Thus, the displacement in the direction X2 of the blocking element 16 when the writing element 14d is in the writing position makes it possible to advance a lead within the mechanical mechanism 18.

The operations for replacing a writing element will now be described with reference to FIGS. 3A to 3C. For clarity of the figures, the springs 15 are not shown.

Figure 3A shows a configuration where all the writing elements are in the retracted position while the locking element 16 is in the locking position. Thus, all the buttons 13 are locked radially outward by the tongues 16d, and cooperate axially in abutment against the distal ends 16dl of the tongues 16d. In this configuration, the blocking element 16 is blocked by the latch 20 in the blocking position and can be moved forward by pushing the cylindrical portion 16b in the direction X2. Furthermore, each button 13 can be pushed in the direction X2 so as to bring the corresponding writing element into the writing position.

However, it is not possible to extract the buttons from the openings 12bl so as to remove the body writing elements

12. To do this, the locking element 16 must be brought into the replacement position. To bring the locking element 16 into the replacement position, the lock 20 is unlocked, in this example by unscrewing it from the body 12, which drives the locking element 16 from the locking position shown in FIG. 3A towards the replacement position shown in Figure 3B.

In the replacement position, the tongues 16d are no longer facing the shoulders 13d of the buttons 13, so that the buttons 13 are free to move radially outward from the body 12 (ie in the meaning RI). Each button 13 being opposite a ramp formed by an internal projection 11 and the rear edge 12bll of the corresponding opening 12bl, is guided radially outwards. Furthermore, in this example, each button 13 has an inclined face 13e configured to cooperate in sliding with this ramp, which makes it even easier to guide the button 13 radially outwards. In this example, the spring 15 of each writing element is configured to be compressed when the buttons 13 come into contact with the ramps. This makes it easier to eject the buttons but also guarantees a complete return of the buttons to the retracted position.

To extract the buttons radially outwards

13, the user can simply grab the button and pull it in this direction RI and / or slide it against the ramp formed by an internal projection 11 and the rear edge 12bll by pushing it in the direction XI. The button 13 thus drives all the corresponding writing element, in this example the writing element 14a, out of the body 12, as is represented by the arrow in bold in FIG. 3C.

To mount within the writing instrument 10 a replacement writing element, it suffices to carry out the reverse steps, namely to introduce a new writing element into the body 12, in a reverse movement to the arrow in bold in FIG. 3C, place the button of the new writing element within the opening 11 as shown in FIG. 3B, and lock the lock 20, in this example by screwing it onto the body 12 , whereby the locking element 16 is brought from the replacement position to the locking position, as shown in Figure 3A. It is noted that it is also possible to insert a button fitted with a replacement writing element in the in the body 12, even if the lock 20 is in the locking position, and this thanks to the slope 13e of the projection 13b of the buttons 13. Thanks to the spring 15, the button 13 will then automatically return to engagement with the latch 20.

Although the present invention has been described with reference to specific embodiments, it is obvious that modifications and changes can be made to these examples without departing from the general scope of the invention as defined by the revendications. In particular, individual features of the various illustrated / mentioned embodiments can be combined in additional embodiments. Therefore, the description and the drawings should be considered in an illustrative rather than restrictive sense.

For example, the writing instrument 10 comprises more or less than four writing elements. For example, the blocking element does not include fingers 16c.

It is also obvious that all the characteristics described with reference to a method can be transposed, alone or in combination, to a device, and conversely, all the characteristics described with reference to a device are transposable, alone or in combination, to a method.

Claims (9)

1. Refillable writing instrument (10) comprising a body (12) extending in an axial direction (X) and a radial direction (R) and having at least one lateral opening (12bl), at least one element of writing (14a, 14b, 14c, 14d) disposed inside the body (12) and comprising a writing tip (17, 18) and a button (13), the button (13) extending radially through of the opening (12bl) and making it possible to move the writing element (14a, 14b, 14c, 14d) between a retracted position in which the writing point (17, 18) is retracted in the body (12) , and a writing position in which the writing tip (17, 18) protrudes from the body (12), the button (13) being free to move towards the outside of the body (12) in the radial direction ( R) within the opening (12bl) whereby the writing element (14a, 14b, 14c, 14d) is removable from the body (12), and a blocking element (16) movable between a position of BlocA ge and a replacement position, in the blocking position the blocking element (16) cooperating with the button (13) so as to radially block the button (13) towards the outside of the body (12) at least when the writing element (14a, 14b, 14c, 14d) is in the retracted position, while in the replacement position the locking element (16) releases the button (13) radially towards the outside of the body (12), whereby the writing element (14a, 14b, 14c, 14d) can be removed from the body (12). 2. Writing instrument (10) according to claim 1, in which the blocking element (16) is movable relative to the body (12), a latch (20) making it possible to reversibly lock the blocking element (16) in the locking position relative to the body (12). 3. Writing instrument (10) according to claim 2, in which the latch (20) is mounted to play on the blocking element (16) or the body (12). 4. Writing instrument (10) according to claim 3, in which in the blocking position of the blocking element (16), the latch (20) cooperates in abutment with the blocking element (16) so as to block the movement of the locking element (16) to go to the replacement position. 5. Writing instrument (10) according to any one of claims 1 to 4, in which the blocking element (16) comprises an abutment portion (16d) configured to cooperate radially in abutment with the button (13) . 6. writing instrument (10) according to claim 5, wherein the stop portion (16d) is configured to also cooperate axially in abutment with the button (13). 7. writing instrument (10) according to any one of claims 1 to 6, wherein the opening (12bl) has an edge (12bl 1) configured to cooperate with the button (13) and guide the button (13 ) radially outward from the body (12) when the locking element (16) is in the replacement position. 8. writing instrument (10) according to any one of claims 1 to 7, in which the writing element (14d) is a mechanical pencil system comprising a mechanical pencil mechanism (18) and a mine tank ( 18a), the blocking element (16) in the blocking position being axially movable at least when the writing element (14d) is in the writing position so as to be able to advance a mine from the writing point (18). 9. writing instrument (10) according to any one of claims 1 to 8, comprising a plurality of writing elements (14a, 14b, 14c, 14d) and a single blocking element (16) configured to block radially, in the locked position, at least all of the writing elements (14a, 14b, 14c, 14d) which are in the retracted position.