WO2012168632A1 - Writing implement, in particular a marker, having a reloadable supply unit - Google Patents

Abstract

The invention relates to a reloadable marker implement (1), comprising: a tubular body (4) containing a supply unit (8) therein; a writing tip (2); a removable end piece (10) which seals a rear opening (6) of the tubular body (4), thus enabling the removal of the supply unit, and which has an inner portion (11) inserted into the tubular body in a loaded configuration of the implement; and an outer portion (12) provided with a profiled portion (14) for rotatably engaging with a cap (3) or a fitted key. The inner surface (9) of the tubular body has a cam system (24a, 24b) on the rear-opening side, the inner portion having a projection (30) forming a cam follower for guiding the removable end piece during the removal or fitting thereof. The rear opening is sealingly closed through the use of raised sealing areas (31, 32, 41, 42) located behind the cam system.

Description

 Writing instrument, in particular marker, with refillable tank unit

TECHNICAL FIELD OF THE INVENTION

 The present invention relates to writing instruments such as ink pens, and in particular to refillable marker instruments comprising:

 a tubular body extending longitudinally between a front end provided with a front opening and a rear end provided with a rear opening;

a reservoir unit which is housed in the tubular body removably and which has a front end and a rear end;

 a writing tip connected to the front end of the tank unit and mounted at the front end of the tubular body through the front opening;

 - A removable tip for closing the rear opening of the tubular body in a closed position, the removable tip having an outer portion and an inner portion inserted into the tubular body in a loaded configuration of the marker instrument in which the reservoir unit is in contact with said inner portion;

the inner portion of the removable tip having a generally tubular shape with an inner face and an outer face, and having a free end remote from the outer portion;

the outer portion having a profiled portion for a rotational engagement.

BACKGROUND OF THE INVENTION

A marker of the above kind makes it possible to replace the ink tank unit without having to discard the entire instrument. Thus the document DE 195 25 621 A1 discloses a marking instrument whose rear end has a profiled polygon-shaped section, complementary to a profile formed on the cap, thanks to which a rotation of the cap (when it is engaged with the profiled portion) allows to remove the rear end. This type of marker instrument makes easy the opening from the rear of the tubular body.

 For the introduction of the tip at the rear end of the body, the cap is however of no use and the user must make sure to push enough tip to obtain a seal. This operation can present difficulties for people lacking address or strength.

 There is therefore a need for marking instruments offering the user increased handling comfort for the charging operation.

GENERAL DESCRIPTION OF THE INVENTION

 The present invention aims to provide a rechargeable marker instrument that reduces mounting difficulties for the user.

For this purpose, the marker instrument according to the invention is characterized in that the tubular body has an inner face which has two diametrically opposed cam faces axially oriented towards the rear opening, the inner part of the removable end piece exhibiting on its outer face at least one protuberance located on the side of the free end and protruding radially outwards, the protuberance forming a cam follower adapted to abut on one of the cam surfaces so as to generate a relative movement of the removable tip relative to the tubular body to leave or reach the closed position (this thanks to which the removable tip can be ejected from the closed position to a position further back by a rotation actuation exerted on the outer part), at least one of the inner face of the tubular body and the outer face of said inner portion having reliefs forming a seal in said closed position, near the outer portion of the removable tip, a sealing contact between the tubular body and the inner portion of the removable tip, knowing that said protuberance is on the side of the free end at a greater distance from the outer part than the reliefs sealing.

 Thus, it is advantageously obtained a guiding effect of the rear nozzle over a short distance and the compressive force relative to the sealing contact is brief since it is produced only at the end of the assembly, taking into account the relative position of the sealing reliefs (further back) relative to the cam surfaces (further forward) for guiding the tip in position in the tubular body. The system defined by the cam surfaces ejects the removable tip by a brief rotational movement, typically exerted on the profiled portion using a key or appropriate tool.

 This configuration is also ergonomic and compact: it is not necessary to provide a long thread and the rotation of the tip can be less than 180 ° due to the use of cam surfaces diametrically opposed. For the user, it is understood that the mounting of the tip is made very comfortable.

According to one feature, two diametrically opposed protuberances are provided and located on the free end side, the two protuberances protruding radially outwards and forming each a cam follower adapted to bear on one of the cam surfaces when the endpiece cooperates with the tubular body. With this arrangement, a simultaneous double support is advantageously obtained and the risk of annoying deflection relative to the insertion axis is eliminated.

 According to a feature, each of the two cam surfaces has a concave shape with a bottom zone situated at a determined distance from the opening of the rear opening, the inner part of the removable end piece having a length substantially equal to said determined distance, said two protuberances projecting radially outwardly each defining a convex shaped surface towards the free end.

 With this arrangement, the guidance in rotation with the ramp is achieved until the complete depression and the introduction of the tip can be faster for the user. The concave profile of the ramp allows the realization of the depression regardless of the direction of rotation used and the ejection effect of the tip is obtained by simply rotating the outer portion in one direction or the other.

In another feature, the sealing reliefs comprise two annular reliefs formed on the inner face of the tubular body and placed closer to the rear end of the tubular body than the two cam surfaces. The use of two annular reliefs, near the rear end of the tubular body, improves the sealing. With an inner part of the tip which typically has a section which is reduced towards its free end, this arrangement makes it possible to better mark the final position of assembly of the endpiece. removable .

 In various embodiments of the rechargeable marker instrument according to the invention, one or more of the following provisions may also be used:

 - The sealing reliefs comprise a first annular bead and a second annular bead, present on the outer face of said inner portion of the removable tip, the second annular sealing bead being adjacent to the two radial protuberances, while the first annular sealing bead is offset longitudinally relative to the first bead towards said outer portion of the removable tip (this arrangement improves the seal without there being a surplus of effort to provide during the beginning of the insertion of the tip);

 the first annular bead and the second annular bead are spaced longitudinally by a first distance, while the two annular reliefs are spaced longitudinally by a second distance substantially equal to the first distance, locking the end piece in a sealed sealing position of the rear opening being obtained by engagement of said two annular reliefs with said first and second annular beads;

 - The tubular body and the removable tip extend longitudinally about the same longitudinal axis;

the inner portion of the removable tip extends about the longitudinal axis from a contact shoulder with the tubular body to a free end, the first annular sealing bead being adjacent to the shoulder; the inner part narrows forwards preferably from the first bead (thus obtaining a shape of the inner part which facilitates insertion);

 the first annular bead projects radially up to a first maximum distance from the longitudinal axis, the second annular bead protruding radially to a second maximum distance from the longitudinal axis, the second maximum distance being less than the first maximum distance (it is understood that with such a configuration of annular beads on two different levels, the user can insert the tip at the maximum in the tubular body without having effort to provide and must force only at the end of the race to lock the tip);

 the rear end of the tubular body has a progressive thinning circumferential zone in the direction of the rear opening of the tubular body, the sealing reliefs comprising an annular relief located in or behind said circumferential thinning zone and a annular relief located in front of said circumferential zone (this arrangement makes it possible to obtain a difference in level without creating a local surplus of height of the reliefs of the body and the beads of the internal part .The shape of the various reliefs can therefore be the same and this makes the mounting system more robust).

 According to another particularity, the marker instrument comprises a cap of generally tubular shape, the cap comprising:

 an end opening for inserting the front end of the tubular body into the cap,

 a bottom opposite said end opening, an inner face,

an external face, a first engagement device formed on the outer face of the cap, remote from the end opening, and arranged to engage with said profiled portion of the outer portion of the removable tip, to rotate the removable tip; and

 a second engagement device formed on the inner face of the cap and engaging with the front end of the tubular body in a closed position of the cap in which the writing tip is housed inside the cap.

 According to another feature, the profiled portion for a rotating engagement forms a free end of the outer portion of the removable tip and has a polygonal profile, preferably at least five sides. In the cap, the second engagement device has a complementary profile (forming for example a female member if the profiled portion of the removable tip forms a male member).

 According to another feature, the free end of the inner portion extends around the rear end of the reservoir unit and has a determined outer diameter D, the inner portion of the removable endpiece having a predetermined length L, the following relation being satisfied: 0.4 ≤ L / D ≤ 1.2. With this arrangement, a short back piece can be obtained which minimizes the amount of material used for the manufacture of the marker. In addition, the withdrawal of the tip is made particularly simple and fast, a partial rotation (less than 180 °) of this tip being sufficient using the complementary cap.

According to another feature, the two cam surfaces are contiguous and symmetrical, the two surfaces of cam coming together forming two diametrically opposite vertices. Thus, the insertion of the tip is considerably simplified since the insertion of the tip to the sealed contact occurs naturally, without there being any need beforehand to adjust the angular position of the tip.

BRIEF DESCRIPTION OF THE DRAWINGS

 Other features and advantages of the invention will become apparent from the following description of several embodiments, given by way of non-limiting examples, with reference to the accompanying drawings in which:

 FIG. 1 is an exploded view of a marker instrument according to a preferred embodiment of the invention;

 - Figures 2A and 2B show, respectively, a side view and an end view of the marker instrument of Figure 1 in the mounted state;

 FIG. 3 shows a longitudinal section of a marker instrument of the preceding figures;

 FIGS. 4A and 4B show two alternative positions of the cap on the rear end of the marker instrument of FIGS. 1-3;

 - Figure 5 shows in longitudinal section a detail of the tubular body of the marker instrument of the preceding figures;

 - Figures 6 and 7 show, respectively in profile view and in plan view, the removable tip of the marker instrument of Figures 1-4B;

FIG. 8 is a longitudinal sectional view showing the rear of the tubular body shown in FIG. Figure 5;

 - Figures 9A and 9B are views, respectively from below and in longitudinal section, of the removable tip of the marker instrument of Figures 1-4B;

 - Figure 10 is a longitudinal sectional view detailing a sealing zone of the removable tip of Figure 6;

 - Figure 11 shows a detail of an alternative embodiment of the inner portion of the removable tip;

 - Figure 12 is a top view illustrating an alternative embodiment of the outer portion of the removable tip. DESCRIPTION OF THE PREFERRED EMBODIMENTS OF

THE INVENTION

 In the various figures, identical references indicate identical or similar elements. The marker instrument 1 makes it possible to write by any writing, erasing or highlighting medium, hereinafter referred to as ink by means of a writing tip 2 made of felt or the like. This type of tip allows in a manner known per se to form a relatively broad line (for example of the order of 1 mm or more).

Referring to Figures 1 to 4B, the marker instrument 1 is provided with a cap 3 which covers the writing tip 2 in a closed position (position clearly visible in Figures 2A and 3). The cap 3 has a generally tubular shape and may optionally have external edges 3a or other similar reliefs facilitating the rotation of the cap 3 by a hand of the user. The instrument marker 1 comprises a tubular body 4 which extends longitudinally between a front end 4a with an opening 5 (front opening) and a rear end 4b with an opening 6 (rear opening). In the illustrated example, this tubular body 4 extends around a longitudinal axis A which forms a central axis.

 With reference to FIG. 3, the ink supply system 7 of the marker instrument 1 here has a reservoir unit 8 which is housed in the internal volume V of the tubular body 4 removably and which has a front end 8a. and a rear end 8b. The inner face 9 of the tubular body 4 may have a plurality of ribs 9a, for example formed at a distance from the front end 4a and the rear end 4b, in order to center the reservoir unit 8. These ribs 9a are here distributed around the outside. tank unit 8 and are at least four in number (six ribs 9a being used in the embodiment of Figure 3). The reservoir unit 8 may be generally cylindrical and the front end 8a has for example an opening through which the rear of the writing tip 2 enters the reservoir unit 8. This is a tip of felt. More generally, it is understood that the writing tip 2 is in communication with the front end 8a of the tank unit 8 and mounted at the front end 4a of the tubular body 4 through the front opening 5. The tubular body 4 can be formed in one piece. Alternatively, several pieces can be used to form the tubular body 4, for example with the combination of a cylindrical sleeve and a front end adapted to support the writing tip 2.

Of course, the ink supply system 7 can be made differently from the nonlimiting example of FIG. 3, for example with at least one intermediate element (additional reservoir, ink guiding cavity or any other connection interface) between the replaceable reservoir unit 8 and the writing tip 2.

 As can be seen in particular in FIGS. 1, 2A and 3, the rear opening 6 formed at the rear end 4b of the tubular body 4 is closed by a removable rear end piece 10. The removable end piece 10 has an internal part 11 which is inserted into the internal volume V of the tubular body 4 in the closed position (as illustrated in FIG. 3 in particular), the external part 12 then being arranged in the extension of the rear end 4b of the tubular body 4. The body tubular 4 and the removable tip 10 extend here longitudinally about the same longitudinal axis A. Alternatively, the longitudinal axis of the tip 10 could be offset relative to the longitudinal axis of the tubular body 4. In this case, it is understood that the rear opening 6 is also offset with respect to the axis of the tubular body 4.

 Referring to Figures 5, 6, a shoulder 13 is here formed at the front end of the outer portion 12 and abuts on the annular perimeter defined by the end 4b of the tubular body. The junction between the inner portion 11 and the outer portion 12 is here realized here in the plane defined by the shoulder 13. The removable tip 10 is preferably formed of a single molded piece of plastic.

 The outer portion 12 has a profiled portion

14 whose section is in the form of a polygon (see Figure 7). This form of polygon, here hexagonal is complementary to a profiled section wall 15 of the cap 3, visible in Figure 2B. With reference to the 7, the profiled portion 14 of the tip 10 may have rounded portions 14a between the straight segments 14b allowing the rotation to be taken up by the cap 3. Thus, when the cap 3 is engaged with the profiled portion 14, the user must simply turn the cap 3 to remove the removable tip 10. Of course the profiled portion 14 may have a different geometry to allow a rotating grip. Thus, in the example of Figure 12, an octagonal shape is used.

 Referring to FIGS. 2B, 3, 4A and 7, the profiled portion 14 for a rotating engagement here forms a free end of the outer portion 12 of the removable tip 10. The outer portion 12 further defines a cavity 12a which the cavity 12a is surrounded by the profiled portion 14 which forms an annular axial projection relative to the remainder of the outer portion 12.

 The cap 3 has a convex portion 3b surrounded remotely by the profiled section of the peripheral wall 15. The profiled portion 14 of the removable tip 10 defines a male member which is inserted axially into the rear end of the cap 3. More precisely , the profiled portion 14 of the marker instrument 1 shown in FIG. 2A is inserted in the groove 16 (female member) defined between the convex portion 3b and the profiled section wall 15, so as to be in engagement with the wall The shaped position between the cap 3 and the removable tip 12 is shown in particular in FIG. 4A.

In other words, the cap 3 has a first engagement device (15, 16) which extends on the side of the bottom 18 and rotates the removable tip 10. This first engagement device (15, 16 ) formed on the outer face of the cap 3 can of course be designed differently from the example shown in Figures 1-7. For example, the male and female parts may be inverted and other non-circular geometrical shapes (preferably with the presence of longitudinal edges) may be used.

 Figure 4B shows the cap 3 turned over the tip 10 with respect to Figure 4A. Indeed, it can also be attached to the outer portion 12 of the removable tip 10, preferably without rotation. The cap 3 has for this purpose a second engagement device which is here formed on the inner face 3c of the cap 3. This second device may comprise at least one internal annular bead B visible in FIG. 3 or a similar relief, formed on the internal face 3c, in position adjacent to the end opening 17 through which the front end 4a of the tubular body 4 can be inserted. This internal bead B engages in a peripheral groove 12b (visible in FIG. 6) formed on the outer portion 12 of the removable end piece 10. In this nonlimiting example, the same internal bead B of the cap 3 engages with protruding reliefs 18 formed on the tubular body 4, on the side of the front end 4a, for locking a closed position of the cap 3 as illustrated in FIGS. 2A and 3.

It is understood that the cap 3 may have any shape adapted to cover the front end 4a of the tubular body 4, with a bottom 18 opposite the end opening 17. The method of fixing by an internal bead B of the cap 3 n is given as an illustration (and for example could alternatively use an annular relief such as a bead on the outer face of the tubular body 4, which cooperates with point reliefs formed on the inner face 3c of the cap 3).

 It is further understood that the first engagement device (15, 16) of the cap 3 can be considered optional, an equivalent tool can be used to rotate the outer portion 12 of the removable tip 10.

 The removable tip 10 and its cooperation in the marker instrument 1 will now be more particularly described in connection with Figures 3, 5-6 and 9A-9B.

 As shown in Figures 3 and 9A-9B, the inner portion 11 of the removable tip 10 has for example a generally tubular shape with an inner face fl and an outer face f2, the outer face f2 being adapted to engage with the inner face 9 of the tubular body 4 at the rear end 4b. The inner portion 11 has a free end 11a distant from the outer portion 12 and which extends around the rear end 8b of the tank unit 8 in the loaded configuration of the marker instrument 1 shown in FIG. internal part is then inserted into the tubular body 4 so as to bear on the reservoir unit 8. The bearing contact or contacts are made by the inner face of a cavity 11b defined by the inner portion 11, this cavity 11b communicating axially with the interior volume V.

 The length L of the inner part 11 is restricted, so that here the following relation is verified:

 0, 4 <L / D <1,

where D represents the determined external diameter D defined at the free end 11a. With this arrangement the inner part 11 is particularly reduced. Of more, the rear end 8b of the tank unit 8 is not here held tight by the tip but is only guided and centered by penetrating into the cavity 11b. It can thus be seen in the loaded configuration of the marker instrument 1, as illustrated in FIG. 3, that the reservoir unit 8 is in contact over a short length (much shorter than the length L of the inner portion 11 and visibly less at L / 3) with the inner part 11 of the removable end piece 10. In this loaded configuration, the writing tip 2 then protrudes into the tank unit 8 and can be fed with ink from the tank unit 8.

 FIGS. 9A and 9B illustrate the arrangement of the cavity 11a for correctly positioning the reservoir unit 8. Ribs 20 which tap towards the free end 11a are provided on the inner face fl of the inner part 11 to perform the centering function of the tank unit 8. The thinning of the ribs 20 widens the passage for the tank unit 8. The ribs 20 can extend to near the free end 11a. A spider 21 or other similar relief (for example in the form of Y or Z) may be formed in the bottom 22 of the cavity 11a to form a contact abutment with the rear end 8a of the tank unit 8. The brace 21 (which limits the depth of the cavity 11b, so the possibility of depression of the reservoir unit 8 in the inner portion 11) and the beveled shape of the ribs (which limits the contact with the tank unit 8) allow here to prevent blocking of the tank unit 8 in the inner part 11, so that the tank unit 8 can be disengaged from the tubular body 8 alone after removal of the removable tip 10.

With reference to FIGS. 5 and 6, the displacement relative to the removable end piece 10 relative to the tubular body 4 to obtain the closed position can be achieved naturally by a depression of the inner portion 11 of the removable tip 10 through the rear opening 6. The correct angular positioning is obtained by using a cam system formed on the inner face 9 of the tubular body 4, close to the rear end 4b.

 As can be seen in FIG. 5, this cam system here has two cam surfaces 24a, 24b that are diametrically opposed and axially oriented toward the rear opening 6. Each of the two cam surfaces 24a, 24b has a concave shape with a zone the distance x1 is substantially equal to the length L of the inner part 11 of the removable end piece 10.

 The inner portion 11 has on its outer face f2 at least one protrusion 30, and preferably two protuberances 30 located on the side of the free end 11a and projecting radially outwardly. Each of these protuberances 30 forms a cam follower adapted to abut on one of the cam surfaces 24a, 24b. When the inner portion 11 of the removable tip 10 is pushed through the rear opening 6, the central axis of the tip 10 and the central axis of the rear opening 6 are aligned and each protuberance 30 abuts on the convex cam surface 24a or 24b vis-a-vis.

 In this example, the two cam surfaces 24a and

24b are contiguous and symmetrical, and meet by forming two vertices 26 diametrically opposed. Each cam surface 24a or 24b then has two ramps each extending respectively from one or the other vertices 25 to the bottom 25. According to the angular position initially taken by the removable tip 10, the protrusion 30 visible in Figure 6 can come to bear:

 - Or on the portion of the cam surface adjacent to one of the vertices 26 (rear portion of a ramp closer to the opening 6);

 or on the portion of the cam surface adjacent to the bottom (front part of a ramp farther from the opening 6);

 - Or directly on the bottom 25, which corresponds to the case where the removable tip 10 has an angular position compatible with the closed position shown in Figure 3. In the first two cases, the support of the protrusion 30 on the cam surface 24a or 24b causes the inner portion 11 of the removable tip 10 to sink into the tubular body 4, with rotation until the protrusion is in contact with the bottom 25 of the cam surface. corresponding 24a or 24b. The presence of two cam surfaces 24a, 24b makes it possible to reduce the rotational movement to an angle less than 180 °, and even less than 90 ° in the example shown with symmetrical cam surfaces 24a, 24b, regardless of the angular position. initial of the removable tip 10 at the beginning of the depression through the rear opening 6.

With reference to FIG. 6, it can be seen that the protrusion 30 protrudes radially outwardly by defining a convexly shaped surface towards the free end 11a. The convex shaped surface is preferably rounded. Thus, during the operation of removing the removable tip 10, the cam system with two cam surfaces 24a, 24b allows, smoothly, eject the removable tip 10 to a position further back than the closed position when the outer portion 12 is actuated in rotation.

 In the embodiment shown in FIG. 6, two diametrically opposite protuberances 30 are formed on the outer face f2 of the inner part. These protuberances 30 are here in the form of half-cylinder with a rounded front end 30a which bears on the cam system of the tubular body 4. In order to avoid deforming or digging the cam surfaces 24a, 24b concave, it is preferable that the radius of curvature at the front end 30a of the protrusion 30 is large, for example greater than or equal to 2 or 3mm. This further provides a reversibility to the cam system during relative movement of the removable tip 10 to leave or reach the closed position. The protuberances 30 are for example relatively narrow so as to extend angularly on less than one eighth of the periphery of the outer face.

Of course, other shapes than the half-cylinder can be used (for example a crown portion) and it is possible to use two protuberances 30 that are not symmetrical. Figure 11 thus shows one of the protuberances 30 with a profile stretched on the sides to extend angularly about a quarter of the periphery of the outer face f2. The use of two non-symmetrical, cam-specific surface protuberances 24a or 24b may be advantageous, for example to maintain continuity in an external design of the marker instrument 1. It is also understood that the cam surfaces 24a, 24b can be arranged differently from the illustrated example. According to another embodiment, at least one of the vertices 26 can be replaced by a rounded with a small radius of curvature.

 With reference to FIG. 3, the shut-off position is obtained with one or two sealing zones each defined by an annular sealing contact C1, C2 which circumscribes the inner part 11 of the removable end piece 10. Preferably, the sealing contact C1 and / or C2 occurs only at the end of the introduction of the removable tip 10, due to a position of the sealing zones backwards relative to the system. The inner face 9 of the tubular body 4 and / or the outer face f 2 of the inner part 11 have sealing reliefs (41, 42; 31, 32) for the obtaining the sealing contact or contacts C1, C2 near the outer part 12 of the removable end piece 10.

 With reference to FIG. 5, the end 4b of the tubular body 4a may be provided with two annular sealing protrusions 41, 42 or sealing rings which project radially towards the longitudinal axis A from the internal face 9. Annular sealing reliefs 41, 42 are close to the rear end 4b of the tubular body and thus arranged further back than the two cam surfaces 24a, 24b. With the use of a generally frustoconical shape of the inner portion 11 of the removable tip 10, it is understood that the sealing contacts C1, C2 can be obtained only when the removable tip is sufficiently depressed and in a position angular correct.

With reference to FIG. 8, the two annular reliefs 41, 42 are spaced longitudinally by a distance d2 which may represent more than one-fifth of the length L of the internal part 11 (for example of the order d one third of the length L). These annular reliefs 41, 42 are rounded and preferably circular when the rear end 4b of the tubular body 4 has a circular cross section.

 Figures 6 and 10 show that the outer face f2 may have a first annular bead 31 and preferably also a second annular bead 32. In the marker instrument 1 illustrated in the figures, the first annular bead 31 and the second annular bead 32 are spaced longitudinally by a distance d1 substantially equal to the distance d2 and can each cooperate with one and the other respectively of the two annular reliefs 41, 42 to form a plastic sealing contact (C1 and C2 respectively ). This secures the removable end piece 10 in the closed position of the rear opening 6 and a seal with respect to the outside.

 It can be seen in FIG. 6 that the second annular sealing bead 32 is adjacent to the two radial protuberances 30, while the first annular sealing bead 31 is offset longitudinally with respect to the first annular bead 31 in the direction of said outer portion. 12. In addition, the first and second annular beads 31, 32 are staggered on two different levels and thus extend at different distances from the longitudinal axis of the removable tip 10. The inner portion 11 has a generally frustoconical shape with a cross-sectional section which narrows to the free end 11a. Therefore, the first annular bead 31 projects further (radially outward) than the second annular bead 32 closer to the free end 11a.

We can also see in Figures 5 and 8 that the rear end 4b of the tubular body 4 has a circumferential zone 44 of progressive thinning in the direction of the rear opening 6, complementary to the frustoconical shape of the inner part 11 of the removable end piece 10. One of the reliefs d annular sealing (here the annular relief 41) is located in this zone 44 or behind this zone 44, while the other annular relief 42 is located further forward inside the tubular body 4. It is understood that this annular relief 42 is then complementary to the second directory bead 32.

 With this arrangement, the user can insert the inner portion 11 of the removable tip 10 at most in the tubular body 4 without having effort to provide, and it is only at the end of the race that the user must force the insertion to obtain the sealing contact or contacts Cl, C2 which lock the removable end piece 10 in its closed position.

 To facilitate the locking, it can be provided a slope 36 greater than 15 °, for example of the order of 22 °, in front and in the extension of the second annular bead 32, to facilitate the insertion of the removable tip 10. The second annular bead 32 can thus more easily penetrate beyond the annular sealing relief 41 closest to the rear opening 6 and then gradually press on the annular sealing relief 42 complementary to the tubular body. 4, which is furthest from the rear opening 6.

One of the advantages of the invention lies in the ease of correctly mounting the removable tip 10 on the rear end 4b of the tubular body 4, or the sealing contacts C, C2 being obtained at the end of the establishment. of the removable tip 10. We understand with this arrangement that when using the marker instrument 1, the removable tip 10 is firmly attached to the tubular body 4 and can not be removed accidentally. For disassembly, the effort to be provided is also brief and is requested at the very beginning of the operation, the cam system then guiding the ejection towards the rear of the removable tip 10. In concrete terms, this initial effort is not felt as a difficulty by the user because of the torque effect obtained by using the "key" formed by the cap 3 or another tool of suitable shape.

 It is understood that each of the examples and each of the details of embodiment described above can be used alone or in combination. It should be obvious to those skilled in the art that the present invention allows embodiments in other specific forms without departing from the scope of the claimed invention.

Claims

Rechargeable marker instrument (1) comprising:  a tubular body (4) extending longitudinally between a front end (4a) provided with a front opening (5) and a rear end (4b) provided with a rear opening (6);  - a reservoir unit (8) which is housed in the tubular body (4) removably and which has a front end (8a) and a rear end (8b);  - a writing tip (2) which is connected to the front end (8a) of the tank unit (8) and which is mounted at the front end (4a) of the tubular body through the front opening (5); a removable end piece (10) for sealing the rear opening (6) of the tubular body (4) in a closed position, the removable end piece having an external part (12) and an internal part (11) inserted in the tubular body (4) in a charged configuration of the marker instrument in which the reservoir unit (8) is in contact with said inner portion (11); the inner portion (11) of the removable tip (10) having a generally tubular shape with an inner face (fl) and an outer face (f2), and having a free end remote from the outer portion, said inner portion (11 ) having on its outer face (f2) at least one protrusion (30) projecting radially outwards; the outer portion (12) having a profiled portion (14) for rotating engagement, at least one of the inner face (9) of the tubular body (4) and the outer face (f2) of said inner portion (11) having sealing reliefs (31, 32, 41, 42) forming in said closed position, close to the outer part (12) of the removable end piece, a sealing contact between the tubular body (4) and the inner part (11) of the removable end piece ( 10) characterized in that the tubular body (4) has an inner face (9) which has two cam surfaces (24a, 24b) diametrically opposed and axially oriented towards the rear opening (6), the sealing reliefs extending near the outer portion (12) of the removable tip, said protuberance (30) being located on the side of the free end (11a), at a greater distance from the outer part than said reliefs sealing, and forming a cam follower own to rely on one of cam surfaces (24a, 24b) so as to generate a relative movement of the removable tip (10) relative to the tubular body (4) to leave or reach the closed position.  Marker instrument according to claim 1, wherein said at least one protuberance (30) comprises two diametrically opposed protuberances and located on the free end (11a) side, the two protuberances protruding radially outwardly and forming each a cam follower adapted to abut on one of the cam surfaces (24a, 24b). Marking instrument according to claim 2, wherein each of the two cam surfaces (24a, 24b) has a concave shape with a bottom zone (25) located at a determined distance (xl) from the opening of the rear opening, the inner portion (11) of the removable tip (10) having a length (L) substantially equal to said determined distance (xl), said two protuberances (30) protruding radially outwardly each defining a shape surface convex towards the free end (11a).  Marker instrument according to any one of the preceding claims, wherein said sealing reliefs comprise two annular reliefs (41, 42) formed on the inner face (9) of the tubular body (4) and placed closer the rear end (4b) of the tubular body as the two cam surfaces (24a, 24b).  Marker instrument according to any one of the preceding claims, wherein said sealing reliefs comprise first and second annular beads (31, 32) present on the outer face (f2) of said inner portion (11) of the detachable tip (10), the second annular sealing bead (32) being adjacent to the two radial protuberances (30), while the first annular sealing bead (31) is offset longitudinally with respect to the first annular bead (31). ) towards said outer portion (12).  Marker instrument according to claim 4 and claim 5, wherein the first annular bead (31) and the second annular bead (32) are spaced longitudinally by a first distance (d1), while the two annular reliefs of sealing (41, 42) are longitudinally spaced a second distance (d2) substantially equal to the first distance (dl), a locking of the removable end piece (10) in a sealing position of said rear opening (6) ) being obtained by engagement of said two annular reliefs (41, 42) with said first and second annular beads (31, 32). Marker instrument according to any one of the preceding claims, wherein the tubular body (4) and the removable tip (10) extend longitudinally around the same longitudinal axis (A). Marking instrument according to claim 7 taken in combination with any of claims 5 and 6, wherein the inner portion (11) of the movable tip (10) extends about the longitudinal axis (A). from a shoulder (13) of contact with the tubular body (4) to a free end (11a), the first annular sealing bead (31) being adjacent to the shoulder (13).  Marker instrument according to claim 5 or And one or other of claims 7 and 8, wherein the first annular bead (31) projects radially to a first maximum distance from the longitudinal axis (A), the second annular bead (32). protruding radially to a second maximum distance from the longitudinal axis (A), the second maximum distance being less than the first maximum distance.  10. marker instrument according to claim 9, wherein the rear end (4b) of the tubular body (4) has a progressive thinning circumferential zone (44) towards the rear opening (6) of the tubular body, said sealing reliefs comprising an annular relief located in or behind said circumferential thinning zone and an annular relief located in front of said circumferential zone.  The marker instrument according to any one of the preceding claims, comprising a cap (3) of generally tubular shape, the cap comprising:  an end opening (17) for inserting the front end (4a) of the tubular body (4) into the cap, an opposite bottom (18) to said end opening, an internal face,  an external face,  a first engagement device (15, 16) formed on the outer face of the cap (3), remote from the end opening (17), and arranged to engage with said profiled portion (14) of the external portion (12) of the removable tip, for rotating the removable tip (10); and a second engagement device (B) formed on the inner face of the cap (3) and engaging with the front end (4a) of the tubular body in a closed position of the cap in which the writing tip ( 2) is housed inside the cap (3).  Marking instrument according to any one of the preceding claims, wherein the profiled portion (14) for a rotating engagement forms a free end of the outer portion (12) of the removable tip (10) and has a polygonal profile. .  Marking instrument according to any one of the preceding claims, wherein the free end (11a) of the inner part (11) of the removable end piece (10) extends around the rear end (8b) of the reservoir unit (8) and has a determined external diameter D, the inner portion (11) of the removable tip having a determined length L, the following relationship being satisfied: 0.4 <L / D <1.  A marker instrument according to any one of the preceding claims, wherein the two cam surfaces (24a, 24b) are contiguous and symmetrical, the two cam surfaces joining together forming two diametrically opposite peaks (26).