EP1827869B1 - Writing instrument comprising a cartridge holder - Google Patents

Description

The present invention relates to writing instruments.

More particularly, the invention relates to a writing instrument comprising a drum extending along a longitudinal axis, a cartridge arranged inside the drum and having a front end connected to a writing tip and a rear end, a cartridge holder connected to the barrel and against which the rear end of the cartridge is supported.

In the prior art, there are supports of this type having a flat base substantially perpendicular to the longitudinal axis against which the rear end of the cartridge bears. These supports have the advantage of being easy to make and require a small amount of plastic. However with these supports the rear end of the cartridge is not immobilized which can have a detrimental effect on the operation of the withdrawal mechanism of the tip and can create rattling noises giving the user an impression negative on the quality of the instrument.

Other media (see for example DE-U-9114693 ) have a cylindrical well-shaped housing in which the rear end of the cartridge is inserted more or less tightly. However, these supports have the disadvantage of being suitable for cartridges having a rear end of substantially constant diameter, which poses problems when it is desired to use this support with cartridges having a substantially constant diameter. slightly different shape. In addition, this type of support requires more complex molds to form both the side walls of the support and the recessed housing receiving the cartridge.

The object of the present invention is to provide a cartridge holder adapted to receive substantially different shaped cartridges without, however, excessively increasing the amount of material and the complexity of the molding.

For this purpose, according to the invention, a writing instrument of the kind in question is characterized in that the cartridge holder comprises a base extending in a plane substantially transverse to the longitudinal axis and at least three studs. extending generally along the longitudinal axis from the base towards the front, each of said pads having an inner face oriented towards the longitudinal axis which forms an acute angle with the portion of the longitudinal axis extending towards the front end from the base, and between which is wedged the cartridge.

Thanks to these provisions, the cartridge is automatically positioned between the pads arranged on the base of the support during assembly of the various elements composing the writing instrument, and bears against the pads so as to be substantially parallel to the longitudinal axis.

• les faces intérieures sont planes et définissent au moins un cercle inscrit entre elles situé dans un plan transversal par rapport l'axe longitudinal, et de préférence coaxial à la base ;
• chaque plot présente une face extérieure orientée radialement vers l'extérieur, et au moins une face latérale s'étendant entre la face intérieure et la face extérieure, lesdites faces de l'ensemble des plots étant agencées les unes par rapport aux autres et présentant chacune une forme adaptée pour que l'ensemble des plots soit démoulable selon une direction radiale;
• l'instrument comporte trois plots, et un premier et un deuxième plot sont agencés en dehors d'un angle aigu, dit angle de dépouille, défini par deux plans parallèles à l'axe longitudinal et sécants en dehors de la base, cet angle présentant un sommet, et dans lequel le troisième plot est agencé dans ledit angle de dépouille;
• le troisième plot présente deux faces latérales qui forment un angle dont le sommet est dirigé vers le sommet de l'angle de dépouille et est situé plus près du sommet de l'angle de dépouille que le premier et le deuxième plot, la face latérale du premier plot et la face latérale du deuxième plot formant de préférence l'angle de dépouille ;
• les plots sont répartis angulairement de manière régulière ;
• la cartouche est sollicitée contre le support au moyen d'un ressort ;
• le support est relié au fût par un mécanisme de sortie et de rétractation de la pointe d'écriture ;
• le mécanisme est une pièce intégralement moulée avec le support.

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

• the inner faces are flat and define at minus a circle inscribed between them situated in a plane transverse to the longitudinal axis, and preferably coaxial with the base;
• each stud has an outer face oriented radially outwards, and at least one side face extending between the inner face and the outer face, said faces of the set of pins being arranged relative to each other and having each a shape adapted for all the pads to be demoldable in a radial direction;
• the instrument comprises three studs, and a first and a second stud are arranged outside an acute angle, said draft angle, defined by two planes parallel to the longitudinal axis and secants outside the base, this angle having a top, and wherein the third pad is disposed in said draft angle;
• the third stud has two lateral faces which form an angle whose apex is directed towards the apex of the draft angle and is located closer to the vertex of the draft angle than the first and the second stud, the lateral face of the first pad and the side face of the second pad preferably forming the rake angle;
• the studs are distributed angularly in a regular manner;
• the cartridge is biased against the support by means of a spring;
• the support is connected to the barrel by an output mechanism and retractation of the writing tip;
• the mechanism is a piece integrally molded with the support.

• serrage des deux demi-coquilles contre leur plan de joint,
• d'injection d'une matière plastique, et
• de démoulage en écartant les deux demi-coquilles selon la direction radiale de démoulage.

Furthermore, the invention also relates to a method of manufacturing a writing instrument comprising a molding operation of the cartridge holder in which a mold is provided in two parts which are half-shells, each part having a joint plane and reliefs corresponding to the lateral faces of the studs, and comprising the steps of:

• tightening the two half-shells against their joint plane,
• injection molding of a plastic material, and
• demolding by separating the two half-shells in the radial demolding direction.

Other features and advantages of the invention will become apparent from the following description of one of its embodiments, given by way of non-limiting example, with reference to the accompanying drawings.

• la figure 1 représente une vue en coupe longitudinale d'un instrument d'écriture comprenant un support de cartouche selon l'invention,
• la figure 2 représente une vue en perspective du support de cartouche selon l'invention,
• la figure 3 représente une vue de face du support de cartouche,
• la figure 4 représente une vue en coupe transversale d'un moule adapté pour réaliser le support de cartouche.

On the drawings:

• the figure 1 represents a longitudinal sectional view of a writing instrument comprising a cartridge holder according to the invention,
• the figure 2 represents a perspective view of the cartridge holder according to the invention,
• the figure 3 represents a front view of the cartridge holder,
• the figure 4 is a cross-sectional view of a mold adapted to provide the cartridge holder.

In the different figures, the same references designate identical or similar elements.

The figure 1 represents a writing instrument 10 which comprises a tubular shaft 12 extending along a longitudinal axis Z between two ends. A front end 12a has a passage 14 for a writing tip 16. Said writing tip 16 is connected directly to a front end of a cartridge 18 which extends along an axis substantially parallel to the longitudinal axis Z. The second end 12b of the drum receives a support 20 against which the rear end of the cartridge 18 bears.

The cartridge 18 is biased against the support 20 by means of a spring 22, arranged between bosses of the cartridge and the conical inner wall of the front end 12a of the drum located near the writing tip. The spring 22 cooperates with an output mechanism and retraction of the writing tip 16, to bring and maintain the writing tip 16 in a writing position or in a storage position. The mechanism is in one piece integrally molded with the support 20. The mechanism has an elastic arm 23 provided with projecting buttons 24 which cooperate with windows made in the barrel to block the cartridge 18 and therefore the writing tip 16 , in one or other of the positions described above.

The cartridge 18 is supported on the support at its rear end by at least three points of contact, ensuring good stability. The support 20 has a base 26 extending in a transverse plane perpendicular to the longitudinal axis Z. The base 26 has a surface of substantially identical shape to the inner section of the shaft 12, which is here substantially circular but it could be polygonal so as to slide freely with a small clearance in the shaft 12. The base 26 is concentric with the shaft 12.

The base 26 further comprises three studs 28, 30, 32 distributed angularly in a regular manner on the circular surface of the base 26. Each stud 28, 30, 32 extends generally along the longitudinal axis Z from the base 26 towards the writing tip 16. Each of the three pads 28, 30, 32 has an inner face 28a, 30a, 32a oriented towards the longitudinal axis Z and forming an acute angle with the longitudinal axis, so that the top of the angle formed by the intersection of the longitudinal axis Z and the plane defined by the inner face 28a, 30a, 32a of a stud 28, 30, 32 is directed towards the rear end 12b of the barrel 12.

The inclination of the inner faces 28a, 30a, 32a of the pads 28, 30, 32 guides the rear end of the cartridge 18 to a position in which it is in contact with each of the three pads, and therefore wedged , and this for cartridges having a rear end of substantially variable diameter. It is also possible for a cartridge 18 of smaller diameter than its rear end rests directly on the base while being centered by the pads 28, 30, 32.

The inner faces 28a, 30a, 32a of the three studs 28, 30, 32 are flat and define a plurality of circles inscribed together in a transverse plane. perpendicular to the longitudinal axis coaxial with the base 26. This arrangement guides the rear end of the cartridge 18 so as to center the cartridge 18.

In the case where the dimensions of the cartridge 18 are equal to those of one of the circles listed above, the rear end of the cartridge then bears on each of the three pads at a point.

The pads 28, 30, 32 also have an outer face 28b, 30b, 32b, oriented radially outwardly, and having a convex shape conforming to the inner wall of the barrel 12, for sliding therein.

A first 28 and a second 30 pads each have a single side face 28c, 30c which extends between the inner face 28a, 30a and the outer face 28b, 30b. A third stud 32 has two lateral faces 32c, 32d extending between the inner face 32a and the outer face 32b. As shown in figure 3 , the lateral face 28c of the first stud 28 is located in a plane P1 passing through the lateral face 32c of the third stud 32, and the lateral face 30c of the second stud 30 is located in a plane P2 passing through the second lateral face 32d of the third plot 32.

The planes P1, P2 mentioned above are perpendicular to the base 26, and parallel to the axis Z. They form an angle α said draft angle, and are intersecting along a straight line located outside the base 26. On the figure 3 , a point of this line is represented by the reference S which corresponds to the vertex of the angle α. The angle formed by the two planes, says clearance angle α, is about 5 ° in the embodiment shown, but could be between 2 ° and 15 °, to facilitate demolding without excessively reducing the size of the pads.

The crown S of the clearance angle α is situated on the side of the third stud 32, so that the third stud 32 is closer to the vertex S of the clearance angle α than the first 28 and second studs 30.

As a variant embodiment, the third stud 32 could be included in the clearance angle α with side faces 32c, 32d forming an angle directed towards the vertex S of the draft angle α. The side faces 32c, 32d would not be coplanar with the side faces 28c, 30c of the first 28 and second 30 pads.

The arrangements described above make it possible to wedge the cartridge 18 on the support 20 in an easy, fast and reversible manner. This assembly can therefore be done with fairly large manufacturing tolerances. Which decreases the manufacturing cost.

In addition the arrangement of the pads 28, 30, 32 allows easier manufacture, which will be better understood on reading the following.

The pads 28, 30, 32 are made by molding, by means of a mold 36 in two parts 38, 40, which are in the form of half-shells. Each part of the mold 36 has reliefs corresponding to the lateral faces and the inner faces of the studs.

The figure 4 represents a cross-sectional view of the mold 36 when the two parts 38, 40 are brought together so as to form the imprint of the studs 28, 30, 32 on the base 26. In this figure, the hatched portions correspond to the section of the two parts 38, 40 of the mold 36, which will be slightly in front of the base 26 of the support 20, during molding. The two parts of the mold extend beyond the circle delimited by the base 26, and have a joint plane J.

The parts of the mold represented inside the circle drawn in dotted line on the figure 4 , this circle representing the perimeter of the base 26.

The first portion 38 of the mold has a parallelepiped-shaped relief 42, in which two opposite faces 44, 46 are intended to mold the lateral faces 28c, 30c of the first and second studs 28, 30, and a central face 48 is intended to mold the inner face 32a of the third stud 32.

The other reliefs 50, 52 shown on the figure 3 belong to the second portion 40 of the mold 36. Each other relief 50, 52, said second relief, has a triangular shape whose facing sides 54, 56 form the imprint of the side faces of the third stud and the opposite sides 58, 60 form respectively the inner face 28a, 30a of the first 28 and second 30 pads.

The two opposite faces 44, 46 of the first relief 42 are arranged on planes having an angle substantially corresponding to the relief angle α cited above. So after molding the side faces 28c, 30c of the first and second pads 28, 30 are oriented relative to each other according to said clearance angle α.

The sides 54, 56 of the second reliefs 50, 52 of the mold, which form the imprint of the lateral faces 32c, 32d of the third stud 32, are also oriented relative to each other along said clearance angle α, since the sides 54, 56 of the second reliefs 50, 52 each pass through the same plane as that of each of the two opposite sides 44, 46 of the first relief 42.

Thus after molding, each lateral face 32c, 32d of the third stud 30 extends in the same plane as respectively the lateral face 28c of the first stud and the side face 30c of the second stud. What has the advantage of having a mold with reliefs simpler to achieve.

The second reliefs 50, 52 of the mold 36 cooperate with the first relief 42, so as to make the other faces of the different studs 28, 30, 32.

After injection of the material, the two parts 38, 40 of the mold 36 are removed in a radial direction R with respect to the longitudinal axis Z and in an opposite direction. On the figure 4 this direction corresponds to the bisector of the draft angle α.

The inner, lateral and outer faces of the pads 28, 30, 32 have a normal direction or a curvature oriented so that it can be demolded in the radial direction R.

These provisions make it easy to demold in a radial direction the base 26 with the pads 28, 30, 32.

In order to be able to use a two-part mold to easily demold the part, the draft angle α and the angle formed by the two lateral faces 32c, 32d of the third stud 32 must have their vertex S towards the same direction.

If the side faces 32c, 32d of the third stud 32 have an angle different from the clearance angle α, the width of the inner face 32a of the third stud 32 must be included in the clearance angle α.

These provisions make it possible to ensure easy demolding of the base 26 and pads 28, 30, 32.

Claims (10)

1. A writing instrument comprising:

   - a barrel (12) extending along a longitudinal axis (Z),

   - a cartridge (18) housed inside the barrel (12) and having a front end connected to a writing point (16) and a rear end, and

   - a cartridge support (20) connected to the barrel (12) and against which the rear end of the cartridge (18) rests,

   characterized in that the cartridge (18) support (20) comprises a base (26) extending in a plane lying approximately transversely to the longitudinal axis (Z) and at least three teeth (28, 30, 32) extending generally parallel to the longitudinal axis (2) from the base (26) forward, each of said teeth (28, 30, 32) having an inner face (28a, 30a, 32a) turned toward the longitudinal axis (Z) and forming an acute angle with the portion of the longitudinal axis extending toward the front end from the base (26), the cartridge (18) being wedged between said teeth.
2. The writing instrument as claimed in the preceding claim, in which the inner faces (28a, 30a, 32a) are planar and define, inscribed between said faces, at least one circle lying in a transverse plane with respect to the longitudinal axis (Z), and preferably coaxial with the base (26).
3. The writing instrument as claimed in either of the preceding claims, in which each tooth (28, 30, 32) has an outer face (28b, 30b, 32b) facing radially outward, and at least one lateral face (28c, 30c, 32c, 32d) extending between the inner face (28a, 30a, 32a) and the outer face (28b, 30b, 32b), said faces of the assembly of teeth (28, 30, 32) being set out with respect to each other, and each being shaped, in such a way that the assembly of teeth (28, 30, 32) is demoldable in a radial direction.
4. The writing instrument as claimed in claim 3, comprising three teeth and in which first and second teeth (28, 30) are arranged outside of an acute angle (α) , termed the clearance angle, defined by two planes (P1, P2) parallel to the longitudinal axis (Z) and intersecting outside of, the base (26), this angle having a vertex S; and in which the third tooth (32) is arranged inside said clearance angle (α).
5. The writing instrument as claimed in claim 4, in which the third tooth (32) has two lateral faces (32c, 32d) that form an angle whose vertex is toward the vertex (S) of the clearance angle (α) and is situated nearer to the vertex (S) of the clearance angle (α) than the first (28) and second (30) teeth, the lateral face (28c) of the first tooth and the lateral face (30c) of the second tooth (30) forming preferably the clearance angle (α).
6. The writing instrument as claimed in any one of the preceding claims, characterized in that the teeth (28, 30, 32) are distributed at regular angular intervals.
7. The writing instrument as claimed in any one of the preceding claims, in which the cartridge (18) is pressed against the support (20) by means of a spring (22).
8. The writing instrument as claimed in any one of the preceding claims, in which the support (20) is connected to the barrel (12) by a mechanism for extending and retracting the writing point.
9. The writing instrument as claimed in the preceding claim, in which the wriling-poirit extension and retraction mechanism is a component molded integrally with the support (20).
10. A method of making a writing instrument as claimed in one of claims 3 - 9, characterized in that it comprises a cartridge support (20) molding operation in which a mold (36) is supplied in two parts (38, 40) that are mold halves, each part (38, 40) having a parting line (J) and reliefs corresponding to the lateral faces (28c, 30c, 32c, 32d) of the teeth (28, 30, 32),
    and comprising the following steps:

    - clamping the two mold halves (38, 40) against their parting line (J),

    - injecting a plastics material, and

    - demolding by separating the two mold halves (38, 40) in the radial demolding direction.

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