FR2779991A1 - Writing tip for ball point pen - Google Patents

Abstract

The writing tip for a ball point pen has a bore (10) with a writing ball (2) extending partially outwardly and freely rotatably mounted in a seating (12). The bore is closed and has an intermediate ball (3) between the writing ball and a spring (4).

Description

The present invention relates to a pen tip and more.

  especially for ballpoint pens without ink flow regulator. In such pens, the point comprises an internal duct with a cylindrical cone enclosing a writing ball of which a part projects outside and which is mounted in free rotation in a

end housing.

  The writing ball is supplied directly with ink from

  a tubular tank connected to the tip conduit.

  The ink column contained in the reservoir is generally surmounted by a grease piston intended to prevent flow from the rear of the reservoir and to avoid the evaporation of the solvents entering the

ink composition.

  However, when the pen is stored with its tip down or when it is used for a long time, uncontrolled ink flows occur which can cause damage and lead to a very marked deterioration in the writing quality. . In addition, in the event of an impact on the rear part of the pen or if the pen is stored in a vertical position, tip up or even in a horizontal position, there is a withdrawal of the ink column, leading to feeding problems. in ink when resuming

  writing or being written.

  In addition, when the tip of such pens is not protected by a waterproof cap, the clearance between the writing ball and the wall of its housing allows the evaporation of the volatile solvents contained

  in the ink (especially in the case of an aqueous ink).

  This results locally in drying of the ink and the formation

  an artificial cap making the pen unusable.

  A technical solution to these problems consists in equipping the tip of the pen with an internal helical spring exerting a bearing force on the writing ball which is then pressed in the pen's rest position against an annular lip delimiting its housing towards outside

  and thus sealing it.

  During writing, the pressure exerted by the user on the pen compresses the spring, thereby releasing between the annular lip and the ball,

a passage for ink.

  However, the direct support contact of the spring on the ball limits its freedom of rotation and thus reduces writing flexibility. Furthermore, the installation of the helical spring inside the point, immediately behind the housing of the writing ball, requires the arrangement of the internal conduit so that its internal diameter is greater than the diameter of the turn d end of

  spring to allow contact with the ball.

  However, this arrangement sometimes results in an excessive reduction in the surface of the seat of the writing ball and in particular for balls.

small diameter.

  The use of a spring provided with a support element in the form of either a straight rod, as described in FR 2 729 966, or of an elongated part as described in EP 810 103, certainly allows , to keep a sufficient seat surface but allows to remain

  or even amplifies the problem linked to the excessive stiffness of writing.

  Indeed, despite the reduced contact surface between the ball and the rod, the forced rotation of the ball during writing generates significant friction leading to premature wear of the ball with deterioration of its surface state (appearance of streaks , grooves ...) and / or the rod (reduction in length ...). This wear leads to an overall decrease in the quality and regularity of writing due to the fact

  in particular that the sealing of the ball housing is no longer sufficient.

  In addition, when using the pen, the rotational movement of the writing ball in its housing displaces the end of the rod or of the elongated part which has a certain axial clearance in the internal conduit. This displacement results in a reduction in efficiency or even a malfunction of the spring, and the appearance during writing of

  small ink stains or different forms of line irregularities.

  In addition to the problems mentioned above, the technical solutions envisaged so far are difficult to achieve industrially if only because of the difficulties encountered

  for the precise positioning of the support element on the ball.

  Consequently, these solutions generate additional costs

specific and important.

  The object of the present invention is to solve the problems

  techniques posed by the solutions of the prior art.

  This object is achieved, according to the invention, by means of at least one intermediate ball disposed between the writing ball with which it is

  in contact and the end of said spring.

  According to an advantageous characteristic, the intermediate ball is

arranged on the axis of the point.

  According to another characteristic, said intermediate ball is housed in a bore provided, at least in its front part, with a

  necked forming a seat for the writing ball.

  According to a particular variant, said spring has a cylindroconical profile. According to another variant, said spring is helical and has an end turn of restricted diameter in bearing contact with the

intermediate ball.

  According to yet another variant, the contact between the ball

  intermediate and the writing ball is rotatable.

  Preferably, the end turn of the spring has a diameter such that the intermediate ball is partially housed in said end turn. According to another characteristic, the wall of the internal duct is provided at the level of the intermediate ball with a network of channels for

the passage of ink.

  According to another embodiment, said conduit contains a

  stacking of intermediate balls in mutual contact.

  In this case, the intermediate balls preferably have

  increasing diameters from front to rear of said conduit.

  According to yet another embodiment, the internal conduit

  contains a set of at least two juxtaposed intermediate balls.

  The ballpoint pens using the tip of the invention have an ink column which is stable in the reservoir and which does not generate

rest no leakage or evaporation.

  This tip allows regular and continuous writing without any disturbance even in the event of an impact on the back of the pen or

prolonged rest.

  The tip of the invention can be used both in fixed mode, for example in disposable type pens, and in retractable mode, for example.

  example, in refillable pens.

  Furthermore, the intermediate ball eliminates any risk of seizure and / or jamming whatever the stresses of the writing ball, which eliminates all the drawbacks linked to the relative displacement of the writing ball / spring connecting element. , and in

  especially writing faults.

  In addition, the assembly of the points of the invention is particularly easy and rapid because the intermediate ball is guided before coming to a stop axially in the cylindrical bore delimiting its housing and without it being necessary to carry out a

any prior orientation.

  The various constituent elements of the point being particularly simple and their assembly being easy, its price of

  returns is particularly economical.

  The present invention will be better understood on reading the

  description which will follow accompanied by the drawings on which:

  - Figure 1 shows a longitudinal sectional view of a first embodiment of the tip of the invention; - Figures 2a and 2b show detail views in longitudinal section of the embodiment of Figure 1 respectively in the rest position and in the writing position; - Figure 3 shows a partial view in cross section along AA of the tip shown in Figure 2b; - Figures 4 and 5 show views in longitudinal section of a second and a third embodiment of the tip of the invention. The tip shown in the figures is intended to be used

in a ballpoint pen.

  This point consists of a cylindroconical envelope 1 with a longitudinal axis X, delimiting an internal conduit 10 which encloses a writing ball 2, a part of which projects outside. The ball 2 which is used for writing is mounted in free rotation in a housing 12

  end delimited towards the outside by an annular lip 11.

  The conduit 10 and the housing 12 located in its extension forward, are intended to communicate rearwardly with an ink tank (not shown). The reservoir is connected to said tip, for example, by external fitting on a sleeve 14 secured to the rear part of the tip. The envelope 1 also contains a spring 4 intended to exert an axial support on the writing ball 2 in order to ensure a

  tight contact between said ball 2 and the annular lip 11.

  The spring 4 which is here a cylindroconical helical spring is

  housed in the internal duct 10 of the casing 1.

  The spring 4 is blocked in compression in the duct 10 by pressing its rear end turn against a retaining face carried either by the internal peripheral edge 14b of the sleeve 14, as

  shown in Figure 1 either by the end of the tank.

  The envelope 1 of the tip contains, according to the invention, at least one intermediate ball 3 disposed between the writing ball 2 with which it is in contact, possibly rotary, and the front end of the spring 4. In the case of a rotary contact, the intermediate balls have a

rolling function.

  In the embodiment of Figure 1, the tip contains only a single intermediate ball 3 which thus ensures transmission and

  centering of the resultant of the support forces exerted by the spring 4.

  The intermediate ball 3 is preferably arranged on the axis X of the point and is housed, for example, in a bore 13 shown in

detail in Figures 2a and 2b.

  The bore 13 consists of a front or downstream part 13a delimiting a constriction whose internal diameter is less than the diameter of the intermediate ball 3 and that of the writing ball 2. The rear or upstream part 13b of the bore 13 has a larger internal diameter which is substantially equal to the diameter of ball 3. The constriction of front part 13a also forms the seat of writing ball 2 in

  limiting its rearward movement.

  The connection zone 13c between the front 13a and rear 13b parts

  preferably has an internal wall of convex curvature.

  This arrangement allows the introduction of the ball into the bore

  13 through the rear hole 14a of the sleeve 14.

  The passage of the ink from the orifice 14a of the upstream part of the conduit 10 to the housing 12 of the writing ball 2 is carried out mainly via a peripheral network of channels 130 shown in

section in Figure 3.

  In FIG. 2a, the point is at rest (here in a horizontal plane) and the writing ball 2 is in sealed contact against the annular lip 11 so as to close the housing 12 and to prevent any outward flow from the ink (not shown) filling all

  the volume of the conduit 10 including the bore 13 and the housing 12.

  In this position, it is therefore not necessary for the intermediate ball 3 which is in contact with the writing ball 2 to be in abutment against the front part 13a of the constriction of the bore, which leaves

  possibly a slight play.

  In Figure 2b, the tip is supported on a writing medium. The writing ball 2 is then pushed backwards from its housing 12 against the front part 13a of the bore 13 forming a seat, thereby freeing a passage for the ink at the periphery of the lip.

ring finger 11.

  In this position, the intermediate ball 3 is held in bearing contact against the writing ball 2 by the spring 4 while being

  moved backwards in bore 13.

  As shown in FIGS. 1, 2a and 2b, the helical spring 4 has a writing turn 43 of restricted diameter so that the ball 3 is partially housed in the turn 43, while being

kept in support.

  In the embodiment of FIG. 4, the tip contains a train of intermediate balls 31, 32, 33 ... in mutual support contact,

possibly rotatable.

  The balls 31, 32 ... are arranged in the form of an axial stack and have increasing diameters from the front to the rear so as to be wedged laterally by contact with the wall of the duct 10 with cylindroconical profile. In this embodiment, the stack reaches a height substantially equal to that of the conical part of the conduit 10 so that the helical spring 4 is cylindrical with turns of

uniform diameter.

  The rear ball 33 located at the top of the stack is in contact with the front end of the spring 4 while the front ball 31

  is in contact with the writing ball 2.

  Fig 5 shows a detailed sectional view of a third

  embodiment of the tip of the invention.

  In this embodiment, the tip comprises a set of at least two intermediate balls 31, 32 juxtaposed. The balls 31, 32 are wedged laterally in possibly rotary contact, on the one hand, with the writing ball 2 of larger diameter, and on the other hand, with the wall of the

internal duct 10.

  A portion of the balls 31, 32 can be housed inside the

  front end turn 43 of spring 4 as shown in FIG. 5.

Claims (11)

  1. Pen tip of the type comprising an internal conduit (10) with a cylindroconical envelope containing, on the one hand, a writing ball (2) of which a part projects outside and which is mounted in free rotation in a housing (12) delimited towards the outside by an annular lip (11) and communicating with an ink tank connected to said tip and, on the other hand, a spring (4) intended to ensure the tight contact of said ball d writing with said annular lip (11), characterized in that said conduit (10) further contains at least one intermediate ball (3) disposed between said writing ball   (2) with which it is in contact and the end of said spring (4).   2. Tip according to claim 1, characterized in that said   intermediate ball (3) is arranged on the axis of the point.   3. Tip according to one of claims 1 or 2, characterized in   that said intermediate ball (3) is housed in a bore (13) provided, at least in its front part (13a), with a constriction forming a seat for the writing ball (2).   4. Tip according to one of the preceding claims,   characterized in that said spring (4) has a cylindroconical profile.   5. Tip according to one of the preceding claims,   characterized in that said spring (4) is helical and has an end turn (43) of restricted diameter in bearing contact with the ball intermediate (3).   6. Tip according to claim 5, characterized in that the end turn (43) of the spring (4) has a diameter such that the ball   intermediate (3) is partially housed in said end turn.   7. Tip according to one of the preceding claims,   characterized in that the wall of the internal conduit (10) is provided at the level of the intermediate ball (3) with a network of channels (130) for the ink passage.   8. Tip according to one of the preceding claims,   characterized in that the contact between the intermediate ball (3) and the writing ball (2) is rotatable.   9. Tip according to one of the preceding claims,   characterized in that said conduit (10) contains a stack of beads   intermediaries (31,32 ...) in mutual contact.   10. Tip according to claim 9, characterized in that said intermediate balls (31,32 ...) have increasing diameters of   front to rear of said conduit (10).   11. Tip according to one of claims 1 to 8, characterized in   that said internal conduit (10) contains a set of at least two balls   intermediate (31,32) juxtaposed.