pencil

Abstract

The invention relates to a pencil with a housing having a longitudinal axis, a lead held in a lead holder and a first adjusting apparatus which is designed to adjust the lead in the direction of the longitudinal axis with respect to the lead holder. According to the invention, a second adjusting apparatus is provided, which is designed to adjust the lead holder in the direction of the longitudinal axis between two operating positions with respect to the housing, namely a rest position, in which the lead is retracted with respect to the housing, and a working position, in which the lead protrudes axially out of the housing.

Description

[0001] PENCIL

[0002] The invention relates to a pencil with a housing having a longitudinal axis, a lead held in a lead holder and a first adjusting apparatus which is designed to adjust the lead in the direction of the longitudinal axis with respect to the lead holder.

[0003] Pencils of the type mentioned at the beginning are known. These are, for example, lead, colored, wax crayons or cosmetic pencils with a lead that wears away. Such pencils are fitted with mechanisms that allow the tip protrusion to be adjusted. Examples include mechanical pencils such as clutch pencils, propelling pencils and fine lead pencils.

[0004] As a rule, it is not possible to reliably set the tip protrusion of the lead to a constant value by a simple movement. Instead, it must be tried and tested, and the extent of the protrusion must be reviewed. For this reason, the tip is often not retracted after the pencil has been used, which can lead to the risk of damage or unintentional contamination of the surrounding area in the case of sensitive leads.

[0005] Therefore, the invention is based on the object of further developing the pencil of the type mentioned at the beginning in such a way that the tip protrusion of the lead can always be set to the same value in a simple manner and there is no risk of damage or unintentional contamination of the environment after use.

[0006] According to the invention, the object set for a pencil of the type mentioned at the beginning is achieved in that a second adjusting apparatus is provided which is designed to adjust the lead holder in the direction of the longitudinal axis between two operating positions with respect to the housing, namely a rest position in which the lead is retracted with respect to the housing, and a working position in which the lead protrudes axially out of the housing.

[0007] By combining the two adjusting apparatuses, the advantages of both can be combined in a single device. In particular, the above object can be achieved in a particularly simple way by the suitable design of the two adjusting apparatuses.The second adjusting apparatus can be a mechanism that can be switched between two end positions, in particular a locking mechanism (also known as a ballpoint pen mechanism).

[0008] This solution is therefore based on generally known pencil designs.

[0009] The first adjusting apparatus is preferably a continuously adjustable mechanism, in particular a rotary mechanism or a drop-lead mechanism.

[0010] The lead protrusion can be adjusted with particular precision using a

[0011] rotary mechanism.

[0012] According to a further preferred embodiment of the invention, the housing has a first housing part and a second housing part which can be twisted relative to one another about the longitudinal axis, wherein the two housing parts are each rotationally coupled in the working position to one of two parts of the first adjusting apparatus which can be twisted about the longitudinal axis.

[0013] In this design, twisting the two housing parts against each other causes the lead to move in relation to the lead holder in the direction of the longitudinal axis. The lead protrusion can therefore be precisely adjusted by the aforementioned twisting.

[0014] It is conceivable that the first and second housing parts are rotationally coupled not only in the working position, but also in the rest position of the pencil with one of the two parts of the first adjusting apparatus that can be twisted relative to each other about the longitudinal axis. Alternatively, in the rest position, at least one of the two housing parts cannot be rotationally coupled to either of the two parts of the first adjusting apparatus that can be twisted relative to each other about the longitudinal axis.

[0015] In other words, according to this embodiment of the invention, the first adjusting apparatus cannot be actuated in the rest position by twisting the two housing parts relative to one another. Rather, the two housing parts can be twisted against each other without this having any influence on the position of the lead in the longitudinal direction in relation to the lead holder. This prevents unintentional displacement of the lead in relation to the lead holder in the rest position, in which the lead is usually not visible. Rather, the two housingparts that can be twisted against each other can be played with without this having a detrimental effect on the position of the lead in relation to the lead holder.

[0016] In order to realize the above effect, it is particularly preferable according to the invention that at least that part of the two parts of the first adjusting apparatus which can be twisted relative to one another about the longitudinal axis which, in the rest position, is not rotationally coupled to any of the housing parts which can be twisted relative to one another about the longitudinal axis, is displaceable relative to the housing in the direction of the longitudinal axis.

[0017] It is therefore only necessary to ensure that the part of the two parts of the first adjusting apparatus which can be twisted relative to one another about the longitudinal axis, which is rotationally coupled to one of the housing parts which can be twisted relative to one another about the longitudinal axis in the working position, but not in the rest position, is displaced within the housing in the direction of the longitudinal axis for adjustment between the rest position and the working position, in order to cancel or effect said rotary coupling.

[0018] According to the invention, the rotary coupling for realizing the rotary mechanism of the first adjusting apparatus and / or the second adjusting apparatus can be realized in any desired manner. Polygonal profiles and / or a tongue-and-groove combination are preferably used for the corresponding rotary coupling.

[0019] This provides a particularly simple method of rotary coupling, which also has the advantage that it can be established or released as required by simply moving it in the direction of the longitudinal axis.

[0020] However, disengaging the first mechanism in this way can lead to the second mechanism being blocked when moving from the rest position to the operating position if the rotational position of the housing parts has previously been changed. If the housing parts are positioned unfavorably in relation to each other, a spring on the circumference of the lead insert may hit a spring in the inner profile of the housing, or in the case of a polygonal profile, the corners of the polygon on the circumference of the lead insert may hit the center of the surfaces in the inner profile of the housing, so that the housing of the first mechanism does not retract into the inner profile of the pencil housing.This can be avoided by sharpening the surfaces of the springs of both mechanisms that engage first. This creates a torque between the housing of the first mechanism and the pencil housing, which aligns the two. In the case of a polygonal profile, such a torque can be generated if the surfaces of the polygonal profile in the inner profile of the housing expand in a triangular shape in the direction of travel when switching from the rest position to the operating position, starting with an inner diameter large enough to accommodate the circumference of the polygonal profile of the first mechanism, until the inner diameter is completely described by the polygon.

[0021] With a polygonal profile, however, such self-centering is only possible if the torque for adjusting either the first mechanism or the two housing parts of the pencil that can be twisted in relation to each other is smaller than the torque that can be generated between the two mechanisms by this gradual transition of the inner profile of the housing from a circular to a polygonal profile. However, this torque decreases as the ordinal number of the polygon increases.

[0022] On the other hand, a polygonal profile with a low ordinal number (e.g., a triangle) requires a considerably larger internal diameter in the rear area of the front part of the housing than, for example, a hexagonal or octagonal profile on the first mechanism. However, the diameter of the pencil housing also increases as the ordinal number of the polygon decreases. A compromise must therefore be found between small external dimensions and sufficient torque when engaging the polygons when switching from the rest position to the operating position.

[0023] In the present development, the emphasis is on compact dimensions with the simultaneous choice of a polygonal profile in order to ensure sufficient torque for spinning out the core of the rotary mechanism tool during the injection molding process. Therefore, the preferred solution here is to maintain the coupling of the first mechanism with the housing of the pencil.

[0024] According to the invention, the rotary mechanism is preferably self-locking.

[0025] This ensures that pressure on the working end of the lead does not cause it to retract.Finally, according to the invention, a resilient apparatus is preferably provided which biases the lead holder in the direction of the rest position with respect to the housing.

[0026] This makes it easy to return the second adjusting apparatus to the rest position.

[0027] During the development of the mechanism, it was surprisingly discovered that wedging of the polygonal profiles can occur if the tolerances between the profiles of the first mechanism and the pencil housing are selected too generous and the corners of the polygonal profiles are rounded off too much. This wedging hinders the switching movement to change from the rest position to the operating position. Therefore, depending on the combination of materials, both parameters have narrow limits.

[0028] For a material pairing with a low coefficient of friction, for example polyoxymethylene (POM) for the first mechanism and polypropylene (PP) for the housing of the pencil, the maximum values for the corner radius Ri of the inner polygon with a width across flats S of the polygonal profile of ordinal number n are

[0029] 0 < Ri< 0,004 • S

[0030] in combination with the tolerance d between the surfaces of the polygonal profiles

[0031]

[0032] Alternatively, the addition of a straight guide should be considered when using a polygonal profile to prevent wedging.

[0033] In the following, the invention is explained in more detail with reference to the enclosed drawing, by means of preferred embodiments with further details. In the figures

[0034] Fig. 1 views of two embodiments of the pencil according to the invention,Fig. 2 perspective views of the individual parts of the pencils according to Fig. 1, Fig. 3 views of a rotary mechanism in the pencils according to Fig. 1,

[0035] Fig. 4 parameters S, d and Riusing the example of a hexagonal profile, Fig. 5 a combination of polygonal profile and tongue-and-groove straight guide, Fig. 6 an alternative rotary mechanism with tongue and groove guide of the front part of the housing, and

[0036] Fig. 7 the front housing part of the pencil, matching the alternative

[0037] rotary mechanism.

[0038] The pencils depicted in the drawings each have a housing 10, which includes a rotary cone 12, a grip sleeve 14 and a shaft 16. The grip sleeve 14 is encased in a soft grip component 18. The housing 10 has a longitudinal axis L. The shaft 16 encloses an inner tube 17.

[0039] A lead holder 20 is located in the housing 10, which is realized in the form of a lead tube in the exemplary embodiments shown. A lead 22 is inserted in the lead tube 20.

[0040] A first adjusting apparatus 24, which includes a spindle 26 and a driver 28 in addition to the rotary cone 12, is used to adjust the lead 22 with respect to the lead tube 20 in the direction of the longitudinal axis L.

[0041] A second adjusting apparatus is overall labeled with the reference number 30. It includes a pusher 32, a plunger 34, a spacer with switching star 36 and a first spring 38. A second spring is marked with the reference number 40.

[0042] In the case of the exemplary embodiments of the pencil according to the invention shown in the drawings, the second adjusting apparatus is a so-called locking mechanism, which is usually used in ballpoint pens. It is used to move the lead tube 20 back and forth between a rest position shown in Figures 1 a1) and 1 b1) and a workingposition shown in Figures 1 a2) and 1 b2). If, for example, the pusher 32 is actuated in the rest position shown in Fig. 1 a1), the plunger 34 and with it the spacer with the switching star 36 moves against the restoring force of the spring 38, causing the lead tube 20 to move to the left inside the housing 10 in the direction of the longitudinal axis L in Fig. 1. This displacement takes place against the restoring force of the second spring 40.

[0043] If the pusher 32 is then released, it is pushed back by the restoring force of the first spring 38, but due to the ballpoint pen mechanism used (locking mechanism), the lead tube 20 remains in the position displaced to the left, i.e., in its working position as shown in Fig. 1 a2) or 1 b2), in which the lead 22 protrudes from the housing 10.

[0044] If the pusher 32 is actuated again in the working position, the ballpoint pen mechanism (locking mechanism) causes the lead tube 20 with the lead 22 in it and the spacer with the switching star 36 in Fig. 1 to move to the right in relation to the housing 10 due to the restoring force of the second spring 40, so that the rest position according to Fig. 1 a1) and Fig. 1 b1) is reached again.

[0045] In both exemplary embodiments of the pencil according to the invention shown in Fig. 1, the lead 22 can be adjusted in the working position by means of the first adjusting apparatus 24 in the direction of the longitudinal axis L with respect to the lead tube 20. To do this, the rotary cone 12 must be twisted about the longitudinal axis L in relation to the grip sleeve 14. It is therefore snapped onto the grip sleeve 14, which is why it can be rotated about the longitudinal axis L in relation to the grip sleeve 14, but cannot be moved longitudinally in relation to the grip sleeve 14. Furthermore, the rotary cone 12 is rotationally coupled to the lead tube 20 by means of a polygonal inner profile via a corresponding polygonal outer profile on the lead tube 20. For this reason, the lead tube 20 rotates with the rotary cone 12. The driver 28, which is rotationally coupled to the lead tube 20 but can be moved longitudinally, is located in the lead tube 20. For this purpose, it protrudes with a shoulder 42 into a slot 44 in the lead tube 20. In addition, the shoulder 42 meshes with the internal thread of the spindle 26, which in turn is held in the grip sleeve 14 so that it cannot rotate. Matching polygonal structures on the spindle 26 on the one hand and the grip sleeve 14 on the other serve this purpose.Due to the couplings depicted in detail above, a twisting of the rotary cone 12 about the longitudinal axis L with respect to the grip sleeve 14 causes a displacement of the driver 28 and thus of the lead 22 within the lead tube 20 in the direction of the longitudinal axis L. In other words, the first adjusting apparatus 24 is a rotary mechanism. The individual conditions are selected in such a way that the rotary mechanism is self-locking.

[0046] This allows the protrusion of the lead 22 from the housing 10 to be adjusted by twisting the rotary cone 12 relative to the grip sleeve 14 in the working position.

[0047] In the rest position, the design according to Fig. 1 b1) is exactly the same as in the working position, because in this exemplary embodiment, the rotary cone 12 is also rotationally coupled to the lead tube 20 in the rest position via relevant polygonal profiles.

[0048] The exemplary embodiment according to Fig. 1 a1) and 1 a2) is different: In this exemplary embodiment, the rotary cone 12 is not rotationally coupled to the lead tube 20 in the rest position because the axial length of its inner polygon does not extend to the outer polygon of the lead tube 20. Rather, in this exemplary embodiment, the rotary cone 12 is freely rotatable relative to the grip sleeve 14 in the rest position, without such rotation being transmitted to the lead tube 20. In this exemplary embodiment, the rotary cone 12 is decoupled from the lead tube 20 in the direction of rotation in the rest position.

[0049] The mutually facing end faces of the polygons of the rotary cone 12 on the one hand and / or the lead tube 30 on the other hand are chamfered in order to prevent blocking when moving from the rest position to the working position. The same applies when using tongue-and-groove combinations.

[0050] In both embodiments of the invention, the lead 22 is protected in the rest position without having to be (laboriously) retracted into the lead tube 20 by means of the first adjusting apparatus 24, because it can be retracted into the housing 10 together with the lead tube 20 by means of the second adjusting apparatus 30.

[0051] Fig. 4 shows an example of the rotary coupling of the rotary cone 12 with the lead tube 20 using polygonal profiles. In particular, the corner radius Ri of the innerpolygon, the width across flats S of the polygonal profile and the tolerance d between the surfaces of the polygonal profiles can be seen.

[0052] Fig. 5 shows the same rotary coupling, but for a combination of polygonal profile and tongue-and-groove straight guide.

[0053] Fig. 6 shows a design of the lead tube 20 with lead 22 inserted therein and bars for a tongue-and-groove straight guide.

[0054] Finally, Fig. 7 shows a design of the rotary cone 12 matching the lead pipe 20 according to Fig. 6.

[0055] The features of the invention disclosed in the above description, the claims and the drawing can be essential both individually and in any combination for the realization of the invention in its various embodiments.

Claims

CLAIMS1. A pencil havinga housing (10) with a longitudinal axis (L),a lead (22) held in a lead holder (20) anda first adjusting apparatus (24) which is designed to adjust the lead in the direction of the longitudinal axis with respect to the lead holder,characterized bya second adjusting apparatus (30) which is designed to adjust the lead holder (20) in the direction of the longitudinal axis (L) between two operating positions with respect to the housing (10), namelya rest position in which the lead (22) is retracted with respect to the housing, and a working position in which the lead protrudes axially from the housing.

2. The pencil according to claim 1, characterized in that the second adjusting apparatus (30) is a mechanism which can be switched between two end positions, in particular a locking mechanism.

3. The pencil according to claim 1 or 2, characterized in that the first adjusting apparatus (24) is a continuously adjustable mechanism, in particular a rotary mechanism or a drop-lead mechanism.

4. The pencil according to claim 3, characterized in that the housing (10) has a first housing part (12) and a second housing part (14) which can be twisted relative to one another about the longitudinal axis (L), wherein the two housing parts are each rotationally coupled in the working position to one of two parts (20, 26) of the first adjusting apparatus (24) which can be twisted relative to one another about the longitudinal axis.

5. The pencil according to claim 4, characterized in that, in the rest position, the two housing parts (12, 14) are rotationally coupled to the respective associated one of the two parts (20, 26) of the first adjusting apparatus (24) which can be twisted relative to one another about the longitudinal axis (L).

6. The pencil according to claim 4, characterized in that, in the rest position, at least one of the two housing parts (12, 14) is not rotationally coupled to any of the two parts (20, 26) of the first adjusting apparatus (24) which can be twisted relative to one another about the longitudinal axis (L).

7. The pencil according to claim 6, characterized in that at least that one of the parts (20, 26) of the first adjusting apparatus (24) which can be twisted relative to one another about the longitudinal axis (L), which in the rest position is not rotationally coupled to any of the housing parts (12, 14) which can be twisted relative to one another about the longitudinal axis, is displaceable relative to the housing (10) in the direction of the longitudinal axis.

8. The pencil according to any of claims 4 to 7, characterized in that polygonal profiles and / or a tongue-and-groove combination are used for the rotary coupling.

9. The pencil according to any of claims 2 to 7, characterized in that the rotary mechanism is self-locking.

10. The pencil according to any of the preceding claims, characterized by a resilient apparatus (40) which biases the lead holder (20) in the direction of the rest position with respect to the housing (10).

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