HK1095301B - Lead for writing, drawing and painting utensils - Google Patents

Description

Refill for writing, drawing or painting instruments

Technical Field

The invention relates to a refill for writing, drawing and painting instruments, comprising a refill core which releases color in the direction of the longitudinal axis and at least one refill coating, wherein the at least one refill coating surrounds the refill core when viewed in cross section of the refill, and the refill coating and the refill core are immovably fixed to one another.

Background

Refills for writing, drawing or painting instruments are basically known.

Known writing or painting cartridges are usually designed as one-piece cartridges or chalk (Kreide) and are fixed in position or movably in a housing.

The prior art is a one-piece, uniformly designed cartridge, which is a compromise according to the desired writing properties, which can be adjusted primarily by the hardness of the cartridge and which represents the cartridge strength necessary for this use. If the minimum core strength is undershot, the core cross section can usually only be increased in order to increase the load-bearing capacity of the core in this way. In this case, it can be seen as a disadvantage that the increase in the diameter of the refill and the refill material consumed thereby lead to a considerable increase in the price of the refill. Furthermore, it is also considered to be disadvantageous that an increased core diameter has a negative influence on the pressing speed (pressgeschwidtigkeit), the drying time and the heat energy consumption.

From DE-GM 1201339 and patent application DE-H142675, multicolored refills are known, wherein refills of different colors are placed in an alternating manner. Multicolor strokes can be realized by the pen core or the pen. A disadvantage in the writing leads and the pens produced therefrom is that, despite the staggered arrangement of the differently colored shells, no improvement in the bending strength is achieved in comparison with the monochrome leads, which leads to the pen breaking easily as is known.

A fired pencil lead and a method for producing it are also known from DE 4332582 a 1. In this type of refill, the refill material is pressed in such a way that one or more layers are arranged in the radial direction between the central region and the outer peripheral region at a distance from the outer peripheral region, in which the filling is positioned in a concentric, tubular manner, wherein the filling is positioned in any desired or radial manner in the remaining region of the refill. In this case, expensive production methods are disadvantageous. An example of this is the very high shear energy which occurs in the extruder by the flake-like additive in this process, which greatly reduces the extrusion efficiency.

Furthermore, it is a significant disadvantage that the strength increase achieved in this way is not sufficiently high in order to indicate that the costs of production are appropriate. The used or inserted core material is identical over the entire core cross section, which leads to a high consumption of valuable core material which is necessary only in the writing area or tip area.

Disclosure of Invention

The object of the present invention is therefore to provide a fired or unfired refill for writing, drawing or painting, which does not have the disadvantages described above and which has a high loadability in particular with respect to external forces, without changing the refill formulation used for the color-releasing material, the so-called refill core. The aim is to reduce the tendency of the writing element to break due to high writing and sharpening forces.

According to the invention, a refill for writing, drawing and painting instruments is proposed, which has a color-releasing refill core and at least one refill cladding in the direction of the longitudinal axis, wherein the at least one refill cladding surrounds the refill core and the refill cladding and the refill core are immovably fixed to one another, as seen in a cross-section of the refill, wherein the at least one refill cladding has a higher bending strength than the refill core. The following measures lead to advantageous embodiments and further developments of the invention.

A refill for writing, drawing or painting is understood to mean, on the one hand, a refill which is fixedly inserted into wood or other sharps-able material and, on the other hand, a refill which is held in a rigid housing so as to be displaceable. For this purpose, for example, pencils or crayons are accommodated in wood, fine writing cores for mechanical pencils, so-called push-type pencils, and writing cores for automatic pencils.

These cartridges usually have an outer diameter in the range from about 0.3mm to 6 mm. These pencil leads or colored leads can be either burnt or unfired leads. The invention is also used in wax-based drawing chalk.

The object is achieved by a cartridge according to the invention having at least one cartridge envelope which extends substantially concentrically around the central axis of the cartridge core or the cartridge. The cartridge core may have a composition according to the prior art. The core cladding surrounding the core functions as a support cladding. In order to increase the stability of the cartridge against fracture, the support cladding has increased strength. It is possible to configure the support cladding surrounding the core in color, wherein the color used can contain information about the manufacturer, hardness, core type or marking width, for example. By differentiating the color of the writing core coating from the color of the writing core, a uniquely marked and visually perceptible feature is provided, which visually informs the user or user, via a color circle formed on the conical surface, that a high-value writing core has been obtained on the sharpened writing core.

It is proposed, by way of example, that by cladding a core produced from known core materials according to the prior art, the bending rupture strength of the core is significantly increased by 20 to 60% compared with a core without cladding according to the prior art, both in the case of graphite cores and in the case of colored cores, with the same overall cross section.

Even with such a high increase in the bending rupture strength of the cladded lead, the overall cross-section of the cladded lead can be reduced without loss of strength compared to an unclad lead according to the prior art. Cost savings are a direct result.

The production cost can be significantly reduced by using inexpensive clad raw materials.

Furthermore, it has been shown that fluctuations in mass and manufacturing tolerances of the core material can be compensated or compensated for by the unique coating.

The composition of the material used for the cladding region can generally be manufactured from inexpensive starting materials which are less expensive than the core of the cartridge which is accurately adjusted to the desired writing characteristics. For example, clay may be used instead of graphite. The core cladding serves only as a support cladding during normal handling of writing, drawing or painting instruments accommodated in the wood and is furthermore only cut away without use when the user writes with the core cladding.

In this embodiment of the refill, it is advantageous that, despite the increased strength provided by the cladding material surrounding the refill core, no impairment of the writing quality occurs, since the refill core, like the integral refills (vollmines) produced hitherto according to the prior art, can have the same composition.

On the other hand, the refill core can be used for coating refills, which are significantly more optimized with regard to the writing properties, since the strength is significantly increased by the coating.

The cross section of the cartridge can be configured in a circular, elliptical, triangular, hexagonal, right-angled or virtually any configuration. But here preferably circular.

One or more cartridge envelopes may be concentrically disposed about the cartridge core. The concentric design ensures that the writing element has the same strength and writing properties regardless of the writing position and thus regardless of the pressing load in all directions.

If there are multiple core claddings or cladding regions, then each individual cladding may have a different color and/or composition.

In order to produce high-quality cladded pen cores, the following boundary conditions should be met. In this regard, the sheath of a cartridge configured according to the invention should:

having the same or similar plasticity as the core,

the flowability of the cladding material approximately corresponds to the flowability of the core material,

the cladding material has a higher bending rupture strength than the core material,

the shrinkage of the cladding is adapted to the core material in order to avoid the formation of cracks during the drying process and the firing process,

the boundary or boundary surface between the cladding region and the writing core is preferably formed irregularly in the radial and/or axial direction in order to ensure a joint engagement,

-the envelope volume is less than or equal to the cartridge volume.

A sheathing core with a circular cross section, which has a cross section exactly equal to the cross section of the sheathing core, is therefore provided with at least one core sheathing which extends over its entire length concentrically to the longitudinal axis of the sheathing core, and has a higher bending breaking tension than a monolithic core.

At the same time, the composition and/or the surface of the core coating is configured in such a way that a better adhesion is achieved when the core is glued into the wood container.

It is advantageous if both the cross section of the core cladding and the cross section of the core are designed to be circular, since otherwise, at the edges, a notch stress is formed which cannot be ignored and which leads to a reduction in the bending strength.

Another advantage of the invention is that the core of the pen can be completely improved or adjusted to specific properties such as wear resistance or slip properties, since the stability is established mainly by the cladding material.

Drawings

The cartridge according to the invention is further described below with reference to several figures.

Here, it is shown that:

FIG. 1: a section of a cladded cartridge according to the present invention having a cartridge cladding;

FIG. 2: cross section of a cartridge according to figure 1;

FIG. 3: a refill according to the invention, which is glued into the wood;

FIG. 4: a cartridge according to the invention with two cartridge envelopes.

Detailed Description

Fig. 1 shows a longitudinal section of a cladding core 1 with a core cladding 2, wherein in this embodiment the core cladding 2 is formed concentrically around the longitudinal axis of a core 3.

Fig. 2 shows a cartridge or cladding cartridge 1 according to fig. 1 in cross section. The concentric design of the cartridge 1 is clearly visible in this view. In this embodiment, the core 3 is surrounded by a core cladding 2.

Fig. 3 shows a sheathing lead 1 consisting of a lead core 3 and a lead sheathing 2, which has a housing 4 consisting of two small wood pieces 41, the sheathing lead 1 being glued into grooves in the small wood pieces 41, as is known, for example, from typical pencils or crayons. The pencil accommodated in the wood has a hexagonal outer contour in this embodiment.

Fig. 4 shows a further embodiment of a sheathing refill 1' according to the invention. The core 3 is surrounded in this embodiment by two core coatings 2 and 2'. The structure shown here is also a concentric system.

In these figures, the embodiment variants of a cartridge with three or more cartridge envelopes are not shown. These coatings may be, for example, chemically or ceramic bonded coatings. The order in which the lead coatings are arranged can be freely selected. It is only important here that the at least one core cladding has a higher strength than the core.

It is understood that the increased stability of the cartridge against fracture is achieved by the inventive configuration of the cartridge. Furthermore, the lead is not easily broken during the production process, which leads to a low rejection rate of the lead. For the user of a writing instrument with a writing instrument according to the invention, it is advantageous that the writing tip can be loaded with a higher writing force than a one-piece writing tip with a uniformly configured cross section, i.e. without problems with high stresses, which are typical, for example, when children learn writing.

In order to illustrate the invention more specifically, the following exemplary formulations for the core and the core cladding are described.

Examples of pencil-coating lead formulations

A pen core: hardness HB

Graphite 65% by weight

Clay 35% by weight

A pen core cladding layer: hardness H

Graphite 60% by weight

Clay 40% by weight

In the formulation example, one of the graphite cartridges, which has a hardness of HB, is surrounded by a hard coating (hardness H). Not only the core but also the cladding consists of a material that releases color.

From the table below, it can be seen how the strength of the cladded lead changes relative to the strength of the overall lead. The area ratio of the cladding area to the refill area is equal to 1.

Strength of	Unit of	Integral pen core	Cladded pen core	Strength improvement
					Bending rupture strength of pen core	MPa	84	113	+36％
Breaking strength of tip of pen	N	30	50	+66％

The strength is improved by increasing the bending rupture stress. Generally, the increase in the tip rupture strength is achieved by the increase in the bending rupture strength of the pen core and the improved adhesion of the clad material due to its optimal chemical mechanism.

Formulation example of color pen cladding refill

A pen core: yellow colour

Organic pigment 7% by weight

Inorganic pigment 15% by weight

8% by weight of lubricant

Binder (Binder) 5% by weight

Rest of filler

A pen core cladding layer: white colour

Inorganic pigment 20% by weight

15% by weight of lubricant

Binder 9% by weight

Rest of filler

The strength changes of the bending fracture and the tip fracture are shown in the following table.

Strength of	Core/cladding area ratio	Integral pen core	Cladded pen core	Strength improvement
					Bending breaking strength unit MPA of pen core	1.44	46	52	+13％
Breaking strength unit N of pen tip	1.44	17	27	+59％

In this case, it can also be seen that a further increase in stability is achieved by using an optimized or adapted coating formulation and by improving the adhesion of the core in the wood. In this embodiment of the cladding core according to the invention, the yellow core is surrounded by a white core cladding, which can be seen as a white ring in the sharpened state. If such a refill is accommodated in the wood, the transition from the wood to the yellow refill core through the white ring can be seen in the tip region. It is advantageous if information is stored on the color of the ring, i.e. the cladding material, which information provides the user with information, for example, about the manufacturer, the hardness, the cartridge diameter or the like.

In each of the illustrated cases, it is shown that no reduction in the quality of the strokes occurs.

Such sheath cartridges are produced, for example, by the Coextrusion process (Coextrusion).

The invention relates to a refill for a writing, drawing or painting instrument, comprising a refill core which releases color in the direction of the longitudinal axis and at least one refill coating, wherein the at least one refill coating surrounds the refill core when viewed in cross section of the refill, wherein the refill coating and the refill core are held immovably relative to one another and the at least one refill coating has a higher bending strength than the refill core. The core cladding forming a core casing, viewed in cross section of the core, has a higher bending strength than the core. The core cladding or the core claddings are formed concentrically opposite to each other or around the core, wherein at least one of the core claddings has a different color than the core. For example, the at least one core coating is formed in white. In this case, the at least one core cladding can be embodied with or without color. The material composition of the core and the material composition of the core cladding can be configured differently. Furthermore, the core and the at least one core coating are made of materials of different particle size distributions and/or particle fineness. The core cladding can have a cross-sectional area, seen in the cross-section of the core, which is smaller than or the same as the core.

The outer diameter of the core, as seen in the cross-section of the core, engages (Verzahnen) and/or is otherwise mechanically fixed with the inner diameter of the core cladding immediately adjacent to the core.

A boundary line or a boundary plane is formed between the core cladding and the core, wherein the boundary line is preferably irregularly formed in the radial and/or axial direction.

The core of the cartridge may have a ceramic binder (Bindung) or an organic binder. Likewise, the at least one core cladding may have a ceramic bond or an organic bond. The at least one cartridge cladding may be under compressive stress.

Reference to the list of reference numbers:

1. 1' cladding refill

1. 2' refill cladding

3-pen refill core

4 outer cover

41 Small wood sheet

Claims (13)

1. Refill for writing, drawing and painting instruments, comprising a color-releasing refill core (3) and at least one color-releasing refill cladding (2, 2 ') in the direction of the longitudinal axis, wherein the at least one refill cladding (2, 2 ') surrounds the refill core (3) as seen in cross section of the refill (1, 1 '), and the refill cladding (2, 2 ') and the refill core (3) are coextruded and thus immovably fixed to one another, characterized in that the at least one refill cladding (2, 2 ') has a higher bending strength than the refill core (3).

2. A refill according to claim 1, wherein said refill sheath (2, 2 ') constituting a refill casing has a higher bending rupture strength than said refill core (3) seen in a cross-section of the refill (1, 1').

3. A refill according to claim 1 or 2, wherein said at least one refill envelope (2, 2') is concentrically arranged with respect to said refill core (3).

4. A refill according to claim 1 or 2, wherein at least one refill cladding (2, 2') has a different colour from the refill core (3).

5. A refill according to claim 1 or 2, wherein said at least one refill envelope (2, 2') is configured in white.

6. A refill according to claim 1 or 2, wherein the material composition of the refill core (3) is configured differently from the material composition of the refill cladding (2, 2').

7. A refill according to claim 1 or 2, wherein the refill core (3) and the at least one refill coating (2, 2') consist of materials of different particle size distribution and/or materials of different particle fineness.

8. A refill according to claim 1 or 2, wherein the refill cladding (2, 2 ') has a smaller or equal cross-sectional area than the refill core (3) seen in a cross-section of the refill (1, 1').

9. A refill according to claim 1 or 2, wherein the outer diameter of the refill core (3) is mechanically fixed in snap-fit with the inner diameter of a refill cladding (2, 2 ') adjacent to the refill core (3) as seen in a cross-section of the refill (1, 1').

10. A refill according to claim 1 or 2, wherein a boundary line or an interface is formed between the refill cladding (2, 2') and the refill core (3); the dividing line is irregularly shaped in the radial and/or axial direction.

11. A refill according to claim 1 or 2, wherein the refill core (3) has a ceramic binder or an organic binder.

12. A cartridge according to claim 1 or 2, characterized in that said at least one cartridge cladding (2, 2') has a ceramic or organic binder.

13. A refill according to claim 1 or 2, wherein said at least one refill envelope (2, 2') is under compressive stress.