DE202005001430U1 - Lead for writing, drawing and colouring devices has colour-producing core and outer casing, whereby casing encloses core viewed in cross-section of lead and casing and core are movable in relation to one another - Google Patents

Abstract

The lead (1) for writing, drawing and colouring devices has a colour-producing core and an outer casing, whereby the casing encloses the core viewed in cross-section of the lead and the casing and core are movable in relation to one another. The casing (2) has a higher bending strength than the core (3). The casing is located concentrically to the core. The casing has a different colour to the core.

Description

The Invention relates to a mine for Write, draw or painting devices according to the preamble of the main claim.

mines for writing, drawing and / or painting are known in principle.

Known Writing or painting leads are usually called solid core mines or Chalks formed and fixed or displaceable within a shell supported.

was standing The technique is one-piece, homogeneously formed mines, which a compromise of desired Writing properties, which among other things adjustable over the mine hardness are and for to represent the application necessary mine strength.

Becomes a minimum mine strength falls below, so usually remains only the possibility to increase the mine cross section to in this way to increase the load capacity of the mine.

It is to be regarded as disadvantageous that an enlargement of the Mine diameter and thus used mine material, to a significant increase in the cost of the mine. Next is this considered to be disadvantageous that an enlarged mine diameter negative Effects on press speed, drying time and the heat energy requirement Has.

Out DE-GM 12 01 339 and the patent application DE-H 142 675 are multicolored Mines known, with different colored mines stored in each other are. With such mines or pencils can multicolored smears be achieved.

adversely in the described mines and pens made therewith, it is that despite the arrangement of different colored sleeves into each other no increase in the Bending strength against a monochrome mine is achieved, which causes the pens as known tend to break quickly.

Next are from the DE 43 32 582 A1 fired pencil leads and the process for their preparation known. In such mines, a lead mass is compressed such that between the central portion and the outer peripheral portion one or more layers are radially spaced from the outer peripheral portion in which the filler is oriented in concentric tubular shape, the filler in The other areas of the mine is arbitrarily or radially oriented.

adversely is that this is a complex manufacturing process. An example of this is that in this process by the platelet-shaped additives very high shear energies occur in the extruder, which greatly reduces the press performance. One Another major disadvantage is that the increase in strength which is done in this way, not high enough to manufacture justified effort. The used or used Mine material is over the entire mine cross-section identical, which is a high consumption At high quality mine mass, which in itself only in the writing area or Peak area needed would, entails.

task The invention therefore is a fired or unburned mine to write, to draw or to paint, the said Disadvantages does not have and which in particular a higher load capacity against external forces, without causing the used mine formula of the color-releasing material, changed the so-called mine core becomes. The task is the vulnerability To reduce the mine against breakage due to high writing as well as by sharp points.

These Task is with the characterizing features according to claim 1 solved. Advantageous embodiments result from the subordinate Claims.

Mines for writing, drawing or painting are, on the one hand, mines that are firmly inserted into wood or other sharpenable materials and, on the other, mines that are slidably supported in a rigid casing. Examples of this are wooden pencils and colored pencils, fine mines for mechani crayons, so-called mechanical pencils and pencils for droppings. The mines usually have outside diameters in the range of about 0.3 mm to 6 mm.

at The lead or lead minerals can be burnt as well Trade unfired mines.

Further the invention can also be used in wax-based millcraps.

The Asked object is achieved by the inventive mines are formed such that they have at least one mine jacket, which is essentially concentric around the mine core or the central axis of the mine extends.

Of the Min core may have a composition of the prior art.

Of the Mine mantle that surrounds the mine core acts like a support mantle. This support coat points to the stability to increase the mine against breakage, an increased Strength on.

It it is possible the support jacket, which surrounds the mine core, to make colored, with the used Colors an information about For example, manufacturer, hardness, Mine type or line weight may contain. Through a color differentiation of the mine jacket from the mine core, can be a brand specific and visually perceptible Be created for the consumer or user Existence of a higher quality Mine already visually at the sharpened mine by a trained color ring on the conical surface signaled.

exemplary be cited that by the sheath of a mine core, which according to the state of Technique made with known mine material compared with a mine according to the prior art without sheathing, at same overall cross section, both graphite and color mines, the Rebound fracture strength of the mines increases significantly by 20 to 60%.

at Such a high increase in the bending strength of the coated Mines, could also the total cross-section of the jacketed mines can be reduced, without compromising on strength to lose unencumbered state-of-the-art refills. A Cost savings are the direct result.

The Manufacturing costs can by using cheaper Sheath raw materials are significantly reduced.

It has also shown that by special sheaths fluctuations in quality and manufacturing tolerance of the core material leveled or balanced can be.

The Composition of the material for The mantle zone can usually be made from less expensive raw materials be as accurate to the desired writing properties set core of the mine. For example, clay could be used instead of graphite be used. The mine jacket serves with normal handling a wooden writing, drawing or painting device only as a support jacket and is also unused by the user with written off Minenkern by the user abgespitzt.

Advantageous with such a design of the mine it is that, despite the Increasing the strength of the jacket material surrounding the mine core no impairment the writing quality occurs because the mine core have the same composition can, like a manufactured to date full lead according to the prior art. On the contrary, the mine core in coated mines what the As far as writing properties are concerned, they are significantly more optimized since a substantial strength entry takes place through the jacket.

Of the Mine cross-section can be circular, oval, drei-, six-, rectangular or designed almost arbitrarily designed be. The circular shape is preferred.

One or several mine coats can be arranged concentrically around the mine core.

A concentric arrangement ensures that the mine, regardless of the writing position and thus the pressure load in all orientations has the same strength and writing properties.

If there are several mine coats or mantle zones, the individual coats can be different Colors and / or compositions.

• – eine gleiche oder ähnliche Plastizität wie der Minenkern aufweisen,
• – das Strömungsverhalten des Mantelmaterials annähernd dem des Kernmaterials entsprechen,
• – das Mantelmaterial eine höhere Biegebruchfestigkeit als das Kernmaterial aufweisen,
• – das Schwindverhalten des Mantels dem Kernmaterial angepasst sein, um eine Rissbildung bei dem Trocknungs- und Brennvorgang zu vermeiden,
• – die Trennlinie oder Grenzfläche zwischen Mantelzone und Schreibkern vorzugsweise radial und/oder axial irregulär ausgebildet sein, um eine Gefügeverzahnung zu gewährleisten,
• – das Mantelvolumen kleiner oder gleich dem Kernvolumen sein.

In order to produce a sheath mine of high quality, the following boundary conditions should be fulfilled. Here, the mine jacket of an inventively designed mine

• Have the same or similar plasticity as the mine core,
• The flow behavior of the jacket material approximately corresponds to that of the core material,
• The jacket material has a higher bending strength than the core material,
• The shrinkage behavior of the jacket is adapted to the core material in order to avoid cracking during the drying and firing process,
• The dividing line or boundary surface between the jacket zone and the writing core may be designed to be radially and / or axially irregular in order to ensure structural toothing,
• - The shell volume be less than or equal to the core volume.

So has a jacket with a circular cross section, which with at least one over the entire length concentric with its longitudinal axis extending mine jacket, compared to a full mine, their cross-sectional area exactly the same size Cross sectional area the sheath mine selected will, a higher Bending stress on.

simultaneously For example, the composition and / or the surface of the mine jacket may be such be designed that when gluing the mine into a wooden frame a better bonding is achieved.

It It has been shown that it is beneficial if both the cross section the mine jacket as well as the cross section of the mine core round are, as otherwise not inconspicuous notches on edges, which result in a reduction of the bending strength.

One Another advantage of the invention is that the mine core completely on special properties such as abrasion behavior or sliding properties can be improved or adjusted, since the stability is predominantly due to the jacket material is built up.

Based In some figures, the mine according to the invention will be described in more detail below.

in this connection demonstrate:

1 : the section through a casing mine according to the invention with a mine casing;

2 : the cross section of the mine according to 1 ;

3 : a mine according to the invention, which is glued in wood;

4 a mine according to the invention with two mine jackets;

1 shows a sheath mine 1 with a mine coat 2 in longitudinal section, which in this embodiment, the mine jacket 2 concentric about the longitudinal axis of the mine core 3 is trained.

2 shows the mine or mine 1 according to 1 in cross section.

In this view is the concentric construction of the mine 1 clearly. In this embodiment, the mine core is 3 from a mine coat 2 surround.

3 shows a sheath mine 1 , consisting of mine core 3 and mine coat 2 , with one of two wooden boards 41 existing serving 4 , where the mantle mine 1 into the grooves of the wooden boards 41 is glued, as is known from a classic pencil or colored pencil. The wooded pin has in this embodiment a hexagonal outer contour.

4 shows a further embodiment of a sheath mine according to the invention 1' , The mine core 3 is in this version of two mine-jackets 2 and 2 ' surround. The construction shown here is also a concentric system.

In not shown in the figures are embodiments of mines, which three or more mine coats exhibit. At the coats it may be, for example, chemically or ceramically bound coats. In which order the mine coats are arranged, is freely selectable. It is important only that at least one mine jacket a higher strength as the mine core has.

It can be stated that by the embodiment of the invention the mine an increase stability the mine takes place against breakage. The mine is already already less prone to breakage in the manufacturing process, resulting in a lower reject rate entails.

For the user a writing instrument with the mine according to the invention It is advantageous that the lead tip with a higher typist, Compared to a full mine with uniform cross-sectional area, loadable is that so higher Printed forces like that for the write-learning behavior in children is typical, easily tolerated become.

In order to illustrate the invention even more clearly, formula compositions for mine core and mine jacket are given below by way of example. Recipe example of a lead sheath mine mine core: hardness HB graphite 65% by weight volume 35% by weight Mine jacket: Hardness H graphite 60% by weight volume 40% by weight

In This recipe example is a soft graphite core hardness HB with a harder one Coat (hardness H) surround. Both core and mantle consist of a dye-giving Material.

Out The following table shows how the strength the mine opposite changed the full mine. The area ratio of Sheath to core surface is equal to 1.

There is an increase in strength by increasing the bending stress. In general, there is an increase in the peak breaking strength, an increase in the bending strength of the lead and an improved bonding of the shell material due to its optimized chemistry. Recipe example of a multi-colored mine mine core: yellow organic pigment 7% by weight inorganic pigment 15% by weight lubricant 8% by weight binder 5% by weight fillers rest Mine coat: white inorganic pigment 20% by weight lubricant 15% by weight binder 9% by weight fillers rest

In The following table shows the strength changes documented in the bending and tip break.

Also In this example it can be seen that a further increase in the stability through improved bonding of the mine in the wood through an optimized or adapted shell formulation takes place.

In this embodiment a casing mine according to the invention, in which a yellow mine-core is surrounded by a white mine-mantle, is in the sharpened state of the coat as a white ring recognizable. If such a mine is set in wood, then it is in the top area a transition from the wood, over a white one Ring to the yellow mine core recognizable. It can be advantageous if the color of the ring, ie the jacket material information which informs the user about, for example, manufacturer, degree of hardness, Mine diameter or the like supplies.

In each of the cases described has been shown to decrease the quality of the smear not happened.

A Such sheath mine can be prepared for example by coextrusion become.

The Invention relates to a mine for Writing, drawing and painting equipment, which in the direction of the longitudinal axis a color-releasing mine core and at least one mine coat , wherein the at least one mine jacket the mines core in Cross section of the mine seen surrounds and being mine shell and mine core are secured against displacement and the at least one Mine coat a higher Has bending strength as the core of the mine.

Of the Mine jacket, which forms a mine envelope when viewed in the cross-section of the mine, has a higher one Flexural strength as the minenkern on. The mine coat or the mine coats are arranged concentrically to or around the core of the mine, at least a mine coat has a different color than the mine core. For example the at least one mine jacket can be formed in white color.

in this connection the at least one lead coat may be color releasing or non-releasing be educated.

The Material composition of the mine core and a material composition the mine jacket can hereby be designed differently.

moreover can the mine core and the min. A mine coat of materials different particle size distribution and / or grain fineness.

in the Cross-section of the mine seen, the mine jacket can be a smaller or the same size Cross sectional area have like the mine core.

in the Cross-section of the mines seen may have an outer diameter of the mine core with an inner diameter of the mine shell adjacent to the mine core interlocked and / or otherwise mechanically anchored.

A Dividing line or an interface is formed between the mine jacket and the mine core, wherein the dividing line preferably formed radially and / or axially irregular is.

Of the Mine core can be a ceramic tie or an organic tie exhibit. Likewise, the at least one mine jacket a ceramic Having binding or an organic bond. The at least one Mine jacket can be under compressive stresses.

1, 1'

coat mine

2, 2 '

mine cloak

3

lead core

4

wrapping

41

Holzbrettchen

Claims (14)

Mine for writing, drawing and painting equipment, which in the direction of the longitudinal axis of a color-releasing mine core and at least a mine jacket, wherein the at least one mine jacket surrounds the mine core seen in the cross-section of the mine and mine mine and mine core are held each other secure against displacement, characterized in that the at least one mine casing ( 2 . 2 ' ) has a higher bending strength than the core ( 3 ) having. Mine according to claim 1, characterized in that the mine casing ( 2 . 2 ' ), which in cross-section of the mine ( 1 . 1' ) forms a mine envelope, a higher bending strength than the mine core ( 3 ) having. Mine according to one of claims 1 or 2, characterized in that the mine casing ( 2 . 2 ' ) or the mine coats concentric to the mine core ( 3 ) is arranged or are. Mine according to claims 1 to 3, characterized in that at least one mine casing ( 2 . 2 ' ) has a different color than the mine core ( 3 ). Mine according to one of the preceding claims, characterized in that the at least one mine casing ( 2 . 2 ' ) is formed in white color. Mine according to one of the preceding claims, characterized in that the at least one mine casing ( 2 . 2 ' ) is color-donating or non-color-donating. Mine according to one of the preceding claims, characterized in that a material composition of the mine core ( 3 ) and a material composition of the mine jacket ( 2 . 2 ' ) are formed differently. Mine according to one of the preceding claims, characterized in that the mine core ( 3 ) and the at least one mine jacket ( 2 . 2 ' ) are formed from materials of different particle size distribution and / or particle size. Mine according to one of the preceding claims, characterized in that in the cross-section of the mine ( 1 . 1' ), the mine jacket ( 2 . 2 ' ) has a smaller or the same cross-sectional area as the mine core ( 3 ). Mine according to one of the preceding claims, characterized in that in the cross-section of the mines ( 1 . 1' ) seen an outer diameter of the mine core ( 3 ) with an inside diameter of the Mine core ( 3 ) adjacent mine mantle ( 2 . 2 ' ) toothed and / or otherwise mechanically anchored. Mine according to one of the preceding claims, characterized in that a dividing line or an interface between the mine casing ( 2 . 2 ' ) and the Minenkern ( 3 ) is formed and that the dividing line is preferably formed radially and / or axially irregular. Mine according to one of the preceding claims, characterized in that the mine core ( 3 ) has a ceramic bond or an organic bond. Mine according to one of the preceding claims, characterized in that the at least one mine casing ( 2 . 2 ' ) has a ceramic bond or an organic bond. Mine according to one of the preceding claims, characterized in that the at least one mine casing ( 2 . 2 ' ) is under compressive stresses.