Abstract:
A process for producing an object made from plastic material with a mesh structure, wherein the mesh structure is deformed in at least one defined area, in such a manner that the original mesh structure of the area is eliminated and an essentially continuous structure and information can be introduced in this area.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 09/276,284 filed on Mar. 25, 1999, now abandoned, which claims priority under 35 USC §119 of German Patent Application No. 19813619.6 filed on Mar. 27, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The invention relates to a method for producing an object made from a plastic material with a mesh structure and to the object produced therefrom. 
     2. Prior Art 
     Objects made from plastic material are used to protect sensitive components that are transported, for example, on pallets or in containers. These objects, which are often formed as covers, mats or sleeves, can be provided as intermediate layers or as sheaths between layers of components. A typical object can comprise a lattice structure that has been produced by extrusion and is formed from intersecting strands, the strands running perpendicular or with an inclination with respect to one another at the intersection points. The strands are usually arranged in two preferably parallel planes, in such a manner that in each plane the strands are aligned parallel to one another. 
     Thus, for example, bought-in parts for the automotive industry are conveyed in layers inside containers, covers or mats made from plastic with a mesh structure being provided between each of the individual layers. Notes that are easily legible and are simple to fix to the object are advantageous in order to be able to identify the covered parts or the properties of the object that forms the cover, mat or sleeve. 
     BRIEF SUMMARY OF THE INVENTION 
     The invention is a method for producing an object, in particular a cover, mat or sleeve, made from a plastic having a mesh structure which incorporates an area for identification information. The object is produced from a plastic mesh structure by forming a generally continuous surface over at least a defined portion of the mesh structure onto which identification or other information can be placed, by, for example, imprints, writing, stickers, or the like. 
     The object according to the invention is distinguished by at least one surface that is an integral part of the mesh structure. In the area of the surface, which is at a predefined location on the mesh structure, the original mesh structure is eliminated and, instead, an essentially continuous surface is present. Information, notes or the like can be arranged on this surface and can be used, for example, to identify or explain the components covered by the object. It is possible to apply an adhesive, to print on the surface, to stamp the surface and/or to form symbols in the surface. Symbols may also be introduced into the surface by means of cutouts or the like. The surface, or each surface if more than one surface is created, in which area, according to the invention, the mesh structure of the object has been eliminated, can also be referred to as the identification surface. Moreover, it is conceivable for the surface to serve as a support for or to receive any desired parts. 
     The method for producing the object is distinguished by the fact that the mesh structure of the object to be produced is deformed in the area of at least one defined surface. This deformation is so extensive that the original mesh structure in the area of the defined surface in question is eliminated and is essentially replaced by a continuous surface. Therefore, the mesh structure material that is present is the area of the surface to be produced is deformed in such a manner that it forms the surface in question. Specifically, the mesh structure is compressed, generally in the presence of heat, such that the strands of the mesh deform into the interstices between mesh strands, ultimately touching and binding with adjacent strands to form a continuous surface. Therefore, according to the method of the invention, no additional material is required to form the surface or even a plurality of surfaces. 
     The surface preferably is formed from the mesh structure by means of deformation, in particular as a result of pressure and/or heat. This means that the material forming the mesh structure is heated or compressed until a continuous surface is formed. The definition “continuous surface” does not mean that a completely smooth and homogeneous surface structure need be present. It is acceptable if some interstices remain in the continuous surface, even if the surface is not completely continuous. The important factor is that the surface formed be sufficient to serve as a base or support for the information, symbols, writing, stickers, or other items that are to be applied or introduced. If the purpose of the surface requires, it should be possible for an adhesive to be able to adhere sufficiently firmly to this surface. This may be possible even if the apertures present in the mesh structure are not completely closed. 
     The surface formed generally and preferably is sufficiently less high or thick thinner) than the remaining mesh structure. The height of the latter mesh structure corresponds to the thickness of the two superposed strand layers. By contrast, the material that has been displaced into the spaces in the mesh structure during the formation of the continuous surface means that the surface is significantly less thick. The surface may be planar or deformed or present deformations. 
     The invention also may be used for sleeves or pockets formed from a mesh structure, for example for protecting rotationally symmetrical or rod-like objects, such as shafts, pins or the like. Sleeves of this nature also may be applied to a pin, which serves as a support, in order to form the identification surface using a ram that has appropriate contours. 
     Further features of the invention will become more apparent to those of ordinary skill in the art from the remaining description and form the claims. Exemplary embodiments of the invention are explained below with reference to the drawings in which like reference numerals represent like components throughout the several views. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a plan view of a cover with an identification surface according to the invention. 
     FIG. 2 shows an enlarged plan view of the cover in accordance with FIG.  1 . 
     FIG. 3 shows an enlarged cross section through a cover in accordance with FIG. 1 after an identification surface has been produced using a ram-like tool. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Typical plastic mesh structures used in the transportation of articles, particularly sensitive or fragile articles have an inherent degree of elasticity. Part of the elasticity may come from the plastic material of manufacture and at least part of the elasticity comes from the mesh structure itself. Specifically, a mesh structure comprising relatively thin strands and open spaces (such as the typical grid mesh structure) exhibits elasticity in both the X- and Y-directions along the plane of the mesh structure due to the deforming of the grid. 
     The present method results the formation of a thin walled, continuous surface that retains at least a portion of the elasticity of the original mesh structure. In the past, one of ordinary skill in the relevant art would refrain from forming a continuous surface by stamping the mesh structure because it was not expected that the available material of the mesh structure is sufficient for this purpose. Because packing materials generally have a mesh structure, it generally was expected that the stamping of the packing with a heated ram would disrupt the mesh surface and render it useless for packing. However, in the present invention it has been found that this is not the case, and the resultant thin-walled continuous surface retains at least a portion of the original elasticity of the original mesh structure. This resultant formation from the claimed method is a nonobvious and unexpected to those of ordinary skill in the art. 
     The method generally results in the formation of a thin-walled, continuous surface using the material of the mesh structure that has the advantage of retaining its elastic structure. This retention of elasticity in the continuous surface is important because mesh structures with elasticity are generally employed for packing or for protecting sensitive objects. The elasticity of the packing material allows for improved protection of packed objects, greater ease of use, and less chance of ripping or tearing of the mesh structure due to the formation of the thin-walled continuous surface. 
     The present invention provides a method for introducing information onto a mesh structure, used for example to protect sensitive equipment, which does not involve the complete melting of the structure&#39;s material to convey information. More specifically, the present invention allows one to introduce information onto a formed surface of mesh packing material by mean of stamping with a heated ram; the information can be introduced stamping the surface of the material. For example, the present invention allows the mesh structure to be directly labeled and replaces the need for stickers and tags for such labeling. Thus, additional material is not need to for the labeling of the units and there is a reduced risk the label will not be on the unit. Further, the present invention allows for the information to be introduced without a disruption to the surface of the mesh material, i.e. allows the mesh material remains continuous. Very specifically, the method allows the formation of a base where such information can be applied. 
     The present invention is distinct from common embossing methods. Although the present method does involve stamping directly onto a lattice, one advantage of the present method is that it allows the user to create a base onto which information can be placed. Further, the user does not need to expend many resources creating the defined area because it is just a stamp. 
     The method generally results in the formation of a thin-walled, continuous surface using the material of the mesh structure, and retaining at least some of the elastic structure of the mesh material. This retention of elasticity in the continuous surface is important, and unexpected, because mesh structures are generally employed for packing or for protecting sensitive objects. For this reason, there is a need for a high degree of flexibility and elasticity. 
     Referring now to the FIGS., an approximately rectangular cover  10  is used to cover and protect mechanical components. In an example, such a cover  10  can be transported in containers or on pallets. By way of example, the cover  10  is laid on a layer of components in a container before a further layer of components is added. 
     The cover  10  preferably can be produced from a thermoplastic material, specifically from two layers  12 ,  13  that are joined together in the region of intersection points  11 , with each layer  12 ,  13  comprising mutually parallel strands  14 ,  15 . These strands are formed by extrusion and, in the area of the intersection points  11 , adhere to the strands of the other respective layer. 
     An identification surface  16  or a surface that is provided as a support or to be laid on top is formed in the cover  10 . In the present illustrative example shown in the FIGS., this surface is virtually circular, but the surface can have any desired form, such as oval, square, triangular or other geometric or non-geometric shapes. In general, the identification surface may be formed by any suitable method, with heat or compression or a combination of heat and compression being preferred. 
     In the illustrative example, the identification surface  16  is formed by a heated round ram  17  that is positioned with a slight pressure on a defined portion of the cover  10  until the mesh structure formed by the strands  14 ,  15  has been largely removed (that is reformed from strands into a generally flat continuous surface) and said identification surface  16  has been formed. The pressure of the ram  17  on the two layers  12 ,  13  eliminates (that is reforms) the mesh structure by displacing the material of the strands  14 ,  15  into the spaces  18  between the strands  14 ,  15  that are otherwise present. In this way, the continuous surface  16  is formed. The ram surface  24  preferably is of planar design, as is the surface  16  formed. Other forms, for example with recesses, depressions and projections, are possible. 
     The ram  17  interacts with a support  19  that acts as a mating die. This mating die is of corresponding design to the ram, and preferably is without recesses, depressions or the like. As a result, an underside  20  of the compressed section  21  of the identification surface  16  being formed ends approximately flush with the bottom layer  13 . In contrast, a top side  22  of the section  21  is offset inwardly with respect to the upper layer  12 . Depending on the mesh width of the mesh structure, a shoulder  23  may appear in the direction of the underside  20  and as a circumferential rim of the compressed section  21 . 
     The heat and/or pressure applied to the ram  17  are dependent on the material of the cover  10  and on the desired density or the desired structure of the identification surface  16 . A thermoplastic can be melted and transformed from a mesh structure to a continuous identification surface in a simple manner and/or in a short time. A particular advantage of this process is that there is no need to add any material. All that happens is that the existing material is reshaped. 
     In a separate operation or during the reshaping of the mesh structure, the identification surface  16  can be provided with a marking, for example with information about the components that are to be protected by the cover  10 . The ram  17  may, for example, stamp the appropriate information into the identification surface  16  during the reshaping operation. A possible application shown in FIGS. 1 and 2 is the provision of an identification number. 
     The marking is preferably applied to the inwardly offset top side  22 . This provides additional protection for the marking against damage, for example from further large-area, heavy components that have been placed on top of the identification surface  16  specifically and the cover  10  generally. Information also can be applied to the identification surface  16  or the top side  22  or underside  20  subsequently, for example by stamping, printing or adhesive bonding. In each case, applying this information is easier than if the mesh structure alone were to be present. 
     In an embodiment that is not shown, a sleeve in the form of a tube, jacket or pocket is provided instead of a cover  10 . This too can be provided with an identification surface  16  by using suitable tools. For example, a sleeve for protecting a shaft can be reshaped so as to form an identification surface  16 , by introducing a mandrel and a ram that acts on the outside, in virtually the same way as the cover  10 . 
     The individual strands  14 ,  15  within each layer  12 ,  13  preferably are at equal distances from one another. For example, in each layer, approximately 10 to 12 plastic strands lie next to one another for every 10 cm (that is, a strand density of 10 to 12 strands per 10 cm has been found to be a suitable density for the mesh structure). The diameter of each of the strands is approximately 0.5 to 5.0 mm, and preferably approximately 1.0 to 3.0 mm. To achieve the mesh structure, the strands  14  of one layer  12  are directed in a transverse or inclined manner with respect to the strands  15  of the other layer  13 , see in particular FIG.  1 . 
     The distance A, as shown in FIG. 3, between adjacent strands  14 ,  15  is approximately 0.5 to 5.0 times the diameter of the strands  14 ,  15 . Thus, for example, for a strand  14 ,  15  having a diameter of 3 mm, the distance A between two adjacent strands lies in the range of 1.5 to 15 mm. Preferably, the distances between adjacent strands  14  and adjacent transverse strands  15  are equal, thus creating a square space  18  bounded by two adjacent strands  14  and two adjacent transverse strands  15 . As a result, the dimensions of the spaces  18  are in the range of approximately 1.5×1.5 mm to 15×15 mm, and preferably approximately 3×3 to 5×5 mm. Typically, after being compressed, the wall thickness of the identification surface  16  of the compressed section  21  is in the range of 0.3 to 1.0 mm. 
     The above detailed description of the preferred embodiments and the appended figures are for illustrative purposes only and are not intended to limit the scope and spirit of the invention, and its equivalents, as defined by the appended claims. One skilled in the art will recognize that many variations can be made to the invention disclosed in this specification without departing from the scope and spirit of the invention.