Patent Application
20120048131
This application claims the priority, under 35 U.S.C. ยง119, of German application DE 10 2010 036 011.2, filed Aug. 31, 2010; the prior application is herewith incorporated by reference in its entirety.
The invention relates to a tool for a rotary embossing device for embossing flat, sheet-shaped material. The tool has two rotating embossing tools including a male embossing tool and a female embossing tool for creating the embossing. The invention further relates to a folder gluer having a Braille embossing device.
Folding boxes are packaging materials made of cardboard or corrugated board or, to a more limited extent, of plastics. At one or more locations, glue is applied to the material during the folding operation as required for the individual construction of the folding box. As a rule, a folding box is made out of a blank that has been cut out in a diecutting machine. At least one edge of the blank must be glued. The folded boxes exit the folder gluer in a flat state. The folding box is then erected and filled either in a machine or in a manual process.
In addition to the folding operations required to manufacture the folding boxes, additional crease lines are formed or prefolded in the folder gluer in preparation of subsequent production steps. These crease lines facilitate the erection and filling of the box.
If the folding boxes are intended as packaging for pharmaceutical products, the law requires the name of the product or medicine to be applied to the folding box in Braille letters for the blind (for instance in an embossing process). Moreover, Braille letters or other embossing need to be applied to many blister packs or blister cards.
In the prior art, Braille letters may be embossed during the diecutting operation in the diecutting machine when the blanks are being produced. However, this is a laborious process because one sheet contains a number of blanks and for each blank a pair of tools consisting of a female and a male tool needs to be provided. Alternatively, the Braille letters may be created in a rotary embossing device that has two rotating embossing tools and may for instance be part of a folder gluer. Such rotary embossing tools are known to have a common drive for both rotary tools. To create the embossing in the correct location on the blank or blister pack, the rotary tools need to be synchronized relative to the folding box blank. In particular if the embossing to be made in the folding box blank are Braille characters, the synchronization must be made with great accuracy. Due to the inertia of the female and male embossing tools and the rotary drive the required degree of synchronization accuracy is difficult or even impossible to achieve. Another disadvantage is that to improve synchronization, rotary embossing devices are frequently operated in a start/stop mode, i.e. they are stopped and subsequently reaccelerated for synchronization purposes. This aspect has a detrimental effect on the productivity of the rotary embossing device. Another aspect that limits productivity is that the rotary embossing tool cannot be adapted to the size of the product to be processed.
Such a rotary embossing device for a folder gluer is known from European patent application No. EP 20 36 712 A2.
The known Braille embossing devices generally consist of an upper rotary tool known as the male Braille tool, and a lower rotary embossing tool, known as the female Braille tool. On its embossing side, the male Braille tool has a predetermined number of raised Braille embossing dots. The female Braille tool generally has the maximum number of Braille dot recesses and can thus be universally used. The number of recesses depends on whether the Braille letters are written in the common six-dot notation or in the eight-dot notation.
The production of packaging for pharmaceuticals in particular requires a multitude of different Braille imprints. For each new job to be produced, the male Braille tool needs to be modified. Thus a large number of male Braille tools needs to be stored in a tool storeroom.
To reduce storage requirements, German Utility Model No. DE 20 2008 017 133 U1 proposes to keep the roller body unmodified and only to change the actual tool. The tool is held against the circumferential surface of the roller body by magnets.
Another known Braille embossing method is to provide sheet metal strips as the male tool and to screw the sheet metal strips onto the male tool cylinder. The attachment holes that are required to fix the sheet metal strip to the cylinder reduce the maximum circumferential surface that can be used for embossing such as Braille letters. In addition, the strips are difficult to mount. If a strip is mounted in the wrong way, it may assume a helical shape, which is detrimental to the quality of the imprint. Moreover, the embossing tool on the strip of sheet metal is created when the strip is in a flattened position. Yet when it is used in the embossing operation, the strip is wrapped around a circumference of a cylinder and forms an arcuate segment. Errors or distortions in the imprint may be the result. Moreover, there may be a gap between the strip of sheet metal and the male embossing tool cylinder. Such a gap may cause the strip to move up and down and may thus cause premature wear of the female tool. Due to the strict accuracy requirements, this solution is hardly suited for embossing Braille characters. At the high production speeds for instance in a folder gluer (of up to 200,000 boxes/h), the system may get out of balance because the embossing tool only covers part of the circumferential surface. Balancing measures are necessary to counteract this phenomenon.
German Utility Model No. DE 20 2006 005 299 U1 discloses an embossing cylinder or an embossing sleeve arranged on a carrier core for the creation of an embossed structure on a thermoplastic material such as a transparent decorative film. The embossing cylinder or embossing sleeve has individual recesses in the total outer cylinder surface. The material to be embossed is guided through a nip between the embossing cylinder and a smooth counter pressure roller. This device is not suited for creating Braille characters.
It is accordingly an object of the invention to provide a Braille sleeve which overcomes the above-mentioned disadvantages of the prior art methods and devices of this general type, and uses a rotary device for embossing purposes, in particular for embossing Braille characters into flat sheet-shaped material, where the male embossing tool is easily exchangeable.
In accordance with a preferred embodiment of the invention, the tool for a rotary embossing device for embossing flat, sheet-shaped material includes two rotating embossing tools in the form of a male and a female embossing tool. At least the male embossing tool contains a roller body and a seamless, continuous tool sleeve attached thereto. The sleeve has raised embossing dots on its outer circumferential surface. The outer circumferential surface of the female embossing tool has recesses that correspond to the raised embossing dots. In accordance with an advantageous embodiment, the embossing tools are suited for embossing Braille characters. In this case, the female tool may be a universal female Braille tool that has the maximum possible number of Braille recesses per Braille letter. An advantage of these embodiments is that the entire circumferential surface can be used as an embossing surface. Compared to the known strips of sheet metal of the prior art the length of the area that can be used for embossing purposes is increased. In addition, the balancing and distortion problems of the known metal strip solutions are eliminated.
In accordance with further preferred embodiments, the tool sleeve is made of aluminum, steel, magnesium, brass, bronze, titanium, or plastic. Thus the respective advantages of these materials such as hardness, durability, resistance to wear, or low manufacturing cost or rather usability in low-cost manufacturing processes can be exploited. The embossing dots and recesses, respectively, may thus be created in a cost-efficient way in a cupping process from the back or by building up (build-up welding) or by removal of material by milling, etching, or eroding on the outer side. Materials with a suitable surface coating such as a Hard Coat may also be used.
In accordance with a particularly preferred further embodiment the tool sleeve is attached to the roller body by a self-locking cone or a precise fit and/or a pin or a screw in the radial direction or by tension rods. Other attachment options such as pneumatic or hydraulic or mechanical or electrical radial tensioning elements are likewise possible. These attachment means are of simple construction and thus allow a quick exchange of the tool sleeve, thus considerably reducing set-up times.
In accordance with further advantageous embodiments the tool body has a stop to ensure correct positioning of the tool sleeve in the axial direction. Alternatively, the tool sleeve may have a stop that interacts with a groove in the outer region of the roller body. Thus easy and reliable axial positioning of the tool sleeve on the roller body is possible.
In accordance with a particularly advantageous embodiment the stop provided on the tool sleeve and the groove provided in the outer region of the roller body extend at an angle.
In accordance with a further advantageous embodiment the tool sleeve forms the rotor of an electric motor. In addition, the collar of the tool sleeve may be embodied to act as an incremental encoder for the motor.
The tool may advantageously be used in a Braille embossing device in a folder gluer.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a Braille sleeve, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
Referring now to the figures of the drawing in detail and first, particularly, to
In the embodiment shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2010 036 011.2 | Aug 2010 | DE | national |
