Electric heating – Metal heating – By arc
Reexamination Certificate
2002-04-30
2004-04-13
Evans, Geoffrey S. (Department: 1725)
Electric heating
Metal heating
By arc
C131S281000, C219S121770, C359S490020
Reexamination Certificate
active
06720525
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the priority of German Patent Applications Ser. Nos. 101 20 923.1, filed on Apr. 30, 2001 and 101 60 167.0, filed on Dec. 07, 2001. The disclosures of the above German priority applications and of each and every U.S. and foreign patent and patent application mentioned below are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates to a device for producing zones of desired air permeability in the enveloping material of rod-shaped articles, in particular rod-shaped articles in the tobacco-processing industry. The invention relates to a beam guiding arrangement for focussing an energy-rich beam produced by a radiation source onto the enveloping material to form a number of perforation zones, wherein the number of perforation zones corresponds to the number of partial beams. The invention furthermore relates to a multiple beam-generating device that generates a multiple beam from a single beam. The invention also relates to a beam divider, in particular for use in such a device, for dividing a beam generated by a radiation source into at least two partial beams. Finally, the invention relates to a method for producing zones of desired air permeability in the enveloping material of rod-shaped articles, particularly in the tobacco-processing industry. Such a method comprises the steps of focusing an energy-rich beam, produced by a radiation source, onto the enveloping material in order to form perforation zones and to generate a multiple beam from a single beam.
Rod-shaped articles in the tobacco-processing industry in this connection are understood to include all articles provided with a perforation during production or following production. Above all, this refers to filter cigarettes, but can also refer to other types of cigarettes, other rod-shaped smoking articles or filter rods. The enveloping material is understood to include tape used for enveloping tobacco ropes or filter ropes, covering paper tape or sheets and the like, which can be perforated in the form of a material web, ready-to-use sections or as enveloping material for the rod-shaped articles.
Perforating the enveloping material for cigarettes and other rod-shaped smoking articles creates a zone of desired air permeability, through which the smoker suctions in air from the side while smoking. As a result, the shares of nicotine and condensate in the smoke are influenced, which also affects the taste. A laser is preferably used for perforating the enveloping material. The radiation from this laser is guided via an optical beam-guiding device into the respective perforation zones where it inserts the desired holes into the enveloping material.
With the aid of the multiple beam-generating device, it is possible to generate double or multiple beams for producing at least two side-by-side arranged perforation tracks in one and the same perforation zone, wherein the perforation tracks jointly form a perforation pattern in the perforation zone. Through a corresponding guidance and modulation of the double or multiple beams, different perforation patterns can be created in dependence on the desired requirements. One advantage of forming the perforation patterns with several side-by-side arranged perforation tracks is that the desired perforation can be realized over a specified surface and with a specific lengthwise expansion.
German Patent document 195 30 216 A1 discloses a device of the aforementioned type that uses a single laser as the radiation source. The multiple beam-generating device of the known device consists of a beam divider and deflection mirrors, used to generate two beams from the single beam emitted by the radiation source. Modern cigarette machines initially produce double-length cigarettes, which are then cut into individual cigarettes. As a result, the covering paper tape that connects the tobacco rods with the filter segments, or the connected double-length cigarettes, must be perforated in two perforation zones, so that each individual cigarette is provided with a corresponding perforation zone. The double or multiple beams of the known device are therefore additionally divided into respectively two partial beams with the aid of the beam divider. The beam guiding arrangement of this known device is provided with at least one additional deflection mirror. Thus, the known device generates two beams, which are converged in the joint perforation zones to form respectively one multiple beam. In addition, the beam-guiding device requires a specific optical arrangement for focusing the beams in the perforation zones onto the side-by-side extending perforation tracks. It is important that the double or multiple beams are guided at a specific and rather acute angle onto the beam divider of the beam-guiding device, which requires an exact adjustment of the beam divider and the deflection mirrors for the multiple beam-generating device.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a different device and a different method of the aforementioned type.
The above and other objects are achieved according to the invention by the provision of a device for producing zones of desired air permeability in the enveloping material of rod-shaped articles, comprising: a beam-guiding device for focusing a multiple beam generated from a single energy-rich beam originating from a radiation source onto the enveloping material in order to create perforation zones; and a multiple beam-generating device located for creating a multiple beam from the single energy-rich beam, the multiple beam-generating device comprising at least one optical element that is fixed relative to the single energy-rich beam in an operating position of the optical element.
Thus, the foregoing and other objects are solved according to the invention in that the multiple beam-generating device of a device of the aforementioned type is provided with at least one optical element that is fixed in its operating position, relative to the beam from the radiation source.
Optical elements of this type are available for generating the desired multiple beams. With the aid of the invention, it is possible to realize a simple multiple beam-generating device and, in the process, essentially omit all moving optical elements, and those optical elements susceptible to movement, as well as complex optical arrangements. The diffractive optical element can be arranged in the beam path, either before or after the beam-guiding device.
A diffractive optical element in particular is capable of generating the desired slightly diverging double or multiple beams from a single beam, preferably generated by a single source, without requiring additional separate optical elements that may have to be adjusted.
To be sure, the use of diffractive optical elements in a device of the aforementioned type is known from German Patent document 195 11 393 A1 and European Patent Application No. 0 761 376 A1. However, the diffractive optical elements for the known prior art devices are components of the beam-guiding device and are used in the beam-guiding device in particular as beam dividers for dividing the double and multiple beams existing therein. The multiple beam-generating devices of the known systems are composed of different optical elements and thus provide a different type of structural solution. The prior art does not provide a stimulus for using a diffractive optical element, in addition to or in place of the beam-guiding device, either in the multiple beam-generating device or in place of it for generating double or multiple beams before they enter the beam-guiding device. The invention therefore cannot suggest itself as a result of the prior art.
An optical grid is particularly suitable for use as diffractive optical element.
A different advantageous embodiment is provided with an optical element that generates a multiple beam with an even number of partial beams, which exit at an angle relative to each other. This embodiment is distinguished by an optical eleme
Evans Geoffrey S.
Hauni Maschinenbau AG
Kinberg Robert
Venable LLP
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