Views:7 Author:Site Editor Publish Time: 2017-02-14 Origin:Site
Oscillating knife cutting machine, in particular cutting machines for cutting plastic and foamed materials, are faced with ever increasing demands with respect to cutting quality, speed and robustness. The plastic and foamed materials to be cut with the cutting machines become ever heavier and harder or resistant to crushing. Examples of materials to be cut are not only found in the field of comfort foam, such as with mattresses or furniture, for example, but hard and semi-hard PU, PE or PS foams also have to be cut, these foamed materials finding their application in insulations for buildings, refrigerators or vehicles.
For several years, band Oscillating knife cutting machine are used to cut and severe foamed materials etc. The band knives run over a plurality of knife deflecting pulleys and span freely in a cutting zone for a length of up to 2.5 m. Such a cutting machine is known, for example, from the applicant's documents DE 11 84 069 or DE 75 50 595. With such cutting machines, however, it is necessary to return the band knife above the material so that a large frame is required for the circulating band knife. A cutting machine is known from DE 101 29 909, in which the band knife is twisted by means of a knife rotating head, so as to perform contour cutting.
It is further known that cutting machines may use knives guided in opposed directions. These are advantageous in that a particularly advantageous cutting becomes possible, since the arrangement of the knives in opposed directions results, seen on a microscopic level, in a tearing of the material, where the arrangement in opposed directions allows effecting the tearing at twice the speed of a knife guided in a single direction.
Band knives guided in opposed directions are known, for example, from JP 06182691 and DE 101 29 909 A1.
Some known cutting machines with knives guided in opposed directions have a problem that contour cutting is difficult to perform with these, since, due to the type of knife guiding, a large part of the machine would have to be taken along as the cutting portion of the knife is turned. Turning only the cutting portion of the band knife, as described above, is not possible with a double band knife, since the band knives would become offset with respect to each other if they were twisted.
For the Oscillating knife cutting machine known for example from DE 101 29 909 A1, it has been found, however, that the service life of the knives is relatively short due to the great stress in the guiding means.