Abstract:
A closed-loop system can maintain a pre-set cut length of a material as the material is cut and placed on a web. The system has the ability to measure the actual cut length, compare the average actual cut length to a target cut length, and to adjust web tension or feed roll speed to achieve the target cut length. Actual cut length variation is thereby reduced. Furthermore, short term cut length variation is further reduced by minimizing the tension of the web just prior to the material being cut.
Abstract:
A method and apparatus for producing shaped articles from a web material is disclosed. The apparatus generally includes a rotary cutting roller, preferably including indicia on an end surface, and an anvil roller operating in cooperating rotational movement with the rotary cutting roller. The apparatus die cuts web material into predetermined shapes. The apparatus further includes at least one sensor for detecting rotational movement of the rotary cutting die by way of the indicia on the end surface of the rotary cutting roller. The information from the at least one sensor and an encoder is processed and translated to drive means to thereby corrects variation in web alignment relative to the rotary cutting roller. The adjustment of the rotary cutting roller of the present invention allows the rotary cutting roller to cut within a high degree of accuracy and precision.
Abstract:
The described method serves for trimming or cutting during conveyance in a conveying direction (F) substantially in parallel to their main surfaces, flat objects along predetermined cutting lines parallel to the conveying direction (F). The objects are conveyed between a first and a second cutting edge (SK1 and SK2) and are cut by a relative movement of the two cutting edges. The first cutting edge (SK1) is positioned, e.g. stationary, in the plane of a support surface supporting the objects and for each cutting process, the second cutting edge (SK2) is moved past the first cutting edge in such a manner that at least the cutting point on the second cutting edge has a speed component in conveying direction (F) which has the same size as the conveying direction and a speed component perpendicular to the support surface. This is advantageously realized by a swiveling or rotating movement of the second cutting edge (SK2) around a rotation axis (M) arranged above the support surface, whereby for fulfilling the above condition, the distance (y) of the rotation axis from the support surface and the rotation speed (null) are correspondingly matched. Advantageously, a plurality of second cutting edges (SK2) are arranged in a star-shaped manner in a plane perpendicular to the rotation axis (M) and the arrangement of second cutting edges (SK2) is rotated around the rotation axis at a constant speed (null).
Abstract:
A continuous web of sheet material is fed through the nip of a first pair of driven pull rolls around a series of idler rollers and through the nip of a second pair of driven pull rolls. The pairs of pull rolls are selectively rotated to exert a desired tension on the web in a tension zone formed between the pairs of rolls. One pair of pull rolls operates as feed rolls to advance a preselected length of the web to a rotating cutter mechanism so that envelope blanks of a selected length are cut from the web for each revolution of the cutter mechanism. The feed rolls are operated by a servo-controlled motor responsive to an operator initiated signal to adjust the feed length without interrupting the feed of the web to the cutter mechanism. The second pair of pull rolls operates as tension rolls and is servo-motor controlled to maintain a preselected tension on the web fed to the cutter mechanism. The web in the tension zone is rotatably supported by idler rolls having load cells for generating a signal to a controller proportional to the tension applied to the web. Operator input through a keypad to the controller actuates the tension rolls at a gear ratio for generating a desired tension in the web. A deviation in the applied tension from the commanded tension actuates the servo-motor for the tension rolls to adjust the rotation thereof to restore the desired tension in the web.
Abstract:
Apparatus for severing sections from a web by transverse severing cuts at locations related to printed marks on the web. The apparatus includes a rotary cutter and pair of feed rollers, a differential transmission by which the feed rollers are operatively connected to a common drive motor for driving the rotary cutter and the feed rolls. A servomotor is provided for imparting a correcting rotation to the transmission. A mark detector for detecting the printed marks, a sensor for detecting the position of the rotary cutter, and a controller for controlling the servomotor in dependence on the deviation of the spacing of the printed marks from the predetermined web section length are also provided. The servomotor is a stepping motor which receives stepping pulses in a number which represents the difference between the theoretical length of each web section and the actual distance between the printed marks.