Mechanism for changing and cutting film reels

Abstract

Mechanism for changing and cutting film rolls, comprising a hollow roller, the roller having a roller wall and a shaft, the shaft extending transversely and being hollow to form a central suction channel, a cutting blade being arranged in the roller chamber of the roller, the blade edge of which is aligned in the direction of the centrifugal direction of the roller, and a cutting blade drive mechanism being further arranged in the roller chamber of the roller, extending and retracting the cutting blade, a longitudinal slot being formed in the roller wall to expose the blade edge of the cutting blade, the longitudinal slot extending parallel to the central axis of the roller, and air suction openings being provided in sections of the roller wall at the front and rear on both sides of the longitudinal slot, while when the cutting blade is in the extended position, the blade edge of the cutting blade projects beyond the longitudinal slot of the roller.and when the cutting blade is in the retracted position, the blade edge is concealed in the roller chamber of the roller, wherein a suction component is arranged on the outside of the roller, while the suction component is connected to the central suction channel, characterized in that a front vacuum chamber and a rear vacuum chamber are formed separately from each other in the roller chamber of the roller, wherein the two vacuum chambers are arranged at the front and rear on both sides of the cutting blade, respectively, and the longitudinal slot is located between the two vacuum chambers, while the section of the roller wall located at the front end of the longitudinal slot and provided with the air suction openings simultaneously serves as part of the chamber housing of the front vacuum chamber, and the section of the roller wall located at the rear end of the longitudinal slot and provided with the air suction openings,simultaneously serves as part of the chamber housing of the rear vacuum chamber, with the front vacuum chamber being connected to the central suction channel via a front branch line, while the rear vacuum chamber is connected to the central suction channel via a rear branch line.

Description

Technical field

[0001] The present utility model relates to the technical field of devices for film reel winding or film reel changing, in particular a mechanism for changing film reels and cutting film reels. State of the art

[0002] After a film is produced, it is wound onto a take-up reel to form a film reel. The take-up reel consists of a main take-up reel and a spare take-up reel. The main take-up reel winds the film into a film reel during normal operation, while the spare take-up reel takes over the function of the main take-up reel during film reel changes. After the film reel change, the spare take-up reel becomes the new main take-up reel, and the original main take-up reel is removed along with the film reel. The film reel is then detached from the former main take-up reel. Finally, the former main take-up reel is moved to the standby position and becomes the new spare take-up reel. The reel change process requires the use of a film reel changing mechanism and a film reel cutter to cut the film.

[0003] In conventional technology, the cutting blade of the film reel changing and cutting mechanism is mounted on the outside of the reel, with the blade edge oriented transversely (i.e., parallel to the axial direction of the take-up spool). During film cutting, the cutting blade also moves transversely. However, the machine must remain operational during the reel change, with the film continuously being advanced upstream and moving downstream at a speed perpendicular to the cutting blade's movement. Therefore, as the cutting blade traverses the width of the film, the continuous high-speed movement of the film causes the cutting blade to create a diagonal cut line. The adjacent section of film forms a right-angled triangle with a potential length of more than ten meters (depending on the cutting blade's travel speed, the film width, and the film feed speed).For certain high-quality films that require frequent reel changes, this represents a significant waste, and the cut edge of this right-angled triangle must be trimmed before use.

[0004] To solve this problem, the applicant developed a cutting blade mounting structure for winding and changing a film roll, for which a utility model patent was granted under registration number CN 114147798B. This structure makes it possible to align the direction of the cutting line resulting from the film roll change with the transverse direction of the film. This cutting blade mounting structure for winding and changing a film roll comprises a hollow roller whose surface is provided with a longitudinal slot through which the cutting edge protrudes. The longitudinal slot extends parallel to the central axis of the roller. Air intake openings are formed on the surface areas of the roller on both sides of the longitudinal slot. The cutting blade is mounted inside the roller cavity, with its cutting edge aligned in the direction of the roller's centrifugal rotation.A cutting blade drive mechanism for extending and retracting the cutting blade is also located within the roller chamber. The cutting blade drive mechanism may have the structure disclosed in the patent documents with publication numbers CN 119637593B or CN 114147798B. A suction component is mounted on the outside of the roller. A section of the roller is hollow and formed into a straight suction duct through which the suction component is connected to the roller chamber. In this way, a vacuum can be applied during film cutting to adhere the film to the surface of the roller. The adhered film section rotates with the roller, while the cutting blade rotates synchronously with the roller. Thus, both the cutting blade and the film remain stationary in the circumferential direction relative to the roller.When the cutting edge of the blade protrudes from the longitudinal slot, it cuts the film with a line parallel to the central axis of the take-up reel, i.e., in the direction of the profile line on the roller's circumference. This prevents the film from developing a slanted edge, thus avoiding waste.

[0005] In practice, however, the applicant has found that the structure of the aforementioned patent CN 114147798B still has the following deficiencies that need to be improved: Firstly, since the length of the cutting edge of the cutting blade must exceed the width of the film, and secondly, since the length of the longitudinal slot on the roller surface must exceed the length of the cutting edge of the cutting blade, the width of the film must necessarily be less than the length of the longitudinal slot on the roller surface. Furthermore, when the interior of the roller is evacuated, the film, while covering the outside of the longitudinal slot, does not completely cover the slot in the transverse direction. Consequently, uncovered sections of the longitudinal slot allow air to enter, compromising the vacuum level inside the roller. This weakens the suction of the air intake openings on the roller surface, making it difficult to cut the film cleanly and precisely.

[0006] Secondly, the cutting edge of the blade must extend a certain distance beyond the longitudinal slot to generate sufficient cutting force and begin cutting through the film. As shown in the Fig. 1 and Fig. As shown in Figure 2, the film 8 is lifted, forming a triangular gap, before the cutting blade 2 extends beyond the longitudinal slot 13 and begins cutting the film 8. The cross-sectional area of ​​this triangular gap is shown in Figure 2. Fig. 2 is shown as area ABC. At this stage, outside air initially penetrates from the side (as shown by arrow a in). Fig. 2 shown) and then radially along roller 1 (as shown by arrow b in Fig. 2 shown) into the interior of roller 1. This further reduces the negative pressure in the cavity of roller 1, thereby decreasing the suction force of the air intake openings on the roller surface and thus making it more difficult to cut the film.

[0007] For the reasons mentioned above, the structure of CN 114147798B cannot securely hold the film on both sides of the cutting blade during the cutting process when changing rolls due to insufficient suction power of the air suction openings, which easily leads to cutting difficulties. Content of the utility model

[0008] The present utility model aims to overcome the aforementioned disadvantages by providing a mechanism for changing and cutting film rolls in which the cutting line when cutting the film runs parallel to the central axis of the take-up spool, thereby avoiding cutting difficulties due to insufficient suction power of the air suction openings of the roller.

[0009] The purpose can be achieved with the aid of the following scheme: a mechanism for changing and cutting film rolls, comprising a hollow roller, the roller having a roller wall and a shaft, the shaft extending transversely and being hollow to form a central suction channel, while a cutting blade is arranged in the roller chamber of the roller, the blade edge of which is aligned in the direction of the centrifugal direction of the roller, and a cutting blade drive mechanism is further arranged in the roller chamber of the roller, extending and retracting the cutting blade, a longitudinal slot being formed in the roller wall to expose the blade edge of the cutting blade, the longitudinal slot extending parallel to the central axis of the roller, and air suction openings being provided in sections of the roller wall at the front and rear on both sides of the longitudinal slot, while when the cutting blade is in the extended position,the cutting edge of the cutting blade projects beyond the longitudinal slot of the roller, and when the cutting blade is in the retracted position, the cutting edge is concealed in the roller chamber of the roller, wherein a suction component is arranged on the outside of the roller, while the suction component is connected to the central suction channel, characterized in that a front vacuum chamber and a rear vacuum chamber are formed separately from each other in the roller chamber of the roller, wherein the two vacuum chambers are arranged at the front and rear on both sides of the cutting blade, respectively, and the longitudinal slot is located between the two vacuum chambers, while the section of the roller wall located at the front end of the longitudinal slot and provided with the air suction openings simultaneously serves as part of the chamber housing of the front vacuum chamber, and the section of the roller wall,which is located at the rear end of the longitudinal slot and is provided with the air intake openings, simultaneously serves as part of the chamber housing of the rear vacuum chamber, the front vacuum chamber being connected to the central suction channel via a front branch line, while the rear vacuum chamber is connected to the central suction channel via a rear branch line.

[0010] The air intake openings in the roller wall are arranged in several rows, with the individual air intake openings within the same row having the same circumferential position, and the opening diameter of the first row of air intake openings, which are located in front of the front vacuum chamber, being smaller than that of the other air intake openings of the front vacuum chamber.

[0011] The opening diameter of the second row of air intake openings located in front of the front vacuum chamber is smaller than that of the third row of air intake openings located in front of it.

[0012] During operation, the roller rotates continuously in one direction, with the longitudinal slot and air intake openings rotating along with it. When referring to the front and rear directions of components relative to the roller, this means the front and rear directions in the sense of rotation.

[0013] The circumferential direction refers to the circumferential direction of the roller wall.

[0014] The present utility model offers the following advantages and effects: I. The present utility model prevents cutting difficulties caused by insufficient suction power of the air intake openings. This is primarily due to the following reasons: 1. The air intake openings on the roller surface are not connected to the roller's longitudinal slot. Therefore, no air loss occurs, even if the film does not cover the entire width of the longitudinal slot. Furthermore, air loss is prevented if the film is temporarily lifted by the cutting blade and cannot cover the longitudinal slot, thus maintaining the vacuum level in the vacuum chambers. 2. The volume of the front vacuum chamber and the rear vacuum chamber can be significantly smaller than the volume of the entire roller chamber. Compared to the structure disclosed in CN 114147798B, the present utility model therefore requires the evacuation of a significantly smaller volume, thus facilitating the rapid achievement of a high vacuum level. II. During the roll-changing process of the present utility model (including the cutting process and the pre-cutting preparation phase, during which the suction component is activated), the separation point between the film and the roller shifts continuously along the roller's circumferential surface. Consequently, the separation point between the film and the roller repeatedly passes through the air suction openings, where the negative pressure exerted by the air suction openings exerts a significant adhesive force on the film. In a preferred embodiment of the present utility model, the opening diameter of the foremost row of air suction openings in the front negative pressure chamber is smaller than that of the other air suction openings in the front negative pressure chamber.Therefore, if the film separation point from the roller occurs at the circumferential position of the foremost row of air intake openings, the minimal opening diameter of this row results in a negligible suction force. This ensures that the film separation process from the roller is not impaired. Furthermore, the opening diameter of the foremost row of air intake openings in the front vacuum chamber is smaller than that of the second row of air intake openings upstream. The opening diameter of the second row of air intake openings upstream of the front vacuum chamber is smaller than that of the third row of air intake openings upstream. Thus, the opening diameter of the air intake openings upstream of the front vacuum chamber gradually increases along the circumference of the roller.This prevents sudden fluctuations in adhesion caused by abrupt, significant changes in vacuum, thus avoiding variations and oscillations in film tension. This prevents film stretching and also helps ensure that the outer film layers wound onto the film reel appear smooth and uniform. Furthermore, the foremost row of air intake openings in the front vacuum chamber is located far from the longitudinal slot on the reel surface, so even their minimal suction does not impair the strong adhesion near the film's cutting line. Illustration of the attached figures Fig. Figure 1 illustrates the air leakage that occurs during the cutting process in a conventional film roll changing and film roll cutting mechanism in the vacuum roller; Fig. Figure 2 is an enlarged schematic representation of section D in Fig. 1; Fig. Figure 3 is a schematic front view of the structure of the roller in a detailed embodiment of the present utility model; Fig. 4 is a schematic side view of the in Fig. 3 rollers shown; Fig. Figure 5 is a schematic representation of the structure of the local cross-section of GG in Fig. 3; Fig. Figure 6 is a schematic representation of the structure of the rear vacuum chamber and the front vacuum chamber, which are located in Fig. 5 are shown; Fig. Figure 7 is a schematic representation of the structure of the cross-section of EE in Fig. 5; Fig. Figure 8 is a schematic representation of the structure of the cross-section of FF in Fig. 5; Fig. Figure 9 is an enlarged schematic representation of a section from Fig. 8; Fig. Figure 10 is a schematic representation of the structure of the local cross-section of HH in Fig. 5; Fig. Figure 11 shows the state of the separating film at the location of the first row of air intake openings in front of the front vacuum chamber during the operation of a detailed embodiment of the present utility model; Fig. Figure 12 shows the changed state of the in Fig. 11 depicted cylinder, after it has rotated by a further specific angle. Detailed descriptions

[0015] The Fig. 3, Fig. 4, Fig. 5, Fig. 7 and Fig. Figure 8 shows a mechanism for changing and cutting film rolls, comprising a hollow roller 1. The roller 1 includes a roller wall 11 and a shaft 10, the shaft 10 extending transversely. The shaft 10 is hollow and forms a central suction channel 12. The central suction channel 12 has a suction opening 120, the suction opening 120 being located at the right end of the shaft 10.

[0016] The Fig. 5, Fig. 6 and Fig. Figure 7 shows that a cutting blade 2 is arranged in the roller chamber of the roller 1, the blade edge of the cutting blade 2 being oriented in the direction of the centrifugal direction of the roller 1. A cutting blade drive mechanism 7 for extending and retracting the cutting blade is also arranged in the roller chamber of the roller 1, the cutting blade drive mechanism 7 being driven by a pneumatic cylinder. The left end section of the shaft 10 also includes a hollow air supply channel 15, the pneumatic cylinder being connected to an external air supply component via the air supply channel 15. A longitudinal slot 13 is formed in the roller wall 11 to expose the blade edge of the cutting blade 2, the longitudinal slot 13 extending parallel to the central axis of the roller 1 and air intake openings 14 being provided in sections of the roller wall 11 at the front and rear on both sides of the longitudinal slot 13, while, as in Fig. Figure 5 shows that the cutting blade 2 is in the extended position, the blade edge of the cutting blade 2 projects beyond the longitudinal slot 13 of the roller, and when the cutting blade 2 is in the retracted position, the blade edge of the cutting blade 2 is hidden in the roller space of the roller 1, with a suction component arranged on the outside of the roller, while the suction component is connected to the suction opening 120 of the central suction channel 12.

[0017] The Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9 and Fig. Figure 10 shows that in the roller chamber of roller 1, a partition plate 16 divides the space to form a front vacuum chamber 3 and a rear vacuum chamber 4. The front vacuum chamber 3 is located in front of the cutting blade 2, while the rear vacuum chamber 4 is located behind the cutting blade 2. The longitudinal slot 13 is located between the front vacuum chamber 3 and the rear vacuum chamber 4. The section of the roller wall located in front of the longitudinal slot 13 and provided with air intake openings 14 also serves as part of the chamber housing of the front vacuum chamber 3. The section of the roller wall located behind the longitudinal slot 13 and provided with air intake openings also serves as part of the chamber housing of the rear vacuum chamber 4. As shown in Fig. As shown in Figure 8, the front vacuum chamber 3 is transversely divided into five units to facilitate machining and manufacturing. Each pair of adjacent units is connected transversely via a vent, ensuring that the five units of the front vacuum chamber 3 are interconnected. Similarly, the rear vacuum chamber 4 is transversely divided into five units. Each pair of adjacent units is connected transversely via a vent, ensuring that the five units of the rear vacuum chamber 4 are interconnected.

[0018] As in the Fig. 4, Fig. 5 and Fig. As shown in Figure 6, the front vacuum chamber 3 is connected to the central suction channel 12 via a front branch line 5, while the rear vacuum chamber 4 is connected to the central suction channel 12 via a rear branch line 6. Both the front branch line 5 and the rear branch line 6 are located inside the roller. The air intake openings 14 in the roller wall are arranged in several rows, with each individual air intake opening 14 occupying the same circumferential position within the same row. As shown in the Fig. 5 and Fig. Figure 6 shows the opening diameter of the first row of air intake openings 14 (the air intake openings on the far left in the Fig. 5 and Fig. 6), which are located in front of the front vacuum chamber, are smaller than the opening diameter of the other air intake openings 14 in the front vacuum chamber. The opening diameter of the second row of air intake openings 14 (the second air intake opening from left to right in the Fig. 5 and Fig. 6), which is located in front of the front vacuum chamber, is smaller than that of the third row of air intake openings 14 (the third air intake opening from left to right in the Fig. 5 and Fig. 6).

[0019] During operation, roller 1 rotates continuously in one direction counterclockwise (as indicated by the arrows in the Fig. 5, Fig. 6 and Fig. (11 shown), wherein the longitudinal slot 13 and the air intake openings 14 rotate continuously. When reference is made to the front and rear directions of components with respect to the roller 1, this denotes the front and rear directions in the direction of rotation, with the counterclockwise direction being the front direction.

[0020] The operating principle of the above-mentioned embodiment is as follows: The process of changing reels and editing film includes a preparation phase and a cutting blade operation phase: (I) Preparation Phase: As the film reel approaches the preset cut length, the suction component is activated and gradually begins operating until it reaches a state of maximum suction. Upon reaching this state, and because the front vacuum chamber 3 and the rear vacuum chamber 4 have a very small chamber volume, the vacuum in these chambers becomes sufficiently strong when all air suction openings 14 are enclosed by the film 8, thus completing the preparation phase. Throughout the preparation phase, the roller 1 remains in rotation, completing several revolutions. The film is repeatedly wound around the outside of the air suction openings 14 on the roller 1 and then unwound. As described in Fig. As shown in Figure 11, the minimum opening diameter of the air intake openings 14 upstream of the front vacuum chamber results in weak suction at the air intake openings 14 upstream of the front vacuum chamber when the separation point occurs at the first row of air intake openings 14 upstream of the front vacuum chamber. This facilitates film separation. When the separation point occurs at the second row of air intake openings 14 upstream of the front vacuum chamber, the first row of air intake openings 14 is no longer enclosed by the film. Consequently, a slight air leak occurs through the first row of air intake openings 14, reducing the vacuum in the front vacuum chamber 3. Furthermore, the opening diameter of the second row of air intake openings 14 is smaller than that of the third row of air intake openings 14. Consequently, the film also tends to separate at the location of the second row of air intake openings 14.Subsequently, the second row of air intake openings 14 in the front vacuum chamber 3 continues to vent air, thereby reducing the vacuum level in the front vacuum chamber 3. This facilitated the separation of the film 8 from the corresponding air intake openings of the front vacuum chamber, as shown in . Fig.Figure 12 illustrates this. When the film's separation point coincides with the air intake openings of the rear vacuum chamber 4, the vacuum level in the rear vacuum chamber 4 remains low due to its indirect connection to the front vacuum chamber 3 (via the rear branch line 6, the central suction channel 12, and the front branch line 5). This low vacuum level facilitates film separation. As the process described above demonstrates, despite the high vacuum level in the vacuum chamber during the pre-cutting preparation phase—when the film completely covers all air intake openings—only minimal tension fluctuations occur when separating the film from the reel. This prevents sudden fluctuations in adhesion caused by abrupt, significant changes in vacuum, thus avoiding film tension variations and oscillations.This prevents the film from stretching and also helps to ensure that the outer film layers, which are wound onto the film reel, appear smooth and even.

[0021] During the aforementioned preparation phase, the pneumatic cylinder of the cutting blade drive mechanism must also be filled with air.

[0022] (II) Cutting blade operating phase: Once the suction component has reached its maximum suction capacity and the pneumatic cylinder of the cutting blade drive mechanism is completely filled with air, the cutting blade drive mechanism 7 can be activated at the appropriate time. The moment the film 8 surrounds all air suction openings 14, the cutting blade 2 is rapidly extended through the longitudinal slot 13 by the cutting blade drive mechanism 7. During this process, the film 8 is pressed firmly and securely against the cutting blade 2 from both the front and rear, on both sides, by the air suction openings 14 of the front vacuum chamber 3 and the rear vacuum chamber 4. This allows the cutting blade 2 to cleanly cut the film 8. Finally, the cutting blade 2 is retracted back into the roller chamber of the roller 1 by the cutting blade drive mechanism 7.

[0023] A mechanism for changing and cutting film rolls, comprising a hollow roller, the roller having a roller wall and a shaft, the shaft being hollow to form a central suction channel, a cutting blade being arranged in the roller chamber of the roller, and a cutting blade drive mechanism being further arranged in the roller chamber of the roller for extending and retracting the cutting blade, a longitudinal slot being formed in the roller wall to expose the blade edge of the cutting blade, and air suction openings being provided in sections of the roller wall at the front and rear on both sides of the longitudinal slot, a front vacuum chamber and a rear vacuum chamber being formed separately from each other in the roller chamber of the roller, the two vacuum chambers being arranged at the front and rear on both sides of the cutting blade, respectively, and the longitudinal slot being located between the two vacuum chambers.wherein the front vacuum chamber is connected to the central suction channel via a front branch line, and the rear vacuum chamber is connected to the central suction channel via a rear branch line. In this utility model, the cutting line when cutting the film runs parallel to the central axis of the take-up reel, thus avoiding cutting difficulties due to insufficient suction power of the roller's air intake openings. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 114147798B [0004, 0005, 0007, 0014] CN 119637593B

[0004]

Claims

[1] A mechanism for changing and cutting film rolls, comprising a hollow roller, the roller having a roller wall and a shaft, the shaft extending transversely and being hollow to form a central suction channel, a cutting blade being arranged in the roller chamber of the roller, the blade edge of which is aligned in the direction of the centrifugal direction of the roller, and a cutting blade drive mechanism being further arranged in the roller chamber of the roller for extending and retracting the cutting blade, a longitudinal slot being formed in the roller wall to expose the blade edge of the cutting blade, the longitudinal slot extending parallel to the central axis of the roller, and air suction openings being provided in sections of the roller wall at the front and rear on both sides of the longitudinal slot, while when the cutting blade is in the extended position, the blade edge of the cutting blade projects beyond the longitudinal slot of the roller.and when the cutting blade is in the retracted position, the blade edge is concealed in the roller chamber of the roller, with a suction component arranged on the outside of the roller, while the suction component is connected to the central suction channel, characterized by, that a front vacuum chamber and a rear vacuum chamber are formed separately from each other in the roller chamber of the roller, wherein the two vacuum chambers are arranged at the front and rear on both sides of the cutting blade and the longitudinal slot is located between the two vacuum chambers, while the section of the roller wall located at the front end of the longitudinal slot and provided with the air intake openings serves simultaneously as part of the chamber housing of the front vacuum chamber and the section of the roller wall located at the rear end of the longitudinal slot and provided with the air intake openings serves simultaneously as part of the chamber housing of the rear vacuum chamber, wherein the front vacuum chamber is connected to the central suction channel via a front branch line, while the rear vacuum chamber is connected to the central suction channel via a rear branch line. [2] Mechanism for changing and cutting film rolls according to claim 1, characterized by , that the air intake openings in the roller wall are arranged in several rows, wherein the individual air intake openings within the same row have the same circumferential position, and the opening diameter of the first row of air intake openings located in front of the front vacuum chamber is smaller than that of the other air intake openings of the front vacuum chamber. [3] Mechanism for changing and cutting film rolls according to claim 1, characterized by , that the opening diameter of the second row of air intake openings located in front of the front vacuum chamber is smaller than that of the third row of air intake openings located in front of it.

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