Apparatus and method for severing or separating a web

Abstract

An apparatus, system and method are disclosed for separating and/or winding a web. A web is adhered by vacuum force to a rotating transfer roll. A turret is provided that is capable of indexing about a longitudinal axis, the turret having a plurality of mandrels rotatably affixed to the turret. A web passes to the transfer roll and to winding position of the turret. A severing means, such as an air knife, water knife, interference device, or severing roll is configured to separate the web. The web may be synthetic, textile, or paper. The web may be perforated at periodic intervals so that the web sections may be separated at pre-existing perforations and then wound upon mandrels of the turret in a continuous operation.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from previously filed Provisional Application No. 60/243,983 which was filed in the United States on Oct. 27, 2000.

BACKGROUND OF THE INVENTION

[0002] Products formed from webs, such as tissues, paper towels, and the like typically are wound upon large supply rolls after manufacture of the paper stock. To prepare such rolled products for consumer use, the paper must be rewound into smaller sized rolls, placed upon cores, and cut, to provide an appropriate sized individual paper product for use.

[0003] In conventional systems, a core is placed upon a mandrel that is capable of spinning. Thus, rotation of the mandrel in conjunction with the core may wind the paper upon the core. Techniques for using mandrels for winding paper are known in the art. For example, a turret style winding system is a known method used to wind paper onto a core. Most turret systems include a number of mandrels that each is capable of spinning independently of each other so that multiple paper logs may be formed simultaneously. Then, the logs may be cut into smaller rolls in a later step. The cored rolls then are removed from the mandrel.

[0004] Some current continuous center-winding systems provide a web that is cut by engaging a web cut-off knife from a rotating bedroll. In many such systems, the engaging mechanism actually rotates with the roll, and is mounted inside or upon the roll. The timing and engagement of the knife in current continuous center-winding systems may be adversely affected by increasing centrifugal forces placed upon the mechanism by high rotational speeds of the bedroll.

[0005] As manufacturing line-processing speeds continually increase, the adverse affect of increased centrifugal forces upon rotating knife engaging mechanisms has become a significant challenge. The timing, set-up and engagement of such mechanisms are undesirably affected by centrifugal forces upon the relatively delicate mechanical apparatus. Movement of these mechanisms sometimes adversely affects the rotational balance of the bedroll, which may induce undesirable vibration into the winder. This may cause perforations in the tissue to be incorrectly applied or uneven, and may undesirably increase equipment wear.

[0006] A need exists for an improved separating apparatus, system, and method for separating webs. Further, a system that is capable of transferring the separated web portions to cores at higher line speeds would be desirable. Further, a severing or separating mechanism that is not adversely affected or rendered inoperable by centrifugal forces acting upon the bedroll would be desirable.

SUMMARY OF THE INVENTION

[0007] The invention provides an improved severing apparatus and process for separating or severing running webs. The invention may provide for the separation of the web into an upstream portion and a downstream portion. Subsequently, the downstream portion of the web may be wound into a roll. The invention is not limited to paper webs, but may be employed with essentially any web or sheet material that is to be cut to length in the process of manufacture or rolling. Thus, the web may comprise textiles, fabrics, nonwoven materials, paper, fibrous based web, and others. The invention is particularly useful for applications that include winding a web or sheet material into rolls at high processing speeds.

[0008] The invention may include a rotating transfer roll. In some embodiments, the rotating transfer roll may be configured to carry a web on its exterior surface, the rotating transfer roll optionally including a transfer pad. A transfer pad may be adapted for applying a releasable suction force to adhere the web to the transfer roll. A severing device also is provided. The severing device is configured to separate the web into portions. In one aspect of the invention, a severing roll is employed instead of the severing device. The severing roll, when it is used, is configured to separate the web into portions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] A full and enabling disclosure of this invention, including the best mode shown to one of ordinary skill in the art, is set forth in this specification. The following Figures illustrate the invention:

[0010] FIG. 1 reveals a configuration of the invention with a severing device located in close proximity to a vacuum assisted transfer roll;

[0011] FIG. 2 is a perspective view of the embodiment of FIG. 1 a short time after the time shown in FIG. 1, in which the transfer pad causes the web to contact the core, and the vacuum source may no longer be applied; and

[0012] FIG. 3 shows an alternate configuration of the invention with a severing roll located in close proximity to a vacuum assisted transfer roll.

[0013] Repeated use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of various embodiments of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Reference now will be made to the embodiments of the invention, one or more examples of which are set forth below. Each example is provided by way of explanation of the invention, not as a limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in this invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention cover such modifications and variations as come within the scope of the appended claims and their equivalents. Other objects, features and aspects of the present invention are disclosed in or are obvious from the following detailed description. It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions.

[0015] The various embodiments of the invention may be distinguished by several features. Several embodiments of the invention are shown in the drawings, and other embodiments of the invention not shown easily could be realized by persons of skill in the art upon review of this specification. The invention is not limited by the specific embodiments shown in the appended drawings.

[0016] In one embodiment of the invention, as shown in FIG. 1, a severing device 25 is adapted for engagement with a web 23 and transfer roll 21. A vacuum space 22 may be located within the transfer roll 21. Vacuum space 22 applies a low ambient pressure condition or suction force that is communicated through transfer pad 26, which may be partially embedded in transfer roll 21. The transfer pad 26 and the vacuum insert 38 are perforated with vacuum holes or slots (not shown), which are adapted for air circulation that serves to pull the web 23 tightly against its surface. Further, a vacuum insert 38 provides a suction force on the trailing edge, pulling the web 23 against the surface.

[0017] The vacuum assisted transfer roll 21 transports the leading edge of the web 23 in a rotational path, as shown in the FIG. 1. The severing device 25 may be adapted to separate the web 23 into sections or portions as further discussed below. In one embodiment, the severing device 25 separates the web 23 into a downstream portion 42 and an upstream portion 43 (see FIG. 2). This separation may be a complete cut, in the case of a web 23 that is not perforated, or can be simply a separation of a web 23 at an existing perforation, such as perforation 24. The perforations such as perforation 24 typically run along the cross direction of the web 23, as shown in FIGS. 1-3.

[0018] In the practice of the invention, the leading edge of the web 23 approaches the cored mandrel 28 as the web 23 travels in a circular fashion around the outer edge of the transfer roll 21. Cored mandrel 28 is shown in FIG. 1 ready to receive web 23, and may have adhesive that has been deposited upon its surface to adhere the leading edge of the web 23 to the surface of the cored mandrel 28 once the cored mandrel 28 has been rotated into position to receive the web 23. In other embodiments, vacuum suction forces may hold the tail of the web 23 upon the cored mandrel 28 until the web 23 has begun winding. The latter method sometimes does not need adhesive at all.

[0019] The severing device 25 may be comprised of a high-speed air knife, a high-speed water knife, a cut-off knife, or an interference device, as examples.

[0020] In some embodiments of the invention, a servo motor may control the motion of severing device 25.

[0021] The severing device 25 may be fixed in a non-rotating position in close proximity to the rotating transfer roll 21. The severing device 25 may send a component (not shown, such as a blade) or a high speed water stream (in the case of a water knife, for example), or a high speed air stream (in the case of an air knife, for example) into channel 27 to sever the web 23. Then, the transfer pad 38 causes the web 23 to contact and adhere to the cored mandrel 28. The vacuum source can be disengaged or turned off as shown in FIG. 2 to facilitate release and winding of the downstream portion 42 of the web 23.

[0022] Turret 36 is shown with a central axis 35. Many turret assemblies known in the art are suitable for use in connection with the present invention. Examples of various turret assemblies that may be used in the present invention include, but are not limited to, the turret assemblies described in U.S. Pat. Nos. 4,133,495 to Dowd; 5,337,968 to De Bin et al.; and 5,797,559 to Coffey.

[0023] In general, the motion of the cored mandrel 28 from the pre-spin position (see cored mandrel 29) to the transfer position (see winding roll 32) must be completed during the transfer roll revolution so that the web 28 which is carried upon the surface of the transfer pad 26 does not contact the incoming cored mandrel 28 prematurely. A complete roll 33 is shown at the next successive mandrel position. Mandrel 30 and mandrel 31 are shown at the next successive positions.

[0024] In another embodiment of the invention, there is provided a rotating severing roll 40 to separate the paper web into sections at periodic intervals. FIG. 3 shows like components having the same numerals as shown in FIGS. 1-2. However, in the embodiment of the invention as shown in FIG. 3, a rotating severing roll 40 is provided. The embodiment of the invention shown in FIG. 3 differs from that shown in FIGS. 1-2. The severing roll 40 rotates, and is timed to sever the web 23 at precisely the correct moment to create a downstream portion of web 23 of appropriate length for winding on winding roll 32.

[0025] The timing between the transfer roll 21, the application of the suction force or vacuum, the leading edge of the web 23, and the mandrels of turret 36 may be monitored and controlled by an electronic position sensing and control system. Such a system is generally known to persons of skill in the art. Further, the timing of the vacuum onset and vacuum release may be adjusted relative to the position of the transfer roll 21 by moving a vacuum shoe (not shown) which is provided at the transfer roll 21.

[0026] It is understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary constructions. The invention is shown by example in the appended claims.

Claims

1. An apparatus for severing a web, comprising:

a rotating transfer roll, the rotating transfer roll being configured to carry a web on its exterior surface; and

a severing means, the severing means being configured to engage and separate the web into an upstream portion and a downstream portion.

2. The apparatus of claim 1 in which the severing means comprises an air knife.

3. The apparatus of claim 1 in which the severing means comprises a water knife.

4. The apparatus of claim 1 in which the severing means comprises an interference device.

5. The apparatus of claim 1 in which the severing means comprises a severing roll.

6. The apparatus of claim 1 additionally comprising:

a servo motor to direct the movement of the severing means in separating the web.

7. The apparatus of claim 1 in which the transfer roll is configured to employ a suction force, thereby adhering the web to its exterior surface.

8. The apparatus of claim 7 in which a transfer pad is employed to apply the suction force to the web.

9. An apparatus for severing a web, comprising:

a rotating transfer roll, the rotating transfer roll being configured to carry a web on its exterior surface, the rotating transfer roll having on its exterior surface a transfer pad, the transfer pad being adapted for applying a releasable suction force to releasably adhere the web to the transfer roll; and

a severing device, the severing device being configured to separate the web into portions.

10. The apparatus of claim 9 additionally comprising:

a channel upon the exterior surface of the rotating transfer roll, the channel being configured to receive at least one component of the severing device in separating the web.

11. The apparatus of claim 9 in which the severing device is adapted to sever the web at a pre-existing perforation.

12. The apparatus of claim 9 additionally comprising:

a servo motor configured to control movement of the severing device.

13. The apparatus of claim 9 in which the transfer pad is positioned along the width of the transfer roll to engage the web in its cross direction.

14. An apparatus for separating a web, comprising:

a rotating transfer roll, the rotating transfer roll being configured to carry a web on its exterior surface, the rotating transfer roll having on its exterior surface a transfer pad, the transfer pad being adapted for applying a suction force to releasably adhere the web to the transfer roll; and

a severing roll, the severing roll being configured to separate the web into portions.

15. A method of separating a web, the method comprising:

(a) providing a web,

(b) rotating a transfer roll,

(c) adhering the web to the surface of the transfer roll using a suction force,

(d) providing a severing device, the severing device being selected from the group of devices comprising: air knife, water knife, interference device, and severing roll, and

(e) separating the web.

16. The method of claim 15 further wherein step (e) additionally comprises:

engaging the transfer roll with at least one component of the severing device in separating the web.

17. The method of claim 15 further comprising the step of:

(f) releasing the web.

18. The method of claim 17 wherein the releasing step (f) is accomplished by removing the suction force from the web.

19. The method of claim 17 further comprising the step of:

(g) winding the web into a roll.

20. The method of claim 15 in which the severing device is a water knife.

21. The method of claim 15 in which the severing device is an air knife.

22. The method of claim 15 in which the severing device is an interference device.