CA2605810A1 - Method and apparatus to continuously separate cut pieces from flexible material - Google Patents

Abstract

A fully addressable vacuum/ positive pressure roller may select and remove pattern pieces that have been severed or cut from a web or sheet of flexible material even though the pattern pieces are still embedded within the web, both being supported on a common surface. Vacuum rollers may be disposed along the path of an advancing web with the rollers being oriented such that each roller's axis of rotation is both orthogonal to the advance direction of the web and orthogonal to the surface normal of the web so that the web travels around at least a portion of the arc of each roller. The vacuum roller for conveying the web or sheet type material includes an external surface having a plurality of apertures there through. A plurality of addressable valves are in corresponding fluid communication with the plurality of apertures. By controlling the state of each of the plurality of valves, the user may selectively address each valve independently in order to achieve a desired state of each of the valves at all times and/ or positions during operation.

Description

Method and Apparatus to Continuously Separate Cut Pieces from Flexible Material This application claims the benefit of United States Provisional Application No. 60/677,244, filed May 3, 2005 and entitled Vacuum Roller.
BACKGROUND OF THE INVENTION

This invention relates to the field of selecting and removing pattern pieces that have been severed or cut from a web or sheet of flexible material, while the pattern pieces are still embedded within the web, both being supported on a common surface.

This invention also relates to the field of vacuum rollers where one or more said rollers are disposed along the path of an advancing web said rollers being oriented such that each roller's axis of rotation is both orthogonal to the advance direction of the web and orthogonal to the surface normal of the web and said rollers. are positioned such that the web travels around at least a portion of the arc of each said roller.

This invention also relates to the field of steering and guiding webs, tapes, sheets and conveyer belts both with uniform material properties, and those with non-uniform material properties.

This invention also relates to the field of effecting or influencing a process to be performed on a web, tape, sheet or conveyer belts where the level of pressure on the web must be applied in an arbitrary programmed manner over the material surface.

The webs or sheets are normally comprised of films, laminates, fibers woven materials or animal hides as are used in technical textiles, apparel, furnishings, engineering membranes, composite materials such as tapes, wovens that may be pre-impregnated with adhesives or liner material and nanostructured compositions such as distributed or aligned carbon nanotubes which may further be embedded in a polymer web or sheet. Semi rigid foils and semi rigid sheet metal webs or pieces may also be manipulated with the apparatus described here.

The web or sheet in which the pattern pieces are embedded is supported on a planar, cylindrical, or curved surface. The vacuum roller axis may be in relative translational motion to the material support surface. The vacuum roller has its rotational axis orthogonal to the relative direction of travel of the material surface and orthogonal to the normal vector of the material surface.

The vacuum roller is rotating so that the surface of the vacuum roller and the surface of the material are in registration (no relative motion).

Prior art vacuum roller designs present a variety of methods to achieve the application of selective vacuum to a portion of the arc of a roller. This arc portion is to remain generally stationary with respect to the machine configuration, such that as the roller rotates, its surface ports are successively ported to either vacuum, pressure or closed.

Most of these designs are intended to provide vacuum retention and motion to a web or sheet of flexible material by "pulling" vacuum through the surface of a roller into the hollow core of the roller. The core has a rotating joint at one or both ends that allows the attachment of a non-rotating vacuum hose to a remote vacuum pump or source.

In the prior art, the general design schemes provide for the "zoning" of vacuum and or positive pressure to a portion of the arc of the roller. Vacuum is ported to the roller surface to draw the web or sheet into intimate contact with the roller surface. At a pre-determined position of rotation, usually when the sheet leading edge is tangent to another roller, the vacuum is switched to a positive pressure to "push" the sheet or web leading edge away from the current roller onto the next roller or conveyer. These roller pressure transitions are effected at specific arc locations and are in effect across the length of the roller at any specific arc position.

The prior art vacuum roller systems lack the ability to selectively control the presence of vacuum at each of the surface ports of the roller independently of one another. The prior art fails to provide a mechanism to permit roller pressure transitions which do not either apply to an entire row of surface ports along the roller or to an entire ring of surface ports around the circumference of the roller.

SUMMARY OF THE INVENTION

In accordance with the present invention, there is provided a fully addressable vacuum/pressure roller. A vacuum roller for conveying a web or sheet type material, comprises a rotatable roller having an external surface.
The rotatable roller has a plurality of bores there through, each of which bores terminates at a surface port in the external surface of the rotatable roller.
A
plurality of addressable valves are in fluid communication with the plurality of bores. The plurality of addressable valves is also in fluid communication with both a vacuum source and a pressure source. A means for addressably controlling the state of each of the plurality of valves is provided to selectively permit the fluid communication through a respective one of the bores between the vacuum source or pressure source and a respective one of the surface ports. One method to addressably control each of the plurality of valves is to utilize a programmable controller programmed with software that performs the switch sequencing and a data base or data file that the software accesses, the data represents the desired state of each of the valves at all times and/or positions during operation.

A valve assembly is provided for use in a rotatable vacuum roller having an external surface and a plurality of bores there through, each of which bores terminates at a surface port in said external surface of the rotatable roller. The valve assembly comprises a plurality of addressable valves each of which is in fluid communication with a vacuum source and a pressure source and one of said surface ports. A means for addressably controlling the state of each of the plurality of valves is provided to selectively permit the fluid communication through a respective one of the bores between the vacuum source or the pressure source and a respective one of the surface ports.

The present invention describes a vacuum roller that allows the selective application of vacuum or pressure to any desired surface port around the roller's circumference and along the roller's length. This is programmable so that any selected surface port may have its state changed at any time during operation. This "porting" is dynamic. The addressable valve in fluid connection with each surface port cari be switched instantly while the roller is rotating.

BRIEF DESCRIPTION OF DRAWINGS

Figure 1A is a perspective view of a schematic of an apparatus in accordance with an embodiment of the present invention.

Figure lB is a cross-sectional view of the roller shown in Figure 1A
taking along lines lB-1B.

Figure 1C is an enlarged view of a portion of the roller shown in Figure.
1B.

Figures 2A and 2B are perspective and top views respectively of an example of pressure distribution along a single row of surface ports.

Figures 3A and 3B show a conveyorized, two axis cutting system that incorporates an example of the system described herein.

Figures 4A and 4B show an addressable vacuum roller having an array of surface ports in accordance with one example of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning now to the drawings, and first with reference to Figures 1A, 1B, and 1C, an apparatus according to an embodiment of the present invention is shown generally by reference numeral 101. There is provided a fully addressable vacuum/pressure roller. As used herein, the word "addressable"
refers to the identification of a location by an address or a name in order to facilitate information transfer. The use of an addressable control mechanism provides the ability to independently switch any single surface port (also referred to as aperture) to either vacuum, pressure or off (closed) without reference to the state of neighboring surface ports. Addressable control enables a vacuum roller to function with precision and specificity facilitating for example picking up and releasing work pieces having complex shapes from within a web or sheet.

Also, although the examples discussed herein include roller systems, it is envisioned that the addressable controls may be incorporated in other endless surfaces in circuitous motion applications including conveyorized belt systems generally. The use of addressable valves can benefit this entire class of moving systems that move in a loop.

Returning again to Figures 1A, 1B and 1C, a Vacuum roller 101 for conveying a web or sheet type material (Not Shown), comprises a rotatable roller 102 having an external surface 103. The rotatable roller 102 has a plurality of bores 104 there through, each of which bores 104 terminates at a surface aperture or port 105 in the external surface 103 of the rotatable roller 102. The surface ports 105 may preferably be disposed in a grid pattern of rows along the longitudinal direction of the rotatable roller 102 and rings (or columns) around its circumference. The rows are parallel to the axis of the roller and perpendicular to the direction of rotation of the roller.

A plurality of addressable valves 107 are in fluid communication with the corresponding plurality of bores 104. The plurality of addressable valves 107 is also in fluid communication with a vacuum source 108. This is achieved by having a vacuum manifold 109 inside a rotating roller. The vacuum manifold may be non-rotating, but is usually an axis-symmetric coaxial tube that rotates with the rotatable roller 102 to provide both a vacuum manifold and act as the primary structural support for the roller. A rotating slip joint is used at the end of the roller to allow fluid communication of the non-rotating vacuum source 108 with the rotating roller's vacuum manifold 109.

It is preferable in an alternative embodiment to provide, in addition to the vacuum source, a positive pressure source 110. The pressure source will enable positive air pressure to be used to discharge a piece of web material from the vacuum roller by progressively pushing the piece away as the web and roller advance. In this embodiment, the plurality of addressable valves 107 is also in fluid communication with a pressure source 110. This is achieved by having a pressure manifold 111 inside a rotating roller. The pressure manifold 111 may be non-rotating, but is usually an axis-symmetric coaxial tube that rotates with the rotatable roller 102 to provide both pressure and act as the primary support for the roller.

Vacuum and pressure are commuted from remote pumps (not shown) and compressors (not shown) to the rotating vacuum manifold 109 and pressure manifold 111 through rotating slip joints 112 located at the end of the roller shaft. This design provides for both angular and axial zoning of vacuum or pressure to the external surface 103 of the rotatable roller 102.

Figure 2A shows a representative pressure distribution diagram along a single row 206 of an addressable vacuum roller. The high pressure zones 201 show positive pressure intended to push away web portions that intersect row 206, the low pressure zones 202 show vacuum intended to retain web portions that intersect row 206.

Successive rows would generally have different pressure distribution profiles valving vacuum for example to ports that are in contact with portions of the web that are to retained by the roller, positive pressure to portions of the web that are to be removed from the roller, and closing the valve where no material is in contact with the roller (not shown).

Vacuum and pressure levels are shown on the diagrams with magnitudes of - 200 mb for the vacuum and + 200 mb for the pressure. However, these are shown as examples only. Appropriate levels would need to be investigated to be compatible with the web or sheet material to be manipulated and to allow the addressable vacuum roller to function as intended.

With reference to Figure 2A and 2B, the following example is by way of illustration only and is not intended to be limiting. A vacuum roller can be provided which is suitable for the handling of 48" wide plasticized vinyl webs for example 0.030" thick. The vacuum roller in the present example has an outside diameter of 10.0 inches and an active length of 48.0 inches. The axial port pitch of the surface ports is 2.0 inches which corresponds to 25 equally spaced surface apertures or ports along the roller's axis, the circumferential port pitch of the surface ports is about 1.6 inches, which corresponds to 20 equally spaced surface ports around the roller's circumference. The surface speed at which the web would travel while passing around the rotatable roller is 40.0 inches/second. With these specifications, the rotatable roller would have 500 surface ports. A programmable controller suitable for controlling the embodiment of the invention which selectively provides both vacuum and pressure in the rotatable roller would require 1000 output switches, 500 two state switches to select vacuum and 500 two state switches to select positive pressure. In the case of a vacuum only design, the programmable controller would require 500 two state outputs.

An alternative control system could provide for a switching matrix that utilizes a row and column multiplexer and a toggle valve at each surface port.
Such a multiplexed system would utilize momentary signal levels to switch valve states, requiring only 45 outputs - 25 for the axial addresses and 20 for the circumferential addresses.

Control method A means for addressably controlling the state of each of the plurality of valves is provided to selectively permit the fluid communication through a respective one of the bores between the vacuum source and a respective one of the surface apertures or ports. A large number of valves and associated ports is controlled by a valve control system such as a remote dedicated computer or programmable logic controller (PLC), or an embedded control system or combination thereof, with the required input/output hardware and software to perform the switch sequencing. The valve control system discussed by example herein is an electronic control system. Other valve control systems based on pneumatics or mechanical linkages or hybrid combinations of control systems may also be employed.

In the examples of web and sheet applications that follow, the X direction is along the long axis of the web also the direction of travel, the Y
direction is orthogonal to both the X axis and the web surface normal vector and the Z axis is normal to the surface of the web or sheet. Since these webs or sheets are generally flexible, the coordinate frame indicated here is relative to the surface of the web or sheet at any one point on its surface.

The control system software is limited to the function of 1) knowing the state of each of the valves (C=closed, V=vacuum and P= positive pressure), 2) knowing the x-position of the roller surface with respect to the x-position of the web and 3) being able to read a command file that describes the boundaries of the cut pieces in x, y coordinates relative to the web origin.

1) Knowing the state of each valve is most easily achieved by setting all of the valves into a known position prior to operation and then tracking the state changes invoked by the control system within the controller software.

2) The x-position of the roller surface with respect to the x-position of the web is achieved by either starting both at pre-determined positions or, at a time when the roller and web are not moving the operator can enter the current x-position of both the web and the roller into the controller software. After either of these initializations are completed an encoding device tracks the roller rotational position and the control system either tracks the web or sheet x-position by means of an encoding devise or the controller software calculates the web x-position based on the roller's rotational motion and estimates of web motion relative to the roller surface, if any.

A vision system could be utilized to scan and inspect the moving web upstream of the vacuum roller. This vision system would detect the positions of the cut lines and also detect flaws in the web material or in the cut lines, and construct the appropriate commands to allow the vacuum roller to position and switch the valve states so as to manipulate different portions of the web as intended, the cut pieces removed for further handling and flawed portions of the web discarded.

3) The control software performs a simple raster scan on the web and produces an image of the vacuum roller valve locations superimposed on an image of the pattern pieces. The vacuum roller valve state at each valve location is then determined and stored for retrieval when the vacuum roller is in motion.

As the vacuum roller rotates during operation, the control system determines the timing of the valve state transitions based on the x-position of the roller from the encoder and the stored valve states.

An example vacuum roller command file fragment required to operate the vacuum roller valve structure shown in FIGURE 4A and 4B to pick up a diamond shaped pattern piece out of a web is shown below.

row column - > Y axis a 6 C C C C C C C C V V V V V V V C C C C C C C C C
x 7 C C C C C C C V V V V V V V V V C C C C C C C C
i 8 C C C C C C C C V V V V V V V C C C C C C C C C
s 9 C C C C C C C C C V V V V V C C C C C C C C C C
C C C C C C C C C C V V V C C C C C C C C C C C

C C C C C C C C C C C C C C C C C C C C C C C C

Where C identifies a closed port, no fluid contact with either the vacuum or pressure manifold.

and V identifies surface port locations that are in. fluid communication with the vacuum manifold.

Control method - Example with multiplexed switch array For simplicity, the example described here is for a vacuum roller that is able to provide only vacuum ( port valve open ) or no pressure ( port valve closed) to any one of its surface ports.

Figure 4A shows an addressable vacuum roller 101 with an array of surface ports 105 in fluid communication with an addressable valve (not shown), the addressable valve can switch the port from fluid communication to a vacuum source (not shown) or to a closed state where no air flow is allowed to pass through the port.

As the roller 101 rotates, its rotational position is reported to the digital control computer 441 by an absolute digital encoder 440. The control computer compares the roller position to the position in a pre-calculated file of the valve states required to be switched along each row as that row passes a specific point in the roller's rotation, usually a point where the web or a cut piece is either entering or exiting tangent to the roller's surface.

The control computer transmits signals 411 to a column select switch bank 413 closing any number of normally open switches 405. At the appropriate time, the control computer transmits signals 412 to a row select switch bank 414 closing a single normally open switch 406.

The selected switch closures allow current to flow from the electrical power source 426 through the switch 405 out to the roller valve (not shown) in fluid communication with the surface port 105, the current then flows along the conductor 415, through the valve's solenoid actuator ( not shown ), then along conductor 416 to the row select switch 406 then to the electrical power source's ground 427.

The valve utilized here is of a toggle valve design - the current flowing through the valve's solenoid switches the surface port 105 into fluid communication with the vacuum source. When the electrical current is released, when either switch 405 or 406 are opened, the valve remains in the state where vacuum is ported through to the surface port 105. The port is closed when a mechanical link closes all ports along a specific row simultaneously (not shown ).

The multiplexed design described above allows the selective actuation of any valve such that the roller can apply selective vacuum force to any surface port as required.

Utilization - Vacuum Roller Arrangement To Separate Cut Pattern Pieces From A Passing Web Figures 3A and 3B show a conveyerized two axis cutting system as are commonly utilized to continuously cut web material from rolls where uncut roll goods iri web form 313 are supplied onto a flexible air permeable conveyer 321 in fluid communication with a vacuum manifold 315. The conveyer transports the material into a cutting zone where a 2 axis cutter carriage 317 cuts pattern piece boundaries 328 inside of the web 312. The web is comprised of pattern pieces 328 embedded within but severed from the surrounding scrap 329.

The web is advanced until it is under a first vacuum roller 300 of a traditional zoned vacuum roller design. This roller applies vacuum to it's surface starting at the position indicated by 331, the vacuum level is sufficient to pull the entire web off of the conveyer and advance the web to position 332 where roller 300 closes successive axial rows of surface ports as they pass position 332, so that the entire web can be picked up by the first addressable vacuum roller 301. Addressable vacuum roller 301 applies vacuum starting at position 332 to pull the entire web into intimate contact and away from roller 300.

Roller 301 then selectively switches only the surface ports that are adjacent to the pattern pieces at position 333 from vacuum to either closed or to positive pressure, the surface ports that are under the scrap portion of the web are maintained in fluid communication with the vacuum source to maintain intimate contact with roller 301. Addressable vacuum roller 302 applies selective vacuum to surface ports that are adjacent to the pattern pieces as they pass by position 333. As each row of addressable vacuum roller 302 passes location 334, all surface ports along that row are closed such that pattern pieces 328 in contact with roller 302 transfer to a conveyer removal system 340. As each row of vacuum roller 301 passes position 335 all surface ports along that row are closed, releasing the scrap portions of the web 329 onto an appropriate scrap removal system 350.

The apparatus described above comprises an effective system to separate cut pattern pieces from a web and deposit the pattern pieces onto an appropriate take-away system while also sending the scrap to an appropriate location. A more advanced system employing a greater number of addressable vacuum rollers would allow the separation of multiple layers of pattern pieces and scrap. Such a system would have multiple arrangements of addressable vacuum rollers, each such arrangement would be of the same general configuration as described above and presented in Figure 3A and Figure 3B.
Additionally, while the web is shown moving across the roller, it is also possible for the web to be stationary and have the roller move across the web. Still further, they may both move relative to each other at the same time.

Utilization - Differential Pressure To Aid An Addressable Process On A Web Further, the addressable vacuum roller disclosed in the present invention may be utilized to apply selective controlled normal force to portions of a web where such variable pressure across and within a web is intended to even out the tensions of a web with non-uniform elastic properties such as a web with embroidered emblems embedded within or a web or sheet with non-uniform structural reinforcement.

These and other objects, aspects and features of the present invention may be realized by the provision of a vacuum roller. As will be appreciated by one of ordinary skill in the art, an apparatus according to the invention may be suitable for use in any field or industry requiring selecting and removing pattern pieces that have been severed or cut from a web or sheet of flexible material. Accordingly, the present invention should not be viewed as limited to any particular use or use in any particular industry. While the foregoing describes what are considered to be preferred embodiments of the present invention, it is understood that various modifications may be made thereto and that the invention may be implemented in various forms and embodiments, and that it may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim all such modifications and variations which fall within the true scope of the invention.

Claims (13)

1. An endless surface in circuitous motion system comprising:

an outer surface having a plurality of apertures configured in the surface;

a corresponding plurality of valves wherein each aperture has a valve in fluid communication therewith, and further wherein each valve is in fluid communication with at least one of a vacuum source and a positive pressure source; and a valve control system connected to each valve, wherein, each individual valve may be independently switched by the valve control system between being in a state of switched closed, and switched to vacuum or switched to positive pressure without reference to the state of any other valve.

2. An endless surface in circuitous motion system as described in claim 1, wherein each valve is in fluid communication with both a vacuum source and a positive pressure source, and wherein each valve may be independently switched by the valve control system between being in a state of switched closed, switched to vacuum, and switched to positive pressure.

3. An endless surface in circuitous motion system as described in claim 1, wherein the outer surface is the outer surface of a rotating roller.

4. An endless surface in circuitous motion system as described in claim 1, wherein the electronic control system is either a dedicated computer or a programmable logic controller.

5. An endless surface in circuitous motion system as described in claim 3, wherein the vacuum source is a vacuum manifold inside the rotating roller.

6. An endless surface in circuitous motion system as described in claim 3, wherein the positive pressure source is a positive pressure manifold inside the rotating roller.

7. An endless surface in circuitous motion system as described in claim 1, wherein the valve control system is remote from the endless surface.

8. An endless surface in circuitous motion system as described in claim 1, wherein the valve control system is embedded in the endless surface.

9. A method of separating pieces of flexible material cut from a web comprising the steps of:

providing a vacuum roller comprising an outer surface and a plurality of apertures configured in the surface, a corresponding plurality of valves wherein each aperture has a valve in fluid communication therewith, and further wherein each valve is in further communication with a vacuum source;

providing a valve control system connected to each valve, wherein each individual valve may be independently switched by the valve control system between being in a state of switched closed and switched to vacuum without reference to the state of any other valve;

Moving the web across the vacuum roller or moving the vacuum roller across the web, wherein the roller is disposed across the direction of relative motion of the web and vacuum roller; and selectively controlling the valves in the vacuum roller to attract or not attract portions of the web to the surface of the roller.

10. A method as described in claim 9, further comprising:

providing a positive pressure source also in fluid connection with each valve, wherein each valve may also alternatively be switched to a state of switched to positive pressure.

11. A method as described in claim 9, further comprising:

providing a plurality of vacuum rollers disposed across the direction of relative motion of the web and vacuum roller, and moving the web across the plurality of rollers or moving the rollers across the web, and selectively controlling the valves in the plurality of rollers to attract or not attract portions of the web to the respective surfaces of the respective rollers.

12. A method as described in claim 9, wherein the apertures are generally uniformly disposed over the surface of the roller.

13. An endless surface in circuitous motion system as described in claim 1, wherein the apertures are generally uniformly disposed over the surface of the roller.