Abstract:
A follower apparatus mounted on a track running parallel to an axis of rotation of a spool. The apparatus has a base with a roller mounted thereon and having an axis of rotation parallel to the rotational axis of the spool, the roller providing support and guidance to the material being wound. A pulley is rotatably mounted to receive material from the roller and redirect the direction of material traveled. Light beams and detection apparatus are positioned to detect material excursions to pre-determined off center portions of the roller. The follower positioning apparatus responds to signals detecting the material by repositioning the follower to place the material back on to a center zone of the roller.

Description:
[0001]    This application claims priority from provisional U.S. patent application Ser. No. 60/412,238 filed Sep. 19, 2002 and provisional U.S. patent application Ser. No. 60/415,613 filed Oct. 1, 2002. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The present invention relates to an apparatus for unwinding fiber from a spool, and most particularly to a fiber spooling machine that uses an optical sensing method to detect the fiber position as it is unwound from a spinning spool and automatically positions itself to be aligned with the fiber.  
           [0004]    2. Description of the Prior Art  
           [0005]    In a fiber (or wire) spooling machine, which unwinds the fiber from a payout spool and rewinds it onto a take-up spool, a device that tracks the position of the fiber as it comes off the payout spool is often required. This device is referred to as a follower and ensures that the path of the fiber coming off the spool is perpendicular with respect to the spool&#39;s axis of rotation. This is advantageous for preventing fiber (or wire) damage, which could occur if the angle between the fiber path and the spool axis becomes too large, as the fiber would then be dragged over adjacent wraps.  
           [0006]    On a system that only unwound spools with a known and consistent fiber wind pitch and known and consistent spool dimensions, a spooling machine design would be trivial. A follower on such a system could consist of a spinning pulley mounted on a linear slide that would move back and forth, parallel to the spool axis at a known distance and at the specified pitch. Wound spools with known and consistent fiber winding pitch and spool dimensions are rarely the case. Many variables can complicate the required operation of a follower. First, the fiber pitch often varies between spools and on a single spool. Spool flange dimensions vary due to wear or manufacturing tolerances. The follower linear axis is also often set up incorrectly with respect to the position of the spools. In order to compensate for these variations the follower would need to adaptively position itself based on the actual position and angle of the fiber as it comes off the payout spool.  
         SUMMARY  
         [0007]    It is an object of the present invention to provide an improved apparatus for detecting the position of material unwinding from a spool using an optical sensing method.  
           [0008]    It is a further object of the present invention to provide a follower apparatus that guides the material unwinding from a spool along a desired path utilizing a roller.  
           [0009]    It is a still further object of the present invention to provide a follower apparatus that enables the position of material to be accurately tracked at any line speed with any pitch regardless of the variations in the spool without damaging the fiber or losing its position.  
           [0010]    Briefly, a preferred embodiment of the present invention includes a follower apparatus mounted on a track running parallel to an axis of rotation of a spool. The apparatus has a base, with a roller mounted thereon having an axis of rotation parallel to the rotational axis of the spool, the roller providing support and guidance to the material being unwound from the spool. A pulley is rotatably mounted to receive material from the roller and redirect the direction of material travel. Light beam and detection apparatus detect when the material moves out of a selected/center zone of the roller and provide a corresponding signal. A follower positioning apparatus responds to the signal by repositioning the follower to place the material back into the center zone of the roller. 
       
    
    
     IN THE DRAWING  
       [0011]    [0011]FIG. 1 shows a follower apparatus according to the present invention guiding material being unwound from a spool;  
         [0012]    [0012]FIG. 2 is an enlarged view of the follower apparatus of FIG. 1;  
         [0013]    [0013]FIG. 3 is a side planar view of the follower apparatus and a spool;  
         [0014]    [0014]FIG. 4 is an illustration of angled sensor apparatus;  
         [0015]    [0015]FIG. 5A is a side planar view of the follower, and illustrates an alternate placement of sensor apparatus;  
         [0016]    [0016]FIG. 5B further illustrates the alternate sensor apparatus of FIG. 5A;  
         [0017]    [0017]FIG. 6A illustrates sensor apparatus with multiple reflective emitter-detectors;  
         [0018]    [0018]FIG. 6B illustrates sensor apparatus using transmissive detection;  
         [0019]    [0019]FIG. 6C shows a sensor apparatus using a columator;  
         [0020]    [0020]FIG. 7 illustrates a pulley mounted with its axis parallel to the axis of the roller;  
         [0021]    [0021]FIG. 8 shows more detail of a follower module with the pulley oriented as shown in FIG. 7;  
         [0022]    [0022]FIG. 9A is a perspective view showing a material position sensor apparatus based on a pulley angle measurement;  
         [0023]    [0023]FIG. 9B is a drawing further illustrating the angle measurement of FIG. 9A; and  
         [0024]    [0024]FIG. 10 illustrates an embodiment wherein the payout spool position is adjusted instead of the follower module position. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0025]    [0025]FIG. 1 illustrates a follower apparatus  10  according to the present invention. The apparatus  10  includes a material follower module  12 , a track  14  and a controller apparatus  16 . The term “motorized” will be used in the present specification and refers to any method providing movement of the module  12  of FIG. 1, or of the spool module  144  of FIG. 10 which will be described in the following text of the specification. For example, the apparatus could be a piston attached to the module  12 , and wherein the motor for moving the piston could be remotely located from the module itself. The module  12  or spool module  144  could also be mounted on an articulating arm propelled by a motor. The present invention is intended to include the various alternative constructions that will be apparent to those skilled in the art upon reading the present disclosure.  
         [0026]    Referring again to the embodiment of FIG. 1, the follower module  12  includes a freely spinning roller  18 , (mounted on a base  20 ) with an axis of rotation  22  of the roller  18  parallel to the axis of rotation  24  of a payout spool  26 . The material  28  such as a fiber, etc. is redirected by the roller  18  to a pulley  30 , that can be mounted with its axis of rotation  32  at an angle to the roller axis  22 . Embodiments with the pulley  30  axis  32  perpendicular and embodiments with the axis  32  parallel to the roller  18  axis  22  will be described in detail in the following text, but the present invention also includes other angles. The material  28  is redirected by the pulley  30  and runs to the next pulley or other apparatus in the system. If the pulley  30  axis  32  is perpendicular to the roller axis  22 , the pulley  30  is aligned such that the plane it rotates in, which is perpendicular to the axis of rotation  32 , and the plane that the fiber is guided along, is tangent to the surface of the roller  18 . This ensures that the material  28  will not rub on the pulley walls. The material  28  can run anywhere along the length of the roller  18  depending on the position of the follower  12  with respect to where the fiber unwraps from the spool  26 . Thus, the angle  34  (FIG. 2) of the segment  36  of material  28  between the roller  18  and pulley  30  changes depending on the follower  12  position relative to the point  38  that the fiber leaves the payout spool  26 . FIGS. 3, 4 and  5  show two fiber presence sensors  40  and  42 , which detect the presence of the material  28  in side zones  46  and  48  on the roller  18  by emitting a light beam and detecting light reflected when the material  28  moves out of a selected zone  44 , which will also be referred to as a center zone, and into the path of the light beam. The two sensors  40  or  42  detect in side zones  46  and  48 , leaving a “deadband” center zone  44  in the center of the roller  18 . Neither sensor  40  or  42  can detect the material  28  in the center zone  44 . When the fiber moves out of the center zone  44 , far enough from the center to either side zone  46  or  48 , the corresponding sensor  40  or  42  will detect its presence, sending a signal to the controller  16  which will direct motorized apparatus associated with the module  12  and track  14  to make an appropriate adjustment in the module  12  along the track  14  to return the material  28  to the center zone  44 . The material  28  is prevented from exiting the side zones  46  or  48  by physical stops  50  and  52 , that allow the material  28  to bend around the edge of the stop ( 50  or  52 ) without breaking. During normal operation, the material  28  will never contact the stops  50  or  52 , but they are provided to prevent the material  28  from coming off the roller in case of a failure of one or more sensors  40  or  42 , or a poorly wound payout spool  26  with abnormally large material pitch variations. Although the text and figures of the drawing show a center zone  44  and two side zones  46  and  48 , the present invention includes any number of zones. The specification also describes only two sensors  40  and  42 , but as with the number of zones, these are given by example, and the present invention also includes any number of sensors arranged for sensing the presence of the fiber/material in any number of zones. The three zone model described in detail is a practical embodiment of the present invention that minimizes the number of elements.  
         [0027]    The sensors  40  and  42  as shown in FIGS.  1 - 5 A are tilted, with sensor  40  directing a light beam upward from a horizontal direction (FIG. 5A), and sensor  42  directing a light beam downward. The reason for the angles is to direct the laser beams so that they will intersect the material  28  at a direction orthogonal to the material direction of travel. This assures that an optimum signal is reflected back from material to a light detector of the sensor ( 40 ,  42 ). The need for the angled sensors is due to the convenient positioning of the sensors on the base  20 , requiring them as shown being displaced at an oblique angle to the direction of the roller  18  axis  22 . This arrangement of angles is illustrated in FIG. 4, which is a view looking in a direction orthogonal to the plane of the material  28  and pulley  30 . Looking at the sensors  40  and  42  from the view of FIG. 4 places the sensors towards the viewer. This is more clearly illustrated in reference to the perspective views of FIGS. 1 and 2. Sensor  40  is shown directed upward at an angle  54 , and sensor  42  downward at an angle  56 . Because the sensors are located off the axis  22 , towards the viewer, the beam areas  58  and  60  in the planar view of FIG. 4 appear elliptical with widths  62  and  64 .  
         [0028]    In operation, as the material  28  moves through the beam width  62 , a portion of the beam is reflected off of the material, traveling back to the sensor  40  where the reflected signal is detected and gives indication to the controller  16  to move the position of the module  12  to bring the material back into the center zone  44 . A similar operation applies when the material moves into the width  64  of beam  60 .  
         [0029]    Alternatively, an apparatus can be constructed extending for example from the base  20 , to position the sensors so as to direct the light beams orthogonal to the plane in which the material  28  moves in the space between the pulley  30  and the roller  18 , so that when the material intersects the sensor light beam, the beam is orthogonal to the material regardless of the position of the material  28  on the roller  18 .  
         [0030]    Referring to FIG. 5A, which is an enlargement of the view of portion B of FIG. 3, the dashed lines  66  illustrate sensors  68  and  70  in the alternative position as described above. FIG. 5B illustrates the arrangement of sensor apparatus  68  and  70  of FIG. 5A as would be observed from a top view indicated by direction arrow “A” in FIG. 5A. The material  28  is shown in both side zones  46  and  48 . Referring to FIG. 6A, whether the sensors are positioned as sensors  40  and  42 , or as sensors  68  and  70 , a still further alternative sensor apparatus can be used that includes a first sensor apparatus for zone  46  and a second sensor apparatus for zone  48 , and in this case each sensor apparatus can include a plurality of sensors, and can be mounted to provide a series of beams on each side of the center zone  44 . FIG. 6A shows a plurality of beams  72  on one side and a plurality of beams  74  on the other side. Each of the corresponding plurality of sensors can provide a signal to the controller  16  when the sensor&#39;s beam is reflected by the material. The controller therefore receives information as to the location of the material in the zones  46  and  48  outside the center zone  44 , and the controller  16  can be programmed to adjust the follower position accordingly to bring the material  28  back to the center zone  44 .  
         [0031]    [0031]FIG. 6B illustrates a further alternative embodiment of sensor apparatus wherein a light source  76  is positioned on one side of material  28 , and includes one or more light emitters providing corresponding one or more beams  78 . A plurality of light sensors  80  are placed on an opposite side of the material  28 . When the material  28  intercepts one of the beams  78 , it causes a reduction in light arriving at the corresponding one of sensors  80 , and this change in detected signal is received by a controller  82  via line  84 . The controller  82  then directs the follower to reposition the module  12  so as to center the material  28  on the roller  18 . A still further embodiment is indicated in FIG. 6C wherein a bank  86  of a plurality of emitters is placed on one side of material  28  with a light collimator in order to provide a field  88  of collimated light shining in the direction shown. An array of light sensors  90  is placed on the opposite side of material  28 , feeding signals to sensor electronics  92  providing detected outputs  94  to a controller. In this case, the sensor electronics can be configured to send a signal to the controller proportional to its position for correcting the follower module  12  position.  
         [0032]    Referring again to FIG. 1, the pulley  30  as mentioned above can also be mounted with its axis of rotation  32  parallel with the axis of rotation  22  of the roller  18 . The orientation of the pulley  30  and roller  18  in this case is shown in FIG. 7, illustrating the material  28  advancing from a payout spool as indicated by arrow  96 . FIG. 7 simply illustrates the fact that in order to keep the material  28  from rubbing on the walls  98  and  100  of the pulley  30  when the material  28  becomes displaced from the center line  102  of the pulley  30 , the angle  104  of the pulley  30  walls  98  and  100  needs to exceed the angle  106  of the material  28 . A follower module  108 , with the pulley  30  mounted is illustrated in FIG. 8.  
         [0033]    [0033]FIG. 9A shows an alternative embodiment wherein the pulley  30  is mounted in the orientation as in FIG. 8, but is additionally mounted to a rotational member  110  providing rotation of the pulley around axis  112 . As the material  28  moves into one of the side areas  114  or  116 , the material causes pulley  30  to rotate about the axis  112  to keep the pulley in line with the material  28  direction. An encoder apparatus  118 , symbolically illustrated, can be incorporated to send a signal to a controller  120  via line  136  that is indicative of an angle of rotation of the apparatus  110  and pulley  30  around axis  112 .. The controller  120  can then respond by directing the follower  124  via line  126  to adjust the follower module  128  position along track  129  so as to bring the material  28  back to the center zone of the roller  18 . This angle detection method provides an enhanced sensitivity due to a larger angular movement of the pulley  30 , for example than in a system that measures the angle of the material  28  between the spool  26  (FIG. 1) and the follower  10 . The enhanced angle of rotation of the pulley  30  is due to the distance between the pulley  30  and roller  18  being shorter than the practical distance between the spool  26  and follower  10 . FIG. 9B is a planar view illustrating a severe rotation of the pulley  30  when the material  28  is off to one side of the roller  18 . The encoder  118  provides a measure of the angle  130 .  
         [0034]    A further alternate embodiment of the present invention is illustrated in FIG. 10 wherein a material guide module  132  similar to the follower module of FIG. 1 is mounted in a fixed position. The detection of the fiber  28  position on the roller  18  is the same as described above in reference to module  12  of FIG. 1, etc. and may include any of the material detection methods as described above. When the fiber is detected in one of the side zones  134  or  136 , similar to zones  46  and  48  of FIG. 1, the detected signal is received by a controller  138  that responds by outputting a corrective signal on bus  140  to a motorized spool positioning assembly  142 . The assembly  142  includes a spool module  144  and track apparatus  146 . The assembly  142  responds to the corrective signal on bus  140  by moving the module  144  so as to reposition a spool  148  in a direction to bring the fiber  28  back into the center zone  150  between side zones  134  and  136 .  
         [0035]    Although the present invention has been described above in terms of a specific embodiment, it is anticipated that alterations and modifications thereof will no doubt become apparent to those skilled in the art. It is therefore intended that the following claims be interpreted as covering all such alterations and modifications as fall within the true spirit and scope of the invention.