Abstract:
A wire feeding apparatus is disclosed. The wire feeding apparatus includes a rotable drive shaft, a servo motor in driving relationship with the drive shaft and one or more feed modules. Each feed module is selectively engaged with the drive shaft through the use of a linear actuator. When the linear actuator is engaged, each feed module is driven by the drive shaft such that wire is either fed or retracted.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   None. 
   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not Applicable. 
   APPENDIX 
   Not Applicable. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to a wire feeding device for a bulk material baler, and more particularly to a device for feeding wires individually selected from a plurality of wires. 
   2. Related Art 
   Wire baling of bulk materials benefits from increased speed and reduced materials cost through automation. Bulk materials include fibrous bulk materials such as cotton and nylon. Fibrous materials are commonly formed into bales by simultaneous compression and binding. There is a continuing need in the automated baling art to improve the efficiency, reliability and accuracy of the bale binding process. 
   Baling wire performance requirements vary depending upon the bulk material being baled. Such requirements range from industry standard specifications to general operational parameters, such as minimum speeds required for profitability. The Cotton Council issues standard baling constraints specifying particular ranges for the length of wire around the bale and the tension that the wire must withstand. 
   Current automated baling machines use an articulated track to guide wire around bales of bulk material, while that bale is under compression. Part of the wire guide track in current automated balers must be removable to a second position after the ends of the baling wire have been tied together, in order to allow ejection of the bale and insertion into the baler of the next unit of material for baling. Material to be baled is typically introduced into the automatic baler under vertical compression. Typical pressures for an industry standard 500 pound, 20 by 54 inch bale are in excess of 300 tons. Horizontal plates called follower blocks apply compression through platens which contact the surface of the cotton or other material being compressed. The platens incorporate slots which run laterally to the longitudinal axis of the bale. The Industry Standard number of binding wires for cotton bales is six. Accordingly, there are six slots in the platens. These allow the baling wire to be wrapped around the bale while it is still under compression. The lateral slots have lateral channels behind them for insertion of wire guide tracks in both the upper and lower platens in automatic balers. 
   It is not uncommon for a wire being looped around the bulk material to bind up in the track or otherwise misfeed. In this case, it is necessary to remove the bound up wire and retie the bale. Presently, there exists no easy or convenient method to re-feed the wire around the bale. Either the wire can be looped manually which presents some hazard to the operator or alternatively the tied wires may be cut and the process begun again. There remains a need for an automatic baling apparatus that can correct mis-feeding errors. 
   Moreover, in order to loop baling wire around bulk material to be baled, release it from a guide track and knot the ends, tension must be generated in the wire. Likewise, in order to properly knot the ends of the wire, tension must be maintained in the twisting procedure that generates the knot. These tensions must be maintained within prescribed ranges to optimize efficiency and to produce a final bale compliant with industry standards. 
   Typically, tension is created in the wire by reversing the wire feed mechanism. In other words, the wire feed mechanism reverses, pulling the wire out of the track and drawing it tight against the bail. In the case of a misfeed, it is necessary to not only loop a single wire around the bale, but it is also necessary to tension the wire. There remains a need in the art for a simple but effective apparatus for feeding and tensioning a single wire loop. 
   U.S. Pat. No. 3,119,536 issued to Berkeley on Jan. 28, 1964 discloses a wire feeding apparatus. The device includes a constantly rotating shaft, a first gear connected to the rotating shaft, and a second gear which is selectively engaged with the first gear. The second gear is mounted on a square bar and is biased upwardly away from the first rotating gear. The Berkeley device uses pivot arms that push the second gear downwardly to overcome the bias and engage with the first gear such that wire is fed. The Berkeley device is relatively complex and expensive due to the number of components it requires. Moreover, the Berkeley device is inefficient in that it utilizes a constantly rotating shaft. 
   Other prior art devices achieve selective drive of separate wire feed devices by separately powering each of three or more wire feed devices with an individually dedicated servo motor. While this achieves selective engagement of individual wire feeders, it clearly multiplies the expense by using multiple servo motors. There is a need in the art for a device with selective engagability capabilities that is less expensive. 
   There remains a need in the art for an economical wire feeding apparatus for feeding and tensioning wire that is simple, reliable and inexpensive. 
   SUMMARY OF THE INVENTION 
   It is in view of the above problems that the present invention was developed. The invention is a wire feeding apparatus for individually and selectively feeding a plurality of wires with a single motor. The motor rotates a drive shaft. Each wire feeder includes a fixed gear driven by the drive shaft and a pivotable gear that is adapted to move toward and away from the fixed gear. A feed wheel is connected to each gear. As the two gears approach one another and become engaged, the feed wheels frictionally engage a wire, thereby feeding it between them. 
   In one embodiment, the pivotable gear is mounted on an eccentric and the eccentric is rotated by a linear actuator via a pivotable arm. The linear actuator extends linearly and rotates the eccentric. Rotation of the eccentric causes the pivotable gear to move toward or away from the fixed gear. As such, the linear actuator can be used to selectively control when the wire is fed through each individual wire feeder. 
   Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and form a part of the specification, illustrate the embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings: 
       FIG. 1  is a perspective view of the wire feeding apparatus; 
       FIG. 2  is a rear perspective view of the wire feeding apparatus; 
       FIG. 3  is an exploded view of the wire feeding apparatus; 
       FIG. 4  is a perspective view of a cotton baler; 
       FIG. 5  is a perspective view of the carriage unit; 
       FIG. 6  is an exploded view of a motor drive gear box and drive shaft; 
       FIG. 7  is a schematic view of a control system; 
       FIG. 8  is a side view of the carriage unit illustrating the linear actuator in a first position; and 
       FIG. 9  is a side view of the carriage unit illustrating the linear actuator in a second position. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the accompanying drawings in which like reference numbers indicate like elements,  FIGS. 1 and 2  illustrate a wire feeding apparatus  10 . The wire feeding apparatus  10  includes a base plate  12 , a first gear  14 , a first feed wheel  16 , a second gear  18 , and a second feed wheel  20 . The wire feeding apparatus  10  also includes wire guides  26 . The wire guides  26  direct the wire into and away from the feed wheels  16 ,  20 . 
   The gears  14 ,  18  have a ratio in the range of about 1:1 to about 2:1. As an example, each gear  14 ,  18  may have 42 teeth. In the depicted embodiment, the gears  14 ,  18  are made of crucible steel, and the wheels  16 ,  20  are made from tool steel. In some embodiments, the wheels  16 ,  20  are also black oxide coated. The first feed wheel  16  is connected to the first gear  14 , and the second feed wheel  20  is connected to the second gear  18 . 
   In the depicted embodiments, each wheel  16 ,  20  is circumscribed by three grooves  60 . Those skilled in the art will understand that a greater or lesser number of grooves may be used. The grooves  60  are dimensioned to accept a particular size of wire. As an example only, the grooves  60  may be dimensioned to accept a 10 gauge wire. The grooves  60  on each wheel  16 ,  20  are aligned with the grooves on the other wheel. 
   The first gear  14  is pivotable such that it can be moved toward and away from the second gear  18 . As the first gear  14  is pivoted towards the second gear  18 , the two gears  14 ,  18  intermesh such that a wire is captured between the grooves  60  of the feed wheels  16 ,  20 , thereby feeding the wire. 
   The wire feeding apparatus  10  also includes an eccentric  36 , a pivotable arm  22 , and a linear actuator  30 . As used herein, the term “eccentric” means a component having an eccentric axis of revolution so that the component can impart reciprocating motion. In the depicted embodiment, the eccentric  36  is a cylinder with a hole  37  offset from the center of the cylinder. The hole  37  is adapted to receive a first spindle  32 , and the eccentric  36  rotates about first spindle  32  located in the hole  37 . In the depicted embodiment, the first gear  14  rotates about the eccentric  36 . 
   The pivotable arm  22  is operatively connected to the first gear  14  such that as the pivotable arm  22  is pivoted, the first gear  14  moves toward or away from the second gear  18 . In the depicted embodiment, the eccentric  36  includes a slot  62  that receives the pivotable arm  22  and moves with the pivotable arm  22 . As such, when the pivotable arm  22  moves, the eccentric  36  rotates about the first spindle  32 . 
   The linear actuator  30  pivots the pivotable arm  22 . In the depicted embodiment, the linear actuator  30  is an air cylinder and includes fittings  28  for receiving a fluid, such as air. However, other types of actuators, a hydraulic cylinder for example, may be used. The linear actuator  30  not only provides a simple mechanism for selectively engaging the feed wheels, but also the linear actuator  30  compensates for wear in the grooves  60  to ensure that the wire is adequately engaged. In other words, as grooves  60  wear out, to a limited extent, the linear actuator  30  decreases the distance between the feed wheels  16 ,  20 . When the linear actuator  30  moves the pivotable arm  22 , the pivotable arm  22  rotates the eccentric  36 . Thus, actuation of the linear actuator  30  rotates the eccentric  36  and moves the first gear  14  toward or away from the second gear  18 . 
     FIG. 3  illustrates an exploded view of the wire feeding apparatus  10 . The wire feeding apparatus  10  includes a connecting arm  24 , the feed wheels  16 ,  20 , a grease fitting  58 , an external bearing  39 , a thrust washer  51 , a first grease seal  40 , a spherical roller bearing  41 , a second grease seal  52 , the eccentric  36 , a retaining ring  43 , a prelubricated bearing  55 , a needle bearing  53 , a sensor actuator  46 , an external retaining ring  50 , the first gear  14 , the pivotable arm  22 , the linear actuator  30 , the first spindle  32 , a second spindle  34 , and the base plate  12 . In some embodiments, the wire feed apparatus  10  also includes a spacer  38 . As a groove  60  wears out, the spacer  38  may be inserted between the wheel  16 ,  20  and the gear  14 ,  18 . For example, if the wheel  16 ,  20  has two grooves  60  and the first groove wears out, the spacer may be inserted to select the second groove. The connecting arm  24  connects the first spindle  32  to the second spindle  34  thereby providing additional stability. 
   In the depicted embodiment, the linear actuator  30  includes a front mounting swivel flange  47 , tubing  48  connected to the fittings  28 , and a rod clevis  49 . The front mounting swivel  47  is used to mount the linear actuator  30 . The tubing  48  is used to supply fluid, compressed air for example, to the linear actuator  30 . The rod clevis  49  is adapted to receive the pivotable arm  22 . 
   The first and second spindles  32 ,  34  are mounted to the base plate  12 . Bearings  41  are mounted on the second spindle  34 , and the second gear  18  mounts on the bearings  41 . The prelubricated bearing  55  mounts on the first spindle  32 , and the eccentric  36  mounts onto the prelubricated bearing  55 . In the depicted embodiment, the hole  37  of the eccentric  36  receives the prelubricated bearing  55 . The prelubricated bearing  55  mounts onto the first spindle  32 , and the eccentric  36  pivots about the first spindle  32 . 
   The first gear  14  is mounted on the eccentric  36 . As such, when the eccentric  36  is rotated or pivoted about the first spindle  32 , the first gear  14  travels an arcuate path. As assembled, when the eccentric  36  is pivoted about the first spindle  32 , the first gear  14  pivots toward or away from the second gear  18 . As such, there is a clearance between the first feed wheel  16  and the second feed wheel  20  when the first gear  14  is moved away from the second gear  18 . In the depicted embodiment, there is a clearance of 0.140 inches (3.6 mm). The clearance is sufficient to prevent the frictional driving of any wire between the channels  60  of wheels  16 ,  20 . 
   Referring now the  FIG. 4  and as an example only, the wire feeding apparatus  10  may be used within a cotton baling machine deployed in operative cooperation with a cotton press  100 . The cotton baling machine includes, among other things, a carriage unit  110 . In the depicted embodiment, the carriage unit  110  includes a servo motor  112 , a gear box  114 , and a plurality of wire feeding apparatus  200 . 
     FIG. 5  illustrates a more detailed view of the carriage unit  110 . In  FIG. 5 , the gear box is omitted for clarity. The carriage unit  110  includes the wire feeding apparatus  200 . In the depicted embodiment, there are three wire feeding apparatuses  200 . Those skilled in the art will understand that a greater or lesser number of wire feeding apparatus  200  may be used. For example, there may be as few as one feeding apparatus  200  and as many as eight wire feeding apparatuses  200 . Each wire feeding apparatus  200  includes a linear actuator  230 . The carriage unit  110  also includes the servo motor  112  and a drive shaft  116 . 
     FIG. 6  illustrates the servo motor  112 , the gear box  114 , and the drive shaft  116 . The drive shaft  116  includes spur gears  120  and mounting flanges  118 . The mounting flanges  118  support and locate the drive shaft  116 . Each spur gear  120  mates with a corresponding second gear  218  (best seen in  FIG. 5 ) and is sized accordingly. In the depicted embodiment, the spur gears  120  each have 24 teeth. The ratio between the second gears  218  and the spur gears  120  is about 1:1 to about 2:1. In the depicted embodiment, the second gears  218  and the spur gears  120  have a ratio of 1.75:1. A first mounting sleeve  124  is used to mount the motor  112  to the gear box  114 . A second mounting sleeve  122  is used to mount the gear box to the carriage unit  110 . The gearbox  114  is a gear reducer with a gear ratio in the range of about 5:1 to about 7:1. In the depicted embodiment, the gear box  114  has a gear ratio of 5.955:1. 
   A control system  70  is illustrated in  FIG. 7 . The control system  70  includes a control module  72 . Components for appropriate control systems  70  are described in U.S. Pat. No. 6,633,798 issued to Stamps et al. on Sep. 30, 2003, which is incorporated herein by reference. They may include, for example, PLCs. The control module  72  is operatively connected to linear actuators  230   a ,  230   b ,  230   c , and to the servo motor  112 . The control module  72  and the linear actuators  230  may be electrically connected such that electrical signals from the control module  72  actuate and de-actuate actuators  230 . The control module  72  may receive input directly from an operator or instructions from another machine. The control module  72  selectively engages the linear actuators  230  and the servo motor  112 . In one example, the control module  72  engages all three linear actuators  230   a ,  230   b ,  230   c  and subsequently engages the servo motor  112 . In another example, the control module  72  engages only one of the linear actuators, such as  230   b , and subsequently engages the servo motor  112 . In yet another example, the control module  72  engages two of the linear actuators, such as  230   a  and  230   c , and subsequently engages the servo motor  112 . In this manner, the wire feeding apparatus  200  can be selectively engaged. For example, if a wire mis-feeds in a particular track, the particular wire feeding apparatus  200  can be singularly engaged to re-feed the wire. 
     FIGS. 8 and 9  illustrate operation of the linear solenoid  230 . In  FIG. 8 , the first gear  214  is shown in a first position away from the second gear  218 . In the first position, the wire is not fed because there is a clearance between the first gear  214  and the second gear  218 . In  FIG. 9  however, the linear actuator  230  has moved the first gear  214  to a second position. In this second position, there is very little clearance between the first feeding wheel and the second feeding wheel. As such, the feeding wheels frictionally engage the wire and feed it around the bale. 
   In  FIG. 8 , the drive shaft  210  is rotating which in turns rotates the second gear  218 . However, because there is a clearance between the first gear  214  and second gear  218 , the first gear  214  does not rotate. 
   In the engaged, driving, second position shown in  FIG. 9 , the drive shaft  210  rotates, which in turn rotates the second gear  218 . Because the first gear  214  is now in contact with the second gear  218 , it also rotates. The two gears  214 ,  218  rotate in opposite directions and pull or push the wire depending upon the rotational direction of the servo motor  112 . The drive shaft  210  can be rotated in either direction. As such, the wire can be moved in either direction. This is significant because in the cotton baler  100 , wire must first be fed around the bale, but it must then be reversed and pulled back to tension the wire out of its guide tracks and then draw the wire taut against the bale. 
   A method of assembling a wire feeding apparatus is provided. The method includes the steps of: providing a feed module base plate; connecting a first spindle to the base plate; connecting a second spindle to the base plate; mounting an eccentric on the first spindle; connecting a first gear to the eccentric; connecting a first feed wheel to the first gear; mounting a second gear on the second spindle; connecting a second feed wheel to the second gear; and connecting a pivotable arm to the eccentric. The method further includes the step of connecting an actuator to said pivotable arm. The actuator is deployed to mediate the travel of one of the wheels to and from an engaged position that feeds wire. 
   There is also provided a method of controlling a wire feeding apparatus. The method includes the steps of: providing a fixed gear connected to a first feed wheel and a pivotable gear connected to a second feed wheel, the pivotable gear mounted for movement toward and away from the fixed gear; providing a pivot arm connected to the pivotable gear and a linear actuator connected to the pivot arm; engaging the linear actuator; moving the pivotable gear toward the fixed gear; frictionally engaging a wire with the first feed wheel and the second feed wheel; engaging a servo motor; and rotating a drive shaft connected to the fixed gear. In some embodiments, the method further includes the step of selecting at least one other linear actuator for engagement. 
   In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained. 
   The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. 
   As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents.