Abstract:
Coil winding machine including, among other things, a spindle head assembly. The spindle head assembly includes a non-rotatable spindle nose, a rotatable flywheel, and an applicator head mounted to the flywheel. Core wire travels through the spindle nose and the applicator head wraps coil wire around the core wire.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     None.  
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
       [0002]     Not Applicable.  
       APPENDIX  
       [0003]     Not Applicable.  
       BACKGROUND OF THE INVENTION  
       [0004]     1. Field of the Invention  
         [0005]     This invention relates generally to coil winding machines and, more particularly, to a coil winding machine having an applicator head.  
         [0006]     2. Related Art  
         [0007]     Coil Winding Machines are known. For example, U.S. Pat. No. 3,823,590 to Lang discloses a coil winding machine. The coil winding machine disclosed by Lang forms helical coils by rotating wire around a non-rotating mandrel. The Lang machine includes a frame  20  and a cantilevered tubular beam  28  connected to the frame. A non-rotating mandrel  45  extends through the tubular beam. One or more spools  32  having wire are mounted on the tubular beam. A coil forming rotor  50  removes wire from the spools and wraps it around the mandrel, thereby forming a helical coil. Lang does not disclose an apparatus or a method for directly applying a coil wire perpendicular to a core wire (i.e., a mandrel). In the apparatus disclosed by Lang, wire is payed off over the end, or hub, of the spool. Removing wire from the spool in such a manner greatly increases the probability that the finished helical coil will have a discontinuity.  
         [0008]     Additionally, it is known that some materials are more likely to produce a discontinuity in a finished helical coil. For example, some materials, such as stainless steel, have a significant shape memory. In other words, the material attempts to resume its original shape when released. The shape memory causes the finished helical coil to have a discontinuity, such as a wave or a distortion.  
         [0009]     There has been a general interest in these materials which have desirable formed helical coil properties and, coincidentally, also have significant shape memory. For example, it has long been desirable to produce helical coils of stainless steel. However, because stainless steel has a significant shape memory, there has been great difficulty in producing acceptable helical wound stainless steel coils. The difficulty arises as the stainless steel wire is unwound from a spool and formed into a helical coil the wire attempts to resume its original shape thereby causing a distortion in the finished product. Known methods of producing stainless steel coils result in coils having significant waves, or distortion, in the coil. Similar results are obtained with other materials, such as platinum.  
         [0010]     Thus, there remains a need in the art for a coil winding machine capable of producing distortion free helical coils.  
       SUMMARY OF THE INVENTION  
       [0011]     It is in view of the above problems that the present invention was developed. The invention is a coil winding machine for producing distortion free helical coils. The coil winding machine includes, among other things, one or more wire spools which are arranged in such a way that wire is payed off the spool perpendicular to a core wire. It has been found that paying off the wire from the spool in the same direction as it was put on, meaning tangentially and perpendicular to a spool axis, greatly decreases the probability that the finished coil will have a discontinuity. The perpendicular payoff is one aspect that allows for a distortion free coil.  
         [0012]     In another aspect of the invention, there is provided an applicator head. The applicator head assists in guiding the wire as it is wrapped around the core wire. The applicator head is proximate to a spindle nose. As core wire exits the spindle nose, the applicator head assists in wrapping the wire around the core wire to produce a distortion free coil.  
         [0013]     In another aspect of the invention, there is provided a back feed mechanism. The back feed mechanism allows for fine adjustment of the helical pitch. The back feed mechanism includes a sensor that measures wire pressure on the spindle nose. The sensor sends a signal to a controller that either speeds up the core wire travel speed or slows down the wrapping speed in order to maintain a specified pitch.  
         [0014]     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  
       [0015]     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:  
         [0016]      FIG. 1  is a front view of a coil winding machine;  
         [0017]      FIG. 2  is a top view of a coil winding machine;  
         [0018]      FIG. 3  is a detailed side view of a flywheel;  
         [0019]      FIG. 4  is a partial sectional front view illustrating a spindle nose and applicator head;  
         [0020]      FIG. 5  is a sectional side view of the applicator head; and  
         [0021]      FIG. 6  is a detailed front view of a spindle head assembly.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     Referring to the accompanying drawings in which like reference numbers indicate like elements,  FIGS. 1 and 2  illustrate a coil winding machine  10 . The coil winding machine  10  includes a core wire feed assembly  50 , a spindle head assembly  16 , a pull roll assembly  18 , and a cutter  22 . The coil winding machine  10  is used to produce coiled wire. In some embodiments, the coil winding machine  10  includes a base  70 , a touch screen monitor  72 , and a controller  74 .  
         [0023]     The core wire feed assembly  50  includes a wire payoff  52  and, optionally, a wire straightener  56 . A core wire spool  54  is rotatably connected to the wire payoff  52 . The wire payoff  52  can accommodate core wire spools of various sizes. The wire payoff  52  includes a braking mechanism (not shown) to control the rotational speed of the core wire spool  54 . The core wire spool  54  holds a core wire  100 , which is used as a continuous mandrel. The phrase “core wire” is meant to include any item that may be used as a substantially continuous mandrel. Core wire  100  may be comprised of plastic or metal material. In the depicted embodiment, the core wire  100  is a metal wire having a diameter up to 0.250 inches (6.35 mm). However, shapes other than wire, such as a tube or a conduit, maybe used as a core wire. The wire straightener  56  is an item used to remove twists in the core wire  100 .  
         [0024]     The spindle head assembly  16  is used to rotate a flywheel  24 . In the depicted embodiment, there is one flywheel. However, those skilled in the art will understand that multiple flywheels may be attached to the spindle head assembly  16 . The flywheel  24  may rotate in a clockwise or counter-clockwise direction. The flywheel  24  holds wire spools  26  (best seen in  FIG. 3 ). The spindle head assembly  16  rotates the flywheel  24  and the wire spools about the coil wire  100 . A spindle nose assembly  30  (best seen in  FIGS. 3 and 4 ) is operatively connected to the spindle head assembly  16 . The spindle nose assembly  30  does not rotate.  
         [0025]     The pull roll assembly  18  pulls the coil wire  100 . The pull roll assembly  18  has a plurality of drive wheels  12  and a plurality of driven wheels  14 . The drive wheels  12  are made of, or coated with, a frictional material to grip the driven wheels  14 . For example, the drive wheels  12  may be made of urethane and the driven wheels  14  may be made of steel. In the embodiments having a tube or conduit core wire, the wheels  12 ,  14  are grooved. In the depicted embodiment, there are three sets of wheels. However, a greater or lesser number of wheels may be used. Three sets of wheels have been found to evenly distribute the load upon the core wire  100 . The last set of wheels  13  may provide more than one function. As an example, the last set of wheels  13  not only pulls on the core wire  100 , but also prevents the formed coil wire from unwinding before it is cut.  
         [0026]     The pull roll assembly  18  is operatively connected to a power unit for rotating the drive wheels  12 . For example, the drive wheels  12  are rotatably connected to a servo motor  66  and a transmission  68 . In the depicted embodiment, the servo motor  66  is electrically connected to the controller  74 .  
         [0027]     In the depicted embodiment, the pull roll assembly  18  is pneumatically operated between an “up” position and a “down” position. For example, the pull roll assembly  18  may include a combination air cylinder and pressure regulator  19 . However, the pull roll assembly  18  could also be mechanically or hydraulically operated. The pressure regulator regulates the amount of clamping force on the core wire  100 .  
         [0028]      FIG. 3  illustrates a side view of the flywheel  24 . As noted above, wire spools  26  are mounted on the flywheel  24 . Each wire spool  26  holds wire  200 . As examples, the wire  200  may be a platinum wire or it may be a stainless steel wire. In the depicted embodiment, there are four wire spools  26 ; however, a greater or lesser number of wire spools may be used. Additionally, first wire guides  28  are also mounted on the flywheel  24 . While in the depicted embodiment there are four first wire guides  28 , a greater or lesser number of wire guides may be used. In some embodiments, there is also provided a second wire guide  29 . The second wire guide  29  is arcuate and is placed adjacent to one of the spools  26 . While in the depicted embodiment only one second wire guide  29  is shown, those skilled in the art will understand that a greater number of second wire guides may be used. For this last embodiment, the wire  200  would extend over the second wire guide  29  instead of the spool  26  as is depicted in  FIG. 3 .  
         [0029]     As best seen in  FIG. 6 , the wire spool  26  includes a tensioning collar  27 . Additionally, felts pads  25  are located on either side of the wire spool  26 . The tensioning collar  27  presses against the wire spool  26  and the felt pads  25 . The tensioning collar  27  is adjusted such that the wire spool  26  has a drag. The wire  200  is payed off the wire spool  26  at a controlled rate because of the drag.  
         [0030]     Referring once again to  FIG. 3 , an applicator head  32  is attached to the flywheel  24 . Wire  200  travels from the wire spools  26 , across the wire guides  28 , and through the applicator head  28 . Thereafter, wire  200  is wrapped around the core wire  100  to produce a formed coiled wire. The wire spools  26  and the applicator head  32  are arranged in such a way that the coil wire  200  is payed off perpendicular to the core wire  100 . This eliminates or substantially reduces waves or distortion in the finished coil wire. The flywheel  24  also includes a counterweight  33  opposite the applicator head  32 . The counterweight  33  counterbalances the mass of the applicator head  32 .  
         [0031]      FIG. 4  illustrates a spindle nose  31  and the applicator head  32 . The applicator head  32  is forward of the spindle nose  31 . The applicator head  32  includes guide pins  34 . The guide pins  34  guide the wire  200  through the applicator head  32 . A hinged cover  38  covers the wire  200  as it goes through the applicator head  32 . The applicator head  32  includes a spacer  37 . The spacer  37  guides the wire  200 . In the depicted embodiment, the spacer  37  is made from plastic shim stock and is 0.002 inches (0.05 mm) thicker than the wire  200 .  
         [0032]      FIG. 5  illustrates the applicator head  32 . The applicator head  32  includes a pressure adjustment plate  40 , a pressure adjustment screw  44 , a locknut  45 , and pressure pads  42 . The pressure adjustment screw  44  is used to adjust the tension in the wire  200  as it is wrapped around the core wire  100 . In the depicted embodiment, the pressure adjustment plate  40  is a resilient steel plate and the pressure pads  42  are made of felt. The pressure pads  42  encapsulate the wire  200 . The applicator head  32  includes inserts  36  and the spacer  37 . The applicator head  32  includes an arm  39 . The arm  39  places the inserts  36  and the spacer  37  proximate to the spindle nose  31 . The spacer  37  is located between the inserts  36 . The combination of the inserts  36  and the spacer  37  encapsulate and guide the wire  200 . In the depicted embodiment, the inserts  36  are made of carbide but other materials, such as tool steel, may be used. What is important is that the inserts have good wear characteristics without features that would scratch the wire  200 .  
         [0033]      FIG. 6  illustrates the spindle head assembly  16 . The spindle head assembly  16  has a spindle input  58 . The spindle input is operatively connected to a spindle (not shown) which is encased within a spindle head  46 . In the depicted embodiment, the spindle input  58  is a pulley but other devices, a gear for example, may be used. The spindle input  58  is operatively connected to a power unit (not shown), such as a servo motor. In the embodiment depicted in  FIG. 2 , the spindle head assembly  16  includes a rotational sensor  47  for counting the revolutions of the flywheel  24 . The rotational sensor  47  is connected to the controller  74 . The spindle input  58  is rotated by the power unit which in turn causes the flywheel  24  to rotate. The flywheel  24  rotates about the spindle nose assembly  30 . The spindle nose assembly  30  itself does not rotate. Core wire travels  100  through the spindle nose assembly  30 . Wire  200  is wrapped around the core wire  100  at the spindle nose  31 . One can control the pitch of the formed coil wire by adjusting the speeds of the core wire travel speed and the wrapping (flywheel) speed in relation to one another. For example, the controller  74  may be preprogrammed or manually programmed to vary the pitch of the formed coil wire. In this example, the controller  74  is manually programmed through the use of the touch screen  72 .  
         [0034]     In some embodiments it may be desirable to have a fine adjustment of the core wire speed to accurately maintain a specified pitch. In this case, some mechanism is required to physically measure the difference between the core wire speed in relation to the wrapping speed. Here, there is provided a back feed mechanism  60 . The back feed mechanism includes a sensor  62  and a sensing plate  64 .  
         [0035]     For embodiments having the back feed mechanism  60 , the spindle nose assembly  30  is movable fore and aft. In the depicted embodiment, the spindle nose assembly  30  is moved axially via a force air cylinder  80 . In contrast, in the embodiments having an applicator head  32 , the spindle nose assembly  30  is fixed axially. The applicator head  32  is not used in conjunction with the back feed mechanism  60 . A position adjusting air cylinder  82  is used to move the spindle from a first position for use in conjunction with the applicator head  32  to a second position for use in conjunction with the back feed mechanism  60 . The position adjusting air cylinder  82  may not be used in all embodiments, and those skilled in the art will understand that the spindle may be permanently locked in either the first or second positions.  
         [0036]     When the coil winding machine  10  is first started, spindle nose assembly  30  is in a neutral position. In the depicted embodiment, the sensor  62  has a 10 Volt range and the spindle nose assembly  30  is moved axially into a neutral position when the sensor output is 5 Volts. As the coil winding machine  10  operates, wire  200  is wrapped around the core wire  100 . If the wire  200  is wrapped around the core wire  100  faster than core wire travel speed can accommodate, then the wire  200  will have a tendency to press against a spindle nose collar  48 . This pressure against the spindle nose collar  48  causes the spindle nose assembly  30  to move rearwardly. This rearward movement cause the sensing plate  64  also to move rearwardly. Thus, the sensing plate  64  moves toward the sensor  62 . The sensor  62  sends a signal to the controller  74  which can speed up the core wire speed or slow down the wrapping speed. In this manner, a uniform wrap at a desired pitch can be achieved.  
         [0037]     In some embodiments, it is desirable to apply a UV-glue prior to cutting the formed coil wire. As best seen in  FIGS. 1 and 2 , a glue applicator  20  is provided to apply the UV-glue prior to cutting the formed coil wire. The glue prevents the formed coil wire from unraveling when it is cut. The glue applicator  20  applies and cures the glue to the formed coil wire. The glue applicator  20  is operatively connected to the pull roll assembly  18 .  
         [0038]     In a final step, the formed coil wire is cut by the cutter  22 . As examples, the cutter  22  may take the form of a shearing mechanism, a saw mechanism, or an abrasive cutter. By adjusting the frequency of the cutting action of the cutter  22 , one can adjust the length of the formed coil wire. In the depicted embodiment, the cutter  22  is operatively connected to the controller  74 . As an example, the controller  74  may be preprogrammed or manually programmed to vary the length of the formed coil wire.  
         [0039]     In operation, a core wire spool  54  having core wire  100  is placed on the wire payoff  52 . The core wire  100  is strung through the straightener  56 , the spindle, and the pull roll assembly  18 . The air cylinder  19  is engaged such that the core wire  100  is caught between the drive wheel  12  and the driven wheels  14 .  
         [0040]     Next, wire spools  26  having wire  200  are placed on the flywheel  24 . The wire  200  is strung through the first wire guides  28  and over the second wire guides  29 . The wire  200  is then strung over the pressure pad  42  and through the wire guide pins  34 . The wire  200  is then strung through the spacer  37 . Thereafter, the insert  36  is placed over the wire  200  and the hinged cover  38  is closed.  
         [0041]     Next, an operator may manually specify a desired pitch and length of the formed coil wire via the touch screen  72 . Alternatively, the desired pitch and length may be pre-programmed into the controller  74 . The desired pitch and length are stored in the controller  74 . The coil winding machine  10  is started and the wire  200  is wrapped around the core wire  100 . The completed wrap travels through the glue applicator  20  where UV glue is applied. Finally, cutter  22  cuts the formed coil wire to the desired length.  
         [0042]     To assemble the coil winding machine  10 , one first provides the base  70 . Next, the spindle head  46  is mounted on the base  70 . Next, the spindle nose assembly  30  is mounted to the spindle head  46 . Then, the flywheel  24  is rotatably mounted to the spindle head  46 . Next, one or more wire spools  26  is connected to the flywheel  24 . Then, one or more wire guides  28 ,  29  is connected to the flywheel  24 . Next, the applicator head  32  is connected to the flywheel  24 . Thereafter, the pull roll assembly  18  and the core wire feed assembly  50  are connected to the base  70 . The glue applicator  20  is connected to the pull roll assembly  18 . Next, the cutter  22  is connected to the base  70 . Then, the touch screen  72  and the controller  74  are connected to the base  70 . Finally, the controller  74  is electrically connected to the core wire feed assembly  50 , the spindle head assembly  16 , the pull roll assembly  18 , and the cutter  22 .  
         [0043]     In view of the foregoing, it will be seen that the several advantages of the invention are achieved and attained.  
         [0044]     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.  
         [0045]     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. For example, while four wire spools are shown in the depicted embodiments, a greater or lesser number of wire spools may be used. 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.