Patent Publication Number: US-2004040451-A1

Title: Wire coil winding apparatus and method

Description:
[0001] This Invention is a Divisional of patent application Ser. No. 10/234,752, filed Sep. 4, 2002. 
    
    
     
       FIELD OF THE INVENTION  
       [0002] The present invention relates to the field of wire coil winding and more particularly to apparatus and method for winding a wire coil and automatically banding the wound coil.  
       BACKGROUND OF THE INVENTION  
       [0003] Wire is generally supplied in one of three types of package, cut straight lengths in a box, wound on a spool or reel, and wound into a coil without any supporting spool. The present invention involves winding wire into a coil without any spool. Most wire, although somewhat susceptible to retaining a shape into which it is bent, will also exhibit a degree of resiliency and tend to partly return to its pre-bend shape. Therefore, a wire that has been wound into a coil shape will naturally tend to partly straighten, or expand diameterally. In addition, wire is normally wound in coils by the technique known as parallel winding, rather than cross winding. Parallel winding has no significant transverse vector to prevent the wound coil from spreading axially and losing its shape integrity.  
       [0004] Both the diameteral expansion and the axial spread have been historically controlled with banding that was applied by an operator manually placing a wire or tape through the center and around the periphery of the coil. If the banding material is a wire, the operator performing the banding operation twisted the ends together, trimmed the excess banding and flattened the twisted wire against the coil periphery. If the banding material is tape, coil security may require multiple wraps for each position. Since a typical wire coil needs three or four circumferentially separated bands for secure support, this manual operation involves a significant amount of time and effort. The time involved both prevents the machine devoted to coil winding from further production during the banding operation and increases the labor cost of making the wire coil.  
       [0005] Therefore, it is an object of the present invention to provide a wire coiling apparatus and method capable of automatically banding a wound coil.  
       [0006] It is an additional object of the present invention to provide a wire coiling apparatus and method capable of automatically banding a wound coil with a wire band and causing the twisted ends of banding wire to be flattened against the coil.  
       [0007] These and other objects will become more apparent from the description of the invention to follow.  
       SUMMARY OF THE INVENTION  
       [0008] A wire coil winding machine is provided with an automatic coil banding mechanism. The wire is wound on a mandrel between a pair of flanges to form a coil. The mandrel and flanges as a unit have a number of channels cut into their mutual inner surface. At the completion of winding a selected quantity of wire, the winding stops. A series of bands are automatically driven through a channel so as to encircle the coil from its bore to its circumference. The ends of the bands are secured around the coil. The completed coil is ejected from the mandrel and a second coil is started. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0009]FIG. 1 is a schematic elevation view of the coil winding apparatus of the present invention.  
     [0010] FIGS.  2 A- 2 D are a series of detailed sequential operational diagrams of a coil banding section of the apparatus of the present invention.  
     [0011]FIG. 3 is an enlarged cross sectional view of the coil winding mandrel and flanges as taken in the direction of line  3 - 3  of FIG. 2A with a completed wire coil mounted thereon.  
     [0012]FIG. 4 is an enlarged perspective view of a wound and banded wire coil as formed according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] According to the illustration of FIG. 1, the present invention provides a machine  10  for winding a wire supplied in long continuous lengths into compact, uniform coils. Although the preferred embodiment of the invention is depicted in terms of winding a wire product, i.e. an elongate metallic member, it is recognized that the principles of the present invention can be applied to other bendable materials, such as monofilament plastic materials. A loosely formed wire supply bundle  14 , formed of a long length of wire  18 , is mounted onto a wire supply holder  12  at the entry end of coiling machine  10 . For satisfactory operation, wire supply bundle  14  must be formed with the wire in substantially parallel, not tangled, loops. The present invention also contemplates winding wire from a supply spool to a coil. The possible supply spool may optionally be allowed to revolve around a shaft with an applied drag or remain still while the wire is pulled off axially, perhaps with the aid of a flyer, as is known. The wire  18  is threaded from supply holder  12  through a guide  20  that is situated over the approximate center of supply holder  12 , and then past a break-out sensor  22  to be wrapped partly around pulley  24 . Wire  18  is held in intimate contact with the surface of pulley  24  by a captured belt (not shown) which is in contact with a portion of the circumference of pulley  24 . Wire  18  travels in the direction indicated by several arrows along its length. Sensor  22  may be any sort of known sensing device to confirm the presence of wire  18  adjacent thereto, or, if no wire  18  is detected, to stop operation of apparatus  10  or signal an operator that a problem exists. The entry edge of pulley  24  is vertically aligned with guide  20  and sensor  22 . Pulley  24  is rotatably mounted on a shaft and is able to create an adjustable amount of running tension in wire  18  by the application of a controllable drag, for example as created by a magnetic brake  26 . Alternate means for creating tension, for example a mechanical brake, would also perform the basic function required. However, the use of magnetic brake  26  permits adjustment and control of its applied drag with electrical signal input from a microprocessor such as PLC  68 , according to the preferred embodiment of the invention.  
     [0014] Wire  18  is then threaded in an elongated loop around a dancer assembly including rotatably mounted sheave  30  and dancer sheave  32  to pass through guide  38  and wound partly around drive capstan  40 . Sheave  30  and dancer sheave  32  each represent multiple sheaves on a pair of common shafts, in the preferred embodiment. Sheave  30  is mounted fixedly in a position so its top edge is preferably in tangential contact with a horizontal line extending from the top of tension pulley  24  to the center of guide  38 . Dancer sheave  32  is mounted so as to be able to move, e.g. upwardly, in response to increased tension on wire  18  in the direction indicated by arrow A. When wire  18  is running without tangles in the range of normally applied supply tension, dancer sheave  32  is in its normal state being held at or close to the bottom of its travel distance by an applied force, in the preferred embodiment being caused by a pneumatic cylinder (not shown). A detector  34  is positioned adjacent dancer  32  to provide a warning signal or to shut down machine  10  in case of a great increase in operating tension on wire  18 . For example if supply bundle  14  becomes tangled or wire  18  is snagged, dancer sheave  32  will be raised, due to the tension on wire  18 , to the position shown in dashed lines  32   a , and detector  34  will be actuated.  
     [0015] Continuing with reference to FIG. 1, after passing through guide  38 , wire  18  is wrapped partly around drive capstan  40  which is driven by a motor (not shown). Wire  18  is held in intimate contact with drive capstan  40  by means of a captured belt (not shown) which conforms to drive capstan  40  around approximately one quarter of its circumference. Alternately, wire  18  may be wrapped multiple times around drive capstan  40  for secure drive speed control. Capstan  40  operates at a substantially constant rotational speed to impart the force to drive wire  18  at a substantially constant linear speed. A guide tube  42  is mounted along a line that is vertically tangent to the exit edge of drive capstan  40  and perpendicularly centered on an upper surface of cutter  46 . Guide tube  42 , in the preferred embodiment, is formed with two partial tubes that are telescopically extendable in the direction indicated by arrow B. The upper portion of guide tube  42  is vertically positionable as shown by arrow B to be close to capstan  40  during operation of apparatus  10  and farther from capstan  40  for ease of threading wire  18  therethrough. A device, e.g. a locking collar (not shown), is provided to affix guide tube  42  at a selected length. The lower end of guide tube  42  is fixedly mounted an arbitrary distance above cutter  46 .  
     [0016] Cutter  46  is formed, in the preferred embodiment, by an upper and a lower guide plate, each having a vertical through hole formed therein. Each through hole is aligned with the other through hole during winding of a wire coil in machine  10  to allow wire  18  to pass freely. Alternate cutter designs may be employed within the scope of the present invention. Wire  18  is moved by capstan  40  to pass through telescoping guide tube  42  and through the aligned upper and lower holes in cutter  46 . The forward end of wire  18  ultimately moves to a winding station to pass in contact with guide pulley  48  that is positioned beneath and aligned with the guide holes in cutter  46 . In the preferred embodiment, the leading end of wire  18  is fed past guide pulley  48  and into a hole or slot in mandrel  72  at the beginning of a winding cycle. Coil winding proceeds at a relatively slow rotational speed for several revolutions, e.g. four revolutions, until wire  18  is securely engaged on mandrel  72 , and then gradually accelerates to a pre-selected constant linear running speed which is maintained for the balance of the wind cycle. The running speed of wire  18  is preferably a substantially fixed linear speed as controlled by drive capstan  40 . The rotation of coil  50  is driven at decreasing rotational speed by a motor (not shown) that is operating in what has been known as torque mode so as to match the fixed linear speed of and provide drawing tension to wire  18 .  
     [0017] Guide pulley  48  is maintained in a fixed position to control wire  18  as it is wound into a coil  50  as described more fully below. During the winding cycle in which coil  50  is formed, coil  50  is rotated in the direction indicated by arrow C, and coil  50  is simultaneously moved axially in a direction into and out of the plane of FIG. 1 to create a slow traverse parallel-wound coil. “Parallel wound” is a term used to indicate that each loop of wire  18  in coil  50  is substantially perpendicular to the axis of coil  50  and substantially parallel to other wire loops in a wire layer. The pitch of winding from a first to a subsequent adjacent wire loop on the circumference of coil  50  is adjustable by changing the speed at which coil  50  is caused to traverse (into and out of the plane of FIG. 1) while the linear speed of wire  18  remains constant so as to optimize productivity. The traverse movement of coil  50  is driven by a separate drive motor connected to a linear actuator, for example a drive screw mechanism.  
     [0018] Coil  50  is wound in the winding station on a mandrel  72  between two spaced apart flanges as will be described more fully below. Mandrel  72  is rotated by a motor capable of variable speed operation and having an encoder to signal the number of revolutions run and its angular position. Coil  50  winding continues to rotate until a pre-set value, representing a selected length of wire  18 , has been reached. A finished coil  50  is preferably similar in outer diameter to the diameter of flanges  70   a  and  70   b . At the completion of the winding cycle, wire  18  and mandrel  72  gradually decelerate and simultaneously stop operating. A banding supply station  54  supplies plural lengths of banding material  56 , preferably a banding wire, to place multiple bands perpendicularly from the bore to the periphery of coil  50 . After the application of one or more bands, one of the guide plates of cutter  46  is caused to move, e.g. by a pneumatic cylinder, in a direction perpendicular to the linear direction of wire  18  to sever wire  18  in a scissor-like action between the upper and lower guide holes. The plates of cutter  46  are returned to their normal position in which the guide holes are aligned. Coil  50  is caused to rotate slowly for a portion of a revolution in a direction opposite to that indicated by arrow C to cause the cut end of wire  18  to engage bar  52  and be turned backwards as compared to the direction in which coil  50  was wound. In this manner, wire  18  is secured against unraveling by being locked around a band of banding wire  56 . Mandrel  72  and coil  50  are indexed  900  to apply each successive band in the manner described above until a selected number, e.g. four, bands are applied.  
     [0019] FIGS.  2 A- 2 D illustrate sequential operational steps of positioning coil  50  for banding, passing a banding material through the bore of coil  50 , bringing the ends of the banding material together, and twisting the ends of banding material together. As illustrated in sequential FIGS.  2 A- 2 D, coil  50  is banded by wire banding material  56 , supplied by banding supply station  54  and banding driver and cutter mechanism  58 . FIG. 2A is a vertical plan view of the winding mandrel  72 /flange  70   a  combination and separable flange  70   b  with a coil  50  formed therebetween at the end of the winding cycle. Banding material  56  is moved from banding supply station  54  toward coil  50 . Depending on the characteristics of banding wire  56 , banding driver and cutter mechanism  58  is optionally equipped with a wire straightening unit, as is known. Wire banding material  56 , for purposes of banding, is preferably relatively annealed, as opposed to being hard and resilient, so as to be compliant when twisted.  
     [0020] In FIG. 2A, flange  70   a  is seen to have a series of channels  76  that are separated circumferentially at angles of 90° from one another. As seen in FIGS. 2 and 3, channel  76  is wider at the periphery of flange  70   a  than it is in the portion cut into mandrel  72  and in the continued narrow channel passing outwardly radially along flange  70   b . Channels  76  are open toward the inner surfaces of flanges  70   a ,  70   b  and mandrel  72 . The mouth of channel  76   a  is relatively wide both in the circumferential and the axial direction of flange  70   a . Flange  70   b  is separable from mandrel  72  (see FIG. 3) by being moved in the direction indicated by arrow H.  
     [0021] Returning to FIG. 2A, banding wire  56  is moved from supply station  54  toward flange  70   a . Banding wire  56  is cut to a desired length by a cutting mechanism  58  as is known in the trade. An alternate possibility is to supply precut lengths of banding wire  56 . In FIG. 2B, banding wire  56  passes through flange  70   a  and through channel  76  to exit from flange  70   b . A pair of forks  74   a  and  74   b , each formed with a “V” shaped open end that are oriented to face one another, are then caused to move toward each other in the direction indicated by arrows F to press the ends of banding wire  56  toward each other, forming a loop around one portion of coil  50 . Once the ends of banding wire  56  are brought together, shown in FIG. 2C, jaws  62   a  and  62   b  are pivoted toward each other in the direction of arrows E, to clamp onto the ends of banding wire  56 , and forks  74   a  and  74   b  are separated in the direction of arrows F to rest in the positions shown in FIG. 2D. In FIG. 2D, jaws  62   a  and  62   b  are shown as being caused to rotate in the direction shown by arrows G while maintaining pressure to grip the ends of banding wire  56  so as to twist the ends of banding wire  56  together. Jaws  62   a  and  62   b  may optionally be rotated either clockwise or counterclockwise. After a predetermined number of twists have been imparted to the ends of banding wire  56 , e.g. 8-12 turns, jaws  62   a  and  62   b  separate. Jaws  62   a  and  62   b  are formed with a pressure contact area (not shown), and the number of turns applied by jaws  62   a ,  62   b  is determined to be sufficient to securely bind coil  50  and cause the portion of banding wire  56  distal from coil  50  to break off. Jaws  62   a  and  62   b  open, and coil  50  is rotated  900  to position another set of channels for the insertion and securing of banding wire  56 .  
     [0022] The forming of wire bands as described above results in a twisted wire end protruding radially outwardly from coil  50  at each band position, i.e. four locations. In order to flatten the twisted wire ends against the peripheral surface of coil  50 , bar  52  (see FIG. 1) is located close to the circumference of finished coil  50 . Coil  50  rotates between sequential banding operations, causing the twisted ends of banding wire  56  to be bent toward the circumferential surface of coil  50 . Lastly, ram  66  is advanced rapidly in the direction of arrow D to impact the twisted ends. Ram  66  is shaped substantially to match the contour of the periphery of coil  50 . This flattening operation is repeated for each of the plural banding wires. Ram  66  is actuated by a pneumatic cylinder or other driver.  
     [0023]FIG. 3 provides an enlarged, detailed cross sectional view of flange  70   a  mandrel  72  and flange  70   b  with completed coil  50  in position therebetween. Flanges  70   a  and  70   b  surround coil  50 , and banding wire  56  (shown as a dashed line) passing through channel  76   a  proceeds across the mandrel portion to exit through flange  70   b . At the completion of winding and banding coil  50 , flange  70   b  separates from the fixed assembly of flange  70   a  and mandrel  72 , and an ejector (not shown) discharges coil  50  from mandrel  72  onto a receiving conveyor or into a container.  
     [0024]FIG. 4 illustrates coil  50  in completed wound and banded form with four bands  56  individually wrapped through the bore and around the periphery of coil  50 . A typical set of dimensions for completed coil  50  is that bore diameter d equals about 4.1 cm (1.625 inch), outer diameter D equals about 13.6 cm (5.375 inch), and traverse width W equals about 4.6 cm (1.812 inch). Coil size is dependent upon the ultimate use to which coil  50  is put.  
     [0025] Coiling machine  10  (FIG. 1) is operationally controlled by microprocessor  68  connected thereto. Microprocessor  68  is capable of installing a previously recorded program or accepting operator-set parameters to automatically control the coil winding process of machine  10 . Each parameter is represented by a counter and display on a screen (depicted as circles on the screen of microprocessor  68 ), with controls set to selected values by use of a touch screen or a keyboard. Relevant parameters, according to the preferred embodiment, include wire linear speed, mandrel traverse speed, wire diameter, number of mandrel  72  turns at slow speed before accelerating to running speed, magnetic brake  26  force to instill tension, mandrel  72  drive torque, total length of wire  18  on coil  50  before stopping winding, length of banding wire  56 , number of banding wire  56  twists and number of ram  66  impacts per wire banding. Microprocessor  68  receives signals from sensor  22  as to the presence of wire  18  and from detector  34  as to the position of dancer  32  and of potentially excessive tension in wire  18 , as well as operational information such as the linear running speed and quantity wound of wire  18  and the number of coils  50  completed in the production lot. Microprocessor  68  is adapted to save the operating parameters for a complete program in an internal memory or to record to a disc for future use. Alternately, the parameters comprising the operating program may be saved to a tape or disc memory device.  
     [0026] Therefore, the sequence of operations for automatic coil winding according to the preferred embodiment of the invention is as follows, referring to FIG. 1 for reference. An operator places a wire supply package  14  on wire supply holder and threads the wire  18  through guide  20 , past wire presence sensor  22  and around pulley  24  with magnetic brake  26 . Wire  18  is further threaded around sheave  30  and dancer sheave  32  which is monitored by detector  34  to signal the operator and/or shut down operations in the event of excessive tension. Wire  18  next passes through guide  38  and around drive capstan  40 , through telescopic tube  42 , through cutter plates  46  and around pulley  48  to mandrel  72 . The operator either manually enters values for winding control on microprocessor  68  or inputs a pre-recorded control program. Wire  18  is fed into a slot in mandrel  72 , and mandrel  72  slowly rotates as it slowly traverses axially. At the completion of several rotations at slow speed, mandrel  72  begins to rotate faster as the traverse similarly moves axially faster to maintain a constant ratio of mandrel revolutions to traverse motion. Mandrel  72  operates during the beginning of the winding cycle at a full rotational speed that decreases as the diameter of coil  50  increases so as to keep the linear speed of wire  18  constant. When the length of wire  18  on coil  50  approaches its pre-set maximum quantity, mandrel  72  begins to slow and then stops at the pre-set quantity. Mandrel  72  is rotated to a position where a first one of several channels  76  is positioned in line with banding wire  56  coming from banding wire supply  54 . A length of banding wire  56  is moved to pass through channel  76  from a first to a second flange adjacent mandrel  72 , through the bore of coil  50 . The two ends of banding wire  56  are brought together by a pair of forks  74   a ,  74   b  (see FIGS.  2 A- 2 D) and grasped by jaws  62   a ,  62   b  as forks  74   a ,  74   b  retract. Jaws  62   a ,  62   b  rotate to twist the ends of the banding wire together and clip the excess length therefrom. Jaws  62   a ,  62   b  open, and mandrel  72  rotates to the next sequential banding position, for example 90° farther, where the banding process is repeated. Cutter  46  cuts wire  18  between application of banding wires, and the cut end of wire  18  is turned back on itself and flattened by contact with bar  52  as mandrel  72  is rotated backwards for this purpose. In rotating to a next banding position, mandrel  72  causes each twisted wire end to pass under bar  52  to bend the twisted ends close to the periphery of coil  50 . When a set of twisted ends is positioned appropriately, ram  66  is driven forward to flatten the twisted ends into a relatively safe placement against coil  50 . After all banding is completed and the twisted ends are flattened into the surface of coil  50 , flange  70   b  moves away from mandrel  72  and a discharge ram is actuated to eject completed coil  50 . Upon a signal from a sensor that coil  50  has moved out of the winding mechanism, flange  70   b , moves back into contact with mandrel  72  and the process is repeated.  
     [0027] While the present invention is described with respect to specific embodiments thereof, it is recognized that various modifications and variations may be made without departing from the scope and spirit of the invention, which is more clearly and precisely defined by reference to the claims appended hereto.