Start wire positioning method and apparatus

Abstract: A wire positioning mechanism and method for positioning a start wire (84) of a coil bundle from the bottom of the coil bundle to the top of the coil bundle during winding of the coil (100). The mechanism includes a pivotable and retractable arm (44) with a clamp assembly (80, 82), a contacting finger (60), and a wire hook (66) on one end thereof. The start wire (84) is first deflected into the space (96) between the two separated sections (92, 94) of a coil form (91) by the contacting finger (60). The wire (84) is then lightly clamped. The coil is then wound on the coil form (91) so that the start wire (84) will be positioned inside the coil (100). The wire hook (66) is then activated to reposition the start wire (84) through the coil bundle (100) and out over the top of the coil bundle (100). The start wire positioning mechanism (30) is then moved out of the way of the coil (100) and the winding operation is completed.

Description: This invention relates to an apparatus for winding a coil and a method for positioning of a coil start wire of a wound coil prior to the insertion of the coil into the stator core of a dynamoelectric machine. Conventionally, the stators of electric motors are manufactured by first providing a slotted core formed of a stack of laminations. Windings or coils are then wound and are subsequently inserted into the slots of the stator core. Quite often more than one set of windings is provided for an electric motor such as for instance a main winding and an auxiliary winding. The auxiliary winding is generally the last winding to be inserted into the stator core. Conventionally, the start wire of the auxiliary winding is located on the bottom of the coil bundle prior to the insertion of the winding into the core slots. Thus, after insertion, the start wire is located closest to the bore side of the stator core. This is not a very desirable location for the start or lead wire as in that position the start wire is quite vulnerable to damage from both the sharp edges of the laminations as well as from subsequent pressing and compressing operations in the windings. Thus it is desired to provide a method and apparatus for relocating or repositioning the start wire, after winding of a coil but prior to insertion of the coil into the stator core. In the prior art such repositioning has been accomplished manually by an operator who manually manipulated the wire from the bottom of the coil bundle to the top of the coil bundle. After insertion into the stator the start wire would then be located between the auxiliary coil and the main coil. Since this is a low density portion of the wire pack, the start wire would then be protected in the subsequent pressing and compressing operations. The disadvantage of the prior art manual method of repositioning the start wire has been that the process is cumbersome, time consuming and therefore costly. FR-A-21 20 897 discloses an apparatus for winding a coil according to the preambel of claim 1. The purpose of the prior art apparatus is to avoid an awkward interpole connection arrangement wherein the interpol connection had to extend from the smallest coil around the outside of the boundle of coils on one side all the way to the largest coil on the other side. The arrangement of the prior art apparatus shows that the winding is preferably started with the smallest coil on one hand side and extends to the largest coil on the other hand side boundle of coils so that the interpole connection segment is much shorter than in the prior art discussed in FR-A-21 20 897. During the winding process the progressively larger coils are sequentially wound over the starting end of the coil. That is to say the starting wire is not moved after winding of the coil through the middle of the coil bundle to stick out over its top. The start wire does extend through the coil boundle on one side. However the apparatus according to FR-A-21 20 897 does not provide any mechanism for moving the start wire automatically. It is therefore desired to provide a method and apparatus for automatically repositioning the start wire of a coil while the coil is being wound, so that, upon subsequent insertion of the coil into a stator core, the start wire is located in a protected location. In accordance with the invention, this object is accomplished in an apparatus according to claim 1 and a method according to claim 8. The present invention overcomes the disadvantages of the above described prior art manual start wire repositioning method by providing an automatic method and an apparatus therefor. The method according to the present invention comprises positively positioning the start wire during winding of the coil and clamping it in that position while the coil is being wound. After the coil has been wound the start wire is then repositioned to the top of the coil, the coil is stripped from the winding tools and is then inserted into a stator core. More specifically, the method according to the present invention comprises positioning the start wire along one side of the segmented coil form whereby a portion of the start wire spans the space between the two sections of the segmented coil form. A start wire positioner is then moved into contact with the start wire and then deflects a portion of the start wire inwardly into the space between the coil form sections. The start wire is then clamped in that deflected position by a clamp. The coil is then wound on the coil form. Thus, at this time, the start wire is positively positioned inside the coil. After the coil is wound, the start wire is released from the clamp and a wire hook is rotated to reposition the free start wire end through the coil and out of the top of the coil. The wire hook is then retracted and the coil is stripped from the coil form for subsequent insertion into a stator core. An advantage of the present invention is that the start wire of a coil is automatically repositioned into a position wherein damage to the start wire is prevented during insertion of the coil into a stator and during subsequent pressing and finishing operations of the stator coil. Since start wire positioning is accomplished as part of the coil winding process, the operation is very efficient and takes up very little time of the manufacturing process. Accordingly, the method and apparatus according to the present invention prevents damage to the start wire of a coil in a very efficient and economic manner. It is another advantage of the present invention to provide a start wire positioning mechanism and method for a coil winding machine which prevents damage to the start wire during the insertion and subsequent pressing operations of the stator coils of a dynamoelectric machine. A further advantage of the present invention is to provide a method and apparatus for positioning a start wire which are reliable and efficient. The above mentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein: Fig. 1 is a cross-sectional elevational view of the stator of an electric motor with two windings and with the start wire of the auxiliary winding positioned between the two windings; Fig. 2 is a front elevational view of the positioning apparatus according to the present invention; Fig. 3 is a top plan view of the positioning mechanism of Fig. 2; Fig. 4 is a partial enlarged view of the deflecting finger and clamp of the positioning mechanism of Fig. 2; Fig. 5 is a partial elevational view of the end of the wire hook of the positioning mechanism of Fig. 2; Fig. 6 is a top plan view of a coil as it is being wound and of the deflected position of the start wire inside the coil; Fig. 7 is an elevational view showing the relative position of the coil form and the rest position of the start wire positioning mechanism; Fig. 8 is an elevational view of the coil form and the start wire positioning mechanism after the mechanism has pivoted into the operating position; and Fig. 9 is an elevational view of the coil form and the wire positioning mechanism as the start wire is being positioned through the coil by the wire hook. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. The exemplifications set out herein illustrate a preferred embodiment of the invention, in one form thereof, and is not to be construed as limiting the scope of the disclosure or the scope of the invention in any manner. Referring to Fig. 1 there is shown a conventional stator core with a portion thereof broken away. The stator core is formed of laminations 12 and includes a bore 14. A main winding 16 and an auxiliary winding 18 are inserted into stator core slots 20 located inside bore 14. The start wire 22 of auxiliary winding 18 is shown located in a preferred position between the two windings 16 and 18. If the auxiliary winding 18 were wound on conventional winding equipment without any special positioning of the start wire and were then inserted into the stator core, the start wire would be located on the bottom of the coil bundle and, after insertion, on the inside or bore side of winding 18. In that position start wire 22 would be subject to damage as explained hereinabove. The method and apparatus of the present invention, as further described hereinbelow, repositions the start wire from the bottom or bore side of the coil bundle 18 to the inside or top side of the coil bundle 18, prior to insertion of coil 18 into the stator core. After repositioning the wire to the top of the coil bundle and conventional insertion the start wire will be located between the two coil bundles as indicated in Fig. 1. Referring now to Figs. 2 and 3, the start wire positioning mechanism 30 is shown. A base 32 is provided with a bracket 34 to support the positioning mechanism. A pivot plate 31 is pivotally connected to bracket 34 by means of shaft 36. A pair of guide members 40a and 40b are mounted to this pivot plate 31. A slide plate or arm 38 is slidably received in guides 40a and 40b. A cylinder 42 having an activating rod 44 is connected to a bracket 46 which in turn is connected to slide 38. Thus, cylinder 42 can cause slide 38 to move outwardly or inwardly in guides 40 which, as pictured in Fig. 2 and 3, is respectively from right to left and vice versa. A cylinder 48 is also provided including an activating rod 50 which in turn is connected to a rod eye 52. By activating cylinder 48, the slide assembly including slide 38, guides 40a, 40b, pivot plate 31, and activating rod 44 and bracket 46 may be made to pivot upwardly or downwardly on shaft 36. Thus, arm 38 together with bracket 46 may pivot about shaft 36 and may be extended or retracted outwardly and inwardly as viewed in Figs. 2 and 3. As best seen in Figs. 2-5, bracket 46 has secured to the end thereof a clamp assembly 62 and a contact or deflecting finger 60. Clamp assembly 62 includes a clamp cylinder 64 for activating the clamp. Slide 38 also has pivotably secured thereto a wire hook 66 which is rotated by means of a lever 68, a shaft 70 and a rotary actuator 72. A support rod 74 is also secured to guides 40a, 40b and slide plate 38 for purposes further explained hereinafter. A sliding support 76 is provided for rod 74. As best seen in Fig. 4, clamp assembly 62 includes a clamp body 80 and a pivoting clamp 82. A coil start wire 84 is shown clamped between clamp body 80 and clamp 82. Contact finger 60 forms an extension of clamp body 80. By actuation of cylinder 64, activating rod 88 can activate clamp 82 to clamp start wire 84 as shown in Fig. 4. When cylinder 64 is deactivated, spring 86 forces clamp 80 to open, thereby releasing start wire 84. As seen in Figs. 4 and 5, located immediately side by side and adjacent to clamp assembly 62 is the end portion of wire hook 66 including a slot 90. Thus, as shown in Fig. 4, as start wire 84 is clamped in clamp assembly 62, slot 90 is aligned to receive start wire 84 when wire hook 66 is rotated clockwise. The operation of the apparatus is illustrated in Figs. 6-9. Initially, at the start of the cycle, the start wire positioning mechanism 30 is in the downwardly pivoted, at rest position as shown in Fig. 7. In this position slide 38 is in its retracted position, and bracket 46 is pivoted downwardly, out of the way of the segmented coil form 91 of which one segment 92 is shown in Fig. 7. The coil form 91, as conventionally constructed, includes two or more segments or sections 92 and 94 which are separated by a space 96 as best seen in Fig. 6. These segments may be adjusted relative to each other for winding various sizes of coils. Conventionally, the coil form sections 92 and 94 are stepped as seen in Fig. 7 whereby a coil bundle may be formed having coil sections of various sizes for insertion into the various slots of a stator core. The winding dispenser or flyer 102 shown in Fig. 6 is at rest at this time with the end of the start wire clamped in a cut/clamp unit 98. The start wire positioner mechanism 30 is now pivoted to its upright or horizontal position. Slide 38 is still in its retracted position at this time. The clamp assembly 62 will be deactivated. The wire dispenser or flyer 102 is now rotated approximately 180° to place the first turn of wire on the right hand side on the lowest winding section of the winding form as shown in Fig. 6. Thus, the start wire 84 will bridge space 96 between coil form sections 92 and 94. Flyer 102 will then stop and slide 38 is extended so that finger 60 contacts start wire 84 and deflects start wire 84 inwardly into space 96 as seen in Fig. 8. A portion of start wire 84 as well as clamp assembly 62, finger 60 and the end of wire hook 66 will now be located between the coil form sections 92 and 94, out of the way of the exterior surfaces of coil form 91 on which coil 100 will be wound. Thus winding of the coil can proceed unimpeded by positioning mechanism 30 while start wire 84 is positively positioned inside coil form 91. The winding tools are lowered to the first winding position so that coil form 91 is ready to receive the first layer of coil windings. As coil form 91 and cut/clamp 98 are lowered, start wire 84 will be lowered into clamp assembly 62. Cylinder 66 can therefore be activated so that clamp 82 clamps start wire 84. Start wire 84 will only be clamped lightly by clamp assembly 62 so that start wire 84 can still move in clamp 82 as coil form 91 is lowered prior to winding additional coil layers on the stepped coil form. Further it should also be noted by reference to Fig. 4 that the start wire 84, in its clamped position, will be located just above the bottom of slot 90 of wire hook 66. By reference to Figs. 3 and 6 it can be seen that wire hook 66 is located parallel to and immediately next to clamp assembly 62. Thus, in the position of start wire 84 as shown in Fig. 4 wire hook will be in position to capture start wire 84 as wire hook 66 moves clockwise as further explained hereinafter. The winding cycle is now continued by the rotation of flyer 102 relative to coil form 91. A layer of coil is therefore wound on the lowest winding section or stepped portion of coil form 91. Coil form 91 is then stepped downwardly and another layer of wire is wound on the second stepped portion of coil form 91. Some time during this process the end of start wire 84 will be unclamped from cut/clamp unit 98. Winding of the coil continues on the stepped portions of coil form 91 until the coil is completed. At this time as best seen in Fig. 6, start wire 84 is still positively positioned inside coil form 91. Referring now to Fig. 9, wire hook 66 is rotated by the actuation of rotary actuator 72. The movement of wire hook 66 will capture start wire 84 in slot 90 and will move the free wire end through the inside of coil 100 and out over the top of the coil bundle. The wire hook 66 is now retracted and wire clamp 82 is opened by deactivation of cylinder 64. Start wire positioning mechanism 30 is now pivoted downwardly to move clamp assembly 62 and wire hook 66 out of the coil. Slide 38 is now retracted. As start wire positioning mechanism 30 is lowered, rod 74 will continue to support coil 100 until slide 38 is retracted sufficiently far. It should be noted from Fig. 3 that arm 74 is longer than slide 38 and therefore extends further to the left as seen in Fig. 3. Thus arm 74 will support coil 100 to prevent interference of the coil with clamp assembly 62 and the end of wire hook 66 as arm 38 is retracted. It should be noted that, while clamp 82 is opened only after start wire 84 has been repositioned through the coil bundle, clamp 82 could be opened prior to movement of wire hook 66 to capture start wire 84 and repositioning of start wire 84. Another manner of constructing the coil form would be to form a recess in the lowest winding section of coil form 91. The start wire 84 could be positioned in the recess while several layers of coil wire are then wound on this lowest winding section. Thus more turns of wire could be wound and stored on the winding section while the start wire could be deflected and repositioned in the same way as explained hereinabove. Another variation on the invention would be to initially position and store the start wire 84 outside of the coil form, out of the way of the winding head and layers of coil to be wound. After winding of the coil the start wire would then be repositioned through the coil identically as disclosed hereinabove. Still another variation on the invention would be to initially deflect and position the start wire 84, to then complete winding of the coil, and thereafter to thread the start wire 84 through the layers of coil wire rather than through the center of the coil to reposition the start wire from the bottom of the coil bundle to the top of the coil bundle. What has therefore been shown is a very effective and efficient mechanism and method for positioning a start wire and for moving the start wire from the bottom of a coil bundle to the top of the coil bundle as the coil is being wound.

Claims: An apparatus for winding a coil (100) for a dynamoelectric machine and for positioning the start wire (84) of the coil (100) from one end of said coil (100) to the other end of said coil (100), said apparatus comprising: a segmented coil form (91) having at least two segments (92, 94) including a space (96) separating two segments (92, 94) thereof; a cut/clamp unit (98) for securing the starting end of the start wire (84) of the coil (100); a wire dispenser (102) fed by a wire source for winding a coil (100) on said coil form (91) characterized by; a start wire positioning mechanism (30), having an extendable arm (38) including a deflecting finger (60) for deflecting inwardly into said space (96) the first portion of said start wire (84) positioned against said coil form (91) by said wire dispenser (102) and bridging said space (96) at the beginning of the winding cycle and including a movable wire hook (66) for capturing the free wire end of the start wire (84) after being unclamped from said cut/clamp unit (98) and for repositioning said start wire (84) of said coil (100) from one end of said coil (100) through said coil (100) and out of the other end of said coil (100) after the winding of the coil (100) is completed. The apparatus according to claim 1 wherein said start wire positioning mechanism (30) includes a clamp means (82) for clamping said start wire (84). The apparatus according to claim 1 wherein said wire hook (66) is of a circular shape and is rotatable through an angle in the range of 90° - 180°. The apparatus according to claim 1 wherein said positioning mechanism (30) is pivotally mounted for pivoting movement between operative and inoperative positions. The apparatus according to claim 1 wherein said arm (38) includes a clamp assembly (62) for clamping said start wire (84). The apparatus according to claim 5 wherein said wire hook (66) having a capturing means (90) positioned adjacent said clamp (62), whereby a start wire (84) clamped in said clamp (82) is positioned to enable said capturing means (90) to capture said start wire (84). The apparatus according to claim 5 wherein said clamp (82) is adapted to lightly clamp said start wire (84) and to permit movement of said start wire (84) in said clamp (82). In a coil winding apparatus, a method for positioning a coil start wire through a wound coil (100) at the end of the winding of the coil, the coil winding apparatus including a cut/clamp unit (98) and a wire dispenser (102) operatively associated with a segmented coil form (91) having a space (96) separating at least two of the coil segments (92, 94), and a start wire positioner (30) including a clamp (82), a deflecting finger (60), and a wire hook (66), said method characterized by: initiating winding a coil (100) by positioning a start wire (84) by said wire dispenser (102) along one side of the coil form (91) with a portion of the start wire bridging the space (96); deflecting a portion of the start wire (84) into the space (96); clamping the start wire (84) in the deflected position; completing winding of a coil (100) on the coil form (91); and repositioning the end of the start wire (84) through said coil (100). The method according to claim 8 wherein said deflecting step comprises moving the deflecting finger (60) against the start wire (84) and into the space (96). The method according to claim 8 including the step of positioning the start wire (84) into the clamp (82) after said deflecting step and prior to said clamping step. The method according to claim 8 wherein said repositioning step comprises capturing the start wire (84) in the wire hook (66) and moving the wire hook (66) and the end of the start wire (84) through the coil (100). The method according to claim 11 wherein the wire hook (66) is rotated through an angle for movement through the coil (100) and wherein the angle of rotation of the wire hook (66) is in the range of 90° - 180°. The method according to claim 8 wherein, prior to the clamping step, the coil form (91) and clamp (82) are moved relative to each other to position the start wire (84) in the clamp (82) in position to enable the wire hook (66) to capture the start wire (84). The method according to claim 8 wherein the start wire (84) is lightly clamped in the clamp (82) to permit movement of the start wire (84) in the clamp (82).

Inventors: ARNOLD RICHARD B, BARRETT EUGENE R, ARNOLD, RICHARD B., BARRETT, EUGENE R.
Applicants: ADVANCED MACHINE & TOOL, GEN ELECTRIC, ADVANCED MACHINE & TOOL CORPORATION, GENERAL ELECTRIC COMPANY
Application year: 1991
Main classification: H02K15
IPC codes: H02K15