Abstract:
A pallet-based transportation system is provided for the fabrication of stators from multi-part inner subassemblies. The pallet has seating structures for holding an inner subassembly in an upright orientation, and fixtures for referencing the radial positions of poles. A lift mechanism operates though an aperture in the pallet to raise the seated stator subassembly and a suitable work position in a flyer-type wire coil winder. Movable wire guides in the winder have wire drop surfaces for controllably placing wire turns at specific locations in pockets adjoining the poles. Another lift mechanism raises and pushes inner subassemblies through a centering or aligning ring into matching outer casings.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     This application claims the benefit of U.S. provisional application No. 60/352,116, filed Jan. 25, 2002, and U.S. provisional application No. 60/374,675, filed Apr. 22, 2002. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to improved solutions for processing dynamo-electric machine components (e.g., armatures or stators for electric motors, generators, or alternators).  
         [0003]     Dynamo-electric machines include a rotating cylinder called the armature in a stationary part called the stator. The stator is a thick-walled tube (core or yoke) that surrounds the armature, which is also called the rotor. The stator has windings that produce a rotating magnetic field in the space occupied by the rotor. This magnetic field interacts, for example, with current passed through windings in the armature to generate forces that turn the armature. Conversely, when the armature is rotated by an external prime mover, the stator magnetic field induces a voltage in the windings.  
         [0004]     The armature and stator windings are wire coils wound on ferromagnetic pieces or cores (poles). These poles, for example, in the case of a stator, extend radially inward from the inner surface of the stator core or yoke. The radially inward extending poles usually have rectangular cross sections that fan or extend out into what are known as pole heads or shoes. Adjacent longitudinal slots formed along the inner surface of the stator core or yoke may define the poles. Alternatively, longitudinal ferromagnetic pieces (pole cores) may be mounted on the inner surface of the stator core or yoke. Conventional joining techniques, such as dovetail joints, may be used to securely mount the pole cores. The dimensional tolerances of the stator and the armature, the pole configurations, and wire coil-winding properties (such as wire size, pitch, number of turns) all contribute or determine the operational characteristics of the dynamo-electric machine.  
         [0005]     In stator manufacturing, the stator wire coils are often injected or wound using automated machinery that includes a wire dispenser or needle mounted on a moving arm. The wire dispenser travels back and forth through the stator bore alongside a pole, dispensing wire stretches that are deposited on the pole sides and ends to form a wire coil. However, such winding operations can be difficult, inconvenient or slow because of the limited geometrical access to the pole sides through the confines of a stator bore. The detrimental effect of the limited geometrical access for wire coil winding may be more pronounced for multiple-pole stators.  
         [0006]     Wire winding operations through the stator bores may be avoided by assembling stators using subassemblies, one of which has the pole sides extending out from an inner structure. Wire coils may be wound on such a subassembly from outside its bore using flyer-type winders that are conventionally used, for example, to wind armature coils. Becherucci et al. European publication EP 1020975, and Taguchi et al. U.S. Pat. No. 4,818,911 (both of which are hereby incorporated by reference in their entireties herein) disclose multi-pole stator subassemblies on which the wire coils may be wound by flyer-type winders.  
         [0007]     The two references respectively show single and two-section hollow annular inner casings (e.g., casing IC,  FIG. 1 ) made of tubular plastic material with receptacles or seats into which the pole cores (e.g., poles  70 ) may be installed. The pole cores may be installed in the seats through the hollow interior of the inner casing. Alternatively, the pole pieces may be inserted lengthwise in the seats in separated inner casing tube sections that are later closed over the inserted pole pieces. The inner casings have slots or pockets (e.g., pockets B) alongside the pole seats to accommodate wire coils. After the wire coils (e.g., coils WC) are wound in these pockets, the inner casing may be fitted in an outer casing (e.g., casing OC) to assemble a stator (e.g., stator S). In the assembled stator, the two casings are mechanically held together, for example, by interference fit of pole portions (e.g., dovetail pins DP) in suitable slots that are fashioned in the outer casing.  
         [0008]     Consideration is now being given to ways of providing solutions for improving dynamo-electric machine component manufacturing processes. Attention is directed toward methods and apparatus for assembling stators from subassemblies that permit stator wire coils to be wound using flyer-type winders, and in particular from subassemblies of the types similar to those described above.  
       SUMMARY OF THE INVENTION  
       [0009]     In accordance with the principles of the invention, methods and apparatus for the fabrication of dynamoelectric machine components from multiple parts or segments are provided. The inventive methods and apparatus may be used for improving the manufacturing processes used in making or assembling components from multiple part subassemblies.  
         [0010]     A pallet-based transportation system is provided for the fabrication of stators from multi-part inner subassemblies on which stator wire coils may be wound using flyer-type winders. The inner subassemblies are made from one or more plastic tube section and several stator pole pieces around which wire coils are wound. These multiple-part inner subassemblies may lack structural strength or rigidity until the final fabrication steps. Outer casings or support rings are fitted on the inner subassemblies to finalize the usable stator structure.  
         [0011]     The pallet for carrying multiple-part stator subassembly includes support or seating structures for holding the subassembly in an upright orientation, and fixtures for referencing the radial positions of stator poles in the subassembly. The support structures and the referencing fixtures are designed to hold the stator subassembly through all the fabrication stages involves in making the inner subassembly from plastic tube sections, stator poles, and wire coils.  
         [0012]     The seating or support structures and the radial position referencing fixtures are coaxial cylindrical structures that are disposed around an aperture in the pallet. The support structures have an inner ledge surface on which a stator subassembly can be seated in an upright orientation. The referencing fixtures are a circular array of spaced-apart vertical slats, which abut stator pole pieces in the seated in the uprightly seated stator subassemblies. The referencing fixtures may be detachable. The support structures and the radial position referencing fixtures provide structural strength and rigidity to stator subassemblies that lack the same.  
         [0013]     A lift mechanism operates though the aperture in the pallet to raise seated stator subassembly to a work position in a flyer-type wire coil winder. The lift mechanism includes an expanding collet whose clamps operate through the spacings in the circular array of the radial position referencing vertical slats to grip and firmly hold the stator subassembly poles. The lift mechanism presents the firmly held poles in proper alignment for wire coil winding by a winding head in the winder.  
         [0014]     A specific winding head can be used for winding wire coils in pockets adjoining the presented poles. The specific winding head includes a flyer arm and one or more pairs of movable wire guides. A pair of wire guides is shaped to include sloped wire-running portions extending into wire drop surfaces for controllably placing wire turns at specific locations in pockets. This pair of wire guides may be used for depositing layered and tightly wound wire coils. The other pairs of wire guides are utilized direct or guide wire dispensed by the flyer over geometrical obstructions into the pocket in which the wire coil is being wound.  
         [0015]     Another lift mechanism is used in conjunction with the pallet for compression fitting of the stator inner subassembly in the stator outer casing. Another lift mechanism includes a pair of movable press blocks on opposite sides of a centering ring. The centering ring and one of the movable blocks are designed to sandwich and hold the stator outer casing in an upright orientation. The other movable block is designed to operate from below the pallet to lift and push the stator inner subassembly into the sandwiched stator outer casing. The centering ring has tapered bore structure to align and radially compress the inner subassembly as it is pushed into the sandwiched stator outer casing. The tapered bore structure includes channels or grooves to receive dovetail pins or other locking structures on the surface of the inner casing. The channels or grooves are designed to align and direct the received dovetail pins or other locking structures into corresponding dovetail slots in outer casing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]     Further features of the invention, its nature, and various advantages will be more apparent from the following detailed description of the preferred embodiments and the accompanying drawings, wherein like reference characters represent like elements throughout, and in which:  
         [0017]      FIG. 1  is a simplified axial end view of a completed stator described in Becherucci et al. European publication EP 1020975. (For purposes of illustration, Becherucci et al.  FIG. 1  with renumbered elements is reproduced herein as  FIG. 1 ).  
         [0018]      FIG. 2  is a plan view of a pallet base with a support structure and a radial referencing fixture for transporting stator subassemblies in accordance with the principles of the present invention. The bottom tube section of a two-section inner casing is shown seated on the support structure.  
         [0019]      FIG. 3  is a cross sectional view of the pallet base and the inner casing bottom section shown in  FIG. 2 .  
         [0020]      FIG. 4   a  is a view similar to that in  FIG. 2 , additionally illustrating pole pieces installed in seats in the inner casing bottom section in accordance with the present invention. The inset in  FIG. 4   a  is an enlarged view of a pole piece illustrating, for example, dovetail pin and pole shoe shapes. An arrow directed from the inset figuratively indicates the installation of the pole piece in a seat.  
         [0021]      FIG. 4   b  is a cross sectional view of the structures shown in  FIG. 4   a.    
         [0022]      FIGS. 5   a  and  5   b  are views similar to those in  FIGS. 4   a  and  4   b , illustrating additionally the placement of the top tube section of the two-section inner casing to complete the fabrication of a stator inner subassembly on which wire coils may be wound using a flyer-type winder in accordance with the present invention.  
         [0023]      FIG. 6  is a partial plan view of the structures shown in  FIG. 5   b  with the stator inner subassembly sectioned in plane  2  ( FIG. 5   b ) to reveal details of the referencing fixture and a collet-like structure that is used to grip the subassembly in accordance with the present invention.  
         [0024]      FIG. 7  is sectional view of a lift mechanism that is used to raise the stator inner subassembly of  FIGS. 4   a - 5   b  to a work position in a flyer-type winding machine in accordance with the principles the present invention. The subassembly is shown at its raised position.  FIG. 7  also includes a side elevation view of the flyer-type winding machine.  
         [0025]      FIGS. 8   a  and  8   b  are enlarged sectional views of the top portions of the lift mechanism of  FIG. 7  prior to and after its engagement with the stator inner subassembly of  FIG. 5   b  in accordance with the principles of the present invention, respectively.  
         [0026]      FIG. 9  is an enlarged sectional view of the bottom portions of the lift mechanism of  FIG. 7  in accordance with the principles of the present invention.  
         [0027]      FIG. 10  is an enlarged sectional view of the top portions of the lift mechanism of  FIG. 7  illustrating details of the disposition of the stator inner subassembly in its raised position relative to a flyer arm of the winding machine in accordance with the principles the present invention. The flyer arm is shown partially in cross section.  
         [0028]      FIG. 11  is a view similar to that of  FIG. 10  of another flyer arm and wire guide system for depositing wire coils in the casing pockets that encircle the pole pieces in accordance with the principles the present invention.  
         [0029]      FIG. 12  is an enlarged view of area  2  of  FIG. 11 , illustrating the formation of a layered wire coil in accordance with the present invention.  
         [0030]      FIG. 13  is a plan section view as seen from directions  3 - 3  of  FIG. 11  illustrating an initial stage of the layered wire coil winding process.  
         [0031]      FIG. 14  is a perspective view illustrating the winding process, as seen from direction  4  of  FIG. 13 .  
         [0032]      FIG. 15  is a partial sectional view of a tool for compression fitting of the stator inner subassembly of  FIG. 5   b  in an outer casing in accordance with the present invention. The tool includes another lift mechanism for raising the stator inner subassembly, and guide members that direct subassembly pole pins into slots in the outer casing.  
         [0033]      FIG. 16  is view similar to that of  FIG. 15  illustrating the disposition of the lift mechanism and other tool components at a stage near the completion of the subassembly fitting operation in accordance with the principles the present invention.  
         [0034]      FIG. 17  is view similar to that of  FIG. 16  illustrating the disposition of the fitted stator assembly on the pallet base with the lift mechanism and the other tool components disengaged in accordance with the principles the present invention.  
         [0035]     In several of the accompanying drawings, which show sectional views, hatching or shading of various sectional elements may have been omitted for clarity. It will be understood that this omission of hatching or shading in the drawings is for the purpose of clarity in illustration only. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0036]     The present disclosure provides solutions for uniform and reproducible manufacturing of dynamo-electric machine components. The disclosed solutions relate to the processing of subassemblies that include multiple parts or segments. The disclosed solutions include inventive features to enhance control of the dimensions of fabricated parts. The inventive features may be built into the subassembly structures, their transport systems, and/or the processing tools. The disclosed solutions may find application in manufacturing processes where it is important to maintain the integrity of the geometrical configuration of the multiple parts in a subassembly during the processing steps.  
         [0037]     In order that the invention herein described may be easily understood, the subsequent description is set forth in the context of the manufacture of stators using multiple-part stator inner subassemblies or casings (see, e.g.,  FIGS. 1 and 17 ). It will, however, be understood that the invention is equally applicable to other types of multiple part subassemblies that may be used in the manufacture of dynamo-electric machine components and also to components of other types of machines. The multiple-part stator inner subassemblies or casings are used herein as illustrative workpieces. An illustrative stator inner subassembly or casing is an annular configuration of multiple stator pole pieces that are installed in longitudinal seats or receptacles that run lengthwise along the sides of a plastic tube. The inner casing subassembly may, for example, be similar to those described in Becherucci et al. European patent application No. 1020975, or Taguchi et al. U.S. Pat. No. 4,818,911. In particular, the inner casing may include a single plastic tube section or include two or more joinable plastic tube sections.  
         [0038]     A disclosed manufacturing solution includes transport systems, which preserve the geometrical configuration of multiple parts in a stator subassembly while advancing the stator subassembly from one processing step to the next. The transport systems use a pallet for carrying the multiple-part stator subassembly to work positions in various processing tools. An embodiment of the pallet for carrying the multiple-part stator subassembly is described herein, preliminarily in the context of the fabrication of a multiple pole stator inner subassembly or casing, with reference to  FIGS. 2, 3 ,  4   a ,  4   b ,  5   a ,  5   b  and  6 .  
         [0039]      FIGS. 2 and 3  show an exemplary pallet base  10  on which a bottom tube section  60   b  of a two-section inner casing tube  60  rests. Pallet base  10  may have a rigid plate-like construction, which can be transported on assembly line conveyor belts or rails  11  in a horizontal orientation. Pallet base  10  may be fabricated using, for example, a rigid plate  10   a . Subassembly support structure  12  is disposed on plate  10   a  to physically support stator subassemblies in a suitable upright orientation. Subassembly support structure  12  may, for example, be a hollow cylindrical fixture with a tub-shaped bottom that is seated in a circular cutout in rigid plate  10   a . The bore of support structure  12  is open at both ends. The lower bore end is open through an aperture in the tube-shaped bottom. Annular edge or rim portions  12 ′ of support structure  12  are suitably shaped to physically contact and support edge portions of upright stator subassemblies. Edge portions  12 ′ may, for example, be fashioned as an inner ledge in the cylindrical sides of support structure  12 . Bottom tube section  60   b  can rest in an upright or vertical orientation on the inner ledge. Portions of stator pole pieces  70  ( FIG. 4   a ) that may be inserted upright in the seats in bottom tube section  60   b  also may rest on the inner ledge. For example, portions of pole shoe  72  and/or pole pins  76  of inserted pole piece  70  may rest on the inner ledge.  
         [0040]     It will be understood that support structure  12  need not contact all end surfaces of a supported stator subassembly to maintain the latter in a desired upright position. Annular edge portions  12 ′ may be designed to be suitably discontinuous to accommodate various geometric aspects or features of stator subassemblies. For example, support structure  12  sidewalls (and edge portions  12 ′) may be broken as suitably spaced vertical sections or pillars. The pillar heights and the inter-pillar spacings may be suitably designed to accommodate the bottom portions of wire coils wound around stator poles  70  of an uprightly seated stator inner subassembly.  
         [0041]     In addition to edge portions  12 ′ of support structure  12  that are used to reference edge portions of an uprightly seated stator subassembly, pallet  10  includes a removable fixture  13  that serves as a radial position reference for parts of the supported stator subassembly.  
         [0042]     Fixture  13  may, for example, have a cylindrical structure that extends upward from pallet  10  through the annulus of support structure  12  and through the bore of any supported stator subassembly. The tubular sides of fixture  13  may, for example, be a circular array of spaced-apart slats or strips  13 ′. Adjacent slats  13 ′ in the array may be separated by a spacing or passageway  13 ′″. Passageways  13 ″ provide clearance for the operation of external workpiece-handling tools (such as collet clamps  24 ′  FIG. 6 ). Slats  13 ′ provide radial position references for poles  70  inserted in the seats in the inner casing tubes. Slats  13 ′ may be designed to abut portions of pole shoes  72  along the length of poles  70 . Abutting slats  13 ′ resist tilt, sag, or other position shifts by the inserted poles  70 , and thereby help preserve the geometrical configuration of the supported stator subassembly. An optional circular cap  13 ′″ that crowns upright slats  13 ′ may be used to structurally reinforce or stabilize fixture  13 .  
         [0043]     Fixture  13  may be releasably fastened to pallet  10  using conventional mechanical arrangements.  FIG. 3  shows an exemplary fastening arrangement using spring-loaded ball positioner  14 ′. Positioner  14 ′ is threaded in support structure  12  such that a spring-loaded fastening ball  14  is biased to center and releasably hold fixture  13  in support structure  12 .  
         [0044]     It will be understood that the various dimensions of a specific fixture  13  and a support structure  12  may be designed for use with stator subassemblies of specific size or type. Fixture  13  and support structure  12  on pallet  10  may be suitably replaced or changed to correspond to the particular size or type of stator that is being manufactured.  
         [0045]     Continuing with the description of the fabrication process of the multiple pole stator inner casing, reference is again made to  FIGS. 4   a ,  4   b ,  5   a ,  5   b  and  6 . In the fabrication process, bottom tube section  60   b  resting on support structure  12  of pallet  10  ( FIGS. 2 and 3 ) may be loaded with exemplary pole pieces  70 .  FIG. 4   a  schematically depicts the insertion of pole piece  70  in the seats or receptacles in bottom tube section  60   b .  FIG. 4   b  shows inserted pole pieces  70  in upright orientations abutting slats  13 ′. Next, pallet  10  may be moved on belts  11  to another workstation, for example, where a top tube section  60   a  can be lowered over inserted pole pieces  70 . As pallet  10  is moved, edge portions  12 ′ and slats  13 ′ preserve the upright orientation and the radial positions of inserted poles  70 . With inserted pole pieces  70  so aligned, top tube section  60   a  may be readily lowered over them ( 70 ) and joined with bottom tube section  60   b  to form a single tube  60 .  
         [0046]      FIGS. 5   a ,  5   b , and  6  show stator inner subassembly or casing  60  with the joined tube sections.  FIG. 6  additionally shows a workpiece gripper or collet that has been introduced in the bore of stator inner casing  60 . When biased by axial operation of plug  26 ′, collet clamps  24 ′ move through inter-pillar passageways  13 ″ of fixture  13  to contact the surfaces of poles  70 . Collet clamps  24 ′ are shown radially biased against pole pieces  70 .  
         [0047]     Multiple-pole stator inner casing  60  shown in  FIGS. 5   a  and  5   b  may be further transported on pallet  10  to a winding station. At the winding station, wire coils may be wound in casing pockets  62  that encircle poles  70  ( FIG. 6 ). A flyer-type winder may be used for the wire coil winding (e.g., winder  20 ′  FIG. 7 ). The inventive transport systems include workpiece loading and unloading apparatus (e.g., apparatus  23 ). Apparatus  23  may be used to move transported stator inner casing  60  from pallet  10  to a raised work position in flyer-type winder  20 ′. Features of apparatus  23  and its operation in conjunction with winder  20 ′ and pallet  10  are described herein, for example, with reference to  FIGS. 6, 7 ,  8   a ,  8   b ,  9  and  10 .  
         [0048]     Winder  20 ′ may have a winding head  52  for depositing a wire coil around any one of poles  70  of raised inner casing  60 . Optionally winder  20 ′ may include several winding heads for winding wire coils around several poles simultaneously (see e.g., Becherucci et al. EP 1020975). Exemplary winding head  52  includes a flyer  20  and winding guide  21  mounted on a shaft  22 .  
         [0049]     In operation, flyer  20  rotates on shaft  22  around one of poles  70  of raised casing  60  to deposit wire turns in pocket  62  adjoining the subject pole. During the operation, winding guide  21  is suitably positioned in alignment with subject pole  70  and flyer  20 , to direct wire dispensed by flyer  20  into pocket  62 . Shaft  22  also may be used to translate flyer  20  and winding guide  21  to and fro in directions  22 ′ and  22 ′ to deposit wire at different depths in pocket  62 . To facilitate this to and fro movement, winding guide  21  may have a suitable shape with hollow central portion or cutout abutting subject pole  70 . The central cutout, for example, cutout  21   c , permits unhindered movement of winding guide  21  in directions  22 ′ and  22 ″ over the ends of pocket  62  adjoining subject pole  70  ( FIG. 10 ). In the coil winding operations, shaft  22  translation may be suitably controlled to deposit wire turns in successive layers and obtain desirable stratification of the deposited wire coil.  
         [0050]     At the winding station, exemplary apparatus  23 , which may be used for lifting or raising inner casing  60  to the work position in winder  201 , is placed underneath pallet  10  ( FIG. 8   a ). Apparatus  23  includes gripping mechanisms for holding poles  70  that are seated in casing  60  in fixed positions during the winding operations. Apparatus  23  also includes an indexer for aligning poles  70  with winding guide  21  and flyer  20 . The indexer may be used, for example, to sequentially position poles  70  for wire coil deposition.  
         [0051]      FIGS. 8   a ,  8   b  and  9  show several components of apparatus  23 , namely support cylinder  24 , frame tube  25 , and central shaft  26 . The three components have concentric cylindrical structures with central shaft  26  and frame tube  25  as the innermost and outermost components, respectively.  
         [0052]     Support cylinder  24  has an expanding collet-like gripping structure at its upper end. The collet-like structure may be designed to grip and firmly hold multiple-pole stator inner casing  60 . Annularly spaced finger-like clamp portions  24 ′, which extend upwardly from tubular portions of support cylinder  24 , form the collet-like structure. The number of clamps  24 ′ may correspond to the number of poles  70  present in casing  60 . Each clamp  24 ′ may be intended to engage a corresponding one of poles  70 . Further, the collet-like gripping structure may be designed to operate through the common bores of inner casing  60  and fixture  13 . Accordingly, the diameter of the collet-like structures (unbiased) may be less than the inner diameter of fixture  13 . Additionally, the widths of clamps  24 ′ and the inter-clamp spacings may be designed so that clamps  24 ′ can freely move without interference through spacings  13 ″ between slats  13 ′ of fixture  13  ( FIG. 6 ). In operation, a frusto-conical shape plug  26 ′ on top of central shaft  26  may be used to engage clamps  24 ′ to bias them ( 24 ′) against poles  70  through spacings  13 ″.  
         [0053]     Lengths of support cylinder  24  below the collet-like structures also may have a diameter, which is smaller than the inner diameter of fixture  13 . In which case, the smaller-diameter lengths of support cylinder  24  also can pass through the bore of fixture  13 . Alternatively, lengths of support cylinder  24  below the length necessary to insert the collet-like structures up to the top of casing  60  may have a diameter that is larger than the inner diameter of fixture  13 . Support cylinder  24  shown herein, for example, in  FIGS. 7, 8   a ,  8   b  and  10 , corresponds to the latter alternative. Lengths of exemplary support cylinder  24  below ledge surface  24 ′″ have a diameter, which is small enough for passage into support structure  12  bore, but which is sufficiently large to disallow passage through (inner) fixture  13  bore.  
         [0054]     Apparatus  23  may be suitably configured so that the three concentric cylindrical components (support cylinder  24 , frame tube  25  and central shaft  26 ) can, individually or in various combinations, move vertically. Support cylinder  24  also may rotate. Conventional motor drive or actuator arrangements may be used to move the various components.  FIG. 9  shows an exemplary arrangement. In the exemplary arrangement, frame tube  25  is slidably seated in a vertical external tube  31 . (Support cylinder  24  and, central shaft  26  are seated in frame tube  25 .) External tube  31  is mechanically connected by sheet  31 ′ to vertical guides  31 ″, which, for example, are mounted on the frame of winder  20 ′. A linear actuator  35  drives guides  31 ″ (and attached external tube  31 ) up or down. Accordingly, support frame tube  25 , which rests in external tube  31 , moves up and down. Further, a horizontal enclosure  25 ′ is attached to the bottom end of frame tube  25 . A linear actuator  32  is mounted on sheet  31 ′ with its vertically movable shaft attached to enclosure  25 ′. By this attachment, frame tube  25  may move vertically relative to external cylinder  31  in response to actuator  32  actions. Also another linear actuator  33  is mounted on enclosure  25 ′. Actuator  33  is coupled to the bottom of central shaft  26  through coupler  34 . By this coupling, actuator  33  may push or pull central shaft  26  up or down in support cylinder  24 .  
         [0055]     Further, bearings  30  are mounted in frame  25  to enable smooth rotation of support cylinder  24  around axis X. A motor  29  is mounted on enclosure  25 ′ for controlled rotation of support cylinder  24 . Motor  29  may impart rotary motion to support cylinder  24  through the combination of meshed gears  28  and  24 ″ that are respectively mounted on a shaft of motor  29  and the bottom of support cylinder  24 . Gears  28  and  24 ″ are enclosed in enclosure  25 ′.  
         [0056]     In the operation using apparatus  23  to raise stator inner casing  60  from pallet  10  to the work position in winder  20 ′, a preliminary procedure involves firmly gripping casing  60  with the collet-like structure atop support cylinder  24 . In preparation of this procedure, with support cylinder  24  below pallet  10  ( FIG. 8   a ), shaft  26  is pushed up through cylinder  24  by actuator  33  so that clamps  24 ′ are in an unbiased state. Also, as needed, clamps  24 ′ may be radially aligned with spacings  13 ″ by turning support cylinder  24  using motor  29 . Next, linear actuator  32  raises frame tube  25  (with concentric structures  24  and  26 ) to insert unbiased clamps  24 ′ into the common bore of inner casing  60  and fixture  13  for engagement with pole shoes  72 . As the lengths of clamps  24 ′ are fully extended into the bore of casing  60  along its vertical axis, ledge surface  24 ′″ of support cylinder  24  may come in contact with the bottom end of fixture  13  ( FIG. 8   b ).  
         [0057]     With clamps  24 ′ in position adjacent to spacing  13 ″ in the bore of casing  60 , actuator  3 - 3  retracts or pulls shaft  26  downward so that frusto-conical plug  26 ′ engages and biases clamps  24 ′. Biased clamps  24 ′ expand radially outward and deflect through spacings  13 ″ to contact pole shoe  72  surfaces. By design expanded or deflected clamps  24 ′ radially press against pole shoes  72 , and thereby firmly grip inner casing  60 .  
         [0058]     In the operation to raise casing  60 , after the preliminary procedure for firmly gripping casing  60  with clamps  24 ′ is completed, actuator  35  drives guides  31 ″ upward. Consequently, frame tube  25  (which rests in external tube  31 ) and concentric inner structures  24  and  26  all move upward. Their upward movement lifts gripped casing  60  from pallet  10 . In the process, ledge surface  24 ′″ of support cylinder  24  pushes fixture  13  free of spring-loaded fastening ball  14 , and thus detaches fixture  13  from support structure  12 . Detached fixture  13  may rest on ledge surface  24 ′″ ( FIG. 10 ). Then further upward movement of guides  31 ″ driven by actuator  35  raises gripped inner casing  60  to a desired work position in vertical alignment with flyer  20 .  
         [0059]     Using another embodiment of apparatus  23 , stator inner casing  60  may be raised to the work position without having to detach and carry along fixture  13 . In this embodiment lengths of support cylinder  24 ′″ below the collet-like structures have a small diameter which permits passage into fixture  13  bore (not shown). After inner casing  60  has been firmly gripped by clamps  24 ′ ( FIG. 8   b ), support cylinder  24  is moved upward through suitably modified fixture  13  to raise inner casing  60  above fixture  13 . For this to happen fixture  13  may be modified to have a bore that is open at its top end. The modification may be obtained by using fixture  13  without optional cap  13 ′″ or removing cap  13 ′″ prior to lifting inner casing  60  from pallet  10 . In either case, inner casing  60  may be raised to the work position with biased clamps  24 ′ sliding up through fixture spacings  13 ″.  
         [0060]     Stator inner casing  60 , which has been raised using either embodiment of apparatus  23 , further may be rotationally indexed around axis X. Motor  29 , may be used to turn support cylinder  24  to index raised inner casing  60 . The indexing may, for example, sequentially present poles  70  one by one for wire coil winding by flyer  20 .  
         [0061]     For specific wire coil winding applications, specific winders (other than winder  20 ′ described above) may be used. A winder  120 ′, which has additional mechanical features for controlling the wire coil deposition in the pockets of raised stator inner casing  60 , is described herein with reference to  FIGS. 11, 12 ,  13  and  14 . Winder  120 ′ includes flyer arm  120  and a pair of wire guides, namely guides  100  and  101 . Wire guides  100  and  101  are shaped to include sloped wire-running portions or surfaces (e.g.  100   a  and  101   a , respectively) that smoothly extend into wire drop surfaces ( 100   b  and  101   b , respectively). Wire drop surfaces  100   b  and  101   b  may be vertical or almost vertical. Guides  100  and  101 , and flyer arm  120 , can translate in directions X 1  and X 2 , and also in directions Y 1  and Y 2 . Winder  120 ′ may also include optional pairs of supplementary wire guides namely guides  200  and  201 , and  300  and  301 . Other conventional parts or portions of winder  120 ′ may, for example, be similar to those of winder  20 ′. For clarity these conventional portions (e.g., frame, shafts, and drive mechanisms) are omitted from the FIGS.  
         [0062]     Winder  120 ′ may advantageously be used for depositing layered and tightly wound wire coils in pocket  62  adjoining subject pole piece  70  that has been indexed or presented for wire coil winding.  FIG. 11  shows a disposition of two guides  100  and  101 , and flyer arm  120  relative to pocket  62 . Guides  100  and  101  are respectively aligned with top end  62   top  and bottom end  62   bot  of pocket  62 .  
         [0063]     In the operation of winder  120 ′, flyer arm  120  rotates around axis  102  in direction D 1 , and dispenses tensioned wire W into coil pocket  62 . A length of tensioned wire W stretches from flyer arm  120  to that portion of a wire coil turn, which is already deposited or formed in coil pocket  62 . Guide portions or surfaces  100   a  and  101   a , cooperatively alternate in intercepting wire W as flyer arm  120  rotates around axis  102 . The intercepted wire W runs down portions or surfaces  100   a  (or  101   a ) and is dropped along terminal drop surfaces  100   b  (or  101   b ) into pocket  62 . The dropped wire is deposited in pocket  62  along the foot of the drop surfaces. Thus, wire turns may be deposited at specific locations in pocket  62  by aligning drop surfaces  100   b  and  101   b  with those specific locations. This operational capability of winder  120 ′ may be used to control the deposition of wire in pocket  62  and, for example, to wind wire coils in successive layers. The controlled deposition of wire coils in pocket  62  in successive layers may be advantageous in obtaining tightly wound coils and in achieving desirable high wire turn occupancy.  
         [0064]      FIGS. 12, 13 , and  14  show details of the formation of a layered wire coil in pocket  62 . In particular,  FIG. 13  depicts the winding state at the start of the deposition of the layered wire coil. The deposition of the first wire coil layer starts with a first wire turn (wt 1 ) deposited at the far or interior end of pocket  62 .  FIG. 12  depicts a later winding state in which the first layer (L 1 ) and a partial second layer (L 2 ) of the layered wire coil have been formed by wire turns wt. For convenient description, reference is first made to the later winding state shown in  FIG. 12 , and then to the earlier winding state shown in  FIG. 13 .  
         [0065]     The wire turns shown in  FIG. 12  may have been wound in pocket  62  by previous excursions of flyer  120  around axis  102 . Drop position Hi is located in pocket  62  at the foot of surface  100   b  (i.e., at a location below but slightly to the left of the vertical drop of surface  100   b ). Drop position Hi is adjacent to the most recently deposited wire turn in partial layer L 2 . In  FIG. 12 , wire W dispensed by flyer  120  is shown as being pulled or dropped over surface  100   b  in to position Hi at the foot of portion  100   b  to form the next turn in second layer L 2  of the wire coil.  
         [0066]     As the layered wire coil deposition process progresses, guides  100  and  101  (and flyer arm  120 ) are controllably moved laterally along directions X 1  (or X 2 ) to advance their foot positions (e.g., drop position Hi) to place the impending wire turn adjacent to the most recently deposited wire turn in a layer. For orderly buildup of the wire layer, the lateral guide and flyer movements, which may be continuous or intermittent, are synchronized with the rotational position of flyer  120  around axis  102 . Further, during the wire layer deposition, surfaces  100   b  and  101   b  may be positioned sufficiently close to the top surface of the partially deposited wire layer (e.g., layer L 2 ) to preclude the possibility of dropped wire slipping underneath surfaces  100   b  and  101   b  and over previously deposited turns (e.g., in area AW 1 ). It will be understood that if necessary or advantageous, outer or front sidewalls PS of pocket  62  may have suitable cutouts PA to provide clear passages for the lateral movement of guides  100  and  101  while keeping guides surfaces  100   b  and  101   b  close to the top surfaces of the developing wire coil ( FIG. 14 ).  
         [0067]     For a well-stratified multilayer wire coil, the first turn of an upper layer (e.g., layer L 2 ) may be placed vertically above the last or final wire turn of the preceding completed layer (e.g., layer L 1 ). To achieve this, after the final wire turn in the completed layer is deposited, the separation of guides  100  and  101  in directions Y 1  and Y 2  perpendicular to the plane of the completed layer may be increased. The increase may be calibrated to raise the bottom ends of guides  100   b  and  101   b  to the top of the new layer so that their respective drop positions (e.g., position Hi) are now on top of the final wire turn in a completed layer. Then the first turn of the new upper layer may be placed in the raised drop positions above the final turn of the completed layer. Subsequent wire turns in the new layer may deposited while moving the guide surfaces  100   b  and  101   b  laterally in directions X 1  (or X 2 ), as described previously.  
         [0068]      FIG. 13  shows the positions of the drop surfaces  100   b  and  101   b  at the initial stages of the formation of the first wire coil layer. In preparation for the wire coil winding, flyer  120 , and guides  100  and  101  may be moved in direction X 1  toward the center of inner casing  60  to positions over the innermost areas (R 1 ) adjacent to the back wall of pocket  62 . Drop surfaces  100   b  and  101   b  may be placed close to the back wall so that their respective drop positions (e.g., position Hi) are adjacent to the back-wall. Then a first wire turn wt 1  may be dropped or deposited adjacent to the back wall of pocket  62  by action of flyer  120  in the manner previously described. After first wire turn wt 1  is deposited, the first wire coil layer may be completely wound by placing successively adjacent wire turns in pocket  62  by moving flyer arm  120  and guides  100   b  and  101   b  laterally (in direction X 2 ) as described previously.  
         [0069]     In some winding applications, depending, for example, on specific stator geometry and dimensions or desired wire coil specifications, additional or supplemental wire guides also may be used. The supplemental guides may be used to direct or guide tensioned wire W in advantageous orientations to pocket  62 . The supplemental guides may, for example, be used to overcome geometrical obstructions in the path of wire W.  FIG. 13  shows, for example, pockets adjacent to subject pole  70  that interfere with a straight-line path of wire W extending from flyer arm  120  to area R 1  of pocket  62  adjoining subject pole  70 . The interfering adjacent pocket structures are likely to snag or catch wire W dispensed by flyer  120 . To overcome this interference, supplementary guides  200  and  201  may be positioned at the adjacent pole or pocket structures.  
         [0070]     In operation, supplementary guides  200  and  201  intercept wire W dispensed by flyer  120 . Suitably shaped running surfaces on the guides  200  and  201  redirect the intercepted wire toward pocket  62 . The intercepted wire may be redirected at suitable angles to the areas of pocket  62 , where guide portions  100   b  and  101   b  are located to deposit wire turns. This use of supplementary guides  200  and  201  prevents wire snagging or catching by the interfering adjacent pole structures and allows tensioned wire W to be pulled around the innermost areas (R 1 ) of pocket  62  at desirable pull angles by flyer  120 .  
         [0071]     Similarly, supplementary guides  300  and  301  may be used to guide or direct wire W to over come geometrical obstructions near the outermost areas (R 2 ) of pocket  62 .  FIG. 13  shows, for example, supplementary guides  300  and  301  positioned at borders PB of the outer or front structures of pocket  62 . Guides  300  and  301  prevent the front structures of pocket  62  from snagging or catching dispensed wire W. Also, suitably shaped running surfaces on the guides  300  and  301  allow redirection of wire W toward the outermost areas (R 2 ) of pocket  62 .  
         [0072]     After the winding operations (using, e.g., winder  20 ′ or  120 ′) are complete, stator inner casing  60  may be lowered to rest on support structure  12  on pallet  10 . The lowering process may be conducted by suitable operation of apparatus  23 . For brevity the lowering process is not described herein in any detail. However, it will be understood that the lowering process may, for example, generally proceed by suitably reversing some or all of the steps in the raising process described previously with reference to  FIGS. 7, 8   a ,  8   b , and  9 .  
         [0073]     Lowered stator inner casing or subassembly  60  with wire coils wound in pockets  62  around poles  70  may be transported on pallet  10  to a workstation for fitting or locking inner casing  60  in a matching outer casing or support ring  44 . Matching outer casing  44  may have complementary dovetail slots along its inner surface that match dovetail pins  76  extending radially from inner casing  60 . A press unit  40  may be used for press-fitting inner and outer casings  60  and  44  together. Features of press unit  40  and its operation in conjunction with pallet  10  are described herein with reference to  FIGS. 15, 16 , and  17 .  
         [0074]     With reference to  FIG. 15 , press unit  40  includes a movable pressing block  41  underneath a movable backing or counter block  42 . The two blocks are aligned facing each other along axis  401 . The two blocks may be used to press inner and outer casings  60  and  44  that are similarly aligned along axis  40 ′ together. Press block  41  may have a suitable shape conforming to the shape of portions of the lower surface of pallet  10 . For example, press block  41  may have a cup-like surface  41   b  conforming to the tub-like bottom surface of support structure  12  that extends below plate  10   a . The conformal contact surface  41   b  may be designed to ensure that during the operation of press  40 , block  41  presses or pushes casing  60  along axis  40 ′ with even or uniform pressure over the cross-section of casing  60 . Similarly, backing block  42  may have suitable shape for uniformly contacting outer casing or support ring  44 . For example, backing block  42  may have an annular seat or surface  42   b  conforming to the top surfaces of support ring  44 . The conformal contact surface  42   b  may be designed to ensure that during the operation of press  40 , block  42  presses against casing  44  along axis  40 ′ with even or uniform pressure over the cross-section of casing  44 .  
         [0075]     Press unit  40  also includes centering assembly  43 . Assembly  43  may have an annular or ring-like structure, which may have a tapered bore. Assembly  43  may be made up of matching half portions, namely movable members  43 ′ and  43 ″. Movable members  43 ′ and  43 ″ have open positions-away from axis  40 ′. Members  43 ′ and  43 ″ may close around axis  40 ′, for example, in the manner of a clamshell, or by other suitable motion. In their closed or ring-like configuration members  43 ′ and  43 ″ may support upright outer casing  44  in a cylindrical seat centered on axis  40 ′. Further backing block  42  may be lowered on outer casing  44  seated on closed members  43 ′ and  43 ″to firmly hold outer casing  44  in a fixed upright position. Conventional drive means (not shown) may be used to move the various block or members in press unit  40 .  
         [0076]     Members  43 ′ and  43 ″, include dovetail guide ways, channels, or grooves along their inner cylindrical surfaces (in closed position), which lead to the dovetail slots in uprightly seated outer casing  44 . The dovetail channels may be designed to suitably align and direct all dovetail pins  76  of casing  60  into corresponding or complementary dovetail slots of outer casing  44  seated on members  43 ′ and  43 ″. For example, upper channel portions  43   a  may have dovetail cross sectional dimensions that are the same or identical to the dimensions of the dovetail slots in outer casing  44 . Further, portions  43   a  may have a vertical orientation with channel sides aligned with the sides of corresponding dovetail slots in outer casing  44 . Lower channel portions  43   b  may have dovetail cross sectional dimensions that are larger or wider at the bottom opening, but which taper or grade down to the dimensions of upper portions  43   a  over the length of lower portions  43   b . Additionally, lower portions  43   b  may start at a greater radial distance from axis  40 ′ than vertical upper portions  43   a  and then slant or curve into the latter.  
         [0077]     In the operation using press unit  40  to fit and lock inner casing  60  in matching outer casing  44 , pallet  10  carrying the former is brought to rest over block  41 . Pallet  10  may be aligned so that the common central axis of support structure  12  and inner casing  60  coincides with axis  40 ′ ( FIG. 15 ). Matching outer casing  44  may be pre-positioned between block  42  and closed members  43 ′ and  43 ″, with its ( 44 ) dovetail slots aligned with corresponding channels  43   a  (not shown). Next, press block  41  may be raised to contact the underneath of plate  10   a . Further upward movement of press block  41  lifts pallet  10  up from belts  11 . The tub-like bottom portions of support structure  12  of lifted plate  10   a  may be seated or rest in matching cup-like surfaces  41   b  of block  41 . The conformity between the tub-like bottom portions and cup-like surfaces  41   b  may allow block  41  to support lifted plate  10   a  over a large area and keep the latter in a stable horizontal orientation with inner casing  60  aligned along axis  40 ′.  
         [0078]     As the upward movement of block  41  continues, channels  43   b  receive dovetail pins  76  of inner casing  60 . Received dovetail pins  76  are pushed up through channels  43   b  and  43   a . In the process channels  43   b  and  43   a  align received dovetail pins  76  and direct them into the corresponding dovetail slots of outer casing  44 . Aligned dovetail pins  76  slide into the corresponding outer casing dovetail slots as inner casing  60  is pushed up and pressed into outer casing  44  ( FIG. 12 ) by upward movement of block  41 . The slant or curved orientation of channels  43   b  leading to vertical channels  43   a  may allow for some radial compression of pole pins  76  and inner casing  60  as the latter are pushed up. This radial compression may advantageously allow tight-fitting inner casing  60  to slide into outer casing  44  smoothly.  
         [0079]     In an alternate fitting procedure using pallet  10  in conjunction with suitably modified press  40 , outer casing  44  may be pushed down over inner casing  60 . Press  40  may be suitably modified, for example, by enabling additional downward movement of members  43 ′ and  43 ″. In this alternative procedure, first, block  41  may be raised to firmly support pallet  10  carrying inner casing  60 . Matching outer casing  44  may be seated upright, sandwiched between block  42  and closed members  43 ′ and  43 ″. Then the entire upper assembly ( 42 ,  44 ,  43 ′ and  43 ″) may be lowered to push or press outer casing  44  over inner casing  60 . In this process, channels  43   a  and  43   b  may function in a manner similar to that described above to gather and direct dovetail pins  76  into corresponding dovetail slots in outer casing  44 .  
         [0080]     In either fitting procedure, after inner casing  60  is assembled or fitted in outer casing  44 , members  43 ′ and  43 ″ may be disengaged and returned to their open positions. Then block  41  may be activated to disengage or lower pallet  10  carrying the assembled stator casing to a rest position on belts  11 .  
         [0081]     One skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration and not of limitation. It will be understood that terms like “forward” and “backward”, “front” and “rear”, and other directional or orientational terms are used herein only for convenience, and that no fixed or absolute orientations are intended by the use of these terms.