US2949554A - Method of winding a lap winding - Google Patents

Description

m m m m ..J. M. BIDDISON METHOD OF WINDING A LAP WINDING s Sheets-Sheet 1 Aug..l6, 1960 Original Filed May 5, 1953 o M o o I a IN N m9 mm. mom .m o I I N I O mom 9mm vmm mmm 0mm Aug. 16, 1960 v J. MBIDDISO 7 I 2,949,554

METHOD OF WINDING A LAP WINDING Original Filed May s. 1 55 s Sheets-Sheet 2 J Illl Aug. 16, 1960 J. M. BlDDlSON METHOD OF WINDING A LAP WINDING Original Filed May 5, 1953 7 8 Sheets-Sheet 3 SEA 8 Sheets-Sheet 4 In 00m mom .,o 9 +3 8 w En 4% oft 0J won \mfi a om won m: mom 0 N: mm

Aug. 16, 1960 J. M. BIDDISON METHOD OF'WINDING A LAP WINDING Original Filed May 5, 1953 Aug. 16, 1960 J. M. BIDDISON 2,949,554

METHOD OF WINDING A LAP WINDING Original Filed May 5, 1953 8 Sheets-Sheet 5 IN VTOR.

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Aug. 16, 1960 J. M. BIDDISON METHOD OF WINDING A LAP WINDING Original Filed May 5. 1953 8 Sheets-Sheet 6 Aug. 16, 1960 J. M. BIDDISON 2,949,554

METHOD OF WINDING A LAP WINDING Original Filed May 5, 1953 8 Sheets-Sheet '7 IN VEN TOR.

Aug. 16, 1960 J. M. BIDDISON 2,949,554

METHOD OF WINDING A LAP WINDING Original Filed May 5. 1953 8 Sheets-Sheet 8 IN VEN TOR.

Patented Aug. 16, 1960 METHOD OF WINDING A LAP WINDING John M. Biddison, Dayton, Ohio, assignor to Harry W. Moore, Dayton, Ohio Original application May 5, 1953, Ser. No. 353,160. Divided and this application Apr. 4, 1956, Ser. No. 576,193

2 Claims. Cl. 310-206 This invention relates to a method of winding a single layer lap winding utilizing an armature winding machine, the arrangement of the windings and the method of winding the same, and more particularly to a coil winding and machine for winding same wherein successive coils are wound in reverse direction, although not neces sarily so limited. This is a division of my application Serial No. 353,160, filed May 5, 1953, for Coil Winding Machine, now abandoned.

In the manufacture of armatures, at times it is desirable to use a double wire, so as to form two coils side by side arranged in parallel.

An object of this invention is to provide an armature winding device wherein two pairs of double coils are wound or laid in the slot simultaneously, that is, two wires are laid in the same slot side by side simultaneously so as to form a single layer lap winding.

Another object of this invention is to provide a groove forming mechanism that forms at least two series of loops, the loops of one series being longer than the other.

Other objects and advantages reside in the construction of parts, the combination thereof and the mode of operation, as will become more apparent from the following description.

In the drawings,

Figure 1 is a top plan view of a major portion of the machine, the parts being broken away that did not go on this sheet.

Figure 2 is a side elevational view with parts in section.

Figure 3 is a fragmentary cross sectional view, taken substantially on line 33 of Figure 2.

Figure 4 is a front elevational view with parts broken away and other parts shown in section.

Figure 5 discloses the wire reeling and tensioning mechanism used in connection with this machine, showing the case in section.

Figure 6 is a fragmentary side elevational view, disclosing the armature removing mechanism.

Figure 7 is another view similar to the one shown in Figure 6 with the armature removing mechanism shown in the position after an armature has been removed.

Figure 8 is a cross sectional view of the armature engaging mechanism and a portion of the spinner drive mechanism.

Fi ure 9 is an enlarged end view of the armature showing schematically one coil consisting of double Wires laid in a pair of slots.

Figure 10 is another cross sectional view of the chucks for holding the armatures and the driving mechanism for the spinners.

Figure 11 is an enlarged fragmentary detail view, taken substantially on line 11-11 of Figure 10.

Figure 12 is a schematic wiring diagram of the windings in the armature.

Figure 13 discloses a series of cams mounted upon the common cam shaft used in actuating the various switches controlling the circuit in the coil winding machine.

Figure 14 discloses a loop forming member and a spinner as the spinner passes this member preparatory to reversal.

Figure 15 is a view similar to Figure 14, wherein the wire has passed the loop forming member at about the time that the spinner has come to rest.

Figure 16 discloses another view of the loop forming member in the position it assumes when the spinner has advanced through an angle of from the position shown in Figure 15.

Figure 17 discloses another loop forming member mounted in the path of the wire immediately after the armature is indexed for forming a short loop.

Figure 18 is a view similar to Figure 17 showing the initial step of forming the loop.

Figure 19 discloses the loop forming member shown in Figure 18 after the spinner has advanced through an angle of 180 from the position shown in Figure 18.

In the past, it has been customary to Wind all coils on an armature in the same relative direction. When an armature winding machine has been used, it has been customary to have the spinners rotate in the same direction for each succeeding coil, or, in the event the armature is rotated on the wire fed from a stationary supply, the armature has generally been rotated in the same direction. Furthermore, in the winding of some types of armatures, two or more coils are laid in the same slots and parallel to each other. Instead of winding the succeeding coils in the same direction and instead of winding two separate coils in the same slots, two wires are wound into the slots simultaneously. This has been accomplished by providing a winding mechanism which winds two wires simultaneously on each of the spinners, there being two spinners, four wires are wound simultaneously. Two of the Wires are laid in one pair of slots and the other two wires are laid in another pair of slots. The wires are fed from separate spools. A guiding mechanism has been provided for the wires which permits the wires 'to be fed from the spools twisted slightly while passing through the guiding mechanism without twisting the wires when they are laid in the slots.

In order to provide leads from the ends of the coils, loops are formed at the ends of the coils and in some cases loops are formed in the center of the coil. When two sets of loops are formed, one loop is longer than the other for the purpose of identification. If the coils do not have center taps, coils in succeeding slots are wound in opposite directions, that is, the spinners rotate in one direction when winding one pair of slots. When the succeeding pair of slots are brought into registry, the spinners are driven in the opposite direction. In the event the coils in a pair of slots are provided with center taps, one half of the coil is wound in one direction and the other half in the opposite direction. This has been accomplished by use of a rack and a pinion, the rack oscillating so as to drive the pinion first in one direction and then in the opposite direction. A detailed description of the mechanism used in accomplishing this result will now be made.

Referring to the drawings, a cabinet forms a base for the coil winding mechanism. This cabinet is also used as a housing for some of the controls and pneumatic hydraulic cylinders, and a housing for the prime mover, consisting of an electric motor 22. The electric motor 22 actuates a shaft 24 through a suitable gear reducing mechanism, so as to acquire the desired speed for the shaft 24. The speed of the motor may also be adjusted by a suitable control mechanism that has not been shown, in that any suitable type of control mechanism for a motor may be used. The shaft 24 has mounted thereon a crank arm 26 carrying a crank pin 28 having pivotally mounted thereto a rack 30 provided with teeth 32. The teeth 32 of the rack 30 mesh with a pinion 34 keyed to a drive shaft 36. A floating connecting unit includes a pair of plates 38 held in fixed spaced relation by a plurality of bolts 40 passing through aper tures in the plates 38 and through the center of tubular members 42. The plates 38 support bearings 44 mounted for rotation upon the shaft 36, there being one bearing 44 on each side of the pinion 34 that is keyed by a key 46, as best seen in Figure 3, to the shaft 36. The rack 30 is provided with a pair of oppositely disposed channels 48 extending through the major length of the rack 30.

A pair of rollers 50 is mounted for rotation on suitable pintles 52 seated in suitable apertures in the plates 38. The plates 38 also support a pair of rollers 54 mounted upon pintles 56, the rollers 54 being arranged in spaced relation and engaging the top of the rack 30, as viewed in Figure 2. The rollers 50 and 54 cooperate to guide the rack 30, so as to cause the teeth 32 to mesh with the teeth on pinion 34. The plates 38 oscillate upon the shaft 36, in that the crank arm 26 when rotating causes the one end of the rack to travel through a circular path.

As is well known to those skilled in the art, the velocity or speed of the rack 30 may be represented by the sine wave curve. Whenever the rack 30 is in alignment with the crank arm 26, that is, when the crank arm 26 passes through dead center, the velocity of the rack 30 immediately prior to and after the crank arm passes through dead center is very slow. When the crank arm 26 forms a right angle with respect to the rack 30, the rack 30 travels at the maximum speed or velocity. This characteristic of the movement of the rack results in a very desirable movement as far as the coil winding machine is concerned, as will appear more fully later.

The shaft 36 extends across the coil winding machine and in spaced relation from the top of the cabinet 20. It passes through two gear boxes or gear casings 60 and 62. As may best be seen by referring to Figure 8, the gear casing 62 contains a chain of gears including a gear 64 and a ring gear 66 mounted upon a tubular sleeve 68 and fixedly attached thereto by a series of bolts 70. The tubular sleeve 68 is mounted in friction bearings 72, having the outer races seated in the walls of the gear casing 62 and the inner races mounted in rabbets adjacent the ends of the tubular sleeve 68. A tubular shaft 74 is non-rotatably mounted in the sleeve 68; but mounted for axial movement therein, so that the tubular shaft 74 may be moved endwise independently of the tubular sleeve 68. This has been accomplished by providing a pair of keys 76 seated in the keyways in the periphery of the tubular shaft 74 and mounted for sliding movement in suitable slots in the tubular sleeve 68.

The endwise movement of the tubular shaft 74 is accomplished by a hydraulically driven arm 80 terminating in yoke engaging pintles in a bearing support 82 supporting an anti-friction bearing 84, having the outer race seated in the support 82 and the inner race positioned near the end of the tubular shaft 74 and held in position by suitable key rings 86 and 88. The arm or lever 80 is pivotally mounted at 8-1 and is oscillated about the pivot 81 by a hydraulic cylinder 83 mounted in the casing and having piston rod 85 connected to the end of the arm or lever 80 at 87. The inner end of the tubular shaft 74 supports a bracket clamped in position by a suitable bolt 92. This bracket 90 has mounted therein a wire guide pulley 94 journalled upon a stubshaft 96. The bracket 90 terminates in a stub pintle $8 rotatably supporting a spinner head by means of suitable anti-friction bearings. A fiber friction disc 102 is mounted between the end of the bracket 90 and the spinner head 100. A flier" rod 104 is secured to the bracket 90 and rotates therewith. This flier rod supports a wire guide wheel or pulley 106 adjacent the outer end thereof and a wire guide or shield 108. The winding or spinner head 100 is provided with an arcuate seat 110 adapted to be seated against the periphery of the laminations of an armature 112.

A pair of wires are fed from a suitable supply package, through a tensioning device disclosed in Figure 5, which will be described more fully later, over a pair of wire pulleys 120, best seen in Figure 11, rotatably mounted upon the stubshaft 122, mounted in a pair of arms 124 integral with a capping member 126 secured to member 82. The capping member 126 is provided with a pair of apertures 128, one for each wire 130. The wires 130 are fed through the tubular shaft 74, so as to be fed over the pulleys 94 and the pulleys 106 to the armature slot. Due to the fact that the shaft 74 must rotate in order to wind the coil, it is necessary to provide some kind of guide means for the wires, so as to prevent twisting of the Wires.

This guide means includes a pair of springs 140, one for each aperture 128, the outer end of the springs terminating in a loop held in position by a suitable screw 142. The inner ends of the springs 140 are secured to a capping member 144 fixedly mounted in the inner end of the tubular shaft 74. These springs may be used for guiding the wires, in that the springs will twist and wind upon each other, so as to provide two substantially helical paths for the wires. If, for example, three loops or three turns are used in each coil, the springs 140 are then so attached that in winding the three layers they first unwind one and one-half turn and then Wind up in the opposite direction one and one-half turn, making a total of three turns all told. In other words, the movement of the inner end of the springs is limited to 540. This type of a guide mechanism serves the purpose when only a few turns are used in each coil.

The gear casing 60 contains gears similar to the gears enclosed in the gear casing 62, with the exception that in one of the casings there is an additional gear in the chain of gears, so that the shafts 148 and 74 rotate in opposite directions, the shaft 148 being journalled in the gear casing 60 in a manner identical to that disclosed in connection with the shaft 74. The shaft 148 supports a bracket 150 similar to the bracket 90, this bracket 150 having mounted therein a pair of wheels 152 over which the wires are guided and its flier 154 having mounted thereon a pair of guide wheels 156 and an overlapping shield 158. One wire passes over one wheel 152 and one wheel 156. The other wire passes over the other wheel 152 and the other wheel 156. The inner end of the bracket 150 terminates in a pintle 160, supporting by means of a suitable bearing a winding head 162. This winding head is provided with an arcuate surface 163 adapted to engage the armature laminations on a side diametrically opposed to the portions of the laminations engaged by the arcuate surface 110 of the winding head 100.

The winding head 162 is provided With an indexing mechanism that includes a pawl 164 mounted for reciprocatory movement in a slot 166 normally biased towards the rotor or armature teeth by a leaf spring 168 and biased to a down position, as viewed in Figure 8, by a compression spring 170. Before initiating the winding of an armature and at the completion of the winding of each pair of coils, a stinger or plunger 180, hydraulically driven from a hydraulic cylinder 184, projects upwardly into engagement with a pawl actuating plunger 182, so as to rotate the armature 112 through an angle corresponding to the angular spacing of the armature slots. However, before the indexing operation takes place, it is necessary to separate the winding heads 1110 and 162 a short distance, so as to release the pressure upon the armature 112. This has been accomplished by momentarily energizing the hydraulic cylinders 83, separating the winding heads a short distance. Immediately upon the armature being indexed, the winding heads are moved towards each other again, so as to clamp the armature in position with two pairs of slots in registry with the winding surfaces of the winding heads 100 and 162.

As soon as the winding heads have been separated slightly, the stinger 180 is projected upwardly, so as to engage the plunger 182 actuating the pawl 164, causing it to engage the margins of the adjacent slot. As the pawl advances upwardly, the armature is rotated in a clockwise direction, as viewed in Figure 8, the stinger 180 pushing the plunger upwardly the exact distance required to advance succeeding pairs of slots into registry with the winding surface of the winding heads 100 and 162. The timing of the driving mechanism is such that immediately upon the armature being actuated into registry, the winding heads are again advanced toward each other, so as to rigidly hold the armature in position. The stinger 180 drops down into its home position. The slight separation of the winding heads, the indexing of the armature, the clamping of the armature and the withdrawal of the stinger all take place While the crank arm 26 passes through dead center, at which time the rack 30 moves very slowly. As a matter of fact, at one instant it actually stands still.

The fliers 104 and 154 will now rotate in the opposite direction, so as to wind the succeeding pair of coils in the opposite direction of the winding of the immediately preceding coils. When this reversal takes place, a loop is formed between the adjacent coils by a loop forming mechanism which will now be described.

Due to the fact that the direction of rotation of the fliers is reversed after the winding of each coil, so that the succeeding coils wound by a. particular flier are wound in opposite directions, it is necessary to provide some method of identifying the coils that are wound in a clockwise direction by a flier and those that are wound in a counterclockwise direction by the same flier. This has been accomplished by forming a long loop at the end of each coil wound in one direction and a short loop at the end of each coil wound in the opposite direction. This is for convenience in identifying the coils when connecting the ends of the coils to the commutator segments of the armature.

Two separate pairs of hooks or loop forming members are used to form the loops in the ends of adjacent coils. The mechanism for forming the short loops will first be described. This has been accomplished by the use of substantially L-shaped brackets 230 attached to the winding heads and projecting rearwardly. Substantially bellcrank shaped hooks 232 have been pivotally attached to the ends of the L-shaped brackets 230. These bell-crank shaped hooks are normally biased toward the normal path of the wire 130, as shown in Figures 14 to 19 inclusive. However, the wire 130 normally clears the hook end of the bell-crank hooks 232. When a coil has been wound and the hooks 208 and 210 do not project into the path of the wires 130, the wire 130, upon the armature being indexed, will emanate from the curved portion of the winding head and will traverse the hook end of member 232, so as to form a loop, as shown in the successive steps disclosed in Figures 17, 18, and 19.

The bell-crank lever 232 is provided with a little projection 233 that prevents the wire from slipping off of the end of the bell-crank lever 232. In Figure 17 it shows the path of the wire immediately after the armature has been indexed and at the time that the flier 154 is beginning to move in the opposite direction, that is, downwardly and around, as viewed in Figure 17. The wire is caught upon the long arm of the bell-crank lever 232 and prevented from slipping off of the end by the small projection 233. In Figure 18, the long loop has been released, which loop forms the center tap of the previous coil, which will be described more fully later.

Figure 19 shows the flier 154 after it is rotated through 180, at which time a loop has been formed and held by the projection 233. A spring 235, attached to the short end of the bell-crank lever 232, permits a slight oscillation of the bell-crank lever 232 in a clockwise di rection from the position shown in Figure 18 to the position shown in Figure 19. This is caused by the tension of the wire. This movement of the bell-crank lever 232 in a clockwise direction, as viewed in Figures 18 and 19, removes the loop from the normal path of the wire as the first half of the succeeding coil is Wound. As soon as the first half of the succeeding coil has been wound, a long loop is formed, which will now be described.

This mechanism includes a fixed support 200 mounted upon a raised portion 2912 upon the cabinet 20. This fixed support 269 has mounted thereon a hydraulic cylinder 264 provided with a piston rod supporting a movable support 286 having mounted thereon a pair of hooks 208 and 210 by means of suitable screws 212, as best seen in Figures 1, 6 and 7. The succeeding steps of operation have been shown in Figures 14, 15, and 16, where only one of the hooks has been shown for the sake of clearness, namely, hook 268. The hook 210 has been omitted; but it would operate in the same manner as hook 208, excepting that it would be located below the support 206. In Figure 14 it shows the wire that is actuated by one of the fliers clearing the end of the hook 208. In Figure 15 support 206 has been actuated toward the armature and at the same time a hydraulic cylinder 220 has actuated a movable support 222, having pivotally mounted thereon a pair of links 224 and 226. The link 224 is connected to an extension on member 2025 and the link 226 is attached to an extension on member 210. The hydraulic cylinder 220 actuates the links 224 and 226 in a direction toward the armature, so as to cause members 208 and 210 to swing into the path of the wire 130. When this takes place and the fliers reverse their direction of rotation, the small hooks on the ends of members 268 and 210 engage the wire and as the support 206 is retracted from the extended position into the retracted position shown in Figure 16,,the hook 208 will then be moved toward the armature shaft. By retracting the links 224 and 226 into the position shown in Figure 1, it can readily be seen that the loops of wire will be located in close proximity to the armature shaft and out of the normal path of the wires 130 as coils are wound. The loops will be held in this position during the winding of the next pair of coils.

The pair of hooks and 210 operate to form loops functioning as center taps of each coil and the short hooks 232 operate to form loops on the ends of the coils. These operations continue cyclically until all of the slots in the armature have been wound with the required number of coils. in the event no center tap is used, the short loops will be formed between the ends of two adjacent coils and the long loops will be formed at the opposite ends of the coils. When the spinners begin rotating in the direction shown in Figure 17, the short loops will be formed. When the spinners begin rotating in the direction shown in Figure 15, members 2118 and 210 are actuated into the path of the wires and form the loops and move the loops inwardly towards the armature shaft before the wires come in contact with members 232.

As stated previously, the wires are tensioned by a suitable tensioning device shown in Figure 5. This tensioning device includes a standard 250 having mounted thereon a bracket 252 supporting a wheel 254 that maintains a uniform tension by means of an arm 256 applying a brake whenever a slack is found in the wire. This brake may operate similar to the device disclosed in the Kenneth A. Moore United States Letters Patent No. 2,643,075, issued iune 23, 1953, for Unreeling Device. The tension of the Wires is sufficient to tightly wind the coils in the respective slots.

Due to the large amount of tension used, difiiculty is encountered in withdrawing the armature from winding position. In order to release the tension of the wire, a hydraulic cylinder 260, provided with an armature 262 connected to a slotted head 264 having a slot straddling a pin 266 fixedly mounted in the arm 256, is actuated from the full line position shown in Figure into the dot-dash position shown in Figure 5, releasing the tension on the wire by rotating the arm 256 a sufiicient distance in a clockwise direction, as shown in Figure 5. There is some tension in the wire after the tension has been partially released, partly for the reason that the wire is rather stiff and furthermore, the wire, passing through the spring guides 140, offers a certain amount of resistance. That being the case, a suitable armature ejector mechanism has been provided. This armature ejector mechanism will now be described.

An L-shaped bracket 300 projects forwardly from the cabinet 20. This L-shaped bracket 300 supports a link 302 and a lever 304. The end of the link 302 and the end of the lever 304 have pivotally attached thereto a gripper jaw member 3%. This gripper jaw member 306 has pivotally attached thereto a bell-crank member 308, one arm of which forms another jaw member. A by draulic piston 310 is provided with a piston rod 312 pivotally attached to lever 304. This piston rod 312 has a considerable length and is light weight, so that it may flex sufiiciently to accommodate the curved path of its connection to the lever 364. In Figure 7 it shows the position of the armature ejector mechanism when an armature is being Wound.

As soon as the armature winding operation has been compelted, the piston 314D actuates the piston rod 312 so as to cause the jaw 306 and bell-crank member 308 to be actuated into a position to grasp the newly wound armature, as clearly shown in Figure 6. After it has been actuated into the armature grabbing position, a hydraulic or pneumatic cylinder 314, attached by an L-shaped bracket 316 to jaw member 306, is energized, so as to actuate a plunger 318, which in reality is the piston rod, into engagement with the lower arm of member 308 to rigidly clamp the armature between the jaw 306 and bell-crank member 3%. The two jaws are held in gripping position while the piston rod 312 is moved out Wardly or forwardly by the piston 310, so as to actuate the jaws 306 and 308 into the position shown in Figure 7. After the jaws have been actuated into this position, the jaws are disengaged. The wires used in winding the coils are not severed after each armature is wound, so that the wound armatures form a string of armatures, as clearly shown in Figure 7.

As soon as the armature has been ejected from winding position into the position shown in Figure 7, the operator inserts a new armature into winding position. As soon as the new armature has been inserted into winding position and the start switch has been actuated by the operator, the winding heads are caused to clamp the armature in position, then the armature is released slightly, so as to permit the stinger 180 to rotate two pairs of slots into registry with the winding surface on the winding heads. The winding heads are then clamped against the armature, at which time the winding operation is again resumed, so as to wind a series of coils cyclically into the various pairs of armature slots until until all of the armature slots have been properly wound,

a proper loop being formed between the coils on the armatures, as shown schematically in Figure 12, where the long loops have been indicated by the reference numeral 330 and the short loops indicated by the reference numeral 332.

The coil winding machine operates cyclically, which operation is controlled by a series of cams 400 mounted on the shaft 24 actuating micro-switches 402. Figure 13 discloses a schematic view of cams used in actuating micro-switches. The use of cams and micro-switches for controlling fluid circuits has been disclosed and described in my United States Letters Patent No. 2,670,145, issued February 23, 1954, for Armature Winding Machine.

A schematic diagram of a portion of the armature winding has been shown in Figure 12. Succeeding coils or coil segments are wound in opposite directions. By properly connecting the ends of the wires to the commutator segments, the electric current flows in the proper directions through the armature windings. It is immaterial whether the armature is used in a motor or in a generator as far as the method of winding is concerned. In the event each coil has a large number of turns, it would then be necessary to provide a suitable mechanism for rotating each pair of supply packages, first in one direction and then in the opposite direction, so as to prevent twisting of the wires. In that event, the spring guides would be omitted. It is to he noted that in Figure 12 a Wire has been returned through an adjacent slot.

After the armature has been completely wound, the loops are severed so as to form leads extending from the ends of the coils, the leads of alternate coils being reversed to reverse the polarity of those coils, to thereby cause the direction of the current flow through adjacent coils to be in the same direction. This procedure is the same whether one, two or more wires are laid simultaneously. In the event two or more wires are laid simultaneously in the slots, the separate wires in reality form separate coils. However, in connection with the description of the reversal of polarity, all of the wires laid simultaneously in a pair of slots is considered as one coil as far as the description of the method of reversing the polarity of every other coil is concerned.

Although the coil winding machine has been shown and described in connection with an armature, the same machine could he used in winding certain types of other forms, such as stators, it being expressly provided that the use to which the windings are to be put is not to be construed as a limitation, but merely for the purpose of illustration.

Although the preferred embodiment of the device has been described, it will be understood that within the purview of this invention various changes may be made in the form, details, proportion and arrangement of parts, the combination thereof and mode of operation, which generally stated consist in a device capable of carrying out the objects set forth, as disclosed and defined in the appended claims.

Having thus described my invention, I claim:

1. The method of winding a single layer lap winding in the slots of an armature, said method including the steps of winding adjacent coils in opposite directions, forming commutator connection loops between adjacent coils, severing the loops to form leads adapted to extend from the ends of the coils to the commutator, and reversing the commutator connection leads of alternate coils as a preliminary to making commutator connections.

2. The method of winding 2. single layer lap winding in the slots of an armature according to claim 1, wherein the loops of one set between adjacent coils are longer than the loops of the other set between the remaining coils, severing the loops of one set to form coil leads and severing the other set of loops to form C011 leads, connecting one set of leads directly and reversing the other set of leads to reverse the flow of current to one set of 2,949,554 9 10 coils thereof causing current to flow through all the coils OTHER REFERENCES In the Same dlrecnon' Arnold, E.: Die Wechselstomtechik, vol. 3, 3rd edition, References Cited in the file of this patent mills g g B gi ig 5 g rno 1e ere strorn ac me, v0 n e 1- UNITED STAKES PATENTS 5 tion, Julius Springer, Berlin, 1912, page 69, Fig. 79.

688,317 Lamme Dec. 10, 1901 Electric Motor Repair, Rosenberg, pages 52, 53, Figs. 1,742,112 Welsch Dec. 31, 1929 3-24, and 3-26, Murray-Hill Book, New York, 1946. 2,627,379 Moore Feb. 3, 1953 Croft, T. C.: Alternating-Current Armature Winding, 2,670,090 Crawley et-al. Feb. 23, 1954 McGraw-Hill, New York, 1924, pp. 2, 13, 14, 16, 25,

2,697,529 Hubbell 616-1 Dec. 21, 1954 26,33.

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