Method for stripping windings from a stator

A method of stripping from a dynamoelectric machine stator a plurality of windings thereof having one of a pair of opposite generally annular grouping of end turns of the windings secured therefrom. The method includes the steps of: lowering the stator onto means for seating and supporting it so as to dispose the other of the end turns in a predetermined position; gripping the other end turns for maintaining them generally against displacement from the predetermined positions; and driving the seating means generally upwardly relative to the winding and moving the stator conjointly therewith toward a position displaced from the windings while gripping the other end turns in the predetermined position thereby stripping the windings from the stator.

BACKGROUND OF THE INVENTION 
This invention relates generally to the salvage of dynamoelectric machine 
components and in particular to a method for stripping windings from a 
stator for a dynamoelectric machine. 
Dynamoelectric machines, such as an electric motor or the like, are 
provided with a stator having a pair of opposite and generally parallel 
end faces intersected by a bore extending axially therebetween through the 
stator. A plurality of winding receiving slots are also provided in the 
stator about the bore thereof and intersecting with both the bore and the 
opposite end face. A plurality of windings generally respectively 
constituted by a preselected number of turns of copper or aluminum wire or 
the like are wound or otherwise inserted by means well-known in the art 
into the stator winding slots. In this manner, opposite sides of the 
winding turns are disposed within the stator slots, and opposite ends of 
the winding turns span across a selected number of stator slots adjacent 
the intersections thereof with the opposite end faces of the stator 
exteriorly thereof. These opposite ends of the winding turns are 
respectively formed into generally annular groupings extending from the 
opposite end faces radially outwardly of the stator bore and are known to 
the art as end turns. Of course, if desired, the particular wire of the 
windings may have an insulating coating thereon, and slot liners and 
wedges of suitable insulating material may be provided between the 
windings and the stator. Further, in some instances, the stators may be 
assembled by various means and methods generally well-known to the art as 
bonding. For a detailed discussion of one such bonded stator and method of 
assembly thereof reference may be had to U.S. Pat. No. 3,490,143 and U.S. 
Pat. No. Re. 26,788. 
In the past, wound stators, such as described above, which were found to be 
defective for one reason or another either at the time of manufacture or 
after usage, were stripped of their windings. In this manner, salvaged 
stators which were in condition for reuse were rewound, and those which 
could not be used were sold for scrap. Of course, the stripped windings 
could not be salvaged and were sold for scrap. In some cases, the entire 
wound stator may have been sold for scrap, but due to the formidable 
increases in stator core material, it is now more economically prudent to 
salvage stators for reuse if possible. 
In order to salvage stators, it is first necessary to sever one of the pair 
of opposite generally annular groupings of end turns of the stator 
windings therefrom, and various apparatus and methods have been employed 
in the past to sever one of the end turns from the stator windings. For a 
detailed description of one apparatus and method for severing end turns 
from stator windings reference may be had to U.S. Pat. application Ser. 
No. 541,740 filed Jan. 17, 1975. Further, various other apparatus and 
methods have been employed in the past to strip the windings from the 
stator after one of the end turns of the windings had been severed 
therefrom. 
In some of the past apparatus and methods for stripping a winding from a 
stator, the stator was clamped by suitable clamping means in a desired 
position atop a table or work bench or the like with the remaining end 
turns of the stator windings facing upwardly. Tongs were then engaged with 
a part of the remaining end turns, and the tongs were then driven or 
pulled upwardly by a hoist or the like. The upward movement of the tongs 
pulled the remaining end turns and windings therewith to effect the 
stripping of the windings from the stator. One of the disadvantageous or 
undesirable features of such past apparatus and method was that too much 
time was consumed and too many operations were involved in mounting or 
clamping the stator onto a work table in preparation for the winding 
stripping operation. Further, another disadvantageous or undesirable 
feature of such past apparatus and methods was that the tongs would not be 
operable to completely strip all of the windings from the stator in one 
pulling operation since the windings poles are separate; therefore, it 
might be necessary to strip each of the winding poles in separate pulling 
operations from the stator. 
In another of the past apparatus and methods for stripping the windings 
from a stator, the stator was first mounted to a fixture with the 
remaining end turns of the windings facing upwardly. A tool was then 
disposed on the upper end face of the stator having pins predeterminately 
disposed therein and adapted to be driven by a ram wedge generally 
radially outwardly to a displaced position interposed between the stator 
end face and each of the end turns of each of the winding poles. The 
stator and tool was then inverted on the fixture, and the tool was driven 
downwardly carrying the end turns of the stator windings on the displaced 
pins of the tool thereby to strip the windings from the stator. One of the 
disadvantageous or undesirable features of such past apparatus and method 
was that too much time was consumed and too many operations were involved 
with respect to tool placement and the inverting of the stator subsequent 
to the actuation of the tool for stripping the windings. Another 
disadvantageous or undesirable feature of such past apparatus and methods 
was that it may have been necessary to perform the stripping operation 
twice if the stator was provided with starting windings shifted in phase 
relation in the stator with respect to the running windings thereof. 
In yet another of the past apparatus and method for stripping windings from 
a wound armature for a dynamoelectric machine, a mandrel was provided on a 
drill press or the like, and the remaining end turns of the windings were 
slipped upwardly onto or about a free or lower end of the mandrel by an 
operator. The free end of the mandrel was tapered so as to, in effect, 
spread or displace the winding end turns as they were manually moved 
upwardly onto the tapered free end of the mandrel. Of course, when the 
engagement between the remaining end turns and the mandrel become great 
enough, the operator released the armature, and it was thereby suspended 
from the mandrel free end. The mandrel with the armature suspended 
therefrom was then lowered into a fixture, and a plurality of cams on the 
fixture were pivoted thereon to rotatably move fingers or prongs on the 
cam to position interposed between the upper end face of the armature and 
the remaining end turns. Of course, since there was no predetermined 
position of the armature in which the cam fingers engaged the remaining 
end turns, it was necessary to adjustably raise and lower the mandrel in 
order to effect the interposition of the cam fingers between the stator 
end face and the remaining end turns. Thereafter, the mandrel was lowered 
further driving the armature relative to the windings supported on the cam 
fingers toward a portion displaced from the windings thereby to strip the 
windings from the armature. One of the disadvantageous or undesirable 
features of this past apparatus and method was that it lacked a 
predetermined or mounting position of the armature in which the cam 
fingers could be positively engaged with the winding end turns. Another 
disadvantageous or undesirable feature of the past apparatus and method 
was that the mounting position of the armature to the mandrel was variable 
for each armature since it depended upon the particular shaping of the end 
turns. And still another disadvantageous or undesirable feature of this 
past apparatus and method was that the mandrel had to be adjustably raised 
and lowered so as to locate the cam fingers in the interstices between the 
remaining end turns and the stator end face thereby to consume too much 
time and effect too many separate operations. 
SUMMARY OF THE INVENTION 
Among the several objects of the invention may be noted the provision of a 
method for stripping windings from dynamoelectric machine stators which 
overcome the disadvantageous or undesirable features, discussed 
hereinabove, as well as others; the provision of such method in which the 
stator may be generally loosely mounted to means for seating and 
supporting it; the provision of such method and in which the stator is 
positively located on its seating and supporting means even though 
generally loosely mounted thereto; the provision of such method in which 
the remaining end turns of the stator are predeterminately positioned so 
as to be gripped upon the mounting of the stator to its seating and 
supporting means; the provision of such method in which the remaining end 
turns of the stator are peripherally gripped thereby to enhance the 
complete stripping of the windings from the stator in one stripping 
operation; and the provision of such method which is simplistic and, 
economical. Other objects and advantageous features of the invention will 
be in part apparent and in part pointed out hereinafter. 
In general, a method is provided in one form of the invention for stripping 
from a dynamoelectric machine stator a plurality of windings thereof 
having one of a pair of opposite generally annular groupings of end turns 
of the windings severed therefrom. In this stripping method, the stator is 
lowered onto means for seating it so as to dispose the other of the end 
turns in a predetermined position, and the other end turns are gripped for 
maintaining them generally against displacement from the predetermined 
position. The seating means is driven generally upwardly relative to the 
winding and the stator is moved conjointly therewith toward a position 
displaced from the windings while the other end turns are gripped in the 
predetermined position thereby stripping the windings from the stator.

Corresponding reference characters indicate corresponding parts throughout 
the several views of the drawings. 
The exemplifications set out herein illustrate the preferred embodiments of 
the invention in one form thereof, and such exemplifications are not to be 
construed as limiting in any manner. 
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now in general to the drawings, there is illustrated in one form 
of the invention a method for stripping from a dynamoelectric stator 11 a 
plurality of windings 13 thereof having one pair of opposite generally 
annular groupings of end turns 15, 17 of the windings severed therefrom. 
In this stripping method, stator 11 is lowered onto means, such as an 
arbor 19 or the like, for seating and supporting it so as to dispose the 
other of the end turns 17 in a predetermined position, and the other end 
turns are gripped for maintaining them generally against displacement from 
the predetermined position. Thereafter, the seating and supporting means 
or arbor 19 is driven generally upwardly relative to windings 13 and 
stator 11 is moved conjointly therewith toward a position displaced from 
the winding while other end turns 17 are gripped in the predetermined 
position thereby stripping the windings from the stator (FIGS. 2-4). 
More particularly and with specific reference to FIGS. 2-4, stator 11 has a 
bore 21 extending therethrough generally about an axis A and generally 
normal or perpendicular to a pair of opposite end faces 23, 25. A 
plurality of winding receiving slots 27 are provided in stator 11 
extending generally radially with respect to bore 21 and intersecting with 
both the bore and end faces 23, 25. Stator windings 13 are generally 
constituted by a plurality of turns or coils having opposite sides which 
are received in stator slot 27, and opposite end turns 15, 17 are integral 
with the opposite sides being formed in the aforementioned opposite, 
generally annular groupings adjacent stator end faces 23, 25 and spanning 
between a preselected number of the stator slots thereby to form with 
stator 11 a plurality of magnetic poles. If desired, windings 13 may be 
coated with a suitable insulating material, and slot liners 29 and slot 
wedges 31 of suitable insulating material may be disposed in stator slots 
27 between windings 13 and stator 11, as is well-known in the art. As 
previously mentioned, end turns 15 of stator windings 13 have been severed 
therefrom leaving a plurality of free ends 32 of the stator winding 
adjacent end face 23 of stator 11, as best seen in FIG. 3. 
Arbor or seating means 19 is provided with a generally radially extending 
flange 33 on which end face 25 of stator 11 is seated and supported in a 
mounting or mounted position when the stator is assembled to the arbor by 
an operator, and as the operator lowers the stator onto the arbor a 
guiding or locating surface 25 thereon engages stator bore 21. In this 
manner, the respective engagement of stator bore 21 and end face 25 with 
arbor guide surface 35 and flange 33 in the mounting position serves to 
predetermine the position of the other or remaining end turn 17 generally 
radially between and adjacent a generally annular abutment surface 37 for 
gripping engagement with a radially inner peripheral portion of the other 
end turn and a plurality of means, such as gripping bars 39, for gripping 
a radially outer peripheral portion of the other end turns. Gripping means 
or gripping bars 39 are respectively provided with a generally arcuate 
gripping surface 41 which, when engaged with the outer peripheral portion 
of other end turn 17, generally encompasses the entire periphery thereof, 
and it may be noted that the gripping surfaces are generally coplanar, as 
discussed in detail hereinafter. Gripping bars 39 are reciprocally driven 
by means, such as a plurality of air or hydraulic motors or the like 43 
shown in FIG. 1, to grippingly engage gripping surfaces 41 with the outer 
peripheral portion of other end turns 17 when stator 11 is in the mounting 
position, and the force of this engagement drives or displaces the other 
end turns generally radially inwardly into abutting or gripping engagement 
with annular abutment surface 37. In this manner, other end turns 17 are 
gripped in their predetermined position between annular abutment surface 
37 and gripping bars 39 in the mounting position of stator 11 and arbor 
19, and such gripping of the other end turns generally maintains them and 
stator windings 13 against displacement from the predetermined position or 
the mounting position of the stator and the arbor. 
With other end turns 17 so gripped between annular abutment surface 37 and 
gripping bars 39, means, such as another air or hydraulic motor 45 or the 
like shown in FIG. 4, for actuating or driving arbor 19 between its 
mounting position and its displaced position may be energized or operated 
to effect the reciprocal movement of the arbor in one direction from the 
mounting position thereof to the displaced position. Upon such driven 
movement of arbor 19, stator 11 is conjointly movable therewith toward the 
displaced position through the plurality of free ends 32 of stator 
windings 13 from which the one end turns 15 were severed and toward the 
displaced position thereby to strip the stator windings from stator slots 
27. It may be noted that the gripping of other end turns 17 in their 
predetermined position maintains them and stator winding 13 generally 
stationary in the mounting position when stator 11 and arbor 19 are moved 
relative thereto from the mounting position to the displaced position 
thereby to effect the stripping of the stator windings from the stator. 
Referring now again in general to the drawings, there is illustrated an 
apparatus, indicated generally at 47 (FIG. 1), for stripping from stator 
11 the plurality of windings 13 thereof with one of the pair of opposite 
generally annular groupings of end turns 15, 17 severed therefrom (FIGS. 
2-4). Apparatus 47 has means, such as arbor 19, movable between the 
mounting position and the displaced position for generally loosely seating 
stator 11 and supporting it in the mounting and displaced positions. 
Means, such as gripping bars 39 are provided for gripping engagement with 
other end turn 17 when stator 11 is in the mounting position to generally 
maintain windings 13 against displacement from the mounting position. 
Seating and supporting means or arbor 19 is movable from the mounting 
position in response to a force applied thereto to conjointly move stator 
11 relative to windings 13 to the displaced position thereby to effect the 
stripping of the windings from the stator when the gripping means, i.e., 
the annular abutment surface 37 and gripping bars 39, is engaged with 
other end turns 17. 
More particularly and with specific reference to FIGS. 1 and 4, apparatus 
47 is provided with supporting means, such as a base or generally flat 
plate or support 49 having a centrally located aperture or opening 51 
therethrough. A cylindric member or sleeve 53 is fixedly disposed or 
positioned on base 49 and generally coaxial with base opening 51 by a 
locating collar 55 which is fixedly attached by suitable means to the 
upper side of the base, and annular abutment surface 31 is provided on the 
cylindric member adjacent an upper end 57 thereof predeterminately spaced 
from the base. Arbor 19 has its flange 33 seated on upper end 57 of 
cylindric member 53 in the mounting position of the arbor and stator 11, 
and the cylindric member is so located that other end turns 17 extend 
predeterminately downwardly through the plane in which annular abutment 
surface 37 and gripping bars 41 are generally disposed when the stator is 
mounted to the arbor in the mounting position. It may also be noted that 
the engagement of locating surface 35 of arbor 19 with stator bore 21 when 
stator 11 is mounted to the arbor in the mounting position generally 
predeterminately disposes or positions the radially inner peripheral 
portion of other end turns radially about and at least in close spaced 
relation with annular abutment surface 37 on cylindric member 53. In this 
manner, arbor 19 locates other end turns 17 in their predetermined 
position so as to be gripped between annular abutment surface 37 and 
gripping surfaces 41 of gripping bars 39, as previously mentioned. 
A bearing housing 59 is arranged generally coaxially within cylindric 
member 53 and base opening 51 and extends through base 49 being attached 
thereto by suitable means. Bearing housing 59 guidably and slidably 
journals a shaft 61 for axial reciprocal movement therein generally normal 
or perpendicular to base 49, and arbor 19 is carried on an upper end of 
the shaft while a lower end thereof is drivenly coupled with air motor 45. 
Air motor 45 is disposed beneath base 49 and is connected for support by 
suitable means to the lower end of bearing housing 59. As well-known in 
the art, the stroke of air motor 45 may be adjustably limited thereby to 
predetermine the movement of shaft 61 and arbor 19 between the mounting 
position and the displaced position thereof. 
A plurality of means, such as guide blocks 63 of FIGS. 1 and 3, for sliding 
and guiding engagement with gripping bars 39, are mounted by suitable 
means to base 49 and spaced generally equidistantly from each other and 
from base opening 51. Gripping bars 39 and guide blocks 63 are 
respectively tongued and grooved so that reciprocal movement of the 
gripping bars may be generally radially directed toward and away from 
cylindric member 53 in a generally coplanar manner. It may be noted that 
the sliding and guiding engagement of gripping bars 39 with guide blocks 
63 serves to maintain gripping surfaces 41 of the gripping bars generally 
coplanar with annular abutment surface 37 of cylindric member 53. Air 
motors 43 are attached to base 49 adjacent guide blocks 63, and the air 
motors are drivingly coupled at 65 with the gripping bars for imparting 
the reciprocal movement thereto, respectively. A pair of assembly guards 
67 may be fixedly connected by suitable means (not shown) to base 49 
between adjacent pairs of buide blocks 63 for preventing wire of the 
stripped windings from being trapped behind gripping bars 39. 
OPERATION 
Prefacing the description of the operation of apparatus 47, it will be 
recalled that stators 11, prior to being loaded onto the apparatus, have 
had one of the end turns 15 severed therefrom, as illutrated in dotted 
lines in FIG. 3. Further, the various components of apparatus 47 are 
disposed in their mounting or at rest positions as shown in the drawings 
and as described hereinbefore. 
An operator for apparatus 47 may load stator 11 to it by manually lowering 
the stator onto arbor 19. As stator 11 is being so loaded, bore 21 thereof 
is positioned in a generally loose sliding and guiding engagement about 
locating surface 35 or arbor 19 and then further lowered on the locating 
surface until lower end face 25 of the stator is seated on flange 33 of 
the arbor, as illustrated in FIG. 3. With stator 11 assembled onto arbor 
19 in the mounting position thereof, the remaining or other end turns 17 
are automatically disposed in a predetermined position. In this 
predetermined or mounting position of other end turns 17, the other end 
turns extend generally through the plane in which is disposed annular 
abutment surface 37 and gripping surfaces 41 on gripping bars 39. In other 
words, the radially inner peripheral portion of other end turns 17 is 
disposed at least in close spaced relation about annular abutment surface 
37 and the radially outer peripheral portion of the other end turns is 
disposed adjacent gripping surfaces 41 of gripping bars 39, as previously 
mentioned. It may also be noted that stator 11 may be rather loosely 
mounted to arbor 19 in that only the weight of the stator maintains it 
against upward displacement from the arbor; however, it is contemplated 
that means could be employed to positively lock or retain the stator on 
the arbor against upward displacement within the scope of the invention so 
as to meet the objects and advantageous features thereof. Of course, the 
generally loose assembly of stator 11 to arbor 19, as mentioned above, 
greatly facilitates and simplifies the loading and unloading of the 
stators on apparatus 47. 
With other end turns 17 so disposed in their predetermined positions, air 
motors 43, as shown in FIG. 1, may be conjointly actuated to conjointly 
effect the reciprocal movement in one direction of gripping bars 39 in 
their respective guide blocks 63 to engage gripping surfaces 41 generally 
about the outer peripheral portion of other end turns 17, as shown in 
FIGS. 2 and 3. The forces so generated by air motors 43 and transferred 
through gripping bars 39 onto other end turns 17 deflects or urges the 
other end turns generally radially inwardly, as seen in FIG. 3, into 
abutting engagement with annular abutment surface 37. In this manner, when 
stator 11 is assembled to arbor 19 in the mounting position, other end 
turns 17 are tightly gripped between annular abutment surface 37 and 
gripping surfaces 41 which are generally coplanar, and the forces applied 
by air motors 43 are effective to maintain this gripping engagement of the 
other end turns thereby to prevent displacement of stator windings 13 from 
the mounting position. 
With other end turns 17 so gripped in their mounting position, air motor 45 
may now be actuated to apply a force onto shaft 61 and to effect upward 
axial movement of the arbor 19 with stator 11 assembled thereto from the 
mounting position to a displaced position wherein the arbor is disengaged 
from upper end 57 of cylindric member 53, as shown in FIG. 4. In this 
conjoint displacement movement of stator 11 and arbor 19 to the displaced 
position thereof, the stator is moved relative to its windings 13 which 
are maintained in the mounting position against displacement by the 
gripping engagement of annular abutment surface 37 and gripping surfaces 
41 with other end turns 17. Therefore, since windings 13 are held 
generally stationary in the mounting position and stator 11 is displaced 
relative thereto, the displacement of the stator moves it upwardly through 
free ends 32 of the windings from which was severed the one end turns 15, 
as previously mentioned, toward the displaced position of the stator. When 
stator 11 and arbor 19 are so concertedly moved to their displaced 
position, stator windings 13 are thereby stripped from stator winding 
slots 27. 
Upon such stripping of windings 13 from stator 11, air motors 43 may not be 
deactuated to effect retraction of gripping bars 39 toward their original 
or at-rest positions in guide blocks 63 thereby to eliminate the gripping 
engagement of gripping surfaces 41 on the gripping bars with the periphery 
of other end turns 17. Thereafter, the stripped windings 13 are free to 
fall from their predetermined or mounting positions downwardly on to base 
49 of apparatus 47 generally about cylindric member 53, as best seen in 
FIG. 4. Stripped windings 13 usually break apart upon falling onto base 
49, and the operator may sweep them through a disposal opening 69, shown 
in FIG. 1, in the base for collection exteriorly of the apparatus. Of 
course, if other end turns 17 are laced or otherwise interconnected, as is 
well-known in the art, it may be necessary for the operator to lift the 
stripped windings 13 upwardly over arbor 19 after the stripped stator 11 
is disassembled and removed therefrom. 
Another stator 11 may be loaded onto arbor 19 in its displaced position or 
the arbor may be returned by air motor 45 to its mounting position before 
the other stator is loaded thereon for a subsequent cycle or winding 
stripping operation of apparatus 47. 
From the foregoing, it is now apparent that novel methods are provided for 
stripping windings 13 from stator 11 meeting the objects and advantageous 
features therefor set forth hereinabove, as well as other, and that 
modifications as to the precise steps of the methods and the order of such 
steps may be made by those having ordinary skill in the art without 
departing from the spirit of the invention and scope thereof as set out by 
the claims which follow.