US3694887A

US3694887A - Wedgemaker

Info

Publication number: US3694887A
Application number: US85355A
Authority: US
Inventors: Robert G Walker; Donald E Hill
Original assignee: IND PRODUCTS Inc
Current assignee: Advanced Machine and Tool Corp; IND PRODUCTS Inc
Priority date: 1970-10-30
Filing date: 1970-10-30
Publication date: 1972-10-03
Anticipated expiration: 1989-10-03
Also published as: DE2150673B2; DE2150673A1

Abstract

An improved method and apparatus for making insulating wedges for use in an automatic coil placing machine which first severs the wedge material and then contemporaneously forms and slits the wedge is disclosed. The machine is adapted to provide wedges of at least two different lengths and to slit only the longer wedges. The improvement comprises a power operated punch, a forming die, and a plurality of cutting surfaces some of which are retractable wherein the punch forces the wedge blanks through the forming die and past the cutting surfaces in a single stroke.

Description

United States Patent Walker et al.

[451 Oct. 3, 1972 [54] WEDGEMAKER [72] Inventors: Robert G. Walker, Brighton, Mich.;

Donald E. Hill, Ft. Wayne, Ind

[73] Assignee: Industra Products Inc., Fort Wayne,

Ind.

[22] Filed: Oct. 30, 1970 [21] Appl. No.: 85,355

[52] US. Cl. ..29/205 E, 29/596 [51] Int. Cl. ..H02k 15/00 [5 8] Field of Search ..29/205 E, 203 D, 205 D, 596

[56] v References Cited UNITED STATES PATENTS 3,519,862 7/1970 Walker ..3l0/2l4 Primary Examiner-Thomas H. Eager Att0rney-Jeffers and Rickert [5 7] ABSTRACT 9 Claims, 5 Drawing Figures Pmmmm m2 3,694.88! SHEET 2 0F 2 INVENTORS DONALD E. HILL ROBERT G. WALKER ATTORNEYS WEDGEMAKER CROSS REFERENCE TO RELATED APPLICATIONS ing the Same. The present invention is intimately related to and used in conjunction with the copending application entitled Feed Mechanism Overload Release filed Aug. 6, 1970, Ser. No. 61,681 in the name of Robert G. Walker.

BACKGROUND OF THE INVENTION The present invention is concerned very broadly with the automatic manufacture of dynamoelectric machinery and more especially with the forming and inserting of prewound coils and strips of insulating material in the magnetic members of such machines. Specifically, the present invention is concerned with the portion of a machine for such automatic fabrication which makes the insulating wedges for the stator.

One type of insulating wedge which may be manufactured according to the teachings of the present invention is illustrated in FIG. 2 of the aforementioned U.S. Pat. No. 3,519,862 U.S. Pat. No. and FIGS. 4, 5a and 5b of that application illustrate one machine capable of manufacturing such wedges. The actual production techniques relied upon prior to the present invention for manufacturing this type of wedge consisted of a reel which contained a long strip of the insulating material such as mylar being fed first to a V-shape slitting die which when actuated slit the front end of one insulating wedge and the back end of the preceding wedge all prior to the time that the wedge strip was severed into individual wedges. This V-shape die was a good distance removed from the severing die which resulted in substantial problems of synchronizing the severing die so that it parted the mylar at the appropriate point. The prior art process also required rather sophisticated programming when it was desired to supply some wedges having slits and some (generally shorter) wedges without these slits. The prior art V-shape slitting die was actually mounted prior to the wedge maker feeding mechanism and any slippage in the feeding mechanism of course resulted in defective wedges.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide an improved wedge maker.

The primary object of the present invention is achieved by providing the structure which slits the wedges in a position subsequent to the insulating material feed mechanism. By providing this notching mechanism subsequent to the feed mechanism any slippage in the feed mechanism results in only one defective wedge rather than a series of defective wedges. This change in the sequence of operations also results in a materially simplified routine when it is desired to provide both slit and unslit wedges.

Accordingly, it is another object of the present invention to provide a wedge making machine which can automatically produce both slit and unslit wedges and/or wedges of varying lengths in one processing sequence.

According to the teachings of the present invention the wedge is formed and slit in one operation. This is achieved by providing a power operated punch, a forming die, and a plurality of cutting surfaces wherein the punch forces the wedge blanks through the forming die and past the cutting surfaces in a single stroke.

It is therefore a further object of the present invention to provide a simplified wedge maker.

It is yet another object of the present invention to provide a wedge maker of less initial cost and diminished maintenance expense.

These and other objects and advantages of the present invention will appear more clearly from the following detailed disclosure read in conjunction with the accompanying drawing in which:

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a slit phase insulation wedge;

FIG. 2 is a perspective view of a bore slot wedge;

FIG. 3 is a plan view of a portion of a motor stator illustrating the relative placement of the several insulating wedges;

FIG. 4 is a side view of the wedge maker of the present invention showing the insulation feed mechanism; and

FIG. 5 is a portion of the cross sectional view along the line 5-5 of FIG. 4 showing the punch, forming die and cutting surfaces of the wedge maker.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1 and 2 illustrate insulating wedges manufactured according to the teachings of the present invention and FIG. 3 illustrates a partial cross sectional view of an electric motor stator illustrating how those wedges might be positioned within that stator. The wedge 11 of FIG. 1 is a relatively long phase insulation wedge and might for example be used to separate the main winding 13 from the phase winding 15 of FIG. 3. This wedge is cut from a flat strip of mylar" or other insulating material and provided with two pairs of

slits

17a, 17b and 18a, 18b the slits of each of said pairs extending inwardly from opposite edges of the strip toward each other. The entire wedge is bent in a U- shape along its length and when in position in a stator the tabs formed at the ends of the wedge due to the resilient nature of the insulating material tend to depart from the U-shape given them during the forming process and return somewhat to their original flat position thus preventing the wedge from sliding axially in the stator slot. This would be extremely important if for example the main winding 13 were first inserted in the stator, then the phase insulating wedge 11 was inserted and then the phase winding 15 was inserted in the stator. This last step of insertion often causes prior art wedges to be moved axially within the stator sufficiently far that they no longer perform their intended insulating function. The tabs formed by the slitting process are not necessary on the shorter bore slot insulating wedge 19 illustrated in FIG. 2 since-the insertion of this wedge is usually the last step in the fabrication process. It should be noted that the bore wedge 19 is of approximately the same length as the stator being assembled while the phase insulation wedge 11 is sufficiently longer than the stator to allow the end tabs to extend beyond the ends of the stator and perform their intended holding function.

The stator when presented to the machine of the present invention may already have cuffed stator slot wedges 21 in place in the stator slots or these slots may have an insulating coating such as an epoxy resin applied to them. A coil placing machine would then normally insert the winding 13 along with the phase insulation wedge 11 and then the stator would be removed from the coil placing machine and placed on a so-called drift press which serves to push the winding 13 along with the phase insulation wedge 11 outward radially in the stator to make room for the insertion of additional coils. This drifting process also has a tendency to shift the wedge 11 axially but again this is prevented by the tabs at the ends of the wedge which were formed by the slitting process. The stator would then be returned to the coil placing machine for the insertion of the coil winding 15 and the bore slot wedge 19. If more than two windings were desired, this process might be repeated several times with each of the intermediate phase insulation wedges being configured as shown in FIG. 1 and with the last bore slot wedge having the configuration of FIG. 2. Thus, cuffed stator slot wedges if present are slightly longer than the axial length of the stator to allow the cuff portion to extend outside and prevent the inadvertent dislodgement of this wedge, the phase insulation wedges 1 1 are sufficiently longer than the cuffed stator slot wedges to allow the tabs formed by the slitting process to extend outwardly and over the cuff at either end of the stator and the bore slot wedges 19 are approximately the same length as the stator though they might be slightly longer in certain applicatrons.

From the discussion so far, it can be seen that the coil placing machine which inserts the coil 13 in the stator also forms and inserts the phase insulation wedge 11 in a single pass through the stator. This same machine can of course be used to insert the coil 15 and its associated insulating wedge however, since this last wedge is a shorter unslit wedge, the portion of the coil placing machine which fabricates these wedges must be modified between the pass which inserts the coil 13 and the pass which inserts the coil 15. This modification is the very heart of the present invention.

Turning now to FIG. 4 a primary source of power drives the gear 23 which is provided with an off center pin not shown which slides in a slot in the lever arm 25. This lever arm 25 pivots at the point 27 and transmits motion along the connecting link 29 to a second lever arm 31. The connecting link 29 forms the subject matter of the earlier mentioned Feed Mechanism Overload Release application Ser. No. 61,681. The second lever arm 31 is pivoted at point 33 and thus by way of a second connecting link 35 imparts a back and forth linear motion to the sliding block 37. This block 37 carries a pawl like member 39 which alternately grips and releases the insulating material between the pawl 39 and material support 40 so as to feed the material in increments of a length determined by the control signals imparted to the hydraulic cylinder 41. This cylinder 41 is actuated by accurately metered quantities of hydraulic fluid or air supplied by way of tube 43 which serve to extend or retract the rod 45 and thus vary the distance between the connecting link pivot point 47 and the lever arm pivot point 27. Varying the distance between these two points of course varies the extreme travel for the sliding block 37 and thus varies the length of insulating material fed per cycle.

The insulating material is fed from a roll of stock material or other source and passes under an idler roller 46 and into the feed mechanism. The feed mechanism may have a second spring loaded feed pawl 42 to prevent the retracting of the material. The insulating material is fed through the feed mechanism along a passage way 49 and past the cutter 51. The cutter 51 is actuated once for each revolution of the geared wheel 23 and thus each time the feed mechanism goes through one cycle the cutter cuts off a wedge blank having a length equal to the extreme travel of the sliding block 37. As will be noted subsequently this cutting operation sometimes causes the severed wedge blank to move varying distances in its passageway and since its positioning subsequent to the cutting operation is critical some means must be provided for holding the wedge blank in a definite position as the cutting operation occurs. The evolution of the insulating material after being severed into wedge blanks of prescribed lengths is best seen in reference to FIG. 5.

At the time the insulating material is severed into a wedge blank, it is in the position illustrated by dotted lines at 53 of FIG. 5. The punch 55 is retracted from and above the unforrned wedge blank 53 at this time but soon thereafter begins its downward travel and its motion in conjunction with the edges of the forming die 57 fold this previously flat wedge blank into a U-shape. Directly below the forming die 57 is located a plurality of cutting surfaces 59 which in conjunction with the downward motion of the punch 55 cut the insulating material to provide the slits 17 and 18 of FIG. 1. After slitting, the punch continues its downward motion and deposits the formed and slit insulating wedge in a notch 61 on a cylinder. At this point, the punch 55 retracts to a position above 53 to allow a new wedge blank to be inserted and formed, the cylinder is indexed by link of FIG. 4, new material is fed and the punch forms, slits and deposits another wedge in a new slot. The axial length of the cylinder exceeds the length of the longest of the insulating wedges to be fabricated and accordingly the sides of the notches 61 hold both the main portions of the wedge and the tabs formed by the slitting operation at the same position for insertion in the stator. When the cylinder has the appropriate notches filled with wedges, all wedges are axially pushed from the cylinder into a stator along with a coil being inserted by the coil placing machine.

As noted earlier, the operation of severing the insulating material into wedge blanks of the desired length of the cutter 51 would often cause the severed wedge blank to jump forward by varying amounts. To overcome this problem, the punch 55 is provided with a piano wire spring 63 which rides the surface of the insulating material when it is in its position 53 and the punch is in its completely retracted location. The additional friction caused on the wedge blank by this spring either eliminates the jumping or at least limits these jumps to controlled and consistent amounts so that the slits 1'7 and 18 are properly located relative to the wedge blank.

There are of course, a pair of cutting surfaces 59 to cut for example the pair of

slits

17a and 17b of FIG. 1 and a second pair of cutting surfaces either directly behind or directly in front of this pair of cutting surfaces 59 to provide the

slits

18a and 18b in the wedge of FIG. 1. One such pair of cutting surfaces is provided with connecting links 65 which when actuated by an air or hydraulic cylinder 67 of FIG. 4 serve to pull the cutting surfaces away from the wedge being formed so that that wedge is not slit by the cutting surfaces 59. As was noted earlier, it is desirable in the fabrication of stators to provide a long slit wedge as illustrated in FIG. 1 and a shorter unslit wedge as illustrated in FIG. 2. The present invention thus need only retract the one pair of cutting edges since the shorter wedge does not extend sufiiciently far beyond the cutter 51 to be slit during its forming process by the unretracted pair of cutter blades. It is of course within the scope of the present invention to also retract the second pair of cutting edges if longer unslit wedges were desired. The punch forming die and cutters illustrated in FIG. 5 form and slit the wedge in a single cycle of the punch and while the forming and cutting is not simultaneous it would be made so by fashioning the forming dies 57 with narrow slits which would accept the cutting surfaces 59. When this forming and cutting or slitting occurs either simultaneously or sequentially during one cycle of the punch 55, the forming and slitting are said to be performed contemporaneously.

The present invention then provides for a means for feeding the wedge material in increments of first, second and perhaps third and fourth lengths depending upon the position of the air cylinder 41 which in turn defines the lever arm length of the feeding mechanism. The wedge material is severed into wedge blanks of a length determined by that air cylinder position by the cutters 51a and 51b and these wedge blanks are then contemporaneously formed and slit by the operation of the power operated punch 55, the forming die 57 and the plurality of cutting surfaces 59. The pairs of cutting surfaces are so positioned that when the air cylinder is retracted and shorter wedges are being fed and cut, the shorter wedges do not extend sufiiciently far along their path of travel to be slit by one of the pairs of cutting surfaces and the other pair of cutting surfaces is provided with a disabling means to disable the cutting function of the second pair by retracting them. The scheme provides longer slit wedges for phase insulation purposes and shorter unslit wedges for bore slot wedges as the last step in fabricating the stator. One or both of the cutting surfaces may be provided with an adjustment means 69 which will allow the machine to be adjusted to slit insulating material throughout a range of desired length depending upon the configuration of the particular stator being assembled.

Numerous other modifications will suggest themselves to those of ordinary skill in the art and accordingly the scope of the present invention is to be measured only by that of the appended claims.

Iclaim:

1. In an automatic coil placing machine, an improved wedge maker comprising:

means for feeding wedge material in increments of a first length; means for severing the wedge material into wedge blank s of said first length; means or contemporaneously forming and slitting the wedge blanks; and means for inserting the thus formed and slit wedges into a stator.

2. The improvement of claim 1 further comprising means for modifying the feed means whereby wedge material may be fed in increments of a second length.

3. The improvement of claim 2 further comprising means for at least partially disabling said forming and slitting means whereby material fed in increments of said second length may be formed without slitting.

4. The improvement of claim 1 wherein said forming and slitting means comprises:

a power operated punch, a forming die, and a plurality of cutting surfaces;

said punch forcing wedge blanks through said forming die and past said cutting surfaces in a single stroke.

5. The improvement of claim 4 wherein said plurality is four and further comprising means for selectively retracting two of said four cutting surfaces.

6. The improvement of claim 5 further means for selectively modifying the feed means whereby wedge material may be fed in increments of a second length and wherein said means for retracting is activated for wedges of the shorter of the two said lengths whereby said shorter wedges are formed without slitting.

7. The method of providing a plurality of wedges of each of at least two lengths of insulating material for the slots of a stator comprising:

feeding the insulating material from a roll of stock material; selectively cutting the thus fed material to provide wedge blanks of at least two different lengths;

selectively contemporaneously forming a longer wedge into a U-shape and laterally slitting that wedge, and selectively forming a shorter wedge into a U-shape without laterally slitting that wedge whereby both slit and unslit wedges may be produced.

8. A machine for providing two pairs of slits in a strip of insulating material, the two slits of each of said pairs extending inwardly from opposite edges of the strip of insulating material toward each other comprising:

a power operated punch, a forming die, and a plurality of fixed cutting surfaces;

said punch forcing said insulating material through said forming die and past said cutting surfaces in a single stroke.

9. The machine of claim 8 further comprising a pair of retractable cutting surfaces, said plurality of fixed cutting surfaces positioned to provide one of said pairs of slits and said pair of retractable cutting surfaces positioned to provide the other of said pairs of slits.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 s Dated October 3, 1972 I t Robert G. Walker and Donald E. Hill It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

lines 27 and "U.S .Pat.No. second occurrence,

should be deleted.-

Col. 3, line 25, "the" omitted between "Thus" and "cuffed" Col. 6, line 28 (Claim 6) "comprising" omitted between "further" and "means" Signed and sealed this 20th day of February 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Claims

1. In an automatic coil placing machine, an improved wedge maker comprising: means for feeding wedge material in increments of a first length; means for severing the wedge material into wedge blanks of said first length; means for contemporaneously forming and slitting the wedge blanks; and means for inserting the thus formed and slit wedges into a stator.

4. The improvement of claim 1 wherein said forming and slitting means comprises: a power operated punch, a forming die, and a plurality of cutting surfaces; said punch forcing wedge blanks through said forming die and past said cutting surfaces in a single stroke.

7. The method of providing a plurality of wedges of each of at least two lengths of insulating material for the slots of a stator comprising: feeding the insulating material from a roll of stock material; selectively cutting the thus fed material to provide wedge blanks of at least two different lengths; selectively contemporaneously forming a longer wedge into a U-shape and laterally slitting that wedge, and selectively forming a shorter wedge into a U-shape without laterally slitting that wedge whereby both slit and unslit wedges may be produced.

8. A machine for providing two pairs of slits in a strip of insulating material, the two slits of each of said pairs extending inwardly from opposite edges of the strip of insulating material toward each other comprising: a power operated punch, a forming die, and a plurality of fixed cutting surfaces; said punch forcing said insulating material through said forming die and past said cutting surfaces in a single stroke.