US2942511A - Apparatus and method for making laminated ferromagnetic cores - Google Patents

Description

June 28, 1960 J. J. MOYNIHAN APPARATUS AND METHOD FOR MAKING LAMINATED FERROMAGNETIC CORES 5 Sheets-Sheet 1 Filed Aug. 4, 1953 1N VEN TOR. L/. ay/24M June 28, 1960 J. J. MOYNIHAN APPARATUS AND METHOD FOR MAKING LAMINATED FERROMAGNE'I'IC comas 3 Sheets-Sheet 2 Filed Aug. 4. 1953 IN VEN TOR. J/z/z/ flgaymm June 28, 1960 J. J. MOYNIHAN 2,942,511

APPARATUS AND METHOD FOR MAKING LAMINATED FERROMAGNETIC CORES Filed Aug. 4, 1953 '5 Sheets-Sheet 3 34.9 2 0 I3 Coflfro/ Coalol Confr'a Control 5; g l Llewcel I flev/ce [Dev/cg] Del/lee 303 3/5 5 Z56 1-268 492 9 Z49\ @341 62? 34a 56m INVENTORY/33 United States Patent APPARATUS AND METHOD FOR MAKING LAMI- V NATED FERROMAGNETIC CORES John J. Moynihan, Chicago, Ill., assignor to M 8; F Associates, St. Joseph, Mich., a limited partnership Filed Aug. 4, 1953, Ser. No. 372,363

17 Claims. (CI. 83-29) This invention is concerned with an apparatus for and a method of makinglaminated ferromagnetic cores for small transformers, magnets, and'the like.

Ferromagnetic cores for small transformers and the like operating at power and audio frequencies generally are made by stamping laminations from sheet steel and stacking them together. The cores are E-shaped with an I bar lying across the ends of the legs of the E and parallel to the back so that the resulting core is symmetrical. To conserve material in manufacture, the E-shaped laminations are blanked out in confronting pairs with the ends of their legs contacting one another. The material stamped out to form the windows in the core thus serves as the laminations forming the I bar of each core, and no material is wasted except for that stamped out to form holes for guides in a punch press and often later serving as bolt holes for holding the laminations together or for mounting the magnets. The laminations so produced are generally known as scrap-less E and I laminations.

Heretofore all of the lam-inations going into one magnet core generally have been identical. so that the central leg of the E-shaped core generally has been square in cross section, While the other two legs, the back, and the I bar generally have had a rectangular cross section equal to one half the cross section of the central leg. This maintains the flux density, and hence the core losses uniform throughout the core.

As fully set forth in my copending application Serial No. 372,213,. filed of even date herewith and entitled Ferromagnetic Core, I propose the provision of a ferromagnetic core for small transformers and the like made up of stacked E and I laminations wherein the central leg of the core is cylindrical. The provision of a cylindrical center core leg results in substantial savings in copper and iron.

The provision of av cylindrical. core leg. permits the use of a cylindrical. coil winding. Due. to its contour or shaping, a round coil turn is about 9% shorter than a square coil turn embracing the same cross sectional core area. Thus the round coil turn requires 9% less, by weight, of copper; and inasmuch as resistance varies directly with length, each round coil turn has approximately 7 9% less resistance than an equivalent square coil turn. A cylindrical coil thus has approximately 9% less resistance than an equivalent rectangular. coil. If it is desired only to'maintain the coil resistance withincertain maximum limits, to thereby limit power and heat losses, advantage may be taken of the foregoing, in my invention as set forth in the aforesaid copending application, to reduce the wire size, thereby to effect a further saving, by weight, in the copper required. A reduction in wire size of one half size or gage increases the resistance, for any given length, approximately 12%. Considering that with my invention a coil length of 9% less is employed there would result, with a decrease in wire size of one half size or gage, an apparent or anticipated increase in resistance of approximately 3%.

However, the use of smaller wire permits more turns 2,942,511 Pate ted une 28, 1 6

ice

2 per layer in the coil. This leads to fewer and thinner layers. The fewer and thinner layers reduces the mean diameter of the coil so that for a given total number of turns (as compared with conventional practice) 1s over-all length of wire is required, resulting in a resistance decrease due to this factor of approximately 3%; so that the'final resistance. value of the completed or corn posite coil will be approximately the same-as inhe. conventional construction. foregoing factors referred to, including the "permissible use of smaller wire, and the decreased length thereof for equivalent performance, results in a savin's'of copper by weight, as compared with a conventional coil, of approximately 26%.

The smaller physical size of the coil when wound in a cylindrical configuration is accompaniedby shorter-magnetic paths allowing a reduction in the amount of steel necessary to construct a core.

An object of this invention is 'to'provide means for and a method of producing a laminated ferromagnetic core having a cylindrical center leg. 7

As fully pointed out in my aforesaid pendingapplication, the windows in succeeding laminations must be relatively shifted toward and away from one another in order to form the cylindrical center leg. More specifically, the windows are farthest apart in the center of "a stack of' laminatio-ns making up a core, and move progressively closer together in succeeding laminations moving out toward the top and bottom of the stack. In order to form a substantially circularcylindrical'jcore, rather than an elliptical or other non-circular core, it'is necessary that the windows move relatively toward and away from one another in accordance with the thickness of the l-aminations. center lamiuationout toward the top and bottom of a core stack, the window of each succeeding lamination must move closer together a distance commensurate with the thickness of. the lamination and its position'in the stack. The shifting distance cannot be exactly predetermined, as stock thickness may vary. More particularly, I prefer to make core laminations from strip stock, and. the thickness of a strip may vary from end to end of the strip.

and a method of automatically forming windows'in dif ferent locations in different laminations so that the stacked laminations will produce a circular center 'leg.

More specifically, it is an object of this invention :to provide means and methods for automatically shifting the window position in different laminations in accordance with the stock thickness.

At the'center of a core stack, a lamination lies substantially along a diameter. The window space for admitting the coil winding therefore can be ata minimum. Each a minimum of the ferromagnetic stock, I use a novel J modification of the scrapless E and I laminations, the I being equal in width to the minimum window width.

' Additional material must be removed, from certain other laminations to provide the wider windows.

It therefore is an object of this invention to provide means and methods for progressively removing additional metal from the E laminations to provide wider windows in accordance with a predetermined pattern.

Over all, the combination of the More specifically, in working from the I An object of this inventionis to provide apparatus for V 7 Amore'specific object of this invention is to remove additional material from the E-shaped laminations to provide progressively wider windows in accordance with the stock thickness.

' Other and further objects and advantages of the present invention will be apparent from the following description when taken in connection with the accompanying drawings wherein:

Fig. 1 is a side view, somewhat schematic in nature, of a punch press constructed and operated in accordance with the principles of my invention;

Fig. 2 is a perspective view. of the punching layout;

-Fig. 3 is a perspective view showing a part of the stacking chute;

Fig. 4 is a side view of the mechanism for relatively shifting the stock and dies in accordance with the stock thickness; i

Fig. 5 is a horizontal sectional view taken along the line 5-5 of Fig. 4;

Fig. 6 is a horizontal view partially in section taken along the line 6-6 of Fig. 4 and showing the shifting cam;

Fig. 7 is an enlarged, detail view of a portion of Fig. 4;

Fig. 8 is a perspective view illustrating a modified arrangemeut of the apparatus;

Fig. 9 is a plan view of a punching arrangement accompanying the apparatus of Fig. 8;

Fig. 10 is a view taken in section along the line 10-10 of Fig. 11 illustrating the core produced; and

Fig. 11 isa sectional view taken along the line-ll-ll of Fig. 10.

Referring now in greater particularity to the figures, andfirst to Fig. 1, it will be seen that my invention incorporates a punch press 20. The punch press-is shown somewhat schematically since it may be of a conventional type. A standard O.B.I. (open back inclined) type press may be used, but I prefer to use the type known commercially as a Henry and Wright due to the more accurate alignment of punches and dies.

The punch press includes the usual base 22 and a motor 24 driving the head 26 mounted on the connecting rods 28 by means of a belt 30 passing over a pulley wheel 32 on the motor shaft and over a pulley wheel 34 on a drive shaft 36. The drive shaft 36 carries a suitable weighted flywheel, and is connected through suitable gearing to the connecting rods 28. A die block 38 is mounted on the bolster or table 40 carried by the base 22, and suit-- able punches are carried by a block 42 on the head 26.

Ferromagnetic stock in the form of a strip 44 is fed from a roll 46 between a set of idler support rollers 48 and a pair of pressure, feed rollers 50 over the die block 38. The rollers 50 are driven from the motor 24 by any suitable means such as a belt 51 and pulley arrangement in timed relation to the operation of the punch press. In order to perform the multiplicity of punching operatlons necessary I provide a multiplicity of punches and cooperating dies past which the strip is fed. The punches and dies may be arranged in a straight line and the strip may be fed straight past them. This takes a rather large punch press, however, and I prefer to arrange the punches and dies side by side as the physical space requirements are thereby reduced and a smaller punch press can be used. In order to feed the strip stock successively past the laterally arranged punches and dies, I loop the stock over the top of the machine several times as illustrated at 52 so that the stock is fed between the rollers 50 and through the punch press 20 several times. Channelshaped guides 54 are supported above the head 26 by suitable supporting brackets 56 secured to the table 40. The stamped laminations are fed in stacked arrangement from the punch press by a stacking chute 59 supported by any suitable supporting structure (not shown).

In Fig. 2 the strip 44 is shown as it is fed the multiplicity of times between the rollers 50 and over the die block 38, the lowermost roller 50 and the punch press having been omitted for clarity of illustration. The punches are shown only in part and it will be understood that they are afhxed in any known or suitable manner to the block 42 mounted on the head 26.

On the first pass of the strip through the punch press, as illustrated at 58, a pair of cylindrical perforating dies 60 punches apertures 62 in the strip for guide purposes. Pilots 64, having rounded noses, enter the apertures 62 properly to locate the portion 58 of the strip 44 after the holes 62 have been punched therein, suitable apertures being provided in the die block 38 for cooperation with the punches 60 and the pilots 64. On the second pass or loop 66 of the strip, 44 through the punch press, a rectangular punch 68 and cooperating aperture in the die block 38 shear a rectangular section from the strip to form a rectangular aperture 70. The rectangular section forms the I bar of a core and may drop into a receptacle beneath the punch press, or preferably is fed from the punch press through a stacking chute similar to the chute 59 which is used for stacking the E-laminations as they are produced. The loop 66 is guided laterally by pairs of depending guide members 72 and 74 engaging the edges of the strip adjacent the edges of the die block 38. The depending guide members 72 and 74 are carried at the end of a U-shaped member 76 having a connecting rod 78 extending into a control unit 80. The control unit 80 as will be hereinafter pointed out includes suitable mechanism for longitudinally shifting the connecting rod 78 and thereby laterally shifting the strip portion 66 by means of the depending guide members 72, 74. The distance the strip is shifted is in accordance with a predetermined pattern and with the thickness of the strip as will be apparent.

On the next pass or loop of the strip 44 through the punch press, this portion, of the strip being indicated at 82, a second rectangular punch 84 shears a rectangular section from the strip toprovide a rectangular aperture 86 parallel to each rectangular aperture 70. The apertures 86 are coextensive with the apertures 70 and are spaced equidistant from the center line of the strip. The lateral position of the strip portion 82 is controlled by pairs of depending guide or positioning members 88 and 90 similar to the members 72 and 74. The members 88 and 90 are carried adjacent the ends of a U-shaped member 92 having a connecting rod 94 extending into a control apparatus or mechanism 96 similar to the control 80, but shifting the strip in the opposite direction.

On the succeeding pass or loop through the punch press, this portion of thestrip being identified by the numeral 98, the outer edges of the apertures 70 may or may not be shaved according to the intended position in the finished core of the lamination being produced. In the illustrative embodiment of Fig. 2 the outer edge is shown as being shaved by a rectangular punch 100, and it will be understood that the amount of metal removed by this die will vary from one point to another in the strip according to a predetermined pattern.

The lateral position of the strip portion 98 is determined by pairs of depending guide members 102 and 104 similar to those heretofore disclosed and carried at the ends of a U-shaped member 106, conveniently arranged on the opposite side of the punch press from the members heretofore shown and described, although it will be understood that it can be arranged on either side. A connecting rod 108 connects the U-shaped member 106 to a control device 110 similarto the controls 80 and 96 previously referred to.

On the fifthloop or pass of the strip 44 through the punch press, this portion of the strip being identified with the numeral 112, the apertures 86 may be shaved or enlarged similarly to the apertures 70 in the previous por tion. The rectangular punch 114 is shown as shaving or enlarging the outer edge of the rectangular apertures 86 to the same size as the apertures 70, the shaved apertures 70 and 86 beingsymmetric about the central axis of the strip. The lateral position of the strip portion 112 is controlled by pairs of depending guide members 116 and 118 on the ends of a U-shaped member 120. A connecting rod 122 connects the member 120 me control device 124 similar to those heretofore shown and described.

On the final pass or loop of the strip 44 through the punch press, a rectangular punch 126 parts the strip at 128*and 130 to cut off the end of the strip into a pair of similar E-shaped laminations. The punch 126 punches certain of the E-shaped laminations 1'32 through the die block into a stacking chute, while the remaining E-shaped laminations 134 fall from the edge of the die block into a suitable receptacle, or preferably into another stacking chute.

It will be understood that the strip4'4 is fed stepwise through the punch press 20 so that the strip is stationary each time that the head 26 descends. To this end, the belt 51 and pulley mechanism for driving the feed rollers 50 incorporates an intermittent motion mechanism (not shown) of suitable or conventional type such as a Geneva mechanism. Suitable pilots 136 are provided on the block 42 carried by the head for cooperation with the apertures 62 'of the strip 44 in its last loop or pass through the punch press in order to position the strip properly for cutting off of the E-shaped laminations by the punch 126. Other pilots may be provided on the head block for longitudinal positioning of the strip in its intermediate loops; These pilots must be narrow relative to the holes 62 to cooperate with the holes as the strip is shifted laterally, or must be shiftable laterally with the strip. Such pilots have been omitted from the drawings for clarity of illustration.

The stacking chute 59' for the E-shaped laminations 132 is shown in perspective in Fig. 3. The stacking chute 59 extends from beneath the die block in acontinuous curve138 as illustrated in Fig. 1 and exits through an aperture 140 (Fig. 3) in the side of the punch press 20. The stacking chute through the curved portion thereof comprises four longitudinal struts 142 joined together by rectangular braces 144. The braces hold the struts a proper distance apart to allow the E-shaped laminations to slide therethrough broadside. The abutting of adjacent laminations against one another keeps them from tipping over. After leaving the curved portion 138 the stacking chute is provided with a straight inclined section 146 curving into a substantially horizontal section 148. The lower two of the longitudinal struts 142 are continued through the sections 146 and 148. The upper pair of the struts 142 is terminated and a pair of longitudinal struts 150 at an intermediate height is joined to the continued struts 142 by U-shaped connectors or brace members 152. The stacking chute is supported inside the punch press and outside thereof by any suitable means (not shown). The laminations in the stacking chute being free to move relative to one another to a limited extent act very much the same as water in a tube. The weight of newly sheared laminations pushes on the laminations already in the chute and feeds the laminations down through they chute alongthe curved portion 138 and then upwardly inthe inclined straight section 146 and to some distance from the punch press where they readily can be removed for assembly into individual ferromagnetic cores. This action of the laminations in the chute makes it unnecessary for the punch 126 to push the laminations through the chute. Such pushing on the part of the punchwould place undue reactive forces on the punch and on the head and would dull the punch.

It will be understood that a similar stacking chute may be used for feeding the E-shaped laminations 134, and a slightly modified stacking chute may be used for feeding the rectangular laminations stamped out by the punches 68- and 84. Such chutes have been omitted from the drawings to maintain the greatest possible clarity in the drawings.

The mechanism for laterally shifting the various loops or portions of the strip 44 relative to. the punches is in detail at 186 in Fig. 7.

endless link chains '154 and 156 trained oversprocket wheels 158 and 160 arranged in vertical pairs and rotatably mounted on a pair of suitable brackets 162 depending from the bolster or table 40. a T

The sprocket chain 154 carries a plurality of support members 164 each of which is substantially T-shaped in configuration with the stems of the Ts connected to alternate links. The heads of the T's are provided with shoulders 166 having short tapered surfaces 168 above them and relatively long tapered surfaces 170 beneath them, adjacent supports 164 nearly abutting on the straight reaches of the chains and the surfaces 168 and 170 of adjacent supports forming nearly continuous surfaces.

The opposite chain 156 carries a plurality of positioning members 172 confronting the supportmembers 164, the chains being suitably synchronized by means such as a cross shaft 174 interconnecting bevel gears 1'16 meshing with bevel gears atiixed to the lowermost sprockets 158, 160 for rotation therewith. The positioning mem bers, 172are provided with inclined surfaces 178 parallel to the inclined surfaces 170 of the support members and spaced. therefrom a distance equal to the diameter of a circular slug 180 punched from the strip'44 by the punches 60. Shoulder portions 182 overlie the inclined, surfaces 17 8 and are spaced above the shoulder portions 166 of the support members. Short inclined surfaces 184 above the shoulder portions 182 form substantially continuous surfaces with the inclined surfaces 178 of the adjacent positioning members.

The chains are driven by the slugs 180 as will be brought out more fully hereinafter and act through suitable connections suchas bevel gears 186 and a drive shaft 188 to drive a torque amplifier 190. The torque amplifier may be of any type known in the art and requires a. very low input torque for driving an output shaft '192 in synchronism with the input shaft 188. The output shaft 192 controls one or more of the various control. devices80,

96, 110, and 124 by any suitable means. such as a earn 194 mounted on the end of the drive shaft 192 and having a cam track 196 receiving a. cam follower 198. The cam: follower 198 may be connected directly to one of the connecting rods 78, 94, 108, 122 to move theserods as indicated by the double ended arrows, for example, the connecting rod 78 as shown 'in Fig. 4. All of the. control devices are operated in accordance with the movement of the chains 154 and 156 and to this end may include followers similar to the follower 198 engaging with cams similar to the cams 194, all of the cams being driven in synchronism byany suitable or conventional means such as gearing and shafting. The gearing and shafting have been omitted from the drawings as this or any equivalent structure may be conventional and would tend to confuse the drawings without adding anything useful to the disclosure.

The strip 44, and, consequently the slugs 189 stamped therefrom, arequite thin, and whenthe thickness of the. strip varies, the increment is exceedingly smalle Impractically precise measurements Wouldbe necessaryto control the lateral shifting of this-strip if the strip were shifted directly in accordance with the variations of thickness in the strip. The mechanism disclosed in Figs. 4-7

and heretofore described rnultiplies'the incremental varia tions. Theslugs 180. rest at some point along the vertical reaches of the chains 154 and 156 on the shoulder 166. of one of the support members 164. This is illustrated If the strip thickness happens to be of a particular value. some of the slugs will rest directly on the shoulder 166 of the support member 164 directly above the one providing the support illustrated" at 186. In general, however, the thickness Will be such that the top of one of the slugs will not be substantiallycoplanar with the shoulder 166 of the next higher sup port member, and the next higher support-member therefore will serve only to position the slugs. A disjoined column of slugs equal in height to several supportv menr-i,

hers therefore will be'supported atthe position indicated at 186. The'vertical reaches of the chains are made sufiiciently long that somewhere the top surface of a slug will come out coplanar with one of the shoulders166 so that that shoulder 166 also will support a column of slugs. This coplanar alignment is somewhat along the same lines as a vernier wherein different units of length line up every so often.

The slugs 180 pass through an aperture in the table or bolster 40 and are supported in a column by suitable side guides 200 .(Fig. .5) supported by spacers 202 mounted on the brackets 162. Theside guides 200 support the column laterally throughout its length, and back-up members 204 are provided behind the chains 154 and 156 along" the vertical reaches thereof to assure linearity of the reaches. '.As 'each slug is stamped from the ship it advances the sprocket chains 154 and 156 a distance in accordance with the thickness of the slug. Since the Vernier-like action of the slugs and support members causes a large number of slugs to be supported as a continuous column, it is the total thickness of a large number of slugs that determines the total travel of the sprocket chains, and hence the rotation of the cam 194. The cam 194 (and similar cams in all of the control devices) are formed so as to shift the strip portions laterally in accordance with a predetermined pattern so as to produce a round core leg. The movement of the chains in accordance with the thickness of the slugs engrafts upon this predetermined pattern a function of the thickness of the strip so that the strip portions are shifted laterally in accordance both with the predetermined pattern and with the thickness of the strip. A substantially perfect circular cross section of the central leg of the core thus is insured.

The function of the foregoing apparatus possibly will be more fully understood with reference to a transformer or similar core produced thereby. A transformer 206 is shown in Figs. 10 and 11 and includes a plurality of the E-shaped laminations, for instance, the laminations 132, stacked together to form a core 208 in cooperation with a stack of the I bars or laminations 210, the latter being arranged across the ends of the legs of the E. As Will be seen with reference to Fig. 10, the width K of the laminations of the center leg 212 varies from a maximum at the center of the stack to a minimum at the top and bottom of the stack so as to provide a central leg which is substantially circular in cross section. At the same time the width I of the end legs 214 varies from a minimum at the center to a maximum at the top and bottom of the stack. The window width G is non-uniform due to the fact that the lamination at the center of the core lies along a diameter of the coil while the remaining laminations are chordal relative to the coil. Accordingly, the window width G varies from a minimum at the center of the core stack to a maximum at top and bottom! The coil 216 readily will be seen to be round wound or cylindriform in configuration leading to the substantial savings in copper as earlier set forth.

Following the above brief description of the ferromagnetic core, a further'sumrnary of the operation of the invention might prove enlightening. The function of the entire mechanism shown in Fig. 4 is to integrate continuously the thickness of the stock passing through the tools. This integration results in rectilinear motion of the cam follower 198, and hence of the various connecting rods as 78, 94, etc. The return or extent of motion of the cam follower is an arbitrary function of the sum of the thicknesses of the material of the individual scrap pieces punched out by the tools. The function is arbitrary inasmuch as it is dependent on the shape of the cam track, as well as on the integrated thickness.

The necessity for an integrating thickness measuring device to control the rotation of the cam arises from the normal variation in the gage of the stock being used as raw material. For example, #24 gage electrical sheet is .025'thick with a milltoleran'ce on thickness of plusor minus .003". If a stacked core is desired to be one inch in total thickness, and the material is running exactly to gage, there will be forty laminations in the stack. If the material runs light to the limit of the mill tolerance, there will be forty-five laminations in the stack. Conversely, if the material runs maximum heavy, there will be thirty-five laminations in the stack. There is no way of avoiding this mill variation. Thus, if height is relied on as a criterion, the number of laminations in the stack must vary. If the number of laminations is relied on as a criterion, the stack will be of an improper height.

With the height as criterion as is the case throughout this exemplary embodiment of my invention, not only the number but also the planform of the individual laminations must change with the variations in thickness. Therefore, it is impossible to predeterrnine a schedule of positions for the variable tool element based on the number of strokes taken by the press following the inception of a given forming operation or sequence of operations. Such a schedule would, if based on normal gage of material, result in an elliptical cross section of the middle leg of the core. With light gage stock, the major axis of the ellipse would be the diameter of the circle in the normal gage schedule and would be parallel to the surface of the laminations. With heavy gage stock, the minor aXis of the ellipse would be the normal gage diameter and similarly oriented. The thin gage material would be inadequate for the design fiux density, while the thick gage material would not permit slipping the prewound coil over the middle leg.

Members 164 and 172 are so formed, and the total active length of the chain members in engagement with the slugs is so designed, that a relatively large column of slugsis used as an integrating column at any given time, thereby completely avoiding or at least minimizing jumps" in the advance of the shaft 188 due to possible ineommensurability of the gage of the material referred to the pitch of the chain.

As will be'appreciated, the last or upper-most slug in the column tends to control the lateral shifting of the tool relative to the sheet stock. However, if reliance were placed solely on the thickness of an individual punching, measurements would have to be impractically precise. The use of a column of slugs effectively gives a multiplication of slug thickness, thereby avoiding the necessity of impractically extreme precision. Several slugs can be taken in the columns without leading to error, since the thickness of the strip stock varies gradually, not suddenly. The height of the column is not a factor in the motion of the cam or other control elements. However, the height is important in allowing the number of shoulders 166 to be made sufficiently large so that if the pitch of the chains (and shoulders) is incommensurable with the thickness of the slugs, there will be a minimum of lost motion when the support of the column shifts from one shoulder to another. The important thing is that the last slug punched forms the top of a column of uncertam effective height. Thus, the column is always lowered a distance equal to the thickness of the slug forced on to the top of the column.

In the illustrative embodiment of my invention heretofore set forth, the various cooperating punches and dies are laterally disposed relative to one another and the strip is passed through the punch press a plurality of times. The punches and dies are positioned relative to the strip by laterally shifting the strip. The laminations also can be formed by arranging the punch and die sets in a line and thereby passing the strip in a straight line through the punch press. Likewise, the strip and punch and die sets can be relatively located by laterally shifting the punch and die sets while maintaining the strip laterally fixed. Apparatus embodying the principles of my invention in this manner is shown in Figs. 8 and 9. i

The apparatus includes a sub-press 218 comprising a punch holder 220 and a die shoe 222 which'will be mounted on the head and bolster of the punch press as will be understood. Guide rods 224 extendbetween the punch holder and die shoe to insure proper alignment thereof at all times.

At the, entering end of the sub-press 2118 there is provided a supporting block 226. for supporting the strip stock 44a. It will be understood that the strip 44a is fed by means similar to those heretofore described in timed operation with the reciprocation of the punch press and the consequent relative movement of the punch holder and die shoe toward and away from one another. A strip guide 228 is positioned on top of the block 226 and is channel-shaped in configuration to guide the strip laterally. The guide 228 is provided with a pair of apertures .230 in its upper surface providing passage for a pairof cylindrical punches 232 for punching pilot holes 62a in the strip as indicated in Fig. 9. The slugs stamped the, strip to form the apertures 62a are used for controlling the lateral position of the. punches and dies bymeans of an apparatus similar to that shown and described in Figs. 47. The apertures 62:: cooperate with pilots; 233. for properly positioningthe strip throughout the ensuing punching operations as will be apparent hereinafter,

A punch carrier 234 is mounted on the punch holder 7 220 for transverse movement relative thereto by means of a dovetail slide 236 fitting in a dovetail slot 238 in the under side of the-punch holder. The punch carrier 234- carries a sect-angular punch 68 1. A movable die carrier 242 is mounted on the die shoe 222 for movement transversely thereof by means of a dovetail slide 244 on the carrier; 242 and a dovetail guideway (not shown) in the die shoe. The punch carrier 234. and die carrier 242 are joined together for movement transversely of the sub-press 2118 by means of guide Iods 246 fixed in one of thecarriers, for instance the die carrier 242, and reciprocable through an aperture 248 in the other carrier. The punch carrier 234 and die carrier 242 along with the guide rods 246 and the punches and dies carried thereby form a movable sub-press tool 249.

The die carrier 242 carries a die 251') having a rectangular aperture 252 therein aligned with the punch 68a;

for punching rectangular shaped I bars from the, strip 44a. The movable sub-press tool 249' is connected by means such as a connecting rod 254 to a control device 256 such as that shown and described with regard to the previous embodiment of my invention. This control device shifts the sub-press tool 249 transversely of the sub-press in accordance with a predetermined pattern and in accordance with the thickness of the strip stock 444;, The punch 68a forms rectangular apertures 70a in the strip stock 44;: similar to the rectangular apertures formed in the stock in the first embodiment of my invention.

.A second sub-press tool 258 similar in construction to the sub-press tool .249 and having a cooperatiugirectangular punch,8'4a and rectangular die aperture (not shown) isrnounted for movement transversely of the sub-press 218. This mounting is similar to that heretofore described and includes. a dovetail slide 260 on the punch carrier 262 fitting in a dovetail guideway 264, and a dovetail slide (not shown on the-die carrier (not shown) :fitting in a dovetailguideway 266'in the die shoe 222. The sub-.

presstool .258'is controlled in lateral position relative to the strip 44a by a connecting .rod 268 and a control device. 270; similar to those heretofore set-forth. The rectangular punch 84a of .the second sub-press tool .258v

stamps another '1 bar strip and leaves a rectangular aper ture 8 6a which is of the same size as the rectangular aperture 68'a -and is symmetrical about the center line of the strip 44a therewith.

A sub-press tool 272 substantially identical with the tool 249; is mounted in the sub-press 218 adjacent the tool .258, The tool 272 includes a punch carrier 274 mountedby means of a dovetail slide 276 and guideway 2,18, and/a die carrier 280 mountcd by means of a dovetail slide Y282 and guideway (-not shown). The punch carrier 274 carries a rectangular punch a aligned with a rectangular aperture 284 in a die 286 carried by the die carrier'280. Rods 288 maintain the punch carrier and die carrier in properly aligned relation. A control device 290 similar to those heretofore disclosed operates through a connecting rod 292 laterally of the strip-44a to cause the punch 100a to shave a section of metal from the stock toenlarge each aperture 70a in accordance with a predetermined pattern and in accordance with the thickness of the strip stock. i

A further sub-press tool 294 similar to those heretofore described is similarly mounted by means of dovetail slides and guideways and includes a punch carrier 296 (Fig. 8) carrying a punch 298 (Fig. 9) It will be understood that there is also a. die carrier mounting a die having a rectangular aperture therein for receiving the punch 298;

A control device 300 is connected to the sub-press tool 294 by means of a connecting rod 302 to shift the tool laterally of the strip for shaving or enlarging each of the apertures 86a so that the apertures 86a and 70:; are of the same size and symmetrical about the center of the strip 44a, at any given transverse section of strip 44a.

A parting punch 304 is carried by the punch holder 220 near the discharge end thereof and cooperates with a rectangular opening in a parting die carried by the die shoe 222 for parting the strip into pairs of E-shaped 1am. inations 132a and 134a along the lines 128a and 130a in the same manner as previously described with regard to the first embodiment of my invention. y it will be understood that suitable stacking chutes can be, and preferably are, placed beneath the die chute 222' and supporting bolster (not shown) for automatically stacking the E-shaped and I-shaped laminations. Suitable stripper plates, of various designs commonly used, are incorporated in the various sub-presses.

By 'the practice of my invention as herein disclosed it is possible automatically to fabricate laminated ferro-' magnetic cores for transformers and the like, these cores 7 automatically determined in size according to their intended position in a finished staclcof laminations making up a ferromagnetic core.

'Two particular embodiments of my invention have been; shown and described. It will be understood that these two embodiments are by way of illustration and are not. by way of limitation. Other embodiments are possible and come within the scope of my invention insofar as they fall within the spirit and scope of the appended claims.

I claim:

1. Apparatus for making ferromagnetic core lamina-- tions comprising means for feeding ferromagnetic sheet stock means having a thickness and corresponding in; extent to a plurality of core laminations along a predetermined path, means along said path for forming pairs of elongatedparallel openings in said sheet stock means, means for varying the spacing between successive pairs of openings in accordance with a predetermined pattern and a thickness of said stock, and means for operating said feeding means, said forming means, and said varying means in timed relation. p v

2. Apparatus for making pairs of E and I shaped ferromagnetic core laminations comprising means for feeding ferromagnetic sheet stock means having a finite thick with a predetermined pattern and the thickness of said stock, means for enlarging the openings left by the removal of said stock in accordancewith a predetermined pattern and the stock thickness, and means for separating the stock at intervals to form E-shaped laminations.

3. Apparatus for making ferromagnetic core laminations comprising means for feeding a strip of ferromagnetic stock along a predetermined path, means at a first station along said path for forming a succession of elongated openings in said strip spaced apart longitudinally of said strip, means at a second station along said path for forming a succession of second elongated openings coextensive with and parallel to said first openings and laterally spaced therefrom, the openings defining the interior portions of pairs of confronting E-shaped laminations, means for relatively varying the position of said strip and said forming means laterally of the openings for varying the spacing between successive pairs of first and second openings according to a joint function of the thickness of said stock and a predetermined pattern, and means for severing the strip at intervals to form a plurality of E-shaped laminations.

4. Apparatus for making ferromagnetic core laminations comprising means for feeding a strip of ferromagnetic stock along a predetermined path, means at a first station along said path for forming a succession of elongated openings in said strip spaced apart longitudinally. of said strip, means at a second station along said path for forming a succession of second elongated openings coextensive with and parallel to said first openings and laterally spaced therefrom, the openings defining the interior portions of pairs of confronting E-shaped laminations, means for relatively varying the position of said strip and said forming means laterally of the openings for varying the spacing between successive pairs of first and second openings according to a joint function of a predetermined pattern and the thickness of said stock, means for enlarging certain successive pairs of the first and second openings to achieve a mutual relationship between edges of the resulting openings according to a predetermined pattern, and means for severing the strips at intervals to form a plurality of E-shaped laminations..

5. Apparatus for making ferromagnetic cores as set forth in claim 4 wherein the means for varying the spacing between successive pairs of first and second openings and means for enlarging certain of the openings comprise means for laterally shifting the strip in accordance with a joint function of predetermined patterns and the;

thickness of said stock.

6. Apparatus for making ferromagnetic core laminations as set forth in claim 4 wherein the means for varying the spacing between successive pairs of first and second openings and for enlarging certain pairs of said openings comprises means for shifting the opening forming means and the enlarging means laterally of the strip in accordance with joint functions of predetermined patterns and the thickness of said stock.

7. Apparatus for making ferromagnetic core laminations as set forth in claim 4 wherein the strip is fed along a straight path and the first and second opening forming means and the opening enlarging means are spaced longi-..

tudinally along said path.

8. Apparatus as set forth in claim 4 wherein the first and second opening forming means and the opening enlarging means are disposed laterally of one another and the strip is fed past the opening forming and enlarging means in a series of loops.

9. Apparatus for making ferromagnetic core laminations comprising a punch press, means for feeding a strip of ferromagnetic stock through said punch press, a cooperating punch and die carried by said punch press for stamping a first series of I-shaped sections from said strip to form I laminations, a second cooperating punch and die carried by said punch press for stamping a second series of rectangular sections from said' strip to form additional I laminations, the openings left in the strip by punching out the first and second series of laminations, providing a series of pairs of openings of equal size in said strip, said pairs of openings being coextensive and parallel and forming the interior portions of pairs of confronting E laminations, means for relatively shifting said strip and both of said cooperating punches and dies to vary the spacing between said openings in accordance with a joint function of a predetermined pattern and the thickness of said stock, further cooperating punch and die means carried by said punch press for enlarging certain of said openings in accordance with a predetermined pattern, shearing means carried by said punch press for severing the strip at intervals to form a plurality of E- shaped laminations, and further including means for automatically stacking E-shaped laminations in accordance with the sequence in which they are formed.

10. Apparatus for making ferromagnetic core laminations comprising means for feeding a strip of ferromagnetic stock along a predetermined path, means at a first station along said path for forming successive elongated openings in said strip and spaced longitudinally of said strip, means at a second station along said path for forming a succession of elongated openings coextensive with and parallel to the first mentioned openings and laterally spaced therefrom, the openings defining the interior portions of pairs of confronting E-shaped laminations, means at another station along said path for removing slugs from said strip, means for arranging a plurality of said slugs in a column as they are stamped from said strip, means operable in accordance with the increment in height of said column for relatively varying the position of said strip and said forming means laterally of the elongated openings for varying the spacing between successive pairs of first and second openings according to the thickness of said strip, and means for severing the strip at intervals to form a plurality of E-shaped laminations.

11. Apparatus for working sheet material comprising means for feeding sheet material, material working means past which said sheet material is fed, means for locating said material working means in predetermined position,

means for removing sections from said sheet material, means for locating said section removing means in predetermined position, a pair of endless chains having confronting, substantially vertical reaches, cooperating carriers on said endless chains confronting one another in pairs along said substantially vertical reaches and receiving the sections removed from said sheet material for driving said chains, and means controlled by the movement of said chains for relatively shifting said sheet material and said material working means for controlling the portions of the sheet material to be worked in ac-' cordance with the thickness of said sheet material.

12. Apparatus as set forth in claim 11' wherein the cooperating carrier means includes pairs of confronting members on the opposite chains, the members on one chain having a supporting shoulder near the top thereof, an underlying inclined surface and an overlying inclined surface substantially parallel to one another, and the members on the other chain having an overlying shoulder, an inclined surface extending outwardly beneath said shoulder, and a surface above said shoulder substantially parallel to the underlying surface, the inclined surfaces of opposite members being substantially parallel and spaced in accordance with the distance across the sections removed from the sheet material, and the shoulders on opposite members being vertically spaced apart a distance at least as great as the thickness of a plurality of the sections removed; the sections removed thereby being supported by one of the shoulders of the first mentioned members and on one another.

13. Apparatus as set forth in claim 12 wherein the means for relatively shifting the material working means and the sheet material includes power multiplying means. 14. The method of forming ferromagnetic cores which.

ness of said stock, enlarging certain of said openings in accordance with a predetermined pattern and a thickness of said stock, cutting off the stock at intervals to form E-shaped laminations, stacking the laminations to form E-shapedcore portions having circular center legs, and arranging the material removed from the strip in stacks of I-shaped laminations across the ends of the legs of the E-shaped core portions to complete the cores. 15. Apparatus for making pairs of E and I shaped ferromagnetic core laminations comprising means for feeding ferromagnetic sheet stock means having a finite thickness and corresponding in extent to a plurality of pairs of E and I shaped laminations along a predetermined path, means along said path for removing rectangular sections of stock to form the I-shaped laminations and to :form the interior of said E-shaped laminations, means for varying the spacing between the open ings left by the removal of said stock in accordance with a predetermined pattern and the thickness of said stock, means for enlarging the openings left by the removal of said stock in accordance with a predetermined pattern and the stock thickness, and means for separating the stock at intervals to form E-shaped laminations.

16. Apparatus for making ferromagnetic core laminations comprising a punch press, means for feeding a strip of ferromagnetic structure through said punch press, a cooperating punch and die carried by said punch press for stamping a first series of I-shaped sections from said strip to form I laminations, a second cooperating punch and die carried by said punch press for stamping a second series of rectangular sections-from said strip to form additional I laminations, the openings left in the strip by punching out the first and second series of laminations providing a series of pairs of openings of equal size in said strip, said pairs of openings being coextensive and parallel and forming the interior portions of pairs of confronting E laminations, means for relatively shifting said strip and both of said cooperating punches and dies in accordance with a predetermined pattern and in accordance with the thickness of the stock,

further cooperating punch and die means carried by said punch press for enlarging certain of said openings in accordance with a predetermined pattern and in accordance with the thickness of the stock, and shearing means carried by said punch press for severing the strip at intervals to form a plurality of E-shaped laminations.

17. Apparatus for making ferromagnetic core lamina tionscomprising means for feeding ferromagnetic sheet stock means having a thickness and corresponding in extent to a plurality of core laminations along a predetermined path, means along said path for forming successive sets of paired non-overlapping openings, the numberof paired openings in a set being equal to atleast one, any excess of paired openings beyond 'one being overlaid on the first pair of openings formed insaid sheet stock means so as to eifect enlargement of each' of the openings in said first pair of openings, means associated with at least one of said paired openings forming means to vary the spacing between successive pairs of openings in accordance with a predetermined pattern and in accordance with the thicknessof thesheet stock,"

means, and means for parting said sheet stock means to produce pieces each having no more than one set of said paired non-overlapping openings.

References Cited in the file of this patent UNITED STATES PATENTS 1,040,265 Bosler Oct. 8, 1912 1,292,323 Hyatt Jan. 21, 1919 1,302,249 Vogetzer Apr. 29, 1919 1,441,359 Langston Jan. 9, 1923 1,582,052 Klages Apr. 27, 1926' 1,666,344 Ovestrud Apr. 17, 1928 1,729,123 Philip Sept. 24, 1929 1,736,049 Nordendale Nov. 19, 1929 1,775,401 MacMillan Sept. 9, 1930 2,054,831 Peters Sept. 22, 1936 2,302,571 Ray Nov. 17, 1942 2,357,017 Miller et al Aug. 29, 1944 2,489,977 Porter Nov. 29, 1949 2,667,925 Dalphone Feb. .2, 1954 FOREIGN PATENTS 141,652 Switzerland ...l Oct. 16, 1930

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