US2160589A

US2160589A - Apparatus for making strip wound magnetic cores

Info

Publication number: US2160589A
Application number: US123250A
Authority: US
Inventors: John C Granfield
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1937-01-30
Filing date: 1937-01-30
Publication date: 1939-05-30
Anticipated expiration: 1956-05-30
Also published as: DE722211C

Description

y 1939- J. c. GRANFIELD 2,160,589

APPARATUS FOR MAKING STRIP WOUND MAGNETIC CORES Y Filed Jan. 30, 1937 2 Sheets-Sheet l Inventor John C. Granfield y Wan/1 6.,

HLS Attowneg,

May 30, 1939. J. c. GRANFIELD APPARATUS FOR MAKING STRIP WOUND MAGNETIC CORES Filed Jan. 30, 1937 2 Sheets-Sheet 2 Ifwevfliov v John C. Gvanfield m7 III HIS Attorney.

Patented May 30, 1939 UNITED STATES APPARATUS FOR MAKING s'mrr WOUND MAGNETIC corms John C. Graniield, Pittsfield, Mass" assignor to General Electric Company, a corporation of New York Application January 30, 1937,Serial No. 123,250

10 Claims.

In my copending application, Serial No. 123,249,

filed concurrently herewith,.I have disclosed and claimed certain improvements in electro-magnetic induction apparatus such as transformers and reactors, and the method of making the same, and I have disclosed but not claimed therein the machine for making such apparatus, such machine constituting subject matter claimed in the present application. This application, like the application filed concurrently herewith, is a continuation-in-part of my application, Serial No. 77,499, filed May 2, 1936.

My invention relates particularly to a machine for applying strip wound magnetic cores to transformers, reactors and the like. In accordance with the method disclosed in my copending applications the strip wound core is adapted to be applied to form wound conductive winding structures. My machine is adapted to apply strip -01? various composition and thickness. One kind of strip which may be very easily applied by my machine is strip of high reduction cold-rolled silicon steel containing about 3% silicon. This strip may be obtained from the mill in long 5 lengths and long lengths may also be made by welding shorter strips end to end. In accordance with the method disclosed in my applications, the strip is wound spirally to form a hollow cylinder containing the exact amount of magnetic material required for one of the spirally w und core elements of a transformer. The inside and outside dimensions of the tightly wound coil of strip are made exactly the same as the dimensions that the completed core element is to have in the transformer. After such a coil of strip has been wound the end of the outside turn of the strip is secured to the next underlying turn of strip, preferably by tack welding it thereto, and the coil of magnetic strip in this form is placed in a heat treating oven which gives the coil of strip a permanent set. The high reduction. cold-rolled silicon strip has the most favorable magnetic orientation of the grain in the direction in which the strip has been rolled. The heat treatment of such a coil of strip for at least an hour at a temperature of about 800 C. to about 900 C. in the heat treating oven assists in developing the favorable magnetic characteristics of the strip as well as g ving it a perform a loop having a circumference considerably greater than the outside circumference of the heat treated coil. The end of the strip of the large loop is secured-to the next underlying turn of the strip whereupon, by rotation of the heat treated coil together with the large loop, the strip is unwound from the heat treated coil and wound on the inside of the large loop. After all of the strip has been coiled into the larger loop the tack weld is loosened and the. larger loop collapsed upon the leg of the conductive winding structure, and in the completed core element the coil of strip has the exact dimensions that it had when heat treated. In accordance with such method of application, the

strip can be applied so that when the core element has been completed it is free from elastic strains which would impair its magnetic qualities.

My invention will be better understood from the following description taken in connection with the accompanying drawings in which Figs. 1 and 2 show an early step in the application of a coil of magnetic strip to a transformer, the figures being alike except that they show different constructions of the transformer conductive windings; Fig. 3 shows an intermediate step of the operation; Fig. 4 showsa later step in the operation, and Fig. 5 shows the final step in the operation of winding the strip on to the transformer; Fig. 6 shows in perspective with parts broken away, one form of machine embodying my invention; Fig. 7 is a view taken generally from the left of Fig. 6 showing parts of the machine; Fig. 8 is a perspective view showing certain elements of the machine; Fig. 9 is a view showing a part of the machine of Fig. 6; .and Fig. 10 shows a detail of one of the elements of the machine.

Referring to Fig. 1, a transformer conductive winding structure to which a coil of magnetic strip is to be applied is shown in cross-section. The winding structure shown in Fig. 1- is of the general type shown in perspective in Fig. 6. This transformer comprises for example a primary winding i0 and two secondary windings II and I2 located concentrically with the primary winding, the windings H and I2 being. respectively outside and inside of the winding Ill. The window through which the strip is to be carried and wound about the right-hand leg of Fig. 1 is indicated at 13." The sides of the winding structure or winding legs as they may be called are each provided with suitable insulation having circular contour, such insulation being inbe applied is shown at I5.

dicated at l4. The coil of magnetic strip to In the stage of operation shown in Fig. 1 the end of the coil of strip has been carried through the window l3 in the direction of the long arrow and curved into the form of a large loop I 6' and secured to the next underlying turn of strip, .as for example by tack-welding, at H. In my machine the coil of strip I5 is placed over a roller l3 engaging-the inside of the coil, and a roller I3 is provided to engage the outside of the coil. As hereinafter described, means are provided for biasing the roller [3 toward the roller l9 so that the coil of strip is gripped between these rollers which are provided with surfaces of rubber or the like to reduce slipping. The rollers l8 and I! are driven simultaneously and in opposite directions, as indicated by the arrows shown on the rollers in the drawing. The rotation of the rollers turns the coil of strip I5 and turns the large loop IE to unwind the coil of strip i 5 and simultaneously rewind the strip into the larger loop l6, turns of strip. being successively added to the inside of ftheloop l6. To facilitate threading the strip through the window i3 and for another purpose hereinafter described, a guide plate 20 is provided. For a generally similar purpose, a roller 2| is provided to bear against the outside of the loop ii. To prevent any tendency of the strip to climb up between the rollers l3. and is during the winding operation, a roller 22 is provided bearing on the top edge of the coil I 5 and the top edge of the larger loop l6.

The showing of Fig. 2 differs from Fig. 1 only in.that the arrangement of the winding structure of the transformer to which the coil of strip is to be applied is somewhat different. In Fig. 2, the secondary windings II and I2 are located one on each side of the primary winding ID instead of concentrically on the inside and outside of the primary winding. Both winding structures illustrated give a substantially cruciform cross-section to the winding leg, the periphery having a stepped form approximating a circle. Fig. 3 shows a stage in the operation where nearly all of the strip has been unwound from the coil l5 and rewound into the large loop It. It will be observed that the number of layers of strip in the larger loop I6 is only about half as great as the number of layers originally in the coil IS. The inside of the larger loop turns freely through the window l3 even though a number of layers of strip have been placed within the outside turn of the loop l6. When the stage of operation shown in Fig. 3 is reached, a little further rotation of the rollers l8 and I9 releases the inside end of the strip which tends to curl around the insulating cylinder [4. The

operator may catch the end of the. strip by hand and hook it over the insulating cylinder l4 if it should fail to assume that position. The operator then removes the roller l8 and loosens up the tack weld I! which he may do by a screw driver or other implement. The large loop, by reason of the resiliency of the strip and its tendency to assume the position it occupied when heat treated, collapses to the general position shown in Fig. 4. The strip would assume a still more closed form if it were not for the friction of the edge of the strip'upon the table upon which the winding operation is carried out.

The operator then secures the inside end of the strip to the insulating cylinder I4 which he may conveniently do by clamping it by a small clamp. He then brings the oppositely rotating limited by the guide plate 23. The loop II, by

the rotation of the

rollers

23 and 24, is rapidly collapsed and the side of the loop touches the guide plate 20 only during the first few revolutions of the loop. The collapsing loop is followed up by the inward movement of the

rollers

23 and 24 and .in a very short time the loop is collapsed to its completed form as shown in Fig. 5 at 25. The collapsing of'the loop is assisted by the permanent set given the strip in the heat treating oven and since the outside diameter of the cylinder of insulation l4 was made exactly the same as the inside diameter of the heat treated coil IS, the completed coil of strip 25 remains in the completed-position after the

rollers

23 and 24 are removed. The outside end of the strip may then be tack welded to the next underlying' turn of strip at 23. The turns of strip in the completed coil 25 are in the same sequence that they werein the heat treated coil I5. In accordance with the method of applying the strip, it has not been strained beyond the elastic limit and the completed magnetic core is free from strains which would impair its permeability or watt loss characteristics.

Referring to Fig. 6, a completed transformer is shown in which two

cores

26 and 21 of magnetic strip have been applied to a winding structure. The tack-welds securing the outer end of the strip of the core 28 are indicated at 23. The transformer is ready to be lifted out of the machine preparatory to inserting a new winding structure to which magnetic cores are to be applied. The rollers l3 and I! described in connection with Figs. 1 and 3 are shown in Fig. 8, the roller l9 also being shown in Fig. 6. The guide roller 2| heretofore referred to for guiding the side of the large loop of strip is shown in Fig. 8 mounted on a member 29 adapted to be adjusted along the table 30 and clamped in any adjusted position by a wing nut 3'. The roller 22 heretothey may be swung toward and away from each other.

Before describing in greater detail the means for operating the various rollers, it will be helpful to describe how the winding structure to which the magnetic cores are to be applied is mounted on the machine and moved to the proper position for application of the strip cores. In the machine shown in Fig. 6, the transformer is clamped between four lower rollers 35 and four upper rollers 36. These rollers are preferably provided with a surface such as rubber so that they will not damage the transformer windings. The four lower rollers are mounted on a plate 31 pivotally supported as hereinafter described and the upper rollers 36 are mounted on a plate 33 which is pivotally mounted on a threaded rod 33 adjustable by a hand-wheel 40. The rod 33 is threaded .hand wheel 46 to lift the upper clamping rollers I is pivotally mounted.

- For simplicity in description I shall refer to the supporting member 42 with the parts mounted on the upper and lower'projecting portions 4| and 46 as the winding head. In the stage of operation shown in Fig. 6 the transformer has been finished. To release it the operator turns the 66 out-of engagement with the transformer windings. The transformer is then lifted out of the machine and another transformer winding structure to which magnetic cores are to be applied is placed so as to be supported by the lower rollers 35. The hand wheel 46 is then turnedto lower the plate "carrying the upper rollers 36 to clamp the winding structure in place between the upper and lower rollers. The upper plate 36 is prevented from rotation when the rod 39 is rotated bythe hand wheel 46, by a slidable rod 44 which carries a projection entering an opening in the member 36. There is an opening 45 in each end of this member. By raising the rod 44 sufficiently to lift the projection out of one of the openings 45 in the plate, the winding structure may be ro tated upon the pivotal mountings of the plates 31 and 3Lthrough 180, and it may be held in its new position by the entrance of the projection on rod 44 into the other opening 45.

After the winding structure has been mounted in the winding head as described it must be moved down into the table 36 a sufficient distance to bring the point on the winding structure where the bottom edge of the strip core is to be placed even with the surface of the table 36. To permit this vertical movement the supporting member '42 of the winding head is arranged to be moved vertically'on a support 46 which may be clamped in position on the table 36 as hereinafter described. Guiding roiiers 41 mounted on the supporting member 42' engage the side edges of the support 46 and rollers 46 mounted on the forwardly projecting-member 4| bear on the back of the support 46. A rack 49 is welded to the edge of the supporting member 42 and a pinion 56 operated by hand wheel 5| engages this rack to move the member 42 along the supporting member 46. The shaft for the pinion 56 and hand wheel 5| is mounted at the top of a support 52 secured to a member adapted to slide along and be clamped to the table 36 as hereinafter described. A clamping member 53 threaded into the member 42 and moving in a slot 54 in the member 46 is provided to clamp the member 42 to the member 46 in any adjusted position. When the operator wishes to lower the winding head, he loosens the clamping member 53 and operates a lever 55 to move a dog 56 away from the rack whereupon he can turn the hand wheel and lower the winding head into the table to the desired position. The lever 55 is operated to engage'the dog 56 with the rack 46 and the operator then clamps the members 42 and 46 together by the clamping member 53.

After having lowered the winding head to bring the conductive winding structure of the transformer into the proper position with respect to the top of the table 36, the operator lays the heattreated coil of magnetic strip to be applied to the transformer upon the table top and inserts the ro1ler|6 into the coil. To permit the roller Hi to be inserted and removed, it is provided with a projection 51 which enters a driving socket 56 rotatably mounted in' a member 56, as shpwn in Fig. 8. The roller is provided with a collar 66 entering the'socket 56. The edges of the socket are slotted and a pin 6| through the collar 66 enters the slots in the socket to provide a driving connection between the member 56 and the roller l6. The top of the socket 56 appears in Fig. 6'. To enable the roller |6 to be inserted in the coil of stripplaced on the table, it is necessary to move the socketed member 56 away from the roller I 6. To enable this to be done. the member 59 in which the socketed member 66 rotates is mounted on rods 62 and 56 sliding in bearings in the table 36. The outer ends of these rods are connected by a crosspiece 64. This cross-piece 64 has an opening through which a guide pin 65 mounted ona member 66 secured to the table 66 projects so that the pin 65 guides the cross-piece 64, preventing the rods 62 and 63 from binding in the bearings of the table 36.

Springs

61 and 66 are provided on the rods 62 and 63 between the table 36 and the cross-piece 64 to bias theroller |6 toward the roller l6 by biasing the member 56 carrying the driving socket 56 toward'the right in Fig. 6. To move the socket 56 away from the roller I! to permit the insertion of .the roller II, the operator raises a lever 66 which moves the outer end of a crank 16 downwardly.- The outer end of this crank is secured to a cable or chain H passing over a pulley I2 and secured to the cross-piece 64. Raising the lever 66 therefore 1 moves the cross-piece 64 and rods 62 and 63 to the left in Fig. 6, .thus moving the supporting member 59 carrying the socket member 56 to the left. A pawl 13 is moved into engagement with teeth 14 on a member on the shaft of the lever 69 and crank 16 to hold the socket 56 in the position to which it has been moved against the b as of the

springs

61 and 66.

After the operator has placed the roller I6 in position in the coil of strip and threaded the strip through the window in the winding structure and formed the large loop l6, as described 1 and 2. The roller 19 is mounted in a bearing in the table 36 and is driven by a pinion which is in turn driven by a gear '16 as shown in' Fig. 8.

The gear 16 is mounted at the top of a shaft I? which in the machine shown in Fig. 6 is driven through bevel gears 16 by a motor 19 operating through pulleys and a belt 86 and a friction clutch 6|. The clutch is a shifting .clutch controlled by a foot lever 82.

The roller I 6 as shown more clearly in Fig. 8 is driven by the pinion 12 through gears 63 and 64, the gear 84 engaging a gear 85 at the lower end of the socketed member 58 turning in the member 59. The axis of the gear 83 is fixed to the table 36. The gear 64 is floatingly mounted to permit horizontal movement of the gear 65 when the member 59 is shifted to move the position of,the socket 56 as heretofore described. To

permit of this floating movement the gear 64 is mounted between links which are pivoted respectively on the axes of the gears 63 and 64,

era I3 and I9 for the strip'winding operation,

' the operator places the roller '22 in place to bear on the upper edges of the strip as heretofore described in connection with Figs. 1 and 3.

'When'the coil of strip has been unwound into the larger loop just beyond the position shown in Fig. 3, the operator stops the rotation of the rollers II and I9 andremoves the roller I8, whereupon the sta'ip takes the position shown in Fig. 4. The operator then breaks the tack weld securing the outer end of the strip tothe next underlying strip, secures the end of-tne inside turn to the in; sulating cylinder I4 as heretofore described, and brings the

rollers

23 and 24 into position to collapse the strip. To bring the

rollers

29 and 24 into this positiomthe operator moves the lever 93 which through the link 99 and a link which does not, appear; in Fig. 6 turns the member 90 pivoted at its center at 9I. The ends of the member 99 are connected through members 92 and 93 to members which swing the

rollers

23 and 24 into and out of position. These

rollers

23 and 24 are mounted at the outer ends of arms 94 and 95 pivoted at the back of the machine, the pivot point for, the arm .94 being shown at 93. l 'he members 92 and "operated from the lever 99 as heretofore described, swing the arms 94 and 95 about their pivot points. The connection between the member 92 and the arm 94 is indicated v at 91, the member 91 being rigidly secured to the lower member of the arm 94. This lower' member of the arm 94 does not appear in Fig. 6

but the lower member of the arm 95 is shown in Fig. 6.

To rotate the

rollers

23 and 24,

belts

99 and 99 are provided operating over pulleys. The.

driving pulleys are-mounted on the axes of the pivoted arms and driven through suitable gear m'eclianism.

The gear mechanism for driving the pulleys on the arm 94 consists of a pair of bevel gears I00 .provided for driving the roller 23, but the gears do not appear in the drawings except that a pinion I05 on the driving shaft I99 and engaging the'gear- I04 does appear in Fig. 8.

The strip being in the position shown in Fig. 4 and the

rollers

23 and 24 moved against the strip, as shown in Fig. 4, the rotation of the rollers collapses the strip to its completed position shown in Fig. 5, as heretofore described. To follow up the collapsing loop, the operator continues to move the lever 99 to swing the arms 94 and 95'inwardly. To provide a gentle and yielding engagement of the

rollers

23 and 24 with the loop of strip, the members 92 and 93 are preferably constructed as shown in Fig. 10. These members comprise a cylinder I" in which a plunger I09 moves. A spring I09 is provided tending to'move the plunger out of the cylinder. The construction provides a kind of yielding dash-pot connection.

I19 through the plunger III in the cylinder..

To an partially the opening in the table top The relative motion of the plunger and the cylinderis by a whifli moves of one of the magnetic cores upon the trans-- former, he lifts the winding head by operating the hand-wheel 5|, as heretofore described. The winding head is secured in its upper position by the dog 59 engaging the rack 49, whereupon the operator lifts the rod 44 and turns the winding structure through 180 degrees, as heretofore described, at which position the rod 44 engages the opening in the other end of the member 33. The operator then lowers the winding head to the proper position and proceeds to apply the other core to the winding structure in the manner heretofore described.

To accommodate various sizes of winding structures and to adjust the distance between the winding structure and the rollers I8 and II for various diameters of the large loop IS, the winding head is made bodily movable longitudinally of the table. To accomplish this forward and backward movement, a hand-wheel H4 is prm vided which operates pinion II5 engaging a rack IIG secured to the member III which slides on the table top 39 as is more clearly shown in Fig. 7.

To clamp the winding head to the table in any adjusted position a member -I I II is provided which extends through thelower part of the support 43v and is threaded into a plate I I9 bearing on 'the bottom surface of the table top. When the member H9 is tightened, the table top is clamped between the members I I I and H9. Since the transformer mounted in the winding head is heavy and since all of its weight is in front of the winding head, the winding head tends to tip forwardly which tendency would cause the members I I1 and I I9 to bind on the table top interfering with free in adjusted position by a longitudinal adjustment of the winding head.

To overcome this tendency a member I 20 is bolted or otherwise secured to the member I" and this member L20 has two forwardly projecting members one of which is shown at I2I. At the forward ends of these members I 2| rollers are mount ed, one of which is shown at I22 in Fig. 6. These rollers bear upon tracks on the supporting plate I24. One-of the tracks is shown at I23. The supporting plate I24 also supports various parts of the mechanism heretofore described including table so. a

While I have shown a particular construction of machine which I have found well adapted for the purpose described, it will be apparent to those skilled in the art that many changes and modiflcations may be made without departing from the spirit and scope of my invention and I therefore aim in the appended claims to cover all such changes and modifications.

7 What I claim as new and desire to secure by Patent of the United States is: 1 A'machine for applying strip wound magnetic cores to winding structures comprising means for holding the winding structure in position to be wound, means for supporting a coil of magnetic strip, said ,means being spaced away from the winding structure a suflicient distance to permit a relatively large loop of strip from said coil to be threaded through said winding structure, said means comprising oppositely rotating rollers engaging the inside and outside of the coil of strip to rotate the coil and drive the strip to unwind the coil and rewind the strip material into the larger loop, and means for biasing the oppositely rotating rollers toward each other to grip the turns of strip located between the rollers.

2. A machine as set forth in claim 1 comprising means for collapsing the turns of the large loop upon the winding structure.

3. A machine as set forth in claim 1 including means for engaging the edge of the strip to prevent movement of the strip along the rollers which drive the strip.

4. A machine of the class described comprising means for unwinding a flatwise spirally wound coil of strip and simultaneously rewinding it into a larger coil around an object out-side the origi-- nal coil comprising oppositely driven rollers engaging the inside and outside of the coil, power driven rollers for collapsing the larger coil, and means for moving the coil-collapsing rollers inwardly as the coil collapses.

5. A machine for assembling a winding and a magnetic core 01' the wound type, said machine including means for supporting the winding. means comprising a rotatable roller for supporting a wound coil of magnetic strip with its axis parallel to one side of the winding means for pressing the coil of strip against said roller, and means for rotating said roller to unwind said coil and simultaneously rewind it around one side of the winding.

6. A machine for assembling a winding and a magnetic core oi. the wound type, said machine comprising means for supporting the winding and means comprising a roller for supporting a coil of magnetic strip material, a second roller movable toward and away from the first roller, means for biasing said rollers toward each other to grip the coil of strip therebetween, and means for rotating one of said rollers to unwind said coil and simultaneously rewind it around one side of the winding.

7. A machine for assembling a winding and a magnetic core of the wound type, said machine comprising means for supporting the winding at a given position, means for supporting a wound coil of magnetic material beside said position, I

means for rotating said coil to unwind it into a loop around one side of the winding and means for guiding said loop.

8. A machine for assembling, a winding and a magnetic core of the wound type comprising a supporting table, a roller mounted for rotation on said table, a second roller biased toward the first roller, means arranged to move said roller against its bias to separate the rollers, said second roller being removably mounted to permit a coil of magnetic strip to be placed on the table and the roller thereafter inserted into the coil, said rollers being geared together to rotate in opposite directions and means for rotating'the rollers to unwind said coil and simultaneously wind it around one side of the winding.

9. A machine for assembling a winding and a magnetic core of the wound type comprising means for winding a strip of magnetic material into a relatively large loop turning freely through the winding and means for collapsing the turns of the large loop about the winding comprising power driven rollers and means for swinging said rollers into and out of engagement with the turns to be collapsed, said means including yielding means to permit of yielding engagement between said rollers and the sides of theloop.

10. A machine for assembling a winding and a magnetic core 01' the wound type comprising a supporting table, a winding head and means for adjusting the winding head vertically with respect to the table, means for pivotally mounting the winding in the winding head and securing it in adjusted pivotal positions, means rotatably mounted on the table for rotating a strip of magnetic material through the winding and means for adjusting the winding head longitudinally of the table to vary the distance between the winding and said rotatable means.

JOHN C. GRANFIELD.