US3628241A

US3628241A - Method of making a wound core and apparatus therefor

Info

Publication number: US3628241A
Application number: US32634A
Authority: US
Inventors: Kozo Toyoda; Katutosi Akatu
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 1969-05-02
Filing date: 1970-04-28
Publication date: 1971-12-21
Anticipated expiration: 1988-12-21
Also published as: JPS4839610B1

Abstract

A magnetic steel strip is continuously fed into a cutting device which cuts the steel strip into a prescribed length. The cutting device is operated in response to a first metering device which meters the length of the magnetic steel strip to be cut, and cuts the steel strip into the prescribed length successively utilizing a compulsory hump forming device disposed at the feed-out side of the cutting device without stopping the feed of the magnetic steel strip. The cut magnetic steel strips are transferred to a feed-out device and further to a continuous winding device. By the winding device the cut magnetic steel strips are wound into a wound core in which the seam positions are overlapped by a prescribed length.

Description

O Unite States Patent i 1 3,628,241

[ 72] Inventors gozogioyoda [56] References Cited UNITED STATES PATENTS K t t k t k, f [21] APPLNQ 2 2 Japan 3,223,955 12/1965 Olsen etal. zsleosx [22] Filed Apnzs 1970 3,362,066 1/1968 Cooper 29/605 [45] Patented Dec.2l,l971 Primary Examiner-Travis S.lVlcGehee [73] Assignee Hitachi, Ltd. Attorney-Craig, Antonelli, Stewart & Hill Toky0,Japan [32] Priority May 2, 1969 33 Japan ABSTRACT: A magnetic steel strip is continuously fed into a {31] 44/33611 cutting device which cuts the steel strip into a prescribed [54] METHOD OF MAKING A WOUND CORE AND length. The cutting device is operated in response to a first metering device which meters the length of the magnetic steel strip to be cut, and cuts the steel strip into the prescribed length successively utilizing a compulsory hump forming device disposed at the feed-out side of the cutting device without stopping the feed of the magnetic steel strip. The cut magnetic steel strips are transferred to a feed-out device and further to a continuous winding device. By the winding device the cut magnetic steel strips are wound into a wound core in which the seam positions are overlapped by a prescribed length.

SHEET 1 OF 4 COU/VTB? SCH/W77 79/6656 E52;g ME E w AMPL/F/El? INVENTORS DA and KATuros: AKAI'M W; Jaw d M ATTORNEY3 PATENTED necz'r I97! SHEET 2 OF 4 w w 4 SI Q Q uwmi ffiwi INVENTORS K010 TovooA and KA TDsI AKA M M 7 W41 m ATTORNEY) PATENTED DECZT 1911 3.62824 1- SHEET 3 OF 4 I INVENTOR$ K010 TOYaDA and KAFUTOSI AKATM 4 M a W ATTURNEY BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of and apparatus for making a wound core used for an electric device such as a transformer, a current transformer for a meter and the like.

2. Description of the Prior Art In general, the wound core used for an electric device such as a transformer, a current transformer and the like is formed by rolling a magnetic steel strip into a loop having a prescribed internal diameter.

There are two kinds of method of making a wound core according to the use thereof. In one of the methods, a long magnetic steel strip is rolled a plurality of times into a loop having a prescribed internal diameter with a winding device. In the other of the methods of making the wound core, a plurality of magnetic steel strips cut into various prescribed lengths are wound in order into a loop having a prescribed internal diameter with a winding machine.

In the latter method wherein the wound core is formed from a plurality of steel strips, the steel strips are cut into the prescribed different length in advance. That is, in order to form a wound core which has no spacing between the convolutions, the respective pieces of the magnetic steel strips should have length computed. For example, in the case that the internal diameter of a wound core to be formed is D and the thickness of the steel strip is t, the magnetic steel strip wound in the innermost convolution should have length of l,("-'rrD) and the steel strip to be wound adjacent to the inner most one should have length of 1 which is longer than 1 by 2 1. Thus, the magnetic steel strips wound into the wound core should be cut into the length of 2 1" longer than the inner adjacent ones.

Accordingly, in the case of a wound core formed of n pieces of magnetic steel strips, there is a difference in length of 2 arm between the length l of the piece of the magnetic steel strip in the innermost convolution and the length 1,, of the piece in the outermost convolution thereof.

In view of the above fact, in the conventional method of making a wound core, a hoop-shaped magnetic steel strip has been cut with a steel strip cutter into pieces of steel strip having length differed by 2 wt in order. In the steel strip cutter used in the method as above, a steel strip carrier provided with a stopper for the steel strip is slidably mounted on a cutting board and the carrier is interlocked with a cutter so that the steel strip may be cut by the cutter when the steel strip is stopped by the stopper which is set at the prescribed position for determining the length of the piece of the steel strip to be formed into the wound core. In this case, there is a disadvantage that the cutting work can not be performed with high efficiency since the steel strip carrier should be moved to a different position every time it has completed cutting operation so as to change the length of the piece of steel strip to be cut in the next cutting operation.

Furthermore, there is such a disadvantage as follows in the conventional method of making a wound core. in the case that the wound core is required to be mounted to a primary conductor of a current transformer of hairpin shape or to a winding which is formed separately, after the wound core is formed of a plurality of pieces of magnetic steel strip cut into different length, the seam positions in the respective convolutions should be out of alignment with one other and be within a range so that the wound core may be easily formed and disassembled. In the conventional method of making a wound core, the winding operation can not be made with high efficiency, since the pieces of the magnetic steel strip should be carefully introduced into the winding machine which is driven intermittently.

Under the above-described disposition of the conventional method of making the wound core, a new and excellent method of and apparatus for easily and rapidly making a wound core from a plurality of pieces of steel strip have been desired to be developed.

SUMMARY OF THE INVENTION The principal object of the present invention is to provide a method of and apparatus for easily making a wound core used for an electric device such as a transformer, a current transformer for a meter and the like.

Another object of the present invention is to provide a method of and apparatus for making a wound core wherein a plurality of pieces of steel strip of different length are wound into a roll of strip by making the seam positions therein be out of alignment, that is, be overlapped by the prescribed dimension.

Still another object of the present invention is to provide a method of and apparatus for making a wound core wherein at least two groups of a plurality of pieces of magnetic steel strip are wound into a wound core and wherein the end of the first pieces in the respective groups are positioned in alignment with each other so that the seam positions are all within a prescribed range in order that the wound core may be easily disassembled.

A further object of the present invention is to provide a method of and apparatus for making a wound core wherein a plurality of pieces of magnetic steel strip can be continuously cut out with a cutter without stopping the feeding device and the feedout device for feeding a steel strip from a hoopshaped magnetic steel strip supply.

A still further object of the present invention is to provide a method of and apparatus for making a wound core wherein the cutting operation for cutting out various length of magnetic steel strips from a hoop-shaped magnetic steel strip and the winding operation for winding the strips into a core are performed in a serial operation.

The above and other objects and advantages of the present invention will be made apparent from the following description of the preferred embodiments of the invention.

The features of the method of and apparatus for making the wound core in accordance with the present invention lie in that the hoop-shaped magnetic steel strip supported with a rotatable supporting device is continuously fed into a cutting device with a feeding in device, the feeding in device is operated in response to a first metering device which meters the length of the fed in steel strip, the magnetic steel strip is successively cut into the prescribed length of pieces without stopping the feed-in operation utilizing a hump which is formed with a compulsory hump forming device disposed at the feed-out side of the cutting device, the hump forming device is actuated when the cutting device is started to be operated and is retracted when the cutting device finished operating, and the pieces of the steel strip are successively fed out and transferred into a continuous winding device which forms a wound core by overlapping the end of the strips so that the seam positions therein may be out of alignment, that is, the seam positions are overlapped.

BRIEF DESCRIPTION OF THE DRAWING HO. 1 is a front view of an example of a wound core formed in accordance with the method and apparatus of the present invention in which the seam positions of the wound strips are all out of alignment with one another,

FIG. 2 is a front view of another example of a wound core formed in accordance with another embodiment of the method and apparatus of the present invention in which the steel strips are divided into at least two groups and the end of the first strip in the respective groups are positioned in alignment with each other so that the seam positions may be within a range in order that the wound core can be easily disassembled,

FIG. 3 is a front view of still another example of a wound core formed in accordance with another embodiment of the method and apparatus of the present invention in which the same construction as that shown in FIG. 2 is formed in a rectangular shape,

FIG. 4 is a front view of the superposed pieces of magnetic steel strip used for making a wound core as shown in FIGS. 2 and 3,

FIG. 5 is a front view of the superposed pieces of magnetic steel strip used for making a wound core with an end of the respective pieces aligned,

FIG. 6 is a schematic view of an embodiment of the method of and apparatus for making a wound core in accordance with the present invention,

FIG. 7 is a schematic view of the apparatus shown in FIG. 6 with the winding device omitted at the state of cutting the magnetic steel strip,

FIG. 8 is a schematic view of another embodiment of the method of and apparatus for making a wound core in accordance with the present invention at the state of cutting the magnetic steel strip with the winding device thereof omitted.

FIG. 9 is a front view of the supporting device for supporting the hoop-shaped magnetic steel strip used for the method of and apparatus for making the wound core in accordance with the present invention,

FIG. 10 is a schematic front view showing the feeding in device, cutting device, compulsory hump forming device and feeding out device for the magnetic steel strip used in the method of and apparatus for making the wound core in accordance with the present invention,

FIG. 1 l is a front view of the continuous winding device for the pieces of magnetic steel strip used in the method and apparatus in accordance with the present invention, and FIG. 12 is a schematic view of an example of the metering device employed in the method and apparatus in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of and apparatus for making a wound core in accordance with the present invention is applied for making such wound .cores as shown in FIGS. 1, 2 and 3 from a hoopshaped magnetic steel strip by cutting it into pieces and winding them into a core. The wound core 1 shown in FIG. 1 is made of 10 pieces of steel strip 2 which all have different length and wound in order successively so that the seam positions may be all out of alignment with one another and the respective pieces may be lapped with the adjacent one by the length W. The wound core 1 shown in FIG. 2 is made of two groups 1a, 1b of five pieces of magnetic steel strip 2. The five pieces of magnetic steel strip 2 are all different in length in the respective groups 1a, lb. The two groups are wound into a core wherein the respective pieces are lapped with the adjacent one by the length W and the ends of the first strip in the respective groups are aligned with each other so that the seams may be within a limited range in order that the core can be easily disassembled. The wound core 1 as shown in FIG. 2 is formed in a rectangular shape as shown in FIG. 3 according to the use thereof.

The pieces of the magnetic steel strip 2 to be formed into a core 1 have different length as shown in FIG. 5 and as set forth above in the description of the prior art. The adjacent pieces of the magnetic steel strip 2 in the core 1 have difference in length of 2 m (t: thickness of the magnetic steel strip) and accordingly, the piece of the steel strip on the outermost convolution of the wound core is required to be cut into a length longer than that in the innermost convolution thereof by the length of m. In the present invention, such pieces of magnetic steel strip 2 are successively cut out from a hoop-shaped magnetic steel strip and wound into a wound core automati cally.

The schematic process and construction of the basic part of the method of and apparatus for making the wound core are shown in FIG. 6 and will be described in detail referring thereto. The apparatus 100 shown in FIG. 6 cuts out prescribed different length of pieces 11a from a hoop-shaped magnetic steel strip 11 of a proper width and winds the cut pieces 110 into a wound core 12. The apparatus consists of a supporting means 20 for rotatably holding the magnetic steel strip 11 such as an uncoiler, a feeding in means 30 for feeding the magnetic steel strip 11 into the subsequent process, a first metering means 40 for metering the length of the fed in strip 1 1, a cutting means 150 provided with a cutter 151 for cutting the fed in steel strip 11 into a prescribed length of pieces of magnetic steel strip 11a in response to the output from the metering means 40, a hump forming means 60 for making the continuous cutting operation easy, a feeding out means 70 for feeding out the cut pieces 11a of the magnetic steel strip, and a continuous winding means 80 for winding the cut pieces 11a of the magnetic steel strip into a wound core 12.

In operation, the hoop shaped magnetic steel strip 11 supported on the rotatable supporting means 20 is fed into the cutting means 150 provided with a cutter 151 through a couple of

feed rollers

31 and 32 of the feeding in means 30. At this moment, the length of the fed steel strip 11 is metered with a metering means 40 consisting of, e.g., a feed roller 41 disposed between the supporting means 20 and the cutting means 150 and the meter 42 connected therewith. In response to the output of the metering means 40, the cutting means 150 provided with the cutter 151 is operated to cut the magnetic steel strip 1 1 into the prescribed length of cut pieces 110. Thus, a plurality of cut pieces 1 la of the magnetic steel strip 11 are obtained. The length of the cut pieces 11a is so made that the first one is l, and the second one is l+21rt, and then the third one is I+41rr and so on. The cut pieces 1 1a are then fed out with the feeding out means 70.

In the cutting process wherein the magnetic steel strip 11 is cut into pieces by the cutting means provided with a cutter 151, the hump forming means 60 disposed at the feedout side of the cutting means 150 for forming a hump in the strip 11 is utilized as shown in FIG. 7 in order to continuously cut the strip 11 and feed the cut pieces 11a out towards the winding means 80 without stopping the feeding in operation.

Now the operation of the compulsory hump forming means 60 will be described. The hump forming means 60 comprises a couple of hump forming members 61 and 62 one of which has a positively curved surface and the other of which has a negatively curved surface and a driving means for moving at least one of the couple of members 61 and 62 up and down. The couple of hump forming members 61 and 62 are normally disposed to provide a spacing for passing the magnetic steel strip therethrough as shown in FIG. 6 so that the fed in strip 11 is humped between the upper hump forming member 62 and the lower hump forming member 61. When the cutting means 150 is operated to cut the strip 11 in response to the output of the metering means 40, the compulsory hump forming means 60 is operated to release the strip 11 therein as shown in FIG. 7. When the hump forming 60 is operated to release the strip 11, that is, when the lower hump forming member 61 is retracted downward, the magnetic steel strip 11 is temporarily stopped until the superfluous length at the hump is transferred into the feeding out means 70. While the magnetic steel strip 11 is stopped at the cutting means 150, the cutter 151 cut the strip 11 into the piece 11a of the magnetic strip. Since the strip 11 is continuously fed into the cutting means 150 while the cutter 151 is cutting the strip 11, there is formed another hump at the cutting means 150. That is, the hump is formed since the end of the strip 11 is stopped by the cutter blade while the strip 11 is continuously fed in by the feed-in roller 30. After the cutter 15 1 completed the cutting operation, the humped strip 11 is straightened by the elasticity thereof and the straightened strip 11 is again humped by the compulsory humping means 60. By repeating the above serial operations, the magnetic steel strip 11 is cut into the pieces of the steel strip 110 of the prescribed length continuously without stopping the feed-in operation of the feeding in means 30.

The cut pieces 1 1a of the magnetic steel strip 11 cut into the prescribed length are continuously fed out toward the continuous winding means through a couple of feed rollers "l1 and 72 of the feeding out means 70. In the continuous winding means 80, a plurality of pulleys 82, $3, 84, d5, 86 and 8'7 are disposed around a spool 81 and an endless belt m3 is guided along the path around the spool 81 and the

pulleys

82, 83, dd, M, as and b7. A tension exerting means 89 is disposed to exert tension on the endless belt 8% running around the pulleys M2, @33, Ml, d5, $6 and $7. The plurality of pieces llla of the magnetic steel strip lll fed into the winding means M) are wound into a wound core and end of the last piece Illa of the strip 111 is fixed to the core by spot-welding. Thus, the wound core is completed.

In accordance with the above-described method of making a wound core, it becomes possible to easily and rapidly make a wound core with high efficiency through a serial process from a hoop-shaped magnetic steel strip 11.

In order to make a wound core as shown in FIGS. 1, 2 and 3 wherein the seam positions are out of alignment with one another by overlapping the end of the pieces lllla of the strip 1 l, the running speed V of the endless belt 38 of the winding means Ml is made higher than the speed V of the feeding of the strip at the feeding out means 70 and the feeding in means 30 by the speed corresponding to the length W of the strip 11 so that the overlapped length may be as long as W.

Instead of the above-described method wherein the speed V, is made higher than the speed V so that the speed at the winding means may be higher than the speed at the feeding in and feeding out means, a method can be effected wherein the both speeds are made equal and the thickness of the cutter blade of the cutter l5ll at the cutting means 150 is made as thick as W as shown in FIG. 8 so that there may be spacings between the adjacent pieces lllla fed through the feeding out means. Thus, the overlapping of the pieces 11a in the wound core can be easily obtained.

In the case of making a wound core as shown in FIGS. 2 and 3 wherein the seam positions are within a limited range as that the wound core may be easily disassembled, the feeding in means 30 and the cutting means 150 are stopped after the first group of the cut pieces of the magnetic steel strip is wound up by the continuous winding means 80, and the feeding in means 30 and the cutting means 150 are started to be operated again when the end of the first piece in the first group now wound in a half wound core comes to the position aligned with the end of the first piece of the second group to be wound.

The respective means constructing the apparatus 111MB for making the wound core will be described in detail referring to FIGS. 9 through 112.

The supporting means 20 is shown in FIG. 9 which shows an embodiment thereof. A rotatable frame 22 is mounted on a supporting framework 21. On the rotatable frame 22 are provided supporting members 23 for holding the magnetic steel strip 111 in a hoop shape. A loop controller 24 for controlling the loop of the fed out strip 11 is mounted on the supporting framework 21. According to the angle of the loop controller 2d, the magnitude of the loop is detected and the motor (not shown) for rotating the rotatable frame 22 is operated to be started and stopped.

The feeding in means 30 for the magnetic steel strip Til, the first metering means 40, the cutting means llfil] for cutting the strip 111 into the prescribed length of pieces lllla of strip, the compulsory hump forming means 60 and the feeding out means 7th for feeding the pieces Illa of the strip into the winding means 30 are mounted on a base 101 as shown in FIG. 10.

The strip feeding in means 30 is constructed for instance by a guide roller 34!, and a couple of pairs of

feed rollers

31 and 32 mounted in a framework 33. The metering means for metering the strip 11 is constructed by a pair of metering rollers il disposed between the

feed rollers

31 and 32 of the feeding in means 30 and a meter d2 connected with the metering rollers ii. The meter 42 is electrically connected with the cutting means 150 for actuating the cutting means 150 with the output thereof. The position for metering the length of the fed in strip lll is not always required to be in the feeding in means 3t), but may be in the cutting means llfill just before the cutter therein.

As the meter d2, of the metering means M, a pulse generator as shown in FIG. 12 is used for instance. The pulse generator comprises a light source 43, a phototransistor M to receive the light from the light source d3, a lens Mb to condense the light from the light source d3, 2. light interceptor dill having a hole Alba to pass the condensed light therethrough. and a disc M! which has a plurality of slits to pass the light thercthrough and is rotated in meshing engagement with the metering rollers M. The pulse in a sinewave form detected by the phototransistor M is amplified by the amplifier 415i and put into the counter 417 through the Schmitt trigger as which shapes the pulse in a sinewave form into a pulse of rectangular shape. By the counter 47, the length of the magnetic steel strip 111 fed into the cutting means is metered, e.g., by making one pulse correspond to 0.1 mm. of the strip 11. At the moment when the counter 37 meters the prescribed length of the strip llll, the counter 4W is operated to transmit the output to the operation control circuit (not shown) of the cutting means 115i As the meter 42 of the metering means so, a step motor and the like can be used instead of the above-described construction as shown in FIG. 12.

The cutting means operated in response to the output from the metering means 45'!) is constructed as shown in FIG. MD for instance. In the construction shown in FIG. ill a supporter is vertically mounted on a base 1M, and on the supporter 1553 there are mounted a lower cutter blade 11% and a guide 153 for guiding a holder 1W2 holding an upper cutter blade i511 slidably moved up and down. The cutter holder 1152 is connected with a cutter driving means use. As for the cutter driving means 1156, a cylinder operated by compressed air is used for instance in order to quickly move the cutter blade 1151. The cutter driving means 156 and the cutter holder 152 holding the cutter TM are connected with each other through a first and second levers 157 and 15b for transmitting the movement from the fonner to the latter. At the axis of rotation 159 of the first lever 157 is mounted a bearing loll). The bearing lltii) is engaged with a groove 163 provided on the slidable member 162 which is slided by an auxiliary driving means 161. The auxiliary driving means 161 is constructed by a cylinder operated by compressed air and the like and is operated after the cutting operation is completed by the cutter 1151 in order to cut the magnetic steel strip 11 under the same condition. The grove T63 of the slidable member M2 is formed in the shape of deformed Z so that the axis of rotation 159 of the first lever 1157 is moved up and down in response to the sliding movement of the auxiliary driving means 161. On operation of the cutting means as described above, when the cutter driving means 156 is moved leftward in F i0. 10 in response to the output of the metering means til, the first lever 1157 and the second lever 11533 are rotated about the axis 159 in the counterclockwise and clockwise directions respectively and the cutter blade llfl ll is moved down to cut the magnetic strip llll running thereunder. When the first lever 157 reaches the left end of the stroke thereof, the lever 157 actuates a microswitch SW which is electrically connected to the control circuit (not shown) for the power of the auxiliary driving means 161 and then the auxiliary driving means M51. is operated. In response to the operation of the auxiliary driving means M51 wherein the slidable member 162 is slided leftward, the axis of rotation 159 of the first lever 157 in engagement with the groove I63 of the slidable member 162 is moved up. According to the moving up of the axis 159 of the first lever 157, the first lever 157 itself and the second lever lSh are also moved up. The moving up of the first lever 157 and the second lever 11% is detected by the microswitch SW The detection by the microswitch SW is transmitted to the cutter driving means R56 and the driving means 156 is moved back to the right. When the cutter driving means R56 is moved to the right end to rotate the first lever 157 clockwise to the limit end thereof, the microswitch SW is actuated by the first lever 157. In

response to the actuation of the microswitch SW which detects the end of the backward movement of the cutter driving means 156, the auxiliary driving means 161 is slided leftward to let down the levers 157 and 158 so that the whole construction is set back to its original state. in accordance with the above-described serial operation of the cutting means 150, the upper cutter blade 151 is made to be operated to cut the magnetic strip 11 only when the first lever 157 is rotated counterclockwise by the cutter driving means 156, that is, only under one condition.

The hump forming means 60 is disposed at the feed out side of the cutting means 150 and comprises a couple of hump forming members 61 and 62 one of which has a positively curved surface and the other of which has a negatively curved surface and-a driving means 63 such as a cylinder operated by compressed air for moving at least one of the couple of members 61 and 62 up and down. The couple of hump forming members 61 and 62 are so disposed that there may be a spacing between the both members for providing a hump on the strip 11 running therethrough. As described above, the hump forming means 60 helps the cutting means 150 to continuously cut the magnetic steel strip 11 without stopping the feeding in and feeding out of the strip 1 1 by forming a hump and releasing the strip 11.

The feeding out means 70 for feeding out the pieces of the magnetic steel strip 11 is constructed by a couple of pairs of

pinch rollers

72 and 73 provided in a framework 71 like the feeding in means 30 as described above and a guide plate 74 fixed to the framework 71 therein. Other than the above elements, a belt-conveyor and the like may be employed in the construction. In the case that the feeding speed of the feeding out means 70 is equal to the winding space of the winding means 80, the

pinch rollers

72 and 73 may be ordinary feeding rollers. But in the case that there is difference in speed, e.g., when the winding speed is higher than the feeding out speed, it is required that the

pinch rollers

72 and 73 should be provided with means for enabling the rotation of the rollers at the speed higher than the feeding speed. As for such a means, a ratchet mechanism can be utilized for instance.

On the feed-in side of the cutting means 150, there is provided a guiding means 50 which comprises a pair of guiding plates 51 and 52 and a driving means 53 such as a cylinder operated by compressed air for moving at least one (guide plate 52 in the case of the example shown in FIG. of the guide plates 51 and 52 up and down to close and open the guiding means 50. The guiding means 50 is operated so that by the opening operation thereof it allows the magnetic steel strip 11 running therethrough to hump when the cutter blade 151 is moved down to cut the strip 11, and by the closing operation thereof it feeds the humped strip quickly into the cutting means by straightening the strip just after the cutting means 150 has completed the cutting operation.

The

feed roller

31 and 32 of the feeding in means 30 and the

pinch rollers

72 and 73 of the feeding out means 70 are provided with bevel gears 31b, 3272b, and 73b on the axes of rotation 31a, 32a, 72a and 73a thereof respectively. The bevel gears 31b, 32b, 72b and 73b are in meshing engagement with the bevel gears 31c, 32c, 72c respectively and 73c fixed on the driving shafts 107 and 108 connected through a clutch 110. The shaft 108 and accordingly the shaft 107 are driven by the power source 102 through a gear train consisting of gears 102a, 102b, 1020, a shaft 103, pulleys 10S and 106 around which a belt 104 and the like is running.

The clutch 110 coupling the driving shafts 107 and 108 is operated when the wound core of the type as shown in FIGS. 2 and 3 is wound and when the hoop-shaped magnetic steel strip 11 is all fed out and a new hoop is required to be mounted at the supporting means 20, in order to temporarily stop the feeding in means 30.

The above-mentioned power source 102 is connected to the winding means 80 so as to drive and rotate the same through a shaft 1 11 having a bevel gear l02b at an end thereof and a pulley 112 at the other end thereof and a belt 113 running around the pulley 112. The shaft 111 for driving the continuous winding means 80 is connected with a second metering means 1 15 which meters the length of the strip piece Ma wound by the winding means 80. The second metering means 115 is disposed in relation with the rotation of the spool 81 about the axis of rotation 95 and related with the microswitch SW. which is actuated at the beginning of winding. Thus the second metering means 115 makes it easy to make such a wound core as shown in FIGS. 2 and 3.

The continuous winding means 80 for continuously winding the pieces of magnetic steel strip 11 cut in the prescribed size and fed out from the feeding out means continuously will now be described in detail with reference to a preferred embodiment thereof shown in FIG. 11. A framework 91 is mounted on a base 90 and is provided with a rotatable spool 81 and a plurality of

pulleys

82, 83, 84, 85, 86 and 87. An endless belt 88 is disposed to run around the pulleys 82 through 87 and the spool 81 in the shape to receive the fed out pieces 11a of the magnetic strip 1 l. The rotation of the power source 102 is transmitted to the pulley 83 through a belt 1 13, an intermediate pulley 114, and a belt 115. The transmitted rotation on the pulley 83 is further transmitted to the spool 81 and the

pulleys

82, 84, 85, 86 and 87. Thus, the pieces 1 1a of the magnetic steel strip 11 fed out from the feeding out means and into the winding means are wound into a wound core on the spool 81.

The pulleys and 86 are supported on a pulley carrier 94 which is slided in a slide guide 93 by a tension exerting means 89, so that the

pulleys

85 and 86 exert tension on the endless belt 88. And by the tension exerted on the endless belt 88, the pieces 11a of the of the magnetic steel strip 11 are tightly wound on the spool 81 so that the wound core may be obtained in a good condition and the wound core may be easily removed from the spool 81 by warming it. The spool 81 is mounted on a spool holding member 97 which is slided in a slide guide 96. The spool holding member 97 is slided by an operating means 92 for sliding the member 97 together with the spool 81 mounted thereon, so that the increase in the diameter of the wound core on the spool is compensated. In response to the increase in the diameter of the wound core on the spool, the length of the loop of the endless belt 88 around the core is also increased This increase in the length of the loop is compensated by the move of the tension exerting means 80. That is, by the rightward movement of the tension exerting means 89, a constant tension can be always obtained on the endless belt 88 regardless of the loop size of the endless belt. Thus, the pieces 11a of the magnetic steel strip 11 are wound on the spool in a constant tightness. In order to guide the pieces 11a of magnetic steel into the winding means with certainty, a guide plate 98:: held by a holding spring 98b may be provided between the

pulleys

82 and 83. By this disposition of the guide plate 980 the pieces 11a of the magnetic steel strip 11 fed out of the feeding out means 70 are guided between the guide plate 98a and the endless belt 88 running around the pulley 82 without fail.

A microswitch SW is disposed in relevant to the axis of rotation of the spool 81 so that the position of winding start of the pieces 11a of the magnetic steel may be detected thereby. By the operation of the microswitch SW and the second metering means 115, the clutch 110 is operated or released to temporarily stop or start again the feeding in means 30. Thus, the seam positions in the wound core can be easily made to exist in a limited range and the feeding in means 30 can be easily stopped when the hoop-shaped magnetic steel strip is supplemented.

in the case that the wound core as shown in FIGS. 2 and 3 is made, the microswitch SW disposed in relevant to the axis of rotation of the spool 81 and the second metering means for metering the wound length are effectively utilized.

In other words, in the case of making the wound core as shown in FIGS. 2 and 3, it is necessary to temporarily stop the feeding of the magnetic steel strip 11 by the feeding in means 30 by means of the clutch every time the group of the pieces lie of the magnetic steel is finished winding until the starting position of the winding of the next piece Ella comes to the position in alignment with the starting position of the winding of the first piece in the previous group. And in order to stop the feeding of the magnetic steel strip ll ii, the microswitch SW, is used to operate the clutch illfl. in such a case, the clutch llli) should not be operated just after the microswitch SW is actuated but should be operated after the second metering means M5 meters a prescribed length of the winding. Now the above-described operation will be described with respect to an example. in the case that the internal diameter of the wound core is 200 mm. the thickness of the pieces of the magnetic steel is 0.35 mm. and the number of the pieces in one group of the pieces is 10, the length of the first piece of the magnetic steel strip on the innermost convolution of the wound core is 200 11mm. and that of the last piece of the magnetic steel strip on the outermost convolution is 200-l-(2 X0.3 X) vrmm. and then there is 7 11mm. difference in length between the both. Accordingly, the clutch llllfl should be operated after the spool til is rotated by 7 rrmm. further after the microswitch SW, is actuated in order that the subsequent pieces may be fed into the winding means in the right position where the starting position of winding of the first pieces of the respective groups are in alignment with one another. In the case of the winding between the second and third groups, the second metering means 11115 is used for making the clutch llltl operate after the spool 81 is rotated by 71r 2 mm. after the microswitch SW is actuated. In the case of the winding of the pieces between the third and the fourth groups, the further rotation of the spool should be 71r 3 mm. Thus, the clutch lift is operated after the prescribed length of strip was me tered by the metering means so as to make the initial position of the winding of the respective groups be in a limited range.

The second metering means 115 may not always be disposed on the shaft 111 as shown in H6. ill, but may be for instance disposed in relevant to the pulley d2, 83, 84, $5, $65 and 37 or the endless belt 80. That is, the second metering means llllfi may be disposed at any position where the abovedescribed prescribed length of the strip can be metered.

it is apparent that the continuous winding means d0 driven by the common power source 102 in the embodiment shown in the drawing may be driven by an independent power supply.

Since the apparatus for making the wound core in accordance with the present invention is constructed out of the means as described hereinabove, it becomes possible to make a wound core easily through a series of processes by continuously cutting a hoop-shaped magnetic strip into prescribed length of pieces and winding them up into a convolution.

We claim:

ll. Method of making a wound core comprising the steps of feeding a hoop-shaped magnetic steel strip rotatably supported by a supporting means continuously into a cutting means provided with a cutter which cuts said strip into prescribed length of pieces of magnetic steel, said cutting means being operated in response to the output of a first meterin g means which meters the length of said strip fed into said cutting means, cutting said magnetic steel strip continuously into the prescribed length of pieces of magnetic steel by means of said cutter without stopping the feeding of said strip utilizing a hump of said strip formed by a hump forming means, said hump forming means being provided on the downstream of said cutting means and forming a hump in said magnetic strip before the cutting operation of said cutting means and releas ing said hump formed at the beginning of cutting operation and moving back to form a hump again at the end of cutting operation, feeding the pieces cut out of said magnetic strip into a continuous winding means by means of a feed-out means, and winding said pieces of magnetic steel by said continuous winding means so that the seam positions between the adjacent pieces may be out of alignment with one another.

2. Method of making a wound core as defined in claim 1 wherein the winding speed of said continuous winding means is made slightly higher than the feeding speed of said feed out i llll means so that the seam positions between the pieces of magnetic steel may be out of alignment with one another by the difference in speed.

3. Method of making a wound core as defined in claim 11 wherein said cutter in the cutting means is made to out said strip in the different length so that the difference in length may arrange said pieces in said wound core in the arrangement out of alignment with one another.

3. Apparatus for making a wound core comprising a. a supporting means for rotatably supporting a hoopshaped magnetic steel strip,

b. a feed in means for continuously feeding said magnetic steel strip,

c. a first metering means for metering the length of said magnetic steel strip fed by said feed-in means,

d. a cutting means including a cutter for cutting said magnetic steel strip into the prescribed length in response to the output of said metering means,

e. a compulsory hump forming means disposed at the downstream of said cutting means for forming a prescribed hump in said magnetic steel strip, said compulsory hump forming means forming a prescribed hump normally in the magnetic steel strip before being cut, releasing the hump at the beginning of the cutting operation, and moving back to form a hump again at the end of the cutting operation so that said magnetic steel strip may be continuously cut into the prescribed length of pieces,

f. a feed-out means for feeding the cut pieces of magnetic steel cut by said cutter of the cutting means, and

g. a continuous winding means for winding said pieces of magnetic steel into a core wherein the seam positions between the pieces are out of alignment with one another.

5. Apparatus for making a wound core as defined in claim 4 wherein a common power source is disposed for driving said feed-in means, said feed-out means and said continuous winding means, and a clutch is disposed for connecting the driving shafts of said feed-in means and feed-out means.

ti. Apparatus for making a wound core as defined in claim d wherein two independent power sources are disposed for respectively driving said feed-in means and said feed-out and winding means, and a clutch is disposed for connecting said feed-in means and said feed-out means.

7. Apparatus for making a wound core as defined in claim d wherein said first metering means comprises a metering roller rotating in contact with said magnetic steel strip and a meter of pulse generator type connected with said metering roller.

8. Apparatus for making a wound core as defined in claim t wherein said cutting means comprising a holder for holding said cutter, a supporting member for supporting a guide by which said holder is guided up and down, a cutter driving means for operating said cutter secured to said holder, a first and a second lever interlocking said cutter driving means with said holder in said guide for transmitting the movement of said cutter driving means to said cutter, and an auxiliary driving means for moving said cutter up and down after the cutting operation through said first and second levers.

5". Apparatus for making a wound core as defined in claim 3 wherein said cutter in said cutting means has thickness enough to cut off the magnetic steel strip of the length required to make the seam positions in the wound core be out of alignment with one another.

Ml. Apparatus for making a wound core as defined in claim 4i wherein a steel strip guide means is disposed at the upstream of said cutting means for letting the magnetic steel strip be humped when said cutting means is operated to cut said strip and feeding forward said strip when said cutting means finished cutting operation.

llll. Apparatus for making a wound core as defined in claim 4 wherein said compulsory hump forming means comprises a couple of hump forming members one of which has a positively curved surface and the other of which has a negatively curved surface and a driving means for moving at least said to receive said pieces of magnetic steel to be wound thereon, said belt being made to vary the diameter of the loop thereof around said spool, and a tension exerting means for exerting tension on said endless belt, whereby said endless belt is driven by at least one of said pulleys and said spool is made to rotate towind said pieces of magnetic steel.

l h II t III

Claims

1. Method of making a wound core comprising the steps of feeding a hoop-shaped magnetic steel strip rotatably supported by a supporting means continuously into a cutting means provided with a cutter which cuts said strip into prescribed length of pieces of magnetic steel, said cutting means being operated in response to the output of a first metering means which meters the length of said strip fed into said cutting means, cutting said magnetic steel strip continuously into the prescribed length of pieces of magnetic steel by means of said cutter without stopping the feeding of said strip utilizing a hump of said strip formed by a hump forming means, said hump forming means being provided on the downstream of said cutting means and forming a hump in said magnetic strip before the cutting operation of said cutting means and releasing said hump formed at the beginning of cutting operation and moving back to form a hump again at the end of cutting operation, feeding the pieces cut out of said magnetic strip into a continuous winding means by means of a feed-out means, and winding said pieces of magnetic steel by said continuous winding means so that the seam positions between the adjacent pieces may be out of alignment with one another.

2. Method of making a wound core as defined in claim 1 wherein the winding speed of said continuous winding means is made slightly higher than the feeding speed of said feed out means so that the seam positions between the pieces of magnetic steel may be out of alignment with one another by the difference in speed.

3. Method of making a wound core as defined in claim 1 wherein said cutter in the cutting means is made to cut said strip in the different length so that the difference in length may arraNge said pieces in said wound core in the arrangement out of alignment with one another.

4. Apparatus for making a wound core comprising a. a supporting means for rotatably supporting a hoop-shaped magnetic steel strip, b. a feed in means for continuously feeding said magnetic steel strip, c. a first metering means for metering the length of said magnetic steel strip fed by said feed-in means, d. a cutting means including a cutter for cutting said magnetic steel strip into the prescribed length in response to the output of said metering means, e. a compulsory hump forming means disposed at the downstream of said cutting means for forming a prescribed hump in said magnetic steel strip, e''. said compulsory hump forming means forming a prescribed hump normally in the magnetic steel strip before being cut, releasing the hump at the beginning of the cutting operation, and moving back to form a hump again at the end of the cutting operation so that said magnetic steel strip may be continuously cut into the prescribed length of pieces, f. a feed-out means for feeding the cut pieces of magnetic steel cut by said cutter of the cutting means, and g. a continuous winding means for winding said pieces of magnetic steel into a core wherein the seam positions between the pieces are out of alignment with one another.

6. Apparatus for making a wound core as defined in claim 4 wherein two independent power sources are disposed for respectively driving said feed-in means and said feed-out and winding means, and a clutch is disposed for connecting said feed-in means and said feed-out means.

7. Apparatus for making a wound core as defined in claim 4 wherein said first metering means comprises a metering roller rotating in contact with said magnetic steel strip and a meter of pulse generator type connected with said metering roller.

8. Apparatus for making a wound core as defined in claim 4 wherein said cutting means comprising a holder for holding said cutter, a supporting member for supporting a guide by which said holder is guided up and down, a cutter driving means for operating said cutter secured to said holder, a first and a second lever interlocking said cutter driving means with said holder in said guide for transmitting the movement of said cutter driving means to said cutter, and an auxiliary driving means for moving said cutter up and down after the cutting operation through said first and second levers.

9. Apparatus for making a wound core as defined in claim 4 wherein said cutter in said cutting means has thickness enough to cut off the magnetic steel strip of the length required to make the seam positions in the wound core be out of alignment with one another.

10. Apparatus for making a wound core as defined in claim 4 wherein a steel strip guide means is disposed at the upstream of said cutting means for letting the magnetic steel strip be humped when said cutting means is operated to cut said strip and feeding forward said strip when said cutting means finished cutting operation.

11. Apparatus for making a wound core as defined in claim 4 wherein said compulsory hump forming means comprises a couple of hump forming members one of which has a positively curved surface and the other of which has a negatively curved surface and a driving means for moving at least said hump forming member having a positively curved surface up and down.

12. Apparatus for making a wound core as defined in claim 4 wherein said continuous winding means comprises a rotatable and movable spool, a plurality of pulleys disposed around said spool, an endless belt running around said pulleys and along almost all the periphery of said spool except the portion to reCeive said pieces of magnetic steel to be wound thereon, said belt being made to vary the diameter of the loop thereof around said spool, and a tension exerting means for exerting tension on said endless belt, whereby said endless belt is driven by at least one of said pulleys and said spool is made to rotate to wind said pieces of magnetic steel.