DE69502635T2 - Coil winding machine - Google Patents

Description

Field of the invention

This invention relates to a machine for winding a coil such as a flyback transformer or the like, and more particularly to a mechanism that winds an insulating film on a coil.

Background of the invention

Some coils used in flyback transformers or the like have layers of coil windings and an insulating film alternately superimposed on one another. In other words, an insulating film is wound over a coil wound on a coil core, a coil is wound over the film, and the insulating film is then wound on the coil.

A method of winding a film on such a spool is disclosed, for example, in Tokkai Hei 5-101961 published by the Japanese Patent Office in 1993.

In this method, an insulating film is gripped by two gripping devices known as a front nip and a rear nip. An end of the insulating film wound on a reel is first gripped by the front nip, the film is pulled off the reel, and the front end of the film is then heated to weld it to the reel. Next, the front nip releases the film, returns to the vicinity of a cutting position, and the film is gripped near the cutting position by the rear nip and the front nip. After the film is cut by a cutting device between the rear nip and the front nip, a spool core is rotated to wind the film onto the spool core. In this process, the rear end of the film is gripped by the rear nip and a predetermined tension is applied to the film so that it is wound onto the spool core without any slack.

In this winding process, since the film is cut after the leading end is attached to the spool core, the winding length of the film is determined by the distance between the cutter and the spool core. When the position of the cutter is fixed and it is desired to change the winding length, the position of the spool core must be changed.

From the standpoint of efficiency, it is preferable that the film is cut during the spool winding process and then the film is wound only after the spool winding process. However, in the above-mentioned winding method, the film is cut after the leading end of the film is attached to the spool core, so that it cannot be cut first.

Summary of the invention

It is therefore an object of this invention to modify the film length as desired without changing the spool exposure.

It is a further object of this invention to perform film cutting in parallel with coil winding.

To achieve the above object, this invention provides a coil winding machine comprising a coil winding mechanism for winding a coil on a rotating spool core and a film winding mechanism for winding an insulating film on the coil.

The film winding mechanism comprises a roller for feeding a film, a main nip for gripping the leading end of the film, a mechanism for moving the main nip in a predetermined direction, a tension nip for gripping the film drawn through the main nip at a predetermined position, a cutter for cutting the film on the roller side of the nip, a mechanism for moving the tension nip having gripped the film in the predetermined direction together with the Main nip and a mechanism for returning the nip that has released the film to the predetermined position.

Preferably, the clamping nip moving mechanism comprises a mechanism for moving the main nip and a guide for guiding the clamping nip so that it is free to be displaced in the predetermined direction, and the return mechanism comprises a mechanism for urging the clamping nip to the predetermined position.

The pressing mechanism preferably comprises an air cylinder and a mechanism for supplying air to the air cylinder.

Alternatively, the pressing mechanism comprises a belt passing over two pulleys arranged in a vertical direction and a counterweight connected to the belt, and the clamping gap is connected to this belt.

The guide is preferably provided with a mechanism for adjusting a guide angle.

It is also preferred that the spun winding machine further comprises a mechanism for moving the spool core.

The details as well as other features and advantages of this invention are set forth in the remainder of the specification and are illustrated in the accompanying drawings.

Short description of the drawings

Figure 1 shows a perspective view of a spun winding machine according to this invention.

Figure 2 shows a perspective view of a cutting device according to this invention.

Figure 3 shows a side view of a film winding mechanism according to this invention.

Figure 4 shows a side view of the film winding mechanism, viewed from a direction perpendicular to that of Figure 3.

Figure 5 is similar to Figure 4, but represents a different embodiment of the invention.

Description of the preferred embodiments

An automatic spun winding machine, shown in Figure 1 of the drawings, winds a coil and a film 7 on a spool core 1.

This automatic coil winding machine comprises a spindle 3 supported by a moving mechanism 4, a nozzle 5 for feeding out wire and a conveyor 6 for transporting the coil core 1, these components being mounted on a base 12.

The automatic coil winding device fixes the coil core 1, which has been transported on the base 12 by the conveyor 6, on the spindle 3 when the spindle 3 is moved by the moving mechanism 4. Subsequently, the end of the wire fed through the nozzle 5 is fixed to a predetermined portion of the coil core 1, the spindle 3 is rotated and the wire is thereby wound on the coil core 1.

The insulating film 7 is wound on the spool core 1 on each spool layer and for this purpose the spool winding machine is also provided with a film winding mechanism. This film winding mechanism comprises a roller 8 for feeding the film 7, a film punch 9 which forms a groove in the film 7 fed out from the roller 8 and an embosser 10 which imprints a wavy pattern on the film 7, all of these components being mounted on the base 12.

A main nip 13 and a tension nip 14 which grip the film 7 and a cutting device 15 are installed below the embossing device 10.

The main nip 13 comprises a pair of parts which open and close when driven by an air cylinder 20. The main nip 13 is supported by an arm 17 which threads onto a vertically oriented spindle 16 mounted on the base 12 and is moved up or down by the operation of a motor 18 connected to the spindle 16.

The main clamping gap 13 effectively moves parallel to the spindle 3 within predetermined limits according to the drive power of an air cylinder 19 which is located between the clamping gap 13 and the arm 17.

The clamping gap 14, which is similar to the main clamping gap 13 and projects downwards at an angle from the base 12, is attached to a bracket 32 which is freely moved to move up and down in a guide 22 as shown in Figures 3 and 4. This bracket 32 is connected to an air cylinder 21. The air cylinder 21 is compressed by internal compressed air and when in its most compressed position, the clamping gap 14 is held in its starting position directly below the cutter 15 as shown by the solid line in Figure 3.

The compressed air supplies 23, i.e. low pressure and high pressure, are connected to the air cylinder 21. The clamping gap 14 is provided with an air cylinder 24 which opens or closes it and grips the film 7 on the side opposite to the main clamping gap 13. The main clamping gap 13 and the clamping gap 14 are of such dimensions that their front ends cannot interfere with each other, thereby allowing the main clamping gap to move upward from the clamping gap 14.

The guide 22 is formed of a one-piece structure with a guide platform 41 freely supported to rotate on the base 12 via a pivot 40. An adjustment screw 42 screws into the upper end of the guide platform 41 to adjust the inclination of the guide 22. This front end passes through the guide platform 41 so as to come into contact with the base 12. By rotating this adjustment screw 42, the guide platform 41 is caused to tilt forward or backward through a small angle from the upright position about the pivot 40.

The cutting device 15 is located directly below the embossing device 10 and cuts the film 7 by gripping it from both sides due to the driving force of the two air cylinders 25.

The cutter 15 comprises a knife 15A which cuts the film 7 and a press 15B which is urged by a spring 34 so as to press the film 7 above the knife 15A as shown in Figure 2. These components are effectively installed parallel to the opening and closing parts of the tension nip 14 as shown in Figure 4 so as to cut the film 7 obliquely to a horizontal direction. Furthermore, when the cutter 15 is open, it has an opening sufficient to allow the main nip 13 to pass through it.

The film winding mechanism comprises a welding head 26 for welding the film 7 to the spool core 1 and a film press 27 for pressing the film 7 onto the spool core 1, these components being installed in the lower part of the base 12. By means of this structure, the welding head 26 comes into contact with a part of the film 7 and heats it while the front or rear end of the film 7 is pressed onto the outer periphery of the spool core 1 by means of the press 27, and the film 7 is thereby welded to the spool core 1. The welding head 26 and the film press 27 are supported on the base 12 via drive mechanisms required to perform these operations.

In this reel winding machine, the mechanical processing of the film by the film punch 9 and the embossing device 10 and the cutting of the film 7 by the cutting device 15 are carried out simultaneously with the winding of the reel.

To cut the film 7, the main nip 13 is first raised by a motor 18 so that it is located directly below the embosser 10, and the front end of the film 7 is gripped. As it moves upward, the cutter 15 is held open and the main nip 13 reaches the gripping position above the cutter 15. Due to the action of the air cylinder 20, the film 7 is then gripped and the main nip 13 is moved to a predetermined position by by activating the motor 18 again. This causes the film 7 to be released from the roll 8.

When the main nip 13 has reached the predetermined position, the tension nip 14 grips the film 7 directly below the cutter 15 due to the action of the air cylinder 24 and the cutter 15 cuts the film 7 due to the action of the air cylinder 25.

The mechanical processing of the film 7 by the film punch 9 and the embosser 10 is carried out before the film 7 is retracted through the main nip 13, but the film punch 9 and the embosser 10 can be operated during film retraction by temporarily stopping the main nip 13. In this way, any desired part of the film 7 can be processed. Similarly, the cutting length of the film 7 can be adjusted by changing the stopping position of the main nip 13.

The front and rear ends of the cut film 7 are gripped by the main nip 13 and the tension nip 14, respectively, and the entire film 7 is moved when the main nip 13 is moved by the motor 18. Air of low pressure is then supplied to the air cylinder 21 from the compressed air supply mechanism 23, and the tension nip 14 is displaced against the compressive force of the air cylinder 21 when a predetermined low tension is applied to the film 7. The pressure supplied to the air cylinder 21 by the compressed air supply mechanism 23 is maintained constant, and thus the tension in the film 7 is also maintained constant regardless of the displacement position.

The main nip 13 stops moving downward when the leading end of the film 7 reaches one side of the spool core 1.

All the above operations are carried out simultaneously with the winding of the coil on the coil core 1.

After one layer of the coil has been wound, the coil core 1 is moved sideways on the spindle 3 due to the action of the drive mechanism 4 and is brought into contact from one side with the front end of the film 7 supported by the main nip 13. The film press 27 then presses the film 7 onto the spool core 1, the welding head 26 comes into contact with the film 7 and the contact part is heated so that the film 7 is welded onto the outer periphery of the spool core 1.

Next, the main nip 13 is released, the spindle 3 is rotated, and the film 7, the front end of which is attached to the spool core 1, is wound onto the spool core 1. The air cylinder 21 of the tension nip 14, which grips the rear end of the film 7, is still kept under low pressure. This is to prevent excessive tension from acting on the film 7 immediately after welding. The air cylinder 21 is then changed to a high pressure so as to increase the tension in the film 7 once the winding has progressed to a certain extent, and the film 7 can therefore be wound onto the spool core 1 without any slack.

The clamping gap 14 descends in the guide 22 when it grips the rear end of the film 7, whereby the film 7 can be wound accurately on the same position of the spool core 1 up to its rear end without any displacement.

The inclination of the guide 22 can be adjusted by adjusting the adjusting screw 42. When the adjusting screw 42 is rotated, the position at which the clamping gap 14 grips the film 7 is changed. The clamping gap 14 moves guided by the guide 22, however, when the base end of the guide 22 is located near the hinge 40, its position effectively becomes constant regardless of the rotation of the adjusting screw 42. Therefore, rotating the adjusting screw 42 slightly changes the angle between the film 7 and the axis of rotation of the spool core 3. Consequently, if the film 7 tends to incline to one side of the spool core 1 as winding progresses, the sideways displacement of the film 7 wound on the spool core 1 can be easily corrected by rotating the adjusting screw 42.

After the winding of the film 7 is completed, the clamping nip 14 is released, the rear end of the film 7 is pressed against the spool core 1 by driving the film press 27 again, and the rear end of the film 7 is welded to the outer periphery of the spool core 1 by the welding head 26. At the same time, the clamping nip 14 which has released the film 7 is pressed upward by the air cylinder 21 under high pressure and is therefore quickly raised to its starting position directly below the cutter 15.

This completes the winding of the film 7. The spool core 1 then moves again to the spool winding position and the next layer of a spool is wound onto the film 7.

Therefore, cutting and machining of the film 7 are carried out simultaneously with the spool winding process, and since only one winding is carried out during the film winding process, less time is required for winding the film 7 and the spool can be manufactured with high efficiency.

The coil diameter increases as the coil winding progresses, however, the welding position of the film 7 is kept constant by varying the position of the spindle 3 by means of the shifting mechanism 4. The welding position of the film 7 can also be kept constant when coil cores of a different outer diameter are used.

Figure 5 illustrates another embodiment of this invention relating to means used to press the clamping nip 14. According to this embodiment, a belt 30 and a counterweight 33 are used instead of the air cylinder 21.

The belt 30 passes around an upper and a lower pulley 31, the clamping gap 14 being attached to the belt 30 via the carrier 32 guided by the guide rail 22. The counterweight 33, which is slightly heavier than the combined weight of the clamping gap 14 and the carrier 32, is attached to the belt 30 on the opposite side of the clamping gap 14. The position under which the counterweight 33 is attached is selected so that the lowest Position to which the counterweight 33 drops is the film gripping position of the clamping gap 14.

According to this embodiment, when the cut film 7 descends while being gripped by the main nip 13, the counterweight 33 resists the displacement of the tension nip 14 following the main nip 13, and a predetermined tension is thereby applied to the film 7. Furthermore, the tension nip 14 which has released the film 7 is automatically pulled up to the start position directly below the cutter 15 due to the balancing effect of the counterweight 33. According to this embodiment, the film winding mechanism can be constructed more simply and economically than the mechanism according to the first embodiment where the tension nip 14 is pressed by the air cylinder 21 and the compressed air supply mechanism 23.

In any of the above-mentioned embodiments, the tension nip 14 does not have its own moving means. When the tension nip 14 grips the film 7, it follows the main nip 13 guided by the guide 22, and when it has released the film 7, it is returned to a predetermined position by a pushing means. The tension nip 14, however, may also be provided with a shifting mechanism of the same type as that used for the skin nip 13, and these two shifting mechanisms are designed to operate synchronously.

The embodiments of the invention in which exclusive property or privilege is claimed are defined as follows:

Claims (6)

1. Coil winding machine comprising a coil winding mechanism for winding a coil on a rotating coil core (1) and a film winding mechanism for winding an insulating film (7) on the coil, characterized in that the film winding mechanism comprises: a roller (8) for feeding a film (7), a main clamping gap (13) for gripping the front end of the film (7), a device (18) for moving the main clamping gap (13) in a predetermined direction, a clamping nip (14) for gripping the film (7) pulled through the main nip (13) at a predetermined position, a cutting device (15) for cutting the film (7) on the side of the roll of the clamping gap (14), a device for moving the clamping nip (14) which has gripped the film (7) in the predetermined direction together with the main nip (13) and Means for returning the clamping gap (14) which has released the film (7) to the predetermined position. 2. Coil winding machine according to claim 1, wherein the clamping gap moving device comprises a device (18) for moving the main clamping gap (13) and a guide (22) for guiding the clamping gap (14) such that it is free to be displaced in the predetermined direction, and wherein the return means comprises means for pressing the clamping gap (14) toward the predetermined position. 3. Spun winding machine according to claim 2, wherein the pressing device comprises an air cylinder (21) and a mechanism (23) for supplying air to the air cylinder (21). 4. Coil winding machine according to claim 2, wherein the pressing device comprises a belt (30) which passes over two pulleys (31) arranged in a vertical direction and a counterweight (33) connected to the belt (30), the tensioning nip (14) being connected to this belt (30). 5. Coil winding machine according to claim 2, wherein the guide (22) is provided with a mechanism (42) for adjusting a guide angle. 6. Spun winding machine according to claim 1, wherein the machine further comprises means (4) for moving the spool core (1).