CA2112774C - Saddle coil for cathode ray tube deflection systems - Google Patents

Abstract

A process and a device for producing self-supporting saddle coils (96), where first, a winding receiver (10), which has a base (11) and a cutout (13), is produced to form saddle coils (46). Segments (12) can be attached to the inside contour of the cutout (13). These segments (12) are spaced with respect to each other. These spaces, also called slots (14), serve to receive wires running in the Z-direction. The constructed length of the segments (12) is such, that their ends extend beyond the base (11), thus forming the chambers (16.u, 16.o) between the edges (15.o, 15.u) and the ends of segments (12) that curve away from the centerline. This winding receiver (10) is wrapped by a winding device (21), which wraps the wire in the slots (14) and the chambers (16.u, 16.o). When the winding pass of saddle coil (46) is formed, the wrapping wire (32), covered with thermoplastic material, is heated so that the windings of the wrapping wire (32) are bonded to each other, after cooling. The segments (12) are then removed from the cutout (13) and the finish-baked saddle coil (46) can be pulled out of the cutout (13).

Description

_1_ Technical Field The invention concerns a process for producing self-supporting saddle coils for cathode ray tubes, and a device for producing such saddle coils.
Back__c~round of the Invention Saddle coils for deflecting electron beams in cathode ray tubes have been known for a long time in the state of the art, so that an explanation of the construction and function of such saddle coils can be kept to a minimum.
Saddle coil installations for cathode ray tubes are usually shaped like trumpets, which are formed by combining a pair of saddle coils, such as are the subject of the invention. The inside contour of such a saddle coil arrangement, and therefor each of the two saddle coils, conforms to the outside contour of the cathode ray tube in the area where the saddle coil arrangement comprising the two saddle coils will subsequently be connected to the tube. In addition to this configuration, as indicated in DE 2,807,978 the outside contour of the first saddle coil arrangement that rests directly against 'the picture tube, can be surrounded by another saddle coil arrangement that also comprises two half coils.
Each of the saddle coils is farmed by a uniform winding comprising several layers of wire. In a first approximation, the course of this winding is formed so that at least two strands of wire run in the Z-direction of the picture tube, where front and'rear ends are connected with each other by a so-called winding head. Each of these winding heads is essentially semicircular and extends transversely to the direction of the wires.
The above described configuration of saddle coils is no longer suitable for the deflection accuracy required today, particularly for in-line tubes. For this reason, the saddle coils needed for these purposes are equipped with a number of wire strands that extend in the Z-direction. The arrangement of these wire strands with symmetrical angles can be chosen, so that their planes run through a common center point in a transverse cut through the centerline of the tube. Some saddle coils are also known, in which the planes of the wire strands extending in the Z-direction have no common center point, but are parallel or at an angle to each other. The course of the wires in the latter sense is shown in figure 4 of EP 0,264,807, for example.
When forming a deflection field, it may also be necessary for the length of at least one of the wires on one side of the saddle coil to be different from the length of the other wires on that side, but all wires on one side have the same length as the wires that have symmetrical angles on the other side of the coil. As particularly pointed out in DE

3,920,699, it may be necessary, for reasons of deflection correction, to omit the lateral symmetry in the slot lengths.
There axe essentially two processes with which the coils that correspond to the above described windings can be produced.
According to one of the production processes, the saddle coils are formed so that one or more enamelled copper wires, which are additionally covered with a thermoplastic material, are wound in a gap. This gap is formed between two winding forms, where the outside contour of one of:the winding forms essentially corresponds to the outside contour of the tube in the area where the coil will subsequently be attached to the tube, and the inside contour of the other (external) winding form corresponds approximately to the outside contour of the finished saddle coil.

_ 3 _ Such an arrangement is shown in figure 25 of the Phillips tec writing, rev.3, no. 6/7, page 166, where the outer winding form has been omitted. If the arrangement with the outer winding form shown therein is kept at a distance, the wrapping wire can be placed in the gap by means of a suitable winding nozzle that follows the gap path along the edge, since the gap reaches to the edge area of both form parts. A fixed winding nozzle is normally used for that purpose, in front of which the rotating form passes in accordance with its gap path. However, in order for the wrapping wire to assume its defined position in the gap or on the outside contour of the inner winding form, the latter must glide along the inside contour of the outer winding form until it reaches its final position. During the winding, pins having the function of guide points are inserted in the gap between the two forms from the inside to outside, so that separated wire strands can be formed by means of this manufacturing process. After the gap has been filled, in other words the saddle coil has been wound in the gap, the wire is heated until its thermoplastic jacket softens. When it cools, the adjacent windings bond together so that the saddle coil can be removed from the device as a self-supporting coil.
With this manufacturing process it is easy to see that the gliding of the wrapping wire to the predetermined position is unusually critical. Any improper position of the wrapping wire leads to a different filling and gliding characteristic of the wire on the form, because of the original inclination of the thermoplastic jacket on the wire under the effect of humidity, so that it can no longer assume its predetermined position in the gap. Other parameters that impair the reproducibility of saddle coils under this method, are the surface condition of the winding forms and variations in the ware diameter and the wire pull. Since pins are used with this method to form the wire strands, and the wire is placed against these pins, there _ 4 _ are small bulges in the wire path, which diminish the quality of the deflection field created by these saddle coils. Another disadvantage of saddle coils produced by this method is that only the wire strands facing directly against the pins can be wound with the desired accuracy, but not those facing away from the pins. Because the wrapping wire is wound into a saddle coil in the gap formed by the two winding forms, and because pins are inserted in the gap between the two winding forms from the inside to the outside, this winding method is unable to form strand paths that can be simply created with the other manufacturing process, further described below. As shown in figure 11, these strand paths, which cannot be formed with the baked coil technique, are those that have a curved strand path SVI with respect to symmetry plane S between the upper and the Iower winding head WKO, WKU, or strand paths SV2, which curve away from the symmetry plane S in area B, between the upper and the lower winding head WICK. ~U' According to the other manufacturing process, the saddle coils are formed on so-called coil carriers, which have most of the shape of the subsequent saddle coil. The saddle coil is formed on the surface of these coil bodies by means of corresponding winding installations. Publication EP
0,264,807 describes the winding process of such a coil body. This publication (particularly its US priority indication = US 4,946,112) shows that the inside contour of the coil body has slots for forming wire strands in the Z-direction. The winding heads are in semicircular chambers located on the outside contour of the coil body. Slots are formed in the outside walls of the chambers. The slots 'end in the chambers at these slots.
The presence of slots and chambers in the above named manufacturing process permits the production of saddle coils with extraordinarily accurate wrapping wire positions.

The great freedom of form of saddle coils produced with this technique was pointed out earlier in connection with figure 11. However, the fact that coil carriers are required with this manufacturing process is a disadvantage.
This is not only because the coil carrier makes the manufacture and the recyclability of such saddle coils more expensive, but rather because, in contrast to baked coils, with this type of saddle coil formation it is not possible to connect a ferrite core or another saddle coil arrangement l0 (see D8 2,807,978) directly, and without separation, to the first pair of saddle coils on the picture tube. This forced placement of the coil carrier between the windings and the ferrite core, or the other pair of coils, leads to the fact that saddle coils with coil carriers have lower deflection sensitivity, as compared to baked coils.
Summary of the Invention For that reason, the invention has the task of presenting a manufacturing process arid a device for forming saddle coils, according to which saddle coils can be formed, which avoid the disadvantages of the known saddle coils, and encompass their advantages, In view of the foregoing, in one aspect of the invention, there is provided method for manufacturing a self-supporting saddle coil, characterised by the following steps given in i~he temporal sequence of their application:
(1) constructing a non-disposable winding receiver, in that a recess, which has the form of a trumpet halved along its center line and which is formed on one side of a base member, which forms one part of the winding receiver, is 3o connected on its inner contour to segments, wherein the segments conneci:ed to the base member form slots and chambers for receiving wire strands and coil winding heads, (2) winding a coil shape predetermined by the slots and chambers by means of a wrapping wire covered with thermoplastic material, wherein a winding nozzle, from which the wrapping wire runs out, is located directly opposite regions of the slots and chambers in which the wrapping wire is inserted specifically into a slot or chamber, (3) heatfng the wrapping wire beyond the softening point of the thermoplastic material, (4) allowing the wrapping wire to cool, (5) removing the cooled and hence bonded wrapping wire from the winding receiver, to which end the shape possessed by the winding receiver during the winding is cancelled beforehand by removal of the segments from the base member.
The steps in this process permit the production of self-supporting saddle coils with great freedom of form and with extraordinary precision and speed. It is particularly possible with the invention to form self-supporting saddle coils, whose strands - like the saddle coils built on break-away coil carriers in figure ii - are curved, or which curve away from the plane of symmetry.
a further advantageous development of the process is that wires with very uniform cross-sections are formed if a mold is placed on the surface of the winding receiver, either after step 2 or 3, until the saddle coil cools and bonds, which presses the wires into the slots because of its surface structure. in addition, very uniform heating of the coil wound on the winding receiver can be achieved, if the ends of the wrapping wire are connected to a source of electric power, to heat the wrapping wire.
In a second aspect of the invention, there is provided a device for producing a self-supporting saddle coil for, the apparatus comprising: a winding receiver, on an outside and inside contour of which the saddle coil is - 6a -formed, the winding receiver comprising: a) a base whose side has a cutout in a form of half a trumpet cut through its centerline; b) segments, which are connected to and are removable from the inside contour of the cutout, and which, when connected to the base, form slats and chambers for picking up wire strands and winding heads; a winding device having a winding nozzle for forming the saddle coil by locating the winding nozzle, as well as a wrapping wire having a thermoplastic jacket emanating from the winding nozzle, directly opposite, an area of the winding receiver, on which the Wrapping wire is laid in the slots to form the wire strands, and in the chambers to form the winding heads, and a device for heating the thermoplastic jacket of the wrapping wire.
The invention has the advantage that no break-away coil carriers are required to form saddle coils with a high degree of accuracy in the placement of the individual wires if, in addition, the winding receiver, on the outside and inside contour of which the saddle coil is formed, a base is used, whose side has a cutout in the form of a trumpet cut along its centerline, and forms segments, Which can be removed from the inside contour of the cutout, and which form chambers and slots to receive the wire strands and the winding heads when connected to the base. Rather, if the saddle coil is wound and baked on the winding receiver, the form used for winding can be lifted from the base to remove the saddle coil, by loosening and removing the segments from the inside contour of the cutout.
If the segments are divided into two segment 3o groups, Where one group of segments can be loosely connected to the cutout contour with the larger diameter, and the other to the smaller diameter, all the segments of a group can be separated from the base by pulling parallel to the direction of the axis. Tt is of particularly advantage when a corresponding tool is used to remove or insert the segments of a group. A particularly high degree of precision is achieved for the wires that run in the slots formed by the segments, if a mold can be inserted into the cutout connected to the segments, whose surfaces have ribs that press the wires against the contour of the cutout in the base. If the upper, the lower or both edges of the base have steps in the cutout area, it is easy to vary the length of the wires in the slots.
Brief Description of the Drawings Figure 1 is a winding receiver in the unmounted condition, Figure 2 is a winding receiver in the mounted condition, Figure3 is a detail drawing of a section, Figure 4 is a side view of a winding device, Figure 5 is a top view of a winding device, Figure 6 is a side view of a winding receiver, , Figure 7 is a top view of a winding receiver, Figure8 is another depiction of figure 6, Figure 9 is a side view of a wrapped winding receiver, Figure 10 is another depiction of figure 1, and Figure 11 is a tap view of a saddle coil wound on a break-a way coil carrier.

Best Mode for Carrying Out the Invention Figure 1 shows the components of a winding receiver 10 in the unmounted condition. These components are the base 11 and the segments 12. The base has a cutout 13 on the side facing the viewer, which has the shape of a trumpet cut along its centerline. The segments in figure 1 have been _8_ divided into two groups of segments 12.1, 12.2, with one group of segments 12.1 located above the larger diameter of cutout 13, and the other group of segments 12.2 located under the smaller diameter of cutout 13. The shape of these segments 12.1, 12.2 is adapted to the contour of cutout 13, so that the segments 12.1, 12.2 can be inserted into the cutout 13 in the direction of the arrows, and rest against the contour of cutout 13 in the inserted condition. Such a situation, in which the segments 12.1, 12.2 have been inserted into cutout 13, is shown in figure 2. It can be clearly recognized that the segments 12.1, 12.2 are arranged next to and at a distance from each other on the inside contour of cutout 13, so 'that slots 14 are formed between two adjacent segments 12.1, 12.2 of each segment group, together with the jacket contour of the cutout. The slots 14, which are formed by segment group 12.1, are flush with the slots 14 formed by segment group 12.2, so that slots that pass through are formed on the inside contour of cutout 13. The length of segments 12.1, 12.2 is such that, when inserted into cutout 13, they protrude above and below the edges 15.0 15. u. Since the ends of segments 12.1, 12.2 protruding from cutout 13 also curve away from the centerline, the ends, together with edges 15.0, 15.u of the base 11, form the chambers lG.o and 16. u.
The winding receiver 10 shown in figure 2, or the components forming it (base 11 and segments 12.1, 12.2) are only connected to each other to form a saddle coil. After the saddle coil has been formed on the winding receiver 10, the segments 12.1, 12.2 can be separated from the base 11 and the saddle coil can be lifted from the base 11.
To ensure the solid but always removable connection between the segments 12 and base 11, figure 3 shows a detail section which illustrates how the segments 12 are connected to the base 1l during the winding of the saddle coil. To that effect. hooks 17 are placed on the side of segments 12 facing the base 11 contour, which protrude into bag holes 18 in base 11 when it is joined to segment 12, where their position is fixed in base 11 by at least one movable pin 19.
It should also be pointed out that the attachment of segments 12 is not limited to the type illustrated in figure 3. Rather any type of attachment of segments 12 to base 11 can be chosen, which permit solid, but removable, attachment of segments 12 to the base 11 solidly, but removable.
Nor is it necessary to divide the segments 12 into groups 12.1 and 12.2, as shown in figure 1, for example. In another configuration example, the segments 12 can also be made continuous, in other words in one piece. In that instance however, when removing or connecting the segments 12 from or to the base 11, it is necessary to move them in the direction of the centerline, because their ends curve away from the centerline.
To form the saddle coil, the winding receiver 10 is connected to the holding arm 20 of a winding device 21, shown in a side view in figure 4. A stud 23 is located on a base plate 22, whose upper end is connected to the holding arm 20 for winding receiver 10. An installation is located next to it on base plate 22, which can be moved successively in three vertical planes. This installation has a pillow block 24 for a horizontal rod 25, whose other end is located in a sled 26. The sled 26 can slide along another horizontal rod 27, which is placed at a right angle to rod 25. Rod 27 is connected to base plate 22 by two pillow bioeks 28. A carrier 29 slides along rod 25 and contains 'another vertical rod 30: A holder 31 slides along this rod 30. The holder 31 has a channel 33 (shown by dashes) for the wrapping wire 32, one end of which has an intake nozzle 34, and its other end has the horizontal wrapping nozzle 35.
A discharge nozzle 36 is attached to the free end of wrapping nozzle 35. The intake and discharge nozzles correspond to conventional nozzles used normally.

~:1:~2'~°~~

The holding arm 20 with the winding receiver 10 can rotate around the longitudinal axis of stud 23. The sled 26, and with it rod 25, can move along rod 27, thus vertically to the drawing plane. The carrier 29 can move along rod 25 in the direction of the double arrow 37. The holder 31 can move along rod 30 in the direction of double arrow 38. The three mentioned movements are vertical to each other and the discharge nozzle 36 can therefore be brought to any point in the space encompassed by the moving planes.
For better viewing, the necessary drive installations for the mentioned movements have not been illustrated in the schematic representation of the device for winding saddle coils. In the same way, only a short piece of wrapping wire 32 is shown with intake nozzle 34 and discharge nozzle 36.
Nor is a discharge device for wrapping wire 32 shown, also for better viewing.
Figure 5 is a top view of the installation for winding the saddle coils in figure 4. This illustration clearly shows the possible movement of sled 26 along rod 27, which is indicated by double arrow 39. Also visible is that pillow block 24 extends across the full width of base plate 22, and has a take-up for the end of rod 25 in the area of the opposing rod 27. The movement of holding arm 20 and winding receiver ZO around the longitudinal axis of stud 23 is indicated by the curved double arrow 40.
The winding process is described below. The corres-ponding figures only illustrate the winding. receiver 10 with its slots 14 and chambers 16.0, 16.u for taking up wrapping wire 32, so that the winding process can be clearly depicted.
Figure 6 depicts the winding receiver 10 in a side view.
The figure clearly shows that the slots 14 and chambers 16.0, 16.u are formed by the segments 12 inserted into the cutout 13 of base 11. The wrapping nozzle 35 for winding the saddle coal is in the starting position a. In accord-ance with the indicated movement arrows, the wrapping nozzle 35 moves from this position downward, then under the lower edge formed by the ends of segments 12, subsequently upward in front of the slot 14 to be wrapped. The wrapping nozzle 35 then moves further upward and to the right, to the position indicated by b above the upper edge formed by the ends of segments 12. From there follows a movement to the right and then downwards to the position indicated by c.
Figure 7a is a top view of winding receiver 10, and the wrapping nozzle 35 is shown in position c. The winding receiver 10 now makes a 180° clockwise turn (arrow 41), while the wrapping wire 32 is laid in the upper chamber 16Ø At the end of this process, the position shown in figure 7c is reached. Figure 7b illustrates the winding receiver 10 with a partially broken edge, to show the wrapping wires 32 in the chamber 16.o below. This figure also illustrates that the planes of slots 14, and therefore the planes of the subsequent wires of saddle coil, do not pass through the center point 42 of winding receiver 10.
Subsequently the wrapping nozzle 35 moves upward, in other words away from the drawing plane, and the winding receiver 10 makes a 180° turn in the counterclockwise direction (arrow 43). At the same time the wrapping nozzle 35 moves left until it reaches position d in figure 7d.
In figure 8, position d of the wrapping nozzle 35 and winding receiver 10 in figure 7d is again shown in a side view, The wrapping nozzle 35 now moves downward until it reaches position e. From here it moves left and then upward until it laterally reaches the lower chamber 16.u, formed by the protruding segments 12 at the lower edge of the winding receiver 10. In this position, winding receiver 10 turns 180° counterclockwise and lays the wrapping wire 32 into the above cited chamber 16. u. Subsequently the wrapping nozzle 35 returns to position a and the coil body rotates back 180°

-' _ 12 clockwise, while the wrapping nozzle 35 simultaneously moves upward and reaches position g shown by dashes. This position corresponds approximately to the starting position of the winding process, and the next winding takes place in the same manner. When the first slot 14 is full, wrapping nozzle 35 moves from its starting position to the next slot and performs the winding process as described. The winding process depicted in connection with figures 6 to 8 is not limited to a winding installation according to figures 4 and 5. Rather any other winding installation can be used to perform the wrapping steps, if it is suited to lay wrapping wire 32 into the provided slots 14 and chambers 16, on both sides of the contours of a winding receiver 10. The concept of "on both sides of a contour" means a winding in the present sense. in which a part of the winding pass is formed on the outside of a contour (in this instance the wires laid in chambers 16) and another part of the winding pass is formed on the inside of the contour (in this instance the wires laid in slots 14).
A fully wound winding receiver 10 is shown in figure 9.
This figure 9 clearly illustrates that a part of the winding pass building the saddle coil is formed on the outside of segments 12, in other words at the upper and lower chamber 16.0, 16. u. In this illustration the wires, which follow the slots 14 formed by the segments 12 on the inside of base 11, are indicated by hash-marks. Deviating from the illustration until now, the underside of base 11 is formed in steps. This stepped construction on the underside 15.u of base 11, permits the selection of different lengths of the wire strands which run in the slots 14 on one side: of the coil, which leads to a flat (not crimped) winding head which is advantageous in many applications. A funnel-shaped mold 43 is located above the wound winding receiver 10.
The surface contour of mold 43 has ribs which, when the mold is lowered in the direction of the arrow, enter the slots 14 formed between the segments 12. Depending on the process, ~w the mold can be lowered into the winding receiver 10 during the heating of the winding pass, or after the winding pass has been heated. This mold 43 has the function of pressing the wires in the slots 14 against the contour of cutout 13, after they have been heated and until the winding pass cools. This measure ensures that the wires receive a very uniform cross section after cooling. In the example shown in figure 9, the heating of the winding pass takes place by connecting the wire ends 45 to a suitable source of electric power (not illustrated), which heats the wrapping wire 32 covered with thermoplastic material, until the thermoplastic jacket softens. If the source of electric power is disconnected after the softening, and the winding pass has been cooled, preferably by blowing cold air, the wires forming the saddle coil are bonded to each other.
The removal of the saddle coil 46 from the winding receiver 10 is depicted in figure 10. First, the segments in groups 12.1, 12.2 are separated from the base 11, by moving them in the direction of the arrows. A device 47 is very advantageous for the removal, as well as for inserting the segments 12, because it grips all segments 12.1; 12.2 of a group of segments 12, at their upper edge. When the segments 12.1, 12.2 have been removed from the base 11, the baked saddle coil 46 can be pulled out of the cutout 13 in base 11 either upwards, or forwards with respect to the view of the figure.
The steps on the lower edge 15.u of base 11, also shown in this figure, are not limited to that side of the base 11. Rather, in another configuration example, these steps can also be formed on the upper edge 15.0 of base 11, as well as on both edges 15.0, 15.u of base 11. Furthermore, the steps on edges 15.0, 15.u can also be formed in the reverse order, so that the highest steps are not on the side of the coil edge, but rather in its center.

Claims (11)

1. Method for manufacturing a self-supporting saddle coil, characterised by the following steps given in the temporal sequence of their application:
(1) constructing a non-disposable winding receiver, in that a recess, which has the form of a trumpet halved along its center line and which is formed on one side of a base member, which forms one part of the winding receiver, is connected on its inner contour to segments, wherein the segments connected to the base member form slots and chambers for receiving wire strands and coil winding heads, (2) winding a coil shape predetermined by the slots and chambers by means of a wrapping wire covered with thermoplastic material, wherein a winding nozzle, from which the wrapping wire runs out, is located directly opposite regions of the slots and chambers in which the wrapping wire is inserted specifically into a slot or chamber, (3) heating the wrapping wire beyond the softening point of the thermoplastic material, (4) allowing the wrapping wire to cool, (5) removing the cooled and hence bonded wrapping wire from the winding receiver, to which end the shape possessed by the winding receiver during the winding is cancelled beforehand by removal of the segments from the base member.

2. A process according to claim 1, characterized in that a mold is placed over the winding receiver, either after step 2 or step 3 until the saddle coil has cooled and becomes bonded, where the surface structure of the mold squeezes the wire strands in the slots together.

3. A process according to claim 2, characterized in that wire ends are connected to a source of electric power, to heat the wrapping wire.

4. A device for producing a self-supporting saddle coil for, the apparatus comprising:
a winding receiver, on an outside and inside contour of which the saddle coil is formed, the winding receiver comprising:
a) a base whose side has a cutout in a form of half a trumpet cut through its centerline;
b) segments, which are connected to and are removable from the inside contour of the cutout, and which, when connected to the base, form slots and chambers for picking up wire strands and winding heads;
a winding device having a winding nozzle for forming the saddle coil by locating the winding nozzle, as well as a wrapping wire having a thermoplastic jacket emanating from the winding nozzle, directly opposite, an area of the winding receiver, on which the wrapping wire is laid in the slots to form the wire strands, and in the chambers to form the winding heads, and a device for heating the thermoplastic jacket of the wrapping wire.

5. A device according to claim 4, characterized in that the segments are divided into two groups of segments, and that one of the segment groups is connected and can be removed from the larger diameter cutout contour, and the other group of segments is connected and can be removed from the smaller diameter cutout contour.

6. A device according to claim 5, characterized in that a mold can be inserted in the cutout connected to the segments, the surface of which has ribs which, when inserted, press the wire strands between the segments against the contour of the cutout in the base.

7. A device according to claim 5, characterized in that an insertion and removal aid is available for the segments, which allows all segments to be simultaneously inserted into the cutout, and to be removed from the cutout.

8. A device according to claim 4, characterized in that the upper, the lower or also both edges of the base have steps in the area of the cutout.

9. A process according to claim 1, characterized in that wire ends are connected to a source of electric power, to heat the wrapping wire.

10. A device according to claim 4, characterized in that a mold can be inserted in the cutout connected to the segments, the surface of which has ribs which, when inserted, press the wire strands between the segments against the contour of the cutout in the base.

11. A device according to claim 4, characterized in that an insertion and removal aid is available for the segments, which allows all segments to be simultaneously inserted into the cutout, and to be removed from the cutout.