EP0676778B1 - High-voltage transformer - Google Patents

Abstract

The high voltage transformer has insulating housing parts (12, 13) which have at least one shaped tube (14). A connector region is formed inside the formed tube spout (14). The transformer also has at least one insulated high voltage cable (16) with bare ends (17). The end (17) is contacted inside the connector region as soon as the cable (16) has reached its end position in the tube (14). Each tube (14) has at least one shaped tongue (26) which extends into the free cross-section of the tube channel (15). The tongue (26) is sprung and its free end (28) is curved in the direction of the foot (19) of the tube channel (15). The outer cladding of the insulation (23) of the respective cable (16) has an optical marking (31). This, together with the upper end of the tube (14) displays whether the bare end (17) is securely contacted in the connector region. <IMAGE>

Description

Technical field

The invention relates to the design of high-voltage transformers for television sets, in particular to the strain relief of high-voltage cables which are conductively connected to the high-voltage transformers.

State of the art

Such an arrangement is known from FR-A-2 591 794 and relates to the strain relief of high-voltage cables which are connected to the high-voltage transformer of a television set. Another arrangement is described in DE-A-3 800 477. Both arrangements have in common that they have grommets on the insulating housing in which the windings of the coil arrangement are arranged. These grommets and the insulating material housing are usually made in one piece. In addition, arrangements are known in which the insulating material housing is connected to a further housing which contains the so-called adjuster arrangement for the focus voltage and the grid 2 voltage. With the arrangement in the latter sense, the grommets can also be partially molded onto the adjuster housing. Insulated cables are used to supply the high voltages generated in the coils of the high-voltage transformer to the corresponding assemblies of the television set. In general, this is solved in such a way that conductive rubbers are used in the base area of the grommets, which are conductively connected within the insulating material housing and / or the adjuster housing to the respective high-voltage branch of the coils.

The external connection of the high-voltage cable takes place in the form that the above-mentioned insulated cable at the end, which is connected to the high-voltage transformer should be connected, stripped and inserted with this end into the free opening of the spout and pushed forward until this end punctures in the base of the spout in the conductive rubber. In order to secure the high-voltage cable inserted into the conductive rubber against being pulled out of the grommet, a locking means is then pushed onto or into the grommet, which fixes the cable in the grommet channel.

In DE-A-3 800 477 this is solved in such a way that by pushing a sleeve onto the outer jacket of the grommet, the cable is pressed against a clamping nose arranged in the grommet channel by a tab connected to the sleeve and running in the grommet channel cuts the insulation of the cable and prevents the cable from being pulled out when the sleeve has found its end position on the grommet.

In FR-A-2 591 794 the pull-out safety or strain relief is achieved in that the end of the cable which is inserted into the grommet is provided with a sleeve whose outer surface has one or two longitudinal slots. If the cable provided with this sleeve is inserted into the sleeve channel, the outer surface of the sleeve is pressed from the wall of the sleeve channel into the insulation of the cable, so that the cable, when it has reached its end position in the sleeve channel, on the one hand with the stripped end in the conductive rubber punctures and is further secured against pulling out by the press connection between the sleeve wall, sleeve jacket and cable insulation. Depending on the design, the sleeve can be locked on the outside or inside with the spout.

Embodiments are also known in which the cable is first completely inserted into the grommet before a sleeve known from FR-A-2 591 794 is inserted between the inserted cable and the wall of the grommet channel.

However, these two-part locking arrangements - formed from the spout and sleeve - are disadvantageous when it is a matter of automating the process sequences described above. This is based on the fact that in each case a sleeve must be pushed onto the more or less flexible high-voltage cable before the actual connection process between the cable and the high-voltage transformer can take place. As experiments carried out by the applicant have shown in this connection, the embodiment shown in FR-A-2 591 794 in particular can only be satisfactorily automated if the sleeve diameter and the sleeves are of high manufacturing precision.

The invention is therefore based on the object of specifying an arrangement which avoids the disadvantages existing according to the prior art.

Presentation of the invention

This object is achieved according to claim 1 in that each grommet is formed with at least one integrally formed tongue which projects into the free cross section of the grommet channel, is designed to be resilient and projects with its free edge in the direction of the foot region of the grommet channel. If a cable is inserted into a grommet channel designed in this way, the resiliently arranged tongues which narrow the grommet channel are bent radially away. As soon as the cable has reached its end position in the grommet channel, the tongues claw with their edges into the insulation of the cable and thus prevent it from being pulled out when a tensile force is exerted on the cable. If the cable is provided with an optical marking on its outer jacket, it can easily be checked from the position of the marking to the upper end of the grommet whether the stripped end of the high-voltage cable securely contacts the conductive rubber arranged in the foot area of the grommet channel.

It is particularly advantageous if the respective free edge of each tongue is curved in accordance with claim 2. This ensures easy insertion of the cable or high-voltage cable.

Special guide elements in the spout channel can be dispensed with if, according to claim 3, the zenith of the arch of the edge faces away from the foot region of the spout channel.

If the width of the tongue is smaller than the diameter of the cable or high-voltage cable and the radius of the arc of the edge is smaller than the radius of the cable, the insertion of the cable into the grommet channel is further facilitated. This is because during the insertion process, only the edge areas of the edge pierce the insulation and the middle area of the edge rests on the insulation of the cable. If - after the cable or high-voltage cable has reached its end position in the middle channel - a force dissolving the connection is exerted on the cable, the edge areas of the edge penetrate deep into the insulation and pull the middle areas into the insulation during this movement, so that a very high stability against pull-out movements of the cable is achieved.

A high spring force of the tongues on the respective cable is given if the tongues are designed according to claim 5. The design of the tongues according to claim 5 allows the respective grommet to be provided with only one tongue for strain relief.

The latter is set out in more detail in claim 6 and has the advantage that the respective grommet only has to be accessible from one side to form the tongue narrowing the cross section of the grommet channel. This makes it possible to adjust the overall length of the grommet for the insulation of the connection area and the construction height for the Tongue training to limit necessary measure. In particular, it is not necessary, even with restricted accessibility of the spout, to design the spout so long, ie beyond the necessary dimension just mentioned, that the spout is freely accessible, for example, from opposite sides.

Brief description of the figures

Figur 1

eine Seitenansicht einer Tülle gemäß der Erfindung;

Figur 2

eine Schnittdarstellung durch eine Tülle gemäß der Erfindung;

Figur 3

einen Schnitt A - A durch eine Tülle gemäß Figur 2;

Figur 4

eine weitere Darstellung gemäß Figur 1;

Figur 5

eine weitere Darstellung gemäß Figur 2; und

Figur 6

eine Darstellung eines Hochspannungstransformators gemäß dem Stand der Technik.

Show it:

Figure 1

a side view of a spout according to the invention;

Figure 2

a sectional view through a spout according to the invention;

Figure 3

a section A - A through a spout according to Figure 2;

Figure 4

a further representation according to Figure 1;

Figure 5

a further representation according to Figure 2; and

Figure 6

a representation of a high voltage transformer according to the prior art.

Ways of Carrying Out the Invention

FIG. 6 shows a high-voltage transformer 10 with strain relief in accordance with the prior art, the coil arrangement 11 of which is arranged within the insulating material housing 12. The right side of this housing 12 is connected to the so-called adjuster housing 13, which is also made of insulating material and accommodates the adjustment resistor arrangement (not shown) for the focus and grating 2 voltage. The illustration clearly shows that both the insulating material housing 12 and the adjuster housing 13 have molded grommets 14.1 to 14.3. The grommet 14.1, which is connected to the insulating material housing 12, is shown in section, while the grommets 14.2 and 14.3 are only shown in a side view, the upper part of the grommet 14.3 being covered by the grommet 14.2.

In the spout 15 of the spout 14.1 is an isolated High-voltage cable 16.1 inserted. The end position of the cable 16.1 shown in FIG. 6 in the grommet duct 15 makes it clear that the stripped end 17 of the cable 16.1 is inserted into a conductive rubber 18 which is placed in the foot region 19 of the grommet duct 15.

This conductive rubber 18 is connected to the high-voltage source (not shown further) via a pin 20. The respective high-voltage cable 16 is locked at the upper end of the respective grommet duct 15. These areas are identified for the grommets 14.1 and 14.2 by dash-dotted circles. The sectional view of the grommet 14.1 can be seen that in the upper end of the grommet channel 14.1, a sleeve 21 is inserted between the inner wall 22 of the grommet channel 15 and the outer jacket of the insulation 23 of the high-voltage cable 16.1 and via lugs 24 formed on the outer jacket of the sleeve 21, which in recesses 25 engage the wall of the grommet channel 15, with the grommet 14.1 is locked. This sleeve 21 is provided with slots (not shown) in the longitudinal direction and has a slightly enlarged outer diameter compared to the inner diameter of the spout channel 15. This causes that in the locked state of the respective high-voltage cable 16 in the grommet 14, the inner jacket of the sleeve 21 is pressed into the insulation 23 of the high-voltage cable 16 and thus effectively prevents the high-voltage cable 16 from being pulled out of the grommet 14.

1 shows a spout 14 according to the invention in side view, in which an insulated high-voltage cable 16 is inserted. The upper end of this grommet 14 has a tongue 26 which is formed by an essentially U-shaped recess 27 in the grommet wall. The free edge 28 of this tongue 26 points in the direction of the foot region 19 of the spout 14. In addition, the free edge 28 of the tongue 26 is designed in the shape of an arc, the zenith of the arch corresponding to the foot region 19 of the spout 14 is turned away. 1 that the free edge 28 is provided with a chamfer 29. In the exemplary embodiment shown in FIG. 1, the width of the free edge 28 corresponds to the outer diameter of the high-voltage cable 16, as the clear view through the recess 27 shows the high-voltage cable 16.

The sectional view according to FIG. 2 shows how the locking and contacting of the high-voltage cable 16 is carried out in the grommet. The spout channel 15, which runs through the spout 14 from its upper end to its base region 19, has a circular cross section in its upper region, while the base region 19 is slightly conical. At the end of the foot region 19, a conductive rubber 18 is inserted, which is conductively connected to the high-voltage source (not shown). Two tongues 26, which have already been explained in connection with FIG. 1, are formed near the upper end of the spout 14. Both tongues 26 face each other. The free ends 28 of the tongues 26 are directed into the interior of the spout duct 15, narrowing the inner cross section of the spout duct 15.

This design, the tongues 26 narrowing the cross section of the spout channel 15, can be formed very simply in that the tongues correspond to the wall profile of the spouts during the spraying of the insulating material parts 12, 13 provided with the spouts 14 and only then by means of a hot stamping tool into the spout channel 15 narrowing position shown in Figure 2 are bent.

If a high-voltage cable 16 provided with a stripped end 17 is inserted into the upper end of the grommet duct 15, the tongues 26 narrowing the cross section of the duct 15 are bent away in the direction of arrow P as soon as the insulation 23 of the high-voltage cable 16 is on the Flanks 30 of the tongues 26 touches. As the insertion movement of the cable 16 into the channel 15 continues, the outer jacket of the insulation 23 slides past the arcuate edges 28 of the tongues 26 until the high-voltage cable 16 reaches the foot region 19 and the stripped end 17 penetrates the conductive rubber 18. This final state is shown in Figure 2.

Already during the insertion movement of the high-voltage cable 16 into the grommet duct 15, but at the latest when the high-voltage cable has reached its end position in the grommet duct 15, the tongues 26 are reset in the opposite direction of the arrow P, whereby the chamfers 29 (FIG. 1) into the insulation 23 cut the high-voltage cable 16. This incision is shown schematically in FIG. 2.

It can easily be seen from FIG. 2 that when a tensile force acts in the direction Z on the high-voltage cable 16, the edges 28 of the tongues push deeper into the insulation 23 of the high-voltage cable 16.

However, the latter does not mean that the connection shown in connection with FIG. 2 can only be released by destroying the spout 14 or the tongues 26. Rather, to detach the high-voltage cable 16, its tongues 26 can only be moved in the direction of arrow P. The latter can be done, for example, by moving the tongues 26 in the arrow direction P through the incisions 27 (FIG. 1) using a suitable tool. A further possibility of solving the high-voltage cable 16 is provided if the flanks 30 of the tongues 26 are pressed out of the insulation 23 of the high-voltage cable 16 by a tool inserted through the upper opening of the grommet channel 15.

To make it clear that the stripped end 17 of the High-voltage cable 16 in any case contacted the conductive rubber 18, has proven to be useful to provide the high-voltage cable 16 on its outer jacket with a mark that indicates whether the stripped end 17 is securely inserted into the conductive rubber, taking into account all tolerances. In the present case, this marking 31 is designed as a color ring. Once the high-voltage cable 16 has reached its end position in the grommet channel 15, the guiding rubber 18 is securely contacted when the lower edge 32 of the color marking is no longer visible at the upper end of the grommet 14. Since the stripped end 17 of the high-voltage cable 16 is pierced deep into the conductive rubber 18 in the exemplary embodiment shown in FIG. 2, the lower edge 32 of the marking 31 lies below the upper end of the grommet 14.

FIG. 3 shows a section AA according to FIG. 2. This illustration shows that the width of the edge 28 is smaller than the outside diameter of the high-voltage cable 16. The radius of the edge 28 also has a smaller radius than the high-voltage cable 16. This ensures that only the edge regions 33 of the edge 28 cut into the insulation 23 of the high-voltage cable 16 during insertion of the high-voltage cable 16 into the grommet duct 15. The middle region of the edges 28 is only in contact with the outer jacket of the insulation 23 when the high-voltage cable 16 is inserted. This design has the advantage that the insertion process can be carried out with a significantly lower insertion force. However, this design does not impair the security against pulling out the high-voltage cable 16. If a tensile force Z shown in FIG. 2 acts on the high-voltage cable 16, the edge regions 33 of the edges 28 penetrate deeply into the insulation 23 of the high-voltage cable and thereby cause the central regions of the edges 28 to also penetrate into the insulation 23 of the high-voltage cable 16 incise.

FIG. 4 shows a further side view of a spout 14. In contrast to the representation according to FIG. 1, the tongue 26 is trapezoidal in FIG. 4, the width of the transition region 34 between the tongue 26 and the spout 14 being greater than the width of the free edge 28 of the tongue 26. In the exemplary embodiment according to FIG Free edge 28 of the tongue 26 is arcuate and has a width corresponding to the high-voltage cable, as the view through the cutout 27 in the wall of the spout 14 shows. Matching the width of high-voltage cable 16 and free edge 28 is also not necessary in the exemplary embodiment according to FIG. 4. Rather, if the advantages which are explained together with FIG. 3 are to be achieved, the width of the free edge 28 can also be made narrower than the diameter of the cable 16.

If the tongues 26 are trapezoidal, the strain relief per grommet 14 can be realized with one tongue 26 - as shown in FIG. 5 - because the one trapezoidal tongue 26 exerts a sufficiently great spring force on the high-voltage cable 16. This means that in the case of an adjuster arrangement 13 according to FIG. 6, the grommets 14.2, 14.3 formed there do not necessarily have to protrude above the upper edge 35 of the adjuster arrangement 13, but when only one trapezoidal tongue 26 (FIG. 4) is formed on the side facing away from the insulating material housing 12 each spout 14.2; 14.3 can be limited to a length dimension which is just necessary for isolating the connection in the foot region 19 and for forming a tongue 26 in the upper region of the spout.

In addition, it should be noted that the formation of the tongues 28 is not necessarily limited to the number 1 or 2.

Rather, in another embodiment (not shown), 3 or 4 tongues 28 can also be formed in the spout channel 15 as well. Furthermore, the shape of the edge 28 is not limited to the circular arc shape explained in connection with FIGS. 1-3. In this context, it is pointed out that the zenith of the arc of the edge can also be directed in the direction of the foot region 19 of the spout. In this case, however, it is necessary to additionally form guide elements on the inside of the grommet duct 15 in order to prevent the high-tension cable 16 from slipping in the grommet duct 15. The application of the invention is not limited to the connection of high-voltage cable and high-voltage transformer in television sets. For example, the connection between the high-voltage cable and the anode cap of the television set can also be designed according to the invention. Low-voltage connections can also be equipped with the strain relief according to the invention.

Claims (6)

1. High-voltage transformer for television sets,

   - having housing parts (12, 13) made of insulating material, which have at least one integrally-moulded sleeve (14),

   - having a connection region formed inside the integrally-moulded sleeves (14), and

   - having at least one insulated high-voltage cable (16) whose stripped end (17) makes contact in the connection region as soon as the cable (16) has reached its end position in the sleeve (14), and which, in this end position, is secured in the sleeve channel (15) by at least one tab (26) integrally-moulded to the sleeve (14) and projecting into the free cross-section of the sleeve channel (15),

      characterised in that
   each tab (26) is of spring construction and has an edge (28) pointing towards the base region (19) of the sleeve channel (15), that the high-voltage cable pushed into the sleeve channel is secured solely by the action of all the tabs provided in the sleeve channel, and that a visual mark (31) is provided on the external sleeve of the insulation (23) which, together with the upper end of the sleeve (14), indicates whether the stripped end (17) is making reliable contact in the contact region.
2. High-voltage transformer according to Claim 1,
   characterised in that
   the free edge (28) of the tab (26) is arc-shaped.
3. High-voltage transformer according to Claim 2,
   characterised in that
   the vertex of the arc of the free edge (28) of the tab (26) faces away from the base region (19) of the sleeve channel (15).
4. High-voltage transformer according to Claim 3,
   characterised in that

   - the width of the tab (26) is less than the diameter of the high-voltage cable (16) and

   - the radius of the arc of the edge (28) is less than the radius of the high-voltage cable (16).
5. High-voltage transformer according to Claim 1,
   characterised in that
   the respective tab (26) is of trapezoidal shape, the transition region (34) between the tab (26) and the sleeve wall being wider than the free edge (28) of the tab (26).
6. High-voltage transformer according to Claim 5,
   characterised in that
   each sleeve (14) has only one tab (26).

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