EP0236642B2 - High-voltage transformer - Google Patents

Description

The present invention relates to a high voltage television transformer without cables high voltage and potentiometric block output removable. It relates in particular to the internal and external connections of the transformer.

A high voltage (HV) connection, such as a car spark plug connection, is usually made using at least one terminal crimped on the connecting wire, this terminal can be a terminal female coming to cap a terminal or a terminal male, or possibly a male terminal inserting in a bowl or in a female pod. Such a connection therefore requires crimping on the connecting wire a lug, which requires an apparatus special.

Typically a high voltage transformer intended for the supply of color cathode ray tubes has an integrated potentiometer block which delivers the tensions of the prefocusing grids G3 and screen G2 of these tubes. However, the cable high voltage and G2 grid output cables and G3 are fixed and integral with the transformer. These cables, varying in length depending on the user, interfere with manufacturing, handling, and mounting of transformers. In addition, the potentiometric block, integrated into the transformer, requires wiring operations which can affect the reliability of the product.

We know from document FR-E-71570 a beam oscillation blocking element automotive ignition. This blocking element has a sleeve of insulating material in which is arranged a pellet of elastic material conductive. According to a first embodiment, the patch includes, before mounting in the sleeve, its own output connectors. We cannot therefore use this device to ensure the connection between removable conductors. According to the second embodiment described in this document, we have in an insulating sleeve a pad of elastic conductive material in each end of which a cavity is formed intended to receive a component such as a head candle. This second embodiment does not also does not ensure the connection between removable conductors with rigid core.

It should be noted that the use of conductive silicone contacts is already known.

The document "Philips Plastics and Metalware Factories Bulletin, January 1984 n ° 75" describes in particular a new use of such silicones for a "potentiometer designed by Elcoma Roeselare for the adjustment of the focusing voltage in television sets .... conductive silicone contacts are used to make a reliable electrical connection between the wiring and the underlying layer .... The conductive silicone pellets are stretched between the contact surfaces of the underlying layer and the cavity of the housing in synthetic material .

The document "Neues aus der Technik 1985 n ° 2, page 2, article 29" describes a part of a transformer used in a television set to generate the high line deflection voltage. This document includes a figure with reference numbers. The numbers refer to this figure when talking about this document. The assembly described in this document aims at a special configuration of the focus voltage output chimney (3) so that the potentiometric block (19) can be plugged in if necessary, directly in chimneys forming part of the protective envelope through the openings (7, 9), without causing complex modifications to the transformer. The contacts (23, 24) of the potentiometer (19) are pressed into conductive rubber plugs (13, 17) located at the bottom of these chimneys.

The description of an exemplary embodiment of a removable potentiometer mountable on a high voltage transformer is described moreover in patent application EP 0 068 494 (SANYO).

The subject of the present invention is a transformer as described in claim 1.

The high voltage transformer conforms to the invention comprises connection means removable to connect output cables high tension. These means preferably include, for each transformer output a hanging device quick cable and device contact with the conductor or the cable core. According to a preferred embodiment of the invention, the quick coupling device is a device of clipping comprising a first integral part a fully molded chimney with the envelope covering the winding coating insulation of the transformer, the inside diameter of this chimney being substantially equal to the diameter outside of the cable, the base of this chimney being located above or near the terminal or corresponding output socket, this terminal or socket being connected to a conductive pad, of preferably silicone loaded with conductive material, this pellet sealingly closing the base from the chimney, the second part of the device clip being attached to the cable near its end and positioned so that the end conductor or cable core either good contact with said patch when the end cable is pushed into the chimney and that the two parts of the quick coupler are in mutual engagement.

• la figure 1 est une vue en coupe partielle d'un transformateur haute tension conforme à l'invention, avec deux câbles de sortie ;
• la figure 2 est un vue de dessus très simplifiée d'un bloc potentiométrique disposé sur un circuit imprimé distinct du transformateur, ce bloc étant relié à un transformateur tel que celui de la figure 1 ;
• la figure 3 est une vue de face très simplifiée d'un transformateur haute tension conforme à l'invention, montrant plusieurs possibilités de fixation du bloc potentiométrique, et
• la figure 4 est une vue en coupe d'un dispositif de connexion HT exposant pour une meilleure compréhension un exemple de connexion comportant une pastille conductrice. L'exemple représenté figure 4 se rapporte à la liaison entre une bougie d'automobile et un fil d'alimentation en THT de cette bougie.

The present invention will be better understood on reading the detailed description of several embodiments, taken as nonlimiting examples, and illustrated by the appended drawing, in which:

• Figure 1 is a partial sectional view of a high voltage transformer according to the invention, with two output cables;
• FIG. 2 is a very simplified top view of a potentiometric block arranged on a printed circuit separate from the transformer, this block being connected to a transformer such as that of FIG. 1;
• FIG. 3 is a very simplified front view of a high voltage transformer according to the invention, showing several possibilities of fixing the potentiometric block, and
• Figure 4 is a sectional view of a HT connection device exposing for a better understanding an example of connection comprising a conductive pad. The example shown in FIG. 4 relates to the connection between an automobile spark plug and a THT supply wire for this spark plug.

In the example of Figure 4, shown when the connection is established, it is a question of realizing a connection between a spark plug 30 and a HT 31 supply wire. For this purpose, produces a sleeve 32 of rigid insulating material having approximately in its middle a constriction 33. One end of the sleeve 32 comes to cap the candle 30, the constriction 33 forming stop for the upper part of the candle. For seal the spark plug side, you can practice near the edge of this end of the sleeve an inner groove in which has an appropriate seal 34. The electrode candle ends with a point metallic axial 35.

In the other end of the sleeve 32, the inner profile is cylindrical, insert by forcing slightly a conductive pad 36, arriving in stop on the throttle 33. The length of said other end of the sleeve 32 is greater than the length of the patch 36, which is fixed to it by a ring 37 which can either be screwed or glued to it, be force-fitted. The hole of the ring 37 is cylindrical towards the outside of the sleeve and conical towards the pad 36. The cylindrical part of this hole has a diameter slightly smaller than the diameter outside of the wire insulation 31, while its conical part is used to guide, if necessary, the end stripped (end of the core) 38 of the wire 31, which sinks into the pad 36. Thus, the ring 37 advantageously acts as a means sealing of the connection on the wire side 31. The tip 35 is inserted into the pad 36 opposite of the core 38. The patch 36 is advantageously in silicone charged with electrically conductive powder. The tip 35 as well as the core 38 can be there push in easily, without necessarily being pointed and without the risk of twisting, the soul 38 still have to be relatively rigid.

Of course, such a connection does not allow not to pass very high currents, but is very well suited for low currents such as than candles from cars or transformers high voltage television.

The use of a device such as shown in figure 4 is described with reference to a high voltage transformer for TV, with focus voltage output and a high voltage output for the anode of cathode ray tube, but it is understood that the invention applies to high transformers voltage for televisions may have additional outputs.

The high voltage transformer 1 shown in FIG. 1 essentially comprises a circuit magnetic 2 and a coil 3 (not shown in detail) with several windings. This transformer may for example be of the "split diode" type, that is to say of the split secondary winding type, with diode separation. Winding 3 is sealed with a molding resin, this coating being coated with an envelope protective not shown.

The transformer 1 has on one of its faces, for example the underside, several pins 4 connected to primary windings, and possibly low secondary windings winding voltage 3, these pins 4 being intended to fix transformer 1 on a circuit appropriate printed and making connections electric with the conductors of this printed circuit.

The transformer 1 comprises, in the case present, two high voltage outputs: one output focusing voltage, to supply, via a cable and a potentiometric block, the G2 grids and G3 of a cathode ray tube (not shown) and another very high voltage output for power supply via a removable cable 6 of the anode of said cathode ray tube.

In Figure 1, there is shown on exploded in cuts the construction details allowing the focusing voltage output connection it being understood that the connection of the other high voltage output is performed in a similar fashion.

At the time of molding the envelope of protection of the coating resin of the winding 3, it is planned to form projecting on the envelope of protection, preferably opposite the pins 4, two chimneys 7, 8 intended to receive the ends of cables 5, 6 respectively. These chimneys are short enough not to interfere with use and handling of the transformer, and not to make them fragile, while being long enough to avoid electrical bypass with any part connected to the mass. Their outer length can advantageously be about 2 to 4 cm. Their thickness walls, in particular at their base, must be sufficient not to make them fragile, this thickness being advantageously from 2 to 5 mm approx.

Chimneys 7 and 8 communicate with the interior space of said envelope, and in particular with the connection terminals of the sockets or corresponding high-voltage winding ends. These chimneys can either stop at their base or junction with the envelope, either, as shown in the drawing, extend inside the envelope to reach the connection terminals, the conduit 9 thus formed at the inside of the envelope can be used to accommodate elements such as resistors, capacitors, elements protection, etc.

The chimney 7 comprises, substantially at the level from its base, a slight conical constriction 10, flaring outwards, allowing properly center the end of the cable in the chimney. Right after this constriction, inward, we has in the chimney 7, and in this case more precisely in the duct 9, a patch 11 of conductive material, sealingly sealing the fireplace. According to a preferred embodiment of the invention, this tablet is made of charged silicone powder with good electrical conduction.

We push into the inside of the patch 11 a conductor 12 connected in a manner not shown, to the high voltage winding providing the focusing voltage required for gates G2 and G3.

An advantage of the invention consists in driving into the face inside of the pad 11 the conductor 13 of a discharge resistor 14 called "bleeder", the other conductor of this resistor being pressed, of not shown, in the inside of the chimney disc 8.

A device is put on the end of the cable 5 hook 15, appearing for example, as shown in the drawing, as a socket with one end flared as a collar taper 16 and the other end of which is split according to one or two generators. The inner diameter of this socket is substantially equal to the cable outer diameter 5.

Furthermore, the chimney 7 has at its free end an engaging device 17 cooperating with the hook device 15. Depending on the mode preferred embodiment shown in the drawing, the device 17 is a lug or a protuberance formed on the inner wall of the chimney 7. According to another embodiment (not shown), the clipping device is a cylindrical socket strung on the chimney and having such lug. The dimensions of the collar 16 of the lug 17 are such that they can snap in while holding firmly the cable 5 in the chimney 7, and that the cable 5 can be removed if necessary by exerting a strong traction on this cable, without damage them. Lug 17 can be made with the same material as that of the chimney 7, or may be metallic and attached to the chimney. The aforementioned sockets are made of plastic appropriate.

The socket forming the hook 15 is positioned on cable 5 so that the stripped end 18 of this cable is inserted at least 3 mm into the pad 11 when the hook and lug are clipped to ensure good electrical contact and avoid ozone formation.

We have represented in a simplified manner on the FIG. 2 a potentiometric block 19, comprising potentiometers 20 and 21. The cursors of potentiometers 20 and 21 are connected, so represented, by cables 22 and 23 to grids G2 and G3 respectively, from the cathode ray tube supplied by transformer 1. This potentiometric block 19 is part of one of the printed circuits of television, or is fixed on one of these circuits. Moon of the ends of the cable 5 is connected to the transformer, the other end of cable 5 is connected to this block, advantageously by a device conductive pad connection similar to that equipping the chimney 7. The cables 22 and 23 can be permanently attached to block 19 or removable, and in the latter case, we can also use a quick hook and conductive pads.

We have represented, in a simplified manner, on the Figure 3, an embodiment for which the block potentiometer 24, with its potentiometers 25, 26 is fixed on one side of the transformer by clipping (block 24 shown in solid lines for a first solution, and in broken lines for two other possibilities). Connection cables 27 and 28 at grids G2 and G3 of the cathode ray tube can be fixed on block 24 so permanent or removable, in the latter case, also using conductive pads.

Removable attachment of very high voltage cable 6, with its suction cup 6A, in the chimney 8 is similar to that of cable 5 in the chimney 7, and will not be described in more detail.

Thanks to the invention, the transformer can be placed high voltage on its printed circuit in the position for which the influence of his radiation on its environment is the least, and we can position the potentiometric block where it’s easy to adjust your potentiometers.

Another advantage of the invention is to allow to dissociate the transformer from the potentiometric block and corresponding cables, which simplifies repairs in the event of a one of the elements.

Finally, the transformer manufacturer no longer has to deal with bulky cables, and the user can set up the elements of the high circuit tension at the end of manufacturing.

Claims (6)

1. High-voltage transformer with removable potentiometric unit, intended for supplying focusing and anode voltages of a television cathode-ray tube by means of rigid core removable conductors (5, 6), each having a stripped end, the transformer comprising:

   an insulating protective covering provided with two chimneys (7, 8), a first one and a second one, which are moulded integrally with the protective covering, the first (7) constituting the focusing high-voltage output and the second (8) constituting the high-voltage output of the anode of the cathode-ray tube, a block (11) of silicone loaded with a conducting powder being fixed in each chimney (7, 8), a first end of a so-called bleeder resistor (14) being pushed into the block of the first chimney (7), the second end of this resistor (14) being pushed in to the block (11) of the second chimney (8) inside the protective covering, these blocks (11) making a connection between conductors (12) which are connected to the high-voltage windings of the transformer and are pushed into the blocks inside the protective covering, and the removable cables (5, 6), the stripped end of the rigid core of each removable cable (5, 6) being readily able to be pushed into the outward face of the block (11) of their respective chimney.
2. Transformer according to Claim 1, characterised in that each output chimney (7, 8) comprises an uncouplable rapid fastening device (17) for a conductor cable (5, 6), this conductor cable being fitted with a hook device (15) interacting with the said fastening device.
3. Transformer according to Claim 1 or 2, characterised in that each output chimney (7, 8) comprises means for sealing the connection at its two ends (37, 34).
4. Transformer according to any one of the preceding claims, characterised in that each chimney (7, 8) comprises a slight conical constriction (10) for guiding the end (18) of the corresponding conductor cable (5, 6).
5. Transformer according to any one of the preceding claims, characterised in that the potentiometric unit (19) is fixed to or forms part of a printed circuit.
6. Transformer according to any one of Claims 1 to 4, characterised in that the potentiometric unit (24) is removably fixed to one of the faces of the transformer.

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