DE19620340C1 - Circuit board for precise placement and soldering of electronic components e.g. for fitting overvoltage protection modules - Google Patents

Abstract

The circuit board (1) is provided with a number of shallow recesses (e.g. 2) each matched to the external contour of the component to be placed in it. These ensure that the components are held in the desired positions after the solder paste has been applied and before the soldering operation is performed. The components may include an overvoltage diverter (4), two varistors (5), and two resistors (6) with positive temperature coefficients. Connection surfaces (7) are arranged at the edges of the recesses, whose inside faces (9) are at least partially metallised.

Description

The invention relates to surge protection connector according to the preamble of claim 1, the usually also referred to as fail-safe contact and especially in telecommunication systems can be used.

Such a surge protection plug is already in the DE 40 26 004 C2 described.

A stands there Sheet metal part in connection with the surge arrester and on the sheet metal part is a solder joint with a Connected slide against which a spring acts. He the surge arrester heats up in impermissible Way and thus also the sheet metal part, the solder melts  turn off and the slide is driven by the force of the The spring moves and the surge arrester becomes short closed. Such thermal protection is required Tends relatively many items that have a high Fer manufacturing and assembly costs. Besides, is the required space is relatively large. The use of springs in particular is related to be critical of automated assembly because there are special requirements for this.

In the solution described in DE 40 26 004 C2 are additional elements for making one Connection to earth potential required.

Furthermore, DE 33 23 687 C2 is an over span dungsabitermagazin for terminal strips of the telecommunications Detechnik known in which for the thermal Protection for every gas spark gap of a two-way cable An S-shaped bow spring can be inserted from above is who has a solder pill on one leg as well a switch contact and on her other leg has a locking device. This thermal too Protection is provided by using the additional iron which is complex to manufacture and prone to failure.

In DE G 90 12 951 U1 there is a protective plug for Lei in a distributor of a telecommunications plant, e.g. B. for telephone switching systems, be wrote that when heated as a result of a longer persistent surge can be grounded. Therefor are at least one on the surge arrester Melting piece, a contact part and a thermistor orderly and with appropriate heating of the Thermi stors the melting piece melted and with With the help of additional springs the or several con  clock parts are brought into earth contact. This one too Protective plug has several individual elements, which correspond to assembly. In addition, must sen the contact parts and the melting piece relatively be dimensioned exactly to each other.

The disadvantage also affects the protective plug described in DE 44 37 122 A1, the individual parts are very complicated and what is referred to as a so-called slide Element also a relative movement if necessary must exercise to provide reliable protection against over to ensure tension. Special requirements are related to various elements the geometry and spring forces.

DE 42 25 484 C1 describes a protective plug, in which a surge arrester with two electrodes to be used in one of the electrodes uses a melting element that when triggered a Can establish short circuit condition.

Furthermore, there is an air spark in DE 44 03 053 C1 stretch to set the maximum voltage on one aged surge arrester, which is an electric the arrangement in a capsule filled with noble gas has been described. By the appearance of a Overvoltage in a telecommunications system ignites the Surge arrester filled with noble gas ter, so that the overvoltage through the low impedance Connection via this surge arrester failed can be tet. In the event that due to the Zün of the surge conductor is heated accordingly a melting pill melts through the generated one Heat, so that biased tongues by spring  come into contact with a lid and the Surge arrester can be closed briefly.

It is therefore an object of the invention to provide a surge protection plug for terminal strips of the telecommunications technology from a pluggable insulating material housing with a surge arrester with two each an external electrode connected to a telecommunication wire and a central electrode connected to the earth rail, and with thermal overload protection, through which in the event of excessive heating of the overvoltage conductor connected the telecommunication wires to the earth rail to be the easier to propose and therefore  Assembled safer and assembly and manufacturing is more friendly.

According to the invention, this task is performed with the in claim 1 resolved characteristics. Beneficial Design forms and further training of the Erfin result when using the in the below ordered claims features.

The surge protective plug designed according to the invention combines the two functions "Earth contact "and" fail-safe contact "in one part, the by punching and then by bending can be trained speaking. This execution has the advantage that the assembly effort is essential is reduced and for insertion into the housing only linear joining movements for use of assembly machines are particularly cheap, by must be performed.

Another advantage is that the number the transition points that are charged with surge current that can be reduced.

The second contact bracket is in the assembled state a constant pretension against the over voltage arrester existing external electrodes. Wuh The thermo acts in the normal operating state element against the preload of the second contact bracket or isolates the second contact bracket from over the outer electrodes and thus prevents an electrically conductive connection between the con clock element and the outer electrodes of the span voltage arrester is present. The thermocouple can as a solder pill attached to the second contact bracket  be formed or in a corresponding in the con Engage the recess in the clock bar. At this latter solution becomes the contact element initially without the thermocouple in the housing of the Protective plug fixed. After the connection of the Ge housing with the circuit board of the protective plug the thermocouple subsequently in the second contact block clicks into place and the fail-safe contact is complete preloaded and made functional.

The thermocouple can be a molded part made of a material al consist, for example, of a metal that Er heating melts and so the movement of the second con clock bar towards the outer electrodes of the Overvoltage conductor releases, so that a conductive Connection between the telecommunication wires and the earth rail is manufactured. The material will be with ner melting temperature selected so that damage against the system or even a fire hazard can be sen.

The thermocouple can also be made of one material exist that with a corresponding heating of the Surge arrester only softens and so un ter the biasing force of the second contact bracket yields that this with the outer electrodes in Kon tact and connect to them can manufacture.

You can also use Bimetallic or well-known memory alloys, which in are able to heat the second contact bracket the contact element for connection to the Au release the outer electrodes of the surge arrester.  

The thermocouple can also consist of an insulating Lacquer or an insulating film exist between outer electrodes of the surge arrester and the resiliently attached to this second con Clock bar is arranged and this electrically against isolated from each other. The paint or film melts when heated, which creates the conductive connection is posed.

At least one as is preferably on the contact element Retaining leg on the first Retainer opposite side of the span on the insulating surface fe dernd fittingly trained. This will make one side loading of the solder joint between the Surge arrester and the Lei carrying it avoided.

In the following, the invention is to be explained with reference to tion examples are described in more detail. Here demonstrate:

Fig. 1 shows a contact element according to a first embodiment of the invention,

Fig. 2, the patch on a surge arrester contact element according to Fig. 1,

Fig. 3 shows a protective plug for use in telecommunications systems using the contact element according to Fig. 1, and

Fig. 4 shows a contact element according to a second embodiment of the invention.

The contact element 1 shown in Fig. 1 comprises a first resilient contact bracket 2, the processing in Rich on a not visible in this illustration, the center electrode 3 of a surge arrester 4 is angled from. The contact bracket 2 touches the center electrode 3 , which is connected in the event of an overvoltage within the surge arrester 4 with its outer electrode 5 and 6 . The outer electrodes 5 and 6, for their part, are in the inserted state of the protective plug, each with a telecommunication wire connected. The contact element 1 has a plug-in receptacle in the form of two bent resilient tabs 7 , into which a contact flag 8 connected to an earth rail is inserted. Thus, in the event of an overvoltage, an earth connection from the Fernmeldea countries a and b via the outer electrodes 5 and 6 , the surge arrester 4 , the central electrode 3 , the contact bracket 2 and the tabs 7 of the contact element 1 and the contact flag 8 to the earth rail Herge provides .

The one-piece contact element 1 has a second resilient contact bracket 9 , which merges into a transverse web 10 at its free end. The two ends of the crossbar 10 lie opposite the outer electrodes 5 and 6 of the surge arrester 4 . Between the ends of the crossbar 10 on the surge arrester 4 facing side of the contact bracket 9, a solder pill 11 is attached, which rests under the spring force of the contact bracket 9 on the insulating outer surface or the central electrode 3 of the surge arrester 4 and thereby the ends of the crossbar 10 Contact bracket 9 at a distance from the outer electrical 5 and 6 holds. With excessive heating of the surge arrester 4, for example, can occur when a he creased tension between the two telecommunications cores is over a longer period, but does not lead to trigger of the arrester 4, melts the solder bead. 11 This can therefore no longer prevent the crossbar 10 from applying the spring force of the contact bracket 9 to the outer electrodes 5 and 6 of the surge arrester 4 , so that now an earth connection between them and the earth rail via the contact element 1 with the crossbar 10 , the contact bracket 9 and the tabs 7 and the contact tab 8 .

In Fig. 1, two support legs 12 of the contact element 1 Kon with respect to the contact bracket 2 on the other side of the surge arrester 4 are arranged so that they serve as an abutment and a one-sided load of the soldered connection between the surge arrester 4 and the Lei carrying this prevent terplatte.

In Fig. 2, the contact element of FIG. 1 is shown placed on the surge arrester 4 and it can also be seen that the holding legs 12 rest on the insulated outer surface of the surge arrester 4 on both sides of the center electrode 4 .

In Fig. 3, the protective plug is shown in the inserted state, wherein several electronic components, such as PTCs 15 , and the surge arrester 4 are placed on a circuit board 13 within a housing 14 . The contact element 4 is placed on the surge arrester 4, as already shown in FIG. 2. At the same time, it is also held by the housing 14 .

In Fig. 4 another embodiment of a con tact element 1 is shown. The second contact bracket 9 is opposite the first contact bracket 2 and the thermocouple 1 is the outer circumference of the surge arrester 4 adapted so that it forms the abutment to the contact bracket 2 and therefore the support legs 12 are not required. The thermocouple element 11 has an inner contact surface 16 in the form of a circular arc section, the radius of which is equal to the radius of the cylindrical surge arrester 4 . In the central section of the crosspiece 10 , a recess is incorporated, into which the thermocouple 11 can be inserted and can be snapped into it.

Claims (9)

1. Overvoltage protection plug for terminal strips of telecommunications technology from a pluggable insulating material housing with a surge arrester ( 4 ) with two external electrodes ( 5 , 6 ) each connected to a telecommunication wire and a central electrode ( 3 ) connected to the earth rail, in the event of excessive heating of the surge arrester ( 4 ), the telecommunication wires are connected to the earth rail, characterized in that a one-piece contact element ( 1 ) is provided which is plugged into the housing and which is in contact with the central electrode ( 3 ) of the assembled surge arrester ( 4 ) when plugged in first contact bracket ( 2 ), a plug-in receptacle ( 7 ) for a fixedly connected to the earth rail contact lug ( 8 ) and a resilient second contact bracket ( 9 ) with a cross web formed at its free end ( 10 ) by a thermocouple ( 11 ) held at a distance from the outer electrodes ( 5 , 6 ) and in the event of excessive heating due to a change in shape of the thermocouple ( 11 ), due to its resilient property, it can be brought into contact with both outer electrodes ( 5 , 6 ). 2. Protective plug according to claim 1, characterized in that the second contact bracket ( 9 ) with the ends of the cross piece ( 10 ) each Weil with one of the outer electrodes ( 5,6 ) can be brought into contact and between the ends of which the thermocouple ( 11 ) is located. 3. Protective plug according to claim 1 or 2, characterized in that the thermocouple ( 11 ) is a molded part which melts when heated. 4. Protective plug according to claim 1 or 2, characterized in that the thermocouple ( 11 ) is made of a softening material when heated. 5. Protective plug according to claim 1 or 2, characterized in that the thermocouple ( 11 ) is a bimetal. 6. Protective plug according to claim 1 or 2, characterized in that the thermocouple ( 11 ) is formed from a memory alloy. 7. Protective plug according to one of claims 1 to 6, characterized in that the thermocouple ( 11 ) with the second contact bracket ( 9 ) is connected ver. 8. Protective plug according to one of claims 1 to 6, characterized in that the thermocouple ( 11 ) in the second contact bracket ( 9 ) is engaged. 9. Protective plug according to one of claims 1 to 8, characterized in that the contact element ( 1 ) on the first retaining bracket ( 2 ) opposite side of the surge arrester ( 4 ) has at least one resiliently resting on its insulating surface retaining leg ( 12 ).