DE20009788U1 - Connector for connecting electrical cables to a Leipterplatte - Google Patents

Description

PATENT ATTORNEYS

DIPL.-ING. WOLFRAM WATZKE (- 1999)

DIPL-ING. ULRICH CHRISTOPHERSEN

DIPL-ING. WOLFGANG BRINGMANN

Stocko Contact GmbH & Co. KG patent attorneys

Simonshöfchen 31 European patent attorneys

D-42327 Wuppertal

Our number 00-0589

Our ref.

Your reference Your ref.

_n . 30 May 2000

Date

Connector for connecting electrical cables to a Circuit board

The invention relates to a connector, in particular a zero-force connector, for connecting electrical lines to a printed circuit board.

Connectors are known for a wide range of applications. They are therefore used in a wide variety of designs and usually in large quantities, for example in the area of so-called "brown goods", and are subject to a wide range of requirements with regard to their respective use. In addition to simple and cost-effective production, low installation height, high holding forces or fully automatic assembly, strain relief or reliable contact must also be provided. In addition, connectors known as zero-force or ZIF connectors (zero insertion force) are known, which must be designed in such a way that no significant pressure or tensile forces occur during a plugging or unplugging process.

In connection with printed circuit boards, a distinction must be made between two types of connection with regard to the design of the connectors. Direct plugging, in which a connector is plugged onto a printed circuit board in such a way that the contact elements of the connector are in direct contact with the printed conductors of a printed circuit board, and indirect plugging, in which a connector designed as a two-part plug connection is used, one of which

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Part is mounted on the circuit board and the other part is attached to the electrical line. Although the present invention is primarily aimed at connectors for indirect plugging, it can also be used for direct plugging with minor modifications, which generally requires a special design of the circuit board.

In the context of the present invention, a printed circuit board or circuit board is understood to mean printed circuits with conductor patterns on one or both sides as well as multilayer printed circuit boards.

Such circuit boards are usually provided with metalized holes for attaching components using soldered connections or press-fit connections. The components, for example the part of a connector for indirect plugging that is to be arranged on the circuit board, have contact elements for this purpose that are designed as contact legs in their connection area on the circuit board side, which are inserted into the holes in the circuit board. When soldering, for example using soldering processes such as wave soldering, the contact legs are soldered to the underside of the circuit board, whereas when pressed in, the contact legs are elastically deformable or rigid press-fit pins that create a solder-free electrical connection that also reduces mechanical stress.

This through-hole technology, which is generally well suited to the manual assembly of components on a circuit board, requires a relatively large amount of space for the connections, so that SMT technology (Surface Mounted Technology) is increasingly being used, in which surface-mountable components, generally referred to as SMD (Surface Mounted Devices), are applied with solderable contact elements directly to connection points, so-called solder pads, on the surface of the circuit board. The solder pads usually consist of a defined layer of solder and are soldered by heating the entire unit, i.e. the circuit board equipped with the components. In addition to the electrical contact, this also provides mechanical fastening without the need to

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This not only allows for shorter assembly times but also significantly higher packing densities on the circuit board and thus the miniaturization that is commonly sought after.

In the prior art, connectors for connecting electrical cables to a circuit board are known, which have a housing made of plastic or metal, which primarily serves to mechanically protect the components of a connector and to protect against contact with electrical parts. Depending on the design, the housing can also be used for other functions, such as locking, polarization, coding, electrical shielding, sealing or strain relief. Electrical cables include cables with one or more wires, with insulating sleeves, a sheath to protect structural elements or screens for shielding, in particular flexible cables, flat cables, hose cables, shielded cables or coaxial cables, as well as cables that are suitable for fixed installation and have a sheath made of plastic or rubber and possibly an additional sheath made of metal.

The disadvantage of the known connectors is the relatively complex method used to achieve strain relief. The complicated and unreliable contacting of the electrical cables is also unsatisfactory.

The invention is based on the object of providing a connector for connecting electrical lines to a circuit board, with which reliable strain relief and reliable contacting of the electrical line can be achieved in a comparatively simple manner.

This object is achieved according to the invention by a connector of the type mentioned at the outset, which consists of a housing which can be fastened to the circuit board and which is provided on one end with

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is provided with spaced-apart windows and serves in these areas as a contact carrier for receiving contact elements, and an insertion element which can be inserted into an opening in the housing opposite the windows, which can be locked in a first securing position and a second end position in the housing and has a support surface which positions the electrical line and is provided with a recess, wherein the electrical line can be clamped between the support surface and a clamping element which can be locked onto the insertion element and on which at least one projection engaging in the recess is arranged, and wherein the insulation-free end of a wire of the electrical line contacts a plug-in area of an individual contact element located in the housing in the end position of the insertion element inserted into the housing and a connection area of the contact element which can be led out of the windows can be electrically conductively connected to a conductor track of the circuit board.

Such a connector is based on the knowledge that reliable strain relief can be achieved when a projection arranged on the clamping element engages in the recess of the insertion element. In this way, the electrical conductor clamped between the insertion element and the clamping element is also pressed into the recess and thereby additionally fixed in a form-fitting manner. Reliable contacting of the electrical line is also contributed to by the fact that the insertion element can initially be locked in a securing position in the housing before it reaches the end position in the housing by further insertion, in which the contact elements are then contacted. Since contacting only takes place when the insertion element and housing are already joined together, in addition to targeted and always consistent contacting of the contact elements, effective contact protection of the electrical line, which may already be live when the contact is made, is also ensured.

In order to be able to position the electrical cable comfortably on the support surface of the insert element, it is advisable to

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The insert element and the clamping element are designed as separate components or are connected to one another via a film hinge. It is also useful to provide the insert element with guide surfaces for the electrical cable on both sides of the support surface. This ensures precise positioning of the electrical cable on the support surface. For this purpose, it is also advantageous if the insert element has at least one cam which engages positively in a recess in the electrical cable. This makes it possible in particular to precisely define the position of the free end of the electrical cable on the insert element, so that pressing the electrical cable into the recess by the projection has no influence on the positioning of the electrical cable on the support surface. The cam or cams can be arranged either on the guide surfaces or at any point on the support surface. The latter can generally only be achieved, however, if the loss of one or more wires is accepted.

The insertion element is advantageously provided with first and second locking lugs arranged one behind the other in the plug-in direction, which can be fixed to a correspondingly designed fastening section of the housing to lock the insertion element in the safety position and end position. This represents a simple and therefore cost-effective design in terms of construction. It has also proven advantageous to design the fastening section to be spring-loaded perpendicular to the plug-in direction of the insertion element. The flexibility of the fastening section achieved in this way means that the insertion element can be inserted into the housing with almost no resistance, thus forming a zero-force connector.

According to a particularly advantageous development of the connector according to the invention, the clamping element is provided with an inclined run-on surface on its front face in the plug-in direction, which, at a distance from the support surface in the end position of the insertion element, presses the plug-in area of a contact element down onto the associated insulation-free wires of the electrical line. This design ensures that

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on the one hand, the contact elements are only contacted in the end position of the insertion element and on the other hand, the insulation-free wires of the electrical cable are reliably contacted.

In a further advantageous embodiment of the plug connector, the support surface can alternatively or additionally be provided with a slot that accommodates the free end of the electrical line, whereby in the end position of the insertion element, the plug-in area of a contact element contacts the associated insulation-free wire of the electrical line in the area of the slot. In this embodiment, the slot easily defines an exact position of the contact surface between the insulation-free wires of the electrical line and the contact elements, thus promoting reliable contact. In a further development of the plug connector, it is also proposed to provide a stop for the electrical line guided through the slot on the underside of the insertion element facing away from the clamping element. Such a development allows a contact clearance between the contact elements and the electrical line to be set in a targeted manner. By dimensioning the length of the section of the electrical line inserted through the slot in such a way that the insulation-free wires of the electrical line are slightly lifted off the support surface in the area of the slot by the free end of the electrical line resting on the stop, the distance to the contact elements can be varied.

With regard to reliable strain relief and secure form-fitting, it is advantageous if the projection has a rectangular, triangular or rounded cross-section, depending on the electrical cable used. The recess of the insertion element can also be designed differently to suit the respective application, for example as a continuous opening or a trough-shaped recess. The contact elements are expediently designed in their plug-in area as a spring-loaded fork contact, which has an essentially hook-shaped contact holder for locking in the housing. This enables secure fastening with simple assembly.

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of the contact elements in the housing, even if the connection area of the contact elements is pressed down onto the electrical line by the contact surface. It is also useful if the contact elements have a leg in their plug-in area that is provided with a curvature that, in the end position, engages in a correspondingly formed recess on the insertion element. Such a design offers the advantage that, on the one hand, additional locking of the insertion element in the housing is achieved and, on the other hand, the reaching of the end position is indicated both acoustically and haptically. The curvature can be either convex or concave on the leg. In the latter case, a correspondingly shaped projection is provided on the insertion element in place of the recess.

Depending on the application, it is also useful to provide the contact elements in their connection area with straight or angled contact legs that are pressed into the circuit board or soldered to it in order to ensure a permanent electrical connection to the circuit board in the case of such a vertical or horizontal connector.

Finally, it is proposed to design the housing as an insulating body so that additional means to insulate the individual contact elements are unnecessary.

Details and further advantages of the objects of the present invention emerge from the following description of preferred embodiments. In the accompanying drawings show in detail:

Fig. 1 is an exploded view of a connector connected to a flat cable in a first embodiment;

Fig. 1a is a perspective view of a connector in a second embodiment;

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Fig. 1 b is a perspective view of a connector in a third embodiment;

Fig. 2 is an exploded view of a connector connected to a flat cable in a fourth embodiment;

Fig. 2a is an exploded view of a connector connected to a flat cable in a fifth embodiment;

Fig. 3 is a perspective view of the connector according to Fig. 2 arranged on a printed circuit board;

Fig. 3a is a sectional view of the connector according to Fig. 3;

Fig. 4 is a perspective view of the connector according to Fig. 2a arranged on a printed circuit board;

Fig. 4a is a sectional view of the connector according to Fig. 4;

Fig. 4b is a perspective view of an insertion element of the connector according to Fig. 4;

Fig. 5 is a sectional view of a first variant of a clamping element fixed on an insertion element in the region of a projection engaging in a recess;

Fig. 5a is a sectional view of a second variant according to Fig. 5;
Fig. 5b is a sectional view of a third variant according to Fig. 5;
Fig. 5c is a sectional view of a fourth variant according to Fig. 5;

Fig. 6 is a side view of a contact element and a plug-in element and

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Fig. 6a is a sectional view showing the contact element and the insertion element according to Fig. 6 in a locked state.

The connector shown in Fig. 1 has a housing 10 designed as an insulating body, which can be fastened to a printed circuit board 50.

The housing 10 is provided with windows 11 spaced apart from one another on one end face and with an opening 12 on the opposite side. In the area of the windows 11, the interior of the housing 10 is designed as a contact carrier for receiving contact elements 60, the connection area of which is led out of the windows 11 in order to be electrically connected to conductor tracks 51 of the circuit board 50. The contact elements 60 are designed as a spring-loaded fork contact and have hook-shaped projections on their upper leg 62 as contact holders 61, which are locked into a section of the upper inner surface 15 of the housing 10 facing the windows 11, as can be seen in Fig. 3a and 4a.

In the opening 12 is an insert element 20, which provides a flat support surface

21 for a flat cable 40. The insertion element 20 is provided with a recess extending across the support surface 21

22. On both sides of the support surface 21 there are guide surfaces 23 for the flat cable 40 and cams 24 which, when the flat cable 40 is positioned on the support surface 21, engage in a form-fitting manner in recesses 42 provided therein. On the outside of the guide surfaces 23 there are two locking lugs 25, 26 arranged one behind the other in the plug-in direction of the insert element 20. When the insert element 20 is inserted into the housing 10, the locking lugs 25, 26 interact with fastening sections 13 arranged on both sides of the opening 12. The locking lugs 25 lock the insert element 20 in a first securing position I in the housing 10. The locking lugs 26, on the other hand, fix the insert element 20 in a second end position II on the housing 10. In the end position II, stop surfaces 29 extending orthogonally to the guide surfaces 23, which are arranged on the outside of the insertion element 20, come to rest on the housing 10, so that a continued insertion of the insertion element 20

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is excluded. The fastening sections 13 are designed to be spring-loaded perpendicular to the direction of insertion of the insertion element 20, whereby the insertion element 20 can be inserted into the locking position I and end position II with almost no resistance. The connector is therefore a zero-force or ZIF connector.

A clamping element 30 is pivotably arranged on the insertion element 20 by means of a film hinge 32. The clamping element 30 is provided on its side opposite the film hinge 32 with a latching hook 34 which, when the clamping element 30 is pivoted over the insertion element 20, can be locked into place on the side of the insertion element 20 opposite the film hinge 32 in order to clamp the flat cable 40 positioned on the support surface 21 between the insertion element 20 and the clamping element 30. A projection 31 is formed on the clamping element 30 which engages in the recess 22 when the clamping element 30 is pivoted over the insertion element 20. The flat cable 40 positioned on the support surface 21 is also pressed into the recess 22 and deformed into a fold 43. This results in high holding forces and reliable strain relief.

The clamping element 30 is also provided on its front end in the plug-in direction with an inclined run-on surface 33 which runs parallel to the projection 31 and, when the clamping element 30 is pivoted over the insertion element 20, extends at a distance from the flat cable 40 positioned on the support surface 21. As can also be seen in Fig. 3a, when the insertion element 20 is inserted into the housing 10, the run-on surface 33 runs onto an insertion bevel 14 formed above the opening 12 of the housing 10 shortly before reaching the end position II, which forces the run-on surface 33 between the inner surface 15 and the plug-in area of the contact elements 60 located inside the housing 10.

This results in the upper leg 62 of the contact elements 60 being pressed down in the end position II onto an associated wire 41 of the electrical cable 40 which is free of insulation in the contact area. Thus, the electrical contacting of the flat cable 40 only takes place in the end position II.

whereas effective contact protection is guaranteed as soon as safety position I is reached.

As can be seen in Fig. 6 and 6a, the contact elements 60 have a curvature 64 on their lower leg 63. The underside of the insertion element 20 is provided with a recess 64a corresponding to the curvature 64. The arrangement of the curvature 64 on the leg 63 or of the recess 64a on the insertion element 20 is such that in the end position II of the insertion element 20 inserted into the housing 10, a locking of the contact elements 60 and the insertion element 20 takes place, which contributes to secure contact. In addition, it is perceptible in this way both acoustically and haptically when the insertion element 20 reaches the end position II.

The connector shown in Fig. 1 is designed as a surface-mountable component (SMD) and can therefore be processed using so-called "pick-and-place technology". Figs. 1a and 1b show alternative embodiments in which the connection area of the contact elements 60 has straight or angled contact legs that are pressed or inserted and soldered into metallized holes in the circuit board 50. In the embodiment according to Fig. 1b, the windows 11 also extend on the underside of the housing 10 in order to be able to provide a grid dimension that corresponds to the respective application.

The embodiment shown in Fig. 2 differs from the connector according to Fig. 1 only in that the insertion element 20 and the clamping element 30 are not connected to one another via a film hinge, but are designed as separate components. In order to fix the clamping element 30 to the insertion element 20 in a locking manner in this case, the clamping element 30 is provided with recesses 35 into which correspondingly designed locking hooks 34a on the insertion element 20 engage when the clamping element 30 is arranged on the insertion element 20, as well as

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Fig. 3 and 3a also show such a connector.

In comparison, the further embodiment of a connector shown in Fig. 2a and 4 to 4b lacks the run-up surface 33.

Instead, the support surface 21 of the insert element 20 is provided with a slot 27 which receives the free end of the flat cable 40 and thus defines a precise position of the contact surface between the flat cable 40 and the contact elements 60, as can be seen particularly clearly in Fig. 4a and 4b. For the flat cable 40 guided through the slot 27, a stop 28 is also formed on the underside of the insert element 20 facing away from the clamping element 30. This has the consequence that, due to the clamping locking of the flat cable 40 between the insert element 20 and the clamping element 30, depending on the length of the section of the flat cable 40 pushed through the slot 27, the insulation-free wires 41 in the area of the slot 27 are slightly lifted off the support surface 21 in the end position II and thus form a specifically variable contact surface for the upper leg 62 of the contact elements 60. Furthermore, the position of the slot 27 on the support surface 21 allows the contact surface to be determined independently of the end position determined by the interaction of the locking lugs 25, 26 with the fastening sections 13. This is of use, for example, if differently designed contact elements 60, such as those shown in Figs. 1a and 1b, are to be used without changing the housing 10. A universal design of the insert element 20 can thus be achieved if several slots 27 are arranged parallel one behind the other in the support surface 21.

Finally, Fig. 5 to 5c show different possibilities for the design of the projection 31 and the recess 22 receiving it. With regard to reliable strain relief and secure form-fitting, several projections 31 can be provided, for example, as can be seen in Fig. 5b and 5c. The projection 31 can also be provided with different cross-sectional shapes, for example

rectangular as in Figs. 3a and 4a or triangular as in the above-mentioned figures. In addition, the recess 22 of the insertion element 20 can also be designed differently and, depending on the respective application, can be, for example, a continuous opening as in Figs. 3a, 4a and 5 or a trough-shaped recess as in Figs. 5a to 5c.

The connector described above is particularly suitable for use as a zero-force connector. In addition to reliable contact and effective contact protection, the connector is also characterized by high holding forces and reliable strain relief. Depending on the design, it is suitable for both conventional through-hole technology and the increasingly popular SMT. Last but not least, it enables the processing of different electrical cables 40 in one and the same housing and thus also offers the creation of jumpers.

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List of reference symbols

10 Housing 33 Ramp surface 11 Window 34 Latching hook 12 opening 34a Latching hook 5 13 Fastening section 35 Recess 14 Insertion bevel 36 Flat cable 15 Inner surface 37 Vein 16 Insert element 38 Recess 17 Support surface 39 Fold 10 18 Recess 40 Circuit board 19 Guide surface 41 Conductor track 20 cam 21 locking lug 42 Contact element 22 locking lug 43 Contact holder 15 23 slot 44 upper thigh 24 attack 45 lower thigh 25 Stop surface 46 Curvature 64a Recess 26 Clamping element 27 head Start I Securing position 20 28 Film hinge The End position

Claims (14)

1. Plug connector, in particular zero-force plug connector, for connecting electrical lines ( 40 ) to a circuit board ( 50 ), comprising a housing ( 10 ) which can be fastened to the circuit board ( 50 ), which is provided on one end face with windows ( 11 ) spaced apart from one another and serves in these areas as a contact carrier for receiving contact elements ( 60 ), and an insertion element ( 20 ) which can be inserted into an opening ( 12 ) of the housing ( 10 ) opposite the windows ( 11 ), which can be locked in a first securing position (I) and a second end position (II) in the housing ( 10 ) and has a support surface ( 21 ) which positions the electrical line ( 40 ) and is provided with a recess ( 22 ), wherein the electrical line ( 40 ) is between the support surface ( 21 ) and a recess (22) provided on the insertion element ( 20 ). can be clamped in a locking manner by means of a clamping element ( 30 ) on which at least one projection ( 31) engaging in the recess (22 ) is arranged, and wherein the insulation-free end of a wire ( 41 ) of the electrical line ( 40 ) contacts a plug-in area of an individual contact element ( 60 ) located in the housing ( 10 ) in the end position (II) of the insert element ( 20 ) inserted into the housing ( 10 ), and a connection area of the contact element ( 60 ) that can be led out of the windows ( 11 ) can be electrically conductively connected to a conductor track ( 51 ) of the circuit board ( 50 ). 2. Connector according to claim 1, characterized in that the insertion element ( 20 ) and the clamping element ( 30 ) are designed as separate components or are connected to one another via a film hinge ( 32 ). 3. Connector according to claim 1 or 2, characterized in that the insertion element ( 20 ) is provided on both sides of the support surface ( 21 ) with guide surfaces ( 23 ) for the electrical line ( 40 ). 4. Connector according to one of claims 1 to 3, characterized in that the insertion element ( 20 ) has at least one cam ( 24 ) which engages in a form-fitting manner in a recess ( 42 ) of the electrical line ( 40 ). 5. Plug connector according to one of claims 1 to 4, characterized in that the insertion element ( 20 ) is provided with first and second locking lugs ( 25 , 26 ) arranged one behind the other in the plugging direction, which can be fixed to a correspondingly designed fastening section ( 13 ) of the housing ( 10 ) for locking the insertion element ( 20 ) in the securing position (I) and end position ( 11 ). 6. Connector according to claim 5, characterized in that the fastening section ( 13 ) is designed to be resilient perpendicular to the plug-in direction of the insertion element ( 20 ). 7. Connector according to one of claims 1 to 6, characterized in that the clamping element ( 30 ) is provided on its front end in the plugging direction with an inclined run-on surface ( 33 ) which, at a distance from the support surface ( 21 ), presses the plug-in area of a contact element ( 60 ) onto the associated insulation-free wires ( 41 ) of the electrical line ( 40 ) in the end position (II) of the insertion element ( 20 ). 8. Connector according to one of claims 1 to 7, characterized in that the support surface ( 21 ) is provided with a slot ( 27 ) receiving the free end of the electrical line ( 40 ), wherein in the end position (II) of the insertion element ( 20 ) the plug-in region of a contact element ( 60 ) contacts the associated insulation-free wire ( 41 ) of the electrical line ( 40 ) in the region of the slot ( 27 ). 9. Connector according to claim 8, characterized in that a stop ( 28 ) for the electrical line ( 40 ) guided through the slot ( 27 ) is provided on the underside of the insertion element ( 20 ) facing away from the clamping element ( 30 ). 10. Connector according to one of claims 1 to 9, characterized in that the projection ( 31 ) has a rectangular, triangular or rounded shape in cross section. 11. Connector according to one of claims 1 to 10, characterized in that the contact elements ( 60 ) are designed in their plug-in area as a resilient fork contact which has a substantially hook-shaped contact holder ( 61 ) for locking in the housing ( 10 ). 12. Connector according to one of claims 1 to 11, characterized in that the contact elements ( 60 ) have a leg ( 63 ) in their plug-in area, which is provided with a curvature ( 64 ) which, in the end position (II), engages in a correspondingly formed recess ( 64a ) on the insertion element ( 20 ). 13. Connector according to one of claims 1 to 12, characterized in that the contact elements ( 60 ) are provided in their connection area with straight or angled contact legs which are pressed into the circuit board ( 50 ) or soldered to it. 14. Connector according to one of the preceding claims, characterized in that the housing ( 10 ) is designed as an insulating body.