Field of the invention

The invention relates to an electrical connector system with a cable strain relief member.

Technical background

Electrical connector systems are used to connect various cables, such as for example telecommunication cables, networking cables, other signaling cables or in general any electrical wiring. Electrical connector systems are used for joining electrical circuits, wherein typically a male-ended plug is adapted to connect to a female-ended jack. In many applications the safe coupling of connectors is of high importance. For example, in the case of car safety systems, as e.g. airbag systems in passenger cars, the connectors used for the connection of an airbag to its ignition base have to be provided with reliable safety systems. To ensure that the connectors cannot become loose unintentionally, secondary locking systems are for example used to guarantee the safe mechanical coupling. Often, such secondary locking systems are realized in form of separate plastic components, which can be installed on one of the connectors which are to be secured, or are directly molded on the connector.

Additionally, in many fields of applications, electrical connector systems require cable strain relief members which firmly attach the cables to the connector systems in order to relieve the actual connection portion of the cable from possible strains. This connection portion, where e.g. the cable is dismantled and the cable wiring may be connected to a contact terminal can be particularly fragile and therefore has to be protected. Cable strain relief members are known in the art to relief electrical connector systems from strains applied to a cable. Normally, any forces applied to a cable directly act on the crimp area, i.e. the interconnection where the cable is connected to a contact terminal. These terminals of electrical connectors are usually very small components, such as components that are stamped and/or formed from thin sheet metal material and easily damaged or destroyed by the strain.

An improper seating of a contact terminal in a connector housing may occur if the terminal is not fully inserted therein during the initial assembly of the electrical connector system or if the contact terminal is vibrated or pulled out of its fully seated condition during use of the connector system. Failures of this type are a particular concern in the automotive industry where electrical components are subjected to vibration almost continuously during normal usage. It is therefore known in the art to provide a terminal position assurance (TPA) device for electrical connectors to detect incomplete insertion of contact terminals into the connector housings. They also assure that the contact terminal is properly positioned in the respective housing.

It is an object of the present invention to provide an electrical connector system that reduces the strain on the crimping area and also on the primary and/or secondary lock of connectors systems. It is in particular an object of the present invention to provide an electrical connector system which comprises a minimal number of components and is simple to be mounted. It is a further object to provide an electrical connector system which features terminal position assurance TPA.

These and other objects, which become apparent by reading the following description, are achieved by an electrical connector system according to the subject matter of claim 1.

Summary of the invention

According to the invention, an electrical connector system is provided. The connector system comprises at least one contact terminal, and a

corresponding connector housing. The contact terminal thereby may comprise an insulation crimp and a wire crimp to connect to a cable, and may provide an electrical interface for a corresponding counter connector. The connector housing comprises at least one aperture which is adapted to receive the contact terminal therein. The housing itself may in generally have any shape adapted to connect to the corresponding counter connector. The connector housing may include means for locking the housing to the corresponding counter connector. The electrical connector system further comprises a cable strain relief member separate from the connector housing. Accordingly, the cable strain relief member is not an integral part of the connector housing. The cable strain relief member comprises cable fastening means for fastening the cable strain relief member to a cable for strain relief. Furthermore, the cable strain relief member comprises integrated locking means adapted for locking the member directly to a corresponding counter connector.

The term "counter connector" used herein denotes to any kind of connector adapted to connect to the connector housing and contact terminal provided therein. The counter connector can have suitable means for fixing it to its environment, such as e.g. to a wall of an electrical component, and can provide a respective electrical feed-through there through. The counter connector can further be of any suitable shape, depending on the actual application and design of the connector housing. The counter connector, the connector housing and the cable strain relief member are preferably fabricated by injection molding.

The cable strain relief member is a single, separate member and is adapted to transfer any cable strain directly to the corresponding counter connector. In other words, any pull-out forces applied to the cable are transferred via the cable strain relief member to the counter connector, and not the connector housing. Accordingly, the crimp area of the terminal arranged in the connector housing has to withstand less force due to the fact that the cable strain relief member transfers the force to the counter connector. Advantageously, the present system also relieves any primary locking means of the connector housing to the counter connector and it is applicable in connector systems, where the connector housing cannot be provided with an integrated primary lock, due to e.g. space limitations.

Similarly, the primary and/or secondary lock connecting the contact terminal to the connector housing similarly has to withstand less pull-out since the cable strain relief member transfers the pull-out force to the corresponding counter connector. Thereby, the pull-out force is advantageously not completely acting on the crimp area and the primary and/or secondary lock of the contact terminal. Thereby the life time of the electrical connector system is prolonged.

The term "pull-out force" used herein denotes to any force that is acted so as to pull out a wire or cable from an electrical connector system. Analogous, the term "push-in force" used herein denotes to any force that is acted so as to push in a wire or cable into an electrical connector system.

In a preferred embodiment, the cable strain relief member further comprises mounting means for mounting the member to the connector housing.

This mounting means is preferably a hook adapted to envelope a part of the connector housing when the cable strain relief member is mounted thereto. In one embodiment, this hook has preferably a U-shaped cross-sectional profile.

This mounting means allows for a simple assembly process and advantageously fixes the cable strain member to the connector housing, thereby improving stability of the electrical connector system.

The terms "fastening", "locking", "mounting" and such used herein in connection with different means do not imply a particular application or method, but are merely used to label the different means for clarification. Accordingly, mounting means may generally provide locking functions, for example, and locking means may be used for mounting.

Preferably, the mounting means are adapted to provide terminal position assurance (TPA) when the contact terminal is provided in the at least one aperture of the connector housing and the cable strain relief member is mounted to the connector housing. TPA is known in the art to assure correct positioning of the contact terminal inside the connector housing, thereby reducing the need for time-consuming and costly inspection during assembly.

Preferably, the mounting means for mounting the cable strain relief member to the connector housing provide a lock for the contact terminal to secure the contact terminal in its position in the aperture of the connector housing. The mounting means may thereby function as a primary lock or as a secondary lock for the contact terminal. Preferably, said mounting means include a portion which extends into the connector housing when the cable strain relief member is mounted thereto. This portion is thereby adapted to prevent removal of the contact terminal from its position in the aperture of the connector housing. In other words, the portion locks the aperture of the connector housing such that the contact terminal cannot be removed therefrom.

In a further preferred embodiment, the cable strain relief member is adapted to releasable lock the connector housing to the corresponding counter connector. In other words, the cable strain relief member allows for locking and removing the connector housing to and from the counter connector. Preferably, the cable strain relief member comprises an integrated flexible web which is supporting the integrated locking means adapted for locking the strain relief member directly to the corresponding counter connector. A flexible web may be of any form adapted to provide a restoring force when an external force is applied thereto. Accordingly, the integrated locking means may be provided on the flexible web such that the integrated locking means is shifted or repositioned when a force is applied to the web. Thereby, the flexible web is adapted to release the integrated locking means from the corresponding connector when an external force is applied, e.g. by an operator, to the flexible web. Preferably, the integrated flexible web includes an actuating member. Accordingly, the connector housing with the cable strain relief member can easily be inserted and removed to the corresponding counter connector by applying force to the flexible web thereby interacting with the integrated locking means such that the insertion or removal is not locked or blocked. The actuating member may preferably be actuated by an operator for unlocking the strain relief member from the counter connector. Preferably the actuating member may be actuated by a suitable tool, such as e.g. a screw driver. Accordingly, the skilled person understands that the actuating member is preferably formed such that it can readily be actuated with such a tool, without damaging the actuating member or the strain relief member. Preferably the strain relief member is designed such that its locking function can only be released when applying large external forces thereto. Thus, a resilient connection between the connector housing and the counter connector can be achieved, which cannot be released accidentally.

Preferably the actuating member of the strain relief member is located outside the counter connector when the strain relief member is locked thereto. Accordingly, the actuating member is not encased by the counter connector such that it can be well accessed by an operator for releasing the locking function as described and for removing the connector housing from the counter connector. Hence the releasing of the connector housing from the counter connector can be done in a straightforward manner.

Preferably, the integrated locking means is a locking ramp, which is preferably adapted to engage a corresponding mating part of the corresponding counter connector. Preferably, said mating part is a locking window. In another preferred embodiment, the integrated locking means of the cable strain relief member is a locking window and the mating part of the corresponding counter connector is preferably a locking ramp. The locking ramp is in both cases adapted to lower the flexible web of cable strain relief member when the connector housing with mounted cable strain relief member is inserted into the

corresponding counter connector during assembly of the electrical connector system. Once inserted, the locking ramp face, which defines a normal to the direction of insertion, provides the locking function. Accordingly, the interplay of a locking ramp and a corresponding locking window allows for an easy assembly of the electrical connector system.

Also the integrated locking means may preferably be actuated by an operator for unlocking the strain relief member from the counter connector, for example by means of a suitable tool, such as e.g. a screw driver. Preferably the strain relief member is adapted to be unlocked from the counter connector when an external force is applied to the integrated locking means of the strain relief member. Preferably, said external force is thereby applied in mating direction of the connector system, i.e. the direction of insertion or removal of the connector housing to or from the counter connector. Preferably the integrated locking means are thereby accessed from outside the counter connector through a respective opening provided therein, wherein such an opening is preferably provided in mating direction of the connector system. Thereby the locking function can be released from the opposite side of insertion or removal, i.e. from "inside" the connector housing, as the integrated locking means are reachable from inside the counter connector, even though the connector housing is arranged in the counter connector.

In another preferred embodiment of the present invention, the contact terminal comprises primary locking means, which are adapted to lock the contact terminal in the aperture of the connector housing. Preferably, said primary locking means is a latching lance which allows for easy insertion of the contact terminal into the connector housing and lock the contact terminal therein.

Preferably, the connector housing may also comprise locking means, which are adapted to provide a primary lock for the connector housing to the corresponding counter connector.

In a further preferred embodiment the cable strain relief member comprises a spacer which is adapted to separate the cable from connector housing when the system is fully mounted, i.e. when the cable is connected to the contact terminal, which in turn is inserted into the aperture of the connector housing, and the cable strain relief member is fastened to the cable. The spacer, provided between the cable and the connector housing, advantageously protects the crimping area when for example the cable is forced or pushed further into the connector housing. The spacer preferably comprises two surfaces, wherein one of the surfaces is adapted to be in contact with the connector housing while the other surface is adapted to be in contact with a cable sheeting of the cable. Hence, when the cable is pushed, the force is preferably transferred via the spacer to the connector housing, thereby advantageously reducing strain on the crimp area.

The person skilled in the art understands that the system may preferably further comprise a corresponding counter connector which may be any connector that is compatible with the connector housing a contact terminal positioned therein, and a cable strain relief member mounted to the connector housing. Preferably, the corresponding counter connector is adapted to interact with the integrated locking means of the cable strain relief member to provide cable strain relief. Preferably the counter connector comprises an opening enabling to apply an external force in mating direction of the connector system to the strain relief member, and in particular to the integrated locking means of the strain relief member, for unlocking the strain relief member from the counter connector. Said opening may be provided on the counter connector in mating direction of the connector system and is preferably separate from the aperture of the counter connector and may be provided on an opposing side of the counter connector with respect to said aperture. Accordingly, the locking function can easily be released by e.g. inserting a screw driver through said opening and by applying a respective force to the strain relief member with said screw driver. Preferably the connector housing and/or the counter connector feature a respective groove or path allowing for guiding a respective tool for applying said force in mating direction to the strain relief member for unlocking the locking function.

Preferably the connector housing comprises a rib adapted to interact with the counter connector for preventing a further insertion of the connector housing into the counter connector when the strain relief member is locked to the counter connector. Preferably the aperture of the counter connector is step-like shaped, wherein a first step of the step-like shaped aperture is adapted to interact with such a rib of the connector housing for preventing a further insertion as described. Accordingly, when the connector housing is inserted into the aperture of the counter connector far enough, such that the integrated locking means of the strain relief member are locking the member to the counter connector, the rib comes into blocking contact with the first step of the step-like shaped aperture such that further insertion forces, or push-in forces are transferred via said blocking contact to the counter connector. Hence the contact terminal is protected.

Further, the system may preferably comprise a cable mounted to the contact terminal, wherein the mounting may comprise any means known to the skilled person to attach the cable to the contact terminal. For example, an insulation crimp to connect the contact terminal to an insulation of the cable and a wire crimp to connect the contact terminal to a wiring of the cable may be utilized for connecting the cable to the contact terminal. The cable may include one or more wires and the insulation may be any insulation known by the skilled person.

Description of preferred embodiments

In the following the invention is described exemplarily with reference to the enclosed figures.

Fig. l is a schematic illustration of an electrical connector system, according to the present invention. Fig. 2 shows a three-dimensional cross-section of Fig. l.

Fig. 3 is a schematic illustration of a cable strain relief member according to the present invention.

Fig. 4 shows the cable strain relief member of Fig. 3 from a different perspective.

Fig. 5 is a schematic illustration of an electrical connector system according to the present invention.

Fig. 6 shows a three-dimensional cross-section of Fig. 5.

Fig. 1 shows a perspective view of an electrical connector system in accordance with the invention. In Fig. 2, the electrical connector system of Fig. 1 is shown in a three-dimensional cross-section. As one can see in Figs. 1 and 2, the illustrated electrical connector system comprises a connector housing 20, which in turn comprises at least one aperture adapted to receive a contact terminal 40 therein. The contact terminal 40 may comprise an insulation crimp and a wire crimp for mounting a cable 30 to the contact terminal 40. It will be appreciated that any suitable means may be utilized to mount the cable 30 to the contact terminal 40. This interface 42 between the cable and the contact terminal is denoted as "crimping area" or "crimp area" herein. The contact terminal 40 further comprises primary locking means 41, which provides a primary lock for the contact terminal 40 to secure said contact terminal 40 in its position in the aperture of the connector housing 20. The primary locking means 41 may comprise a latching lance. The skilled person understands that any means may be utilized to provide the primary locking function. During assembly of the system, the latching lance 41 latches with the terminal housing 20 when the contact terminal 40 is fully inserted into the aperture of the housing 20, thereby allowing for an easy assembly.

The electrical connector system further comprises a cable strain relief member 10 which is a separate component from the connector housing 20. The cable strain relief member 10 comprises integrated locking means 12 which are adapted for locking the member 10 directly to a corresponding counter connector 50. As illustrated, the integrated locking means 12 is preferably a locking ramp. The locking ramp features an insertion ramp face, or ramp wedge, which faces into the direction of insertion during assembly of the system. The locking ramp further features a locking ramp face perpendicular to the direction of insertion and facing into the opposed direction of insertion. However, the locking means 12 may also be of other shapes, such as e.g. block-shape. The locking means 12 is supported by a flexible web 15 which in turn includes an actuating member 14. The flexible web 15 is adapted to release the integrated locking means 12 from the corresponding counter connector 50 when an external force is applied to the flexible web 15. Similarly, the flexible web 15 may be adapted to allow for an easy insertion of the illustrated electrical connector system into a corresponding counter connector 50 when an external force is applied to the flexible web 15. The cable strain relief member 10 further comprises fastening means 11 for fastening the strain relief member 10 to the cable 30 for strain relief. It will be appreciated that the fastening means 11 is only sketched in the figures and that any means for fastening the cable strain relief member 10 to the cable 30 may be utilized. For example, the cable strain relief member 10 may be clamped, squeezed or glued to the cable 30. Alternatively, a snap-lock system may be applied or a metal sleeve may be utilized for coupling the cable 30 to the cable strain relief member 10, for example. The cable 30 in turn comprises a cable sheathing 31 and a wiring 32. It will be appreciated that the wiring 32 may consist of or more wires and that the present invention is not restricted to any particular sort or kind of cable sheathing.

As can further be seen from Figs. 3 and 4, the cable strain relief member 10 of Figs. 1 and 2 also comprises mounting means 13a, 13b for mounting the cable strain relief member 10 to the connector housing 20. The mounting means 13a, 13b thereby allow for securing the position of the cable strain relief member 10 to the connector housing 20. The mounting means 13a, 13b may be adapted to fit into corresponding means, such as protrusions, apertures or clearances of the connector housing 20. As illustrated, the mounting means 13a, 13b may comprise at least one hook 13a adapted to envelope a part of the connector housing 20. Preferably, the mounting means has preferably a U-shaped cross sectional profile such that the mounting means 13a, 13b can envelope a part of the connector housing 20. This allows for an easy fixation during the mounting of the cable strain relief member 10 to the connector housing 20 during assembly of the electrical connector system.

As can be seen from Figs. 2, the mounting means 13a also provide terminal position assurance TPA. Accordingly, mounting the cable strain relief member 10 to the connector housing 20 indicates that the pre-inserted contact terminal 40 is in correct position inside the connector housing 20, reducing the need for any costly and expensive inspection during assembly.

The mounting means 13a may further provide a secondary lock 13a for the contact terminal 40. Accordingly, when the primary locking means 41 of the contact terminal 40 fails, the secondary lock 13a hinders the contact terminal 40 from dropping out of the connector housing 20. As can be seen in Fig. 1, the mounting means 13a includes a portion extending into the connector housing 20 which in turn blocks the aperture of the connector housing 20. Preferably the contact terminal 40 is of such shape that it gets stuck in the blocked aperture of the connector housing 20 and cannot be removed when the cable strain relief member 10 is mounted to the housing 20.

Accordingly, the mounting means 13a of the electrical connector system of Figs. 1 and 2 provide three functions in one single piece, namely fixation of the cable strain relief member 10 to the connector housing 20 and thus a locking of the connector housing 20 to the counter connector 50, a TPA functionality, and a secondary locking function for the contact terminal 40. It will be appreciated that a single portion may comprise all these functions, or that separate portions of the cable strain relief member 10 may provide one or more of these functions separately.

The electrical connector system of Figs. 1 and 2 is adapted to be locked to the corresponding counter connector 50 only by means of the locking means 12, since the connector housing 20 shown does not in itself have any (primary) locking means. However, it will be appreciated that the connector housing 20 may itself include integrated means for locking the housing 20 to the counter connector 50 - as known in the art - in which case the locking means 12 of the cable strain relief member 10 provide a secondary lock for the connector housing 20.

Figs. 5 and 6 show an electrical connector system, where the electrical connector system of Figs. 1 and 2 is connected to a corresponding counter connector 50. The counter connector 50 can have any desired and suitable shape. A contact pin 60 of the counter connector 50 is e.g. in electrical contact with the contact terminal 40, which provides electrical contact to the wiring 32 of the cable 30. The counter connector 50 comprises a locking window 51 which is adapted to receive the locking ramp 12 of the cable strain relief member 20. Besides, it will be appreciated that the counter connector 50 may comprise a locking ramp and the cable strain relief member 20 comprises a locking window adapted to receive the locking ramp of the counter connector 50 instead. As can be seen from Fig. 6 in detail, the strain relief member 10 provides strain relief for the crimp area 42 and the primary lock 41 of the contact terminal 40. In particular, when a pull-out force is applied to the cable 30, the pull-out force is transferred via the fastening means 11 and locking means 12 of the cable strain relief member 10 directly to the corresponding counter connector 50. Hence the crimp area 42 and the primary lock 41 of the contact terminal 40 have to withstand less pull-out force.

Further on, the cable strain relief member 10 includes a flexible web 15, which supports the integrated locking means 12 and includes an actuating member 14. The flexible web is 15 formed to provide a restoring force

perpendicular to the direction of insertion or removal of the connector housing 20 with mounted cable strain relief member 10 into or from the corresponding counter connector 50, when a force is applied to the flexible web 15. In general, an operator can insert or remove the connector housing 20 with mounted cable strain relief member 10 into the corresponding counter connector 50 by applying force to the flexible web 15 such that the web 15 bows and the integrated locking means 12 supported by the web 15 is lowered. Preferably, as illustrated, the integrated locking means 12 is a locking ramp. Accordingly, once the connector housing 20 with mounted cable strain relief member 10 is inserted into the corresponding counter connector 50, the flexible web 15 bows as a result, such that the locking ramp 12 can access the corresponding window 51 in the counter connector 50 to provide the locking function. This allows for an easy assembly of the electrical connector system.

By pressing on the actuating member 14, which is preferably located outside the counter connector 50 as illustrated in Fig. 5, an operator can unlock the integrated locking means 12. By applying a force to the flexible web 15, the locking ramp 12 is lowered such that it is not in locking contact with the corresponding counter connector 50 any longer. This allows for extracting the connector housing 20 with mounted strain relief member 10 from the

corresponding counter connector 50 simply by applying a force on the flexible web 15 by e.g. pressing on the actuating member 14 and by pulling for example the cable 30. Accordingly, the connector housing 20 with mounted strain relief member 10 can simply be extracted from counter connector 50 in a nondestructive way. Again, the cable strain relief member 10 reduces the force acting on the crimp area 42, by transferring the pull-out force during the disassembly via the fastening means 11 and the mounting means 13a, 13b directly to the connector housing 20. Thereby, the fragile crimping area is protected.

As illustrated in Figs. 2 and 5, the cable strain relief member 10 further includes a spacer 16. The spacer 16 is located between the cable sheathing 31 and the connector housing 20 and comprises two surfaces 17a, 17b. One surface 17a is in contact with the connector housing 20, while the other surface 17b is in contact with the cable sheathing 31. When pushing the cable 30 mounted to the contact terminal 40 provided in the connector housing 20 into the corresponding counter connector 50, the push-in force is transferred via the spacer 16 directly to the connector housing 20. Thereby, the push-in force acting on the crimp area 42 is reduced. Accordingly, the spacer 16 may reduce an overstraining of the crimping area during assembly of the electrical connector system.

Upon inserting the connector housing 20 and the mounted cable strain relief member 10 into the counter connector 50, the locking ramp 12 interacts with the counter connector 50 such that the flexible web 15 is lowered. When the connector housing 20 with the mounted cable strain relief member 10 is fully inserted into the corresponding counter connector 50, the locking ramp snaps 12 into locking position, i.e. in the window 51 of the counter connector 50, due to the restoring forces of the flexible web 15. The actuating member 14 may be adapted to prevent further insertion of the connector housing 20 with mounted cable strain relief member 10 into the counter connector 50, thereby preventing an overstraining of the crimp area 42.

According to one particular aspect of the present invention, the locking means 12 can be assessed from "inside" the counter connector 50: With reference to Fig. 6, the skilled person will appreciate that a channel 61 (indicated by dashed lines) could easily be provided in the counter connector 50 that runs from the left hand side in mating direction to e.g. the window 51. Such a channel 61 would allow the insertion of e.g. a screw driver from the left side of Fig. 6, to eventually urge the locking means 12 downwards for releasing the locking function. The ramp-like shape of the locking means 12 is hence particularly preferred in this respect, as it allows for flexing the web 15 by actuating the locking means 12 in mating direction of the system. The skilled person will understand that the channel 61 indicated in Fig. 6 is only provided for illustrate purposes and that in practice the channel 61 would probably need to be of larger dimension to allow a smooth insertion of a tool therein. This can easily be achieved by e.g. enlarging the respective wall thickness of the counter connector 50 in the portion comprising the channel 61.