Connector with secondary latching and with a lateral cable outlet

[0003] The invention relates to a connector with secondary latching.

[0004] Connectors of this kind are used e.g. in the motor industry in order to produce electric connections which meet exacting requirements. The requirements relate on the one hand to the reliability with which such a connection must be made and on the other hand to protection against inexpert handling of the connector. The secondary latching is designed to ensure that when the latch closure has engaged, its position is subsequently secured so that the connection cannot be accidentally broken, e.g. by pulling the connection cable in question. On the other hand the secondary latching can be designed so that it also engages and can subsequently be released by hand or only with a special tool. This prevents unauthorised opening. These requirements apply particularly to passenger-retaining systems in motor vehicles, where the connector connects the trigger of an airbag propelling charge, e.g. in the impact cup of a steering wheel, to the vehicle power circuit. During assembly of conventional connectors of this kind, problems occur regarding clear recognition of the state in which the connector is in during assembly. In other words sometimes the person installing the airbag is not sure whether actuation of the secondary-device handle will engage it in the locked position or whether it has already engaged and therefore cannot be correctly inserted. If this happens at an unduly early stage during installation, during subsequent assembly and particularly when the electric power system starts up, the ignition charge may be subjected to voltages which trigger the airbag system. This may result in dangerous injury to the fitters, or the circuit may not be closed in which case the airbag will not operate.

[0005] In addition, even when relatively strong forces act on the handle of the secondary latching, engagement in the locked position should be possible only if expressly desired. The purpose is e.g. to avoid faulty operation during transport and handling.

[0006] The present invention further relates to a connector with a lateral cable outlet of the kind described in the preamble of claim 17. Connectors of the aforementioned kind, with a lateral cable outlet and a casing which is flat in the direction of insertion, are used whenever it is necessary, for reasons of space, to bend the connecting cable by about 90° from the axis of the connector, immediately behind the plug attachment. A situation of this kind occurs e.g. with ignition plugs for airbag-retaining systems, where the airbag and the ignition mechanism are disposed on the impact cup of the steering wheel, where the overall height is restricted.

[0007] In the case of connectors with a lateral cable outlet and a flat casing, there is always a risk that their cable will be pulled out of the mating connector. Although this method of disengaging the connector is not according to specifications, precautions must be taken to reduce the damage in this case to a minimum. This means that the plug casing must not be torn apart and possibly irreversibly deformed by the resulting lever forces. It is also necessary to prevent the cable ends from being partly or completely disconnected from the backs of the plug.

[0008] The object of the invention therefore is to propose a connector with secondary latching and having a state on assembly which is clearly defined at all times and has maximum reliability for avoiding unintentional premature latching.

[0009] The further object of the invention is to improve a connector according to the invention with a lateral cable outlet so that when an axial or oblique pull is exerted on the cable end, it is effectively protected from disconnection and damage to the casing.

[0010] These problems are solved according to the claims. Advantageous embodiments of the invention are specified in the sub-claims.

[0011] In order to show the fitter the exact position in which the connector according to the invention is, there are two engaged positions—a first position in which the secondary latching is not yet operative, so that the plug can still be pulled out, and a second position in which the connector is latched and a special tool may be needed to release the handle.

[0012] According to another feature of the invention, a locking slide is provided in the lid of the casing of the connector, so as to prevent the secondary latching being pressed down out of the assembly position into the latched position unless the locking slide is deliberately pushed sideways. This reliably prevents accidental final latching during assembly.

[0013] Alternatively the handle is disposed so as to be movable transversely to the direction of insertion, so that in the assembly position the handle cannot be pressed into the latched position, this being possible only after being deliberately moved sideways into a position in which the handle can be pressed into the latched position.

[0014] These features ensure that faulty operation during assembly is substantially prevented, and during assembly the fitter will always know the exact state of the connector when installed, so that it cannot be latched prematurely.

[0015] The invention will now be explained in detail by a description of preferred embodiments with reference to the drawings in which:

[0016] FIG. 1 shows an embodiment of a connector according to the invention in section and in the assembly and in the latched position;

[0017] FIG. 2 shows a variant of the embodiment in FIG. 1, in the assembly position;

[0018] FIG. 3 is a view in cross-section of a connector according to the invention with a locking slide for preventing premature latching;

[0019] FIG. 4 shows the latching-preventing means in FIG. 3 in plan view;

[0020] FIG. 5 shows an alternative latching-preventing means in perspective view;

[0021] FIG. 6a-cshows the latching-preventing means in FIG. 5 in three latch positions;

[0022] FIG. 7 is a perspective view of the connector according to the invention and

[0023] FIG. 8 is an exploded view of the connector in FIG. 7.

[0024] FIG. 1 is a longitudinal section through a connector 1 comprising a plug part 10 and a socket part 7. The socket part 7, in the case of an airbag-retaining system, is a part of the casing of the ignition mechanism. On each side of the plug axis 6, the plug part 10 has tongues 4a,4bwhich engage in corresponding slots 3a,3bin the socket part 7, where latches 5a,5bengage in undercuts the shoulders 8aand 8bof in the slots 3a,3b.In the case shown here, the latches have sloping flanks on each side, so that after engagement, the plug part 10 can be pulled out by pulling it strongly. The slots 3a,3bhave a width such that after the latches 5a,5bhave engaged behind the tongues 4a,4ban additional slot 9a,9bfor receiving the locking arms 2a,2bof the handle 2 is formed in the direction of the plug axis 6.

[0025] FIG. 1 shows the handle 2 in the assembly position A on the right half and in the latched position B on the left half. In the assembly position, the locking arms 2a,2bare not received in the slots 9a,9b.On each side the lateral wings 11a,11bsurround the plug part 10 and the latch hooks 12a,12bengage in corresponding grooves formed in the side walls of the plug part 10, so as to lock the handle 2 in this assembly position. In this position, therefore, the plug part 10 can be fitted on the socket part 7, and can also be released from this position by strong pulling, since the latches 5a,5bcan pivot out of the corresponding undercuts. This situation is shown in FIG. 2, which clearly shows that the tongues 4a,4bpivot in the free slots 9a,9b.

[0026] In order finally to latch the connector 1, the handle 2 is pressed in the direction for insertion, so that the sloping end faces of the latch hooks are pressed out of the slots 13a,13b,slide along the side walls of the plug part 10, and finally are latched to the lower edge of the side walls of the plug part 10. In this position the locking arms 2a,2bhave entered the slots 9a,9band prevent the latches 5a,5bfrom swinging back, thus ensuring that the connector has actually been latched. The handle 2 can be latched to the lower edges of the side walls of the plug part 10 in such a manner that a special tool is necessary for releasing it.

[0027] FIG. 3 shows the plug part 10 in longitudinal section. The cable outlet is shown on the right side and a chamber e.g. for a choke is provided on the left side. The handle 2 is on the plug axis 6 and is shown in FIG. 3 in the assembly position, i.e. the locking arms 2a,2bare not completely inserted into the slots 9a,9b.The locking slide 30 prevents the handle 2 from being pressed into the latched position. The slide is mounted in a groove 31 in the casing lid 32 so as to be movable transversely to the direction 6 of engagement and can be moved between a locking position and a position in which it enables the handle 2 to be inserted. In the locking position, the locking slide 30 is engaged by suitable latches 29 on the lid and on the slide. On its surface, the locking slide 30 has grooves 34 which facilitate sliding thereof and enable the locking slide to terminate flush with the lid surface, so that the resulting connector has a very flat construction, particularly since the transverse strut 20 of the handle 2 is also lowered into the groove 31 in the latching position.

[0028] A pin 33 is disposed on the underside of the transverse strut 20 and in the assembly position adjoins the locking slide. Its length is chosen so that in this position the tips of the locking arms 2a,2bjust extend into the slots 9a,9b.

[0029] FIG. 4 is a plan view of the locking slide 30 on the casing lid. The drawing shows an alternative means of securing the locking slide 30, two recesses 39 being provided at the side in the groove 31, for a latch 36 disposed in the side wall of the locking slide 30. In the final latched position, the handle 2 along with the locking slide 30 can be pressed down so far that its surface is flush with the casing lid surface.

[0030] FIG. 5 shows an alternative embodiment preventing accidental latching of the handle in the final position. In this embodiment the complete handle 2 is moved sideways in a groove 13btransversely to the direction of insertion 6, into a position in which the locking arms 2a,2bcan enter the slots 9a,9b.FIG. 5 shows the lateral groove 13b,in which the wings 11a,11bof the handle 2 are guided. Ribs 23 bound the lateral travel distance and prevent any accidental pressure on the handle 2 from spreading out the wings 11a,11bin a position in which the locking arms 2a,2bcannot enter the slots 9a,9b.In addition the connector is constructed so that in the initial latch position the locking arms 2a,2badditionally or alternatively extend upwards from the base of the casing and accidental actuation is impossible. The casing and the inside of the wings 11a,11bare formed with knobs and recesses 25, 26, so that it is possible to detect when the handle is latched in the intermediate position. Latching of this kind is optional and can be omitted if required.

[0031] FIGS. 6ato 6cshow a perspective view of the connector according to FIG. 5 in the initial latching position (FIG. 6a) in which the handle 2 cannot be pressed down. In order to reach the final position, the handle 2 must first be moved sideways into the position shown in FIG. 6b,so that it can then be pressed down into the end position (FIG. 6c). As can be seen, in this version also the handle

[0032] FIG. 7 shows a plug part (1) as a whole comprising an attachment 10 inserted into a complementary plug (not shown) and also comprising a flat casing. The lateral cable outlet is shown on the right side. A cable 46, indicated by chain lines, comes out of the cable outlet 40. The upper part of the connector is covered by a lid 44. A locking handle 45 extends through the lid down to latching arms which extend parallel to the plug attachment, in order to secure the connector after installation.

[0033] The cable outlet 40 has a two-part clamping device 50a,50bwhich will be explained in detail hereinafter. A part of the clamping device 50acomprises a hollow semicylindrical groove formed with retaining ribs 47. A cable 46 is inserted in the groove and, when the casing components are fitted together in the specified manner, the retaining ribs are partly pressed into the cable sheath transversely to the cable axis. The upper part 50aof the clamping device is in the form of a side attachment 48 moulded in one piece on the lid 44 and has an upper wall 60, the underside of which is formed with the upper groove 50ain its centre. The attachment 48 also has two vertical side walls 51aand 51b.Latches are formed on the insides of the side walls 51aand 51band cooperate with corresponding complementary detents 53. The detents 53 are on the second part of the clamping device 50b,which is likewise in the form of an attachment or clamp 49 integral with the casing. The clamp 49 likewise has a central semicylindrical groove with retaining ribs 47 forming the counterpart to the groove 50a,the cable 46 being clamped between them. On the two sides of the groove 50bthe clamp has two arms 56, substantially following the contour of the inner side walls, and their lower outer ends are flush with the lower edges of the vertical side walls 51a,51bof attachment 48. The detents 53 and the corresponding latches 52 are disposed closely above the lower end of the side walls 51a,51bor the arms 56. Preferably, the arms 56 are prestressed slightly outwards when cast, so that when the attachment 48 is locked to the clamp 49, the detents 53 are pressed into the latches 52.

[0034] If a force is exerted on the lid 54 by an obliquely upward or backward pull in opposition to the direction of insertion, tending to loosen the lid from the casing, application of a force in this direction will press the detent 53 more deeply into the corresponding latch 52 and, if the side walls 51a,51byield outwardly, the arms 56 will follow the yielding movement, with the result that the detents 53 cannot be removed from the latches; on the contrary, the two parts of the clamping device are joined together even more firmly. The greater the pull from the direction of the lid and the further the side walls or arms of the clamp move apart, the more firmly the locking device spreads into the undercut of the lid.

[0035] This ensures that the parts of the casing cannot come loose and the cable cannot be pulled out in the axial direction, since the parts of the clamping device 50a,50balways remain firmly pressed together.

[0036] The preceding description of embodiments of the invention should not be regarded as limitative but only by way of illustration.