GB2319673A - Connector for airbag - Google Patents

Abstract

An airbag squib connector assembly comprises a squib connector (10) and a short circuit spring assembly (12) mounted in a squib housing (4). The short circuit spring assembly (12) comprises an insulative housing having an integrally mounted beam (102) optionally with a latching protrusion (106) that engages in a corresponding recess (110) of a mating section of the connector (10). The protrusion (106) and beam (102) serve to take up residual play after latching of the connector to the squib housing to prevent chattering. Latches (60) retain the connector assembly when mated. Fingers (68, figures 1,4, not shown) of a locking assembly prevent latches (60) from being released after mating. The body of the connector may contain a filter (20, figure 1, not shown).

Description

SQUIB CONNECTOR This invention relates to an electrical connector for connection to a squib or gas generator, in particular for automotive seat belt pre-tensioner or air bag systems.

In automotive applications such as air bag and seat belt pre-tensioners, explosive devices are provided, the explosive device commonly called squibs. Squibs are typically provided with a pair of contacts projecting within a cavity for receiving and mating with a complementary connector, commonly called squib connector. A squib connector assembly comprises a short circuit element that bridges the pin contacts of the squib when the squib connector is unplugged. During plugging, the shorting contacts are biased by the squib connector to break the short circuit. It is known to provide a short circuit contact within a housing of the squib connector assembly, the housing fastened within the squib housing.

Conventional squib connectors also provide resilient latches that engage shoulders of the squib housing for latching the connector thereto. The resilient latches are typically shaped as cantilever beams attached to the connector housing at one end and extending to a free end. In certain designs, the free end is directed towards the mating face of the connector, and in other designs the free end is directed away from the mating face. The former design is less secure than the latter design, because a pulling force on the mated connector creates a moment about the locking shoulder of the latching arm that tends to bias the latching arms inwardly thereby releasing the connector. Such designs thus are often provided with secondary locking members that engage behind the latching arms to prevent inward biasing thereof once mated. Where the latches are attached to the connector housing proximate the mating face and the free ends directed away from the mating face, an unplugging force tends to bias the latch arms outwardly thus increasing the latching strength. The need for a secondary locking system in this design is thus less important. In this design however the latching shoulder should not be provided with a taper if there is no secondary locking member, which leads to slightly greater play between the connector and squib housing once mated. Play in mated connectors can lead to fretting corrosion of contacts due to vibratory movements. It would be desirable to eliminate play yet provide a simple squib connector with robust latching.

It is an object of this veng or. to provide a simple, robust and reliable squib connector assembly.

Objects of this invention have been achieved by providing a squib connector assembly according to claim 1. In particular, a squib connector assembly is provided comprising a squib connector and a short circuit assembly, the squib connector adapted to mate with a squib having contacts within a cavity of the housing of the squib, the connector having a housing comprising one or more resilient latches for securing the connector to the squib, the short circuit assembly comprising a housing securely mountable within the squib cavity, the short circuit assembly comprising a cavity for pluggably receiving the connector mating section therein, wherein the short circuit assembly and connector mating section comprise interengaging play absorption members adapted to eliminate play therebetween in a mating direction once the connector is plugged to the squib.

Advantageously therefore, a squib connector assembly where latching arms are attached proximate the mating face can be provided for robust simple latching, yet play is absorbed for reliable connection.

An embodiment of this invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-sectional view of a squib connector assembly about to be mated to a squib (the connector is shown without contacts); Figure 2 is a view similar to Figure 1 in the fully mated condition; Figure 3 is a cross-sectional view through lines 3-3 of Figure 1; Figure 4 is a cross-sectional view through lines 4-4 of Figure 2; Figure 5 is an isometric view from the underside of the squib connector assembly according to Figure 1; Figure 6 is an exploded isometric view of the connector of Figure 5; Figure 7 is an isometric view of a short circuit spring assembly forming part of the squib connector assembly of Figure 1 and mountable in a housing of the squib; Figure 8 is a top plan view of the assembly of Figure 7; Figure 9 is a cross-sectional view through lines 9-9 of Figure 8; Figure 10 is a view in the direction of arrow 10 of Figure 8; and Figure 11 is a view in the direction of arrow 11 of Figure 8.

Referring to the Figures, particularly Figures 1-4, a squib connector assembly 2 for plugging to a squib 1 (only partially shown) having a housing 4 with a cavity 6 within which a pair of pin contacts 8 protrude, comprises a squib connector 10 and a short circuit assembly 12. The short circuit assembly 12 is securely mounted to the squib housing 4 within the cavity 6.

Referring particularly to Figures 3-6, the connector 10 comprises an insulative housing 14, a pair of receptacle terminals 16 mountable in terminal receiving cavities 18 of the housing 14, a filter 20 mounted in a recess 22 of the housing proximate a wire receiving end 24, and a cover 26 mountable over a top face 28 of the housing for enclosing the contact and filter 20 therein. A stamped and formed collar 28 is received over a wire receiving end of the housing and cover or securely locking the cover against the housing. A pair of conducting wires 30 are received through wire receiving cavities 32 of the housing for connection to insulation displacement contact (IDC) portions 34 of the contacts 16. The cover 26 is provided with protrusions 36 for insert on into the wire receiving channels I s 32, the protrusions 36 digging into the wires 30 for tightly securing the wires in the channels 32 which are provided with strain relief ribs 37. The collar 28 ensures that the cover is securely held against the housing for effective strain relief purposes.

The filter 20 is simply a ferrite block with cavities 38 extending therethrough, through which the wires 30 pass. The ferrite block acts as an inductance for suppressing high frequency signals in the conductors 30.

The cover 36 is further provided with resilient latches 40 engaging in corresponding latch recesses 42 of the housing for clipping the cover thereto.

As best seen in Figures 3-5, a mating section 44 of the connector 10 protrudes below a bottom face 46 of the housing 14. The mating section 44 extends to a mating face 48, the mating section being received within the squib cavity 6. The mating section 44 is generally a rectangular profiled prism with opposed narrow sides 50 and opposed wide sides 52 extending from the mating face 44 to the housing bottom face 46. Resilient latch members 54 are attached to the mating section proximate the mating face 48 along the narrow sides 50 and extend upwardly therefrom to free ends 58 directed away from the mating face 48 and positioned proximate the top face 28 of the housing. Intermediate the attachment and free ends is a locking shoulder 60 provided on a protrusion 61 for engagement wit. a complementary locking shoulder 62 along a side wall 64 o the squib cavity 6. Because the latch arm 54 is attached prsximate the mating face 48, a large extraction force exerted sn the mated connector will tend to bias the free end 58 outwardly, thereby inherently increasing the latching strength (the moment created by a force on the shoulder 60 abcut the attachment end 51 tends to pivot the latching arm outwardly i.e. away from the side wall 50).

In order to ensure complete latching, taking into account manuacturing, assembly and thermal tolerances, a certain gap G,as depicted in Figure 4, between the latch shoulders 60 and the squib shoulder 62 is often unavoidable.

As shown in Figures 4 and 6, the connector can be further provided with secondary locking member 68, for example integrally moulded with the cover 26 via a flexible hinge 70, each secondary lbcking member 68 being inertab1e in a gap or slot 72 between the latch 54 and side wall 50 to ensure that the latch arms cannot be inwardly depressed until the secondary locking member is removed. The latch arms 54 may further be provided with finger grips 74 protruding laterally and positioned proximate the free ends 58, to enable unlatching of the connector.

Referring now to Figures 7-11, the short circuit assembly 12 will now be described. The short circuit assembly 12 comprises an insulative housing 80 bounded by an outer wall 81, and a short circuit spring terminal 82 stamped and formed from'sheet metal and comprising a mounting portion 84 secured within a slot 86 of the housing and a pair of resilient cantilever beam contact arms 88 extending therefrom through a U-bend 89. Each contact arm 88 comprises a contact 90 at a free end, and a camming portion 92 intermediate the free end and U-bend 89. The assembly 12 is mounted within the squib cavity 6 and securely attached thereto by interengaging retention means 94,95 provided on the housing 80 (Figure 11) and squib housing 4 (Figure 1).

In the mated situation, the short circuit contacts 90 are biased aaainst the contact pins 8 of the squib as shown in Figure 1 for short circuit connection between the pair of pin contacts. In the fully mated position, the wide side walls 52 of the connector mating section 44 bias the shunt contacts 90 away from the pins 8 after having engaged the camming portion 92, as shown in Figure 2.

The outer wall 81 of the short circuit assembly housing 80 is proved with opposed windows 94 to enable the connector latch arms 54 to pass therethrough and engage the squib housing side walls 64. The housing 80 further comprises a polarizing protrusion 96 provided at a top face 98 for engaging in a corresponding recess in the squib housing 4 in order to ensure correct orientation of the assembly 12 with respect to the squib.

The short circuit assembly 12 further comprises a resilient play absorption member 100 comprising a resilient beam 102 attached to the housing at ends 103,104 proximate bottom and top faces 99,98 respectively of the housing 80, the beam 102 provided with a protrusion 106 at a substantially central position between attachment ends 103,104 and projecting towards a cavity 108 of the housing 80 receiving the connector mating section 44. The connector mating section 44 is provided with corresponding recesses 110 within which the protrusion 106 resiliently engages by the bias of the spring beam 102. By providing cooperating tapered surfaces 112,114 on the protrusion and recess respectively, a force tending to couple the connector in the short circuit assembly, thereby absorbing any residual play, is thus achieved. The spring beam 102 is separated from an outer wall of the housing 80 by a slot 101, wherein the housing 80 and spring beam can be integrally moulded. By providing the play absorption member on the short circuit assembly, a simple squib housing can be provided. The latter is advantageous because the squib housing is typically made of a machined metal alloy, whereas the short circuit assembly housing can be moulded from plastic. Latching nevertheless occurs directly between the connector and squib housing for greater strengthened security because there is no reliance on intermediate parts.

Claims (10)

1. A squib connector assembly comprising a squib connector adapted to mate with a squib having contacts within a cavity of a housing of the squib, the connector having a housing and a mating section which extends from a bottom surface of the housing and includes one or more resilient latches for securing the connector to the squib, and a short circuit assembly having a housing securely mountable within the squib cavity and a cavity for pluggably receiving the connector mating section therein, the short circuit assembly and connector mating section including interengaging play absorption members adapted to eliminate play therebetween in a mating direction once the connector is plugged to the squib.

2. The connector assembly of claim 1 wherein the or each connector latch is attached at an attachment end to the mating section proximate a mating face thereof.

3. The connector assembly of claim 2 wherein the or each latch is in the form of a cantilever beam extending from the attachment end to a free end proximate a top face of the connector.

4. The connector assembly of any one of the preceding claims wherein the connector mating section has a roughly rectangular profile, when considered in cross-section transverse to the mating direction, said profile being formed by opposed narrow end walls and opposed wider side walls and wherein the latches extend along the end walls.

5. The connector assembly of any one of the preceding claims wherein the interengaging play absorption members comprise a resilient beam having a protrusion engaging in a recess.

6. The connector assembly of claim 5 wherein the resilient beam is provided on the short circuit assembly and the recess in a side wall of the connector mating section.

7. The connector of claim 6 wherein the resilient beam is attached to the short circuit assembly housing at ends proximate opposed top and bottom surfaces thereof.

8. The connector of claim 6 or 7 wherein the resilient beam is integrally moulded with the short circuit assembly housing and wherein a slot is formed between the beam and the housing outer wall.

9. The connector of any one of preceding claims 5 to 7 wherein the protrusion and the recess are both provided with oblique abutment surfaces that interengage.

10. A squib connector assembly constructed and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.