GB2311420A - Airbag connector encouraging complete connection - Google Patents

Abstract

A connector assembly for example for automotive airbag applications, comprises a latching mechanism 74,86 that either encourages complete coupling of the connectors or completely separates the connectors if only partial (faulty) coupling is effected. Resilient latching arms 74 are formed from a planar top wall 68 of a first connector and are interconnected by resilient wall portions 70 at the mating end 12 to a base wall 66. The complementary latching block 86 of the complementary connector comprises a substantially prismatic arrow shaped body for prising apart the latch arms 76. Separation of mated connectors is effected by squeezing the resilient side wall portions 70 together, such that the latching arm extensions 76 buckle upwards.

Description

ELECTRICAL SAFETY CONNECTOR This invention relates to a connector with a latching mechanism to ensure complete coupling of mated connectors, or rejection in the event of incomplete coupling. The invention also relatas to a connector for safety functions, such as automotive airbag or seat-belt pretensioner devices.

It is known to provide electrical connectors with latching systems that incorporate a mechanism to avoid partial coupling of electrical connectors. An example of a known latching system encouraging coupling, is described in European patent 0039548. A first connector is provided with latching arms in the shape of cantilever beams having locking shoulders proximate a free end engageable with a locking shoulder formed on a protrusion of the complementary connector. The protrusion of the complementary connector comprises a first inclined surface that acts as a ramp that the locking shoulders of the latch arm ride up, the protrusion having a second inclined surface extending from the first surface and inclined downwardly, such that the latch arm protrusions ride down the second surface until latching engagement of the complementary locking shoulders. The first and second surfaces join together to form an apex which is the highest point of the protrusion over which the latch arm has to pass. If there is incomplete latching, the first inclined surface, in conjunction with the resilience of the latch arm will encourage the connectors to separate.

Once however the latch arm locking shoulders have passed over the apex of the protrusion, the second inclined surface will encourage full coupling of the connectors.

The risk of partial coupling of the connectors is thus reduced.

It is desirable in certain applications to increase the reliability of such latching systems and, furthermore, to provide a more robust and compact latching system. In particular, it is sometimes desirable to increase the effect of rejection or acceptance of the coupling of the connectors. In certain safety applications, such as for automotive airbag ignition devices, short circuiting of adjacent contacts is required. It is already known to provide short circuit contacts in a connector, but this is typically a separate spring member that has the disadvantage of increasing volume and cost of the connector, whilst decreasing reliability of the short circuit function. It is desirable to provide this short circuit safety function in a reliable, yet compact and cost effective manner.

It is an object of this invention to provide a connector with a latching mechanism that reliably ensures complete latching of coupled connectors.

It is an object of this invention to provide a connector with a latching mechanism that is compact, robust and ensures secure coupling of mated connectors but nevertheless enabling easy uncoupling.

It would be advantageous to provide a compact, cost effective and reliable connector with short circuiting of contacts during an uncoupled state, for example for airbag applications.

Objects of this invention have been achieved by providing an assembly according to the claims. In particular, an assembly is provided comprising a first connector matable to a second connector, the first and second connectors each having a housing within which terminals for connection to conducting wires are mounted, wherein the housing of the first connector comprises latching arms extending from an attached end to a free mating end where latch protrusions are provided, the latch protrusions directed towards each other and biasable for insertion of a latch block of the second mating connector therebetween during coupling, the latch block having an arrow shaped leading end separating the latch arms when inserted between the extensions, the oblique angles of the leading end provided such that incomplete coupling of the connectors causes uncoupling.

The rear end of the latching block can also be provided with angled surfaces that encourage full mating of the connectors once the latch block is inserted sufficiently past the extensions of the latching arms.

The latch arms can be arranged in substantial mirror image symmetry about a central axis of the connector, and furthermore the latch arms and extensions can be made to extend in a substantially planar manner.

The latch arms can extend from a top wall of the connector housing and can be attached via C-shaped resilient wall portions to a base wall that extends from a bottom wall of the connector, the mating connector being received between the top and bottom walls. By squeezing the C-shaped spring sections, the latch arm extensions are biased together until abutment with each other, whereby continued pressure on the C-shaped spring section causes buckling of the extensions in a direction away from the base wall such that latch block can be retracted thereunder for uncoupling.

The positioning of the latch arms in a mirror image and substantially planar manner enables a very compact but robust latching system. Furthermore, the higher resiliency provided to the beams of the latch arms and engagement of the latch extensions with the arrow shaped leading end of the complementary latching block ensures that partial coupling will cause the connectors to uncouple fully, thereby providing easy detection of the faulty coupling.

The higher resiliency of the latch in combination with the inclined surfaces of the rear end of the latching block encourages full coupling. Unlatching can only occur upon squeezing together of the C-shaped wall portions and simultaneous pulling apart of the mated connectors. An operator must therefore positively and purposefully hold the connectors with both hands in order to uncouple them.

Unmating of the connectors by catching of the latch on external objects is therefore not possible.

Other objects of the invention have been achieved by providing an electrical connector having electrical contacts mounted in an insulative housing and having a resilient short circuit contact arms that contacts a short circuit arm of an adjacent contact, wherein the short circuit contact arms are integrally formed with their respective contacts. The contacts may be stamped and formed from sheet metal. The short circuit contact arms may be in the shape of cantilever beams attached to the contacts remote from the mating end, and extending to free ends proximate the mating end, whereby the contact portion of the short circuit arms is proximate the mating end of the connector.

Further advantageous aspects of the invention are described in the claims, or will be apparent from the following description and drawings.

An embodiment of this invention will now be described by way of example, with reference to the figures, in which: Figure 1 is an isometric view of a first connector according to this invention; Figure 2 is an isometric view of a second connector matable with the first connector; Figure 3 is an isometric view of a connector assembly comprising the first and second connectors according to this invention, the connectors about to be coupled; Figure 4 is a view similar to that of Figure 3 but with the connectors fully coupled; Figure 5 is an isometric view of the underside of the connectors prior to mating; Figure 6 is a partial isometric view of an IDC connection section of the second connector; Figure 7a is an isometric view of a tab terminal for mounting in the first connector, the tab terminal comprising short circuit spring contact arms; Figure 7b is a plan view of the terminal of Figure 7a; Figure 8 is an isometric view of a receptacle terminal for assembly in the second connector and matable with the tab terminal of Figures7a and b.

Referring first to Figure 3 and Figures7 and 8, an electrical connector assembly 2 comprises a first connector 4 and a second connector 6 matable together.

The first connector 4 is a tab connector comprising an insulative housing 8 with terminal receiving cavities extending from a conductor receiving end 10 towards a mating end 12 that receive tab terminals 14 (Figure 7a).

The tab terminals 14 are stamped and formed from sheet metal and comprise a connection section 16, an intermediate section 18, and a contact section 20. The connection section has a U-shaped base 22 and a pair of insulation displacing contacts 24 traversing the base 22 and having slots 26 for cutting through the insulation layer of conducting wires 28 (Figure 3) for contacting the inner conducting cores thereof. The tab contact section 20 extends from a base wall 28 of the transition section 18, the contact section further comprising resilient cantilever beam short circuit contact arms 30 extending from a top end of the intermediate section 18 to free ends 32 proximate a foremost end 34 of the tab. When a pair of contacts 14 are mounted in adjacent cavities of the connector housing 8, contact protrusions 36 proximate the free ends 32 of the short circuit contact arms, bias against the adjacent short circuit spring arm of the adjacent contacts for electrical connection thereto. When the connector 4 is uncoupled, adjacent contacts are thus short circuited. This is a particularly important function in certain applications such as automotive airbag connectors, where potential differences between conductors must be avoided in order to prevent inadvertent ignition of the airbag or other safety device when they are uncoupled, for example during servicing or maintenance.

Inclusion of the contact spring arms on the tab contact integrally formed therewith ensures a compact and cost effective short circuit mechanism that avoids the need for a separate short circuit spring contact. Furthermore, the design makes effective use of material for a cost effective solution, whereby the short circuit spring arms extend substantially from the side walls of the U-shaped IDC connection sections 22, above the tab contacts.

Provision of the spring contact arms alongside the tab also provide sufficient length for adequate flexibility of the short circuit arms.

Referring to Figure 2, the second connector 6 comprises an insulative housing 40 having terminal receiving cavities 42 extending from a conductor receiving end 44 towards a mating end 46, and receptacle contacts 48 (see figure 8) having an IDC connection section 50 and a receptacle contact section 52 for mating with the pin contact section of the tab terminal 14.

Referring to Figure 5, the second connector 6 is shown with an axially extending rib 98 projecting above a bottom wall 99 of the housing, the rib being inserted between the short circuit spring contact arms 30 of the tab terminals 14 during coupling of the connectors 4,6.

Referring to Figure 6, a connection section 54 of the second connector (also see Figure 2) is shown, comprising a terminal receiving section 56 and a cover 58. The cover 58 comprises latches 60 latchable to the terminal receiving section 56 in a preassembly position as shown in Figure 6, whereby the conducting wires 28 can be inserted above the insulation displacing connection section 50 of the terminals 48. The cover 58 can subsequently be depressed towards the terminal receiving section 56 until the latches 60 engage in a fully locked position, whereby stuffer protrusions 62 positioned above the conducting wires 28 stuff the wires into the IDC slots 26 for electrical connection thereto. Rapid connection of the conductors 28 to the connector 6 is thus ensured.

Conducting wires are connected in a similar manner to the first connector 4.

Referring to Figure l, the first connector 4 is shown comprising a latching section 64 extending from a terminal receiving section 63 to the mating end 12, and comprising a base wall 66, a top wall 68 and side wall portions 70 extending therebetween. The bottom top and side walls form an area 72 for receiving the second connector 6 therein. The top wall 68 comprises a pair of latch arms 74 that are attached to the housing proximate the terminal section 63, and extend to the mating end 12 where latching extensions 76 are provided. The latching extensions 76 are directed towards each other and separated by a small gap 78. The latching extensions 76 provide slightly obliquely inclined latching shoulders 80 directed away from the mating face 12 for engagement with a complementary shoulder 90 (see Figure 2) of the second connector 6. The side wall portions 70 bulge outward in a generally C-shape and interconnect the base wall 66 to the latch arms 74 proximate the mating end 12. Each latch arm 74 is otherwise separate from the base wall 66 by a gap 82 to allow resilient biasing of the latch arm 74 in the direction d which is in the plane of the top wall 68 but transverse to the mating (or axial) direction a. By squeezing together the resilient side wall portions 70 (in the direction d') the free ends 84 of the latching extensions 76 abut together and pivot upwards in the direction p as shown in Figure 1, away from the base wall 66. The latter enables uncoupling of the mated connectors as will be more clear hereinafter.

Referring to Figure 2, the second connector 6 is shown further comprising a latching block 86 which comprises a substantially planar top wall 88 extending parallel to a top wall 41 of the housing 40 and attached thereto by upstanding walls or pillars 90 that are recessed with respect to the outer periphery 92 of the latch top wall 88. The pillars 90 include latching shoulders 94 (see Figure 3) that are angled to cooperate with the latching shoulders 80 of the complementary connector for secure coupling of the connectors. The oblique angle is also such, that a force component is generated in the mating direction a when the complementary shoulders 80,90 are partially engaged, to promote complete coupling of the connectors 4,6.

The wall portions 90 have a height h greater than the thickness t of the latch extensions 76 such that the latch block top wall 88 passes over the extension 76 during coupling. Wall portions at a leading end 96 of the latching block 86 are also provided slightly recessed from the plate portion 88 in a similar manner. The leading wall portions 96 however form a more acute angle with the mating direction a than the rear wall portions 94 in order to form an arrow or wedge shape insertable in the gap 78 between the latch extension 76. The latter enables the latch block 86 to prise the latch arms 74 apart resiliently until full coupling as shown in Figure 4 where the latch arms 74 snap back into their natural position.

The angle of the wedge is adapted to separate the mated connectors in the event of incomplete coupling (i.e. the frictional force is less than the separation force component in the directiona. Axial pulling apart of the coupled connectors causes the latch arm shoulders 80 to abut latch block rear pillars 90, which, in view of the recess, prevents upper biasing or pivoting (in direction p) of the latch arm extension 76, thereby preventing inadvertent uncoupling of the connectors.

The oblique angle (with respect to the axial direction a) of the mating latching shoulders 80,90 is such that the frictional force and spring force does not allow prising apart of the extensions 76. By squeezing together the side walls 70 however, (in the direction d') the latch extensions 76 buckle upwards (as long as no axial separation forces are exerted on the connectors at that moment) whereby pulling apart of the mated connectors then causes the periphery 92 of the latch block top wall 88 to ride under the latching shoulders 80, further prising the latching extensions 76 upwards to allow separation of the connectors 4,6.

The substantially planar latch arms 74 provide for a connector with relatively low height, but nevertheless with a particularly robust latching system. Furthermore, if only partial coupling of the connectors is effected, the resilient biasing of the ends 84 of the latching extensions 76 against the oblique leading end 96 of the latching block, separates the connectors, thereby ensuring that partial coupling does not occur. If however the lateral apices 97, that form the joining point of the rear and leading wall portions 90,96, have passed through the gap 78 beyond the latching shoulders 80 of the latch arms, the connectors are forced in the fully coupled position by engagement of the latching shoulder 80 with the oblique rear latching shoulder 94 of the latching block 86. It is thus ensured that the connector is either fully coupled or fully uncoupled.

Action of the latch arms 74 in the plane of the top wall 8, integrally molded with the resilient side walls 70, provides for a sturdy reliable latching mechanism that is also compact and can not be easily damaged by external objects.

Claims (9)

1. A connector assembly comprising a first connector and a second connector matable therewith, the first connector comprising a housing and a pair of latch arms in an opposed relationship and cooperable with a complementary latch member of the second connector for locking the connectors together in a fully mated condition, each latch arm having, at a mating end, a latching extension extending to a free end, the free ends of the opposed latching extensions facing each other for receiving the complementary latch member therebetween, the complementary latch member comprising a latch block having a leading end with oblique surfaces for prising apart the latching extensions during coupling, and the angle of the oblique surfaces of the leading end being such that the connectors are separated if the coupling is incomplete.

2. The connector assembly of claim 1 wherein the latch block leading end is wedge shaped.

3. The connector assembly of claim 1 or 2 wherein the latch block has oblique rear latching surfaces that engage latching surfaces of the latching extensions, the oblique surfaces encouraging complete coupling when the leading end of the latch block has been inserted past the latching extensions during coupling.

4. The connector assembly of claim 1, 2 or 3 wherein the first connector housing has a top wall, a bottom wall opposed thereto, and side walls, the latching extensions forming part of the top wall.

5. The connector assembly of claim 4 wherein the latching extensions are interconnected to the bottom wall by elastic portions of the side walls, the elastic wall portions being resiliently biasable toward each other thereby pivoting the latching extensions away from the bottom wall.

6. The connector assembly of claim 5 wherein the elastic wall portions bulge outward in opposed directions to each other.

7. The connector assembly of claim 4, 5 or 6 wherein the latch arms are substantially planar and formed in the top wall.

8. The connector assembly of any preceding claim wherein the latch block extends above a top wall of a housing of the second connector.

9. The connector assembly of claim 8 wherein the latch block has a top wall that extends over and beyond the latch block rear latching surfaces such that the latching extensions are received between the housing top wall and at least some of the latching block top wall when the connectors are coupled.

1 0. A connector assembly constructed, arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.