The present invention relates to electrical connectors and more particularly to latching systems for securing matable electrical connectors together.

Various latching systems are known for latching together housings of opposing electrical connectors being mated to engage mating pairs of contact terminals secured therein. When one of the connectors is a right angle connector mounted to a circuit board, the latching system needs to be provided at either the two ends of the connector or along a common side parallel to a circuit board. To minimize real estate on the circuit boards it is more desirable to have a latching system that is on a common side of the housings. U.S. Patent 5,344,335 discloses one such latching system in which one of the connectors includes a latch arm having a spaced apart pair of latches, each being received in latching slots on the other connector near the lateral ends of the connectors. This type of latching system, however, requires additional height beyond the housing envelope of the connector, which may interfere with stacking the connectors close together. In those instances where it is desirable to have an array of connectors in a closely stacked arrangement, such as a card cage, for example, it is desirable to have a latching system that essentially functions within the envelope of the housing walls and one that furthermore provides a clear indication that the housings are in a full mated condition. It is also desirable to provide a latching system that can minimize that possibility of incomplete latching and incomplete mating.

The present invention is directed to a latching system for securely latching first and second connectors together along a mating axis. The first and second connectors include respective first and second housings. A pair of latch arms are spaced a selected distance

entered the corresponding openings beside the associated latch arm.

FIGURE 4 is a view similar to that of Figure 2 illustrating a further mating of the connectors wherein the end of latch arms engage the wider portion of embossments.

FIGURE 5 is a view similar to that of Figure 2 wherein the connectors are almost mated and the latches are deflected around the embossments. FIGURE 6 is a view similar to that of Figure 2 showing the connectors after they have been fully mated and the latch arms engaged around the latching embossments.

For purposes of illustrating the invention, the latching system is being shown in use with a terminal block connector that is matable to a receptacle connector, shown as a pin header, intended to be mounted in a card cage. It is to be understood that the latching system may be used with other connectors as well.

As shown in Figures 1 through 6, the receptacle connector 120 includes a housing 122 having side walls 124 and end walls 130, which together with the base 132 define a plug receiving cavity 134 that is open at the mating face 133. A plurality of terminals 138 are disposed in the cavity 134, each terminal 138 having a first connecting portion 140 disposed for mating with the complimentary terminals 90 of mating connector 20. As seen in Figure 1, receptacle connector 120 is a right angle connector having second connecting portions 142 adapted to be electrically connected to terminal pads of a circuit board 160. Side wall 124, which is opposite board mounting face 135, includes a pair of latch arms 126 spaced a selected distance apart along the common wall and extend to free ends 127 proximate the mating face 133. As shown herein the latch arms 126 are disposed within recesses 125 of the side wall 124 such

of the connectors, which move rapidly together until the latch arms latch behind the end of the corresponding embossment. When the latching sections of the latch arms pass the forward most radii of the embossments the resistance to latching suddenly ceases. The latching sections continue to move along the flat surfaces of the embossments and upon reaching the ends thereof immediately latch behind the embossments to secure the connectors together. The force required to overcome the resistance between the latch arms and the rearwardly facing surface of the embossments when unmating the connectors results in accelerated unmating thus minimizing any damage to terminals if the connectors are unmated when the system is energized. It is an object of the invention to provide a latching system that stabilizes the axial alignment and orientation of the connectors prior to mating of the terminals therein.

It is a further object of the invention to provide a latching system that assures that both mating and unmating of the terminals of the connectors will occur rapidly.

An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:

FIGURE 1 is a perspective view of plug and receptacle connectors prior to mating with the receptacle exploded from the circuit board and the frame of a panel. FIGURES 2 through 6 illustrate the sequence of mating of the connectors and the latching system.

FIGURE 2 is a flat plan view illustrating the initial alignment of the connectors with guide posts at the end of the connectors providing the alignment. FIGURE 3 is a view similar to that of Figure 2 illustrating partial mating wherein the embossments have

momentum generated by the force accelerates the speed at which the connectors are mated. As the force is increased the connectors are brought closer together and latch arms 126 are deflected outwardly by embossments 50 until the latching sections pass the forward most radii of the embossments and the resistance to latching suddenly lessens. The latching sections move along the flat surfaces of the embossments until the latch arms reach the latch surface 54 whereupon the latch arms 126 resile back to there original position with latch surface 128 engaging the latch surface 54 of embossments 50 to hold the two connectors 20, 120 securely together. As seen in Figures 2 through 6, side walls 124 also include raised embossments 129 which act as anti- overstress features to prevent the latch arms 126 from being deflected outwardly past their breaking point. Figure 6 shows the two connectors 20, 122 in the fully mated condition.

The latching system of the present invention offers a number of advantages. The shape of the embossment 50 and the latch arms 126 are dimensioned such that it requires an increase in force to mate or to unmate the connectors. This extra force is sufficient to deflect the arms 126 such that once the deflection has begun the completion of the mating or unmating is carried out rapidly to help ensure that the connectors 20, 120 are fully mated or unmated. The speed at which the mating or unmating occurs minimizes damage to the terminals in the connectors when or if the connectors are mated or unmated while the current is flowing or "hot".

The extended length of beams 52 on the embossments 50 assure that the plug connector 20 is guided into correct and stabilized axial alignment and orientation with receptacle connector 120 prior to the mating of the receptacle terminals with the pin terminals of the header. While the guide posts 131 begin the alignment, the beams 52 ensure that the two connectors 20, 120 are

that they are substantially- contained within the thickness of the side wall 124, thus enabling connector 120 to be disposed in a shell 150 for use in a card cage or the like, as illustrated in Figure 1. Side wall 124 further includes an anti-overstress embossment 129 proximate the leading end of the latch arm 126. Housing 122 also includes a pair of guide posts 131 extending outwardly from the mating face 133 proximate the end walls 130 for establishing initial alignment. Referring now to Figures 1 through 6, plug connector 20 includes a housing 22 having a plug portion 40 slidably received in a shell portion 24. The plug portion 40 includes sidewalls 48. A pair of latching embossments 50 including beams 52 extending along a common side wall 48 and outwardly from the housing 22 a second selected distance beyond the mating face 46 to free ends 53. The embossments 50 are essentially L- shaped with beams 52 being narrower than the rearward block-like section of the embossment 50. The block-like section includes a latch engaging surface 51 proximate the mating face 46 and a rearward facing latch surface 54.

Figure 2 illustrates first and second connectors 120, 20 in alignment for mating with the respective guide posts 131 aligned with corresponding apertures 33 in plug 20 and the leading ends 53 of beams 52 proximate the mating face 133 of receptacle connector 120. In Figures 3 the connectors 120, 20 are moved closer together such that the beams 52 enter the spaces 123 between the forward leading ends 127 of the latch arms 126 and pass freely beside the latch arms 126 until the slanted surface of leading end 127 of the latch arms 126 engage the latch engaging surfaces 51 of embossments 50 as shown in Figure 4. At this stage of mating resistance to movement is increased by the engagement of surfaces 127 and 51 such that increased force is needed to mate the plug 20 with the receptacle 120. The

We Claim:

1. A system for latching first and second connectors (120,20) together along a mating axis, the first and second connectors including respective housings (122,22), a pair of latch arms (126) spaced a selected distance apart along a common side (124) of the first housing (122) and extending to free ends (127) , said latch arms (126) being adapted to cooperate with respective complementary latching surfaces (54) positioned along a corresponding common side surface (24) of the second housing (22) , the system being characterized in that: respective free ends (127) of said latch arms (126) include latching projections; said common side surface (24) of said second housing (22) includes a pair of embossments (50) extending outwardly therefrom, said embossments (50) being positioned in alignment with said free ends (127) of said latch arms (126) to be initially abutted by camming surfaces of said free ends (127) during initial stages of latching; and said latch arms (126) are adapted to be deflected toward ends (130) of said first housing (122) upon said camming surfaces bearing against said embossments (50) , whereafter the latching projections pass by the embossments (50) and become latched therebehind; whereby said latch arms (126) are deflectable in a direction parallel to said common side (124) of the first housing (122) minimizing the clearance area adjacent the housing needed for deflection of the latch arms.

2. The system for latching of claim 1 wherein said latch projections face toward each other and said latch arms (126) deflect away from each other. 3. The system for latching of claim 1 wherein said latch arms (126) are disposed in recesses (125) on said common side surface (124) such that overall dimensions

not mated at an angle. The- surface 51 of embossments 50 are a sufficient distance from the mating face 46 of plug 20 to assure that the terminals 138, 90 do not touch until the plug connector 20 begins to accelerate under the increase in force to overcome the resistance between the latch engaging surface 51 of embossments 50 and the leading ends 127 of latch arms 126. During unmating the resistance of the embossment 50 and latch surface 54 thereof against the latch surface 128 of the latch arm 126 also require sufficient force to deflect the latch arms 126 outwardly thus ensuring that the connectors 20, 120 are unmated quickly again to minimize any damage to the terminals when unmated under "hot" conditions. The latch arm of the present invention operates substantially within the envelope of the side wall of the connector thus permitting connectors 120 to be spaced adjacent one another without having to allow additional spacing for a latch on the side or requiring additional real estate on the circuit board for end latches. Alternatively the connectors 120 may be inserted into respective outer shells 150, such as shown in Figure 1, and used, for example, in a card cage or the like.