Electrical connector with improved latch mechanism

Abstract: A circuit board latching device (40, 41) for use with an insulative connector housing (31) includes a retaining wall (82) and a circuit board support post (52) in which the board support post (52) is positioned opposite the retaining wall (82). The latching device (40, 41) of the present invention comprises a main body portion (56) and a mounting mechanism for mounting the main body portion to the housing (31) between the retaining wall (82) and the board support post (52). Furthermore, a latch lug (71) extends from the main body portion (56) which includes a cam surface (72) which is inclined relative to the latch lug (71), and a lock surface (73) which is substantially perpendicular to the main body portion (56). Moreover, the latching device (40, 41) includes a resilient stress reducing arm (79) projecting angularly away from the main body portion (56) toward the retaining wall (82). In one aspect, the mounting mechanism comprises a mounting platform (94) which includes a plate (106) extending from the main body portion (56). A first finger (95) extends substantially downward from one end of the plate (106) while a second finger (96) extends substantially downward from the opposite end of the plate (106) which mountingly engage the housing (31). In another aspect of the present invention, the mounting mechanism comprises an upstanding sleeve (59) mounting member extending from the main body portion (56).

Description: The present invention relates to electrical connector assemblies as known from US-A-5 004 429 and defined in the preamble of claim 1. Generally, main circuit boards or motherboards employed in computers or other electrical equipment are interconnected to an array of secondary circuit boards. There are numerous types of secondary boards such as edge cards, single in-line packages (SIP), memory modules, single in-line memory modules (SIMM) or circuit modules. Circuit boards ordinarily comprise a rigid substrate board having a plurality of integrated circuits mounted thereon. Often, interconnection between a main circuit board and a secondary board is provided through an electrical connector mounted to the main circuit board. These connectors ordinarily include an insulative housing defining an elongated slot which houses a plurality of electrically conductive terminals. The secondary board is inserted into the slot so as to electrically contact the respective terminals. The board is then rotated to its operating position wherein the secondary board generally engages at least two latches disposed on opposing sides of the housing slot. These latches typically provide a contact portion which releasably secures the secondary board in the operational position. In the past, metal latches have been removably installed at opposing ends of the elongated edge receiving slot in order to secure the secondary board in place. These earlier metal latches serve as spring members in which bending forces typically are concentrated in a limited region of the latch. Unfortunately, virtually the entire bending forces are absorbed by the latch in that limited region. Thus, there has been a need for a metal latch for use in an electrical connector which can distribute bending forces experienced by the latch. The present invention meets this need. In one aspect, the present invention includes a circuit board latching device for use with an insulative connector housing which includes a retaining wall and a circuit board support post in which the board support post is positioned opposite the retaining wall. The latching device of the present invention comprises a main body portion and a mounting mechanism for mounting the main body portion to the housing between the retaining wall and the board support. There is provided a latch lug extending from the main body portion which includes a cam surface which is inclined relative to the latch lug, and a lock surface which is substantially perpendicular to the main body portion. Moreover, the latching device may include a resilient stress reducing arm projecting angularly away from the main body portion toward the retaining wall. In another aspect of the present invention, the mounting mechanism comprises an upstanding sleeve mounting member extending from the main body portion. In still another aspect of the present invention, the mounting mechanism comprises a mounting platform which includes a plate extending from the main body portion. First and second fingers extend downward from the plate to engage the housing. In the following, embodiments of the electrical connector assembly will be further described, with reference to the accompanying drawings. FIGURE 1 is a fragmentary, top perspective view of an electrical connector assembly embodiment of the present invention illustrating the staple mounting mechanism for attachment to the connector housing. FIGURE 2 is a fragmentary, side elevation view of the electrical connector assembly of FIGURE 1. FIGURE 3 is a vertical sectional view, taken substantially along the line 12-12 of FIGURE 1, illustrating the staple mounting mechanism of the electrical connector assembly of FIGURE 1. FIGURE 4 is a fragmentary, side elevation view of the electrical connector assembly of FIGURE 1 including a stress reducing arm. FIGURE 5 is a vertical sectional view, taken substantially along the line 15-15 of FIGURE 4, illustrating the staple mounting mechanism of the electrical connector assembly of FIGURE 4. FIGURE 6 is a fragmentary, side elevation view of another embodiment of the present invention employing the staple mounting mechanism. FIGURE 7 is a vertical sectional view of the staple mounting mechanism of the electrical connector assembly of FIGURE 6 illustrating the latch mounted to the housing. FIGURE 8 is a top perspective view of an alternative latch embodiment illustrating the barbs of the mounting mechanism. FIGURE 9 is a fragmentary, side elevation view of the electrical connector assembly of FIGURE 8. FIGURE 10 is a vertical sectional view of the electrical connector assembly of FIGURE 9. Reference will now be made in detail to the preferred embodiments of the invention. While the present invention has been described with reference to a few specific embodiments, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications to the present invention can be made to the preferred embodiments by those skilled in the art without departing from the scope of the invention as defined by the appended claims. It will be noted here that for a better understanding, like components are designated by like reference numerals throughout the various figures. Attention is directed to FIGURE 1, where a fragmentary, top perspective view of an electrical connector assembly embodiment of the present invention illustrating the staple mounting mechanism for attachment to the connector housing is shown. The electrical connector comprises an elongated insulative housing 31-5 with a top side 34-5. In this top side 34-5, a board-edge slot 35-5 is formed. A plurality of electrically conductive terminals (not shown), may be positioned inside slot 35-5 to engage respective conductive pads (not shown) disposed on the board-edge device. Situated at both housing ends of the housing 31-5 and of the elongated slot 35-5, are a pair of removable latches 41-5 which are dimensioned to engage a side edge (not shown) of the secondary circuit board such that the board is releasably secured in its operating position in the slot 35-5 of the electrical connector 30-5. The mechanism of attachment to the insulative housing 31-5 shall be described hereinafter. A main body bottom portion 58b-5 of the latch 41-5 is coupled to a mounting platform 94b-5. As may be seen in FIGURES 1-3, the mounting platform 94b-5 is comprised of a substantially rectangular upper support plate 106b-4 which extends perpendicularly rearward from the main body bottom portion 58b-5 in the direction substantially parallel to the housing top side 34-5 in which it will supportably mate. Respective first and second mounting fingers 96b-5 and 97b-5 extend perpendicularly downward from the opposing side ends of the rectangular support plate 106b-5 in a direction substantially parallel to the respective first and second opposing base side walls 50b-5 and 51b-5 of the base portion 43b-5. It will be appreciated that the first and second downwardly bent mounting fingers 96b-5 and 97b-5 are laterally spaced apart by a distance substantially equal to the cross-sectional width of the housing connector top side 34-5. The properly spaced apart first and second mounting fingers 96b-5 and 97b-5 assure that the mounting platform 94b-5 is snugly supported by the base portion 43b-5 of the respective second support post 39-5, as illustrated in FIGURE 3. The base portion 43b-5 of the respective support post 39-5 defines respective first and second alignment finger grooves 122b-5 and 124b-5 disposed on the respective first and second opposing base side walls 50b-5 and 51b-5. These respective alignment finger grooves 122b-5 and 124b-5 are dimensioned to flushingly receive the respective first and second mounting fingers 96b-5 and 97b-5 such that the respective fingers are seated an aligned. Thus, this helps align the respective latch 41-5 upon mounting to the housing 31-5 (discussed henceforth) and, further, provide lateral support when the secondary circuit board is mounted. Further, the first and second mounting finger slots 98b-5 and 99b-5 are also disposed on the respective first and second opposing base side walls 50b-5 and 51b-5. These respective finger slots 98b-5 and 99b-5 are dimensioned to accept the respective first and second mounting fingers 96b-5 and 97b-5, as shown in FIGURES 2 and 3. Reminiscent of a staple, hence its name, the respective distal ends of the mounting fingers 96b-5 and 97b-5 are bent inward towards the respective first and second mounting finger slots 98b-5 and 99b-5, shown in the phantom lines in FIGURE 3. This staple mounting mechanism simplifies installation and enhances lateral support to the latch 41-5 when the respective distal ends of the mounting fingers 96b-5 and 97b-5 engage the respective finger slots 98b-5 and 99b-5. Accordingly, the respective latch 41-5 is securely mounted to the second housing end. The respective upstanding backstop portion 45-5 provides a rear latch backstop wall 77b-5. FIGURES 4 and 5 represent a preferred previous staple mounting mechanism embodiment which includes a stress reducing arm 79b-6. The stress reducing arm 79b-6, when engaged with the retaining wall of the upstanding retaining portion 45-6, decreases the stress concentration at the spring juncture 74b-6. This embodiment includes a latch front stop 55b-6 protruding toward the respective latch 41-6 from the rear circuit board support 52b-6 to prevent over-extension. Referring to FIGURES 6 and 7 an alternative main body portion 56b-7 is illustrated coupled to the mounting platform 94b-7. Unlike the previous embodiments, the main body portion 56b-7 of this embodiment is substantially curved, rather than planar. Thus, although the vertical height between the latch lug 71b-7 and the housing top side 34-7 remains substantially similar, the actual length of the main body portion 56b-7 is longer than the previous embodiments because of its curved positioning. This increased length enhances the overall flexibility of the main body portion 56b-7 which reduces stress concentration at spring juncture 74b-7. As will be described in greater detail below, this curvature and increased flexibility distributes the bending stress throughout the main body portion 56b-7 when the same is deflected rearward during installation or removal of the secondary circuit board. As illustrated in FIGURE 6, the mounting platform 94b-7 is mounted forward of the main body bottom side 58b-7, as opposed to being mounted rearward. Moreover, the bottom portion 58b-7 of the main body portion 56b-7 extends from the rectangular mounting support plate 106b-7 in a direction substantially parallel to the plate. In the previous latch embodiments, the main body portion extends substantially perpendicular therefrom. Thus, as the main body portion 56b-7 is displaced reward, the stress acting on the main body portion 56b-7 is absorbed all along the curvature. Accordingly, the bending stress is not narrowly concentrated at the spring juncture 74b-7 because it is distributed throughout the curvature of the main body portion 56b-7. This produces a result similar to the stress reducing arms, i.e., reducing stress at the spring juncture 74b-7, but in a different manner. Therefore, while according many of the benefits of a stress reducing arm, the curved main body portion 56b-7 of this latch embodiment 41-7 structurally simpler than embodiments employing the stress reducing arms. The upper portion 57b-7 of the main body portion 56b-7, however, remains substantially planar to promote planar engagement with the front latch stop 55b-7. Further, the backstop portion 45-7 which prevents latch over extension is simplified and substantially planar. Another alternative mounting mechanism mounting the removable latches 41-8 and 41-1 to the housing 31-8 is illustrated in the connector assembly 30-8 of FIGURES 8-10. Similar to the staple mounting mechanism of the previous embodiment, this mounting mechanism comprises a mounting platform 94b-8 which includes a rectangular support plate 106b-8 extending perpendicularly rearward from the main body bottom portion 58b-8. Again, respective first and second mounting fingers 96b-8 and 97b-8 extend perpendicularly downward from the opposing side ends of the rectangular support plate 106b-8. However, in this mounting embodiment, the respective distal ends of the first and second mounting fingers 96b-8 and 97b-8 are not bent inward, respectively, toward one another. Rather, retainment is provided by first and second inwardly inclined barbs 107b-8 and 108b-8 which are defined by the respective first and second mounting fingers 96b-8 and 97b-8. These respective barbs 107b-8 and 108b-8 represent an uncomplicated mechanism for mounting the respective latch 41-8, 41-1 to the respective second housing end 33b-8. As best illustrated in FIGURE 10, the respective base portion 43b-8 defines a respective first and second barb step lO9b-8 and 110b-8 positioned oppositely on the respective first and second opposing base side walls 50b-8 and 51b-8. The first and second barb steps 109b-8 and 110b-8 are appropriately aligned and dimensioned to engage the corresponding first and second mounting finger barbs 107b-8 and 108b-8. Thus, after engagement with the respective steps lO9b-8 and llOb-8, the respective latch 41-8 will be securely mounted to the respective housing end 33b-8.

Claims: An electrical connector assembly comprising an insulative housing (31-5) and at least one metal latch (41-5), said housing (31-5) including a retaining wall (82b-5), a circuit board support post (52b-5) positioned opposite the retaining wall (82b-5), a top side (34-5) defining an elongated slot (35-5), a first side wall (50b-5), and a second side wall (51b-5) disposed opposite the first side wall (50b-5), characterized in that said first side wall (50b-5) defines a first side cavity (98b-5); said second side wall (51b-5) defines a second side cavity (99b-5); and said latch (41-5) comprises: a generally planar mounting plate (94b-5) formed for substantial abutting support against the housing top side (34-5), and including a front side facing the elongated slot (35-5), an oppositely disposed rear side, and a first side as well as an opposed second side; a flexible main body portion (56b-5) including a substantially vertical top portion and a bottom portion (58b-5) resiliently secured to and angled away from the front side of the mounting plate (94b-5); a latch lug (71a-5) extending from the top portion of said main body portion (56b-5), said latch lug (71a-5) including a cam surface (72a-5) inclined relative to said top portion and a lock surface (73a-5) substantially perpendicular to said top portion; a first finger (96b-5) secured to the first side of the plate (94b-5) and extending downward therefrom, said first finger (96b-5) including a first mounting means for engaging the first side cavity (98b-5) of the housing (31-5); and a second finger (97b-5) secured to the second side of the plate (94b-5) and extending downward therefrom, said second finger (97b-5) including a second mounting means for engaging the second side cavity (99b-5) of the housing (31-5). A connector assembly according to claim 1, characterized in that said first mounting means (96b-5) comprises a first deformable end formed to be bent into said first side cavity (98b-5), and said second mounting means (97b-5) comprises a second deformable end formed to be bent into said second side cavity (99b-5). A connector assembly according to claim 1, further characterized by a stress reducing means including a resilient arm (79b-6) projecting angularly away from said main body portion toward the retaining wall (82b-6). A connector assembly according to claim 1, characterized in that said first mounting means (96b-8) comprises a first mounting barb (107b-8) dimensioned to securely engage said first side cavity (109b-8), and said second mounting means (97b-8) comprises a second mounting barb (108b-8) dimensioned to securely engage said second side cavity (110b-8). A connector assembly according to one of the preceding claims, further characterized by a latch lever (75b-5) projecting angularly outward from the top portion of said main body portion (56b-5) to form a cantilever projecting therefrom. A connector assembly according to one of the preceding claims, further characterized by a guidance latch plate (78b-5) extending from the top portion of said main body (56b-5) toward the elongated slot (35-5). A metal latch for an electrical connector assembly according to one of claims 1-6, characterized in that it comprises: a generally planar mounting plate (94b-5) including a front side, an oppositely disposed rear side, and a first side as well as an opposed second side; a flexible main body portion (56b-5) including a substantially vertical top portion and a bottom portion (58b-5) resiliently secured to and angled away from said front side of the plate; a latch lug (71a-5) extending from the top portion of said main body portion (56b-5), said latch lug (71a-5) including a cam surface (72a-5) inclined relative to said top portion and a lock surface (73a-5) substantially perpendicular to said top portion. a first finger (96b-5) secured to said first side of the plate (94b-5) and extending downward therefrom; and a second finger (97b-5) secured to said second side of the plate (94b-5) and extending downward therefrom. A metal latch according to claim 7, characterized in that said first finger (96b-5) comprises a first deformable end, and said second finger (97b-5) comprises a second deformable end. A metal latch according to claim 7, characterized in that said first finger (96b-8) comprises a first mounting barb (107b-8), and said second finger (97b-8) comprises a second mounting barb (108b-8). A metal latch according to one of the claims 7-9, further characterized by a latch lever (75b-5) projecting angularly outward from the top portion of said main body portion (56b-5) to form a cantilever projecting therefrom. A metal latch according to one of the claims 7-11, further characterized by a guidance latch plate (78b-5) extending from the top portion of said main body (56b-5) toward the elongated slot (35-5).

Inventors: CHEN JEFF, CHIEN TON-YO, LAI CHING-HO, LIU CHAO JEN, LU SIDNEY, CHEN, JEFF, CHIEN, TON-YO, LAI, CHING-HO, LIU, CHAO JEN, LU, SIDNEY
Applicants: FOXCONN INT INC, FOXCONN INTERNATIONAL INC.
Application year: 1992
Main classification: H01R13
IPC codes: H01R13, H01R12