Connector housing with improved latch members

Abstract: A connector housing (4) includes a pair of latch arms (22) along sides thereof, which extend forwardly to latch with corresponding latching means (48,52,54) of a housing of a mating connector (2). Each latch arm (22) is joined integrally to the housing sides (18,20) by a flexible hinge joint (19) which allows the deflection of the latch arm (22) during mating and unmating. The hinge joints (19) include midsections (60) which have enlarged ends (62,64) extending therefrom. Radiused sections are provided on the enlarged ends (62,64). The radiused sections are configured to properly distribute the stresses associated with the latch arms (22), such that as forces are applied to the latch arms (22) concentration of stresses will be avoided on the hinge joints (19).

Description: The invention relates to improved latch members used with an electrical connector housing. In particular, the latch members are configured to eliminate stress concentration points, thereby minimizing the potential for latch breakage. Housings for certain electrical connectors are molded from dielectric plastic material and are intended to be secured to mating connector housings when the connectors have been moved together in a mated condition, in which the respective arrays of electrical contacts are mated to complete electrical connections. In some of these connectors, hardware is fastened to the respective housings to secure them together in their mated condition, but it is desirable that the housings have an integral latching means. Integrally molded latch arms are disposed along opposed sides of the housing of one of the connectors and extend forwardly to latchingly engage corresponding latching surfaces of the housing of the other connector, when the connectors are moved together into a mated condition. Latch arms used for securing connectors together are known from US-A-4,867,700 and assigned to assignee hereof. The latch arms include rearward portions which are deflectable to unlatch the latch arms when it is desired to separate and unmate the connectors, in which case the latch arms can be said to be hingedly joined to the housing. Such latch arms are subjected to stress and torque during mating and unmating of the connectors, and the hinge joint must be rugged and durable to withstand many cycles of mating and unmating, especially taking into consideration that the hinge joint is molded of plastic material which can commonly lose strength over time when worked and subjected to temperature cycling as well. It is desired to provide hinge joints for latch arms of connector housings which are designed to resist stress and torque and yet be flexible to allow many cycles of deflection of the latch arms. The present invention consists in a connector housing as defined in claim 1. A connector housing according to the preamble of claim 1 is disclosed in US-A-4 944 693. There is described herein a connector housing molded of plastic material and matable with a corresponding connector housing. The connector housing has a pair of latch arms on opposite sides thereof having respective latching members at forward free ends thereof. The latch arms cooperate with latching means of the corresponding connector housing to maintain the connector housings in a mated condition. Each latch arm is joined to a respective side of the housing at a hinge joint which is spaced a selected distance rearwardly from the forward free end of the latch arm. The hinge joints have midsections with first and second ribs integrally attached to the midsections. The first ribs are positioned at first ends of the midsections and the second ribs are positioned at second ends of the midsections. The first and second ribs extend beyond sidewalls of the midsections in a direction which is essentially perpendicular to the longitudinal axis of the midsections. The midsections and the first and second ribs extend between and are integrally attached to the latch arms and the connector housing. The configuration of the hinge joints ensures that as forces are applied to the latch arm, the associated stresses of the hinge joint will be distributed to the first and second ribs to prevent the failure of the hinge joint. It is an objective of the invention to provide a hinge joint for each latch arm of a connector housing which is capable of flexure to allow deflection of the latch arm during mating and unmating of the connector with a mating connector. It is a further objective for such a hinge joint to resist stress and torque and be durable over many cycles of latch arm deflection, allowing many cycles of connector mating and unmating. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: FIGURE 1 is a perspective view of a connector housing having a pair of latch arms joined thereto by hinge joints; FIGURE 2 is a top plan view of the connector housing with portions of the latch arms shown in cross-section to illustrate the hinge joints which join the latch arms to the connector housing; FIGURE 3 is a perspective view of the connector housing and a latch arm thereof broken away from the connector housing to expose the hinge joint; FIGURE 4 is a perspective view of the latch arm; FIGURE 5 is a partial perspective view, similar to that of Figure 3, of the latch arm broken away from the housing to expose the hinge joint; FIGURE 6 is a top plan view of the connector housing being mated to a mating connector housing; and FIGURE 7 is a top plan view, similar to Figure 6, of the connector housing and the mating connector housing in the mated condition. Referring to Figures 1, 6 and 7, a preferred form of a connector assembly in accordance with an embodiment of the invention comprises a plug connector 4 and a receptacle connector 2. The plug connector 4 comprises a block 6 of insulating material, such as nylon, having a mating face 8 and a rearward face 10. A plurality of contact receiving cavities 12 extend axially through the block from the rearward face to the mating face and are adapted to receive contact terminals which are crimped onto wires. The plug connector 4 contains contact sockets which are adapted to receive the projection ends of contact pins contained in the receptacle connector 2 of the connector assembly. Block 6 has upper and lower surfaces 15, 17 and side surfaces 18, 20 on which latch arms 22 are provided. The latch arms 22 are generally flat platelike members integrally joined to the sides of the housing at respective flexible integral hinge joints 19 located approximately midway along the latch arms. Each latch arm 22 includes a forward portion 34 concluding in a free end 36 having a latching member 38. The forward portions 34 have grooves 23 which extend from proximate the hinge joints 19 to the latching members 38. Rearwardly facing shoulders 25 are provided at the interfaces between the latching members 38 and the grooves 23. These shoulders 25 are adapted to cooperate with barbed ends 52 of latch arms 48 which are mounted on the corresponding sides of the receptacle 2, as best shown in Figures 6 and 7. Latch arms 22 further include rearward portions 42 which extend rearwardly from the hinge joints 19. The rearward portions 42 are configured to allow the user to grip the portions and release the plug connector 4 from the receptacle connector 2, as will be more fully described. During the mating of the connectors, latch arms 22 are deflected outwardly as latching members 38 ride over barbed ends 52 of latch arms 48, as shown in Figure 6. Upon mating, latching members 38 are moved beyond the barbed ends 52, such that the barbed ends 52 are positioned in the grooves 23. In this position shoulders 25 of latch arms 22 cooperate with shoulders 54 of latch arms 48 to prevent inadvertent delatching caused by stress or vibration when the connectors are in their mated condition. The connector-proximate portions of latch arm free ends 36 preferably include an angled surface 44 to engage angled surfaces 56 of barbed ends 52 and bear thereagainst to initiate deflection of the latch arms 22 outwardly. During unmating, rearward latch arm portions 42 are adapted to be urged toward each other, rotating latch arms 22 about their respective hinge joints to delatch latching members 38 from barb ends 52, whereupon the plug connector 4 can be move rearwardly away from the receptacle connector 2. Each latch arm 22 has a pair of hinge joints 19, as best shown in Figures 4 and 5. Each hinge joint is capable of flexure during the deflection of the latch arm. For ease of explanation and understanding, the detailed description for one hinge joint will be provided. However, all hinge joints are identical and the detailed explanation provided applies to each of the hinge joints. Referring to Figures 4 and 5, hinge joint 19 has a narrow midsection 60 with enlarged ends or ribs 62, 64 integrally attached thereto at respective ends thereof. The ribs 62, 64 extend from the midsection 60 to respective end surfaces 66, 68. In cross-section the ribs 62, 64 extend beyond the sidewalls of the midsection 60 to give the hinge joint a "dogbone" configuration, as best shown in Figure 5. In this configuration the longitudinal axis of each rib extends in a direction which is essentially perpendicular to the longitudinal axis of the midsection. As is illustrated in the figures, the hinge joint has first radiused sections A and second radiused sections B. Sections A join the midsection 60 to the ribs 62, 64 and sections B are provided on ribs 62, 64 proximate end surfaces 66, 68. As best shown in Figures 4 and 5, the hinge joint 19 also has radiused sections C and D. Sections C are provided at the interface between the latch arm and the hinge joint. Sections D are provided at the interface between the housing and the hinge joint. Each of the radiused section C and D extend from the first end surface 66 of the hinge joint to the second end surface 68. The radiused sections C and D, therefore, cooperate with and are integral with the midsection 60 and the ribs 62, 64. Ribs 62, 64 and radiused sections A, B, C and D are provided to reduce and distribute the stresses associated with the function of the latch arm across the entire width of the hinge joint. The distribution of stresses reduces the potential of hinge joint breakage and eliminates stress concentration of the hinge joint. In the embodiment shown, the radiused sections A and B have a radius in the range of 0.0127 to 0.0254 cm (0.005" to 0.010") and the radiused sections C and D have a radius in the range of 0.03810 to 0.05080 cm (0.015" to 0.020"). The ribs 62, 64 extend beyond the sidewalls of the midsection by a distance of between 0.0254 to 0.03810 cm (0.010" to 0.015"). This configuration is considered optimum for the connector illustrated in the drawings. In connectors of this type, the hinge joint 19 is subjected to various forces including pull-out forces and displacement forces. The pull-out forces occur when the plug connector 4 is pulled away from the receptacle connector 2 without disengaging the latch arms. These pull-out forces have an axial component and a rotational component associated therewith. The displacement forces are the forces associated with the rotation of the latch arms from the mating position to the unmating position. Both the pull-out and displacement forces are transmitted to the hinge joint causing the hinge joint to be stressed. As each force is different, the stress distribution on the hinge joint varies for each force. Consequently, the optimum design for the hinge joint must be one which allows the for flexibility of the joint and which can accommodate the various stress distributions without failure. For the connector illustrated, this optimum design is described above. Although in the embodiment disclosed an optimum configuration of the hinge joint is presented, it is important to note that in other connectors different optimum ranges may be applicable. However, the basic configuration of the "dogbone" hinge joint would remain the same.

Claims: A connector housing (4) molded of plastic material and being matable with a corresponding connector housing (2) and having a pair of latch arms (22) on opposite sides thereof having respective latching members (23,25,34,36,38) at forward free ends thereof latchable with corresponding latching means (48,52,54) of the corresponding connector housing, the latch arms being joined to respective sides (18,20) of the housing at hinge joints (19) spaced a selected distance rearwardly from the forward free ends of the latch arms (22), wherein the hinge joints (19) have longitudinal axes which are substantially perpendicular to the latch arms (22) and have forwardly facing portions and rearwardly facing portions extending in the direction of said longitudinal axes and defining midsections (60) with first and second ends at opposite ends of the midsections (60); characterized in that first ribs (62) are positioned at said first ends of the midsections and second ribs (64) are positioned at said second ends of the midsections said ribs (62,64) being integrally attached thereto; and in that the first and second ribs (62,64) extend beyond sidewalls of the midsections (60) in a direction which is essentially perpendicular to the longitudinal axis of the midsections (60), and the midsections (60) and the first and second ribs (62,64) extend between, and are integrally attached to, the latch arms (22) and the connector housing (4), whereby as forces are applied to the latch arms (22, the associated stresses of the hinge joints (19) will be distributed to the first and second ribs (62,64) to prevent the failure of the hinge joints (19). A connector housing as recited in claim 1, further characterized in that first radiused sections are provided on the hinge joint (19), the first radiused sections providing the transition between the hinge joint and the latch arm (22). A connector housing as recited in claim 2, further characterized in that second radiused sections are provided on the hinge joint (19), the second radiused sections providing the transition between the hinge joint (19) and the housing (4). A connector housing as recited in claim 1 further characterize in that third radiused sections are provided on the hinge joint (19), the third radiused sections provide the transition between the midsection (60) and the first and second ribs (62,64). A connector housing as recited in claim 4 further characterized in that fourth radiused sections are provided on the hinge joint (19), the fourth radiused sections are provided on the first and second ribs (62,64) proximate end surfaces thereof. A connector housing as recited in claim 3 further characterized in that the radius of each of the first radiused sections is between 0.03810 cm and 0.05080 cm (0.015 inches and 0.020 inches). A connector housing as recited in claim 6 further characterized in that the radius of each of the second radiused sections is between 0.03810 cm and 0.05080 cm (0.015 inches and 0.020 inches). A connector housing as recited in claim 5 further characterized in that the radius of each of the third and fourth radiused sections is between 0.0127 cm and 0.0254 cm (0.005 inches and 0.010 inches). A connector housing as recited in claim 1 further characterized in that the first and second ribs (62,64) extend beyond the sidewalls of the midsection (60) by a distance between 0.0254 cm and 0.03810 cm (0.010 inches and 0.015 inches).

Inventors: HUTCHINSON RICHARD DEVONE JR, SELF DAINES MILFRED JR, TRULL MICHAEL PAUL, HUTCHINSON, RICHARD DEVONE, JR., SELF, DAINES MILFRED, JR., TRULL, MICHAEL PAUL
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1992
Main classification: H01R13
IPC codes: H01R13