Patent Publication Number: US-6663412-B2

Title: Structure for interlocking connectors

Description:
FIELD OF THE INVENTION 
     The present invention relates to a structure for causing a base connector to interlock with a socket connector having wire ends secured thereto, wherein the base connector is surface mounted on a printed circuit board. 
     PRIOR ART 
     Examples of such a locking structure have been known in the art as disclosed in the specifications and drawings of U.S. Pat. Nos. 4,008,941 and 4,376,565. In each of those prior art structures, a socket housing has lock arms respectively disposed on its lateral sides. Each lock arm has at its distal end a hook capable of engaging with the corresponding one of detents that protrude from lateral sides of a base housing. Those lock arms further comprise certain push portions that will be pressed to release the hooks off the detents so as to break the interlocking relationship between said connectors. 
     It is however noted that those detents protruding sideways from the lateral sides of the base housing have inevitably caused an undesirably large overall size. Thus, it has considerably been difficult to render more compacted the couple of such connectors. 
     SUMMARY OF THE INVENTION 
     The present invention was made in view of these prior art structures, and its object is to provide a structure for interlocking connectors such that they can be made smaller in size, can engage one with another more reliably and can be manufactured less expensively. In particular, this structure provided herein must be adapted for employment in the shortish types of high-voltage connectors each having a reduced height. 
     In order to achieve the object, the present invention provides a structure for interlocking connectors, one of them being a socket connector that has a flat socket housing in which disposed side by side are socket contacts secured on respective wire ends. The other connector is a base connector of a shape to be surface mounted on a printed circuit board and comprising a flat box-shaped base housing for engagement with the socket housing, the base housing having a rear edge, similarly to the structure of this kind known in the art. Also similarly to the prior art, the socket housing in the invention has a pair of lock arms extending forwards from a rear end of the socket housing, and along lateral sides thereof. Tie pieces capable of elastic deformation and formed integral with the lateral sides of the socket housing do support and operatively connect the lock arms to said lateral sides. However, it is a characteristic feature of the present invention that the lock arms have their fore ends respectively formed integral with hooks projecting inwards and towards each other. Push lugs integrally extend back-wards from rear ends of the lock arms so as to be located rearwardly of the tie pieces. When engaging the connectors one with the other, the lock arms of the socket housing will be guided forwards along respective sides of the base housing until latched firmly in place by and with the rear edge thereof. 
     In a case wherein the interlocking structure is applied to a high-voltage connector assembly, each lock arm preferably has a fore extension protruding rearwardly of the rear edge of the base housing. Such fore extensions will protect sides of an array of leads that extend from respective pin contacts and project beyond said rear edge of the base housing. This structural feature will increase the linear distance between each pin contact and any electronic device located adjacent thereto, particularly between the pin contact&#39;s lead and said device, so as to improve the connector assembly in its resistance to high voltages. Preferably, each lock arm having and including such an integral fore extension is generally of the same height as the base housing. 
     Also preferably, the lock arms of the socket housing respectively have rear extensions formed integral therewith. These extensions may project beyond a rear edge of the socket housing, such that these rear extensions having the push lugs formed integral therewith will also serve to protect sides of a group of the wire ends secured to and protruding from socket connector. Such elongated lock arms will make it easier to open or close the lock arms relative to the base housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a socket connector involved herein; 
     FIG. 2 is a plan view of the socket connector put into a fixed engagement with a base connector, duet to an interlocking structure of the present invention; 
     FIG. 3 is a cross section taken along the line  3 — 3  in FIG. 2; 
     FIG. 4 is a cross section corresponding to FIG. 3 but showing another embodiment of the invention; and 
     FIG. 5 is a perspective view of the socket connector in still another embodiment. 
    
    
     THE PREFERRED EMBODIMENTS 
     Now some embodiments of the present invention will be described in detail, referring to the drawings. 
     A socket connector involved in the present invention is shown as a perspective view thereof in FIG.  1  and generally indicated at the reference numeral  1 . As seen in FIG. 2 that is a plan view, the socket connector  1  is to be fitted on a mating base connector  21  that has been surface mounted on a printed circuit board  20 . These connectors are shown from another aspect in FIG. 3 that is a cross section taken along the line  3 — 3  in FIG.  2 . 
     As seen in FIG. 1, the socket connector  1  comprises a socket housing  2  that is of a flat and rectangular shape elongated sideways. Compartments  3  are rectangularly cylindrical portions arranged side by side and at regular intervals in the socket housing  2  so as to accommodate therein socket contacts  12  separated from each other (see FIG.  3 ). Each contact  12  is secured to one of wire ends  11 , with each compartment being a unit shaped to be a square cylinder. The socket housing  2  has opposite lateral sides  4  and  4 , and tie pieces  5  and  5  respectively formed integral therewith are capable of elastic deformation in a plane that includes such a flat housing. A pair of lock arms  6  and  6  respectively continuing from the tie pieces  5  and  5  are thus integral with the socket housing  2 . Each lock arm  6  extends from a rear edge  9  of the socket housing, along the side  4  and forwards beyond a fore edge  10  of this housing. A hook  7  facing inwards is formed integral with a fore end of each lock arm  6 . The tie pieces  5  each projecting sideways from the side  4  are located near the rear edge  9  of said socket housing  2 , so that a rearmost end of each lock arm  6  is formed as a push lug  8  disposed rearwardly of the tie piece  5 . The fore face  5   a  of each tie piece is composed of a tapered region and a convex region continuing therefrom. This is for the purpose of facilitating the tie piece to reversibly make an elastic and smooth deformation without any local stress imparted to the lock arm  6  being opened or closed. Such a fore face  5   a  of the tie piece  5  may alternatively be a simple concave region also effective to ensure a uniform distribution of stress. 
     On the other hand, a base housing  22  of the base connector  21  surface-mounted the printed circuit board  20  is of a structure and shape as shown in FIGS. 2 and 3. The base housing  22  is generally a flat box having an open fore wall and a closed rear wall  23 . Pin contacts  30  are embedded each in part in this housing  22 , due to the insert-molding process employed to form this connector  21 . Each pin contact  30  penetrating the rear wall  23  has a lead  31  projecting rearwards therefrom. This lead  31  is bent into an L-shape adapted for the soldering thereof to the printed circuit board  20 . Lateral sides  25  and  25  of this housing have reinforcement metals  26  and  26  respectively embedded in the fore regions of said sides  25 , such that each metal  26  has a fore end exposed to be soldered to the printed circuit board  20 . Further, a pair of protrusions  27  and  27  are in alignment with the respective sides  25  and  25  are formed integral with the rear wall  23  so as to jut out rearwardly thereof. 
     The socket connector  1  with the socket contacts  12  secured to the wire ends  11  and held in the compartments  3  will be fitted on and engaged with the base connector surface-mounted on the circuit board  20 , in a manner as will be seen in FIGS. 2 and 3. In detail, an operator may use his or her fingers to press inwards the push lugs  6  so that the forward regions of lock arms  6  will be displaced a little distance away from each other. Subsequently, these lock arms  6  will be guided along the respective sides  25  of the base housing  22 , until the socket housing  22  fits in the open fore wall of base housing  22 . Thus, the socket contacts  12  fit on the respectively mating pin contacts  30  to establish electric connection therewith. At the same time, both the hooks  7  on the lock arms  6  are latched by the protrusions  27  projecting from base housing  22 , whereby these arms  6  will firmly grip this housing  22  to thereby cause these connectors  1  and  21  to interlock one with another. 
     When pulling the socket connector  1  out of the base connector  21 , the push lugs  8  of lock arms  6  will be pressed towards each other with the operator&#39;s fingers so as to release the hooks  7  from the protrusions  27  of base connector. With the lock arms being kept for a while at this position, they  6  will be retracted back along the sides  25  of base housing  22  in order to easily and smoothly withdraw and remove the socket housing  2  from the base housing. 
     It will be understood that those protrusions  27  can be dispensed with, if the hooks  7  on lock arms  6  are shaped to directly catch the rear edge of base housing  22  so as to be locked thereby. 
     FIG. 4 shows a case wherein the interlocking structure of the invention is preferably applied to high-voltage connectors. In a second embodiment employed in this case, the lock arms  6  have each a fore extension  28  projecting from the base housing&#39;s  22  rear wall a longer distance than in the first embodiment. Each lock arm  6  having such an extension  28  is of a height substantially equal to that of said base housing  22  in order to protect the side of the lead  31  of each pin contact  30 . Linear distance between each lead  31  and any adjacent electronic device on the printed circuit board  20  will thus be increased to improve these connectors&#39; resistance to high voltages. 
     FIG. 5 shows another type of the socket connector provided in accordance with a third embodiment. In this case, each lock arm  6  has a rear extension projecting a considerable distance beyond the rear wall of socket housing  2 . The rear extensions will thus function as push lugs  8  that do not only facilitate the opening and closing of lock arms  6  with use of the operator&#39;s fingers, but also provide a better protection to the wire ends  11 . 
     In summary, the pair of elongated lock arms extending along the sides of socket housing will slide along the respective sides of a base housing, so that these connectors can easily and smoothly fit one on another to establish an electic connection, without fear of any torsional mutual engagement. The socket housing&#39;s lock arms strongly grip the base housing, ensuring a reliable locking thereof in said socket housing. 
     The hooks on the socket housing&#39;s lock arms are designed to be directly latched by a rear edge itself, or indirectly by its rearward but non-sideways protrusions of the base housing. Any lugs or protrusions projecting sideways need no longer be formed on the lateral sides of said base housing. Any existing types of base connectors lacking in such sideways lugs or protrusions can now be employed herein to rendering less expensive the interlocking structure of the invention.