Double lock type electrical connector
FIELD OF INVENTION 
     The present invention relates to a double-lock electrical connector comprising an insulating housing having contact receiving cavities and a double-lock member installed in the insulating housing for retaining contacts by locking members in contact receiving cavities and the double-lock member. 
     BACKGROUND OF THE ART 
     A conventional double-lock electrical connector comprises an insulating housing having a plurality of contact receiving cavities defined by isolation walls and a double-lock member to be mounted on the insulating housing in perpendicular relationship to the longitudinal direction of the contact receiving cavities. The double-lock member has contact insertion openings corresponding to the contact receiving cavities in the insulating housing. In such a double-lock electrical connector, the double-lock member is brought into a preliminary locking position relative to the insulating housing before being moved to a final locking position. In this manner, each contact is locked by a locking member within the respective contact receiving cavity as well as by the double-locking member, thereby achieving double locking of the contact for assured retention. 
     In a double-lock electrical connector, a housing of a matable connector may not always mate straightly. That is, the matable connector tends to mate in a slanted manner, thereby making the mating operation difficult or time consuming. In order to overcome this problem, there is proposed a double-lock electrical connector having an insulating housing and a double-lock member formed with guide grooves for guiding ribs on the housing of a matable connector, thereby achieving smooth mating of the matable connector. 
     Unfortunately, however, the double-lock member is typically made from plastic material by injection molding. Thinned portions of the molded double-lock member&#39;s guide grooves are cooled faster than the other portions of the double-lock member. Thus non-uniform cooling of the double-lock member exists. On the other hand, if designed to achieve uniform cooling for minimizing deformation, no guide grooves can be formed. 
     It is, therefore, an object of the present invention to provide a double-lock electrical connector provided with a double-lock member for improved mating operation and minimum deformation. 
     SUMMARY OF THE INVENTION 
     In order to achieve the above object, the double-lock electrical connector according to the present invention has a housing provided with first guide grooves extending in the mating direction to guide a matable connector housing and a double-lock member insertion cavity in perpendicular relation relative to the mating direction. The insertion cavity is formed behind a double-lock member insertion mouth in communication with the first grooves. Also, the double-lock member has second guide grooves in communication with the first guide grooves when installed in the housing for guiding the matable connector housing. The improvement resides in that the double-lock member is provided with end walls that in continuous with the sidewalls of the second guide grooves at the end portions thereof and engaging portions on the end walls to engage with the housing. 
     The double-lock electrical connector according the present invention is provided with first and second guide grooves to guide a matable connector housing, thereby allowing smooth mating with such matable connector and improving the mating operation. Additionally, the end walls are continuously formed with the sidewalls of the second guide grooves which help to achieve a more uniform cooling of the molded connector as compared with the conventional design, thereby minimizing deformation because of more uniform contraction during cooling. 
     Now, the double-lock electrical connector according to the present invention will be described hereunder in detail with reference to the accompanying drawings illustrating one embodiment thereof. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a cross sectional view of one embodiment of the double-lock electrical connector according to the present invention. 
     FIG. 2 is a bottom view of the insulating housing of the double-lock electrical connector in FIG. 1 as seen from the direction of the arrow A. 
     FIG. 3 is a cross sectional view of the insulating housing in FIG. 2 along the line 3--3. 
     FIG. 4 is a bottom view of the double-lock member of the double-lock electrical connector in FIG. 1 as seen from the direction of the arrow A. 
     FIG. 5 is the double-lock member in FIG. 4 as seen from the direction of the arrow D. 
     FIG. 6 is the double-lock member in FIG. 4 as seen from the direction of the arrow C. 
     FIG. 7 is a cross sectional view of the double-lock member along the line 7--7 of FIG. 4. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A double-lock electrical connector 10 as illustrated in FIG. 1 is a male type connector containing a plurality of female (receptacle) contacts 12 and comprises an insulating housing 20 and a double-lock member 40. The double-lock electrical connector 10 is designed to mate with a matable female connector (not shown) having a plurality of male contacts by moving it in the mating direction (represented by F), thereby making electrical connection or engagement between the male contacts in the female connector and female contacts 12 in the double-lock electrical connector 10. 
     The insulating housing 20 is formed with a plurality of contact receiving cavities 22. A male contact insertion passage 26 is formed in each contact receiving cavity 22 in communication therewith in a wall 24 at the front end portion in the mating direction. On the other hand, an opening 28 is formed at the rear end portion in the mating direction for insertion of each female contact 12. The top wall in each contact receiving cavity 22 is formed with an engaging projection 30 projecting inwardly. Also, the bottom wall is formed with an engaging recess 32 at the location corresponding to the engaging projection 30. In mating with the matable female connector (not shown), ribs (not shown) are formed in the housing of the female connector for guiding it, thereby allowing smooth mating of both connectors in the mating direction along the two guide grooves 34. Also, a double-lock member insertion mouth 36a is formed at the center portion of the insulating housing 20 in communication with the two guide grooves 34 for inserting the double-lock member 40 into the double-lock member receiving cavity 36. 
     At the front end portion of the contact 12 received in the contact receiving cavity 22, there is formed a contact engaging (or locking) portion 14 to engage with the engaging projection 30 for protecting the backing out of the contact. A contact engaging portion 16 engages the engaging recess 32 for protecting forward removal of the contact. 
     The double-lock member 40 is formed with contact insertion openings 42 in corresponding relation to the contact receiving cavities 22. When the double-lock member 40 is latched to a preliminary locking position (the position represented by the double-chain line 40a in FIG. 1) of the insulating housing 20, the female contacts 12 are inserted into the contact receiving cavities 22. Subsequently, the double-lock member 40 is latched to a preliminary locking position (the position represented by the double-chain line 40a in FIG. 1). Also, the double-lock member 40 is formed with guide grooves 44 at the locations corresponding to the two guide grooves 34 in the insulating housing 20, thereby guiding the ribs on the housing of the female connector received in the guide grooves 34 when the double-lock member 40 is locked into the final locking position. As a result, the double-lock electrical connector 10 and the female connector mate smoothly with each other to improve their mating operation. 
     It is to be noted that end walls 48 are formed at the end portions of the guide grooves in the double-lock member 40 in continuation with the sidewalls 46 of the guide grooves 44. Cantilever lances (engaging portions) 50 comprising base ends 50a and free ends 50b are formed on the end walls 48 to define slots 52 between the other ends 50b and the walls 48a. As the double-lock member 40 is inserted into the double-lock member receiving cavity 36 through the double-lock member insertion mouth 36a, the lances 50 are deflected but recover to their original (non-deflected) position when the double-lock member 40 is inserted to the preliminary locking position, thereby locking it to the wall 20a of the insulating housing 20. The double-lock member 40 is, then, prevented from backing out of this position. When the double-lock member 40 is moved to its final locking position, the projections 54 are latched to the engaging portions 38 in the insulating housing 20. 
     The double-lock member 40 is made from a plastic material by injection molding. However, it is found that the provision of the end walls 48 in continuation with the sidewalls 46 of the guide grooves 44 assures more uniform cooling as compared with the conventional double-lock member. Additionally, the lances 50 formed on the end walls 48 provide reliable locking or retention of the double-lock member 40 in the insulating housing 20. 
     As apparent from the foregoing description, the double-lock member of the double-lock electrical connector features the provision of the end walls in continuation with the sidewalls of the second guide grooves, thereby achieving more uniform cooling of the molded double-lock member and minimizing deformation as compared with the conventional double-lock member.