Electrical connector structure with release and locking mechanism
BACKGROUND OF THE INVENTION 
     The present invention relates generally to an electrical connector structure wherein male and female connectors are coupled to connect the male and female pins thereof and more specifically relates to an electrical connector structure wherein mutual release and locking of the male and female connectors are facilitated by the lever action of a snap member associated with the male connector. 
     The same Applicant has filed Japanese Utility Model Registration Ser. No. 58-51425 filed on Apr. 8, 1983. 
     The disclosure of this Utility Model Registration No. 58-51425 is hereby incorporated by reference and will be described hereinbelow with reference to FIGS. 1 through 6. 
     In these drawings, symbol A denotes a male connector and B denotes a female connector. Numeral 2 denotes a flat flexible cable. The male connector A is provided with a plurality of male connector pins 1 extending longitudinally through a frame 16 which is transversely elongated. On the other hand, the female connector B connected to a flat flexible cable is provided with a plurality of female connector pin holes (not shown) to be connected individually with the male connector pins 1. The male connector A is formed with side walls 17, 18 disposed parallel to each other longitudinally on the front and rear sides of the frame 16 at each end thereof with a clearance therebetween for guiding the female connector B into proper alignment with the male connector pins 1 to ensure accurate insertion of the male connector pins 1 into the corresponding female pin holes. 
     A snap member 6 is interposed between the left and right side walls 17, 18 as denoted by 6l and 6r. The bottom of each snap member 6 is provided with a gear-tooth-shaped groove 21. A hole 5 extending between the side walls 17, 18 is located above the groove 21. An axle 4l, 4r is fitted into each of the corresponding holes 5 and also guidably fitted into an oblique, elongated groove 24l, 24r which is parallel to a rolling surface 23 at the base of the male connector A. As shown in FIG. 4, when the male and female connectors A and B are fitted to each other and locked by means of each engagement pawl 7l, 7r, the snap member 6 is in contact with the rolling surface 23 at a point C near an upwardly projecting finger 8 of the snap member 6. 
     It should be noted that the axle 4l, 4r is located at a center of radius of curvature formed at the bottom surface of the snap member. 
     As the snap member 6 is pivoted on the axle 4l, 4r outward as seen in FIG. 5, the contact point is moved from the point C to a point D. 
     When the snap member 6 is pivoted to its outward limit of travel, the contact point is further moved from the point C to a point E as shown in FIG. 6. As this movement is being carried out, the supporting axle 4l, 4r of each snap member 6 translates outward within the corresponding groove 24l, 24r. In order for each snap member to pivot smoothly without slipping, it is desirable that the groove 21 of each snap member 6 engage a gear-tooth-like projection on the rolling surface 23 of the frame 16. As shown in FIGS. 4 to 6, since the distance through which each snap member 6 pivots is short, one tooth is sufficient for this pivotal movement. 
     In this approach, the distance between the contact points C, D, E and the upwardly extending finger 8l, 8r increases as the distance through which the snap member 6l, 6r is pivoted increases. However, the distance therefrom to the top end 14l, 14r of each snap member 6l, 6r remains substantially unchanged. Therefore, at the beginning of pivotal movement in the opening direction of the snap members 6l, 6r, the leverage is so great that a relatively light pivotal force on the snap members 6l, 6r is needed to displace the female connector B out of engagement with the male connector A. The leverage decreases as the female connector pins are removed from the corresponding male connector pins 1 to a minimum at the limit of outward travel of each snap member 6. Therefore, the distance through which the female connector B is moved per unit of displacement of each snap member 6 increases. This is acceptable since when the male connector pins l are not engaging the corresponding female connector pins, only a light pivoting force is required in spite of the above-described decrease in leverage. 
     However, such an electrical connector has the disadvantage that the upwardly projecting fingers 8l, 8r can easily disengage from the bottom edge of the female connector B as appreciated from FIG. 6 when the corresponding snap member 6l, 6r is fully pivoted to detach the female connector pin holes from the corresponding male connector pins. 
     SUMMARY OF THE INVENTION 
     With the above-described disadvantage in mind, it is an object of the present invention to provide an improved space-saving electrical connector structure which allows easier and securer separation of the female connector pin holes from the male connector pins without extra pivoting force on the pair of snap members and without slipping of an operator&#39;s finger touching the top end of one of the snap members when he pivots the snap member through his finger and which can guide the female connector into the male connector with a single operation without causing each snap member to pivot inwardly. 
     This can be achieved by providing an electrical connector in which a supporting axle of each snap member is located between a sector-shaped bottom surface of the snap member and center of curvature of the sector so as to allow pivotal movement of the snap member about the supporting axle which travels along substantially vertically elongated holes provided in the side walls as the snap member is pivoted and/or a knurled edge and rib extended along the knurled edge are provided at the top end of the snap member for guiding the female connector toward the male connector pins so as to align the pin holes of the female connector with the male connector pins. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A more complete understanding of the present invention may be obtained from the following description in conjunction with the attached drawings in which like reference numerals designate corresponding elements and in which: 
     FIGS. 1 through 6 show an electrical connector structure disclosed in Japanese Utility Model Registration Ser. No. 58-51425; 
     FIGS. 7 through 12 show a first preferred embodiment of an electrical connector structure according to the present invention in which FIG. 7 is a perspective view of a male connector, FIG. 8 is a partially sectioned plan view of male and female connectors when they are about to be connected to each other, FIG. 9 is a perspective view of a snap member, FIG. 10 is a plan view in partial section of the male and female connectors when they are completely connected to each other, and FIGS. 11 and 12 are plan views in partial section of the male and female connectors as they are being separated from each other; and 
     FIGS. 13, 14 and 15 show a second preferred embodiment of an electrical connector according to the present invention in which FIG. 13 is a perspective view of the male connector, and FIGS. 14 and 15 are plan views in partial section of the male and female connectors as they are being connected to each other. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference will hereinafter be made to the drawings in order to facilitate understanding of the present invention. 
     FIGS. 7 through 12 show a first preferred embodiment of the present invention. 
     As shown in FIGS. 8 through 12, the base of each snap member 6 (6l, 6r) has a portion substantially in the form of a circular arc about a point F and the supporting axle 4l, 4r of each snap member 6l, 6r is guidably inserted into corresponding vertically elongated holes 25l, 25r penetrating both the front and rear walls of the male connector A, i.e., frame 16. 
     As shown in FIG. 10, when the female connector B is tightly secured to the male connector A, the bottom surfaces of the snap members 6 (6l, 6r) are in contact with the rolling surfaces 23 of the frame 16 at points C near the upwardly projecting fingers 8 (8l, 8r). In addition, each engagement pawl 7l, 7r is received by a corresponding recess 3l, 3r of the female connector B. 
     In addition, as shown in FIG. 11 as each snap member 6l, 6r is pivoted in its opening direction (outwardly), the above-described contact point shifts to point D and continues to point E when the snap members 6l, 6r reach their outward limit substantially as shown in FIG. 12. 
     It should be noted that although the corresponding supporting axle 4l, 4r tends to be translated outward with respect to the frame 16 as each snap member 6l, 6r is pivoted, the corresponding supporting axle 4l, 4r can move only in the vertical direction due to the limitation set by the corresponding vertically elongated hole 25l, 25r. The supporting axles 4l, 4r move downward as the snap members 6l, 6r are pivoted from the positions shown in FIG. 10 to that shown in FIG. 11 and then move upward as the snap members 6l, 6r are pivoted from the positions shown in FIG. 11 to the substantially final state shown in FIG. 12. To achieve this two-stage movement of each supporting axle 4l, 4r, the positions of the point E and supporting axles 4 and the stroke of the snap members 6l, 6r are selected. 
     The distance from the rolling contact point to the upwardly projecting finger 8l, 8r increases as the corresponding snap member 6l, 6r is pivoted toward the fully open (outward limit) position. However, the distance from the above-described contact points C, D, and E to the upper end 14 (14l, 14r) of the corresponding snap member 6l, 6r remains substantially unchanged. Therefore, at the beginning of the pivotal movement of each snap member 6l, 6r toward its fully open position, the leverage is so great that a light pivoting force on each snap member 6l, 6r permits the snap member 6l, 6r to remove the female connector B from the male connector A. The leverage decreases at the position at which the female connector pins (not shown) separate from the correspondingly fitted male connector pins 1 and as the snap members 6l, 6r are pivoted toward their fully open positions. Therefore, the amount of movement of the female connector B per unit of pivotal movement of each snap member 6l, 6r is accordingly increased. At this time, since the female connector pin holes do not substantially engage the corresponding male connector pins 1, only a light pivoting force on the snap members 6l, 6r is required. 
     In any case, the above-described pivotal movement of each snap member 6l, 6r is achieved with the base of each snap member being in sliding contact with the rolling surface 23 of the frame 16 since the corresponding supporting axle 4 is guided along the vertically elongated holes 25. Therefore, the total horizontal displacement of the snap members 6l, 6r is small even at the limit of vertical travel of the corresponding upwardly projecting finger 8. That is to say, there is no danger of the snap members 6l, 6r slipping off or separating from the bottom edge of the female connector B. On the other hand, since the supporting axle 4l, 4r of each snap member 6l, 6r can be set to stop at the upper end of the corresponding vertically elongated hole 25 when the female connector B is tightly fitted to the male connector A as shown in FIG. 10, the female connector B can be maintained at the tightly secured state with the aid of each engagement pawl 7 (7l, 7r). 
     In this embodiment, the leverage is increased to reduce the force required to pivot the snap members 6l, 6r from the beginning of their pivotal movement, which is relatively heavy and thereafter the leverage decreases as each snap member 6l, 6r approaches its fully open position, thus the stroke of the female connector B being increased without allowing the snap members 6l, 6r to project only minimally from the corresponding edge of the frame. This contributes to the space saving of the connector. 
     FIGS. 13 through 15 show a second preferred embodiment of the present invention. 
     As in the previous embodiment, the snap members 6l, 6r are axially supported so as to allow pivotal movement in opposite directions, and the female connector B is held in engagement with the male connector A when they are pivoted to their fully closed positions and is disengaged therefrom when they are pivoted to their open positions. In this embodiment, the snap members 6l, 6r also have knurled edges 9l, 9r along their top ends for preventing finger slippage when an operator pivots the snap member 6l, 6r with his finger and ribs 10l, 10r projecting substantially vertically from the corresponding knurled edge to allow the female connector B to slide smoothly toward the corresponding male connector. 
     As shown in FIG. 13, the knurled edges 9l, 9r are formed along the top end of each snap member 6l, 6r to prevent the operator&#39;s fingers from slipping when he or she pivots the snap members to release the connectors. The ribs 10l, 10r stand slightly higher than the top edges of the corresponding knurled edges 9l, 9r and are much narrower than the knurled edges 9l, 9r. In FIGS. 14 and 15, symbol G denotes a leading corner of the female connector B with respect to insertion in the corresponding male connector A and numerals 4l, 4r denote the supporting axle about which the corresponding snap member 6l, 6r pivots. The engagement pawl 7l, 7r projects from the inward end of the corresponding knurled end 9l, 9r and serves to secure the female connector B tightly to the male connector A after the corresponding snap member 6l, 6r is moved to its fully closed position. 
     When the operator tries to insert the female connector B into the male connector A with the snap members 6l, 6r in the closed position (normal rest position) as shown in FIG. 14, the leading corner G of the female connector B first contacts the corresponding rib 10l, 10r since the ribs 10l, 10r are slightly higher than the knurled edges 9l, 9r. If the female connector B is moved further toward the male connector A, the snap members 6l,  6r are forceably pivoted in the opening direction as the corner G of the female connector B slides along on the corresponding rib 10l, 10r smoothly. Thereafter, as shown in FIG. 15, the female connector B can be inserted into the male connector A without contact with the ribs 10l, 10r. 
     It should be noted that although in this embodiment, the ribs 10l, 10r are centered on the width of the knurled edges 9l, 9r, the same function can be achieved from any position on the knurled edges 10l, 10r. In addition, the width of the ribs 10l, 10r is arbitrarily selected. 
     In this way, the electrical connector of the second preferred embodiment allows the female connector B to be inserted into the male connector A simply by moving the female connector B toward the male connector A, even if the snap members 6l, 6r are in the closed position. That is to say, the female connector B can be inserted into the male connector A with a single operation. 
     Although in the first preferred embodiment shown in FIGS. 7 through 12, the top ends 14l, 14r of the left and right snap members 6l, 6r are not formed with the knurled edges 9l, 9r and ribs 10l, 10r as in the second preferred embodiment, the top end thereof may be formed with the knurled edges 9l, 9r and ribs 10l, 10r. 
     As described hereinbefore, the electrical connector can allow engagement of the female connector with the male connector and removal of the female connector from the male connector with a single operation. 
     It will clearly be understood by those skilled in the art that the foregoing description is in terms of preferred embodiments of the present invention and various changes and modification may be made without departing from the scope of the present invention which is to be defined by the appended claims.