Abstract:
A connector to which an object is to be connected, includes an insulator having at least one contact support groove, and at least one contact which is fixed to the insulator by being inserted into the contact support groove, the contact being contactable with the object after the object is inserted into the insulator. The insulator includes at least one holding portion formed as one of a recess and a through-hole, which is communicatively connected with the contact support groove, and the contact includes a locking protrusion, which comes into engagement with the holding portion to hold the contact to the insulator when the contact is inserted into the contact support groove.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present invention is related to and claims priority of the following co-pending application, namely, Japanese Patent Application No. 2008-112119 filed on Apr. 23, 2008. 
     FIELD OF THE INVENTION 
     The present invention relates to a connector. 
     BACKGROUND OF THE INVENTION 
     The connector disclosed in Japanese Unexamined Patent Publication 2008-60087 is provided with a housing (insulator) having a plurality of contact support grooves (insertion grooves), a plurality of contacts which are respectively inserted into the plurality of contact support grooves by press-fitting, and a slider (actuator) supported by the housing. 
     Since a fixed portion in the shape of a projection projects from a side of each contact, inserting each contact into a corresponding contact support groove by press-fitting causes the fixed portion of this contact to be pressed against a side surface of associated one of a plurality of partition walls, defining the plurality of contact support grooves, to thereby be wedged into the side surface. Thereupon, a wedging force occurs between each fixed portion and the associated partition wall, thus preventing each contact from unexpectedly coming out of the associated contact support groove. 
     In recent years, there have been growing trends to miniaturize connectors and to narrow the pitch of contacts due to the recent trend of multi-contact design. Accordingly, in connectors produced in recent years, partition walls that form a plurality of contact support grooves therebetween are thin compared with those of conventional ones, thus becoming easy to deform plastically or elastically. If the partition walls are easily deformed, the fixed portion of each contact cannot be easily wedged into the associated partition wall, which reduces a holding force acting on the contact by the associated support groove (partition wall) to hold the contact therein. 
     Additionally, if each partition wall is thin, a stress applied to each partition wall which is caused by press-fitting the plurality of contacts into the corresponding plurality of contact support grooves cannot be sufficiently dispersed and thus remains, so that there is a possibility of the entire housing becoming warped. Specifically, if reflow soldering is performed when each contact is soldered to a circuit board, reflow heat is transmitted to the housing, so that there is a possibility of the housing becoming largely warped by the residual stress. This kind of warping of the housing becomes a cause of a failure in mounting of the contacts to the circuit board. 
     SUMMARY OF THE INVENTION 
     The present invention provides a connector, which is structured to be capable of firmly holding each contact to an insulator without deforming the insulator. 
     According to an aspect of the present invention, a connector is provided to which an object is to be connected, including an insulator having at least one contact support groove; and at least one contact which is fixed to the insulator by being inserted into the contact support groove, the contact being contactable with the object after the object is inserted into the insulator. The insulator includes at least one holding portion formed as one of a recess and a through-hole, which is communicatively connected with the contact support groove, and the contact includes a locking protrusion, which comes into engagement with the holding portion to hold the contact to the insulator when the contact is inserted into the contact support groove. 
     According to the present invention, the contact is firmly held by the insulator because the locking protrusion that protrudes from the contact is engaged with the holding portion that is formed of the insulator when the contact is inserted into the contact support groove of the insulator. 
     Moreover, the locking protrusion does not press the associated side surface in the contact support groove after the completion of the contact into the contact support groove of the insulator, and accordingly, the insulator is not subjected to mechanical stress, thus not being deformed thereby. 
     It is desirable for a plurality of the contact support grooves to be arranged in a predetermined direction, wherein a plurality of the contacts are inserted into the plurality of contact support grooves, respectively, a plurality of the holding portions are communicatively connected with the plurality of contact support grooves, respectively, and are provided at alternately different positions in a lengthwise direction of the plurality of contact support grooves to be arranged in a zigzag fashion, and the locking protrusion is formed on each of the contacts, so that the locking protrusions of the contacts come into engagement with the holding portions when the contacts are inserted into the contact support grooves, respectively. Accordingly, a reduction in mechanical strength of the insulator caused by the formation of the plurality of holding portions can be minimized compared with the case where the plurality of holding portions are formed to be arranged along on a given straight line. In addition, the flowability (moldability) of synthetic resin of the insulator when the insulator is molded by injection molding is enhanced. 
     It is desirable for the locking protrusion to protrude from one of two lateral sides of the contact, and for the holding portion to be formed on one of two lateral sides of the contact support groove, which faces the one lateral side of the contact. 
     If the locking protrusion is formed on a top surface of the second arm while the holding portion with which the locking protrusion is engaged is formed on a bottom surface (inner surface) of a top plate portion of the insulator, the second arm becomes immovable relative to the first arm. Therefore, even if the connector having this sort of structure is equipped with the actuator, the second arm cannot be moved by the actuator. 
     However, if an actuator, which moves one end of the second arm toward the inserted object by pressing the other end of the second arm in a direction away from an adjacent one end of the first arm with the object being inserted in between the other end of the first arm and the one end of the second arm, is applied to a connector which is structured so that the locking protrusion protrudes from one of two lateral sides of the contact and so that the holding portion is formed on one of two lateral sides of the contact support groove which faces the one lateral side of the contact, one end of the second arm can be moved by the actuator toward the object which is to be connected to the contact. Accordingly, through the use of this actuator, the first arm and the second arm can be reliably pressed against (can be connected to) the object to be connected. 
     It is desirable for a top surface of the locking protrusion to face a top surface of the holding portion while a bottom surface of the contact is in contact with a bottom of the contact support groove. 
     It is desirable for the locking protrusion to protrude from one of a top surface and a bottom surface of the contact, and for the holding portion to be formed on one of a top surface and a bottom surface of the contact support groove. Accordingly, the position of the contact relative to the insulator can be securely fixed. 
     It is desirable for an engaging portion to be formed on the contact at a position different from a position of the locking protrusion in a lengthwise direction of the connector, wherein a surface of the locking protrusion which faces the engaging portion faces an inner surface of the holding portion, and a surface of the engaging portion which faces the locking protrusion is in contact with the insulator. Accordingly, the contact can be securely prevented from deviating relative to the insulator in the lengthwise direction of the contact regardless of the insertion direction of the contact into the insulator. 
     It is desirable for the actuator to include at least one cam positioned between the adjacent end of the first arm and the other end of the second arm, a movement of the actuator relative to the insulator causing the cam to press the other end of the second arm to thereby move the one end of the second arm toward the other end of the first arm. 
     It is desirable for the actuator to include a pair of pivots which project in opposite directions from laterally opposite ends of the actuator, respectively, wherein the actuator is rotatable about the pair of pivots relative to the insulator. 
     In an embodiment, a connector is provided, including an insulator having a plurality of contact support grooves, and a plurality of contacts which are fixed to the insulator by being inserted into the plurality of contact support grooves, respectively, each of the contacts having two prongs for holding an object which is to be connected to the contact therebetween. The insulator includes a plurality of locking holes formed in the contact support grooves, respectively. Each of the contacts includes a locking protrusion which comes into engagement with the locking hole formed in associated one of the contact support grooves when the contacts are inserted into the contact support grooves, respectively. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be discussed below in detail with reference to the accompanying drawings, in which: 
         FIG. 1  is a front perspective view of an embodiment of a connector according to the present invention, viewed obliquely from above; 
         FIG. 2  is an exploded front perspective view of the connector, viewed obliquely from above; 
         FIG. 3  is a rear perspective view of the connector, viewed obliquely from below; 
         FIG. 4  is a front elevational view of the connector; 
         FIG. 5  is a cross sectional view taken along the line V-V shown in  FIG. 4 ; 
         FIG. 6  is a cross sectional view taken along the line VI-VI shown in  FIG. 5 ; 
         FIG. 7  is a cross sectional view taken along the line VII-VII shown in  FIG. 5  when the rotational actuator is in an unlocked position; 
         FIG. 8  is a cross sectional view taken along the line VIII-VIII shown in  FIG. 5  when the rotational actuator is in the unlocked position; 
         FIG. 9  is a cross sectional view similar to that of  FIG. 8  when the rotational actuator is in a locked position; 
         FIG. 10  is an enlarged front perspective view of a second contact, viewed obliquely from above; 
         FIG. 11  is a cross sectional view similar to that of  FIG. 7 , showing a modified embodiment of the connector; 
         FIG. 12  is an enlarged rear perspective view of a first contact of another modified embodiment of the connector, viewed obliquely from above; 
         FIG. 13  is a cross sectional view taken along the line XIII-XIII shown in  FIG. 12 ; 
         FIG. 14  is an enlarged rear perspective view of a first contact of yet another modified embodiment of the connector, viewed obliquely from above; 
         FIG. 15  is a cross sectional view taken along the line XV-XV shown in  FIG. 14 ; 
         FIG. 16  is a cross sectional view similar to that of  FIG. 7 , showing yet another modified embodiment of the connector; 
         FIG. 17  is an enlarged cross sectional view of a portion of the embodiment of the connector shown in  FIG. 16 , showing a state of engagement between a locking protrusion and the associated locking hole; and 
         FIG. 18  is an enlarged cross sectional view similar to that of  FIG. 17 , showing a state of engagement between another embodiment of the engaging projection and the associated locking hole. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An embodiment of a connector according to the present invention will be hereinafter discussed with reference to  FIGS. 1 through 10 . In the following descriptions, forward and rearward directions, leftward and rightward directions, and upward and downward directions of the connector  10  are determined with reference to the directions of the double-headed arrows shown in the drawings. 
     The connector  10  is for use with a FPC (Flexible Printed Circuit). The connector  10  is provided, as relatively large elements thereof, with an insulator  20 , two (left and right) anchors  35 , a series of first contacts  40 F, a series of second contacts  40 R and a rotational actuator  50 . 
     The insulator  20  is made of electrical-insulative and heat-resistant synthetic resin by injection molding. The insulator  20  is provided with a pair of (left and right) sidewall portions  21 , a bottom plate portion  22  and a top plate portion  23 . The bottom ends of the pair of side wall portions  21  are connected to each other via the bottom plate portion  22 , and the top ends of front halves of the pair of side wall portions  21  are connected to each other via the top plate portion  23 . 
     The insulator  20  is provided between the bottom plate portion  22  and the top plate portion  23  with a total of sixteen partition walls  24  which are formed integral with the insulator  20  and arranged at regular intervals in the leftward/rightward direction. Each partition wall  24  extends substantially in the vertical direction of the insulator  20  and is provided on the front of the partition wall  24  with an insertion recess  24   a , which is recessed rearward (see  FIGS. 7 through 9 ). The rear end of each partition wall  24  is positioned behind the rear end of the top plate portion  23  in the forward/rearward direction (see  FIGS. 2 and 7  through  9 ). In addition, as shown in  FIG. 5 , a portion of the left side surface of each partition wall  24  in the area close to the rear end thereof protrudes leftward to be positioned to the left of the remaining portions (front and rear portions) of the same side surface in the leftward/rightward direction to serve as a flat support surface  25 . Additionally, adjacent surfaces of the sixteen partition walls  24  in the leftward/rightward direction are provided in the vicinity of the rear ends of the partition walls  24  with guide recesses  24   b  for leading the series of first contacts  40 F and the series of second contacts  40 R into the insulator  20  when the series of first contacts  40 F and the series of second contacts  40 R are inserted into the insulator  20 . 
     The connector  10  is provided between adjacent partition walls  24  with a total of eight first contact support grooves  26 F and a total of seven-second contact support grooves  26 R each of which is elongated in the forward/rearward direction. As shown in the drawings, the first contact support grooves  26 F and the second contact support grooves  26 R are alternately arranged. The bottom plate portion  22  is provided on a top surface thereof with a total of fifteen recessed grooves which are recessed downward and elongated in the forward/rearward direction to serve as the bottom ends of the first and second contact support grooves  26 F and  26 R, respectively, while the top plate portion  23  is provided on a lower surface (inner surface) thereof with a total of fifteen recessed grooves which are recessed upward and elongated in the forward/rearward direction to serve as the top ends of the first and second contact support grooves  26 F and  26 R, respectively. 
     As shown in  FIGS. 3 and 5  through  9 , the insulator  20  is provided with a total of fifteen locking holes (holding portions)  27  and  28 , each of which is formed in a manner so that the bottom end of the right side surface of the associated partition wall  24  is recessed leftward and that a through-hole is formed through a portion of the bottom plate portion  22  which is communicatively connected with this recessed portion to extend vertically. As shown in the drawings, each locking hole  27  and each locking hole  28  are communicatively connected with the associated first contact support groove  26 F and the associated second contact support groove  26 R, respectively. The number of the locking holes  27  is eight and the number of the locking holes  28  is seven. The seven locking holes  28  are positioned behind the eight locking holes  27  in the forward/rearward direction. 
     The bottom plate portion  22  is provided, on portions of the bottom surface thereof at the rear end of this bottom surface with a total of fifteen locking recesses  29 , at positions immediately below the rear ends of the fifteen contact support grooves (the eight first contact support grooves  26 F and the seven second contact support grooves  26 R), respectively. The left and right side wall portions  21  are provided at the rear thereof on inner side surfaces thereof with two (left and right) bearing recesses  30 , respectively. 
     The insulator  20  is provided at the front ends of the left and right side wall portions  21  with two (left and right) anchor-receiving recesses  31 , respectively, which are recessed rearward. Each anchor  35  is provided with a tail portion  36 , which lies substantially horizontal. The rear ends of the left and right anchors  35  are fitted into the left and right anchor-receiving recesses  31  from the front thereof, respectively. 
     Each of the eight first contacts  40 F and the seven second contacts  40 R is molded of a thin base material made of a resilient copper alloy (e.g., phosphor bronze, beryllium copper, titanium copper) or a resilient Corson-copper alloy by stamping, and is coated with firstly nickel (Ni) plating as base plating and subsequently gold (Au) plating as finish plating. 
     As shown in the drawings, each of the eight first contacts  40 F and the seven-second contacts  40 R is in the shape of a letter H in side view and provided with a first arm (lower arm)  41 , a second arm (upper arm)  42  and a resilient connecting portion  43 . The first arm  41  and the second arm  42  are substantially parallel to each other with a predetermined distance therebetween, and the resilient connecting portion  43  connects middle portions of the first arm  41  and the second arm  42  to each other. The first arm  41  and the second arm  42  are provided at the front ends thereof with a contacting projection  44  and a contacting projection  45 , respectively, which project toward each other to face each other. The first arm  41  is provided, on the bottom surface thereof in the vicinity of the rear end of the first arm  41 , with a hook-shaped engaging portion  46 . 
     Each first contact  40 F is provided, on the left surface thereof, at an approximate center of this left surface, with a locking protrusion  47  which protrudes leftward, and each second contact  40 R is provided, on the left surface thereof at an approximate center of this left surface, with a locking protrusion  48  which protrudes leftward. The locking protrusions  47  and  48  are respectively formed on the first and second contacts  40 F and  40 R by indenting the right side surfaces of the of first and second contacts  40 F and  40 R in the leftward direction. As shown in  FIGS. 5 and 9 , the locking protrusion  47  of each first contact  40 F is provided with a front inclined surface  49 F and a rear inclined surface  49 R positioned behind the front inclined surface  49 F. Likewise, as shown in  FIG. 10 , the locking protrusion  48  of each second contact  40 R is provided with a front inclined surface  49 F and a rear inclined surface  49 R positioned behind the front inclined surface  49 F. As shown in  FIG. 5 , the locking protrusions  47  on the eight first contacts  40 F are positioned closer to the front of the insulator  10  than the locking protrusions  48  on the seven-second contacts  40 R in the forward/rearward direction. 
     The eight first contacts  40 F are inserted into the eight first contact support grooves  26 F from the rear, respectively, while the seven second contacts  40 R are inserted into the seven second contact support grooves  26 R from the rear, respectively. 
     As shown in  FIG. 7 , upon each first contact  40 F being inserted into the associated contact support groove  26 F, the bottom surface of the first arm  41  comes in contact with the bottom of the associated first contact support groove  26 F (the bottom of the associated recessed groove formed on the bottom plate portion  22 ), the top surface of the second arm  42  is a certain distance apart downwardly from the top surface of the associated first contact support groove  26 F (the top surface of the associated recessed groove formed on the top plate portion  23 ), and the locking protrusion  47  of the first contact  40 F is engaged in the associated locking hole  27 . Thereupon, the rear inclined surface  49 R of the locking protrusion  47  comes in contact with a rear edge of the associated locking hole  27 , while the hook-shaped engaging portion  46  of the first contact  40 F is engaged in the associated locking recess  29  of the insulator  20  (see  FIGS. 3 and 7  through  9 ), and accordingly, each first contact  40 F inserted into the associated first contact support groove  26 F becomes securely fitted therein in the forward/rearward direction. Additionally, the rear inclined surface  49 R of the locking protrusion  47  of each first contact  40 F comes in contact with a rear edge of the associated locking hole  27  as noted above while the right side surface of the first contact  40 F comes in contact with the support flat surface  25  of the associated partition wall  24  as shown in  FIG. 5 , and accordingly, each first contact  40 F inserted into the associated first contact support groove  26 F becomes securely fitted therein in the leftward/rightward direction either. Additionally, the bottom surface of each first arm  41  comes in contact with the bottom of the associated first contact support groove  26 F as noted above while the top surface of the locking protrusion  47  comes in contact with the top surface of the associated locking hole  27  (see  FIG. 6 ), and accordingly, each first contact  40 F inserted into the associated first contact support groove  26 F becomes securely fitted therein in the upward/downward direction either. 
     Likewise, as shown in  FIGS. 8 and 9 , upon each second contact  40 R being inserted into the associated contact support groove  26 R, the bottom surface of the first arm  41  comes in contact with the bottom of the associated second contact support groove  26 R (the bottom of the associated recessed groove formed on the bottom plate portion  22 ), and the top surface of the second arm  42  is a certain distance apart downwardly from the top surface of the associated first contact support groove  26 R (the top surface of the associated recessed groove formed on the top plate portion  23 ). Thereupon, the locking protrusion  48  of the second contact  40 R is engaged in the associated locking hole  28 , and thereafter, the rear inclined surface  49 R of the locking protrusion  48  comes in contact with a rear edge of the associated locking hole  28  while the hook-shaped engaging portion  46  of the second contact  40 R is engaged in the associated locking recess  29 . Additionally, the right side surface of the second contact  40 R comes in contact with the support flat surface  25  of the associated partition wall  24 , the bottom surface of each first arm  41  of the second contact  40 R comes in contact with the bottom of the associated second contact support groove  26 R, and the top surface of the locking protrusion  48  of the second contact  40 R comes in contact with the top surface of the associated locking hole  28 . Accordingly, each second contact  40 R inserted into the associated second contact support groove  26 R becomes securely fitted therein in each of the forward/rearward direction, the leftward/rightward direction and the upward/downward direction. 
     As shown in  FIG. 5 , the front portions of the first and second contacts  40 F and  40 R are not in contact with either a front portion of the adjacent left side surface which is positioned in front of the support surface  25  or a front portion of the adjacent right side surface of the associated left and right partition walls  24  in the associated first and second contact support grooves  26 F and  26 R, respectively. Due to this structure, the first and second arms  41  and  42  of each first contact  40 F and the first and second arms  41  and  42  of each second contact  40 R can be resiliently deformed inside the associated first contact support groove  26 F and the associated second contact support groove  26 R, respectively. 
     The rotational actuator  50  is a plate member extending in the leftward/rightward direction and molded out of a heat-resistant synthetic resin by injection molding. The rotational actuator  50  is provided with a total of fifteen through-holes  51  which are arranged at regular intervals in the leftward/rightward direction and each of which is formed through the rotational actuator  50  in the forward/rearward direction. The rotational actuator  50  is provided immediately below the fifteen through-holes  51  with fifteen cam portions  52 , respectively, each of which is approximately rectangular in cross sectional shape. Additionally, the rotational actuator  50  is provided, at each of the left and right side surfaces thereof close to each end of the rotational actuator  50  with a pair of (left and right) pivots  53  which project in opposite directions away from each other in the leftward/rightward direction to be substantially coaxial with the fifteen cam portions  52 . 
     The rotational actuator  50  that has the above described structure is pivoted on the insulator  20  to be rotatable about the left and right pivots  53  with the left and right pivots  53  being engaged into the left and right bearing recesses  30  formed in the left and right side wall portions  21  of the insulator  20 , respectively (see  FIGS. 5 and 6 ), and with the rear ends of the second arms  42  of the eight first contacts  40 F and the seven second contacts  40 R being inserted into the fifteen through-holes  51 , respectively. The rotational actuator  50  is rotatable between an unlocked position shown in  FIGS. 7 and 8 , in which the rotational actuator  50  stands substantially vertical, and a locked position shown in  FIG. 9 , in which the rotational actuator  50  lies substantially horizontal. 
     In order to mount the connector  10  that has the above described structure onto a top surface of a circuit board CB (see  FIGS. 7 through 9 ), firstly solder paste is applied between the rear ends (tail portions) of the first arms  41  of each first contact  40 F and each second contact  40 R and a circuit pattern (not shown) formed on the top surface of the circuit board CB, and soldering paste is applied between the tail portions  36  of the left and right anchors  35  and a ground pattern (not shown) formed on the top surface of the circuit board CB, and subsequently, each solder paste is melted by heat in a reflow furnace. Thereupon, the rear ends of the first arms  41  of each first contact  40 F and each second contact  40 R are soldered to the aforementioned circuit pattern while the left and right tail portions  36  are soldered to the aforementioned ground pattern, which completes the mounting of the connector  10  to the circuit board CB. 
     Thereafter, as shown in  FIGS. 7 through 9 , upon an end of an FPC (object to be connected to each first contact  40 F and each second contact  40 R)  60  being inserted in between the bottom plate portion  22  and the top plate portion  23  from the front of the insulator  20  of the connector  10  that has been fixed integrally with the circuit board CB, a rear portion of the FPC  60  is positioned between the front portion of the first arm  41  and the second portion of the second arm  42  of each first contact  40 F and of each second contact  40 R, and simultaneously positioned in the insertion recess  24   a  of each partition wall  24 . 
     Rotating the rotational actuator  50  to the locked position shown in  FIG. 9  causes each cam portion  52  to press the bottom rear surface of the associated second arm  42  upwardly, thus causing the resilient connecting portions  43  of each first contact  40 F and each second contact  40 R to be resiliently deformed so that the second arms  42  of each first contact  40 F and each second contact  40 R rotate counterclockwise about the resilient connecting portions  43 . Consequently, each contacting projection  45  comes in contact with a circuit pattern formed on the upper surface of the FPC  60 , and furthermore, the contacting pressure of each contacting projection  44  against a circuit pattern formed on the lower surface of the FPC  60  increases, and accordingly, each first contact  40 F and each second contact  40 R are reliably electrically connected to the FPC  60 . 
     As described above, according to the above illustrated embodiment of the connector, since the locking protrusion  47  of each first contact  40 F and the locking protrusion  48  of each second contact  40 R are engaged in the associated locking hole  27  and the associated locking hole  28  upon each first contact  40 F and each second contact  40 R being inserted into the associated contact support groove  26 F and the associated contact support groove  26 R, respectively, each first contact  40 F and each second contact  40 R are firmly prevented from coming off the associated first contact support groove  26 F and the associated second contact support groove  26 R, respectively. 
     Moreover, there is no possibility of the insulator  20  becoming warped by an assembling operation for the connector  10  even if the locking protrusion  47  of each first contact  40 F and the locking protrusion  48  of each second contact  40 R are engaged in the associated locking hole  27  and the associated locking hole  28 , respectively, since no stress is applied to each partition wall  24  by either each locking protrusion  47  or each locking protrusion  48 . Furthermore, even if reflow heat is transmitted to the insulator  20  when reflow soldering is performed, warping or the like which may be caused by residual stress does not occur. Accordingly, the connector  10  can be easily mounted onto the circuit board CB and neither the holding force for holding each first contact  40 F by the associated locking hole  27  nor the holding force for holding each second contact  40 R by the associated locking hole  28  deteriorates. 
     If the eight locking holes  27  and the seven locking holes  28  are formed on top surfaces of the fifteen recessed grooves formed on a bottom surface (inner surface) of the top plate portion  23 , respectively, and if the locking protrusions  47  of the eight first contacts  40 F and the seven locking protrusions  48  of the seven second contacts  40 R that are respectively engaged in the eight locking holes  27  and the seven locking holes  28  are formed on top surfaces of the second arms  42  of the eight first contacts  40 F and top surfaces of the second arms  42  of the seven second contacts  40 R, respectively, the second arm  42  of neither each first contact  40 F nor each second contact  40 R can rotate even if the rotational actuator  50  is operated. However, in the case where each first contact  40 F is provided on a lateral side of the first arm  41  thereof with a locking protrusion  47  while each second contact  40 R is provided on a lateral side of the first arm  41  thereof with a locking protrusion  48  as disclosed in the above described embodiment of the connector  10 , the second arm  42  is not prevented from rotating. 
     As shown in  FIG. 5 , the locking protrusions  47  (the locking holes  27 ) of the eight first contacts  40 F and the locking protrusions  48  (the locking holes  28 ) of the seven second contacts  40 R are provided at mutually different positions in the forward/rearward direction (to be arranged in a zigzag fashion), and accordingly, loads can be prevented from being exerted on the fifteen partition walls  24  at the same positions thereon in the lengthwise direction thereof, respectively, when the eight first contacts  40 F and the seven second contacts  40 R are installed to the insulator  20 . In addition, if only the eight first contacts  40 F, the locking holes  27  (engaging objects) of which are positioned closer to the front of the insulator  20  than the locking holes  28  of the seven second contacts  40 R in the contact insertion direction (which corresponds to the forward/rearward direction), are firstly installed into the insulator  20  and subsequently the seven second contacts  40 R, the locking holes  28  (engaging objects) of which are positioned closer to the rear of the insulator  20  than the locking holes  27  of the eight first contacts  40 F in the contact insertion direction, are installed into the insulator  20 , loads exerted on the insulator  20  when the eight first contacts  40 F and the seven second contacts  40 R are installed to the insulator  20  can further be reduced. Additionally, if thin-walled portions (portions in which the locking holes  27  and  28  are formed) are formed on the fifteen partition walls  24  at the same positions thereon in the lengthwise direction thereof, such portions of the insulator  20  substantially decrease in strength, and the flowability (moldability) of synthetic resin of the insulator  20  deteriorates when the insulator is molded by injection molding. However, in the above-described embodiment of the connector, this kind of problem does not occur since the positions of such thin-walled portions of the fifteen partition walls  24  in the lengthwise direction are separated into two different positions in the same lengthwise direction as clearly shown in  FIG. 5 . 
     Although the present invention has been described based on the above-illustrated embodiment of the connector, the present invention is not limited solely to this particular embodiment; making various modifications to the above-illustrated embodiment of the connector is possible. 
     For instance, a modified embodiment of the connector shown in  FIG. 11  is also possible. The connector  10 ′ is provided with an insulator  20 ′, a plurality of contacts  70 , a rotational actuator  50 ′ and a pair of anchors  80 . The pair of anchors  80  are fixed to left and right ends of an internal space within the insulator  20 ′, respectively. 
     The insulator  20 ′ is provided with a pair of (left and right) side wall portions  21 ′, a bottom plate portion  22 ′, a top plate portion  23 ′ and a plurality of partition walls  24 ′. The plurality of contacts  70  are inserted into a corresponding plurality of contact support grooves  26 ′ which are formed as separate spaces between the plurality of partition walls  24 ′, respectively. The rotational actuator  50 ′ is provided with a plurality of through-holes  51 ′, a plurality of cam portions  52 ′, a pair of pivots and a plurality of rotational engaging portions  54 . The plurality of cam portions  52 ′ are formed at the lower end (base end) of the rotational actuator  50 ′ and are identical in number to the through-holes  51 ′. The plurality of rotational engaging portions  54  are identical in number to the plurality of through-holes  51 ′ and formed at positions corresponding to the positions of the cam portions  52  of the rotational actuator  50 . 
     As shown in  FIG. 11 , each contact  70  is provided with a base portion  71 , a first arm  72  and a second arm  73 . The first arm  72  and the second arm  73  extend forward from the base portion  71 . The first arm  72  of each contact  70  is provided at the front end thereof with a contacting projection  74  which projects upward, and the second arm  73  of each contact  70  is provided, on a bottom surface thereof in the vicinity of a front end of the second arm  73 , with an engaging recess  75 . The aforementioned pair of (left and right) pivots (not shown) of the rotational actuator  50 ′ are positioned on a support surface  81  formed on the rear top surfaces of the pair of anchors  80  to be supported thereby, respectively, and the second arm  73  of each contact  70  passes through the associated through-hole  51 ′ of the rotational actuator  50 ′ so that the associated rotational engaging portion  54  engages with the engaging recess  75  of second arm  73 . 
     If the FPC  60  is inserted into the connector  10 ′ when the rotational actuator  50 ′ is in an unlocked position shown in  FIG. 11 , in which the rotational actuator  50 ′ stands substantially vertical, a circuit pattern formed on a lower surface of the FPC  60  comes in contact with the contacting projection  74  of the first arm  72  of each contact  70 . Thereafter, rotating the rotational actuator  50 ′ forward to the locked position (not shown), in which the rotational actuator  50 ′ lies substantially horizontal, causes each cam portion  52 ′ that is formed on the lower end (base end) of the rotating actuator  50 ′ to be pressed against an upper surface of the FPC  60 , thus causing the contacting pressure of the contacting projection  74  of each first arm  72  against the aforementioned circuit pattern on the lower surface of the FPC  60  to increase, and accordingly, the first arm  72  of each contact  70  is reliably electrically connected to the FPC  60 . 
     The top plate portion  23  of the connector  10  is provided, on a lower surface thereof in the vicinity of the rear end of the top plate portion  23 , with a plurality of locking holes (holding portions)  27 ′ formed as bottomed holes which are arranged at regular intervals in the leftward/rightward direction (wherein the plurality of locking holes  27 ′ are provided at alternately different positions in the forward/rearward direction to be arranged in a zigzag fashion). In addition, the base portions  71  of the plurality of contacts  70  are provided on top surfaces thereof with a plurality of engaging projections  76  which are engaged with the plurality of locking holes  27 ′, respectively (the plurality of engaging projections  76  of the plurality of contacts  70  are provided at alternately different positions in the forward/rearward direction to correspond to the positions of the plurality of locking holes  27 ′, respectively). 
     As shown in  FIG. 11 , in the modified embodiment of the connector  10 ′, the locking protrusion  76  of each contact  70  is provided at the rear end thereof with a rear inclined surface, and this rear inclined surface is in contact with a rear edge of the associated locking hole  27 ′, while the front of a tail portion  77  (portion to be soldered to a circuit pattern formed on an upper surface of the circuit board CB) which projects from the rear end of the bottom surface of each contact  70  is in contact with the rear end surface of the bottom plate portion  22 ′ of the insulator  20 ′, and accordingly, each contact  70  inserted into the associated contact support groove  26 ′ becomes securely fitted therein in the forward/rearward direction relative to the insulator  20 ′. 
     It is possible for the locking protrusion  76  of each contact  70  to be formed on a bottom surface thereof, for the plurality of locking holes  27 ′ to be formed on the bottom plate portion  22 ′, and for the top surface of each contact  70  to be brought into contact with a lower surface (inner surface) of the top plate portion  23 ′. 
     As shown in  FIGS. 12 and 13 , the rear end surface of a locking protrusion  91  provided on a first contact  90 F can be formed as a flat surface orthogonal to the lengthwise direction of the first contact  90 F, rather than being formed as an inclined surface. In this case, upon the first contact  90 F being inserted into the associated first contact support groove  26 F, the rear end surface (flat surface) of the locking protrusion  91  comes in contact with the rear surface of the associated locking hole  27 . 
     As shown in  FIGS. 14 and 15 , a locking projection  96  provided on a first contact  95 F can be formed into a cut-and-raised portion so as to be resiliently deformable. In this case, in an assembling process (process of inserting the first contact  95 F into the associated first contact support groove  26 F), the locking projection  96  is resiliently deformed by coming into contact with a side surface of the associated first contact support groove  26 F, and upon the first contact  95 F being inserted into the associated first contact support groove  26 F to a predetermined position, the locking projection  96  snaps into the associated locking hole  27  by resiliently returning to the original shape. 
     The modified embodiments shown in  FIGS. 12 through 15  are also applicable to each second contact. 
     As shown in  FIGS. 16 and 17 , a connector  10 ″ having a structure such that each first contact  40 F″ is installed into an insulator  20 ″ from front, is also possible. 
     A bottom plate portion  22 ″ of the insulator  20 ″ is provided, on portions of a front edge of the bottom plate portion  22 ″ which face the plurality of first contacts  40 F″, with a plurality of locking recesses  29 ″, respectively, and is further provided with a corresponding plurality of engaging recesses  22 A. 
     Each first contact  40 F″ is provided with a first arm  41 ″, a second arm  42  and a resilient connecting portion  43 . The first arm  41 ″ is provided, on the bottom surface thereof in the vicinity of the front end of the first arm  41 ″, with a hook-shaped engaging portion  46 ″ which is engaged with an associated locking recess  29 ″, and is provided at the rear end of the first arm  41 ″ with an engaging projection  41 A which is engaged in an associated engaging recess  22 A. 
     The structure of the remainder of the connector  10 ″ is identical to the structure of the connector  10 , so that each second contact  40 R is inserted into the insulator  20 ″ from rear in a similar manner to the connector  10 . 
     As shown in  FIG. 17 , a locking protrusion  47 ″ which protrudes from the left side surface of each first contact  40 F″ is provided with a front inclined surface  49 F″ and a rear inclined surface  49 R″, and the front inclined surface  49 F″ is in contact with a front edge (left edge with respect to  FIG. 17 ) of the associated locking hole  27 ″. In addition, although not shown in the drawings, the top surface of the locking protrusion  47 ″ of each first contact  40 F″ is in contact with the top surface of the associated locking hole  27 ″. 
     In addition, as shown in  FIG. 18 , each first contact  40 F″ can be provided with a locking protrusion  47 ′″ instead of the locking protrusion  47 ″. The locking protrusion  47 ′″ is provided with a front inclined surface  49 F′″ and a rear inclined surface  49 R′″ which are in contact with a front edge and a rear edge of the associated locking hole  27 ″, respectively. Additionally, although not shown in the drawings, the top surface of the locking protrusion  47 ′″ of each first contact  40 F″ is in contact with the top surface of the associated locking hole  27 ″. 
     The locking protrusion  47 ′″ of each first contact  40 F″ is also applicable to each first contact  40 F and each second contact  40 R. 
     Although the locking protrusion ( 47 ,  48 ,  47 ″ or  47 ′″) of each contact is brought into contact with the associated locking hole ( 27 ,  28  or  27 ″) in each of the above-illustrated embodiments and modified embodiments, it is possible to make the locking protrusion and the associated locking hole face each other with a slight clearance therebetween. In addition, this is also true with regard to the relationship between the locking protrusion ( 47 ,  48 ,  47 ″ or  47 ′″) of each contact and the top surface of the associated locking hole ( 27 ,  28  or  27 ″). 
     The locking protrusion  47  of each first contact  40 F and the locking protrusion  48  of each second contact  40 R can be formed to be identical in cross sectional shape to the associated locking holes  27  and  28 , respectively, so that front, rear, upper and lower surfaces of the locking protrusion  47  respectively come into contact with front, rear, upper and lower surfaces in the associated locking hole  27  while front, rear, upper and lower surfaces of the locking protrusion  48  respectively come into contact with front, rear, upper and lower surfaces in the associated locking hole  28  when each first contact  40 F and each second contact  40 R are inserted into the associated first contact support groove  26 F and the associated second contact support groove  26 R, respectively. According to this structure, the holding force for holding each first contact  40 F by the associated locking hole  27  and the holding force for holding each second contact  40 R by the associated locking hole  28  are improved. Similarly, the locking protrusion  76  of each contact  70  in the modified embodiment shown in  FIG. 11  can be formed to be identical in cross sectional shape to the associated locking hole  27 ′ so that front, rear, upper and lower surfaces of the locking protrusion  76  respectively come into contact with front, rear, upper and lower surfaces in the associated locking hole  27 ′. 
     If no burden upon the insulator  20  needs to be taken into consideration, all the locking holes  27  and  28  can be formed on the insulator  20  and all the locking protrusions  47  and  48  can be formed on the first and second contacts at the same positions in the forward/rearward direction. Likewise, all the locking holes  27 ′ can be formed on the insulator  20 ′ and the locking protrusions  76  can be formed on the contacts  70  at the same positions in the forward/rearward direction in the modified embodiment of the connector of  FIG. 11 . 
     In addition, each locking hole  27  and  28  can also be formed as a through-hole which extends through the associated partition wall  24  in the leftward/rightward direction, and each locking hole  27 ′ can also be formed as a through-hole which extends through the associated locking hole  27 ′ and the top plate portion  23 ′ in the upward/downward direction. 
     In addition, the basic structure of the connector according to the present invention is not limited solely to the above-described embodiments and modified embodiments. For instance, the present invention can also be applied to a connector equipped with a sliding-type actuator. 
     Additionally, an object to be connected to each contact of the connector can also be a cable other than an FPC, e.g., a flexible flat cable (FFC). 
     Obvious changes may be made in the specific embodiments of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention.