Plug-type connector and electric connector comprising the same

A plug-type connector for connecting end portions of a pair of FFCs extending in parallel to each other. The connecter is provided with: a holder having a placing frame provided on the surface and backside thereof with a pair of placing faces on which the end portions of the pair of FFCs are respectively placed; and a fixing member capable of fixing the end portions of the FFCs to the corresponding placing faces of the holder. The fixing member includes: an annular portion which defines an insertion hole into which the placing frame of the holder with the end portions of the FFCs placed on the corresponding placing faces, can be inserted together with the FFCs; and engagement portions which are engageable with corresponding engaged portions of the holder when the annular portion is brought toward the holder with the pair of FFCs previously inserted into the insertion hole of the annular portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plug-type connector for connecting an FFC (Flexible Flat Cable), and an electric connector comprising such a plug-type connector.

2. Description of Related Art

Conventionally, an FPC (Flexible Printed Circuit) in the form of a flexible printed circuit board is connected to a base board by connecting a plug-type connector connected to an end of the FPC, to a receptacle-type base connector fixed to the base board.

For example, in a plug-type connector disclosed in Japanese Unexamined Patent Publication No. 11-329619 (1999), a plug housing is formed by a pair of mutually divided sandwiching members, which are connected to each other with an end of an FPC held by and between these sandwiching members. A fixing pin at one sandwiching member passes through a through-hole formed in the FPC at its widthwise intermediate position. This fixing pin is fitted to the other sandwiching member such that the FPC is securely held in the plug housing.

Generally, an FFC is smaller in the degree of freedom as to the conductor layout as compared with an FPC. Accordingly, it is difficult to form, in the FFC at its widthwise intermediate position, a through-hole or the like for a fixing pin as mentioned above. That is, the plug-type connector disclosed in the above-mentioned Publication can hardly be applied to FFC connection.

If the plug-type connector disclosed in the above-mentioned Publication is applied to FFC connection with no fixing pin used, this involves the likelihood that the FFC is unstably held due to variations of dimensional precision and combination precision of the sandwiching members, and the like.

On the other hand, there is desired a connector capable of collectively connecting a plurality of FFCs.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a plug-type connector which is capable of readily connecting and securely holding a plurality of FFCs, and also to provide an electric connector comprising such a plug-type connector.

The present invention provides a plug-type connector for connecting end portions of a pair of FFCs extending in parallel to each other. This plug-type connector comprises: a holder comprising a placing frame provided on the surface and backside thereof with a pair of placing faces on which end portions of a pair of FFCs are respectively placed; and a fixing member capable of fixing the end portions of the FFCs to the corresponding placing faces of the holder. The fixing member comprises: an annular portion which defines an insertion hole into which the placing frame of the holder with the end portions of the FFCs placed on the corresponding placing faces, can be inserted together with the FFCs; and engagement portions which are engageable with corresponding engaged portions of the holder when the annular portion is brought toward the holder with the FFCs previously inserted into the insertion hole of the annular portion.

According to the present invention having the arrangement above-mentioned, with the FFC end portions temporarily held by the corresponding placing faces of the placing frame of the holder, the FFC end portions and the placing frame are fitted into the annular portion of the fixing member such that the engagement portions of the fixing member engage with the engaged portions of the holder. Thus, the pair of FFCs can readily be connected to the plug-type connector. When an FFC is held by and between two sandwiching members connected to each other as conventionally done, this involves the likelihood that the FFC is unstably held due to variations of dimensional precision and combination precision of the sandwiching members. On the other hand, the present invention uses the fixing member having the annular portion, thus enabling the FFCs to be stably held.

The placing frame of the holder may comprise: first and second placing plates respectively provided on the mutually reverse sides thereof with placing faces; and connecting portions for connecting the first and second placing plates to each other. In this case, the fixing member preferably comprises: first and second frames for holding the ends of the corresponding FFCs in cooperation with the corresponding placing faces; and a pair of lateral frames for connecting the corresponding ends of the first and second frames to each other, the lateral frames and the first and second frames defining the annular portion. According to the arrangement above-mentioned, the pair of placing plates are connected to each other by the connecting portions to form the placing frame. This enables the holder to be improved in strength. Further, the fixing member is made in the form of a box structure using the first and second frames and the pair of lateral frames. This enables the fixing member to be improved in strength. Thus, the plug-type connector can be improved in strength in its entirety.

The first and second placing plates may be different from each other in width, and the first and second frames may also be different from each other in width. This arrangement prevents the placing frame of the holder from being inversely inserted into the annular portion of the fixing member.

Further, a concave may be formed between the rear end portions of the first and second placing plates of the holder, and the fixing member may comprise an intermediate frame which connects the pair of lateral frames to each other, which extends in parallel to the first and second frames, and which is engageable with the concave. According to the arrangement above-mentioned, the intermediate frame of the fixing member is fitted into the concave between the placing plates of the holder, and the first and second placing plates are fitted into the annular portion at both sides of the intermediate frame. This enables the holder and the fixing member to be joined to each other without any backlash or looseness.

A reinforcing sheet may be attached to the backside of the end portion of each of the FFCs for holding exposed conductors in a row. In this case, a pulling-out preventing projection is preferably formed on each of the placing faces of the holder, this pulling-out preventing projection being engageable with an edge portion of the reinforcing sheet of each of the FFCs. According to the arrangement above-mentioned, before the fixing member is mounted, the FFCs can be temporarily held with their end portions placed on the placing faces of the holder. This improves the working efficiency of connecting the FFCs to the plug-type connector. Further, such improvement can be achieved by a simple structure utilizing the reinforcing sheets of the FFCs. Further, provision is made such that the FFCs are prevented from being pulled out after assembled. The pulling-out preventing projections fulfill their function as far as they can engage with the thin reinforcing sheets. Accordingly, the projecting amount may be small. Thus, the plug-type connector can be made low in height.

The holder may comprise, on each of the placing faces, a pair of holding frames for defining grooves into which a pair of lateral edges of each of the end portions of the corresponding FFCs, are introduced. In this case, the plug-type connector of the present invention is preferably arranged such that the fixing member comprises a pair of projection portions which project from each of the first and second frames to come in contact with the corresponding holding frames of the holder, that the engagement portions are formed on the projection portions, and that the corresponding holding frames and the projection portions are combined with each other, thus forming a part of an insertion projecting portion to be inserted into an insertion concave of a counter-connector.

According to the arrangement above-mentioned, the holding frames of the holder and the projection portions of the fixing member, form a part of the insertion projecting portion, which is inserted into the insertion concave of a counter-connector. This assures a secure connector connection. Further, the holding frames and the projection portions not only serve as the insertion projecting portion, but are also utilized for defining the grooves and forming the engagement portions. Thus, the holding frames and the projection portions can fulfill a plurality of functions even though they have a simple structure.

An electric connector of the present invention comprises: a plug-type connector having the features above-mentioned; and a receptacle-type connector combined with the plug-type connector. The receptacle-type connector comprises: a housing defining an insertion concave into which the insertion projecting portion of the plug-type connector is inserted; and a plurality of contacts arranged side by side in the insertion concave. The present invention can provide an electric connector ideal for connection of a pair of FFCs to a board when used with the receptacle-type connector attached to the board.

These and other features, objects and advantages of the present invention will be more fully apparent from the following detailed description set forth below when taken in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFFERED EMBODIMENTS

FIG. 1is an exploded perspective view of (i) a plug-type connector2, according to an embodiment of the present invention, to which a pair of FFCs1,100are connected, and (ii) a base connector3serving as a receptacle-type connector.FIG. 2is an exploded perspective view of the FFCs1,100and the plug-type connector2, andFIG. 3is a section view of the FFC1.

Referring toFIGS. 2 and 3, the FFC1comprises a number of conductors4arranged side by side, and insulating films5laminated on the both sides of the conductors4. A synthetic resin reinforcing sheet6is attached to the backside1bof an end portion1aof the FFC1. The reinforcing sheet6aligns and holds exposed conductors4aextending from the end portion1aof the FFC1. Referring toFIG. 2, the reinforcing sheet6is provided in a pair of lateral edges6a,6bthereof with first and second concaved grooves6c,6d. Each of the concaved grooves6c,6dis substantially rectangular for example. Provision is made such that the widths L1, L2of the first and second concaved grooves6c,6dare different from each other with respect to the longitudinal direction of the FFC1.

The FFC100has an arrangement similar to that of the FFC1. The FFCs1,100are disposed with their backsides being opposite to each other. The FFC100has a width smaller by a predetermined distance W than the width of the FFC1. More specifically, the number of the conductors4of the FFC100is smaller than that of the conductors4of the FFC1.

Referring toFIGS. 1 and 5, the base connector3comprises: a base housing8which defines an insertion concave7, which is made of an insulating synthetic resin, and which is to be attached to the surface Ka of a board K; and two contact rows9,90each having contacts9a,9bwhich pass through the base housing8and which are alternately disposed side by side.

Referring toFIGS. 1 and 4, the base housing8has first and second walls10,11opposite to each other, and a pair of lateral walls12,13which connect the opposite ends of the first and second walls10,11to each other. These walls10to13define the insertion concave7. For convenience's sake, the side of the base connector3at which the first wall10is disposed, is referred to as the front side X.

The lateral walls12,13have first portions12a,13abetween which the distance is relatively wide, and second portions12b,13bbetween which the distance is relatively narrow. The lateral walls12,13further have step portions12c,13cbetween the first portions12a,13aand the second portions12b,13b.

Referring toFIG. 4, the insertion concave7has a first concave7aalong the second wall11, and a pair of second concaves7band a pair of third concaves7cwhich communicate with both ends of the first concave7a. The pair of second concaves7bare formed at both sides of the contact row9and extend along the first portions12a,13aof the lateral walls12,13. The pair of third concaves7care formed at both sides of the contact row90and extend along the second portions12b,13bof the lateral walls12,13.

Referring toFIGS. 4 and 5, a plurality of partition walls14in the form of a rib of comb teeth are disposed side by side at each of the first and second walls10,11defining the insertion concave7. The partition walls14extend into the first concave7aof the insertion concave7. Contact holding grooves15which hold corresponding contacts9a,9bof the corresponding contact rows9,90, are formed between adjacent partition walls14. The contact holding grooves15are opened in the first concave7aof the insertion concave7. The contacts9a,9bof the contact row9are so disposed as to be opposite to the contacts9a,9bof the contact row90in the back and forth direction of the base housing8.

Referring toFIG. 5, contact holding holes16which hold corresponding contacts9a,9bof the corresponding contact rows9,90, are formed in the bottom8aof the base housing8at the lower part of the insertion concave7. The contact holding holes16communicate with the corresponding contact holding grooves15.

Each contact9ahas a long main body17housed in a contact holding groove15, and a projecting portion18turned down from the tip of the main body17and curved in the form of a mountain. The top of the projecting portion18forms a contact portion19entering inside of the first concave7aof the insertion concave7. Further, each contact9acomprises: a press-fitting portion20which extends from the main body17and which is pressed in a contact holding hole16; and a lead21awhich extends from the press-fitting portion20and which downwardly projects from the base housing8.

The alternately disposed contacts9a,9bhave leads21a,21bdifferent from each other only in shape. Each lead21ais made in the form of a hook, while each lead21bextends substantially straight from the press-fitting portion20. Accordingly, the leads21a,21bare disposed in a zigzag manner with their positions alternately shifted back and forth. The leads21a,21bpass through the board K and are soldered on the backside Kb thereof.

Referring toFIGS. 1 and 2, the plug-type connector2has a holder22for holding the end portions1aof a pair of FFCs1,100and a fixing member23for fixing the pair of FFCs1,100to the holder22.

Referring toFIGS. 2,6(a),6(b),6(c),7and12, the holder22comprises: a placing frame61formed by connecting mutually parallel first and second placing plates25,250by connecting portions60; a pair of placing faces24,240formed on the placing plates25,250at their mutually reverse sides; and a pair of holding frames26,27respectively disposed on each of the placing faces24,240at their front sides. As shown inFIG. 7, a concave62is formed between the rear end portions of the first and second placing plates25,250.

Referring toFIGS. 2,6(a) and6(c), pulling-out preventing projections28are respectively formed on the placing faces24,240at the rear edge portions24athereof. As shown in FIGS.3and5, the pulling-out preventing projections28are respectively engaged with rear edge portions6eof the reinforcing sheets6of the FFCs1,100placed on the placing faces24,240, thus preventing the FFCs1,100from being pulled out.

As each pulling-out preventing projection28, a single long pulling-out preventing projection may be disposed on each of the placing faces24,240as shown inFIGS. 6(a) and6(c), or a plurality of pulling-out preventing projections may be disposed at regular intervals. Each pulling-out preventing projection28fulfills its function as far as it can engage with the reinforcing sheet6. Accordingly, the projecting amount may be very small (for example, about 0.2 mm).

Each of the placing faces24,240is provided at both lateral sides thereof with positioning projections30,31engageable with the concaved grooves6c,6d(SeeFIG. 2) of each of the FFCs1,100. The positioning projections30,31have such proper widths as to be just fitted into the concaved grooves6c,6d, respectively. This prevents the wrong sides of the FFCs1,100from being respectively placed on the placing faces24,240.

Referring toFIGS. 6(a),6(b),6(c) and12, the pair of holding frames26,27disposed on each of the placing faces24,240, have lateral frames51standing from the lateral edges of each of the placing plates25,250, and upper frames52inwardly extending from the upper front portions of the lateral frames51. As shown inFIG. 6(b), the upper frames52, the lateral frames51and the corresponding placing plates25,250, define grooves32into which the corresponding lateral edges of the end portions1aof the FFCs1,100can be introduced.

Referring toFIGS. 6(a),6(b),6(c) and7, projections33are formed at the upper rear portions of the lateral frames51. The projections33comprise engaged portions34with which hooks serving as engagement portions of the fixing member23to be discussed later, are engaged.

Referring toFIGS. 2,9(a),9(b),10,11and12, the fixing member23has an annular portion37. As shown inFIG. 8, this annular portion37defines a substantially rectangular insertion hole38into which the placing frame61of the holder22with the end portions1aof the FFCs1,100placed thereon, is inserted together with the FFCs1,100.

Referring toFIGS. 9(a) and9(b), the annular portion37comprises: first and second frames39,40respectively corresponding to the placing faces24,240of the first and second placing plates25,250of the holder22; and a pair of lateral frames41,42for connecting the opposite ends of the first and second frames39,40to each other. These frames39to42define the insertion hole38. The lateral frames41,42have first portions41a,42abetween which the distance is relatively wide, and second portions41b,42bbetween which the distance is relatively narrow. The lateral frames41,42further comprise step portions41c,42cbetween the first portions41a,42aand the second portions41b,42b.

The fixing member23has an intermediate frame63which is connected to the lateral frames41,42and which extends in parallel to the first and second frames39,40. The intermediate frame63divides the insertion hole38into first and second insertion holes38a,38binto which the first and second placing plates25,250are respectively inserted.

Two pairs of engagement portions43comprise hooks engageable with the engaged portions34of two pairs of projections33of the holder22, and project from a connection-side end face37aof the annular portion37. As shown inFIGS. 10 and 11which is a section view taken along the line XI—XI inFIG. 9(a), cantilevered resilient pieces44are formed inside of the first and second walls39,40, and the engagement portions43comprising hooks are formed at the ends of those projection portions44aof the resilient pieces44which project from the annular portion37.

Referring toFIGS. 9(a),9(b) and10—16, in the vicinity of the inner sides of each pair of engagement portions43, a pair of positioning projections45project from the connection-side end face37aof the annular portion37.

Referring toFIGS. 12 and 13, the rear part of the holder22is inserted into the insertion hole38of the annular portion37of the fixing member23, and the engagement portions43of the fixing member23get over the projections33of the holder22and then engage with the engaged portions34. Thus, the fixing member23and the holder22are joined to each other to form a plug-type connector2.

As shown inFIG. 2, when the holder22and the fixing member23properly face each other, the first and second placing plates25,250of the holder22can respectively be inserted into the first and second insertion holes38a,38bof the fixing member23. Accordingly, the holder22and the fixing member23can be joined to each other. On the other hand, when the holder22and the fixing member23do not properly face each other, the first placing plate25cannot be inserted into the narrower second insertion hole38b, thus preventing the holder22and the fixing member23from being joined to each other.

As shown inFIG. 13, the tips of both the engagement portions43and the positioning projections45of the fixing member23, come in contact with the corresponding upper frames52of the holder22to properly position the fixing member23and the holder22.

In the assembly state of the plug-type connector2shown inFIG. 13, that portion of the fixing member23which projects forwardly from the connection-side end face37aof the annular portion37, forms an insertion projecting portion2aof the plug-type connector2. More specifically, the insertion projecting portion2aincludes the front parts of the placing plates25,250of the holder22, the first and second holding frames26,27of the holder22, and the engagement portions43and the positioning projections45of the fixing member23.

This insertion projecting portion2ais to be inserted into the insertion concave7of the base connector3shown inFIGS. 4 and 5. More specifically, out of the insertion projecting portion2a, the front parts of the placing plates25,250of the holder22are inserted into the first concave7a(SeeFIG. 4) of the insertion concave7, and (i) the first and second holding frames26,27of the holder22and (ii) the engagement portions43and the positioning projections45of the fixing member23, are inserted into the corresponding second concaves7band third concaves7c(SeeFIG. 4) of the insertion concave7. Thus, as shown inFIG. 17, an electric connector A is assembled. In the electric connector A, exposed conductors4aof the FFCs1,100connected to the plug-type connector2, are pressed to and contacted with the contact portions19of the corresponding contacts9a,9bof the base connector3, thereby to achieve electric connection.

As to the connection of the FFCs1,100to the plug-type connector2, the FFCs1,100are previously inserted into the corresponding insertion holes38a,38bof the annular portion37of the fixing member23such that the end portions1aof the FFCs1,100are temporarily held by the corresponding placing plates25,250of the holder22as shown inFIG. 8. At this state, the end portions1aof the FFCs1,100and the placing plates25,250are fitted into the annular portion37of the fixing member23, and the engagement portions43of the fixing member23engage with the engaged portions34of the projections33of the holder22as shown inFIG. 16. In this manner, the plug-type connector2can readily be connected to the FFCs1,100as shown inFIG. 1.

When an FFC is held by and between two sandwiching members connected to each other as conventionally done, this involves the likelihood that the FFC is unstably held due to variations of dimensional precision and combination precision of the sandwiching members. On the other hand, the present invention uses the fixing member23having the annular portion37, thus enabling the FFCs1,100to be stably held.

Further, the pair of placing plates25,250are connected to each other by the connecting portions60to form the placing frame61. This enables the holder22to be improved in strength. Further, the fixing member23is made in the form of a box structure using the first and second frames39,40and the pair of lateral frames41,42. This improves the fixing member23in strength. Thus, the plug-type connector2can be improved in strength in its entirety.

In particular, the pair of lateral frames41,42are connected to each other by the intermediate frame63to further improve the fixing member23in strength. In addition, as shown inFIG. 15, when the holder22and the fixing member23are joined to each other, the intermediate frame63of the fixing member23is fitted into the concave62between the placing plates25,250of the holder22, and the placing plates25,250are respectively fitted into the insertion holes38a,38bat both sides of the intermediate frame63. This enables the holder22and the fixing member23to be firmly joined to each other without any backlash or looseness.

Further, the placing plates25,250of the holder22are different from each other in width, and the insertion holes38a,38bare also different from each other in width. This prevents the holder22from being inversely inserted into the annular portion37of the fixing member23. Further, it is not required to pay special attention to prevention of inverse assembling, thus improving the working efficiency.

Further, as shown inFIG. 8, before the fixing member23is mounted, the end portions1aof the FFCs1,100can be temporarily held as placed on the corresponding placing plates25,250of the holder22. This improves the working efficiency of connecting the FFCs1,100to the plug-type connector2. Further, such improvement can be achieved by a simple structure utilizing the reinforcing sheets6of the FFCs1,100. Further, provision is made such that the FFCs1,100are prevented from being pulled out after assembled. The pulling-out preventing projections28fulfill their function as far as they can engage with the thin reinforcing sheets6. Accordingly, the projecting amount may be small. Thus, the plug-type connector2can be made low in height.

Further, the positioning projections30,31on the placing faces24,240of the placing plates25,250of the holder22, are engaged with the concaved grooves6c,6din the FFCs1,100. This improves the precision of positioning the FFCs1,100with respect to the placing plates25,250. This also contributes to prevention of the FFCs1,100from being pulled out. Further, the concaved grooves6c,6dhave different widths L1, L2, respectively, thus preventing the FFCs1,100from being inversely placed on the placing plates25,250.

The present invention should not be limited to the embodiments above-mentioned. For example, one or more positioning projections (not shown) for positioning the front ends of the FFCs1,100, may be disposed along the front edge portions24b(SeeFIGS. 6(a) and6(c)) of the placing faces24,240.

Further, the first and second concaved grooves6c,6dof the reinforcing sheets6of the FFCs1,100may be eliminated, and the positioning projections30,31of the holder22may also be eliminated.

The present invention may be applied to an electric connector of the side type in which the FFCs1,100are inserted transversely along the surface of a printed board, instead of the type in which the FFCs1,100are inserted from above the printed board.

Embodiments of the present invention have been discussed in detail, but these embodiments are mere specific examples for clarifying the technical contents of the present invention. Therefore, the present invention should not be construed as limited to these specific examples. The spirit and scope of the present invention are limited only by the appended claims.

This Application corresponds to Japanese Patent Application No. 2003-164057 filed with the Japanese Patent Office on Jun. 9, 2003, the full disclosure of which is incorporated herein by reference.