ELECTRICAL CONNECTOR FOR CIRCUIT BOARD

Abstract: The present invention provides an electrical connector which can be smoothly connected to a circuit board, and which is firmly held on this circuit board. The electrical connector (10) accommodates signal terminals (30), a ground terminal (50) and supporting terminals (70) inside cavities (25) of substantially the same shape which are formed in a housing (20). The signal terminals (30) and ground terminal (50) have soldering tines (33) of substantially the same shape, while the supporting terminals (70) have supporting legs (80) which protrude by a smaller amount than the tines (33). The tines (33) and supporting legs (80) are installed in a single row on the rear portion of the housing (20). When the electrical connector (10) is attached to a circuit board, the supporting legs (80) drive the electrical connector (10) in the forward direction so that the tines (33) are pressed against the inside surfaces of the corresponding throughholes; accordingly, the electrical connector (10) is firmly held on the circuit board.

Description: ELECTRICAL CONNECTOR FOR CIRCUIT BOARD The present invention relates to an electrical connector, and specifically relates to an electrical connector which contains electrical terminals that are connected by soldering to throughholes formed in a circuit board. In most cases where electrical connectors are attached to circuit boards, soldering is accomplished by means of an automatic soldering apparatus. In this method, the soldering tines for a plurality of electrical terminals are first aligned with the corresponding throughholes; next, these terminal soldering tines are inserted into the throughholes so that the electrical connector is temporarily fastened to the circuit board. Then, all of the soldering connections are made at the same time by means of an automatic soldering apparatus such as a reflow soldering apparatus or the like. Accordingly, most electrical connectors of this type are eguipped with retention legs which are used to fasten the connector to the circuit board temporarily, until the soldering process is performed. These retention legs are constructed so that they protrude from the attachment surface of the electrical connector that is attached to the circuit board, and are engaged with throughholes formed in the circuit board. Ordinarily, such retention legs are disposed adjacent both ends of the connector housing with respect to the direction of the length of the housing. In other words, the dimensions of the housing of the electrical connector are increased by a considerable amount in order to include such a retention leg attachment structure, so that a relatively large surface area is required in order to mount the electrical connector on a circuit board. Furthermore, since attachment of the terminals and attachment of the retention legs are performed separately, the assembly process is made more complicated, which is disadvantageous from an expensive standpoint as well. An electrical connector designed in order to solve this problem is disclosed in Japanese Utility Model Application No. 64-27880. In this electrical connector, electrical terminals including termination sections or soldering tines which are connected by soldering to throughholes formed in the circuit board are disposed in a row inside a housing. The terminating sections of the terminals are lined up in a single row, and a projection which protrudes in one direction with respect to the row of terminating sections is formed on each terminating section. As a result of this construction, the mounting area of the electrical connector is relatively small, and the assembly process is also simplified. However, the following problems arise when the electrical connector disclosed in the application mentioned above is temporarily fastened to the circuit board. When the electrical connector is attached to the circuit board, the edges of the throughholes formed in the circuit board and the projections on the terminals all engage at the same time, so that a relatively large attachment force is required. When the projections on the terminals are engaged with the throughholes in the circuit board, the guidance of the terminals with respect to the throughholes is insufficient, so that attachment cannot be accomplished in a smooth manner. Especially in cases where an attempt is made to guide the terminals by increasing the distance from the positions of the projections to the positions of the tips of the terminals, the terminals protrude more than is necessary from the circuit board following attachment; as a result, tools or other members tend to interfere with the terminals, so that there is a danger of inadvertent release of the temporary fastening of the electrical connector from the circuit board. Accordingly, there is a demand for an electrical connector in which these problems are solved. Furthermore, not only in the electrical connector disclosed in the application mentioned above, but in all electrical connectors which are temporarily fastened to a circuit board, there is a demand for a structure which makes it possible to obtain a relatively large temporary fastening force, so that the temporary fastening is not easily released. The present invention is directed to an electrical connector in which a plurality of soldering tines of electrical terminals that are connected by soldering to throughholes formed in a circuit board are disposed in a row, some of the soldering tines among the soldering tines are constructed so that these soldering tines have a longer flexible portion than the other soldering tines making up the row, and so that these soldering tines protrude by a smaller amount from the bottom surface of the connector housing; these soldering tines are further equipped with projections which are located near the tips of the soldering tines and which protrude in a direction that is substantially perpendicular to the row; and when the connector is attached to the circuit board, the soldering tines which have a different construction receive a driving force in mutually opposite directions, so that the connector is supported on the circuit board. Specifically, the electrical connector of the present invention has a plurality of electrical terminals (signal terminals or ground terminals) fastened by a common fastening device inside a plurality of cavities formed in a housing, and at least one supporting terminal, each of the electrical terminals includes a first soldering tine which protrudes from the housing by a relatively large amount, each of the supporting terminals includes a second soldering tine which protrudes from the housing by a relatively small amount, and in which the protruding tip of the soldering tine is formed into the shape of an arrowhead by a projection which is formed on one side edge of the soldering tine in the vicinity of the protruding tip of the tine, and the first and second soldering tines are arranged so that the respective soldering tines form a row, and so that the projections on the second soldering tines are oriented in a direction that is substantially perpendicular to the direction of the row. The number of supporting terminals which have second soldering tines equipped with projections is preferably two or more, and is also preferably equal to approximately half the total number of terminals or less. Furthermore, in order to achieve stable support of the electrical connector, it is desirable that the supporting terminals be disposed at least in the vicinity of both ends of the connector. It is desirable that the projections described above be composite projections which have a plurality of projecting parts rather than a single projecting part. Such a structure makes it possible to attach the electrical connector to circuit boards of various thicknesses. In addition, it is desirable that the tip ends of the projections be sharpened to an acute angle in order to strengthen the engagement with the throughholes. It is desirable that cut-out areas be formed in the opposite side edges of the second soldering tines from the projections. Such a structure allows the second soldering tines to bend by a sufficient amount inside the throughholes. Furthermore, it is desirable that the cut-out areas in the second soldering tines form inclined surfaces that extend from the tip ends of the second soldering tines toward the base ends of the tines so that these inclined surfaces do not engage the throughholes in the circuit board when the second soldering tines are bent inside the throughholes. Furthermore, the supporting terminals are not limited to use in supporting the temporary fastening of the electrical connector; these supporting terminals may also be additionally used as signal terminals or ground terminals for signal connections or ground connections. Moreover, the throughholes formed in the circuit board need not be arranged in a straight line; for example, it would also be possible to shift the throughholes corresponding to the second soldering tines by a slight amount in the opposite direction from the direction of protrusion of the projections. An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure la is a top plan view of an electrical connector of the present invention for attachment and connection to a circuit board. Figure lb is a front view of Figure la. Figure lc is a right side elevational view of Figure lb. Figure Id is a left side elevational view of Figure lb. Figure 2a is a cross-sectional view along line 2a-2a of Figure lb. Figure 2b is a cross-sectional view along line 2b-2b of Figure lb. Figure 2c is a cross-sectional view along line 2c-2c of Figure lb. Figure 3 is a top plan view of a circuit board to which the electrical connector shown in broken lines is to be attached and connected. Figure 4 is an enlarged right side view of a portion of the electrical connector shown in Figure lc. Figure 5 is an enlarged view of a portion of Figure 3. Figures la-Id show an electrical connector 10 which constitutes a preferred embodiment of the present invention. As shown in Figures la-Id the electrical connector 10 has a dielectric housing 20 and a plurality of electrical terminals 30, 50 and 70 which are disposed in a row inside housing 20. The housing 20 has a key member 21, which protrudes from the engagement surface of the housing 20, a post 22, which is used for alignment during attachment to a circuit board, and extensions 23, which protrude rearward from both sides of the housing 20. Figures 2a-2c show cross-sectional views at the respective positions of the terminals 30, 50 and 70. Figure 2a shows a signal terminal 30 along with a cross section of the housing. The signal terminal 30 has a main body section 31, a tab contact section 32, and a soldering tine (first soldering tine) 33 which protrudes from a bottom surface 21 of housing 20. The signal terminal 30 is press-fitted into a cavity 25 from the rear of housing 20, and is anchored in place by press-fitting projections 35 formed on both sides 34 of the main body section 31. A pressing area 36, which is used to press the signal terminal 30, is located on the rear end of the signal terminal 30. Furthermore, ears 37 formed to the rear of the press-fitting projections 35 act as stop members, which prevent further insertion of the signal terminal 30 into the housing. In addition, the signal terminal 30 is broken from a carrier strip (not shown) leaving portion 38 when the signal terminal 30 is press-fitted into the housing. Furthermore, the tab contact section 32 has tapered surfaces 39 on three sides so that engagement with a mating receptacle contact (not shown) is possible from three directions. Figure 2b shows a ground terminal 50. The ground terminal 50 has a construction similar to that of the signal terminal 30; accordingly, the same reference numbers as those used in Figure 2a are assigned, and the description is abbreviated accordingly. One point of difference between the ground terminal 50 and the signal terminal 30 is found in the tab contact section 52. As seen from Figures 2a and 2b and Figure Id, the tab contact section 52 of the ground terminal 50 has larger dimensions than the tab contact section 32 of the signal terminal 30, and is formed with substantially the same width as that of the main body section 31. This construction is used for so-called "sequential connection", in which signal connections are established after the ground connection has been made. Figure 2c shows a supporting terminal 70. The supporting terminal 70 does not have a tab contact section, but does have a main body section 31 which is substantially similar in shape to the main body sections of the signal terminal 30 and ground terminal 50, and a supporting or attaching leg (second soldering tine) 80. Furthermore, the supporting terminal 70 also includes a pressing area 36, ears 37 and a breaking portion 38, which have functions similar to those of the corresponding parts of the signal terminal 30 and ground terminal 50. Furthermore, press-fitting projections 35 are formed on both sides 34 of the main body part 31. The supporting leg 80 protrudes from the bottom surface 21 of the housing 20 by a relatively small amount. It is seen from Figure lc or Figure Id that the supporting leg 80 protrudes by a smaller amount than the tine sections 33. The actions of these parts will be described later. Furthermore, as shown in Figure 2c, the supporting terminal 70 has an arcuate recess 71, so that a relatively long flexible portion is formed, thus endowing the supporting leg 80 with sufficient elasticity. Projections 81a, 81b, which protrude in a substantially perpendicular direction, are formed on one side edge of the supporting leg 80 near the tip end 82 of the protruding portion of the supporting leg 80. In the present preferred embodiment, the projection 81a is located closer to the tip end 82 and has a first inclined guide edge 83, which extends continuously from the tip end 82. Furthermore, the opposite side edge of the supporting leg 80 in the vicinity of the tip end 82 is cut away so that a second inclined edge 84, which extends in a substantially linear configuration, is formed. The functions of these inclined edges 83 and 84 will be described later. As described above, the plurality of terminals 30, 50 and 70 have a substantially similar press-fitted structure including main body section 31, press-fitting projections 35 and ears 37. Furthermore, cavities 25, which have substantially the same shape and dimensions, are formed in the housing 20. Accordingly, the respective terminals 30, 50 and 70 can be attached in arbitrary positions. Among the seven cavities 25 of the electrical connector 10 shown in Figures la and lb, supporting terminals 70 which include supporting legs 80 are installed in the cavities 25 at both ends, a ground terminal 50 is installed in the third cavity 25 from the left, and signal terminals 30 are installed in the remaining cavities 25. As seen from Figures la through Id, the tines 33 of the signal terminals 30 and ground terminal 50, and the supporting legs 80 of the supporting terminals 70, are lined up in a row. Accordingly, the projections 81a, 81b on the supporting legs 80 project from this row in a substantially perpendicular direction. As is shown in Figure lc, the electrical connector 10 is attached to an end portion of a circuit board 100 from one side. Throughholes are formed beforehand in corresponding positions in the circuit board 100. Figure 3 shows a part enlarged plan view of a circuit board 100 with the electrical connector 10 attached. The circuit board 100 is shown with a portion cut away, and the attachment position of the electrical connector 10 is indicated by broken lines. As shown in Figure 3, eight throughholes 110a through llOh are formed in the circuit board 100. The third throughhole llOh from the right in Figure 3 is used to receive the post 22. The position of the housing 20 is determined by the accommodation of the post 22 in the throughhole llOh. The other seven throughholes 110a through llOg are used to accommodate the terminals 30, 50 and 70; these throughholes are formed in substantially a single row. The throughholes 110a and llOg located at both ends are shifted slightly from this row, and are formed with a slightly larger diameter than the throughholes 110b through 11Of. The process by which the electrical connector 10 is attached to the circuit board 100 will be described below. Figure 4 shows an enlarged side view of the tine 33, supporting leg 80 and surrounding parts. In the first stage of attachment, the tines 33 are aligned with the corresponding throughholes 110b through llOf in the circuit board 100, and tines 33 are inserted into the respective throughholes 110b through llOf. At this time, the attachment surface 120 of the circuit board 100 shown in Figure lc reaches the position of P in Figure 4. In the second stage of attachment, the supporting legs 80 are inserted into the throughholes 110a and llOg. When the circuit board 100 is in the position indicated by P in Figure 4, the inclined edges 83 of the supporting legs 80 make substantial contact with the rear edges 130a of the throughholes 110a and llOg as shown in Figure 5 (since the same action occurs in the throughholes 110a and llOg, a description of the throughhole 110a is omitted from this point on). Furthermore, portions of the respective tines 33 advance into the respective corresponding throughholes 110b through llOf as described above. As a result, the movement of the housing 20 in the direction of the plane of the circuit board is restricted to some extent. When the supporting leg 80 is inserted into the throughhole llOg, the rear edge 130a of the throughhole llOg guides the inclined edge 83 of the supporting leg 80, and the tines 33 are caused to make substantial contact with the front inside surfaces 140 of the throughholes llOe and llOf (see Figure 5; since similar actions occur in the case of the throughholes 110b through llOd, a description of the throughholes 110b through llOd is omitted from this point on) . As a result of this contact, movement of the housing 20 and tines 33 in the forward direction is checked; accordingly, when the supporting leg 80 is inserted further into the throughhole llOg, the supporting leg 80 bends in the direction indicated by arrow A in Figure 4 with respect to the housing 20. Thus, the supporting leg 80 is inserted into the throughhole llOg while being subjected to a guiding action created by the tines 33. When the attachment surface 120 of the circuit board 100 reaches approximately the position indicated by Q, the contact between the inclined edge 83 and the rear edge 130a of the throughhole llOg is released, so that the tip of the projection 81a and the rear inside surface 130b of the throughhole llOg are engaged. When the supporting leg 80 is inserted even further, the relative position of the attachment surface 120 reaches R; however, the amount of bending of the supporting leg 80 is maintained at a substantially constant value from position Q to position R. In the third stage of attachment, the post 22 is inserted into the throughhole llOh. The object of the insertion and engagement of the post 22 in the throughhole llOh is to correct the slight position shift of the housing 20 generated in the attachment process up to and including the second stage described above, so that the housing 20 is installed in a specified position. As is shown in Figure 4, a tapered surface 24 used for guidance is formed around the circumference of the tip end of the post 22, so that smooth insertion into the throughhole llOh takes place. When this third stage is completed, the electrical connector 10 is completely attached to the circuit board, so that the bottom surface 21 of the housing 20 is in substantial contact with the attachment surface 120, and so that the relative position of the attachment surface 120 is position S shown in Figure 4. During the third stage, the attachment surface 120 and the projection 81b intersect each other; in this case, an engagement may be created between the rear inside surface 130b of the throughhole llOg and the projection 81b. In other words, when the electrical connector 10 is completely attached, either one or both of the projections 81a and 81b are engaged with the throughhole llOg. In this way, the electrical connector 10 is fastened in the position indicated by the broken line in Figure 3. Since the projections 81a and 81b are engaged with the throughhole llOg as described above, and the supporting leg 80 is in an elastically bent state, the supporting leg 80 receives a pressing force oriented in the forward direction from the rear inside surface 130b of the throughhole llOg. On the other hand, the tines 33 receive a pressing force oriented in the rearward direction from the front inside surfaces 140 of the throughholes llOe and llOf. Accordingly, the electrical connector 10 is strongly supported on the circuit board 100. As was described above, a portion of the side edge of the supporting leg 80 on the opposite side from the projections 81a and 81b is cut away so that an inclined edge 84 is formed; this makes it possible for the supporting leg 80 to bend sufficiently without contacting the front inside surface 130c of the throughhole llOg. As is shown in Figure 3, the extended parts 23 are positioned on both sides of the engagement positions of the tines 33 and supporting legs 80. The extended parts 23 act to insure stable support of the housing 20 on the circuit board 100. An electrical connector constituting a preferred embodiment of the present invention was described in detail above. However, this embodiment does not limit the present invention; various modifications and alterations may be made. For example, the electrical connector is equipped with a post 22 used for alignment. However, this post 22 is not absolutely necessary. Furthermore, two projections 81a and 81b are formed on the supporting legs 80; however, the number of projections formed could also be one projection, or three or more projections. The circuit board attachment type electrical connector of the present invention is constructed so that engaging projections formed on the soldering tines of supporting terminals are engaged with throughholes in the corresponding circuit board in a state in which the soldering tines of some of the terminals of the electrical connector have been preliminarily inserted into throughholes in the circuit board. Accordingly, as a result of the guiding action of the preliminarily inserted soldering tines, the engagement of the engaging projections can be accomplished smoothly and with a relatively small force. Furthermore, since the electrical connector of the present invention is temporarily supported on the circuit board in a firm manner by first soldering tines and by second soldering tines which possess elasticity, there is no danger that the electrical connector will be inadvertently removed from the circuit board prior to the soldering reflow process.

Claims: CLAIMS 1. An electrical connector for mounting onto a circuit board comprising a housing (20) having a plurality of electrical terminals (30,50,70) secured in cavities (25) in the housing (20), soldering tines (33, 80) on the terminals for engagement with throughholes (HOa-llOg) in the circuit board (100), characterized in that some of the soldering tines (33) are longer than other soldering times (80), protrudes further from a bottom surface (21) of the housing (20) than the other soldering tines (80) and are more flexible; the other soldering tines (80) have at least one projection (81a, 81b) adjacent outer ends (82) thereof; and when the connector is mounted onto the circuit board, the soldering tines (33, 80) as they engage the throughholes in the circuit board generate driving forces in mutually opposite directions thereby attaching and supporting the connector on the circuit board. 2. An electrical connector as claimed in claim 1, wherein the soldering tines (33, 80) are disposed in a row. 3. An electrical connector as claimed in claim 1, wherein the electrical terminals (30, 50, 70) comprise signal terminals (30), ground terminals (50) and supporting terminals (70). 4. An electrical connector as claimed in claim 3, wherein said signal terminals (30) and said ground terminals (50) have tab contact sections (32, 52) extending forwardly from a front surface of said housing (20). 5. An electrical connector as claimed in claim 4, wherein the tab contact sections (52) of said ground terminals (50) extend outwardly further than the tab contact sections (32) of said signal terminals (30). 6. An electrical connector as claimed in claim 3, wherein said electrical terminals (30, 50, 70) have main body sections (31) provided with press-fitting projections (35) for engagement with walls of the cavities (25) thereby securing the electrical terminals therein. 7. An electrical connector as claimed in claim 6, wherein said main body sections (31) includes ears (37) engaging a rear surface of said housing (20) and acting as stop members thereby preventing further insertion of the electrical terminals (30, 50, 70) within the cavities (25). 8. An electrical connector as claimed in claim 3, wherein the soldering tines (80) of the supporting terminals (70) are defined as attaching legs and are formed by arcuate recesses (71) in the supporting terminals thereby endowing the attaching legs with sufficient elasticity. 9. An electrical connector as claimed in claim 1, wherein said housing (20) has a post (22) extending from the bottom surface (21) of the housing for engagement with a throughhole (llOh) in the circuit board (100). 10. An electrical connector as claimed in claim 1, wherein said at least one projection (81a, 81b) includes a plurality of projections (81a, 81b) extending perpendicular to a plane of the other tines (80) and a surface (84) of the other tines (80) opposite the projection (81a, 81b) is tapered.

Inventors: ABE SHINTARO, ABE, SHINTARO
Applicants: ABE SHINTARO, WHITAKER CORP, ABE, SHINTARO, THE WHITAKER CORPORATION
Application year: 1997
Main classification: H01R23
IPC codes: H01R12, H05K3