Electrical connector for cable to circuit board application

Abstract: An electrical connector (10) for connecting individual conductors (27) of an electrical cable (28) to a printed circuit board (11) comprises electrical terminals (26) and a similarly constructed electrical terminal (50). Each electrical terminal (26) is characterized in that it has an actuator arm (32) having a first leg portion (36) a second leg portion (38) a third leg portion (40) and a joining portion joining the first, second and third leg portions (6, 38, 40). An actuator (22) is positioned in an actuation area (44) between engaging surfaces which causes the electrical terminal (26) to be positioned in a home position in the insulating housing (12) As the actuator (22) is moved further into an actuation area (44) the engaging surfaces move into pinched engagement with the conductor (26) of the cable (28).

Description: This invention relates to an electrical connector for connecting individual conductors of an electrical cable to a printed circuit board. Electrical connectors having the capability of interconnecting individual conductors to circuit traces of printed circuit boards exist in the electronics industry. These connectors are mounted onto the circuit board having electrical terminals exposed at a lower edge thereof which make electrical contact with the traces on the circuit board. Electrical connectors also have electrical terminals which accept conductors, for example, of a multi-conductor flat or foil cable, in an electrically conducting manner. One electrical connector in particular includes an electrical terminal housing having through passageways for electrical terminals. The housing has a lower face which mounts approximate to the circuit board and an upper face which accepts a multiconductor cable. The electrical terminals are placed in respective passageways within the connector housing with printed circuit board posts extending beyond the lower face, and cable receiving portions of the terminals disposed proximate to the upper face. The housing also includes a camming member which is movable to open the cable receiving portion of the terminal to accept the cable in a zero insertion force fashion. Release of the camming member returns the camming member to an undeflected position and into contact with the cable. EP-A-385,314 discloses an electrical connector comprising a housing having an upper face and a plurality of conductor receiving openings therein. The upper face of the housing and the openings are fixed relative to a camming member of the electrical connector. The camming member is movable relative to the housing and the upper face whereby, when the camming member is moved to actuate and release the conductor receiving portions of the terminals, the upper face remains fixed relative to the camming member. In EP-A-420,009, an electrical connector is shown comprising an insulating housing having a first conductor receiving face with at least one opening profiled for the receipt of a first conductor. The opening is in communication with a terminal receiving cavity having at least one electrical terminal disposed therein. The electrical terminal has two contact arms extending upwardly from a base section which is spring loaded upwardly under the influence of spring means. The spring means causes the two contact arms to be in engagement with sloped surfaces associated with the terminal receiving cavity. The spring biased base section is movable, relative to the terminal receiving cavity, from an upward wire engagement position to a lower wire receiving position. EP-A-420 009 discloses a connector according to the preamble of claim 1 and a terminal according to the preamble of claim 6. A disadvantage of the above-mentioned connectors is that the electrical terminals in the connectors often become misaligned with the terminal receiving openings, thereby making it difficult to insert the cable in the connector. Another problem with some of the prior art electrical terminals is that they typically had one arm anchored and another arm actuated to move towards and away from the anchored arm so that the flat cable could be inserted therebetween. It was not uncommon for one of the arms to fail to engage the conductor on the flat cable, particularly if the flat cable was not properly positioned between the arms. These problems resulted in a poor electrical connection between the conductors of the cable and the electrical terminals. An object of this invention is to design an electrical connector having means for aligning an electrical terminal in a terminal receiving opening and which has conductive arms which are actuated into pinched engagement with a conductor of a cable. Another object of this invention is to provide an electrical terminal which comprises an actuator arm having a pair of contact arms which can be simultaneously actuated into conductive engagement with the conductors of a flat cable. According to one aspect thereof the present invention consists in an electrical connector as defined in claim 1. According to another aspect thereof the present invention consists in an electrical terminal as claimed in claim 6. An embodiment of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a perspective view of an electrical connector according to a preferred embodiment of this invention; Fig. 2 is a cross-sectional view, taken along the line 2-2 in Fig. 1, showing an electrical terminal mounted in a terminal receiving passageway in the electrical connector; Fig. 3 is a cross-sectional end view, showing an actuator in operative relationship between a first leg portion and a second leg portion of a resilient actuator arm; Fig. 4 is a cross-sectional end view similar to that of Fig. 3, showing a flat cable inserted in an insertion area between the second leg portion and a third leg portion; Fig. 5 is a cross-sectional view similar to that of Figs. 3 and 4, showing the actuator in a fully actuated position so that the second and third leg portions are in pinched conductive engagement with the conductor of flat cable; Fig. 6 is a plan view of the electrical terminal; Fig. 7 is a cross-sectional view, showing the next adjacent electrical terminal used in the electrical connector; Fig. 8 is a plan view of the electrical terminal shown in Fig. 7; and Fig. 9 is a top view of the electrical connector shown in Fig. 1. Fig. 1 is a perspective view of an electrical connector, hereinafter designated electrical connector 10, made according to the present invention. The electrical connector 10 comprises an insulated housing 12 having an upper face 14 and a mounting face 16. The insulating housing 12 has a first wall 12a, a second wall 12b, an end wall 12c and an end wall 12d (Fig. 9). The insulating housing also comprises a plurality of terminal receiving passageways 18 (Figs. 2-5) which open onto the upper face 14. Each terminal receiving passageway 18 comprises a press-fit through opening 20 in the mating face 14 which opens onto the mounting face 16 as shown. The electrical connector 10 also comprises a vertically slidable (as viewed in Fig. 1) cap or actuator 22 having a camming portion 24 (Figs 2-5). The camming portion 24 comprises a first camming surface 24a and a second camming surface 24b. The actuator 22 is conventionally slidably secured to the insulating housing 12, for example, by resilient latches 13 on the end walls 12c and 12d. With reference to Figs. 2 through 6, the electrical connector 10 also comprises a plurality of electrical terminals 26 and electrical terminals 50 which are received in the terminal receiving passageways 18. The terminals 26 and 50 are alternatively positioned in the housing to stagger the printed circuit board posts 30b and 52b which extend downwardly there from. The function of each electrical terminal 26 and 50 is to electrically connect at least one conductor 27 from a cable 28 (Fig. 1) to a circuit (not shown) on a circuit board 11. In the embodiment being described, the cable 28 is a foil or flat flex cable, and each electrical terminal 26 and 50 is conventionally edge stamped from a conductive material. As best shown in Fig. 6, each electrical terminal 26 comprises a base arm 30 having a first end 30a and a solder leg or second end 30b which is soldered to the circuit board 29. As shown in Fig. 3, the second end 30b extends beyond the mounting face 16 when the electrical terminal 26 is mounted in the housing 12. As best shown in Figs. 3-5, the base arm 30 has an enlarged section 30c which permits the electrical terminal 26 to be inserted into a terminal receiving passageway 18 and press-fit into the press-fit opening 20. The electrical terminal 26 also comprises an actuator arm 32 which is resiliently coupled to the base arm 30 by a spring section 34. The actuator arm 32 comprises a first leg portion 36, a second leg portion 38, a third leg portion 40 and a joining portion 42 for joining the first, second and third leg portions 36, 38, and 40. The second leg portion 38 is coupled to the joining portion 42 by a second spring section 48 as shown. The second spring section 48 permits the second leg portion 38 to be biased towards and away from the third leg portion 40. As best shown in Fig. 6, the first and second leg portions 36 and 38 define an actuator area 44 for receiving the camming portion 24. The second and third leg portions 38 and 40 define an insertion area 46 for receiving the cable 28. As shown in Figs. 2, 3 and 6, the second and third leg portions 38 and 40 are normally in the open position. The first leg portion 36 has an engaging surface 36a, the second leg portion 38 has engaging surfaces 38a and 38b, and the third leg portion 40 has an engaging surface 40a. The function and operation of the engaging surfaces 36a, 38a, 38b and 40a will be described later herein. The electrical connector 10 also comprises alternatively positioned electrical terminals 50 (Figs. 7 and 8), as mentioned previously herein. Each electrical terminal 50 comprises an actuator arm 51, a base arm 52, a first leg portion 54, a second leg portion 56, a third leg portion 58, a joining portion 60 engaging surfaces 54a, 56a, 56b, and 58a, a spring section 62 and a second spring section 64 which function and operate substantially the same as the first leg portion 36, second leg portion 38, third leg portion 40, joining portion 42, engaging surfaces 36a, 38a, 38b, and 40a, spring section 34, and second spring section 48, respectively, of the electrical terminal 26. It is to be noted that the base arm 52 is situated adjacent to a first leg portion 54 of the electrical terminal 50, whereas the base arm 30 of the electrical terminal 26 is located adjacent the third leg portion 40. As best shown in Fig. 7, the base arm 52 of electrical terminal 50 comprises a first end 52a which abuts the upper face 14 when the electrical terminal 50 is mounted in the insulating housing 12. The base arm 52 comprises a solder arm or second end 52b which extends below (as viewed in Fig. 7) the mounting face 16 of the insulating housing 12. The base arm 52 has an enlarged section 52c which can be inserted to secure the electrical terminal 50 in the terminal receiving passageway 18. The assembly of the electrical connector 10 will now be described. In the embodiment being described, every other terminal receiving passageway 18 has a press-fit opening 20 located adjacent to the first wall 12a, while the remaining press-fit openings 20 are located adjacent the second wall 12b. The staggered arrangement of press-fit openings 20 permit the electrical terminals 26 and 50 to be arranged so that the second ends 30b and 52b are staggered as best shown in Fig. 1. This staggered arrangement facilitates mounting the electrical connector 20 to the circuit board 11. Each of the electrical terminals 26 are inserted into terminal receiving passageways 18 having the press-fit opening 20 located adjacent to the second wall 12b. The second end 30b of the base arm 30 is guided through the press-fit opening 20 until the enlarged section 30c becomes press-fitted therein. The electrical terminals 50 are mounted in a similar fashion in terminal receiving passageways 18 having the press-fit opening 20 adjacent the first wall 12a. After the electrical terminals 26 and 50 are mounted in the terminal receiving passageways 18, the actuator 22 is slidably mounted on the insulating housing 12 so that the camming portion 24 (Figs. 3 and 7) becomes operatively positioned at the mouth of actuator area 44. As illustrated in Figs. 3 through 5, the first and second camming surfaces 24a and 24b become operatively related to the engaging surfaces 36a and 38a and engaging surfaces 54a and 56a. It should be noted that as the camming portion 24 of the actuator 22 engages the engaging surfaces 36a, 38a, 54a and 56a, the insertion area 46 of each electrical terminal 26 and 50 becomes aligned in a home position in the insulating housing 12. In this regard, the spring sections 34 and 62 enable the actuator arms 32 and 51 to "float" in the terminal receiving passageway 18. When the electrical terminals 26 and 50 are in the home position, the insertion area 46 of the electrical terminals 26 and 50 become operatively aligned with the cable receiving opening 23. As the actuator 22 is moved downward from the open position (Figs. 3, 4 and 7) to the closed position (Fig. 5), the first and second camming surfaces 24a and 24b urge the first leg portions 36 and 54 toward the first wall 12a, and the second leg portions 38 and 56 toward the second wall 12b. The third leg portions 40 and 58 move in direct relationship with the movement of the first leg portions 36 and 54, respectively, so that when the first leg portions 36 and 54 are actuated towards the first wall 12a of the insulating housing 12, the third leg portions 40 and 58 also move towards the second wall 12b. It is to be noted that the second and third leg portions 38 and 40 of electrical terminal 26 and the second and third leg portions 56 and 58 of electrical terminal 50 are urged towards each other as the actuator 22 is moved downward and the camming portion 24 is inserted into the insertion area 44. With the electrical connector 10 so assembled, the electrical connector 10 functions as a zero-insertion force connector, or ZIF connector as it is commonly called. When it is desired to interconnect the conductors 27 (Fig. 1) of a cable 28 to the traces on the printed circuit board 11, the electrical connector 10 is positioned so that the second ends 30b and 52b of the base arms 30 and 52, respectively, become aligned with through holes 11a on the printed circuit board 11. The electrical connector 10 is conventionally soldered to the circuit board 11 so that the second ends 30b and 52b of each electrical terminals 26 and 50, respectively, become conductively coupled to one or more traces on the circuit board 11. A cable 28 is then stripped to expose the conductors 27. The cable 28 may then be urged towards the electrical connector 10 such that the conductors 27 become operatively aligned with the cable receiving area 23 (Fig. 9). The conductors 27 are then urged into the insertion area 46 (Figs. 2-5 and 7). It should be understood that the electrical connector 10 may be provided with any number of terminal receiving passageways 18, such that the number of passageways 18 corresponds to the number of conductors 29 in the cable 28. As illustrated in Fig. 4, the cable 28 is inserted into the insertion area 46, and the conductor 27 becomes aligned with the engaging surfaces 38b and 40a of the second and third leg portions 38 and 40, respectively. The actuator 22 may be moved vertically downward (as viewed in Figs. 3-5). This downward movement of the actuator 22 causes the engaging surfaces 38b and 40a of the second and third leg portions 38 and 40, respectively, to be urged towards each other and into contacting engagement (Fig. 5) with the conductor 27. The second and third leg portions 56 and 58 of the electrical terminals 50 also move into engagement with their associated conductor 27. With the cable 28 in the mounted position shown in Fig. 5, an electrical connection between the circuit on the circuit board 11 and the cable 28 is achieved. Advantageously then, the electrical connector 10 provides electrical terminals 26 and 50 which are capable of floating in their terminal receiving passageways 18, thereby permitting the electrical terminals 26 and 50 to become aligned in a predetermined location or home position by the actuator 22. Also, the electrical terminals 26 and 50 each comprise means for the actuator 22 to actuate a first set of legs which in turn causes a second set of legs to be actuated into engagement with the conductor 27 of the cable 28.

Claims: A low insertion force electrical connector (10) for interconnecting a foil circuit (28) to a printed circuit board (11), said connector (10) comprising an insulating housing (12) carrying a plurality of electrical terminals (26,50) and an actuator member (22), said terminals (26,50) including a printed circuit board contact (30b,52b), a base arm (30,50) and an actuator arm (32,50) comprising a leg portion (36,54) and two contact arms (38,40,56,58) connected by a joining portion (42,51) and extending from the base arm (30,50) by way of a common spring arm portion (34,62) the connector (10) being characterized in that the actuator member (22) includes a camming wedge (24a,24b) insertable between the leg portion (36,54) and one of the contact arms (38,40,56,58). The connector of claim 1, characterized in that said leg portion (36,54) and one of said contact arms (38,40,56,58) extend upwardly from a joining section (42,60). The connector of claim 1 or 2, characterized in that said leg portion (36,54) and said other contact arm (38,56) extend in a direction substantially parallel to one another. The connector of any of claims 1-3, characterized in that said other contact arm (38,56) extends integrally from the contact arm (40,58) by way of a spring portion (48,62). The connector of claim 4, characterized in that said other contact arm (38,56) is positioned intermediate of said leg portion (36,54) and said one contact arm (40,58). An electrical terminal (26,50) for use in an electrical connector for connecting at least one conductor from a foil cable to a circuit, said electrical terminal (26,50) comprising a base arm (30,50), an actuator arm (32, 51) resiliently coupled to said base arm (30, 50), said actuator arm (32, 51) comprising a first leg portion (36, 54), a second leg portion (38, 56), a third leg portion (40, 58) and a joining portion (42) joining said first, second and third leg portions (36, 38, 40, 54, 56, 58), said second and third leg portions (38, 40, 56, 58) defining an insertion area for receiving the foil cable, said terminal (26, 50) being characterized in that said first and second leg portions (38, 40, 56, 58) define an actuator area for receiving an actuator (22), and said second leg portion (38, 56) being resilient so that upon inserting an actuator (22) into said insertion area said first and second portions (38, 56) are urged apart and said second and third portions (38, 40, 56, 58) are urged towards each other and into engagement with the at least one conductor of the foil cable. The electrical terminal (26, 50) as recited in claim 6 characterized in that said electrical terminals are edge stamped from a sheet of conductive material. The electrical terminal as recited in any of claims 6-7 characterized in that said first, second, and third leg portions (36, 38, 40, 54, 56, 58) are generally parallel to said base arm (30, 50). An electrical connector comprising at least one terminal as recited in any of claims 6-8 characterized in that said electrical connector comprises a housing (12) having a plurality of terminal receiving passageways (18) for receiving a plurality of said electrical terminals (26, 50), said housing (12) having an upper surface (14) and a mounting surface (16), said terminal receiving passageway (18) defining an opening in said housing for receiving said electrical terminal (26, 50) and said actuator; said mounting surface having a press-fit opening associated with said terminal receiving passageway for receiving a solder leg (30b, 52b) of said terminal (26, 50) in order to secure said electrical terminal in said terminal receiving passageway (18), said solder leg protruding from said mounting surface to enable the electrical terminal to be mounted on a circuit board. The electrical connector of claim 9, characterized in that the actuator (22) includes camming surfaces (24a, 24b) which cam against edges of the first and second leg portions (36, 38, 54, 56).

Inventors: SOES LUCAS, SOES, LUCAS
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1992
Main classification: H01R23
IPC codes: H01R12, H01R24