Electrical connector and method of making an electrical connector

Abstract: An electrical connector (30) and a method of making includes a base housing (40) holding contacts (41) on close spacing and a face housing (50) fitted onto the base housing to protect the contacts. The base housing (40) includes an alignment post (46) integrally formed with the contacts as intercoupled by a carrier section (37) to tie the contact position and alignment post position together dimensionally. The alignment post includes a slot (45) receiving a fastener (35) fitted therein with barbs (37) projecting outwardly to latch the post and thereby the base and face housings to a printed circuit board for surface mounting to the traces of the board.

Description: This invention relates to an electrical connector and method of making such connector; and more specifically to a connector and method for use on a printed circuit board (PCB) wherein contacts are insert molded with the contacts intercoupled on the pitch of stamping and with an alignment post integrally formed with the housing during insert molding. As various electronic apparatus has become more compact and available, areas on PCB's have become more restricted, needs to provide contacts for higher densities have developed. In recent consumer electronic appliances and devices for office automation it has developed-that connectors are needed wherein contacts in substantial number, twenty or more, having a 0.5mm to 0.635mm center line pitch with 1mm or lower spacing between contacts in adjacent rows are necessary. An example of such requirements is disclosed in, for example, Document JP-A-32 72 827. Figures 5 and 6 of this application, labeled herein as prior art, illustrate such connector to include a base housing 11 retaining a plurality of contacts 17 in two rows, upper and lower, and a cap or face housing 10 to be assembled integrally with the base housing 11 for protecting the contacts. The face housing includes screw holes 22 for mounting the assembled electrical connector on a panel, a PCB or the like. Both housings 10 and 11 are molded from a suitable engineering plastic material and the face housing is assembled as an integral part with the base housing by inserting the latching arms 18 thereof into latching openings 12 of the face housing. In molding the two housings which must intermate, the positioning of contacts in the base housing can be critical to the tolerances of such housings, particularly in the miniature and high density electrical connectors with 1mm or shorter contact pitches as mentioned above. Additionally, this fine pitch of contacts and the line width on printed circuit boards to which the connectors must be connected make the alignment of the arrays of contacts quite critical, particularly in the very fine pitch applications heretofore mentioned. Accordingly it is an object of the present invention to provide a miniature, high density electrical connector particularly suited for PCB mounting with lmm or less contact pitch. It is a further object to provide a method of making a connector wherein pitches of lmm or less are contemplated. It is still a further object to provide an electrical connector having high density electrical contacts wherein the alignment between contacts and a connector housing is assured. These problems are solved according to the invention by an electrical connector according to claim 1 as well as by a method of making an electrical connector according to claim 6. Dependent claims 2 to 5 and 7 to 8 exhibit advantageous non-trivial improvements. The electrical connector according to the present invention retains a plurality of contacts in a base housing at a constant spacing and includes an alignment post formed integrally with the base housing at at least one end thereof. In making the connector, contacts are intercoupled to a so-called carrier at at least one end thereof and are insert molded into the base housing. Simultaneously, one or more alignment post is formed with the base housing. As a result, the position of each contact is accurately determined with respect to the base housing and also directly determined with respect to the alignment post. Subsequently, a face housing is assembled to the base housing to protect the contacts as mounted and carried by the base housing. It is to be noted that the position of each contact with respect to a printed circuit board is directly determined by virtue of the alignment post integral with the base into which the contacts are molded rather than indirectly by way of the face housing and hardware thereon. The contacts carry die stamping tolerances into the assembly. Additionally, the alignment housings are made to include slots therein extending along the length thereof and fasteners in the form of stampings having resilient spring sections and projections such as bars fitted therein to extend therefrom to latch the connector in position relative to holes in a printed circuit board or the like. Additionally interdigitating contacts as stamped with the carriers or intercoupling sections overlapped to place the contacts on very close centers with one end thereof are embraced, the contact end overlapping to form two rows of contacts and with the other end forming surface mounting sections arranged in the same plane for soldering to the circuit tracers of a printed circuit board. The invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a exploded and perspective view of an embodiment of a receptacle type of electrical connector in accordance with the present invention. Figure 2 is a partially sectioned and elevational view of the connector of Figure 1. Figure 3 is a partially sectioned and elevational view of the base housing and contacts of the invention. Figure 4 is a plan view of the connector of Figure 3 showing the method of the invention in relation to the presence of intercoupling sections for the contacts. Figure 5 is an elevational and partially sectioned view of a plug type of electrical connection in accordance with the invention. Figures 6 and 7 are perspective and sectional views of a connector in accordance with the prior art. Referring now to Figure 1 there is illustrated in an exploded perspective view an embodiment of a receptacle type electrical connector in accordance with the present invention. The connector 30 is a two piece structure including a base housing 40 and a face housing 50. The base housing 40 is preferably made by molding insulating material such as a glass filled polyphenylene sulfide (PPS). The base housing has a plurality of contacts or terminals 41 comprising receptacle contact sections 42 in upper and bottom rows at the front or mating end of the housing and surface mount (SMT) terminal sections 43 at the rear end in a common plane. At both ends, there are formed block members 44 integral with the housing having slots 45 extending therein and additionally having dovetail engaging projections 48 in or on the upper central surface of each block member. Substantially circular alignment posts 46 are formed on the bottom surfaces of the block members to project down from the body of the base housing 40. The slots 45 continue from the upper surface of the blocks well down into the post 46 to accommodate a fastener 35 having a pair of resilient legs 36 formed therein. The fastener 35 is made by stamping a resilient sheet metal material into the profile shown. Each of the retention legs of fastener 35 includes a series of barbs 37 projecting outwardly therefrom and the fastener is given a dimension so that the barbs 37 protrude from the lower portions of slots 45 in the manner shown in Figure 2. Although not shown it is to be understood that the connector formed of base housing 40 and 50 and the contacts contained thereby are mounted on a printed circuit board by extending the posts 46 through holes or apertures in such board, the holes being related dimensionally to traces on the upper surface of the board that are to be inter- connected by the connector. As shown in Figure 1, the projections 48 are formed on the upper and bottom front ends of the base housing 40 for engaging with the inner surface of the face housing 50 and retaining the housings together. The face housing 50 is preferably made by molding, for example, a liquid crystal polymer material to include a d-shaped hood section 51 projecting and formed on the front face of the housing. Two rows of contact receiving cavities 52 are formed through the face housing extending from the rear surface toward the front surface separated by vertical walls. When the housings 40 and 50 are mated together a contact section 42 of each contact 41 passes into cavity 52 and is isolated from adjacent contacts by the walls there between. Flat plate sections 53 are formed at both sides of the face housing 50 to correspond with the upper surfaces of block members 44 of the base housing 40. Dovetailed grooves are formed in the bottom surfaces of plate sections 53 dimensioned to engage the dovetail projections 47 of base housing 40. In order to assemble and integrate the housings 40 and 50, the fasteners 35 are pressed into slots 45 of the base housing 40 fully down within the slots to a point of clearing the dovetail projections 47. Thereafter the housings are brought together by inserting the dovetail projections 47 of housing 40 into the grooves 54 in the face housing 50 in the direction represented by arrow P in Figure 1. Assembly is complete when the latch projections 48 of housing 40 butt against shoulders 49 in the inner wall of face housing 50 as shown in Figure 2. Also illustrated in Figure 2 through the cross sectional view of a receptacle type electrical connector 30 is the assembly of housings 40 and 50 as a unitary member. As can be appreciated from Figure 2, the contacts sections 42 of contacts 41 are disposed alternately in upper and bottom rows 42a and 42b. A plug housing or an edge of a printed circuit board having contact pads can be mated with the connector 30 by being inserted between the rows 42a, and 42b. The face housing 50 includes an opening 55 at the front surface adapted to receive the insertion of a mating plug housing or printed circuit board or the like. Face housing 50 is slidably assembled into the base housing to maintain proper isolation between the adjacent contacts and protect the contacts 41 from damage or degradation in performance due to external shock or dust. Figures 3 and 4 show the steps of making the receptacle type electrical connector 30, particularly the base housing 40 thereof which is illustrated in Figure 1. In Figure 3 a side sectional view of the housing 40 is shown with a plan view of such housing shown in Figure 4. To be noted is the arrangement of contacts 41 in the form of two carrier strips which are laid one over the other interdigitated to form alternate contacts which can be positioned in two separate rows, forming the contacts 42a and 42b at the contacting end thereof. As can be seen in Figure 4 the carrier strips 38 which form intercoupling sections 37a and 37b are laid one over the other and spaced apart as shown in Figure 3. As can also be discerned in Figures 3 and 4 while every other contact of the connector housing is associated with a common carrier strip 37a or 37b the opposite ends of the contacts are interconnected by intercoupling sections 39 intercoupling an adjacent pair of contacts. In order to maintain alignment during insert molding, the contacts are kept on the centers as stamped by the carriers 37a and 37b and intercoupled as at 39. The carriers include index holes 37c as shown in Figure 4. These holes facilitate laying the contacts in a jig or fixture which is in turn placed into an insert mold or formed in the mold to allow insert molding of the housing 40. After insert molding, the contacts including the carriers and the coupling section are bent so that reliefs shown as 41a and 41b at the rear and front of the contacts respectfully allow removal of the intercoupling sections by either cutting or bending so that the contact material breaks at such reliefs. This will leave a substantial number of contacts 41 as shown in Figures 1 and 2 on the precise dimensional spacing as die stamped. Moreover since the contacts are insert molded and the posts 46 and slots 45 therein are integrally formed, the posts 46 will be aligned with the contacts precisely. Also to be appreciated, the tie-in dimensionally of posts 46 to the positioning of the contacts in the several rows of contacts differs from the prior art wherein the alignment of the connector is dependent upon holes and mountings associated with the face housing, as shown by housing 10 in Figure 6. Also to be noted in Figures 1 and 2 is the flat area 43 formed at the rear end of each contact which serves to provide a surface mounting by soldering to a trace on a printed circuit board. The areas 43 may be pretinned or coated with solder so as to allow reflowing by any number of available processes to the circuit traces of a board once the housings of the connector are mounted on such board by inserting posts 46 in holes in such board to a point where the projections on barbs 37 engage the board material. Figure 5 shows a cross sectional view of a connector similar to that described but with a plug type connector 60 made to include a base housing 40 and a face housing 50 with the face housing including a central divider portion 61 in the matter shown and with the contacts 41 having flat portions which are positioned dimensionally to fit within the contacts 41 of the receptacle housing, engaging respectively the contact points 42a and 42b of the receptacle half as shown in Figures 1 and 2. As can be discerned from Figure 5 the plug half 60 would include alignment post 46 and projections 36 carrying barbs 37 in the same manner as described with respect to the receptacle half. It is also contemplated that either half may be surface mounted in the manner described with the other half given a different sort of termination to either flat flexible circuits or to discreet wires utilizing a suitable interconnection in lieu of the flat sections 43. It is also contemplated that both plug and receptacle connector halves may be manufactured by insert molding tying the dimensioning of the contacts to the positioning of alignment posts 46. Indeed the invention fully contemplates that the contacting sections of the contacts may be arranged in numbers of rows rather than two and that the terminal sections may be other than SMT. Additionally, the use of the retention legs of the fasteners with respect to the alignment posts is preferable but may be substituted by other means for retaining the connector in position prior to enduring soldering. According to the present invention the ability to achieve high density electrical contacts having contacts on 1.0mm center line pitch or down to 0.05mm center line pitch for both rows of contacts is made possible.

Claims: An electrical connector (30) including: a) a base housing (40) having an array of contacts (41) extending therefrom and b) a face housing (50) c) adapted to fit onto said base housing (40) with means (48) to cooperatively latch said housings together with a face housing extending over and protecting said contacts, characterized in that: d) at least one alignment post (46) projecting from the said base housing to align the said housing and connector relative to circuits on a printed circuit board or the like with the said posts being formed integrally with the base housing; e) and the base housing being moulded around the contacts (41) on the centers of die stamping to provide a commonality of dimensional reference between the alignment post and the said contacts. The connector of claim 1 characterized in that: a) said post (46) includes a slot (45) therein and a fastener (35) inserted in said slot; and b) said fastener including spring legs (36) with barbs (37) projecting from said post to secure said housing and connector to a printed circuit board or the like. The connector of claim 1 or 2 characterized in that said contacts (41) are comprised of two arrays (42a, 42b) of stamped contacts interdigitated to provide centers in the connector that are half the centers of the contacts as stamped. The connector of claim 1, 2 or 3, characterized in that said contacts (41) include one end (42) projecting from the said base housing (40) to provide an interconnection to a further interconnection and the other end (43) arranged in a common plane for surface mounting to a printed circuit board or the like. The connector of claim 1, 2, 3, or 4 characterized in that said base housing (40) and face housing (50) include matable tongues and grooves (48, 54) to cooperatively secure the said housings together. A method of making an electrical connector comprising the steps of: a) forming the desired shape of a plurality of contacts (41) on the constant pitch of contact stamping with the contacts intercoupled by a section (37, 39) at least at one end, b) insert molding a housing (40) around said contacts on said contact constant pitch to include at least one alignment post (46) extending from said housing integrally formed with said molding, and c) providing a plurality of discrete contacts (41) by removing the said intercoupling section (37, 39) from the ends of said contacts. The method of claim 6 characterized in that the said forming step includes interdigitating two rows of contacts with each row separately intercoupled (37, 39) at least at one end. The method of claim 6 characterized in that the said forming step includes providing contacts (41) intercoupled (39) on a contact engaging end and includes the further step of providing a face housing (50) covering said contact engaging ends following the removal of the intercoupling section of the contacts.

Inventors: ISHIKAWA SHIGERU, ISHIKAWA, SHIGERU
Applicants: WHITAKER CORP, THE WHITAKER CORPORATION
Application year: 1991
Main classification: H01R13
IPC codes: H01R12, H01R13, H01R43