High density connector
BACKGROUND OF THE INVENTION 
     Connectors with large numbers of contacts that can be mated and unmated from contacts of corresponding connectors, are useful in a variety of applications, such as to make a large number of connections in large computers. For example, in one application numerous twisted wire pairs lead to the rear of connector frames and connect to pairs of socket contacts in the connector. Very high densities of contacts are required, such as about 400 contacts per square inch in one application. The closely spaced pairs of contacts must provide a known uniform degree of cross talk between contacts with high reliability, and the contact pairs must be easily replaceable in the event that a contact malfunctions. A contact assembly which could meet these requirements would be of considerable value. 
     SUMMARY OF THE INVENTION 
     In accordance with one embodiment of the present invention, a connector is provided with contact assemblies that can be constructed of small size at moderate cost, which are reliable, and which are easily replaced. Each contact assembly includes a pair of sheet metal contacts lying in parallel planes and a dielectric support which holds the contacts at a predetermined spacing. The dielectric support includes a spacer portion of about the same thickness as the space between the forward mating portions of the contacts and which lies therebetween, the support also having a rearward portion molded tightly to the rearward portions of the contacts. 
     In one connector assembly, the spacer portion includes a pair of arms initially molded so they diverge. The rear ends of the arms are connected by living hinges to the rearward portion of the dielectric support. After molding, the arms are pivoted together to lie between the sheet metal contacts, the arms having latches that hold them together when they are brought together. A first of the arms can have a sideward projection near its forward end. The projection snaps into a recess of the connector frame when the connector assembly is installed in the frame, to contain the contact assembly. The recess opens to the front of the frame, so the recess is short and a defective contact assembly can be removed by a tool inserted into the front of the frame while the contact assembly is pulled out of the rear of the frame. 
     The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a socket connector constructed in accordance with one embodiment of the present invention, shown with a mating plug connector. 
     FIG. 2 is a perspective view of a contact assembly of the socket connector of FIG. 1. 
     FIG. 3 is an elevation view of the contact assembly of FIG. 2. 
     FIG. 4 is a side elevation view of the contact assembly of FIG. 3. 
     FIG. 5 is a plan view of the contact assembly of FIG. 3. 
     FIG. 6 is an elevation view of a portion of a string of contacts of the type used in the contact assembly of FIG. 2. 
     FIG. 7 is a view taken on the line 7--7 of FIG. 6. 
     FIG. 8 is an elevation view of the contact assembly of FIG. 3, shown as it is originally molded. 
     FIG. 9 is an elevation view of the support of the contact assembly of FIG. 8, with the arms pivoted together. 
     FIG. 10 is a side elevation view of FIG. 9. 
     FIG. 11 is a view of a portion of FIG. 8. 
     FIG. 12 is a plan view of a portion of the socket connector frame of FIG. 1. 
     FIG. 13 is a view taken on the line 13--13 of FIG. 12, showing the contact assembly of FIG. 3 during insertion, and also after insertion with plug contacts mated to the socket contacts. 
     FIG. 14 is a view taken on the line 14--14 of FIG. 12. 
     FIG. 15 is a partial side elevation view of the plug connector frame of FIG. 1, with part of the frame removed, and showing one set of plug contacts in an extended position and others in a retracted position. 
     FIG. 16 is a perspective view of a connector assembly constructed in accordance with another embodiment of the invention. 
     FIG. 17 is a plan view of a connector assembly constructed in accordance with still another embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates a socket connector 10 which includes a frame 12 with numerous passages 14 that receive contact assemblies 16. Twisted-pair cables or wires 20 connect to the contact assembly and extend rearwardly therefrom. The frame has numerous holes 22 that each can receive a plug contact to mate with the contact assemblies 16. A plug connector 24 can be positioned opposite the front face 26 of the socket connector 10, and can be operated so its numerous plug contacts project into the holes 22. In one connector that applicant has constructed, the holes 22 are paired at a designated distance apart A of 30 mil (one mil equals one thousandth inch) or about 0.8 mm apart, so the contact assemblies must be made very small. 
     FIG. 2 illustrates the contact assembly 16 which includes two socket contacts 26, 28. Each contact 26, 28 includes two spreadable contact arms 29, 30 and 31, 32. Each pair of arms has bite locations 34 that can spread apart so the assembly can receive plug contacts 36, 38 moving along mating paths 40. The forward mating portion 42 of each dual-arm socket contact such as 26 includes a slot 44 that forms the two arms. Each contact also has a rearward end portion 46, 48 which is permanently connected to a conductor 50, 52 of the twisted pair cable or wire 20, as by welding the end of each conductor to a corresponding socket contact. The two contacts 26, 28 are stamped sheet metal parts held in spaced parallel planes (57, 58 in FIG. 4) by a dielectric support 54. 
     The dielectric, or insulative, support 54 (FIG. 2) includes a spacer portion 56 which lies between the forward mating portions 42 of the contacts. Specifically, the spacer portion lies between corresponding arms 29, 31 and between arms 30, 32 of the two contacts, which lie on opposite sides of the mating paths 40. The spacer portion is formed by two spacer arms 60, 62. The dielectric support also includes a rearward portion 64 which is molded around the wire conductors 50, 52 and around parts of the rearward portions 46, 48 of the contacts. The dielectric support also includes hinge portions or living hinges 66, 68 which join the rearward support portion to the spacer arms. The spacer arms initially lie at the positions 60A, 62A. As will be described below, after the arms are molded, they are pivoted together. The arms include a latch device 69 formed by barbs or latches 70, 72 that hold the arms together when they are pivoted together. 
     To form the contact assembly, a string of contacts shown at 74 in FIG. 6 is used, which includes a carrier 76 with multiple contacts thereon. Two contacts 26, 28 are broken off at parting lines 80 and attached to conductors 50, 52 as shown in FIG. 8. The insulation 82 around part of the end portion 84 of the wire 20 will have been removed. The wire with the two contacts 26, 28 are placed in a mold 86 shown in FIG. 8, with a cavity 88. A plastic such as nylon is injected into the mold through a sprue hole 90 that is aligned with holes 92 in the contacts. The plastic forms the spacer arms 60A, 62B in an orientation wherein they spread apart. When the assembly is removed from the mold, the arms at their molded positions 60A, 62A, shown in greater detail in FIG. 11, are pivoted together about the living hinges 66, 68. As the arms are forced together to their use positions, their latches 70, 72 interlock, and the spacer arms are then permanently held together between the contacts. In practice, the plastic is still very warm when the arms are pivoted together which facilitates such pivoting although they could be pivoted together even after the plastic part cools. 
     It can be seen in FIGS. 9 and 10, that the rearward portion 64 of the support includes thin opposite face portions 94, 96 lying beyond the contact locations and also includes sprue-like rod portions 100, 102 that extend through holes in the contacts. 
     After the contact assembly has been formed, it is installed in the connector frame in the manner shown in FIG. 13. As the front of the contact assembly 16 is pressed into a passage 14, a beveled surface 104 on spacer arm 60 is deflected towards the other spacer arm 62. The forward portion of arm 60 (forward of latch 72) is free to bend to allow a projection or retainer 106 on arm 60 to pass along the passage 14. When the contact assembly has been fully installed, the retainer 106 snaps behind a forwardly-facing shoulder 110 formed at the rear of a recess 112 at the front of the connector. The contact assembly is then securely held. A plug contact 36 can be inserted through one of the holes 22 in the frame to spread apart the bite locations 34 on the arms 29, 30 of a contact 26. If a contact assembly must be removed, this is accomplished by inserting a removal tool 114 into the recess 112 to deflect the retainer 106 so the contact assembly can be pulled out by pulling rearwardly on the wire 20 thereof at the same time. 
     FIG. 12 shows the arrangement of the holes 22 and recess 112 that lie at the front end of each passage 14 in the connector frame 12. It can be seen that the passages 14 are of square cross section. The contact assembly 16 is also of square cross section (as shown in FIG. 5). While the contact assembly can be installed in any of four different orientations, only one of them will allow the projecting retainer to snap into place. Personnel will generally install the contact assemblies in the correct orientations, but after installation this can be checked by a moderate rearward pull on the wires, dislodging all but properly installed contact assemblies. 
     The construction of the contact assembly provides many advantages. The provision of the retainer 106 on the plastic spacer removes the retaining features from the electrical contacts. The plastic support locates each sheet metal contact so the inner face such as 26i (FIG. 4) of the contact lies closely against the support 56 and the outer face 26f of the contact lies only a small distance from a wall of the passage in the connector frame. The plastic spacer portion lies at the height of the bites 34 of the contacts to support them as they mate with the plug contacts. The dielectric support is a unitary member that separates all portions of the spaced contacts, so the spacing between the contacts is closely predictable. The two conductors 50, 52 are generally a twisted wire pair, with one of them 50 being at ground potential and the other 52 carrying a signal, and it is desirable to maintain a closely predictable degree of electromagnetic coupling between them. The molding of the support to the pair of contacts helps achieve this. 
     There is a distinct advantage in allowing the retainer 104 to be released from the front of the connector frame (by tool 114, FIG. 13). Generally, there is a very dense thicket or mat of wires at the rear of the frame, as compared to the orderly arrangement of holes at the front of the frame. Applicant can insert the removal tool into the hole of the appropriate contact assembly, and then pull rearwardly on the wire which is believed to correspond to it. If the wire and contact assembly do not pull out, then applicant immediately notes that he has pulled on the wrong wire. The inclusion of a rectangular recess 112 in addition to the holes 22 at the front frame, allows identification of which of the holes (22Y) is for the grounded contact and which (22X) is for the signal contact. The fact that the recess 112 extends by much less than half the front-to-rear thickness of the connector, results in walls of greater thickness B in the frame, which strengthens the frame and allows for closer spacing of the passages. 
     The contacts are mounted with their tails or rearward end portions 46, 48 (FIG. 2) offset from one another. This helps to keep the wire conductors 50, 52 further separated. 
     FIG. 15 shows some details of the plug connector 4. The plug contacts such as 36, 38 are mounted on a slider 120 which can be moved rearwardly by a cam to project the plug contacts into the holes in the socket connector. 
     Applicant has constructed a connector of the type illustrated in FIGS. 1-14. The contacts such as 28 (FIGS. 6 and 7) have a width C of 50 mil (one mil equals one thousandth of an inch), a thickness D of 10 mil, and a height E of 296 mil. The support 54 (FIG. 4) has a height F of 401 mil, and an overall thickness G of 50 mil. The spacer portion 56 has a thickness H of 20 mil, which equals the separation of the contacts. The support has a width J (FIG. 3) of 50 mil except at the projecting retainer 106 which projects sidewardly by a distance K of 13 mil. 
     FIG. 16 illustrates a contact assembly 130 which includes four dual-arm socket contacts 131-134 lying in four parallel planes and spaced apart by three spacer portions 140-142 of a dielectric support 144. Each of the spacer portions 140-142 is substantially the same as the spacer portions of the contact assembly of FIG. 2. The four contacts connect to the four conductors of wires 150, 152. 
     FIG. 17 is a plan view of another contact assembly 160 which includes eight dual-arm socket contacts 161-168 arranged in pairs. Each pair such as the contacts 161 and 162 are spaced apart by a spacer portion 170 of a dielectric support 172. The spacer portion 170 has two wide arms 174, 176 that are connected by living hinges to a rearward portion molded around the rearward portions of the contacts in a manner similar to that for the contact assemblies of FIGS. 1-14. 
     Thus, the invention provides a connector with multiple contact assemblies that each includes at least one pair of sheet metal contacts lying in spaced parallel planes and a dielectric support with a spacer portion between the parallel contacts. The support has a rearward portion molded tightly to the rearward portions of the contacts. However, the spacer portion is free of bonding to the front ends of the contacts. The spacer portion can include a pair of arms joined by living hinges to the rearward portion of the support, with the arms initially molded so they spread apart but are pivotable to positions between the contacts and latchable to each other thereat. The front end of one of the spacer arms forms a plain arm or retainer arm. That retainer arm can bend during insertion into a connector frame passage, and then unbends as the retainer snaps into a recess to hold the contact assembly in place. The contact assembly is especially useful for dual-arm socket contact, although much of the approach can be used for plug contacts. 
     Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art and consequently it is intended to cover such modifications and equivalents.