WO1993014537A1

WO1993014537A1 - Assembly of miniature connector system

Info

Publication number: WO1993014537A1
Application number: PCT/US1992/000413
Authority: WO
Inventors: Rene Augusto Mosquera
Original assignee: Itt Industries, Inc.
Priority date: 1992-01-14
Filing date: 1992-01-14
Publication date: 1993-07-22
Also published as: EP0621985A1; DE69219156T2; DE69219156D1; AU1272792A; EP0621985B1; JP2758078B2; JPH07507652A

Abstract

A method is described for press fitting rows of miniature contacts (50A, 50B, etc.) in a circuit board (34), and then projecting lower end portions of the contacts into holes of a lower connector housing, which facilitates the installation. With the upper end portions (60) of the contacts previously installed in an upper housing (40), push bars (102-106) are inserted between the lower surface (84) of the upper housing and contact mount portions (64) which are to be press fitted into circuit board holes. When the upper surface (124) of the housing is pushed down with great force, forces are transmitted through the push bars (e.g. 106) to the top of the mount portions to press the mount portions down into the circuit board holes. The push bars are then removed. Prior to inserting the lower tips (100) of the contact into the circuit board holes (66), aligner bars (120) are installed between the lower ends of pairs of contacts, to push the contact lower ends sidewardly slightly so their lower tips (100) are aligned with the circcuit board holes (66).

Description

ASSEMBLY OF MINIATURE CONNECTOR SYSTEM BACKGROUND OF THE INVENTION:

SCEM (small computer expendability module) is a type of architecture for small computers wherein various small modules, often in the form of small circuit boards or ^■■tiles", can be stacked at any of several selective positions on a mother board. In one architecture a connector must lie within a circuit board area of about three inches by one third inch. The connector has 400 contacts arranged in six rows in the small area. As a result, the contact centers must be spaced apart along each row by about one millimeter, necessitating the use of very small contacts. A method for installing such large numbers of miniature contacts reliably and at low cost, would be of considerable value.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, a method for installing large numbers of contacts of a connector in holes of a circuit board, and a connector arrangement constructed to facilitate such installation, is provided which enables installation accurately and at low cost. The method includes first installing the upper end portions of the contacts in an upper housing, with the contacts having mount portions with upwardly-facing shoulders lying a distance below a lower surface of the upper housing. An elongated push bar is inserted between the top of the contact mount portions, along a row of contacts, and the lower housing surface. The upper surface of the housing is pushed down with great force, with forces transmitted through the push bars to the tops of the contact mount portions to press down the mount portions into interference fit with the circuit board holes. Thereafter, the push bars are pulled out. Prior to inserting the lower tips of the contacts into the circuit board holes, an aligner is pressed sidewardly against each contact lower portion to deflect it into alignment with a corresponding circuit board hole. Each aligner is preferably in the form of a bar having a greater width than thickness. The aligner bar is initially installed with its width vertical, and thereafter the aligner bar is turned so its width is horizontal to deflect apart adjacent contact lower ends. The lower end portions of the contact, which project from the lower surface of the circuit board, can be installed in a lower housing which has a tapered deflector projecting from its upper surface to deflect the tips of the contact slightly sidewardly into holes of the lower housing.

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 an exploded isometric view of a connector system for connecting modules of an expandable module system.

Fig. 2 is a partial isometric view of the system of Fig. 1, showing three circuit boards and associated connectors.

Fig. 3 is a sectional view of two connectors and two associated circuit boards of the system of Fig. 2, shown in a fully mated position.

Fig. 4 is a partial isometric view of one of the connector assemblies of Fig. 3, with modified end portions.

Fig. 5 is a partial sectional view of one of the connector systems of Fig. 3.

Fig. 6 is a view taken on the line 6 - 6 of Fig. 5. Fig. 7 is a view taken on the line 7 - 7 of Fig. 5.

Fig. 8 is a partial plan view of one of the circuit boards of Fig. 3, shown prior to installation of connector housings and contacts therein.

Figs. 9A - 9H are sectional views of one of the connector assemblies of Fig. 3, showing various stages in the installation of the contacts in the circuit board and in the lower connector housing.

Fig. 10 is a sectional view of the lower housing of one of the connector assemblies of Fig. 3, shown prior to installation of contacts therein.

Fig. 11 is a view taken on the line 11 - 11 of

12 is an enlarged view of a portion of

13 is a view taken on the line 13 - 13 of

14 is an enlarged view of a portion of

Fig. 15 is a simplified isometric view of apparatus used in the installation steps of Figs 9A - 9H.

Fig. 16 is a side elevation view of additional apparatus used in the installation steps shown in Fig. 9F.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Fig. 1 illustrates a connector system 10 for connecting various modules 12, 14, 16 to each other and to a module in the form of a mother board 18. This type of architecture has been designed for use with small computers to allow modules to expand the capability of the computer. Each module 12 - 16 includes a module connector assembly 22 - 26 for interconnecting the modules to each other and to a connector 20 on the mother board. Each of the middle module connectors 22, 24 includes upper and lower housings 30, 32 at opposite faces of the circuit board 34, and multiple contacts extending through the circuit board and into each of the housings 30, 32. Each of the end module connectors 20, 26 has a connector housing on only one side of the corresponding circuit board. Of course, terms such as ^•■upper", "lower", "vertical", etc. are used only to aid in the description of the invention, and the system can be used in any orientation with respect to gravity.

Fig. 2 shows an arrangement which includes only the mother board 18 and two of the modules 12, 16. Fig. 3 illustrates an arrangement that includes only the two uppermost modules 14, 16 and their corresponding connector assemblies 24, 26. Any of the above arrangements and more complex ones can be used.

As shown in Fig. 3, the connector assembly 24 includes upper and lower connector housings 40, 42 lying respectively against upper and lower surfaces 44, 46 of the circuit board 34. A large number of contacts 50 are arranged in six rows 51 - 56. Each contact has an upper end portion 60 that lies primarily within the upper housing 40, a lower end portion 62 lying primarily within the lower housing 42 and a mount portion 64 lying within a hole 66 of the circuit board in interference fit, or press fit therein. The mount portion forms an upwardly-facing shoulder 78 which is used in installing the contact in the circuit board hole. As shown in Fig. 8, the holes 66 of the circuit board, which lie in the six rows 51 - 56, are staggered, in that one column 70 of holes includes holes in only three of the rows (rows 51_r 53, and 55) while the next adjacent column of holes 72 includes holes only in each of the other three rows (rows 52, 54, and 56) . For this reason, a sectional view of the connector assembly may show only portions of contacts in only three rows, with corresponding portions of contacts in the other three rows being hidden. Thus, in Fig. 5 which shows two contacts 50A, 50B, a simple sectional view that would show all of contact 50B would show only part of the other contact 50A.

As shown in Fig. 6, the upper end portion 60 includes a base-received part 70 that lies in interference fit with the walls of a hole 72 in the base 74 of the upper housing 40. The upper end portion 60 also includes a beam 76 which can engage a contact of another connector assembly. The upper end portion 60 also includes an unenclosed or bare part 80 which lies in the space 82 between the upper surface 44 of the circuit board and the lower surface portion 84 of the upper housing that lies immediately around the contact. The space 82 has a thickness Y which is much more than the average thickness A of each contact end portion. The contact also has a lower end portion 90 with a lower tip 92 lying within the lower housing 42 and a base-received portion 94 lying in interference fit with the walls of a hole 96 in the lower housing.

The interference fit between a contact mount portion 64 and a corresponding circuit board hole 66 is a high interference fit, in that this interference fit is the primary means for holding the contact in position, such as against upward and downward forces applied during mating and unmating from contacts of other connectors. In one connector that applicant has designed, the center-to-center spacing of contacts along each row was one millimeter. Each contact was constructed of sheet metal having a thickness of 0.15 mm (six thousandths inch) and a width B of 0.38 mm (fourteen thousandths inch) . Yet, the insertion force required to push the mount portion 64 into the circuit board hole 66, (which was metal plated) was between six to twelve pounds. In order to push the mount portions of all four hundred contacts into their corresponding circuit board holes, a total force of between twenty four hundred pounds and forty eight hundred pounds (i.e. one to three tons) was required. It may be noted that a much lower force such as one pound or less was required to insert the base-received portion 70 of each contact into a corresponding hole 72 of the connector housing.

A large number of contacts to be installed in a single row, are formed simultaneously from a sheet of metal, with the mount portions 64 of all contacts bent to a "C" shape as shown in Fig. 7, and with the upper and lower end portions bent as shown. Different positions of the contact end portions such as 60 with respect to the "C" shaped mount portion 64 can be utilized. Figs. 5 - 7 show a latest and preferred position. As shown in Fig. 7, the contact upper end portion 60 extends from one side 67 of the upwardly- facing shoulder 78, while the space immediately above the other side 68 of the shoulder is unobstructed. A bar portion of the width X lying over the shoulder, will pres down against about two-thirds of the cross-section of the mount portion 64.

With the row of contacts still part of a single sheet by virtue of connector parts (not shown) connecting them to a carrier strip of the sheet metal, the row of contacts are inserted into the row of holes 72 (Fig. 5) in the upper housing 40, this requiring only moderate force, and with each contact being individually accessible, at least from the bottom of the contact. After the rows of contacts have been installed in the upper housing 40, the contacts are severed from the carrier strip. The contacts are now to be installed in tight interference fit with the circuit board holes.

Fig. 9A shows the connector assembly with the upper end portions 60 of the contacts installed in the upper housing 40, and with the contact lower end portions 62 extending down so their lower tips 100 lie at or slightly above the upper surface 44 of the circuit board 34. Although large downward forces are not required at this time, applicant inserts three push elements in the form of bars 102, 104, 106 through the space between the contact shoulder 78 and the lower surface regions 84 of the upper housing 40. Applicant prefers to orient the contacts so the upwardly-facing shoulders 78 of the contacts in two adjacent rows such as rows 51 and 52 can receive the same push bar 106 on them. This reduces the number of individual push bars and enables the contacts to position the push bars so they lie on the shoulders of both rows of contacts. However, it is possible to use a separate push bar for each row of contacts.

In order to assure that the tips 100 of all contacts will enter corresponding holes 66 of the circuit board, it is desirable that each tip 100 lie substantially on the axis 110 of the corresponding hole. Initially, the tips 100 are slightly spaced from the axis 110. Applicant installs elongated aligners or aligner bars 120 between the contacts in adjacent rows such as 51 and 52, slightly above the tips 100 of the contacts. Each aligner bar has a greater width W than its thickness T (Fig. 9B) . Each of the aligner bars is rotatable about an axis 114 extending along the length of the aligner bar and parallel to the contact rows! The aligner bars are initially installed in the orientation shown in Fig. 9A with their widths vertical. As shown in Fig. 9B, the aligner bars are then rotated 90° so their widths are horizontal, and each aligner bar deflects a location 116 on the contact lower end portion 62 lying closer to the tip 100 than to the mount, so the tip lies aligned with the axis 110 of the cylindrical board hole.

As shown in Fig. 9C, a next step is to lower the upper housing 40 by a very small amount, so that the lower tips 100 of the contact actually lie within the board holes 66. Then, the aligner bars 120 are moved horizontally parallel to the lengths of the rows, to withdraw the aligner bars from between the contacts. Fig. 9D shows the apparatus with the aligner bars removed, but with the contact lower tips 100 lying within the board holes 66 so the contact tips will remain in the board holes. Fig. 9E shows a next step, which involves pushing down the upper housing 40 by a considerable amount (e.g. one-half inch) until the contact mount portions 64 lie substantially against the upper surface 44 of the circuit board, and ready to be inserted into the circuit board holes 66.

Fig. 9F shows a next step, where a large downward force F is applied to the upper surface 124 of the upper housing 40 to push down the.upper housing 40. The housing 40 presses down the push bars 102 - 106 which press down the mount portions 64 into the contact holes 66.

As discussed above, a large downward force has to be applied to press fit each mount portion 64 into a circuit board hole 66. The upper housing 40 is preferably molded of a thermoplastic chosen to have a moderately high strength for a thermoplastic, but whose strength is low compared to that of common metals such as bronze or steel. If the entire downward force of perhaps six to twelve pounds per contact had to be applied directly by the lower surface of the thermoplastic upper housing 40, then there could be high pressure on the lower surface of the thermoplastic upper housing 40 which might damage it and result in one or more of the contacts not being pressed reliably into a circuit board hole. Also, as shown in Fig. 5, it is desirable that the hole 72 in the housing base be considerably wider than the contact to enable a curved tip portion 130 to pass therethrough, which would result in only a small area of the housing pressing down against the shoulder 78 of the mount portion. There would even be danger that the C-shaped mount portion could be deformed into the housing hole 72. The use of the push bars such as 106, enables the use of a harder material, such as steel than the thermoplastic material of the housing. Also, the push bar 106 can lie over most of the shoulder 78, except for one side from which the upper contact portion 60 extends, to provide a large area of contact. The downward force applied to the push bars, is applied through the upper housing 40, by a large force F (Fig. 9F) applied against a large area of the housing upper surface 124. The upper housing 40 is pushed down far enough until spacer legs 132 at the bottom of the housing lie substantially against the upper surface 44 of the circuit board. The spacer legs 132 position the upper housing stably on the circuit board. The upper housing 40 can be held down to the circuit board solely by the contacts, although separate fasteners can be used.

After the contacts have been fully installed in the circuit board, the next step is to install the lower housing 42 on the contacts and against the lower surface 46 of the circuit board.

After the contacts and upper housing 40 have been fully installed on the circuit board, a next step is to install the lower housing 42 on the contact lower end portions 62 and on the circuit board. The lower housing has a base 140 with base holes 142 which receive the contact lower end portions. However, the contact lower tips 100 are offset from the base holes 142. Applicant forms the lower housing 42 with tapered deflectors 144 extending upwardly from most of the housing upper surface 146 (the portion of the upper surface that lies between spacer legs 148 of the lower housing) . As the lower housing 42 is moved upwardly, the contact tips engage inclined deflect surfaces 143 of tapered deflectors 144 and are deflected slightly to one side and into the base holes 142. Fig. 9G shows the connector assembly 24 with all parts thereof installed on the circuit board 34. The presser bars 106 are then removed by sliding them horizontally and parallel to the length of the contact rows, out of the space between the upper housing and the upper surface of the circuit board. Fig. 9H shows the connector assembly 24 with all installing apparatus removed.

Fig. 15 is a simplified view of one apparatus 150 which can be used to insert and remove the push bars 102 - 104, and to insert, turn, and remove the aligner bars 120. The apparatus includes a guide device 152 having three rectangular guideways 154 that can guide the push bars 102 - 106 to move them between the bottom of the upper housing and the shoulders of the contact mount portions. Each bar has a tapered forward end 156 to facilitate its insertion. The guide member also has three cylindrical guideways 160 that each receives one of the alignment bars 120. The rear end of each alignment bar is fixed to a cylindrical rod 162 that can slide and rotate within one of the cylindrical guideways 160. The guide device 152 can slide up and down a short distance on a base 164 which guides the guide device 152 in vertical movement. The base 164 has positioning devices 166 with pins 168 that can be received in corresponding holes 170 (Fig. 8) of the circuit board to accurately align the base 164 with the circuit board.

The upper housing 40 (Fig. 9A) with the upper contact end portions installed thereon, can be installed on the push bars 102 and alignment bars 120 by sliding the housing with contacts thereon horizontally over the bars. The aligner bars 120 are then turned to the position shown in Fig. 9B. Then the guide device 152 is moved downwardly a short distance such as several thousandths inch, to the position shown in Fig. 9C, so the lower tips of the contacts enter the circuit board holes. The alignment bars 120 (Fig. 15) can then be turned, or can be left in their position, and then pulled rearwardly in the direction R out of the guide device 152. The guide device is then moved downwardly by a distance such as one half inch, until the contacts and upper housing are at the position shown in Fig. 9E. If the guide device 152 is not to be used to apply large downward pressure to the upper housing, then the push bars 102 - 106 can be pushed further forward in the direction F, as by other bars 170 until the rear ends 172 of the push bar have been pushed forward of the guideways 154.

Fig. 16 shows a next step, wherein the upper housing 40 with contacts 50 installed therein, and with the push bars such as 106 still in place, is installed between the piston 180 and anvil 182 of a press 184 that can apply forces of up to a few tons. The circuit board lies on a support 186 which supports locations on the circuit board immediately beyond opposite sides of the six rows of contacts. A hard rubber plate 190 has been placed on the upper surface 124 of the connector housing 40 to assure that downward forces on the upper surface 124 are uniformly distributed thereon, the hard rubber plate 190 being softer than the more rigid material of the thermoplastic housing 40. The press is then operated to move down the piston 180 to press fit the contact mount portions 64 into the circuit board holes.

Thus, the invention provides a method and apparatus that facilitates the installation of large numbers of miniature contacts in interference fit with a circuit board. The method includes forming each contact mount portion with a largely upwardly-facing shoulder, and forming an upper housing with a largely downwardly-facing surface region spaced above the shoulders. A push bar is installed between the contact shoulders and housing surface region so downward force on the top of the housing can be transmitted through the push bar to the shoulder of the mount portion to apply a large downward force to the mount portion that press fits it into a circuit board hole. The push bars can be installed in a direction parallel to the rows of contacts, and preferably with each push bar lying against shoulders of contacts lying in two adjacent rows. The lower tips of the contacts can be pushed into accurate alignment with circuit board holes, by an aligner that presses against a contact location closer to the lower tip of the contact than to the mount portion. Each aligner can be in the form of a bar having a greater width than thickness, and which is installed with its width dimension vertical, and which is then turned so its width dimension is horizontal to deflect a pair of contact locations apart. The lower housing can be inserted onto the lower end portions of the contacts that project from the lower surface of the circuit board, by moving the lower housing upwardly with respect to the circuit board and upper housing contacts thereon. The lower housing has an upper surface with tapered deflectors that deflect the tip of each contact sidewardly into one of the lower housing holes.

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 that the claims be interpreted to cover such modifications and equivalents.

Claims

IN THE CLAIMS:

1. A method for installing a connector assembly on a circuit board, wherein said circuit board has a plurality of rows of holes and said connector assembly includes an upper housing and a plurality of contacts with upper end portions for lying in a plurality of rows in said housing and a mount portion below the upper end portion, with each mount portion constructed for interference fit into one of said circuit board holes, characterized by: forming each of said contact mount portions with a largely upwardly-facing shoulder, and forming said upper housing with largely downwardly-facing lower surface regions near each of said contact-receiving holes; installing each said contact upper end portion into one of said housing holes so said shoulder of said contact mount portion is spaced below the level of a corresponding one of said downwardly-facing lower surface regions to leave a space between them as seen in a side view; installing a push bar between a plurality of said contact shoulders and said housing surface regions so said push bar can engage both said shoulders and said surface regions; with said mount portions lying above and aligned with said circuit board holes, pressing down against said upper housing and transmitting forces from said lower surface regions through said bar to said shoulders, to press down said mount portions into said circuit board holes.

2. The method described in claim 1 wherein: said contacts are arranged so pairs of contacts in adjacent rows have adjacent shoulder sides as view along the row, wherein the space immediately above each of said adjacent shoulder sides is unobstructed by said contact upper end portions; said step of installing said push bar includes installing it to lie on said adjacent shoulder sides of each pair of a plurality of pairs of said contacts, and to lie between the upper end portions of each said pair of contacts.

3. The method described in claim 1 wherein: said contacts are arranged in a predetermined number of rows, with each row including at least twice as many contacts in the row as said predetermined number of different rows; said step of installing a push bar includes moving it parallel to the lengths of said rows with said push bar lying against the shoulder of all contacts in at least one row of uniformly spaced contacts.

4. The method described in claim 1 wherein: said housing has a plurality of spacer legs extending to a level below said lower surface regions; said contacts each have a lower end portion with a lower tip; each said circuit board hole has a vertical axis; and including pressing an aligner sidewardly against each said contact lower end portion, at a location closer to said lower tip than to said mount portion, to deflect said lower tip sidewardly to a portion centered on a corresponding circuit board hole axis; with said aligner pressed against said contact, moving down said housing and contacts and aligner until said contact tips have passed down at least partially into said circuit board holes, then removing said aligner, and then moving down said housing and contacts until said spacer legs bear substantially against said circuit board.

5. The method described in claim 1 wherein each said contact has an elongated lower end portion extending down from said mount portion thereof, and including: forming a lower housing with a plurality of contact-receiving holes that can each receive said lower end portion of one of said contacts, with said lower housing having an upper surface and having a tapered deflector extending above said upper surfaces of said lower housing, and with each contact lower end portion having a lower tip; pressing said upper and lower housings toward each other until said contact lower tips engage said deflectors, and continuing to press said ^• housings toward each other while said tips are deflected sidewardly by said deflector into one of said lower housing holes, and then pressing said housings toward each other until they lie against opposite surfaces of said circuit board.

6. The method described in claim 1 wherein: said step of pressing down includes laying a plate of material that is more easily deformed than the material of said housing, on top of said housing, supporting said circuit board, and pressing the top of said plate toward said circuit board with a force of a plurality of hundreds of pounds.

7. A method for installing a connector assembly on a circuit board, wherein said circuit board has a plurality of rows of holes that each has a hole axis, and said connector assembly includes an upper housing and a plurality of contacts lying in a plurality of rows in said housing, with each said contact having a mount portion for fitting into one of said circuit board holes, an upper end portion lying in said upper housing, and a lower end portion that has a lower tip, characterized by: positioning said upper housing above said board with said lower tips each lying above a location that is near but spaced from one of said hole axes; pressing an aligner sidewardly against each said contact lower end portion, at a location closer to said lower tip than to said mount, to deflect said lower ti ^' sidewardly to a position centered on a corresponding circuit board hole axis, and with said aligner pressed against said contact, moving down said housing and contacts and aligner until said tips have passed down at least partially into said circuit board holes, and then removing said aligner and moving down said housing and contacts until said housing bears substantially against said circuit board.

8. The method described in claim 7 wherein: said step of pressing an aligner sidewardly includes inserting an elongated aligner bar between the lower end portions of contacts lying in two of said rows and then turning the align bar about an axis extending along the length of the bar; said bar having a greater width dimension than thickness dimension, said step of inserting includes inserting said bar with said width dimension primarily vertical, and said step of turning includes turning said bar until said width dimension is primarily horizontal, said bar width dimension being sufficient for said bar to sidewardly deflect contacts in both of said rows in opposite directions.

9. The combination of a connector assembly and a circuit board that has upper and lower faces, wherein said circuit board has a plurality^' of rows of holes, and said connector assembly includes an upper housing and a plurality of rows of contacts, each contact having an upper end portion lying in said upper housing, a mount portion lying in interference fit in one of said circuit board holes, and a lower end portion projecting generally downwardly from said circuit board, characterized by: said upper housing has lower surface regions lying around each of said contacts and spaced from the upper surface of said circuit board by at least the thickness of each of said contact end portions, and said upper housing having spacer legs extending below the level of said regions and bearing against said circuit board upper surface; said mount portions each have an upwardly-facing shoulder lying about even with the upper surface of said circuit board and spaced below one of said lower surface regions, whereby to enable pressing said mount portions down into said circuit board by the use of push elements lying between said housing lower surface regions and said shoulders.

10. The combination described in claim 9 wherein: each of said contact upper end portions extends upwardly from a first side of said shoulder to leave most of the area immediately above an opposite second side of said shoulder unobstructed; the contacts of first and second adjacent row are oriented so said second sides of said shoulders lie closest to each other, whereby to enable a single push element extending along said first and second rows to lie on the shoulders of contacts of both rows to simultaneously push down contacts of both rows.

11. The combination described in claim 9 wherein: said connector assembly includes a lower housing that has a plurality of holes that each receives said lower end portion of one of said contacts; said lower housing having an upper surface region spaced below said circuit board lower surface with said upper surface region forming a majority of the upper surface of said lower housing, with said housing having a deflector portion extending upwardly from said upper surface region beside each of said holes in said lower housing with each said deflector portion having a deflect surface that extends downwardly and towards a corresponding hole, so when the lower tip of a contact lower end portion moves down it can be deflected by said deflect surface into one of said holes.

12. The combination described in claim 11 wherein: said connector includes at least one elongated deflector lying between two adjacent rows of contacts and projecting above most of the rest of said lower housing upper surface, said deflector having opposite sides that each form a plurality of said deflector portions for one of said two rows of contact lower end portions.

13. The combination of a circuit board having upper and lower surfaces and having a plurality of rows of holes, an upper connector housing lying above said circuit board and having a lower surface, and a plurality of rows of contacts having mount portions that each must be pressed with large force downwardly into an interference fit with one of said board holes, said contacts having upper end portions extending up from said mount portions into said housing and held therein, wherein: each said mount portion has a generally upwardly facing shoulder spaced below said housing; and including a removable push bar extending along at least a first of said rows of contacts and lying closely between said shoulders and said housing lower surface; means for pressing against the top of said housing and against the bottom of said circuit board, to push said mount portions into said board holes by forces of a plurality of hundreds of pounds transmitted through said removable push bar.

14. The combination described in claim 13 wherein each said contact has a lower end, and including: an elongated aligner bar having an axis and extending between the lower ends of contacts of two adjacent rows of said contacts; said aligner, bar having a greater width than thickness with said width being slightly greater than the distance between locations on said contacts lower ends when said lower ends are undeflected; means for turning said aligner bar about its axis until bar locations at opposite sides of said width can each press against said contact locations to temporarily deflect said contact lower ends apart.