GB2163305A

GB2163305A - Backplane connector

Info

Publication number: GB2163305A
Application number: GB08520284A
Authority: GB
Inventors: Lennart Borge Johnson; William Benjamin Walkup; Steven Francis Laychak
Original assignee: Teradyne Inc
Current assignee: Teradyne Inc
Priority date: 1984-08-17
Filing date: 1985-08-13
Publication date: 1986-02-19
Also published as: DE3529218A1; JPH0453076B2; GB8520284D0; JPS61116782A; DE3529218C2; GB2163305B; FR2569309B1; CA1245733A; FR2569309A1

Abstract

A backplane/daughter board connector including a first connector element and a mating second connector element that fits between upwardly extending sidewalls of the first element, the first element being provided with an additional contact carried by one of its sidewalls, and the mating connector element being provided with a further contact carried by a facing outside wall. <IMAGE>

Description

SPECIFICATION Backplane connector The invention relates to a connector for connecting a daughter printed circuit board (PCB) to a backplane.

Backplanes are printed circuit boards or metal plates on the upper sides of which "daughter" PCB's are detachably mounted perpendicularly to the backplanes for easy removal. One way of electrically connecting a daughter board to another daughter board, the backplane, and other circuitry is by a twopiece multiple-contact connector consisting of a first connector element that is attached to the backplane and a mating second connector element that is attached to the daughter board and fits between upwardly extending sidewalls of the first element. When the two elements are joined a plurality of rows of contact posts directed upwardly between the sidewalls of the first element are connected to a plurality of corresponding downwardly directed forked contacts of the second element.

We have discovered that by providing a backplane/ daughter board connector with an additional contact carried by a sidewall of one of the two connector elements and a further contact carried by a facing outside wall of the other connector element an additional connection for distributing current, e.g., for ground or power, can be advantageously provided without increasing the overall size of the connector.

In preferred embodiments, there are grooves in the sidewall of the connector element toward the backplane and a plurality of resilient contact portions extending from the grooves; the contact portions have laterally extending tabs at their upper movable ends to prevent the contact portions from extending too far into the region between the side walls to prevent jamming; there are further recesses in the sidewall near the tops of the grooves to receive the movable ends of the contact portions when they are deflected; a single contact in the connector element toward the backplane has a plurality of contact portions located in the grooves; and the contacts on the other connector element are large enough to contact a plurality of contact portions of a contact of the first connector element.

The structure and operation of the presently preferred embodiment of the invention will now be described after first briefly describing the drawings.

Fig. 1 is a perspective view of a connector for connecting a daughter printed circuit board to a backplane according to the invention.

Fig. 2 is a vertical sectional view, taken at 2-2 of Fig. 1 of the Fig. 1 connector.

Fig. 3 is an exploded diagrammatic perspective view showing a contact of a daughter board connector element of the Fig. 1 connector and the portion of the daughter board connector element on which the contact is carried.

Fig. 4 is an exploded perspective view showing a contact of a backplane connector element of the Fig. 1 connector prior to placement in grooves of sidewalls of a backplane connector element of the Fig. 1 connector.

Fig. 5 is a vertical sectional view, taken at 5-5 of Fig. 1, showing mating of contacts of the Fig. 1 connector in use.

Referring to Fig. 1. there is shown twopiece connector 10 for electrically connecting daughter printed circuit board 1 2 (shown diagrammatically without any electronic components) to backplane 14. Connector 10 includes lower backplane connector element 1 6 connected to backpiane 14 and upper daughter board connector element 20 connected to daughter board 1 2. Secured to backplane 14 and passing upwardly through backplane connector element 1 6 are four rows of signal contact pins 1 8 for mating with a corresponding plurality of forked signal contacts 22 mounted in housing 24 (Fig. 2).

Referring to Figs. 2, 3 and 5, signal contacts 22 of daughter board connector element 20 are forked at lower ends 26 in boxes 28 of plastic housing 24 and extend upwardly and are bent horizontally. The other ends 23 of contacts 22 pass through plastic guide board 30 and holes in daughter board 12, where they are soldered (Fig. 5). Aluminum stiffener 32 is connected between guide board 30 and housing 24 to cover exposed portions of contacts 22 and provide structure to daughter board connector element 20. On an outer face of side wall 34 of housing 24 are ground contacts 36 shown isolated from bousing 24 and in more detail in Fig. 3.

Contacts 36 are secured to wall 34 of housing 24 via vertical tabs 37, secured in place during molding of housing 24, and horizontal tabs 39 bent upward after molding. The lower ends of contacts 36 are inclined to provide guide surfaces 40. Laterally extending prongs 38 of contacts 36 pass through holes in daughter board 12, where they are soldered (Fig. 5). Contacts 36 are approximately 0.008 inchs (0.20 mm) thick and are made of phosphor bronze with 100 microinches (2.54 X 10-3mm) of nickel covered by 20 microinches (5.08 x 10-4 mm) of plated gold.

Referring to Figs. 2, 4 and 5, it is seen that signal contact pins 1 8 of backpiane connector element 1 6 are press fit in backplane 14, and that backplane connector element 1 6 has sidewall contacts 42 provided in grooves 44 of right-hand sidewall 46 extending upward from base 47. Each contact 42 has three contact portions 50 that extend upward from connecting portion 53 through holes 51 to grooves 44. Adjacent to the top of base 47, contact portions 50 bend away from contact region or cavity 54 between sidewalls 46, 56 to fulcrum portion 52. From there they bend back toward and into contact region 54, and at contact points 48 they begin to bend back away from region 54.At the upper movable end of each contact portion 50 is tab 58, which extends laterally behind overhanging portion 60 of sidewall 46. Recess 45 extends further into sidewall 46 at the top of groove 44. Contacts 42 are made of a copper alloy (C72500) and have a welded inlay at contact areas 48 (Fig. 4) of 100 microinches (2.54 X 10-3mm) of nickel covered by 100 microinches (2.54 x 10-3mm) of gold.

In use. backplane connector element 1 6 is connected to backplane 14 by inserting the lower press-fit portions of contact pins 18 and contacts 42 through holes in the backplane.

Daughter board connector element 20 is connected to daughter board 12 by screw 64 through guide board 30 and stiffener 32 and also by solder where ends 23 of contacts 22 and prongs 38 of contacts 36 pass through holes 62 in daughter board 1 2. Contacts 18,22 are used to carry signals. while contacts 36,42 are used to carry ground.

Before insertion of daughter board connector element 20 into contact region 54, tabs 58 bear against overhanging portions 60, owing to preloading forces, and precisely locate the contact points 48 so that they do not extend into contact region 54 so far that there would be jamming during insertion. When daughter board connector element 20 is inserted into contact region 54, contact pins 1 8 are received between forked prongs 26; the upper ends of contacts 42 are bent back slightly by inclined surface 39 and received in recesses 45, and contacts 36 touch contact points 48 of contacts 42, as is shown in Fig.

5. Recesses 45 are provided so that contact portions 50 are only bent at the lower ends to prevent the very large insertion forces that would be required if contact portions 50 were supported at two ends.

In addition to providing ground connections without taking up any extra space on connector 10, a further advantage is that ground contact prongs 38 can be provided on daughter boards 1 2 immediately adjacent to a row of signal contacts 22 to provide a short ground path to permit high-speed switching.

Claims

1. A connector for connecting a daughter printed circuit board to a backplane comprising: a first connector element including a base of insulating material, a pair of first sidewalls of insulating material extending upwardly from said base and spaced from each other to define a contact region between its inwardly directed faces. and a plurality of first contacts extending upwardly from said base in said contact region, and a second connector element including a housing of insulating material having outwardly directed second sidewalls for facing and fitting between said first sidewalls and a plurality of downwardly directed second contacts therein aligned with said first contacts for mating with said first contacts when said housing is inserted between said first sidewalls.

wherein a said first sidewall carries at least one third contact having an inwardly directed third contact portion, and a said second sidewall carries at least one fourth contact having an outwardly directed fourth contact portion for contacting said third contact portion.

2. The connector of claim 1 wherein said first sidewall carrying said at least one third contact has grooves in it and openings to said grooves in its inwardly directed face, there are a plurality of third contact portions in said grooves and exposed to said contact region, and said third contact portions are resilient.

3. The connector of claim 2 wherein said contact portions extend into said contact region, said sidewalls have overhanging portions adjacent to said openings in said inwardly directed face such that said openings are smaller in width than the groove behind said overhanging portion, and said third contactportions have movable ends that are bent away from said contact region and have laterally extending tabs that interact with said overhanging portions to prevent said contact portion from extending into said contact region too far, to prevent jamming.

4. The connector of claim 3 wherein extending further into said sidewall from said grooves are recesses for receiving said movable ends when said contact portions are biased into said grooves.

5. The connector of claim 2, 3 or 4, wherein said grooves communicate with holes through said base. and said third contact pass through said holes.

6. The connector of claim 5 wherein each said third contact has a plurality of said third contact portions that pass through said holes and are joined together under said holes by a connecting portion.

7. The connector of claim 6 wherein said contact portions extend into said contact region between said inwardly directed faces.

said sidewalls have overhanging portions adjacent to said openings in said inwardly directed face such that said openings are smaller in width than the groove behind said overhanging portions, and said third contact portions have movable ends that are bent away from said contact region and have laterally extending tabs that interact with said overhanging portions to prevent said contact portion from extending into said contact region too far, to prevent jamming.

8. The connector of claim 6 wherein each said ccntact portion has a fulcrum portion above its corresponding said hole, said contact portion bending away from said contact region between said sidewalls and back toward said contact region at said fulcrum portion.

9. The connector of any one of claims 1-8 wherein said fourth contact includes a plurality of connection portions for extending through holes in said daughter board.

10. The connector of claim 9 wherein said fourth contact has tabs securing said contact to said face of said second connector element.

11. The connector of claim 2 wherein said fourth contact is adapted to contact a plurality of said third contact portions.

1 2. The connector of claim 7 wherein said fourth contact portion is adapted to contact a plurality of said third contact portions and has a lower portion that is inclined to bias said third contact portions away from said region during insertion.

13. A combination comprising the connector of claim 1. a daughter circuit board connected to one said connector element. and a backplane connected to the other said connector element.

14. A connector for connecting a daughter printed circuit board to a backplane substantially as herein described with reference to the drawings.