High density ZIF card edge connector

The present invention relates to a card edge connector having means so that a circuit card may be freely inserted into and withdrawn therefrom. The connector includes an upper housing slidably mounted on cam means so that upon the upper housing being slid vertically upwardly, contact elements extending upwardly thereinto are forced into the card receiving slot and against a card which may be positioned therein.

U.S. Pat. No. 3,660,803 discloses and describes a card edge connector 
having twice the number of contact elements than normally contained in 
other contemporary card edge connectors. The increased density is achieved 
by positioning the lower portion of each second element behind the lower 
portion of each first element and displacing the upper portion of each 
second element laterally and forwardly so as to position it adjacent the 
upper portion of each first element. 
U.S. Pat. No. 3,899,234 discloses and describes a card edge connector 
having a U-shaped driving member vertically movably positioned in the 
bottom of the card edgereceiving slot. Upon camming the driving member 
upwardly, its parallel side walls engage and displace the contact elements 
which are otherwise resiliently extended into the slot. After the card is 
placed into the slot from above, the driving member is returned to its 
original position so that the contact elements may spring back into the 
slot to electrically engage the conductive traces on the card. 
U.S. Pat. No. 3,982,807 discloses and describes a card edge connector 
comprising a lower mounting member containing contact elements and a 
vertically sliding housing positioned thereover. A rotating shaft drives 
the housing down so that camming surfaces therein push the contact 
elements into electrical engagement with a card which may be positioned in 
the card edge receiving slot. 
The present invention is intended to provide a connector having a high 
density of contact elements such as disclosed in U.S. Pat. No. 3,660,803 
and further being able to receive a card without an insertion force 
thereon being required. More particularly, the connector includes a 
plurality of contact elements positioned in a lower housing and having 
contact surfaces extending upwardly into compartments located along both 
sides of a card edge receiving slot in an upper housing movably mounted on 
the lower housing. Camming means positioned between the lower and upper 
housing move the upper housing upwardly whereby camming surfaces therein 
cam the contact elements in towards the slot to engage conductive traces 
on a card which may be positioned therein. Further, the upper housing 
includes upwardly converging outer side walls to accept an electrostatic 
shield.

With specific reference to FIG. 1, the components of the connector of the 
present invention include a lower housing 10, contact elements 12 and 14, 
cam slides 16 and upper housing 18. These several components, along with 
lever 110 shown in FIG. 5, are structured and assembled to provide a card 
edge connector having a high density of contact elements. These elements 
are cammed into electrical engagement with the conductive traces on a 
circuit card after it has been inserted into the card-receiving slot in 
the connector. The housings and camming means are made from a suitable 
insulative material such as a glass-filled plastic sold by the General 
Electric Company under the trade name VALOX. The contact elements are 
preferrably stamped and formed on continuous strip with the preferred 
material being phosphor bronze and plated with gold over nickel. 
Lower housing 10 has a plurality of cells 22 spaced down the length of the 
housing on either side of an upright center wall 24. Inner walls 26, of 
lesser height relative to the center wall, define the outer extent of the 
cells. Reference to FIGS. 2 and 6 will show these features clearly. Short, 
transverse walls 28 separate cells 22 one from the other. Inner and outer 
passages, 30-i and 30-o respectively extend through the lower housing from 
floor 32 of the cells downwardly to open out on underside 34. Passages 
30-i are adjacent center wall 24 and passages 30-o are adjacent inner 
walls 26. Both walls 24 and 26 are vertically grooved as indicated by 
reference numeral 34. These grooves are an upward continuation of the 
passages. 
Side walls 36 of the lower housing are spaced apart from inner walls 26 to 
define longitudinal slots 38 there between. Several cam followers 40 are 
positioned in and along the slots. 
T-shaped, vertical end walls 42 are provided at the ends of lower housing 
10. The upper end of the walls are slotted as indicated by reference 
numeral 44 and the upper corners are angled as indicated by reference 
numeral 46. 
Lever support member 48 is attached to and extends forwardly from the front 
end of lower housing 10. Slot 50 extends in and along the top of member 
48, intersecting U-shaped, transverse slot 52. 
Pin 54 may depend from end walls 42 as shown in phantom in FIG. 5. These 
pins orientate and stabilize the connector on the circuit board. 
Contact elements 12 and 14 are positioned in the cells in lower housing 10 
with an upper section or cantilever beam extending upwardly into upper 
housing 18 (FIGS. 6 and 7), a retaining section in passages 30, and a 
lower section extending downwardly from the lower housing for insertion 
into plated-through holes in a circuit board. Each cell accommodates two 
elements; i.e., one element 12 and one element 14. In FIG. 1, elements are 
omitted for sake of clarity. Elements 12 are positioned in passages 30-i 
and accordingly are referred to as the inner elements. Elements 14 are 
positioned in passages 30-o and are referred to as the outer elements. 
The stucture of the elements are shown in FIGS. 3-a, 3-b, and 4-a, 4-b. 
With reference now to the drawings in those figures, 3-a, 3-b illustrate 
element 12; i.e., the inner element, and 4-a, 4-b illustrate element 14; 
i.e., the outer element. The preferred method of making the elements is by 
stamping and forming them on a continuous strip as indicated by carrier 
strip 56. The elements can be stored as strips on reels (not shown) and 
gang inserted into lower housing 10. Reference numeral 58 indicates the 
score line for breaking the carrier strip away from the elements after 
insertion. 
With regard to both inner and outer elements, reference numeral 60 
indicates the cantilever beam, numeral 62, the retaining section, and 
numeral 64, the lower section. The free end of the cantilever beam carries 
contact surface 66 which may be plated with a noble metal and which 
engages the traces on the card inserted in the connector (FIG. 7). A 
concavo-convex portion below the contact surface provides camming surface 
68 on the convex side. 
Retaining section 62 includes plate portion 70 and dimples 72. 
Lower section 64 includes a lead 74 for insertion into a plated-through 
hole in a circuit board. The lead also can be a compliant pin type such as 
disclosed in U.S. Pat. No. 4,186,982. 
Both retaining section 62 and lower section 64 are thicker than upper 
section 60 to provide support both in the lower housing and in the circuit 
board. The thinner upper section is required for resiliency. 
Contact elements 12 differ from elements 14 in substantially two respects. 
The concavo-convex portion defining camming surface 68 is horizontally 
offset relative to the longitudinal axis of element 12. Cantilever beam 60 
is attached to the left side of retaining section 62 in element 12 and on 
the right side in element 14. These differences are required so that the 
two elements can be loaded in one cell without interference. Other 
differences such as length exist but are not significant from the 
viewpoint of crowding a large number of contact elements in a connector. 
Cam slides 16, FIG. 1, are elongated members structured to be slidably 
positioned in slots 38 in lower housing 10. A series of cam ramps 76 are 
provided along the bottom edge of the slides, these ramps cooperating with 
cam followers 40 in slots 38 to move the slides vertically as they are 
being moved horizontally, all in a well-known manner. 
A longitudinal groove 78 is provided on the inside surface of the slides 
adjacent the top edge. 
Holes 80 are provided in the front end of the slides to receive pins on the 
lever shown in FIG. 5. 
With reference to FIGS. 1 and 6, upper housing 18 is an elongated member 
which is attached to lower housing 10 and which is raised and lowered by 
operation of cam slides 16. 
The outer surfaces of sidewalls 82 of the upper housing have lower parallel 
portions 84 and slanted or converging upper portions 86. L-shaped members 
88 depend from the bottom edges of the side walls with the horizontal 
portion thereof adapted to ride in grooves 78 on cam slides 16. 
The inside area of upper housing 18 is divided into cells 90 by a series of 
transverse, vertical walls 92 which are slotted down the middle to provide 
a card edge receiving slot 94. These walls help stiffen the side walls of 
the upper housing against distortion when the contact elements are cammed 
into and out of engagement with the card. With the components assembled, 
walls 92 are in alignment with transverse walls 28 in lower housing 10 and 
cells 90 are in alignment with cells 22. 
Transverse, vertical walls 96 extend a short distance into cells 90 from 
the side walls to provide a barrier between the cantilever beams 60 of 
adjacent contact elements. 
The specific structure of the inside surfaces of sidewalls 82; i.e., the 
outer wall defining cells 90, can best be seen in the cross-sectional 
drawing of FIG. 6. The outer wall on each side of a cell, indicated 
generally by reference numeral 98, have two vertical portions, one on each 
side of short transverse wall 96. Each cell then has four such portions, 
two on each side of slot 94. Each vertical portion has a beveled cam 
surface, indicated by the reference numeral 100. One such cam surface is 
located either higher or lower on the wall than the adjacent cam surface; 
i.e., the cam surface on the same wall on that side of the cell. 
Accordingly, the higher positioned cam surface is further referenced by 
the addition of letter "h" to the numeral 100; thus 100-h. The lower 
positioned cam surface is referred to by the letter "l"; thus 100-l. 
Facing cam surfaces are unlike; i.e., a high cam surface 100-h looks 
directly across slot 94 at a low cam surface 100-l. 
The openings on the slanted sidewalls are passages made by the core pins in 
molding the upper housing. FIG. 1 shows one of the two identical, 
longitudinal ends 102 of upper housing 18. A vertical wall 104 is slotted 
as a continuation of card edge receiving slot 94. Bracket 106 defines a 
vertical channel 108 which slidingly receives the upper ends of end walls 
42 on lower housing 10. 
Lever 110, shown in FIG. 5, has two spaced apart, parallel members 112 
joined by pin 114. Further, a pin 116 projects laterally from opposite 
surfaces of members 112. 
In an assembled connector of the present invention, FIGS. 5, 6, and 7, 
contact elements 12 are positioned in lower housing 10 with the retaining 
section 62 in inner passage 30-i. The retaining section 62 on contact 
elements 14 are positioned in outer passage 30-o. Camming surfaces 68 face 
outwardly and contact surfaces 66 face inwardly on both elements. 
Cam slides 16, attached to lever 110 by pins 116 entering holes 80, are 
attached to upper housing 18 via L-shaped members 88 and grooves 78 and 
that sub-assembly lowered onto lower housing 10 with the cam slides being 
received in slots 38 and the upper portions of the T-shaped end walls 42 
sliding up into openings 108. Pin 114 slides into transverse slot 52 in 
lever support member 48. 
Upper sections 60 of contact elements 12 and 14 are received in cells 90 as 
shown in FIG. 6 with contact surfaces 66 facing into slot 94 and camming 
surfaces 68 facing the outer walls. In the FIG. 6 position, the contact 
surfaces are within the cell area and the camming surfaces are above cam 
surfaces 100. The side view seen in FIG. 5 shows slides 16 resting on the 
floors of slots 38. FIG. 5 also shows the connector, indicated generally 
by reference numeral 118 positioned on circuit board 120. 
As described above and as shown in FIGS. 5 and 6, the contact surfaces 66 
on adjacent contact elements 12, 14, on each side of slot 94, are located 
at alternating upper and lower contact surface positions, and the elements 
which face one another across the slot, such as elements 12 and 14 in the 
foreground of FIGS. 5 and 6, are not at the same contact surface position. 
This permits the connector to be used with cards having rows of 
alternating upper and lower contact pads, as is described hereinafter. 
With the connector in the FIGS. 5 and 6 mode, card 122 may be freely 
inserted into slot 94. Upon pivoting lever 110 upwardly, cam slides 16 are 
drawn forwardly and, riding up on cam followers 40, the slides rise 
vertically and so does upper housing 18. Cam surfaces 100 in cells 90 
engage camming surfaces 68 and the contact surfaces 66 are forced inwardly 
against conductive traces 124 and 126 on card 122. Note that the contact 
surfaces on contact elements 12 engage the lower traces 126 and the 
contact surfaces on elements 14 engage higher traces 124. 
Card 122 may be withdrawn from the connector by pivoting lever 110 back 
down to the FIG. 5 position.