Connector mechanisms

A connector mechanism for electrically connecting two structures 22, 24 carrying conducting lines 26, comprises fixed contacts 28 on one of the structures and floating contacts 30 on the other of the structures, the floating contacts being free to move towards and away from the fixed contacts and across the fixed contacts as independent motions, under the control of a common actuator 50, 52, 54, each floating contact being an electrically integral part, carried by the actuator, of a flexible conductive film 34. The provision of a shroud 46 on the fixed contact structure carrying markings 48A, 48B registered with the fixed contacts 28 and engaging the actuator provides coarse location, while the flexibility of the web and the mounting of the floating contacts on a resilient pad 38 on a carriage 50 provided with cam followers 54 riding on a multi-throw linear cam 52, together comprising the actuator permits independent locating and wiping motions, independently of each other and at selected pressures, including zero pressure on insertion, making the connector mechanism an effective ZIF connector.

FIELD OF THE INVENTION 
The present invention relates to connector mechanisms for releasably 
electrically connecting two structures which carry conducting lines and 
provides a solution to the problem, common to such connector mechanisms, 
of accommodating both the damage free engagement/dis-engagement of the two 
separable portions of the connector mechanism as well as establishing the 
positive and accurate the internal electrical coupling required. The term 
"Zero Insertion Force (ZIF)" Connectors is frequently applied to such 
mechanisms. 
BACKGROUND OF THE INVENTION 
It is normal for data processing equipment to be aggregated of a plurality 
of cards, which have electrical components mounted thereon and which have 
the inter-component and intercard electrical connections provided by 
conducting lines formed on the card surfaces. Such cards are assembled 
into a housing and/or onto a board, also incorporating conducting lines, 
the function of which is to transmit electrical signals from component to 
component, card to card and from card to board and so on. Further, repairs 
are effected by card replacement. The function of the connector mechanisms 
to which the present invention relates is to inter-connect the conducting 
lines on any pair of abutting structures, whether these be cards, boards, 
cables or housings. 
The prior art contains many proposed forms of such connectors and reference 
is made to but a selection of these, by way of example, the criterion for 
selecting being that all the prior art selections involve the use of a 
flexible conductive member, in some form or other, and one of the basic 
elements of the present invention is a flexible conductive film though the 
present invention uses its film in a way that is not to be found in the 
prior art. U.S. Pat. No. 3,149,896 to Hall J. R., relates to connecting a 
multiple conductor cable to a rigid circuit element by clamping the cable 
into a housing in such a way that its conductors are coupled to pins in 
the housing which extend into a slot into which the rigid circuit element 
is pushed, displacing the pins and establishing the required electrical 
connections. This is a typical example of the kind of connector which is 
virtually certain to damage the conducting lines of any rigid circuit 
element which is repeatedly pushed into the slot. U.S. Pat. Nos. 3,825,878 
to Finger C., and 4,227,767 to Mouissie B., are essentially similar, as 
is, to some extent, the arrangement described in IBM Technical Disclosure 
Bulletin, Vol. 25, No. 1, June 1982, pages 370 and 371, although it hints 
at a modification which might avoid insertion damage in that the housing 
may be arranged with extension to permit it to be used in the manner of a 
so-called "Bull" clip. 
U.S. Pat. Nos. 3,573,704 to Tarver C. R., 3,629,787 to Wilson J., and 
4,116,516 to Griffin W. L., all relate to connectors which may avoid the 
damage problem since they are dismantled and reassembled around the 
elements to be interconnected but cannot be thought of as being 
particularly convenient. The last of these three patents deals with the 
establishing of electrical connections to the various layers in a 
multi-layer cable. 
U.S. Pat. No. 3,977,756 to Rodondi A. F., relates to a connector in which a 
flexible printed circuit is wrapped around a rigid printed circuit and 
then is secured in its operative condition by a cap which is forced 
thereover. In this case, apart from being limited in the types of 
structure that it can interconnect, it may damage the flexible circuit 
board. 
U.S. Pat. Nos. 4,252,389 to Olsson B. E., and 4,334,728 to Reynolds C. E. 
et al., however, both relate to zero insertion force connectors and are 
essentially non-damaging. In each case, a clamp carried by the rigid 
structure is used to exert wiping pressure on the idle side of a flexible 
conductive film placed between it and the rigid structure. These kinds of 
arrangement have several undesirable features including an unavoidable 
dependence on the accuracy of the user and the need for the clamp, in 
toto, to be carried by the rigid structure. In addition, the application 
of such an arrangement is essentially limited. 
The present invention seeks to provide a connector mechanism that is 
non-damaging, of general application, is capable, at least in an extended 
form, of tolerating less than accurate handling by the user and will 
ensure positive electrical coupling of compatible structure and conducting 
line combinations. 
According to one aspect of the present invention, there is provided a 
connector mechanism releasably electrically interconnecting two 
structures, each said structure carrying conducting lines, said connector 
mechanism comprising common actuator means; fixed contact means, said 
fixed contact means being mounted on one of said structures, electrically 
connected to said conducting lines on said one of said structures and 
fixed relative to said one of said structures; flexible conductive film, 
said flexible conductive film forming part of the other of said structures 
and accommodating at least one extension of said conducting lines thereof; 
floating contact means, said floating contact means being an electrically 
integral part of said flexible conductive film, carried by said common 
actuator means and free to move both toward and away from said fixed 
contact means as well as across said fixed contact means, as independent 
motions, under the control of said common actuator means, while said 
structures are maintained in an engaged juxtaposition. 
According to another aspect of the present invention, there is provided a 
connector mechanism for electrically connecting a first and second 
structure, each of which carries conducting lines, comprising fixed 
contact means provided on said first structure and electrically connected 
to the conducting lines carried by said first structure, flexible film 
means provided with conducting lines, said conducting lines on said film 
being electrically connected at one end of said film means to the 
conducting lines carried by said second structure, floating contact means 
provided on said flexible film means, said conducting lines on said film 
means being electrically connected at the other end of said film means to 
said floating contact means, and actuator means associated with said film 
means for moving said floating contact means both toward and away from 
said fixed contact means and across the fixed contact means, as 
independent motions, while said structures are maintained in an engaged 
juxtaposition. 
As described hereinafter, a connector mechanism according to the present 
invention, for electrically connecting two structures carrying conducting 
lines, comprises fixed contacts on one of the structures and floating 
contacts on the other of the structures, the floating contacts being free 
to move towards and away from the fixed contacts and across the fixed 
contacts as independent motions, under the control of a common actuator 
each floating contact being an electrically integral part, carried by the 
actuator, of a flexible conductive film. 
The provision of a shroud on the fixed contact structure carrying markings 
registered with the fixed contacts and engaging the actuator provides 
coarse location, while the flexibility of the web and the mounting of the 
floating contacts on a resilient pad, on a carriage provided with cam 
followers riding on a multi-throw linear cam permits independent locating 
and wiping motions, independently of each other and at selected pressures, 
including, of course, zero pressure on insertion making the connector 
mechanism an effective ZIF connector. 
The present invention will be described further, by way of example, with 
reference to embodiments thereof, as illustrated in the accompanying 
drawings.

FIGS. 1 and 2 show one complete connector mechanism 20 and a plurality of 
partial connector mechanisms according to the present invention. Some 
component parts are detailed on the complete connector mechanism, which is 
located in the positive octant delineated by the co-ordinate axes shown in 
FIG. 1, and some on the partial mechanisms for clarity since they are 
located on surfaces of the complete mechanism that are obscured. The 
single connector mechanism electrically connects two structures 22, 24 
carrying conducting lines 26, comprises fixed contacts 28 on structure 22, 
and floating contacts 30 on structure 24, the floating contacts being free 
to move towards and away from the fixed contacts and across the fixed 
contacts as independent motions, under the control of a common actuator 
32, each floating contact being an electrically integral part, carried by 
the actuator, of a flexible conductive film 34. The film (see FIG. 4) is 
formed of alternate layers of conductive and non-conductive material, so 
that at least some of the conductive material forms a transmission line 
structure, and the film is provided with apertures 44 to enhance its 
flexibility. 
The common actuator is a compound camming mechanism, able to produce time 
separated motion in different directions (as illustrated in FIG. 3) in a 
single actuation, the floating contacts being carried by a resilient 
interposer 38, fixed to a carriage 50 which carries cam followers 54A and 
54B engaging a linear cam 52. 
When the connector mechanism 20 is assembled into the configuration shown 
in FIG. 1 by bringing together the two structures 22, 24, by relative 
motion in the ZZ direction, a single pass of the linear cam 52 produces 
the following main sequence of time separated relative movements: 
motion of the floating contacts 30 toward the fixed contacts 28 in XX 
direction until the floating contacts 30 just touch the fixed contacts 28, 
followed by attempted motion of the floating contacts 30 toward the fixed 
contacts 28 such that distortion of the resilient interposer 38 applies a 
pressure between the fixed contacts 28 and floating contacts 30; 
motion of the floating contacts 30 across the fixed contacts 28 in YY 
direction; 
motion of the floating contacts 30 substantially retracing at least part of 
the previous path across the fixed contacts in the YY direction; and 
attempted further motion of the floating contacts 30 towards the fixed 
contacts 28 further increasing the pressure between the fixed and floating 
contacts 28, 30. 
The fixed contact structure 22 of the two structures shown in FIGS. 1 and 2 
carries a rigidly attached shroud 46. The shroud 46 locates the cam in the 
XX and YY directions with respect to the fixed contacts on initial 
assembly of the connector mechanism and carries locating markings 48A, 48B 
which are registered with the fixed contacts. When the actuator 32 is 
initially actuated, by means of a handle (not shown), the carriage 50 is 
moved, in the YY direction, into engagement with the locating markings 48B 
of the shroud 46, locating the carriage in the ZZ direction. 
The initial and terminal phases of the actuator 32 operation are relatively 
idle, and resetting of the actuator 32 returns the floating contacts 30 to 
their starting positions, retracing the listed motions in reverse order. 
As already indicated, there is a connector mechanism 20 on each side of 
card 22, and the two connector mechanisms are loosely coupled, as by 
member 64 (see FIG. 6). 
DETAILED DESCRIPTION OF THE EMBODIMENTS 
Returning to the embodiments illustrated in FIGS. 1 to 5 of the drawings 
and considering them in greater detail, structure 22 is a printed circuit 
card, of which only a corner is shown, and has conducting lines 26 on both 
faces thereof, each set of conducting lines ending in a 4.times.N array of 
contact dimples 28, fixed relative to the card. The conducting lines 26 
are only hinted at, rather than being shown accurately in FIGS. 1 and 2 
and no attempt has been made to show their connection to the contact 
dimples 28. In any case, much of the conducting line configuration will be 
buried in most applications. Shroud 46 overhangs the contact dimple array 
and is formed of two substantially equal mutually perpendicular extents 
46A and 46B. Extent 46A is perpendicular to the face of the card from 
which it extends and parallel to the card edge and the N-dimension of the 
contact array. Extent 46B extends parallel to the card face beyond the 
card edge and has a T-cross-section groove 48A let into its inner surface 
facing the contact array. Extent 46B has notches 46B let into its exposed 
edge. Selected surfaces of the groove and notches are accurately 
registered with the contact array and act as locating markings. 
Linear cam 52 has an integral longitudinal rail 52A which fits into the 
groove 48A in the shroud and aligns the pass direction of the linear cam 
relative to the fixed contact array in the ZZ direction. The cam 52 has 
multiple pairs of camming surfaces providing throws in both the XX and the 
YY directions but these are arranged, relative to the cam followers 54A 
and 54B, so that the currently effective throw is either entirely in the 
XX direction or entirely in the YY direction. The effect of these throws 
for a single pass of the linear cam is illustrated in FIG. 3. 
In addition to fitting in the groove 48A in the shroud, the linear cam 52 
also fits into the carriage 50 which is a generally rectangular channel, 
open at the ends for access in the ZZ direction and having walls extending 
in the XX direction. Eight cam followers are located in the inner surfaces 
of the carriage channel. The four followers 54A cooperate with the cam to 
move the carriage in the YY direction, while the four followers 54B 
cooperate with the cam to move the carriage in the XX direction. It is 
pointed out that the recited relative orientation of the component parts 
holds for the connector mechanisms when assembled. Clearly, since each 
mechanism can be dis-assembled and handled in isolation there is no 
absolute significance in the recited orientations. The object of the 
exercise is to locate the cam in the shroud and, by moving the cam in the 
carriage in the ZZ direction, move the carriage in both the XX direction 
and the YY direction while keeping these motions quite separate. 
The base of the carriage channel thus aligns with extent 46B of the shroud 
and resilient interposer 38 is fixed to the exposed surface of the base. 
The end of flexible film 34 that carries the floating contacts 30, hidden 
for the full mechanism in the positive octant but shown for the opposed 
partially illustrated mechanism, is fixed to the exposed surface of the 
interposer with the floating contacts, in a 4.times.N array conforming to 
the fixed contact array, exposed and aligned with the carriage as the 
fixed contact array is aligned with the shroud. The floating contacts 30 
are flat and square and the intention is to center one fixed contact 
dimple 28 on each floating contact flat 30, assuming a fully active array. 
The film 34 passes under the carriage and is locked under a guide rail 70 
fixed to a mother board 72, the conducting lines 26 in the film being 
electrically coupled to the mother board conducting lines (not shown). 
Thus, a single basic floating contact structure in this arrangement 
comprises the cam 52, the carriage 50, the interposer 38, the film 34, the 
guide rail 70 and the mother board 72 (although a plurality of connector 
mechanisms are indicated in FIGS. 1 and 2 and certain component elements 
are shared). 
The cam and carriage combination is connected to the mother board by the 
film 34, the inherent flexibility of which is enhanced by the longitudinal 
apertures 44 therein, but the combination can move relatively freely away 
from and across the mother board due to the film's flexibility and also 
due to a certain amount of film length which is surplus to minimal 
requirements. This freedom of movement of the combination is necessary to 
permit interlocking of the actuator, shroud and guide rail to establish 
registration in a manner to be described and to permit the cam driven 
motion sequence of the floating contacts. The connector mechanisms of this 
invention are designed to be electrical connectors not physical locking 
mechanisms. They permit the card structures to be assembled and held 
mechanically together, without the need for registration to a degree of 
precision equivalent to the contact pitch, since the the fine adjustment 
is internal, using the slack in the film. 
Interlocking of the component elements is partly a function of the 
engagement of the cam rail 52A in the groove 48A and partly a function of 
the engagement of a pair of lugs 55 extending outwardly and downwardly 
from the lower wall of the carriage, in the notches 48B in the shroud, as 
well as in a corresponding pair of cut-aways 73 in the guide rail. 
The lugs essentially remain engaged in the cut-aways but, being of smaller 
dimensions, can move within the cut-aways in all three indicated 
directions, and, in particular, can move downwardly in the YY direction by 
at least the depth of the notches 48B without impacting the film 34. If 
one considers the rail of the cam to be fixed in the YY direction relative 
to the mother board, which is effectively correct in all operative 
conditions, and the cam to be fully retracted, the cam maintains the 
carriage depressed sufficiently in the YY direction for the bottom of the 
shroud, when sliding forwardly in the ZZ direction with the cam rail 
engaged in the shroud groove, to clear the tops of the lugs. In this way, 
the notches 48B can be brought into position over the lugs. Also, during 
such initial engagement, other surfaces of the cam maintain the carriage, 
and hence the floating contacts, clear of the fixed contacts on the card. 
From the point of view of establishing electrical contact connection, the 
camming mechanism is idle and the conceptual conditions indicated at the 
origins in the graphs of FIG. 3 obtain. During initial engagement, there 
is no relative movement of the cam with respect to the carriage. 
To establish electrical contact connection, the cam is pulled steadily in 
the ZZ direction for a fixed distance, moving the carriage alternately in 
the YY direction and in the XX direction relative to the shroud and hence 
correspondingly moving or attempting to move the floating contacts 
relative to the fixed contacts. This activity is illustrated to the right 
of the origins in FIG. 3. As the cam moves in the Z.sub.2 direction from 
its retracted position corresponding to the origin in FIG. 3 to a position 
indicated by Z.sub.1, the carriage is raised in the YY direction relative 
to the shroud, moving the lugs upwardly in the YY direction into the 
notches 48B. The notches have tapered sides and serve to register the 
carriage with the shroud in the ZZ direction, consequently, similarly 
registering the contacts in the ZZ direction. 
The next part of the action of the cam as it moves from Z.sub.1 to Z.sub.3 
is to move the carriage away from the shroud toward the card in the XX 
direction and, at some point of the cam movement indicated as Z.sub.2, the 
contacts will touch and the resilient interposer 38 will begin to 
compress. At this point, actual pressure between the contacts begins to 
build, as indicated in the middle graph in FIG. 3. Inter-contact pressure 
builds due to compression of the interposer until, at Z.sub.3, the cam 
ceases to drive the carriage in the XX direction and starts to drive the 
carriage first upwardly and then partially back again in the YY direction. 
This action, corresponding to travel of the cam from Z.sub.3 to Z.sub.4, 
produces wiping and backwiping of the floating contacts over the fixed 
contacts at constant inter-contact pressure. Thereafter, the cam, 
travelling from Z.sub.4 to Z.sub.5, ceases to drive the carriage in the YY 
direction and continues driving the carriage away from the shroud in the 
XX direction, increasing the compression of the interposer and the 
inter-contact pressure. Thereafter, the cam becomes idle, maintaining the 
status quo until movement of the cam ceases, electrical contact having 
been finally established at Z.sub.5. 
It is pointed out that, with the described arrangement, the card contacts 
are well protected. During engagement, with the cam "retracted", it is not 
possible to both engage the cam rail with the shroud groove and have even 
accidental contact collision. During wipe, the inter-contact pressure is 
controlled and constant, to produce adequate wiping action with minimum 
wear. 
The film structure is illustrated in FIG. 4 which concentrates on the end 
of the film 34 which incorporates the floating contacts 30. The film 
comprises a sandwich of five layers 30 and 26, 42, 40, 42, 26 which are 
shown partially separated but which are, in fact, bonded together. Layers 
42 are of nonconductive polymer and enclose conductive layer 40 which, 
apart from an array of apertures 41 corresponding to the contact array and 
the slots 44, is a continuous layer comprising a ground plane. The two 
outer layers are conductive and define the floating contacts 30 and the 
individual conductive paths thereto. Because a dense contact array is 
desired, only two rows of contacts 30 connect directly to conductive paths 
26 provided on the same (upper) exposed surface as is occupied by the 
contacts. The other two rows of contacts 30 connect, through conductive 
vias 31 in the film, to respective conductive paths provided on the other 
(lower) exposed surface. 
As already indicated, the basic connector mechanism connects to one area of 
one side of the card. As hinted at in FIGS. 1 and 2, one would reasonably 
expect to require connector mechanisms on both sides of a card and, for a 
card of significant edge length, plural films, interposers (which may be 
springs) and carriages, per side. In this latter case, the cam and shroud, 
on each side of the card, can be common to all the connector mechanisms of 
the respective side and it is recommended that, with connector mechanisms 
on both sides of the card, the cams are loosely inter-connected as 
illustrated in FIG. 6 by a coupling yoke 64. 
As the cam is pushed toward its retracted position, the illustrated 
connector mechanism will repeat the described sequence of operations, but 
in the reverse order, leaving the card and shroud free to be disengaged by 
being slid backwardly in the ZZ direction. It is possible, however, by use 
of a differently constructed cam to alter the sequence of relative motions 
on retraction the cam so that the first action is complete separation of 
the contacts in the XX direction, followed by direct passage of the 
carriage to the point at which the carriage is depressed sufficiently to 
disengage the lugs from the notches 48B. 
As opposed to the specific arrangement shown in the drawings, the part 60 
of the film 34 remote from the floating contacts 30 may be connected to: 
(a) the floating contacts 30 of a similar connector mechanism 20, so that 
the conducting lines of the floating contact structure, in each case, are 
merely those of the flexible web; or 
(b) a fixed structure, such as a housing, or to a movable structure which 
need be neither accurately registered with respect to the fixed contacts 
28, nor even close thereto.