US 3609463 A
Description (OCR text may contain errors)
References Cited UNITED STATES PATENTS 6/1929 Coldwell ...339/176 MP UX ...339/176 MP UX .....339/17 LM UX 3/1965 James..,........................339/17 LM UX 339/l76 MP UX 1,718,529 2,857,577 10/1958 Vanderpool... 3,129,990 4/1964 Rice et al....... 3,173,732
FOREIGN PATENTS 1,001,569 8/1965 Great Britain.............
Primary Examiner-David Smith, Jr. Att0rneyBaldwin, Wight & Brown ABSTRACT: An arrangement for connecting circuits of printed-circuit cards to circuits of a connection panel, comprising connectors fixed in parallel relationship to one another on said connection panel, each connector being provided with contact blades of which one end is soldered to a conductive surface of the connection panel and each of which is arranged to be pressed against a contact surface on a card inserted between two connector elements, under the action of an insulating push member pushed by a spring independent of the contact blade.
1102b 1/02, H05k 1/04 317/101 17 LC, 17 M Bernard Andre Laboue Goussainville, France Appl. No. 859,748  Filed Sept. 22, 1969 Patented Sept. 28, 1971 Assignee Societe Industriclle Bull-General Electric,
(Societe Anonyme) Paris, France Oct. 1, 1968 France 168305  CONNECTORS FOR PRINTED-CIRCUIT CARDS 7 Claims, 8 Drawing Figs.
DH, 101, 101 CC; 339/176 MP, 17 LM United States Patent  Inventor  Priority  FieldofSearch...,.......................................,
PATENTEDSEP28|971 SHEET 1 BF 3 C $711. a l
V Ga v- Hill nu I] I MIM I l/I /KP I l t I III b Mafia PATEHTEH SEP28 sum 3 OF 3 CONNECTORS FOR PRINTED-CIRCUIT CARDS The presentinvention relates to improvements in connectors for printed-circuit cards and concerns an arrangement which is more particularly adapted for electrically connecting the conductors of printed-circuit cards to conductors of a connection panel also comprising printed circuits. These electrical connections are made by means of connectors, regarding which a major problem exists at present, namely to minimize the length of the conductors introduced by the said connector into the circuits in order not to insert into the said circuits conductors having electrical characteristics which are likely to modify substantially the electrical characteristics of the connected circuits, sometimes with the introduction of inductive couplings or stray capacitances between the circuits.
The techniques at present employed for the production of compact circuits make it possible to reduce considerably the overall dimensions of the greater part of the electrical circuits present in information-processing and other equipment. These compact circuits are often made in the form of so-called printed circuits," which are sometimes assembled in a number of layers in detachable cards and in connection panels designed to support connectors and to make the connections between the circuits of different cards. Connecting devices are necessarily employed for establishing the electrical connections between the circuits of the cards and the circuits of the vpanels. In these connectors, a very large number of contact members are assembled within a very small space. Many connector systems are known in which the contact members by which the electrical connections are made are formed of relatively long flexible conductive blades or rods which are often bent over on themselves and which are adapted to supply by their own resilience a sufficient bearing force on the contact surfaces. When connectors are employed to connect together circuits through which there pass electric pulses having components of very high frequency, those parts of the connectors through which these pulses pass often have the disadvantage that they introduce discontinuity of impedance matching and the looped forms of some of the parts of these circuits often give rise to stray inductive couplings between circuits. The present invention has for its object to obviate these disadvantages and relates to an arrangement in which electrical connections are made by means of connectors in which the conductive parts by which circuits are connected are of remarkably small length and in which the conductive surfaces by which the said contacts are made are each subjected at a number of points to a mechanical pressure which is exerted on these surfaces by means of mechanical members independent of the electrical circuits. In the case envisaged in which the conductors of the printed circuits of the detachable cards and of the connection panel are comparable to portions of transmission lines whose characteristic impedance is predetermined, another object of the invention is to provide a connector, as defined above, in which the length of a conductive member capable of locally exhibiting a different characteristic impedance is so small that the resultant disadvantages are negligible or zero.
The invention concerns an arrangement for connecting circuits of printed-circuit cards to circuits of a printed-circuit connection panel which supports a plurality of connectors disposed in parallel relationship to one another at such a distance as to enable a card to be inserted between two consecutive connectors and to enable it to be maintained perpendicularly to the said panel, wherein each connector is characterized in that it comprises at least on one side corresponding to one face of a card provided with contact surfaces, a row of conductive and flexible contact blades, one portion of each of which is soldered to a conductive surface on the connection panel, while another portion thereof is situated against a contact surface on the card, a row of push members, each of which is arranged to be slidable in a recess situated opposite a contact blade, and a row of springs, each of which is arranged to urge a push member against a contact blade and to urge the latter against a corresponding contact surface on the card.
An arrangement comprising such connectors makes it possible to produce an assembly of extremely compact circuits in which the contacts between circuits are made with maximum reliability, with the introduction of minimum disturbance into the electrical characteristics of the circuits.
Further advantages and features of the invention will become more readily apparent in the course of the following description, with reference to the accompanying drawings, in which:
FIG. 1 is a sectional view of a part of an arrangement of connectors according to a first embodiment of the invention, this section being taken along the line 1-1 of FIG. 2,
FIG. 2 is a plan view of a part of the same arrangement as seen along the line 22 of H6. 1,
FIG. 3 is a plan view of a portion of a connection panel as seen along the line 3-3 of FIG. 1,
FIG. 4 illustrates a second form of construction of an arrangement of connectors as seen along the line 44 of FIG. 5.
FIG. 5 is a view in section along the line 5-5 of FIG. 4,
HO. 6 is an external view of a portion of a printed-circuit card as seen in the direction 6 of FlG. 1, showing an arrangement of the contact surfaces on the card,
F IG. 7 is a fragmentary sectional view constituting a variant of FIG. 4, and
FlG. 8 is a view in perspective of various parts of a connector of the type illustrated in FIGS. 4 and 5.
FIG. 1 shows a portion of an arrangement in which three connectors A, B and C respectively are mounted on a printedcircuit connection panel ll, the said three connectors being shown in section along the line 1-1 of FIG. 2. The connectors of one assembly are identical in principle and the connectors A and C of FIG. 1 are only partly shown. A printed-circuit card CA] is shown inserted between the connectors A and B and a second card CA2 is shown in the preparatory position for insertion, in which it is only engaged in guide means 12 arranged in known manner at the ends of the connectors (see also HO. 8) in order to ensure correct engagement of the cards between the connectors. The connectors A, B and C are fixedly mounted on the connection panel H, for example by means of pins 14 situated at intervals along each connector so as to secure the latter on the connection panel in parallel relationship to other connectors and to maintain them at a distance X (FIGS. 1 and 4) which is determined in accordance with the thickness of the cards which are to be inserted between the said connectors. A connector of like form may be employed in assemblies designed to receive cards of different thicknesses, in accordance with the distance X between the points at which the connectors are secured to the connection panel. in the arrangement illustrated in fragmentary form in FlGS. l and 2, each connector comprises an insulating body 15 provided with a base 16, a central partition 17 and lefthand and right-hand lateral walls 18 and 19 respectively, which are connected to a central partition by ribs 20 disposed on either side of the said partition. The lateral walls are formed with left-hand and right-hand recesses 22 and 21 respectively, which are each situated between two ribs and each adapted to receive a push member 23 consisting of insulating material, which is freely slidable in a recess. Each push member is provided, towards the exterior of the connector, with two bosses 24 and 25 and provided within the connector with two shoulders 26 and 27 arranged to prevent the push member from leaving the connector. The push members disposed on one side of a connector may be connected together by means of a flexible strip 28 adapted to permit relative independence of the displacements of each push member in its recess. These strips, which merely have the object of facilitating the positioning of the push members on one side of a connector, are not absolutely necessary for the correct operation of the device. A spring element comprises a metal strip 29, which bears against the central partition 17 and is provided, on each side, with flexible blades 30 and 3| on the left-hand and right-hand sides respectively, which are adapted to form leaf springs and are each engaged between two ribs on the insulating body of the connector, that is to say, opposite a corresponding push member, in order to push the latter towards the outside of the connector. The metal strip 29 is maintained in position between the central partition of the connector and a cover 32 of flexible plastics. The said cover is maintained in position on the body of the connector by means of two longitudinal strips 33 and 34 adapted to engage in grooves 35 and 36 extending along the lateral walls 18 and 19 of the body of the connector. The connection panel 11 may, like the printed-circuit cards, comprise a number of layers of printed circuits assembled in the thickness of one panel, which is provided (FIG. 3) on its upper face with conductive surfaces situated in rows 37 and 38 to the left and to the right respectively, for each connector and connected to electrical circuits of the panel. These conductive surfaces are positioned so that they may each receive by soldering, by an appropriate method, the lower end of a conductive blade 40 to the left or 41 to the right, of which the other end is engaged in a slot 42 or 43 in the upper part of each of the lateral walls and in which it is retained by a barlike portion 44 adapted to engage in the said slot. Provided on each side of the slots are bosses 45-46 which are arranged to center the cover 32 on the connector.
Each contact blade extends past the bosses 24-25 of a push member.
In order to facilitate the fitting of the contact blades on one side of a connector, these blades may be connected together, before fitting, at their upper end by means of a strip of insulating plastics (not shown). In FIG. 1, a contact blade 41A belonging to the right-hand row of the connector B is soldered at its lower end to a conductive surface 38A of the row 38 (FIG, 3) of the connection panel. The said blade extends past the bosses 24 and of a push member 23 and the upper end of this blade is retained in one of the slots 43 in the partition 19. When no card has been inserted between two connectors (for example B and C in FIG. 1), the contact blades ofone row and the blades which are in the connector disposed opposite thereto are tensioned under the action of the springs and 31 of each connector, acting on the push members, this tension being limited by virtue of the fact that the shoulders 26 and 27 of the push members abut (FIG. 1) the inside face ofa lateral wall of the connector. In addition, the contact blades to the left of the connector B (FIGS. 1 and 2) are urged towards the connector by the card CA1 which has been inserted between the connectors A and B. In this case, each contact blade of the same row is urged by its push member against a corresponding contact surface of the card CA1. Thus, all the contact blades 41 situated in the right-hand row of the connector A are also applied under the same conditions against the contact surfaces of the card CA1. FIG. 6 shows the form and the relative arrangement of the contact surfaces 51 on a portion of the printed-circuit card CA2 as seen in the direction of the arrow 6 of FIG. 1. When the printed-circuit card CA1 is introduced between the connectors A and B, the contact blades and the corresponding push members are pushed towards the inside of the bodies of the connectors and the contact blades may be carried slightly downwards by the friction of the introduced card, but the said blades are retained in the upper part of each connector by the blade portion which is engaged in a slot. Each push member receives the thrust of its corresponding spring at a point situated substantially on the axis of the said push member. This thrust is transmitted by the two bosses of the push member at two points of the contact blade, which are situated symmetrically about the said axis. Consequently, the thrust exerted by the spring is substantially equally distributed among the bosses of the push member at two points of the contact blade bearing on a contact surface of a card, whereby perfect electrical contact is ensured at least at these two points. It is known that the friction of the contact surfaces on the contact blades of the connectors when a card is introduced contributes to cleaning the contact surfaces and to improving the electrical contacts.
FIGS. 4, 5 and 8 show another embodiment of the invention in an arrangement illustrated in section in FIGS. 4 and 5,
which show three connectors D, E and F mounted on a connection panel 11 similar to that of FIG. 1 by means of pins fitted on the one hand into the connectors and on the other hand into the said connection panel. Each connector comprises an insulating body having a central partition 62 extending along the length of the connector, an upper partition 63 and lateral walls 64 and 65 to the left and to the right respectively, which are connected to the central partition by ribs 66 and 67 and formed with recesses 68 and 69 to the left and to the right respectively for push members 70 similar to the push members 23 of FIGS. 1 and 2. The push members are subject to the action of springs 72 and 73, which are also connected to a central strip 74. It will be noted that in this case the arrangement of the insulating body of the connectors D, E and F corresponds to an inverted arrangement of the connectors A, B and C. In the connectors D, E and F, the contact blades are either formed of thin metal strips 75 and 76 disposed in parallel relationship and adhesively bonded by an appropriate method to the outside face of a thin insulating support sheet 77, or formed by deposition of conductive metal layers in the form of parallel bands. The insulating strip provided with conductive bands is appropriately positioned on the upper face of the connection panel, whereafter the horizontal portions of the contact blades are welded by any appropriate method to the corresponding conductive surfaces of the connection panel. Thereafter, the body of the connector provided with its push members and springs is positioned on the said panel and held in position thereon by pins 60. The two edges of the support sheet 77 are thereafter raised and bent down on to the body of the connector, on which they are maintained when a plate 78 is thereafter secured by pins 79 extending through holes appropriately positioned in the plate 78, in the two edges of the insulating sheet 77 and in the body of the connector. By reason of the depression formed in the partition 63, a slight tension is obtained in the insulating sheet, this tension being sufficient to cause the latter to adapt itself to the bosses of the push members, without the latter being moved into their recesses. In FIG. 4, a printed-circuit card CA3 is provided on its two faces with components 54-55 which may form functional units such as amplifier devices, switching circuit or the like, of which the maximum overall dimensions are indicated by a dash-dotted line 58. A similar arrangement may be provided on the cards CA l-CAZ which are employed with connectors A, B and C, in FIGS. 1 and 2. In most cases, the connectors are provided at their ends with plates 80-81 formed with guide grooves 12 and 13 (FIGS. 1, 4 and 8) which are adapted to guide the cards on their insertion into the conncc tors.
In the examples illustrated in FIG. 1 to 5, the distance X between the axes of two neighboring connectors is about 18 millimeters in the cases described. On the other hand, the spacing between the contact blades may be equal to or less than 2.54 mm. Assuming in the least favorable case, that a correct electrical contact is ensured, between a contact blade and the corresponding contact surface of a card, only at the level of the upper boss of the push member acting on this blade, the contact blade length which will be comprised between this contact point and the soldering point of the said contact blade on a conductive surface of the connection panel, i.e. the contact blade length constituting a discontinuity in the impedance matching, will not exceed 8 mm., which is a remarkably short length as compared with the length introduced by the majority of known connectors.
FIG. 7 illustrates a cutoff portion of a connector G similar to those shown in FIGS. 4, 5 and 8, but specially designed to introduce no interruption of impedance matching between the connected printed circuits. The construction is generally similar to the preceding one, but in this embodiment a flexible insulating sheet is provided on its outside face with contact blades 91 adhesively secured or formed as already stated by a thin conductive metallic deposit, but in addition the insulating sheet is provided on its inside face with a conductive deposit 49 forming an earth surface and connected to an earth conductor of the connection panel 11. This connection may be obtained by means of one or more pins 94 also serving to secure the connector to the connection panel.
With due regard to the dielectric constant of the material of the insulating sheet, to its thickness and to the dimensions of the contact blades, it is possible to arrange that the characteristic impedance of the transmission line formed by each contact blade is equal to the characteristic impedance adopted for the printed circuits of the detachable cards and of the connection panel. There is therefore no longer any mismatch caused by the members of the connector.
It will be noted that in FIG. 6 the contact surfaces on the opposite faces of one and the same card are alternately arranged, that is to say, the contact surfaces of one face are offset by one-half spacing in relation to the contact areas of the opposite face of the card. Consequently, those contact blades of the faces of two connectors which are provided for the two faces of one and the same card are necessarily (FIGS. 2 and 5) arranged alternately for these two faces. In the examples described in the foregoing, the contact blades are alternately arranged on either side of the axis of each connector and the contact surfaces 37 and 38 are alternately positioned on the connection panel 11 to receive the contact blades of one connector. This staggering of the contact blades of the opposite rows of a connector is not the only possible arrangement, because a similar result can be obtained with connectors of symmetrical construction by longitudinally staggering by a half-pitch in relation to one another the neighboring connectors on the connection panel.
It is obvious that the embodiments and adaptations which have been described to illustrate the invention have no limiting character and that any modifications and adaptations may be made to the arrangements described in accordance with the circumstances and the applications without departing from the invention.
l. A connecting system for detachably connecting conductive surfaces aligned on the faces ofa number N of printed-circuit cards with a conductive surfaces on a printed-circuit panel, said system comprising:
a number Nj-l of connector elements fixed parallel to said panel in order to permit the insertion of an edge of one of said cards between two adjacent connector elements, each of said elements comprising:
an elongated body of insulating material having two lateral walls, each lateral wall being formed with a plurality of recesses a push member slidably disposed in each of said recesses, said push member consisting of insulating material and being provided with bosses,
a spring element fixed in said body and provided with two sets of spring blades, each of said spring blades being disposed to urge one of said push members through the corresponding recess in order that the bosses of said push member may project outside of the associated lateral wall, and
two series of elongated contact blades, each of said blades having one end thereof bonded to a conductive surface on said panel between the latter and an opposed connector body and having a central portion disposed opposite to an associated one of said push members whereby said central portion is urged towards a conductive surface on a printed-circuit card when the latter is inserted between and the corresponding connector bod and has its two edges turned down one upon the other and ixed on said connector body.
4. A connecting system according to claim 3, wherein each of said sheets consists of a material resistant to the tin-soldering temperature, such as polyethylene terephthalate.
5. A connecting arrangement for detachably connecting a plurality of conductive surfaces, disposed on at least one face of a circuit board and spaced apart along one edge of said face, to conductive surfaces disposed on one face of a connection panel, said connecting arrangement being provided with at least one connector element comprising:
an elongated connector body of insulating material mounted on said one face of said connection panel, the elongated dimension of said body being oriented parallel to the plane of said one face of said connection panel and a lateral wall of said body extending along the length thereof being tangent to a plane perpendicular to the plane of said one face of said connection panel, said wall being provided with a plurality of apertures extending therethrough,
a push member slidably disposed in each of said apertures.
a spring member mounted in said body for each of said push members, each of said spring members being disposed to urge the associated push member through the corresponding aperture to project outwardly from said lateral wall, and
a plurality of elongated contact strips spaced apart along the length of said lateral wall and oriented transversely to the length of said lateral wall, each of said strips having one end thereof bonded to one of said conductive surfaces disposed on said one face of said connection panel between said panel and said connector body, having a central portion thereof disposed opposite to a respective one of said push members to provide for said control portion to be urged away from said wall by the corresponding push member, and having the other end thereof affixed to said body near the edge of said lateral wall remote from said panel.
6. The arrangement of claim 5 provided with a plurality of said connector elements, the respective connector bodies of said connector elements being oriented mutually parallel and spaced apart to admit the edge of one of said circuit boards between adjacent pairs of said bodies.
7. The arrangement of claim 5 for detachably connecting a plurality of said conductive surfaces'disposed on both faces of a circuit board to conductive surfaces on said panel and provided with a pair of said connector elements, the respective connector bodies of said connector elements being oriented mutually parallel and with the respective lateral walls of said bodies facing each other, said connector bodies being spaced apart to admit the edge of one of said circuit boards between said facing lateral walls.