US 3264599 A
Description (OCR text may contain errors)
R. J. KINKAID CONNECTOR BLOCK ASSEMBLY Aug. 2, 1966 2 Sheets-Sheet 1 Original Filed Nov. 27.
Aug, 2, 1966 R. J. KlNKAlD CONNECTOR BLOCK ASSEMBLY Original Filed Nov. 27, 1961 2 Sheets-Sheet a INVENTOR. ROBERT J. KmKmo Biflflp MW United States Patent 3,264,599 CONNECTOR BLOCK ASSEMBLY Robert John Kinkaid, New Cumberland, Pa., assignor to AMP Incorporated, Harrisburg, Pa.
Original application Nov. 27, 1961, Ser. No. 157,037. Divided and this application Mar. 3, 1965, Ser. No. 436,827
3 Claims. (Cl. 339-17) This application is a division of my parent application, Serial No. 157,037, filed November 27, 1961, now Patent No. 3,215,975 which is a continuation-in-part of my prior application, Serial No. 75,955, filed December 15, 1960, now abandoned. This invention relates, in general, to a connector block assembly for wiring electrical systems, particularly for a system including banks or arrays of printed circuit boards or cards.
A variety of connectors have been proposed for incorporating banks of printed circuit cards in a system, but the lack of versatility, reliability, ruggedness and economy, in more or less degree, is a common failing.
An important feature of the invention, therefore, is the provision of a rugged and reliable connector assembly easily adaptable to a variety of functions and forms in the wiring of printed circuit card banks in electrical systems. To this end, as an objective the connector assembly of this invention includes a multi-contact plug block anda mating socket block, wherein the plug block may be formed so as to connect a printed circuit card individually into one of an array of socket blocks, or additionally may provide connections for two or more socket blocks to a single printed circuit card, or merely to provide feed-through connections for two or more socket blocks.
Another feature of the invention concerns the character of the contacts in the plug and socket blocks which are simple and rugged, yet are producible with a wide range of manufacturing tolerances. Another feature lies in the preservation of long life of the contacts by providing a slide-fit engagement which is highly wear-resistant. Closely allied with this feature lies the reliability of contact engagement by multiplicity of contact points between the contacts of the plug and socket blocks, and between the plug contacts and the printed circuit cards.
An additional feature resides in the provision of a commercially feasible organization of parts which overcomes certain disadvantages inherent in the structures of the prior art, which features will become apparent to those skilled in the art upon reading the following detailed description when taken in conjunction with the drawings in which:
FIGURE 1 is a perspective view of an embodiment of a connector block assembly according to the present invention;
FIGURE 2 is an enlarged side view, in section, of the connector assembly of FIGURE 1, but with the connector blocks engaged;
FIGURE 3 is a fragmentary sectional view taken along lines 33 of FIGURE 2;
FIGURE 4 is a fragmentary sectional view, further enlarged, taken along lines 4--4 of FIGURE 2;
FIGURE 5 is an enlarged perspective view of a contact for insertion in the socket block of the assembly;
FIGURE 6 is a sectional perspective view illustrating a modified form of a connector block assembly of the invention;
FIGURE 7 is a sectional perspective view illustrating another modified form of the plug block; and
FIGURE 8 is a sectional perspective view of another embodiment of a plug block of the invention.
With reference to the embodiment of the invention, as shown in FIGURES 1-5, the connector block assembly 3,264,599 Patented August 2, 1966 includes a plug block 2 mounted on a printed circuit card 4 for cooperation with a socket block 6 to complete circuit connections from the printed circuit lines 8 and the electrical components (not shown) on card 4 to lead wires 10 associated with socket block 6 which lead to other apparatus of the electrical system involved.
The body of plug block 2 is of suitable insulating material and carries a row of plug contacts 12 which preferably are sheet-metal stampings from brass coated with a gold plating, especially when used for dry circuit connections. Conveniently, plug contacts 12 are insert-molded in plug block 2, and to this end the main body portion 14 has a central aperture 16 through which insulation of block 2 may extend for firmly anchoring the contacts. Each plug contact has a pair of tangs 18 projecting from the bottom surface of plug block 2 and received in a pair of apertures 20 in printed circuit card 4 for solder connection 22 in the usual manner to a printed circuit line 8 that passes by the apertures. Two such tangs are preferred to protect against faulty solder connections by multiplicity. Each plug contact 12 further has a plug part projecting from the forward face of plug block 2, advantageously in the form of a generally rectangular blade 24 having smoothly rounded corners on one side to provide a pair of longitudinally extending contact surfaces 26 as best shown in FIGURE 4. Preferably, the rounded corners are achieved by coining the edges of a flat sheet metal blank, thus to maintain close tolerances. In cross-section, contact surfaces 26 are arcuate on a radius of curvature which breaks the corners of the blade to the extent of about one-half the stock thickness. The side of the blades containing the contact surfaces 26, for convenience in assembly, all face in the same direction.
Socket block 6, also preferably molded from a suitable insulating plastic material, is generally rectangular a-nd has a row of through passageways 28 extending between its front and back faces 30 and 32 respectively, thus to admit in their front end the row of plug blades 24 for cooperative engagement with a corresponding set of socket contacts 34 received into the back face of the passageways and supported in the socket block. The socket contacts also are of a form suitable for fabrication by sheet metal stamping techniques, preferably from a metal having spring qualities; e.g., Phosphor bronze with a highly conductive and corrosive-resistant coating such as a gold plating, and include an elongated bladereceiving socket section defined by a base 36 having a pair of opposed side flanges 38 bent back upon the base toward one another with their end edges 40 spaced less than the width of blades 24. Side flanges 38 additionally are curved, preferably by a coining operation to achieve close tolerances, on a radius of curvature slightly larger than the radius of curvature of plug contact surfaces 26, thus to provide mating contact surfaces 42 on their inside surfaces, the tangent at end edges 40 to this curvature projecting at a diverging angle relative to socket base 36. A radius of curvature for side flanges 38 of approximately 1 /2 times the radius of curvature of plug surfaces 26 has been found to be mechanically optimum.
As thus constructed, when a blade 24 is telescoped with a socket contact 34 and relatively pressed against side flanges 38, plug contact surfaces 26 are accommodated within the curvature of socket contact surfaces 42, effecting a predictable and constant quality of electrical engagement in their areas of meeting regardless of a wide range of configurational departures caused; for example, by accidental deformation or design tolerances. A spring prong 44 struck out of base 36 and extending inwardly and forwardly in socket contact 34 supplies the spring pressure for biasing or pressing blade 24 against flanges 38. Further, prong 44 is generally arcuate transextending inwardly and rearwardly in socket contact 34 '10 ing inwardly from a sidewall of passageway 28 as theis arranged to engage behind a stop shoulder. 47 extend forward end of the socket contact approaches lips 48 at the forward end of the passageway upon insertion of the socket contact from the back face 32. of the socket block. Stop shoulder 47 is centrally arranged on the sidewall of the passageway so that on proper insertion of a socket contact 34, it will be passed in the .space betweenend edges 40 of side flanges 38. If an attempt ismade to insert the socket contact upside down, however, base 36" will "beobstructed by stop shoulder 47, thus to assure that'all the socket contacts will be properly inserted to face in the same direction and in proper orientation relative to blade contacts 12.
At the rearward end of each socket contact; suitable means are provided for connection with lead wires .10. Typically, such means, as shown in FIGURE 5, may comprise two pairs of cars 50 and 52 jcrimped about the stripped metallic core 54 and the insulation 56, respectively, of the lead wire in a manner well-known in the art.
To interfit the. blocks simply and accurately, alignment and guide means are provided, preferably of a form adding no parts or manufacturing complexity. Thus, socket block 6 is molded with a pair of integral guide lugs 58 projecting forwardly from front face 30 along which extends a slot 60. Lugs 58 are spaced to guide an extended portion 62 of printed circuit card 4 into slot 60 as blades 12 are thereby alignedwith and enter passageways 28.
A pair of side lugs 64 for rack-mounting socket block 6 may be provided, if desired.
As thus constructed and arranged, the parts are seen to be of simple and rugged. construction, yet highly reliable and effective in performance. For example, the spring portions, viz, prong 44 and detent 46, are wholly protected by being enclosed within the channel configuration of socket contact 34. Further, it is contemplated that in normal use the solid crimp section of the socket contact, including ears 50 and 52', will have slightly larger as by being bent more or less closed, thequality of electrical c'ontactwillnot suifer so long as blade 24 is capable of entering thesocket contact'channel, since the ac V 47. pressure,will depend upon: the angle 0 between the. line tangent'to the contact point of surfaces 26and-42; and the vline along which the .force of spring 44 is applied, i.e., a line perpendicular to the base of blade 24. More specifically stated, the normal force F5, at the point ofcontact is equaLtothe. applied force, .F delivered by spring .44, divided by sin 0.= Where angle 0 is low, i.e., th contact point is low along the side .of blade 24','the normal force .can become .quite high; disadvantageously tending to-bend flanges 38 and increasing the force requiredto insert thev blade-and the wear on the parts;
during insertion, perhaps to the pointofdestruction;of any gold plating. Accordingly, it is importantthatangle 0 have .a high value; in practice. 68 have been found .to be optimum,'although angles within' the range 163 to 73 are acceptableh. 7
It is also important to. note that thefcontact. assembly is polarized; that is, blade 24 cannotbe inserted into the channel of socket contact34l iupsidedo'wn because the conimodation of curved contact surfaces 26 to contact surfaces 42 is essentially independent of the angle of flanges 38 or the relative thickness of theblade. Forceful insertionof a blade 24 is also effective to reform the flanges to operative condition. It is to be understood,
however, that in normaluselthe main bodyof socket contact 34, including side flanges 38 and base 36,- is in.
tended to be a rigid structure which does not -bend or.
deflect to any significant extent on insertion of blade 24.
That is to say, the character and control of the contact pressure between the mating parts is preferably determined primarily by-the character'and design of spring 44.1' More constant and predictable quality of electrical contact can be thus achieved;
and contact pressure between surfaces 26 and 42, it will be apparent that under the force exerted byspring 44,
blade'24 tends to wedge and bend side flanges 38 :apart. The magnitude of the wedging force, for a given spring In relation to the character ofzthe electrical-contact} unbroken or square sideicorners-of the blade would interfere with flanges 38." In other words, side :flanges 38 are turned inwardly ,sufiicient-ly far. that, relative to the width and thickness of rectangular blade 24, ithe channel of the socket. contactwill not. admit the blade but. for the breaking of side-corners 26.-
Turning nowto FIGURE 6, there is illustrated a modified form of the connector blockassembly according to the invention, wherein provision: is made? for coupling sides' terminatingin contact blades 74a, 74b and i740 projecting from opposite faces of the block; T-angs 76 for electrically and mechanically mounting a printed circuit card extend laterally from one such strip 72 through the .top ,side of the block. Similar blades,-74a ,,74b;.and-
74c, staggered to conserve center-to-center spacing of the various plug contacts 66, are arrangedrinrows for cooperationwith socket blocks 78a, 78b and 780 respectively, but it will be understood that.bus-bar 70 may be extended to providezas many rows. of contact blades ononly one. or both faces of thewplug block as required by .the conditions of a particular. use. A guidepin=80 on the plug block, there being preferably one such on each end of each row of contact blades in;cooperation with associated bores '82, serves tov align and guide ;the .socket blocks into proper interfitting relation on the plug block.
may serve merely as a feed-through connector for coupling the row of contacts: of-one socket block to the .con'-, tacts ofione. or more other socket blocks as desired,; omitting the tangs for coupling to a printed circuit card.
ally, however, itmay. benecessary to sacrifice this ad-:
vantage in favor of increasing the number of circuit lines to the .card. In this; event, ,as shown in;FIC iURE 8, ineach'vertical station of the: plug contacts, strips 92a and. 92b are separated to terminate in electrically disconnected.
tangs 94a and94b projecting from the bottom side of plug' block 96 sand contact blades 98tz'and 98b on the -..front .face of the block, respectively. Tang ,94a} may: then be solder-connected to a printed circuit line 100a onthe upper side of ;circuit card .102, for example, while tang 94b connects with another circuit line 1001:: on the lower side of circuit card 102.
In this specification and accompanying. drawings, I have shown and described apreferred :embodiment of my Alternativelygas shown in-FIGURE'7, the plug block invention and suggested various modifications; but it is to be understood that these are not intended to be -exhaustiye nor limiting of the invention but, on the contrary, are given for purposes of illustration in order that others skilledin the art may fully understand the invention and the principles, and the manner of applying it in practical I an array of side-by-side spaced metallic conductors supported in a block of insulating material, each conductor terminating in a contact member projecting through a flat face of the block, said contact member being generally of solid rectangular cross-section but having rounded corners on one side, the surface of said one side between the rounded corners being fiat and constitutingithe major part of the width of the contact member, and external circuit engaging means integral with said conductors and projecting from another face of said block.
2. A plug contact block for cooperation with plural socket-contact blocks comprising an array of side-by-side spaced bus bars embedded in a block of insulating material, plural strips integrally extending from opposite side edges of each bus bar and terminating in similar contact blades projecting through opposite faces of the block to a similar extent, similarly positioned blades along the plug block defining a row for cooperative engagement with the socket contacts of a socket contact block, guide pins projecting from the face of the block at each end of each row ,of blades, the*guide pins at the ends of each row having different orientation relative to the row for orienting the socket blocks.
3. A 'plug contact block for cooperation-with plural socket contact blocks comprising an array of spaced sideby-side bus bars embedded in a block of insulating. material, multiple strips integrally extending from side edges of each bus bar, one of said strips of each bus bar having lateral tang means projecting through a fiat side of the block, said tang means being short and narrow flat'members relative to said bus bar so as to be insertable in apertures of a printed circuit card for solder connection with the printed circuit linesthereof, plural strips of each bus bar terminating in similar contact blades projecting through at least one side face of the block to a similar extent, similarly positioned blades along the plug block defining a row for cooperative engagement with the socket contacts of a socket contact block.
References Cited by the Examiner UNITED vSTATES PATENTS 1,595,107 8/1926 Lyng et al. 339-198 2,483,551, 10/1949 Libman 339-18 2,740,944 4/1956 Harrison et al. 339-196 2,791,755 5/1957 Hammell 339-258 2,917,724 12/1959 Jackson 339-198 2,924,808 2/1960 Hewes et a1 339-210 X 2,965,872 12/1960 Linn 339-198 X 2,994,056 7/1961 Fox 339- 220 X 3,018,568 1/1962 Tischler 339-17 X 3,129,991 4/ 1964 Schmitz 339-17 FOREIGN PATENTS 69,606 7/ 1958 France.
1,205,909 8/ 1959 France.
EDWARD C. ALLEN, Primary Examiner.
RICHARD E.- MOORE, Examiner.