Electrical Connector

Abstract

A plug in electrical connector for receiving the plug end of a printed circuit board. The connector includes a housing means having a receptacle for receiving the plug end of a circuit board. The periphery of the receptacle is resilient for nonabrasively receiving the plug end of the printed circuit board and provides electrical contact with the plug end of the printed circuit board. A tension means is mounted in the housing means out of contact with the resilient peripheral boundaries of the receptacle urging the boundaries toward the plug end of the circuit board with a force sufficient to establish electrical contact between conductor paths extending along the receptacle and the conductor paths extending along the plug end of the circuit board. The connector is miniaturized and adapted to interconnect a plurality of circuits in an information storer to a plurality of circuits in a drive device without damage to such circuits.

Description

This invention relates generally to plug in electrical connectors for printed circuit boards and more specifically to electrical conductive receptacles nonabrasively receiving electrical conductive paths extending along the plug ends of printed circuit boards.

A variety plug in electrical connectors receiving the plug ends of printed circuit boards are known. One such known connector includes a plurality of contact springs arranged adjacent to one another, in a strip form for contacting various electrical circuits. In this type of connector, the contact springs are designed in such a manner that they generate the necessary contact pressure on one side thereof and lead wires and the like are soldered onto the other side to provide an electrical path away from the contact springs. The disadvantage of this type of electrical connector is that the number and width of the electrical paths are limited. The contact springs have to be thick enough and strong enough to provide the necessary soldering areas and contact pressure and they must be separated by insulating parts to avoid shorts and the like. A further drawback of these known electrical connectors is that they abrasively receive the plug end of the printed circuit board and, of course, thereby wear out the electrical paths on the plug end of the printed circuit board or on the contact springs.

Another known electrical connector includes a contact spring strip consisting of two rails or bars swingably connected with one another and forming a fork. An insulating plate material is clamped between the two rails in such a way that circuit lines are pressed against the contact elements held on the bar. The contact elements of this type of electrical connector are formed in such a way that they are deformed under the action of the contact of pressure so that the points of contact are shifted on the electrical circuit. In this matter the electrical circuits become worn, naturally this is undesirable.

Another known electrical connector is arranged to provide the necessary contact pressure after the plug end of the printed circuit board has been inserted. One particular form of this type of electrical connector suggests that the two connecting portions to be joined and contact each other at a particular angle. The contact pressure is then again generated by providing a straight-line pressure on the angularly joined plug parts. Another form of this type of electrical connector utilizes a rotary wedge or key to generate the necessary electrical contact pressure.

The common feature of these variously known electrical connectors is the double function of the resilient receptacle, which includes conducting the electrical current and generating the required contact pressure. Since this requires the mutual insulation of the spring elements, the number of circuits lying adjacent to one another per unit length is limited. However, this is undesirable in present day technology wherein miniaturization requires greater density of circuits.

Accordingly, it is an important object of the instant invention to provide a plug-in electrical connector overcoming at least some of the aforesaid disadvantages and providing nonabrasive electrical contact between multicircuit devices.

It is yet another object of the invention to provide an electrical connector which nonabrasively receives the plug end of a printed circuit board and thereafter provides the necessary electrical contact pressure.

It is yet another object of the present invention to provide an improved electrical connector of minimal size and having nondamaging electrical contacts between a plurality of electrical circuits.

In accordance with the principles of the invention, a housing means is provided having a cavity which is lined with an electrical contact means and this electrical contact lining is urged toward the center of the cavity and a tensioning means is mounted on the housing means out of contact with the lining means for further urging of the lining means toward the center of the cavity.

Other and further objects, features and advantages of the present invention will become apparent to those skilled in the art from the following description of the instant invention and the drawings attached hereto and made a part hereof.

ON THE DRAWINGS

FIG. 1 is essentially an elevated sectional view of an electrical connector constructed in accordance with the principle of the invention and receiving a pronged contact member;

FIG. 2 is essentially a partially cutaway plan view of the structure shown in FIG. 1; and

FIG. 3 is an essentially partial cutaway elevational side view with parts cut away illustrating another embodiment of an electrical connector constructed in accordance with the principles of the invention and receiving a prong contact member.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In accordance with the principles of the instant invention, the desired circuit paths (printed or otherwise provided) may be extremely and almost arbitrarily narrow since the electrical contacts are not made or brought about by a special plug device but by similarly narrow circuit paths. The contact pressure is distributed uniformly over all of the electrical contact areas so that each such area is subjected to the same contact pressure. Thus, the invention provides an electrical contact means having a plurality of circuits thereon, such as a copper-lined etched foil, which is mechanically and electrically positively joined with a plurality of cooperating circuits on a plug end of a printed circuit board, and is easily detachable without damage to such circuits. The contact pressure provided by the instant connector is preferably about 50 p. Further, there is no shifting or relative movement between the circuits on the connector and on the plug member during the attachment or detachment thereof. This is particularly important since generally the electrical contact means comprises synthetic resinous plastic foils of about 5 .mu. m. thick and having cemented or etched copper layers of about 17 .mu. m. thick thereon to define the desired circuits and any shifting or abrasive movement between such circuits would, naturally readily grind down or wear out the conductor layers and thereby destroy the circuits.

Preferably the electrical connectors of the instant invention are constructed in such a manner that the plug end receiving receptacle has a resilient boundary providing an electrical contact with the contact surfaces extending along the plug end of the printed circuit board and a tension means is mounted out of contact with such a resilient electrically conductive peripheral boundary and urges the boundary toward the plug end of the printed circuit board with a force sufficient to establish electrical contact between the boundary and the contacts on the plug end of the printed circuit board. Further, in this manner the resilient boundary is able to compensate for any inequalities in the thickness of the conductor material defining the circuits on the plug surface.

The electrical connector of the instant invention is particularly useful to provide electrical connection between the word and bit lines emerging from a thin-layer storer and appropriate operating lines of a drive device. The electrical connector of the invention may be composed entirely of nonmagnetic material thereby avoiding a magnetic influence on an information storer or the like. Preferably, such nonmagnetic materials are selected from the group consisting of nonferrous metals and resinous synthetic materials, i.e., plastics. Further, the electrical connector of the instant invention is constructed as to provide the desired nondestructive or nonabrasive electrical contact between a plurality of circuits while maintaining its total height below 10 mm. This size dimension is of considerable importance in miniaturization and should not be underestimated since the prior art devices fail to achieve such dimensions.

Referring now to the drawings, wherein like reference numerals refer to like parts, and first particularly referring to FIGS. 1 and 2, it will be seen that a housing means 1 is formed from two matching shell halves 1c. As will be appreciated, the housing means 1 may be constructed of a single-piece or two half-shells as described. The housing means 1 has a cavity 1a formed therein and a conductive receptacle 1b extends within the cavity 1a to receive the plug end 9 of a printed circuit board. When the housing means is constructed of two shell halves as shown, a clamp device 2 is provided to hold one of the edges of the shell halves together while leaving the opposed edges free for insertion of the plug end 9 of the printed circuit board. The clamp device 2 may comprise a C-shaped spring member fitting into outwardly opening recesses in the outer periphery of the shell halves. A plurality of such spring members arranged in end-to-end relation may be provided where required. Of course, if desired, a unitary construction of housing means may be utilized and the clamp device dispensed with.

An electrical contact means 4 in the form of a flexible conductor strip or band provides an electrical contacting path between the conducting surfaces extending along the plug end 9 of a printed circuit board. Said contact means may be connected to an information storer, (not shown) to interconnect a plurality of circuits to an appropriate drive device outside the electrical connector. The electrical contact means 4 (or conductor strip) comprises a plastic foil or band carrying a plurality of conductor circuits 11 along a surface thereof. The conductor strip 4 extends along the interior of a contact pressure spring 3. The contact pressure spring 3 is generally in the form of a U-shaped spring and has a pair of wavelike or undulating legs having outwardly turned outer end portions engaging facing notches in the interior walls of the shell halves 1c of the housing 1. The flexible strip 4 is adhesively or otherwise secured to peaked portions of the waves of the U-shaped spring 3. A contact pressure means 5 is provided at the base of the U-shaped spring 3 between the legs thereof, to separate the bight portion of the flexible conductor strip means 4 inside the cavity 1a. Preferably, the strip means 4, the U-shaped spring 3, and the contact pressure means 5 are all cemented together to form a single structure and for ease of manufacture may be preformed and inserted into the cavity as a single unit. The tension device 3 is preferably in the form of a plurality of spring leaves appropriately formed and having a width dimension sufficient to cover at least two adjoining circuit paths 11. In this manner, any uneveness in the surface of the plug end 9 of the circuit board or in the conductor circuit 11 on the flexible strip means 4 on both sides of the connector are compensated for.

The electrical contact means or conductor strips 4 extend about the ends of the shell halves 1c and rearwardly along the outer sides thereof and may be attached to the outer peripheral surfaces of the housing means 1 by an appropriate means, such as screws. In order to protect the strips 4 and provide a desired degree of stiffness for fastening purposes, two Hp plates 7 and 8, composed of, for example, hard paper plates or the like are cemented about the portions of the strip 4 extending the shell halves of the housing means 1.

The dimensions of the housing means cavity 1a and its resilient electrically conductive peripheral boundaries, as defined by tension means 3 and lining strips 4 allow the plug end 9 of the circuit board to be nonabrasively received into the housing means cavity during the insertion thereof into the receptacle 1b. The circuit paths on the strip 4 and on the plug end 9 are thus brought into current conductive engagement with one another without the exertion of any contact pressure between such circuits paths.

The required electrical contact pressure is provided by moving a second spring member 6, which in the embodiment shown, is in the form of a U-shaped spring, along the outer sides of the housing means 1 along guide grooves 6a into engagement with outwardly opening notches at the outer ends of said guide grooves and urging the flexible contact strips 4 toward the center of the receptacle. Of course, in removing the plug end 9 of the circuit board, the tensioning device 6 is first removed to discontinue the contact pressure (i.e. about 50 P) and then the plug in 9 of the circuit board is removed from the receptacle of the electrical connector. Thereby any damage, such as by rubbing or abrasion, of the thin and very delicate conductor paths on the electrical contact means 4 or on the plug end of the circuit board is prevented and the connecting operation can be repeated as often as desired without damage to the conductor of the printed circuit.

It will be noted that the tension device 6, which in the embodiment shown is generally a U-shaped spring member having a center wall and upstanding sidewalls, has portions thereof, i.e., the sidewalls, of substantially the same length as the cavity peripheral edges and thereby is able to provide uniform pressure along the entire cavity periphery. In this manner the pressure exerted by the U-shaped spring 3 by the compressive effect of the U-shaped spring 6 is uniformly distributed onto the circuit paths. It will be appreciated that through appropriate dimensioning of the two U-shaped springs 3 and 6, any damaging deformation of the U-shaped spring 3 or inequities in the pressure relationships is avoided.

This type of construction for electrical connectors allows a relatively great variation in the thickness of the contacts of the plug end of the circuit board with only a slight variation in the contact pressure generated between the plug member and electrical contact means of the connector.

As shown in FIG. 2, appropriate guide strips 10 extend along opposite sides of the ends of the plug end 9 of the circuit board to guide and confine of the connector in a manner well understood in the art. Conveniently, the guide strips 10 are attached to the housing 1 of the electrical connector by any conventional means, as by a conventional screw fastener, secured to the projecting ends of the clamp 2.

Referring now to FIG. 3, wherein a plurality cutaway side view of another embodiment of plug in electrical connector constructed in accordance with the principles of the invention is shown which utilizes a rotary key or wedge to provide the electrical contact pressure. It will be seen from FIG. 3 that a housing means 1 (which may be composed of two shell halves) is provided with a pair of lateral side plates 14. The sideplates 14 function as a bearing means for an eccentric device 13 and for a contact pressure device 5. The sideplates 14 also function as guiding boundaries for the insertion of a plug end 9 of a circuit board. The eccentric 13 is movable in the directions indicated by the double headed arrow so as to present one surface thereof against a contact pressure key 15 and shift the key 15 in the direction of the spring or tension device 3. Of course, the eccentric 13 also has another surface portion whereby this pressure is released. In this manner the arching or deformation of the tensioning device 3 is increased and the necessary contact pressure is generated.

An elastic support 16 is provided between the contact pressure device 5 and the electrical contact means or strips 4 lining the cavity 1a in the vicinity of the contact pressure key 15. The elastic member 16 compensates for any slight change in length that the strips 4 undergo during the generation of contact pressure by the movement of the eccentric 13. It will also be noted that this embodiment illustrates a somewhat different means for fastening the strips 4 to the housing means 1, however, this does not affect the function of the connector of the instant invention and need not be described in detail.

In summation, it will be seen that the instant invention provides improved form of plug in electrical connector for receiving the plug end of a circuit board, comprising a housing means having a cavity formed therein and a receptacle for the plug end of a circuit board extending along the cavity and defining an insertion axis along with the plug end of the circuit board is received, the receptacle has resilient electrically conductive peripheral boundaries providing electrical contact with the conductor path extending along the plug end of the circuit board and the electrical connector; a contact pressure means in the form of a U-shaped spring is mounted on the housing means out of contact with the resilient conductive receptacle urging the shell halves toward the axis of the receptacle under a force sufficient to establish electrical contact. An eccentric device is mounted on the housing means and movable into a position to generate the necessary contact pressure between the conductive boundaries of the receptacle and plug end of the circuit board, after insertion of the plug end of the circuit board into the receptacle. The electrical connector thus allows a plurality of delicate circuit conductors to be electrically engaged without damage to such conductors. Further, the overall structure of the connector is readily miniaturized and composed of nonmagnetic materials making it exceptionally suitable for interconnecting complex magnetically affected electrical circuits.

Claims

We claim:

1. In a plug-in electrical connector for nonabrasively receiving and connecting the plug end of a printed circuit board to at least one flexible multiple conductor strip,

a housing having two shell halves having abutting engagement with each other at one end thereof and having spaced facing walls forming a cavity, the center of which defines an insertion axis along which the plug end of the printed circuit board is inserted,

a U-shaped contact pressure means mounted in said cavity and having a base at the inner end of said cavity and parallel legs extending from said base along said facing walls and having abutting engagement with said walls at the outer ends thereof,

at least one flexible multiple conductor strip extending along said parallel legs in the general form of a U and leaving a plurality of conductor paths facing each other and defining a plug receiving receptacle, nd

other pressure means exerting pressure on said U-shaped contact pressure means and biasing said conductor strips into conducting engagement with conductor strips extending along the plug end of the printed circuit board.

2. The plug-in electrical connector of claim 1,

wherein the shell halves are movable towards and from each other,

and wherein the other pressure means comprises a U-shaped spring extending along opposite sides of said shell halves and biasing said first U-shaped pressure means and conductor strips into current conducting engagement with the plug end of the circuit board.

3. The plug-in electrical connector of claim 2,

wherein the first U-shaped contact pressure means has wavelike legs extending from the base thereof having facing peaked portions engaging the flexible multiconductor strip, and valley portions engaging said wall portions of said shell halves, and

wherein the outer end portions of said legs have interengagement with said wall portions, to force said peaked portions toward the plug end of the circuit board by the compressive force exerted by said second mentioned U-shaped spring.

4. The plug-in electrical connector of claim 2, including a C-shaped clamp holding the inner ends of aid shell sections together and in the region of abutting engagement of said shell section with each other and accommodating movement of said shell sections relative to each other about the region of abutting engagement of said shell sections.

5. The plug-in electrical connector of claim 2, including a resilient pressure strip extending along the inside of said multiconductor strip into engagement with a base thereof and along the conductive surfaces thereof for a short portion of the length thereof.

6. The plug-in electrical connector of claim 4,

wherein the conductor strip extends along the outer ends of said shell sections and rearwardly along the outer walls thereof, and

wherein insulating strips extend along opposite sides of said multiconductor strip extending along the outer sides of said shell sections and are secured to said shell sections.

7. In a plug-in-type electrical connector for receiving the plug end of a printed circuit board having a plurality of conductor strips extending therealong and for connecting the conductors strips with at least one flexible multiconductor tape,

a housing having a closed end and an open outer end and having facing interior walls defining the inner margins of said open outer end and forming a cavity to receive the printed circuit board,

a first U-shaped contact pressure means extending within said cavity along said interior walls and having a base disposed adjacent the inner end of said cavity, and parallel legs extending along said interior walls,

abutment means abuttingly engaged by the outer ends of said legs adjacent the open end of said cavity,

at least one flexible multiconductor strip extending along the legs of said pressure means having conductor paths facing each other and defining a plug receiving receptacle,

a turnable eccentric member rotatably mounted in said housing adjacent the inner end of said cavity and effective to exert pressure on said base of said U-shaped pressure means and flex said legs toward each other to provide the required contact pressure between said conductor strip and the conductor paths extending along said plug end of the printed circuit board.

8. The plug in electrical connector of claim 7,

wherein the legs of said U-shaped contact pressure means are wavelike having peaks and valleys in which the peaks of the legs engage said flexible multiconductor strip and the valleys engage said inner walls of said housing,

whereby pressure on said base effected by operation of said eccentric member flexes the peaked portions of said waves toward each other to provide the required pressure to effect contact between said multiconductor strips and contact paths extending along the plug end of the circuit board.

9. The plug-in electrical connector of claim 8, including a block slidably mounted in said cavity between said sidewalls and interposed between said eccentric and the base of said U-shaped contact pressure means.

10. The plug-in electrical connector of claim 8, wherein the housing is composed of a nonmagnetic material selected from the group consisting essentially of nonferrous metals and synthetic resinous materials.