US3484935A - Method of producing electrical circuit assemblies having through connectors - Google Patents

Description

Dec. 23, 1969 J. A. BURNS METHOD OF PRODUCING ELECTRICAL CIRCUIT ASSEMBLIES HAVING THROUGH CONNECTORS Filed July 28, 1965 4 Sheets-Sheet 1 f 1| I 73 72 j/ W I 6/ 3,484,935 METHOD OF PRODUCING ELECTRICAL CIRCUIT ASSEMBLIE Dec. 23, 1969 J. A. BURNS HAVING THROUGH CONNECTORS 4 Sheets-Sheet 2 Filed July 28. 1965 INVENTOR dflH/V 4.

J. A. BURNS 3,484,935 METHOD OF PRODUCING ELECTRICAL CIRCUIT ASSEMBLIES Dec. 23, 1969 4 Sheets-Sheet 3 Filed July 28, 1965 INVENTOR. JJH/V 4. awe/v5 Dec. 23, 1969 J. A. BURNS 3 484,

METHOD OF PRODUCING ELECTRICAL CIRCUIT ASSEMBLIES HAVING THROUGH CONNECTORS 4 Sheets-Sheet 4 Filed July 28, 1965 INVENTOR. JflH/V ,4. 503/10- Patented Dec. 23, 1969 3,484,935 METHOD OF PRODUCING ELECTRICAL CIRCUIT ASSEMBLIES HAVING THROUGH CONNECTORS John A. Burns, New Hope, Pa., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed July 28, 1965, Ser. No. 475,461 Int. Cl. H05k 3/30; H01r 9/00 US. Cl. 29-628 4 Claims ABSTRACT OF THE DISCLOSURE An electrical circuit assembly is produced from the following starting products:

(a) a board having at least one aperture therethrough and circuit elements on the board adjacent the termini of the aperture; and

(b) a connector segment comprising an axially and radially plastic, elongate core which supports longitudinally at least one conductor. The core possesses a natural transverse dimension and length greater than the trans verse dimension and length, respectively, of the aperture.

The segment is inserted longitudinally into the wider opening of a funnel-like member. The smaller opening of the member is axially aligned with and positioned contiguously with the aperture. The connector segment is urged through the funnel. Such urging effects serial transverse compression of portions of the segment by the smaller opening. The compressed segment is inserted into the aperture until the ends of the segment protrude from both termini of the aperture. Such protrusion permits the core to assume a transverse dimension greater than the transverse dimension of the aperture to flare the conductor outwardly for contacting respectively and interconnecting the circuit elements.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a method of producing electrical circuit assemblies and particularly to a method of associating through connectors with circuit boards to selectively establish electrical interconnections between circuit elements mounted on opposite sides of the boards.

Description of the prior art In United States patent application Ser. No. 322,607, filed Nov. 12, 1963, now Patent No. 3,268,652, there is shown and described a novel compliant and redundant through connector. The term redundan characterizes the connector as one which possesses a plurality of possible interconnection paths between circuit elements, such as conductive paths, on opposite sides of a circuit board. Any one of the paths is sufficient to effect the desired interconnection.

The connector comprises a resilient core which is laterally and longitudinally extensible and compressible. The core is a support on which a bent connector is wound. The term bent connector denotes an electrical conductor which extends in a direction other than parallel to the axis of the resilient core and which, in various forms as the occasion may require, may comprise a sleeve-like wire braid or mesh or one or more conductors wound helically about the resilient core.

The resilient core of the compliant and redundant through connector, provides a means for readily sealing an aperture in a circuit board through which the connector is inserted. Moreover, the through connector may expand and contract readily as the circuit board expands and contracts, thereby avoiding strain on any interconnections made to circuit element on the board. Additionally, the connector is especially useful where electrical interconnections are to be established between circuit elements adjacent to each end of the aperture in the circuit board.

SUMMARY OF THE INVENTION Accordingly, an object of this invention is to provide a new and improved method of producing electrical circuit assemblies.

Another object of this invention resides in the provision of a new and improved method of associating through connectors with circuit boards to selectively establish electrical interconnections between circuit elements mounted on opposite sides of the boards.

With these and other objects in view, the present invention contemplates a new and improved method of producing electrical circuit assemblies. First, a connector segment is produced which includes a resilient core about which is wound helically one or more conductors.

The connector segment is next confined within and radially compressed by an open-ended funnel-like member the smaller end of which has a diameter equal to or less than the diameter of an aperture in a circuit board. The smaller funnel end is axially aligned with and placed adjacent to the aperture and the connector is then easily inserted thereinto until the ends of the connector segment extend approximately equally out of each end of the aperture. Since such connector segment ends are subject to neither the radial compression of the funnel nor the confining force of the aperture, the resilient core expands and flares portions of the connector segment and the surface of the terminal board, and is mechanically fixed in position. Subsequent soldering operations thereafter establish permanent electrical contact. Because the resilient core has closed and sealed the interior of the aperture, such soldering does not result in the flow of any solder into the aperture to stiffen the connector segment or otherwise interfere with the resilience of the through connector.

BRIEF DESCRIPTION OF THE DRAWINGS Other objects and advantages of the present invention will become apparent upon consideration of the following detailed description in conjunction with the following drawings, wherein:

FIGURE 1 depicts a circuit assembly and is a crosssectional view through a circuit board having an aperture through which there has been inserted a through connector of the type described in US. Patent No. 3,268,652 by the method of the present invention;

FIGURES 2, 2a, 3 and 4 are cross-sectional views showing successive steps of the present method for insertion of the through connector into the aperture of the circuit board to produce the circuit assembly of FIG- URE 1;

FIGURES 5, 6, 6a, 7 and 8 are schematic views showshowing apparatus utilized to practice the method shown in FIGURES 2, 2a, 3 and 4.

Referring first to FIGURE 1, there is shown a novel electrical circuit assembly 25 which comprises a board 26 having an aperture 27 therethrough and intersecting the surfaces 28 and 29 thereof. A flexible, resilient H through connector 30 which may be generally cylindrical in cross-section comprises a central resilient core 31 having a natural length 32 and transverse dimension which exceed the length 33 and transverse dimension of the aperture 27. One or more conductors 40 are attached to the core 31, such as by braiding or spiral forming, for electrically interconnecting electrical elements 41 and 42 (which may be metallic eyelets) on opposite sides of the board 26 adjacent the aperture27. Ends 43 and 44 of the conductor 40 on protruding ends 45 and 46 of the resilient core 31, are flattened against the elements 41 and 42, respectively, and may be soldered thereto. The connector 30 may include a plurality of conductors 40, only one of which may be necessary to effect electrical interconnection of the elements 41 and 42. Therefore, such connector may be designated a redundant connector.

The possibility exists that the circuit elements 41 and 42 and the conductor ends 43 and 44 may move relatively due to dimensional changes of the board 26 in response to changes in ambient conditions. Such relative movement exerts forces on the connector 30. However, the connector 30 is compliant (or resilient) and flexible. The terms complaint, resilient and flexible, as used herein, indicate that the connector 30 is capable of being flexed or bent in response to a tensile or compressive force exerted thereon without damage either to such. connector 30 or to solder joining the conductor ends 43 and 44 to the elements 41 and 42.

As shown in FIGURE 1, the conductor ends 43 and 44 are flared outwardly and pressed flat so that they extend away from the aperture 27 parallel to the circuit board surfaces 28 and 29. Such ends 43 and 44 are pressed down flat against the elements 41, 42 and are, thus, capable of having a large area of contact therewith, thereby providing not only a good electrical connection but also a good surface-to-surface contact. Solder may be applied to of such end 46 and also of the conductor end 44. While the ram 73 is in the position shown in FIGURE 2a the locating and flaring ram 70 is again raised to engage the center of the protruding core end 46 to press such end outwardly sufliciently so that the conductor end 44 assumes a position parallel to the surface board 29 in intimate ,surface-to-surface relation with the element 42 thereon (see FIGURE 3).

The element 42 may be an eyelet, a printed pattern, or other electrical element which is adjacent the aperture 27. With the locating and flaring ram 70 now in the position of FIGURE 3, the member 60' is now raised thereby pulling the funnel-shaped opening 62 over and away from the core end 45. As the end 45 emerges from the funnelshaped opening 62, it is no longer compressed thereby and assumes a size larger than both such opening 62 and the aperture 27 e The member 60 is now brought down again to the position shown in FIGURE 4 .whereat a lower surface 76 thereof engages the core end 45 to flatten such end. Such flattening presses the conductor end 43 outwardly to assume aposition parallel to the board surface 28 in intimate contact with the element 41 (which may be similar to the element 42). If the elements 41, 42 are not used, the outward flaring of the conductor ends 43 and 44 produces a more than adequate means to which electrical connection can easily be made.

An important step of the method is the compression of the connector segment 72 so that such segment may be forced into the smaller aperture 27. The conductor segment 72 is sufliciently long to protrude from both ends of the aperture 27 The segment 72, having been axially compressed by the tapered funnel-shaped opening 62 and such area of contact to further assure a good mechanical as Well as a good electrical connection.

FIGURES 2, 2a, 3 and 4 illustrate the method of associating the compliant through connector 30 with the board 26 according to the present invention. The aperture 27 is positioned beneath a member 60 having a cylindrical opening 61 therethrough which is greater in diameter than the diameter of the aperture 27 The lower end of the opening .61 is funnel-shaped or conically tapered, as shown at 62. The tapered funnel-shaped opening 62 has the same or a smaller diameter than the aperture 27. p

conductor 40) is positioned in the opening 61, a ram 73 I is lowered into the opening 61 radially compressing the segment at the funnel-shaped opening 62 and forcing the compressed segment 72 out of the opening 62 and into the aperture 27. The member has previously been brought into contact with the board 26 so that the openings 61 and 62 are contiguous with the aperture 27. The segment 72 remains radially compressed withinthe aperture 27. At the same time the locating ram carrying three locating pins 70a is removed from the aperture 27.

The ram 73 descends into the opening 61 to a position, as

shown in FIGURE 2a, just above the funnel-shaped opening so that the end 46 of the core 31 protrudes from the aperture 27 As the end 46 of the core 31 emerges from-theaperture 27, it is no longer compressed by such aperture 27 and assumes its original condition which is larger than the diameter of the aperture 27 to produce a conical flare then forced into the aperture 27, is pushed through the aperture 27 until the core ends 45 and 46 extend through the opposite ends of the aperture. The release of the radial forces on the segment 72 permits the resilient core 31 to expand to itsinitial size, thereby causing the conductor ends 43 and 44 to flare out. Following this expansion, and while the segment is held at one end, axial force is applied to the other end to cause the core 31 to flare out temporarily further and thereby cause one or more of the conductor ends 43 to move to positions substantially at right angles to the axes of the core 31 to assume a position substantially parallel to the surface of the board 26. Thereafter, the other end 44 of the conductorprojecting through the opposite side of the board is similarly treated to cause such end 44 to b flared into a position at right angles to the axis of the core 31 and thereby to cause such end to assume a position substantially parallel to the board 26. Moreover, the aperture 27 is fully sealed by the force of the resilient core 31 of the connector segment 72 against the sides of the aperture 27.

FIGURES 5, 6, 6a, 7 and 8, show one exemplary apparatusby which the process depicted inFIGURES' 2, 2a, 3 and 4 maybe effected. In FIGURE 5 the circuit board 26 having therethrough a plurality of aperatures 27 adjoinedby circuit elements 41, 42 is shown with one of the apertures 27 located over the upper end of the locating and flaring ram 70.- The ram 70 is shown as having a locating pin conical tip 70a capable of centering the aperture 27. The aperture 27 is so dimensioned that it will rest on the sloping surface of the pin 70a thereby insuring that the aperture 27 is axially aligned with the openings 61 and 62 in the member 60. The-ram 70 extends upwardly above a support or platform on which a portion of the circuit board 26 and the contact element 42 rest'lduring the operation of the apparatus. The platform 80 is arranged so that it is parallel with the lower surface 81 of a main support 82 for a slide assembly 83. The lower surface -76 of the member 60 is also parallel to the surface 80 and to the lower surface 81 of the support 82.

A spring 85 is provided within a housing 86, the upper surface of which forms the platform 80. The spring 85 bears between asurface' 87 and a collar 88 mounted to the lower end of the ram 70 to bias such ram 70 to a retracted position. A lower extension 90* of the ram 70 rests on a movable wedge cam 91. Movement of the cam 91 in the direction indicated by the arrow 92, moves the ram 70 upwardly against the spring 85. Movement of the cam 91 in the direction opposite to that indicated by arrow 92 permits the spring 85 to drive the ram 70 down.

The entire main support 82, including the slide assembly 83 and an actuator 94, therefore, is movable downwardly toward the circuit board 26.

A cylindrical sleeve 100 surrounds the member 60 and is so arranged to allow the surface 76 to engage the upper surface of the circuit board 26. The cylindrical sleeve 100 is biased downwardly by a compression spring 101 which bears against the lower surface 81 of the main support 82 and an annular flange 102 of the sleeve 100. The sleeve 100 is guided vertically and inhibited from turning by stop members 103. Such stop members 103 are set screws which are threaded into the member 60. The set screws 103 register with a slot 104 in the sleeve 100. In the position of FIGURE 5 the sleeve 100 is biased downward so that the flange 102 contacts the set screws 103 on each side, a lower annular surface 105 of the sleeve 100 extending below the lower surface 76 of the member 60. As the main support 82 moves down from the position of FIGURE 5 to the position of FIGURE 6, the annular sleeve surface 105 engages the circuit board 26, thereby creating a uniform annular pressure around the aperture 27. .At this time the cam 91 is withdrawn to the right permitting the spring 85 to drive the ram 70 down. This permits the circuit board 26 to seat directly on the platform 80 and to be held accurately in position thereon by the annular lower surface 105 of the sleeve 100. Also, the withdrawal of the ram 70 permits the aperture 27 to be prepared for reception of the connector segment 30. On continued downward movement of the main support 82, the lower surface 76 of the member 60 engages the element 41 moving the sleeve 100 up against the spring 101. An opening 110 in the slide 83, containing the connector segment 30 which is to be fed into the aperture 27 of the circuit board 26, is now aligned with the openings 61 and 62. When the lower surface 76 of the member 60 bottoms on the connector element 41, a ram 111 is moved downwardly through a guide 112 into the opening 110 thereby pressing and pushing the connector segment 30 down from the opening 110 through the passage 61, through thefunnel-shaped opening 62 and into the aperture 27. The ram 111 is arranged to stop at the beginning of the conical opening 62. The above-described elements are so dimensioned that when the ram 111 reaches its bottommost position, the connector segment 30 has been pushed through the aperture 27 so that a desired length thereof extends out of both termini of the aperture 27. While the ram 111 is still in the position of FIGURE 6, the locating and flaring ram 70 is moved upwardly to the position shown in FIGURE 6a, by the movement of the cam 91 in the direction of arrow 92. Thef'upward movement of the ram 70 now performs the function described previously in connection with FIGURE 3. While the locating and flaring ram is in the position of FIGURE 6 the main support 82 is raised, thereby raising all of the elements connected thereto and raising the member 60. The lower surface 105 of the sleeve 100, under the biasing influence of the spring 101, returns to and remains in engagement with board 26 and holds the board in place on the platform 80 while the member 60 is lifted.

When the main support 82 and the member 60 including the funnel-shaped opening 62 are raised, the funnelshaped opening 62 is pulled off the upper end of the connector segment 72. The locating and flaring ram 70' serves to hold the segment 72 in position so that it will not be pulled out of the aperture 27 by the vertical lifting force which is imposed thereon by reason of the funnel-shaped opening 62 being sliped off. This is shown in FIGURE 7.

Following the removal of the funnel-shaped opening 62, the main support 82 is lowered once more to the position shown in FIGURE 8. Since the opening 62 is much smaller than the upper end of the connector (owing to expansion of the resilient core 31 of the connector segment 72), the lower surface 76 of the member 60 compresses vertically the end 45 of the connector 30. Such compression causes the core 31 of the connector 30 to be radially expanded as shown in FIGURE 8. When the main support'82 is lifted once more, the ram 70 drops and the circuit board 26 may be removed. It should be noted that it is not necessary to drop the ram 70 in order to remove the circuit board 26. Thus, pin 700 may be left up as a locator for the next aperture 27.

Thus far the structure of FIGURES 5, 6, 6a, 7 and 8 has been described with a view towards describing solely the function of inserting the connector 30 into the circuit board. There is an additional function which will be obvious from examination of FIGURE 5 which relates to the manner of feed to the connector material from a supply to the slide 83 and the movement of the slide 83 to a position where the opening in the slide 83 registers with the guide 112 and the opening 61.

There may be provided a reel of braided wire .121 arranged over a continuous resilient core material 122, forming a connector segment supply 123. The supply 123 is fed from the reel 120 into a stationary guide 124 in the main support 82. The slide 83 previously mentioned is operated by a connecting rod from the operator 94. In the initial feed position from the reel 120, the opening 110 in the slide member '83 is positioned directly under and axially aligned with the guide 124. At this time a selected length of the supply .123 is fed through the guide 124 into the opening 110. The feed will be stopped when the selected length of supply 123 has entered such opening 110.

On completion of the feeding operation, a standard scissors mechanism (not shown) arranged along the horizontal line 131 is operated to sever the length of supply 123 leaving an appropriate length of such supply in the opening 110 of the slide 83 to form the connector segment 72.

On completion of this severing operation, the slide operator 94 is operated to move the slide 83 toward the left to a position as shown by the opening 110 in phantom in FIGURE 5. The slide 83 is halted when the opening 110 is axially aligned with the guide 112 for ram 111 and the opening 61 of the member 60. On completion of the full flaring operation, the slide 83 is returned from the phantom left-hand position of FIGURE 5 to the solid line right-hand position of FIGURE 5 where the opening 110 is ready once more to receive a length of supply 123 from the reel 120.

On return of the slide 83 to the right of FIGURE 5 a supply feeder 136 is energized. The feeder 136 comprises an operating member which has vertical movement from the solid line position to the lower dotted line position and horizontal movement from the solid line to the dotted line positions shown. When the operating member 135 is driven to the left from the solid line position toward the dotted line position, a plurality of pins 140 enter between the interstices of the braided wire 121 and engage a portion of the resilient core material 122. Thereafter, the operating member 135 is moved from the upper position to the lower position shown, thereby pulling a length of the supply 123 off the reel 120 and driving the free end of the supply 123 down through the guide 124 past the severing position 131 and into the vertical opening 110 of the slide 83. Thereafter, the scissors (not shown) are operated to sever the length of supply 123 in the guide 110 to form the connector segment 72; the member 135 is then drawn toward the right todisengage the pins 140 from the supply 123 and then raised up! wardly to its initial solid line position where it is ready to repeat the operation.

All of the operations described above may be effected by standard mechanisms, such as air piston-cylinders, rack-pinion sets, etc. Further, such mechanisms may be operated in the appropriate timed sequence by the inclusion thereinto of timing circuits and electricalair valves.

Such mechanisms, circuits and valves are believed to be within the skill of the art and are not here described. Of

special interest are the operations of'the cam 91 and the ram 70; the main support 82; the ram 111; the slide 83;

and the feeder 136. I I

Many variations and modifications of the present invention will now be apparent to those skilled in the art.

Therefore, this invention is to be limited, not to the specific disclosure herein, but only by the appending claims.

What is claimed is: p

1. The method of inserting a resilient, elastic through connector which includes thereon a flexible conductor into an aperture of a circuit board comprising:

' confining said connector within a funnel-shaped restricting means having an openin of diameter no greater than the diameter of said aperture;

inserting said confined connector into said aperture until upper and lower connector portions extend out from opposite sides of said aperture, said lower connector portion expanding upon passing out of said aperture, said upper portion remaining confined within said restricting means;

flaring said expanded lower portion by applying first axial compressive forces to said lower connector portion until an end of said conductor thereon is positioned generally parallel to the surface of said board;

maintaining the application of said first axial forces while removing said upper connector portion from said restricting means to allow said upper connector portion to expand; and then flaring said expanded upper connector portion by applying second axial compressive forces to said upper connector portion until an end of said conductor thereon is positioned generally parallel to the surface of said board.

2. A method of producing an electrical circuit assembly which includes:

(A) a generally planar board having at least one aper ture therethrough and at least one electrical element on each side of the board adjacent the respective opposed termini of the aperture; and

(B) a connector segment comprising at least one continuous, flexible conductor on a compressible elastic,

, elongate core, said segment having a natural transment until said compressed segment has a transverse dimension smaller than said transverse dimension of said aperture; I I

(1) applying transverse compressive forcelto said seg- 8 (2) inserting axially said compressed segment into said aperture by applying 'longi'tudinalforceto a first segment'end until both said first segment end and second s'egment'end extend beyond said opposed termini of said aperture; (3) while maintaining said longitudinal force application on said first segment end;

(a) removing said transverse compressive force from said second segment end, which end assumes said natural transverse dimension to urge the conductor end thereon toward said element adjacent thereto, and then (b) applying axial compressive force to said sec- I 0nd segmentend until said second segment end has a transverse dimension greater than said natural transverse dimension to position said conductor end thereon generally parallel to the surface of said board and to force said conductor end thereon into intimate contact with I j I said adjacent element; (4) removing said longitudinal force from said first segment end; and then (5) I while maintaining said axial compressive force ap- I 'p'lication on said second segment end, effecting steps I (3a) and (3b) on said first segment end. ,3. The method set forth in claim 2 wherein steps (1) and (2) are performed substantially simultaneously. I 4. Themethod set forth in claim Swherein step (3b) comprises a momentary force application followed by a step of: I removing said axial compressive force whereby said ex- I tending segment ends assume said natural transverse [dimension and said conductor ends remain in intii mate contact with said elements.

I References Cited T UNITED STATES PATENTS 1,474,227 11/1933 Boisset. 1 3,184,532 5/1965 Spera'.. 29626 XR 3,268,652 8/l966 Burns et'al l7468'.5

FOREIGN PATENTS ,'1,936 571926 f Australia. 1,243,746 '8/19I0 II France,

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