US3883682A

US3883682A - Circuit assembly

Info

Publication number: US3883682A
Application number: US467360A
Authority: US
Inventors: Albert W Cagle; Wayne E Greer; Wilbur J Weight
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1972-02-22
Filing date: 1974-05-06
Publication date: 1975-05-13
Anticipated expiration: 1992-05-13

Abstract

In a telephone repeater assembly, a plurality of fasteners is maintained in a self-supporting array by a framework of attached runners. The fasteners are aligned with and joined to a mating part in a pattern which substantially corresponds to the array. Flexibility of the runners permits minor adjustments to the positions of the fasteners in the array to align the fasteners precisely to the pattern on the mating part. Handling the fasteners in such an array facilitates assembly of the fasteners into the mating part. A circuit board is mounted to such part with one side thereof contiguous to the array of fasteners. The board has a plurality of apertures in addition to its mounting holes for the insertion of wide-headed contact screws. The screws are retained by the fasteners. Upon full insertion of the contact screws the head of the screws bridges a gap between two separate conductors on the board and establishes electrical continuity therebetween.

Description

United States Patent Cagle et a].

CIRCUIT ASSEMBLY Inventors: Albert W. Cagle, Raytown; Wayne E. Greer, Independence; Wilbur J. Weight, Lees Summit, all of Mo.

Western Electric Co., Inc., New York, NY.

Filed: May 6, 1974 Appl. No.: 467,360

Related US. Application Data Division of Ser. No. 228,152, Feb. 22, 1972.

Assignee:

References Cited UNITED STATES PATENTS 12/1960 DuVal, Jr. et al 317 101 CE 12/1969 Ljungdell et a1 317/101 CE [451 May 13, 1975 Primary Examiner-Darre11 L. Clay Attorney, Agent, or FirmW. O. Schellin [57] ABSTRACT In a telephone repeater assembly, a plurality of fasteners is maintained in a self-supporting array by a framework of attached runners. The fasteners are aligned with and joined to a mating part in a pattern which substantially corresponds to the array. Flexibility of the runners permits minor adjustments to the positions of the fasteners in the array to align the fasteners precisely to the pattern on the mating part. Handling the fasteners in such an array facilitates assembly of the fasteners into the mating part. A circuit board is mounted to such part with one side thereof contiguous to the array of fasteners. The board has a plurality of apertures in addition to its mounting holes for the insertion of wide-headed contact screws. The screws are retained by the fasteners. Upon full insertion of the contact screws the head of the screws bridges a gap between two separate conductors on the board and establishes electrical continuity therebetween.

5 Claims, 3 Drawing Figures CIRCUIT ASSEMBLY This is a division of Application Ser. No. 228,152 filed Feb. 22, 1972, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to expeditiously handling a plurality of fasteners and, more particularly, to a structure of fasteners for insertion into a base and to an assembly including these elements.

2. Description of the Prior Art Mechanical devices using a large number of fasteners often present a problem in their assembly in that the repetitive operation of applying the fasteners is tedious, time consuming and, consequently, expensive. Some devices, fortunately, permit automatic or semiautomatic insertion of fasteners.

Other devices do not readily lend themselves to being assembled by automatic machinery. A few of the latter devices present a compounded problem, in that both male and female fasteners are required in the assembly.

For example, a particular assembly includes a printed circuit board and a plurality of fasteners. The printed circuit board has a repetitive pattern of printed conductor terminals on opposite sides of an aperture in the board. Upon insertion of a screw into the aperture, the head of the screw bridges the gap between the conductor terminals to establish contact between the conductors. A lock nut on the reverse side of the board retains the screw in contact with the terminals. Because of the number of these circuit connections in the board, its assembly becomes quite cumbersome.

A known fastening device has limitations which make it inapplicable for use in such a printed circuit board assembly. This known device combines several pairs of yieldable tongues formed in an elongated metal strip for receiving a plurality of screws. The pairs of tongues are arranged at certain intervals in the strip to guide the inserted screws into precise position with respect to the metal strip. While this device guides the inserted screws into the already established positions in the device, there is no provision for adjustment of the relative positions of the tongues by shifting their positions. Such shifting is often necessary to accommodate a variation from the established dimensions due to manufacturing tolerances.

Such lack of provision for adjustment is particularly disadvantageous where the fasteners lie in a planar, multidirectional array rather than in merely a straightline arrangement. In such a case, two-dimensional variations are to be expected which require a certain amount of adjustment to achieve an alignment of the fasteners in the array with a mating part. Such an adjustment is not possible according to the prior art.

SUMMARY OF THE INVENTION An object of this invention is, therefore, to expeditiously handle a plurality of fasteners.

Another object of this invention is to provide a new and improved structure of fasteners for insertion into a base and an assembly including these elements.

Another object of the invention is the provision of a structure for insertion into a plurality of positions in a base that are subject to variations due to tolerances.

It is another object of the invention to provide a structure of fasteners in an array of sufficient rigidity to normally maintain the fasteners in substantially fixed relation to each other, and of a resiliency to permit the shifting of the fasteners with respect to each other to compensate for misalignment between the fasteners of the array and a mating part.

According to these and other objects and advantages discussed in or apparent from this specification, the invention is summarized as follows:

The handling of a plurality of fasteners to be assembled in a pattern is facilitated by interconnecting the fasteners into an array corresponding to the pattern and by positioning the array with respect to a mating part. Deforming the interconnections between the fasteners shifts the positions of the fasteners relative to each other, such that the fasteners coincide with predetermined positions on the mating art. 4 p An assembly, according to the invention, comprises a base having a plurality of cavities located according to a defined pattern in one surface thereof, an array of interconnected fasteners located in accordance with the defined pattern in the cavities, a circuit board located with one surface thereof contiguous to the fasteners, the other surface of the board having a plurality of pairs of conductors thereon, and a plurality of screws inserted through the board into the fasteners, the screws adapted to establish electrical continuity between the conductors of each pair of conductors.

BRIEF DESCRIPTION OF THE DRAWING A complete understanding of the invention can be obtained from the following detailed description of a specific embodiment of the invention when read in conjunction with the accompanying drawing, wherein:

FIG. 1 is a perspective view of an array of fasteners according to the invention;

FIG. 2 is a perspective view of a base into which the array of FIG. 1 may be inserted; and

FIG. 3 is a perspective view, partly in section, showing an assembly of the array of FIG. I, the base of FIG. 2, a printed circuit board, and a threaded member.

DETAILED DESCRIPTION Referring now to FIG. 1 of the drawing, a structure or fastening device, designated generally by the numeral 10, is shown. The device 10 is comprised of two groups of elements, namely, a plurality of individual retainers or fasteners 11, and interconnecting members or runners 12. The runners l2 interconnect the fasteners 11 in an array, designated generally by the numeral 13, as shown in FIG. 1. The runners 12 complete the device 10 to normally retain each of the fasteners 11 in a specified position.

The fasteners 11 are preferably formed 'of a resilient plastic material such as, for example, commercially available nylon or the like. Such a material lends itself to economical processes of molding, and exhibits, after molding, a rigidity and resiliency desirable to practice the invention.

The fasteners 11, of FIG. 1, are comprised of a block of material in the shape of arr-orthogonal prism. An aperture l5 estends through each of the fasteners 11. It is possible to form threads in the cylindrical internal surface 16 of the aperture 15 to receive a threaded male member such as, for example, a screw 18 having a head 19. However, the preferred embodiment of FIG. I does not contemplate such threads. Without the threads the fastener 11 functions as a lock nut. Thus,

the screw 18 when rotatably inserted into the unthreaded aperture plastically deforms the fastener 11 to some extent in forming threads in the surface 16. Due to the resiliency of the nylon, the material of the fastener 1 1 seizes the threads 19 of the screw 18 to frictionally resist a rotational movement of such screw. This resistance to rotation gives the fasteners 11 their locking characteristic.

The runners 12 extend between the fasteners 11 to interconnect the fasteners into the desired array 13. Such runners 12 are sufficiently rigid or stiff for two important purposes: (a) to maintain the fasteners 11 in the array 13 in the desired positions with respect to each other; and (b) to render the array 13 selfsupporting. The term self-supporting, as used herein, denotes the ability of the array 13 to maintain substantially its shape and the fasteners 11 in a given plane without flexing when supported at any single point of the array.

The runners 12 also are sufficiently flexible in response to applied forces to permit an adjustment of the relative positions of the fasteners 11. Such an adjustment includes shifting selected ones of the fasteners 11 of the array 13 slightly with respect to the other fasteners 11, such that the array 13 actually becomes distorted from its normal shape.

Thus, the runners 12 satisfy two requirements: (I) they are rigid to the extent of maintaining the fasteners in the array 13 and to the extent of being, in combination with the fasteners 11, self-supporting, and (2) they are also flexible in response to forces to permit a distortion of the normal array 13 for realigning the fasteners 11. Proper selection of the cross-sectional area of each of the runners 12 depends, of course, upon a desired balance between rigidity and elasticity or flexibility to optimize the handling and adjustment characteristics of the device 10.

In a particular example of the device 10 shown in FIG. 1 the material for the fasteners 11 and the runners 12 has been chosen to be a commercial, glass-filled nylon. The center distances between two adjacent fasteners 11 in this particular array 13 vary between fivesixteenth of an inch and one and one-quarter inch. Under these conditions a cross-sectional area 21 of the runners conveniently has a semi-circular shape, approximately one-sixteenth of an inch in diameter. As shown in FIG. 1 the runners 12 lie in a single plane and are attached to the fasteners 11 at one end plane of such fasteners, such that the flat, diametrical surface 22 of the runners 12 lies in the same plane as a square end surface 23 of each of the fasteners 11.

Extending the fasteners 11 in this manner in their total length perpendicular to and on one side of the plane of the runners l2 facilitates the adjustment of two adjacent ones of the fasteners 11 with respect to each other. The free ends 24 of the fasteners 11 are movable towards and away from each other, or they may even be moved in a direction perpendicular to a common axis between such fasteners. Such an adjustment results only in minor flexing of the corresponding runner 12.

FIG. 2 shows a frame or base 25 which contains a number of cavities 26. The cavities 26 are arranged in a desired pattern 27 on centerlines substantially coinciding with those of the array 13.

The cavities 26 have a shape similar to, but slightly larger than, that of the fasteners ill to permit the fasteners 11 to slide into such cavities 26 once such fasteners are aligned with the corresponding cavities. The difference in size between the cavities 26 and the fasteners 11 is such that a rotational movement of the fasteners 11 within such cavities is constrained. However, the larger cavities 26 permits some tilting and also some lateral movement of the fasteners within the cavities after assembly. This type of movement of the fasteners 11 within the cavities 26 is referred to as floatlng.

While the square end surface 23 is convenient from the manufacturing standpoint, end surfaces having shapes other than a square are considered to be equivalent to the square shape. It is, however, preferred for the fasteners 11 to be orthogonal prisms. When the fasteners 11 are of such prismatic shape, longitudinal corners 29 of the fasteners are adjacent to similar corners 31 of the cavities 26 after the fasteners have been inserted, one into each cavity. The resulting keying action between the fasteners 11 and the corresponding cavities 26 prevent the fasteners from rotating within the cavities when a torque is applied to such fasteners.

The array 13 of fasteners 11 substantially coincides with a pattern 27, of cavities 26 in the base 25. A plurality of channels 32 accommodates the runners 12. Typically, the channels 32 are somewhat larger in cross-section than the respective runners 12. The amount the channels 32 are larger than the runners 12 is determined by deviations from the normal specified dimensions that can be expected in the manufacture of the device 10 and the base 25. In the preferred embodiment the channels 32 are larger than the runners 12 by one-thirtysecondth of an inch over the diametrical dimension of the runners 12.

Preparatory to the insertion of the device 10 into the base 25 the device 10 is aligned thereto. Upon such alignment, each of the fasteners 11 substantially coincides with one of the cavities 26 in the base 25. Then, the device 10 is inserted as a unit into the base 25.

The normal manufacturing tolerances on both the device 10 and the base 25 sometimes necessitate some adjustment to shift some of the fasteners 11 in the array 13 before the device is inserted into the base. A usually slight distortion in some portions of the array 13 ultimately results in the precise alignment of the fasteners 11 with respect to corresponding ones of the cavities 26 in the base 25.

The position of any one of two fasteners 11 of the array 13 can be adjusted with respect to the other of the two fasteners 11 by flexing the corresponding interconnecting runner 12 to align the fasteners 11 to the location of their respective cavities 26. A particular one of the runners 12 may be flexed about an axis parallel to the plane of such runner and perpendicular to its length. The resulting flexure of the runner 12, depending on its direction, either increases or decreases the center distance between the two respective fasteners 11 at the free ends 24 of such fasteners.

In addition to increasing or decreasing such center distance, one of the fasteners 11 may be shifted laterally from a line extending between the respective fastener l1 and one other adjacent fastener 11 of the array 13. Such a lateral shift with respect to such line requires a corresponding lateral flexure or a tortional flexure of the runner l2 interconnecting the two'adjacent fasteners.

Flexing the runners 12 as described permits each fastener 11 to be precisely aligned to a corresponding cavity 26 in the base 25. When, subsequent to such an alignment, the device is inserted as a unit into the base 25 some of the runners 12 will undergo an additional strain to adjust to the aligned positions of the inserted fasteners 11.

FIG. 3 shows a section of an assembly 33 including the base 25 in combination with a circuit board 34. This assembly 33 is a particular example of an apparatus which is improved by the use of the invention.

In the prior art, a particular telephone repeater circuit (not shown) utilizes a base, similar to the base 25 'in combination with the circuit board 34. The base 25 for the repeater circuit traditionally has had a plurality of cavities 26 for accepting a standard lock nut (not shown) in each of the cavities 26. These individual lock nuts are cumbersome to assemble into the respective cavities 26. To use the invention as described, the base 26 is modified to include a plurality of channels 32 between selected ones of the cavities 26. The number and location of these channels 32 in the base 26 correspond to the number and position of the runners 12 of the device 10. The addition of the channels 32 permits a flush insertion of the device 10 into the base 25 as described above.

The circuit board 34 has, in a conventional manner, a component side 36 which holds a given number of components 37. Special recesses 41 in the base 25 accept the components 37 when the board 34 is assembled to the base 25 with the component side 36 facing the base. When the board 34 is assembled in this manner, a conductor side 42 on the board 34 lies upwardly exposed. A set of oversize holes 43 accept a corresponding number of screws 44 to fasten the board 34 to the base 25. FIG. 2 shows a number of threaded portions 45 in the base 25. These threaded portions are in substantial alignment with the holes 43 in the board 34. The oversize of the holes 43 with respect to the shank 46 permits a small amount of lateral adjustment between the base 25 and the board 34 before the screws 44 are fastened to position the board.

Paired sets of conductive strips 47 on the conductor side 42 of the board 34 are normally open electric circuit terminations. The strips 47 are positioned on the board 34, such that each pair of the strips straddles one of the centers of the cavities 26 in the base 25. A number of apertures 49 through the board 34 are centered between respective ones of the paired sets of conductive strips 47 and are also centered with respect to the axes of the cavities 26 in the base 25. Each of the apertures 49 corresponds to a different pair of conductive strips 47 and also to a particular cavity 26.

An improved repeater circuit assembly, as for instance as assembly 33 shown in FIG. 3, includes the device 10. The aperture of each of the fasteners 11 of the device 10 in such assembly 33 is aligned with a corresponding one of the apertures 49 through the circuit board 34. The alignment facilitates inserting one of the screws l8 through each of the apertures 49 into one of the underlying fasteners 11 of the device 10.

The fasteners 11 lock the inserted screws 18 in place to prevent unintentional motion of such screws with respect to the fasteners 11 regardless of the amount of engagement of the screws 18 with respect to the fasteners 11. For example, a screw 18 partially inserted into one of the fasteners 11 remains secured to such fastener 11 just as another screw 18 fully inserted into another one of the fasteners 11 remains secured to that fastener l 1.

The head 19 of such fully inserted screw 18 contacts the circuit board 34, and particularly the pair of conductive strips 47 straddling the aperture 49 associated with the screw 18. The head 19 of the screw 18 when tightened against the pair of conductive strips 47 bridges the gap 51 between such strips 47 to establish electrical connection between the strips 47.

Circuit boards 47 inherently may have some surface irregularities as for instance a raised portion 52 on one of the pair of conductive strips 47 shown in FIG. 3. Without adjustment to the position of the associated fastener 11, the head 19 of the screw 18 being inserted therein is stopped by the raised portion 52 on the one strip 47. Consequently the head 19 is prevented from establishing contact with the other strip 47, and the pair of conductive strips 47 do not become electrically connected after full insertion of the screw 18 into the associated fastener 11.

The larger cavities 26 permitting movement or floating of the fasteners 1 1 within the cavities after assembly of the fasteners 11 therein avoid such non-connecting where the head 19 of one of the screws 18 fails to establish contact between the associated pair of strips 47 after such screw 18 has been fully inserted into one of the fasteners 11. When the head 19 of a screw 18 inserted into one of the fasteners 11 contacts the raised portion 52 on the strip 47 the fastener 11 floats within its cavity 26 to permit the screw 18 to tilt from its normal axis of insertion. This floating causes the head 19 to tilt with the screw 18 to establish-contact between the raised portion 52 on the one strip 47 with the lower lying second strip 47 of the pair.

The known insulating characteristics of nylon are of significance in the use of the device 10 in the assembly 33. Each of the pairs of conductive strips 47 in conjunction with one of the screws 18 is used in the completed assembly 33 as a separate, selectively operable switch to function independently from the other conductive strips 47 in conjunction with their respective screws 18. The insulating characteristics of the nylon runners 12 maintain the electrical separation between each of the fasteners 11 and their respective screws 18.

The foregoing description of the invention in relation to the circuit board assembly is for explanatory purposes only and is not to be construed as a limitation to the scope of the invention. For example, an array of fasteners may include a plurality of male fasteners in place of the described fasteners 11. Or the fasteners of an array of fasteners may be arranged in a multi-planar configuration. Many other examples, arrangements and modifications thereof are possible without departing from the scope of the invention.

What is claimed is:

1. A circuit board assembly comprising:

a base having a flat surface, a plurality of cavities located according to a defined pattern in the flat surface, and a plurality of channels located in the plane of the flat surface, each of the channels connecting one of the cavities with at least one other adjacent one of the cavities;

an array of fasteners comprised of a plurality of apertured blocks, and a plurality of runners interconnecting the blocks into a self-supporting structure, the runners positioning the blocks substantially according to the pattern of cavities in the base, each of the blocks occupying one of the cavities in the flat surface of the base, the runners being positioned within the channels;

a circuit board located with one side thereof contiguous to the flat surface of the base and to the array of fasteners, the board having (1) a plurality of apertures arranged in a pattern which coincides with the pattern of cavities, the apertures in the board being coaxially aligned with the apertures of the fasteners located within the cavities, and (2) a circuit conductor pattern on a second side facing away from the base, the conductor pattern including a plurality of conductor pairs corresponding in number to the'apertures through the board, each conductor pair straddling one of the apertures in the board; and

a plurality of wide-headed contact screws inserted into each of the apertures in the board and extending through the board into locking engagement with the apertures of the fasteners, the head of each screw adapted to make contact with both conductors of the corresponding pair of conductors for establishing electrical continuity between such pair of conductors.

2. A circuit board assembly according to claim 1, wherein the cavities have walls spaced from the surfaces of the blocks, the walls constraining rotational movement of the blocks within the cavities while permitting tilting or lateral floating of the blocks in response to inserted contact screws tilting upon contact of the heads of such screws with respective pairs of conductors.

3. An assembly comprising: a base having a plurality of cavities located according to a defined pattern in one surface thereof; an array of fasteners, interconnected by runners into a self-supporting structure, the fasteners located in accordance with the defined pattern in the cavities;

a circuit board located with one surface thereof contiguous to the fasteners, the other surface of the board having a plurality of pairs of conductors thereon; and

a plurality of screws inserted through the board into the fasteners, the screws adapted to establish electrical continuity between the conductors of each pair of conductors.

4. An assembly in accordance with claim 3 wherein the fasteners and the runners are of glass filled nylon and the runners are integrally attached to respective ones of the fasteners.

5. An assembly in accordance with claim 3, wherein the cavities and the fasteners have a square cross section, and wherein the cavities have walls spaced from the surfaces of the fasteners, the walls constraining rotational movement of the fasteners within the cavities while permitting tilting or lateral floating of the fasteners within the cavities.

Claims

1. A circuit board assembly comprising: a base having a flat surface, a plurality of cavities located according to a defined pattern in the flat surface, and a plurality of channels located in the plane of the flat surface, each of the channels connecting one of the cavities with at least one other adjacent one of the cavities; an array of fasteners comprised of a plurality of apertured blocks, and a plurality of runners interconnecting the blocks into a self-supporting structure, the runners positioning the blocks substantially according to the pattern of cavities in the base, each of the blocks occupying one of the cavities in the flat surface of the base, the runners being positioned within the channels; a circuit board located with one side thereof contiguous to the flat surface of the base and to the array of fasteners, the board having (1) a plurality of apertures arranged in a pattern which coincides with the pattern of cavities, the apertures in the board being coaxially aligned with the apertures of the fasteners located within the cavities, and (2) a circuit conductor pattern on a second side facing away from the base, the conductor pattern including a plurality of conductor pairs corresponding in number to the apertures through the board, each conductor pair straddling one of the apertures in the board; and a plurality of wide-headed contact screws inserted into each of the apertures in the board and extending through the board into locking engagement with the apertures of the fasteners, the head of each screw adapted to make contact with both conductors of the corresponding pair of conductors for establishing electrical continuity between such pair of conductors.

3. An assembly comprising: a base having a plurality of cavities located according to a defined pattern in one surface thereof; an array of fasteners, interconnected by runners into a self-supporting structure, the fasteners located in accordance with the defined pattern in the cavities; a circuit board located with one surfacE thereof contiguous to the fasteners, the other surface of the board having a plurality of pairs of conductors thereon; and a plurality of screws inserted through the board into the fasteners, the screws adapted to establish electrical continuity between the conductors of each pair of conductors.