US3574919A

US3574919A - Methods of and apparatus for assembling articles

Info

Publication number: US3574919A
Application number: US816966A
Authority: US
Inventors: Miles N Reppert
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1969-04-17
Filing date: 1969-04-17
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13

Abstract

Groups of elongated paramagnetic articles, having headed ends, are aligned with and moved through groups of bores in an assembly fixture after which washers are placed over the ends of the elongated articles. The assembly fixture is inverted and the washers slide along the articles into engagement with the headed ends of the articles and are held thereagainst when the fixture is returned to an original position. The lower unheaded ends of the articles are positioned in holes formed in a wafer after which the elongated articles are released to drop slideably in the holes in the wafers until the washers engage the top surface of the wafer.

Description

United States Patent Appl. No. Filed Patented Assignee METHODS OF AND APPARATUS FOR ASSEMBLING ARTICLES 10 Claims, 20 Drawing Figs.

US. Cl 29/429, 29/203, 29/469, 29/592, 29/625, 228/6 Int. Cl ..B23p 19/00, HOSk 13/00, B23p 21/00 Field of Search 29/429,

203, 469, 592, 203 (MW), 203 (MM), 203 (P), 625;228/6 [56] References Cited UNITED STATES PATENTS 3,243,180 3/1966 Van Ryn 29/464X 3,465,435 9/1969 Steranko 29/469X Primary ExaminerThomas H. Eager Att0rneys-l-l. J. Winegar, R. P. Miller and R. Y. Peters ABSTRACT: Groups of elongated paramagnetic articles, having headed ends, are aligned with and moved through groups of bores in an assembly fixture after which washers are placed over the ends of the elongated articles. The assembly fixture is inverted and the washers slide along the articles into engagement with the headed ends of the articles and are held thereagainst when the fixture is returned to an original position. The lower unheaded ends of the articles are positioned in holes formed in a wafer after which the elongated articles are released to drop slideably in the holes in the wafers until the washers engage the top surface of the wafer.

Patented April 13, 1971 3,5 74,91 9

4 Sheets-Sheet 5 a 7/5 3 ,/5 as (1/ Y/I/ A/ w 46 3/ /5 ecu 5 a:

#1 g= SH 72 F1 g-sa 1 METHODS OF AND APPARATUS FOR ASSEMBLING ARTICLES BACKGROUND OF THE INVENTION l. Field of the Invention This invention relates to methods of and apparatus for assembling articles, and more particularly, to methods of and apparatus for simultaneously threading a plurality of groups of elongated paramagnetic leads individually through washers and then assembling the lead-washer subassemblies to wafers.

2. Prior Art and Technical Considerations In the manufacture of small electronic components, such as semiconductor diodes, it is frequently desirable to mount the components on support structures which are commonly referred to as headers. Each header consists of a waferwasher-lead subassembly and a flanged cup-shaped ring to which the subassembly is brazed by means of a brazing washer. The subassembly includes a metallized-ceramic wafer to which one or more paramagnetic, headed leads and small brazing washers are assembled.

Brazing washers are mounted on the leads and then the unheaded ends of the leads are inserted through openings provided in the ceramic wafer. Since the openings in the wafer are large enough to pass the elongated portion of the leads but not the brazing washers or the heads of the leads, the brazing washers are sandwiched between the metallized surface of the ceramic wafer and the heads of the leads. When another brazing washer is added to a flange and a properly oriented subassembly placed on top, the combination can be processed through an appropriate brazing furnace at the proper temperature for a suitable length of time, to braze the leads and flange to the metallized-ceramic wafer, thus forming a header.-

Present methods of assembling the leads to the ceramic wafers include mounting the brazing washers on the leads by hand and then threading the lead and washer assemblies individually through the openings in the ceramic wafers. This is a relatively slow, laborious, and costly process.

Summary of the Invention Accordingly, an object of this invention is to provide new and improved methods of an apparatus for subassembling a plurality of groups of elongated articles through individual washers, and for then assembling each group of articles to a wafer.

With these and other objects in mind, this invention contemplates dropping paramagnetic elongated articles through bores in an assembly fixture after which individual washers are threaded over the articles and held in the vicinity of the headed ends of the articles when the assembly fixture is inverted to position the unheaded ends of the articles in apertures formed in a predetermined pattern in a wafer whereafter the articles are released to drop downwardly until supported against the top surface of the wafer.

More particularly, a mass of elongated paramagnetic articles having one end headed are held in spaced, parallel relation in a plurality of groups in a predetermined pattern in a loading fixture above a plurality of groups of bores in an assembly fixture. The articles are passed through the bores until the headed ends are held by a locking plate to retain the elongated articles in the assembly fixture while the assembly and loading fixtures are inverted in unison.

Then a tray having a plurality of groups of washers arranged in the predetermined pattern coincident with the articles is placed below the unheaded ends of the articles. A magnet is positioned above the assembly fixture to hold the headed ends of the elongated paramagnetic articles a predetermined distance above the locking plate, and against a support plate which is interposed between the magnet and the locking plate. In this way, the lower ends of the elongated articles do not protrude from the assembly fixture and bending of the leads is precluded. Moreover, the leads cannot interfere with the alignment of the assembly fixture and a washer loading tray.

The magnet is then removed and the assembly fixture and the washer tray are vibrated in unison to urge the end of each of the elongated articles into a washer. The support plate is replaced with a retaining plate; after which the fixture and tray are inverted to drop the washers through the bores of the assembly fixture and against the undersides of the heads of the elongated articles. The retaining plate maintains the shank portions of the elongated articles in the washers and the elongated articles in the bores of the assembly fixture, during inversion of the fixtures. Both the elongated articles and the washers are held in the assembly fixture by the locking plate upon reinversion of the assembly fixture.

A plurality of ceramic wafers, each having a group of openings formed therein in the predetermined pattern, are aligned with the elongated articles in the assembly fixture. The magnet and support plate are repositioned above the assembly fixture to attract and hold the headed ends of the elongated articles against the support plate so that the lower ends of the elongated articles do not protrude from the assembly fixture and interfere with the positioning and aligning of the ceramic wafers in a loading tray. Then, the magnet is removed and the assembly fixture and loading tray are vibrated in unison until the end of each elongated article is moved into one of the openings in the aligned wafers. The support plate is replaced with the retaining plate on the assembly fixture to maintain the unheaded ends of the elongated articles in the wafer holes; then the assembly fixture and loading tray are inverted in unison and slightly vibrated to urge the wafers to slide downwardly along the elongated articles and into engagement with the assembly fixture. A second locking plate is used to retain the ceramic wafers in engagement with the assembly fixture when the assembly fixture is reinverted to the original position.

Then the retaining plate is removed and the support plate and magnet are repositioned 0n the assembly fixture. The assembly fixture is inverted and then reinverted whereupon the elongated articles are held up against the support plate so that the lower ends of the elongated articles do not protrude from the assembly fixture. The assembly fixture is placed over a brazing fixture having openings which are aligned with the elongated members in the assembly fixture. The locking plates are moved slidably to release and drop the articles vertically downward until the washers and headed ends are supported on the wafers and the wafers are supported on the brazing fixture.

Other objects, advantages, and features of the invention will be apparent when taken in conjunction with the accompanying drawings.

Brief Description of the Drawings FIG. 1 is an exploded perspective view of a plurality of headed leads, washers and a ceramic wafer which are assembled together by the principles of the method of this invention to form a header subassembly;

FIG. 2 is a perspective view partially in section of a header subassembly including one metallized-cerarnic wafer, a plurality of leads and brazing washers which are assembled by the principles of the method of the present invention;

FIG. 3A is a perspective view of an assembly fixture which may be used to practice the steps of the method of this invention to assemble a plurality of the header subassemblies, partially in section to show a detail view of a portion of the assembly fixture with one of a plurality of guide bores in a body member of the fixture;

FIG. 3B is a detailed perspective view of a portion of a locking plate and showing one of a plurality of keyhole-shaped openings formed therein;

FIG. 4A is a partial section of a lead loading fixture having a loading plate with a configuration of openings which coincides with the arrangement of bores in the assembly fixture shown in FIG. 3A, and having magnetic facilities for aligning a mass of leads for loading into the loading plate;

FIG. 4B is a partial section of the lead loading fixture shown in FIG. 4A with the leads drawn through the openings in the loading plate;

FIG. 5A is a partial cross-sectional view taken along line 5-5 in FIG. 3A and showing the leads in the loading plate ositioned below the assembly fixture with the leads aligned with the bores in the assembly fixture;

FIG. 5B is the same partial cross-sectional view of the assembly fixture in an inverted position and showing the leads passed through the bores in the assembly fixture until the headed ends thereof engage a retaining plate positioned below the body member of the assembly fixture;

FIG. 5C is the same partial cross-sectional view of the assembly fixture, reinverted, with the lead-loading plate removed and showing the leads held in the assembly fixture by a locking plate;

FIG. 6A is a partial cross-sectional view, taken along line 5-5 of FIGS. 3A, of a tray of washers positioned below the assembly fixture with each of the washers aligned with one of the bores in the body member of the assembly fixture;

FIG. 6B is the same partial cross-sectional view of the assembly fixture and showing the lower ends of the leads inserted into the washers in the tray;

FIG. 6C is the same partial cross-sectional view showing the assembly fixture in an inverted position with the washers having descended through the bores in the body member and now in engagement with the headed ends of the leads;

FIG. 7 is a partial cross section, taken along line 5-5 of FIG.

3A, showing the leads with the washers threaded thereon retained by a locking plate in the assembly fixture;

FIG. 8A is a partial cross-sectional view, taken along line 5-5 in FIG. 3A, of a tray holding a plurality of ceramic wafers positioned below the assembly fixture with each of the wafers aligned with a group of the leads, which are held above the wafer by a magnet;

FIG. 8B is the same partial cross-sectional view of FIG. 8A showing the magnet removed and the leads in a descended position with the end of the leads inserted in openings in the ceramic wafer;

FIG. 8C is the same partial cross-sectional view as in FIG. 8A showing the assembly fixture and wafer tray in an inverted position with the wafer having dropped through an opening in a locking plate and now in engagement with the body member of the assembly fixture;

FIG. 9 is a plan view of one cavity of the ceramic-wafer loading tray as viewed along line 9-9 of FIG. 8A;

FIG. 10A is a partial cross-sectional view, taken along line 5-5 of FIG. 3A, of the assembly fixture showing leads held in a suspended position by the magnet above a brazing fixture;

FIG. 10B is a partial cross-sectional view of the assembly fixture shown in FIG. 10A with the magnet removed and the leads and washers descended into engagement with the wafers; and

FIG. 10C shows the wafer-lead-washer subassembly moved from the assembly fixture and seated in the brazing fixture.

DETAILED DESCRIPTION General Referring to FIG. 1, four nonmagnetic washers 11 are assembled on four paramagnetic leads 12 having headed ends 15, and then each of the leads is inserted in an aperture 13 in a ceramic wafer 14. The ceramic wafer 14 has metallized surfaces 16, which have been plated, and a notch 17 formed in a peripheral edge thereof in a predetermined relation to the pattern of the apertures 13 and the metallized surfaces. The wafer 14 together with the leads l2 and washers 11 are referred to as a subassembly, designated generally by numerals 18, (see FIG. 2) which is subsequently positioned on another subassembly, which includes a flange 82 (see FIG. 10A) and brazing washer 83 (see FIG. 10A), in preparation for a brazing operation.

Assembly Fixture Referring now to FIG. 3A, an assembly fixture, designated generally by the numerals 19, includes a transfer or body member 20 to which side members 22 are fastened. The body member 20 includes a lower portion 21 and an upper portion 21, which are fastened together and which are formed with a plurality of aligned bores 23 and 23, respectively, arranged in patterns of four, aligned with the leads 12 in the subassembly 18 (see FIG. 5A). The bores 23 and 23' are formed with a small diameter portion 24 (see FIG. 5A) which opens to a bottom surface of the bottom portion 21 of the body member 20 and a small diameter portion 24' which opens to a top surface of the upper portion 21' of the body member. The small diameter portions 24 and 24' are larger than the diameter of the headed end 15 of the lead 12 and of the washer 11. Also, the

smaller diameter portions

24 and 24 are joined to the

bores

23 and 23 by tapered sections 26 and 26', respectively (see FIG. 5A). The tapered sections 26 and 26' and

smaller diameter portions

24 and 24 accurately locate the washers 11 and leads 12 while permitting the washers and leads with moderate camber to slide through the bores without binding to the walls of the bores.

In order to retain the leads 12 within the bores 23-23' of the body member 20, an upper locking plate 27 is slideably mounted in upper grooves 28 formed in the side members. The upper locking plate 27 is formed with a plurality of groups of keyhole-shaped openings 29 (see FIG. 38) having circular portions 31 and slotted portions 32. The locking plate 27 is initially positioned so that circular portions 31 of the keyhole openings are aligned with the bores 23-23' in the body member 20. The circular portions 31 of the keyhole openings 29 are slightly larger than the headed ends 15 of the leads l2 and the washers 11. The smaller dimension of the slotted portions 32 of the keyhole openings 29 is less than the diameter of the headed end 15 of the leads 12 or the washers II, but slightly greater than the diameter of the elongated portion of the leads. The upper locking plate 27 may be moved slideably in either direction (see FIG. 3A) to align either the circular portion 31 or the slotted portion 32 of the keyhole-shaped openings 29 with the bores 23-23.

In order to prevent the leads 12 from dropping out of the fixture when the fixture I9 is inverted during the method of practicing this invention, a retaining plate 33, having four ears 34 projecting therefrom, is secured on the top of the assembly fixture 19 by four tongues 36 which are formed integrally with the side members 22. The retaining plate 33 may be removed and replaced as needed by sliding the retaining plate far enough to the right as viewed in FIG. 3A to clear the tongues 36. v

The raising of the leads 12 in the bores 23-23' is accomplished with the assistance of a support plate 37, and a magnet 38 in engagement with the support plate. The support plate 37 is formed with four ears 39 which are positioned under the tongues 36 and which permit the support plate to be removed and replaced along with the magnet 38, or retained on top of the assembly fixture 19. Additionally, the support plate 37 is formed so that a lower surface thereof is spaced above the upper locking plate 27 a distance greater than the upper surface of the retaining plate 33. Hence, the distance between the upper locking plate 27 and the support plate 37, when the support plate is in position, is greater than that between the upper locking plate 27 and the retaining plate 33 when the retaining plate is in position.

A second or lower locking plate 41 is used in the manipulation of the wafers 14. The lower locking plate 41 has slotted keyhole-shaped openings 42 formed therein and is mounted slidably in lower grooves 43 cut in the side members 22. The center of a circular portion 44 of the openings 42, is aligned with a center of each cluster of four of the bores 23-23 in the body member 20. Also, the circular portion 44 of the openings 42 is slightly larger than the diameter of the ceramic wafers l4, and the smaller dimension of a slotted portion 46 is slightly greater than the diameter of the elongated shank portion of a lead 12.

Loading Fixture Prior to assembling the header subassembly 18 in the assembly fixture 19, it is necessary to preload a mass of the leads 12, by methods known in the art such as a vibratory technique into a loading fixture 51 (see FIG. 4A). Referring now to FIGS. 4A and 4B, the loading fixture 51 includes a base or load plate 52 having a plurality of bores 53, a shuttle plate 54, having openings 56, and support rails 57. The bores 53 and openings 56 in the base plate 52 and the shuttle plate 54, respectively, are congruent with the bores 23-23 in the body member of the assembly fixture 19. Also, the

openings

53 and 56 in the base plate 52 and shuttle plate 54, respectively, are larger than the diameter of the elongated portion of the lead 12. Moreover, the openings 56in the shuttle plate 54 are less than twice the diameter of the lead 12 so that only one lead may be positioned in each opening.

In loading the leads 12, a random mass of leads is placed in a boxlike enclosure 58 constructed of nonmagnetic material, e.g., plastic or aluminum. The loading fixture 51 which includes the shuttle plate 54 is placed over the enclosure 58 to trap the leads 12 between the enclosure and the shuttle plate. Then, the loading fixture 51 and enclosure 58 are inverted as a unit and positioned in a magnetic field established between upper and

lower magnets

61 and 59, as shown in FIGS. 4A and 48, with the support rails 57 of the loading fixture 51 resting on the lower magnet 59. The enclosure 58 and the loading fixture 51 are moved in unison back and forth, horizontally, by imparting vibratory motion thereto until the mass of elongated paramagnetic leads are disentangled and then supported in parallel, spaced relation along the magnetic lines of forces established between the

magnets

59 and 61. Moreover, since the distance between the leads 12 and the magnet 59 is less than the distance between the leads and the magnet 61, the leads are attracted to the lower magnet 59.

The leads 12 are confined in the space between the enclosure 58 and the plate 54 to prevent the formation of chains of leads which could undesirably bridge the gap between the upper and

lower magnets

59 and 61 and prevent all the leads 12 from migrating toward the lower magnet 59. The sidewalls of the enclosure 58 also prevents the leads 12 from migrating laterally due to repulsive forces of like magnetic poles at opposite ends of the leads when a large quantity of leads are placed in the enclosure 58.

Initially, the shuttle plate 54 is positioned, as shown in FIG. 4A, to prevent the leads 12 from entering prematurely the openings 53 in base plate 52 of the loading fixture 51 and to permit untangling and alignment of the leads in the magnetic field between the shuttle plate and the enclosure 58. The openings 56 in the shuttle plate 54 are countersunk so that the ends of the leads l2 tend more easily to locate in these openings. A cluster of the aligned leads 12 congregate about each of the openings 56 in the shuttle plate 54. Moreover, since the entrance of the openings 56 in the shuttle plate 54 are beveled, the leads 12 may pivot due to the movement of the mass of the leads. Otherwise, if one end of a lead 12 were to jam in an opening in the shuttle plate 54 while the other end was forced to move by a mass of clustered leads therearound during the back and forth motion of the fixture 51 and enclosure 58, the lead, restrained at one end, would bend and be damaged.

An initial group of the leads 12 is urged through the bores 53 and openings 56in the loading fixture 51 by a combination of gravitational and magnetic forces. After the leads 12 are untangled and aligned with the magnetic .lines of force with leads positioned in random holes 56 in the shuttle plate 54. the shuttle plate is moved slideably over the base plate 52 until the openings 56 in the shuttle plate are aligned with the bores 53 in base plate 52. The leads 12 are attracted toward the lower magnet 59 to move the lower ends of the leads which are already in the holes 56 of the shuttle plate into the loading fixture 51 (see FIG. 4B) so that the headed ends 15 are supported on a top surface of the shuttle plate 54. Further horizontal oscillation of the loading fixture 51 together with the enclosure 58, pass the elongated shanks of the leads 12 onto the countersunk portions of the unfilled holes and through the loading fixture 51 until the heads of the leads engage the shuttle plate 54.

The loading fixture 51, now loaded with the leads 12 is withdrawn along with the enclosure 58 from the magnetic field between the

magnets

59 and 61. Since the openings 56in the shuttle plate 54 are smaller than the diameter of the headed ends of the leads 12, the leads do not fall through the loading fixture 51 when the loading fixture is withdrawn from between the magnets.

As an alternate embodiment, a backup plate 67 may be added to permit loading articles which do not have headed ends 15 by positioning the backup plate close enough to the bottom of the loading fixture 51 to prevent the articles from passing therethrough. Otherwise articles 12 without heads would not be trapped in the assembly fixture as hereinbefore described.

In order to assume an orderly transfer of the leads 12 from the loading fixture to the assembly fixture, an alignment plate 62 is positioned in engagement with the shuttle plate 54 so that locating pins 63 on the alignment plate are received in cavities 64 in the shuttle plate (see FIG. 5A). In this way a plurality of stepped bores 66 in the alignment plate 62 are aligned with the bores 53 in the base plate 52 of the loading fixture 51 and the bores 23-23' in the assembly fixture 19 to guide the leads 12 when the leads are moved from the loading fixture into the assembly fixture.

Method of Assembly Referring now to FIGS. 5A, 5B, and 5C, the fixture 51, with the enclosure 58 removed, is positioned beneath the assembly fixture 19 with the support plate 37 inserted above the body member 20 and with the bores 53 and openings 56 in the loading fixture aligned with the bores 23-23 in the assembly fixture. The circular portions of the openings in the upper and

lower locking plates

27 and 41, respectively, are also aligned with the

bores

23 and 23 in the assembly fixture 19 and the bores 53 and openings 56 in the loading fixture 51 to permit free passage therethrough of the leads 12.

The

fixtures

19 and 51 are inverted, in un son, to permit the leads 12 to move through the bores 66 in the alignment plate 62 and the fixture 19 under the urging f gravitational force until the headed ends 15 seat against the support plate 37 as shown in FIG. 5B. The magnet 38 is then placed in engagement with the support plate in preparation for the next sequence of steps. The loading fixture 51 is removed and the upper locking plate 27 is moved to the left, as viewed in FIG. SE, to shift the slotted portion 32 of the keyhole openings 29 over the headed ends 15 of the leads 12.

Referring to FIG. 5C, it can be seen that if it were necessary to interrupt the operation at this point, and the fixture reinverted, the leads 12 would drop away from the support plate 37 until the headed ends 15 engage the locking plate 27. Since the headed ends 15 cannot pass through the slotted portions 32 of the keyhole openings 29, the leads 12 are retained in the fixture. However, in the uninterrupted practice of the method of this invention, the assembly fixture 19 is retained in an inverted position and the magnet 38 is placed in engagement with the support plate 37 to hold the leads 12 up against the bottom of the support plate 37 when the assembly fixture 19 is reinverted, as shown in FIG. 6A, in preparation for the threading of the washers 11 on the leads.

In the next sequence of steps in carrying out the method of this invention, as shown in FIGS. 6A, 6B, and 6C, washers 11 are threaded over the shank portions of the leads 12. While the leads are held in the position shown in FIG. 6A, a tray 68 having stepped bores 69, is loaded by manual and vibratory techniques to seat a washer 11 on an annular surface 71 of each of the stepped bores. Then the tray 68 is positioned beneath the assembly fixture 19 with the stepped bores 69 aligned with the bores 23-23 in the assembly fixture. The magnet 38 and support plate 37 are removed from the assembly fixture 19 whereupon the leads 12 drop vertically to move the ends of the leads l2 partially through the washers 11 in the washer tray 68 (see FlG. 6B). The assembly fixture 19 and the washer tray 68 are vibrated in unison while maintaining the aligned relationship therebetween until all the leads 12 are partially threaded through the washers 11. Because the upper locking plate 27 is positioned with the slotted portions 32 of the keyhole slots 29 aligned with the bores 23- 23, the leads 12 do not drop all of the way through the assembly fixture 19, but remain suspended by the heads engaging the upper locking plate 27.

Then the retaining plate 33 is positioned above the locking plate 27 in preparation for the assembly of the washers 11 on the shank portions of the leads 12. The assembly fixture 19 and the tray 68 are inverted in unison and the locking plate 27 is shifted to the right, as viewed in H0. 6C, to align the circular portions 31 of the keyhole openings 29 with the bores 23-23 in the body member 20. The washers 11 drop vertically and slide along the shank portions of the leads 12 through the keyhole openings 42 in the lower (now upper) locking plate 41, through the bores 23-23 in the body member 20, and through the keyhole openings 29 in the upper (now lower) locking plate 27 into engagement with the headed ends of the leads 12 as shown in FIG. 6C. When the washers 11 are in engagement with the heads of the leads 12, the upper (now lower) locking plate 27 is moved slidably to the left as viewed in FIG. 6C to trap the washers and the headed ends of the leads between the retaining plate 33 and the plate 27. The tray 68 is then removed and the assembly fixture 19 reinverted whereupon the leads 12 and washers drop vertically until washers 11 engage and are supported on the locking plate 27 (see FIG. 7).

Referring now to FIG. 8A, the ceramic wafers 14 are loaded into a tray 72 by vibratory techniques well known in the art. The tray 72 has a plurality of cavities 73, each of which is aligned with the center of a cluster of the bores 23-23 in the body member 20. A pin 74 is press fitted in the tray 72 astride the edge of each of the cavities 73 (refer to HO. 9) to cooperate with the notches 17 in the ceramic wafers 14 to orient the openings 13 in the wafers with bores 76 formed in the ceramic-wafer tray 72. The bores 76 in the tray 72 which open into the cavities 73, are dimensioned to receive the elongated portions of the leads [2 and are aligned with the bores 23-23' in the body member of the assembly fixture 19. In addition, ports 77 are formed in the tray 72 and open into the centers of the cavities 73. The ports 77 are connected to a source of vacuum (not shown) to apply a vacuum to the underside of each of the ceramic wafers 14. The vacuum retains the ceramic wafers 14 in the cavities 73 after the wafers have been vibrated into position in the cavities.

In the next sequence of steps, each of the wafers 14 is threaded over the end portions of a group of the leads 12. Referring now to FIG. 8A, the retaining plate 33 is replaced with the support plate 37 and magnet 38. The assembly fixture 19 is inverted and the leads 12 are urged by gravitational and magnetic forces into engagement with the plate 37 to hold the leads 12 above a lower surface of the locking plate 41 when the assembly fixture 19 is reinverted. Then the tray 72 can be positioned beneath and aligned with the assembly fixture 19 without bending any leads. Then the magnet 38 is removed and the assembly fixture l9 and the tray 72 are vibrated in unison to urge the leads 12 into and through the apertures 13 in the ceramic wafers 14. The leads 12 are arrested when the heads of the leads engage the locking plate 27. The plate 37 is removed and replaced with the retaining plate 33 (see FlG. 88). Subsequently, the assembly fixture 19 and the ray 72 are inverted as a unit, whereupon the ceramic wafers 14 slide along the leads 12 and drop through the keyhole openings 42 in the locking plate 41 until the wafers are supported on a surface of the portion 21 of the body member 20 (see FIG. 8C). When all of the ceramic wafers 14 are supported on the body member 20, the locking plate 41 is moved to the left as viewed in FIG. 8C to misalign the circular portions 44 of the keyhole openings 42 with the ceramic wafers 14 to trap the ceramic wafers between the locking plate 41 and the body member 20 ofthe assembly fixture 19.

Next, the leads 12 are assembled to the wafers 14 to support the headed ends 15 of the leads on the wafers. As can best be seen in FIGS. 10A, 10B, and 10C, the tray 72 is removed and the assembly fixture 19 is reinverted. The retaining plate 33 is replaced by the plate 37 and the magnet 38 so that the leads 12 can be attracted to and held in engagement with the underside of the magnet plate 37. In this position, the leads 12 protrude through the ceramic wafers 14 but do not protrude below locking plate 41 to facilitate alignment with a brazing fixture 78 without bending any leads. If necessary, the assembly fixture 19 may again be inverted to apply gravitational forces to the leads to insure that the leads are in engagement with the support plate 37, after which the fixture 19 is reinverted to the position shown in FIG. 10A.

The brazing fixture 78 has a plurality of bores 79 which are aligned with the bores 23-23 of the body member 20 to receive the leads 12. The bores 79 open to a plurality of larger cavities 81, the centers of which are coincident with the centers of the clusters of bores 23-23'. Moreover, each of the cavities 81 is preloaded with a flange 82 and a brazing preform 83. The brazing fixture 78, which is made of material suitable for use in high temperature furnaces, is aligned with the assembly fixture 19, and the upper locking plate 27 is shifted to the right as viewed in FIG. 10B to align the circular portions 31 of the keyhole openings 29 with the bores 23-23' and permit the washers 11 and the leads 12 to drop through the body members 20 of the assembly fixture 19 until the washers 11 engage the ceramic wafers 14. Then the lower locking plate 41 is shifted to the right, as viewed in FIG. 108, to align the circular portions 44 of the keyhole-shaped openings 42 with the cavities 81 in the brazing fixture 78. The subassemblies 18, consisting of the washers 11, leads 12, and ceramic wafers 14 drop onto the brazing fixture 78 to complete the assembly of the units and the transfer of the units to the brazing fixture as shown in FIG. 10C. The assembled units, each consisting of flange 82, preform 83, wafer 14, washers 11, leads 12, are now placed in a furnace to bond the subassembly 18 to the flange and the leads 12 to the wafer 14.

lclaim: I

1. ln a method of assembling elongated articles to discshaped articles each having an aperture formed therethrough:

supporting an array of said elongated articles in parallel relationship with each other;

positioning a like array of said disc-shaped articles below the ends of said elongated articles; inserting the ends of said elongated articles into said apertures in said disc-shaped articles; and

inverting said elongated articles and said disc-shaped articles to slide said disc-shaped articles along said elongated articles.

2. A method of assembling a paramagnetic pin having a headed end through a washer and into a aperture formed in an article, which comprises:

magnetically holding the headed end with the pin depending toward and aligned with the washer;

releasing the magnetic force to drop the pin into the aperture; inverting the pin to seat the washer against the headed end; again inverting the assembled pin and washer; and again magnetically holding the head with the pin depending toward and aligned with the aperture in the article;

supporting the washer in a position spaced from the headed end a distance greater than the distance between the depending end of the pin and the aperture;

releasing the magnetic force to drop the pin through the supported washer to move the depending end into the aperture; and then releasing the washer todrop the pin into the aperture and move the washer into engagement with the article.

3. ln a method of assembling a group of washers and a wafer with a like group of holes therethrough onto shanks of a group of headed leads:

supporting the headed leads with the shanks thereof depending downwardly;

positioning a group of washers in alignment with said shanks of said leads;

releasing said headed leads to move depending ends of the shanks partially through said washers;

inverting the leads and washers to move the washers along the shanks to engage the heads on the leads;

repositioning the leads and washers to support the heads with the shanks depending downwardly while holding the washers in the vicinity of the heads; positioning said wafer below said leads with the holes therein aligned with the depending ends of the shanks;

releasing the leads to move the heads into engagement with the washers while the ends of the shanks move through the aligned holes in the wafer;

inverting the washers, leads, and wafer to move the wafer a predetermined distance along the group of the leads; reinverting the washers, leads, and wafer; and

releasing the washers to drop the shanks through the wafer and move the washers into engagement with the wafer.

4. In a method of assembling each of a group of leads each having a headed end and an unheaded end, through a washer and then with an article having a group of apertures arranged in a predetermined pattern:

supporting said group of leads in parallel relationship with each other and arranged in said predetermined pattern, with said headed ends oriented upwardly;

positioning a group of washers arranged in said predetermined pattern below the unheaded ends of said leads with each of said washers aligned with one of said leads;

releasing said leads to move the unheaded ends of said leads into said washers;

inverting said leads and said washers to slide said washers along said leads and into engagement with said headed ends;

reinverting said leads while holding the leads with said headed ends aligned in a plane;

supporting the washers spaced a predetermined distance from the headed ends of the leads;

placing said article below the unheaded ends of said leads a distance less than said predetermined distance while aligning said apertures with said leads; releasing said leads to move the headed ends of the leads through said predetermined distance into engagement with the washers and move the unheaded ends of the leads into the apertures in said article; and v releasing said washers to move said washers and leads in unison relative to said article to thread said leads through said apertures and support said washers and said leads against said article.

5. A method of assembling a group of headed leads, a group of washers, and a pair of members having a pattern of apertures formed therethrough, each of said apertures being larger than the shank of a lead but smaller than the head of a lead;

supporting a group of leads in a pattern corresponding to said pattern of apertures with the unheaded ends of the leads extending downwardly; positioning a group of washers in a pattern corresponding to the pattern of leads beneath and spaced from said leads; releasing the leads to partially drop through said washers; inverting the washers and leads to slide the washers against the headed ends of the leads; reinverting the leads;

supporting the washers and the leads with the headed ends a predetermined distance from the washers;

supporting a first member with the apertures aligned with the unheaded ends of the leads and at a distance which is less than said predetermined distance; releasingthe leads to drop said unheaded ends into said apertures of said first member;

supporting said washers and said headed ends to retain the leads partially extending through the apertures in said first member;

supporting a second member with the apertures aligned with said partially extending leads;

releasing said washers and leads to drop said leads through said apertures in the first member into the apertures in said second member where the leads are maintained in position by engagement of the washers with the top surface of said first member; and

releasing said first member to advance into engagement with the second member and move said leads through said apertures.

6. In a method of assembling a plurality of predetermined groups of paramagnetic leads, each lead having a headed end and an unheaded end, with a plurality of groups of washers and a plurality of wafers each having a predetermined pattern of apertures:

magnetically positioning and then supporting a plurality of groups of said leads in patterns, each of which corresponds to said predetermined pattern, in an initial position with the longitudinal axes of said leads parallel and the headed ends oriented upwardly;

moving and then holding said leads to align the heads of said leads in a plane;

placing a plurality of groups of washers, each arrayed in said predetermined pattern, below and aligned with the unheaded ends of said leads;

releasing said leads to drop and move the lower unheaded ends of the leads through said washers;

inverting said leads to slide the washers along said leads and into engagement with the headed ends thereof; magnetically holding said headed ends in a plane; reinverting said leads to the initial position to slide said washers along said leads;

supporting said washers a predetermined distance out of engagement with said headed ends;

aligning a plurality of wafers a distance less than said predetermined distance beneath the unheaded ends of said leads with the apertures in said wafers aligned with said unheaded ends of said leads;

releasing said leads to drop said prede ermined distance to support said headed ends in ezgagement with said washers and to move said lower unheaded ends through said apertures in said wafers;

inverting said leads and wafers to slide said wafers along said leads;

holding said wafers spaced from the unheaded ends of the leads; and

releasing said washers to drop said washers and said leads into engagement with said wafers.

7. A method of loading an array of paramagnetic pins in a fixture for subsequent processing, each of said pins having a headed end and an unheaded end, wherein the fixture comprises a first horizontal plate having a first array of holes therethrough and a second plate overlying the first plate and having a second, like array of holes therethrough, each of said holes in the second plate being smaller than the headed end of a pin, which comprises:

moving one plate relative to the other to move the holes out of alignment;

placing a mass of paramagnetic pins on the second plate;

applying a magnetic field transversely of the plates to vertically suspend the pins with lower ends thereof bearing against the second plate;

imparting relative movements between said plates and said suspended pins to move the unheaded ends of certain of said pins into the holes in the second plate; and

moving one plate relative to the other to move the holes into alignment to permit those pins positioned in the holes in the second plate to pass through the holes in the first plate and be retained by the headed ends engaging the top surface of the second plate.

8. in an arrangement of apparatus for assembling a washer onto a shank of a pin having a headed end:

a frame having a pair of spaced vertical end plates;

a first plate having a slot for receiving the shank of the pin and supporting the headed end, said slot being narrower than the diameter of the headed end and the washer;

means for slideably supporting said first plate between said end plates with the shank of the pin extending in a downward direction;

means for lifting the pin in the slot and then releasing the means for supporting a washer in the space vacated by the lifted pin and in position to receive the released pin; and

a second plate slideably mounted between said end plates for retaining the pin in the slot upon inversion of the frame, said first plate having a bore extending therethrough at one end of said slot, said bore being larger than the washer and positioned by sliding the first plate to pass said washer along said shank into engagement with said headed end;

9. In an assembly fixture for assembling a plurality of groups of paramagnetic leads supported in parallel spaced relation, each of said leads having headed and unheaded ends, with a plurality of groups of washers and then with a plurality of wafers each having a predetermined pattern of apertures:

a transfer member having a plurality of groups of bores formed therethrough for guiding said leads, each of said groups arranged in said predetermined pattern;

means movably mounted for magnetically supporting a group of said leads in an initial position to align said headed ends in a plane with said unheaded ends depending downwardly into said groups of bores;

a locking plate interposed between said supporting means and said transfer member and having a plurality of groups of keyhole-shaped openings formed therein and arranged in said predetermined pattern, with a circular portion of each of said openings aligned initially with one of the bores in said transfer member for receiving said groups of leads, said keyhole opening having a slotted portion which is narrower than the diameter of the headed end and the washer;

means mounting said locking plate for sliding movement to position slotted portions of said keyhole openings over said bores in said transfer member and to confine said washers and said headed ends between said locking plate and said supporting means;

means for holding said plurality of groups of washers below the unheaded ends of said leads with each of said groups of washers arranged in said predetermined pattern and with each of said washers aligned with one of said bores in said transfer member;

a second locking plate, having a plurality of openings formed therein, said second locking plate interposed between said holding means and said transfer member for guiding said wafers into engagement with a bottom surface of said transfer member when said fixture is inverted, each of said openings in said plate having a slot extending radially therefrom, said slot being narrower than the diameter of a wafer; and

means mounting said plate for sliding movement to lock said wafers against said transfer member and to permit one lead of each of said groups to be received in one slot before said fixture is returned to the initial position.

10. In a fixture for assembling a plurality of groups of paramagnetic leads, each of said leads having headed and unheaded ends, with a plurality of groups of washers, and then with a plurality of wafers, each having a predetermined pattern of apertures, said leads held initially in parallel, spaced relation with said headed ends orientedupwardly:

a transfer member having a plurality of groups of bores formed therethrough, each of said groups having said bores arranged in said predetermined pattern;

magnetic means for supporting said leads with said headed ends aligned in a plane and with said unheaded ends received in said bores in said transfer member;

a first locking plate interposed between said magnetic means and said transfer member and having a plurality of groups of keyhole-shaped openings formed therein and arrayed in said predetermined pattern with a circular portion of said openings aligned with the bores in said transfer member, and with slotted portions of said openings being narrower than said washers and said unheaded ends;

means mounting said first locking plate for sliding movement to position the slotted portions of said keyhole openings over said bores in said transfer member and to confine said washers and said headed ends between said locking plate and said magnetic means;

means for holding said plurality of groups of wafers arranged in said predetermined patterns below the unheaded ends of said leads with each of said washers aligned with one of said leads;

a second locking plate having a plurality of openings and interposed between said wafers and said transfer member for passing said wafers to slide along the unheaded ends of said leads and against the bottom surface of said transfer member when said fixture is inverted, each of said openings aligned initially with one of said groups of bores in said transfer member and having a slot formed therein radially extending therefrom, each of said slots being narrower than the wafer and larger than the diameter of the unheaded end of the lead;

a retaining plate slideably mounted between said magnetic means and said first locking plate for engaging and holding the leads in the transfer member when said fixture is inverted; and

means for slideably mounting said second locking plate to shift said second locking plate to lock said wafers against said transfer member and to permit one lead of each of said groups of leads to be received in one slot before said fixture is returned to said initial position.

Claims

1. In a method of assembling elongated articles to disc-shaped articles each having an aperture formed therethrough: supporting an array of said elongated articles in parallel relationship with each other; positioning a like array of said disc-shaped articles below the ends of said elongated articles; inserting the ends of said elongated articles into said apertures in said disc-shaped articles; and inverting said elongated articles and said disc-shaped articles to slide said disc-shaped articles along said elongated articles.

2. A method of assembling a paramagnetic pin having a headed end through a washer and into a aperture formed in an article, which comprises: magnetically holding the headed end with the pin depending toward and aligned with the washer; releasing the magnetic force to drop the pin into the aperture; inverting the pin to seat the washer against the headed end; again inverting the assembled pin and washer; and again magnetically holding the head with the pin depending toward and aligned with the aperture in the article; supporting the washer in a position spaced from the headed end a distance greater than the distance between the depending end of the pin and the aperture; releasing the magnetic force to drop the pin through the supported washer to move the depending end into the aperture; and then releasing the washer to drop the pin into the aperture and move the washer into engagement with the article.

3. In a method of assembling a group of washers and a wafer with a like group of holes therethrough onto shanks of a group of headed leads: supporting the headed leads with the shanks thereof depending downwardly; positioning a group of washers in alignment with said shanks of said leads; releasing said headed leads to move depending ends of the shanks partially through said washers; inverting the leads and washers to move the washers along the shanks to engage the heads on the leads; repositioning the leads and washers to support the heads with the shanks depending downwardly while holding the washers in the vicinity of the heads; positioning said wafer below said leads with the holes therein aligned with the depending ends of the shanks; releasing the leads to move the heads into engagement with the washers while the ends of the shanks move through the aligned holes in the wafer; inverting the washers, leads, and wafer to move the wafer a predetermined distance along the group of the leads; reinverting the washers, leads, and wafer; and releasing the washers to drop the shanks through the wafer and move the washers into engagement with the wafer.

4. In a method of assembling each of a group of leads each having a headed end and an unheaded end, through a washer and then with an article having a group of apertures arranged in a predetermined pattern: supporting said group of leads in parallel relationship with each other and arranged in said predetermined pattern, with said headed ends oriented upwardly; positioning a group of washers arranged in said predetermined pattern below the unheaded ends of said leads with each of said washers aligned with one of said leads; releasing said leads to move the unheaded ends of said leads into said washers; inverting said leads and said washers to slide said washers along said leads and into engagement with said headed ends; reinverting said leads while holding the leads with said headed ends aligned in a plane; supporting the washers spaced a predetermined distance from the headed ends of the leads; placing said article below the unheaded ends of said leads a distance less than said predetermined distance while aligning said apertures with said leads; releasing said leads to move the headed ends of the leads through said predetermined distance into engagement with the washers and move the unheaded ends of the leads into the apertures in said article; and releasing said washers to move said washers and leads in unison relative to said article to thread said leads through said apertures and support said washers and said leads against said article.

5. A method of assembling a group of headed leads, a group of washers, and a pair of members having a pattern of apertures formed therethrough, each of said apertures being larger than the shank of a lead but smaller than the head of a lead; supporting a group of leads in a pattern corresponding to said pattern of apertures with the unheaded ends of the leads extending downwardly; positioning a group of washers in a pattern corresponding to the pattern of leads beneath and spaced from said leads; releasing the leads to partially drop through said washers; inverting the washers and leads to slide the washers against the headed ends of the leads; reinverting the leads; supporting the washers and the leads with the headed ends a predetermined distance from the washers; supporting a first member with the apertures aligned with the unheaded ends of the leads and at a distance which is less than said predetermined distance; releasing the leads to drop said unheaded ends into said apertures of said first member; supporting said washers and said headed ends to retain the leads partially extending through the apertures in said first member; supporting a second member with the apertures aligned with said partially extending leads; releasing said washers and leads to drop said leads through said apertures in the first member into the apertures in said second member where the leads are maintained in position by engagement of the washers with the top surface of said first member; and releasing said first member to advance into engagement with the second member and move said leads through said apertures.

6. In a method of assembling a plurality of predetermined groups of paramagnetic leads, each lead having a headed end and an unheaded end, with a plurality of groups of washers and a plurality of wafers each having a predetermined pattern of apertures: magnetically positioning and then supporting a plurality of groups of said leads in patterns, each of which corresponds to said predetermined pattern, in an initial position with the longitudinal axes of said leads parallel and the headed ends oriented upwardly; moving and then holding said leads to align the heads of said leads in a plane; placing a plurality of groups of washers, each arrayed in said predetermined pattern, below and aligned with the unheaded ends of said leads; releasing said leads to drop and move the lower unheaded ends of the leads through said washers; inverting said leads to slide the washers along said leads and into engagement with the headed ends thereof; magnetically holding said headed ends in a plane; reinverting said leads to the initial position to slide said washers along said leads; supporting said washers a predetermined distance out of engagement with said headed ends; aligning a plurality of wafers a distance less than said predetermined distance beneath the unheaded ends of said leads with the apertures in said wafers aligned with said unheaded ends of said leads; releasing said leads to drop said predetermined disTance to support said headed ends in engagement with said washers and to move said lower unheaded ends through said apertures in said wafers; inverting said leads and wafers to slide said wafers along said leads; holding said wafers spaced from the unheaded ends of the leads; and releasing said washers to drop said washers and said leads into engagement with said wafers.

7. A method of loading an array of paramagnetic pins in a fixture for subsequent processing, each of said pins having a headed end and an unheaded end, wherein the fixture comprises a first horizontal plate having a first array of holes therethrough and a second plate overlying the first plate and having a second, like array of holes therethrough, each of said holes in the second plate being smaller than the headed end of a pin, which comprises: moving one plate relative to the other to move the holes out of alignment; placing a mass of paramagnetic pins on the second plate; applying a magnetic field transversely of the plates to vertically suspend the pins with lower ends thereof bearing against the second plate; imparting relative movements between said plates and said suspended pins to move the unheaded ends of certain of said pins into the holes in the second plate; and moving one plate relative to the other to move the holes into alignment to permit those pins positioned in the holes in the second plate to pass through the holes in the first plate and be retained by the headed ends engaging the top surface of the second plate.

8. In an arrangement of apparatus for assembling a washer onto a shank of a pin having a headed end: a frame having a pair of spaced vertical end plates; a first plate having a slot for receiving the shank of the pin and supporting the headed end, said slot being narrower than the diameter of the headed end and the washer; means for slideably supporting said first plate between said end plates with the shank of the pin extending in a downward direction; means for lifting the pin in the slot and then releasing the pin; means for supporting a washer in the space vacated by the lifted pin and in position to receive the released pin; and a second plate slideably mounted between said end plates for retaining the pin in the slot upon inversion of the frame, said first plate having a bore extending therethrough at one end of said slot, said bore being larger than the washer and positioned by sliding the first plate to pass said washer along said shank into engagement with said headed end.

9. In an assembly fixture for assembling a plurality of groups of paramagnetic leads supported in parallel spaced relation, each of said leads having headed and unheaded ends, with a plurality of groups of washers and then with a plurality of wafers each having a predetermined pattern of apertures: a transfer member having a plurality of groups of bores formed therethrough for guiding said leads, each of said groups arranged in said predetermined pattern; means movably mounted for magnetically supporting a group of said leads in an initial position to align said headed ends in a plane with said unheaded ends depending downwardly into said groups of bores; a locking plate interposed between said supporting means and said transfer member and having a plurality of groups of keyhole-shaped openings formed therein and arranged in said predetermined pattern, with a circular portion of each of said openings aligned initially with one of the bores in said transfer member for receiving said groups of leads, said keyhole opening having a slotted portion which is narrower than the diameter of the headed end and the washer; means mounting said locking plate for sliding movement to position slotted portions of said keyhole openings over said bores in said transfer member and to confine said washers and said headed ends between said locking plate and said supporting means; means for holding said plurality of groups of washers below the unheaded ends of said leads with each of said groups of washers arranged in said predetermined pattern and with each of said washers aligned with one of said bores in said transfer member; a second locking plate, having a plurality of openings formed therein, said second locking plate interposed between said holding means and said transfer member for guiding said wafers into engagement with a bottom surface of said transfer member when said fixture is inverted, each of said openings in said plate having a slot extending radially therefrom, said slot being narrower than the diameter of a wafer; and means mounting said plate for sliding movement to lock said wafers against said transfer member and to permit one lead of each of said groups to be received in one slot before said fixture is returned to the initial position.

10. In a fixture for assembling a plurality of groups of paramagnetic leads, each of said leads having headed and unheaded ends, with a plurality of groups of washers, and then with a plurality of wafers, each having a predetermined pattern of apertures, said leads held initially in parallel, spaced relation with said headed ends oriented upwardly: a transfer member having a plurality of groups of bores formed therethrough, each of said groups having said bores arranged in said predetermined pattern; magnetic means for supporting said leads with said headed ends aligned in a plane and with said unheaded ends received in said bores in said transfer member; a first locking plate interposed between said magnetic means and said transfer member and having a plurality of groups of keyhole-shaped openings formed therein and arrayed in said predetermined pattern with a circular portion of said openings aligned with the bores in said transfer member, and with slotted portions of said openings being narrower than said washers and said unheaded ends; means mounting said first locking plate for sliding movement to position the slotted portions of said keyhole openings over said bores in said transfer member and to confine said washers and said headed ends between said locking plate and said magnetic means; means for holding said plurality of groups of wafers arranged in said predetermined patterns below the unheaded ends of said leads with each of said washers aligned with one of said leads; a second locking plate having a plurality of openings and interposed between said wafers and said transfer member for passing said wafers to slide along the unheaded ends of said leads and against the bottom surface of said transfer member when said fixture is inverted, each of said openings aligned initially with one of said groups of bores in said transfer member and having a slot formed therein radially extending therefrom, each of said slots being narrower than the wafer and larger than the diameter of the unheaded end of the lead; a retaining plate slideably mounted between said magnetic means and said first locking plate for engaging and holding the leads in the transfer member when said fixture is inverted; and means for slideably mounting said second locking plate to shift said second locking plate to lock said wafers against said transfer member and to permit one lead of each of said groups of leads to be received in one slot before said fixture is returned to said initial position.