US3722087A

US3722087A - Method and apparatus for mounting terminals on a circuit board

Info

Publication number: US3722087A
Application number: US00189683A
Authority: US
Inventors: Q Berg
Original assignee: Berg Electronics Inc
Current assignee: Berg Electronics Inc
Priority date: 1971-10-15
Filing date: 1971-10-15
Publication date: 1973-03-27
Anticipated expiration: 1990-03-27

Abstract

Loose piece eyelets are wiped back and forth across the top of a tilted transfer plate having eyelet receiving holes therein. An air flow is maintained through the holes in the transfer plate to seat the eyelets in the holes. A circuit board is positioned in a press on top of an anvil plate and the loaded transfer plate is mounted on top of the circuit board. Closing of the press moves a punch plate toward the transfer plate to force the eyelets from the transfer plate into holes in the circuit board and bring the lead ends of the eyelets into engagement with anvils on the anvil plate to stake the eyelets to the circuit board. Eyelets can be staked to the circuit board in holes off center with respect to the staking tooling.

Description

O 1 e Unite tates Patent 11 1 1 1 Berg 1 Mar. 27, 1973 54] METHOD AND APPARATUS FOR 2,833,091 5/1958 Whitney ..53 142 MOUNTING I AL ON A 2,858,597 11 1958 Kraeiner ..29/10 CIRCUIT BOARD 2,920,740 1/ 1960 Whitted ..198/33 3,085,314 4/1963 Leiching ..29/604 Inventor: Quentin g, New Cumberland, 3,129,494 4/1964 Perkins.... ....29/203 MM Pa. 3,548,369 12/1970 Garver ..29/625 X 3,574,935 4/1971 Ber ..29/203 B [73] Berg New 3,578,189 5 1971 Yon kers ..214/152 berland, Pa.

[22] Filed: Oct. 15, 1971 Primary Examiner-Thomas H. Eager 211 App]. No.: 189,683 At'omey*mmas Hmke [57] ABSTRACT 12?} ii'fi'if'.:3:JjiijijjiiiijjfYfffif???510111501 Leeee eieee eyeleee eee eeeee eeekeee feeeh [58] Field of Search ..29/626 203 B 203 v 625, a i h eyelet 29/604 203

MM

10, 142, mg holes therein. An arr flow 18 mamtamed through 198/31} 214/152; 227/153: 152; 249/96; the holes in the transfer plate to seat the eyelets in the 425/109 holes. A circuit board is positioned in a press on top of an anvil plate and the loaded transfer plate is mounted [56] References Cited on top of the circuit board. Closing of the press moves a punch plate toward the transfer plate to force the UNITED STATES PATENTS eyelets from the transfer plate into holes in the circuit 568 201 9/1896. Latham ..249/96 board and bring the lead ends of the eyelets into 572:340 12 1896 Estabrook ..425/109 gagemeht with ahvhs the anvil Plate Stake the 1,053,227 2 1913 Sandoz-Moritz ..53/112 eyelets t0 the Circuit board- Eyelets can be staked to 1,062,608 5/1913 Sandoz-Moritz ..53/235 the circuit board in holes off center with respect to the 1,649,540 11/1927 Moscini ..227/153 staking tooling. 2,181,573 11/1939 Bunker... ..29/211 D 2,583,615 l/l952 Tobey ..227/152 12 Claims, 16 Drawing Figures PATENIFUmzmm 3722,08?

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I 5 Quenhn B g BY Thomas Ookev;

d s ornelj METHOD AND APPARATUS FOR MOUNTIN TERMINALS ON A CIRCUIT B I The invention relates to an improved method and apparatus for rapidly and simultaneously staking a large number of eyelets or terminals to a circuit board in a given pattern. A stream of loose piece eyelets is flowed down the top of a tilted transfer plate having eyelet receiving bores formed therethrough in the pattern in which the eyelets are to be staked to the circuit board. An air flow is maintained through the bores to pull eyelets into the individual bores. Flexible wiping flaps lightly engage the top of the transfer plate and are moved up and down the plate to facilitate uniform spreading of the eyelets across the plate and displace eyelets which are held against the eyelet receiving bores in improper orientation. Another wiping flap is moved back and forth across the plate at a distance above the plate to break up clusters of eyelets held above the bores by the parasitic drag of air flow through the bores. The combination of flowing the eyelets down the plate together with the wiping assures rapid loading of eyelets into the bores. One thousand eyelet receiving bores in a transfer plate area measuring 12 inches by 14 inches may be loaded with 0.050 inch diameter eyelets in about seconds. Frequently there is a small number of bores, usually about three or four, which remain unfilled after loading. These bores may be easily hand loaded by the operator.

Following loading of the transfer plate the plate is moved to a staking press. The eyelet receiving circuit board is mounted on an anvil plate carrying a staking anvil beneath each eyelet receiving circuit board hole. The transfer plate is mounted above the circuit board and beneath a punch plate carrying punches arranged in the same pattern as the anvils and transfer plate bores. Closing of the press brings the punches into engagement with the eyelets so that the eyelets are forced from the bores and into the circuit board holes. When the press bottoms the lead ends of the eyelets engage the anvils and are flared outwardly to stake the eyelets to the circuit board.

The transfer plate bores and the staking tooling enable eyelets to be staked to circuit board holes which are laterally offset somewhat from the desired or nominal hole location. The bores and staking tooling are located on the nominal axes of the circuit board holes so that laterally offset of the circuit board holes for a given distance in any direction from nominal axis will not prevent staking of the eyelet to the board. This feature is important since in the manufacture of production quantities of circuit boards it is invariable that the circuit board holes will not be located exactly at the desired location.

Another advantage of the invention relates to the fact that the eyelets are positively driven into the circuit board holes during the staking operation. In circuit boards where the holes are formed by a punching operation fibrous strands frequently extend from the walls of the holes into the interior of the holes to prevent directly loading the eyelets into the circuit board hole in the same manner as the eyelets are loaded into the transfer plate; Staking as described drives the eyelet bodies past the fibrous strands to stake the eyelets in the holes.

The invention is an improvement over the disclosure of my previous US. Pat. No. 3,574,935 for apparatus and method for applying terminals to a circuit board. In

that patent terminals are severed from a carrier strip and then guided through individual drop tubes to desired locations on a transfer plate. The terminals are then lifted by a vacuum from the transfer plate to a ram plate where they are held by a parisitic drag until they are staked to a circuit board. With the present invention it is possible to stake more eyelets to a circuit board more rapidly than is possible in my prior apparatus. Modification of the invention to stake eyelets to circuit boards in a different pattern is more easily attained in the case of the present invention than in the prior disclosure.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings of which there are six sheets.

IN THE DRAWINGS FIG. 1 is a perspective view disclosing apparatus for mounting terminals on a circuit board;

FIG. 2 is a partially broken away side view of the transfer plate loader;

FIG. 3 is a view taken along line 3-3 of FIG. 2;

FIG. 4 is a partially broken away top view of the loader;

FIG. 5 is a partially broken away view taken along line 5-5 of FIG. 4 following mounting of a transfer plate and extension of the wiping brush;

FIG. 6 is a perspective view illustrating operation of the loader;

FIG. 7 is a sectional view taken along line 77 of FIG. 8 illustrating an eyelet as positioned in a hole in the transfer plate;

FIG. 8 is a top view of the terminal loaded in the transfer plate;

FIG. 9 is a partially broken away side view of the press used to stake the eyelets carried in the transfer plate to a circuit board;

FIGS. 10, 11, 12 and 13 are enlarged views illustrating the staking of one of the eyelets in the transfer plate;

FIGS. 14 and 15 illustrate staking of an eyelet in a circuit board hole which is axially offset from the staking tooling; and

FIG. 16 is a top view of a circuit board hole illustrating fibers extending therein.

DESCRIPTION OF THE APPARATUS The apparatus disclosed in FIG. 1 simultaneously attaches a large number of circuit board eyelets to a circuit board. The eyelets may be of the type disclosed in Olsson Pat. No. 3,504,328 which is assigned to Berg Electronics, Inc. of New Cumberland, Pennsylvania. Loading apparatus 10 is supplied with a mass of loose piece eyelets which are moved over the surface of a transfer plate 12 and are seated in bushings extending through the thickness of the transfer plate. Following loading of the transfer plate 12 the plate is removed from the loading apparatus. The circuit board 14 is mounted on an anvil plate 16 and the transfer plate is positioned above the circuit board with each eyelet holding bushing above an eyelet receiving hole through the thickness of the circuit board. A punch plate 18 is mounted above the transfer plate.

The transfer plate, circuit board and anvil plate as sembly is then moved between the pressure plates of press 20. The upper pressure plate carries a punch plate 18 with punches located in axial alignment with the eyelet carrying bushings on the transfer plate. Upon closing of the press the punches on plate 18 are lowered into the bushings of transfer plate 12 to push the eyelets confined therein into the aligned circuit board holes. The lead ends of the eyelets extend through the circuit board holes through the bottom of the circuit board and are flared outwardly by anvils on plate 16 to stake the eyelets to the circuit board.

Closing of the press forces the eyelets through the circuit board holes despite glass fibers or other obstructions in the holes. The staking tooling and the somewhat rounded eyelets cooperate to stake eyelets into circuit board holes which are laterally offset from the nominal locations.

The loading apparatus will now be described in further detail. Apparatus 10 includes a base 22 having a working platform 24 on one side thereof and an eyelet loading box 26 on the other side thereof. The box 26 is tilted toward the front of the apparatus 10 and is mounted on support 28 extending above base 22. The loading box includes a cover 30 secured to support 28 by means of hinges 32 on the back of the support to facilitate opening of the loading box. A hood 34 is attached to cover 32 by slides 36 so that loading chamber 38 located beneath the hood may be opened by sliding the hood up under the cover. Strap 40 is attached to the cover to limit rotation of the cover about hinge 32.

The eyelets 42 loaded by apparatus 10 include a generally cylindrical body 44 having a flat multi tab flange 46 at one end thereof and a rounded or bulletnosed lead-in 48 at the other end thereof.

The transfer plate 12 is provided with a number of eyelet receiving bushings 50 extending through the thickness of the plate and arranged in the same pattern as the nominal pattern of the eyelet receiving holes in circuit board 14. Each bushing 50 is fitted in a bore 52 extending through plate 12 with flange 54 seated against shoulder 56. The cylindrical hole 58 extending through the bushing 50 has a radius slightly less than the maximum radius of the eyelet flange 46. A bevel lead-in 60 is provided at the top of holes 58 to facilitate seating of the eyelets 42 therein. As illustrated in FIGS. 7 and 8, when an eyelet is seated within a bushing 50 the outer edges of the flange 46 engage the bottom of the bevel 60 immediately adjacent hole 58 and the eyelet body 14 is positioned within the hole 58.

Transfer plate 12, as indicated in FIG. 1, is generally rectangular having a number of bushings 50 arranged in the desired pattern in the center thereof and with a pair of locating holes 62 on opposite edges thereof located outwardly of the bushings. When the hood 34 is raised beneath cover 30, the transfer plate may be positioned on edges 64 defining the periphery of a rectangular opening 66 in the bottom of the loading chamber 38. The opening 66 communicates the loading chamber 38 with a vacuum chamber 68 immediately beneath the loading chamber. A pair of locking air cylinders 70 are mounted on the opposite side walls of chamber 68 adjacent opening 66 with pins 72 carried by the free ends of the air cylinder piston rods extending through the opening 66. The plate 12 is positioned over the opening 66 with pins 72 extending into holes 62 following which the air cylinders are extended to move the rounded edge 74 of the transfer plate against the undercut edge 76 of the plate 78 which extends upwardly from the loading chamber and forms the bottom of eyelet entrance chamber 80. An eyelet feed tube 82 extends from blower 84 past an eyelet terminal collecting pipe 86 communicating with the bottom of the loading chamber 38 and past the loading chamber to a spout 88 extending into the top of chamber 80. A gravity trap 90 is provided in pipe 82 between the blower and the junction with collecting pipe 86.

When the blower 84 is actuated, a blast of air is forced through pipe 82 and into the chamber 80. The air blast carries loose piece eyelets 42 along with it so that the eyelets are flowed along the bottom of chamber 80 and across the transfer plate on the bottom of loading chamber 38. Eyelets collected in trough 92 .at the bottom of the loading chamber fall down the collecting tube to trap'90 where they are again blown up pipe 82 to chamber 80.

A pair of

eyelet spreading baffles

94 and 96 extend into chamber 80 from the top wall thereof. Baffle 94 extends laterally slightly beyond the mouth of spout 88 and is bent away from the spout at an angle so that the eyelets which are blown out of the spout are spread laterally of the spout and are deflected toward the plate 28. Second baffle 96 is located downstream of baffle 94 and extends laterally nearly the entire width of chamber 80. The baffle is more nearly perpendicular to plate 78 than baffle 94 and extends nearer to plate 78. Baffle 96 serves to further spread the eyelets blown from spout 88 and also to deflect the same down against plate 78. The combination of the two baffles assures that the eyelets blown from the spout 88 are spread uniformly across the width of the chamber so that a uniform supply of eyelets is flowed across the transfer plate.

Chambers

38 and 80 are the same width.

Sweeping air cylinder 98 is mounted on top of the cavity 80 with the piston rod 100 thereof extendable into the loading chamber 38. A brush assembly 102 is secured to the front end of rod 100 and includes a pair of primary eyelet sweepers 104 and a secondary sweeper 106. Each primary sweeper includes a flat flexible flap 108 carried by a support 110 secured to rod 100. Flaps 108 extend across all of the bushings in the transfer plate. The brushes 108 may be formed from a plastic or other suitable material. The secondary sweeper 106 is spaced a distance upstream or nearer spout 88 than the primary sweepers and includes a like flap 1 12 formed of a sheet of flexible material held by a support which is connected to the primary brushes by bolts 116.

Primary sweeper flaps 108 lightly engage

plates

12 and 78 so that as the brush assembly is moved back and forth, the brushes are wiped along the surface of the plates. The primary flaps 108 sweep a mass of eyelets back and forth over the bushings 50. The secondary brush sweeper 112 is spaced a slight distance above

plates

12 and 78 so that it does not engage the plates as the assembly 102 is moved back and forth. The secondary brush breaks up clusters of eyelets which may collect over bushings in plate 12.

A high capacity vacuum pump or other vacuum source (not shown) is connected to vacuum chamber 68 through relatively large diameter vacuum pipe 118 and opening 120 provided in the bottom of the chamber. A vacuum baffle plate 122 is spaced slightly from opening 120 in order to distribute the vacuum relatively uniformly throughout chamber 68. The baffle is required in view of the relatively high flow of air through the bushings in plate 12 into chamber 68 and through the vacuum pipe 118 to the vacuum source. A pair of fluorescent lights 124 is located on opposite sides of the vacuum chamber 68 beneath plate 12.

A control rod 126 extends from plate 128 of sweeping assembly 102 back along air cylinder 98. Two control microswitches 130 and 132 are mounted adjacent the ends of the air cylinder so that upon extension and retraction of the air cylinder, the end of the rod 126 is moved past. the triggers of the microswitch so as to open and close the switches. Mesh windows 134, illustrated in FIG. 4, are provided in the top of cavity 80 to permit visual inspection of the chamber.

Press illustrated in FIGS. 1 and 9 includes a base 140 having a lower pressure plate 142 mounted on the top thereof. Four posts 144 extend through holes in plate 142 and are attached to upper pressure plate 146. The lower ends of the posts are secured to a press mechanism (not illustrated) located within the base 140 which when actuated moves the upper pressure plate 146 toward and away from the lower pressure plate 142.

A tray 148 is movable from a position to one side of the

pressure plates

142 and 146 as illustrated in FIG. 1 to a position between the pressure plates. When the tray is inserted between the pressure plates it rests upon the lower pressure plate 142. A pair of locating pins 150 extend from opposite sides of tray 148 to facilitate the mounting of the transfer plate 12 thereon.

Punch plate 18 is provided with a number of eyelet punches 152 which extend outwardly of the bottom surface of the plate and are arranged in the same pattern as the pattern of the bushings 50 in transfer plate 12. While the punches 152 are illustrated in FIGS. 10 thru 15 as being integral with plate 18, obviously the punches may be separate inserts mounted within holes in the plate.

Each punch 152 includes a cylindrical body 154 having a reduced diameter cylindrical tip 156 at the end facing away from plate 18. The body and tip of each punch 152 are located on the same axis as that of the adjacent bushing 50. As indicated in FIG. 13, the diameter of punch body 154 is somewhat less than the diameter of the hole 58 in the bushing to facilitate driving of the eyelet through the bushing during the staking operation. The clearance between the punch and the bore in the bushing also facilitates retention of the eyelet flush upon shoulder 158 of the punch adjacent tip 152 during staking.

Anvil plate 16 is provided with a pair of locating holes 160 on opposite edges thereof so that it can be mounted on tray pins 150. A number of staking anvil inserts 162 are mounted in the anvil plate in the same pattern as the staking punches and bushings. Each anvil insert includes an obtuse conical staking tip 164 which is coaxial with associated bushing and punch. The included angle on opposite diametrical sides of the staking tip is about 130. It is desirable to provide a staking tip having an obtuse angle between opposite sides to assure that the eyelets are properly staked in off-center circuit board holes.

Circuit board 14 is mounted on pins 166 carried by anvil plate 16 so that the circuit board is properly oriented with respect to the staking tooling. Resilient pads 167 normally hold the board a slight distance above plate 16. During staking the circuit board is sandwiched between the transfer plate and anvil plate to collapse the pads 167 and move the circuit board toward the anvil plate. Metal spacers 168 on the anvil plate are provided to prevent the circuit board from resting flush upon the top of the anvil plate.

Suitable controls including microswitches, solenoid controlled valves and like mechanisms are provided to control the operation of

apparatuses

10 and 20. Some controls are illustrated in the drawings. The operation of air cylinder 98 in sweeping the brush assembly back and forth over the transfer plate-is preferably controlled by an automatic timer set for the required number of sweeps.

OPERATION OF THE APPARATUS Prior to the operation of loading apparatus 10, an adequate supply of loose part eyelets 42 is placed in the gravity trough 92 so that they will fall into the trap 90. At the start of the cycle of operation, hood 34 is pushed into cover 30 and an empty transfer plate 12 is positioned over opening 66 with pins 72 extending through locating holes 62 in the plate. Air cylinders are then extended in order to force the rounded edge 74 of the plate against the undercut edge 76 of plate 78. With the transfer plate held in this manner there is a smooth fit with plate 78 so that the eyelets are not worn as they move from plate 78 down the transfer plate. The other three edges of the transfer plate are seated flush upon edges 64 on the remaining three sides of opening 66. Eyelets which fall off the lower edge of the transfer plate are collected in trough 92, and fall back down tube 86.

With the transfer plate in the loading position the hood is lowered to the closed position and the vacuum source is actuated. The vacuum source provides a pressure differential between the loading chamber 38 and vacuum chamber 68. Because initially the bushings are free of eyelets there is a relatively large air flow through the holes in the bushings thus requiring a large volume vacuum source to maintain the desired pressure dif ferential of approximately one inch of water.

Actuation of the blower 84 causes a stream of air to move through eyelet feed tube 82 so that the eyelets are picked up from trap 90, moved through the tube and sprayed out of spout 88 in a stream against

baffles

94 and 96. The baffles serve to spread the stream of eyelets relatively uniformly across the width of chamber in the manner previously described. After a' supply of eyelets has accumulated behind the wiping flaps of brush assembly 102, air cylinder 98 is actuated to extend and retract piston rod thereby moving the primary sweepers 104 back and forth across all of the bushings in the transfer plate. The secondary sweeper is also moved back and forth across all but the bottom-most portion of the plate.

Movement of the sweepers permits the loose eyelets to tumble down from plate 78 and across the upper face of the transfer plate. The air flow through the bushings pulls individual eyelets into holes 58 to seat the same therein as illustrated in FIG. 7. Upward movement of the brush assembly upon retraction of air cylinder 98 moves the primary sweepers back up the surface of the transfer plate to dislodge eyelets which are held against bushings in improper alignment. Thus the flow of air through a bushing could hold an eyelet against the bevel 60 with the body of the eyelet projecting above the top of the transfer plate. This misoriented eyelet would be swept away by the primary sweepers thus freeing the bushing for reception of a properly oriented eyelet.

Because of the high air flow through the bushings, there is a tendency for a number of eyelets to be held in a cluster against a single bushing. Such a cluster 180 is illustrated in FIG. 5. Movement of the secondary sweeper 106 across the transfer plate breaks up clusters 180 to provide additional free eyelets so that they may be drawn into the bushings.

During loading of the transfer plate, air cylinder 98 is cycled to extend and retract a number of times sufficient to load substantially all of the bushings with eyelets. In the case of a transfer plate with 1,000 bushings, a pressure differential across the plate of one water inch or slightly more and a forward and back sweeping cycle of one second duration, it has been found that approximately 65 to 70 percent of the bushings are filled during the first sweep. Ten sweeps substantially fills all of the bushings with the possibility that perhaps one to five of the bushings remains unfilled. Considering that the eyelets are 0.050 inches in diameter, the efficiency of the loading apparatus is immediately apparent. At least 99.5 percent of the bushings can be filled reliably within a cycle time of 10 seconds.

As the bushings become filled during cycling of the air cylinder, the air flow through the transfer plate is reduced thereby increasing the pressure differential across the plate. In order to prevent this increased pressure from pulling the eyelets completely through the bushings, a pressure limiting valve 182 may be provided in one wall of the vacuum chamber 68. The valve opens automatically when the pressure differential across the transfer plate increases to about ten water inches. A further increase in pressure would increase the parisitic drag on the eyelets so as to bend the flange tabs sufficiently to permit the eyelets to be drawn through the bushings.

During movement of the brush assembly 102 back and forth across the transfer plate, blower 84 continuously replenishes the supply of eyelets behind the flaps thereby assuring that there is a supply of eyelets on the transfer plate available to be pulled into the bushings by the air flow into the vacuum chamber. After the air cylinder 98 is cycled sufficiently to fill substantially all of the bushings with eyelets, it is retracted to the position of FIG. 2 with the brush assembly 102 withdrawn into chamber 80 free of the transfer plate. The operator then reactivitates the blower 84 and vacuum source and raises hood 34 into cover 30 and inspects the transfer plate. A brush may be used to sweep the top of the plate to remove any eyelets not properly seated in bushings. After the plate has been swept clean, the operator is able visually to discern whether or not there are any unfilled bushings from the light passing through the bushings from bulbs 124. Such bushings may be easily filled by the use of a hand loader. As mentioned previously, the number of sweeps of the brush assembly back and forth across the transfer plate is determined so that during the loading operation all but a very few of the bushings are loaded with eyelets. Since the loading is accomplished on a random basis, it is not possible to assure total loading.

After the operator has hand filled the unfilled bushings air cylinders are retracted to move the transfer plate free of plate 78 and permit the operator to remove the loaded transfer plate from loading apparatus 10. After loading of the transfer plate the eyelets held therein are next staked to the circuit board 14. In the rest position the upper and

lower pressure plates

142 and 146 of the press 20 are spaced apart and punch plate 18 is mounted on the upper press plate 146 by a pair of pins 170. Tray 148 is withdrawn from between the pressure plates as indicated in FIG. 1. Anvil plate 16 is mounted on pins 150 extending from the bottom of the tray. Circuit board 14 is placed on the anvil plate on locating pins 166 so that a circuit board hole 184 is positioned above each anvil insert 162. The circuit board is held above spacers 168 by resilient cushions 167. The loaded transfer plate 12 is then loaded on top of the circuit board on spring backed pins 169 which extend from the anvil plate. With the transfer plate mounted on pins 169 each bushing 50 is located in axial alignment with the nominal location of a circuit board hole 184 and the associated anvil insert 162. The spring backed pins 169 hold the transfer plate slightly above the circuit board.

After the circuit board and loaded transfer plate have been mounted on the anvil plate, the tray 148 is moved between the open press plates so that each anvil insert, circuit board hole and bushing are in alignment with a punch 152. After the tray has been moved between the pressure plates to the proper position, the operator actuates the press to lower upper press plate 146 thereby moving the punch plate down toward the transfer plate. Descent of the upper press plate stakes the eyelets carried by the transfer plate in the circuit board holes as illustrated in FIGS. 10 thru 13. All of the eyelets are staked to the circuit board in the same manner.

As indicated in FIG. 10, lowering of the punch plate 18 brings punch 152 toward the associated bushing 50 so that the tip 156 of the punch extends into the hollow top of the eyelet. Further lowering of the punch plate seats the shoulder 158 against the inner portion of the eyelet flange 46 and drives the eyelet down bore 58 past the bevel 60. The tips of the flange which engage the bevel are bent around the shoulder 158 into the clearance between bore 58 and punch body 154 to assure that the eyelet is held snugly against the punch during the staking'operation. The snug fit between the eyelet and punch prevents tilting of the eyelet body during the punching operation. As illustrated in FIG.

10, the eyelet body is held against the punch so that it does not touch the sides of the bore as it is moved toward the circuit board.

As plate 146 is lowered the transfer plate is forced down and compresses pins 169 so that it rests flush upon the upper surface of circuit board 14 as indicated. Lowering of the punch plate moves eyelets through the bores 58 to position the eyelet bodies 44 within the circuit board holes 184. The lead end 68 provided by the bullet nose or rounded lower end of the eyelet body facilitates movement of the cylindrical eyelet body into the circuit board hole. This feature is particularly important in the case where the circuit board holes 184 are axially offset with respect to the tooling axes as will be described in connection with FIGS. 14 and 15.

The punch plate 18 engages the upper surface of transfer plate 12 at the time the punches have seated the top flange of the eyelet against the top surface of the circuit board. This position is illustrated in FIG. 11. The eyelet bodies extend through the circuit board hole with the lower lead-in end projecting outwardly of the circuit board past printed circuitry 186. Further lowering of the upper press plate 146 moves the ram plate, transfer plate and circuit board toward the fixed anvil plate thereby compressing the cushions 167 and bringing the exposed end of the eyelets into engagement with the conical staking tips so that the eyelet ends are flared outwardly to stake the eyelets to the circuit board. Movement of the circuit board toward the anvil plate is limited by spacers 168.

When the upper press plate has lowered sufficiently to bring the tooling into the staking position of FIGS. 12 and 13, the press raises to return the upper press plate to the open position of FIG. 1. Tray 148 may then be removed from between the press plates and the transfer plate and the circuit board with the eyelets staked thereto may be lifted from the anvil plate. Removal of the circuit board from the press completes the cycle of operation.

In production operation, the operator uses a pair of like transfer plates 16 with loading apparatus and press 20. The first transfer plate is loaded with eyelets and then mounted on the anvil plate with a circuit board therebetween so that it may be positioned between the press plates for staking. During the staking operation the operator mounts the second transfer plate in the loading apparatus and initiates the loading cycle. After staking has been completed and the press plates are again separated, the operator removes the transfer plate and staked circuit board from the anvil plate and repositions a new circuit board on the anvil plate. The newly loaded transfer plate is then inspected to make sure that all of the bushings are loaded and if necessary the empty bushings are hand loaded. This transfer plate is positioned on top of the circuit board and the tray is then positioned between the open press plates and the staking cycle is initiated. The transfer plate which has been removed from the press is then positioned in the loading apparatus 10 and the loading cycle is started.

Through the use of two staking plates it is possible to load one of the transfer plates with eyelets at the same time as eyelets are staked on a circuit board from the other transfer plate. In this manner, it is possible to stake eyelets to a larger number of circuit boards than in a conventional loading and staking apparatus.

Another advantage of the invention is that during staking the eyelets are positively seated in the circuit board holes by the punches. In a number of instances the circuit board holes are formed in a fibrous board by a punching operation which leaves fiber strands extending into the interior holes from the side walls. FIG.

16 illustrates a circuit board 190 having a hole 192 formed therethrough with a number of fiber strands 188 extending into the interior thereof. These fiber strands make it impossible to draw eyelets 42 directly into the circuit board holes by a flow of air through the holes. The fibers are sufficiently strong to prevent the eyelet from seating in the hole.

The problem is overcome by loading eyelets in a transfer plate and then positively driving them into the circuit board holes by means of punches. The punch driven eyelets bend the strands out of the insertion path. Additionally, because the diameter of the insert bores is somewhat larger than the diameter of the circuit board holes, it is possible to load the transfer plate somewhat more rapidly than direct loading of the eyelets in the circuit board holes. The use of masking templates for covering openings in the circuit board during the loading operation, a reinforcing plate to prevent buckling of the circuit board and other devices required for loading the eyelets directly on the circuit board, are eliminated by the use of the transfer plate.

The rounded bullet nosed lead-in 48 at. the end of the eyelet is provided to facilitate movement of the eyelet body into the circuit board hole during the staking. When the circuit board hole is properly aligned with the axis of the staking tooling, as illustrated in FIGS. 10 thru 14, the hole is located directly beneath the eyelet body so that upon movement of the eyelet toward the circuit board hole, the body is lowered directly into the hole.

However, in some circuit boards, the eyelet hole is not exactly located so that the hole axis 194 is offset somewhat from the tooling axis 196. This situation is illustrated in FIGS. 14 and 15. Lowering of the punch in this situation moves the eyelet body toward the offset hole so that the rounded lead-in 48 engages the hole edge 198 located nearest tooling axis 196. So long as edge 198 engages the lead-in and the hole 200 is located within the larger diameter bushing hole 58, the lead-in will guide the eyelet body into the hole and further lowering of the punch will seat the major portion of the eyelet flange 46 on the top of the circuit board.

When the eyelet is seated in the hole, the lead-in projects out of the hole on the bottom of the circuit board. As the upper press plate bottoms the circuit board is moved down to force the offset lead-in against the anvil insert so that a major portion of the insert is flared outwardly of the hole to stake the eyelet to the circuit board. Staking of an eyelet in an offset circuit board hole is illustrated in FIG. 15. Staking is achieved despite the offset because the included angle of the conical staking tip 164 is relatively shallow. As mentioned previously, it is desirable that this angle be approximately During staking of the eyelets in offset circuit board holes the punch tip 156 assures that at least part of the eyelet flange is held against the tip of the circuit board at the edge of the hole. See FIG. 15.

While I have illustrated and described a preferred embodiment of my invention, it is understood that this is capable of modification, and I therefore do not wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations as fall within the purview of the following claims.

What I claim as my invention is:

1. Apparatus for loading terminals into bores formed in a flat plate comprising a transfer plate having terminal receiving bores formed through the thickness thereof and arranged in a desired pattern; a tilted plate support engagable with the plate away from the bores; a loading chamber above the support and a vacuum chamber beneath the support; a vacuum source communicating with the vacuum chamber to maintain the pressure in the vacuum chamber beneath that in the loading chamber; a terminal transportation system including an entrance chamber communicating with the loading chamber at the top of the support and having a lower floor forming an extension of the plate when mounted on the support, a loose piece terminal trap, a terminal supply conduit extending from said trap to a mouth opening into the entrance chamber, a terminal return conduit joining the loading chamber at the bottom of the support to the trap, air pressure means for directing a flow of air past said trap and through said supply conduit to pick up a number of loose piece terminals and direct a stream of terminals through the mouth and into the entrance chamber, and baffle means in the entrance chamber for spreading the stream of terminals across the width of the plate; and a sweeping assembly including a sweeper engagable with the plate for dislodging misaligned terminals from the bores in the plate, a cluster breaker, and means for moving said sweeper and cluster breaker back and forth across the plate.

2. Apparatus as in claim 1 wherein said sweeper comprises a pair of closely spaced flexible flaps having edges engaging the plate, and wherein said cluster breaker comprises a third flexible flap located a distance nearer the mouth than the sweeper.

3. Apparatus as in claim 1 including means for limiting the pressure differential across the board as terminals are loaded into the bores.

4. Apparatus for mounting terminals on a circuit board in a given pattern comprising a loading chamber; a vacuum chamber communicating with said loading chamber; a transfer plate having terminal receiving bores therein arranged in said pattern; a plate support for locating the transfer plate in the opening between the chambers; vacuum means for lowering the pressure in the vacuum chamber below that of the loading pressure whereby terminals are drawn into the bores; transport means for flowing a stream of loose piece terminals through the loading chamber and across the transfer plate; a flat flexible wiping flap in the loading chamber with one edge thereof engaging the transfer plate; means for moving the flap back and forth across the transfer plate to dislodge misaligned terminals from bores in the plate; and press means for forcing terminals from the transfer plate bores into holes in a circuit board.

5. Apparatus as in claim 4 including a cluster breaker movable with said flap and spaced a distance above the transfer plate for breaking up clusters of terminals formed thereon.

6. Apparatus as in claim 3 including means for limiting the pressure differential across the transfer plate as terminals are loaded into the bores therein.

7. Apparatus as in claim 4 wherein said transport means includes a closec conduit having a terminal receiving opening in the loading chamber to one side of the plate support, a terminal receiving trap, a terminal emitting opening at another side of the transfer plate support and means for flowing a stream of terminals from said opening in a direction toward the transfer plate.

8. Tooling for simultaneously staking a plurality of terminals to a circuit board in a given pattern comprising a terminal loading terminal plate having a number of cylindrical bores formed through the thickness thereof and oriented in said pattern, each bore having an increased diameter lead-in on one side of the terminal plate to permit an eyelet type terminal to be confined in the bore within the thickness of the terminal plate with the cylindrical body of the terminal in the bore and the terminal flange extending beyond the bore and engaging the sides of the lead-in below the surface of the terminal plate; a punch plate on the lead-in side of the terminal plate including a plurality of punches, each punch having a cylindrical body axially aligned with a bore in the terminal plate and having a diameter slightly less than the interior diameter of the bore, a reduced diameter nose at the free end of the punch and a locating shoulder surrounding the nose; and a staking plate on the opposite side of the terminal plate including a plurality of conical staking anvils, each staking anvil being axially aligned with a bore whereby upon positioning of a circuit board between the terminal plate and the staking plate with a circuit board hole in nominal alignment with the axis of each bore relative movement of the punch plate toward the anvil plate moves the punches into engagement with the terminals, and forces the same through the bores while seated on the locating shoulders, positions the bodies of the terminals within circuit board holes with the major portion of each flange seated against the top of the circuit board and stakes a major portion of the free end of the eyelet body adjacent the bottom of the circuit board.

9. A method of mounting terminals on a circuit board comprising the steps of flowing a stream of loose piece terminals down a tilted transfer plate while maintaining a pressure differential across the plate to draw properly oriented individual terminals into bores in the transfer plate, dislodging misaligned terminals held against bores as a result of the pressure differential, and breaking up clusters of terminals held against bores to load nearly all of the bores with terminals; manually inserting properly oriented terminals into the remaining unloaded bores to completely load the transfer plate; positioning the transfer plate in a press adjacent a circuit board with circuit board holes in alignment with the bores; and closing the press to force the terminals from the transfer plate into the circuit board holes.

10. The method of mounting individual loose piece terminals in holes in a circuit board having a given pattern comprising the steps of moving a mass of loose piece terminals over a transfer plate having bores therein arranged in said pattern while maintaining a pressure differential across the transfer plate to seat individual terminals in proper orientation in substantially all of the bores; inserting terminals manually into the remaining unfilled bores; positioning the filled transfer plate against the circuit board with each bore in alignment with a circuit board hole; and moving the terminals from the transfer plate and into the holes in the circuit board.

in the plate, moving a sweeper lightly engaging the plate back and forth across the plate to dislodge misaligned terminals held against bores as a result of the pressure differential, and moving a sweeper spaced from the plate back and forth across the plate to break up clusters of terminals held against the bores to load terminals into the bores.

Claims

11. The method of claim 10 including the steps of dislodging misoriented terminals from the transfer plate bores and the breaking up of clusters of terminals on the transfer plate.

12. The method of mounting terminals on a plate comprising the steps of flowing a stream of loose piece terminals across the top surface of a tilted plate while maintaining a pressure differential across the plate to draw properly oriented individual terminals into bores in the plate, moving a sweeper lightly engaging the plate back and forth across the plate to dislodge misaligned terminals held against bores as a result of the pressure differential, and moving a sweeper spaced from the plate back and forth across the plate to break up clusters of terminals held against the bores to load terminals into the bores.