US3123703A

US3123703A - R loeper

Info

Publication number: US3123703A
Authority: US
Publication date: 1964-03-03
Anticipated expiration: 1981-03-03

Description

March -3, 1964 R. P. LOEPER 3,123,703

METHOD AND APPARATUS FOR ATTACHING ARTICLES To A STRIP Filed Nov. 24, 1961 6 Sheets-Sheet l EVE/V773,? 5 LIUEPE'FP 21/ if W 7- TEJFNE'H March 3, 1964 R. P. LOEPER 3,123,703

METHOD AND APPARATUS FOR ATTACHING ARTICLES TO A STRIP Filed Nov. 24, 1961 6 Sheets-Sheet 2 J/:/ VE'N 757/ H R Fl LUE'PE' R. P. LOEPER March 3, 1964 6 Sheets-Sheet 3 Filed Nov. 24, 1961 O 9 a 1/ m I 1% u 0.7.. k %V H L." H n 7 m 3 E HI 5 H a l e m M a W m l LVE'NTUIF 9 QJQLIUEF EF T /F H R. P. LOEPER 3,123,703 METHOD AND APPARATUS FOR ATTACHING ARTICLES TO A STRIP March 3, 1964 6 Sheets-Sheet 4 Filed Nov; 24, 1961 J/I/VE'NTURY a F LUEPE j T -V E/ R. P. LOEPER March 3, 1964 METHOD AND APPARATUS FOR ATTACHING ARTICLES TO A STRIP 6 Sheets-Sheet 5 Filed Nov.. 24, 1961 JIIIVE'NTUIP F! LJUEQE'R'I' 35 March 3, 1964 R. P. LOEPER 3,123,703

METHOD AND APPARATUS FOR ATTACHING ARTICLES TO A STRIP Filed Nov. 24, 1961 6 Sheets-Sheet 6 iiq United States Patent Oil lice 3,123,703 Patented Mar. 3, 1964 York Filed Nov. 24, 1961, Ser. No. 154,733 6 Claims. (Cl. 219-103) This invention relates to work feeding apparatus and especially one designed to temporarily attach piece parts to a flexible strip to facilitate their processing.

The header used in the manufacture of certain transistors comprises a small metallic cup-shaped member wherein the outer surface of the closed end serves as a platform on which the semiconductor wafer is mounted. Customarily, the emitter, base, and collector leads, sealed in the interior of the header by glass, extend through openings in the platform. The open end of the header includes a flange. When assemblage of the header is completed, a can having a flange is placed over the header so that the flanges meet and are welded together. Following the glassing operation, it is required that the header be gold-plated prior to bonding the semiconductor wafer thereto to assure a high standard of electrical performance and reliability. Prior art techniques utilize a batch-type method of plating, employing plating barrels. Such a procedure does not lend itself to automation wherein it is desirable that articles pass in succession through various work stations. Further, the batch method often results in the entangling of the header leads and the use of excess amounts of gold. Rack plating methods are conducive to greater control, but again have the drawback of incompatibility with modern automation techniques for high-scale, efficient mass production. As described in a co-pending application, John L. Chapman, Jr., and Robert P. Loeper, Serial No. 154,744, filed November 24, 1961, a solution of the problem is attained in a continuous plating process by the use of a flexible steel tape to which the headers are attached to facilitate their transport through various plating baths and other work locations at different angular positions, the tape providing a direct electrical path to the headers as needed, at least in certain of the tanks used in the apparatus. This concept of header feeding by means of a flexible metallic tape necessitated the provision of a rugged reliable apparatus for the attachment of the headers to the tape.

Accordingly, it is an object of the invention to provide apparatus for attaching piece parts to a flexible strip of conducting material.

Another object is the attachment of transistor headers to a flexible tape which may be flexed to different angular positions in accordance with the desired position of the header at various operating stages and which concomitantly provides a positive electrical path to the header.

Another object of the invention is to provide apparatus for attaching transistor headers to a flexible steel tape, preferably by welding, and winding the attached headers onto a reel which later becomes the input for one or more processing operations.

In carrying out the invention, apparatus is provided for feeding articles and a tape in predetermined relative positions, perforating feed holes in the tape, and attaching the articles to the tape.

More specifically, the present invention embodies apparatus comprising a series of holders mounted on an endless carrier for feeding the headers, a tape feeding means, a perforating means for perforating feeding holes in the tape, and welding means for attaching the headers to the tape.

A feature of the invention resides in bending header leads attached to the tape alternately in opposite directions to assure adequate spacing between adjacent headers during later processing of the headers.

Other features and advantages will become self-evident as the invention is further described.

The invention may be more readily comprehended from a consideration of the following description read with reference to the drawings, wherein:

FIG. 1 comprises a plan View of the header attaching apparatus;

PEG. 2 is a partial end view of the apparatus;

FIG. 3 is a view, partially in section, of a holder for the transistor headers;

PEG. 4 is a view, partially in section, of the tape perforating apparatus;

FIG. 5 is a partial perspective enlarged view, schematically illustrating the mechanism for driving the punch;

FIG. 6 is a partial perspective enlarged view, schematically illustrating the welding station;

FIG. 7 is a detailed view, partially in section, of the welding station;

FIG. 8 is a partial plan view of the apparatus showing the feeding of the steel tape with the headers attached;

FIG. 9 is a view of a bending device for bending the successive headers away from the tape alternately in opposite directions;

FIG. 10 shows the insertion of plastic tape between successive windings of the steel tape to protect adjacent layers of transistor headers from each other, and

FIG. 11 is a partial detailed view in section of the wound steel tape carrying the headers and the plastic tape.

In PEG. 1, suitably mounted on frame 9 is shown a supply reel It) for the steel tape 11, which is fed through the apparatus in a manner which will later be explained. The operator, at loading station 12, inserts the transistor headers 13 in blocks 14 mounted on the endless chain 16, there being a pair of sprockets 17 engaging the chain at each side of the endless path. The chain is in two sections, as shown in FIG. 3, the blocks 14 being mounted between the two sections. It will be seen that the headers 13 are loaded so that the flanges 15 rest on the upper surface 18 of the blocks 14 while the three leads 19 of the header extend downwardly. The operator places the headers in the same position in each slot 20 of the blocks. More specifically, the header is located so that the same lead, for instance the base lead B (FIG. 3), is centrally located in slot 20 in a position facing the operator. Between the pair of sprocket wheels 17 at the loading position is a circular magnetic member 21 mounted on the shaft 22. The magnetic attraction provided by the member 21 retains the headers in the blocks until they reach the retaining strips 23 mounted alongside the endless chain, as shown in FIGS. 3 and 6.

The tape proceeds arounds the guide roller 24 in a path adjacent the lower end of the leads 19 of the headers. The tape and the headers are first fed to perforating station 26. Driving power for the perforating and welding mechanisms is provided from the main drive 27 coupled to the motor 28 and gear reducer 30. A clutch 29 is pro vided under the control of solenoid 31 for starting and stopping the apparatus. By a suitable driving arrangement, the vertically extending shaft 32, FIG. 5, carrying near its lower end a pair of

earns

33 and 34, is rotated. It will be noted that the shaft 32 actually penetrates through the horizontally extending shaft 36. The cams work respectively against a pair of

circular portions

37 and 38 on shaft 36, causing a back-and-forth motion of punch head 39. The punch head includes a pilot pin 41 which is longer than the punching member 42 and enters the previously punched hole 43 of the tape to assure that the tape is held in proper position when the punch member 42 punches the next succeeding hole. The small bits of punched-out steel move through opening 35. The holes 43 comprise, in essence, sprocket holes to facilitate driving and locating of the tape, not only in the present apparatus, but also in other apparatus to which the tape may later be fed. Coiled spring 40 (FIG. 5) imparts a slight counterclockwise bias to pin 45, while flat spring 40A tends to push the pin to the left. When the pilot pin 41 comes forward, it pushes pin 45 out of the feed hole 43 and the pivotal spring action moves the front end of pin 45 onto the tape alongside the feed hole to prevent blocking of the tape feed. When the tape is advanced, the next feed hole 43 is sensed by the pin 45 as flat spring 40A pushes pin 45 to the left.

The tape is next fed to the welding position 106 whereat a pair of

welding electrodes

44 and 46 are provided to attach the header leads 19 to the steel tape 11, as shown clearly in FIGS. 6 and 7. The drive for the welding operation is similar to that already explained in connection with the perforating operation. A vertically extending shaft 47 carries at its lower end a cam 48 which, upon rotation, bears against collars 49, attached to the welding quill 51, mounted for sliding movement by means of

brass bushings

52 and 53 in the upright supports 54 and 56. A spring 57 urges an inner shaft 58 coupled to the electrode 44 to the right shown in FIG. 7 to assure retention of the header leads in position and their positive engagement by the electrode 44. Effective sliding motion of the inner shaft 58 is assured by ball bushings 59 disposed toward either end of that shaft. A guide member 61 (FIG. 6), having a notch 62, is movable with the quill and assures that the leads will be held in their proper position during the welding operation. Additionally, a feeler 63 detects the presence or absence of a transistor header at the welding station. Accordingly, in the absence of a transistor header, the switch 107 controls an electrical circuit precluding the supply of welding current to the electrodes under such conditions, it being understood that the supply of welding current to the electrode is synchronized with the feeding operations. The welding and perforating operations take place simultaneously with the tape in its rest position. The ends of the header leads are welded toward one edge of the tape and the sprocket holes are formed toward the opposite edge of the tape.

The step-by-step advancement of the tape will now be explained with reference to FIG. 1. Coupled to the main driving mechanism is the rotary member 64 pivotally supporting a link 66 which it'reciprocates. Link 66, in turn, is in pivotal engagement with the crank member 67 at one end of the latter member. Crank 67 pivots about shaft 79. One end of a lever 68 is pivotally connected at an intermediate point to crank 67, while the opposite end of lever 68 is pivotally connected to a crank 71 which oscillates as the shaft 64 is rotated. Crank 71 is in fact part 'of the driving mechanism of a one-way clutch 72 wherein a small plate-like member 73 grabs and rotates the shaft 74 on counterclockwise movement and is free to move backwardly in the clockwise direc- 'tion.

Itwill be noted that lever 68 is slotted at 55 and spring '60 urges member 71 in a counterclockwise d1rection. Thus, it is the spring '60 which applies the motive force to member 71 when lever 68 is actuated. This arrangement provides yield inthe parts in case the tape'does not feed properly.

The lower end of the shaft '74 includes a sprocket wheel 76, the teeth of which engage the holes 43 of the tape 11 and drive the tape stepby step.

Driven in synchronism with the steel tape is the endless chain 16.- It will be noted that crank member 67 includes a one-way pawl and ratchet type of clutch 78 for driving the shaft 79.. The sprockets 17 attached to the shaft 79 are the driving sprockets for the endless chain 16, while similar sprockets 17 connected to the shaft 22 at the opposite end of the chain path are idlers. As the tape with headers attached reaches the right end of the apparatus, as viewed in FIG. 8, a take-off plate 105 assures positive removal of the headers from the blocks 14.

In order to assure separation of adjoining headers and eflicient header plating during later processing, a bending device 81 is provided for deflecting succeeding headers in opposite directions away from each other. This is done by means of a pair of gear-

like members

82 and 83 mounted respectively on shafts 75 and 80. It can be seen from FIGS. 1, 8 and 9 that these members are alternately arranged so that on rotation, the high part 84, including an arcuate surface 86, rides in the low part 87 of the opposite gear-like member; thus the leads of the successive headers are bent in opposite directions.

If the headers are not being properly drawn between the device 81 and the feed sprocket 76, they will tend to buckle, as shown in dotted lines at 91. On such occasions, a switch 92 is operated and a circuit to solenoid 31 is made, placing finger 93 in the path of finger 94 of the clutch 29 to stop operation of the apparatus as shown in FIG. 1.

Mounted on shafts 75 and (FIG. 9) are the sprocket feed wheel and follower 90, respectively, for assuring a positive grip on the tape during the bending of the leads.

As the tape leaves the device 81, it proceeds to an idler sprocket 96 mounted upon a horizontal axis. Sprocket 96 twists the strip from the vertical position it assumed in the bending device 81 to the horizontal position. The tape now proceeds downwardly through an opening 97 in the apparatus frame 9 to asuitably driven takeup reel 101. As illustrated in FIG. 10, in order to be certain that adjacent layers of transistor headers are protected from each other, a protecting tape 102 of polyethylene material is wound on the takeup reel 101 simultaneously with the metal tape 11. As is clearly seen in FIG. 11, the polyethylene tape comprises outer raised portions 103 which assure clearance for the headers protruding beyond one side of the tape.

The takeup reel is synchronized for rotation at a speed dependent on the feed of the tape through the perforating and welding apparatus.

the spirit of the invention.

What is claimed is: 1. Apparatus for attaching articles to a carrier comprismg: 7

two successive work stations,

means for feeding a flexible tape intermittently with rest periods to the two successive work stations,

a drive means for the tape feeding means,

means for feeding articles intermittently with rest periods to the two stations including an endless carrier with a series of slotted blocks carried thereby for receiving the articles,

a drive means for the article feeding means,

means for retaining the articles within the slotted blocks,

means at the first work station operable during the rest periods of both feeding means to perforate successively holes in the tape, and

means at the'second work station operable during therest periods of both feeding means to attach successively said articles directly to the major face of the tape in spaced relationship, with the articles extending from and being parallel to the major face of the tape and perpendicular to the major axis thereof.

2. Apparatus for attaching articles to a carrier comprising two successive work stations,

means for feeding a fiexible'tape of uniformly flat metallic material intermittently with rest periods to the. two successive work stations,

a drive means for the tape feeding means,

means for feeding articles intermittently with rest periods to the two work stations including an endless carrier with a series of slotted blocks carried thereby for receiving the articles,

a drive means for the article feeding means,

means for retaining the articles within the slotted blocks including a circular magnetic member at the loading position and retaining strips alongside the endless carrier,

means at one work station for perforating holes in the tape, and

means at the other work station including a pair of relatively movable electrodes at opposite sides of the tape operable during the rest periods of both feeding means to electrically weld successively the articles directly to the major face of the tape in spaced relationship, with the articles extending from and being parallel to the major face of the tape and perpendicular to the major axis thereof.

3. Apparatus according to claim 2 further including a feeler means to preclude the operation of the welding means except when an article is properly positioned for welding,

means for positively holding the article against the tape during the welding operation, and

means including a pilot pin to hold the tape in proper position when perforated.

4. Apparatus for attaching articles to a carrier comprising two successive work stations,

means for feeding a flexible tape of uniformly flat metallic material intermittently with rest periods to the two successive work stations,

a drive means for the tape feeding means including a clutch,

a drive means for the article feeding means including a clutch,

a common operating means for both drive means including a yieldable connection between the two said clutches,

means at one work station for perforating holes in the tape,

means including a pilot pin to hold the tape in proper position when perforated,

means at the other work station including a pair of relatively movable electrodes at opposite sides of the tape operable during each rest period of both feeding means to electrically weld an article d irect-, ly to the major face of the tape in spaced relationsln'p, with the articles extending from and being parallel to the major face of the tape and perpendicular to the major axis thereof,

feeler means to preclude the operation of the welding means except when an article is properly positioned for welding,

means for posi ively holding the article against the tape during the welding operation, and

means for operating the tape feeding means, article feeding means, attaching means, and perforating means in synchronism.

5. Apparatus for attaching articles to a carrier comprising:

a drive means for the tape feeding means including a clutch,

a drive means for the article feeding means including a clutch,

means at one work station for perforating holes in the tape,

means at the other work station including a pair of relatively movable electrodes at opposite sides of the tape operable during successive rest periods of both feeding means to electrically weld successively said articles directly to the major face of the tape in spaced relationship, with the articles extending from and being parallel to the major face of the tape and perpendicular to the major axis thereof,

means for positively holding the article against the tape during the welding operation,

means for operating the tape feeding means, article feeding means, attaching means, and perforating means in synchronism,

means for removing the articles from the blocks, and

means beyond the work locations for deflecting articles, including a pair of rollers, each having alternately arranged teeth and openings, the positions of the teeth and holes in the respective rollers being stag gered so that the articles are bent alternately in opposite directions.

6. Apparatus for attaching articles to a carrier comprising:

two successive work stations,

means for feeding a flexible carrier tape of uniformly fiat metallic material intermittently with rest periods to the two successive work stations,

a drive means for the tape feeding means including a clutch,

a drive means for the article feeding means including a clutch,

means at one work station including a pair of relatively movable electrodes at opposite sides of the tape operable during successive rest periods of both feeding means to electrically weld successively said articles directly to the major face of the tape in spaced relationship, with the articles extending from and being parallel to the major face of the tape and perpendicular to the major axis thereof,

means for positively holding the article against'th'e tape during the welding operation,

means at'the other work station for perforating holes in the tape,

means for removing the articles from the blocks,

means beyond the work locations for deflecting articles,

including apair' of rollers, each having alternately arranged teeth a-nd openings, the positions of the'teeth and holes in the respective rollers being staggered so that the articles are bent alternately in opposite directions,

a second tape feeding means for feeding the tape including detecting means between the two feeding means responsive to the accumulation of a predetermined amount ofslack tape material therebetween for controlling the operation of the apparatus, a reel of plastic tape having outer raised portions extending longitudinally along the tape, and a reel for simultaneously winding thereon the tape with the articles attached and the plastic tape in interleaved fashion, the plastic tape thereby providing spacing between adjacent layers of the tape with the articles attached.

, References Cited in the file of this patent UNITED STATES PATENTS Mecklenborg June 30, 1959

Claims

1. APPARATUS FOR ATTACHING ARTICLES TO A CARRIER COMPRISING: TWO SUCCESSIVE WORK STATIONS, MEANS FOR FEEDING A FLEXIBLE TAPE INTERMITTENTLY WITH REST PERIODS TO THE TWO SUCCESSIVE WORK STATIONS, A DRIVE MEANS FOR THE TAPE FEEDING MEANS, MEANS FOR FEEDING ARTICLES INTERMITTENTLY WITH REST PERIODS TO THE TWO STATIONS INCLUDING AN ENDLESS CARRIER WITH A SERIES OF SLOTTED BLOCKS CARRIED THEREBY FOR RECEIVING THE ARTICLES, A DRIVE MEANS FOR THE ARTICLE FEEDING MEANS, MEANS FOR RETAINING THE ARTICLES WITHIN THE SLOTTED BLOCKS, MEANS AT THE FIRST WORK STATION OPERABLE DURING THE REST PERIODS OF BOTH FEEDING MEANS TO PERFORATE SUCCESSIVELY HOLES IN THE TAPE, AND MEANS AT THE SECOND WORK STATION OPERABLE DURING THE REST PERIODS OF BOTH FEEDING MEANS TO ATTACH SUCCESSIVELY SAID ARTICLES DIRECTLY TO THE MAJOR FACE OF THE TAPE IN SPACED RELATIONSHIP, WITH THE ARTICLES EXTENDING FROM AND BEING PARALLEL TO THE MAJOR FACE OF THE TAPE AND PERPENDICULAR TO THE MAJOR AXIS THEREOF.