US2888735A

US2888735A - Article-assembling apparatus

Info

Publication number: US2888735A
Application number: US432767A
Authority: US
Inventors: Estyle D Hanson
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1954-05-27
Filing date: 1954-05-27
Publication date: 1959-06-02
Anticipated expiration: 1976-06-02

Description

June 2, 1959 E. D. HANSON ARTICLE-ASSEMBLING APPARATUS Filed May 2'7. 1954 3 Sheets-Sheet l Q Q\.\ NS mmit .25 w H .396 xmqzl 3:? N I IEQG 4 .3 F! Ifib: m N 2 I25 m INVENTOR. E. 0. HANSON ATTORNEY June 2, 1959 E. D. HANSON I 2,888,735

ARTICLE-ASSEMBLING APPARATUS SSh eetS-Sheet 2 Filed May 27, 1954 INVENTOR. E. D. HANSON BY ,4 TTORNEY June 2, 1959 Filed May 27. 1954 E. D. HANSCN ARTICLE-ASSEMBLING APPARATUS 3 Sheets-Sheet 3 i I56 93 INVENTOR. 37 llllilllllllllllllll 0 Q I/ ARTICLE-ASSEMBLING APPARATUS Estyle D. Hanson, Baltimore, Md., assignor to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Application May 27, 1954, Serial No. 432,767

7 (Ilairns. (Cl. 29-253) This invention relates to article-assembling apparatus, and more particularly to apparatus for positioning one element of an assembly in pressing contact with another element of the assembly.

In the manufacture of cartridge-type, point contact transistors, one of the critical operations involves the assembly of a crystal Wafer within the cartridge. The crystal wafer is pressed against the tips of two spaced electrodes which are designed to bear resiliently upon its surface. It is essential that the wafer be located precisely at a predetermined position within the cartridge, in order to. obtain a predetermined contact pressure between the surface of the crystal wafer and the electrodes.

It is an object of this invention to provide new and improved article-assembling apparatus.

, It is another object of this invention to provide new and improved apparatus for positioning one conductive element of an assembly in pressing contact with another conductive element of the assembly.

Article-assembling apparatus illustrating certain features of the invention may include a ram positioned to engage the first-mentioned element, a fluid-actuated cylinder for operating the ram, means for applying a fluid under pressure to the cylinder to cause the ram to move the first-mentioned element into initial contact with the other element, means for interrupting the flow of fluid from the supply means to the cylinder simultaneously with the completion of the initial contact, and means operated subsequently for injecting a predetermined amount of fluid into the cylinder to cause the ram to increase the contact pressure between the elements to a predetermined amount.

A complete understanding of the invention may be obtained from the following detailed description of an apparatus forming a specific embodiment thereof,-when read in conjunction with the appended drawings, in which:

- Fig. 1 is a partial section of a cartridge-type, point contact transistor, with parts thereof broken away for clarity; Fig. 2 is a plan view of an article-assembling apparatus, with parts thereof broken away for clarity;

' Fig. 3 is a vertical section taken along line 3-3 of Pi 2;

Fig. 4 is an enlarged, fragmentary section taken along line 4-4 of Fig. 2, with parts thereof broken away for clarity;

Fig. 5 is an enlarged, fragmentarysection taken along line 5-5 of Fig. 2;

Fig. 6 is a schematic representation of a hydraulic system forming part of the apparatus;

Fig. 7 is a schematic representation of an electrical control circuit forming part of the apparatus," and J Fig. 8 is a diagram of the sequence of operation of certain switches forming part of the apparatus during one complete cycle. a

Referring now to Fig. 1, there is illustrated a conventional cartridge-type, point contact transistor which includesatubular, metal cartridge 11. Positioned within ice one end of the metal cartridge 11 is a plug assembly designated generally by the numeral 12 comprising two spaced, rigid, metal pins 14 and 15 fixedly disposed in a cylindrical plug 16 of insulating material. The plug 16 is designed to fit closely within one end of the tubular, metal cartridge 11 and is held fixedly 'therewithin by internally projecting, annular crimped portions 18 and 19 formed in the cartridge.

The inner ends of the pins 14 and 15

carry electrodes

20 and 21, respectively, which are formed of resilient wire. In the finished transistor the

electrodes

20 and 21, conventionally referred to as the emitter and the collector, respectively, are spaced apart about 2 or 3 mils at their tips which bear resiliently on the surface of a small wafer 22 of a semi-conducting crystal material, such as germanium, having a surplus of conduction electrons (e.g. type N germanium). The crystal wafer 22 is soldered onto a cylindrical metal base contact 23, which is designed to be force-fitted within the open end of the cartridge 11 and to make electrical contact with the cartridge.

The apparatus shown in Fig. 2 is designed to adjust the position of the base contact 23 and the crystal wafer 22 within the cartridge 11 so as to obtain a predetermined contact pressure between the surface of the crystal Wafer and the

electrodes

20 and 21. This apparatus includes a circular, metal turret mounted rotatably on a vertical pedestal 32 (Fig. 3) for rotation in a horizontal plane. Intermittent rotation of the turret 30 is accomplished by means of an indexing mechanism designated generally by the numeral 34 including a drum type cam 35 driven through a gear reduction unit 36 by a constant speed, electric motor 3'7. The cam 35 is provided with a cam slot 39 arranged to engage successively each of a series of eight cam rollers 40-40 depending from and spaced equidistantly around the underside of the turret 30. Once during each cycle of revolution of the cam 35, the slot 39 engages one of the cam rollers 40-40 and indexes the turret 30 through an angle of 45.

Mounted fixedly on the turret 30 is an annular, metal support member 42 (Figs. 3 and 5) provided with eight equally spaced, generally cylindrical sockets 45-45, each of which is adapted to receive and retain a tubular cartridge 11 having a plug assembly 12 mounted fixedly within one end thereof. Each of the sockets 45-45 is provided with a longitudinal extending slotway 47 which serves to orient and hold the pins 14 and 15 of the plug assembly 12 in a generally vertical plane and permits the passage through the socket of the pin 15 which is bent and extends outwardly beyond the periphery of the cartridge 11. Mounted in the wall of each of the sockets 45-45 is a spring-pressed detent designated generally by the numeral 50, which is adapted to releasably engage the annular, crimped portion 19 formed in the wall of the cartridge 11. Mounted fixedly on the turret 3t) and within the annular metal support member 42 is an annular, flanged, metal backing member 52 (Fig. 5), the outer surface of which is spaced a short distance from the inner surface of the support member 42. The backing member 52 is provided with eight slots 54-54, each of which is" slot 54 without contacting the sides thereof. Mounteddirectly behind each of the slots 54-54 in the backing member 52 is a leaf-type, spring contactor 60 arranged to engage and make electrical contact with the outer end of the pin 14 on the plug assembly 12. The contactor 60 is electrically insulated from the metal turret 30, the metal support member 42 and the metal backing member Y52, and forms part of an electrical control circuit which will hereinafter be described in detail.

Positioned adjacent to the turret 30 is a hydraulic cylinder designated generally by the numeral 67. Slidably mounted within the cylinder 67 is a spring-biased piston 69 operatively connected to a ram 70. The free end of the ram 70 is cylindrical and has a diameter slightly less than the internal diameter of a tubular cartridge 11. After each indexing movement of the turret 30 a socket 45, having inserted therein a cartridge 11 provided with a plug assembly 12, is positioned adjacent to the hydraulic cylinder 67. In this position the longitudinal axes of the cartridge 11 and the ram 70* are aligned. The piston 69 is operable to an extended position to advance the ram 70 from right to left, as viewed in Fig. 5, toward and into the end of the cartridge 11, which is held immovably in the socket 45 against the backing member 52. The advance movement of the ram 70 is effected and controlled by the admission of hydraulic fluid under pressure through an entry port 72 provided in the cylinder 67. A compression spring 74 serves to return the piston 69 to its normal inoperative position when the fluid pressure is released, whereby the ram 70 is retracted.

Before a cartridge 11 positioned in the socket 45 is indexed into position adjacent to the hydraulic cylinder 67, a base contact 23 carrying a crystal wafer 22 is prepositioned partially within the end of the cartridge, as shown in Fig. 5. Subsequent operations of the ram 70, when the cartridge 11 is positioned adjacent to the operating station, are designed to force the base contact 23 and the crystal wafer 22 into the cartridge to a position wherein a predetermined contact pressure is obtained between the surface of the crystal wafer and the

electrodes

20 and 21.

Referring now to Fig. 6, there is shown schematically a hydraulic system for operating the ram 70. The system includes a reservoir 75 having an outlet 76 connected to the intake of a hydraulic pump 78 which is driven by an electric motor 80. The pump 78 discharges into an accumulator 82 of conventional design, which maintains a supply of hydraulic fluid under a substantially constant pressure. Associated with the accumulator 82 is a pressure sensitive switch 83, which controls the operation of the electric motor 80 in a manner such as to maintain the pressure of the hydraulic fluid within the accumulator substantially constant at a preselected value.

Communicating with the accumulator 82, in series with

valves

90 and 91, is a hydraulic line 92 which is normally in communication with the port 72 in the cylinder 67 through a solenoid-operated, three-way valve 93 controlled by a solenoid 95. The valve 90 is a manually operated, normally-open, flow control valve and the valve 91 is a normally closed gate valve controlled by a solenoid 96. interposed between the port 72 in the cylinder 67 and the three-way, solenoid-operated valve 93 is a variable-volume, auxiliary cylinder 100 (Figs. 2, 4 and 6). Slidably mounted within the auxiliary cylinder 100 is a piston 102 (Fig. 4) provided with a piston rod 103 pivotally connected to the free end of an arm 104 by means of a pin 105. The arm 104 is fulcrumed by means of a pin 107, which pivotally connects it to the upper end of an upright support bracket 110.

Movement of the piston 102 in a downward direction, as viewed in Fig. 4, may be effected by the energization of a pull-type solenoid designated generally by the numeral 112 having a movable plunger 114 which is hin'gedly connected to the arm 104 at a point intermediate of its ends. A compression spring 115 positioned on the cylinder 100 returns the piston 102 to its normal, raised position when the solenoid 112 is subsequently de-energized. The latter position is determined by the position of an adjustable stop 120, against which the lever arm 104 is normally engaged. The stop 120 is part of a conventional micrometer head, indicated generally at 122, which is supported by a bracket 123. The position of the stop 120 may be adjusted vertically by manually rotating an internally threaded collar 125. This arrangement permits very precise adjustments to be made in the volume of the auxiliary cylinder 100, the volume being dependent upon the normal position of the piston 192 when the solenoid 112 is de-energized.

Referring again to Fig. 6, the cylinder 67 may be disconnected from the hydraulic line 92 and connected to the reservoir by means of the three-way, solenoid-operated valve 93. Although the valve 93 normally connects the line 92 to the

cylinders

67 and 100, energization of its associated solenoid operates the valve 93 to permit the cylinder 67 to discharge the fluid therein into the reservoir 75 at atmospheric pressure as the compression spring 74 returns the piston 69 to its inoperative position.

Shown schematically in Fig. 7 is an electrical circuit for controlling the operation of the apparatus. The solenoid 96 of the solenoid-operated valve 91 is connected in series with a normally closed contact 132 of a sensitive relay 134 and a normally open contact 136 of a camoperated switch 137 (Fig. 2) across bus lines 140 and 141 energized from a suitable source of potential (not shown). The solenoid 112 is connected in series with a normally open contact 143 of a cam-operated switch 144 (Fig. 2) across the bus lines 140 and 141. Connected in parallel with the series arrangement of the contact 143 and the solenoid 112 is a series arrangement of the solenoid 9S and a normally open contact 146 of a cam-operated switch 147 (Fig. 2).

The switches 137, 144 and 147 (Fig. 2) are operated in a predetermined time sequence by means of cams 150, 151 and 152, respectively. The cams 150, 151 and 152 are keyed upon a shaft 155, which is driven through the gear reduction unit 36 and a suitable gear train designated generally by the numeral 156 by the electric motor 37. The sequence of operation of the switches 137, 144 and 147 by the cams 150, 151 and 152 during one complete cycle of operation is illustrated graphically in Fig. 8. The wavy lines represent portions of the cycle during which the respective switches 137, 144 and 147 are closed.

Also illustrated in Fig. 8 for reference is the portion of the cycle during which the indexing of the turret is accomplished by the cam 35. Referring again to Fig. 7, the sensitive relay 134 has a solenoid 160 which forms part of a normally incomplete circuit including a D.-C. supply, indicated schematically at 162, connected in series therewith. The positive terminal of the D.-C. supply 162 is connected to the contactor 60, which is engaged by the pin 14 on the plug assembly 12 when a cartridge 11 with a plug assembly 12 therein is positioned properly in the socket 45. The negative terminal of the D.-C. supply 162 is connected through the solenoid 160 to the base contact 23 and the crystal wafer 22, and to a common ground at 163. The grounding connection is made preferably through the metal support member 42 and backing member 52 with which the tubular cartridge 11 makes contact when engaged properly within the socket 45. The circuit, including the solenoid 160 of the sensitive relay 134, is completed when the crystal wafer 22 makes contact the electrode 20 (emitter), which contact has a rectifying action permitting a flow of current sutficient to operate the sensitive relay 134.

Operation Let it be assumed that the apparatus is already in operation with the electric motor 37 energized, and that it is at the beginning of a cycle of operation. The turret 30, which has just completed an indexing movement, supports a cartridge 11 having a plug assembly 12 in position adjacent to the ram 70 and cylinder 67. As shown in Fig. 5, the cartridge 11 has a base contact 23 carrying a crystal wafer 22 received partially within its unsupported end. The base contact 23 and the crystal wafer 22 have been prepositioned within the open end of the cartridge 11 by suitable loading means (not shown).

Immediately after the start of the cycle of operation, the cam 150 actuates the switch 137 to close its associated contact 136. When the contact 136 closes, the solenoid 96 is energized to operate the valve 91 to its open position. The opening of the valve 91 admits hydraulic fluid under a predetermined pressure to the cylinder 67 through the hydraulic line 92 and the three-way, solenoid-operated valve 93. T he hydraulic fluid also fills the auxiliary cylinder 100.

As the hydraulic fluid enters the cylinder 67 it advances the piston 69 and the attached ram 70 from right to left, as viewed in Figs. 2, and 6, whereby the ram engages the ba'se contact 23 and forces it further into the cartridge 11 until the surface of the crystal wafer 22 makes initial contact with the emitter electrode 20. Simultaneously with the making of the contact between the emitter electrode 20 and the surface of the crystal wafer 22, the circuit including the D.-C. supply 162 and the solenoid 160 of the sensitive relay 134 is completed to energize the solenoid 160. When the solenoid 160 is energized, it opens the contact 132, which in turn deenergizes the solenoid 96 to immediately close the valve 91. Thus, the forward movement of the ram 70 is stopped immediately upon the making of the contact between the emitter electrode 20 and the surface of the crystal wafer 22.

Subsequently, the cam 15% permits the contact 136 to reopen, after which the cam 151 actuates the switch 144 to close its normally open contact 143 and connect the solenoid 112 across the supply lines 144) and 141. When the solenoid 112 is energized, its associated plunger 114 is pulled downwardly, whereby the arm 104 pivots counterclockwise, as viewed in Figs. 4 and 6, to force the piston 102 downwardly. The downward stroke of the piston 102 results in the injection of a predetermined volume of fluid into the cylinder 67. This predetermined additive amount of fluid from the auxiliary cylinder 100 causes the ram '70 to advance a small predetermined distance to position the base contact 23 and the crystal wafer 22 accurately so that the

electrodes

20 and 21 bear resiliently on the surface of the crystal Wafer with a predetermined contact pressure.

The cam 151 subsequently causes the contact 143 to resume its normally open condition to de-energize the solenoid 112. Thereupon the piston 102 of the cylinder 100 is returned to its normal, raised position by the compression spring 115 mounted in the cylinder. Immediately thereafter the cam 152 operates its associated switch 147 to close its normally open contact 146, whereby the solenoid 95 is energized to operate the three-way valve 93 so as to connect the

cylinders

67 and 100 to the reservoir 75. The compression spring 74 returns the piston 69 to its normal inoperative position at the right hand end of the cylinder 67, whereby the ram 70 is retracted and the fluid previously contained in the cylinder is discharged at atmospheric pressure into the reservoir 75.

Subsequently, the earn 152 permits the contact 146 of the switch 147 to reopen, thereby de-energizing the solenoid 95 to return the three-way valve 93 to its normal position wherein it connects the hydraulic line 92 to the

cylinders

67 and 100. With the ram 711 retracted, the turret 31 is indexed during the remaining portion of the cycle when the cam slot 39 on the drum-type cam 35 engages the next cam roller 40 on the underside of the turret. With the cycle completed, another cartridge 11, having a base contact 23 and crystal wafer 22 prepositioned so as to be partially received within the end of the cartridge, is positioned opposite the ram 70 and the cylinder 67 in readiness "for the next'cycle'ofoperationed adjacent to the first-mentioned element, a fluid-.

actuated cylinder for operating the ram, means for supplying a fluid under pressure to the cylinder to cause the ram to move said first-mentioned element into initial contact with the other element, means for interruptingthe flow of fluid from the supply means to the cylinder simultaneously with the completion of said initial contact, an auxiliary cylinder having a predetermined volumetric capacity, means for filling the auxiliary cylinder with" fluid, and means'operated subsequently for injecting the predetermined amount of fluid from the auxiliary cylinder into the first-mentioned cylinder whereby the additional fluid thus introduced causes the ram to increase the contact pressure between the elements to a predetermined value.

2. Apparatus for assembling a wafer of a semi-conductive crystal within one end of a tubular shell having a resilient, point contact electrode mounted fixedly within.

the other end thereof, which comprises a ram positioned adjacent to the crystal wafer, a fluid actuated cylinder for operating the ram, means for supplying a fluid under' pressure to the cylinder to cause the ram to move the crystal wafer into initial electrical contact with the resilient electrode, electrically actuated means responsive to the establishment of said contact for interrupting immediately the flow of fluid from the supply means to the cylinder, an auxiliary cylinder having a predetermined volumetric capacity, means for filling the auxiliary cylinder with fluid, and means operated subsequently for in-' jecting the predetermined amount of fluid from the auxiliary cylinder into whereby the adidtional fluid thus introduced causes the ram to increase the contact pressure between the electrode and the crystal wafer by a predetermined amount.

3. Apparatus for assembling a wafer of a semi-conductive crystal within one end of a tubular shell having a resilient, point contact electrode mounted fixedly within the other end thereof, which comprises a ram positioned adjacent to the crystal wafer, a fluid actuated cylinder for operating the ram, means containing a supply of fluid, a conduit communicating with the fluid supply means and the cylinder, a valve interposed in the conduit between the fluid supply means and the cylinder, means for operating the valve to admit a flow of fluid into the cylinder to operate the ram to move the crystal wafer into initial electrical contact with the electrode, electrically actuated means responsive to the establishment of said contact for closing the valve immediately, and means actuated subsequently for injecting an additional, predetermined volumetric amount of fluid into the firstmentioned cylinder whereby the additional fluid thus introduced causes the ram to move the crystal wafer further into the shell by a predetermined distance suflicient to increase the contact pressure between the electrode and the crystal wafer by a predetermined amount.

4. Apparatus for assembling a wafer of a semi-conductive crystal within one end of a tubular shell having a resilient, point contact electrode mounted fixedly within the other end thereof, which comprises a ram positioned adjacent to the crystal wafer, a fluid actuated cylinder for operating the ram, means containing a supply of fluid under pressure, a conduit communicating with the fluid supply means and the cylinder, a valve interposed in series with the conduit for disconnecting the first-mentioned cylinderthe fluid supply means from the cylinder, an auxiliary, adjustable volume, fluid cylinder communicating with the conduit at a point between the first-mentioned cylinder and the valve, means for adjusting the volumetric fluid capacity of the auxiliary cylinder to a preselected amount, means for operating the valve to admit fluid under pressure from the supply into the first-mentioned cylinder and the auxiliary cylinder, whereby said fluid fills the auxiliary cylinder entirely and operates the ram to move the crystal into initial electrical contact with the electrode, electrically actuated means responsive to the establishment of said contact for closing the valve immediately to momentarily stop the movement of the ram and the crystal, and means for subsequently injecting additionally the predetermined volume of fluid contained in the auxiliary cylinder into the first-mentioned cylinder whereby the additional fluid thus introduced causes the ram to move the crystal Wafer further into the shell by a predetermined distance suflicient to increase the contact pressure between the electrode and the water by a predetermined amount.

5. Apparatus for assembling a water of a semi-conductive crystal within one end of a tubular shell having a resilient, point contact electrode mounted fixedly within the other end thereof, which comprises a ram, a fluid actuated cylinder for operating the ram, a rotatable turret, means for detachably mounting spacedly around the turret a plurality of such tubular shells, each having a crystal Wafer prepositioned partially within one end thereof, means operable periodically for indexing the turret to position one at a time the ends of the shells containing the prepositioned crystal wafers adjacent to the fluid operated ram, means operated each time a shell is positioned adjacent to the ram for supplying a fluid under pressure to the cylinder to cause the ram to move the prepositioned crystal water into initial electrical contact with the electrode fixedly mounted within the opposite end of the shell, electrically actuated means responsive to the establishment of said contact for inter rupting immediately the flow of fluid from the supply means, and means actuated subsequently for injecting a predetermined additional quantity of fluid into the cylinder whereby the additional fluid thus introduced causes the ram to move the crystal wafer to increase the contact pressure between the resilient electrode and the crystal water by a predetermined amount.

6. Apparatus for assembling a wafer of a semi-conductive crystal within one end of a tubular shell having a resilient, point contact electrode mounted fixedly within the other end thereof, which comprises a ram, a hydraulically actuated cylinder for operating the ram, means containing a supply of hydraulic fluid under pressure, a conduit communicating with the fluid supply means and the cylinder, a normally closed valve interposed in series with the conduit and normally disconnecting the fluid V supply means from the cylinder, an auxiliary cylinder communicating with the conduit at a point between the first-mentioned cylinder and the valve, a rotatable turret, means for detachably mounting spacedly around the turret a plurality of such tubular shells, each having a crystal wafer prepositioned partially within one end thereof, means operable periodically for indexing the turret to position one at a time the ends of the shells containing the prepositioned crystal wafer adjacent to the hydraulically operated ram, means for operating the valve each time a shell is positioned adjacent to the ram to admit fluid under pressure into the first-mentioned cylinder and the auxiliary cylinder, whereby said fluid fills the latter entirely and operates the ram to move the crystal into initial electrical contact with the electrode, electrically actuated means responsive to the establishment of said contact for closing the valve immediately to momentarily stop the movement of the ram and the crystal, and means for subsequently injecting a predetermined additional volume of fluid from the auxiliary cylinder into the first-mentioned cylinder whereby the additional fluid thus introduced causes the ram to advance the wafer a predetermined distance suflicient to increase the contact pressure between the electrode and the crystal water by a predetermined amount.

7. Article-assembling apparatus for positioning one element of an assembly in pressing contact with another element of the assembly, which comprises a ram connected operatively to the first-mentioned element, a fluid actuated cylinder for operating the ram, means for supplying a fluid under pressure, a conduit communicating with the fluid supply means and the cylinder, a valve interposed in series with the conduit for disconnecting the fluid supply means from the cylinder, an auxiliary cylinder communicating with the conduit at a point between the first-mentioned cylinder and the valve, means for operating the valve to admit a flow of fluid into both of the cylinders whereby the fluid fills the auxiliary cylinder to its eflective capacity and operates the ram to move the first-mentioned element into initial contact with the other element, means responsive to the establishment of said initial contact between the elements for closing the valve immediately, and means operated subsequently for injecting the predetermined additional amount of fluid from the auxiliary cylinder into the first-mentioned cylinder whereby the additional fluid thus introduced causes the ram to increase the contact pressure between the elements to a predetermined value.

References Cited in the file of this patent UNITED STATES PATENTS 2,072,087 Dewar Mar. 2, 1937 2,503,837 Ohl Apr. 11, 1950 2,649,560 Blair Aug. 18, 1953 2,757,440 Carman Aug. 7, 1956