US2843445A

US2843445A - Getter flashing device

Info

Publication number: US2843445A
Application number: US557308A
Authority: US
Inventors: Gene A Coltrin
Original assignee: Sylvania Electric Products Inc
Current assignee: GTE Sylvania Inc
Priority date: 1956-01-04
Filing date: 1956-01-04
Publication date: 1958-07-15
Anticipated expiration: 1975-07-15

Description

July 15, 195 8 H e. A. COLTRIN 2,843,445

GETTER FLASHING DEVICE Filed Jan. 4, 1956 I 2 Sheets-Sheet 2 l I I mum Q 1 INVENTOR GENE A. COLTRIN ATTO United States Patent O GETTER FLASHING DEVICE Gene A. Coltrin, Hollidaysburg, Pa., assignor to Sylvania Electric Products Inc., a corporation of Massachusetts Application January 4, 1956, SerialNo. 557,308

Claims. (Cl. 316-'30) This invention relates to getter flashing devices and methods of getter flashing.

Prior to this invention two common methods of flashing the getter in electronic tubes had been used. In one, the getter is flashed during the exhaust cycle and immediately after bombardment of interior elements with high frequency currents to heat them to drive off occluded gases and immediately after excess filament heating to properly condition the cathode. Any imperfection in the vacuum system of the exhaust machine will allow the gas pressure in the tube to increase between the time the tube is flashed and the time when it is finally sealed; in addition, the described method does not provide sufficient active gettering material at the time the bulb is tipped since some of it had been exhausted prior to tipping off of the bulb; also gases liberated from the molten glass are left free in the tube and adversely affect initial characteristics of the tube and tube life.

The other common method used in tube manufacture is to flash the getter after the tube is tipped off and cooled. This method reduces the gas content, but since the mount structure is cold, getter material easily condenses on the insulating spacers in the tube and creates leakage paths between electrodes. In addition, some gases which were left in the tube after tipping-off may be adsorbed into the tube parts as they cool completely and these gases will not be readily available to combine with the active getter material when the tube is flashed, but may be subsequently liberated when the tube is aged or put into use.

The main object of this invention is to provide a means to flash the getter during and immediately following the tipping off operation. During these times very little of the getter material is exhausted from the tube and, since all the parts are hot, the getter will readily combine with the gases liberated from the glass and with such residual gases as are left due to incomplete exhaust. This flashing occurring at a time when the interior tube parts are still maintained at a high temperature will result in marked decrease in condensation on the insulators of getter material. The bulb which is then exposed to the ambient atmosphere will be cooler than the interior portions of the tube, such as the insulators, and will receive the getter condensation rather than the hot mount within the bulb. A further object of the invention is to provide for a method of tube getter flashing which shall result in retaining within the tube most of the getter material originally in the tube but yet result in little, if any, deposits of getter material on the mount structure within the tube.

Other objects will become apparent after considering the following specification and claims in conjunction with the accompanying drawings in which Fig. l is a side elevation of the flashing device, showing the tip-off station, a flasher coil surrounding a tube, and transfer mechanism to remove a tube from the tip-off station.

Fig. 2 is a view similar to Fig. 1 but showing the transfer mechanism in a shifted position of parts ready to drop a completed tube onto a chute, the flasher coil being tilted out of the path of falling movement o f the bulb.

Fig. 3 is a plan view of the flasher and transfer mechanism with parts in the position of Fig. 1.

Fig. 4 is a view similar to Fig. 1 but from the opposite side of the structure, and

Fig. 5 is a view looking to the right at Fig. 4 but with the bombarder coil broken away.

Now referring to the drawings in greater detail, at 10 there is indicated a table on which is fixedly mounted a standard 12 to which is attached a webbed bracket 14 at the upper end of which is a bearing 16 within which is journaled a stub shaft 18.

Aflixed to an enlarged portion of the shaft 18, see Fig. 5, as by a pin 20 is a tube transfer arm 22 to which is secured an angled extension 24 supporting articulated

jaws

26 and 28 pivoted at 30 on the extension. The two jaws are normally resiliently held together by a spring 32 tensioned between pins 34 carried by the jaws. One of the articulated jaws, jaw 28, is provided with an operating arm 36 against which may be thrust an operating rod 38 pivoted to a bell crank lever 40 via a link 42. The bell crank lever is pivotally mounted as by the pin 20 in a slot in the end of shaft 18 and is normally held against an operating wear plate 44 by a spring 46 coiled about the rod 38 and reacting between one of a pair of bearings 48 for the rod and a stop 50 fixed on the rod. The wear plate is shaped to enable the plate to swing past the bearing 16 and arm 22 but yet to provide for continuous engagement of an antifriction roller 51 on the free end of bell crank lever with the plate as the jaws are swung around the axis of shaft 18. The plate 44 is mounted on a free end of a bell crank lever 52 rotatable on a pivot 54 in the bracket 14. The other end of the lever 52 is connected to a-link 56 which in turn is connected to and operated by a lever 58 whose movement is controlled by a cam 60 mounted on a cam shaft 62 on the machine. The cam shaft is synchronized for movement with a turret 64 supporting exhaust ports 66, as is conventional in the art. When the plate 44 is oscillated about the pivot 54, the rod 38 will effect the opening of the

jaws

26, 28 and release any tube held by the jaws to allow it to drop upon a carry off chute 67. To rotate the jaws about the axis of shaft 18, an arm 68 having a collar 70 pinned to the shaft 18 is connected to a link 72 operated at .its lower end by a pivotally connected lever 74 in turn operated by a cam 76 fixed on the cam shaft 62. Oscillation of shaft 18 will therefore move the jaws between the down-position shown in Figs. 1 and 3 and the up-position shown in Figs. 2, 4, and 5. During this oscillation of shaft 18 the bell crank 40 will oscillate therewith with its antifriction roller 51 at all times opposed to the plate 44. The cams 60 and 76 are so contoured that the plate 44 will be oscillated toward the free end of the bell crank when the jaws are in the fully raised position, thereby operating the jaws and releasing the tube when in that position. The cam 60 also functions to swing the plate 44 to open the jaws before the jaws have been swung down over a bulb on the exhaust port 66 of the turret 64 and to retract the plate to allow the jaws to close on the bulb before the jaws swing upward. During the sealing 01f operation of the tubulation eifected by the fires from burners 78 held on the ends of an adjustable bar 79, it has been customary to draw the bulb upwardly while the tubulation is held tight in the exhaust port. For this purpose there is. provided a cup 80 at a level below the bottom of the bulb during turret indexing and open at its side (-not shown) to enable the turret borne tube and tubulation to index into position relative to the cup. The cup is mounted on a rod 82 slidable in a sleeve 84, the rod being resiliently held in telescoped relation with the sleeve by a spring 86 tensioned between the two. The sleeve is mounted on a bracket 88 on the upper end of a post 90 vertically reeiprocatable in the standard 12. At the lower end of the post is a link 92 connected to a lever 94 operated by a cam track 96 in a cam 98 fixed onthe shaft 62. To prevent rotation of the bracket 88, the same has fixed thereto a guide bar 100 slidable in a slot between lugs 102 on the standard 12. During the tipping-ofl? operation, the cup engages beneath the bulb while flames are applied to the exhaust tubulation and while the bulb is still under exhaust. The bracket 88 rises to cause the cup to engage the bulb, the spring 86 in the meantime being stretched and put under further tension since initially the bulb does not move upward with the bracket. Eventually the tubulation softens sufiicie'ntly to allow the spring 86 to contract and to quickly assist in separation of the tubulation sections above and below the heated areas, the complete separation being effected by the continued rise of the bracket 88.

So far the exhausting and tip-01f structure and operation have been described. Now attention is directed to the associated getter flashing structure and operation.

Mounted on the arm 68 is a bent bar 104, the same being aflixed to the arm 68 as by screws 106. To this bar is aflixed a second wider bar 108 fixedly carrying at its free extremity one leaf of a two-leaved hinge 110, the other leaf being fixed to a small rectangular plate or platform 112. At an outer end of this platform is a cam follower roller 114 and at the other end is an insulating block 116. The roller 114, as the shaft 18 is oscillated from the position in Fig. 1 to the position in Fig. 2, will engage a cam iron 118 fixed on the bearing 16 and pivot the platform 112 and the block 116 to the position shown in Fig. 2. The block 116 supports the tail ends of a flasher induction coil 1 20, conventionally made of hollow brass tubing through which there is a circulation of cooling fluid with conductive insulated hollow flexible leads 122 conducting said fluid as well as high frequency current to and from the coil. The cam 118 is so positioned that the platform will tilt the coil 120 ufliciently out of the way of the tube held by the jaws to permit the tube unhindered movement onto the chute 67 when the

jaws

26, 28 release the tube. The weight of the coil 120 and appurtenances will bias the platform to the position of Fig. l in the down position of bar means 104, 108. The cam 76 is so mounted on shaft 62 that it will bring the bombarder coil over the dome of the bulb in concentric relation with the axis of the bulb and the open jaws around the bulb just as the seat 80 rises, the coil being then directly in line with and above the jaws. The cam 60 then permits closure of the jaws on the bulb. Current to the coil is under control of a switch 124 operated by cam 126 on the shaft 62 and is supplied to the coil substantially from the time that the jaws and coil reach the position shown in Fig. 1 until the coil reaches the position shown in Fig. 2. Thus heating of the getter material is initiated while the tube is still under exhaust with flashing taking place just immediately prior to tipping off, and heating of the getter support continues during substantially all of the time until the coil is displaced to the position shown in Fig. 2. All of the interior parts of the tube during and immediately after flashing are still hot due to previous bombardment of electrode elements in the tube and excess filament heating as explained previously. But the bulb, due to exposure to the ambient atmosphere, is much cooler than the interior contents. Therefore getter material will tend to condense on the interior of the bulb rather than on the insulators or electrodes within the bulb. Thus interelectrode leakage due to getter deposi tion is materially reduced, while yet little, if any, of the getter material is exhausted from the tube prior to tip-off.

Although the preferred embodiment discloses a flasher coil movable with and relative to a transfer means, it shouldbe obvious that other flasher means Within the scope of the claims may be utilized. So, too, other 4 transfer mechanism than that preferred and shown may be utilized, so long as they fall within the scope of the appended claims. The mechanism herein disclosed is exemplary, the invention being defined in the appended claims.

What is claimed is:

1. In mechanism for finishing tubes involving tippingoff the same and flashing the getter therein, the combination comprising: a tip-off mechanism, a carry-off device, a device for transferring a tube from said tip-off mechanism to said carry-off device a flasher device, movable with the transfer device, and means operative immediately before said tipping-off and during operation of said transfer device to energize the flasher device to flash the getter within the tube.

2. In mechanism for finishing tubes involving tippingoff the same and flashing the getter therein, the combination comprising: a tip-off mechanism, a carry-off device, a device for transferring a tube from said tip-ofl mechanism to said carry-oft device, a flasher device mounted on and movable with the transfer device, and means operative immediately before said tipping off and during operation of said transfer device to energize the flasher device to flash the getter within the tube.

3. In mechanism for finishing tubes involving tippingoff the same and flashing the getter therein, the combination comprising: a tip-off mechanism, a carry-off device, a device for transferring a tube from said tip-off mechanism to said carry-off device, a flasher device movably mounted on and movable with the transfer device, means operative immediately before said tipping-off and during operation of said transfer device to energize the flasher device to flash the getter within the tube, and means to move the flasher device relative to the transfer device and away from the tube at the end of operation of the transfer device.

4. In mechanism for finishing tubes involving tippingofl the same and flashing the getter, the combination comprising: a tip-off mechanism, a carry-off device, a transfer device for transporting a tube from the tip-off mechanism to the carry-off device, said transfer device including a pivoted arm with bulb engaging jaws at the free end of the arm, a bar movable with and parallel to the arm and, a platform pivoted to an end of the bar, a cam follower on the platform, a fixed cam engaged by said follower when the bar is pivoted, and a flasher coil fixed to said bar, said coil in one position of the am being directly aligned with the jaws.

5. In mechanism for finishing tubes involving tippingoff the same and flashing the getter, the combination comprising: a tip-off mechanism, a carry-off device, a transfer device for transporting a tube from the tip-off mechanism to the carry-off device, said transfer device including a pivoted arm with bulb engaging jaws at the free end of the arm, .bar'm'eans pivoted coaxially with the arm and provided at its free end with a pivoted platform with said platform having a portion extending over the bar means and a second portion extending beyond the bar means, a cam follower on said second portion, a fixed cam engageable by said follower, and a flasher coil fixedly carried by said platform, said coil being concentric with the axis of a tube held by said jaws when the first portion of the platform rests on the bar means and being out of the way of the tube when the follower engages the fixed cam.

References Cited in the file of this patent UNITED STATES PATENTS 1,028,636 Thatcher June 4, 1912 1,461,155 Madden et a1 July 10, 1923 1,596,733 Higgins Aug. 17, 1926 1,626,679 Kelly May 3, 1927 1,894,948 Espe et a1 Jan. 24, 1933 2,006,771 Kayko et al. July 2, 1935 2,673,784 Snyder Mar. 30, 1954