Патент USA US2118002код для вставки
May 17, 1938- ' R. G. BENNETT‘ 2,118,002 ELECTRON DI S CHARGE TUBE Filed April 8, 1937 INVENTOR, “fL/ ATTORNEY Patented May 17, 1938 2,1 l8,002 UNITED STATES PATENT OFFIQE 2,118,002 ELECTRON DISCHARGE TUBE Richard G. Bennett, Emporium, Pa., assignor to Hygrade Sylvania C orporation, Salem, Mass, a corporation of Massachusetts Application April 8, 1937, Serial No. 135,642 11 Claims. (01. 250—-2'7.5) This invention relates to electron discharge tubes and more particularly to shielding means for such tubes. A principal object of the invention is to pro 5 vide an improved form of getter shield for ra dio tubes and the like. A feature of the invention relates to an im proved means for securing a shielding member, for example a getter shield, in position within a radio tube or similar device. I A further feature relates to a radio tube of the metal envelope type wherein a getter shield of ceramic or other insulating material is employed in conjunction with a novel form of fastening means to hold the shield in place. Another feature relates to an improved form of metal clip for fastening an insulator member, for example, a getter shield, within a radio tube or the like. A still further feature relates to the novel or ganization, arrangement and relative location of parts which go to make up an improved radio tube of the metal envelope type. Other features and advantages not speci?cal 25 ly enumerated will be apparent after a considera under the trade name “Kovar” or of an alloy sold under the trade name “Fernico”. These al loys may be composed substantially of 18% co balt, 28% nickel and 54% iron and the glass beads may be of any suitable boro-silicate glass such for example one having the following approxi mate composition: 65% silica, 23% boric oxide, 7% sodium oxide and 5% aluminum. oxide. It will be understood of course that the invention is not limited to these particular materials so long as the glass beads can be sealed in a vacuum tight manner to the header. 20 Merely for purposes of illustration the inven tion is shown as embodied in a tube of the triode type comprising any well-known form of indi rectly heated cathode I3, a ?ne wire grid I4, and a tubular metal plate I5. The grid side rods I6, tion of the following detailed descriptions and the appended claims. ii are welded or otherwise fastened at their low er ends to the wires 6, 8 while the plate is elec While the invention will be illustrated as em trically connected to the lead-in wire 1. Wire ‘I is provided with an upwardly extending offset portion I8 which passes through a bore in the shield member 26 described hereinbelow, the up per end of wire l8 being connectedto the plate I 5. The heater ?lament 26 has its ends connected to the wires 4, 5 and the cathode sleeve I3 is connected to the wire 9. Preferably there are provided upper and lower insulator discs or spac ers 2|, 22 in the form of mica sheets perforated to receive the ends of the cathode sleeve and the various side rods. If desired a flexible extension bodied in a radio tube of the metal envelope type, 30 it will be understood that certainaspects of the invention are not necessarily limited to this type of tube and can be equally well embodied in a wide variety of tubes and similar devices. Ac cordingly in the drawing, 35 port wires 4 to I0 inclusive, for the electrodes of the mount._ Preferably, these wires are insulated from the header by glass beads I I which are her meticaliy sealed into the upper ends of the asso ciated metal eyelets I2, each of these eyelets be ing in registry with a corresponding perforation in the header and preferably welded thereto. Preferably also the eyelets are of an alloy sold Fig. 1 is a vertical sectional view of a metal radio tube embodying features of the invention and taken along the line I—I of Fig. 2. Fig. 2 is a sectional view of Fig. 1 taken along the line 2-2 thereof. 40 Fig. 3 is a side elevational view of the tube mount of Fig. 1, with the envelope removed. Fig. 4 is a detailed sectional view of part of Fig. 1, showing the shield clip in its normal posi tion. Referring to Figs. 1 to 3 the numeral I repre sents a base or header of suitable metal such for example as steel, iron, nickel or similar metal. Preferably, although not necessarily, the header I is ‘formed with a downwardly depending rim 50 2, and a centrally located exhaust tubulation 3 through which the device may be evacuated in known manner. The header I is provided with a series of perforations, preferably although not necessarily, circularly arranged, through which 55 insulatingly pass the various lead-in and sup or extensions may be attached to the disc 2| to engage the inner'face of the metal bulb 23 for the purpose of steadying the upper end of the mount. I As shown in the drawing, the bulb 23 is in the form of a metal cylinder of iron, steel, nickel or similar metal having a flattened top 24 and provided at its lower end ‘with a peripheral flange 25 which may be welded or otherwise fastened in a vacuum-tight manner to the member I. As is well-known in the radio tube art it is necessary 50 for various reasons to employ during part of the evacuation process a getter or clean-up agent which can be readily ?ashed or vaporized at the appropriate time so as to clean-up the residual gases or vapors that remain after the main evac 2,118,002 2 uation takes place. However in flashing this get ter it is highly important that it be prevented from depositing to any substantial extent on the glass beads H and thus reducing the insulation of the lead-in wires from the metal header i. For this purpose, there is provided a cylindrical shield 26 preferably, although not necessarily, of ceramic or similar insulating material which is adapted to surround the various lead-in wires. The shield 26 is provided at its upper end with a shoulder 2'! on which is seated the lower end of the plate electrode as shown clearly in Figs. 1 rial 34 attached thereto is then assembled over the mount and forced downwardly causing the upper free ends of the clips 29 to enter the corre sponding slots 32. The ?ange 23 is then welded to header I, and the completed tube is evacuated through tubulation 3 and heat treated and other wise subjected to the customary pumping sched ule. At the appropriate interval of the said. schedule the flame of a small torch is applied instantaneously against the bulb 23 adjacent the 10 getter 34 causing the latter to be ?ashed. Be cause of the shield 26, the vaporized getter ma and 4. Preferably the shield is also provided with terial is substantially prevented from depositing a series of recesses 28 to accommodate the glass on the glass beads II, or on the micas 2|, 22. After the tube has been completely evacuated and processed, the tubulation 3 is sealed off and any well-known form of prong or contact base is at tached to the header l. While certain speci?c materials and arrange 15 beads H. Since the shield is of insulating mate rial and the header l is of metal, ordinary meth ods of fastening the shield in place as for example welding, cementing,‘etc., are not feasible. There fore in accordance with the present invention 20 the shield is held in place by one or more sub; stantially L-shaped metal clips such as clip 29 the bottom 30 of which is welded or otherwise fastened to the header i. In order to accommo date the clips, the shield 26 is provided with notches 3i and in vertical alignment with the 25 notches the wall of shield 26 is provided with slots or grooves 32. As shown in Figs. 1 and 4, each clip 29 is bent to form' a shoulder 33 which is adapted to en gage the bottom of the slot 32 to prevent verti cal displacement of the shield. In order to hold the said shield ?rmly in place the end of clip 23 is bent to a V-shape so that when the tube 23 is ?tted over the mount the upper end of the 35 clip is forced inwardly from its normal position as shown in Fig. 4 to the position shown in Fig. l where it lies in the slot 32. The getter material in the form'of a small strip or sheet welded to the inner face of the tube 23 is indicated by the dotted rectangle 34, Fig. 3, and in order to en able the tube 25 to be assembled over the shield without disturbing the getter strip, the shield is provided with a ?at 35. It will be understood of course that the get ter instead of being in the form of a ?at metal ment of parts have been disclosed herein, it 2.0 will be understood that various changes and modi?cations may be made without departing from the spirit and scope of the invention. What I claim is: ' 1. An electric discharge tube comprising an 2.5 envelope consisting of a tubular member her metically sealed to a base member, a tube mount carried by said base member, leadj-in wires for said mount and sealed into said base member, getter material carried on the inner face of said . tubular member, and an insulating shield within the envelope for protecting said lead-in wires and seals from the vaporized getter material. 2. An electric discharge tube comprising an en velope consisting of a tubular member hermeti- : cally sealed to a base member, a tube mount carried by said base member, lead-in wires for said mount insulatingly sealed into said base member, a cylindrical shield of ceramic insulat ing material within the envelope surrounding 40 said lead-in wires, and means flexibly latching with said shield to fasten said shield to said base member. 3. In a device of the character described the combination of a tube mount, a metal base mem 45 strip or tab, may be in the form of a pellet en closed in a suitable getter cup or capsule which ber supporting said mount, lead-in wires insulat is welded to the inside face of bulb 23. Similarly the getter may be in the form. of a powder com-4 shield of insulating material for protecting said lead-in wires and seals from vaporized getter‘ material, and a flexible metal, clip carried by 50 pressed into a suitable pocket or depression on the inner face of the bulb as, is well-known in the art; In order to flash or vaporize the getter, heat is applied locally, as for example by a small torch, to the exterior of bulb 23 adjacent the 10 , cation of the getter, and if desired a suitable mark or indentation may be employed to indi cate, from the exterior of the bulb, the getter location. The assembly of the various elements of the tube is believed to be obvious from the fore 60 going and is in general as follows. The cathode and grid electrodes are assembled on the mica members 2!, 22 which are held in place on the grid side rods by suitable metal eyelets or the like. The grid side rods are welded to the cor responding lead-in wires 6, 8; the heater ?lament is connected to its lead-in wires 4, 5; and the cathode is connected to its lead-in wire 9. The shield 26 is then assembled in place and forced 70 downwardly to cause the shoulders 33 of clips 29 to latch in the corresponding recesses 32. The plate 15 is then assembled in the end of shield 26 and rests on the shoulder 21 being held against upward movement by wire l8 which is fastened 75 to the plate. The bulb 23 with the getter mate ingly sealed into said base member, a curved said base member and latching with said shield. 4. In a device of the character described the combination of a tube mount, a metal base mem ber supporting said mount, lead-in wires insu latingly sealed into said base member, a ceramic getter shield surrounding said lead-in wires, a metal clip fastened at its lower end to said base member, a shoulder formed on the wall of said shield, said clip being bent intermediate its ends to form a shoulder arranged to latch over the 60 shoulder on the shield. 5. In a device of the character described the combination of a tube mount, a metal base mem ber supporting said mount, lead-in wires insulat ingly sealed into said base member, a ceramic get ter shield for said lead-in wires and their seals, a slot in the wall of said shield, a flexible metal clip having an offset portion lying in said slot and engaging said shoulder to hold said shield ?rmly against said base member. 6. A device according to claim 5 in which the said shield is cylindrical and supports a tubular plate electrode at its upper end. '7. In a device of the character described the combination of a metal base member, a tube 2,118,002 ‘mount carried by said base member, a curved ‘ getter shield of insulating material disposed around the vertical axis of the mount, a shoulder formed on said shield, a tubular bulb sealed to said base member, and at least one metal clip having a pair of oiisets one engaging said shoul der to prevent vertical movement of said shield and the other engaging the inside of said tubular bulb to space said shield from said bulb. 8. In a device of the character described the combination of a metal header, a plurality of glass beads sealed to- said header, a wire sealed through each bead, a tube mount carried by said header and having its electrodes connected to 15 said wires, a metal bulb enclosing said mount and 10 hermetically sealed to said header, an insulating getter shield surrounding said wires, a plurality of recesses in said shield into which said beads partially extend, a plurality 01’ slots in the 3 shield wall, a corresponding plurality of ?exible wire clips each fastened to said header, each clip having a substantially V-shaped end with the apex of the V engaging the inner face of the bulb to force the end of the clip into a corre sponding slot in said shield. 9. A device according to claim 8 in which the shield is of ceramic material spaced from the wall of the bulb, and a quantity of getter mate rial is located between the bulb wall and the 10 shield. 10. A getter shield for a metal envelope radio tube comprising a tubular ceramic- member hav-. ing at least one slot in its outer faceto receive a wire clip. 15 11. A getter shield according to claim 10 in which the upper end of the ceramic member is shouldered to receive a tubular electrode. RICHARD G. BENNE‘I'I‘.