US2896118A - Discharge devices for electronic counting and like purposes - Google Patents

Description

July2l, 1959 D. J. WILLIAMS E'rAL 2,393,118

DISCHARGE DEvICEsFoR ELECTRONIC COUNTINYAND LIKE PURPOSES Filed Jan.. 5, 1956 2 sheets-sheet;

July 21,1959 D. J. WILLIAMS ET AL 2,896,118

DISCHARGE DEVICES FOR ELECTRONIC COUNTING AND LIKE PURPOSES Filed Jan. 5, 1956 2 sheets-sheet 2 ATTORNEY United States atent DISCHARGE DEVICES FOR ELECTRONIC COUNTING AND LIKE PURPOSES David `lohn Williams, Wollaton, Nottingham, and Kenneth Harold Westley, Dunkirk, Nottingham, England, assignors to Ericsson Telephones Limited, London, England Application January 5, 41956, Serial No. l557,571

Claims priority, application Great Britain September 7, 195'5 15 Claims. (Cl. S15-84.6)

The present invention relates to discharge devicesA for electronic counting and like purposes, such for example as line selection in telecommunication systems.

'The invention is concerned with gaseous discharge devices of the type comprising a plurality of` elongated electrodes arranged with their longitudinal axesparallel to one another in a least part of a ring and adapted to co-operate with a common electrode, the arrangement being such that when the device is connected in a suitable circuit a glow discharge can be causedv topass between each of the first-named electrodes and the common electrode in succession. Examples of devices of this type and of circuits in which they may be used are given in the specifications of British Patents Nos. 712,171 and 712,215.

In the type of discharge device with ywhich the present invention is concerned, and as described in these earlier specifications, the iirst-named electrodes are arranged in a plurality of groups each of three or more adjacent electrodes, the corresponding electrodes in the several groups being electrically connected together.

In order to ensure reliability in operation such devices need to be constructed with a high degree of accuracy and since they are usually required to be of small size their manufacture has presented considerable difficulty.

The present invention has for its principal object to provide a discharge device of the type set forth which is simpler and cheaper to manufacture than known devices of the type.

Another object of the invention is to provide a device of the type set forth which embodies a smaller number of dierent parts and which requires a smaller number of welded joints than known devices of the type.

Yet another object of the invention is to enable the insulation between the first-named electrodes and the common electrode to be improved in comparison with known devices of the same size without increase in cost of manufacture.

According to the present invention, in a discharge device of the type set forth, the first-named electrodes comprise a plurality of spiders arranged co-axially and spaced apart in a central region by insulating material, each spider having a plurality of arms bent throughy at least approximately a right angle so that at least parts of the arms are disposed parallel to one another in a ring, and the spiders being staggered circumferentially relatively to one another whereby each arm of one spider lies between two arms of the other or others of the spiders.

Preferably all the first-named electrodes are formed by the spiders and the spiders are advantageously made alike, excepting, in some cases, as to the lengths of the arms thereof.

The insulating material is preferably in the form of ceramic blocks, a plurality of these blocks being alike.

All the rst-named electrodes may pass through apertures in an insulating block, preferably of ceramic, these apertures serving to locate the electrodes relatively to ice one another and relatively to the common electrode which is supported by a member passing through a central aperture in the block.

Other features of the invention will be apparent from theV following description of one embodiment thereof with reference to the accompanying drawings inwhich Fig. l is a view in front elevation of a discharge device according to the invention,

Fig. 2 is a plan view of the device of Fig. 1 without the envelope,

Fig. 3 is a view in perspective from the rear of the device in Fig. l,

Fig. 4 is an enlarged view in section on the line 4-4 of Fig. 2,

Fig. 5 is an enlarged plan view of a blank used in formingV the spiders in the device of Figs. l to 4,

Figs. 6 and 7 are views in plan and elevation respectivelyV of the finished spider formed from the blank in Fig. .5, and

Fig. 8 shows a fragment of the view of Fig. 4, embodying a modification.

Referring to the drawings, the discharge device cornprises a vitreous envelope 10 sealed to a vitreous foot 11, the envelope being filled with a suitable gas at reduced pressure'.

The electrode assembly, best shown in Fig. 4, is built upA with the aid of a number of blocks of ceramic, such as unglazed porcelain. The lowest block 12 is hollow at its upper part and accommodates three like blocks 13, 14, and 1S arranged, with the aid of bosses and recesses', to nest into one another as shown. The uppermost block 16 has a boss 16 nesting, in a recess in the block 15.

Referring to Figs. 5 to 7, three blanks of pure nickel of the shape shown in Fig. 5 are used. In the embodiment being described, what have been referred to as the first-named electrodes are thirty in number arranged in ten groups of three electrodes. Each blank, therefore, has ten radially-extending arms 17. The arms 17 extend from a hub portion 18 having a central aperture 19. The arms 17 are bent through' a right angle to form a structure such as is shown in Figs. 6 and 7.

The hub portion 18 of one spider and a mica disc 20 are arranged between the blocks 15 and 16, the boss 16 extending through the aperture 19 in the spider and through a corresponding aperture in the mica disc and serving to locate the spider and disc relatively to the block 16. The mica disc 20 is provided with ears 21 which are adapted to engaged the inside of the envelope 10 and locate the electrode structure and is also provided lwith thirty uniformly-.spaced apertures registering with apertures 22 in the block 16'. The arms 17 project upward through every third one of these apertures.

A second spider as shown in Fig. 5 has its hub portion 18 located between the blocks 14 and 15 and its arms 17 extending upward through apertures in the mica disc 20 and block 16 adjacent those traversed by the arms 17 in a counterclockwise direction as seen in Figure 2. A third spider as shown in Fig. 5 has its hub portion 18" located between the blocks 13 and 14 and its arms 17 extending upward through the remaining apertures in the mica disc 20 and block 16.

The arms 17 of the three spiders are cut to different lengths such that the ends of the arms lie in a plane. This may be done either by stamping out spiders of different size, or by forming all the spiders of the size ofthe largest and reducing the lengths of the arms in two of the spiders.

A pure nickel wire 23 is spot-welded to the spider hub 18" and extends downward through a gap between the blocks 13, 14 and 15 on the one hand and the block 12 on the other hand. The lower end of the wire 23 is spotjwelded to a lead-in wire 24 which is sealed throughv the foot 11 and connected to one'of the terminal pins Z5".

Other wires similar to 23 connect the other two spiders with others of the terminal pins 25: the lower end of one of these wires is shown at 26 in Fig. 4 but the upper part of this wire has been omitted for the sake of clearness. The connecting wires suchl as 23 and 24 serve to support the electrode structure upon the foot 11. A pure nickel rod 27 passes through aperturesin the blocks 13, 14, 15 and 16 and near its upper end carries a common electrode 28 of pure nickel. A anged sleeve 29 is welded to the rod 27 and the ange lies between the blocks 12 and 13. A'ceramic tube 30 is located around the rod 27v between -the block 16 and the electrode 28 and in this way the electrode structure is held firmly toi Thering of thirtyapertures 22 in the block open .1 f at their upper ends, that is the ends nearer the discharge paths between the outer electrodes and the common electrode, into an annular groove 31 and the central aperture opens into a circular recess 32. Both the groove 31 and the recess 32 are thus disposed in the upper face of the block 16 which is exposed toward the discharge space between the outer electrodes and the common electrode. At each of the apertures 22 a recess is defined in part by the opposed walls of the groove 31, these walls being spaced from the outer electrodes. The circular recess 32 has a wall facing inwardly toward, but being spaced from, the conductor 27 which supports a common electrode. This groove and recess provide a substantial increase in the path length for surface leakage between the rod 27 and the outer electrodes and give a substantial improvement in insulation after sputtering. The walls of the groove 31 and recess 32 may be tapered instead of parallel to the tube axis as shown.

The apertures of the ring of apertures and the central aperture in the block 16 are constricted immediately below the groove 31 and recess 32, these constrictions providing good locating means for the electrodes.

A getter is provided in known manner in a suitable recess in the block 12,v although this is not shown.

Although in the embodiment described the hub portions of the spiders are at and perpendicular to the axis of the device this is not necessarily the case. The hub portions may be of frusto-conical shape and the arms are then bent through an angle differing from a right angle, usually less than a right angle.

It will be seen that the discharge device described has l few different parts. Thus the electrodes of the ring are constituted by three spiders which are like except for the lengths of their arms and three of the five ceramic blocks, namely blocks 13, 14 and 15, are alike. Only one weld is required between each spider of ten electrodes and its lead-in wire such as 23 or 26. The assembly of the device with suitable accuracy is also relatively simple.

The device described may be used in many diterent circuits such for example as those described in the aforementioned earlier patent specifications. The outer ring of electrodes preferably constitute the cathodes and the common electrode the anode but the opposite arrangement may be used.

In a modification of the above-described device illustrated in Fig. 8 the spiders are alike and all have arms 34, 34 and 34" of the same length. The effect when viewed as in Fig. 7 is that the ends of the arms, instead of lying in a plane, form a saw-tooth pattern. The common electrode 28 is then arranged substantially in or below the plane in which the ends of the shortest arms lie. In Fig. 8 itis shown below that plane.

We claim:

1. A gaseous electric discharge device comprising a sealed envelope and within said envelope a plurality of v Y' elongated electrodes disposed with their longitudinal axes parallel to one another in at least part of a ring, a common electrode in electric discharge relationship with said elongated electrodes, said elongated electrodes being constituted by arms of a plurality of spiders each having a hub portion, each said hub portion having bearing surfaces in planes perpendicular to said axis, and insulating spacer means located between and in engagement with said bearing surfaces of adjacent spiders and supporting the latter -relative each other, the arms of one spider being interleaved with the arms of another spider.

2.-A'discharge device according to claim 1, wherein said arms have ends all lying substantially in a plane.

3. A discharge, device according to claim l, wherein said spiders are alike.

4. A gaseous electric discharge device comprising an hermetically sealed envelope and within said envelope a plurality of elongated electrodes disposed with their longitudinal axes parallel to one another in a generally curved pattern, a common electrode in electric discharge rela- :tionship with said elongated electrodes, said elongated electrodesbeing constituted by arms of a plurality of spiderseach having a hub portion, said spiders being alike except for the length of said arms, said arms having ends terminating substantially in a plane, and insulating spacer means located between and engaging the hub portions ofadjacent spiders and supporting the latter relative each other, the arms of one spider being interleaved with the arms of another spider.

5. A gaseous electric discharge device comprising a iirst apertured insulating block, said block including apertures uniformly spaced in a ring and an aperture at the center of said ring, at least two further centrally apertured insulating blocks, at least two electrically conducting spiders each having an apertured hub portion and a plurality of elongated arms projecting at least approximately at right angles from said hub portion with the longitudinal axes of said arms parallel to one another, the hub portion of one of said spiders being located between and supported by said first apertured block and one of said further apertured blocks, the hub portion of another of said spiders being located between and supported by the last-named apertured block and another of said further apertured blocks, and the arms of said spiders extending through the apertures in said ring with the arms of one spider interleaved with the arms of another spider, a common electrode in electric discharge relation to said arms, and a conducting member connected with and supporting said common electrode and extending through the central apertures in said blocks and through the apertures in said spiders.

6. A discharge device according to claim 5, wherein said arms have ends all lying substantially in a plane.

7. A discharge device according to claim 5, wherein said spiders are alike.

8. A discharge device according to claim 5, wherein said further blocks are alike.

9. A discharge device according to claim 5, wherein each of the apertures in said ring terminates in a recess on the side of said rst insulating block remote from said further blocks.

l0. A discharge device according to claim 9, wherein said recesses are constituted by an annular groove.

1l. A discharge device according to claim 5, wherein Vthe central aperture in said first block terminates in a recess on the side of said first insulating block remote from said further blocks.

l2. A discharge device according to claim 5, wherein at least one of said blocks has a boss engaged in a recess in another of said blocks.

13. A gaseous electric discharge device comprising a sealed envelope and a plurality of elongated electrodes disposed with the longitudinal axes thereof parallel to one another within said envelope, a common electrode disposed in electric discharge relationship with said elongated electrodes, and a block of insulating material having a plurality of apertures for locating said elongated electrodes relatively to one another, each of said elongated electrodes passing through one of the apertures in said block, and said block having a face exposed toward the discharge space between said electrodes, said block having a recess dened at least in part by opposed walls in said face at the termination of each of said apertures to maintain improved insulation against electrical surface leakage thereon, said Walls being spaced from the elongated electrode at each of said apertures.

14. A discharge device according to claim 13, wherein said recesses are constituted by a groove extending over the apertures.

l5. A discharging device according to claim 13, comprising a conductor supporting and providing electrical connection to said common electrode, said conductor traversing a further aperture in said apertured block, said elongated electrodes being disposed in a ring around said conductor, and said further aperture terminating in a recess defined at least in part by a wall inthe face of said block to maintain improved insulation against electrical surface leakage between said elongated electrodes and said conductor, said last-mentioned wall facing inwardly toward said conductor and being spaced therefrom.

References Cited in the ile of this patent UNITED STATES PATENTS 2,524,213 Wales Oct. 3, 1950 2,633,550 Stieritz Mar. 31, 1953 2,651,004 Acton Sept. 1, 1953 2,693,552 Steinberg Nov. 2, 1954

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