US1658653A - Vacuum tube - Google Patents

Description

Feb, '2. 1928*, 1,658,653

M. RENNER VACUUM TUBE Filed April 21, 192'? Inventov: michael Renner,

His Attorney.

Patented Feb. 7, 1928.

UNITED STATES PATENT OFFICE.

MICHAEL Brennan, or" SGOTIA, NEW YORK. AssIGNon T GENERAL ELECTRIC oom- PANY, a oonrona rrolv on NEW YORK.

VACUUM TUBE.

The present invention relates to vacuum tubes and more particularly to suspenslon means 'for supporting the cathode element in such tubes. One of the objects of the inven- 6 tion is to provide a resilient cathode support which is so mounted in the vacuum tube that lateral movement of the cathode is prevented.

In the construction of vacuum tubes the amount of space between the cathode or filamentary electrode and the grid or control electrode is very limited and it sometimes happens thatwhen the filament is heated or subjected to vibration it will contact w1th the grid and thereby interfere with the op eration of the tube. Heretofore, it has been proposed to provide a suspension element for the filament which comprises a w1reextending through a rigidly supported insulator, one end of the suspension element being provided with a hook adapted to engage the filament, and the other end of the suspension means being engaged by a spring supported on the insulator. As thns arranged, however, the opening 1n the nsulator has to be made quite large to provide for free movement of the suspension means under all conditions and especially when the filament is heated. Making the opening 1n the insulator sufliciently large to provide for free movement of the suspension means permits the suspension means to pivot about the opening in the insulator and thereby allow suflicient lateral movement of the filament to short circuit the filament on the grid. Ac.-

cording to the present invention this pivoting movement of the suspenslon means has been prevented by the presence of a second insulator spaced from the first insulator and provided with means thereby efiectively preventing lateral movement of the suspension means and cathode.

The novel features which I believe to be characteristic of my invention are set forth with particularity in the appended claims. My invention itself, however, will best be pnderstood from reference to the follow ng specification when considered n cgnnect on with the accompanying drawing in which Fig- 1 shows a front elevation artlybroken away of a vacuum tube embo ying the teatures of m invention while F1gs. 2. and 3 are respectively a perspectivedetailed view an opening adapted ,to slid- 40 ably engage the upper end of the suspension and a cross sectional detailed view of the means for supporting the filamentary cathode, Fig. 3 being on a somewhat enlarged scale. y

Referring to-the drawing, I have indicated at 1 a vacuum tube of well known construction in which the anode 2 is supported on a split metal collar 3 mounted at one end of the tube while the filamentary cathode and grid are supported from the opposite end of the tube. An insulator 4 is mounted on. the collar 3 and is provided with openings 5 adapted to accommodate rods 6 which serve as a support for the grid or control electrode. Engagement of the rods 6 in these openings prevents lateral movement between the anode and control electrode. A second insulator 7 is mounted on rods 6 and held in position by small metal beads or other suitable means. Insulator 7 is provided with a plurality of open ngs 8 adapted to slidably accommodate suspension wires 9 each of which has a hook 10 at its lower end adapted to engage a filamentary cathode 11. A'

metal plate 12 having a downwardly extending flange 13 is rigidly secured to wire 9 by means of a perforated plate 14 which is v welded to wire 9 and plate 12. A second metal plate 15 restson insulator 7 and fits loosely on wire 9. Plate 15 is provided with r an upwardly extending flange 16 as clearly indicated in Fig. 3. A cylindrical spring 17 is mounted betwe'en'plates 12 and 15 and is normally held compressed by the tension of the filament 11. The flanged plate 15 prevents lateral movement of spring 17 and holds it in central position with respect to wire 9.

A third insulator 18 mounted on rod 6 and disposedbetween insulators 4 and 7 is normally spaced from'the latter by a plurality of metal collars or sleeves 19 mounted on rod 6. Metal beads 20 serve to maintain insulator 18 in spaced relation with insulator 4. Insulator 18 is provided-with a plurality of openings 21 in alignment with openings 8 in insulator 7 and adapted to accommodate wires 9.

(The spacing collars 19 are of such alength' that the maximum upward movement ofthe plate 12 due to expansion of the filament when heated, will carry the plate to a point just short of insulator 18. The distance between insulators 4 and 7' is sufiicient to permit maximum upward movement of wire 9 sulator 4.

Spring 17 on account of its cylindrical shape and the bearings provided by the plates 12 and 13 causes movement of the wire 9 in a substantially vertical direction and thereby tends to prevent binding of Wire 9 in the openings 8 and 21. However, if there is any tendency for lateral movement of the lower end of wire 9, such movement is effectively prevented by the engagement of the upper end of this wire with the sides of the opening 21 in insulator 18.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In an electric discharge device, a rigidly mounted insulator provided with an opening, a wire extending therethrough, said wire having means at its lower end adapted to engage a filamentary electrode, flexible means engaging said wire whereby a. tension may be applied to 'the filament, and means slidably engaging the upper end of said wire and adapted to limit lateral movement of said filamentary electrode.

2. In an electric discharge device, a pair of rigidly mounted insulators spaced apart from one another and provided with aligned openings, 0. wire extending through said without causing contact of wire 9 with in-v openings, a wire extending through openings and adapted to engage the cathode openings and adapted to engage a filamentary electrode, and'a spring mounted between said insulators and connected to said wire.

3. In an electric discharge device, a pair of rigidly mounted insulators spaced apart from one another and provided with aligneg element of the discharge device, a plate rigidly connected to said wire, and a spring mounted between said plate and one of said insulators.

4. In an electric discharge device, a rigidly mounted insulator having an opening extending therethrough, a plate having an opening in alignment with the opening in the insulator, said plate having an upwardly extending flange, a wire extending through said openings, said wire having a hook at its lower end adapted to engage a filament, a plate having a downwardly extending flange rigidly secured to said wire adjacent the upper end thereof, and a substantially cylindrical spring mounted between said plates and adapted to apply tension to the filament.

In witness whereof, I have hereunto set my hand this 20th day of April, 1927.

MICHAEL RENNER.

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