US2835843A - Tube mount support - Google Patents

Description

May 20, 1958 W. '1'. MlLus TUBE MOUNT SUPPORT Filed July 26, 1955 FIG.!

INVENTOR WALTER T. MILLIS,

TUBE MGUNT SUPPORT Walter Townsend Militia, Owensboro, Ky., assignor to General Electric Company, a corporation of New York Application July as, 1955, Serial No. 524,563

8 laims. (til. 313-292) My invention relates to electric discharge devices and pertains more particularly to new and improved means for supporting an electronic tube mount in a tube envelope.

It is the general practice in supporting the mount structure of an electronic tube in the envelope of the tube to use devices commonly known in the industry as snubbers. Snubbers have been provided to support the mount by being fastened to or made a part of the mount structure and extending outwardly and engaging the inner walls of the envelope. A common type of snubber currently in use in receiving tube types and the like is a bluntpointed projection punched from, or otherwise formed integr lly with, and on the peripheries of mica disks or electrode spacers, which comprise parts of the tube mount. This type of snubber, from the standpoint of cost, is decidedly advantageous over other types that are formed separately and have to be subsequently attached to the tube mount. The integrally formed projections heretofore provided have, however, the disadvantages of being inflexible and of having a tendency to be crushed when inserted into a tube envelope. Such crushing results in a substantial reduction in the dimensions of the projection and thus a loose fit or poor mount rigidity follows, causing undesired microphonics and rattling of parts when the tube is tapped or otherwise vibrated. The tendency toward crushing of the snubber is increased when the envelope is out of round or when the eifective diameter of the open end of the tube bulb, through which the spacer mustpass on assembly, is for any reason smaller than that of the normal straight wall portion of the bulb. Further, forces tending to crush the tips of the snubbers occur during shipping and handling of the completed tubes.

Still further, when the spacers are formed of mica or the like, the crushing or breaking of the snubbers results in the undesirable presence in the tube of flakes or particles of the spacer material which tend adversely to affect tube operation.

Accordingly, the primary object of my invention is to provide a new and improved tube mount support means.

Another object of my invention is to provide a new and improved snubber structure adapted for insuring a satisfactory fit thereof in an envelope and thereby avoid mount rattle and tube noise.

Another object of my invention is to provide a new and improved snubber structure adapted for avoiding crushing of any portions thereof thereby to insure a satisfactory fit in an envelope and to avoid the presence in the envelope of undesired loose particles of matter which would tend adversely to affect the operation of the tube.

Another object of my invention is to provide a new and improved snubber structure which, in addition to insuring satisfactory transverse fit in a tube envelope, is adapted to assist in minimizing longitudinal movement of the tube mount and thereby increase rigidity of the mount in the tube envelope.

Still another object of my invention is to provide new fitates Patent die;

and improved integrally formed snubbers and iusulative mount support thereby to take advantage of the cost reductions available through this practice.

Purher objects and advantages of my invention will become apparent as the following description proceeds and the features of novelty which characterize my *2 w"l be pointed out with particularity in the iexed to and forming part of this specification.

in carrying out the objects of my invention, l have provided an insulative member including a plurality of outwardly extending fingers of sufiicient length to insure bending thereof rather than breakage upon insertion into a tube envelope. The fingers may be of different lengths to compensate for variations in bulb sizes and configurations and to adapt the supports for use in a wide range of bulb sizes. The fingers may extend at oblique angles thereby to provide for maximum finger length with minimum consumption of the body portion of the member.

For a better un-Cerstanding of my invention, reference may be had to the drawing in which:

Fig. 1 is a partially sectionalized view illustrating a step in the assembly of device in which my invention may be incorporated;

Fig. 2 is a partially broken away view of a tube incorporating my invention;

Fig. 3 is a sectional view taken along the line of Fig. 2 showing an insulative support formed in accordance with one embodiment of my invention;

Fig. 4 is a sectional view taken along the line i---t in Pig. 3 and looking in the direction of the arrows;

Fig. 5 is a plan view of a modified form of my invention;

Pig. 6 is a fragmentary sectional view taken along the line 66 in Fig. 5 and looking in the direction of the arrows;

Fig. 7 is a plan view of a further modified form of my invention;

Fig. 8 is an enlarged fragmentary plan view of an insulative support constructed in accordance with a still further embodiment of my invention; and

Fig. 9 is an enlarged fragmentary plan view of an insulative support constructed in accordance with still another embodiment of my invention.

Referring to Fig. l, l have illustrated the manner in which, during the usual assembly of an electronic tube, a tube mount l is positioned for insertion into a sub stantially cylindrical bottle or bulb L The mount 1 comprises a plurality of electrodes generally designated 3 and mounted between a spaced pair of insulative supports or spacers 4 as by having end portions extend through suitabie apertures in the supports. The mount is supported atop an insulative stem E by having portions of the electrodes suitably connected to portions of leads 6 which extend in a sealed manner through the stem 5.

Heretofore, it has been the practice to construct or form the insulative spacers d of mica and to include small integral pointed tips or snubbers which engaged the inner wall of the envelope 2 when the mount was inserted into the bulb. These tips were intended to insure a tight fit of the supports in the bulb thereby to provide for rigidity of the mount and to reduce tube noise. However, it was found that often the walls of the bulb were not straight as intended with the result that the lower or open end of the bulb was sometimes out of round or smaller in diameter than the major portion, in the manner indicated by the dot and dash lines designated 2 in Fig. 1. As a result when the mount was inserted or passed into the bulb the small pointed snubbers had a tendency readily to crush and break off, causing a loose fit of the supports in the bulb and the presence of undesirable loose particles in the envelope. Also where the pointed snubbers did not entirely break off, a marked tendency was observed for one or more of the laminations of which the pointed snubbers were constituted to break off, thereby introducing bits of support material into the bulb and rendering the remaining portion of the pointed snubbers more likely to break oil. in response to continued vibration of the tube. Furthermore, such pointed snubbers, weakened by the fracture of one or more laminaticns failed eificiently to perform the function of rigidly supporting the mount.

As seen in Figs. 2 and 3, my invention contemplates the provision of insulative supports or disks 4 which are formed to include a plurality of elongated radially extending circumferentially spaced fingers 1d which are of sufficient radial length to insure flexibility or bending thereof without breakage or crushing of individual fingers or of individual lamina of which the fingers are constituted during insertion of the mount into the bulb 2. This desired flexibility can be obtained by forming the supports 4 of mica or similar insulative material having a thickness in the range of .005 to .020 of an inch and by dimensioning the fingers 16 so that the radial lengths thereof are greater than the width at the root or innermost portion of the fingers.

I have found that when so proportioned the bending moment, to which such fingers are exposed during the insertion of the mount in a non-concentric bulb, is insufficient to cause fracture either of the fingers as a whole or of individual laminations of which the fingers are constituted. Accordingly, the undesired features of the prior art constructions residing in the looseness of fit, the introduction of loose elements in the bulb, and the production of weakened snubbers are largely obviated.

Additionally, the fingers 10 are of such length that the outermost ends or tips thereof define a circle or area just slightly greater than the normal internal diameter or cross-sectional area, respectively, of the bulb 2. As a result, resilient bent engagement of the fingers with the walls of the bulb, in the manner shown in Figs. 2, 3 and 4, is insured.

According to a modification of my invention and as shown in Fig. 5, the supports 4 may be formed to include a plurality of radially extending circumferentially spaced secondary fingers 11 in addition to the fingers 1d of the above-described embodiment. These fingers may also be formed so as to be greater in radial length than in width at the roots thereof; and thus, like the fingers 10 are rendered more flexible, and thus minimize the tendency to fracture. The fingers 11 which, as shown are of relatively shorter radial dimension than fingers 10, are preferably each interposed between a pair of the fingers It? in the manner illustrated, and the outermost portions or tips thereof may define a circle or area substantially the same as the normal inner diameter or cross-sectional internal area, respectively, or the bulb 2.

As seen in Figs. 5 and 6 the longer fingers 1t bend or flex in the manner illustrated but do not crush or break nor do any of the individual lamina flake off. The degree of bending of each of the fingers 14B depends on the trueness of the engaged portions of the bulb walls to the desired cross sectional shape of the bulb 2. Additionally, the shorter fingers 11 tend to engage the inner wall of the bulb or envelope without bending in the manner shown in Fig. 6. However, in the event that the bulb is out of round some of the fingers 11 may also bend in a manner similar to the fingers 10.

As also seen in Fig. 6 and as a result of the difference in lengths, the fingers li and 11 tend to engage the inner wall of the bulb 2 at different levels. This results in improved resistance to longitudinal movement of the mica support in the envelope, which in turn provides for increased rigidity of the mount 1.

It will be understood that my invention is equally applicable to composite insulative supports. For example, and

as shown in Fig. 7, my invention may comprise an annular member 12, or a member of any other configuration which provides a central opening, and an insulative strip 13 secured across the opening and adapted for receiving and supporting electrode elements. The composite electrode mount structure including the annular member 12 and strip 13 is not my invention but is disclosed and claimed in co-pending U. S. application Serial No. 504,957, I. F. Stephens, filed April 29, 1955, and assigned to the same assignee as the present invention. The mem- 12 may be formed of the same material and to the same thickness as the above-described support 4. Additionally, the member 12 may be formed to include fingers identical to the fingers 19 and 77 and, accrdingly, having the same numerical designation.

In Fig. 8 is illustrated another embodiment of my sup port generally designated 15. In this embodiment also the support may be formed of mica in the range of thicknesses from .005 to .020 of an inch. Additionally, the support 15 is formed to include a plurality of elongated radially extending flexible fingers 16 of substantially parallel sides and which are spaced circumferentially about the support at somewhat less spacing between adjacent fingers than the elongated fingers of the abovedescribed embodiments. However, like the fingers of the described embodiments, the fingers 16, in order to provide the desired flexibility and resistance to fracture, are greater in length than in width at the root thereof or where the fingers are attached to the 'body portion of the support. Additionally, the outermost portions or ends of the fingers 16 define an area slightly greater than the normal inside cross-sectional area of the bulb 2. If the bulb is cylindrical the ends of the fingers 16 will define a circle slightly greater in diameter than the normal inside diameter of the bulb.

Formed between the elongated fingers 16 are shorter parallel side fingers 17 which are also greater in length than in Width and which define an area or a circle substantially the same as that defined by the normal inner wall of the bulb 2. The support 15 is adapted for fitting in the bulb 2 in substantially the same manner as the support 4 described above; however, the increased number of fingers are adapted for insuring a tighter fit in the bulb and increasing the rigidity of the mount 1.

In Fig. 9 is illustrated a third embodiment of my invention generally designated Ztl. The support 20 may be formed of the same material and thickness as the abovedescribed embodiments and includes a plurality of elongated flexible fingers 21 corresponding generally to the fingers 16 and a plurality of alternately disposed shorter fingers 22 corresponding generally to the fingers 17 in Fig. 8. Like the fingers of the first and second embodiments, the fingers 21 and 22 each are longer or greater in length than in width at the roots or portions at which they attach to the body of the support Zfi. Additionally, fingers 21 and 22 all extend obliquely or at acute angles to the radii of the support 20. This permits the fingers to be formed of greater length, and consequently provide greater flexibility and resistance to fracture, while consuming a minimum amount of the body portion of the support 2t Additionally, the outermost'points or portions of the fingers 21 define a circle slightly greater in diameter than the normal inner diameter of the bulb 2 and the outermost tips or portions of the fingers 2.2. define a circle substantially equal in diameter to the normal inner diameter of the bulb 2. If the bulb is other than cylindrical the support 2i can be formed so that the tips of the fingers 21 and 22 will define areas slightly greater and the same as, respectively, the inner cross-sectional area of the bulb. The support 29 is adapted for being used in substantially the same manner as described above with regard to the first embodiment.

Thus, it will be seen that I have provided a new and .improved insulative support which is adapted for insuring a tight fit of a tube mount in an envelope regardless of substantial variations or irregularities in the envelope configuration thereby to insure lateral rigidity of the mount and to minimize noise during tube operation. Additionally, my structure insures against breakage of any portions of the support during assembly, shipping and use and thereby prevents the presence of undesirable loose pan ticles of the support material in the tube. Still further, my support is adapted to provide increased longitudinal rigidity of the mount in the tube.

While I have shown and described specific embodiments of my invention, 1 do not desire my invention be limited to the particular forms shown and described and I intend by the appended claims to cover all modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Fatent of the United States is:

1. l/ieans for supporting a structure in an envelope having an axis, comprising an insulative planar disk-like mem er adapted for being positioned transversely in said envelope, said member including a plurality of projections integral with and extending from the outer edge thereof, said projections being greater in length than in width at the bases thereof and thereby adapted for bending engagement with said envelope without fracture of said projections when said member is positioned in said envelope.

2. Means for supporting a structure in an envelope comprising an iusulative member adapted for being positioned transversely in said envelope, said member including a plurality of outwardly extending circumferentially spaced fingers formed off the periphery thereof, said fingers defining an area slightly greater than the cross-sectional internal area of said envelope, said fingers being greater in length than in Width at the innermost portions thereof and thereby adapted for bending and avoiding breakage thereof when said member is positioned in said envelope.

3. Means for supporting electrode elements in insulated spaced relation in an envelope comprising a mica member adapted for being positioned transversely in said envelope and having a thickness in the range of from .005 to .020 of an inch, said member including a plurality of outwardly extending circumferentially spaced fingers formed oil? the peripheral edge of said member defining an area slightly greater than the cross-sectional internal area of said envelope, said fingers being greater in length. than in width at the root portions thereof and thereby adapted for bending and avoiding breakage of said fingers or individual lamina constituting said fingers when said member is positioned in said envelope.

4. Means for supporting a structure in an envelope comprising an insula ve member adapted for being posi tioned transversely in said envelope, said member including a first plurality of outwardly extending circumferentially spaced fingers defining an area slightly greater than the cross-sectional internal area of said envelope, and a second plurality of circurnierentially spaced fingers interposed between the fingers comprising said first plurality and defining an area substantially the same as the cross-sectional internal area of said envelope, said fingers being greater in length than in width at the root portions thereof and thereby adapted for bending and avoiding breakage when said member is positioned in said euvelope.

5. Means for supporting electrode elements in insulated spaced relation in an envelope comprising a mica member adapted for being positioned transversely in. said envelope and having a thickness in the range of from .005 to .020 of an inch, said member including a first plurality of outwardly extending circumferentially spaced fingers formed off said member and defining an area slightly greater than the cross-sectional internal area of said envelope, and a second plurality of outwardly extending circumferentially spaced fingers interposed between the fingers comprising :1 first morality and defining an area substantially the same as the cross-sectional internal area of said envelope, said fingers being greater in length than in width at the innermost portions thereof and thereby adapted for bendi g and avoiding breakage of said fingers or individual u'na constituting said fingers when said member is posi tioned in said envelope.

6. Means for supporting a structure in an envelope comprising a member adapted for being positioned transversely in said envelope, said member including a plurality of outwardly and obliquely extending circumferentially spaced fingers, the outermost portions of said fingers defining an area slightly greater than the cross-sec tional area of said envelope, said fingers being greater in length than in width and thereby adapted for bending and avoiding breakage when said member is positioned in said envelope.

7. Means for supporting electrode elements in insulated spaced relation in an envelope comprising a mica member adapted for being positioned transversely in said envelope and having a thickness in the range of from .005

to .020 of an inch, said member including a plurality of outwardly obliquely extending circumferentially spaced fingers, the outermost portions of said fingers defining an area slightly greater than the cross-sectional internal area of said envelope, said fingers being greater in length than in width at the base thereof and thereby adapted for bending and avoiding breakage of said fingers or individual lamina constituting said fingers when said member is positioned in said envelope.

8. Means for supporting a structure in an envelope comprising a member adapted for being positioned transversely in said envelope, said member including a first plurality of outwardly and obliquely extending circumferentially spaced fingers, the outermost portions of said fingers defining an area slightly greater than the cross-sectional internal area of said envelope, and a second plurality of outwardly and obliquely extending circumferentially spaced fingers, the outermost edges of said last-mentioned fingers defining an area substantially the same as the cross-sectional internal area of said envelope, said fingers being greater in length than in width at the innermost portions thereof and thereby adapted for bending and avoiding breakage when said member is positioned in said envelope.

References Cited in the file of this patent UNITED STATES PATENTS 1,974,086 Smith Sept. 18, 1934 1,982,069 Reed Nov. 27, 1934 2,078,371 Daene Apr. 27, 1937 2,527,166 Walsh Oct. 24, 1950

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