US2641728A

US2641728A - Heater connector

Info

Publication number: US2641728A
Application number: US146332A
Authority: US
Inventors: Bayard R Corson; A V Platter
Original assignee: International Business Machines Corp
Current assignee: International Business Machines Corp
Priority date: 1950-02-25
Filing date: 1950-02-25
Publication date: 1953-06-09
Anticipated expiration: 1970-06-09

Description

J1me 1953 B. R. coRsoN ETAL 2,641,728

HEATER CONNECTOR Filed Feb. 25, 1950 INVENTORS 50mm A. (UliJO/V 14. V. PLAT/TR Patented June 9, 1953 HEATER CONNECTOR Bayard R. Col-son, Fishkill, and A. V'. Platter, Poughkeepsie, N. Y., assignors to International Business Machines Corporation, New York, N. Y., a corporation of New York Application February 25, 1950, Serial No. 146,332

3 Claims.

This invention relates to vacuum tubes havin indirectly heated cathodes and more particularly to a novel heater connector for use with a single-helix type heater in such tubes.

The helix type heater must be electrically connected at each end to permit electrical current to pass through it. The temperature of the heater coil itself when passing current is very large as compared to its normal room temperature when not passing current. As a result tremendous expansion and contraction of the coil, as the case may be, takes place after the change from the operating or non-operating condition. In addition to the helix type heater the invention is particularly applicable to the folded type heater having an odd number of legs and the ceramic rod type heater.

. In the prior art the connection of each end of a heater coil to a rigid member which does not expand and contract with the coil as it expands and contracts has caused the tube to have a relatively short operating life because of the mechanical fracture of the heater coil.

It is a principle object of the invention to provide a novel heater connector for a helical type heater coil wherein tube failure because of mechanical fracture of the heater coil is substantially eliminated.

Another object is to provide a novel heater connector wherein expansion and contraction of the heater coil due to the heating and cooling thereof respectively, is caused to occur in a predetermined direction such that the heater coil always remains substantially the same distance from the cathode in a transverse direction and the uniform heating of the cathode is substantially unaffected.

A further object of the invention is to provide a novel heater connector for a spiral type heater wherein expansion and contraction of the heater is permitted only longitudinally thereto.

A still further object is to provide a heater connector which permits virtually free expansion of the heater in one direction, protects the heater from shocks in all other directions, and is cheaply made with automatic machinery.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of examples, the principle of the invention and the best mode, which has been.

contemplated, of applying that principle.

In the drawings:

Fig. 1 shows a vacuum tube structure em- 5 bodying the invention,

Fig. 1a is an enlarged isometric View of the invention shown in Fig. 1, and

Fig. 2 shows diagrammatically the application of the invention to a tube employing two heater elements.

Briefly, the invention includes the connection of a spiral type heater in the usual rigid man-. ner at one end and the connection of the other end of the heater to a conductive member arranged in longitudinal alignment with the heater coil. A ribbon shaped connector is bent at each end to form a right angle. One bent portion is welded to the conductive member so that the plane formed by the face of the ribbon connector is substantially parallel with the plane of the transverse axes of the conductive member. The other bent portion of the ribbon connector is rigidly aflixed to another conductive member in the heater circuit. The connector offers a Very high resistance to the transverse movement of the heater and a minimum resistance to its longitudinal movement. As a result, when the heater expands and contracts due to heating and cooling it remains substantially the same distance in a transverse direction from the other tube elements. This structure eliminates the possibility of non-uniform electron emission from the cathode due to the non-uniform heating thereof and insures long tube life because of the decrease in the mechanical fracture of the heater itself.

Referring more particularly to Fig. 1, the tube is the conventional cylindrical cathode type and is mounted on a base In having a plurality of conductive pins extending therethrough. The electrodes of the tube are mounted between the spacers II and I2. Cylindrical cathode I3 is supported between the spacers II and [2 in any conventional manner. The grid l6 and plate I! are positioned outward from and concentric with cathode 13. The spiral heater I9 is supported within the cathode l3 by a conductive support '20 connected to pin 2|. The heater I9 is rigidly connected to support 20 in any conventional manner so that electrical current is passed thereto through the pin 2 I.

The upper end of the spiral heater :9 is connected to a conductive support 22 arranged in longitudinal alignment with the heater IS. The support 22 is connected at its upper end (not shown), in any conventional manner to permit it to expand and contract longitudinally as it successively heats and cools. The conductive member 24 extending through and fastened to the spacers II and I2 is substantially parallel to 5 the heater l9 and. support 22. The lower end of member 24 is connected through support 26 to the pin 28.

A conductive ribbonrshaped heater connector 30 is bent at each end to form substantially a right angle. One end of the connector is welded to the support 22 and the other end to the member 24. This connection completes the heater circuit.

The function of the connector may be more clearly appreciated from Fig. 1a. It should be particularly noted that the face of the ribbon shaped connector as is in a plane substantially parallel to the transverse axis of the support 22 and the heater i9. Hence, because of the geometric configuration the connector 38 ofiers high resistance to the movement of support 22 in any transverse direction and offers a minimum resistance to the movement of the support in a longitudinal direction. As a result, the expansion and contraction of the heater is and support 22 due to the operation and non-operation of the tube is up and down respectively or is longitudinal. Repeated expansions and contractions of the heater therefore permit it to remain everywhere the same distance in a transverse direction from the cathode. This eliminates nonuniform electron emission from the cathode due to non-uniform heating. This movement also lessens overworking of the heater or mechanical fracture thereof. It has been found that the invention provides a tube having a much longer life free of heater failures than tubes of the prior art.

The particular dimensions of the various elements employed will, of course, vary in accordance with each particular tube designed. It suffices to state that the geometry of the heater [9, support 22 and connector 39 are such that the connector permits relatively easy longitudinal movement of the heater and support.

Fig. 2 demonstrates diagrammatically one way of using the invention in a tube employing two heater elements. The tube contains a support means such as the horizontal bar, 35 welded to the vertical supports 3% and 31. The

members

38 and 39 are the respective heater elements of the tube or members which expand and contract with the respective heaters. The ribbon shaped connector at is U-shaped at either end to fit over the respective heaters and is rigidly afiixed thereto. A center portion of the ribbon connector is welded to the bar 35 as shown, each portion of the connector extending from the bar to its respective heater and being responsive to the longitudinal expansion and contraction of that heater independently of the other portion of the connector.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a vacuum tube having a spiral heater element fixedly connected at one end; a first conductive member connected to the other end of said element and extending longitudinally therefrom; a ribbon shaped connector affixed at one end to said first member and extending substantially perpendicularly therefrom and rigidly affixed at its other end, the two faces of said ribbon shaped connector being in planes substantially coincidental with a plane formed by the transverse axis of said first member so that the expansion and contraction of said element caused I by the heating and cooling thereof is substantially longitudinal with said first member because said ribbon shaped connector, due to its shape, offers the least resistance to the longitudinal movement of said first member.

2. In a vacuum tube having a cathode and a heater element mounted in spaced relation thereto. a conductive member connected to one end of said element and expandable therewith, a ribbon shaped connector rigidly fastened at one end and welded to said member at its other end so that said connector ofiers less resistance to the movement of said member along a preselected single path than along any other path whereby said member remains in substantially the same spaced relation to said cathode irrespective of the expansion and contraction of said element.

3. In a vacuum tube having a heater element rigidly connected at one end, a cylindrical cathode mounted in spaced relation around said heater element, a first conductive member arranged substantially parallel to said heater element and aifixed at one end, a ribbon shaped connector affixed at one end to said first conductive member and at the other end to the other end of said heater element whereby said connector because of its ribbon shape offers less resistance to the movement of said heater element inone direction than in any other direction to ensure that said heater will move only in said one direction as a result of the expansionand contraction thereof BAYARD R. CORSON. A. V. PLATTER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,936,069 Reid Nov. 21, 1933 2,016,152 Marden et al Oct. 1, 1935 2,339,402 I-Ierzog Jan. 18, 1944-.