US2790117A - Multiple-gun cathode-ray tube beam magnet assembly - Google Patents

Description

R. A. MAHER April 23, 1957 MULTIPLE-GUN CATHODE-RAY TUBE BEAM MAGNET ASSEMBLY Filed Sept. 1. 1955 mvmroz; RICHARD A. MA HER. -azdm QW ATTORNEY3.

MULTIPLE-GUN CATHODE-RAY TUBE BEAM 1 MAGNET ASSEMBLY Richard A. Maher, Cincinnati, Ohio, assignor to Avco Manufacturing Corporation, Cincinnati, Ohio, a corporation of Delaware Application September 1, 1953, Serial No. 377,935 2 Claims. or. 317-200 This invention relates generally to cathode-ray tube deflecting means and more specifically to a means which provides a fixed field, adjustable in space, for use in deflecting and positioning individual electron beams in a multiple-gun cathode-ray tube.

With the advent of color television and the use of cathode-ray tubes having a multiple-gun structure, it became necessary to provide structures for adjusting the spatial position of the individual electron beams relative to the remaining beams emanating from the multiplegun unit. The bending effect of a permanent magnet field on the electron beam being well known, it became conventional to position magnets around the neck of the tube.

These prior art adjustable magnet mount structures were fixedly attached to the receiver chassis and arranged to allow positioning of the various magnets relative to the electron beam desired to be brought under control. Though these devices have proved to be relatively satisfactory in laboratory units where the etfect of a shift between the cathode-ray tube and the receiver chassis can be readily corrected, it would be desirable to provide a magnet assembly fixedly mounted on the cathode-ray tube so that movement of the cathode-ray tube relative to the receiver chassis cannot change the magnetic force exerted by each magnet on the electron beams.

Further, it would be desirable to provide magnet mounts which were easily adjustable and also capable of being locked or rigidly fixed in position. Thus, it is an object of this invention to provide a beam positioning magnet mount which is fixedly attached to the neck of the cathode-ray tube.

It is also an object of this invention to provide a magnet mount having a wide range of magnet positioning adjustments.

It is a further object of this invention to provide a magnet positioning assembly which, though easily adjustable, can be locked or secured in a selected position.

Briefly, my invention comprises a magnet mount fabricated from non-magnetic material and provided with a plurality of flange portions, each of which is arranged to hold an adjustable magnet positioning assembly. Each adjustable magnet positioning assembly comprises a stud threaded on the outside surface to receive a knurled nut which, together with the stud, forms a socket into which a centrally threaded ball member is positioned. A rubber or fiber washer is used to introduce variable frictional contact between the knurled nut and the ball supporting stud in order that the ball may be rotated in its socket without loosening the knurled nut. A magnet rod is threaded on one end to fit into the threaded opening in the ball member and is also threaded at the opposite end to receive and support a magnet-carrying block or similar holding device. Each magnet-carrying block carries a small permanent magnet having sutficient strength to influence the electron beams desired to be controlled.

For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the accompanying drawings in which:

Fig. 1 is a drawing showing an assembly of a specific embodiment of my invention; and

Fig. 2 is a cross-section of the ball and socket magnet 1 arm adjusting assembly.

In Fig. 1, I have shown a non-magnetic mounting ring 11 having outwardly extending flange supporting portions 12, each of which is integrally connected to a flange element 13. Each flange 13 supports a magnet positioning .assembly 14 having a stud 15 threaded on its outside surface to receive internally threaded knurled nut 16. Stud 15, as best shown in Fig. 2, may be attached to flange 13 by spinning, welding or any other method resulting in an integral connection.

Ball member 17 is positioned between knurled nut 16 and the upper surface of stud 15 which may be either recessed to receive the lower surface of ball 17 or, as shown in Fig. 2, drilled to provide a relatively small contacting shoulder. j

'A washer 9 fabricated from plastic, rubber, fiber, or some other similarly resilient material is provided for stud 15. This washer must have suflicient thickness to engage the lower surface of knurled nut 16 before the nut is advanced on the stud suiiiciently to lock ball 17 in the resulting socket.

Each magnet rod 18 is integrally connected to a ball 17 in conventional manner, such as in Fig. 2, where ball 17 is shown internally threaded to receive the threaded lower end of the magnet rod. It will be apparent that this structure allows magnet rod 18 to be moved into any angular position by loosening nut 16 until ball 17 is free to turn in the socket formed by stud 15 and the under portion of knurled nut 16 within the limits imposed by the shoulder on knurled nut 16. Washer 9 holds knurled nut 16 in position relative to stud 15. After rod 18 has been brought into the desired angular position, knurled nut 16 may be tightened so as to frictionally lock ball 17 between the upper shoulder on stud 15 and the portion of knurled nut 16 hearing against the upper surface of ball 17.

Each magnet rod 18 is threaded to receive an internally threaded magnet block 22 which carries a cylindrical magnet 21 having sufiicient field strength to act on a magnetic beam directed through ring 11. Since each magnet21 is positioned along one of the sides of its carrying block, and since the threaded opening in the magnet block is in spaced relationship with the position of the magnet, rotation of the magnet block around the longitudinal axis of the magnet rod results in movement of the particular magnet in question along an eccentric path.

Except for magnets 21, the complete structure is fabricated from non-magnetic material. Non-conducting bolt 30, which may be plastic, is used to close magnet supporting ring 11 in order to make certain that the ring does not form a large energy-consuming shorted turn around the longitudinal axes of the electron beams being controlled. In other words, the gap left in the ring by bolt 3 0 keflps eddy currents from circulating completely around ring This magnet assembly has the advantage over the prior art of being readily adjustable along the longitudinal axis of the cathode-ray tube neck and of being immune to vibratory movements of the cathode-ray tube relative to the receiver chassis. In addition, each magnet is adjustable through a wide range of positions, and the magnets 3 may be locked or secured in any position by tightening knurled nut 16.

Further, magnet blocks 22, which may be fabricated from suitable plastic or fiber, provide a wide range of positions available on the magnet supporting rod for fine adjustments after the rod is locked into place.

While there has been shown and described what is at present considered the preferred embodiment of the present inventiomit will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention as defined by the appended claims.

Having thus described my invention, I clairn:

l. A permanent magnet mount assembly for aesthetic: ray tube comprisinga generally circular mounting ring,

symmetrically'spaced outwardly extending flange portionsfixedly attached tovsaid ring, a permanent magnet for each flange, a-separate support block for each magnet, formed to hold the magnet and to provide a threaded aperture in spaced" relationship with and normal to the supported magnet, a'support rod for each block threaded to support the associated block so as to allow rotation of the block around and along the longitudinal axis of the rod, each magnet being so mounted as to be offset from the associated support rod, and a ball and socket joint for fixing saidrod with respect to said mounting ring and providing articulation between each of said flanges and the associatedmagnet-supporting rod, the ball'being se; cured to the end of the rod remote from the block and the socket being secured to the flange, all of the above memhere beingofnon-magnetic material excepting the permanent magnets.

2. A permanent magnet mount assembly for a cathoderay tube comprising the combination of a generally circular mounting ring formed to provide a plurality of symmetrically spaced outwardly extending flange portions,

one for each magnet to be supported, a threaded stud secured on and extending normally to each flange, a

knurled nut shaped to form a socket with each stud,

associated magnet support rod, each magnet being so' mounted as to be laterally displaced from its associated support rod, all elements of said combination other than the permanent magnets being of non-magnetic material.

References Cited in the file of this patent UNITED STATES PATENTS Kabuss Apr. 1, 1952 Ingle June V2, 1953

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