US2871621A

US2871621A - Beading fixture

Info

Publication number: US2871621A
Application number: US616510A
Authority: US
Inventors: Eugene O Hanson; James L Shrontz
Original assignee: RCA Corp
Current assignee: RCA Corp
Priority date: 1956-10-17
Filing date: 1956-10-17
Publication date: 1959-02-03
Anticipated expiration: 1976-02-03

Description

Fell 3, 1959 E. o. HANsoN ET AL 2,871,621

BEADING FIXTURE Filed oct. 1v, 195e INVENTORS JAMES I.. Sx-mnmz EUEENE D. HANSEN READING FIXTURE Eugene 0. Hanson, Marion, and .lames L. Shronta, Gas City, Ind., assgnors to Radio Corporation of America, a corporation of Delaware Application October 17, 1956, Serial No. 616,510

6 Claims. (Cl. 491) This invention is directed to a beading fixture for holding together a plurality of electrode elements while they are being assembled into a rigid assembly.

The electrodes used to form an electron gun for a Vcathode ray tube are normally assembled together in a rigid mount structure, which is then sealed into the vcathode ray tube envelope. A technique used is a glass beading operation, which utilizes metal studs or straps welded to the several electrodes in a manner such that a plurality of the studs or straps lie in a common plane when the electrodes are arranged in the desired relationship. A glass rod is softened by heat and is pressed onto those studs aligned in the common plane. The glass of the rod, upon hardening around the metal studs, grips them tightly to hold the electrodes in their pre-arranged positions. at different positions to rigidly hold the electrode structures together.

During this operation of glass beading or of joining the electrodes together into a mount structure, the electrodes themselves are held in a fixed relationship spaced from each other, by a fixture or jig, which relationship is desired in the final electrode assembly. Spacing elements or spacers are disposed between the electrodes to hold them in the desired spaced relationship during the beading operation. The spacing elements are movably mounted on the fixture, so that, as the electrodes are fixed into the fixture, the spacer elements can be movably positioned between the electrodes. After the glass beads have been attached, as set forth above, the assembled electrodes, now constituting a gun mount, are removed from the fixture. It has been found that at this point the spacer elements, which are retained in the fixture, tend to bind with the electrodes in contact with them, so that upon removal o f the assembled electrode structure from the fixture, the electrodes may become bent or misaligned with each other with the result that the assembled electrode structure is discarded as being inoperative.

Therefore, it is an object of this invention to provide a novel structure, which can be used in beading electrode parts together without also providing a distortion or misalignment of the electrode parts.

It is another object of this invention to provide a jigging fixture structure having spacing elements attached thereto, which can be used in the assembly of a plurality of electrodes without also providing distortion and misalgnment of electrode parts.

The invention is that of a jigging fixture used specifi cally in the assembling of a plurality of electrodes into a gun mount assembly for use in a cathode ray tube. The fixture has a plurality of spacing elements attached thereto for holding the electrode parts in the spaced relationship desired in the final gun construction. The spacing elements are mounted on a movable portion of the fixture so that they can be removed from the assembled electrode mount structure before it is removed from the Normally a plurality of glass rods are used nited States )amm Patented Feb. 3, 1959 2 fixture. This obviates the distortion and misalignment of electrode elements which often accompany the use of prior fixture structures.

Figure l is a longitudinal view partially in section of the novel fixture in accordance with this invention;

Figure 2 is a three-dimensional view of an electron gun assembly of the general type assembled by the fixture of Figure l;

Figure 3 is a cross sectional view of the fixture of Figure l and along the section lines 3 3.

The structure shown in Figure l is used for holding a plurality of electrode elements in a predetermined spaced relationship, while they are being joined into a rigid assembled structure. Such an assembly of electrode elements is shown in Figure 2, which by way of example shows a sub-assembly 10 of an electron gun mount for a television picture tube. This invention is described relative to a fixture for assembling such an electron gun structure, by way of example only. It is obvious, however, that the novel fixture structure to be described may be utilized in principal for joining other elements into assembled units.

The electron gun assembly 10 of Figure 2, consists of a cylindrical control grid 12, a cup shaped electrode 14 having non-parallel ends, as shown in Figure 2, and a bent tubular electrode consisting of two portions 16 and 18 whose axes are at a slight angle to each other. A cylindrical focusing electrode 2l) is mounted in a telescoped arrangement over the free end of tubular electrode portion 18. Figure 2 shows the electron gun elements as assembled into a mount assembly. To rigidly hold these gun electrodes with their predetermined spacings and position, each electrode is provided with a plurality of small metal studs 22 welded to the outer wall portions of each electrode respectively. in Figure 2, the studs are shown as welded from substantially diametrically opposite sides of each electrode and so that all of the studs 22 on one side of the electrodes will lie substantially in a common plane. This permits the joining of the electrodes to a pair of glass rods Z4, one on each side of the electrode assembly and which are fixed to the individual electrodes by first being softened by heat and then being pressed onto the studs 22 to form the unitary structure of Figure 2.

To hold the several electrode structures together while they are being joined, the beading fixture l1 of Figure l is used. The fixture consists of a lower body portion 26 and an upper body portion 2S, pivotally mounted at 29 to the lower body portion. Asvshown in Figures 1 and 3 when the upper body portion 28 is closed down onto the lower body portion 26 there is formed between them an accurate chamber 30 receiving the tubular electrode members similar to those of the assembly shown in Figure 2. Figure l shows corresponding electrodes 12', 14', 16', 18 and 20' mounted within the chamber 30 between the two body portions 26 and 2S of the beading fixture 11. Portions of the edges of the upper and lower body portions are removed so that when the lower and upper body portions are closed together there are formed lateral openings 32 extending from the chamber 3l) to the outside of the xture 11 as shown in Figure 3. These openings permit the studs 22 to extend outside the fixture in the positions shown in Figure 3, so that the glass beads may be mounted thereon. The openings 32 run generally longitudinally of the cavity 30.

The electrode parts to be assembled are loaded into the fixture 11, by first pivoting the upper body portion 28 upwardly in a clockwise direction, shown in Figure 1, so as to open the fixture and expose the interior cavity 30. The cylindrical electrode 20 is inserted against the spring-pressed end block 34 of the lower fixture body portion 26. Tubular electrode 18 is next positioned against the block face 36 of an extension of the stop block 34 of the lower fixture body. The tubular electrode 16 is loaded into contact with the free end of tubular electrode 18. Then a pivoted spacer plate 38 is positioned with one face against the free end of the electrode 16 and the cup shaped electrode i4 is fixed in its proper axial orientation against the other face of spacer plate 38. A second spacer plate is fixed with one face against the free end of electrode 14 and the control grid electrode 12 is positioned against the other face of spacer plate 4t?.

The several gun electrodes are positioned in this manner with their studs 22 extending respectively through both-openings 32 and in alignment on both sides of the xture 1l, as shown in Figures l and 3. The upper body portion 28 is then closed down onto the electrodes, positioned as described, and a springV pressed plunger i2 is released to contact the free end of electrode 12' and to press all of the assembled electrodes tightly together.

Plunger 42 is urged by a spring member 44, which is in turn, housed within the hollow opening do of an arbor 48.' The arbor is fixed for longitudinal movement in a housing rigidly mounted to the lower fixture body portion 26. At the free end of the arbor 43, a manually operable knob 52 is fastened for operating the beading xture. Fixed to the arbor 48 by a pin 54, is a slidable mounted latch 56 having a portion 58 adapted to extend over the upper body portion 2S to hold it in its closed position, during the beading of the electrode mount. A spring 60 between a stepped portion 49 of the arbor 48 and the end portion 51 of the housing 50 urges the arbor and its latch 56 toward the right. Thus, after the upper body portion 28 is closed relative to the lower body portion 26, arbor 48 is released and urged toward the right, into the position shown in Figure l. This motion of the arbor carries the latch portion 5S over the underlying portion of the upper body 23 to loch it in its closed position.

Movement of arbor 48 to the right brings the springpressed plunger 42 into contact with electrode 12 and as described above tightly presses together all of the assembled electrodes in cavity 30, so as to hold them in fixed position. The pin 54 extends through a slot 62 of the arbor housing S0. Slot 62 includes `a notched portion 64, at one end, so that when the latch 56 is withdrawn by manually pulling the arbor 48 to the left, and the arbor is turned about its axis, pin 5d will enter notched portion 64 and lock the arbor in its retracted position. With this arrangement, the operator, upon closing the body portions 26 and 2S together, after loading the cavity 30 with the several electrode elements, can, with a single operation, release the arbor 4S and permit it to be spring-,pressed into its operative position.

To bead the several electrode parts together, the glass beads 24 are heated by any appropriate manner such as by gas fiames (not shown) to a softened condition. The fixture ll is then positioned, by the operator, so that all of the studs 22'extending from one side of the electrode assembly through fixture openings 32 can be pressed into the glass rod simultaneously. The glass of the rod is allowed to harden around the studs for a few moments and then the aligned studs on the other sides of the fixture are pressed into a second glass rod 24. After a few moments of cooling, the glass has suiiiciently hardened about the studs. so that the operator can open the fixture and remove the beaded gun mount.

It has been found, however, that in removing the gun mount from the fixture, the spacer elements 3S and 46 will bind with the electrodes with which they are in contact, during the beading operation. Forcibly removing the gun mount from the xture will frequently cause damage to the electrodes themselves by bending or twisting them, and more frequently, the electrodes themselves become misaligned so that the electron lens forming apertures between the electrodes become misaligned. For example, the alignment of the adjacent apertures in electrodes 12 and 14 respectively is quite critical and should be maintained to within l mil for optimum operation of the electron gun. Misalignment of these electrode apertures, provides a non-symmetrical or distorted lens field between electrodes l2 and 142' so that during tube operation, the electron beam passing through this lens field becomes distorted and even deilected from its normal path.

in accordance with the invention, then, the spacers .Se and are mounted on pivot pins 66 and respectively, which in turn are fixed for movement in elongated slots 67 and 69 respectively, of ejector bnr 7G. The ejector bar itl is also pivotally mounted at '72 to the lower jig body portion 26. The bar 7@ has a manually operable handle 74. In accordance with the invention, before the latch portion 58 is opened, and, while the gun mount is still rmly iixedwith the cavity 3) of the fixture, the spacers 38 and di) are removed from the assembled gun mount. This is performed by the operator, who, with the aid of the handle 74, pivots the spacer ejecting bar 70 in a counter-clockwise direction, shown in Figure l. This withdraws the spacers 33 and t? from the assembled gun mount and allows the mount to be completely free of the spacers. Duringthe withdrawal of spacers 38 and 46, they have pivotal movement as well as ability to slide longitudinally along their respective slots 67 and 69. This permits the spacers to move out from between the respective electrodes without bending and without exerting any pressure on the electrodes. Then, the upper jig body 23 is opened and the gun mount removed without distorting or misaligning the electrode parts. The counter-clockwise movement of the ejector `bar 7@ is limited by a stop pin 76-striking a surface 7S of the lower body portion 26.

What is claimed is:

l. A beading fixture for maintaining electrode elements in a spaced relationship while beingV joined into a rigid assembly, said fixture comprising a body portion having a longitudinal cavity therein and means including a spring pressed plunger mounted within said body cavity for maintaining said electrode elements in fixed relationship, a spacer element pivotally mounted within said cavity for spacing a pair of electrode elements during assembly, and means for removing said spacer element from .said body cavity while said electrode elements remain within said cavity.

y 2. A beading fixture for maintaining electrode elements in a spaced relationship while being joined into a rigid assembly, said fixture comprising a body portion having a longitudinal cavity therein and means for supporting said electrode parts and maintaining them in fixed relationship, a plurality of spacer elements pivotally mounted within said body cavity for spacing a plurality of electrode elements during assembly, and an ejector bar mounted on said body portion for removing said spacer elements from said body cavity.

3. A beading fixture for maintaining electrode elements in a spaced relationship while being joined into a rigid assembly, said fixture comprising a pair of body portions removably fitted together to form a cavity therebetween, said body portions including means for supporting said electrode elements within said cavity in a fixed spaced relationship, a spacer element pivotally mounted within said cavity for spacing a pair of said electrode elements, and means mounted on one of said body portions for removing said spacer element without separating said body portions.

4. A beading xture for maintaining electrode elements in a spaced relationship while being joined into a rigid assembly, said fixture comprising a pair of body portions removably fitted together to form a cavity therebetween, said body portions including means for supporting said electrode elements within said cavity in a xed spaced relationship, a spacer element pivotally mounted within said cavity for spacing a pair of said electrode elements, and a pivoted ejector bar mounted on one of said body portions for removing said spacer element without separating said body portions.

5. A beading fixture for maintaining electrode elements in a spaced relationship While being joined into a rigid assembly, said fixture comprising a body portion having a longitudinal cavity therein and mains for supporting said electrode parts and maintaining them in fixed relationship, a plurality of spacer elements pivotally mounted within said body cavity for spacing a plurality of electrode elements during assembly, and an ejector bar mounted on said body portion for removing said spacer elements from said body cavity, said spacer elements being pivotally mounted on said ejector bar.

6. A beading xture for maintaining electrode elements in a spaced relationship while being joined into a rigid assembly, said xture comprising a body portion having a longitudinal cavity therein and means for supporting said electrode parts and maintaining them in fixed relationship, said means including a plurality of spacer elements pivotally mounted within said body cavity for spacing a plurality of electrode elements during assembly, an ejector bar mounted on said body portion for removing said spacer elements from said body cavity, said ejector bar having slots therein, and means fixing one end of each spacer element for longitudinal and pivotal movement in a diiferent one of said slots.

References Cited in the file of this patent UNITED STATES PATENTS 1,045,911 Thomson Dec. 3, 1912 1,445,231 Muller Feb. 13, 1923 2,174,853 Bowie Oct. 3, 1939 2,553,749 Clark et al May 22, 1951 2,600,076 Schelling June 10, 1952 2,707,848 Pityo May 10, 1955