US3034778A - Article positioning device - Google Patents

Description

May 15, 1962 P. c. SHAFFER ET AL 3,034,778

ARTICLE POSITIONING DEVICE Zia/CM ATTORNEY May 15, 1962 p, c, sHAFFER ET AL 3,034,778

ARTICLE POSITIONING DEVICE Filed March 28, 1960 4 Sheets-Sheet 2 35 m1 1 II N 1II|IMmuyumnuum May 15, 1962 P. c. SHAFFER ET AL 3,034,778

ARTICLE POSITIONING DEVICE Filed March 28, 1960 4 Sheets-Sheet 3 INVENT R5 Paul CJ/mff'er; Kemefli f/affan 6' Y Lou/s f. Z/dar ATTOIRNEY May 15, 1962 P. c. SHAFFER E AL 3,034,773

ARTICLE POSITIONING DEVICE 4 Sheets-Sheet 4 Filed March 28, 1960 lllll a W/v INVENTORS Pau/ C5/iaF/6I; Ken 5 Sfraffan & BY Mu Z/bar A'ITORNEY 3,34,778 Patented May 15, 162

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3,034,778 ARTiCLE PQMTlUNING DEVME Paul C. Shaffer, Seneca Falls, Kenneth E. Stratton, Waterloo, and Louis P. Zidar, deneca Falls, N.Y., assignors to Sylvania Electric Products Inc, a corporation of Delaware Filed Mar. 28, 1960, Ser. No. rznez 2 Claims. or. 269-142 This invention relates to article positioning devices and more particularly to a device for accurately locating and holding a cathode ray tube envelope or the like during manufacturing operations.

It is a requirement in the production of cathode ray tubes and similar devices that the electron beam forming electrodes and the tube envelope must be aligned accurately with one another before the electrode structure is secured to the envelope. The electrode structure or gun is mounted upon lead pins passing through a separate glass support which is subsequently sealed to the envelope. The envelope and gun must be accurately aligned so that the electron beam generated and shaped by the gun will be accurately directed toward the phosphor screen formed n the tube faceplate.

Generally, a cathode ray tube envelope may be described as a truncated cone having a faceplate across the larger end and a tubular neck affixed to the smaller end. The longitudinal axis of the neck is aligned with the longitudinal axis of the cone. The faceplate, upon which the phosphor screen is formed, is transverse to the longitudinal axis of the cone. Existence of the common longitudinal axis of the neck and cone has been used in assem- 'bly of an envelope and a gun in that the axis of the gun was aligned with the axis of the envelope by aligning it with the axis of the neck. The tube envelope offers few reference points which may be used to determine its position accurately while the gun position may be determined by means of the lead pin pattern or a key molded as part f the glass support.

Mass production assembly of envelopes and guns has bee mad with th assistance of aligning fixtures. A fixture, heretofore widely used, located the envelope in position by attachment to the neck of the envelope while the gun was aligned with the neck. The envelope rested upon a plurality of fixture-mounted pads which contacted only the side of the cone, intermediate its ends. A plurality of such fixtures were mounted, on rotatable turret segments for rotation, at the periphery of an indexible turret. Preheating and sealing fires, directed at the neck and gun support, were fixedly mounted adjacent the rest positions of the turret. This former fixture utilized at least three or more support members between the rotatable turret segment and the fixture to hold the envelope without tipping during the preheating and sealing operations. Thus, when the fixture was rotated, these supports were passed through the preheating and sealing fires. The supports repeatedly obscured the fires and interfered With the proper heating of the parts.

Clamping of the neck portion to position the envelope during the entire sealing operation resulted in the introduction of mechanical strain which made themselves manifest in a noticeably increased susceptibility to breakage. To this 'Was added the thermally induced strains caused in part by the non-uniform heating of the neck due to the interruptions of the sealing tires and also in part caused by the non-uniform heat losses due to the neck holding clamps positioned adjacent the heated seal zone.

The trend in the industry has been toward shorter and shorter neck lengths in an attempt to diminish the front to back size of the tubes. With the trend toward the shorter neck, the use of the neck as a reference point has become increasingly more difficult, if not impractical.

Shorter necks have reduced the neck length available for continuous clamping, during the sealing operation, to the point where it is almost completely impossible tohold the neck without continuously interfering with the sealing fires.

It is an object of this invention to position, in a sealing position, cathode ray tube envelopes and the like having a short neck length without the introduction of mechanically induced strains in the neck of the envelope.

It is another object of this invention to reduce the thermally induced strains in the neck portion of cathode ray tube envelopes which are due to non-uniformities in the sealing operation.

It is yet another object of this invention to reduce the number of supports required for an envelope positioner and thereby to minimize the interruptions of the sealing fires occasioned by the rotation of the fixture during the sealing operation.

It is a further object of this invention to accurately position a cathode ray tube envelope while providing access to the neck of the envelope.

The area in which the neck joins the cone is of particular interest to the television set manufacturer who employs the completed tube in a receiver. This area is called the yoke reference zone. It is of particular significance since it is here that the deflection yoke will be positioned when the tube is used. Deflection yokes translate the electrical signals developed by the receiver circuitry into discrete movements of the electron beam which are made visible by the phosphor screen. The location and configuration of this zone with respect to the longitudinal axis of the envelope must be, for this reason, carefully controlled by the envelope manufacturer. The yoke reference zone is substantially symmetrical about the longitudinal axis of the envelope, and the length of the neck is measured therefrom. The contour of the side walls of the tunnel or truncated cone portion of the envelope is not as closely controlled as the yoke reference zone since the walls function merely as spacers to support the faceplate relative to the electron gun. Close control of the yoke reference zone is particularly necessary so that tubes of a particular type, size and deflection angle will be interchangeable without necessitating the use of a specially fitted yoke with each tube. The deflection angle is defined as the angle through which the electron beam must be driven to sweep the screen. Families of tubes have been developed having the same deflection angle and the same yoke reference zone contour.

They may be referred to as degree and degree tubes, for example. The yoke reference zone contour is substantially the same within a family and is dependent upon the deflection angle. I

The above objects and advantages are achieved in one aspect of the invention by the provision, in a positioning device, of a combination comprising support means, article holding means mounted on said support means, article locating means having a configuration substantially complementary to the contour of the article to be held th rB n mountedoh the article holding means, article centering means mounted on the holding means to center the article in the locating means, and clamping means mounted on the article holding means for clamping the article against the locating means.

For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side view of a cathode ray tube envelope;

FIG. 2 is a side elevation of the apparatus;

FIG. 3 is a front elevation, in partial section, of a portion of the apparatus;

FIG. 4 is an exploded perspective view of a portion of the apparatus;

FIG. is a front view of the neck aligning means;

FIG. 6 is a side view of a portion of the article clamping means;

FIG. 7 is a view of the clamp operating means;

FIG. 8 is a side view of another portion of the article clamping means.

Referring to FIG. 1, a cathode ray tube envelope 10 generally comprises a composite structure having a faceplate 12, cone 14, and neck 16. In some cathode ray tube types an internal conductive coating is required and a connector 17, passing through the glass, is employed to allow an electrical connection to be made to the coating. The extent and location of the yoke reference zone is generally indicated at 18 by the phantomed lines.

One aspect of the invention is illustrated in FIG. 2 and includes the combination of support means 20, envelope holding means 22 mounted on the support means 20, envelope locating means 24 having a configuration substantially complementary to the contour of the envelope 10 to be held thereon mounted on the holding means, envelope centering means 26 also mounted on the envelope holding means to center the envelope 10 on the locating means 24, and clamping means 28 mounted on the holding means 22 for clamping the envelope 10 against the locating means 24.

Referring to FIG. 3, the support means includes a pair of spaced vertical rods, 30, 32, which are fixed at one end to a rotatably supported disc or turret segment 34. Disc 34 forms a part of, and is supported by, an indexible turret represented fragmentarily at 36. Turret 36, which is not part of the present invention, is indexible counter-clockwise as shown by the arrow in FIG. 3 and transports the envelope positioning devices past the sealing and preheating fires indicated generally at 37, as will be later explained in detail.

Electron gun inserting spindle 38 is mounted for vertical reciprocating movement at the rotational center of the disc 34. Gun receiving nest 40 is affixed to the spindle 38. Electron gun 42 comprises an electrode structure 44 mounted on a plurality of lead-in pins 46 which have been molded into glass wafer 48. Pins 46 are spaced about the periphery of the wafer 48 in the arrangement typically employed in cathode ray tubes. Means for ascertaining the desired position of the gun 42 may include a variation in the space between two of the pins or the employment of a key, not shown. Nest 40 accurately positions the gun 42 by cooperation with either the pins or the key.

Referring to FIGS. 3 and 4, envelope holding means or carrier 22 is aflixed to the support means 20. The end of the carrier adjacent the support rods 30, 32 is formed in a substantially C-shaped cylinder whose internal wall 50 defines .a substantially cylindrical bore 52 which has a major longitudinal axis. The C-shaped portion is formed by the opposed legs 54, 56, which also define a passageway communicating with bore 52. The upper surface of the carrier 22 is formed with a recess 58 adjacent the bore 52. This recess 58, in the embodiment of the invention shown in the drawings, is filled with a removable spacer 60. A second spacer 62 is positioned in a second recess 64 in the carrier surface. Spacer 62 has a recess 66 formed in its upper surface which corresponds to the recess 58 formed in the carrier. The internal walls of the spacers 60, 62 are contiguous with the wall 50 of bore 52.

Envelope locating means 24 is substantially symmetrical about the axis of the bore 52 and is removably mounted on the spacer 62. One surface of the locating means or locator 24, as shown in FIG. 4, has a projecting lip 68 which mates with the recess 66 in the spacer 62 and also can mate with the recess 58 in the carrier 22. Locator 24 may thus be used directly on the carrier, or on a spacer provided with the proper recess. The outer configuration of the locator 24 also conforms to configuration of recess 64 in the carrier. The upper surface 70 of the locator 24 is contoured to substantially complement that portion of the article which will contact the locator when it is placed in the positioning device. In the embodiment of the invention illustrated the contour of the locator approximates the contour of the yoke reference zone 18 of the envelope 10 and is substantially symmetrical about the longitudinal axis of the bore 52 in the carrier except for that portion which has been removed to allow for the passageway. As previously indicated, the yoke reference zone has been chosen since it is one of the most closely controlled dimensions of the envelope. Other locators 24, having the appropriate contour, may be used to match the contour of the yoke reference zones of other tube types. Envelopes having various neck 16 lengths may be accommodated in the fixture by using a spacer 62 which is long enough to position the end of the neck 16 where desired. Locator 24 and spacer 62 are secured to the carrier 24 by a screw 72. The head of the screw, when in position, is within a recess 74 in the locator whereby it is prevented from contacting the envelope 10. Locators are preferably fabricated from materials having the following characteristics: good stififness, as indicated by a high durometer reading; resistance to high temperature change and deterioration; a relatively high coefiicient of friction; and minimal heat conductivity. Suitable materials which may be used include plastics, metals, or impregnated glass fiber materials which approximate the preferred characteristics. The desirability of these characteristics will be explained during the description of the operation of the apparatus.

Referring to FIGS. 2, 4 and 5, envelope centering means 26 are provided with opposed neck engaging jaws 76, 78 notched as at 79 to receive and center the neck 16. laws 76, 78 are simultaneously operated by a common lead screw 80 by virtue of their mounting upon locks 82 and 84 respectively by screws 85. Lead screw 80 is provided with right and left hand threaded portions so that the complementary threaded jaw mounting blocks 82, 84 will be moved toward or away from one another simultaneously and to the same degree by the rotation of the lead screw 80. Mounting blocks 82, 84 are restrained from rotation about the screw 80 by sliding contact with a base 86. Base 86 is mounted in an indentation 88 on the carrier 22 by screws 90. Lead screw 80 is spaced from the base 86 by bushed bearing support members 92. Collars 94 bear against the supports 92 to prevent lengthwise movement of the lead screw. Knob 96 is attached to the lead screw 80 for manual operation of the lead screw. Location of the aperture formed by the notches 79 in the jaws may be adjusted in one direction by changing the location of the collars 94 on the lead screw. Adjustment of the aperture position in the direction transverse to the length of the lead screw is made by moving the jaws on their mounting blocks. The proper position of the aperture formed by the notches 79 is one which will result in the longitudinal axis of a tubular envelope neck 16 being aligned with the axis of the bore 52.

Referring to FIGS. 2 and 6, vertical staff 98 is secured in a boss 99 on the free end of the carrier 22 with its axis substantially parallel to the axis of bore 52. Arm 100 is mounted for reciprocating movement along the staff 98. Bearings 102 fixed within the arm 100 contact the staff 98 at spaced points to prevent the arm from binding on the staff. Rotation of the arm about the staff is prevented by key 104, attached to the arm by screw 106, which slides in a groove 108 in the staff. Arm 100 is resiliently urged away from the locator 24 by spring 110 which reacts between shaft mounted collar 112 and washer 114.

Referring to FIGS. 2 and 7, collar 116 is secured to the staff 98. Cam 118 is pivotally mounted on collar 116. Handle 120 is secured to cam 118 and allows the operator of the device to rotate the cam about its connection point on the collar 116. Cam 118 has an arm locking flat 121 formed on its periphery. Spring 1111 resiliently urges arm 1% against the cam. Therefore, rotation of the cam 118 by handle 128 causes the arm 188 to be reciprocated toward and away from the locator 24.

Referring to FIGS. 2 and 8, shaft 122 is slideably held for longitudinal movement in bearings 124 contained in the arm 100. The arm 108 positions the shaft 122 so that its longitudinal axis is substantially aligned with the axis of the bore 52 and parallel with the axis of staff 98. Rotation of the shaft in the arm is prevented by the cooperation of a groove 125 in the shaft and arm held stop 126. A vented envelope contacting cup 123, fabricated from resilient material such as rubber, is secured to the shaft 122. Spring 13%, positioned about the shaft 122, reacts between washer 132 and collar 134 mounted on the shaft intermediate the arm 180 and the cup 128. Spring 130 resiliently urges the shaft 122 and cup 128 toward the locator 24. Movement of the cup 128 toward the locator is limited by collar 136 aflixed to the shaft.

The operation of the apparatus may be best understood by beginning the description with the positioning device unloaded, at rest, and with the gun positioning spindle 38 retracted. The positioning devices are equipped for use with a particular cathode ray tube type by inserting the required spacers and a locator 24 which will properly fix the end of the neck 16 with respect to the advanced position of the gun bearing spindle 38. Locator 24 has a contour 70 formed to substantially complement the contour of the yoke reference zone 18 of the particular envelope type and is formed to be substantially symmetrical about the axis of the bore 52. Centering jaws '76, 78 are adjusted so that they will place the envelope neck 16 in alignment with the longitudinal axis of the carrier bore 52.

Envelope It) is placed into the device by passing the neck 16 through the passageway, formed between the ends of the legs 54, 56 and the similarly shaped ends of the spacer 62 and locator 24, until it is in the carrier bore 52. The open height of the positioner, i.e., distance between the cup 128 and locator 24 is made great enough to allow the free passage of the envelope. The envelope is then lowered by the operator until it is resting on the locator 24 with the yoke reference Zone 18 in contact with the contoured portion 70 of the locator 24. This places the longitudinal axis of the envelope transverse to the yoke reference plane and substantially coincident with the longitudinal axis of the bore 52 since the locator is generally symmetrical about the axis of the bore. Envelope centering means 26 are then operated by rotating the knob 96 to cause the lead screw 80 to advance the jaws 76, 78 toward one another. The neck 16 of the envelope is contacted by the notches 79 in the jaws 76, 78. Sufficient force is applied by the operation of the jaws to cause the envelope to shift on the locator 24 until the jaws are stopped as by closing about the neck at that point, neck 16 is in alignment with the axis of the bore 52. This places the longitudinal axis of envelope 1t) essentially along the longitudinal axis of the bore 52 in the carrier 22. Although manual manipulation of the knob 96 has been described, it should be recognized that other means, such as hydraulic operators, may be employed to shift the envelope 10 until the neck is properly positioned within the article receiving bore 52.

After the envelope neck 16 has been aligned and while it is still held by the centering jaws 76, 78 the clamping means 28 is operated. Handle 128 on collar 116 is rotated to pivot cam 118 whereby the arm 188 is moved toward the envelope, compressing spring 110 Arm 100 reaches a locking position when the flat 121 on the cam 118 is in contact with the arm. Flat 121 cooperates with the arm to retain the arm in this position. The movement of arm 181 toward the holding means 22 also brings the cup 128 into contact with the faceplate 12 of the envelope. The structural relationship heretofore described moves the cup 128 along the longitudinal axis of the bore 52 and therefore along the axis of the envelope 10. Continued movement of the arm, after the initial contact, causes spring 138 to compress since cup 128 is arrested by the faceplate. The clamping force generated by spring 130 is applied to the envelope through the faceplate along the longitudinal axis of the envelope 10. The characteristics and initial adjustment of spring 130 determines the pressure applied by the cup to the envelope. Sufiicient force is applied so that friction is generated between the locator and the envelope to prevent the envelope from shifting about its longitudinal axis or from tipping from side to side when the positioning devices are rotated and the turret 36 is intermittently indexed. This is of particular significance in the production of a cathode ray tube employing an envelope having a pass-through connector 17 whose angular position relative to the electrodes in the electron gun 42 is important. Subsidiary alignment devices may be employed to initially align the envelope about its longitudinal axis relative to the gun 42 to properly position the external connector 17 with respect to the gun. Other means, such as fluid motors, may be employed to clamp the article against the locator 24.

After the envelope has been clamped the centering jaws 76, 78 are retracted so that no contact is made with the envelope other than at the yoke reference zone and faceplate. Therefore, no mechanical or thermal strains can be induced in the neck by the centering jaws.

Rotation of the positioning device is commenced, by means not shown, when the device is indexed to the first turret workstation. As the disc 34 rotates, the device support rods 36*, 32 pass through the preheating and sealing fires 3'7. However, minimal interruption of the heating operation is occasioned since only two such supports are employed with each positioning device. The material from which the locator 24 is fabricated must resist deterioration due to heating since it will be heated by conduction from the enevlope. Thermal strains are minimized due to the remoteness of the points of contact of the locator from the seal area and also due to the low heat conduction characteristics of the locator. Satisfactory locators have been fabricated by molding impregnated fiber glass materials.

At subsequent workstations turret activated apparatus, not shown, raises a gun 42, on the spindle 38, into the neck 16 with the wafer 48 positioned adjacent the end of the neck. The sealing fires 37 cause the neck 16 to join to the wafer. At the unload station of the turret 36 the assembled gun and envelope may be removed by unclamping the envelope by operation of handle 128. The assembly is then lifted off the locator 24 and the neck 16 removed from the bore 52 through the passageway. The device is then ready to receive an envelope and gun for the next sealing operation.

The above-described positioning device, by utilization of the yoke reference zone of the envelope for locating and support purposes, has made possible the quantity production of short necked cathode ray tubes.

Although several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

What is claimed is:

1. In a device for positioning a cathode ray tube envelope formed from a faceplate, a glass cone portion aifixed thereto and a neck portion, said envelope having a yoke reference zone formed intermediate said neck portion and said cone portion, said neck and cone having a common longitudinal axis, the combination comprising support means; envelope holding means having a longitudinally extending axial bore and a lateral passageway into said bore, said holding means being mounted on said support means; envelope locating means mounted on said holding means having a lateral passageway substantially coincident with said holding means passageway, said locating means being formed from low-heat conduction material and with a contour substantially complementing the envelope contour at the yoke reference zone; envelope centering means mounted on said holding means for movement between neck engaging and disengaging positions for substantially aligning the neck portion of said envelope with respect to the axis of the bore in said holding means; and envelope clamping means mounted on said holding means for reciprocatory movement in the direction of the axis of said longitudinal bore in said holding means for applying a clamping force to said faceplate along the longitudinal axis of said envelope to hold said envelope against said envelope locating means.

'2. In an article positioning device the combination comprising a pair of spaced supports; an article carrier mounted adjacent the ends of said supports, said article carrier having an end adjacent said supports in the form of a substantially C-shaped cylindrical portion, the internal wall of said portion defining an axial article receiving bore, the ends of the opposed legs of the C-shaped portion defining a passageway communicating with said bore; an article locator affixed to said C-shaped portion having a substantially C-shaped configuration with the upper surface of said article locator contoured to complement the contacted contour of an article to be received thereagainst; a pair of opposed article centering jaws affixed to said C-shaped portion and aligned with said bore operable to engage said article and retractable to a disengaged position; a staff member substantially parallel to said article receiving bore axis mounted at one end on said article carrier; an arm mounted for reciprocating movement along said staff; a first collar adjustably affixed to said staff intermediate said article carrier and said arm; a spring about said staff between said collar and said arm resiliently urging said arm upwardly; a cam follower afiixed to said arm adjacent said staff; a second collar affixed to said staff between said arm and the other end of said staff; a cam pivotally mounted on said second collar in cooperative relationship with said cam follower; a handle amxed to said cam; a shaft mounted on said arm for reciprocating movement in a direction parallel to said staff along the axis of the article receiving bore; a cup mounted on the lower end of said shaft for contacting an article on said locator; a third collar on said shaft intermediate said cup and said arm; a spring about said shaft intermediate said third collar and said arm resiliently urging said cup away from said arm; and a fourth collar about said shaft intermediate the upper end of said shaft and said arm to limit the movement of said shaft, whereby an article may be clamped against said locator.

References Cited in the file of this patent UNITED STATES PATENTS 1,602,509 Six Oct. 12, 1926 2,058,719 Pigman Oct. 27, 1936 2,323,450 Brosco July 6, 1943 2,685,059 Pierce et al. July '27, 1954 FOREIGN PATENTS 160,419 Switzerland May 16, 1933

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