US3259224A - Sensing device for color tube apparatus - Google Patents

Description

July 5, 1966 J, PEKQSH 3,259,224

SENSING DEVICE FOR COLOR TUBE APPARATUS Filed Aug. 25, 1964 3 Sheets-Sheet 1 30a 1 30b FIG. 1 A

i =2 QIF-QD 9 :5 Q1 f QE 51 m FIG. 3 70f I 79 70h I I /"7oe INVENTOR.

: fgaymonci If Pakofih July 5, 1966 R. J. PEKosH 3,

sENsING DEVICE FOR COLOR TuBE'APmRATus Filed Aug. 25, 1964 s Sheets-Sheet 2 July 5, 1966 R. J. PEKOSH 3,259,224

SENSING DEVICE FOR COLOR TUBE APPARATUS Filed Aug. 25, 1964 a Sheets-Sheet a FIG. 4

United States Patent 3,259,224 SENSING DEVICE FOR COLOR TUBE APPARATUS Raymond J. Pekosh, Chicago, Ill., assignor to The Rauland Corporation, Chicago, 111., a corporation of Illinois Filed Aug. 25, 1964, Ser. No. 392,010

8 Claims. (Cl. 19819) The present invention is directed to a system that is especially suited for controlling cathode-ray tube processing apparatus.

A highly automated apparatus for performing the screening process of a tricolor cathode-ray tube is described and claimed in application Serial No. 391,864, filed concurrently herewith in the name of Joseph P. Fiore and assigned to the same assignee as the present invention. As described in that application, a multiplicity of workholders are arranged to convey the cap or screen section of the color cathode-ray tube through a series of automated work stations where the various processing steps, leading to the deposit of phosphor triads on the screen, are carried out. To attain maximum efficiency, these stations are programmed to perform their various assignments automatically when a workholder has been brought to a stop within each such station. If for any reason a Workholder should be presented to these stations without having the cap or screen section of a tube positioned within it, there would be an undesirable dispersion of materials within the apparatus unless provision were made to interrupt the work function of any such station which is called upon to perform its process in the presence of a workholder that does not bear the cap section of a color cathode-ray tube. The present invention addresses itself to this problem and provides a control system to obviate such undesired results. It is, therefore, a principal object of the invention to provide a system for controlling the processing apparatus for cathode-ray tubes.

It is :a specific object of the invention to provide a system for controlling the processing functions of a screening apparatus for color cathode-ray tubes.

Another specific object of the invention is to provide a control system which permits the screening apparatus in a color tube plant to perform its functions only when there has been presented a tube section or component upon which the work may be conducted. The control is on a per-station basis and the work function is interrupted at only those stations which do have a tube component for processing.

Accordingly, the control system of the invention is associated with a cathode-ray tube processing apparatus having a conveyor which transports a multiplicity of workholders through a plurality of work stations. The control system comprises a probe for sensing the presence of a cathode-ray tube component within a workholder. The probe is supported adjacent the conveyor and is movable from a rest position to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray tube component. An actuator yieldably advances the probe from its rest position toward its actuated position. There are means for energizing this actuator in timed relation to the movement of the conveyor in order to effect sensing of the workholders by the probe on an individual basis. There is a control member for each of the workholders, movable with the conveyor ice and displaceable into a position to control the processing function conducted in at least one, but preferably in all, of the automated work stations. Finally, there are means, responsive to the position attained by the probe during sensing, for determining the position of the control member associated with the workholder instantaneously sensed by the probe.

The features of the present invention Which are believed to be novel are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings, in the several figures of which like reference numerals identify like elements, and in which:

FIGURE 1 is a plan view of a screening layout for depositing phosphor dots on the screen section of a color cathode-ray tube;

FIGURE 2 is a view, partially broken away, showing structural details of one of the conveyors of FIGURE 1;

FIGURE 3 is a top view of the control member or flag of a screening cart for the conveyor of FIGURE 1; and

FIGURES 4-6 are detailed views of the control arrangement of the invention for sensing the workholders of the screening carts included in the screening conveyor.

The layout of FIGURE 1 represents screening apparatus for applying deposits of phosphor to the end cap or screen section of a color cathode-ray tube. It illustrates the same type arrangement as described in the Fiore -appli-. cation but simplified to show merely two screening conveyors and one light-exposure conveyor. These components cooperate in laying down one family of phosphor dots on the tube screen although a complete screening arrangement deposits three similar and interlaced families of phosphor dots characterized by emitting radiations of green, blue and red in response to the impingement of a cathode-ray beam. Since the control system of the present invention may be completely understood from consideration of so much of the screening plant as deposits the green phosphor dots, the illustration of FIGURE 1. has been confined accordingly. Reference may be had to the Fiore application for a disclosure of the screening arrangement in its entirety.

The screening apparatus, as shown, comprises two similar endless conveyors 30a and 30b, individually in the form of a closed, elongated loop arranged in alignment with their longitudinal axes in parallel relation with one another. Each such conveyor has a series of screening carts having workholders for individually supporting the screen section of a color television tube and for transporting the screen from a loading station through a multiplicity of screen processing stations to a discharge station of that conveyor. The small rectangles 31 represent the screening carts of each conveyor and each such cart has its own workholder as will be described more particularly hereinafter. Thirty such carts are represented in each of, the screening conveyors and the conveyors each have an intermittent or step-by-step indexed type of drive from which it may be said that there are 30 stations on each conveyor devoted to loading, work processing and discharge or un-,

loading. The lettered circles depict specific ones of these stations and similar designations as between the several conveyors designate like stations from the standpoint of manipulation or work process conducted. The following table assigns for each station the process step that takes place, the angle of the axis of rotation of the tube screen in that station relative to vertical and the speed of rotation of the screen about its central axis, that is to say, the axis that corresponds to the longitudinal axis of the tube into which the screen is ultimately assembled. The details by which varying speeds and varying angles of tilt are imposed on the work table are of no consequence to the present invention and are explained in the Fiore application.

The cross-hatching of the screening conveyors 30 in FIGURE 1 represents a housing of vertical walls and because of the housing the sides of each conveyor loop are enclosed. It is desirable, of course, that the enclosing walls be transparent at least in part to permit observation of the work functions being carried out. The end portions of each conveyor loop, however, are exposed because the operations performed there are manual, namely, those of loading, unloading and inspection.

In addition to screening conveyors 30 there is shown an endless conveyor 32, referred to as a merry-go-round, having a loading station Q and a discharge or unloading station R. The merry-go-round is positioned with its terminal stations Q, R displaced between and adjacent the end portions of screening conveyors 30a, 30b to the end that the discharge station M of screening conveyor 30a is in close physical proximity to loading station Q of merry-goround station 32. Moreover, discharge station R of this merry-go-round is similarly located in close proximity to loading station A of screening conveyor 30b.

The merry-go-round has a series of light-exposure housings 33 popularly referred to as exposure carts, the details of which are of no particular concern to the subject invention. Suflice it to say that each cart supports and selectively exposes predetermined portions of a photosensitive coating which has previously been deposited on the tube screen section accommodated by a particular cart. The exposure is accomplished as the merry-go-round transports that exposure cart with a screen section from the loading station of the merry-go-round to its discharge station. Of course, the photosensitive resist materials which are normally deposited along with the phosphor coating material on the screening conveyor have a predetermined development time and the speed of the merry-go-round is preferably -adjusted so that the travel from load to discharge'takes at least this same amount of time. It is also desirable to relate the movement of the merry-go-round to the movement of the screening conveyors. Since a series of discrete processing steps of very different types are carried out in the many stages of each screening conveyor, it is most convenient that the screening conveyors have an intermittent or step-by-step drive represented as unit 45 in FIGURE 2. Such driving mechanisms which step a conveyor intermittently under the control of a programming arrangement are well known in the art. The details of the intermittent drive and the programming arrangement constitute no particular part of the subject invention and, therefore, have not been disclosed in detail.

It is preferred that the merry-go-round have an effective index time that is related to the index time of the screening conveyors with which it is associated. The eifective index time of the merry-go-round is the time required for an exposure cart to travel from a given point in discharge station R to the corresponding point in loading station Q. In particular, the exposure cart preferably advances from its discharge to its loading station in a time equal to or less than the index time of the screening conveyors. This may be easily accomplished by having a continuous motor drive for the merry-go-round with a gear reduction system to attain the requisite speed of the exposure housings. When the index time of the merry-go-round is less than that of the screening conveyor, it should be divisible equally into the screening conveyor index time. For example, the merry-go-round indexing may be twice as fast as that of the screening conveyor.

Overall operation In considering the overall operation of the described arrangement, it will be understood that it is essential to maintain as clean an atmosphere and environment as practicably possible. Accordingly, the conveyors are housed in a room that is kept clean and has carefully protected entrances to preserve its cleanliness. The preferred apparatus and arrangement for maintaining an essentially clean environment for the work stations of the screening conveyors is the subject of an application filed concurrently herewith in the name of Joseph P. Flore et al., Serial No. 391,985, assigned to the same assignee as the present invention. It is sutficient to say that the portions of the screening conveyors 30 that are enclosed by the housing of the conveyor are constantly bathed in a controlled stream or flow of precisely conditioned air.

Each screening conveyor is driven in the direction indicated by the arrows by a conventional index type of intermittent or step-by-step drive. It has been found that an index interval of approximately 28 to 30 seconds is adequate.

It is also preferred that interlocks be provided at any station where, in conducting the work assigned to that station, mechanism of any kind is advanced into the path of travel of the screening carts or the screen sections mounted thereon. The interlock may take the simple form of a microswitch which in its open condition causes the index drive of the conveyor to be interrupted but the microswitch is closed by the return of the movable components of the working station to their normal or rest positions clear of the path of travel of the screening car-ts and the screen sections under process. Illustrative use of the interlock switch will be described hereafter but it is not believed necessary to show the electrical system of the index drive incorporating the protection of the interlocks. Their association would be essentially that of a series circuit, requiring all interlocks to be closed before the indexing circuit is permitted to perform.

Merry-go-round 32 rotates continuously in the direction indicated by the arrow and at a speed to correlate lighthouse loading to screen conveyor unloading as described above.

In operation, the screen sections to be processed are delivered to loading station A of screening conveyor 30a by a conveyor feeding in the direction of arrow 34a. As color tubes are currently made, the screen section is the cap of the envelope with a surface to bear the phosphors and a peripheral flange through which the screen section may be integrated with the funnel and neck section by a sealing process. It has been determined that optimum results are attained through the practice of pairing by which is meant that each screen employs its own shadow mask as an exposure device in the screening process and, therefore, each cap delivered to the screening room has its mask along with it.

The operator loads a screen section onto a screening cart at station A of conveyor 30a and also loads its mask on the same screening cart. The conveyor then indexes to position B where the cart is sensed to determine whether or not it bears a screen; if it does, that cart will proceed through the work stations and the screen which it carries will receives the various processing steps. On the other hand, if the screening cart does not carry a screen section, a control to be described later is accomplished which disables the function of the various work stations as this particular cart passes through.

Assuming that the screening cart to be followed through the conveyor by way of illustration does have a screen section, after leaving sensing station B, it advances to stations C where it is detergent washed by a high velocity spray and is then rinsed at station D with warm deionized water. The screen is subjected to a spray of polyvinyl alcohol at station E. In the next stations F, the panel is dried by infrared heaters which may be positioned on the wall sections enclosing the conveyor. At station G, cooling is initiated and a fan may be employed to direct conditioned air, which is bathing these stations, more particularly into the screen section. Further cooling is accomplished at station H and the screen is manually inspected at stations I. If any defect is observed, the screen is unloaded and its cart is manually adjusted to disable the automatic processing apparatus at subsequent stations but only while this cart is present in any such station. On the other hand if the screen passes inspection, it continues through the work stations on the other side of the conveyor. Station H is for further cooling and at station B a further sensing operation takes place. Sensing at this station is a mere precaution and may be omitted, relying on the inspector to adjust any screening cart which has carried a screen section that failed to pass inspection.

At station I, a charge of slurry is deposited on the screen. This slurry contains green phosphor material as well as a photosensitive resist and the rotation of the workholder on the screening cart distributes the slurry evenly across the entire screen section. At the next station K, a probe in the form of a cylindrical tube is lowered into the rotating screen to collect or reclaim excess slurry, the slurry being displaced into the tube through centrifugal force and gravity and returned to a reservoir in a closed circulating system.

After preliminary drying at station F with infrared heaters, the cap advances to station L where a trim probe is introduced over the skirt of the panel. The trim probe is a water jet which cuts the slurry deposit just above the meeting line of the screen and its peripheral flange. Following the trim step, the panel is further dried at stations F and cooled in the final stations H from which it advances to discharge station M.

The screen section with its mask has now completed a traverse of the first screening conveyor and is ready for exposure. The mask is first positioned within the, screen section and the assembly is removed from conveyor 30a and placed on the exposure cart instantaneously at loading station Q of merry-go-round 32.

Since the cap to be exposed on merry-go-round 32 bears a coating containing green phosphor, the light source in each cart of that merry-go-round is positioned to simulate the location of the green gun in the finished tube,

assuming that the process is directed to the production of a three-gun shadow mask tube. The screen section under consideration is subject to exposure in its cart in order to locate the dots of green phosphor on the screen. Each cart has its own timing device which may be a chronometer or may be a light integrator. The first maintains an exposure for a fixed period of time .and the latter maintains an exposure sufiicient to achieve a desired total integration of incident light. Generally, operating times can be established that permit use of a timing or clock mechanism on the exposure cart. The clock mechanism removes a shutter from the lightpath of a high pressure mercury lamp as the cart leaves loading station Q and returns the shutter to block that lightpath after the selected exposure interval which will be no more, and generally less, than the time required for this lighthouse to arrive at discharge station R. The exposed screen section with its mask, through which it has been exposed, is now removed from the cart and loaded onto the screening cart at station A of screening conveyor 30b. Of course, the mask is removed from the panel and stored on the screening cart, leaving the panel free for further processing.

Generally, the same steps are carried out on screening conveyor 30b except that the pass from the loading station A to inspection station I is devoted to developing of the green dots. In developing stations N, a spray of warm deionized water, carefully controlled as to pressure, temperature and pattern, removes all except the exposed portions of the phosphor coating that had been applied to the screen on the preceding conveyor 30a. This results from the fact that the exposure of the photoresist in the exposure cart causes the desired dots to be insoluble in Water whereas the unexposed portions of the coating remain soluble and, therefore, they wash off at stations N. Concurrently, a water stream directed at the flange of the screen section removes any unwanted residue of green phosphor coating.

The inspector at station I determines whether or not a satisfactory pattern of green dots has been laid down on the screen. If not, that screen is rejected; otherwise, it proceeds down the other side of conveyor 30b and undergoes essentially the same processing steps as took place in its travel through the corresponding portion of the preceding conveyor. This time, however, the coating includes a blue, rather than a green, phosphor.

It is not necessary to continue the description of the process steps for developing the families of blue and red phosphor dots. They are generally similar to those previously describe-d.

It is desirable to consider certafn details of screening conveyors 39 in order to develop the environment of the control system of the present invention which determines Whether or not work functions are carried out in the various automated stations of the conveyor. As shown in FIGURE 2, the conveyor is structurally supported from the floor 39 of the screening room and the movable mechanism of the conveyor comprises two link chains 41, 41a concurrently driven by sprocket wheels 43, 43a. The chains themselves are of conventional construction. The drive of the sprocket wheels is from a motor 44 through an indexed intermittent drive 45 designed to rotate each gear in each step of the index program. Both the upper and lower conveyor chains have provisions through which many screening carts are mounted thereto. As shown, the screening cart 70 has a mechanical connection 79a with the upper conveyor chain and another mechanical connection 761) with the lower chain. Preferably and as described in the Fiore application these are removable connections to facilitate removing the screening cart 70 from the convey-or.

Details of screening cart '70 are disclosed and claimed in an application, Serial No. 391,985, filed concurrently herewith in the name of Joseph P. Fiore et a1. and, likewise, assigned to the same assignee of the present invention. It is only necessary here to understand that each screening cart 70 has a workholder 73 by means of which the screen section 26 of a color cathode-ray tube is conveyed through the screening machine. This screening arrangement contemplates pairing which entails the use of an aperture mask in developing the family'of phosphor dots on screen section 26. Accordingly, each screening cart also accommodates the mask 25 associated with the cap section 26 that is being processed. The workholders are of the open-frame type being formed of a spider of three arms, two of which appear in FIGURE 2. The arms have .a displacement of about an axis of rotation and the workholder is mounted on screening cart 70 to be rotated at a controlled'speed. While the mechanical drive for the workholder is fully described in the Fiore et al. application, it is of no concern to the present invention.

There is a control member for each workholder movable with the conveyor and displaceable into a position to control the processing function conducted in at least one, but preferably in all, of the automated work stations of the screening conveyor. This control member 700, usually referred to as a flag, is shown in FIGURE 3. It is an overcenter arrangement of springs 70 which causes the flag to be a two-position device. The flag has a pivot pin 70g rotatably secured between fingers 7011 which are integral parts of screening cart 70. Forwardly of pin 70g the flag carried an anchor pin 7tlj for springs 70 This is a well recognized overcenter construction and permits the flag to have two discret positions, one above and the other below the plane of pivot pin 70g.

Sensing Obviously, if a screening cart should go through the various work stations of any screening conveyor without carrying a cap or screen section 26 to be Worked upon, there would be both a waste and a highly undesirable dispersion of slurry and fluids on the conveyor. In order to avoid any such undesirable result, and in accordance with the invention, each screening conveyor has a control system which determines whether or not the work process is to be carried out at the various stations,

The control system comprises a probe for sensing the presence of a tube cap within the workholder. Referring to FIGURES 4-6 which represent the control system, a plurality, specifically two, probes 80, 80 are provided being slidably mounted within a frame 800 of U-shaped configuration with its arms apertured to accommodate probes 80. As indicated in FIGURE 4, the probes are supported adjacent the screening conveyor and in particular adjacent the lowermost portion of workholder 73 here shown in the angular relation that it assumes in sensing station B of each screening conveyor. The slidable mount for the probes permits them to be movable from a rest position shown in full-construction line in FIGURE 4 to a fully actuated position designated by the broken-construction line in the same figure which either probe may assume only if the workholder being sensed does not contain a cathode-ray tube component, specifically, a cap or screen section 26.

In order to accomplish their sensing function, the probes may be displaced by an actuator which yieldably advances the probes from their rest toward their fully actuated positions. The actuator illustrated includes an air cylinder 80b having a piston Site with a rod 8ld mechanically connected to a flange of member 80a. A pair of guide rods Sile, positioned on opposite sides of and in parallel relation to the air cylinder and its piston, extend through apertures of member 80a and provide rails upon which that member may readily slide under the influence of piston 80 as it is displaced within its cylinder. These rods are supported on a stationary frame 79. Piston displacement is accomplished in the usual way of a hydraulic motor by means of an air valve 80 which may be operated to displace the piston to the right as viewed in FIGURE 4 and by a second air valve 805; operated to restore the piston to a rest position, retracting the probes from the path of the workholders. While there is a positive connection between member 80a and piston rod 80d, the coupling to the probes is a yieldable one afforded by coil springs 8011 which are concentrically arranged relative to the probes. At one end each of the springs abuts a flange of member 80a and at their opposite ends they engage a washer or other stop element Sfij mechanically connected to each probe.

There is need of means for energizing the hydraulic actuator in timed relation to the movement of the screening conveyor to effect sensing of the workholders, one at a time, by probes 80. The actuator might readily be energized by a trip to be engaged by a workholder as it approaches station B but it is just as convenient to include a control circuit within indexing control system 45 to time the operation of valves and 80g in a desired sequence relative to the entry and departure of a workholder from sensing station B.

The information obtained from sensing of the workholder is utilized to displace a control member provided for each of the workholders and displaceable into a position to control the processing function conducted in at least one of the work stations of the conveyor but preferably controlling the work functions in all of the automated stations of the conveyor. The control member on each screening cart is the element or flag 70e described hereinbefore in relation to FIGURE 3. With reference to FIGURE 3, the flag travels in the direction indicated by an arrow as the screening cart is advanced with the conveyor. With the flag in its rest position, it passes above the level of a microswitch '79 located at each automated work station to control its process. On the other hand, if the flag has been displaced into its actuated or effective position, it bears against microswitch 79 as the screening cart moves along, closing the switch to initiate the work function at this automated station.

There are means to establish flag 70a in its rest position prior to the entry to station B of the screening cart with which it travels. Again, this function may be accomplished from the programming system of index 45 but it is just as convenient in this case to arrange a cam block 80k (FIGURE 2) on the frame of the screening conveyor in the path of flag 70a mechanically to displace the flag to its rest position after the screening cart leaves the final processing station.

Additionally, the control system has means, responsive to the position attained by probes 80 during sensing, for determining the position of flag 70s. This control means has a pair of switches Sill having a switch operator 80m in alignment with each of the probes for actuation thereby. As indicated in FIGURE 6, switches 80! are series connected in a control circuit for energizing a solenoid 8t). Energization of the solenoid displaces its armature which moves flag 70e from its rest position (FIG- URE 6) to its actuated position.

It is prudent to provide an interlock at the sensing station so that indexing of the conveyor may only take place if the sensing operation has been completed and the probes restored to their rest position of FIGURE 4. Such an interlock is represented at 80p. It is a microswitch included in the programming drive control of the conveyor and, physically, it is in the path of an abutment 801' on member 80a which closes switch 80p when that member has been returned to its home position.

In operation, the programming system of index 45 operates valve 80 to advance probes 80 toward a workholder after that workholder has been stopped in sensing station B. Since the workholder has a frame or spiderlike structure, the pair of probes, displaced relative to one another in the direction of movement of the conveyor, is a precaution against the possibility that a single probe may engage the workholder rather than sensing for a screen cap 26 within the workholder.

As piston 86d advances to the right, displacing member 80a in the same direction, the probes move from their rest toward their fully actuated positions. If the workholder does, in fact, contain a tube cap, both probes engage the cap in normal operation as represented in FIGURE 5. This arrests their further movement prior to the complete travel of piston 80d to the right. As a consequence, in the continued movement of member 80a by the air cylinder the switch operators 80m are engaged by the ends of probes 86. The switch operators may conveniently terminate in rollers which roll up upon the probes, rotating the switch operators and closing the switches. If both are closed, solenoid 801i is actuated and flag 70s of the screening cart is moved to its operative position. Immediately thereafter valve 80g operates to restore the mechanism to the position shown in solid outline in FIG- URE 4. In so doing, it causes abutment 80r to close microswitch 80b and permit the indexing of the conveyor to continue.

In case the workholder does not, in fact, contain a tube cap, at least one of probes'80 is permitted to advance to its fully actuated position. In such case, the switch operator 80m associated with that probe is not actuated; the energizing circuit of solenoid 80n is not completed and flag We is retained in its rest position. Accordingly, the further progress of the screening cart through the conveyor does not occasion actuation of the automated work processing apparatus in the various stations.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

I claim:

1. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders through a plurality of work stations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component within a workholder, supported adjacent said conveyor and movable from a rest position to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor to effect sensing of one of said workholders by said probe;

a control member for each of said workholders, movable with said conveyor, and displaceable into .a position to control the processing function conducted in at least one of said work stations;

and means, responsible to the position attained by said probe during sensing, for determining the position of the control member associated with the workholder instantaneously sensed by said probe.

2. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders through a plurality of work stations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tube component within a workholder, supported adjacent said conveyor and individually and independently movable from a rest position to a fully actuated position to a fully actuated position which each may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probes simultaneously from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor to effect sensing of one of said workholders by said probes;

a control member for each of said workholders, movable with said conveyor, and displaceable into a position to control the processing function conducted in at least one of said work stations;

and means, responsive to the positions attained by said probes during sensing, for determining the position of the control member associated with the workholder instantaneously sensed by said probes.

3. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of open frame workholders through a plurality of work stations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tube component within a workholder, spaced from one another in the direction of travel of said workholders, supported adjacent said conveyor and individually and independently movable from a rest position to a fully actuated position which each may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probes simultaneously from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor to effect. sensing of one of said workholders by said probes;

a control member for each of said workholders, movable with said conveyor, and displaceable into a position to control the processing function conducted in at least one of said work stations;

and means, responsive to the positions attained by said probes during sensing, for determining the position of the control member associated with the workholder instantaneously sensed by said probes.

4. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of open'frame workholders through a plurality of work stations, a control system comprising:

a plurality of probes, for sensing the presence of a cathode-ray tube component within a workholder, spaced from one another till the direction of travel of said workholders, supported adjacent said conveyor and individually and independently movable from a rest position to a fully actuated position which each may assume only if the workholder being sensed does not contain .a cathode-ray tube component;

an actuator for yield-ably advancing said probes simultaneously from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor .to eflect sensing of one of said workholders by said probes;

.a control member for each of said workholders, movable with said conveyor, and displaceable into a position to control the processing function conducted in at least one of said work stations;

a plurality of switches individual-1y 'actuable between open and closed conditions in accordance with .the position attained by an assigned one of said probes during sensing;

and a control circuit including said switches in series for determining the position of the control member associated with the workholder instantaneously sensed .by said probe.

5. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders through a plurality of Work stations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component within a workholder, supported adjacent said conveyor and movable from a rest posi- -tion to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray (tube component;

an actuator for yieldably advancing said probe from said rest position towards said actuated position;

means for energizing said actuator in timed relation :to the movement of said conveyor to effect sensing of one of said workholders by said probe;

a control member for each of said workholders, movable with said conveyor, and displaceable into a position to control the processing function conducted in at least one of said work stations;

at least one switch associated with said probe to assume an open condition when said probe advances .to its fully (actuated position and otherwise to assume a closed position;

and a control circuit including said switch for determining the position of the control member associated with the workholders instantaneously sensed by said probe.

6. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders through a plurality of work stations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component Within a workholder, supported adjacent said conveyor and movable from a rest position to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor to effect sensing of one of said workholders by said probe;

a control member for each of said workholders, movable with said conveyor, anddisplaceable from a rest position into an actuated posit-ion in which it is effective to initiate the work function conducted in at least one of said work stations along the conveyor path subsequent .to the location of said probe;

at least one switch associated with said probe to as sume an open condition when said pro-be advances to its fully actuated position and otherwise to assume a closed position;

and a control circuit including said switch for displacing to its aforesaid actuated position the control member associated with the workholder instantaneously sensed by said probe.

7. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders through a plurality of work stations, a control system comprising:

a probe, for sensing the presence of a cathode-ray tube component within a workholder, supported adjacent said conveyor and movable from a rest position to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for yieldably advancing said probe from said rest position towards said actuated position;

means for energizing said actuator in timed relation to the movement of said conveyor to effect sending of one of said workholders by said probe;

a control member for each of said workholders, movable with said conveyor, and \displaceable from a rest position into an actuated position in which it is effective to initiate the work function conducted in at least one of said work stations along the conveyor path subsequent to the location of said probe;

means for establishing the control member of each workholder to its rest position as its assigned workholder approaches the location of said probe;

at least one switch associated with said probe .to assume an open condition when said probe advances to its fully actuated position and otherwise to assume a closed position;

and a control circuit including said switch for displacing to its aforesaid actuated position the control member associated with the workholder instantaneously sensed by said probe.

8. In cathode-ray tube processing apparatus having a conveyor transporting a multiplicity of workholders througha plurality of work stations, a control system compnsmg:

a probe, for sensing the presence of a cathode-ray tube component within a workholder, supported adjacent said conveyor and movable from a rest position :to a fully actuated position which it may assume only if the workholder being sensed does not contain a cathode-ray tube component;

an actuator for y-ieldably advancing said probe from said rest position towards said actuated position and tor returning said probe to its rest position;

means for energizing said actuator in timed'relation to the movement of said conveyor to effect sensing of one of said workholders by said probe;

a control member for each of said work-holders, movable with said conveyor, and displaceable from a rest position into an actuated position in which it is effective to imitate the work function conducted in at least one of said work stations along the conveyor path subsequent to the location of said probe;

means for establishing the control member of each workholder to its rest position as its assigned workholder approaohes the location of said probe;

at least one switch associated with said probe to assume an open condition when said probe advances to its fully actuated position and otherwise to assume a closed position;

a control circuit including said switch for displacing to its aforesaid actuated position the control member associated with the workholder instantaneously sensed by said probe;

a driving system for said conveyor for advancing said workholders step by step through said work stations;

.an interlock switch .to be closed to energize said driving system;

and .a switch operator movable with said probe for closing said interlock switch when said probe is in its aforesaid rest position.

References Cited by the Examiner UNITED STATES PATENTS 2,376,980 5/1945 Petersen 1182 SAMUEL F. COLEMAN, Primary Examiner.

E. A. SROKA, Assistant Examiner.

Claims (1)

1. IN CATHODE-RAY TUBE PROCESSING APPARATUS HAVING A CONVEYOR TRANSPORTING A MULTIPLICITY OF WORKHOLDERS THROUGH A PLURALITY OF WORK STATIONS, A CONTROL SYSTEM COMPRISING: A PROBE, FOR SENSING THE PRESENCE OF A CATHODE-RAY TUBE COMPONENT WITHIN A WORKHOLDER, SUPPORTED ADJACENT SAID CONVEYOR AND MOVABLE FROM A REST POSITION TO A FULLY ACTUATED POSITION WHICH IT MAY ASSUME ONLY IF THE WORKHOLDER BEING SENSED DOES NOT CONTAIN A CATHODE-RAY TUBE COMPONENT; AN ACTUATOR FOR YIELDABLY ADVANCING SAID PROBE FROM SAID REST POSITION TOWARDS SAID ACTUATED POSITION; MEANS FOR ENERGIZING SAID ACTUATOR IN TIMED RELATION TO THE MOVEMENT OF SAID CONVEYOR TO EFFECT SENSING OF ONE OF SAID WORKHOLDERS BY SAID PROBE; A CONTROL MEMBER FOR EACH OF SAID WORKHOLDERS, MOVABLE WITH SAID CONVEYOR, AND DISPLACEABLE INTO A POSITION TO CONTROL THE PROCESSING FUNCTION CONDUCTED IN AT LEAST ONE OF SAID STATIONS; AND MEANS, RESPONSIBLE TO THE POSITION ATTAINED BY SAID PROBE DURING SENSING, FOR DETERMINING THE POSITION OF THE CONTROL MEMBER ASSOCIATED WITH THE WORKHOLDER INSTANTANEOUSLY SENSED BY SAID PROBE.

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