FR2471040A1 - Automatic assembly for leaf spring mounted TV masks - uses movable mask and screen supports with cams for springs to and from screen mounts - Google Patents

Abstract

A mash is supported by leaf springs engaging over lugs on the screen, by an appts. which comprises a screen, an upper support frame supported on ballas and a rigid lower support frame to allow accurate positioning of the screen. A vertically movable plate, supported below the lower frame edge region carries a number of slides movable in three right angled directions. Each slide carries a resilient cam contoured to hook behind a mash leaf spring adjacent the screen lug and a hook which hooks behind the spring free end. Retraction of the slide draws the leaf spring off the lug so that automatic mounting and dismounting of the mash can be effected. The movement of the slides allows accurate positioning for different sized mashs.

Description

 The subject of the present invention is a method, a machine and a device for automating assembly and disassembly operations, a mask inside the screen panel during the manufacture of a color television tube.

 One of the essential operations of manufacturing a color television tube is the formation on the inner face of the bottom of the glass envelope or screen slab of the phosphor network tube of the three complementary colors which allow by excitation by the three barrels separated from the tube to constitute the color image.

To build this network, we usually proceed as follows.

 The composition of phosphors corresponding to one of the three colors used is deposited on the internal face of the screen panel. This layer of phosphors is then exposed through the shadow mask mounted inside the slab from a simulator mounted in the position where the barrel of the corresponding color will be placed in the finished tube.

The mask is removed and the lion carries out the fixation operation of the insolated phosphors, then washing the slab. Thus, the first network of phosphors of a given color is formed.

 These operations are repeated twice successively for the phosphors of the other two complementary colors, each time carrying out the sunshine through the mask put back in place and a simulator mounted in a position corresponding to the barrel which will excite the phosphors of the corresponding color in the tube. completed.

 After these three successive operations of deposition, exposure, fixing and washing, an aluminization is carried out under vacuum at the bottom of the screen slab to increase the brightness of the tube.

It therefore appears that in such a manufacturing process, it is necessary to carry out at least four times the establishment or assembly of the shadow mask in the screen slab and then the disassembly of these two constituents of the tube to allow the three successive formation operations. phosphors and then alumination before the last assembly of the mask in the screen slab after which the mask will be permanently welded in place in the slab.

Given the extreme precision with which the mask must be positioned in the screen slab in order to obtain the best juxtaposition of the three networks of colored phosphors, without overlap, it appears that these operations are very delicate and that the tolerances d assembly must be reduced to a minimum
On the other hand, it is necessary to avoid, during the successive assembly and disassembly operations of the mask in the screen slab, that the layer of phosphors and finally of aluminum deposited inside the screen slab is not scratched or locally damaged, with the consequence of manufacturing defects leading to rejection of the tube or the creation of free particles considerably detrimental to the quality of the tubes manufactured.

Also, because the mask is very fragile and that the slightest impact will make it unusable, it is absolutely necessary to avoid any risk of contact during assembly and disassembly of the mask with the screen panel or with any foreign part, such as in particular that 'a tool
The object of the invention is to allow complete automation of the assembly and disassembly operations of the mask in the screen slab, prior to the final operation of sealing the mask in the slab, with a view to better precision and manufacturing quality, in particular reducing rejects by deformation of the mask or deterioration of the screen slab and avoiding the risks of the formation of free particles inside the tube as a result of accidental friction of a tool in the screen slab or walls of the mask frame inside the walls of the screen slab.

The method according to the invention for automating the assembly and disassembly operations of a mask inside the screen panel during the manufacture of a color television tube of the type comprising spring blades mounting the mask in the screen which positions the mask in the screen when these parts of said spring blades cooperate with complementary parts of said screen slab is characterized according to the invention in that
for disassembly of the mask from the screen slab
- the assembly is positioned on a support frame of an assembly and disassembly machine,
- an assembly pre-centering is thus positioned on said frame,
- We just take I1 together from below by means of a tool which flexibly engages behind each leaf spring between said blade and the internal wall of the screen slab to come into abutment at the end of the race against the aforementioned cooperating parts of connection between said blades and said screen slab simultaneously centering said assembly on said tool,
- said blades are then retracted inwards, releasing said cooperating parts from said blades and from said screen panel,
- Then said mask is lowered under said screen slab, and for 11 assembly
- the mask is introduced on 11 tools,
- the screen slab is positioned on said support frame of the assembly and disassembly machine
- a pre-centering of the screen slab is carried out on said frame,
- said blades are retracted inwards,
said tool carrying said mask is raised until it abuts against the aforementioned cooperating connecting parts secured to the screen slab Simultaneously centering the assembly and the tool,
the blades are released outwards until said cooperating connecting parts between said blades and said screen slab cooperate,
- 1 set of the mask and the screen screen is vibrated,
- and the tool is removed.

The invention also relates to a machine allowing the implementation of the aforementioned method, this machine is characterized in that it comprises
a support frame capable of supporting the screen slab of a tube while leaving free access under the interior volume of the screen slab,
a tool capable of going up and down below said support frame, said tool comprising supports for the mask, cam-shaped means for engaging behind said leaf springs said parts integral with the screen slab such as studs cooperating with said parts such as openings of said spring blades, and slides of which a curved hook end engages behind each blade and is capable of folding said blade inward when the slide is retracted. Advantageously, the tool will comprise as many cams and slides as the masks comprise dedicated leaf-springs, the same tool being moreover adaptable to several types or dimensions of tubes.

 According to another characteristic of the machine, the cams are mounted with a certain movement of flexible movement on the tool, tending to engage in pressure behind said leaf springs when said cams are engaged from below behind said leaf springs.

Such an arrangement allows great flexibility in the use of the machine and ensures its immediate adaptation even with tubes having relatively large manufacturing tolerances with regard to the positioning of the complementary parts of the screen slab and of the mask allowing the joining of these two components of the tube.

 The invention also relates to screen slabs and masks specially designed to allow the automation of the assembly and disassembly operations described above. To this end, the screen slabs comprise at least three studs projecting from the lateral part of their internal face and the masks comprise at least three leaf springs provided with an orifice capable of receiving said stud while maintaining play when the blade- spring is in place and at least one part formed with a notch, a tooth, a notch or the like in or on which part can engage said end of a slide to fold said leaf spring inward and pull the mask out of the screen slab during the disassembly of these two components of the tube.

'The invention will appear more clearly with the aid of the description which follows, made with reference to the appended drawings illustrating by way of example an embodiment of the method, of the machine and of the particular devices equipping the screen panel. and the mask of a color television tube. In these drawings
FIG. 1 shows in schematic perspective view with partial cutaway and some exploded parts, the whole of a machine according to the invention,
FIG. 2 schematically shows in top view how a first pre-centering operation of the screen slab of a tube placed on the support frame of a machine is carried out,
FIG. 3 shows in perspective view on a larger scale the connecting parts of the screen slab and of the mask in the cooperation position,
FIG. 4 shows in perspective view a part of the tool ready to reengage under the screen panel in order to ensure the automatic disassembly of the mask and the panel,
FIG. 5 shows in perspective view the position of the tool when the latter engages under the mask,
FIG. 6 is a view similar to that of FIG. 5 showing the relative positions of the parts after actuation of the tool which has caused the start of disassembly between mask and screen slab,
FIG. 7 is a sectional diagram made with partial cutaway substantially in the plane VII-VII of FIG. 4,
FIGS. 8 to 12 show various alternative embodiments of a leaf spring that can be used in accordance with the invention,
FIG. 13 shows in section and with cutaway the tool of the machine supporting a mask before its assembly in a screen slab already in place on the support frame of the machine,
FIG. 14 is a view similar to that of FIG. 6 but made an instant later when the mask is in place in the screen panel,
- Figure 15 shows on a smaller scale in perspective view a positioning that can be used for the mounting pads of the screen slab ,.

FIG. 16 is an exploded perspective view showing an essential part of the tool advantageously used according to a preferred variant of implementation,
FIG. 17 shows in side section like FIG. 3 the connecting parts of the screen slab and of the mask when the mask is in place in the screen slab,
- Figures 18, 19 and 20 show schematically in section the respective positions of the various parts of a tool as illustrated in Figure 16, positions marked relative to the plane of the end of a mask fixing blade engaged on a cooperating stud a screen panel.

We will first describe all the parts of the machine with particular reference to the figure.

The machine comprises an upper support frame 1 capable of receiving the screen panel 2 of a color television tube (FIG. 13) in which the shadow mask 3 may or may not be mounted. The upper support frame 1 itself rests on a lower support frame 4 secured to the fixed frame 5 of the machine Means such as, for example, rolling balls 6 ′ (FIG. 13) allow the upper frame 1 to de-orient both in rotation and in translation relative to the fixed frame of the machine, these movement movements being limited by any appropriate means (not shown) such as cooperating stops provided on the frames 1 and 4. Braking means for these movements such as, for example, bearings or friction rings are also advantageously provided to avoid untimely displacements of the support frame '1.-.

The machine also comprises a tool 6 capable of being raised or lowered, for example by a jack, the piston of which has only been shown in 7 diagrammatically. The piston 7 supports a plate 8 which has fixed supports 9, for example four in the example illustrated. These supports being able to receive the frame 10 (FIG. 14) of the mask 3, of which the pierced surface of the multitude of windows has been identified in 11 for the passage of cathode beams which will excite the phosphors of the various colors.

 In the example illustrated in FIG. 1, the plate 8 also supports four carriages 12 which are capable, as indicated by the double arrows F in strong lines, of moving from the inside towards the outside (from the central axis 13 ′ 8) and vice versa. Any means known per se can be used to achieve these double movement movements. For example, hydraulic or electric cylinders can provide these movements.

Advantageously, the carriages 12 may also have a slight transverse movement of movement parallel to the plate 8 and in a direction perpendicular to the direction of double displacement F. These small movements of movement have been shown by the double arrows in thin lines G. Means such as those which will be illustrated and described on the occasion of FIG. 16 may allow such travel.

 Also, individual means can be provided for raising and lowering each carriage 12 as indicated by the double arrows H and which can be superimposed on the movement. set of lifting and lowering of the plate 8 carrying the four tools.

 We will now describe with particular reference to Figures 4 and 7 the constitution of a carriage 12 essential member of the tool 6, produced according to a first variant.

 According to the example illustrated, the carriage 12 comprises a plate 13 on which slides a slide 14 allowing movement towards the outside or inside (relative to the axis 13, FIG. 1) according to the double arrow indicated F of the slide 14 on the plate 13. This movement is, for example, controlled by a double-acting hydraulic cylinder of which only the supply has been shown at 16 and is guided on two guide rods 17 fixed to the plate 13, as can be understood from the comparison Figures 4 and 6.

 For the movement in vertical movement of the carriages, this can be ensured only by the piston 7 which lifts the plate 8 and therefore the four carriages carried by this plate. Alternatively, one can provide an individual lifting movement of each plate 13 relative to the plate 8 by any suitable means such as for example a hydraulic cylinder for each carriage and appropriate vertical guide means. Such means will not be described because they are of obvious construction for any technician and therefore do not strictly speaking in themselves part of the invention.

 A part 18 in the form of a cam and a part 19 in the form of a hook folded or bent upwards protrudes above the slide 14.

In the embodiment illustrated in the drawings, the part 19 is constituted by an insert in the slide 14 comprising a base 19a fixed by two screws to the slide 14 and a strip 19b protruding upwardly bent in a hook at its end 19c.

 As can be seen more clearly in FIGS. 4 and 7, the cam-shaped part 18 has a recess 21 between two bosses 22 and 23 and it is fixed to its base, for example by a screw 24 in the plate 13 of the carriage 12. In its lower fixing part, the cam 18 is mounted flexibly, for example by means of a flexible part or spring 25 which can form only one piece with the cam 18 or be attached as in the example embodiment illustrated, a screw 26 then ensuring the connection between the leaf spring 25 and the cam 18. Such an assembly ensures the flexible articulation of the cam 18 allowing a movement of movement as shown schematically by the double arrow 26. A tongue 27 which moves in a guide groove 28 formed on the upper face of the slide 14, which tongue is integral with the cam 18 allows the correct articulation movement of the cam 18 in the direction of the double arrow 26 in a plane parallel to the movement of movement of slide 14 on plate 13.

 Referring now more particularly to Figure 3, we will describe the cooperating parts ensuring the assembly of the mask and the screen slab.

 To allow the exact assembly and positioning of the mask 3 in the screen slab 2, a certain number of spring blades 29 are fixed, for example welded to the support frame 10 of the mask 73. Usually three or four such spring blades will be used.

 Each blade 29 comprises an orifice 30 which is designed to receive a cooperating projecting part or stud 31 secured to the wall of the screen slab'2. The pads are obviously positioned so as to be able to receive the orifices 30 of the leaf springs 29 of a cooperating mask 3. In the solution illustrated in FIG. 15, four pads 31, identified to distinguish them 31a, 31b, 31c and 31d are arranged respectively and substantially at 3.6, 9 and 12 hours from the screen.

Each blade 29 further comprises a notch 32 towards its free end. Advantageously, as it appears in FIG. 3, the blades 29 have a shape such that when the mask 3 is in place in the screen slab 2, the wall of the blade goes slightly apart towards the outside when one is near the bottom of the screen slab. In other words, the plane of the free end of the blade makes an acute angle with the vertical plane passing through the edge or the upper edge of the blade as shown in Figure 3 This arrangement combined with a tendency to open parallel to the cam 18 allows, as will appear more clearly below, a good introduction of the tool behind the leaf springs 29 even with large manufacturing tolerances for masks and screen tiles
We will now describe the use of the machine allowing the implementation of the invention.

 We will first assume that a mask 3 is assembled in position inside the screen slab 2 with the pads 31 for positioning the screen slab received in the orifices 30 of the leaf springs 29 for positioning the mask 3 (Figure 3). This assembly is then placed, either by hand, or by a robot on the upper support frame 1 of the machine. When this is done, the assembly is centered on the machine.

 As illustrated in FIG. 2, this pre-centering is achieved by means of one or two jacks 35, the ends 36, 37 of which press two sides 38, 39 of the frame, made of assembly in free movement of amplitude limited) of the support frame 1 on the fixed frame 4 (Figures 1 and 13), 'the assembly is moved until two of the side faces 40, 41 of the screen slab 2 placed on the support frame 1 come in abutment against three pads 42, 43 44 fixed relative to the frame of the machine. This positioning in abutment of the frame 2 on the pads 42 to 44 and which corresponds to a correct pre-centering of the screen slab relative to the machine is detected by three feelers 45, 46, 47 adjacent to the stops 42 to 44.

When the three feelers 45 to 47 detect the presence of the screen slab 2, the ends 36, 37 of the jack 35 are controlled in retraction and the next cycle of operation of the machine can begin. Note that the start of the cycle, that is to say the pre-centering of the screen slab on the machine by the jack 35 can be controlled either manually by an operator, in particular if the screens are placed by hand. on the upper frame 1, either automatically if this operation is done by a robot. In this case, it will suffice to provide on the support frame 1 at least one probe which will detect the present dgune screen slab on the frame 1 and will control the start of the machine operating cycle.

The pre-centering of the screen-screen-mask assembly having been carried out, we will now be able to control the installation of the tool 12 which will make it possible to automatically carry out the disassembly of the mask and the screen-screen.

We will now refer more particularly to FIGS. 3 to 7.

 -The tool 12 is controlled in lifting by its piston 7 (Figure 1), each carriage 12 carrying the cam 18 and the hook-shaped part 19 having substantially this cam 18 behind and below the blade 29 opposite the studs 31 and the strip 19b of the part 19 slightly behind the leaf spring 29 between this leaf and the adjacent lateral internal wall of the screen panel 2.

 The lifting movement more particularly illustrated in FIG. 5 continuing, the cam 18 engages behind the leaf spring 29, this operation being facilitated by the elastic tendency (FIG. 7) of the cam to move outwards as illustrated by the arrow 49 and by the slight obliquity in the same direction given to the blade 29 (Figure 3). However, as soon as the cam comes to bear by sliding against the leaf spring 29, it automatically aligns with it and comes to slide substantially parallel to its surface. Simultaneously, the cam 18, at the end of the upward travel of the tool, abuts on the stud 31, behind the leaf spring 29.The stud is automatically housed in the hollow 21 of the cam between the two protrusions 22, 23 , which results in a slight displacement of the whole of the screen slab and of the mask for their perfect centering with 'the tool 6, this slight displacement being authorized by the free movement of the support frame 1 on the frame -support 4 ..

 Obviously; the operation described for one of the cams is carried out simultaneously for the three or four cams cooperating with the three or four studs and the three or four leaf springs of the assembly placed on the machine.

it immediately appears that one can at will either provide a single lifting movement of the tool 6 to achieve this engagement, or four independent and simultaneous movements of the four carriages 12.

The system which has just been described therefore allows the automatic adjustment of the positioning of the screen-mask assembly relative to the working tool allowing wide manufacturing tolerances -
On the other hand, it clearly appears in FIG. 5 that, when the cam 18 is in place behind the support blade 29 while accommodating in its hollow 21 the stud 31 of the screen slab 2, the strip 19b of the part 19 will be exactly opposite 'the notch 32 provided in the support blade 29. This positioning is very precise because the distances separating the cam 18 from the part 19 and that separating' the orifice 30 from the support blade 29 from its notch 32 are also very precise and obviously chosen at the start equal.

 Under these conditions, the next phase of operation of the tool can begin and the slide 14 of each carriage 12 is controlled in translational movement on each plate 13 of the carriage as indicated by arrow 50 (Figure 6). In such a movement, the strip 19b of the part 19 folds the support blade 29 inwards, freeing the orifice 30 of this support blade from the stud 31 secured to the screen slab.

When the studs are thus released, the lowering movement of the carriages 12, -that is to say- of the tool 6, is controlled, the hooks 19c coming into the notches 32 of the support blades 29 and bringing down the mask inside the screen slab without any risk of rubbing any part of the mask or the machine tool inside the screen slab. It will be noted that in this movement, the mask 3 cannot fall because its frame 10 rests on the four supports 9 (FIG. 1) provided at the four corners of the tool 6.

 Reference will now be made more particularly to FIGS. 13 to 15 to describe the reverse operation of assembling a mask inside the screen slab.

 In the preparatory phase illustrated in Figure 13, the tool 6 is released below the rest of the machine.

A mask 3 is first placed on the tool 6, the frame 10 of the mask being placed on the four studs 9 intended to support it. Simultaneously, the carriages 12 supported by the plate 8 of the tool 6 which are in the position of maximum displacement towards the outside engage their cams 18 in contact behind the leaf springs 29 and the slats 19b opposite the notches 32 of the blades 29, in relative positions corresponding to that illustrated in FIG. 5.

A screen slab 2 is then loaded onto the support frame 1 and its pre-centering is carried out under conditions similar to those described for the disassembly operation and in relation to FIG. 2.

 An instant later, the slides 14 of the carriages 12 are retracted in order to fold the spring blades 29 inwards in a position similar to that illustrated in FIG. 6. This operation of folding the leaf springs can be controlled manually. or automatically, for example by detectors 48 for the presence of a mask 3 on the supports 9 after a certain delay time after the mask has been placed in place on the supports 9.

An instant later, the tool 6 is controlled in lifting movement therefore pushing the mask inside the frames 4 and X and inside the screen panel 2. At the end of the lifting movement, the cams 19 abut against the studs 31 of the screen panel, in a relative position similar to that illustrated in FIG. 6. This final lifting movement of the cams can be obtained either by lifting the piston 7 under the tool 6, or alternatively, if the machine is thus equipped by lifting the individual carriages 12. In either case, the shape of the cams 18 ensures that the studs 31 are finally housed in the hollow 21 of the cams between the protrusions 22, 23. This last close movement is done thanks to the flexibility of mounting the cams and also thanks to the fact of the mounting allowing a certain floating of the support frame 1 on which the screen 2 rests thus ensuring the automatic alignment of the screen on 'the tool.

In this position, it then suffices to release the leaf springs 29 by bringing the slides 14 outwardly, so that the orifices 30 of the blades 29 automatically engage on the .p.lOtsx31 with which they have been perfectly aligned.

Preferably, when four leaf springs are used to fix a mask in a screen slab, first release of three leaf springs and then the fourth, for example that of pad 31d (Figure 15) located at twelve o'clock for better engagement of the blades, or even each blade or some of them successively;
The sequence of operations previously described can of course be programmed so that it is done automatically and successively in the desired order.

 Then, the assembly is perfect by subjecting the plate 8 of the machine to micro-vibrations for example by means of an eccentric motor 54 placed on the plate 8 of the machine and which will ensure, as shown in FIG. 14, the vibration of the assembly. screen-mask-screen Thus, screen-mask 3 will find precisely after each disassembly operation the assembly position in the screen screen it occupied before the previous disassembly operation.

t1 should be noted that before the motor 54 is vibrated, the mask frame only rests on the supports 9.

 In FIGS. 8 to 12, a few modifications of conformation which can be given to the leaf springs 29 are illustrated.

 According to the embodiment of FIG. 8, the leaf spring 55 obviously has the orifice 30 for engagement with the stud 31 of the screen, and the lower edge of the blade has a part 55 ′ cut out with the center of curvature the center of the orifice 30, this in view of a more convenient positioning of the blade ".

 In the embodiment illustrated in FIG. 9, the notch 32 is formed with an inwardly folded recess 57.

The end of the blade is inclined at an angle relative to the vertical to facilitate engagement by the cam 18 as explained above, in particular in relation to FIG. 3.

In the variant illustrated in FIG. 10, the notch 32 of a blade 60 has been replaced by a tab 61 in the form of
T folded towards the interior This bracket will allow hooking by a tool for example in the form of a fork which will overlap the pole of the T and whose curved teeth will be able to hang the bar during the disassembly of the mask.

According to the variant illustrated in Figure 11, the spring 58 has instead of the notch 32 a rounded end 59 whose concavity is facing outwards and on which can hook a hook, for example with a round section for ensure the folding of the leaf spring inwards and the removal of the mask downwards for the disassembly of the mask mounted in a screen slab. Like the blade 56 of FIG. 9, the end plane of this blade has an angle inclination relative to the vertical.

 According to the variant embodiment illustrated in FIG. 12, the leaf spring 64 comprises, in place of the notch 32, a notch 6s facing downwards and a lug 66 in the shape of an L folded veri-intérieur-d ' an angle with respect to the general vertical plane of the blade In this embodiment, it is possible to use a hook strip fairly similar to that described in FIG. 4 and which can ensure both the folding of the leaf spring towards the inside and removing the mask down during the disassembly operation.

 A preferred embodiment of the carriages 12 will now be described with reference to FIGS. 16 to 20.

Similarly to what has been described above, each carriage 12 essentially comprises a substantially fixed part called the plate 13 and a movable part 14 called the slide.

The slide 14 is controlled in radial displacement according to the double arrow F for example by means of a rod 67 terminating in a toothed end 68 which meshes with a pinion 69 whose plane of teeth is substantially horizontal. The rotation in one direction or in the other as indicated by the arrow 70 of the pinion 69 causes the control in translation in one direction or the other of the slide 14 on its plate 13 A single pinion 69 disposed substantially in the center of the plate 8 ( see Figure 1) will allow simultaneous translation control in spacing or retraction of the carriages 12 in the directions of arrow.

In the embodiment illustrated in FIG. 16, the sliding movement of the carriage in the direction of translation F is obtained simply by a dovetail guide formed by a tongue 71 projecting under the slide 14 sliding in a corresponding groove 72 of plate 13.

-On the other hand, to allow a slight movement of movement, the interest of which will appear later, of each carriage 12 in a horizontal direction b perpendicular to the direction F of movement of the slide, it is advantageously provided that the plate 13 rests on the plate 8 on which it is positioned by means of two rectilinear rails 73 engaging in two corresponding rectilinear grooves 74 formed in the plate 8 and of length slightly greater than that of the rails 73. Of course, any other equivalent mechanical means leaving a some freedom of movement of the slide 14 in the direction of the double arrow G on the plate S could be used
Similar to what has been described in FIG. 4, the slide 14 of the carriage 12 comprises a part 19 formed at its hook end 19c-. The object of this part is, as has been described above, to cooperate with the blades 29 for fixing the mask frame to the studs 31 of the screen slab to allow automatic operations to disassemble and disassemble the mask in the slab. screen.

 Each carriage 12 also comprises a cam 18 with a hollow part 21 formed between two projecting parts 22, 23. the general function of this cam is similar to that of the cam 18 of the previous embodiment and whose configuration. has been described more particularly with reference to FIG. 7.

In the present embodiment, the cam 18 is however not flexibly articulated as described above. The cam 18 is instead mounted movable in translation relative to the carriage 12 in a movement parallel to the arrow F. Specifically, the cam 18 comprises, in a manner somewhat similar to what has been described in Figure 7, a tongue 27 which moves in a guide groove 28 formed in the slide 14.

At its lower part, the cam 18 comprises a rod 75 which slides in a guide orifice 76 formed in the plate 13 of the frame. Thus, the cam 18 can move in a pure translational movement, without articulation and in a radial direction parallel to the arrow F. A spring 77 is hooked at 78 to the cam 18 and at 79 at a point of the slide 14, this spring tending to permanently maintain the cam 18 applied under pressure against the movable slide 14.

 The operation of the device described above will now be explained with particular reference to FIGS. 17 to 20.

 We will first describe a disassembly operation of a mask 3 put in place in the screen slab 2. -The whole being assumed to be put in place on the machine as described in relation to Figure 2, we order from from a position illustrated in FIG. 18 in which the sliders 14 are spaced radially, the inward approximation of the sliders 14 on a first stroke e1, bringing the carriage into the position illustrated in FIG. 19. The length of the stroke e1 is chosen so that the median plane of the cam 18 substantially coincides with the plane 80 tangent to the outer face of the end of a blade 29 for fixing the mask 3 engaged on a stud 31 of the screen slab. Specifically, in this position illustrated in Figure 19, 'the upper end curved towards the outside of the cam 18 is clearly outside the plane 80, as indicated by the letter a, while the inner face of the cam is slightly inside the plane 80 as indicated by the letter'd, In this way, it is ensured that when the plate 8 of the tool is actuated in lifting, the cam 18 will automatically engage behind and against the end of the leaf spring 29, this movement being further facilitated when this leaf is inclined at an angle to the vertical as illustrated more particularly in FIGS. 3, 9 and 11.

 On the other hand, the free sliding movement in the direction of arrow F of the cam 18 on the carriage is authorized by the mounting, while the spring 77 will keep the cam 18 pressed behind the blade 29. Thus, it is ensured a perfect engagement of the cam 18 behind the blade 29, during the lifting movement of the whole of the plate 8 controlled after displacement of the stroke and of the slide 14.

On the other hand, given the slight movement of movement authorized for the carriage 12 in the perpendicular direction G (FIG. 16), it appears that the hollow part 21 of the cam will automatically center on the stud 31.

 Once these operations have been carried out, the second displacement ′ of a stroke e2 of the slide 14 is then controlled as shown in FIG. 20, which allows the hook 19 to fold the blade 29 inwards and to release it from the stud 31. In this movement , the cam 18 does not move appreciably remaining remaining applied by the spring 77 behind the blade 29 of which only the end is folded and released from the stud 310 From this moment, the lowering movement of the tool retrieving the operating sequence described in relation to the first variant.

We will now describe an assembly operation.

The preliminary operations of placing the mask on the tool and the screen panel on the machine are obviously the same as those described for the first variant.

 After the mask has been placed on the tool, the bucket grouts are controlled in the position illustrated in FIG. 20, after which the tool can be lifted under the screen slab, the cams 18 ensuring the positioning relative correct ment of the mask and the slab by positioning the studs 31 in the recesses 21 of the cams. When this operation is carried out, the slide 14 is moved back on the run e2 bringing the carriage into the position illustrated in FIG. 19, the orifices 30 of the blades 29. automatically engaging on the pads 31. The assembly can be vibrated, after which the tool can be released for a new cycle.

It should be noted that, unlike the first variant, the correct relative positioning of the mask in the screen tile is done by an automatic adjustment of the tool inside the screen tile, and not of the entire screen slab on the tool. * In other words, in the second variant described, the movement movements authorized for each tool both in the direction of the arrows F and in the direction of the arrows G allow adjustment automatic tooth tool in the screen slab, while according to the first variant, we played on the possibility of displacement of the upper frame 1 of the machine on the fixed lower frame 4 to obtain the adjustment of the tool and therefore of the mask by compared to the slab-screen .. 'The advantage is that the tool is much lighter and -that this automatic adjustment is done with less effort and therefore in better conditions of speed and' efficiency
Of course, the invention is in no way limited to the illustrated and described embodiments which have not been given except by way of example, on the contrary comprising all the technical equivalents of the means described and their combinations if these are carried out according to the spirit and set used in the context of the claims which follow.

Claims (13)

1. Method for automating the operations of assembling and disassembling a mask inside the screen panel during the manufacture of a color television tube of the type comprising leaf springs for mounting the mask in the screen which positions the mask in the screen when cS parts of said leaf springs come to cooperate with complementary parts of said screen slab, said method being characterized in that for the disassembly of the mask and the screen slab  - the assembly is positioned on a support frame of an assembly and disassembly machine,  - a pre-centering of the assembly thus positioned on said frame is carried out,  - We come to take it together from below by means of a tool which flexibly engages behind each leaf spring between said leaf and the internal wall of the screen slab to abut at the end of the race against the aforementioned cooperating parts of connection between said blades and said screen slab simultaneously centering said assembly on said tool, - said blades are then retracted inwards, releasing said cooperating parts of said blades and of said screen slab,  - then said mask is lowered under said screen panel,  and for the assembly: - the mask is introduced on 1 tool, the screen panel is positioned on said support frame of the assembly and disassembly machine,  - a pre-centering of the screen slab is carried out on said frame,  - said blades are retracted inwards,  said tool carrying said mask is lifted until it abuts against the aforementioned cooperating connecting parts integral with the screen slab, simultaneously centering the assembly and the tool,  the blades are released outwards until said cooperating connecting parts between said blades and said screen slab cooperate,  - we vibrate 'the whole mask and screen slab,  - and the tool is removed. 2. Method according to claim 1, characterized in that said blades are successively released, and preferably one of them slightly after the others.  a tool capable of going up and down below said support frame, said tool comprising supports for the mask, cam-shaped means for engaging behind said leaf springs said parts integral with the screen slab such as studs, cooperating with said parts, such as openings, said leaf springs, and sliders, one end of which, in bent hook, engages behind each blade and is capable of folding said jame inwards when the slider is controlled in retraction ..  '3. Machine for the automation of the operations of assembling and disassembling a mask inside the screen panel during the manufacture of a color television tube, of the type comprising leaf springs for mounting the mask in the screen which positions the mask in the screen when parts of said leaf springs come to cooperate with complementary parts of said screen panel, a machine in particular for implementing the method of claims 1 or 2, characterized in that that it includes - a support frame capable of supporting the screen-slab of a tube while leaving free access under the interior volume of the screen slab,  4. Machine according to claim 3, characterized in that the tool comprises as many cams and slides as the masks comprise said leaf springs.  5. Machine according to claim 3 or claim 4, characterized in that said cams are mounted free in translation parallel to the movement of movement of the slides and are resiliently biased to be applied against said slides.  6. Machine according to claim 3 or claim 4, characterized in that said cams are mounted flexibly hinged on said tool tending to take an inclination inward while flaring from the bottom up when said cams are engaged by below behind said leaf springs against which they come to bear.  7. Machine according to one of claims 3 to 6, characterized in that said tool comprises a plate capable of going up or down under said support frame, which plate carries said supports, said cams and said slides.  8. Machine according to one of claims 3 to 7, characterized in that said slides are mounted on carriages capable of moving radially relative to the vertical central axis of the machine and have a slight movement of horizontal movement in a direction perpendicular to this radial displacement.  9. Machine according to one of claims 3 to 8, characterized in that it comprises automatic means of centering by jacks of the screen slab on said support frame  10. Machine according to one of claims 3 to 9, characterized in that it comprises means for detecting the placement of the screen slab and / or the mask, which detection means control the start of the following cycle. machine operation '.  11. Machine according to one of claims3 to 10, characterized in that said support frame is mounted in limited free movement on an underlying frame integral with the frame of the machine, by means such as ball bearings and / or support pads.  12. Screen plates and masks for automating the operations of assembling and disassembling a mask inside the screen plate during the manufacture of a color television tube, of the type comprising leaf springs for mounting the mask in the screen which position the mask in the screen when parts of said leaf springs come to cooperate with complementary parts of said screen slab, for implementing the method according to claims 1 or 2 and usable with a machine according to one of claims 3 to 11, characterized in that the screen slabs comprise at least three studs projecting from the side wall of their internal face and in that the masks comprise at least three leaf springs provided with an orifice capable of receiving said stud while keeping it there without play when the leaf spring is in place, and at least one part formed with a notch, a tooth, a notch or the like in or on which part p oura engage said end of a slide to fold the leaf-spring inward and pull the mask out of the screen slab during disassembly of these two components of the tube. 13 Mask according to claim 12, characterized in that said leaf springs have a shape such that when the mask is in place in the screen slab, they slightly move away towards the outside when approaching the bottom of the screen.