Apparatus for assembling a shadow mask and panel of a picture tube of a television receiver

An apparatus for assembling a shadow mask and panel of a picture tube of a television receiver, said mask and panel being provided with fixing members engaging each other in a fixed relative position of the mask and panel. The apparatus is provided with separate supports for the mask and panel, one of said supports being made as a floating plate movable relative to the other fixed support parallel to its plane and also perpendicularly to said plane and, in addition, rotatable around an axis perpendicular to said plane. The floating plate is connected to mechanical means for moving the plate relative to the fixed support. In this way, the mask and panel may be positioned only roughly in register on the apparatus, whereby mechanical moving of the floating plate brings the mask and panel in such a relative position that their fixing members automatically engage each other.

The present invention relates to an apparatus for assembling a shadow mask 
and panel of a picture tube of a television receiver, said mask and panel 
being provided with fixing members engaging each other in a fixed relative 
position of said mask and panel, said apparatus comprising separate 
supports for said mask and panel, said supports being adjustable in 
relation to each other. 
In connection with the manufacture of colour television picture tubes, the 
mask and panel already arranged in pairs must be disassembled and again 
assembled several times during the various manufacturing steps. 
Earlier, this assembling step has been carried out manually. 
In the automatization of the assembling step, dimensional variations of the 
mask and panel have presented a problem. Especially the position of the 
fixing members interconnecting the parts varies with the result that into 
a specific panel will fit only a mask originally arranged therein. 
The construction of a device for assembling the mask and the panel is also 
limited by the fact that only relatively small external forces may be 
applied to the mask. 
It is the object of the present invention to provide an apparatus following 
an automatization of the assembly of both associated parts. This object is 
achieved by means of an apparatus according to the invention, said 
apparatus being characterized in that one of said supports is made as a 
floating plate movable relative to the other support parallel to its plane 
and in the direction of an axis transverse to said plane and rotatable 
around said axis, and that said apparatus is provided with operating means 
connected to said floating plate to bring said plate mechanically in said 
motion. 
The apparatus according to the invention does not even try to guide the 
parts immediately exactly in register with each other, but the parts are 
first placed roughly in register, whereafter the correct position is 
scanned by moving the parts in relation to each other.

In FIG. 1, there is shown a panel 1 for a picture tube in a television 
receiver, and FIG. 2 shows a mask, said mask and panel being connected 
together by means of conical pins 3 in the inner surface of the panel and 
by means of leaf springs 4 in the mask frame. The assembling is carried 
out by pressing the springs inwardly (in the direction of the arrows) and 
by placing the mask into the panel into its proper location and by 
releasing the springs, whereby the bias outwardly against the conical 
pins. The conical pins hit holes 5 in the springs, thereby interlocking 
the mask and panel without any clearance. 
The apparatus according to the invention comprises a frame consisting of an 
upper horizontal collar plate 6 and a lower bottom plate 7 connected to 
each other with four rods 8. Guides 9 are attached to four corners in the 
collar plate for centering the panel 1 into a desired position on the 
collar plate. The collar plate thus forms a fixed support for the panel. 
The apparatus further includes a movable support consisting of a horizontal 
plate 10 mounted "floatably" between ball rolls 11 attached to the collar 
plate and said rods and arranged at each corner of the collar plate. The 
plate is thus able to move vertically within the limits defined by the 
ball rolls, as shown by arrow A in FIG. 3. The movements of the plate in 
the horizontal plane shown by arrow B are limited by pins 12 journalled 
vertically slidably in the plate and extending into corresponding holes 13 
in the collar plate, as shown in more detail in FIG. 6. The extent of the 
horizontal movement is determined by the difference between the pin 
diameter and the hole diameter. The conical portion 12a of the pin 12 also 
serves as a centering means. The pin is movable vertically by means of a 
pneumatic cylinder 14 supported by the plate 10. The plate is thus able to 
rotate to a limited extent also in its own plane, as shown by arrow C. 
Guides 15 for the mask 2 are attached to the upper surface of the plate in 
the corners thereof. Of said guides, three are provided with locking arms 
16 displaced by means of pneumatic cylinders 17 supported by the plate 10. 
Centrally in the apparatus, there is mounted a vertical rocking shaft 18 
extending through a central hole 19 in the plate, said plate being 
attached to a flange in the upper end of said shaft by means of tension 
springs 21. The rocking shaft is mounted rotatably and vertically slidably 
in a bearing bracket 22 supported by the bottom plate 7 of the frame. A 
gear motor 23 supported by the bottom plate is via a crank 24 and an arm 
25 and a bracket 26 connected to the drive shaft 18. Another gear motor 27 
supported by the bottom plate is in turn connected via a crank 28 and an 
arm 29 to an arm 30 attached to the lower end of the rocking shaft. The 
arrangement is such that the rotary motion of the gear motor 23 causes a 
vertical reciprocating movement of the rocking shaft in the bearing 
bracket, while the rotary motion of the gear motor 27 produces a 
reciprocating rotation of the rocking shaft in the bearing bracket around 
its axis. 
The movable plate 10 is vertically supported by springs 31. 
Between the movable plate 10 and the bottom plate 7 there is mounted an 
intermediate plate 32 (FIG. 5) to the upper surface of which four grippers 
33 are fastened, said grippers being moved by pneumatic cylinders 34. The 
gripper halfs are pivoted in relation to each other and to the 
intermediate plate by means of a pivot 35, and a spring 36 between the 
gripper halfs pushes the halfs apart. The intermediate plate is mounted 
vertically movably on guides 37. A pneumatic cylinder 38 is mounted on the 
intermediate plate and connected via an arm 39 to a shaft 40 both ends of 
which are connected via arms 41 and 42 to the guides 37. 
The apparatus operates as follows: 
In the initial position of the apparatus, the centering pins 12 are pushed 
upwardly, i.e. the floating plate 10 is centered and supported by the 
lowermost ball rolls 11. The locking arms 16 in the guides 15 of the 
floating plate are located in the open position. The intermediate plate 32 
and the grippers 33 are located in the upper position and are opened. The 
mask 2 is positioned on the guides 15. The locking arms in the three 
guides are closed. The grippers close and press the leaf springs 4 in the 
mask towards the sides of the mask (FIG. 7). Next, the panel 1 is 
positioned on the guides 9 of the collar plate 6. Then, the centering is 
released, i.e. the pins 12 are displaced to their lower position. 
Thereafter the grippers 33 are released as the piston rod of the cylinder 
34 is freely pushed out. Each gripper is opened by means of the return 
spring 36 and, of course, the spring 4 of the mask. The grippers 33 are 
retracted along with the intermediate plate to their lower position by 
means of the cylinder 38. 
Now the springs 4 of the mask are resting tensioned against the conical 
pins 3 of the panel 1. If the position of the mask and panel is correct, 
the interlocking will take place immediately. However, this happens very 
seldom wherefore a scanning motion is always carried out. The rocking 
shaft 18 reciprocates up and down by means of the gear motor 23, the crank 
24, the arm 25 and the bracket 26 and, at the same time, turns slower (or 
faster) to and fro by means of the gear motor 27, the crank 28, the arm 29 
and the arm 30, moving thereby by means of the springs 21 the floating 
plate 10 and the mask located thereto. Thus, the apertured leaf spring 4 
of the mask moves in an up-and-down direction relative to the assumed 
location of the conical pin and, at the same time, reciprocates slowly 
horizontally, i.e. scans a sufficiently big area so that the pivot 3 is 
forced to hit the hole 5 in spite of dimensional variations of the parts. 
Because the scanning motion is transmitted by means of the springs, the 
driving means 25-30 for the scanning motion may continue to run even after 
the locking has taken place, and too great forces are not applied to the 
mask even then. 
When the driving means for the scanning motion have stopped, the locking 
arm 16 of the mask are opened and a robot lifts the mask/panel combination 
upon a conveyor. The apparatus is returned to its initial position, 
whereby it is ready for a new working cycle. The apparatus may be 
controlled either by control means of its own or by the control means of 
the robot. 
The drawings and the appended specification are only intended to illustrate 
the idea of the invention. In its details, the apparatus according to the 
invention may vary considerably within the scope of the claims. Thus, the 
scanning motions of the floating plate described above may, instead of the 
two driving means shown, by operated by means of a single driving means. 
Likewise, other means, for example, electric, hydraulic and similar means, 
may be used instead of the air cylinders described above. 
If the positions of the conical pin of the panel and of the leaf spring of 
the mask varies in the vertical direction to such an extent that the 
scanning motion cannot be extended sufficiently, it is possible to use an 
apparatus which automatically corrects the relative position of the mask 
and panel in the vertical direction. For example, the panel may be 
displaced in the vertical direction. The impulse for the correction may be 
taken by sensing the difference in height of the pin and the leaf spring. 
A satisfactory result is obtained by sensing the difference in height only 
between the apparatus frame and the pin.