Note: Descriptions are shown in the official language in which they were submitted.
1 156304
1 -1- RCA 74,211
AUTOMATIC MASK-FRAME INSERTER
This invention relates to an apparatus for
5 automatically inserting mas~-frame assemblies into faceplate
panels of cathode ray tubes.
The desirability of automatically inserting a
cathode ray tube shadow mask-frame assembly into a previously
matched faceplate panel has been long appreciated within
10 the cathode ray tube industry. Until the present invention,
several factors have prevented prior art attempts to
develop automatic insertion apparatuses from being suacessful.
The primary factor is that each faceplate panel-mask-frame
assembly varies to an appreciable extent from other such
15 assemblies. The main reason for this variation is that
close tolerances cannot be held in manufacturing the glass
faceplate panel. Because of this, each mask-frame assembly
is unique. Prior art apparatuses have been unable to adapt
to such uniqueness. The present invention, however, provides
20 an apparatus which can adjust to account for the variations
in mask-frame assemblies and faceplate panels.
In accordance with the invention, an automatic
apparatus is provided for inserting
a mask assembly into a cathode ray tube faceplate panel.
26 The mask assembly includes an apertured shadow mask having
at least three springs attached thereto with each spring
including an aperture. The faceplate panel includes a
viewing faceplate portion and a peripheral sidewall
including at least three studs embedded therein for
30 engagement with the spring apertures. The automatic
apparatus includes a subassembly at each mask spring
location. At least three subassemblies are movable
peripherally with respect to a mask mounted on the apparatus
and include a stop for contacting the lower edge of a mask
3S spring. Each movable subassembly also includes a locator
pin movable between an engaged position and a disengaged
position. The locator pin, when in an engaged position, is
.
spaced ~rom the stop a predetermined spacing equal to a
standard spacing between a lower edge of a spring and the
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1 -2- RCA 74,211
centerline of the spring aperture plus a predetermined
lifting distance. Each movable subassembly further includes
a fork-sh~ped member or stud finder centered with the
5 location pins.
In the drawings:
FIGURE 1 (Sheet 1) is a sectional side view of a
cathode ray tube faceplate panel with a shadow mask-frame
assembly mounted therein.
FIGURE 2 (Sheet 1) is a back view of the faceplate
panel taken at line 2-2 of FIGURE 1.
FIGURES 3 and 4 (Sheet 2) and 5 (Sheet 1) are side,
front and top views, respectively, of an automatic mask
inserter according to the invention.
FIGURES 6 and 7 (Sheet 3) are top and front views,
respectively, of a mask locator assembly portion of the mask
inserter of FIGURES 3, 4 and 5.
FIGURE 8 (Sheet 3) is a partial sectional view of
the mask locator assembly taken at lines 8-8 of FIGURE 6.
FIGURES 9 and 10 (Sheet 4) are top and front views,
respectively, of a movable pin locating assembly portion of
the mask locator assembly of FIGURES 6 and 7.
FIGURE 11 (Sheet 5) is a side view of a mask
locking assembly portion of the mask inserter of FIGURES 3,
25 4 and 5-
FIGURE 12 (Sheet 5) is a bottom ~iew of the mask
locking assembly taken at lines 12-12 of FIGURE 11.
FIGURE 13 (Sheet 5) is a sectional view of the mask
locking assembly taken at lines 13-13 of FIGURE 12.
FIGURES 14, 15 and 16 (Sheet 6) are top, front and
side views, respectively, of a faceplate panel locator
assembly.
FIGU~ES 1 and 2 show a mask-frame asse~bly 10
mounted within a cathode ray tube faceplate panel 12. The
35 mask-frame assembly 10 includes a domed thin metal apertured
shadow mask 14 attached peripherally to-an L-shaped rein-
forcing frame 16. Four springs 18 are attached to the frame
16. Apertures in these springs 18 engage four metal studs 20
which are embedded in a sidewall 22 of the faceplate panel 12.
An apparatus embodying the present invention is used
to insert a mask assembly or a mask-frame assembly into the
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1 156304
1 -3- RCA 74,211
faceplate panel 12. The apparatus includes a subassembly
at each mask-frame spring location. Three of these
subassemblies are movable peripherally with respect-to a
5 mask mounted on the apparatus and include: (1) a stop for
contacting the lower edge of spring, (2) a locator pin
movable between an engaged position and a disengaged
position,and (3) a fork-shaped stud finder centered with the
locator pin. The fourth subassembly does not require
10 compensating features since its only purpose is to
participate in the compression of the spring at its
location when the mask-frame assembly is being inserted
into the faceplate panel. Since all four springs are
previously welded to the frame during a procedure called
16 "Q"-set, if three of the springs are located and fixed
by the apparatus, then the location of the fourth will also
be fixed.
The mask inserter 30 shown in FIGURES 3, 4 and
5 comprises five mechanical subunits: a mask post assembly
~0 32, a mask locator assembly 34, a panel locator assembly 36,
a bearing plate assembly 38,and a drive assembly 40. The
major components of each of these subunits and the relation
of the subunits to each other will be presented below along
with a description of the operation of the mask inserter 30.
26 Operation of the mask inserter 30 begins by loading
a mask-frame assembly onto four locating nests 50 positioned
at the top of the mask in~erter 30. These nests 50 roughly
locate the mask-frame assembly in relation to three spring
hole locating pins described below. The weight of the mask-
30 frame assembly activates a sensor 54 located near one of the
locating nests. The sensor causes an air cylinder 56 to
lower the mask post assembly unit 32. As the mask post
assembly unit 32 is lowered, a mask-frame assembly, resting
on the locating nests50, is also lo~ered until the four
35 support springs welded to the frame come into contact with
four stops 58 located on three movable pin locating
assemblies 60 of the mask locator assembly 3~ as shown in
FIGURES 6, 7, 9 and 10. This is the first in a series of
steps to establish reference points and to maintain them in
40 their correct location. The location of the stud hole in
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1156304
1 -4- RCA 74,211
the spring is reasonably accurately located in relation to
the edge of the spring. By causing the spring edge to rest
on a known surface, e.g. the stop 58, the center line of
5 the spring hole is closely established.
After the springs have contacted the stops 58,
bringing the mask frame assembly to rest, the mask post
assembly 32 continues its downward motion causing a cam 62,
mounted thereon and shown in FIGURE 4, to come into contact
10 with a cam follower 64 on the lower end of a locating pin
actuating link 140. During this further downward travel of
the mask post assembly unit, the second step in the locating
series is taken.
At the moment the mask support springs come into
15 contact with the fixed stops 58, a pivot link 66 is in a
position indicated by 'A' in FIGURE 10. As the mask post
assembly 32 moves downward bringing thé cam surface 62 into
contact with the cam follower 64, a locating pin 70, held
in the upper end of the pivot link 66, enters into the spring
20 aperture, as shown in position 'B' of FIGURE 10. Because the
dimension from the edge of the spring to the center of the
hole is held to a reasonably close tolerance, by holding
some corresponding greater distance between the surface of
the stop and the center line of the locating pin 70, the
25 pin 70 and spring hole are in known relationship to each
other. Thus,the mask-frame assembly will be elevated a
predetermined distance in the vertical plane after the pin 70
has been inserted into the spring aperture. ~owever, due to
the difficulties in holding the metal and glass subassemblies
30 to a close tolerance,there is still no assurance that the
pin and spring hole are aligned in the horizontal plane.
In order to assure correct placement o~ the mask-
frame assembly within the panel, it is essential that the
spring hole be held in such a manner as to be centered with
35 the panel stud when the two are brought together. As shown
in FIGURES 9 and 10, the locating pin 70 is accurately
located in relation to a fork shaped member 72. These two
components share the same centerline by being designed and
built as intregal parts of the same subassembly. While
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l 156304
1 -5- RCA 74,211
the pin pivot link 66 is moving the locating pin 70 into posi-
tion and elevating the mask-frame assembly approximately one
thirty-second (1/32) inch (or 0.8mm) into position,the pin70 is
5 see~ing the centerline of the spring hole in the horizontal
plane. This is accomplished by mounting the entire pin
locating assembly 60 on movable slides 76,which are free to
move in a horizontal plane (peripherally with respect to
a mask assembly mounted on the apparatus) while the contoured
10 tip of the pin 70 seeks and enters the spring hole. The
engaged position of the pin pivot link 66 with the pin 70 in
a spring hole is shown as position 'B' in FIGURE 10. At
this point, the mask-frame assembly has been captured and
the spring holes are accurately located vertically despite
15 all variations within the mask frame assembly. Since the
mask-frame assembly is a welded unit, it is precisely aligned
vertically for final insertion into the faceplate panel.
While the pin-hole search action has been taking
20 place, the mask post assembly 32 has continued its downward
movement until it contacts a switch 78 at the bottom of the
stroke of the air cylinder 56 as shown in FIGURES 3 and 4.
Activation of the switch 78 enables the inserter control
systems to proceed to the next operation. A faceplate panel
26 is loaded onto guides 80 and 81 at the top of the inserter
30, as shown in FIGURES 3, 4 and 5. These guides 80 and 81
roughly locate the faceplate panel in relation to the support
springs previously located within the apparatus. When the
faceplate panel is placed on the guides 80 and 81 it contacts
30 a sensor 82, shown in FIGURE 5. A signal from the sensor 82
prepares the unit to be triggered to complete its cycle, as
is done by the operator depressing two start switches(not shown).
When the operator despresses the switches, an electric motor
84 starts to turn a main cam shaft 86, shown in FIGURES 8
35 and 11. This shaft rotates a series of cams which are so
keyed together as to preserve timing integrity.
As explained above, the mask-frame assembly
has been positively located into a vertically true position.
It is now necessary to take action to preserve this
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11~6304
1 -6- RCA 74,211
condition while preparing the apparatus to accomplish the
actual insertion of the mask-frame assembly into the
faceplate panel.
The first action caused by the cam rotation is to
bring th~o frame locking spools 88, 90, 92 and 94, shown in
FIGURES 11 and 12, into contact with the inside corners of
the frame. The four locking spools 88, 90, 92 and 94 are
driven sequentially into the four corners of the frame by an
10 air cylinder 98. Two spools 88 and 90 are spring
loaded by springs 100 and 102 to accept frame inner contour
variations as shown in FIGURE 12. As a cam 96 is rotated,
spring loaded frame locking spools 88 and 90 are driven
outwardly by air cylinder 98,thus exerting pressure
15 diagonally on opposite corners of the frame. ~s the cam 96
continues its rotation, non-spring ~ed spools 92 and 94
are driven into the remaining two diagonally opposite corners.
The placement of these four spools securely locks the mask-
frame assembly into its correct horizontal and vertical
20 orientation.
The next action is to fix the fork-shaped
~ember 72, shown in FIGURES 9 and 10, in position. As noted
above, these members or stud locators 72 are integral with
the spring hole locating pins70. Since the pins 70 are
25 seated in the spring holes and the pin and stud locators are
exactly aligned, it is necessary to lock this condition in
place. As cam 96, shown in FIGURES 12 and 13, continues its
cycle, it triggers an air switch 104, shown in FIGURE 12.
This air switch 104 activates air cylinders 106, shown in
30 FIGURE 7. This action drives the rod end of the air
cylinders 106 against the under side of the movable slide
assem~ly 76,1Ocking the entire slide system in place.
Next, it is necessary to compress the frame springs
in order to clear the panel studs during the insertion action
35 and to also remove the locating pins 70 from the spring holes.
As the main cam shaft B6 rotates, a spring compressor
activating cam 108, shown in ~IGURES 6 and 8, moves against
a cam follower 110, shown in FIGURE 6. The follower 110 is
affixed to an L-shaped linkage rod 112 pivoting about a
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1 -7- RCA 74,211
center 114. Attached to the end of the linkage rod 112
is an intermediate cam 116, shown in FIGURE 8. Attached
to this cam 116 are three linkage systems 118, 120 and 122.
5 A fourth compression linkage 124 is connected to the L-shaped
linkage rod 112. As the cam shaft 86 drives the cam 108,
the entire spring compression system of the four
interconnected linkages 118, 120, 122 and 124 is driven
as a unit to pull the frame springs inward toward the frame,
10 freeing them from the locating pins 70 and holding the
springs in pl'ace to clear the studs upon insertion of the
mask-frame assembly into the faceplate panel. The cam
shaft 86 rotates a riser cam 126, shown in FIGURES 3, 4 and
11, riding against a cam follower 128, shown in FIGURE 4.
15 The cam follower 128 is attached to a bracket 130,which in
turn is secured to an intermediate fixed plate 132 which is
part of the bearing plate assembly 38. As the riser cam
1~6 tu~ns against the cam follower 128,it is caused to rise
by its contour surface. This raises the mask-frame holding
20 assembly of FIGURES 6 and 7. The vertical motion of this
aSsembly causes the spring hole locating pins 70 to be
withdrawn from the springs and placed in a free attitude as
shown at 'C' in FIGURE 10.
As the mask-frame holding assembly moves into the
25 faceplate panel, action must be taken to insure that the
' faceplate panel is free to be moved into proper orientation
with the incoming mask-frame assembly. As noted above,
the faceplate panel was placed within the guides
80 and 81 with the seal land facing down. The guides 80
30 and 81 are set to provide only enough clearance to accept
the largest specified faceplate panel criteria. However,
due to manufacturing inaccuracies which cause wide variations
in individual tolerances, placement of the studs is not
exactly the same in every faceplate panel. Thus,when the
36 support springs are welded to the frame using the panel as
a locating jig, the resulting assemblies are not uniform.
In order to overcome this difficulty and to,allow the panel
to be moved into its proper orientation, it is necessary to
remove the restriction set ~y the guides 80 and 81 used to
` 1156304
1 -8- RCA 74,211
originally locate the panel when it was loaded. As the
mask-frame holding assembly moves upward, an air switch
(not shown) is activated. This activates an air cylinder
5 134, shown in FIGURE 15, causing the interconnecting linkages
136 to move. The ends of these linkages 136 are attached to
the lower ends of the guides 80 which are free to rotate
about their centers. As the linkages move they cause the
guides 80 to rotate a sufficient amount so as to present
10 a flat portion of the guides 80 to the panel. Presence of
these flat portions reduces the outer diameter of the guides
80 by a substantial localized amount. This amount of extra
movement is now available to permit movement of the panel.
While the panel guides 80 are being rotated, the
15 upward motion of the mask-frame holding assembly is
proceeding. As the assembly enters the panel, the fork-
shaped stud locators 72 enter the panel at the areas of the
studs. Because of the V-shape of the inside of the stud
locators72, they have the capability of finding their
20 respective stud even though they are not aligned. The stud
locators 72 thus capture the studs and,due to the freedom
given to the faceplate panel by rotating the panel guides 80,
the panel is free to move into correct alignment. The panel
is raised off the pads and is supported only by the studs
25 resting in the V-shaped locators 72. At this time, the
following conditions prevail. The panel is securely held
by the primary locating points, the studs. It is held in
true alignment and orientation with the mask-frame assembly,
since all variables which have entered the assemblies during
30 fabrication have been provided for by permitting the spring
hole locating pins 70 to move into position to compensate
for any errors in frame spring location and by permitting
the faceplate panel to be moved into correct alignment with
the mask-frame assembly.
Now that the mask-frame assembly has been brought
into proper orientation with the faceplate panel, provisions
are made to attach the mask-frame assembly onto the faceplate
panel. As the main cam shaft 86 continues its rotation, the
spring compressing cam 108 is broughtto its opposite
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1 15830~
1 -9- RCA 74,211
lobes, actuating intermediate cam 116 and permitting the
spring compressor linkages 118, 120, 122 and 124 to release
the springs to their normal inserted positions. This action
5 places the support springs correctly on the panel studs,
completing the mask-frame assembly insertion operation.
Following the insertion operation, it is necessary
to prepare the unit for the next loading sequence. Further
rotation of the cam shaft 86 brings the high lobe of the cam
10 96 into contact with a roller 138 which brings the frame
locking spools 88, 90, 92 and 94 inward to the center of the
unit. Continued rotation of the cam shaft 86 releases the
air switch 104,releasing the saddle clamping air cylinders
106. Continued rotation of the cam 96 lowers the mask
15 locator assembly 34 below the level of the mask-frame
insertion. At this time, the spring compressors and stud
Iocators 72 are open to their mask load position. The
mask-frame locator assembly 34 is then returned to its lower
position by further rotation on the cam 96. The final few
20 degrees of cam shaft rotation brings the cut-off lobe of the
cam 96 into position to stop the electric motor 84 and at
the same time activate an air switch (not shown) to cause
the piston rod of the air cylinder 56 to raise. This action
raises the mask post assembly 32 into its upper position
25 placing the mask-frame locating nest at its load position.
At this point, the completed mask-frame-panel assembly can
be removed either by manual or mechanical means. The
apparatus is now ready to receive the next mask-frame assembly
and repeat the operation of inserting the assembly into a
30 faceplate panel.
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