Note: Descriptions are shown in the official language in which they were submitted.
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The present invention relat~s to an apparatus and
method for automatically mounting window glasses on the front
and rear windows of an automobile body.
In known apparatus of this kind, for example, as
described in Japanese Laid-Open Patent application No.
36770/1983, a jig for holding the window glass is supported
on a support frame so that it can be moved back and forth on
the support frame. The support frame is mounted on a robot.
The robot positions the support frame at a location facing
the window of an automobile body on the assembly line and,
with the support frame held in this position, the jig is
advanced toward the window to mount the window glass unit.
In this apparatus, the robot, which is mounted on the ceiling
above the assembly line, and which is movable lengthwise and
widthwise of the car body, has an arm consisting of
vertically swingable parallel links with the above-mentioned
support frame attached to the lower end thereof.
The positioning of the window glass by this robot
is performed as follows. Outside the conveyor line, the
window glass is set in the jig. ~hen the robot is shifted
toward the conveyor line and, according to signals from
various detectors attached to the support frame that detect a
car body position in terms of the three directions along the
length, width and height thereof, the support frame is movecl
in parallel with these three directions so as to be
positioned at a location facing the window of the car body.
The window glass mounting apparatus mentioned
above, however, has a drawback. Since the robot is suspended
above the car body conveyor line, it is necessary to carry
the car body on a conveyor running on the floor in order to
avoid interference with the robot. This puts constraints on
the design of an automobile assembly line. For example, the
problem arises that it is not possible to adopt an assembly
line in which the car body is carried by a hanger conveyor
enabling both the mounting of the window glass and the
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assembly work associated with the under body components to be
performed on the same assem~ly line.
Even with the above window glass mounting
apparatus, it is possible to use a hanger conveyor to carry
the car body if it is so arranged as to have the robot
provided with a robot arm which is swingable from outside the
car body conveyor line toward the line. In this arrangement,
the robot arm is provided at the front end with the support
frame. With the arm turned away from the conveyor line, the
window glass is set in the jig and thereafter the arm is
turned back toward the conveyor line to mount the window
glass. This arrangement allows the robot to be positioned
outside the conveyor line, which in turn permits the use of
the hanger conveyor for conveying the car body.
With this arrangement, however, the weight of the
support frame and jig at the front end of the robot arm
causes the arm to droop forwardly downward, making it
impossible for the window glass to be mounted at the correct
position on the window portion due to the support frame
inclination resulting from the front-end drooping of the arm,
when the support frame is positioned simply with respect to
the window portion of the car body.
An object of this invention is to provide an
apparatus and a method which uses a robot having a swingable
arm and which correctly mounts the window glass by adjusting
the inclination of the support frame.
According to a first aspect of the invention there
is provided an apparatus for mounting window glasses on an
automobile in which a jig for holding the window glass is
supported on a support frame in such a manner that the jig
can be advanced and retracted as desired, said support frame
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being mounted on a robot and the robot is operated to
position the support frame at a location facing a window
portion of a car body on a conveyor line and, in this
condition, to move the jig forward to the window portion for
mounting the window glass therein, the robot comprising:
a robot arm swingable from a position outside the
car body conveyor line to said line and movable in the
directions of the length, width and height of the car body
with the car-width direction being taken as an X-axis
direction, the direction in which the upper and the lower
frames of the window portion face each other being taken as a
Y-axis direction and the direction perpendicular to both the
X-axis and Y-axis directions being taken as a Z-axis
direction;
the robot arm including a tilting shaft extending
in the Z-axis direction with the robot arm turned toward the
conveyor line, the support frame being tiltably mounted on
the tilting shaft;
a first detector provided on the support frame for
detecting any deviation in the X-axis direction of the jig
with respect to the window portion; and
a pair of second detectors provided on the support
frame for detecting deviations in the Y-axis direction of the
jig with respect to the window portion, the detection being
carried out at two locations which are symmetrical with
respect to the X-axis direction center line of the jig.
According to a second aspect of the invention there
is provided a method of mounting window glass to a window
portion of a car body on a car body conveying line using a
jig for holding the window glass and movably mounted to a
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support frame mounted to a robot arm swingable from a
position outside the car body conveying line to move the
support frame to a position facing a window portion of a car
body on the car body conveying line; said jig being movable
to advance and mount the window glass on the window portion
of the car body, said robot arm being movable in the
directions of the length, width and height of the car body
with the car-width direction being taken as an X-axis
direction, the direction in which the upper and the lower
frames of the window portion face each other being taken as a
Y-axis direction and the direction perpendicular to both the
X-axis and Y-axis directions being taken as a Z-axis
direction; the robot arm including a tilting shaft having an
axis extending in the Z-axis direction when the robot arm is
turned toward the conveying line, the support frame being
tiltably mounted on the tilting shaft; a first detector on
the support frame for detecting a deviation in the X-axis
direction of the jig with respect to the window portion; and
a pair of second detectors on the support frame for detecting
deviations in the Y-axis direction of the jig with respect to
the window portion, the second detectors being located at two
locations which are symmetrical with respect to the X-axis
direction center line of the jig; comprising the steps of:
turnin~ the robot arm toward the car body conveying
line;
positioning the jig at a predetermined position
facing the window portion; and
advancing the jig in the Z-axis direction to mount
the window glass on the window portion of the car body;
wherein the jig positioning step consists of:
(a) first, detecting a deviation of the jig with
respect to the window portion in the X-axis direction by the
first detector and moving, according to the deviation
detected, the jig in the X-axis direction so that the axis of
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the tilting shaft crosses the X-axis direction center line of
the window portion;
(b) second, detecting deviations of the jig with
respect to the window portion in the Y-axis direction by the
pair of second detectors positioned at locations which are
symmetrical with respect to the X-axis direction center line
of the jig and correcting the inclination of the jig with
respect to the window portion by tilting the support frame by
the tilting shaft in such a manner that the difference
between the deviations of the jig at these two locations
relative to the window portion in the Y-axis direction
becomes zero, and
(c) third, moving the jig in the Y-axis direction
by a distance equal to Y-axis directing deviation of the jig
detected when the difference between the deviations in the Y-
axis direction at the two positions was zero, in order to
correct the jig position in the Y-axis direction with respect
to the window portion.
According to a third aspect of the invention there
is provided a method of mounting window glasses on an
automobile including a car body haviny a window portion,
comprising the s~eps or:
holding a window glass in a jig mounted to the
working end of a robot arm;
positioning the jig in a position facing the window
portion of the car body, the jig being movable in three
directions which include an X-axis direction representing the
car-width direction, a Y-axis direction representing the
direction in which the upper and lower frames of the window
portion face each other, and a Z-axis direction representing
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the direction perpendicular to both the X-axis and the Y-axis
directions, and the jig being tiltable about a tilting shaft
which extends in the Z-axis direction and is located at the
center of the jig with respect to the X-axis direction; and
automatically mounting the window glass in the window
portion; said step of positioning of the jig being including:
(a) first, detecting a deviation of the jig with
respect to the portion in the X-axis direction ad moving,
according to the deviation detected, the jig in the X-axis
direction so that the tilting shaft is on the X-axis
direction center line of the window portion;
(b) second, detecting the jig deviations with
respect to the window portion in the Y-axis direction at
positions which are symmetrical with respect to the X-axis
direction center line of the jig and tilting, according to
the deviations detected, the jig by the tilting shaft to
correct the inclination about the Z-axis of the jig relative
to the window portion; and
(c) third, detecting the jig deviation relative to
the window portion ln the Y-axis direction and moving,
according to the deviation detected, the jig in the Y-axis
direction to correct the positional deviation of the jig in
the Y-axis direction.
The preferred embodiment of this invention provides
an apparatus for mounting window glasses on an automobile in
which a jig for holding the window glass is supported on a
support frame in such a manner that the jig can be advanced
and retracted as desired with the support frame mounted on a
robot. The robot is operated to position the support frame
at a location facing a window portion of a car body on a car
body conveyor line, and in this condition,
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move the jig forward to the window portion for mounting the
window glass therein. The robot is equipped with a robot arm
which can be swung from outside the car body conveyor line to
the line and is movable in the directions of the length,
width and height of the car body. When the car-width
direction is taken as an X-axis direction, the direction in
which the upper and the lower frames of the window portion
face each other taken as a Y-axis direction, and the
direction perpendicular to both the X-axis and Y-axis
directions taken as a Z-axis direction, the support frame is
mounted on the robot arm so as to be tiltable about a tiltin~
shaft extending in the forward-backward moving direction of
the jig so that the tilting shaft faces in the Z-axis
direction with the robot arm turned toward the conveyor line.
A first detector is provided on the support frame for
detecting a deviation in the X-axis direction of the jig with
respect to the window portion. A pair of second detectors
are further provided on the support frame for detecting
deviations in the Y-axis direction of the jig with respect to
the window portion, the detection being carried out at two
locations which are symmetrical with respect to the X-axis
direction center line of the jig.
After the window glass is set in the jig with the
robot arm turned away from the car body conveyor line, the
robot arm is swung toward the conveyor line and the jig is
moved in the Z- axis direction to the initial home position
facing the window portion of the car body. Then, the
deviation of the jig with respect to the window portion in
the X-axis direction is detected by the first detector.
According to the deviation thtls detected, the jig is moved in
the X-axis direction so that the axis of the tilting shaft
crosses the X-axis direction center line of the window
portion. Next, the deviations of the jig with respect to the
window portion in the Y-axis direction are detected by the
pair of second detectors located at the positions which are
symmetrical with respect to the X-axis direction center line
of the jig. Since the jig is already adjusted in its
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position in the X-axis direction as mentioned above, the
difference between the two Y-axis direction deviation of the
jig at the two symmetrical locations represents a parameter
signifying the inclination of the jig about the Z-axis
relative to the window portion. In order to correct the
inclination of the jig about the Z-axis, the support frame is
inclined by the tilting shaft so that the difference between
the two deviations at the symmetrical locations becomes zero,
with the result that the window portion center line in the X-
axis direction now coincides with the center line of the jigin the X-axis direction. Finally, the jig is moved in the Y-
axis direction to correct the Y axis direction position of
the jig. Now the jig is correctly positioned with respect to
the window portion of the car body. The jig is advanced
toward the window portion to mount the window glass on the
window portion correctly.
The invention will now be described in more detail,
by way of example only, with reference to the accompanying
drawings, in which:-
Figure 1 is a perspective view of one example of
the apparatus according to this invention;
Figure 2 and 3 are a side view and a plan view,
respectively, of the apparatus;
Figure 4 is a front view of the robot as-seen from
the line IV-IV of Figure 3;
Figure 5 is a plan view of the robot;
Figure 6 is a front view of the robot when the
window glass is set in the robot;
Figure 7 is a side view of the robot when the
window glass is mounted on the car body;
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Figure 8 is an enlarged cross-sectional plan view
showing a major part of the first detector;
Figure 9 is a cross-section view taken along the
line IX-IX of Figure 8;
Figure 10 is an enlarged cross-sectional side view
showing a major part of the second detector;
Figures 11 and 12 are cross-sectional views taken
along the lines XI-XI and XII-XII, respectively, of E'igure
10;
Figure 13 is an enlarged cross-sectional view of
major portion of the jig taken along the line XIII-XIII of
Figure 4;
Figure 14 is a flowchart showing the sequence of
steps carried out in positioning the jig; and
Figures 15a, 15b, 15c and d are diagrams showing
the positional relationships between the window portion and
the window glass during the process of positioning the window
glass.
Referring the Figures 1 through 3, a window glass
supply line 2 is installed alongside of and in parallel with
a car body conveyor line 1. The car body a is conveyed by a
hanger conveyor 3 along the conveyor line 1. Alongside of a
predetermined location on the conveyor line 1 where the car
body is to be stopped are installed two longitudinally
arranged robots 41~ 42 and two longitudinally arranged
transfer devices 51~ 52. The two transfer devices 51' 52
transfer a windshield glass bl and a rear window glass bz to
the robots 41 and 42, respectively. The front robot 41
mounts the windshield glass bl on a window portion W at the
front of the car body a and the rear robot 42 mounts the rear
window glass b2 on a window portion W at the rear of the car
body a.
The two robots ~1~ 42 have practically the same
cons~ruction a~d thus the robot 41 on the front slde will be
explained in detail in the following.
As shown in Figure 4 through 7, the robot 41
comprises a first slide table 6 moved by a cylinder 6a in the
car-length direction. A second table 7 is mounted on the
first slide table 6 and moved by a cylinder 7a in the car-
width direction. A rotary table 8 is mounted on the secondslide table 7 and rotated by a rotary actuator 8a about a
vertical shaft. An elevating table 9 is mounted on the
rotary table 8 and moved by a cylinder 9a in the car-height
direction alony a guide bar 9b. A robot arm 10 is pivotally
mounted on the elevating table 9 so as to be reversibly
rotatable about a horizontal shaft by a rotary actuator lOa.
The rotary table 8 gives the robot arm 10 a
swinging movement from a position outside the car body
conveyor line 1 to the line 1.
The first and the second slide tables 6 and 7 and
the elevating table 9 enable the robot arm 10 to move in the
car-length, car-width and car-height directions. The robot
arm 10 is provided at its front end with a support frame 12
on which a jig 11 for holding the windshield glass b1 is
supported in such a manner that the jig 11 can be moved back
and forth. As shown in Figure 6, the robot arm 10 is swung
away from the conveyor line 1 and is reversely rotated to
make the jig 11 face upward. In this condition, the
windshield glass bl is set on the jig 11 by the transfer
device 51. Then the robot arm 10 is, as shown in Figure 7,
swung toward the conveyor line 1 and at the same time is
reversely rotated through e predetermined angle so as to have
the windshield glass bl held in a predetermined downward
inclined position. Then the robot arm 10 is moved in the
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car-length, car-width and car-height directions according to
the teaching data to have the support frame 12 located at an
initial home position directly facing the window portion W
at the front of the car body a. The support frame 12 is
adjusted in position and the jig 11 is advanced toward the
window portion W to mount the windshield glass bl on the
window portion W.
The support frame 12 is mounted at the front end of
the robot arm 10 and can be tilted about a tilting shaft 13
extending in the direction in which the jig 11 is advanced
and retreated. This is described in detail in the following.
The car-width direction is taken as an X-axis direction, the
direction in which the upper frame and the lower frame of the
window portion W face each other is taken as a Y-axis
direction, and the direction perpendicular to both the X-axis
and Y-axis direction is taken as a Z-axis direction. The
support frame 12 is formed of a C type channel member
extending along the X-axis direction when the jig ll is
positioned at the initial home position. At the ends of the
support frame 12, a pair of cylinders 14, 14 are mounted in
such a manner that they cross both side walls of the channel
member so as to hold the jig 11 movable forwards and
backwards in the Z-axis direction. At the longitudinally
central part of the support frame ~2, the.tilting shaft 13
extending in the Z-axis direction is mounted such that it
also crosses the side walls of the channel material. The
robot arm 10 is then inserted into the support frame 12 and
the tilting shaft 13 is passed through the front end of the
robot arm 10 so that the tilting shaft 13 is supported on it.
The robot arm 10 also has a drive unit 15 located near the
arm-side end of the support frame 12, i.e., near the left end
of the support frame 12 in Figure 4. The drive unit 15
consists of an engagement pin 15a which engages with a
recessed groove formed at said end of the support frame 12
and a cylinder 15c which is connected to the pin 15a through
a connecting bar 15b. The drive unit 15 is actuated to tilt
the support frame 12 about the tilting shaft 13.
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The support frame 12 is also provided with a first
detector 16 and pair of second detectors 17. The first
detector 16 detects the deviation of the jig 11 relative to
the window portion W in the X-axis direction and the second
detectors 17 detect the displacement of the jig 11 relative
to the window portion w in the Y-axis direction. In more
detail, the first detector 16 consists of a pair of detecting
units 16a, 16a mounted at each end of a mounting frame 18 on
the support frame 12. Each of the units 16a comprises, as
shown in Figure 8 and 9, a rod 16b mounted to be swingable on
a shaft in the X-axis direction and an encoder 16d that
detects the swing of the rod 16b through a gear train 16c.
The two detecting units 16a, 16a are supported respectively
on guide bars 16e, 16e so that they are slidable in the X-
axis direction relative to the mounting frame 18. Rack bars16f, 16f are secured to the guide bars 16e, 16e. The rack
bars 16f, 16f are commonly in mesh with a pinion 16h on the
output shaft of a motor 16g which is installed at the
intermediate portion of the mounting frame 18. As a result,
the forward or reverse rotation of the pinion 16h causes the
two detecting units 16a, 16a to move synchronously with each
other inwardly or outwardly in the X-axis direction.
Here, the rods 16b are urged by a spring (not
shown) to swing inwardly (towards each other) in the X-axis
direction. After the support frame 12 is positioned at the
initial home position, the two detecting units 16a, 16a are
moved towards each other in the X-axis direction so as to
make the rod 16b engage, from outside, with the side frames
on both sides of the window portion W and have the bars 16b,
16b swing outwardly in the X- axis direction against the
force of the spring. A difference between angles of the
swings made as above respectively by the rods 16b, 16b of the
two detecting units 16a, 16a is used to determine a deviation
in the X-axis direction of the jig 11 with respect to the
window portion W.
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More specifically, when the jig 11 is deviated in
one direction, for example, toward the right along the X axis
car- width direction, with respect to the car body A, the rod
16b of the detecting unit 16a on the left comes into contact
with the left-side frame of the window portion W before the
rod 16b of the detecting unit 16a on the right does so with
the right side frame of the window portion W. As a result,
the swing angle of the rod 16b on the left is larger than
that of the rod 16b on the right. From this difference
between the two swing angles, the deviation of the jig 11 in
the X-axis direction is detected.
A pair of second detectors 17 are disposed on each
side of the mounting frame 18 so as to be symmetrical with
respect to the center line in the X axis direction of the jig
11. The details thereof are shown in Figures 10 to 12. A
bracket 17d is mounted to a holder 17a secured to the
mounting frame 18 through guide bars 17b, 17b and adjustment
screws 17c so that the bracket 17d can be moved and adjusted
in the Z-axis direction. Mounted on the bracket 17d so as to
be movable in the Y-axis direction along guide bars 17g, 17g
secured to the bracket 17d is a measuring arm 17f which has
at the front end an engagement piece 17e that is moved in
the Y-axis direction to come into contact with an upper frame
Wa of the window portion W. Also mounted to the bracket 1.7d
is an encoder 17j which has a pinion 17i engaged with a rack
17h that extends longitudinally in the Y-axis direction and
is secured to the measuring arm 17f. The encoder 17j detects
the position in the Y-axis direction of the measuring arm
17f. The measuring arm 17f is urged by a spring 17k in one
Y-axis direction so that the engagement piece 17e is in
resilient contact with the upper frame Wa. The measuring arm
17f is also driven by a cylinder 17 in the other Y-axis
direction against the spring 17k. With the engagement piece
17e separated from the upper frame Wa in the Y-axis
direction, it is relieved of the drive force by the cylinder
17 so as to have the engagement piece 17e come into
resilient contact with the upper frame Wa. The position in
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the Y-axis direction for the measuring arm 17f in this
condition is detected by the encoder 17j to measure the Y-
axis deviation of the support frame 12 with respect to the
window portion W.
The engagement piece 17e is pivotally mounted, at
its rear end, on a pivotal shaft 17m which extends in the Y-
axis direction so that the engagement piece 17e can be
pivoted in the Z-axis direction at the front end of the
measuring arm 17f7f. The measuring arm 17f has a cylinder
17n that turns the pivotal shaft 17m. After the jig 11 has
been properly positioned, the engagement piece 17e is
pivotally turned upwardly in the Z-axis direction by the
cylinder 17n from the position shown in Figure 10 so as to
disengage the engagement piece 17e from the upper frame Wa.
Then the measuring arm 17f is moved upwardly in the Y- axis
direction to retract the engagement piece 17e to a location
where it does not interfere with placement of the windshield
glass bl. A pad 170 is mounted to the front end of the
measuring arm 17f facing the external surface of the upper
frame Wa so as to protect the upper frame Wa from being
scored.
In this embodiment, for the first and second
detectors 16, 17 not to interfere with the setting of the
windshield glass bl on the jig 11, the mounting Erame 18 is
pivoted downward in Figure 6 by cylinder 18b, 18b about a
shaft 18a extending longitudinally along the support frame 12
and thus retracted out of the way when not needed.
Figure 14 shows a flow chart showing the process of
positioning the jig 11. After the jig 11 is positioned and
stopped at the home position, the first detector 16 detects
an X- axis deviation X of the jig 11 with respect to the
window portion W. At step 1 a check is made to see if the
deviation X is 0 or not. When, as shown in Figure 15(a), the
jig 11 and therefore the windshield glass bl held by the jig
11 is deviated i the X-axis direction and X is not zero, the
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program is advanced to step 2 where the required amount of X-
axis correction is calculated according to the value of X.
Then, at step 3 the required amount of X-axis correction is
output to move the jig 11 in the X-axis direction so that, as
shown in Figure 15(b), the axial line of the tilting shaft 13
crosses the X-axis direction center line of the window
portion W.
Next, the pair of the left-side and right-side
second detectors 17, 17 check at the two left- and right-side
locations Y-axis deviations of the jig 11 with respect to the
window portion W. At step 4 it is determined if the Y-axis
deviation Y on the left and the Y-axis deviation Yr on the
right coincide with each other. If the jig 11 is tilted
about the Z-axis relative to the window portion W, as shown
in figure 15(b), then Y is not equal Yr. In this case, the
program proceeds to step 5 where the required tilt correction
is calculated according to a difference between the deviation
Y and Yr. At step 6, the required tilt correction is output
to tilt back the support frame 12 about the tilting shaft 13.
As a result, the inclination of the jig 11 relative to the
window portion W is adjusted about the Z-axis, so that the-
upper edge of the windshield glass b1 becomes parallel with
the upper frame Wa of the window portion W and the center
line of the windshield glass b1 with respect to the X-axis
direction coincides with the center line of the window
portion W with respect to the X-axis direction, as shown in
Figure 15~c).
Next, the Y-axis deviations of the jig 11 detected
by the secondary detectors 17, 17 are represented by a
deviation Y from Y-axis direction reference deviation. At
step 7 it is determined if Y is zero or not. If Y is not
zero, the program goes to step 8 where it calculates the
required Y-axis correction. Then at step 9, the required Y-
axis correction so calculated is output to move the jig 11 in
the Y-axis direction until it is correctly positioned as
shown in Figure 15(d).
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Held in this position, the jig 11 is now advanced
in the Z-axis direction and the windshield glass bl is
correctly secured to the window portion W with bonding agent
ba applied beforehand to the glass bl.
In the example shown in the drawings, the window
glasses bl, b2 which are held in pallets 19 each having
suction disks l9a are supplied to the respective transfer
devices 51, 52 through the window glass supply line 2. On
the supply line 2, the window glasses b1, b2 are applied with
primer and then bonding agent by robots 20, 21. Then the
window glasses bl, b2, together with the pallets 19, are
transferred onto and set in the jig 11 mounted on the robots
41, 42 through the transfer devices 51, 52.
Each of the transfer devices 51, 52 comprises an
elevating frame 5b which is located alongside of the supply
line 2 and raised and lowered by a chain lifter 5a, and a
slide frame 5c of double structure which can be moved on the
elevating frame 5b toward and away from where the robot is
disposed. With the pallet 19 put on the slide frame 5c, the
elevating frame 5b is lifted and theslide frame 5c is
advanced laterally to move the pallet 19 so as to have it
positioned immediately above the jig 11 positioned as shown
in Figure 6. Then, the pallet 19 is positioned and secured
on the jig 11. After this, the slide frame 5c is retracted
to complete the transfer of the pallet 19 onto the jig 11.
As shown in Figure 4 and 13, the jig 11 comprises:
a plurality of clamp members lla that removably hold the
pallet 19; a vacuum pad llb piped to the suction disk l9a on
the pallet 19 with its back-side vacuum connecting portion
l9b connected to the vacuum source on the robot side; and a
valve operation member llc used to operate an open air valve
l9c connected to the vacuum piping on the pallet 19 in order
to relieve the suction disk l9a of the vacuum action being
applied thereto. After the window glasses b1, b2 are mounted
on the window portions W as described above, the open air
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valve l9c is operated by the valve operation member llc to
release the window glasses b1, b2 from the vacuum grip by the
suction disks l9a. Then the robot arm 10 is swung toward
outside the conveyor line 1 and reversely rotated about the
horizontal shaft to the position shown in Figure 6 and at the
same time the slide frame 5c is advanced to receive thereon
the empty pallet 19 on the jig 11. Next, the slide frame 5c
is retracted and the elevating frame 5b is lowered to
discharge the empty pallet 19 onto the pallet return line 22
lo on the lower side of the window glass supply line 2.
A setting device 23 is provided at the front end of
the supply line 2 which sets the rear window glasses b2 and
the front windshield glasses bl successively onto the pallets
19 that were returned via the return line 22.
As described in the foregoing, according to this
invention, a window glass held through the jig on the support
frame mounted at the front end of the robot arm is brought
from outside the car body conveyor line to the line by
swinging the robot arm. Unlike a conventional one of the
kind in which the robot is suspended above the conveyor line,
the window glass mounting apparatus according to the
invention permits the use of a hanger conveyor for conveying
the car body through the conveying line. This permits a
greater degree of freedom in designing the automobile
assembly line. Furthermore, since the inclination of the
support frame with respect to the car body due to the front-
end drooping of the robot arm is corrected, the window glass
can be correctly mounted on the window portion of the car
body, thus improving the productivity in the assembly line.
It should be understood that the specific form of
the invention hereinabove described is intended to be
representative only, as certain modifications within the
scope of these teachings will be apparent to those skilled in
the art.
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