Note: Descriptions are shown in the official language in which they were submitted.
1 33~862
The present invention relates to a method for
transporting vehicle bodies in an automobile body welding line.
Vehicle body welding lines are known in which a vehicle
body is assembled by welding and attaching a floor, a roof and
side panels which form a vehicle body of an automobile at a
vehicle body assembly station (hereinafter referred to the
assembly station), the resulting vehicle body is transported from
the assembly station to the discharging station in front thereof
by transfer means moveable between the both stations, and the
vehicle body is then transported from the discharging station to
an additional welding line where additional welding for the
vehicle body is performed.
A large number of welding robots having welding guns
carried thereon are disposed in the additional welding line, and
line-stopping of the additional welding line for a short time may
often occur due to a small problem such as the escape of a
pressurized air in the welding gun.
When the line-stopping of the additional welding line
occurs the transportation of the vehicle body from the
discharging station to the additional welding line is also
stopped, making it impossible to transport the vehicle body from
the assembly station to the discharging station. Thus, the
assembled vehicle body cannot be discharged and remains in the
assembly station and hence, assembling of a next vehicle body
cannot be performed in the assembly station, causing the stopping
of the whole of a vehicle body welding line.
Japanese Unexamined Patent Application Publication No.
63576/88 discloses a vehicle body welding line in which a
shunting station for a replacing carriage for welding ~igs is
provided at the middle between the assembly station and the
discharging station, with a longer distance provided
therebetween, so that a replacement carriage may be introduced
s 1 337862
from the shunting station to the assembly station to replace
welding jigs of a welding machine disposed in the assembly
station, and a vehicle body receiver is provided in the shunting
station so that the vehicle ~odies may be sequentially
S transported from the assembly station to the discharging station
through the shunting station. Even with this welding line, when
the line-stopping of the additional welding line occurs, the
transporting of the vehicle body from each of the discharging
station and the shunting station is stopped and as a result,
eiection of the assembled vehicle body from the assembly station
cannot be perfonmed, causing the stoppi~g of the whole of a
vehicle body welding line.
The present invention provides a method for
transporting vehicle bodies, wherein even if the line-stopping of
the additional welding line for a short t~me occurs, any
influence cannot be exerted on the assembly station, thereby
increasing the operating efficiency and improving the
productivity.
According to the present invention, there is
provided a vehicle body welding line, which comprises an
assembly station in which a vehicle body for an automobile
may be assembled, a discharge station located further down
the line from the assembly station, a transfer bar
reciprocally movable between the assembly station and the
discharge station so as to be capable of moving a vehicle
body from the assembly station to the discharge station, the
transfer bar being mounted moveably on the movable frame by
means of at least one link mechanism comprising a first link
pi~otally connected to the movable frame and a second link
pivotally connected to the transfer bar so that the transfer
bar may be raised and lowered with respect to the movable
frame, and means for transporting a vehicle body from the
discharge station to a succeeding additional welding line,
wherein the assembly station and the discharge station are
.~ .
-
1 337~3~2
_ spaced from each other by a distance greater than thelength of the vehicle to be welded, and the transfer means
is also capable of transferring a vehicle body to an
intermediate position between the assembly station and the
discharge station.
With this, even if the line-stopping of the additional
welding line occurs to cause the stopping of the transportation
of a vehicle body from discharging station, the vehicle body
assembled in the assembly station is discharged from the assembly
station and transported to the intermediate position between the
assembly and discharging stations by the transfer means and can
be placed on standby, so that the assembling operation for a next
vehicle body can be performed in the assembly station.
When the line-stopping of the additional welding line
has been released and the vehicle body has been transported from
the discharging station, the vehicle body on the standby in the
intermediate position is transferred to the discharging station
and thereafter, the transporting of the vehicle body from the
assembly station to the discharging station is perfonmed
synchronously with the transporting of the vehicle body from the
discharging station.
The line-stopping of the additional welding line
occurring sometimes in the additional welding line is for a short
ti~e and in many cases, may be due to recoverable light troubles.
Up to the time when the assembling operation for the next vehicle
body on standby in the intermediate position is completed in the
assembly station, the line-stopping is released and thus, the
whole of a vehicle body welding line can be hardly stopped due to
the line-stopping of the additional welding line.
The present invention will be further illustrated by
way of the accompanying drawings in which:-
~ ig. 1 is a plan view of a section between an assemblystation and a discharging station in a welding line to which the
present invention is applied;
-- 3
~3
~ 337~2
Fig. 2 is a side view taken along line II-II in Fig. l;
Fig. 3 is a front view of the assembly station during
assembling of a vehicle body;
Fig. 4 is an enlarged longitudinal sectional view of an
essential portion of transfer means;
Fig. 5 is a laterally cross-sectional view taken along
a line V-V in Fig. 4;
Fig. 6 is a side view of the welding line, similar to
Fig. 2, during transporting of a replacing carriage; and
Fig. 7 is a front view of the assembly station during
replacing of ~igs.
Referring to Figs. 1 and 2 , the reference character A
designates an assembly station, and the character B denotes a
dlscharging station located in front of the assembly station. An
automatic welding machine 2 is disposed at each of opposite sides
of the assembly station A and includes a welding ~ig 1 having
various welding guns la carried thereon for welding and attaching
a floor, a roof and side panels which are components for a
vehicle body, as shown in Fig. 3, and a transfer bar 4 as
transfer means is mounted on a central track 3 extending
forwardly from the assembly station A. Thus, a vehicle body W
assembled by welding and attaching the floor, the roof and the
side panels in the assembly station A is transported to the
discharging station B by the transfer bar 4 and placed onto a
vehicle body receiver 5 disposed in the discharging station, and
the vehicle body W is then transported from the discharging
station to a succeeding additional welding line by transporting
means such as a hanger.
As shown in Figs. 4 and 5, the transfer bar 4 is
- 1 337862
liftably supported on a movable frame 6 through two sets of front
and rear link mechanism 7, 7 each of which comprises a lower link
7a pivotally connected to the moveable frame 6 and an upper link
7b pivotally connected to the transfer bar 4, so that it can be
raised and lowered in a horizontal attitude in such a manner to
synchronously operate the both link mechanisms 7, 7 by a cylinder
7c through a synchronous rod 7d. The movable frame 6 is moveably
supported on a pair of left and right guide rails 3a, 3a on the
central track 3 through a plurality of sets of rollers 6a, which
are disposed as to be longitudinally spaced one another. A
travelling motor 6c is carried on the movable frame 6 and has a
pinion 6b provided on an output shaft and meshing with a rack 3b
on the central track 3, so that the movable frame 6 and thus the
transfer bar 4 can be longitudinally moved by the motor 6c. When
the movable frame 6 has been moved to a retreated position in
which it is restrained by a stopper 3c mounted on a portion of
the central track 3 closer to the assembly station A, a rear end
of the transfer bar 4 projecting rearwardly from the movable
frame 6 is inserted into a lower side of the vehicle body W held
between the welding jigs 1, 1 in the assembly station A, and the
transfer bar 4 is raised to support the vehicle body W by a
support member 4a mounted on an upper surface of the rear end of
the transfer bar 4. Then, the movable frame 6 is advanced to an
advanced position in which it is restrained by a stopper 3d at a
front end of the central track 3, and the transfer bar 4 is then
lowered, thereby transporting and placing the vehicle body W onto
the vehicle body receiver 5 on the discharging station s.
It should be noted that when line-stopping of the
additional welding line occurs, the transporting of the vehicle
body from the discharging station to the additional welding line
is also stopped, so that the vehicle body W which has been
earlier transported to the discharging station B remains in the
discharging station B, and a next vehicle body cannot be
transported to the discharging station s.
" 1 337862
Thereupon, in the present embodiment, the discharging
station s is provided at a space larger than one vehicle body in
front of the assembly station A, so that when the vehicle body W
has been incapable of being discharged from the discharging
station s upon the line-stopping of the additional welding line,
the transfer bar 4 is stopped in the course of the advancing
movement to the discharging station s, and the vehicle body W
which has been assembled in the assembly station A is transported
to and placed on standby in an intermediate position between the
assembly station A and the discharging station B, as shown by a
phantom line in Fig. 2. ThiS enables the assembling operation
for the next vehicle body to be performed in the assembly station
A. When the line-stopping of the additional welding line has
been released to restart the transporting of the vehicle body
from the discharging station B, the vehicle body on standby in
the intermediate position is transported to the discharging
station B.
In Figures, the reference numeral 8 designates a
replacing carriage for the welding jigs 1. Supporting frames 8b
are carried on the replacing carriage 8 and have two sets of left
and right grasping members 8a mounted thereon in correspondence
to the welding machines 2, 2 at the opposite sides of the
assembly station A for grasping the welding jig 1 in docking
members lb mounted in a projecting manner on the welding jig as
shown in Figs. 6 and 7. Therefore the welding jigs 1, 1 may be
replaced between the welding machines 2, 2 at the opposite sides
when the replacing carriage 8 is transferred into the assembly
station A.
The replacing carriage 8 is transported from a shunting
station C provided between the assembly and discharging stations
A and B to the assembly station A. More specifically disposed on
each of opposite sides of the central track 3 are travelling
rails 9, 9 for replacing carriage 8, which extend from the
shunting station C to the assembly station A, and a pair of
-- 6
1 337862
replacing rails 10, lO extending laterally at each of opposite
sides of the shunting station C. Shunting rails 11 are provided
at intersection portions between each of the travelling rails 9
and each of the replacing rails 10 which are located at four
corners of the shunting station C and is turnable by a cylinder
lla between a longitudinally directed position in which it is
aligned with the travelling rail g and a laterally directed
position in which it is aligned with the replacing rail 10. with
the shunting rails 11 in their laterally directed positions, the
replacing carriage 8 can be moved through the replacing rail 10
into and out of the shunting station C, and with the shunting
rails 11 in their longitudinally directed positions, the
replacing carriage 8 can be moved reciprocally between the
shunting station C, and the assembly station A.
The replacing carriage 8 is provided, at four corners
on its lower surface, with casters 8c each of which is turnable
about a vertical axis to follow turning of the corresponding
shunting rail 11. Further, an engage portion 4b is mounted to
the rear end of the transfer bar 4 and can be brought sideways
into and out of engagement with the front end of the replacing
carriage 8. With the transfer bar 4 moved to the front of the
shunting station C, the front end of the replacing carriage 8 is
brought into engagement with the engage portion 4b by introducing
the replacing carriage 8 through the replacing rail 10 into the
shunting station C, so that the replacing carriage 8 may be
reciprocally moved between the shunting station C and the
assembly station A by the transfer bar 4.
In replacing the jigs, the empty replacing carriage 8
is first introduced through the replacing rails 10 at one side
into the shunting station C and transported to the assembly
station A where the used welding jigs 1, 1 are shifted onto the
replacing carriage 8, following which such replacing carriage is
moved back to the shunting station C and taken out to the
replacing rail 10 at the one side. Then, the replacing carriage
1 337862
8 carried the welding jigs 1, 1 to be subsequently used thereon
is introduced through the replacing rails 10 at the other side
and transported to the assembly station A where such welding jigs
1,1 are shifted onto the welding machines 2, 2 following which
the replacing carriage 8 is moved back to the shunting station C
and taken out to the replacing rails at the other side, thus
completing the replacing operation.
As discussed above, according to the present invention,
even if the transporting of the vehicle body from the discharging
station is stopped due to the line-stopping of the additional
welding line, the assembling operation for a next vehicle body
can be performed in the assembly station by transporting the
vehicle body assembled in the assembly station to the
intermediate position between the assembly and discharging
stations and placing it on standby and thus, an influence due to
the line stopping occurring sometimes for a short time in the
additional welding line cannot be exerted on the assembly
station. This leads to effects of an increase in operating
efficiency of the entire line and an improvement in productivity.
