Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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FIELD OF THE INVENTION
The invention relates to a mastic applicator tool that i8
attached to a robot, such as a riveting robot, whereby the mastic
material may be a sealant, an adhesive or the like that is
applied around the edges of a rivet hole prior to the riveting
operation.
BACKGROUND INFORMATION
German Patent Publication (DE-PS) 3,232,093, corresponding to
U. S. Patent 4,548,345 (Puritz et al.~, issued on November 22,
1985, discloses an automatic riveting robot including the
following components: a drilling feed advance unit, a rivet
supply unit, and a riveting unit. Each of these units is mounted
in a controllable manner to a support console and extends in a
radial direction relative to a riveting position, or rather
radially relative to an axis extending centrally through a
riveting hole. Each of these units is movable in the required
directions by respective controllable drives. Pneumatic
couplings, electrical connectors, as well as clamping mechanisms
for securing the riveting machine to a manufacturing robot are
mounted on the support console. Such a conventional machine is
capable of producing rivet connections, for example, on an
aircraft structural component in accordance with a respective
riveting program, whereby the drilling of the riveting holes, the
insertion of the rivets into the holes, and the setting of the
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ivets takes place in an automatic manufacturing sequence in
accordance with the riveting program stored in a memory of the
robot control unit.
In order to improve the corrosion protection of rivet connections
produced in an automatic sequence, it is necessary that the gap
between a rivet head and the structural component surface i8
automatically sealed during the riveting operation by means of
a mastic sealant. However, the just described robot operated
riveter is not capable of providing such seals.
OBJECTS OF THE INVENTION
In view of the foregoing it is the aim of the invention to
achieve the following objects singly or in combination:
to provide a mastic material applicator tool that can
be attached to a manufacturing robot and thus become part of an
automatic riveter of the type described above;
to construct the applicator tool in such a way that it
can be secured to the support console of the automatic riveter,
whereb~ the support console carries the clamping elements as well
as connector couplings for the supply of energy as well as the
transmittal of electrical control signals; -
to construct such an applicator tool in such a manner
that the mastic sealant can be applied as one step within the
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Oequence of an automatic riveting operation, whereby the sealant
must be applied on the surface of a rim surrounding a rivet bore
hole; and
to construct the applicator tool in such a way that it ;-~
can receive and dispense the mastic material from a cartridge. ~ -
SUMMARY OF THE INVENTION
The above objects have been achieved according to the invention
by the combination of the following features. An applicator head
is mounted on a robot support console for movement at least in
two directions, whereby the X-direction extends radially relative
to a central axis of the applicator head that coincides with the
central axis of a rivet hole or bore when the applicator head is
in a mastic applicating position, and wherein the Y-direction
extends in parallel to the central longitudinal axis of the
applicator head. The movement in the X-direction is accomplished
by a slide movably supported on a radially extending guide. The
movement in the Y-direction is accomplished by a Y-direction
guide mounted on the slide and having in turn mounted thereto the
applicator head through a support or mounting arm. Separate
drives are provided for moving the slide radially or horizontally
and for moving the support or mounting arm relative to the Y-
guide in a direction parallel to the central axis of the
applicator head. These drives are power drives and may comprise
piston cylinder devices or other suitable drives, for example
rack and pinion drives, electric motor drives, hydraulic drives
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dnd the like. The applicator head comprises a supply volume that
preferably receives the mastic material inside a cartridge.
However, filling the mastic material directly into the supply
volume may also be feasible. The applicator head further
includes pressure supply couplings for the pressurized dispensing
of dosed quantities of mastic material through a discharge nozzle
also forming part of the applicator head.
Preferably, the discharge nozzle of the applicator head is
provided with a dosing volume that can be filled prior to any
discharge of mastic material through one or more nozzles. This
feature of the invention has the important advantage that mastic
material will be dispensed in exact quantities so that waste and
soiling the surface to be riveted is minimized.
BRIEF DESCRIPTION OF THE DRAWINGS
In order that the invention may be clearly understood, it will
now be described, by way of example, with reference to the
accompanying drawings, wherein: -
. ~ ,
Fig. 1 is a side view, partially in section, of the
applicator tool according to the invention,
whereby the coordinate directions X and Y are
also illustrated;
Fig. 2 is a view in the direction II in Fig. 1;
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~ig. 3 is a view in the direction III in Fig. 1;
Fig. 4 is a view similar to that of Fig. 1 on a somewhat
enlarged scale to provide more space for refer-
ence numbers;
Fig. 5 is a view in the direction of the arrow V in
Fig. 4; and
Fig. 6 is an axial sectional view through the applicator
head showing further details of its construction.
DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT AND OF THE
BEST MODE OF THE INVENTION
.
Referring to Figs. 1, 2, 3, and 4 in conjunction, the applicator
tool 1 will first be described. The details of the applicator
head 6 will be described below with reference to Fig. 6. The
applicator tool 1 is mounted for movement in two directions X
and Y on a console support 2 of a riveting robot. Further
details of the riveting robot are described in the above
mentioned U. S. Patent 4,548,345. As shown in Fig. 2, the
console 2 itself is movable in the three directions of space X',
Y' and Z'. The drive mechanisms for performing the motions in
the X~, Y' and Z~ directions are part of the riveting robot.
Figs. 1 to 4 show the tool 1 in its rest position, namely with
the applicator head 6 in its uppermost position in the Y-
direction and in the po~ition all the way to the right in the X-
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~irection. The applicator head is mounted by two distinct
guides 3 and 7. The guide 7 is referred to as a first guide for
controlling the movement in the Y-direc~ion which extends in
parallel to a central longitudinal axis A of the applicator
head 6. The guide 3 is a second guide and controls the movement
in the X-direction, which is the radial direction. A first drive
mechanism 11 drives the applicator head 6 in the Y-direction
parallel to the central axis A of the head 6. A second drive 3A
drives the head, including its first drive 11 in the X or radial
direction. ~or this purpose, the first guide 7 i8 mounted to a
slide 4 which in turn is secured to a saddle 3D that forms part
of the second drive 3A as will be described below. The head 6
is mounted by screws 22 to a mounting or support arm 5 which in
turn is secured to an upright guide profile 13 best seen in
Fig. 5. The profile 13 forms part of the cross guide or vertical
guide 7. More specifically, the vertical guide profile 13 has
an inverted U-profile with a left-hand leg 13A welded at W to the
arm 5 and a right-hand arm 13B rigidly secured to or forming an
integral part with a cantilever 16 connected to the first
drive 11. The vertical movement of the upright guide profile 13,
and thus of the arm 5 with the applicator head 6, is guided by
an upright guide post 14 rigidly secured to an elbow 4A of the
slide 4 as best seen in Figs. 4 and 5. More specifically, a
guide prism 15 rigidly secured to the guide profile 13 slidçs in
a groove 14A of the upright guide post 14. The first drive
mechanism 11 comprises a piston cylinder device with a
cylinder llC rigidly secured to the slide 4 and a piston P
axially movable up and down in the cylinder llC. The piston P
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is connected to a piston rod 12, the upper free end of which is
connected to the cantilever 16 by two adjustable nuts 16A
and 16B. Air pressure hoses 17 and 18 are connected to the
cylinder llC by coupling devices llA and llB, for example, of the
quick coupling type. Pressure application through the pressure
hose 17 lowers the tool head 6. Pressure application through
pres6ure hose 18 lifts the pressure head which is shown in
Fig6. 1 and 4 in its uppermost rest position as mentioned.
Two contactless position sensors 37 shown in Fig. 1, but not
shown in Fig. 4, sense the uppermost and the lowermost position
of the cantilever 16 to provide a respective control signal. The
sensors 37 may be of any suitable conven~ional type, such as
magnetic sensors, light sensors, or the like.
The second guide 3 comprises a so-called pneumatic cylinder
without a piston rod that performs a driving function as well as
a guiding function. Such piston cylinder devices are manufac-
tured by Martonair Lintra. Such devices do not have a piston
rod. The saddle 3D on which the slide 4 is mounted is connected
through a longitudinal slot in the wall of the cylinder 3A to the
piston. The longitudinal slot is sealed by a flexible seal that
permits the axial back and forth movement of the connection
between the saddle 3D and the piston inside the cylinder 3A. The
ends of the cylinder 3A are closed by covers 3E that are provided
with coupling inlets 3B and 3C. These coupling inlets are
;;~ 25 connected to air pressure ho~es 19 and 20 respectively.
lncidentally, all pressure hoses used2~e~e2in are sufficiently
flexible to permit the described movements of the components.
The end covers 3E of the cylinder 3A are mounted to the support
console 2 of the riveting robot by mounting blocks 2A secured to
the console 2 by screws or the like. An air pressure hose 19 is
coupled to the left-hand end of the cylinder 3A by a coupler 3B.
An air pressure hose 20 iS coupled to the right-hand end of the
cylinder 3A by a coupler 3C. Four rods 3F are holding the
cylinder 3A in place and reach from the left-hand end cover 3E
to the right-3E. A further mounting block 2B also supports the
cylinder 3A on the console 2. The longitudinal central axis E
of the cylinder 3A extends radially through the vertical axis A
of the applicator head 6 and at right angles thereto. Application
of pressure through the hose 19 and the coupler 3B to the left-
hand end of the cylinder 3A moves its piston and thus the saddle
3D and the slide 4 with all the components mounted to the slider
4, into the right-hand position shown in Figs. 1 and 4.
Pressure application through the hose 20 and the coupler 3C to
~ the right-hand end of the cylinder 3A moves the saddles 3D to the
: 20 left in Figs. 1 and 4. The movements of the saddles 3D are
guided by the upper rod 3F shown in Figs. 1 and 2. Four such
rods 3F ar~ provided, but only the upper tool rods participate
in guiding the saddle 3D horizontally back and forth.
Referring again to Figs. 1 and 4, a flexible air pressure
hose 34 i6 coupled through a coupler 34A to the upper end of the
applicator head 6. A venting valve 28 is connected to the
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,lexible air pressure hose 34 for venting the applicator head 6
for avoiding discharging too much of mastic material. The
venting valve 28 in turn is connected to an air pressure hose 9
which leads to a source of compressed air not shown, but forming
part of the riveting robot.
When the saddle 3D is moved to the left, the slide 4 and all
components mounted thereon also moves to the left to bring the
longitudinal axis A of the head 6 into vertical alignment with
rivet hole R~ in the work piece WP shown in dashed lines in
Fig. 1.
Instead of using piston cylinder drives llA for the first drive
and 3A for the second drive, it is possible to replace these
drives by spindle drives, rack and pinion drives, hydraulic motor
drives, and similar drives including controllable electric motor ~-
drives.
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Referring to Fig. 6, the applicator head 6 comprises a housing,
pre~erably a tubular housing 21 which is connected to a mounting
plate 2lA welded to the housing 21 by welding seams W. The
plate 21A is secured to the mounting or carrier arm 5 by screws
22. This feature permits a rapid exchange of the applicator
head 6. The housing 21 has a lower larger inner diameter and an
upper smaller inner diameter to form a shoulder 21B facing
downwardly. The applicator head 6 further comprises an inner
tubular member 23 slidingly received in the two bores. For this
purpose, the tubular member 23 has a larger diameter lower end
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~nd a smaller diameter upper end to form an upwardly facing
shoulder 23A. A ring chamber is formed between the two
shoulders 21B and 23A. A compression spring 24 is received in
the ring chamber. The spring 24 biases the inner tubular
member 23 into its lowermost position as shown in Fig. 6. In
this position a nut 25, preferably a knurled nut as shown in
Fig. 3 rests against the upwardly facing end face of the
housing 21. The nut 25 i8 threaded onto a threaded upper end
23B of the inner tubular member 23. When the housing 21 and the
tubular member 23 are positioned relative to each other as shown
in Fig. 6, upward movement of the tubular member 23 relative
to the housing 21 is possible against the bias of the compression
spring 24. A tubular bushing 27 for holding mastic material in
a volume 8 is held inside the tubular member 23 by cooperating
threadings 26. The tubular bushing 27 may, for example, hold a
mastic containing cartridge C in the space 8. The cartridge C
has flanges 28 that are clamped in place between a downwardly
facing shoulder 23C of the tubular member 23 and the upwardly
facing end face of the bushing 27. The cartridge C has a
cartridge tip CT that is held in place by a nipple 32A of the
discharge nozzle 10. The nipple 32A surrounds a bore 32 in the
discharge nozzle 10 and the cartridge tip CT is held in the
bore 32, preferably in a threaded manner. The discharge
nozzle 10 is provided with 1, preferably a plurality of nozzle
openings 33 that communicate the bore 32 with the outside.
Preferably, the nozzle openings 33 open into a shoulder 31 of the
nozzle 10. The shoulder 31 surrounds a guide pin 30 for guiding
the nozzle into a rivet hole RH when the central longitudinal
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f~
~xis A of the applicator head 6 is vertically aligned with the
central axis of a rivet hole RH. Preferably, the nozzle
openings 33 are distributed at equal angular spacings around the
axis A in the shoulder 31. The nozzle 10 itself is held in place
by a retaining nut 29 that is screwed to a threaded lower end of
the tubular bushing 27 by threadings 29A.
The tubular member 23A is provided with a central longitudinal
throughbore 23D that communicates the space 8 and thus the
interior of the cartridge C with the air pressure hose 34 through
the coupling 34A for discharging mastic material through the
nozzle openings 33.
The upper end of the tubular member 23 below the threaded
end 23~ is provided with an axially extending radially outwardly
facing groove 35A in which a set screw 35 is received with its
radially inner end to prevent a rotation of the tubular
member 23 around the longitudinal axis A of the applicator
head 6. Once the set screw 35 is properly adjusted to the
~; correct depth in the groove 35A, a nut is tightened to bear
against the housing 21 for holding the set screw 35 in place.
:20 :The set screw 35 permits an axial movement of the tubular member
23 relative to the housing 21, but, as mentioned, rotational
movement between the housing 21 and the tubular member 23 is
: prevented.
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~he present mastic applicator tool operates in combination with
a riveting robot as follows. First, the robot moves the support
console 2 along a precisely determined distance to a position
next to the rivet hole RH. Next, the operational units of the
riveting robot are activated in sequence, starting vith the
drilling unit. When the rivet hole RH has been drilled, the
applicator head 6 is brought into alignment with the drilled
hole, whereby the guide pin 30 enters partly into the drilled
hole to avoid contact between the shoulder 31 and the surface
edge around the drilled hole. The tool 1 is brought into the
just mentioned position by the proper activation of the drives
3A and 11. The lowering of the applicator head 6 is precisely
controlled 60 as to maintain a defined air gap between the
downwardly facing surface of the shoulder 31 and the upwardly
facing surface of the work piece WP. While the applicator head
6 is on its way downward, air pressure is applied through the
hose 34 and coupling 34A to prefill the space 32 which thus
functions a~ a dosing volume. Further air pressure is applied
once the applicator head 1 has reached its position with the
required air gap between the shoulder 31 and the surface of the
work piece, whereby the precise quantity of mastic material, such
a6 an adhesive or a sealing material is squirted out through the
nozzle openings 33. As a result, and assuming that there are six
outlet openings 33, six little balls of mastic materials are
positioned on the edge around the rivet hole. The precise
discharge quantity including the size of the individual mastic
material balls can be adjusted by the size of the air pressure
and by the duration of the pressure application. An unintended
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~. .
further flow of mastic material is prevented by the above ment-
ioned venting valve 28 which vents the air pressure in the bore
23D and in the hose section 34 to a void. The valve 28 may be
a separately controlled valve or a magnetic valve that controls
the supply of air pressure to the hose 34 to provide a venting
as the valve shuts off the pressure supply.
Under normal operating conditions the centering pin 30 of the
applicator nozzle 10 properly guides and centers the head 6
relative to a rivet hole while assuring the above mentioned air
gap between the shoulders 31 and the surface of the edge around
the rivet hole. Further, upon application or discharge of the
mastic material the head 6 returns immediately into its upper
position substantially without dwelling in the discharge
position.
In case there i6 a defect in the system, whereby the centering
pin 30 should contact the edge around a rivet hole, the
spring 24 makes sure that the centering pin 30 can yield against
the bias of the spring 24. Thus, damage to the work piece is
~ positively avoided.
:
Incidentally, the air gap between the surface of the work piece
and the shoulder 31 is so selected that the discharged mastic iB
evenly distributed by the shoulder 31. The gap properly
dimensioned also makes sure that the discharged material is not
squeezed radially away from the edge around the rivet hole. The
proper prefilling of the space 32 is important because it takes
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a certain amount of time to fill the space 32. Thus, it must be
made sure that the space 32 is filled prior to the point where
the applicator head 6 has reached its discharge position with the
proper air gap between the shoulder 31 and the surface of the
work piece. In this way it iB possible to start the filling of
the space 32 at a time when the rivet hole itself is still being
drilled. The control parameters for this purpose are determined
by experiment and the respective timings and distance displace
ments are then entered into the central processing unit of the
rivet robot.
Once the mastic has been applied and the head 6 removed, the
rivet can be inserted into the hole and set. As mentioned, the
applicator head may dispense different types of mastic materials
including adhesive6, sealants, and the like and it i6 not
absolutely necessary to use a cartridge C in the space 8. The
mastic material could be filled into the space without a
cartridge.
Although the invention has been described with reference to
specific example embodiments, it will be appreciated that it is
intended to cover all modifications within the scope of the
appended claims.
