CA2112428A1 - Mastic material applicator tool for a robot - Google Patents

Abstract

TITLE OF THE INVENTION

MASTIC MATERIAL APPLICATOR TOOL FOR A ROBOT

ABSTRACT OF THE DISCLOSURE

A mastic material applicator tool is constructed for use in an automatic riveting robot. The tool is secured to a support console of the robot and all power and electrical connectors between the tool and the robot are provided at an interface between the tool and the robot. Two guides and two drive mechanisms are so arranged that an applicator head is movable in the X-direction or radially to a central axis through a rivet hole and in the Y-direction which coincides with or parallels the central axis through a rivet hole. Both drives are power operated and controlled by the central processing unit of the riveting robot for precisely positioning a discharge nozzle of the applicator head so that a gap is formed between the nozzle discharge openings and the rim surface of the work piece surrounding a rivet hole. A discharge nozzle is provided with a precisely dimensioned volume to receive a dosed volume of mastic material prior to discharging such dosed vo4lume.

Description

` 21~2~

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 2 ;

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 ~ 2112~28 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 ~ . . .: .

` ~ 2112~28 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;

112~28 ~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-~,.. ~. . . . .

- 2112~28 ~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

~` 2112~28 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 2 1 12 Li28 ,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.
, ' .. ~ -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 ~' -- 2112~28 ~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 11 ':

2~12~28 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.

~ ' '' ~ ' 2112~2~
~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 2112~2~
~. .
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 '~

21~2~2'~
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.

Claims (13)

1. A mastic material applicator tool for a robot comprising an applicator head for holding mastic material, said applicator head having a longitudinal axis extending in a Y-direction, a mounting arm holding said applicator head, said mounting arm extending radially relative to said longitudinal axis, an axial first guide holding said mounting arm for a guided axial movement parallel to said longitudinal axis, an axial first drive for axially moving said applicator head in said Y-direction of said longitudinal axis, a radial second guide including a slide carrying said axial first guide and extending radially relative to said longitudinal axis in an X-direction, a radial second drive for moving said slide radially in said X-direction relative to said longitudinal axis, said applicator head comprising a volume for holding mastic material, a discharge nozzle having at least one nozzle opening for discharging mastic material, and a pressure application device for driving mastic material out of said at least one nozzle opening onto a rim around a previously drilled hole.

2. The applicator tool of claim 1, wherein said first axial drive and said second radial drive comprise piston cylinder drives.

3. The applicator tool of claim 1, wherein said first axial drive and said second radial drive comprise electric motors and respective power trains for axially moving said mounting arm and for radially moving said slide.

4. The applicator tool of claim 1, wherein said first axial drive and said second radial drive comprise hydraulic motors and respective power trains for axially moving said mounting arm and for radially moving said slide.

5. The applicator tool of claim 1, wherein said applicator head comprises a tubular sleeve for tightly holding a cartridge containing mastic material.

6. The applicator tool of claim 1, wherein said applicator head comprises a housing and screw connections securing said housing to said radially extending mounting arm.

7. The applicator tool of claim 1, wherein said discharge nozzle comprises a centering pin or guiding an insertion into a drilled hole.

8. The applicator tool of claim 7, wherein said centering pin of said discharge nozzle comprises a shoulder and said nozzle comprises a plurality of nozzle bores for discharging mastic material, said nozzle bores opening in said shoulder.

9. The applicator tool of claim 8, wherein said nozzle bores are angularly spaced from each other around said longitudinal axis at equal angular spacings between neighboring nozzle bores.

10. The applicator tool of claim 9, wherein said discharge nozzle comprises a central sleeve surrounding a central dosing space for receiving a measured volume of mastic material prior to any discharge of mastic material.

11. The applicator tool of claim 10, further comprising compression means for applying pressure to said mastic material in said applicator head for driving mastic material through said plurality of nozzle bores.

12. The applicator tool of claim 11, wherein said compression means comprise a compressed air hose connected to said applicator head.

13. The applicator tool of claim 1, further comprising a riveting robot, and connectors securing said radial second guide to said riveting robot.