DEVICE AND METHOD FOR PRODUCING A TEST ADHESIVE STRIP ROLL FOR VISUALIZING AIR CURRENTS

RELATED APPLICATIONS

This application claims the benefit of the filing date of United States Provisional Patent Application No. 60/745,097 filed April 19, 2006, and of the German Patent Application No. 10 2006 018 133.6 filed April 19, 2006, the disclosures of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a device and a method for producing a test adhesive strip roll, on which a test adhesive strip is wound, on whose surface multiple thread pieces are implemented, which project beyond an edge of the test adhesive strip.

TECHNICAL BACKGROUND OF THE INVENTION

A test adhesive strip wound on a test adhesive strip roll of this type may be used in particular for visualizing air currents on surfaces of a model to be tested.

There are various possibilities for visualizing air currents on model surfaces in wind tunnels. One technique is the use of threads on the surface which is to be examined. The behavior of the threads provides a rapid overview of the air current conditions in the region examined. By illumination with UV light, white threads or threads made of fluorescent synthetic material are very well visible, so that these measurements may be documented using a video camera. The threads are typically glued onto the model surface, either in sequence using adhesive material droplets or using adhesive strip pieces, or they are stuck onto one side of an adhesive strip before the adhesive strip is attached to the model. In high-velocity areas, for example, the technique in which the threads are attached individually is used, because adhesive strips may not interfere with the surface of the model. In lower-velocity areas, however, preconfigured adhesive strips having threads may be used. The adhesive strips having the threads are cut to length by hand, which is time-consuming and cumbersome.

Documents WO-A-2005/022109 and US-A-4 410 382 each disclose a method of producing adhesive strips with threads.

There may be a need to produce a possibility for providing threads for visualizing air currents, in such a way that they may be used rapidly and efficiently in the visualization of air currents on surfaces of a model.

The achievement of the stated need may be inferred from the independent claims 1 and 6. Embodiments of the present invention are specified in the subclaims.

PRESENTATION OF THE INVENTION

The device according to the present invention for producing a test adhesive strip roll, on which a test adhesive strip is wound in one piece, on whose surface multiple thread pieces are implemented, contains a thread access unit having a thread roll, on which a thread is wound in one piece, a thread cutting unit, which cuts a thread supplied by the thread access unit from the thread roll into the thread pieces at a predetermined length, an adhesive strip unrolling unit, which supplies an adhesive strip, an assembly unit, which applies the thread pieces to the surface of the supplied adhesive strip at a predetermined angle and a predetermined distance from one another, so that a free end of each thread piece projects away from the edge of the adhesive strip, an unrolling unit, which unrolls a cover strip onto the surface of the adhesive strip and the thread pieces applied thereto to form a test adhesive strip, which comprises the adhesive strip, the cover strip, and the interposed thread pieces, and a rolling unit, on which the test adhesive strip is rolled up.

The distance of the thread pieces to one another may always be constant.

The thread pieces may be located perpendicular to the longitudinal direction of the adhesive strip on a surface thereof and extend beyond the edge of the adhesive strip.

According to an embodiment of the present invention, the cover strip is a foam film.

According to another embodiment, the cover strip is easily removable from the test adhesive strip, without the thread pieces being damaged and/or detached from the adhesive strip.

The method according to the present invention for producing the above-mentioned test adhesive strip roll has the following steps:

Supplying a thread, which is wound on a thread roll, by a thread access unit, cutting the supplied thread into thread pieces of a predetermined length by a thread cutting unit, supplying an adhesive strip by an adhesive strip unrolling unit, applying the cut thread pieces at a predetermined angle and a predetermined distance from one another to the surface of the adhesive strip by an assembly unit, so that a free end of a thread piece projects away from the edge of the adhesive strip, unrolling a cover strip onto the surface of the adhesive strip and the thread pieces attached thereto, in order to form the test adhesive strip, which contains the adhesive strip, the cover strip, and the interposed thread pieces, and rolling up the test adhesive strip on a rolling device, such as a spool.

According to an embodiment of the present invention, the individual steps are performed automatically, so that the test adhesive strips may be produced and wound up on the rolling device continuously.

A test adhesive strip produced by the method described above and/or the device described above may be used for visualizing air currents on surfaces by unrolling the test adhesive strip rolled up on the rolling unit, removing the cover strip, and sticking the test adhesive strip having the threads to the surface on which the air currents are to be visualized.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred exemplary embodiment of the present invention is described in the following with reference to the attached drawing.

• Figure 1 shows a schematic partial view of a device for producing the test adhesive strip according to the preferred exemplary embodiment from the side;
• Figure 1a shows a schematic view to illustrate the movement capability of a robot unit shown in Figure 1;
• Figure 2a-2c show a side, front, and top view of a thread access unit and a thread cutting unit from Figure 1;
• Figure 3 shows a side view of pincers for gripping and holding a thread;
• Figure 3a shows an interior view of the left pincer leg;
• Figure 3b shows an interior view of the right pincer leg;
• Figure 4 shows a side view of the thread cutting unit from Figure 1;
• Figure 4a shows a top view of the thread cutting unit from Figure 1;
• Figure 5 shows a schematic configuration of the device from Figure 1 from the front;
• Figure 6 shows an assembly unit having the pincers shown in Figure 3;
• Figure 7 shows a partial view of a model having an adhesive strip having threads;
• Figure 8 shows a partial view of a mounting plate of the working area of the device from Figure 1;
• Figure 9 shows a partial view of a base frame of the device from Figure 1 from the front;
• Figure 10 shows a gripper of the assembly unit shown in Figure 6;
• Figure 11 shows a rolling device for a test adhesive strip;
• Figure 12 shows a partial view of the working area of the device from Figure 1;
• Figure 13 shows a more detailed view of the rolling unit shown in Figure 12; and
• Figure 14 shows a partial view of the device according to the preferred exemplary embodiment, which illustrates the cover strip unrolling unit.

In the following, identical reference signs are used to identify identical or corresponding components in the different views.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION

Figure 1 shows a partial view of a first exemplary embodiment of a device according to the present invention.

The device according to the present invention, as it is described in the following, is designed to glue thread pieces automatically to adhesive strips and to apply a cover film thereto to form a test adhesive strip, which is wound up automatically on a test adhesive strip roll.

As shown in Figure 1, the device contains a stand 1, on which a stand plate 2 is mounted. A robot unit 31 is mounted on the stand plate 2. The robot unit contains a robot base stand 31a, which is mounted fixed on a surface of the stand plate 2, a robot turntable 31 b, a robot rocker 31 c, a robot arm 31d, a robot hand 31e, and a robot flange 34a. The individual movement directions of the robot elements are illustrated in Figure 1a.

As shown in Figure 1, a thread access unit 4 and a thread cutting unit 5 are located neighboring the robot unit 31 on the surface of the stand plate 2, which are described in greater detail with reference to Figures 2a, 2b and 2c.

Furthermore, a mounting plate 6 extends from the stand plate 2, which may be made of metal, for example, and contacts a side of an adhesive strip which is supplied by an adhesive strip unrolling unit (not shown). The mounting plate 6 is connected to a frame 25, for example, which has rolls 9, which are cushioned using a 1 cm thick plastic foam mat, for example.

The mounting plate 6 preferably always has the same distance to the robot base stand 31a.

The robot unit 31 is mounted fixed on a rear area of the stand 1 and is equipped with a pneumatically operated gripper 50, which is attached to the robot flange 34a using a gripper flange connection unit. For example, pincers 91 made of aluminum, as shown in Figure 3, are attached to the jaws of the gripper 50.

As shown in Figure 1, the stand 1 is supported on wheels 60 and thus movable. Alternatively, the stand 1 may be connected fixed to the floor.

Figure 2a illustrates the thread access unit 4 and the thread cutting unit 5 from Figure 1.

The thread access unit 4 contains a thread roll 12, which is mounted on a thread holder stand 10 so it is rotatable. A thread 11 is wound in one piece on the thread roll 12. As the thread 11 is unwound, the end of the thread runs through a thread tube 13. The thread end area 19 of the thread 11 projecting out of the thread tube 13 is supplied to the thread cutting unit 5. The thread access unit 4 is positioned on the stand plate 2 of the stand 1 in such a way that the gripper 50 of the robot unit 31 may access it easily.

Figure 2b shows a front view of the thread access unit 4 and Figure 2c shows a top view of the thread access unit 4 and the thread cutting unit 5.

Figure 3 illustrates pincers 91 attachable to the gripper 50 for gripping a thread end area 19 of the thread 19, which projects out of the thread tube 13, as shown in Figure 2, and for supplying the thread end area 19 to the thread cutting unit 5 shown in Figure 2.

Figures 3a and 3b show an interior view of a left pincer leg 92 and a right pincer leg 93, respectively. According to the preferred exemplary embodiment, the pincer legs 92, 93 are movable in relation to one another to be able to grip the thread end 19.

As described above, the pincers 91 are connected via a gripper flange connection unit to the robot flange 34a. The robot is capable of activating the pincer legs 92, 93 independently of one another. Furthermore, it is possible that the pincer legs 92, 93 are pre-tensioned, for example.

Figure 4 shows a side view of the thread cutting unit 5 and Figure 4a shows a top view of the thread cutting unit 5. The thread cutting unit 5 is attached to the stand 1 from Figure 1.

As shown in Figure 4a, a cutter 16, which is pre-tensioned by a spring, strikes an anvil 14, which is positioned diametrically opposite, by which the thread 11, which is located in a free space 18, is disrupted (cut). The cut thread, i.e., the thread piece 15, is then held by a thread clamp.

The robot unit 31 is programmed in such a way that the pincers 91 grip the thread which projects out of the thread tube 13 and guide the thread 2 cm in the horizontal direction, for example, to the free space 18 of the thread access unit 5. While the pincers 91 hold the thread 11, a relay is actuated using a robot controller (not shown), which first triggers cutting of the thread and then causes the clamping device of the thread cutting device 5 to open. Next, the robot unit 31 positions the pincers 91, which still grip the thread piece 15, over the mounting plate 6 in such a way that the pincers 91 may be opened, and the thread piece 15 falls onto a desired position of an adhesive strip, whose adhesive side lies facing up on the mounting plate 6 and is supplied continuously, for example.

The procedure of gripping the thread 11, cutting the thread 11, applying the thread piece 15, and pressing the thread piece 15 onto the adhesive strip is automatically performed repeatedly by the robot unit 31, so that multiple thread pieces 15 on an adhesive strip, which is located on the mounting plate 6, may be glued onto a surface of the adhesive strip.

Figure 5 shows the construction of the entire device from Figure 1.

Figure 6 shows an assembly unit for applying thread pieces to an adhesive strip having a gripper 50, which is attached to the robot flange 34a. Furthermore, the pincers 91 having their pincer legs 92, 93 are mounted on the gripper 5. The robot flange 34a is supplied with energy and control information via current and control cable 51 to open and close the pincer legs 92, 93 and/or rotate the gripper 50 in various directions, as shown in Figure 1a.

Figure 7 shows a partial view of a model wing 7, on whose surface air currents are to be examined.

The thread pieces 8 are spaced uniformly, for example, and extend over equal lengths essentially perpendicularly to the longitudinal axis of the adhesive strip 24. The free ends of the thread pieces 8 project away from the adhesive strip 24 and may be engaged by an air current, the free end of the thread pieces 8 orienting in accordance with the air current, by which it is possible to visualize the air current. The thread pieces may extend at various angles and have different distances to one another.

Figure 8 shows a partial view of the mounting plate 6, which is connected fixed to the working area of the robot unit 31.

Figure 9 shows a partial view of the stand 1, on which a robot unit 31 is mounted.

Figure 10 shows the gripper 50 from Figure 6, fastening areas 52 for the pincer legs 92, 93 being illustrated. The gripper 50 is attached to the robot flange 34a as described above.

Figure 11 shows a rolling device 60 in the form of a spool 27. The rolling device is used for rolling up the test adhesive strip (not shown), which is formed by the adhesive tape strip 24, the thread pieces 15 applied thereto, and a foam film 28 applied thereto, as shown in Figure 12. The rolling device 60 may also have a form other than a spool to store the test adhesive strip. The test adhesive strip is wound in one piece onto the spool 27.

Figure 12 shows a partial view of the area of the mounting plate 6 of the device from Figure 1.

The left half of Figure 12 shows an adhesive tape unrolling unit 26, which supplies the adhesive tape strip 24 continuously in a working area 61, which is implemented as a support plate, for example. The adhesive side of the adhesive tape strip 24 is directed upward, so that thread pieces 15 are allowed to fall from the pincers 91 of the gripper 50 which is attached to the robot flange 34a, so that the adhesive strip 24 having the thread pieces 8 shown in Figure 7 is formed. This adhesive tape strip 24 having the thread pieces 15 applied thereto is guided to the spool 27 and wound together with the foam film 28, which is also supplied, onto the spool 27 in such a way that a test adhesive strip results, comprising the adhesive tape strip 24, the thread pieces 15 applied thereto, and the foam film 28 applied thereto. The foam film 28 is used for the purpose of protecting the individual layers rolled onto the spool 27 from sticking together, and to ensure uniform winding independently of the increasing radius. The foam film 28 may be removed easily from the adhesive tape 24 and the thread pieces 15, without damaging the thread pieces 15.

The spool 27 and the adhesive strip unrolling unit 26 are separately drivable via a motor, for example, to unroll the adhesive strip 24 from the adhesive strip unrolling unit 26 and/or to wind the adhesive strip 24 together with the thread pieces 15 applied thereon onto the spool 27. A drive of the adhesive tape unrolling unit 26 is not necessary according to another exemplary embodiment.

Figure 13 shows a partial view of the device according to the present invention, in which the spool 27 is more clearly recognizable.

Figure 14 shows a partial view of the device according to the present invention, in which a foam film unrolling unit 29 is shown.

In the following, the method for producing the test adhesive strip, as discussed above, is summarized.

The robot unit 31 is programmed in such a way that it grips the thread of the thread roll 12 hanging out of the thread tube 13 using the pincers 91 of the gripper 50, then draws the thread 11 over a length of 2 cm, for example, horizontally over the slot 18 of the thread cutting unit 5. While the pincers 91 still hold the thread 11, a relay is switched via a controller of the robot unit 31, which first triggers cutting of the thread 11 into thread pieces 15, and then opens the clamping device of the thread cutting unit 5. In the next work step, the robot unit positions the pincer 91 still grasping the thread pieces 15 over the support plate 61 in such a way that the pincers may open and eject the thread pieces 15 at an angled position to the support plate 61, having one end of the thread 15 contacting the adhesive tape strip 24, onto the desired position and then press it into place.

The beginning of the adhesive tape strip 24, which was drawn out of the adhesive strip unrolling unit 26, and the foam film 28, which was simultaneously drawn from an unrolling device 29, are fixed on the spool 27 in such a way that the adhesive tape strip 24 and the foam film 28 are unrolled from their respective sources as the spool 27 rotates and rolled onto the spool 27. Simultaneously, the adhesive tape strip 24 is drawn over the working area of the small support plate 61. With the winding, the mechanism draws the adhesive tape strip 24 over the working area, so that the next thread piece 15 may be stuck on by the pincers 91 at an exactly maintained distance.

The requirement that the distance between the glued thread pieces 15 is to remain constant is implemented by an algorithm, using which the steps to be set on a stepping motor (not shown) may be calculated. When deriving this algorithm, for example, it is taken into consideration that the radius of the test adhesive strip (adhesive tape strip/thread pieces/foam film 24/8/28) composite wound on the spool 27 becomes larger with each rotation.

A result of the procedure described above is a spool 27 which is wound with an adhesive tape strip/thread piece/foam film 24/8/28 composite. For visualizing air currents in wind tunnel tests, for example, the required test adhesive strips of the equipped thread pieces 15 are uncoiled from the foam film 28 of finished wound spool 27 at the required length and stuck onto a model surface.

Although the present invention was described above with reference to a preferred exemplary embodiment, it is obvious that modifications and alterations may be performed without leaving the scope of protection of the present invention.

For example, it is possible to apply the thread pieces to the adhesive tape 24 using varying spacing. Furthermore, as an alternative to a foam film, another suitable cover material may also be used, which may be detached easily from an adhesive surface of the adhesive tape, without damaging the thread pieces applied thereto. Furthermore, different types of thread (thread brand, thread thickness, thread color) may be used.

Reference numerals

1

stand

2

stand plate

4

thread access unit

5

thread cutting unit

6

mounting plate

7

model wing

9

rolls

10

thread holder stand

11

thread

12

thread roll

13

thread tube

15

thread pieces

19

thread end area

31

robot unit

31a

robot base stand

31b

robot turntable

31c

robot rocker

31d

robot arm

31e

robot hand

34a

robot flange

91

pincers

92, 93

pincer legs (left, right)

94

groove

27

spool

28

foam film

50

gripper

51

cable

60

rolling device