DE10244964B4 - Device and method for automatic loading of clamping magazines with workpieces - Google Patents

Abstract

Device for automatic loading of clamping magazines (6) with workpieces (3) with a gripper (2) for receiving, holding and, in clamping position, dispensing at least one workpiece (3), and a handling device (1) for moving the gripper (2) in a first direction and then in a second direction in the clamping position of the workpiece (3), characterized by an optical sensor (17) for detecting the clamping position, wherein the sensor (13) in or on the gripper (2) is arranged mitbeweglich and wherein a movement of the handling device (1) is controlled based on the sensor signals.

Description

The invention relates to a device and a method for automatic loading of clamping magazines with workpieces.

The technical field of application of the invention is the automatic assembly of tolerance-loaded clamping magazines with workpieces using a handling device. Such clamp magazines are used, for example, in the electroplating and / or electrochemical coating of workpieces. They are then referred to as feed or galvanizing racks.

In galvanic plants, workpieces to be electroplated or electrochemically coated are mounted on feed racks. The workpieces are preferably small and medium sized parts, d. H. around parts that have an extension between 1 mm and 1 m.

• 1. Festbinden der zu beschichtenden Werkstücke auf den Beschickungsgestellen mittels Draht oder geeigneten selbstsperrenden Schellen aus Kunststoff.
• 2. Aufstecken der zu beschichtenden Werkstücke auf abstehende Haltestifte oder Einklemmen der zu beschichtenden Werkstücke zwischen abstehenden Haltestiften. Bei dieser Ausführungsvariante der Beschickungsgestelle handelt es sich somit um Klemm-Magazine.
• 3. Einsatz schwenkbarer Haken, die an dem Beschickungsgestell befestigt sind, um einen sicheren Transport der Werkstücke zu gewährleisten.

The arrangement of the workpieces on the feed racks, the number of pieces to be coated workpieces is increased and significantly improved bath utilization. For attaching the workpieces on the feed racks, there are three different approaches:

• 1. Tying the workpieces to be coated on the feed racks by means of wire or suitable self-locking clamps made of plastic.
• 2. Placing the workpieces to be coated on protruding retaining pins or pinching the workpieces to be coated between protruding retaining pins. In this embodiment, the feed racks are thus clamping magazines.
• 3. Use of pivoting hooks, which are attached to the loading frame to ensure safe transport of the workpieces.

Previously used in the galvanizing clamping magazines 6 (please refer 1 ) usually consist of a rectangular frame 20 with evenly spaced arranged transverse webs between them 8th that with evenly spaced holes or protruding pins 5 are provided. Be holding pins 5 used for clamping the workpieces, these are usually on both sides of the transverse webs 8th arranged to clamp the largest possible number of workpieces can.

The well-known clamping magazines run through in vertical suspension the individual baths and stations of the galvanization and thus allow a running along the transverse webs series suspension of the workpieces to be coated.

• a) Haltestifte können verbogen sein
• b) Haltestifte können fehlen
• c) Die Fertigungstoleranzen der Magazine liegen im Zehntelmillimeter oder Millimeterbereich
• d) Die Klemm-Magazine sind häufig im Hinblick auf elektrische Leitfähigkeit zwischen Werkstück und Magazin, auf optimalen elektrischen Feldverlauf im Galvanisierungsbecken, auf optimales Abfließen der Galvanisierungsflüssigkeit und auf optimalen Halt der Werkstücke konstruiert und dadurch meist sehr komplex.

Significant features of Klemm magazine are:

• a) Holding pins can be bent
• b) Holding pins may be missing
• c) The manufacturing tolerances of the magazines are in tenths of a millimeter or millimeter range
• d) The clamping magazines are often designed with regard to electrical conductivity between the workpiece and magazine, optimal electrical field profile in the galvanizing tank, optimal flow of the galvanizing liquid and optimum support of the workpieces and thus usually very complex.

Here, as below, the following definitions are to be used: compensatory movement Under a compensation movement is a movement movement of the gripper relative to the handling direction or a movement of the clamping Magazine relative to the holder of the clamping Magazine can be understood. She is going through the Use of a mechanical compliance with Help of springs or elastomers allows and is used to compensate for position errors the handling device. loading rack A loading rack is a rack on which to be electroplated or electrochemically layered workpieces are attached. It serves to charge a galvanizing or coating plant with workpieces. Galvanisierungsgestell see loading frame retaining pins Retaining pins are pins that are used to Clamp workpieces. Clamp magazine A clamping magazine is a magazine, which with several workpieces can be equipped the workpieces with the help of retaining pins be clamped. A clamping magazine is an embodiment of a Beschickungsge stells. terminal slot A terminal consists of at least two Holding pins and serves to workpieces terminals. clamping position Under a clamping position becomes a position with respect to the frame coordinate system ver stood on the workpiece to be clamped be trapped between two retaining pins can. terminal support Under a Klemmunterstützung are all Measures understood, the clamping of To facilitate workpieces. Such measures are z. B. a secondary movement when Klem a spreading of the retaining pins or the Use of a lubricant when clamping. reference stop A reference stop is a mechanical stop blow that in contact with one of the two Retaining pins is used for referencing. secondary movement Under a secondary movement becomes a move understood that of another movement is superimposed, without this we we is considerably influenced. When clamping is as Secondary movement a rotation or vibration of the gripper or the frame running to the occurring frictional forces during clamping to reduce.

Although there have been attempts in the past to automate the loading of clamping magazines, however, the attachment of the workpieces to the clamping magazine is usually still manual due to the manufacturing inaccuracies and the often very complex structure of the clamping magazines.

On the one hand, a method for automatic loading of clamping magazines has been developed, which is characterized in that the objects to be treated are attached by means of wire to the clamping magazine ( DE 198 22 786 A1 On the other hand, a method has been developed for automatic loading of clamping magazines, which is characterized in that clamping magazines and workpieces made of plastic are used, which are connected to each other by means of a sprue or connecting web of the workpiece ( DE 198 51 130 A1 ).

The publication US 3,824,674 A discloses an automatic loading device in which a workpiece is automatically inserted into an opening by means of a gripper. In this case, a compliance is arranged between the gripper for the workpiece and the handling device for the gripper, so that gripper and handling device are mutually movable. When inserting the workpiece, the workpiece is now deliberately placed next to the actual position on the substrate and then moved until it is inserted into the associated opening.

The publication DE 100 12 081 C2 describes a method and a device for automatically positioning a component at a joining position of a mounting plane by means of a gripper, which is adjustable by means of a gripper drive and a Feinpositionierantriebs a handling device (robot tool), and by means of an optical measurement and image processing system for determining the joining position and the component position of the gripper held component. In this case, the joining position and the component position or a reference position related to the component are sequentially imaged and measured by a tool measuring objective of the optical measuring system. In a memory stored images of the measured positions are brought into agreement by the image processing system and thereby obtained a manipulated variable for a position correction to be performed by the gripper drive.

The publication DE 33 10 191 A1 discloses a gripper for industrial robots, wherein the gripper upper part is mounted radially floating by means of balls on a lower part in the gripper axially guided support member. The axial and radial movements occurring during assembly are recorded and used to correct the movement.

The publication US 4 609 325 A describes a robot hand for inserting a bolt into a borehole having an arm connected to the robot, further comprising an end piece for holding the bolt and connecting elements on the arm, the end piece allowing free movement of the end piece with respect to the arm and ensures a self-centering of this tail. The connecting elements are magnetized in the direction of their axis and are located between the arm and the end piece, so that they attract each other, being separated by balls from each other.

The publication DE 3 641 368 A1 describes a storage for a gripper. The gripper has at the end of his working arm two spaced-apart plates for a resiliently mounted on rolling elements receiving disc, which is provided with a neck ring for the gripper and thus hooked by the working arm averted plate. As a result, a storage of the gripper can be made simpler and more mobile.

The object of the invention is therefore to provide a device for automatic assembly of clamping magazines with workpieces available that allows lower operator costs, lower assembly times, a konsatnte and better quality of the assembly and a process control. A further object of the invention is to provide a method by which clamping magazines can be automatically loaded with workpieces, the low investment costs, little effort when switching from manual to automatic operation and vice versa and no additional fastening aids for the workpieces requires.

These objects are achieved by the device according to claim 1 and the method according to claim 21. Advantageous developments of the device according to the invention and of the method according to the invention are given in the respective dependent claims.

The device according to the invention for automatic loading of clamping magazines ( 6 ) with workpieces has a gripper for receiving, holding and, in clamping position, dispensing at least one workpiece and a handling device for moving the gripper in a first direction and then in a second direction in the clamping position of the workpiece. The inventive device is further characterized by an optical sensor for detecting the clamping position, wherein the sensor is arranged in or on the gripper mitbeweglich and
wherein a movement of the handling device is controlled based on the sensor signals.

In the invention, a handling device to which the gripper for the workpiece is attached, for example, a robot arm is moved to an absolute position.

Since the pins of the clamping magazines which define the clamping position are often severely bent or otherwise displaced, a mechanical compliance in the gripper, the robot arm or between gripper and robot arm or on the side of the clamping magazines or their holder between them be provided so that the robot arm can be moved to a defined position and yet the workpiece can be pushed into the slightly faulty positioned clamping position.

Advantageously, a reference stop can also be used for this purpose.

Alternatively, it is also possible, although to move the robot arm to an absolute predetermined position, but to detect the achievement of the clamping position via a force torque sensor and thus additionally controlling the robot arm. The workpiece can then be brought exactly positioned in the clamping position.

The robot arm can also be moved to a position that is detected by a sensor. For this purpose, a sensor is provided to detect the clamping position, for example, the position of the retaining pins.

Of course, a combination of all these possibilities of the invention is included, since the combination of an optimal Einjustierung of the workpiece in the clamping position is possible.

A further advantageous embodiment of the invention is characterized in that a controller is provided to control the movement of the handling device in the first direction, to the first position and / or in the second direction.

A further advantageous embodiment of the invention is characterized in that at least one stop is arranged in or on the handling device, the magazine holder, the gripper and / or the magazine, the workpiece when moving the handling device in the first direction or to the first position with respect to the plane perpendicular to the second direction in the clamping position.

A further advantageous embodiment of the invention is that in or on the handling device, the magazine holder, the gripper and / or the magazine at least one stop is arranged, the workpiece with respect to the plane perpendicular to the second direction upon movement of the handling device in the second direction in the clamping position or blocks the movement of the handling device when the workpiece is not in the clamping position relative to the plane perpendicular to the second direction.

A further advantageous embodiment of the invention is characterized in that the workpiece itself serves as a vertical reference stop.

• 1. Geringere Betreiberkosten, da das manuelle Bestücken durch einen hohen Personaleinsatz mit einem hohen Krankenstand gekennzeichnet ist.
• 2. Geringere Bestückungszeiten.
• 3. Konstante und bessere Qualität der Bestückung.
• 4. Möglichkeit einer Prozesskontrolle.

The advantages over manual loading of clamping magazines are:

• 1. Lower operator costs, as manual loading is characterized by a high workforce with a high sickness absence.
• 2. Lower loading times.
• 3. Constant and better quality of assembly.
• 4. Possibility of a process control.

• 6. Geringe Investitionskosten, da die selben Klemm-Magazine wie beim manuellen Bestücken verwendet werden können.
• 7. Geringer Aufwand beim Umstellen von manuellem auf automatischen Betrieb und umgekehrt, da an den bisher verwendeten Klemm-Magazinen festgehalten wird.
• 8. Außer dem Klemm-Magazin werden keine zusätzlichen Befestigungshilfen wie z. B. Draht oder Schellen sowie keine weiteren Bearbeitungsschritte wie z. B. das Abtrennen der Werkstücke vom Klemm-Magazin benötigt.

The advantages over the known methods for automatic loading of clamping magazines are:

• 6. Low investment costs, since the same clamping magazines can be used as with manual loading.
• 7. Little effort when switching from manual to automatic operation and vice versa, as is held on the previously used terminal magazines.
• 8. Except the clamping magazine no additional fastening aids such. B. wire or clamps and no further processing steps such. B. the separation of the workpieces from the clamping magazine needed.

In the following, some examples of devices and methods will now be described.

Show it

1 a clamp magazine;

2 a basic scheme of a procedure;

3 the conditions for successfully populating a clamp magazine;

4 , States and state transitions during clamping without additional reference stop or with vertical reference stop;

5 an illustration of the individual states during clamping without additional reference stop or with vertical reference stop;

6 States and state transitions when clamping based on a horizontal reference stop;

7 , a representation of the individual states when clamping based on a horizontal reference stop;

8th , States and state transitions when clamping based on a sensor for detecting the retaining pins;

9 Representation of the individual states during clamping based on a sensor for the detection of the retaining pins.

10 Different referencing types.

11 Variants when combining the translatory compensatory movements of gripper and clamping magazine;

12 Variants when combining the rotary compensatory movements of gripper and clamping magazine;

13 Conditions of clamping using a Z compensation that responds to a force F _Z that is greater than the required clamping force F _terminals ;

above: Clamping successful,
below: collision.

Condition I:
Gripper is located above the retaining pins.

Condition II:
Workpiece touches one or both retaining pins.

Condition III:

above: workpiece was clamped correctly,
bottom: when lowering the handling device, the Z compensation has retracted due to the collision of workpiece and retaining pin.

14 Conditions of clamping using a Z compensation that responds to a force F _Z less than the required clamping force F _terminals ;
above: clamping process completed,
bottom: Gripper tries to clamp next to the retaining pins.

Condition I:
Gripper is located above the retaining pins.

Condition II:
Handling device has lowered slightly

above: workpiece touches the retaining pins

Condition III:
Handling device has lowered further, top: Z-compensation moves in due to the frictional forces between workpiece and holding pins.

Condition IV:
Handling device has lowered to the final position,

above: workpiece was clamped correctly,
bottom: Z compensation has not retracted, the workpiece has not been clamped correctly;

15 Significance of the output signals of Z-balancers connected in series with different actuating force;

16 Variants when combining the secondary movement when gripping the gripper and clamping magazine;

17 Possibilities for spreading the retaining pins;

18 Variants when combining the collision protection types of gripper and clamping magazine;

19 Possible grip types of a slim workpiece;

20 Possible types of rotation of a workpiece;

21 Device for automatic placement of clamping magazines with workpieces characterized in that the positions of the terminal locations are stored as absolute positions and can be done without reference stop or vertical reference stop, the clamping magazine is firmly clamped and a compensating movement between gripper and handling device takes place ;

22 Apparatus for automatic placement of clamping magazines with workpieces characterized in that the positions of the terminal locations are stored as absolute positions and can be done without reference stop or vertical reference stop, the clamping magazine is firmly clamped, a compensating movement between gripper and handling device takes place and a vibrator is used for clamping support;

23 Device for automatic placement of clamping magazines with workpieces characterized in that the positions of the terminal stations are stored as absolute positions and without Reference stop or with vertical reference stop is sufficient, with the clamping magazine is firmly clamped, a compensating movement between the gripper and handling device takes place and the clamping support the workpiece is rotated;

24 Apparatus for automatic placement of clamping magazines with workpieces characterized in that the positions of the terminal locations are stored as absolute positions and can be done without reference stop or vertical reference stop, the clamping magazine is firmly clamped, a compensating movement between gripper and handling device takes place , and collision protection is used;

25 Device for automatic assembly of clamping magazines with workpieces, characterized in that the positions of the terminal stations are stored as absolute positions and can be done without reference stop or with a vertical reference stop, wherein the clamping magazine is movably clamped in the XY direction and a compensation movement between Gripper and handling device takes place;

26 Device for automatic assembly of clamping magazines with workpieces, characterized in that the positions of the terminal stations are stored as absolute positions and can be done without reference stop or with a vertical reference stop, wherein the clamping magazine is movably clamped in the XYZ direction and a compensation movement between Gripper and handling device takes place;

27 Device for automatic loading of clamping magazines with workpieces, characterized in that the positions of the terminal locations are stored as absolute positions and a horizontal reference stop is used, which approaches the holding pins in the process in the direction of the X-axis, the clamping magazine fixed is clamped and a compensation movement between gripper and handling device takes place;

28 Device for automatic loading of clamping magazines with workpieces, characterized in that the positions of the terminal stations are stored as absolute positions and a horizontal reference stop is used, which approaches the holding pins upon opening of the gripper, wherein the clamping magazine is firmly clamped and a Compensation movement between gripper and handling device takes place;

29 Device for automatic loading of clamping magazines with workpieces, characterized in that the positions of the terminal locations is determined by means of a sensor from the position of the retaining pins, wherein the clamping magazine is firmly clamped and no compensation movement between gripper and handling device takes place;

30 Device for automatic loading of clamping magazines with workpieces, characterized in that the positions of the terminal locations is determined by means of a sensor from the position of the retaining pins, wherein the clamping magazine is firmly clamped and a compensation movement between gripper and handling device takes place;

31 an explanation of the symbols used in the figures for joints; and

32 an explanation of the other symbols used in the figures.

Here, as in all figures, the following reference numerals denote the elements explained below:

LIST OF REFERENCE NUMBERS

1

a handling device;

2

a gripper;

2a

a jaw;

3

a workpiece;

4

a clamping position;

5

a retaining pin;

6

a clamp magazine;

7

a holder of the clamping magazine;

8th

a crossbar;

9

a planar joint;

10

a firm clamping;

11

a vibrator;

12

a collision protection;

13

an X compensation (= displacement in the direction of the X axis)

14

a Y-compensation (= displacement in the direction of the Y-axis),

15

a γ compensation (= rotation about Z axis)

16

a reference stop;

17

a sensor;

18

a suspension;

19

a rack pin;

20

a frame;

21

a Z-compensation (= displacement in the Z-axis direction);

22

a second gripper;

23

a wedge;

24

a force-moment sensor;

25

a connection rod;

26

an α-compensation;

27

a β-balance;

28

an α, β, γ compensation.

With the invention it is possible by means of a handling device 1 a clamping magazine 6 as for example for electroplating and / or for electrochemical coating of workpieces 3 is used, with workpieces 3 to equip automatically. This is exemplary in 2 shown. 2 shows no device according to the invention, but is helpful for their understanding. Like the workpieces 3 in the gripper 2 reach, is not the subject of the invention, since the gripping of individual workpieces 3 already state of the art.

The single workpiece 3 Which = 0 at the position (X _W Y _W Z _W) (t = 0) is located at the time t, is of the handling device 1 to the clamping position (X _W Y _W Z _W) (t = t _K) = (X _K Y _K Z _K) at time t = t _K conveyed, see 3 , For a detailed description of the determination of the clamping position and the conditions when a clamping can take place successfully, reference is made to the later explanations.

The automatic loading of clamping magazines with workpieces according to the invention is thus based on a reliable determination of the clamping position z. B. by reference stop 16 or sensors 17 , wherein the horizontal positional deviation between the workpiece 3 and the respective slot in the first case by a mechanical compliance 13 - 15 . 21 . 26 - 28 if necessary between grippers 2 and handling equipment 1 and preferably between clamping magazine 6 and bracket 7 of the clamping magazine 6 takes place, while in the second case the clamping position by means of sensors 17 is determined. A combination of the second method to the first method for determining the clamping position is also possible. Come in determining the clamping position sensors 17 used, so it can also be a check whether all the retaining pins 5 on the clamping magazine 6 available.

The mechanical compliance 13 - 15 . 21 . 26 - 28 Depending on the version, it can translate into a translatory one 13 . 14 . 21 and / or rotational 26 - 28 Lead compensating movement. Becomes a Z-compliance 21 so it can be done using a sensor 17 also the success or failure of the clamping process can be determined.

Clamping of workpieces 3 Optionally by reducing the friction by a secondary movement when clamping, by spreading the retaining pins 5 and / or simplified by the use of lubricants. The clamping process can be prevented by collision protection 12 between grapple 2 and handling equipment 1 and / or between clamp magazine 6 and rack mount 7 additionally secured.

• 1. Es wird ohne zusätzlichen Referenzanschlag oder unter Verwendung eines vertikalen Referenzanschlags 16 und einer mechanischen Nachgiebigkeit 13, 14 zu abgespeicherten absoluten Positionen verfahren, wobei das Werkstück selbst auch als vertikaler Referenzanschlag 16 benutzt werden kann, 4 und 5. Anstelle der mechanischen Nachgiebigkeit 13, 14 kann auch ein Kraft-Momenten-Sensor eingesetzt werden, mit dessen Hilfe die Werkstückposition nachgeregelt wird. Der Vorteil beim Einsatz eines Kraft-Momenten-Sensors ist, dass von den Haltestiften 5 keine Kraft zum Auslenken eines mechanischen Ausgleichs 13, 14 aufgebracht werden muss.
• 2. Es wird unter Verwendung eines horizontalen Referenzanschlags 16 und einer mechanischen Nachgiebigkeit 13, 14 zu abgespeicherten absoluten Positionen verfahren, 6 und 7.
• 3. Es wird entlang den Klemmplätzen verfahren und die Klemmposition wird mit Hilfe von Sensoren 17 erkannt, 8 und 9. Der Einsatz einer mechanischen Nachgiebigkeit 13, 14 ist optional.

In the 4 to 9 Three different approaches are described, with the 4 to 8th show no devices according to the invention, but are helpful for understanding the invention:
In principle, there are three approaches

• 1. It will be without additional reference stop or using a vertical reference stop 16 and a mechanical compliance 13 . 14 moved to stored absolute positions, the workpiece itself as a vertical reference stop 16 can be used 4 and 5 , Instead of mechanical compliance 13 . 14 It is also possible to use a force / torque sensor with the aid of which the workpiece position is readjusted. The advantage of using a force-moment sensor is that of the retaining pins 5 no force to deflect a mechanical balance 13 . 14 must be applied.
• 2. It is done using a horizontal reference stop 16 and a mechanical compliance 13 . 14 proceed to stored absolute positions, 6 and 7 ,
• 3. It is moved along the terminal locations and the clamping position is determined by means of sensors 17 recognized 8th and 9 , The use of a mechanical compliance 13 . 14 is optional.

The procedure without reference stop in 4 respectively. 5 is only possible with racks that are made with a very small tolerance, as the position errors add up to the next position with each procedure. The workpiece can still be clamped when the distances d ₁ and d ₂ between the axes of rotation of the workpiece and the retaining pins satisfy the following conditions: d ₁ > 0, d ₂ > 0, d ₁ + d ₂ = d retaining _pins , d retaining _pins the distance between the axes of rotation of the retaining pins is, see 3 , The position error of the workpiece 3 opposite the ideal clamping position in the middle of the retaining pins 5 must therefore be smaller than 1 / 2d _{retaining pins} . The position error of a terminal location with respect to its predecessor must therefore be below d _Tol = 1 / 2d _{retention pins} / n, where n is the number of terminal locations that are approached one after the other. For d _{retaining pins} = 12 mm and n = 64 one obtains thus as upper limits for the position deviation of a clamping place opposite its predecessor d _Tol = 0.09375 mm.

In the vertical or horizontal reference stop procedure in 4 to 7 can through the reference stop 16 and the mechanical compliance 13 . 14 of the gripper or the clamping magazine 6 larger position deviations are compensated. However, since the position errors are also added up in this method, the tolerance range to be compensated is easily exceeded even with this procedure.

In the third method, the gripper is referenced 2 at every nth (n> 0) terminal location with the aid of sensors 17 New, 8th and 9 , Referencing is not done on each retaining pin 5 , so can be moved in between either the first or second approach, which leads to a reduction in the process time.

In the 4 to 9 Three methods are shown in 10 compared with regard to process reliability and tolerance compensation.

• – Translatorische Ausgleichsbewegungen
• – Rotatorische Ausgleichsbewegungen

Balancing movements are basically divided into two types:

• - Translational compensatory movements
• - Rotatory compensatory movements

When loading clamp magazines, it is possible that both the gripper 2 as well as the clamping magazine 6 performs a compensatory movement. The combination of the individual compensatory movements results in a large number of possible combinations. In 11 are some of these combinations for translational and in 12 shown for rotational compensatory movements.

Compensation movements in the XY plane are mandatory when clamping with a reference stop. But even with very accurate positioning are XY compliancy 13 . 14 recommended to avoid jamming during clamping.

A yield 21 The Z-direction is primarily used for process monitoring. With the help of a sensor 17 can be checked if the Z compensation 21 when clamping was needed or not. Will Z compensation 21 used, which responds to a force F _Z , which is greater than the required clamping force F _terminals , so a collision can be detected during clamping, 13 , The Z-compensation 21 thus also serves as collision protection 12 , Will Z compensation 21 used, which reacts at a force F _Z , which is smaller than the required clamping force F _terminals , so it can be detected whether a terminal was tried next to the retaining pins or if there are no retaining pins, see 14 , Will Z compensation 21 responding to a force F _Z > F _clamp and a Z compensation 21 , which reacts in series with a force F _Z <F _terminals , the terminals can be completely monitored and at the same time a collision protection 12 will be realized, 15 ,

Rotatory compliances 15 . 26 - 28 , also serve as protection against jamming. Especially with strongly bent pins 5 are rotatory compliances 15 . 26 - 28 , useful.

13 shows various states of clamping using a Z-compensation, which responds to a force F _Z which is greater than the required clamping force F _terminals .

In the upper row is a successful clamping operation and in the lower a collision between the workpiece 3 and holding pin 5 shown. The individual states designate:

Condition I:
Gripper is located above the retaining pins

Condition II:
Workpiece touches one or both retaining pins

Condition III:

above: workpiece was clamped correctly,
bottom: when lowering the handling device, the Z compensation has retracted due to the collision of workpiece and retaining pin.

14 shows different states of clamping using a Z-compensation which responds to a force F _Z which is less than the required clamping force F _clamps ;

above: clamping process completed,
bottom: Gripper tries to clamp next to the retaining pins

Condition I:
Gripper is located above the retaining pins.

Condition II:
Handling device has lowered slightly

above: workpiece touches the retaining pins.

Condition III:
Handling device has continued to lower,

top: Z-compensation is due to the frictional forces between the workpiece and holding pins.

Condition IV:
Handling device has lowered to the final position,

above: workpiece was clamped correctly,
bottom: Z compensation has not retracted, the workpiece has not been clamped correctly.

• – Ausführen einer Sekundärbewegung beim Klemmen
• – Aufspreizen der Stifte 5
• – Reduzierung der Reibung durch Einsatz von Schmiermittel

To reduce the forces during clamping different clamping supports can be used:

• - Perform a secondary movement during clamping
• - spreading the pins 5
• - Reduction of friction by using lubricant

Secondary movements during clamping are subdivided into translatory and rotary secondary movements during clamping. While translational movements are always vibrating movements, rotational movements can be both rotating and rocking movements. Because both the gripper 2 as well as the clamping magazine 6 can perform a secondary movement during clamping, the nine combinations result in 16 , A rotational movement of the frame 7 is usually a swinging motion.

As in 17 pictured, may be the spreading of the retaining pins 5 also done in several ways.

• – Mechanischer bzw. pneumatischer Kollisionsschutz 12 (Funktionsweise eines üblichen Kollisionsschutzes erhältlich für Industrieroboter)
• – Kollisionsschutz 12 durch Überwachung der Prozesskräfte mittels Kraft-Momenten-Sensor.

Since with a Galvanisierungsgestell the possibility exists that individual retaining pins 5 are so bent that a terminal is impossible, is the use of collision protection 12 required. The collision protection 12 can be both between gripper 2 and handling equipment 1 as well as between clamping magazine 6 and bracket 7 of the clamping magazine 6 are located. As collision protection 12 In principle, two versions are conceivable:

• - Mechanical or pneumatic collision protection 12 (Functionality of a conventional collision protection available for industrial robots)
• - collision protection 12 by monitoring the process forces by means of force-moment sensor.

A Z-compliance 21 can also be used as mechanical collision protection 12 serve.

The different variants when combining the collision protection types of gripper 2 and clamping magazine 6 shows 18 ,

In 19 the different types of gripping are shown, like a slender workpiece 3 can be used advantageously. In principle, a distinction is made whether the workpiece 3 is gripped on the end face or on the lateral surface. If gripping on the lateral surface, several gripping points are possible. However, it makes sense to have at least two, because in the grip points then no more moments must be recorded.

In addition to the quality of the handle, the gripping mode primarily influences the possibility of a rotary secondary movement when gripping the gripper 2 can be executed. In 20 are the different rotational secondary movement when gripping the gripper 2 depending on the grip type.

In the following some devices are presented, which are used to automatically load a clamping magazine 6 with a workpiece 3 are suitable.

It is started with devices in which the positions of the terminal stations are stored as absolute positions and get along without a reference stop or with a vertical reference stop.

In an example in 21 , which is not an example of the invention, but may serve to explain individual aspects of the invention, is the clamping magazine 6 firmly clamped. A mechanical compensation 9 is between handling device 1 and grapple 2 realized. The planar joint 9 serves on the one hand to compensate for positional errors in the XY plane and on the other hand it allows a rotational compensation movement to jamming due to bent rods 5 to prevent. The Z-compensation 21 It is mainly used for collision protection, but also for monitoring the clamping process. Since in this example all further clamping supports are dispensed with and for this reason large clamping forces are to be expected, the workpiece becomes 3 at two positions on the lateral surface of the gripper 2 resorted.

In 22 which is not an example of the invention, but may serve to explain individual aspects of the invention, a second example is shown. It corresponds to the first example with the only difference being that it is clamped by a vibrator 11 on the gripper 2 is supported, reducing the frictional forces between workpiece 3 and holding pins 5 entails.

The same applies to the third example in 23 , which is not an example of the invention, but may serve to explain individual aspects of the invention in which a rotary movement of the gripper 2 through the handling device 1 is initiated to reduce the friction forces. In addition to the example shown, it is also conceivable that the rotational movement during clamping by a drive between gripper 2 and handling equipment 1 or in the gripper 2 to realize yourself. In addition to the examples shown, it may also be useful instead of the gripper 2 the frame 7 a rotary or vibrating movement to reduce the frictional forces during clamping, let run.

The fourth example in 24 , which is not an example of the invention, but can serve to explain individual aspects of the invention, substantially corresponds to the first example in 21 , The Z-compensation 21 was however by a collision protection 12 , which is commonly used in welding with the help of industrial robots, replaced by the use of collision protection 12 the safety against collisions is increased. However, it is no longer possible to monitor the clamping process, as with the use of Z-compensation with a sensor. The installation of a collision protection 12 between clamping magazine 6 and bracket 7 of the clamping magazine 6 may also be useful.

In the fifth and sixth examples in 25 respectively. 26 , which are not examples of the invention, but may serve to explain individual aspects of the invention, the translational compensation movement is partially or completely from the frame 7 . 10 , executed. While in 25 the compensation movement in the XY plane of the clamping magazine 6 and in the Z direction from the gripper 2 is executed is in 26 also the yielding 21 in the Z direction between the clamping magazine 6 and the holder 7 of the clamping magazine 6 realized. The rotational compensation movement is in both cases by the gripper 2 executed.

At the following in 27 and 28 illustrated examples, which are not examples of the invention, but may serve to explain individual aspects of the invention, the positioning of the gripper 2 realized via the terminal locations by a mechanical reference stop. It is important to note that the rotational compensatory movement through the planar joint 9 during the referencing is prevented, otherwise there is a twisting of the gripper 2 can come around the z-axis. The rotational compensation movement is desired only during the clamping process.

While referencing in 27 through one on the gripper 2 fixed angle 16 , which is moved in the direction of the x-axis against a retaining pin, will be in 28 the gripper 2 only when opening the gripper 2 put in the right position. The arrangement in 28 allows a spreading of the support rods 5 as clamping support. However, it is important to ensure that the workpiece 3 not too early out of the grab 2 falls. If this is not possible, the spreading can also be achieved by a wedge, which is moved vertically downwards or by a second gripper 2 done with special gripper fingers.

In addition to the two in the 27 and 28 Of course, examples are also corresponding examples 22 and 23 possible in which the clamping is supported by an additional clamping movement. The use of a collision protection 12 as in 24 is just as conceivable as the realization of translational compliance 13 . 14 between clamping magazine 6 and bracket 7 of the clamping magazine 6 as in 25 and 26 ,

In the in the 29 and 30 presented examples, becomes an optical sensor 17 for referencing the gripper 2 used. In 29 is dispensed with any mechanical compliance. This requires a very accurate positioning of the workpiece 3 above the clamping position. Are the retaining pins 5 bent very much, can be a rotational compliance 15 around the Z-axis between gripper 2 and handling equipment 1 be beneficial.

A very robust example shows 30 , despite the sensor-based positioning compensating movements of the gripper 2 allows. Jamming of the workpiece 3 between the retaining pins 5 This makes it extremely unlikely. Furthermore, both the presence of the retaining pins 5 a terminal location by the Referenzierungs sensor 17 as well as the clamping process itself by a Z-compensation 21 built-in sensor to be checked.

In addition to the examples listed further solutions are possible, which reduce the friction forces during clamping by the use of clamping supports. Furthermore, the compensation elements can also be between terminal magazine 6 and bracket 7 of the clamping magazine 6 are located. By installing a collision protection 12 The risk of destruction of components can be further reduced.

31 explains the symbols used in the previous figures for joints.

Joints are used to connect bodies with at least one degree of freedom (displacement or rotation) between the two bodies. Since the representation of the joints in the room is difficult, the in 31 used and partly simplified symbols used.

The origin of the coordinate systems next to the symbols is located in the center of the corresponding joint. The coordinate systems were drawn only for a clearer representation next to the symbols.

In addition to the in 31 The joints shown in FIG 32 illustrated symbols used for elements in the previous figures. These are the symbols for a holder with sensor, a reference stop, a fixed clamping and a collision protection.

Claims (27)

Device for automatic loading of clamping magazines ( 6 ) with workpieces ( 3 ) with a gripper ( 2 ) for receiving, holding and, in clamping position, dispensing at least one workpiece ( 3 ), and a handling device ( 1 ) for moving the gripper ( 2 ) in a first direction and then in a second direction in the clamping position of the workpiece ( 3 ), characterized by an optical sensor ( 17 ) for detecting the clamping position, wherein the sensor ( 13 ) in or on the gripper ( 2 ) is movably arranged and wherein a movement of the handling device ( 1 ) is controlled on the basis of the sensor signals. Device according to the preceding claim, characterized in that the movement of the handling device ( 1 ) is controlled in the first direction due to the sensor signals. Device according to one of the preceding claims, characterized by a magazine holder ( 7 ) for holding the clamping magazine ( 6 ), as well as at least one mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) to allow a compensation movement between the clamping magazine ( 6 ) and the magazine holder ( 7 ) in a plane perpendicular to the second direction, between the magazine holder ( 7 ) and the clamping magazine ( 6 ), in or on the magazine holder ( 7 ) or the clamping magazine ( 6 ) is arranged. Device according to one of the preceding claims, characterized by at least one mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) between the handling device ( 1 ) and the gripper ( 2 ), in or at the handling device ( 1 ) or the gripper ( 2 ) is arranged to allow a compensation movement between the workpiece ( 3 ) and the handling device ( 1 ) at least in a plane perpendicular to the second direction. Device according to one of the preceding claims, characterized by a force-moment sensor ( 24 ) for detecting the reaching of the clamping position and controlling the movement of the handling device ( 1 ) to a first position and / or in the second direction in the clamping position, wherein the force-moment sensor ( 24 ) in or on the gripper ( 2 ) or the handling device ( 1 ) is arranged. Device according to one of claims 3 or 4, characterized by a force-moment sensor ( 24 ) for detecting the reaching of the clamping position and controlling the movement of the handling device ( 1 ) to a first position and / or in the second direction in the clamping position, wherein the force-moment sensor ( 24 ) in or on the magazine ( 6 ) or the magazine holder ( 7 ) is arranged. Device according to one of the preceding claims, characterized in that the clamping magazine ( 6 ) has a rectangular frame with transverse webs ( 8th ) and thereon arranged holding pins ( 5 ), in each case at least two retaining pins ( 5 ) a clamping station or clamping position for a workpiece ( 3 ) form. Device according to one of claims 5 to 7, characterized in that the first position is predetermined and stored. Device according to one of claims 3 to 8, characterized in that the mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) a planar joint ( 9 ). Device according to the preceding claim, characterized in that the planar joint ( 9 ) permits translational movements in the plane perpendicular to the second direction and / or rotations about the second direction as an axis. Device according to one of claims 3 to 10, characterized by at least one further mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) for enabling a compensatory rotational movement between the workpiece ( 3 ) and the handling device ( 1 ) and / or the magazine ( 6 ) and the magazine holder ( 7 ) about the second direction as an axis, which is between the handling device ( 1 ) and the gripper ( 2 ), in the handling device ( 1 ) or the gripper ( 2 ), between the magazine holder ( 7 ) and the clamping magazine ( 6 ), in the magazine holder ( 7 ) or in the clamping magazine ( 6 ) is arranged. Device according to one of claims 3 to 10, characterized by at least one further mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) to allow a compensation movement between the workpiece ( 3 ) and the handling device ( 1 ) and / or between the magazine ( 6 ) and the magazine holder ( 7 ) in the second direction, between the handling device ( 1 ) and the gripper ( 2 ), in the handling device ( 1 ) or the gripper ( 2 ), between the magazine holder ( 7 ) and the clamping magazine ( 6 ), in the magazine holder ( 7 ) or in the clamping magazine ( 6 ) is arranged. Device according to one of claims 11 or 12, characterized in that the further mechanical compliance ( 13 - 15 . 21 . 26 - 28 ) in the second direction as anti-jamming, as collision protection ( 12 ) and / or designed as monitoring of the workpiece position. Device according to one of the preceding claims, characterized by a device for generating a secondary movement of the workpiece ( 3 ), the gripper ( 2 ) and / or the magazine ( 6 ). Device according to the preceding claim, characterized in that the device for generating a secondary movement in or on the gripper ( 2 ), the handling device ( 1 ), the clamping magazine ( 6 ) and / or the magazine holder ( 7 ), between the handling device ( 1 ) and the gripper ( 2 ) or between the clamping magazine ( 6 ) and the magazine holder ( 7 ) is arranged. Device according to one of the two preceding claims, characterized in that as a secondary movement, a vibration and / or rotation can be generated. Device according to one of the three preceding claims, characterized in that the device for generating a secondary movement comprises a vibrator ( 11 ). Device according to one of the preceding claims, characterized in that the gripper ( 2 ) is designed such that during the movement of the handling device ( 1 ) in the second direction the clamping pins forming a terminal location ( 5 ) are spread apart. Device according to one of the preceding claims, characterized in that on the handling device ( 1 ) and / or the gripper ( 2 ) a device for spreading apart of a clamping place forming a clamping pin ( 5 ) is arranged. Device according to the preceding claim, characterized in that the device for spreading apart a wedge ( 23 ), an angle or a second gripper ( 22 ) with suitable grip fingers. Method for the automatic assembly of possibly by means of a magazine holder ( 7 ) held clamp magazines ( 6 ) with workpieces ( 3 ) using a device according to one of the preceding claims, wherein the workpiece ( 3 ) with a gripper ( 2 ) is recorded and held, wherein with an optical sensor ( 17 ) detects the clamping position and a movement of the handling device ( 1 ) is controlled on the basis of the sensor signals, the gripper ( 2 ) in a first direction and then in a second direction in the clamping position of the workpiece ( 3 ), and then the workpiece ( 3 ) of the gripper ( 2 ) is released in the clamping position. Method according to the preceding claim, characterized in that a compensation movement between the workpiece ( 3 ) and the handling device ( 1 ) and / or between the clamping magazine ( 6 ) and the magazine holder ( 7 ) is performed in a plane perpendicular to the second direction. Method according to one of the two preceding claims, characterized in that by means of a force-moment sensor ( 24 ) detects the reaching of the clamping position in the plane perpendicular to the second direction and the movement of the handling device ( 1 ) is controlled to a first position and / or in the second direction in the clamping position. Method according to the preceding claim, characterized in that with a sensor ( 17 ) detects the clamping position and the movement of the handling device ( 1 ) is controlled in a first direction to reach the first position. Method according to one of the two preceding claims, characterized in that the first position is predetermined and stored. Use of a device and / or a method according to one of the preceding claims for the automatic loading of tolerance-affected clamping magazines ( 6 ) with workpieces ( 3 ), for the placement of coating racks for the electrochemical coating or for loading galvanizing racks. Use according to the preceding claim for the automatic loading of tolerance-loaded clamping magazines ( 6 ) with workpieces ( 3 ) of a size between 1 mm and 1000 mm, 1 mm and 100 mm or 1 mm and 10 mm.

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