Apparatus and Method for Gripping an Object

Abstract

An apparatus for gripping an object includes a base element and at least three gripping arms which are mounted on the base element. The at least three gripping arms are each movable independently of one another relative to the base element and the object can be picked up by the at least three gripping arms. The at least three gripping arms each have a hook-shaped gripping tool.

Claims

1.-15. (canceled)

16. An apparatus for gripping an object, comprising: a base element; and at least three gripping arms which are mounted on the base element, wherein the at least three gripping arms are each movable independently of one another relative to the base element and wherein the object can be picked up by the at least three gripping arms; wherein the at least three gripping arms each have a hook-shaped gripping tool.

17. The apparatus according to claim 16, wherein the hook-shaped gripping tool is mounted via a connection end on an adjustment device of the respective gripping arm so as to be rotatable about a tool rotation axis.

18. The apparatus according to claim 16, wherein the hook-shaped gripping tool has at least one cutting edge which is hookable into the object in order to pick up the object.

19. The apparatus according to claim 18, wherein the at least one cutting edge is disposed in a hollow of the hook-shaped gripping tool.

20. The apparatus according to claim 18, wherein the hook-shaped gripping tool is orientable with the at least one cutting edge at an angle of 25 degrees to 95 degrees relative to a plane spanned by a surface of the object and wherein the hook-shaped gripping tool is applied to the surface in order to pick up the object.

21. The apparatus according to claim 16, wherein the at least three gripping arms are pivotable relative to the base element about respective associated rotation axes.

22. The apparatus according to claim 21, wherein the respective associated rotation axes are disposed parallel to one another.

23. The apparatus according to claim 17, wherein at least one of the at least three gripping arms has a translatory adjustment device as the adjustment device and has a gripping element which is mounted on the translatory adjustment device and which is movable relative to the translatory adjustment device and wherein via the gripping element the hook-shaped gripping tool is held.

24. The apparatus according to claim 23, wherein the gripping element is movable in a direction of a longitudinal extent of the translatory adjustment device.

25. The apparatus according to claim 23, wherein the gripping element is adjustable in terms of a distance of the gripping element relative to the translatory adjustment device.

26. The apparatus according to claim 23, wherein the gripping element has a quick-change device and wherein via the quick-change device the hook-shaped gripping tool is held via a quick-release fastener.

27. The apparatus according to claim 16, further comprising: a detection device, wherein the object is detectably by the detection device; an electronic computing device, wherein a sensor signal characterizing the object is receivable by the electronic computing device from detection device and wherein a relative position of the object relative to the at least three gripping arms is determinable by the electronic computing device in dependence on a received sensor signal; and a control device, wherein, in dependence on a determined relative position of the object by the electronic computing device, the at least three gripping arms are movable relative to the object and the respective hook-shaped gripping tools are applyable to the object by the control device.

28. The apparatus according to claim 16, further comprising a fastening device, wherein the apparatus is fastenable to a robot by the fastening device.

29. A method for gripping an object by the apparatus according to claim 16, comprising the steps of: moving the at least three gripping arms independently of one another relative to the base element; and applying the respective hook-shaped gripping tools of the at least three gripping arms to a surface of the object.

30. The method according to claim 29, wherein the hook-shaped gripping tool has at least one cutting edge which is hooked into the object, wherein the hook-shaped gripping tool is oriented with the at least one cutting edge at an angle of 25 degrees to 95 degrees relative to a plane spanned by a surface of the object, and wherein the hook-shaped gripping tool is applied to the surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a perspective view of a robot having an apparatus for gripping a motor vehicle component, by means of which the motor vehicle component is picked up and which can be adapted to the motor vehicle component;

[0024] FIG. 2 is a perspective view of the apparatus for gripping the motor vehicle component having three gripping arms which are flexibly movable relative to one another and by means of which a gripping tool can be held via a respective quick-release fastener of a quick-change device, by means of which gripping tool the motor vehicle component can be gripped particularly securely;

[0025] FIG. 3 is a perspective view of the apparatus having one hook-shaped gripping tool held on each gripping arm, wherein the gripping tools have a cutting edge via which the gripping tools can be applied to the motor vehicle component;

[0026] FIG. 4 is a perspective view of two apparatuses by means of each of which a motor vehicle component is picked up and by means of which the motor vehicle components can be oriented relative to one another; and

[0027] FIG. 5 is a perspective view of the apparatuses according to FIG. 4 by means of which the motor vehicle components are placed together, wherein the apparatuses free a particularly large process space via which the motor vehicle components can be processed.

DETAILED DESCRIPTION OF THE DRAWINGS

[0028] Identical elements are provided with identical reference numerals in the figures.

[0029] FIG. 1 shows a robot 1 by means of which an apparatus 2 for gripping an object is held. In the following text, the apparatus 2 will be described in connection with the picking up of a motor vehicle component 3 as the object. By means of the robot 1, the apparatus 2 is movable relative to the motor vehicle component 3 in order to allow the apparatus 2 to be applied to the motor vehicle component 3. The robot 1 can be used, for example, in a production system for motor vehicles, in particular motor cars, wherein the motor vehicle component 3 is gripped by means of the apparatus 2, the apparatus 2 is moved by means of the robot 1, and then the motor vehicle component 3 is released by the apparatus 2, whereby the motor vehicle component 3 can be transported from a first location to a second location.

[0030] The apparatus 2 is shown in greater detail in FIG. 2. It can be seen therein that the apparatus 2 comprises a base element 4 and three gripping arms 5 mounted on the base element 4. The gripping arms 5 are mounted on the base element 4 so as to be movable relative to the base element 4. In the present case, the gripping arms 5 are pivotable independently of one another relative to the base element 4 in a common movement plane about respective rotation axes 6 which are oriented parallel to one another. The apparatus 2 comprises rotation devices 15 which are associated with the gripping arms 5 and via which the gripping arms 5 are pivotable relative to the base element 4 about the rotation axes 6. In the present case, the rotation devices 15 are rotary tables. The three gripping arms 5 can thereby be set at an optimal angle relative to one another. In the present case, each of the gripping arms 5 has its own associated rotation axis 6. In an alternative embodiment (not shown), the rotation axes 6 can coincide.

[0031] In the present case, each of the gripping arms 5 comprises a translatory adjustment device, which in the present case is a rail 7, and a gripping element 8 mounted on the rail 7. In the present case, the rails 7 extend perpendicular to the rotation axes 6. The rails 7 provide traversing axes for the gripping elements 8. This means that the gripping elements 8 are movable relative to the rails 7 in a direction of longitudinal extent of the rails 7. In the present case, two of the three gripping arms 5 comprise a vertical adjustment device 9 by means of which a distance between the gripping elements 8 and the associated rails 7 of the gripping arms 5 is adjustable. In the present case, an adjustment direction of the vertical adjustment device 9 extends parallel to the associated rotation axes 6 of the gripping arms 5. Via the vertical adjustment devices 9, the gripping elements 8 can be moved closer to the rail 7 or away from the associated rail 7.

[0032] In order to be able to adapt the apparatus 2 particularly advantageously to the motor vehicle component 3 to be picked up, the gripping elements 8 each comprise a quick-change device 10. The quick-change device 10 is adapted to hold a gripping tool 16, which is adapted to the motor vehicle component 3 to be picked up, via a quick-release fastening. By holding the gripping tool 16 that is adapted to the motor vehicle component 3 to be gripped, the apparatus 2 can be adapted particularly quickly and easily to the motor vehicle component 3 by choosing the gripping tools 16 associated with the motor vehicle component 3. The gripping tools 16 will be explained in greater detail hereinbelow in connection with FIG. 3.

[0033] In order that the apparatus 2 can be held by means of the robot 1, the apparatus 2 comprises a fastening device 11, which in the present case is indicated diagrammatically by a box. Via the fastening device 11, the apparatus 2 can be fastened to the robot 1 and mounted on the robot 1. The fastening device 11 thus allows the apparatus 2 to be fastened particularly securely and easily to the robot 1, so that, by means of the robot 1, the apparatus 2 is movable relative to the motor vehicle component 3 to be gripped. For automated tool change at the robot 1, the fastening device 11 can be in the form of an automatic docking system.

[0034] In order to allow the motor vehicle component 3 to be gripped particularly precisely by means of the apparatus 2, the apparatus 2 in the present case comprises a detection device 12. In the present case, this detection device 12 comprises a camera device. The detection device 12 allows the apparatus 2 to be positioned relative to the motor vehicle component 3 by means of camera object detection. An image of the motor vehicle component 3 can be recorded by means of the camera device. The detection device 12 provides a sensor signal characterizing the image to an electronic computing device 13 of the apparatus 2. The received sensor signal can be evaluated by means of the electronic computing device 13. As a result of the evaluation of the sensor signal, a relative position of the apparatus 2, in particular of the gripping arms 5, relative to the motor vehicle component 3 can be determined. The electronic computing device 13 provides the determined relative position to an electronic control device 14 of the apparatus 2. By means of the control device 14, which like the electronic computing device 13 is indicated diagrammatically by a box, the gripping arms 5 are movable relative to the base element 4 in order to apply the gripping tools 16 to the motor vehicle component 3. As a result of receiving the relative position of the apparatus 2, or of the gripping arms 5, relative to the motor vehicle component 3 to be gripped, the gripping arms 5 are moved relative to the motor vehicle component 3 by means of the electronic control device 14 in dependence on the determined relative position in order to be able to pick up the motor vehicle component 3 particularly precisely. During a movement of the gripping arms 5 relative to the base element 4, or relative to the motor vehicle component 3, the motor vehicle component 3 can thereby repeatedly be recorded at regular intervals by means of the detection device 12. This makes it possible for the electronic computing device 13 to determine a relative position of the apparatus 2, or of the gripping arms 5, relative to the motor vehicle component 3 that is associated with the recordings of the motor vehicle component 3. In dependence on the plurality of determined relative positions, which have been determined at time intervals relative to one another, the movement of the gripping arms 5 relative to the motor vehicle component 3 can be adapted and thus corrected by means of the electronic control device 14. The motor vehicle component 3 can thereby be picked up particularly precisely by means of the apparatus 2. Alternatively or additionally, the relative position of the apparatus 2, or of the gripping arms 5, relative to the motor vehicle component 3 determined by means of the electronic computing device 13 can be provided to a further electronic control device, wherein the robot 1 is controllable by means of the further electronic control device in order to orient the apparatus 2 relative to the motor vehicle component 3 in dependence on the determined relative position.

[0035] FIG. 3 shows the apparatus 2, wherein a gripping tool 16 is held via each of the gripping elements 8. In the present case, the gripping tools 16 are hook-shaped and thus form cutting hooks. The cutting hooks each have a free end and an end that is connected to the respective gripping elements 8. Via the respective end, the gripping tools 16 are rotatable relative to the gripping elements 8 about tool rotation axes 17. Each gripping tool 16 has an associated tool rotation axis 17. The tool rotation axes 17 of all the gripping tools 16 are oriented parallel to one another. In the present case, the tool rotation axes 17 extend parallel to the rotation axes 6 of the gripping arms 5. In the present case, the tool rotation axes 17 extend through a center axis of the ends of the gripping tools 16 that are connected to the gripping elements 8. The rotatability of the gripping tools 16 about the associated rotation axes 17 allows the gripping tools 16 to be oriented in dependence on an outer contour of a surface, associated with the gripping tools 16, of the motor vehicle component 3. The gripping tools 16 are to be applied to the associated surface of the motor vehicle component 3 in order to pick up the motor vehicle component 3.

[0036] As can be seen in an enlarged view of the gripping tool 16 in FIG. 3, each gripping tool 16 has a hollow 20, which is provided by a curve of the gripping tool 16. Within the hollow 20, the gripping tools 16 have a cutting edge 18 which can be brought into contact with the surface of the motor vehicle component 3 in order to pick up the motor vehicle component 3. This means that the cutting edge 18 is applied to the surface of the motor vehicle component 3 in order to pick up the motor vehicle component 3 by means of the apparatus 2. In order that the motor vehicle component 3 is picked up particularly securely by means of the gripping tools 16, the gripping tools 16 are hooked with the cutting edges 18 on the surface of the motor vehicle component 3. In order to ensure that the cutting edges 18 of the gripping tools 16 are hooked particularly securely onto the associated surface of the motor vehicle component 3, the cutting edges 18 are to be set at an angle of from 30 degrees to 90 degrees relative to a plane spanned by a surface of the gripping tool 16 relative to the surface of the motor vehicle component 3. This means that a first plane spanned by a surface of the gripping tool 16 encloses an angle which has a value of from 30 degrees to 90 degrees with the second plane spanned by the associated surface of the vehicle component 3, wherein the surface of the gripping tool 16 spanning the first plane provides and defines the cutting edge 18.

[0037] FIG. 4 shows a process of joining two motor vehicle parts 3, wherein each of the motor vehicle parts 3 is picked up by means of a separate apparatus 2—as has already been described in connection with FIGS. 1 to 3. One of the motor vehicle components 3 is picked up by means of each apparatus 2. The apparatuses 2 are each movable relative to one another by means of a robot 1, whereby the motor vehicle components 3 picked up by the apparatuses 2 can be oriented relative to one another. In the present case, the motor vehicle components 3 are placed together by means of the apparatuses 2. FIG. 5 shows the motor vehicle parts 3 in their state placed together by means of the apparatuses 2. It can be seen in that figure that a particularly small space around the motor vehicle components 3 is covered by the apparatuses 2 holding the motor vehicle components 3. In the case of the arrangement of the motor vehicle components 3 in which they are placed together, there is thus a particularly large free process and working space 19 in which a tool can be moved in order to process at least one of the motor vehicle components 3, in particular to join the motor vehicle components 3 together.

[0038] The described hook-shaped gripping tools 16 allow the motor vehicle component 3 to be held particularly securely by means of the apparatus 2, whereby, with a particularly small triangle of forces spanned between the gripping tools 16 of the apparatus 2, the motor vehicle component 3 can be held particularly securely, which results in a particularly large process and working space. By means of the gripping tools 16, the motor vehicle component 3 is thus to be held particularly securely via the triangle of forces spanned by the gripping tools 16, whereby the particularly large process and working space at the motor vehicle part 3 can be kept free for processing of the motor vehicle part 3.

[0039] The described apparatus 2 and the described method for gripping the motor vehicle component 3 by means of the apparatus 2 are based on the finding that, owing to a high degree of automation in vehicle body construction, a large number of gripping systems are used for gripping motor vehicle components 3. Many of these gripping systems have only comparatively low flexibility. The apparatus 2 makes it possible for a wide range of motor vehicle components 3, including assemblies, in vehicle construction to be gripped particularly advantageously. A three-dimensional movement of the gripping arms 5 relative to the motor vehicle component 3 to be gripped is thereby possible. This allows the motor vehicle component 3 to be gripped by means of the apparatus 2 independently of its features or in dependence on its features. In many flexible grippers of the prior art, components are picked up by movable, form-fitting engagement.

[0040] The hook-shaped gripping tools 16 allow the motor vehicle component 3 to be picked up by a principle of forming cooperating triangles of forces. A particularly large amount of process space and working space can thereby be obtained. Furthermore, small components and very small components can be picked up by means of the hook-shaped gripping tools 16, in particular from a box.

[0041] At present, objects such as sheet-metal components are fixed, picked up and transported by a double cone or a double sphere via pick-up holes and trimming clamps in a large-area triangle formation or line formation. In order to make this possible in the prior art, pick-up holes or apertures have to be provided in the sheet-metal parts and uniform triangles of forces have to be formed, the orientation of which is as large as possible so as not to drop the object.

[0042] In the described apparatus, in contrast to the prior art, the hook-shaped gripping tools 16, which are cutting hooks, are provided on each of the gripping arms 5, which are each rotatable relative to the gripping elements 8 through 360 degrees about the second rotation axis 17. For picking up the object, the gripping tools 16 with their cutting edges 18 are oriented so that they enclose a cutting angle of from 30 degrees to 90 degrees with a plane spanned by a surface of the object, and clasp or clamp the object. A cut, in particular a micro-cut, is thereby formed in the object. There is no damage to the object.

[0043] When a double cone or a double sphere is used, uniform triangles of forces with as large an orientation as possible have to be chosen, whereby a process and working space is covered by the triangle of forces. When the hook-shaped gripping tools 16 are used, the object can be picked up with the formation of particularly small triangles of forces, whereby a particularly large process and working space 19 is freed at the object by the apparatus.

[0044] Overall, the invention shows how a flexible gripping system, which has gripping arms 5 which are actuatable particularly flexibly, and a scalable component clamp as the gripping tool 16 can be provided in the apparatus in order to gain process space.

LIST OF REFERENCE CHARACTERS

[0045] 1 robot

[0046] 2 apparatus

[0047] 3 motor vehicle component

[0048] 4 base element

[0049] 5 gripping arm

[0050] 6 rotation axis

[0051] 7 rail

[0052] 8 gripping element

[0053] 9 vertical adjustment device

[0054] 10 quick-change device

[0055] 11 fastening device

[0056] 12 detection device

[0057] 13 electronic computing device

[0058] 14 electronic control device

[0059] 15 rotation device

[0060] 16 gripping tool

[0061] 17 tool rotation axis

[0062] 18 cutting edge

[0063] 19 process and working space

[0064] 20 hollow