WO2012163390A1

WO2012163390A1 - A configurable handling tool system

Info

Publication number: WO2012163390A1
Application number: PCT/EP2011/058771
Authority: WO
Inventors: Antonio RODA LEAL; Ramon Casanelles Moix
Original assignee: Abb Technology Ag
Priority date: 2011-05-27
Filing date: 2011-05-27
Publication date: 2012-12-06
Also published as: CN203887859U; EP2714342A1

Abstract

It comprises a handling tool comprising a frame, at least one gripping element mounted on said frame and positionable in a plurality of positions with respect to the frame, and means for maintaining each said gripping element in locked condition in a plurality of positions; means for releasing at least one gripping element of the handling tool, such that said gripping element adopts a released condition in which it can be repositioned with respect to the frame; and a repositioning unit, separate from said handling tool, adapted to interact with the handling tool when at least one gripping element is in released condition, for repositioning the gripping element with respect to the frame.

Description

A configurable handling tool system

The present invention relates to a configurable handling tool system, which can be employed for example in press lines where robots, such as six-axis robots, transfer a blank or workpiece from one press to another.

It also relates to a configurable handling tool for said system, a robot fitted with the tool, and a method for configuring a handling tool. BACKGROUND ART

Handling tools fitted with a number of suction cups, gripping jaws or other gripping elements, are commonly employed in the manufacturing industry. For example, in a press line for manufacturing vehicle body parts, the robots that transfer the metal sheet workpieces from one station to another are fitted with such handling tools, to pick up the workpieces from one station or press and place them in the next.

The location and orientation of vacuum cups or other gripping elements on the tool frame must be adapted to the size and shape of the blanks or workpieces to be handled, which changes from one station to another: consequently, a large number of different handling tools is needed, for example five different tools for each part to be manufactured in a line for vehicle body parts; since the same line is employed for several different body parts, the number of handling tools that need to be provided, classified, stored, etc. can be quite large.

When one batch of a certain vehicle body part has been manufactured and the press line is changed to start a batch of a different vehicle body part, the handling tools of the robots in the line must all be withdrawn and stored away, and new handling tools must be fetched and mounted on the robots.

Solutions have been devised for at least partly automating the change of the handling tools for each robot, but they fail to avoid the need to provide and store a large number of different handling tools, with its associated drawbacks. This problem has been addressed by providing a configurable handling tool which comprises servomotors provided on the tool frame, in association with the vacuum cups or gripping elements, in order to change their position with respect to the frame. This solution, although acceptable for some manufacturing lines, has the drawback that the presence of the motors causes the handling tool to be bulky and heavy, thus requiring heavier and more powerful robots; furthermore these configurable tools are unsuitable in some applications, for example when the handling tool is employed in a press line, because the volume of the tool makes it impossible for it to enter the press.

The present invention aims to provide a handling tool system which solves at least partly the above drawbacks. SUMMARY OF THE INVENTION

In a first aspect, the invention provides a configurable handling tool system comprising: a handling tool comprising a frame, at least one gripping element mounted on said frame and positionable in a plurality of positions with respect to the frame, and means for maintaining each said gripping element in locked condition in each of said plurality of positions; means for releasing at least one gripping element of the handling tool, such that said gripping element adopts a released condition in which it can be repositioned with respect to the frame; and a repositioning unit, separate from said handling tool, adapted to interact with the handling tool when at least one gripping element is in released condition, for repositioning the gripping element with respect to the frame.

The provision of gripping elements positionable in a plurality of positions on the frame, and of a separate repositioning unit which interacts with the handling tool to reposition the gripping elements, allows reducing the number of different handling tools needed in order to handle several different parts or blanks, without a substantial increase of the bulk and weight of the tool.

In further aspects, the invention provides a configurable handling tool for a system according to the invention, a robot fitted with such a configurable handling tool, and also a method for configuring a handling tool, as claimed in claim 16.

Additional objects, advantages and features of embodiments of the invention will become apparent to those skilled in the art upon examination of the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Particular embodiments of the present invention will be described in the following by way of non-limiting examples, with reference to the appended drawings, in which:

Figure 1 is a perspective view showing a handling tool system according to a first embodiment of the invention, with the handling tool fitted to a robot, and with a repositioning unit in the form of an auxiliary robot;

Figure 2 is a partial perspective view of a handling tool fitted with a positionable vacuum cup; Figures 3a and 3b show a handling tool system according to a further embodiment of the invention, in two different positions;

Figure 4 is a partial section taken along line IV-IV of figure 3b; Figure 5 is a plan view of the repositioning unit of the system of figures 3a,

3b; and

Figure 6 is an enlarged detail of figure 4.

DETAILED DESCRIPTION OF EMBODIMENTS

Figure 1 shows a configurable handling tool system according to a first embodiment of the invention.

The system may comprise a configurable handling tool 10 with gripping elements 12, a device (not shown in figure 1 ) to release the gripping elements 12 so that they may be repositioned, and a repositioning unit 100 separate from the handling tool 10.

By way of example, in figure 1 the handling tool 10 is shown fitted to a six- axes robot R of the kind employed for example to transfer parts or workpieces from one press to another in a manufacturing press line; however, embodiments of the handling tool system of the present invention may be employed in other kinds of robots or manipulators.

The handling tool 10 of the system may comprise a frame 1 1 and a plurality of gripping elements 12, which may be vacuum cups as in figure 1 , but also jaws, magnetic grippers or any other kind, depending on the part to be handled by the tool.

The gripping elements 12 may be mounted on the frame 1 1 in such a way as to be placed in different positions with respect to the frame, and may be maintained in locked condition in a plurality of positions.

The separate repositioning unit 100 may be a robot fitted with a jaw 101 or other device capable of engaging a gripping element 12 of the handling tool and carry out its repositioning with respect to the frame 1 1 ; but it may also be a passive, stationary unit, which interacts with the handling tool to allow the gripping elements of the handling tool to be repositioned by the action of the robot, as will be explained later on. By a separate repositioning unit it is meant a unit that is not mounted on the frame of the handling tool, and is independent from the tool. It may be a stand alone unit, or in certain cases it may be associated to the robot to which the handling tool is fitted. The operation of a configurable handling tool system according to an embodiment of the invention will now be described schematically with reference to figure 1 . When a change in a handling tool is needed, for example because in a press line a batch of a car body part has been finished, and manufacture of a different car body part has to be started, the robot R to which the configurable handling tool 10 is fitted may transfer the handling tool 10 to a position in correspondence with the separate repositioning unit 100 (situation of figure 1 ), and the jaw 101 of this unit may engage a gripping element 12 of the handling tool 10. The gripping element 12 engaged by the jaw 101 may then be released from its locked condition by a releasing device, which will be described later on, and may thus adopt a released condition, in which it can be repositioned with respect to the tool frame 1 1 . The repositioning unit 100 of the system may then manoeuvre to place it in a new position (location and/or orientation) with respect to the frame 1 1 ; the gripping element 12 can then be locked again with respect to the frame 1 1 in the new position.

The robot R and/or the repositioning unit 100 may then move such that the jaw 101 engages another gripping element 12, and the process may be repeated until all the gripping elements 12 that need to be changed have been repositioned.

The result of the process is that the same handling tool 10 fitted to the robot R and previously employed for one car body part workpiece is now suitably configured for handling another, different car body part workpiece.

Figure 2 shows a detail of the mounting of one vacuum cup 12 on the frame 1 1 according to one embodiment of the invention. On one member of the frame 1 1 may be mounted a first sliding block 13 arranged on a suitable bearing 14 or other sliding system, and the block may carry a first arm 15, such that the arm 15 may slide along the frame member 1 1 in the Y direction. A first pneumatic cylinder 16 allows locking the block 13, and thus the arm 15, on the frame member 1 1 , in any position.

A second sliding block 17 may be mounted on the first arm 15 with a bearing 18, and said second sliding block 17 may carry a second arm 19. The second arm 19 may thus slide together with block 17 along the first arm 15, in an X direction, and may also rotate around the first arm 15. A second pneumatic cylinder 20 may lock the sliding block 17, and thus the second arm 19, on the first arm 15, in any position.

The second arm 19 may have a pin 21 attached at its end, and a bushing 22 attached at the end of a third arm 23 may be arranged to receive the pin 21 . This arrangement allows the third arm 23 to rotate with respect to the second arm 19. A third pneumatic cylinder 24 allows locking the third arm 23 in any position with respect to the second arm 19, by tightening the bushing 21 around the pin 21 .

It will be appreciated that by the combined rotations of the second arm 19 around the first arm 15, and of the third arm 23 around the second arm 19, the end of the third arm 23 opposite the pin 22 may be displaced vertically, in a Z direction; furthermore, this possibility of vertical displacement is achieved without adding to the vertical dimension of the handling tool beyond that occupied by the two arms in each position. Limiting the vertical dimension of the tool is an advantage when the tool is employed to load or unload presses, where the vertical space available is small.

At the end of the third arm 23 which is remote from the pin 22 may be mounted a ball joint 25, which allows positioning a vacuum cup 12 with three degrees of freedom (rotations α, β, γ, as shown in the figure) with respect to the third arm 23. A fourth pneumatic cylinder may lock the ball joint 25, such that the vacuum cup 12 may be locked in any position.

In this embodiment, the four pneumatic cylinders 16, 20, 24 and 26 may have the function of maintaining their respective joints in locked condition in a plurality of positions, and may have also the function of releasing the joints such that the arms 15, 19, 23 and the vacuum cup 12 adopt a released condition in which they can be repositioned.

It will be understood that by means of this arrangement, the vacuum cup or other gripping element 12 may be arranged with respect to the frame 1 1 (and with respect to other parts of the mounting) in a plurality of positions, including degrees of freedom of linear movement as well as rotation. In the present specification, the term positioning is meant to encompass placing the gripping element 12 at a certain location on the frame 1 1 or with respect to the frame 1 1 (translations X, Y, Z), and/or orientating the gripping element 12 (rotations α, β, γ).

Many different embodiments of the configurable handling tool described with reference to figures 1 and 2 are possible, some of which will be described in the following. The handling tool 10 may comprise gripping sections, each comprising several gripping elements 12 that may all be repositioned together, at least with some degree of freedom: for example, the first arm 15 in figure 2 may be such a gripping section and may carry several gripping elements 12 along its length, each with a mounting system as shown for the vacuum cup in the figure. All the elements may be displaced together along direction Y by releasing and displacing the first arm or gripping section 15 with respect to frame member 1 1 , and then each gripping element 12 can be separately released and repositioned with respect to the gripping section 15. The mounting of the gripping elements 12 on a gripping section such as the first arm 15 may also be carried out in a different manner for each element and/or with different degrees of freedom.

In operation, a gripping element 12 may be repositioned by acting sequentially and separately on each degree of freedom; for the embodiment of figure 2, for example, it is possible to first releasing and repositioning the first arm 15 with respect to the frame 1 1 and locking the arm 15 in the new position, then releasing the arms 19 and 23, repositioning them with respect to the first arm 15, and locking them in their new position, and finally releasing the ball joint 25 to reposition the gripping element 12 as to its orientation, and locking it again in the new orientation.

Alternatively the operation may be carried out by engaging the gripping element 12 in the repositioning unit 100, releasing all the degrees of freedom of the gripping element 12 with respect to the frame member 1 1 , and repositioning the gripping element 12, in one single manoeuvre. It is also possible to act jointly on some of the degrees of freedom and separately on others.

The means for releasing the gripping elements 12 such that they adopt a released condition with respect to the frame 1 1 may be mounted on the handling tool itself, as for example the pneumatic cylinders in the embodiment of figure 2, but may also be separate from the handling tool 10; for example, they may be incorporated or fitted on the repositioning unit 100. The tool frame 1 1 may be a single tubular member, for example as in figure 1 , on which one or more gripping sections may be mounted, or it can be embodied as a structure including several frame members fixed to each other, with gripping sections and/or gripping elements mounted thereon. Figures 3a and 3b show another embodiment of a configurable handling tool system according to the present invention, in two steps of the operation in which the tool configuration is changed.

In the embodiment of figures 3a, 3b a configurable handling tool 50 comprises a frame 51 , in this case a square-section tubular bar, with an attachment 52 for being fitted to a robot (not shown), and four gripping sections 53, 54, 55 and 56, which may each be an arm on which several gripping elements 12, such as vacuum cups, may be mounted. The gripping elements 12 may be fixed on each gripping section 53 to 56.

Each gripping section 53 to 56 is mounted in such a way that it can slide along the frame 51 , and may be maintained in locked condition in any position along the frame 51 and released such as to adopt a released condition in which it can be moved along the frame to be repositioned.

The embodiment of the system shown in figures 3a, 3b may also comprise a separate repositioning unit 200, which in this case may be a passive unit comprising a post 201 fixed to the floor 300. The operation of a configurable handling tool system according to this embodiment of the invention will now be described schematically. When a change in the handling tool 50 is needed, the robot (not shown) to which the tool 50 is fitted may transfer the tool 50 towards the position of figure 3a, in correspondence with the separate repositioning unit 200. The tool 50 may be placed by the robot (not shown) in such a way that the gripping section 53 to be repositioned is engaged with the repositioning unit 200 and released from its locking condition on the frame 51 to a released condition, in which it is free to slide along the frame 51 , in a manner that will be described further on.

The handling tool 50 may be then displaced by the robot (not shown) in the direction of the arrow A (figure 3b): as a consequence of the engagement of the gripping section 53 with the stationary repositioning unit 200, this section 53 remains stationary during the displacement of the rest of the handling tool 50, such that the gripping section slides along the frame 51 to the position shown of figure 3b, in which the gripping section 53 can be seen much closer to the gripping section 54 than in figure 3a.

The gripping section 53 is then disengaged from the repositioning unit 200 and locked again to the frame 51 , by a further movement of the robot (not shown). It will be understood that a similar process may be carried out to reposition the rest of the gripping sections 54 to 56, if needed.

The result of the process is that the handling tool 50 is reconfigured so as to be suitable for handling a different part or blank.

A more detailed description of this embodiment of the handling tool system will be described in the following with reference to figures 4 to 6. Figure 4 is a partial section taken along line IV-IV of figure 3b, and shows the mounting of the gripping section 53 on the frame 51 .

The end of the gripping section 53 may be attached to a plate 60, which may be slidably mounted on a pair of guides 61 provided on the underside of the frame 51 .

The plate 60, and thus also the gripping section 53, may be maintained locked to the frame 51 in any position along the frame 51 , and released by engagement with the repositioning unit 200, as better seen in the enlarged detail of figure 6. In figure 6, attached to the plate 60 of the gripping section 53 there is shown a locking device 70, which may comprise a housing 71 in which is slidably received a bolt 72. The bolt 72 has a tip 73 which may be engaged into a complementary recess 74 provided on the frame 51 of the handling tool 50. A spring 75 may be arranged around the bolt 72, between the housing 71 and an abutment 76 attached to the bolt, such that the bolt 72 may be urged towards the recess 74. The locking device thus may maintain the plate 60, and thus the gripping section 53, in a locked condition with respect to the tool frame 51 .

The bolt 72 projects from the housing 71 at its end opposite the tip 73, and a bushing 77 is arranged around the bolt 72 outside the housing 71 .

The bushing 77 may be engaged by a fork 203 that may be attached at the top of the post 201 of the repositioning unit 200; this fork 203 is better seen in figures 4 and figure 5, the latter being a plan view of the repositioning unit 200.

Turning back to figure 4, it can be appreciated that the plate 60 and the gripping section 53 attached to it may be released from their locking condition by engaging the fork 203 of the repositioning device 200 around the bushing 77 of the locking unit 70, and then moving the tool 50 with the frame 51 upwards: the fork 203 will then maintain the bolt 72 stationary while the frame 51 , plate 60 and housing 71 move upwards, and as a consequence the tip 73 of the bolt 72 will come out of the engagement with the recess 74.

In this released condition, the plate 60 and therefore the gripping section 53 may slide along the frame 51 . At the same time, the engagement with the fork 203 prevents the movement of the plate 60 and the gripping device 53, such that a movement of the handling tool 50 as shown by arrow A in figure 3b (actuated by the robot to which the handling tool is fitted) will cause that the gripping section 53 is displaced with respect to the frame 51 .

Once the desired position for the gripping section 53 is reached, the handling tool 50 is moved downwards again, such that the bolt 72 is again biased by the spring into the recess 74 and the locking device 70 again locks the plate 60 and gripping section 53 with respect to the frame 51 .

The handling tool may then be moved out of engagement with the fork 203.

It will be appreciated that in this embodiment the repositioning unit 200 is passive, i.e. does not perform any active movement or operation and merely interacts with the handling tool 50 which is moved by the robot, in order to release the gripping section 53 from the frame 51 and keep it stationary while the robot moves the rest of the handling tool 50.

In this embodiment, the means for releasing the gripping sections 53 to 56 from the frame 51 are partly incorporated on the handling tool 50 and partly incorporated on the repositioning unit 200, and it is also upon interaction between both parts that releasing is effected.

It will be understood from the above description that embodiments of the present invention also relate to a method for configuring a handling tool, which may comprise providing a handling tool with a frame, gripping elements mounted on said frame and positionable in a plurality of positions with respect to the frame; moving said handling tool to a separate repositioning unit;

bringing the gripping elements to a released condition in which they can be repositioned; repositioning the gripping elements by interaction between the handling tool and the repositioning unit; and locking again the gripping elements on the frame.

The operations for repositioning the gripping elements or gripping sections of the handling tools 10, 50 have been described as being carried out with the tools attached to the robot which performs the press loading / unloading operations or similar work, and this repositioning and reconfiguration process can be done in the downtime available for performing other changes in the press line. However, the repositioning and reconfiguration process may also be carried out separately or independently from the press line work cycle; and this may be especially useful in complex cases where the time needed for repositioning the gripping elements may take longer. In this case, the robot may change in any known way one handling tool for another, previously configured to be suitable for the next press cycle, and the tool the robot has left behind may be then reconfigured for another press cycle. Although only a number of particular embodiments and examples of the invention have been disclosed herein, it will be understood by those skilled in the art that other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof are possible. Furthermore, the present invention covers all possible combinations of the particular embodiments described. The scope of the present invention should not be limited by particular embodiments, but should be determined only by a fair reading of the claims that follow.

Claims

1 . A configurable handling tool system comprising: a handling tool comprising a frame, at least one gripping element mounted on said frame and positionable in a plurality of positions with respect to the frame, and means for maintaining each said gripping element in locked condition in a plurality of positions; means for releasing at least one gripping element of the handling tool, such that said gripping element adopts a released condition in which it can be repositioned with respect to the frame; and a repositioning unit, separate from said handling tool, adapted to interact with the handling tool when at least one gripping element is in released condition, for repositioning the gripping element with respect to the frame.

2. A system as claimed in claim 1 , wherein said releasing means are at least partly incorporated on the handling tool.

3. A system as claimed in any of claims 1 or 2, wherein said releasing means are at least partly incorporated on the repositioning unit.

4. A system as claimed in any of the preceding claims, wherein at least two gripping elements are mounted on a gripping section which is in turn mounted on the frame.

5. A system as claimed in claim 4, wherein the gripping section is positionable in a plurality of positions with respect to the frame, and wherein the means for maintaining each gripping element in locked condition, the means for releasing at least one gripping element, and the repositioning unit are adapted to act on said gripping section.

6. A system as claimed in claim 5, wherein at least one gripping element mounted on the gripping section is positionable with respect to said gripping section, and wherein the means for maintaining each gripping element in locked condition, the means for releasing at least one gripping element, and the repositioning unit are adapted to act on said gripping element that is positionably mounted on the gripping section.

7. A system as claimed in any of the preceding claims, wherein at least one gripping element is mounted on the frame to be positionable with at least two degrees of freedom, and wherein the means for maintaining each gripping element in locked condition, the means for releasing at least one gripping element, and the repositioning unit are adapted to act on at least one degree of freedom separately from at least another degree of freedom of said gripping element.

8. A system as claimed in any of the preceding claims, wherein at least one gripping element is mounted on the frame to be positionable with at least two degrees of freedom, and wherein the means for maintaining each gripping element in locked condition, the means for releasing at least one gripping element, and the repositioning unit are adapted to act jointly on at least two degrees of freedom of said gripping element.

9. A system as claimed in any of the preceding claims, wherein at least one gripping element is a vacuum cup.

10. A system as claimed in any of the preceding claims, wherein the means for maintaining the gripping elements in locked condition comprise at least one pneumatic cylinder.

1 1 . A system as claimed in any of the preceding claims, wherein the means for releasing the gripping elements comprise at least one pneumatic cylinder.

12. A system as claimed in any of claims 1 to 1 1 , wherein the repositioning unit comprises a robot.

13. A system as claimed in any of claims 1 to 1 1 , wherein the repositioning unit comprises a passive unit.

14. A configurable handling tool for a system as claimed in any of the preceding claims.

15. A robot fitted with a configurable handling tool as claimed in claim 14.

16. A method for configuring a handling tool, comprising the steps of providing a handling tool comprising a frame, at least one gripping element mounted on said frame and positionable in a plurality of positions with respect to the frame, moving said handling tool to a separate repositioning unit, bringing at least one gripping element to a released condition in which it can be repositioned, repositioning said at least one gripping element by interaction between the handling tool and the repositioning unit, and locking said at least one gripping element on the frame.