EP0630312A1

EP0630312A1 - Gripper unit for a manipulator robot

Info

Publication number: EP0630312A1
Application number: EP93903708A
Authority: EP
Inventors: Christian Dr. Pieler; Franz Ernst Dr. Leichtfried
Original assignee: Robocon Labor und Industrieroboterges GmbH
Current assignee: Robocon Labor und Industrieroboterges GmbH
Priority date: 1992-02-24
Filing date: 1993-02-23
Publication date: 1994-12-28
Also published as: AT399835B; ATA34692A; WO1993016849A1

Abstract

Dans une unité de préhension pour des robots de manutention, il est prévu au moins deux doigts de préhension (4, 5) disposés sur une pince (1) et pouvant être commandés de manière à se déplacer l'un par rapport à l'autre, doigts qui portent des éléments de maintien (7). Les éléments de maintien (7) présentent des aiguilles de préhension (8) qui peuvent être disposées sur un support commun (9) et dont les extrémités (10) viennent en contact, de manière essentiellement ponctuelle, avec l'élément (2) à saisir, de sorte que celui-ci est maintenu par liaison de forme sous l'action de la force de maintien exercée par la pince (1).In a gripper unit for handling robots, at least two gripper fingers (4, 5) are provided which are arranged on a gripper (1) and can be controlled to move relative to each other , fingers which carry holding elements (7). The holding elements (7) have gripping needles (8) which can be arranged on a common support (9) and whose ends (10) come into contact, in an essentially point-like manner, with the element (2) at grip, so that it is held by form connection under the action of the holding force exerted by the clamp (1).

Description

Gripping unit for handling robots

Technical field

The invention relates to a gripping unit for handling robots, in particular for gripping essentially cuboidal elements made of relatively light material, such as microtiter plates, with at least two gripping fingers which are arranged on a gripper and are controllably movable relative to one another and which have holding elements. State of the art

Such gripping units are known in a wide variety of designs and are mostly relatively closely matched to the respective application in order to optimize their function with regard to the design of the gripping fingers or holding elements. In addition to gripping fingers with holding elements which are precisely matched to the structural conditions of the elements to be handled and which cooperate with them in a form-fitting manner, arrangements have also become known in which the holding elements cooperate frictionally with the surface of the elements to be handled when the gripping fingers are pressed against this surface . On the one hand, this allows a somewhat greater flexibility with regard to the possible uses, but on the other hand has the disadvantage that, in particular due to the properties of the element to be held, only a relatively low permitted gripping or holding force makes it impossible to hold it securely even under unfavorable circumstances.

Especially with the essentially rectangular microtiter plates mentioned at the outset, gripping or holding problems can arise, in particular, if the external design of the plates, which are essentially standardized with respect to the main dimensions, have unforeseen differences, but this also applies to other elements to be gripped similarly applies.

The microtiter plates mentioned are storage and reaction vessels for liquid samples. The width and length (127.7 x 85.4 mm) of the microtiter plates are standardized; however, there are versions of different heights. They can be made from polypropylene, polystyrene, polycarbonate or other plastic materials; can be transparent or opaque be and be used with or without a lid. Some shape details of the microtiter plates can vary between the individual producers, such as the height of the base; some manufacturers oblique two of the four corners of the microtiter plate and the associated lid from _r so that these panels can only be used with covers of the same generator. In other microtiter plate manufacturers, the base is raised in the middle of the plate. Sample wells are inserted into the microtiter plates from above, which are arranged in the most common form in a matrix of 8 x 12 wells, that is a total of 96 wells. However, there are also microtiter plates of the same length and width that contain only 48, 24, 12 or 6 cells, whereby the individual cell diameters are correspondingly larger.

The most common areas of application of microtiter plates are in clinical diagnostics, where they e.g. in the ELISA method (Enzyme-Linked Immuno Assay.) e.g. used in blood banks; in quality control laboratories in the pharmaceutical industry, where they are used to test raw materials and products for the greatest possible purity, e.g. be used in the so-called Li ulus procedure; in pharmaceutical research and development, as well as in biotechnology, where they are used in so-called screening processes in which those with the desired clinical-therapeutic effect can be found from a large number of test substances. Microtiter plates are also used in food and environmental chemistry.

The hitherto known gripping units for microtiter plates are not suitable for error-free gripping of all microtiter plates available on the market, since the holding or gripping force cannot be increased to the extent that the plates are constructed or the handling robots used the holding elements hold the assigned surfaces of the element to be held in a frictionally secure manner. Presentation of the invention

The object of the present invention is to improve a gripping unit of the type mentioned at the outset in such a way that the disadvantages mentioned of the known units of this type are avoided and that, in particular, rectangular elements made of relatively light material, such as microtiter plates, are safe even with different surface structures can be held. According to the present invention, this is achieved in that the holding elements have gripping needles, the ends of which lie essentially point-like on the element to be gripped and hold it positively under the effect of the holding force exerted by the gripper. It has been found that this punctiform holding with naturally at least three gripping needles lying essentially in one plane offers excellent gripping or holding security even with relatively small applied forces. In particular, all known microtiter plates currently available on the market can be gripped in this way, it makes no difference whether the plates have a lid or not. The elements to be gripped can be attacked stably and safely not only in the vicinity of the axes but also near the edges without fear of tipping over. The main advantage lies in the essentially punctiform and therefore positive engagement of the elements to be handled by means of the gripping needles, as a result of which the elements with the gripping or. Holding force of the gripper can be shifted much less easily with respect to the gripper fingers than with the known gripper fingers mentioned at the outset, which act on the elements in a flat and frictional manner.

According to a preferred embodiment of the invention it is provided that a holding element has two gripping needles on a common needle rocker which can be pivoted about an axis arranged on the gripping finger essentially perpendicular to the effect of the holding force and to the direction of an imaginary connecting line between the two gripping needles. On the one hand, unevenness, elevations and depressions on the surface of the element to be gripped can be easily and easily compensated for, and on the other hand it is ensured that the gripping or holding force is distributed as uniformly as possible on the individual gripping needles, so that damage to the element to be gripped is avoided secure gripping and holding are prevented at the same time.

In a further embodiment of the invention, the needle rocker and / or the holder for the gripping needles can be designed to be elastic, which results in a further improvement in safety or the uniform distribution of forces. According to another embodiment of the invention, the needle rocker can also be elastically supported with respect to the gripping finger, which guarantees a secure gripping and holding even, for example, in the event of vibrations during operation.

According to a preferred embodiment of the invention it is provided that a holding element with a needle rocker carrying two gripping needles and on the other hand a holding element with a fixed individual gripping needle is arranged on two interacting gripping fingers. This ensures a secure hold in the simplest way by the gripping needles acting essentially in one plane.

According to a preferred further embodiment of the invention, the gripping needles and / or the gripping fingers carrying the holding elements can be bent and / or cranked. With the smallest space requirement of several elements lying next to one another, to be gripped or held, it can thus be ensured that elements can also be removed and handled in the middle of a row of elements lying next to or behind one another. Brief description of the drawing

The invention is explained in more detail below with reference to the drawings, some of which are shown schematically.

1 shows a gripping unit according to the invention in a perspective view,

2 and 3 each show alternative embodiments of gripping fingers or holding areas to FIG. 1,

4 shows a top view of an exemplary embodiment of a microtiter plate, for example for holding a gripping unit according to the present invention,

5 shows a side view of the microtiter plate in the direction of arrow V in FIG. 4,

5 shows a corresponding side view in the direction of arrow VI in FIG. 4, 7 shows the interaction of a microtiter plate according to FIGS. 4 to 6 with a gripping finger of a gripping unit according to the invention, which has been folded over into the plane of the drawing for clarification,

FIG. 8 shows a view of the gripping finger from FIG. 7 alone in the direction of the arrow 8 in FIG. 7, and

FIG. 9 shows a view essentially corresponding to FIG. 1 of a similar embodiment according to the present invention.

1 shows the outer end of a gripper 1 of a handling robot, not shown, which is used for handling essentially cuboid elements 2 made of relatively light material, such as e.g. Microtiter plates. The gripper 1 can be rotated or swiveled around various axes or adjusted or moved in various directions in a wide variety of ways, which are not of interest here, so that the required handling area can be covered depending on the task. Arranged at the illustrated outer end of the gripper 1 are two gripper fingers 4, 5, which are controllable in the direction of the double arrow 3 and which have 6 holding elements 7 at their outer ends. The holding elements 7, in turn, each have two gripping needles 8 on a common needle rocker 9, the ends 10 of which, under the gripping or holding force that can be exerted via the gripper 1, bear against the element 2 to be gripped essentially at a point and under the latter the form of the holding force. It is relatively irrelevant whether the holding elements 7 engage with the gripping needles 8 in the middle of the element 2 or near its edges, since, due to the secure, form-fitting holding, no tipping can occur.

The principle and mode of operation of the needle rocker 9 are explained in more detail below with reference to FIGS. 7 to 9.

The detail of another exemplary embodiment shown in FIG. 2 differs from FIG. 1 essentially only in that here now on the two cooperating gripping fingers 4, 5, which, as can also be seen in FIG. 1, by means of screws 11 on the not shown here Grippers are interchangeably attached, on the one hand a holding element 7 with a two rocking needles 8 carrying, not shown needle rocker and on the other hand a holding element 7 'with a single fixed gripping needle 8 is arranged. This arrangement is sufficient for many application examples and, according to the principle of three-point mounting, prevents any wobbling in the holder.

In the exemplary embodiment according to FIG. 3, the gripping needles 8 are bent or cranked at the outer ends 6 of the gripping fingers 4, 5, whereby the gap required between two adjacent elements 2 can be reduced to enable gripping. In the arrangement according to FIG. 3, the gripping needles 8 could also be arranged on needle rockers correspondingly modified compared to FIGS. 1 and 2, but this is not shown here.

In all of the illustrated embodiments according to FIGS. 1 to 3, the gripping fingers 4, 5 are themselves bent or cranked and consist of two separately manufactured and assembled parts, as can be seen in particular in FIG. 9. Together with the design of the outer end of the gripper 1 shown in FIG. 1, individual elements 2 can thus be picked out very easily from a series of elements 2 placed next to or behind one another at a distance.

4 to 6 show a so-called microtiter plate as an example of an element 2 to be handled according to FIGS. 1 to 3. Such microtiter plates are used as storage and / or reaction vessels for liquid samples and the like. Various parameters, such as the width and length of such plates, are standardized - other parameters, such as the height and matrix of the sample cup, vary depending on the manufacturer or application. The plates consist entirely of plastic materials such as polypropylene, polystyrene, polycarbonate or the like, both transparent and opaque designs being known. The microtiter plates are produced or used both with and without a separate cover, such a cover, of course, also having to be removable or replaceable by a handling robot when it is being handled. Some shape details of the microtiter plates vary depending on the use or producer, for example the height of the base 12, the susceptible bevel 13 the corners 14, the possible elevation 15 in the middle of the long side edge, etc. The sample cups 16 inserted from above are arranged in the most common form in a matrix of 8 x 12 (as shown), although there are also designs with There are 48, 24, 12 or 6 cells, in which case the individual cell diameters are correspondingly larger.

The most common areas of application for such microtiter plates are clinical diagnostics, quality control in the pharmaceutical industry, pharmaceutical research and development, and biotechnology - but there are also other applications, for example, in food and environmental chemistry.

FIGS. 7 and 8 show an example of the construction of the needle 9 already mentioned in FIGS. 1 to 3, which carries two gripping needles 8, is arranged in a groove-shaped recess 17 at the outer end 6 of a gripping finger 4, 5 and is pivotable about an axis 18 arranged essentially perpendicular to the effect of the holding force and perpendicular to the direction of an imaginary connecting line between the two gripping needles 8 on the gripping fingers 4, 5. In this way, manufacturing tolerances on the gripping unit itself or on the element 2 to be gripped (a microtiter plate according to FIGS. 4 to 6 is again shown in FIG. 7) can be easily compensated for. Within certain limits, different surface configurations, such as the elevation 15, can be tolerated when the gripping needles 8 are in contact. According to FIG. 7, however, the distance between the gripping needles 8 is selected so that they grip the microtiter plate or the element 2 laterally next to the elevation 15.

The needle rocker 9 and / or the holding of the gripping needles 8 in the needle rocker 9 itself can also be made elastic in a manner not shown here, or the needle rocker 9 can be elastically supported with respect to the gripping fingers 4, 5 or the groove 17, which improves safe holding or gripping.

FIG. 9 shows, similarly to FIG. 1, a somewhat different gripping finger 4, the attachment of which to the gripper (not shown) even here via four to be inserted into holes 19 Screws. The connection of the two gripper finger parts is indicated at 20. At the outer end 6, a needle rocker 9 with two spaced gripping needles 8, which can be pivoted about an axis 18, can again be seen in a groove 17. A microtiter plate is again indicated as the element 2 to be gripped, which here also has a lateral elevation 15, next to which the ends of the two gripping needles 8 engage.

The gripper fingers shown and discussed can in principle be mounted on all robots provided with a corresponding gripper; so-called servo grippers are preferred, however, which enable the gripping force to be controlled. In particular, all microtiter plates currently available on the market can be gripped or handled. The plates can be attacked correctly with or without a lid. The lid can be removed from the corresponding plate or placed on it. The plates themselves can be gripped or held not only in the vicinity of their axes but also in the vicinity of their edges in a stable and secure manner without fear of tipping. The microtiter plates can be removed from or placed in all common pallet configurations, provided that there is only a certain edge distance (preferably about 9 mm) between the individual plates.

The main advantage of this new gripper finger design lies in the precise and thus ultimately positive engagement of the elements to be handled by means of gripper needles, as a result of which the elements to be held, with the gripping force of the gripper mechanism set to the same extent, can be moved much less easily compared to the gripper fingers than with the previously known ones Gripping fingers, which act flatly and frictionally on the elements to be held.

Claims

Claims:

1. Gripping unit for handling robots, in particular for gripping essentially cuboidal elements made of relatively light material, such as microtiter plates, with at least two gripping fingers, which are arranged on a gripper so as to be controllable relative to one another and which have holding elements, characterized in that the holding elements (7, 7 ' ) Have gripping needles (8) which rest with their ends (10) essentially point-like on the element (2) to be gripped and hold it positively under the effect of the holding force exerted by the gripper (1).

2. Gripping unit according to claim 1, characterized in that a holding element (7) has two gripping needles (8) on a common needle rocker (9) which is substantially perpendicular to the effect of the holding force and to the direction of an imaginary connecting line between the two gripping needles (8) on the gripping finger (4, 5) arranged axis (18) is pivotable.

3. Gripping unit according to claim 1 or 2, characterized in that the needle rocker (9) and / or the holder of the gripping needles (8) is elastic.

4. Gripping unit according to claim 2 or 3, characterized in that the needle rocker (9) with respect to the gripping finger (4,5) is elastically supported.

5. Gripping unit according to claim 2 to 4, characterized in that on two interacting gripping fingers (4,5) on the one hand a holding element (7) with a two gripping needles (8) carrying needle rocker (9) and on the other hand a holding element (7 ¹ ) with one fixed individual gripping needle (8) is arranged.

6. Gripping unit according to one of claims 1 to 5, characterized gekennzeich¬ net that the gripping needles (8) and / or the holding elements (7,7 ') carrying gripping fingers (4,5) are bent and / or cranked.