GB2045720A

GB2045720A - Automatic apparatus for holding workpieces or work tools

Info

Publication number: GB2045720A
Application number: GB8007294A
Authority: GB
Original assignee: Jungheinrich Unternehmensverwaltung KG
Current assignee: Jungheinrich AG
Priority date: 1979-03-05
Filing date: 1980-03-04
Publication date: 1980-11-05
Also published as: DE2908523A1; SE8001330L; NO800619L; FR2450673A1

Abstract

Automatic apparatus which has a manipulation device (14) for receiving a workpiece or a work tool includes a turret (3) which has a bottom plate (4) which is rotatable with respect to a base arrangement and a carrier (5) extending upwardly from the bottom plate. An upper-arm like lever (6) is pivotally mounted, about a horizontal axis (8), on the carrier (5) and a fore- arm like lever (11) is pivotally mounted, about a horizontal axis (10), on a free end of the lever (6) and carries the manipulation device (14). The levers (6) and (11) are so arranged and constructed that the fore-arm like lever (11) is pivotable about its axis (10) on the upper-arm like lever (6) through an angle of 360 DEG . The manipulation device (14) is mounted on the fore-arm like lever (11) for rotation about and adjustment longitudinally of the longitudinal axis thereof. <IMAGE>

Description

SPECIFICATION Automatic apparatus for holding workpieces or work tools The invention relates to automatic apparatus (robots) having a controllable manipulation device for holding a workpiece of a work tool.

The manipulation device can be constructed as a gripper which, for example, takes a workpiece and changes its location. It can also serve as a tool carrier for, for example, a welding torch.

Such automatic apparatus is used in manufacturing with a freely programmable electronic control. This invention is particularly concerned with the mechanical multiple shaft construction of such apparatus which provides a large spherical working space and in a particular manner, permits the undertaking of the manipulation of objects within its own contours.

Different such apparatus are classified in accordance with the number and arrangement of the shafts. One distinguishes the mechanical construction particularly in accordance with the basic shafts with which the workpiece or the work tool is guided within the working zone and in accordance with manipulation shafts which serve essentially for changing the spatial orientation of the workpiece or the work tool.

It is an object of the present invention to improve apparatus of the aforementioned type in such a way that a simpler mechanical construction is obtained which permits, while maintaining good stability, the construction of different such apparatus through selective putting together of sub-assemblies, as well as speedy manipulation within substantially the whole working space.

In accordance with the present invention there is provided automatic apparatus having a controllable manipulation device for receiving a workpiece or a work tool and comprising a turret having a bottom plate movable with respect to a base arrangement and a carrier extending upwardly from the bottom plate, an upper-arm like lever mounted on the carrier about a first shaft parallel to the base arrangement, a fore-arm like lever pivotably mounted on an end of the upper-arm like lever about a second shaft parallel to said first shaft and having the manipulation device mounted thereon for rotation about and adjustment longitudinally of the longitudinal axis thereof, said fore-arm like lever being pivotable about the second said shaft through an angle of 360*.

In this way, the fore-arm like lever is pivotable through in a downward direction and it may also be moved about a larger angle than 360 . At the same time apparatus is created which is assemblable in very many different ways from the sub-assemblies which can be developed in various size ranges.

A particularly advantageous construction, with regard to stiffness as also with reference to the exchangeability of assemblies and the overhung support with respect to each other, is provided when all assemblies in the form of the turret, the upper-arm like lever and the fore-arm like lever are constructed hollow bodies having load-supporting external shells in lightweight construction and are supported in overhung relationship to each other by way of wire ring ballbearings having large diameter.

In this way a particularly good connection stiffness with lightweight construction provides the possibility of bringing the drive means into the interior of the hollow bodies.

These hollow bodies have advantageously simple geometric shapes which are constructable through welding adhesives, screws or folding of sheet metal. Preferably the hollow bodies are constructed from fibre reinforced plastics. In this connection the hollow bodies may have, at least in the zone of the support points, relatively large form plane sidefaces on which wire ring ballbearings can relatively easily be located. In this way there are advantageously provided wire ring ballbearings having a diameter which corresponds approximately to 2/5 of the length from the bearing middle point to the manipulation device at its maximum extent and these can form effective drive means at the same time.

The wire ring ballbearings can unite the functions of the support and of the introduction of the turning moment for the establishment of the rotary movement. Preferably, a drive motion is transferred from the carrier to the upper-arm like lever and in this to the rotating shaft of the fore-arm like lever which contains drive motors for the manipulation shafts.

With reference to the already mentioned tube in the fore-arm like lever, a particular embodiment of the invention lies in that, within this tube, further central transfer rods, of which at least one is a tube, are provided with separate operational drive motors within the fore-arm like lever which permit an adjustment of the manipulation device about several axes. This is an example where a hollow body can advantageously be used. In this connection it is preferred that the fore-arm lever is supported on the upper-arm like lever so that the operational drive motors are arranged as counterweights with respect to the manipulation device. In this way one automatically obtains a counterweight compensation which provides essentially light movability.

In an advantageous embodiment the turret is constructed with an L-shaped cross-section and the upper-arm like and fore-arm like levers are mounted on a side of the upwardly extending carrier in such a way that the central longitudinal axis of the fore-arm like lever coincides with or intersects the vertical central axis of rotation of the bottom plate of the turret.

It is particularly preferred that the fore-arm like lever is in practice pivotable overhead so that it can stretch over a zone which is also defined through the pivotability of the forearm like lever and which embraces practically all areas of a working space. This embodiment is particularly compact.

It is also preferred that the turret is supported on a turntable and is rotatable in a known way which defines the vertical central line as the axis of rotation.

In accordance with another advantageous embodiment the turret is arranged on a linear guide. In this way, apart from the guide means, similar drive means to the drive of the turret can be used in the linear direction, that is in a straight line. This underlines the variability of installation of the present elements. It remains possible to set the above-mentioned base arrangement itself on a linear guide so that then the turret or rotatable turret is arranged movably on it in the described manner. The above-indicated pivotability of the fore-arm like lever overhead is valuable then as a preferred construction for all embodiments.

With particular advantage a spring (a steel or a gas spring) is arranged between the turret and the upper-arm like lever which is tensionable during pivoting of the upper-arm like lever out of the parallel shaft arrangement and forms a balance weight. In this way a balance weight can be obtained with simple means, taken also in connection with the lightweight construction of the self-supporting hollow body which has great stiffness for small weight.

In addition, in connection with wire ring ballbearings, lies a particular construction in that, as drive means, toothed drives in the form of gears, toothed belts or chains can be provided which preferably cooperate with the inner or outer ring of a wire ring ballbearing.

To this end may serve an outer or inner toothing on one of the bearing rings, for example. Because of the preferred. relatively large, diameter of the bearing a reduction of the order of approximately 1:10 can be obtained directly in the drive. In this way the requirements as to further stepdown drives are simplified. The relatively large diameter is, for example, 6QO mm in relation to an extended arm length of 1.5 m. The use of such wire ring ballbearings has a further advantage since the passage of hydraulic and pneumatic lines or electric cables from the bottom plate up into the fore-arm like lever is simplified.

In this connection there is an additional advantage in the hungover arrangement in that a large working space for the tools is obtainable.

Inasmuch as, hereinafter, different embodiments are described, this underlines the advantage running throughout that the different embodiments are constructed by the putting together of similar assemblies. In particular the fore-arm like lever presents a self-contained unit which also accepts the operational drive motors for the working device in particular with reference to its movements about diffent axes.

The invention will now be explained in more detail with reference to exemplary embodiments which are illustrated in the accompanying drawings, in which: Figure 1 is a schematic front view of automatic apparatus incorporating a manipulation device; Figure 2 is a side view of the apparatus of Fig. 1 from the left; Figure 3 is a plan view of the apparatus of Fig. 1; Figure 4 is a schematic illustration for explaining the working space of the manipulation device of the apparatus of Figs. 1 to 3; Figure 5 is a plan view of a linearly movable automatic apparatus incorporating a manipulation device; Figure 6 is a view corresponding to that of Fig. 5 of another embodiment of automatic apparatus according to the invention; Figure 7 is a side view of a fore-arm like lever in section.

Figure 8 is a view corresponding to that of Fig. 7 of a modified construction of fore-arm like lever.

In all the Figures the same parts are shown with the same reference numerals.

According to Figs. 1 to 3 a base arrangement 1 is provided on which a rotary turret 3 is rotatably mounted by means of a turntable or wire ring ballbearing 2. The turret includes a bottom plate 4 extending parallel to the base arrangement and a carrier 5 extending perpendicularly to the plate 4. The rotary turret 3 is constructed, in accordance with Figs. 1 to 3, with a cross-section, as seen in the view according to Fig. 3, of L-shape, that is the upwardly extending carrier 5 is located at an edge of the bottom plate 4.

An upper-arm like lever 6 is arranged on the carrier 5. It is mounted on the inner side of the carrier 5 by way of one end thereof on a turntable or wire ring ballbearing 7 so that a support of the overhung type is present and the lever 6 is rotatable about a horizontal axis 8 of rotation.

In the embodiment according to Figs. 1 to 3 in which the rotary turret 3 has an L-form shape, a fore-arm like lever 11 is supported on the side of the upper-arm like lever 6 remote from the carrier 5 and on the free end thereof by means of a further wire ring ballbearing 9 and is pivotable about a horizontal axis 10 of rotation. The lever 11 is constructed as a two-armed lever so as to extend to either side of the axis 10 in accordance with Figs. 1 and 2 and out of its, with reference to Fig. 1, right hand end extends a tube 1 2 on which is arranged a pivot head 1 3 which carries a manipulation device 1 4. The particular construction of the fore-arm like lever 11 is described with reference to Figs. 7 and 8.

Fig. 1 shows how the fore-arm like lever 11 having the pivot heat 1 3 and the manipulation device 14, i.e. practically a hand and gripping fingers, can be swung through in a downward sense. Accordingly, manipulation steps can be carried out particularly quickly.

This movement is shown in Fig. 1 by the double arrow between the spatial poins A and B. The paths of travel, which can be any one of a number of different trajectories, saves the long travel path over the top. Furthermore it means that manipulation operations can take place in the immediate vicinity of the turret so that there is almost no inward limitation of the working space as is described later with reference to Fig. 4.

With reference to Figs. 1 to 3, there is a vertical axis 1 5 of rotation for the bottom plate 4. On the bottom plate is a drive motor 16, which drives a shaft guided through the bottom plate, and a gear 1 7 arranged on the shaft engages with a turntable 1 8 on a wire ring ballbearing 2 or a toothing on this.

Correspondingly, a further drive motor 1 9 is arranged on the carrier 5 which drives a shaft 20 extending therefrom and a gear arranged thereon engaged in an external toothing of the wire ring ballbearing 7, in order to pivot the upper-arm like lever 6.

Aligned with the axis 8 of rotation with the drive shaft aligned with this axis is a further drive motor 21 arranged in the carrier 5. A transmission 22 passes through the hollow lever 6 and connects the output shaft of the motor 21 to a transmission part 23 on the rotation shaft for lever 11 aligned with the axis 10 so that thereby the fore-arm like lever 11 is pivotable about 360 . In this way a greater movement zone by way of the device is obtainable since the rotation of the fore-arm like lever 11 is summable to the pivoting of the upper-arm like lever 6.

Preferably an abutment 24 is arranged at the free end of the lever 6 for one end of a spring 25 whose other end engages an abutment 26 on the upper end of the carrier 5. In this way there is obtained, with reference to the abutments on the one hand and to the axis 8 of rotation of the upper-arm like lever 6 on the other hand, a type of deadpoint device by which the spring 25 is tensioned during pivoting out of the axially aligned position so that with increasing pivoting an increased tensioning of the spring is obtained as a balance weight.

The device according to Figs. 1 to 3 can create a working space of spherical-type shape corresponding to a peripheral line 55 as shown in Fig. 4. If the upper-arm like lever 6 and the fore-arm like lever 11 are located in the outstretched position the manipulation device can be moved along a spherical-like space within the peripheral line 55 if the lever 6 is rotated about the axis 8 of rotation and the turret 3 is rotated also about the axis 1 5 of rotation. A sideways pivoting of the forearm like lever 11 about the axis 10 of rotation leads to a movement possibility up to the contour 27 whereby the intermediate positions can be obtained also by way of movement in the opposite sense.

In accordance with Fig. 5 a turret 3' according to Fig. 1 is arranged on a linear guide 35 with corresponding gripping rails 36, 37, whereby, for example, a toothed rack drive rail 38 is arranged between the rails 36, 37.

The pinion of the drive motor 1 6 engages with this so that thereby practically the same assemblies are used as in the embodiment of Figs. 1 to 3 whereby only the support and guidance arrangement of the bottom plate 4 are changed.

In accordance with Fig. 6 a corresponding linear guide 35 is provided whereby nevertheless the turret 3' is as also illustrated in Fig. 1 with the table or wire ring ballbearing 2 and is arranged on a guide plate 39 which is movable backwards and forwards on the linear guide 35. In this way the rotatability of the turret 3 encloses a further working area.

A particular assembly in the described embodiment is that of the fore-arm like lever 11.

This is, in accordance with Figs. 7 and 8, constructed as a flat walled hollow body having a widening in the zone of the axis 10 on which the wire ring ballbearing 9 is arranged.

One can see that, in the inerior of the hollow body 40, a bearing 41 and, at the outwardly hanging end 42, a further bearing 43 are arranged in which the tube 1 2 with the pivot head 1 3 and the manipulation device 1 4 are rotatably journalled. On this tube in the interior of the lever 11 a toothed gear 44 is arranged which stands in engagement with a pinion 46 on the output shaft of a motor drive unit 45. On the interior of the tube 1 2 a further tube 47 is rotatably journalled in a non-illustrated manner, on which the pivot head 1 3 is arranged for its rotation about an axis 48 perpendicular to the longitudinal axis of the tube 11.This tube is driven by a toothed wheel 49 and a pinion 50 from a drive motor 51 at the end of the fore-arm like lever 11 remote from the end 42. This tube 47 is passed through by a drive shaft 52 which is correspondingly driven by a gear 53 from a drive motor 54 at the same end as the drive motor 51 and which moves the pivot head 1 3 about a further axis which lies perpendicular to the axis 48. In this way it is obtained that the manipulation device 1 4 is rotatable about up to three manipulation axes.

If only two manipulation axes are required then the third rotation shaft which is driven by the drive motor 51, controls for example the opening and closing movement of the manipulation device 14. In the embodiment according to Fig. 8 the gear 53 is dispensed with.

The spatial location particularly of the drive motors 51 and 54 in Fig. 7 and the drive motors 45, 51, 54 in Fig. 8 form a balance weight with reference to the axis 10.

Claims

1. Automatic apparatus having a controlla ble manipulation device for receiving a workpiece or a work tool and comprising a turret having a bottom plate movable with respect to a base arrangement and a carrier extending upwardly from the bottom plate, an upper-arm like lever mounted on the carrier about a first shaft parallel to the base arrangement, a forearm like lever pivotably mounted on an end of the upper-arm like lever about a second shaft parallel to said first shaft and having the manipulation device mounted thereon for rotation about and adjustment longitudinally of the longitudinal axis thereof, said fore-arm like lever being pivotable about the second said shaft through an angle of 360 .

2. Apparatus according to claim 1 having basic shafts, with which the workpiece or work tool is movable within a working zone, and manipulation shafts for changing the spatial orientation of the workpiece or work tool, the drive means for the manipulation shafts being built in to the upper-arm like lever which is constructed as a hollow body.

3. Apparatus according to claim 2 wherein, in respect of the manipulation shafts, a shaft is constructed as a tube supported in the axial direction which carries at an unsupported end thereof a pivot head having at least one further rotary shaft which is in connection with an associated internal drive.

4. Apparatus according to one of claims 1 and 2, wherein all the assemblies, in the form of the turret, the upper-arm like lever and the fore-arm like lever, are constructed as hollow bodies having load carrying external shells in lightweight construction and are supported on each other in an overhung manner through wire ring ballbearings having large diameter.

5. Apparatus according to one of the claims 2 to 4 wherein the hollow bodies form simple geometric shapes which consist of sheet metal or fibre reinforced plastics and have a plane sideface at least in the zone of the support points.

6. Apparatus according to claim 5 having large sized place sidefaces on said hollow bodies and wire ring ballbearings having a diameter which corresponds approximately to 2/5 of the length from the middle point of the supports to the manipulation device at its maximum extent.

7. Apparatus according to one of the claims 1 to 6 wherein a drive motion is transferred from the carrier to the upper-arm like lever and in this way to the rotating shaft of the fore-arm like lever which contains drive motors for the manipulation shafts.

8. Apparatus according to claim 3 and to claim 7 when dependent on claim 3, wherein, within the tube there are provided further central transfer rods at least one of which is a tube and which have separate operational drive motors within the fore-arm like lever which allow an adjustment of the working device about several axes.

9. Apparatus according to claim 8, wherein the fore-arm like lever is supported on the upper-arm like lever so that the operational drive motors are arranged as counterweights with respect to the manipulation device.

10. Apparatus according to any one of claims 1 to 9 wherein the turret is constructed with an L-shaped cross-section and the upperarm like and fore-arm like levers are mounted on a side of the upwardly extending carrier in such a way that the central longitudinal axis of the fore-arm like lever coincides with or intersects the vertical central axis of rotation of the bottom plate of the turret.

11. Apparatus according to any preceding claim wherein the turret is supported on a turntable on which it is rotatable and which defines the vertical central axis as the axis of rotation of the turret.

1 2. Apparatus according to any one of claims 1 to 10, wherein the turret is arranged so as to be movable sideways on a linear guide.

1 3. Apparatus according to any one of claims 1 to 10 wherein the base arrangement is mountable on a linear guide.

14. Apparatus according to any one of the preceding claims wherein the fore-arm like lever is pivotable overhead.

1 5. Apparatus according to one of the preceding claims wherein, between the turret and the upper-arm like lever there is located a spring (a steel or a gas spring) which is put under tension during pivoting the upper-arm like lever out of the parallel axis position arrangement and creates a balance weight.

16. Apparatus according to any one of the preceding claims wherein, as drive means, toothed drives with gears, toothed belts or chains are provided which cooperate with the inner or outer ring of a wire ring ballbearing.

17. Apparatus according to any one of the preceding claims wherein the upper-arm like and fore-arm like levers are constructed as distinct sub assemblies which are capable of substitution with respect to each other.

1 8. Automatic apparatus having a controllable manipulation device substantially as hereinbefore described with reference to the accompanying drawings.