DE20216546U1 - Motor vehicle body section conveyor for production line has carriages with flexible cable drive having manual control operation - Google Patents

Abstract

The motor vehicle body section conveyor for a production line with multiple spaced working stations (25-27) has rail paths (4) for transport carriages (10). The carriages have a reversible and manually operated stationary drive (6) with a flexible elastic drive cable. The carriages (10) each have a floating and manually positionable gripper (19) for the workpieces.

Description

Applicant: KUKA Schweissanlagen GmbH

Blücherstrasse 144 86165 Augsburg

Representatives: Patent attorneys

Dipl.-Ing. H.-D. Ernicke

Dipl.-Ing. Klaus Ernicke

Schwibbogenplatz 2b

86153 Augsburg / Germany

Date: 25.10.2002

File: 772-989 er/ge

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DESCRIPTION

Transport facility

The invention relates to a transport device for workpieces, in particular for body components, which is used in production plants with several work stations arranged one behind the other.

In practice, fully automated transport systems are known as so-called pick-and-place systems. The conveyors have their own drives, are manufactured with high precision and can be positioned very accurately.

Such systems are expensive and are primarily intended for fully automated production plants. They are too complex for simpler applications with manual operation.

WO-A-98/06177 deals with an assembly system in which the workpieces are transported on a flexible transport chain. The workpieces are arranged on workpiece carriers which are connected to one another in a rotatable manner and form the chain links. The workpiece carriers are therefore part of the transport chain. Furthermore, the transport chain is driven in a rotating manner and is not reversible. In addition, the transport chain cannot be operated manually.

It is not suitable for the transport of bodywork components.

DE-A-196 28 556 shows a press linkage with a multi-axis transport robot. This can be moved back and forth between the presses on a support beam and also has a swivel arm with two parallel axes of rotation.

Swivel axes can be coupled to each other in terms of drive.

It is an object of the present invention to provide a cost-effective transport device which is particularly suitable for applications with manual operation.

The invention solves this problem with the features in the main claim.

The claimed transport device can be manufactured with little construction effort using standard components. This makes it particularly cost-effective. In contrast to the previously known transport devices, simple components are also used, in particular a manually operated and stationary drive with a flexible drive means, e.g. a cable pull, with which the transport carriages guided in a form-fitting manner on the rail track can be reversibly moved back and forth between the work stations.

For the preferred applications in which one or more operators are present at the workstations, the positioning accuracy of the transport trolleys and their drive can be relatively low. The operator can manually compensate for any incorrect positioning using a floating bearing of a gripping device on the transport trolley. This offers additional simplification and streamlining options for the transport device.

The transport carriages can be coupled to one another to form a transport train, which is moved back and forth between the work stations or the workpiece holders located there, whereby the workpieces are simultaneously moved one station further and in cycles in the forward stroke. Only when

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If the workpieces are connected to the gripping device at all of the work stations mentioned, the transport device can be started manually and carry out the transport stroke to the next station. The same applies to the return stroke of the empty transport trolleys, which can only be carried out after all of the workpieces have been delivered to the respective workpiece holders. The transport movement is possible thanks to the approval required for this by all operators involved. In this way, complex safety measures can be reduced and simplified.

The transport device in question also has the advantage of being able to negotiate curves, whereby any lateral offsets of the transport carriages that may occur when cornering can also be compensated for by the preferably two-axis floating bearing of the gripping device. The drive can also be maintained just as easily on a single or multiple curved rail track as on a straight rail track. The ability to negotiate curves has advantages in terms of greater positioning freedom for the work stations or their workpiece holders. The transport device is more flexible and can be adapted more easily and better to the local conditions of the production plant.

Further advantageous embodiments of the invention are specified in the subclaims.

The invention is illustrated by way of example and schematically in the drawings. In detail:

Figure 1: a transport device with a straight

Railway track in side view and

Figure 2: another transport device with a curved rail track in plan view.

Figures 1 and 2 each show a transport device (1) for workpieces (2), which are preferably vehicle body components. These are in particular sheet metal parts from body shells. Alternatively, the workpieces (2) can also be of any other type and design.

The transport device (1) serves a production system which has several work stations (25, 26, 27) arranged one behind the other, between which the workpieces (2) are transported in cycles and step by step. Operators (23) are present within the work stations (25, 26, 27) in order to take the necessary control and operating measures for the transport device (1). Within each work station (25, 26, 27) there is at least one workpiece holder (3) at which the workpieces (2) are delivered or picked up again after the machining process takes place in the work station (25, 26, 27). The workpiece holders (3) have suitable, preferably semi- or fully automatic, driven and controllable clamping and fixing means (not shown) for clamping the workpieces (2) in the position required for machining.

The work stations (25, 26, 27) are only shown schematically in Figure 1. The first work station (25) in the transport direction (28) is, for example, a loading station to which the workpieces (2) are fed from outside and introduced into the production system. The next work station (26) in the transport direction (28) is, for example, a processing station in which joining operations, e.g. welding, gluing, assembly or the like, are carried out. Alternatively, any other processing or handling processes can also take place. In the last work station (27), the workpieces (2) are again discharged from the production system. Deviating from this simplified embodiment, the number, sequence and design of the work stations (25, 26, 27) can vary as desired. Such work stations (25, 26, 27) are also present in the embodiment in the figure, where they are not shown in more detail for the sake of clarity.

The transport device (1) consists of a rail track (4) on which one or more transport carriages (10) are guided in a form-fitting manner and are moved back and forth in cycles by means of a stationary drive (6). The rail track (4) is straight in the embodiment shown in Figure 2. Figure 2 shows a variant with a curved rail track (4).

The rail track (4) preferably consists of two parallel rails on which the transport carriages (10) roll by means of lateral wheels (13). In the embodiment shown, the transport carriages (10) have a simple cubic housing for accommodating a delivery device (15) explained below and four wheels (13) each. The rails have a cross-section, for example, of a railroad-like rod profile, with the positive lateral guidance being formed by flanges (14) on the wheels (13).

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In the embodiment shown, the transport carriages (10) roll upright on the rail track (4). Alternatively, they can also be arranged hanging. In a further modification, the rail track (4) can be designed as a monorail arrangement or have any other type and design of rail guide. The design shown with parallel rails is, however, particularly cost-effective. In a further modification, the positive lateral guidance can be created in a different way, for example by profiling the rails and guiding the wheels (13) laterally. The design of the transport carriages can also be modified as desired.

The rail track (4) is arranged on a stationary frame (5). In the embodiment shown, the rail track (4) is located at a distance above the hall floor and the workpiece holders (3). The frame (5) has several posts or stands arranged on both sides of the rail track (4), which are connected to one another by cross members and/or longitudinal members. These cross members or longitudinal members are located above the rail track (4) and the transport carriage (10) and therefore do not impede the transport path. The rail track (4) is preferably attached to the posts or stands, but can also be arranged and mounted in any other desired manner. In the variant of Figure 1, longitudinal and cross members are present. In the modification of Figure 2 with the curved track, preferably only cross members are present, which together with the posts form support portals and are connected to one another by the rail track (4).

The drive (6) consists of a stationary motor (7) which reversibly drives a flexible and tensile drive means (8), e.g. a cable pull or a chain pull. The motor (7) can be, for example, an electric motor with a gear and cable pulley or

- 7 chain pinions
for the drive means (8).

The flexible drive means (8) is arranged in a closed loop that extends over the length of the rail track (4) and is attached to both ends of the transport carriage (10) or a transport train (24) formed by several transport carriages (10). The drive means (8) thus acts as a pulling element that pulls the transport carriage(s) (10) forwards or backwards depending on the direction of rotation of the motor (7).

To form a loop, several deflections (9), e.g. freely rotating deflection rollers, are provided on the frame (5) for the drive means (8). In Figure 1, the deflections (9) and the motor (7) have horizontal axes to form a standing loop, with the deflections (9) and the motor (7) located above the rail track (4) and the transport carriage (10) on the frame (5). In the variant of Figure 2, the deflections (9) and the motor (7) have vertical axes, forming a horizontal loop of the drive means (8). The deflections (9) are present in such a number and arrangement that the drive means (8) can essentially follow the curved rail track (4).

In particular, there are deflections (9) at both ends of the rail track (4) in the middle area between the rails in order to align the drive means (8) essentially along the rails and to maintain this alignment for all travel positions. In this variant, the motor (7) is positioned at one end of the rail track (4) and arranged on the side of the frame (5) or the rail track (4).

In the simplest embodiment, the transport device (1) can have a single transport carriage (10) that transports the workpieces (2) between two or more work stations (25,26,27).

However, this makes transport routes and times relatively long. In the preferred embodiment, several transport carriages (10) are connected to one another to form a transport train (24) using preferably rigid couplings (12). The number of transport carriages (10) is one less than the number of work stations (25, 26, 27) or workpiece holders (3). The couplings (12) can, for example, be articulated connecting rods which keep the transport carriages (10) at a constant distance from one another. The distances between the carriages are the same and preferably correspond to the distances between the work stations (25, 26, 27) or their workpiece holders in the transport direction (28), which are also the same. The transport carriages (10) can have standardized connections (11) at both ends, e.g.

simple bearing eyes for connection to the couplings (12) or the drive means (8).

Each transport carriage (10) has at least one gripping device (19) for grasping and transporting the workpieces (2). The gripping device (19) is mounted on a feed device (15) of the transport carriage (10) preferably in a floating manner on two axes and can be pushed by the operator (23) into the desired position relative to the workpiece (2) or the workpiece support (3). The floating mounting (20) is preferably provided in the two horizontal spatial axes.

The feed device (15) can have one or more axes of movement for moving the gripping device (19). In the embodiment shown, this is a schematically shown lifting device (17) which is equipped with a suitable lifting means (18), e.g. a lifting column and with a drive. Alternatively or additionally, the feed device (15) can have a rotating device (16) with which the gripping device (19) can be rotated to reorient the workpieces.

(2) can be rotated about the vertical axis, preferably the longitudinal axis of the lifting means (18). The rotating device (16) and the lifting device (17) have suitable, preferably electric motor drives for this purpose, which can be controlled by a system control (not shown) or manually by the operator (23) via limit switches or in another simple way. This allows the gripping device (19) and the workpiece (2) to be raised or lowered to the desired height by motor and, if necessary, pivoted into the desired rotational position. The floating bearing (20) is present, for example, between the lifting means (18) and the gripping device (19).

The gripping device (19) consists of a gripper frame (21) with one or more suitable and manually operated clamps (22) for the workpieces (2). In the simplest embodiment, the clamps (22) are opened and closed purely mechanically and by hand.

For this purpose, they can be designed as toggle clamps, for example. Alternatively, the clamps (22) can have their own drives, e.g. pneumatic cylinders or the like.

The transport device (1) preferably consists of standardized mechanical engineering components. This applies to the drive (6), the frame (5), the transport carriages (10) and the feed device (15). The motor-driven components have simple controls that are operated by the operator (23) in a suitable manner, e.g. by pressing a button. The transport device (1) can also have a system control with a logic circuit that stores the incoming control signals, compares them and only enables the transport function when uniform control signals are received at all work stations (25, 26, 27) that are currently being operated.

- 10 -

The transport device (1) shown in both variants works as follows:

New workpieces (2) are transferred in a suitable manner from the outside to the first work station (25) and its workpiece holder (3). This can be done by means of a conveyor device or by hand. The workpieces

(2) are positioned correctly on the workpiece holder

(3) is positioned. For transport to the next processing station (26), the transport train (24) with the rearmost transport carriage (10) is positioned above the workpiece (2) by the drive (6). The gripping device (19) is either controlled automatically or lowered onto the workpiece (2) under manual control by the operator (23). With the help of the floating bearing (20), the operator (23) aligns the gripper frame (21) in the required position relative to the workpiece (2) and then closes the clamps (22). After completing this activity, he signals the release to the system control by pressing a button on a key or similar. If the release is also signaled by the operators (23) (not shown) at the other work stations (26, 27), the clamped workpieces (2) are raised to the transport position shown in Figure 1.

The transport carriages (10) then move one station further. In the neighboring station, the workpiece (2) is then lowered by the gripping device (19) onto the workpiece holder (3) there. The operators (23) manually open the clamps (22) and again give a release signal. This also automatically activates the clamping and fixing elements on the workpiece holder (3). As soon as all affected work stations (25,26,27) have given the release, the gripping devices (19) of the transport carriages (10) are raised again, and the transport carriages (10) then move one station back to their starting position. They then wait with the gripping devices raised.

- 11 -

(19) until the machining operations at the affected work stations (25,26,27) are completed and the next transport cycle can begin. Upon manual release by the operator, the gripping devices (19) are then lowered again and the automatic clamping and fixing elements on the workpiece holders (3) are opened.

The transport cycle described above takes place at all work stations (25, 26, 27) simultaneously. The workpieces (2) are transported one station at a time. In Figure 1, this is indicated schematically by the dashed representation of the second transport carriage (10) and its gripping device (19) in the last work station (27). From this last work station (27), the workpiece (2) is removed either in a suitable manner by means of a conveyor or by hand and passed on for further processing.

- 12 REFERENCE SYMBOL LIST

1 transport device

2 Workpiece, body component 3 Workpiece holder

4 Railroad

5 Frame, stand

6 Drive

7 Engine

8 Drive means, cable pull

9 Deflection

10 wagons, transport wagons

11 Connection

12 Clutch ¹ S 13 Wheel

14 wheel flange

15 Delivery device

16 Rotating device

17 Lifting device

18 Lifting equipment, lifting column

19 Gripping device

2 0 floating storage

21 Gripper frame

22 Tensioner 23 Operator

24 Transport train

25 Workstation, loading station

26 Workstation, processing station

27 Work station, unloading station 28 Transport direction

Claims (19)

1. Transport device for workpieces ( 2 ), in particular body components, in production plants with several work stations ( 25 , 26 , 27 ) arranged one behind the other, characterized in that the transport device ( 1 ) has one or more transport carriages ( 10 ) guided in a form-fitting manner on a rail track ( 4 ) and a reversing and manually operated, stationary drive ( 6 ) with a flexurally elastic drive means ( 8 ). 2. Transport device according to claim 1, characterized in that the transport carriage ( 10 ) has a floating and manually positionable gripping device ( 19 ) for the workpieces ( 2 ). 3. Transport device according to claim 1 or 2, characterized in that several transport carriages ( 10 ) are connected to one another by couplings ( 12 ) to form a transport train ( 24 ). 4. Transport device according to claim 1, 2 or 3, characterized in that the transport carriages ( 10 ) have rigid couplings ( 12 ) and fixed distances in the transport train ( 24 ). 5. Transport device according to one of the preceding claims, characterized in that the carriage distances correspond to the distances of the work stations ( 25 , 26 , 27 ) or the workpiece holders ( 3 ) in the work stations ( 25 , 26 , 27 ). 6. Transport device according to one of the preceding claims, characterized in that the rail track ( 4 ) is straight or curved and has a length which is greater than the length of the work stations ( 25 , 26 , 27 ) or workpiece holders ( 3 ) arranged one behind the other. 7. Transport device according to one of the preceding claims, characterized in that the rail track ( 4 ) is arranged on a stationary frame ( 5 ) at a distance above the ground. 8. Transport device according to one of the preceding claims, characterized in that the frame ( 5 ) has a plurality of posts fastened to the ground on both sides of the rail track ( 4 ), which are connected to one another by cross members and/or longitudinal members which are arranged above the rail track ( 4 ). 9. Transport device according to one of the preceding claims, characterized in that the drive means ( 8 ) is arranged in a closed loop extending over the length of the rail track ( 4 ) and is fastened to both ends of the transport carriage ( 10 ) or transport train ( 24 ). 10. Transport device according to one of the preceding claims, characterized in that the drive means ( 8 ) is designed as a cable pull or chain pull. 11. Transport device according to one of the preceding claims, characterized in that the drive ( 6 ) has a stationary motor ( 7 ) and several deflections ( 9 ) for the drive means ( 8 ). 12. Transport device according to one of the preceding claims, characterized in that the loop of the drive means ( 8 ) is aligned with horizontal axes of rotation and upright, wherein the motor ( 7 ) is arranged on the frame ( 5 ). 13. Transport device according to one of the preceding claims, characterized in that the loop of the drive means ( 8 ) is aligned with vertical axes of rotation and horizontally, wherein the motor ( 7 ) is arranged laterally on the frame ( 5 ). 14. Transport device according to one of the preceding claims, characterized in that the transport carriage ( 10 ) has a single- or multi-axis movable delivery device ( 15 ) for the gripping device ( 19 ). 15. Transport device according to one of the preceding claims, characterized in that the gripping device ( 19 ) is floatingly mounted on the delivery device ( 15 ). 16. Transport device according to one of the preceding claims, characterized in that the delivery device ( 15 ) has a lifting device ( 17 ). 17. Transport device according to one of the preceding claims, characterized in that the delivery device ( 15 ) has a rotating device ( 16 ). 18. Transport device according to one of the preceding claims, characterized in that the gripping device ( 19 ) has a gripper frame ( 21 ) and one or more manually operable tensioners ( 22 ). 19. Transport device according to one of the preceding claims, characterized in that the rail track ( 4 ) has two parallel rails with a rod profile, wherein the transport carriages ( 10 ) have lateral wheels ( 13 ) with wheel flanges ( 14 ) for lateral guidance.