Method and conveying system for the simultaneous transport of elongated workpieces and workers in a production line

Abstract

A method for the transport of elongated workpieces and workers, in a production line which has a rectilinear production section. A plurality of conveyor trolleys, which respectively have an assembly platform that extends over the whole of the conveyor trolley length and is accessible for workers, move in the rectilinear production section jointly along a direction of conveyance and form a convoy in which the assembly platforms of adjacent conveyor trolleys adjoin one another in an at least substantially gap-free manner. The workpieces are arranged in such a way on the assembly platforms that a longitudinal direction of the workpieces is arranged at an angle between 25 and 65, and preferably of about 45, to the direction of conveyance.

Claims

1. A method for the simultaneous transport of elongated workpieces and workers in a production line which has a rectilinear production section, the method comprising: moving a plurality of conveyor trolleys in a rectilinear production section of a production line jointly along a direction of conveyance, each conveyor trolley having an assembly platform that extends over a whole length of the conveyor trolley and is accessible for workers, wherein the plurality of conveyor trolleys form a convoy when moving in which the assembly platforms of adjacent conveyor trolleys adjoin one another in an at least substantially gap-free manner, wherein workpieces are arranged in such a way on the assembly platforms of the conveyor trolleys that a longitudinal direction of the workpieces is arranged at an angle between 25 and 65 to the direction of conveyance.

2. The method according to claim 1, wherein the workpieces are arranged on the assembly platforms of the plurality of conveyor trolleys so that a longitudinal direction of the workpieces is arranged at an angle between 40 and 50 to the direction of conveyance.

3. The method according to claim 1, wherein the workpieces are motor vehicles which are to be assembled.

4. The method according to claim 1, wherein the longitudinal axes of the workpieces are arranged parallel to one another in the rectilinear conveying section.

5. A conveying system for the simultaneous transport of elongated workpieces and workers in a production line which has a rectilinear production section, the conveying system comprising: a plurality of conveyor trolleys, each conveyor trolley having a workpiece receptacle and an assembly platform that extends over a whole length of the conveyor trolley and is accessible for workers, wherein the conveyor trolleys move in a rectilinear production section of a production line jointly along a direction of conveyance and form a convoy in which the assembly platforms of adjacent conveyor trolleys adjoin one another in an at least substantially gap-free manner, wherein the workpiece receptacle is configured such that a longitudinal direction of a workpiece to be fastened thereon is arranged at an angle between 25 and 65 to the direction of conveyance.

6. The conveying system according to claim 5, wherein the workpiece receptacle is configured such that the longitudinal direction of the workpiece to be fastened thereon is arranged at an angle between 40 and 50 to the direction of conveyance.

7. The conveying system according to claim 5, wherein the workpiece receptacle has a longitudinal direction which is arranged at an angle between 25 and 65 to the direction of conveyance.

8. The conveying system according to claim 5, wherein each assembly platform has the shape of a rectangle having an aspect ratio V with V<1.2.

9. The conveying system according to claim 5, wherein each assembly platform is divided by the longitudinal axis of the workpiece into two work areas, which are at least substantially triangular, and each of the two work areas has at least one material supply device for the storage of individual parts to be fitted, and for the removal thereof by the worker.

10. The conveying system according to claim 5, wherein in the rectilinear conveying section, the longitudinal axis of the workpieces on the assembly platforms are arranged parallel to one another.

11. The conveying system according to claim 5, wherein each workpiece receptacle is rotatable about a vertical axis.

12. The conveying system according to claim 5, wherein the conveying system has: a) a conveyor line, in which the workpieces are conveyed along a further direction of conveyance such that the longitudinal directions of the workpieces are oriented parallel to the further direction of conveyance, and b) a rotating device, which is designed to rotate the workpiece about a vertical axis before it is fastened on the workpiece receptacle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Illustrative embodiments of the invention are explained in greater detail below with reference to the drawings, in which:

(2) FIG. 1 shows a conveying system known from the prior art, in which a plurality of conveyor trolleys jointly form a pushed convoy;

(3) FIG. 2 shows a conveying system known from the prior art, in which the assembly platforms, in comparison to the conveying system shown in FIG. 1, are narrower;

(4) FIG. 3 shows a conveying system according to the invention, in which motor vehicles to be assembled are arranged obliquely on the assembly platforms;

(5) FIG. 4 shows an initial region of a rectilinear conveying section, in which the conveyor trolleys, prior to entry into the convoy, are laterally offset;

(6) FIGS. 5 and 6 show a variant of the conveying system shown in FIGS. 3 and 4, in which the material supply devices are arranged differently on the assembly platforms;

(7) FIGS. 7 and 8 show the conveying systems shown in FIGS. 5 and 6, yet without the motor vehicles to be assembled;

(8) FIGS. 9 and 10 show an initial region of a rectilinear conveying section at two points in time, between which a workpiece has been rotated with the aid of a rotating device before being deposited on the workpiece receptacle of a conveyor trolley by an overhead conveyor;

(9) FIGS. 11 and 12 show an initial region of a rectilinear conveying section at two points in time, between which a workpiece has been rotated with the aid of a rotatable workpiece receptacle after having been deposited on the workpiece receptacle of a conveyor trolley by an overhead conveyor.

DESCRIPTION OF PREFERRED ILLUSTRATIVE EMBODIMENTS

(10) 1. Prior Art

(11) FIG. 1 shows in a schematic top view a conveying system 10 known from the prior art, in which a plurality of conveyor trolleys 12, in a rectilinear production section 14 of a production line, jointly form a pushed convoy. In the top view can be seen the assembly platforms 16 of the conveyor trolleys 12, which are mounted on bogies (not discernible in top view). Each assembly platform 16 carries a motor vehicle 18 to be assembled and is accessible for workers 20. The assembly platforms 16 respectively have a rectangular shape, wherein the longitudinal axes 24 of the assembly platforms 16 are aligned and run parallel to a direction of conveyance (indicated with an arrow 22), along which the motor vehicles 18 are conveyed by the conveyor trolleys 12 during the assembly.

(12) The assembly platforms 16 further carry material supply devices 26, which, in the represented example, are respectively mounted on the corners of the assembly platforms 16. The material supply devices 26 can be constituted, for instance, by racks, in which parts to be fitted are stored so as to be able to be removed by the workers 20, or can be constituted by pallets, on which materials are stacked. Usually, the material supply devices 26 are configured such that they can be regularly exchanged for newly filled material supply devices 26.

(13) Extending to both sides of the conveyor trolleys 12 are side bands 28a, 28b, which in the represented example are stationary. The side bands 28a, 28b can, however, also be configured as conveyor belts, which move at the same speed as the assembly platforms 16 and are located at the same height as these. The side bands 28a, 28b then actually enlarge the width of the assembly platforms 16 which is available to the workers 20.

(14) To the outside, the side bands 28a, 28b are adjoined by material supply zones 30a, 30b, in which further material supply devices, tools or intermediate stores for the parts to be fitted, and other materials, can be found, as is known per se in the prior art.

(15) In the represented example, the width of the assembly platforms 16 is four metres, and the width of the side bands 28a, 28b and of the material supply zones 30a, 30b is respectively one metre.

(16) As a result, the 8 m width which is in total available for the production line is fully utilized, wherein the assembly platforms 16, by themselves, take up half of the available width.

(17) FIG. 2 shows a similar conveying system 10, in which the aspect ratio of the rectangular assembly platforms 16 is larger. In this example, the assembly platforms have 16 a width of only 3 m, and, in return, a length of 8 m. Owing to the lesser width of the assembly platforms 16, the material supply devices 26 are arranged on the end sides of the assembly platforms 16. The advantage with this dimensioning of the assembly platforms 16 is that the material supply zones 30a, 30b can be wider than in the example shown in FIG. 1. As a result of the greater length of the assembly platforms 16, workers 20 must go back over longer distances, however, should they wish to switch between the motor vehicles 18.

(18) 2. Conveying System According to the Invention

(19) FIG. 3 shows in a schematic top view a conveying system 10 according to a first illustrative embodiment of the invention. The assembly platforms 16 of the conveyor trolleys 12 have the shape of a square having a 5 m side length. The motor vehicles 18 to be assembled are arranged in such a way on the assembly platforms 16 that the longitudinal axes 32 of the motor vehicles 18 is arranged at an angle of 45 to the direction of conveyance 22, wherein the longitudinal axes 32 of all motor vehicles 18 run parallel to one another. In the represented illustrative embodiment, the respective longitudinal axis 32 thereby coincides at least approximately with a plane diagonal of the assembly platforms 16.

(20) Due to this diagonal mounting of the motor vehicles 18, each assembly platform 16 is divided by the motor vehicle 18 into two triangular work areas 34a, 34b, in which the workers 20, despite the material supply devices 26 arranged there, can move freely and safely. In the illustrative embodiment represented in FIG. 3, the material supply devices 26 are arranged along the side edges, running in the direction of conveyance 22, of the assembly platforms 16.

(21) In front of and behind the motor vehicles 18, there remains on each individual assembly platform 16, due to the diagonal arrangement, space for the worker 20. This space is enlarged by virtue of the fact that the sections concerned are adjoined by the triangular work areas 34a, 34b of the adjacent assembly platforms 16 and can be used for the placement of material. Right across the vehicle range, the workers 20 can hence make still better use of the assembly platforms 16 than was previously possible in conveying systems of this type.

(22) The angular position of the motor vehicles 18 calls for a greater width of the assembly platforms 16. Since the workers, however, have a great deal of space in the triangular work areas 34a, 34b, the previously necessary side bands 28a, 28b can be dispensed with. In the represented illustrative embodiment, the assembly platforms 16 are therefore directly adjoined by the material supply zones 30a, 30b. Given a width of the production line of 8 m in total, the material supply zones 30a, 30b can thus, in the represented illustrative embodiment, still respectively be 1.5 m wide. In the material supply zones 30a, 30b there is therefore precisely as much space as in the example, shown in FIG. 2, from the prior art, which there, however, is only possible by the acceptance of very long assembly platforms 16.

(23) In contrast thereto, the assembly platforms 16 according to the invention, in the illustrative embodiment represented in FIG. 3, are 37.5% shorter than in the example, shown in FIG. 2, from the prior art. If a worker 20 switches only between two adjacent assembly platforms, this 3 m difference in length is perhaps not yet of any consequence. If a worker 20, however, has to go back over, for instance, 15 conveyor trolleys 12, this corresponds to a 45 m shortening of the distance to be covered, which has a perceptible impact on the worker 20.

(24) FIG. 4 shows the start of the conveying section 14, in which the conveyor trolleys 12 are initially transported transversely to the direction of conveyance 22 along the transverse direction indicated with the arrow 36, before they enter into the production section 14 and begin their movement along the direction of conveyance 22. For this purpose, the conveyor trolleys 12 possess omnidirectional running gears, so that they can change the direction of conveyance by 90 without the negotiation of bends. As can be seen in FIG. 4, the orientation of the longitudinal axes 32 of the motor vehicles 18, including during conveyance along the transverse direction 36, therefore remains parallel to the longitudinal axes 32 of those motor vehicles 18 which are already in the conveying section 14.

(25) In a representation based on FIGS. 3 and 4, FIGS. 5 and 6 show a variant of the conveying system which is shown there, in which the material supply devices 26 are arranged differently on the assembly platforms 16. Here too, the material supply devices 26 are located in the corners of the triangular work areas 34a, 34b. The distances which must be covered by the workers 20 between the material supply devices 26 and the motor vehicles 18 to be assembled are in this variant somewhat shorter than in the illustrative embodiments shown in FIGS. 3 and 4. The arrangement of the material supply device 26 obliquely or perpendicular to the direction of conveyance 22 somewhat restricts, however, the crossing of the workers 20 onto adjacent assembly platforms 16.

(26) FIGS. 7 and 8 show the conveying systems 10 shown in FIGS. 5 and 6 in a top view, without the motor vehicles 18 which are to be assembled. Workpiece receptacles 38 which are designed to carry the motor vehicles 18 can hence be seen. The workpiece receptacles 38 can be configured in the style of a lifting table and hence be adjustable in height, so that the workers can work on the motor vehicles 18 at different heights. In the represented illustrative embodiment, the workpiece receptacles 38 respectively possess 4 conical recesses 40, in which complementarily shaped projections which are configured on the motor vehicles 18, or on an additional carrier for the motor vehicles 18, can engage. The workpiece receptacle 38 likewise have in total the shape of a rectangle, and a longitudinal axis 42 which runs at an angle of 45 to the direction of conveyance 22 and is aligned with the plane diagonal of the respective assembly platforms.

(27) If the wheels are already fitted on the motor vehicles 18, the motor vehicles can also be placed directly onto the assembly platforms 16. An additional workpiece receptacle 38 is then not necessary.

(28) The conveyor trolleys 12 with the motor vehicles 18 arranged obliquely thereon can advantageously also be used in conveying systems in which the conveyor trolleys do not form a convey in which the assembly platforms of adjacent conveyor trolleys adjoin one another in an at least substantially gap-free manner.

(29) FIGS. 9 and 10 show in a schematic top view an initial region of a rectilinear conveying section 14 at two different points in time. With 44 is indicated the rail of an electric overhead conveyor which crosses the region in which the conveyor trolleys 12 move along the transverse direction 36. In this region, the direction of conveyance of the conveyor trolleys 12 thus runs parallel to the direction of conveyance of the electric overhead conveyor. As can be seen in FIG. 9, the motor vehicles 18 are fastened in such a way to overhead trolleys 46 of the electric overhead conveyor that the longitudinal direction 32 of the motor vehicles 18 is aligned with the rail 44 and thus runs parallel to the direction of conveyance of the electric overhead conveyor.

(30) In FIG. 9 is represented the orientation of the motor vehicle 18 at a point in time prior to the depositing of the motor vehicle 18 on the assembly platform 16 of the ready-standing conveyor trolley 12. If this orientation of the motor vehicle 18 were maintained, then its longitudinal axis 32, after the entry into the rectilinear production section 14, would be oriented perpendicular to the direction of conveyance 22, which is undesirable.

(31) The electric overhead conveyor therefore comprises in the transfer region a rotating device 48, with which a section of the rail 44 can be rotated, jointly with the overhead trolley 46 suspended therefrom, about a vertical axis. The angle of rotation is fixed such that the motor vehicle 18, following conclusion of the rotation, can be deposited precisely in the desired angular position on the workpiece receptacle 38. Thus, in this illustrative embodiment, the conveyor trolleys 12 do not themselves have to possess rotation units with which the workpiece receptacle 38 can be rotated.

(32) A like rotating device can also be provided in a transfer region at the end of the conveying section 14 if the motor vehicles 18 are there due to be removed again from the conveyor trolleys 12 and transported onward with another conveying device.

(33) FIGS. 11 and 12 show in a schematic top view an initial region of a rectilinear conveying section 14 at two different points in time, according to another illustrative embodiment. No central rotating device is provided there. Instead, the conveyor trolleys 12 possess workpiece receptacles 38, which are respectively rotatable about a vertical axis by motorized or manual means. The end positions of the workpiece receptacles 38 should be lockable in order to prevent unintended rotation.

(34) In the represented illustrative embodiment, the workpiece receptacles 38 are borne, for the purpose of rotatability, respectively by a turntable 50, which is flush-mounted in the assembly platform 16. Due to the rotatability of the workpiece receptacles 38, a motor vehicle 18 fastened thereon can at any time be rotated to the point where it reaches the desired angular position on the respective assembly platform 16, as can be seen in FIG. 12. In the transfer of the motor vehicle 18 from the overhead trolley 46 to the conveyor trolley 12, the motor vehicle 18 is therefore lowered from the overhead trolley 46 in the orientation shown in FIG. 11 and fastened on the workpiece receptacle 38. The workpiece receptacle 38 has been previously transferred into a rotational position in which the longitudinal axis of the workpiece receptacle is oriented parallel to the direction of conveyance 36 of the electric overhead conveyor. After this, the workpiece receptacle is anti-clockwise through 45, whereby the motor vehicle 18 is transferred into the desired angular position.

(35) In a further variant (not represented), not the conveyor trolleys 12, but rather the overhead trolleys 46, are equipped with a rotating device, with which the workpieces 18 can be rotated about a vertical axis.