DE2845913A1 - WORKSTATION FOR A PRODUCTION LINE, IN PARTICULAR FOR AN ASSEMBLY MACHINE - Google Patents

Description

-3- 2846913

The invention relates to a work station for a production line, especially for an Ilontageiamaschine, according to the preamble of claim 1.

Workstations of this type are for workpiece carriers (Pallets) known. Through the fixation of the workpiece carrier lifting of the same from the friction conveyor carried out in the work station there is the advantage that during downtime the workpiece carrier in the workstation through the friction with the friction conveyor rt_r no wear occurs, although the friction conveyor is constantly in Activity is. All those moving with friction come as friction conveyors Means of transport, such as carrying chains, accumulation roller chains or friction roller belts in question. Disadvantage of the known / u'workstations of the kind mentioned is that too high a constructive Effort must be made when the workstation is diverse Requirements should be adaptable and operationally reliable.

For precise alignment of the workpiece carrier in the work station, it is known on the work station and workpiece carrier Provide locating pins and associated bores, which when Fixing stroke of the workpiece carrier are brought into engagement with one another. A secure engagement of the locating pins and holes is not guaranteed without further ado, since the workpiece carrier from the friction conveyor is not in a precisely aligned position are fed to the workstations because the alignment position of the workpiece carriers on the conveyor is relatively imprecise is defined. In order to enable a secure engagement of the pins and holes, one must therefore either the holding means of Work station at which the workpiece carriers start to make very complex, so that the workpiece carriers when starting up in A sufficiently defined position must be brought to bear, or the locating pins must have relatively long inclined contact surfaces provided so that it is possible to find the holes even with a certain positional deviation. It is obvious, that a special design of the holding means the overall system

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expensive and complicated. The special design of the pins is also disadvantageous / because longer dowel pins, one for reasons of stability must have a correspondingly larger cross-section, which is also the Kachteil yields that the fixing stroke is relatively long rough.

The invention is based on the object for a production line of the type in question to create a workstation which, with a simple basic structure, is different Requirements is adaptable and at the same time ensures high operational reliability.

According to the invention, this object is achieved by those mentioned in claim 1 Features solved. The fact that the fixing stroke is subdivided according to the invention and the first stroke stage for the Pre-positioning the workpiece carrier is used, there are a number of surprising advantages. So you can, there at the first Stage of the fixing stroke a prepositioning is carried out, the holding means in the work stations for stopping the workpiece carrier can be designed as a simple controllable blocking means. There are also no precisely machined contact surfaces on the workpiece carriers for interaction required with these blocking agents.

When it comes to workstations where simple operations are carried out, for example assembly work, where the workpiece, and thus the workpiece carrier, does not need to be positioned with very tight tolerances the prepositioning serve as the sole position alignment, i.e. the workpiece carrier can be used after prepositioning with d = r second stroke stage in the one set during prepositioning Position to be clamped to the workstation without dowel pins for fine positioning in the associated Fixing bores would have to be retracted in the second stroke stage.

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When it comes to workstations that require fine positioning of the workpiece pallet is required, i.e. if the prepositioned workpiece pallet is not simply clamped in the workstation is sufficient, but in the second stroke of the fixing stroke dowel pins and holes must be brought into engagement, which on the four-piece carrier and the work station are arranged, the previously performed prepositioning provides the decisive advantage that a safe retraction of the passport is easily guaranteed without the dowel pins or bores having to be provided with extensive inclined surfaces or the like. The final, precise positioning then only requires a very small adjustment of the workpiece carrier, as a result of which the dowel pins can be kept short and are only subject to low stresses.

Another advantage of the invention is that, according to a preferred embodiment, a rotating device for Rotation of the workpiece carrier lifted off the friction conveyor in the first lifting stage is provided by preselected rotation angles can be. This eliminates the need to provide separate turning stations that are connected upstream and downstream of the workstations, as is the case with the known ones Production lines must be available if the workpiece pallet needs to be rotated. It lies It is obvious that when using the workstation according to the invention, this results in a significant saving of space while at the same time significant reduction in investment costs is achieved. In addition, the invention in contrast to the known Production lines can be provided with any angle of rotation of the workpiece carrier for the work process, while in known production lines a rotation is only possible by 180 ° or at most 90 °. This disadvantage of the known Streets stems from the fact that the workpiece carriers turned in the turning stations after turning by means of the friction conveyor into the working

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station must be transported in, but only one transport of the workpiece carriers on the friction conveyor Rotation by 180 °, at most with a rotation of 90 °, is possible. These restrictions do not apply to the invention, since the rotation of the workpiece carrier, regardless of the transport of the same ^ is carried out in the work stations themselves, whereby Rotations by any angle can be performed. The designer of the workstations is therefore responsible for the workpiece carrier and so that the workpiece is available in any rotational position, completely free in the arrangement of the assembly and / or processing units.

With the possibility of the workpiece in the work station in each to be able to rotate any rotational position, there is also the advantage that the workpiece on the workpiece carrier, without having to take any other conditions into account, it can be arranged in such a way that it has the smallest possible frontal area during transport, based on the direction of transport. This makes it possible to use the smallest possible cross-sectional area of the free space, i.e. with the most compact construction of the production line, the largest possible workpieces through the production line to lead through.

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The invention is explained below with reference to drawings in dor single NEN.

Show egg:

Fig. 1 partially broken open and cut

sόν. * ic shown schematically simplified = Front view of one embodiment of a workstation and one in it retracting workpiece carrier;

2 shows a schematically simplified plan view of the workpiece carrier;

3 shows a schematically simplified plan view of the work station according to FIG Fig. 1 without workpiece carrier and

Fig. 4 is a schematic, broken off, partly

cut open and drawn on a larger scale detail from Fig. 1, in which various Working positions of the workpiece carrier are indicated relative to the workstation.

1 shows an exemplary embodiment of a 10 as a whole designated workstation with one located in this Workpiece carrier 11. As can best be seen from FIG. 2, the workpiece carrier 11 has essentially the shape of a square plate, on the top not shown clamping or fixing means for clamping or receiving a also not shown workpiece are arranged and the underside on a friction roller conveyor resting along a desired transport path to the corresponding work stations and moved through them will. When shown

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Example has the roller conveyor frictionally driven Rolls 13 on. Never seen from Fig. 1, the roller conveyor runs 12 above a frame 15 of the work station through this. Strips attached to both sides of the roller conveyor 12 14 prevent the workpiece carriers 11 from sliding down the side of the roller conveyor 12.

In Fig. 1 the workpiece carrier 11 is in its transport position, which is also shown in Fig. 4 with a solid line, directly on the rollers 13 of the roller conveyor on. The friction drive, not shown, of the rollers 13 is constantly in operation during operation, so that on the conveyor 12 on the workpiece carrier 11 continuously acts a feed force in the transport direction. To the workpiece carrier in the To bring the workstation to a standstill, a stop 16 is provided which is connected to a support plate 17 which can be raised by means of a lifting device designated as a whole by 18, in order to move the stop 16 into the path of the transport movement to move the workpiece carrier 11 and bring it to a standstill without the friction roller conveyor 12 is put out of action. In the illustrated embodiment, the lifting device has three lifting cylinders 19, 20 and 21, which, as will be explained in more detail below, can be actuated independently of one another in order to move the support plate 17 to raise in such a way that their vertical movement is gradual. When the lifting cylinder 19 is actuated, the support plate 17 and thus the stop 16 is raised so far that a workpiece carrier 11 entering the work station runs with its stop surface 22 on the stop 16. The support plate 17 is connected to columns 23 for its vertical movement, which are displaceable in a column guide, designated as a whole as 24, which is fastened to the frame 15.

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The working stroke of the lifting cylinder 19 is via its piston rod 25 transferred to the piston rod 26 of the lifting cylinder 20 arranged above, whereby this as well as the one on it attached lifting cylinder 21 are raised, the latter lifting the support plate 17 through its piston rod 27.

In order to work on the workpiece in the workstation 10 by means of the Stop 16 stopped workpiece carrier 11 one operation, For example, to be able to carry out an assembly process or machining process, the workpiece carrier 11 in the workstation can be clamped in a fixed position. This clamping takes place in that the workpiece carrier is lifted from the roller conveyor 12 and so far vertical is moved upwards by pressing together Contact surfaces 29, which are in the corner areas of the workpiece carrier are formed, and arranged stationary on the workstation Contact surfaces 30 for clamping the workpiece carrier 11 comes. The contact surfaces 30 of the workstation are through the The underside is formed by clamping strips 31 which are fastened to brackets 32 which in turn are fastened to the frame 15 of the work station.

The fixing stroke for clamping the workpiece carrier 11 in the Work station 10 is reached by a lifting plate 33 which is connected to the support plate 17 via an intermediate piece 34. The piston rod 27 is fastened to the support plate 17 below the intermediate piece 34. On the top of the lifting plate 33 are a plate 35 extending radially outward beyond the rim of the cup, see in particular FIG. 3, two positioning pins 36 and 37 and two support washers 38 and 39 attached. At the radially outer end, the plate 35 is perpendicular to the top angled to form the abovementioned stop 16. The positioning pins 36 and 37 point in their lower area each have a collar 40 or 41, the height of which, measured from the top of the lifting plate 33, the height of the plate 35 and the support

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washers 38 and 39 corresponds. The tops of the collars 40, 41, the plate 35 and the support washers 38 and 39 form the support surfaces which are attached to the underside of the workpiece carrier 11 in order to lift it up during the fixing stroke for clamping in the workstation. The positioning pins occur 36 and 37 into associated fixing bores 42 and 43 (see FIG. 2) of the workpiece carrier 11.

The fixing stroke of the workpiece carrier stopped by the stop 16 11 takes place

in two lifting stages, of which the first lifting stage is used for prepositioning of the workpiece carrier 11 before clamping the same in serves the workstation. The lift cylinder is used for this lift stage 20 actuated to raise the lifting plate 33 so far that the positioning pins used for the prepositioning process 36 and 37 enter the fixing bores 42 and 43 and the workpiece carrier 11 by applying the support surfaces of the Lifting plate 33 is then lifted off the roller conveyor 12 and out of the transport position shown in solid lines in FIG. 4 is moved up into an intermediate position indicated by dashed lines, in which the contact surfaces are 29 are still at a considerable distance from the stationary contact surfaces 30. Used after prepositioning the second lifting stage is then carried out by additionally actuating the lifting cylinder 21, the workpiece carrier 11 becomes Raised beyond this intermediate position so far that the contact surfaces 29 and 30 are pressed against one another and thus earthed the workpiece carrier 11 is festgekleromt in the work station 10 will. This second stroke stage of the fixing stroke of the workpiece carrier 11 is also indicated in FIG. 4 with dashed lines.

The diameter of the pins 36 and 37 used for prepositioning is somewhat smaller than that of the associated fixing bores 42 and 43. This means that when prepositioning the workpiece carrier 11 not yet in a particularly precisely defined Position is aligned, but initially only a position alignment within a relatively wide tolerance range

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takes place. Due to the comparatively small diameter of the pins 37 and 38 relative to the associated bores there is the advantage that a safe retraction of the pins into the bores is guaranteed, although the workpiece carrier is fed by the roller conveyor 12 in a relatively uncontrolled positional alignment and only a simple one and cheap stop 16 is used to stop the workpiece carrier. If in the workstation in question

Operations are carried out that do not have an extremely precise positioning of the workpiece and thus of the workpiece carrier make necessary, this can easily be done in the positional orientation in which it is located after prepositioning are clamped to the stationary contact surfaces 30 in the second lifting stage. If, however, a very precise orientation of the workpiece carrier 11 is required in the work station 10, is in the second lifting stage before clamping fine positioning carried out. To this end, extend in two diametrically opposed Fine positioning pins 45 and 46 arranged in the corner areas of the workpiece carrier 11 within the area of the contact surfaces 29 up. These fine positioning pins are for engagement provided in fine positioning bores 48 and 49, which are formed in sockets 50, which are in recesses in the terminal strips 31 can be used.

In the second stroke stage of the workpiece carrier 11, the fine positioning pins 45, 46 are moved into the fine positioning bores 48 and 49 with high operational reliability, since the workpiece carrier 11 has been pre-positioned already occupies a fairly well-defined position, so that the pins can be found in the bores without any special Precautions would be required, can be made.

If, as already mentioned, fine positioning of the workpiece carrier 11 is not required in a relevant work station, so that the workpiece carrier 11 in the after prepositioning assumed position can easily be clamped at the workstation, the sockets 50 in

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the clamping strips 31 are omitted, so that the Fsinpositionierstifte 45, 46 extend without fine positioning into the recesses left free by the sockets 50 in the second lifting stage when the workpiece carrier 11 is clamped. The omission of the precisely machined sockets 50 results in a substantial reduction in the manufacturing costs of the work station in question. If the alignment accuracy of all workstations in a production line is sufficient for the respective work step by pre-fixing the workpiece carrier, the positioning pins 48 and 49 can also be omitted.

Since there are four terminal strips 31 at the work stations in the illustrated embodiment, if it is desired that all terminal strips 31 be provided with sockets 50 with Feinpositionierbohrungen so that except for the Fine positioning bores 48 and 49, if necessary, two further fine positioning bores 58, 59 are present, as shown in FIG Fig. 3 is indicated with a dashed line.

The division of the fixing stroke into two stroke stages opens up the particularly advantageous possibility of using the workpiece carrier 11, which has been brought to a standstill in the workstation, to twist in the workstation itself. Separate turning stations are arranged in front of and behind the work stations thereby made superfluous. The workpiece carriers 11 can, regardless of the rotational position in which the operation be carried out in the relevant workstations should, so always in a certain constant transport orientation on the roller conveyor 12 between the work stations 10 are transported so that the workpiece carriers are not provided with buffers 52 on all four sides must, but only on the front side of the transport orientation and the opposite, rear side. The same applies to the stop surface 22 which, although two stop surfaces 22 are shown in the drawing.

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only on the front side in the transport direction on the workpiece carrier 11 needs to be present.

The Ilubteller 33 serves as part of the rotating device for the Rotation of the workpiece carrier 11, which beira exemplary embodiment is designed for angles of rotation up to about 100 °. If larger angles come into consideration, different types are known Drch £ .inrichtunge.n, e.g. cream stick drives, for. mission brought. In the exemplary embodiment, the intermediate piece 34, which is firmly connected to the lifting plate 33, rotatably mounted on the support plate 17. A from the intermediate piece 34 radially extending pivot arm 53 is on a piston rod

54 one at 55 "pivotable on a shoulder 17 'of the support plate 17 mounted pivot cylinder 55 articulated. After prepositioning, when the workpiece carrier 11 from the roller conveyor 12 is lifted and raised into an intermediate position in which (see FIG. 4) no fixation has yet taken place one is made by actuating the swivel cylinder

55 induced rotary movement of the lifting plate 33 on the workpiece carrier 11, with the positioning pins 36, 37 provided for prepositioning acting as drivers.

If at a work station with a rotating device one of 90 or 130 different angles of rotation occur, instead of four terminal strips 31, the contact surfaces 29 of the workpiece carrier 11 are clamped firmly on the outside are provided, only two different Klc-i..nleist3n sain, since with such angles of rotation in the Rtg & l two diametrical opposite corner areas of the workpiece carrier 11 are located within the area of the conveyor belt, which must remain free of device parts. In such a case it may be necessary to not only have two diametrically opposed fine positioning pins on the workpiece carrier 11 45, 46, but for the interaction with those in the relevant workstation arranged terminal strips another pair of diametrically opposed fine positioning pins 56 and

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to be arranged in the other two corner areas within the contact surface 29, as indicated in FIG. 2 with a dashed line, preferably in one to the axis of rotation
U ^ r Ür ~ hbe -. / E young of the workpiece carrier 11 symmetrical positional arrangement, as is preferably also the case with the other fine positioning pins.

In the guiding form shown in the drawing, the clamping strips 31 are arranged along the fine positioning bores in such a way that the VZerkstiickträgers 11 can only be rotated and clamped by 90 or 180 rotational movements
is.

Claims (7)

Claims I 1. ) Work station for a production line, in particular for an assembly machine, with a lifting device for executing a fixing stroke, by means of which a workpiece carrier can be lifted off a friction conveyor, on which it can be fed to the work station until it rests on controllable holding means, and can be fixed in its position is, characterized in that the fixing stroke is divided into two lifting stages, of which the first stage is provided for prepositioning the workpiece carrier (11) lifted off the friction conveyor (12) and the second stage for fixing the same. 2. Workstation according to claim 1, characterized by a rotating device (53 to 55) for rotating the in the first Lifting stage of the workpiece carrier (11) lifted off the friction conveyor (12) by the preselected angle. 3. Work station according to claim 1 or 2, characterized in that for prepositioning on the lifting device (18, 33) and shaped complementary to one another on the workpiece carrier (11) Matching means (3C, 37, 42, 43) are provided, their / ibmesmetr are chosen so that the Vorposittonieruriy with proportionately rough tolerances. 17/0508 relef. '; rji? -fht; Aii.ikinfU 'timl • iiftr i> jv in 1 only η.ι'ίι:;: more ί i ^j .! dd Ji ₁ JIiJ Vf.t'ir li:, ti ORIGINAL INSPECTED 4. Workstation according to one of claims 1 to 3, characterized characterized in that at the work station (10) and on the workpiece carrier (11) mutually complementary fitting means (45, 46, 48, 49) for fine positioning of the Workpiece carriers (11) are provided bsim fixing. 5. /.rbeitsstation according to claim 4, characterized in that in the case of an essentially rectangular shape, the workpiece carriers (11) at least in the area of two diametrically opposite one another Corners of the same each have a fine fixing pin (45, 46) arranged is. 6. Work station according to claims 2 and 5, characterized in that that in the bar area of all four corners of the workpiece carrier (11) each a fine fixing pin (45, 46, 56, 57) is arranged is. 7. Work station according to claim 6, characterized in that as a fitting means for prepositioning on the lifting device (18, 33) and at least two pre-fixing pins on the workpiece carrier (11) (36, 37) and associated pre-fixing bores (42, 43), which are connected to each other in the first stage of the fixing stroke Come into engagement, it is provided that at least the part (33) of the lifting device which interacts with the workpiece carrier (11) (18, 33) is rotatable by means of the rotating device (53 to 55) and that the fitting means provided for the prepositioning (36, 37, 42, 43) also as Mitneiiratr when rotating serve to rotate the workpiece carrier (11). - 3 / Bc-Schrcibuncj