WO2014071433A2 - Conveying facility and method for conveying parts by means of part carriers of a manufacturing plant - Google Patents

Abstract

The invention relates to a conveying facility (2) for conveying parts (3) by means of part carriers (4), comprising: a base frame on which guide rollers (17, 18) are rotatably mounted; a conveyor chain (19) which is guided about the guide rollers (17, 18) and comprises the part carriers (4), said conveyor chain having an upper strand (20) and a lower strand (21); an advance drive (23) for moving the conveyor chain (19) and being coupled to one of the guide rollers (17, 18); and a guide device (22) for the upper strand (20) of the conveyor chain (19) which guide device extends between the guide rollers (17, 18). A first guide roller (17) is coupled with an electronically controlled drive motor as the advance drive (23) and a second guide roller (26) is coupled with a braking drive (24). The invention further relates to a method for the clocked conveyance of parts (3), wherein, in the braking phase, the first guide roller (17) is driven by the electronically controlled drive motor such and a second guide roller (18) is braked by the braking drive (24) such that the forward, upper strand (20) is tightened between the guide rollers (17, 18).

Description

 Transport system and method for the transport of parts by means of parts carrier of a production plant

The invention relates to a transport system and a method for the transport of parts by means of parts carrier within a manufacturing plant with in the transport direction successively arranged workstations and / or parts supply stations.

WO 89/06177 AI and WO 89/08002 AI disclose a generic Transportanla- ge for the transport of parts by means of parts carrier, which a base frame, rotatably mounted on this deflection wheels, a guided around the pulleys transport chain with a leading, upper strand and a returning , Lower strand, a between the guide wheels extending guide device for the leading, upper strand, and comprises a coupled with one of the guide wheels electric feed drive for moving the conveyor chain in the transport direction. The chain links of the transport chain form the part carriers. The transport chain is endless and is set manually in it via a mechanical tensioning device a bias. The prestressing of the transport chain must be checked by trained specialist personnel at regular maintenance intervals.

In addition, the transport system has to be highly dynamic in order to meet the high line requirement to the production plant, therefore switching between acceleration phases and deceleration phases is made within the shortest possible time intervals. This is associated with vibrations in the transport chain, which can lead to insufficient longitudinal positioning of the parts carrier relative to the workstations and / or parts delivery s stations.

The invention has for its object a transport system and a method for conveying parts by means of parts carrier to create within a manufacturing plant, with which (m) can achieve improved positioning of the parts carrier in the transport direction relative to workstations and / or parts supply stations.

The object of the invention is achieved by the measures according to claim 1. The workstations and / or parts delivery s stations are arranged on one or both sides of the transport system in a preferably constant grid spacing. Thus, it is common for workstations to include assembly devices, joining devices and / or machining devices and the like, and the parts supply stations singulation devices, alignment devices and / or conveyors and the like. The workstations each define a spatially limited work area in which a parts carrier is moved in order to assemble, add and / or process parts there. The drive motor is a dynamic electric motor, in particular servomotor, which is intermittently operated by a grid spacing of the work stations and / or parts delivery s stations. The feed path per further cycle of the transport chain corresponds to the grid spacing. The part carriers are accelerated by the feed drive in an acceleration phase in the work areas and after completion of the operations from the work areas out. Before reaching the working positions in the work areas can be provided that the parts carrier are braked by the feed drive and the brake drive in a braking phase again to a standstill. Alternatively, it can be provided that the brake drive is omitted and the transport chain is biased so that only one feed drive is needed, which due to the circulation of the transport chain and the bias simultaneously acts as a brake drive. During the stoppage phase of the parts carrier work processes can be performed simultaneously at several workstations. The standstill phase results from the duration of the longest working process in the row of the workstations.

The drive motor (electric motor) is connected to an electronic control device, which in turn comprises a controller, in particular servo controller (servo amplifier). By regulation (torque, speed or position control) of the drive motor, a high positioning accuracy of the parts carrier is already achieved in the transport direction.

The "regulated" driving force is transmitted from the first deflection wheel via positive engagement on the transport chain and thus even with the high acceleration forces slip-free This is true both for the acceleration phase and for the braking phase of the feed drive.

The positioning accuracy of the parts carrier can also be significantly improved in the transport direction, if at least in the braking phase of the feed drive or the

Transport chain on the second deflecting a braking force acts so that the leading, upper chain strand is stretched between the pulleys. Chain vibrations occurring in the braking phase are considerably reduced or avoided, so that the parts carriers reach the working positions in the working areas in a shorter time and with higher positioning accuracy compared to the known transport systems. The braking force can be transmitted from the second deflection wheel via positive engagement on the transport chain and thus a slip-free deceleration of the transport chain are made possible even at the high (negative) acceleration forces. Alternatively, it can be provided that the braking force is applied by the first deflecting wheel and the second deflecting wheel is designed as a deflection roller with free rotation possibility. By the bias of the transport chain can be achieved in this case that a braking force of the first deflecting wheel is transmitted directly via the second deflecting wheel on the parts carrier located in the upper strand. It is important that, as described in the exemplary embodiments, the transport chain is guided as accurately as possible and without play.

Against this background, it is now possible to use the transport system also on production equipment in which parts of the smallest dimensions and tightest tolerances are processed. It is also advantageous if the feed drive is formed by a direct drive, the drive motor is coupled directly to the first deflection. For example, so-called "torque motors" are used, which allow large accelerations with very precise longitudinal positioning of the component carriers relative to the workstations Regulation easy.

The brake drive may comprise an electrically controllable or electric drive motor, for example a synchronous motor, which is coupled to the second deflection wheel. The use of an electric drive motor allows the design of different control tasks. The drive motor or electric motor can be used exclusively for braking the transport chain in a braking phase or both for driving the transport chain in an acceleration phase and for braking the transport chain in a braking phase. Preferably, the drive motor is a stepper motor whose voltage terminals with an electronic switch, such as a relay, can be short-circuited for a short time to initiate a braking force to the second deflection. The braking of the transport chain from maximum acceleration can be carried out very quickly by a control device (automatically) and, even in the standstill phase, unwanted movement of the transport chain in the transport direction is avoided. The use of an electric drive motor also has the advantage that in the acceleration phase of the feed drive, this drive motor for driving the transport chain can be switched by this briefly applied to the second guide wheel with a driving force. If the brake drive comprises an electronically controllable drive motor (servomotor), the braking force can be regulated depending on the drive force of the feed drive or speed-dependent.

Furthermore, it can be provided that for applying the clamping force, a clamping device is provided which acts directly on one of the deflection wheels. An advantage of such a clamping device is that thereby the necessary bias in the transport chain can be applied to allow a high positioning accuracy of the individual parts carrier. Furthermore, by the application of the clamping force in one of the deflection wheels, the transport chain can be stretched without much effort.

Alternatively, it may be provided for applying the clamping force, a tensioning wheel is provided, which is arranged at the lower strand of the transport chain between the two deflecting wheels. An advantage of such a design is that the deflection wheels can be rigidly mounted.

An exact height and side guidance of the parts carrier in the upper chain strand can be achieved if the guide s device on the base frame at a distance parallel guides and the transport chain on the guides with guide organs supportable Ket- tenentenglieder, wherein on the one hand a first guide and this associated first guide members each form a height guide surface and side guide surface and on the other hand a second guide and this associated second guide members each exclusively a height guide surface. Combined with the above-described effect of improved positioning accuracy of the parts carriers in the transport direction (longitudinal positioning), it is now possible to process parts with the narrowest tolerance limits.

An advantageous embodiment of the invention is also provided if the base frame in a plane parallel to the transport plane extending boundary and in the longitudinal direction of the guides extending stop strips and that the transport chain are provided on some of their hinged chain links on one of the transport plane opposite bottom with stop projections, which are arranged and designed such that the stop projections engage behind the stop bars on the advancing movement of the transport chain along the guide device. As a result, lifting of the guide members of the chain links or part carriers is limited or even avoided by the guides and ensures the guiding function for the chain links or part carriers even in the event of malfunctions of the feed and / or brake drive.

According to an advantageous embodiment, the guides each form a stop strip extending in their longitudinal direction. As a result, a very compact construction is achieved and in addition a rigid construction for the guides is provided.

Furthermore, it may be appropriate that hold-down elements are formed in the stop bar, through which the parts carrier can be pressed by means of spring elements to the guides. The advantage here is that it can be achieved that can be achieved by taking advantage of the prism guide a guide roller and a guide rail that the parts carrier can be positioned with high accuracy in order to achieve a high resistance to discrepancy in the procedures. Furthermore, it can be provided that the base frame lying in a parallel to the transport plane extending boundary plane, and extending in the longitudinal direction of the guides, further stop strips and that at least over part of the length stop projections of the chain links this stop strips on the upper strand of the Overlap transport chain facing side. The advantage here is that thereby the transport chain is fixed in its vertical position, so that the vibrations that occur by a step-by-step movement of the transport chain in this, as far as possible reduced or completely inferred.

It is also of advantage if the chain links which form the parts carriers or on which the parts carriers are fastened are produced by metal injection-molded parts in the metal injection molding process. Such parts can be manufactured particularly cost-effectively within narrow tolerances with low weight, reduced wall thickness and optionally without post-processing.

But it is also advantageous if the chain links, which form the parts carrier or on which the parts carrier are attached, are made by stamping and forming parts. Such parts may be made of sheet metal without forming formed parts and manufactured at low cost, especially in mass production. The consumption of material for the production is low. The sheet material allows almost unlimited designs. It can non-cutting forming processes, in particular methods for cold forming of sheets, such as bending, pressing, embossing and the like., Are used. The deformation of the sheet takes place in an accuracy that can be realized within narrow position and shape tolerances. Machining can usually be omitted.

According to a possible embodiment of the invention, the transport system has an optical detection device connected to a control device, in particular a camera system, by means of which a relative position (actual position) of at least one part carrier in the transport direction and / or transversely to the transport direction can be detected Device having an evaluation unit, from which in a target-actual comparison, a manipulated variable is calculated, and an actuator, which is a working module of at least one working station is acted upon by the manipulated variable, is connected. Thus, it is now possible that wear-related changes in length of the transport chain and / or positioning inaccuracies of the parts carrier possibly occurring after a long production deployment are compensated for by a self-acting, automatic adjustment of a working module to a corrected working coordinate parallel and / or transversely to the transport direction and no effect on the production process Has. It also proves to be advantageous for dynamic reasons if the brake drive also acts as a feed drive in the acceleration phase of the transport chain. Thus, the brake drive can alternately act with a driving force and a braking force on the second steering wheel.

It is also advantageous if, during the braking phase of the transport chain, the feed drive reduces a drive torque and the brake drive changes a braking torque depending on the drive torque of the feed drive s. In other words, a bias in the upper run of the transport chain is set by a torque difference between the drive torque and the brake torque. The braking torque is lower than the drive torque and may vary depending on the speed of the feed drive.

A torque difference between the drive torque and the braking torque for setting a bias in the upper run of the transport chain can also be achieved if in the braking phase of the transport chain of the feed drive reduces a drive torque and the brake drive generates a braking torque by shorting voltage terminals of an electric drive motor. For a better understanding of the invention, this will be explained in more detail with reference to the following figures.

In each case, in a highly schematically simplified representation: FIG. 1 shows a production s with a first embodiment for a transport system for

Carriage of parts by means of parts carrier and in the transport direction successively arranged work stations and parts supply stations in perspective view; Fig. 2 shows the transport system of Figure 1 in side view. Fig. 3 shows the transport system of Figure 1 in plan view. Fig. 4 part carrier of a transport chain for the transport system of FIG. 2;

FIG. 5 shows the conveyor chain cut along the lines V - V in FIG. 3; FIG. 6 shows the time courses for a working process, the driving force on the transport chain and the braking force on the transport chain over two feed strokes;

Fig. 7 shows a second embodiment of a transport system for the transport of parts by means of parts carrier for a production s anläge of FIG. 1;

FIG. 8 part carrier of a transport chain for the transport system according to FIG. 7; FIG.

9 perspective view of a transport chain with drive unit; Fig. 10 side view of a transport chain with drive unit;

11 shows the conveyor chain cut according to the lines XI - XI in Fig. 10;

FIG. 12 shows a further exemplary embodiment of part carrier of a transport chain for the transport system according to FIG. 2

By way of introduction, it should be noted that in the variously described embodiments, identical parts are provided with the same reference numerals or the same component designations, wherein the disclosures contained in the entire description can be applied mutatis mutandis to the same parts with the same reference numerals or component names. Also, the position information selected in the description, such as top, bottom, side, etc. related to the immediately described and illustrated figure and are to be transferred to a new position analogous to the new situation. Fig. 1 shows a manufacturing plant 1, which comprises at least one transport system 2 for the transport of parts 3 by means of parts carriers 4 and along a transport section in the transport direction 5 successively arranged work stations 6 and part delivery stations 7. The transport system 2 comprises a base frame 8 and can be constructed on this on a support housing 9. For this purpose, the support housing 9 forms on its top side remote from the bottom 10 a mounting plane 11 or connecting plane on which the transport system 2 can be supported with the base frame 8 and detachably fastened to the support housing 9 via connecting elements, not shown, for example screws.

On the other hand, the transport system 2 can also be set up directly on the ground 10 by means of the base frame 8. The number of workstations 6 and / or parts delivery stations 7 may vary depending on the complexity of the product being manufactured. Thus, the production s anläge 1 may include only a workstation 6 or a workstation 6 and a parts supply station 7. The work stations 6 and parts provision s stations 7 are preferably operated automatically.

For reasons of better clarity, only two workstations 6 and only two parts delivery stations 7 are shown in FIG. Typically, such manufacturing facilities include 1 to 20 workstations 6 per transport system 2. The workstations 6 and parts delivery s stations 7 are on a specially designed

Frame structure 12 is arranged, wherein independent storage frame modules 13 can also be constructed on the support housing 9. The bearing frame modules 13 are supported on the mounting plane 11 and are fastened via not shown connecting elements, such as screws, releasably secured to the support housing 9.

In addition, the bearing frame modules 13 can be connected to one another via parallel to the transport direction 5 and guided through receiving openings 14 longitudinal bars 15, as indicated in dash-dotted lines. The longitudinal bars 15 are preferably held against rotation in the receiving openings 14.

Thereby, the bearing frame modules 13 can be connected to a self-supporting frame structure 12, which is characterized by its modular structure. Each storage frame module 13 forms a receiving module. As entered in FIG. 1, two of the three illustrated bearing frame modules 13 are each equipped with a working station 6 and / or a parts supply station 7. By contrast, the third storage frame module 13 is not equipped with a work station 6 and / or parts supply station 7 for reasons of better clarity.

The workstations 6 comprise, according to the embodiment shown, a handling device 16 with a gripper with which a part 3 provided at the parts supply station 7 can be taken over and transferred to a part carrier 4.

On the other hand, a workstation 6 may comprise a process module, for example a press device. In this case, a part 3 may already have been transferred to the parts carrier 4 at a workstation 6 preceding in the transport direction 5 and transported to the workstations 6 following in the transport direction 5, where the parts 3 are joined together. A separate parts delivery station 7 can be omitted at this workstation 6.

The parts supply station 7 comprises a feeding device for conveying and / or separating, with which the parts 3 from a (not shown) Schüttgutbehäl- ter or parts store removed, isolated and / or aligned and conveyed into a staging area, from where the parts. 3 For example, by means of handling s device 16 are removed. The parts 3 are formed for example by grafting, discs, pins, contacts, etc. Such parts delivery stations 7 are known for example in EP 0 637 559 AI, EP 1 460 006 AI or DE 44 34 146 AI.

In FIGS. 2 to 5, the transport system 2 and parts carrier 4 are shown in different views.

The transport system 2 comprises the base frame 8, at this rotatably mounted Umlenkrä- 17, 18, a guided around the guide wheels 17, 18 via positive transport chain 19 with a leading, upper strand 20 and a returning, lower strand 21, a between the Deflection wheels 17, 18 extending guide device 22 for the leading, upper strand 20, coupled to the first guide wheel 17 feed drive 23rd for locomotion of the transport chain 19 in the transport direction 5 and a coupled to the second guide wheel 18 brake drive 24th

The base frame 8 comprises deflection station 25, 26 for the transport chain 19 and between these a plurality of housing parts 27. These housing parts 27 have mutually facing end plates 28 which can be connected to each other via (not shown) guiding and / or coupling devices to the self-supporting support structure. The base frame 8 of the transport system 2 formed by the deflection stations 25, 26 and housing parts 27 is supported on the mounting plane 11 by support devices 29. The housing parts 27 are preferably made in one piece. The support devices 29 are fastened via not shown connecting elements, such as screws, detachably on opposite side walls of the housing parts 27.

The deflecting stations 25, 26 each comprise a housing part, a deflecting wheel 17, 18 rotatably mounted thereon and guide rail parts (not shown), the latter being described in detail in WO 89/06177 A1. As a result, the different chain speeds caused by the polygon effect in the deflection region of the transport chain 19 are also compensated. This allows a dynamic operation of the Tran sports facility 2. The transport chain 19 can be driven at very high feed speeds, which is also possible by the special construction of the transport system 2.

The guide wheels 17, 18 each comprise guide pulleys 30 rigidly connected to each other and diametrically opposed engagement grooves recessed in the outer periphery 31. As will be described below, the parts carriers 4 comprise guide rollers on their longitudinal sides extending in the transport direction 5, which engage in the engagement grooves 31 the deflection plates 30 engage positively, when the transport chain 19 is guided in the deflection around the guide wheels 17, 18.

The transport chain 19 comprises articulated link chains 32 interconnected via chain links, which form the part carrier 4 according to the embodiment shown. In the following, reference is made to a first type of part carrier 4.1 and a second type of part carrier 4.2. The hinge axis 32 connects two successive parts carrier 4.1, 4.2 and extends parallel to the axis of rotation of the guide wheels 17, 18th As can be seen in FIG. 4, the chain links or the respective successive parts carriers 4.1, 4.2 are designed differently and preferably with optimized weight. For example, the parts carrier 4.1, 4.2 metal injection molded parts, which can be produced in high quantities cost and with high manufacturing accuracy.

Both a first type part carrier 4.1 and a second type part carrier 4.2 comprise a receiving plate 33 and on its underside tabs 34, 35. The receiving plate 33 may comprise on its upper side a holding receptacle, not shown, by means of which to be mounted de 3 on the transport between the work stations 6 can be kept. Further, the receiving plate 33 for reasons of weight saving and / or the accessibility of tools of a workstation 6 with a recess 36 are designed.

According to the embodiment shown, the transport chain 19 in the upper strand 20 forms a transport plane 37 (FIG. 5), which is defined by the upper side of the receiving plates 33. The transport plane 37 can also define a work plane at the same time.

As can be seen, extend in the first type part carrier 4.1, the inner (lamellar) tabs 34.1 in the longitudinal direction of the parts carrier 4.1 and protrude with their ends to the opposite direction in the transport direction 5 end edges 38 and each comprise in their opposite end portions bearing bores 39. Die Bearing holes 39 form cylindrical bores through which a bearing pin 40 (FIG. 5) is passed. A longitudinal axis of the bearing pins 40 runs parallel to the axis of rotation of the deflection wheels 17, 18. The outer (lamellar) tabs 35.1 extend in the longitudinal direction of the parts carrier 4.1 and with their ends approximately up to the end edges 38 which are opposite one another in the transport direction 5. In addition, the parts carrier 4.1 can be provided on the bottom with stop projections 41 which are arranged and designed such that they engage behind on the advancing movement of the transport chain 19 along the guide device 22 stop strips 42, as shown in Fig. 5. The stop strips 42 are fixedly arranged on the base frame 8 and extend at a mutual distance in the transport direction 5 between the guide wheels 17, 18th As can be seen, extend in the second type part carrier 4.2, the inner (lamellar) tabs 34.2 in the longitudinal direction of the parts support 4.2 and project with their ends to the opposite direction in the transport direction 5 end edges 38 and each form a bearing receptacle 43 in their end regions forms a cylindrical bore, in which a bearing 44 (Fig. 5) arranged, in particular is pressed. A longitudinal axis of the bore extends parallel to the axis of rotation of the guide wheels 17, 18. The outer (lamellar) tabs 35.2 extend in the longitudinal direction of the parts carrier 4.2 and with their ends approximately up to the opposite in the transport direction 5 end edges 38th

As can be seen in the synopsis of FIGS. 4 and 5, the parts carriers 4 are supported by guide elements, in particular guide rollers 45, 46, on guideways 49, 50, the latter being formed on guides 47, 48. The guide s device 22 includes the guides 47, 48. The guides 47, 48 are fixedly arranged on the base frame 8 and run at a mutual distance in the transport direction 5 between the guide wheels 17, 18th

The first guide 47 forms a vertical and lateral guide track 49, which is formed according to the embodiment shown by inclined to each other tapered guide surfaces. The second guide 48 forms exclusively a height guide track 50, which is formed by the embodiment shown by a parallel to the transport plane 37 extending (horizontal) guide surface.

As can be seen in FIG. 5, the guides 47, 48 can also be produced with the stop strips 42. The stop strips 42 can be integrally formed with the guides 47, 48, or are made separately and secured by fasteners, such as screws on the guides 47, 48.

The guide rollers 45, 46 are each mounted on the bearing pin 40, the latter defining the bearing axis 32.

The first guide roller 45 forms a coaxial with the bearing axis 32 extending engagement portion 51 and a coaxial with the bearing axis 32 extending guide portion 52. Of the Engaging portion 51 is designed with a cylindrical engagement surface. The guide section 52 comprises a circumferential guide groove with a height and side guide surface 53, which is designed to be complementary to the height and side guide track 49 of the first guide 47. The height and side guide surface 53 is formed by shown embodiment by inclined to each other guide surfaces. The first guide roller 45 lies with its guide portion 52 unrolled on the height and side guide track 49 of the first guide 47.

The height and side guideway 49 is tapered in the direction of the guide roller 45, or in the direction away from the guide for the lower strand 21 of the conveyor chain 19 direction. This so formed prism guide causes, in conjunction with the circumferential guide groove of the height and side guide surface 53 in the guide roller 45, a clear high-precision positioning in the direction transverse to the transport direction 5 of the transport chain 19. This positioning is achieved in that due to gravity, the leadership 45 is pressed onto the guide 47 and by the V-shaped configuration of the guide roller 45, and the associated guide 47, the guide roller 45 is centered. The position of the guide roller 45 is thus clearly defined in the vertical and in the horizontal direction. The second guide roller 46 forms a coaxial with the bearing axis 32 extending guide portion 54 with a cylindrical height guide surface 55 and is preferably a rolling bearing. The second guide roller 45 rests with its height guide surface 55 unrolled on the height guide track 50 of the second guide 48. Characterized in that the first guide roller 45 defines the position in the horizontal direction and therefore equivalent to a fixed bearing seen, the second guide roller 46 can be displaced in the horizontal direction relative to the second guide 48 and thus be considered equivalent to a floating bearing.

If the transport chain 19 is guided with the part carriers 4.1, 4.2 around the deflection wheels 17, 18, then the first guide rollers 45 each engage with their engagement section 51 and the second guide rollers 46 each with their guide section 54 into the engagement grooves 31 arranged on a rotation axis Deflection pulleys 30 a form-fitting. The described guide arrangement between the parts carriers 4.1, 4.2 and the guides 47, 48 an exact height and side guidance of the upper strand 20 of the transport chain 19 is achieved. Thus, a working process can also be performed directly on the parts carrier 4.1, 4.2, without having to lift a part 3 of the parts carrier 4.1, 4.2.

As can also be seen in Fig. 5, the bearing pin 40 of the articulated connection of the parts carrier 4.1, 4.2, for which purpose this is passed through the bearing holes 39 of the inner (lamellar) tabs 34.1 of the parts carrier 4.1 and on the other hand by the bearing 44 of the parts carrier 4.2. Between the bearings 44, a spacer sleeve is arranged on the bearing journal 40.

The outer (lamellar) tabs 35.1, 35.2 of the part carriers 4.1, 4.2 are provided at their ends facing away from each other, each with a semicircular recess 56 (Fig. 4). Disc-shaped covers 77 (FIG. 5) are fastened to the front ends of the bearing journal 40, which rests within two recesses 56.

The guide rollers 45, 46 are each arranged in a receiving channel between an inner (lamellar) tabs 34.1 of the parts carrier 4.1 and an outer (lamellar) tab 34.2 of the parts carrier 4.2. As a result, an optimal protection for the guide rollers 45, 46 against external influences, such as splashing water, sweat splashes, dirt deposits is created during a working process.

If a distance dimension 57 between the outer tabs 35.1, 35.2 of the parts carrier 4.1, 4.2 greater than a Führungsbreitenmaß 58 between the guides 47, 48, during a working process and an optimal protection for the guides 47, 48 against external influences, such Splashing, sweat spatter, dirt deposits, chips and the like created.

As not further shown, the lower strand 21 of the conveyor chain 19 between the pulleys 17, 18 are performed, the accuracy of this guide device does not have to meet the accuracy requirements of the guide s device 22, but can. As can be seen from FIGS. 4 and 5, the part carrier 4.1, 4.2 is provided along its end edges 38 with recesses 59 which serve to receive a strip-like sealing lip 60. The sealing lip 60 is fastened to one of the part carriers 4.1, 4.2 at the bottom of the recess 59 and protrudes at the end edge 38 into the recess 59 of the other (in the transport direction 5 subsequent) parts carrier 4.1, 4.2, so that at least one gap gap 61 between facing each other end edges 38 successive parts carrier 4.1, 4.2 is covered. The sealing lip 60 is preferably made of elastic plastic material. If the parts carriers 4.1, 4.2 are guided around the deflecting wheels 17, 18, then the sealing lip section projecting into the recess 59 of the other (in the transporting direction 5) parts carrier 4.1, 4.2 is swung out of the recess 59. It proves to be an advantage if the

Sealing lip 60 is attached to the bottom of the recess 59, which is viewed in the transport direction 5, rear end edge 38 adjacent. As a result, before the arrival of a parts carrier 4.1, 4.2 in the direction of transport 5 considered, first work station 6 between the led out of the deflection 26 parts carriers 4.1, 4.2 of the Stirnkan- te 38 considered in the transport direction 5, front parts support 4.1, 4.2 protruding sealing lip portion into the recess 59 of the viewed in the transport direction, the rear part support 4.1, 4.2 pivoted and achieved the "sealing effect".

As described above, the feed drive 23 are coupled to the first guide wheel 17 and the brake drive 24 to the second guide wheel 18. According to a preferred embodiment, both drives are formed by an electric motor, wherein at least the feed drive 23 comprises an electronically controlled electric motor.

The electric motor (servomotor) of the feed drive 23 is arranged coaxially with the first deflection wheel 17 and is preferably a so-called "torque motor." This is a high-voltage, direct electrical drive from the group of low-speed machines and is characterized by very high torques at relatively low speeds. The voltage supply is possible with DC voltage or AC voltage.The large drive torque of "torque motors" enables large accelerations with very accurate longitudinal positioning of the parts carrier 2 relative to the working stations 6.

As entered in FIG. 3, the electric motor of the feed drive is connected to an electronic control device 62. The control device 62 is provided with a (not shown) electronic control circuit connected, which is impressed by a (not shown) controller a desired trajectory for a desired speed or target drive force. The electric motor of the brake drive 24 is arranged coaxially with the second deflection wheel 18 and is preferably a so-called "stepping motor".

As indicated in FIGS. 3 and 3a, the electric motor of the brake drive 24 is operated by an electronic control device 62. The control device 62 is connected to a schematically represented electronic control circuit 63, which in turn comprises an electronic switch 64, for example a relay, which can short circuit the voltage connections 65 (motor terminals) of the electric motor for a braking phase of the transport chain 19. The electronic switch 64 is for this purpose connected via an indicated control line to the control device 62, which in turn acts on the switch 64 in the braking phase with a brake signal. The switch 64 is thus automatically operated. The voltage terminals 65 are connected to an inverter or frequency converter (not shown), the latter supplying the electric motor with DC voltage or AC voltage. According to another embodiment, the electric motor of the brake drive 24 may include an electronically controlled electric motor (servo motor) which is connected to the electronic control device 62. The control device 62 is connected to an (not shown) electronic drive circuit, which is impressed by a (not shown) controller a desired trajectory for a desired speed or target braking force.

In addition, it is possible, but not shown, that the feed drive 23 comprises two electronically controlled electric motors, which are each arranged coaxially with the first guide wheel 17 and coupled thereto. Both electric motors are electronically controlled electric motors, which are controlled synchronously by the control device 62. The electric motors are preferably so-called "torque motors".

Likewise, the brake drive 24 may include two electric motors, as is not shown. The electric motors are each arranged coaxially with the second deflection wheel 18. net and coupled with this. The electric motors are preferably so-called "stepper motors." Also, both electric motors can be controlled electronically.

As shown schematically in FIGS. 1 and 3, the transport system 2 can also have an optical detection device 66, in particular a camera system. This is connected to the electronic control device 62, which in turn comprises an evaluation unit 67. The evaluation unit 67 can perform a desired-actual comparison for a position of the parts carrier 4. In this way, a relative position or actual position of at least one chain link or part carrier 4 in the transport direction 5 and / or transversely to the transport direction 5 can be detected. The detection of the actual position in the transport direction 5 and / or transversely to the transport direction 5 is preferably carried out at a standstill of the transport chain 19 and a part carrier 4 in the upper strand 20. The evaluation unit 67 can perform a target-actual comparison for a position of the parts carrier 4 and a Calculate the manipulated variable for an actuator 68. The workstation 6 comprises the actuator 68, in particular at least one electronically controlled actuator, such as linear drive, by means of which a Nachpositionierung a working module, in particular peripheral device, such as gripper, in a corrected working coordinate parallel to the transport direction 5 and / or transversely to the transport direction 5 can be performed. For this purpose, when the deviation of the actual position from the target position occurs, the actuator 68 is provided with an electrical correction signal or a corrected manipulated variable and, accordingly, the working module (peripheral device) is moved by the actuator 68 into the corrected working coordinate.

If the production unit 1 comprises a plurality of workstations 6, each having one actuator 68, a postpositioning of the work modules, in particular peripherals, for example gripper, joining device and the like, can take place in each of the work stations 6, in each case a corrected working coordinate parallel to the transport direction 5 and / or transversely to the transport direction 5 are performed.

The evaluation of the desired-actual position of at least one parts carrier 4 can be carried out at defined time intervals or after each power stroke when the transport chain 19 is at a standstill. 6a to 6c show the course of a working process, the course of the driving force (drive torque) for the feed drive and the course of the braking force (braking torque) for the brake drive over two feed cycles of the transport chain. The working process (FIG. 6 a) is, for example, a welding process in which parts 3 are positioned and joined to one another. During the duration of the work process, the transport chain 19 is stationary. If several work stations 6 are present, then the standstill phase results from the duration of the longest work process in the row of workstations 6. The feed cycle for the transport chain 19 consists of an acceleration phase II,

I ₂ , ... I _n and a braking phase Iii, Π ₂ , ■■ · Π _η together. Between the braking phase Iii, II ₂ , ■ II · II _{n of} a preceding feed clock and the acceleration phase Ii, I ₂ ,... I _{n of} a subsequent feed clock is a still stance phase Uli, .. III _n , as in Fig. 6b, 6c can be seen.

During the standstill phase, no driving force (drive torque) and braking force (braking torque) act. Basically, it is conceivable, as registered in dashed lines, that in the stoppage phase of the transport chain 19 from the electric motor of the feed drive 23, a driving force on the first guide wheel 17 and the electric motor of the brake drive 24, a braking force on the second guide wheel 18 act such that on the throughout the duration of the standstill phase constant bias conditions in the upper run 20 of the transport chain 19 prevail. The driving force and braking force are - depending on the friction conditions - in terms of magnitude approximately equal. However, such an operation is only required if positioning of the parts carrier 4 relative to the workstations 6 in the range of a few hundredths of a millimeter is required.

Usually, however, it is sufficient for the positioning of the parts carrier 4 relative to the workstations 6 in the range of a few tenths of a millimeter, when the bias in the upper run 20 of the conveyor chain 19 is adjusted solely by the friction conditions in the system.

As can be seen from FIG. 6b, within a feed cycle the electric motor of the feed drive 23 is connected between the acceleration phase Ii, I ₂ ,... I _n and the braking phase Iii, II ₂ , ... II _n switched. During the acceleration phase Ii, I ₂ ,... I _n , a drive force (drive torque) as desired value or SoU trajectory "Fs ₀ u" (M _so u) is predetermined by the controller such that a steep (positive) acceleration increase within a short period of time to .. ti takes place which is followed by a relatively longer period of time ti .. t ₂ constant acceleration. Then a transition from the acceleration phase includes Ii, I _2, ... I _n the

Braking phase Iii, Π ₂ , ■■ · Π _η , which results from a steep acceleration drop within a short time t ₂ .. t ₃ .

After the time t ₃ , the driving force (drive torque) reverses the sign and initiates the braking phase Iii, H ₂ , ... II _n .

During the braking phase Iii, II ₂ , ■■ · Πη a driving force (drive torque) is specified by the controller as a setpoint or SoUtrajektorie that the steep acceleration drop continues within a short time t ₃ .. t ₄ , which a relatively longer Time span t ₄ .. ts constant (negative) acceleration follows. Thereafter, a steep (negative) acceleration increase within a short period ts .. t ₆ follows.

According to the embodiment shown, the time span to .. ti and time span t ₂ .. t _{3 are} approximately the same length. This is possible because a negative drive force or braking force (braking torque) from the brake drive 24 also acts in the braking phase Iii, Π ₂ , ■■ · Π _η . On the other hand, the time span t ₂ .. t _{4 can} also amount to a multiple of the time span to .. t ₂ , in order to achieve the most gentle braking possible for the transport chain 19.

As is apparent from Fig. 6c, within a feed cycle of the electric motor of the brake drive 24 between the acceleration phase Ii, I ₂ , ... I _n and the braking phase Iii, II ₂ , ... II _n connected.

On the other hand, it is also possible that the brake drive 24 is operated exclusively with a braking phase Iii, H ₂ ,... II _n , which at the latest with the end of the acceleration phase Ii, I ₂ ,... I _{n of} the feed drive 23, therefore starts at the end of the time period t ₂ .. t ₃ . However, the braking phase Iii, Π _2, ■■ · _Π η of the brake actuator 24 to be started already at the end of the time period ti .. t _second Accordingly, in the acceleration phase Ii, I ₂ ,... I _n, a drive force is generated only by the feed drive 23. However, it proves to be advantageous if, during the acceleration phase II, I ₂ ,... I _{n of} the feed drive 23, the brake drive 24 also acts as an "active" drive, as shown in FIG. 6c.

During the acceleration phase Ii, I _2, ... I _n is _"0 u Fs" _(so u) defined by the controller in such a drive force (drive torque) as a setpoint or SoUtrajektorie that a steeper (more positive) to increase in acceleration within a short period of time .. ti, which follows a relatively longer period ti .. t _{2 of} constant acceleration, after which a transition from the acceleration phase Ii, I ₂ ,... I _{n to} the braking phase Iii,

II ₂ ,... II _n , which results from a steep drop in acceleration within a short time span t ₂ .. t ₃ .

After the time t ₃ , the driving force (drive torque) reverses the sign and initiates the braking phase Iii, II ₂ , ··· Π _η .

During the braking phase Iii, H ₂ ,... II _n , a drive force (drive torque) is specified by the controller as desired value or SoU trajectory in such a way that the steep acceleration decrease continues within a short time period t ₃ ... T ₄ , which is a relative one longer time interval t ₄ .. ts constant (negative) acceleration follows. Thereafter, a steep (negative) acceleration increase within a short period ts .. t ₆ follows.

As illustrated in FIGS. 6 b, 6 c, the setpoint value for the drive force (drive torque) at the brake drive 24 may be lower than the setpoint value for the drive force (drive torque) at the feed drive 24.

In Figs. 7 and 8, a second embodiment for the transport system 2 'and the parts carrier 4' is shown. The transport system 2 'comprises the base frame 8', at this rotatably mounted (not visible) deflecting wheels 17, 18, a guided around the guide wheels 17, 18 via positive transport chain 19 'with a leading, upper strand 20 and a returning, lower strand 21st , a guide device extending between the guide wheels 17, 18. tion 22 'for the leading, upper strand 20, one coupled to the first guide wheel 17 feed drive 23 for locomotion of the transport chain 19' in the transport direction 5 and coupled to the second guide wheel 18 brake drive 24. The base frame 8 'includes deflection stations 25, 26th for the transport chain 19 'and between these several housing parts 27'.

As can be seen from these figures, the chain links or part carriers 4 'are formed by stamped and formed parts. Likewise, the housing parts of the deflection stations 25, 26 and / or housing parts 27 'of the base frame 8' can be produced as stamped and formed parts.

FIG. 8 shows a longitudinal section of the transport chain 19 ', which comprises articulated links connected by joint axes 32'. On the chain links (not shown) supporting plates can be attached, the latter form the part carrier 4 '. The transport chain 19 forms in the upper strand 20 a transport plane 37 ', which is defined in this case by the top of the support plates and is above the strand 20. The transport plane 37 'can also define a work plane at the same time.

The chain links comprise a receiving plate 69 and on its underside parallel to the transport direction 5 extending tabs 70. The receiving plate 69 may have on its upper side the support plate with a holding receptacle, not shown, which can hold parts to be mounted 3 on the transport between the workstations 6.

The lugs 70 protrude with their ends to the opposite in the transport direction 5 end edges of the receiving plate 69 and each comprise in their opposite end portions bearing bores 71. The bearing bores 71 form cylindrical holes, through each of which the bearing axis 32 'bildender Bearing journals are passed. A longitudinal axis of the bearing pin extends parallel to the axis of rotation of the guide wheels 17, 18. At the ends of the bearing pins guide elements, in particular guide rollers 72 are arranged. In addition, the parts carrier 4 'is provided with guide members, in particular guide rollers 73, which are rotatable about axes of rotation aligned perpendicular to the plate plane. The parts carrier 4 'are based on the guide members, in particular guide rollers 72, 73 on guideways 74, 75, the latter are formed on guides 76. The guide device 22 'comprises the two guides 76 which are fixedly arranged on the base frame 8' and extend at a mutual distance in the transport direction 5 between the guide wheels 17, 18.

The guides 76 each form separately arranged height and side guideway 74, 75, which is formed by the embodiment shown by at right angles to each other and in the transport direction 5 extending guide surfaces. The guide roller 72 forms a coaxial with the bearing axis 32 'extending guide portion with a cylindrical height guide surface and is preferably a rolling bearing. If the transport chain 19 'with the parts carriers 4' is guided around the deflection wheels 17, 18, then the guide rollers 72 engage in a form-fitting manner in the above-described engagement grooves 31 of the deflection disks 30 arranged on a rotation axis.

The described guide arrangement between the parts carriers 4 'and the guides 76 an exact height and lateral guidance of the upper strand 20 of the transport chain 19' is achieved. Thus, a work process can also be performed directly on the parts carrier 4 'without having to lift a part 3 from the part carrier 4'.

Although according to the preferred embodiment, an electric motor is used as a brake drive, it would also be conceivable that the brake drive comprises a so-called "rotation brake", as it has become known, for example from DE 20 2006 010 648 Ul.On the other hand, it would also be conceivable that the brake drive 24 comprises a braking device with brake elements engageable with each other, in particular a so-called "magnetic brake", as it has become known, for example from DE 197 52 543 AI. In this case, a brake disk (first brake element) is non-rotatably mounted on the (m) to be braked or fixed deflecting pulley 30 or deflecting wheel 18. On the other hand, the brake drive 24 comprises an actuator via an axial between a braking position and a

Release division sliding armature disc with a fixed brake pad (second brake element). The actuator is connected to the control device 62, which in turn the armature disk in the braking phase Iii, H ₂ , ... II _n of the release pitch in the brake position controls. In the braking position, the armature disk is pressed with its brake pad against the brake disc, so that the transport chain 19; 19 'can be braked and / or determined on its advancing movement by the frictional engagement between the brake pad on the armature disk and the brake disk.

Also, an electromagnetic brake with a permanent magnet as a brake drive 24 is possible, as it has become known for example from DE 10 2005 006 699 AI.

Thus, the invention is not limited to consider that the brake drive 24 includes an electrically controllable, optionally controllable electric motor, but may also include a braking device which acts permanently in both the acceleration phase and braking phase of the feed drive 23, therefore, the second guide wheel 18 continuously with a braking force (braking torque) acted upon. In this case, although a more powerful drive motor on the feed drive 23 is necessary, however, a control of the brake drive 24 can be omitted.

FIGS. 9 to 12 show a further embodiment of the transport system 2, which may be independent of itself, wherein the same reference numerals or component designations are again used for the same or constructively only slightly modified parts as in the preceding figures. To avoid unnecessary repetition, reference is made to the detailed description in the preceding figures.

Above all, the individual embodiments shown in FIGS. 9 to 12 can form the subject of independent solutions according to the invention. The relevant objects and solutions according to the invention can be found in the detailed description of these figures.

The embodiment of the transport system 2 shown in FIGS. 9 to 12 differs in some points from the exemplary variants illustrated in the preceding figures. Due to individual constructive differences, it is also possible to reshape the operation of such a transport device something, or to simplify this. Thus, a variant embodiment as shown in FIGS. 9 to 12 can be operated as follows. In order to be able to move the transport chain 19 in the transport direction 5, a first deflecting wheel 17 is set in motion by means of a feed drive 23 coupled to the first deflecting wheel 17 in this embodiment. The deflection for the return of the transport chain 19 is accomplished by a second guide wheel 18, which is mounted on the opposite side of the transport system 2. In contrast to the first embodiment described, however, this second deflection wheel 18 does not necessarily have to be equipped with a brake drive 24, but rather it is also possible that it can rotate freely.

In order to allow an exact positioning of the individual parts carrier 4, of course, as in the first embodiment, a possibility must be provided to tension the transport chain 19, in particular the upper strand 20 to train. In this embodiment, the transport chain 19 is held by a fixed predetermined bias to train.

Due to the bias can be achieved that tolerances in the bearings of the individual chain links of the transport chain 19, or tolerances at the bearings of the guide wheels 17, 18 are compensated to increase the positioning accuracy of the individual parts carrier 4. Thus, it is also ensured in the transport direction 5 that the individual parts carriers 4 are positioned as accurately as possible.

This bias voltage can be achieved by biasing one of the deflection wheels 17 or 18 by means of a tensioning device 78 after installation of the transport chain 19. For this purpose, for fastening one of the deflecting wheels 17 or 18 on one of the deflecting stations 25 or 26, a slot guide 79 may be provided so that this deflecting wheel 17 or 18 can be displaced in the transport direction 5, whereby the transport chain 19 can be prestressed. For this purpose, the tensioning device 78 can be designed, for example, as an adjusting screw with a force indicator. Furthermore, it is also conceivable that the tensioning device 78 is designed as a spring assembly. The necessary biasing force to enable an advantageous operation is dependent on the mass, as well as on the length of the transport chain 19th After installation and tensioning of the guide wheels 17 or 18 can be provided that they are secured against displacement in the transport direction 5. This is achieved in that they are secured relative to the respective deflection station 25 or 26 with a fastening means 80, which may be mounted in the slot guide 79. Especially with very dynamic movements of the transport chain 19, it may be useful if the deflection wheels 17 or 18 are fixed, since it could lead due to the inertia of the transport chain 19 during operation, for example, that an inserted spring assembly for tensioning the guide wheels 17 or 18, is further deformed. If the deflecting wheels 17 or 18 are fixed, then it seems to be expedient if this fixing is loosened at regular time intervals, in order to be able to compensate, for example, any subsidence in the transport chain 19 and to prestress the transport chain 19 again with the original value. For this purpose, it can also be provided that the clamping device for fixing the deflection wheels 17 or 18 is automatically controlled. Furthermore, it is also conceivable that both guide wheels 17 and 18 are arranged by means of slot guide 79 slidably to the deflection stations 25 and 26 in order to allow adjustment for free positioning of the guide wheels 17 and 18 can.

As an alternative to the bias of the transport chain 19 via one of the two deflection wheels 17 or 18 can be provided that a tensioning wheel 81 is used, which at the bottom

Strand 21 of the transport chain 19 attacks. As with a voltage of the pulleys 17 or 18, such a tensioning wheel 81 can be biased by various mechanisms and possibly also fixed or automatically re-tensioned. The apparent in the embodiment in Fig. 12 transport chain 19 comprises articulated axles 32 hingedly interconnected chain links, which are formed as part carrier 4. In contrast to the first embodiment, only one type part carrier 4 is used here, whereby the chain structure is simplified. The articulation axis 32 respectively connects two consecutive parts carriers 4 and runs parallel to the axis of rotation of the deflecting wheels 17, 18.

All features and advantageous features of the transport chain 19, which are not separately described or decidedly excluded in this embodiment, corresponding the description of the transport chain 19 according to the embodiment in Figures 1 to 3, wherein it should be noted that in the first embodiment of the transport chain 19 described parts carrier 4.1 and 4.2, referred to in this embodiment as parts carrier 4. Also, the tabs 34.1 and 34.2 and 35.1 and 35.2 are referred to as tabs 34 and tabs 35 due to the uniform structure of the transport chain 19 in this embodiment.

All references which refer to the description of the transport chain 19 in FIGS. 4 and 5 are referred to FIGS. 12 and 11 in this exemplary embodiment.

As can be seen, in the part carrier 4, the inner, preferably lamellar, tabs 34 extend in the longitudinal direction of the parts carrier 4 and protrude with their ends on an end edge 38 facing away in the transport direction 5 and have bearing bores 39 in the end region of this end edge 38. In this case, the tabs 34 are in each case identical and of opposite configuration so as to be able to be used in one side each of the parts carrier 4, wherein the bearing bores 39 can be formed with different diameters. The bearing bores 39 form cylindrical bores through which a bearing journal 40 (FIG. 11) is passed. In one of the transport direction 4 facing front edge 38, the tabs 34 each form a bearing receptacle 43 in their end regions. The bearing receptacle 43 forms a cylindrical bore, in which a bearing 44 - Fig. 11 - arranged, in particular pressed.

A longitudinal axis of the bearing pin 40 extends parallel to the axis of rotation of the guide wheels 17, 18. The outer tabs 35 extend in the longitudinal direction of the parts carrier 4 and with their ends approximately to the opposite direction in the transport direction 5 end edges 38. In addition, the parts carrier 4 on the Bottom are provided with stop projections 41, which are arranged and designed such that during the advancing movement of the upper strand of the transport chain 19 along the guide device 22 - as shown in Fig. 11 - they reach behind the stop strips 42. The stop projections 41 can hereby be designed as simple bent parts, which engage behind the stop strips 42, whereby due to the relative displacement between the parts carrier 4 and stop strips 42, these slide on one another. Furthermore, the stop projections 41 can be made with freely rotatable roller elements, whereby the wear of the roller bearings minimizes wear. can be miert. The stop strips 42 are fixedly arranged on the base frame 8 and extend at a mutual distance in the transport direction 5 between the guide wheels 17, 18. Furthermore, it can be provided that in the stop strips 42 hold-down elements 82 are provided, which are biased by a spring element 83 and are arranged in that the stop projections 41 are loaded with a predefined force, whereby the part carriers 4 are pressed onto the guides 47 and 48 by means of the guide rollers 45 and 46. It can thereby be achieved that the parts carriers 4 are always in the same working position as possible, as a result of which the reproducibility can be increased.

The height and side guideway 49 is tapered in the direction of the guide roller 45, or in the direction away from the guide for the lower strand 21 of the conveyor chain 19 direction. This thus formed prism guide, in conjunction with the circumferential guide groove of the height and side guide surface 53 in the guide roller 45, a unique high-precision positioning in the direction transverse to the transport direction 5 of the transport chain 19. This positioning is achieved by the fact that due to gravity the guide roller 45 is pressed onto the guide 47 and is centered by the V-shaped configuration of the guide roller 45, or the associated guide 47, the guide roller 45. The position of the guide roller 45 is thus clearly defined in the vertical and in the horizontal direction.

By means of the hold-down elements 82, this centering, which is achieved by gravity, can be further improved or increased, whereby the positioning accuracy of the individual parts carriers 4 can be further increased.

In a preferred embodiment, such a hold-down element 82 is provided at each working position, which is biased by a spring. It can thereby be achieved that each part carrier 4 located in the working position can be positioned as accurately as possible. In a further embodiment it can be provided that a hold-down element 82 is used, which extends over the entire length of the stop strips 42, whereby not only in the respective working position a pressing of the parts carrier 4 to the guides 47 and 48 can be achieved. As can be seen in the synopsis of FIGS. 11 and 12, the parts carriers 4 are supported by guide elements, in particular guide rollers 45, 46, on guideways 49, 50, the latter being formed on guides 47, 48. The guide rollers 45, 46 may in this case comprise a bearing, through which the guide rollers 45, 46 are received rotatably relative to the bearing pin 40 at this. Furthermore, it can also be provided that the bearing journal 40 is designed such that at least one guide roller 45 or 46 together with the bearing of the guide roller is an integral part of the bearing journal 40. If the transport chain 19 with the parts carriers 4 is guided around the deflection wheels 17, 18, then the first guide rollers 45 each engage with their engagement section 51 and the second guide rollers 46 with their guide section 54 in the engagement grooves 31 of the deflection pulleys 30 arranged on a rotation axis , In addition, it can be provided that a further bearing element 84 is provided, which can engage positively in the deflection pulleys 30.

In the embodiment of the transport chain 19, which is shown in Fig. 11, may also be provided that the lower strand 21 of the transport chain 19 is also guided by the stop projection 41. In this case, a further stop bar 85 is arranged on the underside of the housing part 27, through which the parts carrier 4 of the transport chain 19 can be held in position. This is accomplished by the stop projection 41, the stop bar 85 engages behind, and thus the force of gravity is counteracted by the stopper 41. This is particularly advantageous if the transport chain exceeds a certain total length, as by the weight of the lower strand 21, this would sag. The longer the lower strand 21, the greater the inclination of the transport chain 19 for sagging. The lower strand 21 of the conveyor chain 19, in particular the sub-carrier 4 are held in position by this mechanism, wherein the stopper projection 41 is moved relative to the stop bar 85 slidably thereto. The embodiments show possible embodiments of the transport system, which should be noted at this point that the invention is not limited to the specifically illustrated embodiment s variants of the same, but also various combinations of the individual embodiments are mutually possible and this variation possibility due to the doctrine of technical action by objective invention in the skill of those skilled in this technical field. So are all conceivable embodiments, which are possible by combinations of individual details of the illustrated and described embodiment variant, includes the scope of protection.

For the sake of order, it should finally be pointed out that for a better understanding of the structure of the transport system, these or their components have been shown partially unevenly and / or enlarged and / or reduced in size.

S u b e c u s e c tio n a tio n s

Production plant 36 recess

 Transport system 37 Transport level

 Part 38 front edge

 Part carrier 39 Bearing bore

 Transport direction 40 journals

Workstation 41 stop projection

 Part supply station 42 stop bar

 Base frame 43 bearing support

 Carrier housing 44 bearings

 Bottom 45 leadership role

Mounting level 46 Guide roller

 Frame construction 47 Guidance

 Bearing frame module 48 Guide

 Receiving opening 49 vertical and lateral guideway

Longitudinal beam 50 height guidance sb ahn

Handling device 51 engaging portion

 Guide wheel 52 guide section

 Guide wheel 53 Height and side guide surface

Transport chain 54 guide section

upper strand 55 vertical guide surface lower strand 56 recess

 Guide device 57 Distance measure

 Feed drive 58 Guide width dimension

 Brake drive 59 recess

 Reversing station 60 sealing lip

Diverter 61 Distance gap

 Housing part 62 control device

 Face plate 63 control circuit

 Support device 64 switch

 Deflection pulley 65 Voltage connection

Engagement groove 66 detection device

 Joint axis 67 evaluation unit

 Mounting plate 68 actuator

 Tab 69 receiving plate

Tab 70 tab 71 bearing bore

 72 leadership role

 73 Leadership

 74 guideway

 75 guideway

76 leadership

 77 cover

 78 tensioning device

79 slot guide

80 fasteners

81 tensioning wheel

 82 hold-down element

83 spring element

 84 additional bearing element

85 more stop bar

Claims

Patent claims 1. Transport system (2, 2 ') for conveying parts (3) by means of part carriers (4, 4') within a production s anläge (1) in the transport direction (5) successively arranged workstations (6) and / or parts delivery s stations (7), which has a base frame (8, 8 '), deflection wheels (17, 18) rotatably mounted thereon, and a transport chain (19, 19') guided around the deflection wheels (17, 18) with a leading, upper strand (20), which faces a transport plane (37; 37 '), and a returning lower strand (21), a feed drive (23) coupled to one of the deflection wheels (17, 18) for advancing the transport chain (19; ) in the transport direction (5), a between the guide wheels (17, 18) extending guide device (22; 22 ') for the leading, upper strand (20) of the transport chain (19; 19'), wherein the transport chain (19 19 ') comprises the parts carriers (4, 4'), characterized in that at least the upper St Rank (20) of the transport chain 19 is biased with a defined clamping force. 2. Transport system according to claim 1, characterized in that a feed drive (23) is formed by a direct drive, the drive motor is directly coupled to the first deflection wheel (17). 3. Transport system according to claim 1 or 2, characterized in that for applying the clamping force, a clamping device (78) is provided which acts directly on one of the deflection wheels (17, 18). 4. Transport system according to claim 1 or 2, characterized in that for applying the clamping force, a tensioning wheel (81) is provided, which at the lower strand (21) of the transport chain (19) between the two deflecting wheels (17, 18) is arranged. 5. Transport system according to one of the preceding claims, characterized in that the guide s device (22) on the base frame (8) with parallel parallel guides (47, 48) and the transport chain (19) on the guides (47, 48) Guide members (45, 46) supportable chain links, wherein on the one hand a first guide (47) and associated first guide members (45) each have a height guide surface (49, 53) and side guide surface (49, 53) and on the other hand, a second guide (48) and this associated second guide members (46) each form exclusively a height guide surface (50, 55). 6. Transport system according to one of the preceding claims, characterized in that the base frame (8) in a parallel to the transport plane (37) extending boundary plane and in the longitudinal direction of the guides (47, 48) extending stop strips (42) and that the transport chain ( 19) are provided on some of their articulated chain links on one of the transport plane (37) facing away from bottom with stop projections (41) which are arranged and designed such that the stop projections (41) on the advancing movement of the transport chain (19) along the guide s device (22) engage behind the stop strips (42). 7. Transport system according to claim 6, characterized in that on the guides (22) each have a running in the longitudinal direction of the stop bar (42) is formed. 8. Transport system according to claim 6 or 7, characterized in that in the stop bar (42) hold-down elements (82) are formed, through which the parts carrier (4) by means of spring elements (83) to the guides (47, 48) can be pressed. 9. Transport installation according to one of the preceding claims, characterized in that the base frame (8) lying in a parallel to the transport plane (37) extending boundary plane, and in the longitudinal direction of the guides (47, 48) extending, further stop strips (85) and that at least part of the length of the impact projections (41) of the chain links overlap these stop strips (85) on the upper strand (20) of the transport chain (19) facing side. 10. Transport installation according to one of the preceding claims, characterized in that the transport chain (19) comprises chain links produced from metal injection molded parts. 11. Transport system according to one of claims 1 to 7, characterized in that the transport chain (19 ') made of stamped and formed parts chain links comprises. 12. Transport system according to one of the preceding claims, characterized in that the transport system (2, 2 ') to a control device (62) connected to the optical detection device (66), in particular a camera system, by means of which a relative position (actual position) at least a part carrier (4, 4 ') in the transport direction (5) and / or transversely to the transport direction (5) can be detected, and that the control device (62) with an evaluation unit (67), of which in a nominal-actual comparison of a Manipulated variable is calculated, and an actuator (68) from which a working module at least one working station (6) is acted upon by the manipulated variable, is connected. 13. A method for conveying parts (3) by means of a transport system (2, 2 ') between in the transport direction (5) successively arranged working stations (6) and / or parts delivery stations (7), which transport system (2; the deflecting wheels (17, 18) are guided by a positive-locking transport chain (19, 19 ') with a leading upper strand (20) facing a transport plane (37, 37') and a return, lower strand (19) and parts carrier (4, 4 '), in which the parts carrier (4, 4') via a common, intermittent feed drive (23) in the transport direction (5) stepwise to the workstations (6) and / or Teilebereit- position s stations (7 ) and thereby accelerated in an acceleration phase and decelerated in a braking phase, wherein in the acceleration phase a first deflection wheel (17) is driven by the feed drive (23), characterized in that in the braking phase the first deflecting wheel (17) is driven by an electronically controllable drive motor and a second deflecting wheel (18) is braked by a brake drive (24) such that the leading, upper strand (20) between the deflecting wheels ( 17, 18) is tensioned. 14. The method according to claim 12, characterized in that in the acceleration phase of the transport chain (19, 19 ') and the brake drive (24) acts as a feed drive. 15. The method according to claim 12, characterized in that in the braking phase of the transport chain (19, 19 ') of the feed drive (23) reduces a drive torque and the brake drive (24) changes a braking torque depending on the drive torque of the feed drive (23). 16. The method according to claim 12, characterized in that in the braking phase of the transport chain (19, 19 ') of the feed drive (23) reduces a drive torque and the brake drive (24) by shorting voltage terminals (65) of an electric drive motor generates a braking torque ,