| System for the automatic application of self-adhesive protective film to vehicle bodies -> Monitor Keywords |
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  System for the automatic application of self-adhesive protective film to vehicle bodiesThe Patent Description & Claims data below is from USPTO Patent Application 20070284046. Brief Patent Description - Full Patent Description - Patent Application Claims
[0001] The invention relates to a system for the automatic application of self-adhesive protective film to vehicle bodies according to the preamble of claim 1, as emerges as disclosed, for example, from DE 198 09 515 A1, which in the following text is cited as [1] for short. [0002] It is primarily the horizontal body parts--three in conventional sedans--namely the hood, roof and rear panel, which are to be protected by having an appropriate piece of a self-adhesive protective film stuck over them for the transport of the new vehicle from the fabrication site to the vehicle dealer. The system disclosed by [1] for the application of the protective transport film intrinsically represents a small production line comprising a plurality of workstations. Therein, the finally assembled vehicles standing on their own wheels and to be stuck are conveyed cyclically through the various stations of the application system; during an application of a piece of protective film, the vehicles are temporarily stopped. [0003] In order to be able to understand the present invention correctly, it is necessary to assume correct understanding of the mode of operation of the application system disclosed by [1], for which reason this system is to be discussed in more detail first. [0004] In a first workstation of the application system according to [1], the supply rolls of the protective film are arranged to be stationary and centrally above the conveyor line with the roll axis located transversely with respect to the transport direction; the film is therefore drawn off the supply rolls in the transport direction. In this case, for each of the three aforementioned body parts, a separate supply roll is provided in each case, whose width measured in the axial direction corresponds to the length of the associated body part measured in the body longitudinal direction. Each of the three supply rolls is arranged at a different height, so that a piece of film can be drawn off from each of the three rolls as required. The supply rolls are in each case dimensioned to be sufficiently large that they contain the film needed for at least one working shift. [0005] In the known application system, in the drawing-off direction beside each of the supply rolls, in each case an appropriate piece of film is held stationary and stretched out horizontally by two suction strips at a distance, this piece of film not yet having been cut off the supply roll. The adhesive side of this piece of film points downward. Perforation lines are made in this stretched-out piece of film by means of a heated cutting tool by a first working robot in an accurate contour and in a defined position from the non-adhesive upper side. Regions of the protective film that are not needed can later be removed along these perforation lines. The three pairs of stationary suction strips each stretching out a piece of film--just like the supply rolls as well--are arranged in the vertical direction at such a vertical distance from one another that the working robot drawing the perforation lines can reach without hindrance with its working tool between two pieces of film stretched out one above the other. [0006] Parallel beside each of the front suction strips facing away from the respective supply roll, in each case there is arranged a cutting bar having a cutting knife that can be moved therein, with which a piece of film drawn off for further processing and already provided with perforation lines can be cut off the supply. Furthermore, in each of the suction strips stretching out the piece of film, at the ends, that is to say both on the right and left in each case, there are arranged mechanical holding tongs that can be opened and closed mechanically, which reach around the film at the side edges on the upper and underside with their tong snout. These holding tongs hold the film temporarily, for example during the transfer to a suction strip of another working robot, or stretch out the film in the transverse direction after a drawing-off operation, in order that the film can then be picked up by the suction strips of the unwind station again without any defects or creases. [0007] The pieces of film held stretched out and provided with a perforation line are picked up by a first application robot for the purpose of further processing, said robot being provided with a suction strip at the wrist of its working arm. This first robot is set up laterally beside the conveying line of the vehicles and can move in the longitudinal direction between unwind station and application station. During the film transfer to the application robot, first of all the two holding tongs of the front suction strip on the unwind side close and hold the stretched-out piece of film at its front end firmly at the side edges and stretch out the film in the transverse direction; at the same time, the suction strip on the unwind side releases its hold on the piece of film and moves laterally by at least the placement width in order to create space for the suction strip of the aforementioned application robot, which is placed there and picks up the piece of film. The rear suction strip of the unwind station close to the roll is then vented, so that the perforated piece of film is still stretched out only between the supply roll and the suction strip of the application robot. The latter then draws a predetermined length of film horizontally off the supply roll, whereupon the suction strip of a second application robot is placed on the rear end of the piece of film that is drawn off, that is to say beside the aforementioned cutting bar, said robot being arranged on the opposite side of the vehicle conveying line and picking up the rear end of the piece of film drawn off. The front suction strip on the unwind side is then also moved into its working position directly beside the cutting bar again and both suction strips on the unwind side are activated. Thus, the film drawn off is held firstly by the two stationary suction strips of the unwind station and by the suction strips of the two opposite application robots. The piece of film held by the application robots is then separated from the stationary, stretched-out piece of film by means of the knife bar, and the two application robots move the piece of film held by them into the application station, pivoting the piece of film initially stretched out in the longitudinal direction transversely with respect to the conveying direction of the vehicles with a mutually synchronously coordinated movement. In this orientation of the piece of film picked up by the application robots, it can be aligned over the associated body part, brought close vertically and applied. [0008] Since, in most cases, as stated, three horizontal body parts have to have protective film stuck over them, the procedure outlined has to be repeated three times, namely with the appropriate piece of film in each case on each of the three body parts of a vehicle. These application procedures to be carried out three times could be carried out one after another with a time offset by the same pair of opposed application robots, which would lead to a relatively long cycle time. In order to shorten the cycle time, the application system according to document [1] accordingly proposes two pairs of opposed application robots which operate approximately simultaneously; however, the respective piece of film still has to be picked up from the unwind station by the two pairs of robots with a time offset, for reasons of space and for reasons of accessibility. The third body part then has to have its application carried out by one of the two pairs of robots with a time offset in relation to the two first parts of the body to which applications were made simultaneously. In principle, it would also be conceivable to provide three pairs of opposed application robots in the application system, so that all three body parts could have simultaneous applications. However, this would presuppose a further application station for the third pair of robots and a separate, associated unwind station. The space required and the investment for this purpose are obviously not in a tolerable relationship with the gain in productivity, for which reason in [1] only two pairs of robots are provided in the application system. [0009] The system disclosed by [1] for protective film application therefore has a total of five industrial robots, which must all be capable of movement under computer control parallel to the conveying direction of the vehicles to be treated, to a certain extent as a seventh robot axis. The cycle time of the protective film application is determined by the time required for two application procedures to be carried out with a time offset, each of which comprises drawing a perforated piece of film from the unwind station, re-orienting this piece of film in the transverse direction, aligning it with the associated body part, and the actual application of the piece of film. In the case of the simultaneous processing of two pieces of film, with regard to the time required it is also necessary to take into account the fact that the "fetching" of the two pieces of film from the unwind station can be carried out only with a time offset, for reasons of accessibility. Despite the relatively high investment for the application system, the productivity is therefore not particularly high. [0010] Added to this is the fact that, because of the stationary and very high mounting of the heavy supply rolls, these cannot be lifted into the unwind station by using conventional industrial trucks. Instead, a separate bridge crane system has to be provided for the roll change in the application system, which increases the investment. Incidentally, the very heavy supply rolls must not be transported or stored horizontally, since they can acquire flat points as a result, which would interfere during processing and would impair the protective function locally. Instead, the heavy supply rolls must contain separate cores consisting of steel, with which the supply rolls can be handled and can be kept in separate transport frames, likewise consisting of steel, during transport and storage. The relatively expensive cores and transport frames have to be sent back to the film manufacturer for reuse after the supply roll has been used up, which entails costly logistical effort. [0011] It is an object of the invention to improve the application system on which the generic type is based with regard to lower investment costs with a simultaneous increase in productivity. [0012] According to the invention, this object is achieved by the characterizing features of claim 1. The solution according to the invention primarily concerns what is known as the system layout of the application system, that is to say features which refer to the system as a whole. The invention is first to be assessed briefly in the following text with regard to lower investment and operating costs and then with regard to the increase in productivity, before an exemplary embodiment is described in detail. [0013] The cause of saving a substantial part of the investment costs is the supply rolls integrated in the robot tool for each of the pairs of robots. As a result, fetching and careful pivoting of a piece of film from a central, fixed unwind station is avoided and moving the application robots in the transport direction becomes dispensable. As a result of omitting the movement device of the application robots, these become quite considerably less expensive, since the movement devices are large parts to be fabricated with high accuracy and which are very expensive to produce. In addition, the supply rolls are very small and can be installed in magazines close to the ground; dispatch containers can be handled with conventional industrial trucks, for example fork stackers, and individual supply rolls can readily be handled manually. The roll change can be carried out automatically by the application robots, given a suitable construction of the roll magazine and the application tool. The small supply rolls can be provided with inexpensive disposable cores and, because of their low weight, can readily be transported and stored horizontally. To this extent, logistical efforts loading the operating costs for the monitored return of expensive empty goods are not necessary. Because of the supply rolls integrated into the tools, the likewise quite costly bridge crane system for high loads, which was necessary in the prior art for loading the unwind station arranged high overhead with the heavy supply rolls, is also dispensed with. All in all, the investment and operating costs of the application system according to the invention are considerably lower than in the prior art on which it is based. [0014] Furthermore, the new application system permits higher productivity, but this is achieved by using a further pair of application robots as compared with the prior art. On account of the use of three pairs of application robots, all three body parts to be treated can be stuck simultaneously, which reduces the cycle time considerably as compared with the prior art. There, three pairs of--movable--application robots are used only at the expense of a further unwind station arranged overhead. Since the supply rolls are arranged decentrally, new pieces of film can be drawn off the rolls simultaneously, which has a beneficial effect on the cycle time. Despite the present readily possible use of a total of six--stationary--industrial robots, there is nevertheless no additional investment expense as compared with the prior art, even if the system illustrated in [1] having a total of five industrial robots is used for the comparison. The one additional--stationary--industrial robot causes far lower investment costs than are saved by omitting other system components required in the prior art. It must certainly be admitted that the cycle time in the application system according to the invention is not determined solely by the application procedures running simultaneously but that the pieces of film also have to be provided with perforation lines within the cycle time, specifically before the application of the pieces of film, which is also carried out by the application robots. Perforation and application are therefore carried out with a time offset within the cycle time, which is determined by the time duration of the two procedures. In this connection, it is necessary to know that the perforation of the stretched-out pieces of film with the operating means proposed by the invention requires only a fraction of the time of the application of the film. Therefore, despite time-offset perforation and application, a shortening of the cycle time as compared with the prior art with two application procedures within one cycle time is nevertheless achieved. [0015] Expedient refinements of the invention can be gathered from the subclaims. Otherwise, the invention will be explained further below by using an exemplary embodiment illustrated in the drawing, in which: [0016] FIG. 1 shows an exemplary embodiment of an application system according to the invention in an outline illustration, [0017] FIGS. 2a to 2d show various working phases of the first application station of the system according to FIG. 1, in each case illustrated in an elevation taken in the plane II-II, [0018] FIG. 3 shows an enlarged individual illustration of the detail III from FIG. 2a, specifically of the two interacting application tools of the application robots located opposite each other, [0019] FIG. 4 shows an enlarged individual illustration of the detail IV from FIG. 1 as an elevation, specifically the perforation tool and its mounting, a detail from this in turn being illustrated enlarged, and [0020] FIG. 5 shows a perspective individual illustration of a small supply roll having a disposable core tube consisting of an inexpensive material. [0021] The exemplary embodiment illustrated shows a system for the automatic application of self-adhesive protective film to the roof 2, the hood 3 and the rear panel 4 of vehicle bodies 1. The system comprises a plurality of workstations arranged one after another, specifically two application stations 9 and 10 equipped with robots and a manual workstation 11. The vehicle bodies to be treated are conveyed through the workstations by means of a horizontal conveyor 8 laid in the shop floor. Said conveyor brings the vehicle bodies to a standstill in each of the workstations, in each case in a defined working position, in order to carry out certain tasks. Arranged on this and the other side of the horizontal conveyor, in each case in pairs and in a mirror-image fashion in relation to each other, are application robots, that is to say industrial robots 12a, b and 13a, b and 14a, b for the joint handling and application of one piece of film 24 in each case during its processing. The application robots will be discussed in more detail further below. In the application system, supply rolls are also held in a defined position, from which pieces of protective film can be drawn off by the application robots in a specific length and can be cut off. By means of a suitable perforating device, likewise provided in the system, perforation lines can be drawn with accurate contours in a piece of film held stretched out. These devices are also to be discussed in more detail further below. [0022] The two separate application stations 9, 10 in the system and further features described below are provided, according to the invention, with regard to lower investment costs and a simultaneous increase in productivity. The fact that a total of three pairs of application robots located opposite each other and working together are provided in two application stations means that all three regions of the body to be protected can be stuck simultaneously. In accordance with the distribution, one application station 9 is given one pair (12a, b) and the other--station 10--is given two pairs (13a, b and 14a, b) of industrial robots arranged opposite each other for the joint handling and application of one piece of film in each case. [0023] The application station 9 having only one pair of application robots 12a, b is provided for the treatment of the roof area 2 of the body 1, while the application station 10 is provided with two pairs of opposed application robots 13a, b; 14a, b for the application of a piece of film 24 in each case corresponding to the hood area 3 and the rear panel area 4, respectively. The roof area needs the largest piece of film and, accordingly, the largest application tools 18, 19 on the working arm 16 or on the wrist 17 of the robot 12a, b, which in turn requires most space when handling the piece of film 24 to be applied. For this reason, the two roof application robots 12a, b are advantageously arranged on their own in the workstation 9. By contrast, the two other body areas to be protected--hood 3 and rear panel 4--need substantially smaller pieces of film and the robots accordingly need smaller robot tools 18', 19' and 18'', 19'', respectively, and less room to move. In addition, these body areas are located far away from each other on the body, so that the two pairs of application robots cannot interfere with each other when working. For this reason, the two pairs of robots 13a, b and 14a, b for the treatment of hood and rear panel are arranged in a common application station--station 10. [0024] The base element 15 of each application robot 12a, b; 13a, b; 14a, b is arranged in a cost-effective way to be stationary in the respective application station 9, 10, that is to say immovable with respect to the conveying direction of the horizontal conveying device 8. To be specific, each application robot is arranged beside the position of the associated body part 2, 3 or 4 which the robot has to process and which this body part assumes when the body is at a standstill. Moving the robots in the conveying direction, that is to say in the longitudinal direction of the application system, is not necessary in the system layout according to the invention. Continue reading... Full patent description for System for the automatic application of self-adhesive protective film to vehicle bodies Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this System for the automatic application of self-adhesive protective film to vehicle bodies patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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