Abstract:
A method for attaching a sealing profile to a vehicle body part includes the steps of pulling the sealing profile from a storage unit; passing the sealing profile through a first buffer which compensates for differences between incoming and outgoing speeds of the sealing profile; attaching an adhesive strip to the sealing profile continuously, the adhesive strip having a first adhesive layer facing the sealing profile and a second adhesive layer facing away from the sealing profile; passing the sealing profile with the attached adhesive strip through a second buffer which compensates for differences between incoming and outgoing speeds of the sealing profile; and rolling the second adhesive layer onto the vehicle body part. The adhesive strip is attached to the sealing strip in an assembly unit which heats the first adhesive layer as it moves around a press roller.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. national stage of International Application No. PCT/EP2008/000943 filed on 7 Feb. 2008. Priority is claimed on German Application No. 10 2007 010 421.0, filed on 1 Mar. 2007. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention pertains to a method for attaching sealing profiles to vehicle bodies or their parts, where the sealing profile is pulled from a storage unit, and a press roller is used to roll an adhesive layer carried on the sealing profile onto the vehicle body or a vehicle body part along a line provided for this attachment process. 
     2. Description of the Related Art 
     A method for attaching a seal to a vehicle door is known from DE 101 38 781 A1, in which the seal, in the form of an endless profile on a supply roll, is pulled from the supply roll, and an adhesive surface on the seal is rolled continuously around the vehicle door along a line provided for this attachment process. 
     In conjunction with this prior art and the present invention, the term “rolled onto” is intended to mean that the press rollers, for example, of a suitable application device are used to press the sealing profile continuously along a surface of a vehicle body or vehicle body part such as a vehicle door following a predefined installation line, the profile thus being attached in this manner. 
     The sealing profile in the process according to DE 101 38 781 A1 is in the form of an extruded profile to which an adhesive tape has been applied and which is wound up on a supply roll, from which it is pulled. The adhesive surface of the sealing profile is covered initially by a liner, which is pulled off before the seal is attached. The liner can be pulled from the adhesive surface by a robot, for example, which also carries the press roller. 
     The sealing profile wound up on the supply roll must be preassembled at the manufacturer&#39;s plant. It normally consists of the sealing profile and the adhesive strip applied to it, where the surface of the adhesive layer facing toward the outside is covered by the liner. The preassembly of the sealing profile, therefore, consists not only of the step of extruding the sealing profile but also the additionally required steps of gluing the adhesive strip to the sealing profile and of attaching the liner. 
     The attachment of the adhesive strip must be precisely coordinated with the extrusion process, which could otherwise be disturbed by this attachment step. In addition, it is necessary for the preassembled sealing profile to be to be packaged carefully for the trip from the manufacturer of the sealing profile to the user, such as an auto maker. Otherwise, there is the danger that the liner could separate prematurely from the adhesive layer, which would prevent the sealing profile from bonding properly to the vehicle body or vehicle body part. But even if the profile is properly packaged, there is still the danger that the liner can come loose during transport as a result of vibrations, internal stresses in the sealing profile, or the effects of weather. Bonding the adhesive strip to the profile during the extrusion process can also cause the quality of different lots of sealing profiles to vary. 
     Finally, a device for mounting a sealing strip on the flange of a sunroof opening or other opening in a car body is known from DE 197 04 327 C1, in which a supply roll is installed permanently in a storage unit structurally separate from the application device, and in which the sealing strip being paid out from the supply roll is buffered in a length buffer by means of at least one loop passing around two pulleys spaced a certain distance apart, this distance corresponding to the length required for the sunroof opening. 
     SUMMARY OF THE INVENTION 
     Proceeding from this prior art, the invention is based on the object of creating a method for attaching sealing profiles of the type indicated above, in which the previously described disadvantages arising from the assembly of the sealing profile are avoided or at least minimized. 
     The achievement of this object is based on the idea of integrating the assembly of the sealing profile in both time and space with the attachment of the sealing profile to the vehicle body or its parts. 
     This object is achieved specifically in a process of the type indicated above in that:
         after the sealing profile has been pulled from the storage unit, it passes through a first buffer, which compensates for differences between the incoming and outgoing speeds of the sealing profile;   an adhesive strip comprising the adhesive layer is then attached to the sealing profile;   the sealing profile provided with the adhesive strip passes through a second buffer, which compensates for differences between the incoming and outgoing speeds of the sealing profile; and   finally, the adhesive layer of the adhesive strip on the sealing profile is rolled onto the vehicle body or vehicle body part.       

     As a result of the inventive process, external influences such as weather conditions, vibrations, and internal stresses acting on the sealing profile are almost completely excluded, because the assembly of the sealing profile is integrated into the seal attachment process. 
     For the inventive process, an adhesive strip, preferably provided with an adhesive layer on both sides, is glued to the sealing profile. This first adhesive layer joins the adhesive strip to the sealing profile. The second adhesive layer joins the sealing profile provided with the adhesive strip to the vehicle body or vehicle body part. 
     The first adhesive layer of the adhesive strip preferably comprises a heat-activatable adhesive, whereas the second adhesive layer, which is provided on the opposite side of the adhesive strip, preferably comprises a pressure-activatable adhesive. The heat-activatable adhesive offers the advantage that the adhesive strip can be guided through the assembly unit of the device for implementing the process all the way to the press roller for the adhesive strip and only then activated by the controlled input of heat. To supply the heat, heating means are preferably installed at least upstream of the press roller (i.e., upstream with respect to the direction of movement of the sealing profile) to heat the sealing profile and thus to activate the heat-activatable adhesive adhering to the adhesive strip. In addition or as an alternative, heating means can be installed near the circumference of the press roller. These heating means are preferably located in the area of the segment of the press roller around which the adhesive strip is wrapped. 
     Because the adhesive strip passes through a buffer which compensates for differences between the incoming and outgoing speeds of the adhesive strip before the adhesive strip is rolled onto the sealing profile, the adhesive strip can be pulled continuously from different spools, where the adhesive strips from the different spools can be connected to each in an adhesive strip connector (also called a “splicer”). 
     The liner does not have to be attached to the adhesive strip in the inventive process as long as the sealing profile provided with the adhesive strip is guided by guide elements all the way to the press roller in the application unit in such a way that the adhesive layer of the adhesive strip, i.e., the layer which cooperates with the car body or car body part, does not come in contact with the guide elements. 
     Because of the time required to swap out one vehicle body or its part to which the seals have been attached for another, the process of attaching the sealing profiles is not continuous. So that, in spite of this, the quality of the attachment of the adhesive strip to the sealing profile in the assembly unit can be kept uniformly high, it is necessary for the adhesive strip to be glued continuously to the sealing profile. In the inventive method, the continuous attachment of the adhesive strip to the sealing profile is guaranteed in that the sealing profile passes through a buffer before the assembly of the seal and then through another buffer after the assembly of the seal, these buffers compensating for differences between the incoming and outgoing speeds of the sealing profile. As a result, the assembly of the sealing profile is disconnected from the application of the assembled sealing profile to the vehicle body or vehicle body part within the scope of conventional product swap-out times. Only then when the application of the assembled sealing profile to the vehicle bodies or vehicle body parts being supplied continuously to the application unit is interrupted for a long period of time will it also be necessary to interrupt the assembly of the sealing profile. 
     The buffers used to achieve this disconnection are formed by, for example, several guide pulleys, the distance between which can be varied and over which the sealing profile and/or the adhesive strip is guided. The distance is changed preferably by means of an adjusting drive. 
     The assembly unit of the inventive device for implementing the method comprises a storage unit for the adhesive strip. The storage unit can consist in particular of supply spools, on which the adhesive strip is rolled up. In the interest of the previously mentioned continuous assembly of the sealing profile, the storage unit of the assembly unit preferably comprises at least two spools carrying the same type of adhesive strip, the adhesive strip being pulled first from the one, then from the other spool. Once the adhesive strip of the first spool is used up, its end is connected to the beginning of the adhesive strip on the second spool in an adhesive strip connector (also called an automatic splicer). A buffer is located between the adhesive strip connector and the press roller of the assembly unit to compensate for the fact that, during the process of connecting two strips together, the incoming adhesive strip travels more slowly, whereas the speed of the outgoing adhesive strip remains unchanged. 
     If the position of the press roller of the assembly unit can be adjusted toward the sealing profile, it is possible for the assembly unit to process sealing profiles of different types. The positioning function guarantees that the adhesive strip can be applied with uniform pressure to the sealing profile regardless of the cross section of the profile. 
     At least the application unit, but possibly also the other components of the device, can be mounted on the arm of a robot. Alternatively, there is the possibility that the device for implementing the method could be designed to be stationary, in which case a robot arm would move the car body or the car body part against the press roller of the application unit so that the roll travels along the intended application line. 
     In an advantageous embodiment of the invention, the application unit comprises a cutting device for the sealing profile, by means of which the profile, upon completion of the process of the application, can be cut off straight across. 
     To obtain uniform conditions for the assembly of the sealing profile, preferably the first buffer, the assembly unit, and the second buffer of the device are installed in a climate-controlled chamber. The climate-controlled chamber makes it possible in particular to keep the temperature, the humidity, and the air pressure constant. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a schematic diagram of a device for implementing the inventive method; 
         FIG. 2  shows a schematic diagram of a assembly unit of the device according to  FIG. 1 ; 
         FIG. 3  shows a diagram of a sealing profile with an adhesive strip arranged on it; and 
         FIG. 4  shows various guide elements for the sealing profile and a cutting device for the sealing profile. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  shows a device, designated  1  overall, for attaching a sealing profile  2  to a vehicle door  3  by means of a press roller  4 . In the exemplary embodiment shown here, the sealing profile  2  is attached to a surface  5 , which extends up from the plane of the vehicle door  3  and thus from the plane of the drawing at more-or-less a right angle. The line provided on this surface for the attachment of the sealing profile  2  corresponds to the contour  5  of the schematically illustrated vehicle door. 
     In detail, the device includes a profile feeder  6 , first and second buffers  7 ,  8 , a assembly unit  9  located between the first and second buffers  7 ,  8 , and the application unit  10 . The application unit  10  includes the press roller  4  and guides  12  for the sealing profile installed upstream (with respect to the direction of movement of the profile) of the press roller. These guides  12  can, if needed, also be driven and thus push the sealing profile  2  toward the press roller  4 . In the exemplary embodiment shown here, the application unit  10  is stationary. A robot arm (not shown) moves the vehicle door  3  in such a way that the line on the door along which the sealing profile is to be attached travels past the stationary press roller  4 . 
     The two buffers  7 ,  8  and the assembly unit  9  are housed in a common climate-controlled chamber  13 . Each of the buffers  7 ,  8  comprises several guide pulleys  14   a,    14   b,  the distance between which can be adjusted. The distance  15  is changed by means of an adjusting drive (not shown) while the sealing profile  2  is passing around the guide pulleys  14   a,    14   b.  The profile feeder  6  consists of a supply spool  16  as a storage unit for the sealing profile, which is wound up on the spool and consists purely of the extruded profile and thus does not carry an adhesive strip. Downstream of the supply spool  16  (i.e., downstream with respect to the direction of movement of the sealing profile  2 ), there is a driven guide pulley  17  to pull the sealing profile  2  from the supply spool  16 . 
     The cross section of the sealing profile  2  wound up on the supply spool is shown in  FIG. 3 . The sealing profile  2  consists of a hollow profile  18 , on which a lip  19  is arranged, to which, in the assembly unit  9 , the adhesive strip  20  is attached just before the sealing profile  2  is attached to the vehicle door  3 . 
     The adhesive strip  20  is attached to the sealing profile  2  in the assembly unit  9  shown in detail in  FIG. 2 . The assembly unit  9  consists essentially of a storage unit  21  for the adhesive strip  20 , an adhesive strip connector  22 , a buffer  23 , a takeoff  24  for taking the adhesive strip from the storage unit  21 , and a press roller  25 , which deflects the adhesive strip  20  into the direction of movement  11  of the sealing profile  2  and presses the first adhesive layer  26 , consisting of a heat-activatable adhesive, of the adhesive strip  20  against the sealing profile  2 . Underneath the press roller  25 , on the bottom side of the sealing profile  2 , there is a support belt  27 , the upper strand of which supports the sealing profile  2  against the force being applied by the press roller  25 . The sealing profile is driven in the direction  11  by the belt in conjunction with two other drive rolls, which are located on the top side of the guide profile  2  at the level of the guide pulleys of the support belt  27 . 
     Upstream of the press roller  25 , i.e., upstream with respect to the direction of movement  11 , a heater  28  is provided, which heats the profile  2  as it passes along underneath. Another heater  29  is installed near the circumference of the press roller  25  and heats the heat-activatable first adhesive layer  26 . The force with which the adhesive strip  20  is pressed by the press roller  25  against the sealing profile  2  is supplied by a controlled positioner  30 , acting in the direction perpendicular to the direction of movement  11 . 
     The storage unit  21  of the assembly unit  9  includes two supply spools  31   a ,  31   b , each carrying the same type of adhesive strip  20 . The adhesive strip  20  is pulled first from the one supply spool  31   a , then from the other spools  31   b . Once the adhesive strip  20  of the supply spool  31   a  is used up, its trailing end is connected automatically to the leading end of the adhesive strip  20  on the supply spool  31   b  in the adhesive strip connector  22 . The supply spool  31   a  is replaced by a new, full supply spool. The short period of time during which the takeoff of the adhesive strip is paused to allow the adhesive strips of the supply rolls  31   a ,  31   b  to be connected to each other in the automatic adhesive strip connector  22 , is compensated in the buffer  23  by the shortening of the distance between the guide pulleys  14   a ,  14   b  so that the takeoff speed in the takeoff direction downstream of the buffer  23  remains constant. The takeoff  24 , making use of the oppositely rotating takeoff rolls  32  acting on both sides of the adhesive strip  20 , ensure that the takeoff speed remains uniform. 
     A second adhesive layer  33 , which is formed in particular by a pressure-activatable adhesive, lies on the side of the adhesive strip  20  opposite the first, heat-activatable adhesive layer  26  of the adhesive strip  20 . This second adhesive layer  33  is usually covered by a liner  34 , as shown at the bottom of  FIG. 3 . Shortly before the second adhesive layer  33  of the sealing profile  2  is rolled along the line on the vehicle door, this liner  34  is removed from the adhesive strip, possibly by means of a guide pulley, and wound up on a spool. 
     With the inventive arrangement, however, it is also possible to eliminate the liner  34  completely, as long as the sealing profile  2  provided with the adhesive strip  20  is guided by means of drive and guide elements, especially drive rolls and deflectors, all the way to the press roller  4  in the application unit  10 , in such a way that the second adhesive layer  33  with the pressure-activatable adhesive does not come in contact with the drive and guide elements. Especially after the adhesive strip  20  has been attached to the sealing profile  2 , the sealing profile may be transported only in such a way that no contact occurs between the second adhesive layer  33  and the drive and guide elements. 
       FIG. 4  shows various drive and guide means which satisfy this requirement.  FIGS. 4   a  and  4   b  show a bottom view and a cross-sectional diagram of a frictionless profile feeder  35 , which can be used in place of the support belt  27  and the corresponding rollers.  FIG. 4   c  shows a side view of a guide pulley downstream of the assembly unit  9 , i.e., downstream with respect to the direction of movement of the sealing profile.  FIG. 4   d  shows a partial cross section of the guide pulley according to  4   c.    FIG. 4   e,  finally, shows a cutting device  37  located in the area of the press roller  4 , by means of which the sealing profile attached to the vehicle door  3  is cut off straight across at the end of the application process. 
     The frictionless profile feeder  35  for a door sealing profile according to  FIG. 3  consists essentially of two co-rotating disks, which engage in the intermediate space between the hollow profile  18  and the lip  19  of the sealing profile  2 , as can be seen especially clearly in the cross-sectional diagram of  FIG. 4   b.  Because the adhesive strip  20  is on the outward-facing surface of the lip  19 , the second adhesive layer  33  does not come in contact with the rotating disks  38 . To prevent the rotating disks  38   a,    38   b  from slipping laterally out of the intermediate space  39 , the sealing profile  2  is guided laterally by a guide element  40 , which presses the seal toward the rotating disks under the action of springs bearing on the guide element  40 . A drive roll  41 , which pushes the sealing profile  2  in the direction of movement  11 , rolls along the top side of the hollow profile  18 . 
     The guide pulley  36  shown in  FIGS. 4   c  and  4   d  guides the sealing profile  2  in such a way that the adhesive strip  20  faces outward, whereas the sealing profile  2 , with its hollow profile  18 , rests in the groove  42  passing around the guide pulley. 
     The cutting device  37  shown schematically in  FIG. 4   e  consists of a cutting knife  42 , a counterknife  43 , which can turn around an axis of rotation, and an immersion bath  44  containing an anti-adhesive. The contact of the counterknife  43  with the second adhesive layer  33 , as the sealing profile  2  on which the adhesive strip  20  is adhering is being cut off, causes no problem, because, after every cutting operation, the counterknife  43  is rotated by a certain amount, so that the various effective cutting edges  45  of the counterknife dip one after the other into the anti-adhesive present in the immersion bath  44 . This prevents the cutting knife and the counterknife from becoming contaminated with residues of adhesive. Teflon or a plasma coating can be considered suitable as nonstick materials.