Method for forming seals on vehicle bodies

A method for forming seals on vehicle bodies produces by extrusion a sealing material strand to be processed to form a multiplicity of seals, coils the sealing material strand to form a transportable unit, transports the transportable unit to a processing site, and supplies the sealing material strand continuously at the processing site using the transportable unit to a processing device which forms the seals, wherein, within the scope of the processing, a portion of the sealing material strand to be applied to the relevant seal support seat and forming the seal is severed from the sealing material strand in each case. Within the scope of producing the sealing material strand, the sealing material strand portions which in each case form a seal are produced with a cross section changing in the longitudinal direction of the strand, and, within the scope of processing the sealing material strand, separating points which are required for severing the sealing material strand portions which in each case form a seal are determined by detecting markings which are produced on the sealing material strand before the transportable unit is formed and/or by detecting changes in the cross section of the sealing material strand that occur at certain longitudinal positions of the sealing material strand portions.

CROSS REFERENCE TO RELATED APPLICATIONS

This application. is the National Stage of PCT/EP2014/003190filed on Nov. 28, 2014, which claims priority under 35U.S.C. § 119 of German Application No. 10 2013 114 775.5 filed on Dec. 23, 2013, the disclosures of which are incorporated by reference. The international application under PCT article 21(2) was not published in English.

The invention relates to a method for the formation of seals on vehicle bodies, particularly vehicle doors or vehicle door frames, in which a sealing material strand to be processed to form a multiplicity of seals is extruded, the sealing material strand is coiled up or folded up, forming a transportable unit, the transportable unit is transported to a processing location, and the sealing material strand, at the processing location, is continuously passed to a processing device, being pulled out from the transportable unit, wherein during the scope of processing, a segment of the sealing material strand that forms the seal and is to be applied to the seal carrier seat in question is severed from the sealing material strand.

Methods of such a type are known, for example, from EP 1 733 839 B1 and EP 2 419 239 A1. In these known methods, seals are formed on the vehicle at the vehicle manufacturer, not, as until then, by application of sealing material pieces that have been prefinished at a specific length at the sealing material manufacturer, but rather from an extruded sealing material strand supplied in endless manner, from which strand segments are severed within the scope of processing, forming a seal, in each instance.

The invention is based on the task of expanding the application possibilities of such a method.

According to the invention, the sealing material strand segments that form a seal, in each instance, are produced, within the scope of production of the sealing material strand, with a cross-section that changes in the longitudinal strand direction, and, within the scope of the processing of the sealing material strand for severing the sealing material strand sections that form a seal, in each instance, required severing locations are produced with detection of markings that are produced on the sealing material strand before the transportable unit is formed, or/and determined by detection of changes in cross-section of the sealing material strand that occur at specific longitudinal positions of the sealing material strand segments.

Sealing material strands processed according to the state of the art have a constant strand cross-section in the longitudinal strand direction. By means of the invention, the production of seals on vehicle bodies from endlessly supplied sealing material strands is expanded to cover those application cases in which a sealing material strand segment, in each instance, having a cross-section that changes in the longitudinal strand direction is required, for example a sealing material strand segment that is reinforced in specific length regions, for example those provided for being laid around bends. According to the invention, the beginning and the end of the individual sealing material strand segments having a specific change profile of the cross-section in the longitudinal strand direction in each instance are determined using detection of markings that are assigned to a specific longitudinal position, with reference to such a sealing material strand segment. Alternatively or in addition to the determination of the location of the beginning and the end of the individual sealing material strand segments, a specific characteristic cross-section change that occurs in a specific longitudinal position of the respective sealing material strand segments can be detected, for example a change in the outer cross-sectional contour can be determined optically. When the total cross-sectional surface remains the same, changes in the location of material boundaries, for example between harder and softer rubber material, are possible changes in cross-section.

Preferably, within the course of processing of the sealing material strand, the severing locations are furthermore determined using measurements of the advance of the sealing material strand. For example, after detection of a characteristic change in cross-section, the location of which, with reference to the end of the sealing material strand segment, is known, the determination of the severing location takes place at the end of the sealing material strand segment, by means of a comparison of the known distance and the advancing length of the sealing material strand that has been determined continuously.

Preferably, the markings on the sealing material strand are produced during its production, within the course of extrusion, particularly by means of a device installed in the extrusion die or behind the extrusion die in the extrusion direction.

It is practical if the sealing material strand is formed with sealing material strand segments that serve to form a seal, in each instance, which follow one another directly, or with an intermediate segment between the sealing material strand segments, in each instance. The first alternative requires greater precision in the determination of the severing locations, as compared with the second alternative.

As will be explained below, the intermediate segments must be severed during the course of processing of the sealing material strand, as material pieces unsuitable for the formation of a seal, and sorted out as scrap.

Preferably, defective sealing material pieces are cut out from the sealing material strand at the sealing material manufacturer, before the formation of the transportable unit, wherein preferably, only connection abutment points remain as defects of the sealing material strand contained in the transportable unit.

Preferably, cutting out of sealing material pieces takes place to such an extent that defects of the sealing material strand, particularly connection abutment points, come to be placed only in intermediate segments. The intermediate segments can be very short and have only such a length that it can be ensured, within the scope of production tolerances, that no sealing material strand with two abutment points will be processed.

It is practical if markings that reach directly up to the beginning and end of the sealing material strand segments are formed as markings, in each instance. The severing locations can be determined with little effort, in this manner, by means of determining the marking ends.

It is practical if the markings are produced on the intermediate segments and preferably extend over the entire length of the intermediate segments.

In this way, it is ensured that the ends of the markings indicate the beginning of a preceding sealing material strand segment and the beginning of a subsequent sealing material strand segment, in each instance.

The method according to the invention can also be carried out, alternatively, in such a manner that defects of the sealing material strand independent of an intermediate segment are indicated by separate defect markings that differ from the markings. These defect markings then indicate that the sealing material strand piece in question is not suitable for formation of a seal, and must be severed and sorted out at the beginning of the next following sealing material strand segment that is suitable for formation of a seal.

The production of sealing material strands having sealing material strand segments, the cross-section of which changes in the longitudinal strand direction, preferably takes place by means of variation of the extrusion cross-section.

Alternatively, elastomer material that solidifies in a seal cavity can be injected from the outside. It is also conceivable to introduce solid material pieces into the seal cavity, in the extrusion direction, through the extrusion die. Finally, changes in cross-section can also be produced by means of cutting work on extruded strands, for example by means of lasers, water jets or punching tools.

A material strand1for formation of seals2that run around the circumference of vehicle doors3is unwound from a transport and supply roll4, and, by way of a buffer5, continuously supplied to a processing device6that produces the door seals. The vehicle doors3are transported to the line and away in cycles, for receiving the seals.

The processing device6comprises a transport and guide device7. The transport and guide device7shown in simplified manner, as a block, inFIG. 1, has not only a drive track but also drive and guide rollers distributed over the processing length of the material strand1, not shown in any detail. The drive and guide device7stands in connection with a control device8of the processing device6. The control device8can change the advancing speed of the material strand1, among other things, and stop the advance, if necessary.

In the example shown, the processing device6furthermore has a device9that optically detects markings applied to the material strand1at the strand manufacturer. A further component of the processing device6forms a severing device10for severing a segment of the material strand1that is required for the formation of a seal2, in each instance. The severing device10receives control signals from the control device8. The control device8furthermore controls an application device11, which applies the segment of the material strand1that forms a seal2, in each instance, to the vehicle door3in question, and connects it with the latter, i.e. glues it on. In the example described, a robot12holds and moves the vehicle door3relative to the application device11in such a manner that a sealing ring that runs around the circumference of the vehicle door3is formed by means of the continuously applied material strand segment, while the application device11remains in place.

It is understood that the application device itself could have a movement device by means of which the strand can be circumferentially connected with a door edge or with the opening edge of a door or of a vehicle hatch.

A first exemplary embodiment of a material strand1to be wound onto the supply and transport roll4is shown inFIG. 2.

The extruded material strand1has periodically recurring strand segments13having the length L, which segments each serve to form a seal. An intermediate segment14, which has a specific length l, in a normal case, is formed between the strand segments13, in each instance. In the example shown, a marking15extends over the entire length of the intermediate segments14.

The periodically recurring strand segment13has a specific length profile of its cross-section. In the example shown, reinforcements16and17that fill a cavity of the material strand1are formed at specific longitudinal positions of the strand segment13. When the strand segment13is installed, these reinforcements16,17come to lie at specific locations of the seal carrier, for example in bend regions.

The reinforcements16,17can be produced in different ways, for example by means of variation of the extrusion cross-section by means of the introduction of material pieces into the extrusion tool, or by means of injection of elastomer material that is capable of flow and solidifies within the cavity of the material strand.

It is practical if the markings15are applied during the course of extrusion of the material strand. The material strand1, which is wound onto the supply and transport roll4was examined for defects at the manufacturer of the material strand1, and defective segments were cut out. Sorting out defective segments took place in. such a manner that the resulting connection abutment points come to lie within the intermediate segments14. If an intermediate segment14contains such a connection abutment point22, the length1′ of this intermediate segment can deviate from the length1. Alternatively, with greater effort, sorting out defective segments could also take place in such a manner that intermediate segments having precisely the length1are formed. In the latter case, in particular, the marking15does not have to extend over the entire length of the intermediate segment14as will be explained below.

In the processing of the material strand1by the processing device6, the material strand1is advanced by means of the drive and guide device7, in accordance with the arrow18(FIG. 3). An advance measurement device21integrated into the drive and guide device7records the advance length. When the optical device9detects a front end of a marking15, in the advance direction, the control device8activates the severing device10after the advance length in question, by which the position of the device9and of the severing device10differ from one another, has passed through. The severing device10then severs the end of the leading strand segment, the front end of which has already been applied to the seal carrier by the application device11, at19. In the next processing step, the optical device9detects the back end of the marking15in question, in the advance direction, and again, by way of the control device8, triggers activation of the severing device10, which severs the intermediate segment in question at20.

In the method of procedure described above, the optical device9orients itself on the basis of the marking ends. At a constant length of the intermediate segments14, a shorter marking is sufficient. The severing location20is then determined by way of an advance length measurement.

The subsequent sealing strand13′ can now be processed next, and its back end can be severed in the manner described above, as can the next subsequent intermediate segment14′.

A material strand1acould also be wound up onto the transport and supply roll4, as shown inFIG. 4.

A material strand1ahas strand segments13athat follow one another directly, having a repeating length profile of their cross-section. Each of the strand segments13aserves for the formation of a seal. At the beginning25of each strand segment13ahaving the length L, there is a marking15a. AsFIG. 4shows, the regular sequence of strand segments13acan be interrupted in that a segment23having a connection abutment point22ais situated between two strand segments13a. The abutment point22awas formed after a defective material strand piece was cut out at the material strand manufacturer, and indicated with a marking24. The processing device6recognizes the marking24, which is interrupted in the longitudinal strand direction, as a defect marking.

In the processing of the strand1a, the control device8recognizes, on the basis of the defect marking24, that the strand segment23in question cannot be used for the production of a seal, and ensures that the segment in question, as it advances further, is not taken up by the application device11for processing, but rather is sorted out. The material strand1continues to run until the optical device9detects the next subsequent marking15aand brings about severing of the defective segment23by way of the control device8. In a normal case, severing of the strand segment that was processed, in each instance, takes place at the beginning of the marking15a, in each instance. Of course, the marking could also be applied in such a manner that this takes place at the end of the marking or in a predetermined longitudinal position of the marking.

A material strand1bshown inFIG. 5, having strand segments13bhaving a constant length L, for the formation of one seal each, and intermediate segments14bhaving a constant length l, has only a single marking26per strand segment13b. The marking26is situated at a predetermined longitudinal position of the strand segment13b. In the processing of the material strand1b, the optical device9detects this marking. Proceeding from its longitudinal position and the known length l of the intermediate segments14b, the respective severing locations19band20bare determined on the basis of an advance length measurement using the advance measurement device21.

Instead of the marking26, the optical device could also determine a prominent outer cross-sectional shape of the longitudinal cross-sectional profile of the strand segment13bthat occurs at a specific longitudinal position.

FIGS. 6 and 7show a particularly preferred exemplary embodiment of a material strand1c, which has periodically recurring material strand segments13chaving the length L, each serving for the formation of a seal, with a reinforcement17cin a specific longitudinal position of the material strand13c. There is a marking26cat the reinforcement17c. The front end of the marking26c, in the advance direction, has the distance L1from the front end25cof the material strand segment13cand the distance L2from the back end25c′ of the material strand segment13c.

If the aforementioned device9detects the front end of the marking26c, in the advance direction, for example, then the respective advance coordinates of the beginning25cand of the end25c′ of the material strand segment13care known at this detection time point. Further changes of the advance coordinates can be determined using the aforementioned advance measurement device21. In particular, the time points at which the beginning and end of the material strand segment13creach the position of the aforementioned severing device10can be determined.

According to.Fig 7, the periodicity of the material strand1cis disrupted as the result of an abutment connection22c. The abutment connection was formed at the manufacturer of the material strand1c, within the scope of an examination and sorting out of a defective strand region. A. separate defect marking24c, which is disposed on the strand in a different position from the marking26c, on the strand circumference, in this exemplary embodiment, faces toward the abutment connection22c.

If the aforementioned device9or a separate device for detection of such a defect marking24cdetects a defect marking24cwithin an advance length L1or L2, behind a marking26c, then the material strand region in question does not get processed, up to the front end of the next subsequent intact material strand segment13c, and is sorted out before it is taken up by the application device11.

In a further embodiment of a sealing material strand to be processed in endless manner, having markings26that indicate a sealing material strand segment for the formation of a seal, in each instance, defect markings such as the marking24ccan also be eliminated entirely.

This is because defective strand parts of the sealing material strand, which are unsuitable for the formation of a seal and contain an abutment connection that remains after defective strand parts have been sorted out by the manufacturer, for example, can already be detected solely by the fact that the periodicity of the markings has been disrupted. A distance between two markings that deviates from the length L clearly indicates such a defect, as long as it is avoided, during sorting out of defective strand parts by the manufacturer, that strand parts having precisely the length L or a whole-number multiple of it are sorted out. The length of the sorted-out strand part must deviate from this length so clearly that the periodicity is recognizably cancelled out.

If, during the course of processing of the sealing material strand1c, using the device9and the advance measurement device21(as well as using the control device8), a distance between two markings that is not equal to L is determined, then a strand part, the front end of which, in the advance direction, lies at a distance L1from the front marking question, in the advance direction, and the back end of which lies at a distance L2from the back marking in question, of the two markings, in the advance direction, is sorted out.

It is understood that the characteristics of the sealing material strands1,1a,1b,1cdescribed above can be combined with one another. Aside from a determination of the severing locations on the basis of disruptions of the periodicity of the occurrence of the markings15,15a,26,26cthat indicated the occurrence of a sealing material strand segment13,13a,13b,13c, in each instance, defect markings24,24ccan additionally be used to determine severing locations. Such defect markings can be differentiated from the markings15,15a,26,26cthat indicate the sealing material strand segments13,13a,13b,13c, in different ways, for example by means of the position on the circumference of the strand or the manner of the graphic representation.

In a particular embodiment, liner connection bridges, which must be formed at connection abutment points of a sealing material strand that has an adhesive surface covered by a liner, can serve as defect markings.

The markings that serve to indicate the periodically recurring sealing material strand segments can be modified in the event of the occurrence of defects, and can contain a graphic indication, for example, that a connection abutment point is situated ahead of or behind the marking, in the advance direction. Such modifications are possible if the marking is not produced directly during the course of extrusion but rather during the course of examination of the extruded material at the sealing material strand manufacturer.