METHOD FOR STABILIZATION OF INTERMITTENT LENGTH BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to a method for stabilizing the length of an extruded strip product and more particularly to a method for intermittently stabilizing the length of a product. of extruded strip which is subsequently cut into separate pieces by inserting intermittent lengths of stabilizing members into the strip product, wherein the stabilizing members have a length that is less than the length of the molding members after being cut from the product of extruded strip. 2. Discussion of Related Art Protective and decorative trim or trim strips formed from thermoplastic materials that protect vehicle doors and provide an aesthetically pleasing appearance, are common in the automotive industry. Decorative finishing strips of this type can be formed by both injection molding processes and extrusion processes. Both of these processes have certain disadvantages that make them less ideal for high speed production, high volume decorative strip products. The use of an extrusion process, in general, is limited to forming products that have uniform cross sections through their length. It is also difficult to handle a hot extruded product, and move it through a cooling bath, without deforming the product and making it unsuitable for subsequent use. A problem that exists for extruded decorative finishing strip products has to do with shrinkage of the product that occurs after an extruded corrective finishing strip product has been cut to a length of a continuous extrusion and then subsequently cooled. The cooling of the extruded decorative finishing strip has resulted in a certain amount of shrinkage of the decorative finishing strip which affects the length of the strip. Typically, this shrinkage is in the order of about 1% the total length of the strip product. Because the automotive industry demands high tolerances with decorative components such as decorative finishing strips, the amount of shrinkage of the strip without further processing has generally been unacceptable for these purposes. To alleviate the problem of undesirable shrinkage of cut decorative trim strips, to date it has been known to co-extrude a thermoplastic decorative finishing strip product onto a stabilizing strip of length, wherein the stabilizing strip will limit shrinkage of the strip. of decorative finishing during cooling. The U.S. Patent No. 5,409,657 issued to Alma on April 25, 1995, granted to the assignee of the present application, and herein incorporated by reference, discloses a method for forming strip products from thermoplastic materials wherein a thermoplastic strip material is co-processed. Extrude on a metal backing layer. When metal and thermoplastic materials are co-extruded, then another problem arises that has to do with forming and contouring the ends of the extruded decorative finishing strip for use. Due to the nature of an extrusion process, the cross sectional shape of the decorative finishing strip is the same throughout its length. Therefore, certain end forming techniques have been made in decorative finishing strip products to provide convenient shapes to the ends of the strips after the strips are cut from a continuous extrusion. For example, U.S. Pat. No. 5,149,478 issued to Malm on September 22, 1992, granted to the assignee of the present application, and here incorporated by reference, describes a method for forming decorative finishing strips from a continuous extrusion. This method involves removing the material from end portions of the decorative finishing strips and then attaching the decorative finishing strip to a semi-rigid stretch of plastic in such a way that the end portions have a tapered appearance. Although the use of co-extruded continuous metal or other stabilizing layers has been effective in removing shrinkage from the decorative finishing strip productThis has interfered with the ability to form and constitute the ends of the decorative finishing strip product. Because this layer is stiffer than the thermoplastic layer, known techniques for forming the ends of the thermoplastic decorative finishing strip product have demonstrated product distortion and / or other processing difficulties, and have not been successful in shaping and constituting the ends of decorative finishing strip products that incorporate continuous stabilizer. What is required is a process that allows longitudinal stabilization of a decorative finishing strip product but does not affect the ability to form and constitute the ends of the decorative finishing strip product. Therefore, it is an object of the present invention to provide this process. SUMMARY OF THE INVENTION According to the teachings of the present invention, a method for intermittently stabilizing the length of a co-extruded product is described. In this process, a series of intermittent sections of a stabilizing insert are directed within a pair of co-operating forming rollers between continuous thermoplastic strips emitted from a split-current extrusion die. The forming rollers mold the thermoplastic material around the intermittent sections of the stabilizing insert to define a convenient form of an extruded decorative finishing strip product. The extruded decorative finishing strip product is then cut at sites between the intermittent sections of the stabilizing insert, such that the ends of the trimmed decorative finishing products do not include stabilizing inserts that may interfere with the end forming process of the finished decorative strip. Decorative cut strip cut. Additional objectives advantages and features of the present invention will be apparent from the following description and appended claims, which are taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION Figure 1 is a side view of a vehicle, including a decorative side and decorative finishing strip according to one embodiment of the present invention; Figure 2 is an extrusion system showing a process for extruding a stabilized product of intermittent length according to an embodiment of the present invention; Figure 3 is a side view of a cut extruded product that is formed by the process of the invention; Figure 4 is an end view of the extruded product of Figure 3 on line 4-4; and Figure 5 is a sectional end view of the extruded product of Figure 3 on line 5-5.
DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The following description of the preferred embodiments directed to a method for intermittently stabilizing an extruded decorative finishing strip product is simply exemplary in nature and is in no way intended to limit the invention or its applications or uses. Figure 1 shows a side view of a vehicle including a vehicle door 12. A decorative and protective finishing strip 14, formed from a process according to one embodiment of the present invention, is attached to an exterior panel of the door 12 and side panels 16 of the vehicle 10 by appropriate fastening, locating and securing devices (not shown) in a manner that is well understood in the art. The ends 18 of the strip 14 have been tapered by a convenient end forming process, known in the art, which provides an improved appearance to the strip 14. The decorative finishing strip 14 provides decoration to the vehicle 10, and also protects the paint finish of the vehicle door 12 and the side panels 16 against scratches, scrapes and dents, which result from contact with rigid objects, tanes like other vehicle doors, around the vehicle 10. Decorative finishing strips of the type of Decorative finishing strip 14 including exposed decorative surfaces, co-extruded on top and bottom panels, and / or? exi romos I orrtw os IB, are well known cp I d ¡con i e < ? i 'iqurd i lust r a sisl or ext rusion? () what I heard; dpl icdblo pfjrd produi r I < j l i r o «jcdbddo cf rdl i vo M I ', I
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? x- > The use of a compatible and visually similar stabilizing material (discussed below) can be used to determine the effectiveness of a single (or other) ion, such as those known in the art. to provide the acceptable visual appearance and recycling capacity at the end cut This will allow the cutting of parts through the stabilizing material at increased production speeds A pair of cooperating forming rollers 34 and 36 receive the thermoplastic strips 26 and 30 for molding the strips 26 and 30 together in a convenient manner The forming rollers 34 and 36 move in a synchronized relationship, and have a cooperating outer surface configuration defining an opening (not shown) between the rollers 34 and 36 forming a continuous extrusion 38 to its desired final cross-sectional configuration., the rollers 34 and 36 mold the heated and foldable strips 26 and 30 in the continuous extrusion 38 to have a convenient cross section. The holes 28 and 30 may have a shape that generally defines the cross-sectional shape of the strips 26 and 30 to be similar to the continuous extrusion 38. The molded thermoplastic strips 26 and 30 exit the rolls 34 and 36 as the extrusion continue 38 which is subsequently subsequently cooled by a cooling apparatus (not shown). In one example, the material of the strip 26 provides an exposed surface and the material of the strip 30 forms a rigid backing layer for a product such as the decorative finishing strip 14 as is well understood in the art. In order to prevent the continuous extrusion 38 from shrinking during cooling, a stabilizing insert of length 40 is placed between the plastic strips 26 and 30 before the strips 26 and 30 are formed by the rollers 34 and 36. In one embodiment , the material of the stabilizing insert 40 is aluminum, but other materials such as steel, may also be applicable for certain embodiments. The insert 40 is unwound from a roll 42, and enters the opening defined by the rollers 34 and 36 between the strips 26 and 30, such that the extrusion process produces the thermoplastic continuous extrusion 38 to include a stabilizing insert formed therein. of a thermoplastic outer layer. A mold or forming roller (not shown) can be provided to constitute the insert 40 in a convenient cross-sectional shape before the insert 40 is inserted into the rollers 34 and 36. According to the present invention, a cutter and spacer device 44 , cuts the stabilizing insert 40 which is unwound from the roll 42 and intermittently applies sections of the stabilizing insert 40 to the rollers 34 and 36 which are spaced a suitable distance. In this manner, the continuous extrusion 38 includes spaced stabilizing insert sections 46, where portions 48 of the extrusion 38 do not include metal insert sections 46 as illustrated. In an alternate embodiment, the device 44 may be a reservoir that holds a pre-determined amount of pre-cut stabilizing inserts and supplies the inserts one after another in a spaced relation to the rollers 34 and 36. After the continuous extrusion 38 at least something has cooled, a cutter 50, positioned relative to the continuous extrusion 38, cuts the continuous extrusion 38 into pieces of convenient length to form a plurality of sections of extrusion strip. Figure 3 shows a longitudinal view of a strip product 52 that has been cut from the continuous extrusion 38, and includes a stabilizing insert 54. The strip product 52 has undergone subsequent end processing to form tapered ends 56. The strip product 52 can be used as the decorative finishing strip 14 or other convenient purposes. As it is apparent to observe the strip product 52, the stabilizing insert 54 does not extend within the tapered ends 56. Therefore, the stabilizing insert 54 does not interfere with the end forming processes to form the tapered ends 56, as shown in FIG. discussed earlier. The system 20 is dimensioned such that the insert sections 46 are sufficiently spaced to form cut strip products, wherein the ends of the product are of sufficient length to accommodate different types of end forming techniques known in the art. The cutter 50 is regulated by a convenient control device 58, such that the cutter 50 sections the portion 48 that does not include the stabilizing insert sections 46 as illustrated. The length of the portion 48 may be different for different desired results. Figure 4 shows an end view of strip product 52 on line 4-4 of Figure 3, to show end 56. As it is apparent in this view, the metal insert is not visible. However, Figure 5 shows a sectional view of the strip product 52 on the line 5-5 of Figure 3 to reveal the insert 54 therein. As apparent in these views, the cooperating rollers 34 and 36 form the continuous extrusion 38 to have a rounded upper surface 60 and a flat rear surface 62. In one example, the rounded surface 60 will be formed from the strip 26 and would be a surface exposed for the decorative finishing strip 14 and the flat rear surface 62 will be formed from the strip 30, as the surface is flush or level against the door of the vehicle 12. The percent of the length of a strip product formed by the present invention, which does not include a stabilizing insert, can vary from product to product. In one example, a strip product of 127 cm (50") will have a length of 124.5 cm (49") of a stabilizing insert therein such that 1.27 cm (1/2") of the strip product in each The end does not include a stabilizing insert, therefore, the strip product in this example will only shrink 1% from 2.54 cm (1"). 1.27 cm (1/2") at each end of the strip product provides sufficient length to provide end formation without interference from the stabilizer insert.Of course, other end forming techniques may require more or less length not including the metal insert. The above discussion simply describes and illustrates exemplary embodiments of the present invention, A person skilled in the art will readily recognize from this discussion, and from the accompanying drawings and claims, that various changes and modifications may be practiced without departing from the spirit and scope of the invention. the invention as defined in the following claims.