Title of Invention

METHOD FOR PRODUCING A STRIP-LIKE, ELONGATED SPRINGY ELEMENT FOR SUPPORTING A RESILIENT WIPER STRIP

Abstract

Method of producing a strip-like, elongated springy element (12) for supporting a resilient wiper strip (22) of a windscreen wiper for vehicles, which has two spring rails (26, 28) that are located at a distance (24) from each other and substantially parallel to each other and which, at least at their two end sections, are firmly connected to each other by means of transverse webs (30) which are arranged on one strip surface (14) of the spring rails and bridge across the distance (24), characterized in that the prefabricated spring rails (26, 28) of a plurality of supporting elements (12) are firmly connected to one another in pairs and aligned substantially parallel to one another by means of at least one strip-like retaining element (44) which is aligned transversally with respect to the spring rails, in that the grid-like composite (54) obtained in this way is subjected to at least one method step, after which, by separating the retaining element (44) between the respective pairs of spring rails (26, 28), the supporting elements (12) are detached from the composite (54).

Full Text

A Field of the invention The present invention relates to a method of producing a strip-like, elongated springy element for supporting a resilient wiper strip. Prior Art A supporting element similar to the supporting element being discussed here comprises longitudinal rails which are connected by bridge webs, and is disclosed, for example, by DE-A 100 25 708. Such a supporting element is usually produced in that after the spring rails and the bridge webs have been aligned, these bridge webs are welded to the spring rails. Then, the raw individual supporting elements formed in this way are subjected to further method steps. These further method steps can consist in the stresses possibly present in the raw supporting elements being eliminated by means of heat treatment and, after that, the raw supporting elements being subjected to a prescribed surface treatment which, for example, can consist in rust removal, galvanizing, painting etc of the blanks. For this purpose, the supporting elements located in transport containers have to be removed from there, in each case moved into a predetermined treatment position and then supplied to the appropriate unit carrying out the desired treatment. Such a method of producing supporting elements requires again and again intermediate steps which can only be carried out manually and are therefore costly. The WO 98/50261 discloses a wiper blade comprising a supporting element, which is made of one piece and does not have two separate springs which have to be connected. Therefore this document cannot give any hint to a method to connect single rails at a distance from each other and substantially parallel to each other at least at the two end sections. The WO 98/01326 discloses a wiper blade having a supporting element with two longitudinal rails, which are of one piece on one end section and which are clamped together at their other end section. There is no hint to connect a plurality of such support elements in pairs and aligned substantially parallel to one another by means of at least one strip like retaining element which is aligned transversely with respect to the spring rails, in that a grid-like composite is obtained. The DE 19822451 discloses a wiper blade comprising a support element, which is made of one piece and does not have two separate springs which have to be connected. Therefore this document cannot give any hint to a method to connect said two rails at a distance from each other and substantially parallel to each other at least at the two end sections. The JP 09-285834 solves the problem to improve the corrosion resistance by plating or painting the inside circumference face of a through hole and the front face of an engaging claw. There is no strip like, elongated supporting element having two spring rails that are located at a distance from each other and are substantially parallel to each other. Advantages of the invention In the production method according to the invention, having the features as described herein. Accordingly the present invention provides a method of producing a strip-like, elongated springy element for supporting a resilient wiper strip of a windscreen wiper for vehicles, which has two spring rails that are located at a distance from each other and substantially parallel to each other and which, at least at their two end sections, are firmly connected to each other by means of transverse webs which are arranged on one strip surface of the spring rails and bridge across the distance, characterized in that the prefabricated spring rails of a plurality of supporting elements are firmly In addition, in the composite the obvious thing is to fix the wiper-blade-side half of a device for connecting the wiper blade to a wiper arm, since all the supporting elements can be supplied without further effort and in a clearly defined position to an assembly station responsible for this. The separation of the individual supporting elements from the composite is advantageously carried out along the outer longitudinal edges of both its spring rails. As a result, the waste is limited to a minimum. The small rough cut edges which are produced in the process are likewise protected against corrosion by means of remote action in the galvanized supporting element. In order that a distribution as specified of the wiper-blade contact pressure on the screen to be wiped is ensured, the spring rails are provided in their longitudinal direction with a curvature on whose outer side, facing away from the screen, the belly-like [sic] retaining element is fixed. Further advantageous developments and refinements of the invention are specified in the following description of an exemplary embodiment illustrated in the associated drawing. Drawing In the drawing. Figure 1 shows a supporting element produced by the method according to the invention in a perspective illustration, not to scale, Figure 2 shows a plan view, in a reduced illustration, of a plurality of supporting elements according to Figure 1 which, according to the invention, are firmly connected to one another by retaining elements. Figure 3 shows the arrangement according to Figure 2 seen in the direction of the arrow III in Fig. 2, Figure 4 shows a detail designated by IV in Figure 2 in an enlarged illustration, Figure 5 shows a section through the arrangement according to Figure 4 along the line IV-IV, Figure 6 shows a schematic breakdown of the individual method steps which belong to the method according to the invention, and Figure 7 shows a side view, not to scale, of a wiper blade provided with the supporting element according to Fig. 1 and intended for screens of motor vehicles. Description of the exemplary embodiment A wiper blade 10 illustrated in Figure 7 has a springy supporting element 12 which is elongated and curved in the longitudinal direction (Figs. 3 and 7) , and in Figure 1 is illustrated separately, not to scale and in extended form. On the upper side 14 of the supporting element 12 facing away from the screen to be wiped -this is the outer width [sic] of the supporting-element curvature -, the dash-dotted lines show the principle of the wiper-blade-side half 16 of a connecting device with the aid of which the wiper blade 10 can be detachably connected to a driven wiper arm 18 guided on the bodywork of a motor vehicle. On the underside 2 0 facing the screen - this is the inner side of the supporting-element curvature - an elongated, resilient wiper strip 22 is arranged parallel to the longitudinal axis (Figures 1 and 5) . As can be seen in particular from Figure 1, the supporting element 12 has two spring rails 26 and 28 aligned at a distance 24 from each other and parallel to each other. The two spring rails 26 and 28 are connected to each other at their two end sections by means of transverse webs 30 and 32 arranged on their upper side 14, The transverse webs 30 and 32 have a bridge-like shape, so that they cross over the distance 24 between the two spring rails 26 and 28 with their centre section 34 elevated. The transverse webs to the next pair of spring rails is found again in the pitch of the moulded sections 48 in the strips 44. In addition, it is also important that the moulded sections 48 in the two strips 44 are aligned with one another as viewed transversally with respect to the longitudinal extent of the strips. If, then, as the strips 44 are unwound in their reels 42 of strip material in their moulded sections 48, [lacuna] pass into the position illustrated in Figure 5 with respect to the pairs of spring rails 26, 28, the spring rails 26, 28 are firmly connected to the strips 44 at both their end sections, This method step can be achieved, for example, by means of a welding method known per se (method step B). With the method step B, therefore, the prefabricated spring rails 26, 28 of a plurality of supporting elements 12 are firmly connected in pairs and aligned parallel to one another to the two strips 44, which are aligned transversally with respect to the spring rails and formed in the manner of a strip. By means of the building strips [sic]44 serving as retaining elements, the result is thus a mat-like or grid-like composite 54 which, because of the curved spring rails 26, 28, has a shape similar to a gutter which, in a simple way, can be supplied to further method steps. Because of the preceding method steps, it is possible for stresses, which impair the quality of the wiping performance of a windscreen wiper, to be present in the spring rails 26, 28. It may therefore be expedient for the grid-like composite 54 (Figures 2 and 6) to be subjected to heat treatment to eliminate these stresses (method step C) . In order to protect the supporting element 12 against aggressive environmental influences, it is expedient for the grid-like composite to be galvanized in accordance with a further method step (D), In the event of pregalvanized strip being used for the retaining elements 44, the zinc coating can be partially removed in a suitable way in an intermediate step there, before method step B. After that, according to the exemplary embodiment, the composite 54 is painted in a further method step E. Finally, the composite passes into a separating station, where the separation of the supporting elements 12 in the composite 54 is carried out. In the process, the two strips 44 acting as a retaining element are separated out from the composite along the outer longitudinal edges of its two spring rails. The result is therefore a piece of waste, which is provided with the reference number 56 in Figures 4 and 5. Although when the supporting elements 12 are separated out of the composite 54, small, rough cut edges 58 result (Figs. 4 and 5), these do not offer any points of attack for environmental influences, since in the case of galvanized supporting elements they are protected by means of remote action, as it is known. The length of a composite 54 is determined by the size of the workstations in which the method steps C, D, E and F are carried out. However, it is entirely conceivable for the method steps A to F to be carried out continuously; this means that this composite is, as it were, "endless", since, when the last supporting element 12 belonging to the composite is cut off, at the same time a new first pair of spring rails is appended to it. In order to transfer the grid-like composite 54 from one treatment station to the next treatment station, it is advantageous if apertures 57 are made in the strips 44 - preferably in the region of the subsequent waste pieces 56. - but this half does not influence the requirements placed on the supporting element with regard to contact-pressure distribution and wiper-strip guidance. Therefore, its assembly time need not be considered either when defining the chronological sequence of the method steps belonging to the production method according to the invention. Assembling the device half 16 to the supporting elements 12 or to its individual elements - as an intermediate step, for example between the method steps B and C or C and D or D and E or E and F - does not change the method according to the invention of producing an advantageous supporting element in a particularly economic manner. A production method according to the invention is merely characterized by the fact that the prefabricated spring rails 26, 28 of a plurality of supporting elements 12 can be firmly connected to one another in pairs and aligned parallel to one another by means of at least one strip-like retaining element 44 aligned transversally with respect to the spring rails, and that the grid-like composite 54 obtained in this way is subjected to at least one further method step, after which the supporting elements 12 are detached from the composite 54 by separating the retaining element between the respective pairs of spring rails. After that, the wiper blade can be assembled and, in accordance with the schematic breakdown according to Figure 6, the assembly can comprise the further steps; G If necessary, fixing the wiper-blade-side half 16 of the said connecting direction [sic], H Pulling the resilient wiper strip 22 (Fig. 5) into the supporting element 12 which, in turn, has been produced by the extrusion process, for example, and then cut to length, graphited, etc, (H2), I Securing the wiper strip 22 in the supporting element 12 against longitudinal displacement and K Fitting protective coverings 60 to the wiper-blade ends - A device according to the invention for implementing the above-described method or the variants of the method substantially comprises the device components illustrated in Figure 6 and indicated in the description. WE CLAIM ; 1. Method of producing a strip-like, elongated springy element (12) for supporting a resilient wiper strip (22) of a windscreen wiper for vehicles, which has two spring rails (26, 28) that are located at a distance (24) from each other and substantially parallel to each other and which, at least at their two end sections, are firmly connected to each other by means of transverse webs (30) which are arranged on one strip surface (14) of the spring rails and bridge across the distance (24), characterized in that the prefabricated spring rails (26, 28) of a plurality of supporting elements (12) are firmly connected to one another in pairs and aligned substantially parallel to one another by means of at least one strip-like retaining element (44) which is aligned transversally with respect to the spring rails, in that the grid-like composite (54) obtained in this way is subjected to at least one method step, after which, by separating the retaining element (44) between the respective pairs of spring rails (26, 28), the supporting elements (12) are detached from the composite (54). 2. Method as claimed in claim 1, wherein a strip-like retaining element (44) is fixed to each of the two spring-rail end sections of the pairs of spring rails (26, 28). 3. Method as claimed in claim 2, wherein the two strip-like retaining elements (44) are provided with moulded sections (48) that are matched to the distances (50) between the associated pairs of spring rails (26, 28) and which extend like bridges from one (26, 28) to the other spring rail (26, 28) of a pair. 4. Method as claimed in any one of claims 1 to 3, wherein the grid-like composite (54) is subjected to heat treatment. 5. Method as claimed in claim 4, wherein the grid-like composite (54) is galvanized or provided with a coating containing zinc. 6. Method as claimed in any one of claims 4 or 5, wherein me grid-like composite (54) is painted. 7. Method as claimed in any one of claims 1 to 6, wherein a wiper-blade-side half (16) of a device for connecting the wiper blade to a wiper arm (18) is fixed to the associated pairs of spring rails (26, 28), 8. Method as claimed in any one of claims 1 to 7, wherein the retaining element is separated out from the composite (54) along the outer longitudinal edges of both spring rails (26, 28). 9. Method as claimed in any one of claims 1 to 8, wherein the spring rails (26, 28) are provided in their longitudinal extent with a curvature on whose outer side the strip¬ like retaining element (44) is fixed. 10. Method of producing a strip-like, elongated springy element for supporting a resilient wiper strip, substantially as hereinabove described and illustrated with reference to the accompanying drawings. Dated this 7 day of March 2002

Documents:

abs-in-pct-2002-355-che.jpg

in-pct-2002-355-che-abstract.pdf

in-pct-2002-355-che-claims filed.pdf

in-pct-2002-355-che-claims granted.pdf

in-pct-2002-355-che-correspondnece-others.pdf

in-pct-2002-355-che-correspondnece-po.pdf

in-pct-2002-355-che-description(complete)filed.pdf

in-pct-2002-355-che-description(complete)granted.pdf

in-pct-2002-355-che-drawings.pdf

in-pct-2002-355-che-form 1.pdf

in-pct-2002-355-che-form 18.pdf

in-pct-2002-355-che-form 26.pdf

in-pct-2002-355-che-form 3.pdf

in-pct-2002-355-che-form 5.pdf

in-pct-2002-355-che-other document.pdf

in-pct-2002-355-che-pct.pdf