Molding member and method of producing it

Abstract: A drip molding member (3) for an automobile side window or the like having portions (3a,3b,3c) of differing cross-section, and a method of manufacturing it. The member is formed by extruding a length of constant cross-section and selectively removing material to form the sections of different cross-section. The variation in cross-section allows a weir or gutter to be formed along the side of the window but not the top.

Description: The present invention relates to a drip molding member for automobiles, formed at least partly of a synthetic resin material, and a method of producing a drip molding member for automobiles. An automobile employs various kinds of elongate molding members formed at least partly of a synthetic resin material, such as drip molding members, front and rear window molding members, etc. Of these, the drip molding member extends along the front pillar and the side edge of the roof panel of the vehicle body, while front and rear window molding members extend respectively along the periphery of the front and rear window plates, i.e. along the front and rear pillars and the front and rear edges of the roof panel. A variety of requirements are imposed on the molding members, mainly from design and/or functional viewpoint, and resulted in an increased demand in the automobile industry for the molding members whose cross-sectional shape varies in the longitudinal direction. More particularly, one proposal is directed to a window molding member having side portions with a first predetermined cross-sectional shape, an upper portion with a second predetermined cross-sectional shape, and corner portions arranged between the side and upper portions, where the cross-sectional shape changes gradually from the first to the second. Another proposal is directed to a drip molding member composed of a core element in the form of a metal strip which has been shaped into the desired cross-sectional shape, as well as upper and lower lip elements of synthetic resin material which are integral with the core element and molded such that the core element is partly exposed to, and visible from outside as a longitudinally extending ornamental portion with a metallic luster. The lower lip element is of a cross-sectional shape that is substantially constant throughout the entire length, while the upper lip element has a pillar portion with a relatively wide first cross-sectional shape, a roof portion with a relatively narrow second cross-sectional shape, and a corner portion between the pillar and roof portions, where the cross-sectional shape changes gradually from the first to the second. To produce elongate molding members whose cross-sectional shape varies in the longitudinal direction, it has been a conventional practice to use a process which includes preparation of the core element by shaping the raw metal strip into the desired cross-sectional shape with a roll forming machine, press machine, etc., placing each core element in the mold of an injection molding machine, and subsequently molding the synthetic resin material into the desired configuration. With such a process, however, since the entire core element of the elongate molding member has to be completely accommodated in the mold, the molding machine as a whole becomes very bulky and requires a substantial space in the factory. Moreover, the process involves relatively complex steps with which the molding members can be produced only one by one, and it is thus difficult to improve the productivity. Another possibility for the production of such molding members is to physically divide each molding member into first and second extruded portions with the respectively predetermined cross-sectional shapes, which are connected with each other either by an injection molding process or by using a separate connection piece. However, connection of the two portions by means of the injection molding accompanies formation of undesirable burrs along the junctions and resultant deterioration in the appearance, while use of the separate connection piece results in the increased number of the required components and assembly steps. GB 2126151 shows a process in which a molding member having a lip portion is cut in a predetermined pattern by engagement with a cutter movable laterally to the member. EP 0 118 397 shows a device for extruding a molding member with a lip portion. This lip is deflected immediately following the extrusion step, selectively and permanently from its extruded shape. According to the present invention, there is provided a drip molding member for automobiles, comprising a pillar portion to extend along a pillar of an automobile body, a roof portion to extend along a side edge of a roof panel of the automobile body, and a corner portion integrally and continuously connecting said pillar portion and said roof portion with each other, said molding member having at least one lip section composed of a synthetic resin material, and a core element composed of a profiled metal and integrated with, and arranged at least partly in said lip section, said molding member being bent substantially at said corner portion, wherein said lip section has a first width along said pillar portion, a second width along said roof portion which is different from said first width, and a third width along said corner portion in which the first width gradually changes to the second width, characterised in that said moulding member is formed by coextrusion of said lip section and said core element and a narrower one of said first width and said second width is defined by removal of a controlled amount of the synthetic resin material from a predetermined location corresponding to said lip section. The present invention also provides a method of producing a drip molding member for automobiles, said molding member comprising a pillar portion to extend along the pillar of the automobile body, a roof portion to extend along a side edge of a roof panel of the automobile body, and a corner portion integrally and continuously connecting said pillar portion and said roof portion with each other, said molding member having at least one lip section composed of a synthetic resin material, and a core element composed of a profiled metal and integrated with, and arranged at least partly in said lip section, wherein said method comprises the steps of: supplying a profiled metal strip to an extrusion die as the core element; extruding an elongate continuous body with a cross-section which is substantially constant in its longitudinal direction, said continuous body corresponding in cross- section to said molding member at its portion which corresponds to a wider one of said first width and said second width, the elongate continuous body including the core element; removing a controlled amount of the extruded synthetic resin material from a predetermined location of said continuous body corresponding to said narrower one of said first width and said second width by moving a cutter member in a controlled manner relative to the continuous body in accordance with an extrusion length of the continuous body; and cutting said continuous body into a predetermined length of the molding member, either before or after said removing step. The present invention will be further described hereinafter, with reference to the following description of exemplary embodiments and the accompanying drawings, in which:- Figure 1 is a perspective view of an automobile with molding members according to the present invention; Figure 2 is a side view of a drip molding member according to the invention shown in Figure 1; Figure 3 is a fragmentary perspective view, in an enlarged scale, of the drip molding member shown in Figure 2; Figure 4 is a system diagram of the production line which is adapted to produce various molding members; Figure 5 is a side view of the first cutting station as shown in Figure 4; Figure 6 is a sectional view taken substantially along the line A-A in Figure 5; Figure 7 is a diagram showing the relation between the displacement of the cutter member and the supplied length of the core element; Figures 8 and 9 show modifications of the cutting members; and Figure 10 shows another modified example which is further provided with a reforming roller behind the cutter member. There is shown in Figure 1 an automobile designated as a whole by reference numeral 1, which is provided with various kinds of elongated molding members composed at least partly of a suitable synthetic resin material. These molding members include, among others, a front window molding member 2, a drip molding member 3, etc. The drip molding member 3 is arranged along the front pillar and the side edge of the roof panel of the automobile, and includes a pillar portion 3a of a length L₁, a corner portion 3b of a length L₂ and a roof portion 3c of a length L₃. The drip molding member 3 is composed of a core element 4 having an ornamental outer surface 5 with a metallic luster, and upper and lower lip elements 6, 7 which are arranged along the upper and lower edges of the core element 4, respectively, in such a manner that the ornamental outer surface 5 of the core element 4 is exposed outside between the lip elements 6, 7. The core element 4 is formed of a metal strip, such as a stainless steel strip, shaped into a desired cross-section which is substantially constant throughout the entire length of the drip molding member 3. The upper and lower lip elements 6, 7 are formed of suitable synthetic resin material which has been co-extruded about the core element 4. The lower lip element 7 has a cross-section which is substantially constant throughout the entire length of the drip molding member 3, while the upper lip element 6 has a cross-section which varies in the longitudinal direction of the molding member 3. More particularly, the upper lip element 6 has a relatively wide and substantially constant cross-section along the pillar portion 3a, a relatively narrow and substantially constant cross-section along the roof portion 3c, and a transitional cross-section along the corner portion 3b between the pillar and roof portions 3a, 3c in which the wide section changes gradually to the narrow section. The above-mentioned molding members 2, 3 can be produced in the manner to be described hereinafter. The following description will be made with reference to the production of the drip molding member 3. There is shown in Fig. 4 a system diagram of the production line. The production line includes an uncoiler 11 from which a metal strip 12 is continuously supplied by a pair of pinch rollers 13. Another roller 14 serves to continuously supply a protective tape 15 which is separably adhered, by means of a pair of adhesion rollers 16, onto that portion of the metal strip 12 which eventually forms the ornamental portions 5 of the molding member 3 with the desired metallic luster, and which has thus to be protected by the tape 15. The metal strip 12 applied with the protective tape 15 forms a composite body 17 which, subsequently, is subjected to surface degreasing and cleaning at a cleaning station 18 for carrying out a sanding or the like treatment, is coated with an adhesive material at a roll coating station 19, and is subjected to baking at the baking station 20. The composite body 17 is further passed through and cooled in a cooling tank 21, and is then shaped into a desired, longitudinally constant cross-section at a roll forming machine 22 to form a continuous core element 4 of the molding member 3. The core element 4 so obtained is supplied to a measuring station 23 which includes a rotary encoder or the like detector for measuring the supplied length of the core element 4, and then to an extrusion die 24 which is further supplied with a suitable synthetic resin material in its heated molten state. The molten synthetic resin material is co-extruded from the extrusion die 24 as a continuous extruded body 25 in which the upper and lower lip elements 6, 7 are made integral with the core element 4, whereby the extruded body 25 has a substantially constant cross-section which corresponds to that of the pillar portion 3a of the molding member 3. To produce molding members with a longitudinally variable cross-section, in accordance with the illustrated preferred embodiment of the present invention, the extruded body 25 as extruded from the extrusion die 24 is further subjected to the removal of a controlled amount of synthetic resin material from the predetermined location of the upper lip element 6. To this end, there is provided a controller 26 which is adapted to receive from the measuring station 23 a signal representing the supplied length of the core element 4, while a first cutting station 27 is arranged on the exit or discharge side of the die 24 and is adapted to be controlled by the controller 26 according to the supplied length of the core element 4. The extruded body 25 is subsequently passed through a cooling tank 28 where it is cooled, and is then advanced by a take-up device 29 and cut into the predetermined length of the product at a second cutting station 30 which, too, is controlled by the controller 26 according to the supplied length of the core element 4. As particularly shown in Figs. 5 and 6, the first cutting station 27 includes a support table 31 arranged adjacent to, and on the discharge side of, the extrusion die 24 for supporting the extruded body 25 as it is extruded from the die 24, a rotatable cutter blade 32 biased toward the support table 31 by means of a compression coil spring 33, as well as a slider member 34 for mounting the cutter blade 32 which member is movable in a direction that extends in parallel with the rotational axis of the cutter blade 32. The slider member 34, per se, is supported by a threaded drive shaft 35 and a stationary guide rod 36 which is fixedly secured to a pair of brackets 37, 38. The drive shaft 35 is rotatably journalled by the brackets 37, 38, is in mesh with the slider member 34, and is connected to a reversible servomotor 39 which is adapted to be controlled by the controller 26. Thus, by actuating the servomotor 39 in the normal or reverse direction, the cutter blade 32 is caused to move in the desired axial direction M or N both indicated by double arrow in Fig. 6, in accordance with the length of the core element 4 supplied to the extrusion die 24. Fig. 7 shows the relation between the length of the core element 4 which has been supplied to the extrusion die 24 and the displacement of the cutter member 32, during the production of the drip molding member 3 explained above with reference to Figs. 2 and 3. For the period in which the extrusion die 24 discharges that portion of the extruded body 25 which corresponds to the pillar portion 3a of the molding member 3 with the length L₁, co-extrusion of the synthetic resin material with the core element 4 is carried out with the cutter member 32 maintained at an extreme position in the axial direction M, after the servomotor 39 has been actuated in the normal direction. In this extreme position, the cutter member 32 is spaced from the upper lip element 6 of the molding member 3. As the detector of the measuring station 23 detects the completion of the supply of twice the length L₁ of the core element 4, or the beginning point of the corner portion 3b of the length L₂, the controller 26 supplies a command signal to the servomotor 39. By this the servomotor 39 is actuated in the reverse direction, causing the cutter member 32 to move in the axial direction N. During this movement, the cutter member 32 comes into contact with the upper lip portion 6. As the cutter member 32 is further moved toward another extreme position in the axial direction N, until completion of the supply of length L₂ of the core element 4, the cutter member 32 removes a desired part 6a of the synthetic resin material of the upper lip element 6 with a gradually increasing width. When the detector at the measuring station 23 detects the beginning point of the roof portion 3c of the drip molding member 3 with the length L₃, the servomotor 39 is stopped so that the cutter member 32 is maintained in its extreme position in which the removal of the synthetic resin material is carried out with the maximum width. The cutter member 32 is maintained in this extreme position until the detector of the measuring station 23 detects completion of the supply of twice the length L₃ of the core element 4. At such occasion, the controller 26 supplies a command signal to the servomotor 39 to actuate the latter in the normal direction. By this, the cutter member 32 is caused to move in the axial direction M, removing the synthetic resin material from the upper lip element 6 with a gradually decreasing width until the detector of the measuring station 23 detects completion of the supply of the length L₂ of the core element 4. Subsequently, the cutter member 32 is disengaged from the lip element 6 and is returned to its initial extreme position in the axial direction M. The cutter member 32 is maintained in this position for a new cycle of operation. Preferably, the removal of the synthetic resin material is carried out while the extruded body 25 is still hot and soft. The extruded body 25 subjected to the removal of the synthetic resin material at the first cutting station 27 is then supplied to the second cutting station 30 where it is cut into the predetermined length of the desired molding member 3 at predetermined positions of the extruded body 25 which correspond to the centers of the length 2L₁ and 2L₃, respectively. Furthermore, by repeating the above-mentioned operations, the molding members can be continuously produced one by one, in an efficient and reliable manner. Figs. 8 through 10 show various modified versions of the first cutting station 27, the particulars of which will be briefly explained below. The version shown in Fig. 8 features an arrangement wherein the cutter member 32 is formed of a cutter plate with a sharp edge, which is disposed on the discharge end wall of the extrusion die 24 and is movable in the directions P and Q, both indicated by double arrow, so as to provide a longitudinally variable width of that part 6a of the synthetic resin material of the upper lip element 6, which is to be removed in accordance with the length of the core element 4 supplied to the extrusion die 24. The version shown in Fig. 9 features an arrangement wherein the cutter member 32 is formed of a plate which is movable in the directions R and S both indicated by double arrow. The cutter blade 32 is so shaped as to define an arcuate blade portion, whereby the cut section of the upper lip element 6 becomes partly arcuate when longitudinally variable amount of the synthetic resin material is removed in accordance with the length of the core element 4 supplied to the extrusion die 24. The versions shown in Fig. 10 includes a reforming roller 40 arranged behind the cutter member 32, which roller is formed with a circumferentially extending reforming groove 41. The reforming roller 40 may be combined with any of the above-mentioned cutter members 32, and serves to effectively reform the surface of the molding member 2, 3 with undesirable sharp edges or uneven cut sections, which have been formed as a result of the cutting operation or removal of the synthetic resin material by means of the cutter member 32. To this end, the reforming roller 40 is adapted to be moved in the directions T and U, both indicated by double arrow, synchronously with the movement of the cutter member 32 in the axial directions M and N, P and Q, or R and S. The versions thus far described have been directed to an arrangement wherein the removal of the synthetic resin material from the upper lip element 6 of the drip molding member 3 is effected with respect to the corner and roof portions 3b, 3c, only. It is, however, possible to remove the material with a relatively small width from the lip element 6 along the pillar portion 3a of the molding member 3 as well. Also, the cutter member 32 and/or the second cutting station may effect the respective cutting operation in accordance with the length of the extruded body 25, instead of the supplied length of the core element 4. This is particularly effective for a molding member without the core element.

Claims: A drip molding member (3) for automobiles, comprising a pillar portion (3a) to extend along a pillar of an automobile body, a roof portion (3c) to extend along a side edge of a roof panel of the automobile body, and a corner portion (3b) integrally and continuously connecting said pillar portion (3a) and said roof portion (3c) with each other, said molding member (3) having at least one lip section (6,7) composed of a synthetic resin material, and a core element (4) composed of a profiled metal and integrated with, and arranged at least partly in said lip section (6,7), said molding member (3) being bent substantially at said corner portion (3b), wherein said lip section (6,7) has a first width along said pillar portion (3a), a second width along said roof portion (3c) which is different from said first width, and a third width along said corner portion (3b) in which the first width gradually changes to the second width, characterised in that said moulding member (3) is formed by co-extrusion of said lip section (6,7) and said core element (4) and a narrower one of said first width and said second width is defined by removal of a controlled amount of the synthetic resin material from a predetermined location corresponding to said lip section (6,7). The drip molding member as claimed in claim 1, wherein said core element (4) is partly exposed from said lip section (6,7). A method of producing a drip molding member for automobiles, said molding member (3) comprising a pillar portion (3a) to extend along the pillar of the automobile body, a roof portion (3c) to extend along a side edge of a roof panel of the automobile body, and a corner portion (3b) integrally and continuously connecting said pillar portion (3a) and said roof portion (3c) with each other, said molding member (3) having at least one lip section (6,7) composed of a synthetic resin material, and a core element (4) composed of a profiled metal and integrated with, and arranged at least partly in said lip section (6,7), wherein said method comprises the steps of: supplying a profiled metal strip to an extrusion die as the core element (4); extruding an elongate continuous body (25) with a cross-section which is substantially constant in its longitudinal direction, said continuous body (25) corresponding in cross-section to said molding member (3) at its portion (3a) which corresponds to a wider one of said first width and said second width, the elongate continuous body (25) including the core element (4); removing a controlled amount of the extruded synthetic resin material from a predetermined location of said continuous body (25) corresponding to said narrower one of said first width and said second width by moving a cutter member (32) in a controlled manner relative to the continuous body (25) in accordance with an extrusion length of the continuous body (25); and cutting said continuous body (25) into a predetermined length of the molding member (3), either before or after said removing step. The method as claimed in claim 3, wherein said molding member (3) is bent substantially at said corner portion (3b), further comprising the step of bending the continuous body (25) at a location which corresponds substantially to said corner portion (3b) of the molding member (3). The method as claimed in claim 3 or 4, wherein said controlled amount of the synthetic resin material is removed from said continuous body (25) immediately after the extrusion of the continuous body (25).

Inventors: IGARASHI NOBUO OBAYASHI-SHATAK, KONNO SADAO C O HASHIMOTO FORM, NAKAJIMA HIROYUKI C O HASHIMOT, TAMURA TATSUYA C O HASHIMOTO F, IGARASHI, NOBUO, OBAYASHI-SHATAKU NO. 4-413, KONNO, SADAO, C/O HASHIMOTO FORMING IND. CO.LTD, NAKAJIMA, HIROYUKI, C/O HASHIMOTO FORM. IND.CO.LTD, TAMURA, TATSUYA, C/O HASHIMOTO FORMING IND. CO.LTD
Applicants: HASHIMOTO FORMING KOGYO CO, HASHIMOTO FORMING INDUSTRY CO LTD
Application year: 1988
Main classification: B60R13
IPC codes: B29C47, B60R13, B60J10, B29C67, B60J1, B29C69, B26D1, B26D3