MXPA97007036A

MXPA97007036A - Method for producing a blowed molded body that has multiple dimensions and a device to carry out the met

Info

Publication number: MXPA97007036A
Application number: MXPA/A/1997/007036A
Authority: MX
Inventors: Tietto Mario
Original assignee: St Soffiaggio Tecnica Srl; Tietto Mario
Priority date: 1995-03-13
Filing date: 1997-09-12
Publication date: 1998-07-03

Abstract

The present invention relates to a method for producing a blow molded tubular body having multiple dimensions with the following steps: a) extrusion of a tubular component that is enclosed at the front, with injection of gas into the tubular component, and coupling the tubular component with a shaping unit, b) deposition of the tubular component configured, in the plastic state, on a top-half mold half part, c) free descent of a part of the tubular component on a part of a mold half-level lower, located at a level that is lower than that of the upper mold half mold part, d) closure of the mold half and blow molding, the invention further relates to a device for producing a tubular body blow molding that has multiple dimensions, which includes: a shaping unit to shape the tubular component before its deposition on a half m olde, a nozzle for the injection of gas into the tubular component during extrusion, a conveyor device for transporting the tubular component during extrusion and allowing a coupling of the configured unit

Description

METHOD OF PRODUCING A BLOWED MOLDED BODY THAT HAS MULTIPLE DIMENSIONS AND A PIFRl DEVICE CARRYING THE METHOD DESCRIPTIVE MEMORY The present invention relates to a method for producing a blow molded body having multiple dimensions and to a device for carrying out the method. It is known that it is possible to blow-molding asymmetric parts that have a complicated shape, which have, for example, an axis that is first oriented in one dimension then in a second and finally in a third, thus creating multiple dimensions such as ducts forced ventilation of autoles. The simplest way to mold these parts is to extrude a very long tubular component whose diameter is sufficient to cover the entire profile of the part to be molded. In this case, obviously the molded part can have a diameter that is much smaller than the diameter of the tubular component from which it is obtained; consequently, waste is very high, up to 300-1000%. This implies serious problems, since the waste material must not only be ground again, mixed and cleaned, with obvious loads, but during all these treatments its quality degrades considerably, so it is required more than just virgin material for many productions, excluding recycled waste material. Moreover, in this way heat-sealed seams are necessarily formed along two opposite edges of the finished blow molded body which may be more or less satisfactory, depending on several molding parameters which are difficult to control and which depend particulate mind of the form of the mold, but in any case constitute a severe factor of weakness for the finished body. Finally, a machine that is many times larger than that required to mold a straight part of the same diameter is obviously necessary. In this way, the costs of the machine, material, consumption, electricity, etc., rise considerably. Battenfeld Fisher and Krupp Kautex have developed a system in which the extruded tubular component is placed inside a mold that can be disassembled by virtue of a series of robotic mechanical devices that are arranged to deform the tubular component, which is still in the plastic state, and adapt it to the shape of the mold. In this way, the waste problem is solved in principle, but a very expensive mold must be used. In particular, the modular mold is ex- tremely expensive because it is composed of several that must be gradually closed when the tubular component is bent by the mechanical devices to give it the desired shape. Placo Co. has developed a system in which the mold assembly is movable, for < That you can follow a predefined path that corresponds to the final shape of the array that will be produced. Obviously, in this case also, the movement of the mold assembly is complicated and very expensive. Moreover, in view of the huge le masses, problems of inertia arise that force the process to slow down. The slowness not only obviously limits productivity, but also produces intrinsic problems for this type of production. If the times are very long, the extruded tubular component deposited in the middle of the mold tends to cool before the blow molding, and also does not uniformly. This obviously causes problems, especially for the thin parts, which are subjected to rapid cooling. It must be considered in fact that the mold is cooled and made of metallic material; consequently, it is an excellent conductor of heat. In this way, during blow molding, the colder parts of the tubular component certainly can not have the same expansion capacity as the hotter parts, and therefore the colder parts will be maintained at relatively excessive thicknesses., while the hot parts will be subjected to a considerable stretch and a corresponding reduction in thickness that weakens the finished body. Moreover, it is quite difficult to obtain small radii of curvature. Finally, there are difficult problems to adjust the machine, on a case-by-case basis, to synchronize the speed of movement of the mold assembly with the downward velocity of the tubular component. IHI and Surnitomo have developed a machine in which the tubular component is extracted by suction in the mold, which is already closed. This system can only work under certain favorable conditions. Furthermore, precautions are necessary to prevent the tubular component from adhering to the mold walls during insertion. German patent application DE 4 305 735.7 describes a system in which, simultaneously with the extrusion, a mobile frame lifts the tubular component in the desired shape; then the frame is transferred to the closing region and is opened, depositing the tubular component in a mold half. However, to achieve this procedure it is necessary to synchronize the movement of the frame with the downward velocity of the tube. This requires the intervention of specialized personnel each time a different part must be molded. All this implies problems that are not easy to solve. Moreover, the tubular component must follow a mixing curve, because the extrusion head is vertical. This curve must be taken into account during programming. Moreover, it is quite difficult to obtain small radii of curvature. Therefore, the purpose of the present invention is to overcome the above disadvantages by providing a method and a device that allows molding parts that have and is multiple with an apparatus that is simple and inexpensive. One object is to avoid the use of sophisticated electronic controls. Another object is to be able to mold parts of any length without problems. Another object is to move only parts that have limited weights and dimensions, to ensure a high speed as well as a limited cost. Another object is to allow a low conversion cost as long as the mold has to be changed. Another object is to obtain small radii of curvature even with highly rigid tubes. Another object is to be able to use all existing conventional blow molding molds without the need for particular adaptations. This purpose, these objects and others are achieved by the method according to the invention, which includes the following steps: a) extrusion of a tubular component that is closed at the front, with gas injection into the tubular component, and the coupling of the tubular component with a shaping unit, b) deposition of the shaped tubular component, in the plastic state, in a top-half mold half part; c) free descent of a part of the tubular component onto a lower mold half part, located at the level that is lower than that of the upper level mold half part; d) closure of the mold half and blow molding. The invention further relates to a device for producing a blow molded tubular body having multiple dimensions including: a shaping unit for configuring the tubular component before deposition on a mold half; a nozzle for injecting gas into the tubular component during an extrusion; a conveyor device for transporting the tubular component during extrusion and allowing a coupling of the shaping unit. The invention will become apparent with reference to the accompanying drawings, provided by way of non-limiting example, of the multiple modalities of the method and of the device according to the invention, wherein: Figure 1 is a plan view of a first embodiment of the invention; Figure 2 is a schematic front view of the device of Figure 1; Figure 3 is a front view of the device of Figure 1 during another stage of the method; Figure 4 is a plan view of the device of Figure 3; Figure 5 is a partially sectional front view of the device of Figure 3 in a subsequent stage of the. method; Figure 5 is a partially sectional front view of the device of Figure 5 in a subsequent step of the method; Figure 7 is a perspective view of the device of Figure 6 in a subsequent step of the method; Figure 8 is a partially sectional front view of the device of Figure 7 in a subsequent step of the method; Figure 9 is a plan view of a second embodiment of the device according to the invention; Fig. 10 is a plan view of the device of Fig. 9 in a next step of the method; Figure 11 is a plan view of the device of Figure 10 in a subsequent stage of the method; Figure 12 is a plan view of a third embodiment of the device according to the invention; Figure 13 is a view of the device of Figure 12 in a subsequent step of the method; Figure 14 is a plan view of a fourth embodiment of the device according to the invention; Figure 15 is a front view of a detail of the device of Figure 1.4; Figure 16 is a plan view of a fifth embodiment of the device according to the invention; Figure 17 is a partially sectional front view of a detail of the device in Figure 16; Fig. 1 (3 is a plan view of a sixth embodiment of the device according to the invention: Fig. 19 is a front view of a detail of the device of Fig. 18. Fig. 20 is a partially sectional front view of a Fig. 21 is a plan view of a seventh embodiment of the device according to the invention; Fig. 22 is a plan view of the arrangement of Fig. 21; in a subsequent step of the method: Figure 23 is a front view of a detail of the device of Figure 21; Figure 24 is a plan view of the device of Figure 22 in a subsequent step of the method; and Figure 25 is a front view of a detail of the device in Figure 24. Figure 26 is another embodiment of the device to Figure 5. Figure 27 is another embodiment of the device to Figures 5 and 6; Figure 28 is another embodiment of the device; e Figure 6; Figure 29 is another embodiment of the device of Figure 8. With reference to Figures 1 to 8, a first embodiment of the method and device according to the invention is shown. In particular, in step (a), the tubular component 10 is closed in the front, at the end 11, to prevent gas leakage, usually air, which is injected into the tubular component to keep its walls mutually apart. The tubular component is in fact still in the plastic state and any contact between the walls would lead to immediate mutual adhesion. At the end of the extrusion, the tubular component 10 is cut and sealed by the sewing and cutting pliers 24. The tubular component 10 is coupled by a shaping unit 12 and 13, which engages the tubular component moving in the direction indicated by the arrows 14. In particular, the two parts 12 and 13 of the shaping unit can each be moved by at least one drive cylinder 16 and 17. According to step (b), the tubular component 10, supported by the shaping unit 12 and 13 (which can also be heated) is still at a high temperature and in the plastic state, and is deposited in a top half mold half part 15. The mold half can be composed of several parts which they are identified according to their distance (elevation) from the ground for the purposes of the present invention. The upper level mold half part 15, in particular, is at a higher level than a lower level mold half part 18 located at a lower level. Step (b) is described with particular reference to figures 5, 6 and 7. According to step (c), the tubular componentJH. , still in the plastic state, now free from engagement with the config unit? Radora 12 and 13, is placed on the part of half high mold 15 has a projecting portion 19, shown in dashed lines, that descends freely by gravity on the lower mold half part 18, in the direction of the arrow 9, until it reaches the position shown in dotted and dashed lines. Step (c) is described with particular reference to Figure 7. According to step (d), with particular reference to Figure 8, the upper part of the mold 20 is closed and the tubular component is blow molded, inserting a needle, until the mold cavity is completely filled. The unit configures time 12 and 13 acts mainly in two dimensions, on a substantially horizontal plane. In free descent of a part 19 of the tubular component 10 occurs in a substantially vertical third dimension. The device according to the invention includes: a configurator unit 12 and 13 for configuring the tubular component before its deposition on a mold half; a nozzle 21 for introducing gas into the tubular component 10 during an extrusion; and a conveyor device 22 for conveying the tubular component 10 during extrusion and allowing engagement of the shaping unit 12 and 13. The shaping unit 12, 13 is actuated by parts that can move in a horizontal direction substancialrnente 12 and 13. The unit framer 12 and 13 is formed by two complementary bodies 12 and 13 loe opposite sides of the tubular component 10. engage the conveyor device 22 acts substancialmen and in a horizontal direction, and according to the embodiment shown in figures 1 to 4, It is formed by a conveyor belt that preferably works on a horizontal plane. The mold half 15, 18 is preferably arranged below the extrusion region, so that it is not necessary to move the tubular component 10 horizontally. Preferably, the extrusion head 23 is disposed hopzontally, to be able to carry out a horizontal extrusion, so that the tubular component 10 is immediately in the position that is suitable for depositing it on the mold half. The above-described embodiment is preferred because it is particularly simple and reliable both in terms of equipment and in terms of execution of the method. Preferably, with particular reference to Figs. 26-29, the shaping unit 12, 13 includes two parts 40, 41, 42, 43 that allow relative movement of one relative to the other. In particular, a lateral part 40, 42 laterally supports the tubular component 1.0 and is in turn supported by an actuator device 16, 17. A lower part 41, 43 supports in a downward region, the tubular component 10. The lower part 41, 43 can be moved with respect to the lateral part 40, 42 by virtue of the auxiliary actuator device 40, 42, which is formed for example by a pair of pneumatic cylinders 44, 45. This mode is preferred because it reduces the possibility of adhesion between the tubular component and the configurator unit 12, 13, thus offering the best operational reliability. Figures 26-29 further illustrate, in succession, the development of relative movement of the lateral part and the lower part, to allow an adequate positioning of the tubular component in the lower mold half 15, 18. According to another embodiment, with particular reference to figures 9 to 10, the conveyor device 25 is formed by a fastener pull that is arranged outside the tubular component 10. in this case, the shaping unit 12, 13 can even be closed before the engagement of the conveyor device 25, as shown in the figures. However, to reduce friction and particularly for complicated shapes, it is preferable to first activate the conveyor device 25 and then the configurator unit 12, 13.

More generally, according to the invention, it is preferable to first extrude the tubular component completely, without configuring it during extrusion, and then, once the extrusion has concluded, to shape it and finally to transfer it into the mold. With an alternative, with a modality that is not shown in the figures but which is understandable by a technician in the field, the conveyor device is formed by a push bar that is disposed within the tubular component. In particular, the push rod is disposed inside the extrusion head 23 and can push the tubular component forward while it is at the outset. According to this last embodiment, the tubular component can be extruded only when it is straight and the shaping unit 12 and 13 can couple the tubular component only at the end of the extrusion. According to another embodiment, described with particular reference to FIGS. 12 and 13, the shaping unit is formed by multiple parallel mobile bodies 26, whose profile can be altered by coupling with a template 27. This embodiment has the advantage of allowing the rapid and low-cost variation of the profile, simply by changing the template 27. According to another embodiment, illustrated with particular reference to Figures 14-17, the unit with igurator is formed by multiple motorized rollers 28 and 29 having vertical axes. In this case also, the forming unit is formed by two complementary parts 30 and 31, 32 and 33, which are separated when the configured tubular component is exactly on the mold, thus depositing it on the mold half 15, as shown in particular Figure 17. According to another embodiment, described with particular reference to Figures 18-20, the shaping unit is formed by multiple motorized rollers 34 having a horizontal axis. In this case, the tubular component 10 configured on the rollers 34 is lifted by multiple fasteners 35 that can carry it and deposit it on the mold half part 15. According to another embodiment, described with particular reference to Figures 21-25, the shaping unit is formed by a device for moving the web 22 in a direction 36 that is substantially perpendicular to a direction 37 for extrusion and / or advancement of the tubular component. The device for movement in the direction 36 is not shown in the figures but can be provided for example by mounting the band on a pair of frames that are arranged in the direction 36 and moving the frames with a hydraulic motor by a degree corresponding to the fold required for the tubular component 10. In this way, movement and extrusion can occur simultaneously and it is thus possible to form the required profile of the tubular component 10. The rollers 39 keep the tubular component -10 positioned precisely, so that he can follow the movements of the band. Once it has been configured, the tubular component 10 can be lifted with the fasteners 38 and deposited on the mold half 15, as already described with reference to Figure 20. The invention lends itself, as shown, to many. variations, all of which are within the scope of the same inventive concept. Accordingly, it is possible to mutually combine parts of these variations or replace them with other equivalent means for the purposes of the invention. In this way, for example, the actuator device 16, 17 can be formed by spherical screws, by articulated systems or by serrated bands, instead of the piston and cylinder units shown in the figures. In particular, it has been observed that the toothed bands are particularly preferred because of their higher speed, because they do not make noise and have the ability to control.

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A method for producing a tubular body blow molded having multiple dimensions, which comprises the following steps: a) a complete extrusion of a tubular component (10) that is enclosed in the front (11), with gas injection inside, said tubular component-, b) subsequently, after said extrusion has been completed, the coupling of said tubular component with a shaping unit (12, 13), said coupling forming said tubular element, c) the deposition of said configured tubular component (10), in a plastic state, on a mold half (15), d) closure of said mold half and blow molding.

2. The method according to claim 1, wherein said shaping unit acts mainly in two dimensions, on a substantially horizontal plane, said method comprises a free descent of the part of said tubular component (10) in a third dimension substantially vertical (9).

3. The method according to at least one of the preceding claims, wherein, during said extrusion, said tubular component (10) is coupled with a conveyor device (22) that preferably operates in a horizontal direction.

4. The method according to claim 3, wherein said conveyor device is formed by a t-band sporting (22) preferably acting on a horizontal plane.

5. The method of compliance with at least one of the preceding claims, wherein said conveyor device is formed by a pull fastener (25) that is arranged outside said tubular component.

6. The method according to at least one of the preceding claims, wherein said conveyor device is formed by a push rod that is disposed inside said tubular component.

7. The method according to at least one of the preceding claims, wherein said configurator unit is formed by two complementary bodies (12, 13) that couple the opposite sides of said tubular component (10)

8. The method according to at least one of the preceding claims, wherein said configurator unit is formed by multiple movable parallel bodies (26) whose profile can be changed using a template (27).

9. The method according to at least one of the preceding claims, wherein an extrusion head (23) is arranged horizontally, to perform a horizontal extrusion.

10. The method according to at least one of the preceding claims, wherein said mold half (15, 18) is substantially disposed below an extrusion region. 1.1.- A device for producing a tubular body blow molded having multiple dimensions, comprising: a shaping unit (12, 13) to give shape to said tubular component (10) before its deposition on a mold half (15) , 18); a nozzle (21) for gas injection into said tubular component (10) during an extrusion; a conveyor device (22) for transporting said tubular component during said extrusion and allowing a coupling of said configurator unit (12, 13); said configurator unit comprises two parts (40, 41, 42, 43) that allow a relative movement of one relative to the other, said relative movement forming said tubular component; said conveyor device is different and is provided with independent movement with respect to said configurator unit. 12. The device according to claim 11, wherein said configurator unit (12, 13) is driven by devices that can be moved in a substantially horizontal direction. 13. ™ A device according to at least one of the preceding claims, wherein said conveyor device (22) acts substantially in a horizontal direction 1. 14. A device according to at least one of the preceding claims, wherein said conveyor device (22) is formed by a band. conveyor that preferably operates on a horizontal plane. 15. A device according to at least one of the preceding claims, wherein said conveyor device is formed by a pull fastener (25) that is disposed outside said tubular component. 16. A device according to at least one of the preceding claims, wherein said conveyor device is formed by a push rod that is placed inside said tubular component. 17. A device according to at least one of the preceding claims, wherein said unit forms (12, 13) is formed by two complementary bodies (12, 13) coupling the opposite sides of said tubular component ( 10). 18. A device according to at least one of the preceding claims, wherein said configurator unit is formed by multiple movable parallel bodies (26) whose profile can be changed by coupling a template (27). 19. A device according to at least one of the preceding claims, in which an extrusion head (23) is arranged horizontally, to carry out a horizontal extrusion »20.- A device in compliance with at least one one of the preceding claims, wherein said mold half (15, 18) is disposed below an extrusion region 21. A device according to at least one of the preceding claims, wherein said two parts comprise a side part (40, 42) and a bottom part (41, 43). 22. A device according to at least one of the preceding claims, wherein a direction of movement of said shaping unit is substantially perpendicular to a conveying direction of said conveying device.