PROCESS AND SYSTEM FOR MANUFACTURING PRODUCTS CAST WITH POLYURETHANE AND HAVING A CONSTANT CROSS-SECTION

Abstract

A process and system for manufacturing polyurethane products having a continuous section includes placing and fastening multiple injection molds (3) on which is acting, at least, a force in axial direction and, optionally another in radial direction. During the process, the opening is avoided during the polyurethane foaming; injection of the polyurethane in a mold or molds (3), tilted or in vertical on a bench (4) to accumulate CO.sub.2 bubbles, at the top part during the polyurethane foaming; waiting for the polyurethane be expanded and withdrawing the mold (3) from the bench (4). The system includes: a feeder (1) of polyurethane; injection system or machine (2) in line, at least, a mold (3) and a bench (4) for placing and fastening the molds (3) located tilted or in vertical.

Claims

1. A process for manufacturing polyurethane cast products having a continuous section, characterized in that it comprises: placing and fastening one or more injection molds (3) on a bench (4) that avoid the mold opening during the polyurethane foaming, where the molds (3) are manufactured by extrusion without any further modification or adaptation, said molds (3) thus having a fixed cross-sectional profile with open ends, closing the ends of the mold (3) while allowing polyurethane injection through one end of the mold (3), polyurethane injection through said one end of the mold or molds (3), arranged tilted or in vertical on a bench (4), to accumulate the possible formation of holes and cavities provoked by CO.sub.2 bubbles, only at the top part of the mold (3) during the polyurethane foaming process, waiting for the polyurethane to be expanded, and a step of withdrawing the mold (3) from the bench (4).

2. The process for manufacturing polyurethane cast products having a continuous section according to claim 1, further comprising an intermediate step to carry out a change of the mold (3) tilt during the step in which the mold is on the bench.

3. The process for manufacturing polyurethane cast products having a continuous section according to claim 1 wherein, the polyurethane injection in the mold or molds (3) arranged tilted or in vertical, the said injection of product is carried out by the open top end of the mold (3) that serves for the material inlet and as air outlet (16) which occurs at same time.

4. The process for manufacturing polyurethane cast products having a continuous section according to claim 1 wherein, in the step of the polyurethane injection in the mold or molds (3), arranged tilted or in vertical, the said product injection is carried out by the open lower end of the mold (3) in which case the existence of an air outlet (16) is contemplated at the top end of the mold (3).

5. The process for manufacturing polyurethane cast products having a continuous section according to claim 1, wherein the polyurethane injection in the mold or molds (3) arranged tilted or in vertical is carried out by means of a manual process with the molds (3) arranged fixed directly on the bench (4).

6. The process for manufacturing polyurethane cast products having a continuous section according to claim 1, wherein the polyurethane injection in the mold or molds (3) arranged tilted or in vertical is carried out by means of a process in line, continuous or half continuous, in which case the bench (4) includes moving means where the molds are being positioned so that the injection is multiple and in line.

7. A system for manufacturing cast products of polyurethane having a constant section, characterized in that it comprises: a feeder (1) of polyurethane product; an injection system or machine (2) in line, that injects the product in its liquid or fluid form within the molds (3); at least, a mold (3) having the shape of the parts to be manufactured, where the molds (3) are manufactured by extrusion without any further modification or adaptation, said molds (3) thus having a fixed cross-sectional profile with open ends; a closing and joining system (11) that closes the ends of the molds (3) and, when the molds (3) are made by two parts (a, b), joins said two parts (a, b) together; and a bench (4) for placing and fastening the molds (3) located tilted or in vertical.

8. The system for manufacturing cast products of polyurethane having a constant section according to claim 7, wherein the closing and joining system (11) comprises a lower lid (18) for closing the lower end of the mold (3) and an axial pressure element (19) closing the top end of the mold (3).

9. The system for manufacturing cast products of polyurethane having a constant section according to claim 8, where the axial pressure element (19) is formed by rollers integrated on a top closing band (24).

10. The system for manufacturing cast products of polyurethane having a constant section according to claim 8, wherein the closing and joining system (11) is an independent module of the bench (4) further comprising girths or clamps (3) joining the mold parts (a, b) together when the polyurethane foams and pressure is exerted from inside.

11. The system for manufacturing cast products of polyurethane having a constant section according to claim 8, wherein the bench (4) includes moving means, such as a conveyor belt (22) on which the molds (3) are moving, to be passing in line under the product injection system or machine (2).

12. The system for manufacturing cast products of polyurethane having a constant section according to claim 11, further comprising stabilizing guides (23) that fasten the molds (3).

13. The system for manufacturing cast products of polyurethane having a constant section according to claim 7, which is an automated system that administers all the subsystems in a synchronized manner to carry out an automated serial production.

14. The system for manufacturing cast products of polyurethane having a constant section according to claim 7, which wherein closing system (11) of the two parts (a, b) of the mold (3) is a closing system by axial and radial pressure that comprises a fixed threaded screw-shaped device (21).

15. The system for manufacturing cast products of polyurethane having a constant section according to claim 9, wherein the closing and joining system (11) is an independent module of the bench (4) further comprising girths or clamps (3) joining the mold parts (a, b) together when the polyurethane foams and pressure is exerted from inside.

16. The system for manufacturing cast products of polyurethane having a constant section according to claim 9, wherein the bench (4) includes moving means, such as a conveyor belt (22) on which the molds (3) are moving, to be passing in line under the product injection system or machine (2).

Description

DESCRIPTION OF THE DRAWINGS

[0055] To complement the description that is being carried out and in order to assist to best understand the characteristics of the invention, attached to this specification, as an integral part thereof, there is a drawing in which, for illustration and no limitation purpose, the following has been represented:

[0056] The FIG. 1.It shows a schematic view of an example of embodiment of the system for manufacturing polyurethane cast products having a constant section object of the invention, the mains parts and elements it comprises can be seen;

[0057] the FIGS. 2-A, 2-B and 2-C.They show respective views in perspective, an example of two extruded parts forming a first example of a two-parts mold for forming a polyurethane profile for a window frame, an example of two other extruded parts forming the two parts of a second example of mold for forming another polyurethane profile, in this case for a window leaf and its respective polyurethane parts obtained with the said molds and forming the frame and leaf profile;

[0058] the FIG. 3.It shows a schematic side elevation view of several molds in the filling step arranged in horizontal, according to the prior art;

[0059] the FIG. 4.It shows a schematic side elevation view of several molds in the vertical filling step, according to the invention, with injection of material by the top end;

[0060] the FIG. 5.It shows a side elevation view of several molds in vertical filling step, according to the invention, with injection of the material by the lower end;

[0061] the FIG. 6.It shows an elevation view of the end of a mold, according to the system of the invention, in an example with closing system by axial pressure with a moving piston-shaped device;

[0062] the figures number 7 and 8.They show both side elevation and top perspective views of an example of bench with molds and closing system by axial pressure with a moving piston-shaped device;

[0063] the FIG. 9.It shows an elevation view of the end of the mold, according to the system of the invention, in an example with closing system by axial pressure with a fixed exchangeable strut-shaped device;

[0064] the FIG. 10.It shows a side elevation view of the bench with the closing system of molds shown in the FIG. 9.

[0065] the FIG. 11.It shows an elevation view of the end of a mold according to the system of the invention, in this case in an example of closing system by axial pressure with a fixed threaded screw-shaped device;

[0066] the FIG. 12.It shows a side elevation view of the bench with the closing system of molds shown in the FIG. 11; and

[0067] the FIG. 13.It newly shows a schematic representation of the main elements of the system for manufacturing polyurethane cast products having a constant section object of the invention, in this case in an example for injection in line with moving bench.

PREFERRED EMBODIMENT OF THE INVENTION

[0068] Seen the figure disclosed, and according to the numerals adopted in them, a non-limiting example of embodiment of the system for manufacturing polyurethane cast products having a constant section of the invention can be seen, which comprises what is disclosed in detail below.

[0069] Thus, as it can be seen in the said figure, the system for manufacturing polyurethane products, preferably products consisting in elongated parts (9), for example profiles for forming frames for doors and windows, essentially comprises the following elements: [0070] a feeder (1) of polyurethane product, [0071] an injection system or machine (2) in line, that injects the product in its liquid or fluid form within the molds (3), [0072] at least, a mold (3) preferably a series of molds (3), having the shape of the parts to be manufactured, that are open by, at least, a top end, and [0073] a bench (4) for placing and fastening the molds (3) located tilted or in vertical.

[0074] Preferably, the system is an automated system that, in a preferred embodiment of the invention, comprises in addition: [0075] a molds (3) provider (5) and extractor (6) system that, first moves the molds (3) towards the injection system (2) and, after the polyurethane has been injected, withdraws them from the injection line (2), for which, preferably, it is formed by two robotic arms, one being provider (5) and the other one being extractor (6), installed on both ends of the bench (4).

[0076] Preferably, the manufacturing system also comprises a storing unit (7) in which the extractor system (6), after the polyurethane foaming within the mold (3), places the molds (3) for their curing, preferably in horizontal position.

[0077] Preferably, the manufacturing system also comprises an opening system (8) of molds that, in the event that they are formed by two parts (a, b) opens the said two parts and, anyway, takes out the cured part (9), taking apart the production line by one side of the mold (3), for its re-use, and by the other the polyurethane parts (9) formed for their finish.

[0078] Preferably, the manufacturing system comprises a molds (3) cleaning system (10), where the molds (3) arrive from the previous opening system (8), for their cleaning and re-use.

[0079] Preferably, the manufacturing system comprises a closing system (11) that, at least, closes exerting axial pressure a mold end (3), preferably the lower.

[0080] In an embodiment, the closing system (11) of the molds (3), that closes them by the lower part, is integrated in the placing and fastening bench (4) itself, by means of an element that keeps the molds (3) closed when the polyurethane foams and the pressure is exerted from inside. Thus, the bench (4), in addition to placing and fastening the injection mold (3), at the same time closes one of the injection mold ends (3), preferably the lower and allows the polyurethane injection by its other end, the top end.

[0081] In addition, when the mold (3) is formed by two parts (a,b), the closing system (11) also comprises closing means with radial pressure to keep the parts of the mold (3) joined to each other.

[0082] According to the FIGS. 6 to 12, three different options of the said closing system (11) are seen without others are discarded.

[0083] Concretely, in a first option, that can be seen in the FIGS. 6, 7 and 8, the closing system (11) that keeps the two parts (a, b) joined that form the mold (3) is a closing system by axial and radial pressure that comprises a piston-shaped moving device (17).

[0084] According to the FIG. 7, it can be seen that the bench (4) where several molds (3) are incorporated, they are closed by their lower end with a lower lid (18) and by its top end, after being filled with a gate-shaped axial pressure element (19), as well as along them with several radial pressure pistons (17).

[0085] In another option of embodiment, shown in the FIGS. 9 and 10, the closing system 11 of the two parts (a, b) of the mold (3) is a closing system by axial and radial pressure that comprises a fixed strut-shaped exchangeable device (20). According to the FIG. 10 it can be seen how in the bench (4), where several molds (3) are incorporated, they are closed by their lower end with a lower lid (18) and by their top end, after being filled, with a gate-shaped axial pressure element (19), as well as along them with several radial pressure struts (20).

[0086] And, in another option of embodiment, shown in the FIGS. 11 and 12, the closing system (11) of the two parts (a, b) of the mold (3) is a closing system by axial and radial pressure that comprises a fixed threaded screw-shaped device (21), According to the FIG. 12, it can be seen how in the bench (4) where several molds (3) are incorporated, they are closed by their lower end with a lower lid (18) and by their top end, after they have been filled, with a gate-shaped axial pressure element (19) as well as along them with several radial pressure threaded screws (21).

[0087] Alternatively, as in the case shown in the example of the FIG. 1, the closing system (11) is a module independent from the bench (4) where the molds (3) are previously closed for example by means of girths or clamps (3) that keep them closed when the polyurethane foams and pressure is exerted from inside.

[0088] Preferably, the molds (3) are manufactured by extrusion, without any type of further modification or adaptation and they are open by their two ends. They can be formed by a single tubular extruded part or by two extruded parts that form the respective parts (a,b) of the molds (3) that are fixed to each other in the closing system (11) that fastens them in vertical position.

[0089] In the FIGS. 2-A, 2-B and 2-C, two examples of embodiment of the said profiles can be seen forming the two parts (a,b) of the mold (3).

[0090] Concretely, in the FIG. 2-A, an example of two extruded parts forming the two parts (a,b) of a first example of mold (3) for forming a polyurethane part (9) profile-shaped for a window frame, in the FIG. 2-B an example of two other extruded parts forming the two parts (a, b) of a second example of mold (3) for forming another profile-shaped polyurethane part (9) for a window leaf and in the FIG. 2-C the respective parts (9) of polyurethane obtained with the said molds (3).

[0091] Optionally, the system comprises a system (12) for covering parts (9) of polyurethane obtained, in which it is proceeded to apply on them a coating or finish covering after taking them apart from the mold (3), likewise, a dispensing system (13) of parts (9) having been provided, that transfers them from the outlet belt (14) of the opening system (8) of the molds (3) to the said covering system (12).

[0092] Although it was not represented, the said covering system (12) can also include cutting means to eliminate a discardable portion of the part, preferably at its top end, in which holes and cavities formed by the CO.sub.2 bubbles had remained accumulated.

[0093] According to the FIG. 4, a schematic representation of the arrangement of the tilted molds (3) can be seen according to the system of the invention, in an example with vertical filling by its top end, through the injection system (2), the top end of the part (9) of polyurethane obtained can be seen, with bubbles only in a portion of its top end, which allows they can be discardable. In this option, the open end of the mold (3) for the inlet of material serves in turn as air outlet (16), which occurs at the same time, therefore, it is only necessary that the mold (3) is open by its top end.

[0094] On its side, in the FIG. 5, an alternative option can be seen in which the material inlet by means of the injection system (2) occurs by the lower part of the molds (3), in which case the existence of an air outlet (16) is contemplated at the top end of the mold (3). This option, although it requires that the mold is open by its two ends, possesses the advantage of avoiding staining and turbulence during the polyurethane liquid resin drop.

[0095] According to the FIG. 3, the difference can be seen of creating bubbles on the full extent of the top face of the polyurethane material when the position of the molds (3) is horizontal, as it occurs according to the prior art, where, with a material inlet (2) the existence of many air exhaust outlets (16) is required to minimize it.

[0096] On the other hand, regardless all the above, in an optional embodiment appearing in the FIG. 13, the bench (4) includes moving means, for example a conveyor belt (22) on which the molds (3) move, preferably fastened through stabilizing guides (23), to be passing in line under the injection system or machine (2) of the product.

[0097] In addition, in this option of embodiment, as closing system (11) that at least closes exerting axial pressure, an axial pressure element (19) is included that closes the top end of the molds (3) and that, preferably, is formed by rollers integrated in a top closing belt (24) allowing to carry out the in-line injection process, either continuous or half continuous of the molds (3).

[0098] Last, it shall be pointed out that, preferably, the polyurethane product used to fully or partly feed the system feeder (1) comprises, full or partly, polyurethane coming from recycled parts (9), previously made in the system itself, after a prior crushing process of them in a micronized crushing device (15) provided in the system prior to the feeder (1).

[0099] Sufficiently disclosed the nature of this invention, as well as the manner of implementing it, it is not deemed necessary to extend anymore its explanation in order that any man skilled in the art understands its scope and the advantages arising from it.