Multiple parking system for injection molds

Abstract

A multiple parking system for injection molds comprising: - a central rod (1); - a flange (2) intended to allow the sliding of said central rod (1) therein; - a groove (4) formed in said central rod (1), wherein said groove (4) is formed by a plurality of interconnected sections (4a, 4b, 4c, 4d); - a guide pin (3) intended to slide in said plurality of sections (4a, 4b, 4c, 4d) of said groove (4) to allow the rotation of said central rod (1); - an insert (6) fixed to and attached to one end of said central rod (1); - at least one mechanical element (7) susceptible of elastic deformation intended to interact with said guide pin (3), wherein each of said plurality of sections (4a, 4b, 4c, 4d) of said groove (4) is formed by portions (5a, 5b, 5c, 5d, 5e) connected to each other and has different depths, characterized in that the multiple parking system for injection molds comprises a tie rod (8) attached to said central rod (1) and has a sliding element that allows said central rod (1) to slide and rotate simultaneously within said flange (2).

Description

Multiple parking system for injection molds Technical field This utility model relates to the field of injection molds. In particular, this utility model relates to a multi-position parking system for injection molds. State of the art. A mold is a piece of equipment that gives a specific shape to a workpiece; it typically consists of two or more semi-frames that define a space with the shape of the final part. The mold is specifically designed according to the manufacturing process used, such as injection molding, die molding, deep drawing, or foaming. Depending on the processing method, the characteristics and technology of the mold change. Molds are closely linked to the type of material they will be used for, whose viscosity, temperature, and characteristics depend on numerous variables. A mold is a piece of equipment that only functions when it is placed inside a machine called a press. Injection molding is an industrial production process in which a plastic material is melted and injected at high pressure into a closed mold, which is opened after the product solidifies. The injection molding cycle begins when the mold closes, followed by the injection of a material, usually a polymer, into the mold cavity. Once the cavity is full, a certain pressure is maintained to compensate for volumetric changes in the material. Once the part has cooled sufficiently, the mold opens and the molded part is ejected. Overmolding (also called comolding) is a specific multi-stage injection molding process in which two or more components are molded one on top of the other. Overmolding with applications is typically used to produce technical articles with parts that usually consist of a rigid, load-bearing part, made of metal or plastic, and an elastic rubber part with sealing functions. The main applications of these articles are related to the automotive, hydraulic, and sanitary sectors. In co-molding, the molding process is somewhat complex; in fact, it is necessary to move the part from the first cavity (where the first material has been molded) to the second cavity (where the second material will be molded). Inserts of non-plastic material can also be introduced. There are different methods of co-molding: a) "transfer system", which uses a mechanical arm that takes the part from the first cavity (station) and places it in the second cavity; b) "rotary table presses", which move the article by rotating the moving part of the mold; this method requires a specific press capable of moving these entire parts of the mold in a short time; c) "index system", normally implemented in rotary table presses which uses a central pin to rotate only some parts of the mold; unlike the "rotary table press" system, not the entire moving part of the mold is rotated, but only the area affected by the change of position. Cycle time, that is, the time spent molding a part, is one of the main variables that affect the cost of a molded product. The Applicant has found that these systems are very expensive and, consequently, in the absence of this equipment, it is very problematic to mold various materials. DE4421410 A1 describes a transmission unit for an injection molding machine comprising an axially movable and rotatable shaft with a cylindrical surface containing grooves extending from both ends. The grooves at one end are circumferentially offset with respect to the grooves at the other end and are connected to each other at the center of the shaft by transition grooves. A guide pin engages and follows the groove. However, the Applicant has found that in the described molding machine there is play between the different mechanical parts which causes unwanted movement between the parts and, consequently, does not allow satisfactory performance. Therefore, the Applicant has raised the technical problem of how to make a device for injection molding of various materials capable of reducing cycle time and, consequently, reducing molding costs, using classic injection presses. Summary The present utility model refers to a multiple parking system for injection molds as indicated in claim 1. The Applicant of this utility model has unexpectedly found that the aforementioned technical problem can be solved effectively and reliably by means of a multiple parking system for injection molds comprising a central rod, a flange that allows said central rod to slide in it, a groove formed in said central rod and consisting of a plurality of interconnected sections. The multiple parking system for injection molds further comprises a guide pin intended to slide in said plurality of sections of said groove to allow rotation of said central rod, an insert fixed to one end of said central rod and attached thereto, and at least one mechanical element susceptible to elastic deformation intended to interact with said guide pin. Each of said plurality of sections of said groove is formed by portions connected to each other and has different depths. Thus, with the multiple parking system of the present utility model, classic presses without a rotary table can be used to have several stations available in the different phases of molding or for other types of processing. In fact, in the multiple parking system of the present utility model, the central rod of the system first slides into the flange; then, due to the difference in depth between the portions of the groove, the pin continues its movement along the deeper groove thanks to the interaction with said mechanical element, thus rotating the central rod and, consequently, the insert affected by the change of position fixed to it. In this way, different phases can be carried out within the same mold and at the same time, without increasing the cycle time, even using classic injection presses. Furthermore, the multiple parking system of the present utility model comprises a tie rod attached to said central rod and has a sliding element that allows said central rod to slide and rotate simultaneously within said flange. Thus, when the press pushes the tie rod, a translational movement is transmitted to the central rod, which also allows its rotation at the same time. According to a preferred embodiment, the sliding element with which the tie rod is provided is a bayonet system intended to couple with the central rod. This facilitates the coupling between the tie rod and the central rod, allowing the rod to move and rotate within the flange. According to a preferred embodiment, the multiple parking system of the present utility model also comprises a plate provided with a coupling device for coupling said central rod and said insert together. This eliminates any potential mechanical play between the two parts. Consequently, even when the central rod and the insert are subjected to repeated and continuous rotations, the two parts remain perfectly joined together, firmly and compactly. According to a preferred embodiment, the coupling device provided with the plate is a male-female coupling. In this way, the game between the parties is also eliminated. According to a preferred embodiment, each of said plurality of sections of said groove is substantially Y-shaped and has a first portion, corresponding to a first arm of the Y, and has: - a first portion having a constant first depth (p1), in which said first portion corresponds to a first section of the first arm of the Y, - a second portion, contiguous to said first portion, in which the depth varies gradually from said first depth (p1) to a second depth (p2), different from said first depth (p1), and in which said second portion corresponds to a second section of the first arm of the Y, and - a third portion, contiguous to said second portion, having a constant depth substantially equal to said first depth (p1) of said first portion, and in which said third portion corresponds to the support of the two arms of the Y. Thus, the slot begins with a first right-hand section of constant depth, then transitions to a second adjacent section with a gradually varying depth to its opposite end. At this end of the second section, there is a first downward drop in depth, after which the pin, through interaction with the elastic element, continues its path into the third section, adjacent to the second section and again of constant depth. According to a preferred embodiment, each of said plurality of sections of said groove also comprises at least: - a fourth portion contiguous to said third portion, in which the depth varies gradually from bottom to top, and - a fifth portion of constant depth, contiguous to said fourth portion, wherein the fourth portion and the fifth portion together form the second arm of the Y-shaped groove. Thus, after the pin has reached the terminal part of the third portion of the constant-depth groove (corresponding, therefore, to the support for the two arms of the Y), the central rod is fully extended. On its return movement, the pin travels back along the entire third portion of constant depth, and reaches the point where, on the outward journey, it made the first downward depth jump (at the end of the second portion of variable depth, its culmination located precisely at the junction between the second and third portions).At this point, the pin, unable to overcome the first depth jump (this time upwards), continues its path, passing first through the fourth portion of variable depth (analogous to the second portion seen previously, but this time from bottom to top) and subsequently through the fifth portion of constant depth, adjacent to the fifth portion, where the fourth and fifth portions together form the second arm of the Y-shaped groove. Corresponding to the point of union between said fourth portion of variable depth and said fifth portion of constant depth, there is a second downward depth jump, analogous to the first depth jump seen previously and located at the point of union between said first portion of constant depth and said second portion of variable depth. According to a preferred embodiment, said fifth portion of constant depth of a first section of said plurality of sections of said groove corresponds to a first portion of a second section of said plurality of sections adjacent to said first section. Thus, once the pin has completed its travel along all the portions that make up the first section of the groove, it is again in position to begin a new travel to cover the second section of the plurality of sections that make up the groove, exactly the same as what was done in the first section. Consequently, the central rod can be rotated as many times as there are portions of grooves. According to a preferred embodiment, said first depth p1 is less than said second depth p2. Thus, the guide pin, when it travels through the second portion of the groove, uses the greater depth of this groove to lift the central rod and rotate it in a certain direction, for example, counterclockwise. According to a preferred embodiment, the depths of the groove portions can be arranged so that the pin travels through these portions in the opposite direction to that previously described, i.e., starting from the second arm of the Y and reaching the first arm of the Y, with a relative rotation of the central rod in the opposite direction, for example, clockwise. According to a preferred embodiment, the depth difference between said first depth p1 and said second depth p2 has a substantially equivalent ratio of 1:1 with respect to the diameter of said guide pin, preferably approximately 6 mm. According to a preferred embodiment, said central rod has a substantially cylindrical shape. According to a preferred embodiment, the flange intended to allow the sliding of the central rod therein also has a substantially hollow semicylindrical shape, wherein the diameter of the central rod is slightly less than the diameter of the flange. In this way, the central rod can slide vertically up and down, along the edge of said flange. According to a preferred embodiment, said mechanical element susceptible to elastic deformation and intended to interact with said guide pin is a spring. In this way, the spring pushes the guide pin towards the bottom of the groove so that the guide pin itself can take advantage of the groove's greater depth during its travel. Therefore, the spring ensures that the guide pin is always in contact with the groove in the center rod. According to a first preferred embodiment, the spring is locked between the guide pin and a plate. According to a first preferred embodiment, said insert has a rectangular shape and said groove is formed by two of said sections. Thus, after the guide pin slides into the two sections of the groove, the central rod first rises and then rotates 90° before descending again. As the rod descends, the guide pin travels along the second arm of the Y-shaped groove, allowing the rod to rotate another 90°. As a result, the insert at the top of the central rod also rotates 180°, thereby changing its position. According to a second embodiment, said insert has a triangular shape and three of said sections are present. Thus, analogously to what was seen previously with reference to the first embodiment, after the guide pin slides into the portions of the three groove sections, the central rod first rises and then rotates 60° before descending again. As the rod descends, the guide pin travels along the second arm of the Y-shaped groove, allowing the rod to rotate another 60°. The result is that the insert, located at the top of the central rod, also rotates 120°. According to a third embodiment, said insert has a square shape and four of said sections are present. Thus, analogously to what was seen previously with reference to the first embodiment, after the guide pin slides into the portions of the four groove sections, the central rod first rises and then rotates 45° before descending again. As the rod descends, the guide pin travels along the second arm of the Y-shaped groove, allowing the rod to rotate another 45°. The result is that the insert, located at the top of the central rod, also rotates 90°. According to a preferred embodiment, the multiple parking system for injection molds of the present utility model further comprises a cooling circuit for cooling the molded parts located on the top of said central rod. According to a preferred embodiment, said central rod is further provided with piercing elements for supplying said inserts with water, air or oil. According to a preferred embodiment, the length of said central rod and its travel varies according to the size of the mold. According to a preferred embodiment, the Y-shape of the slot also varies according to the number of stations. According to a preferred embodiment, the diameter of the central rod varies according to the size of the molded part. Other features and advantages of this utility model will be further highlighted in the following detailed description of preferred, but not exclusive, embodiments, illustrated by way of example only and not as a limitation, with the aid of the accompanying designs. In particular, in those designs: Fig. 1 shows an overview of one embodiment of the system of the present utility model, in which the central rod is in a rest position; Fig. 2 shows the system of Fig. 1, in which the central rod is lifted and rotated; Fig. 3 shows the system of Fig. 1, again in the resting position, but with the insert rotated 180°; Fig. 4 shows a detail of the system in Fig. 1, in which the guide pin and a portion of the slot can be seen; Fig. 5 shows a detail of the system in Fig. 1, in which two consecutive Y-shaped portions of the slot can be seen; Fig. 6 shows a detail of the rod in Fig. 1; Fig. 7 shows a detail of Fig. 6, depicting the plate and coupling device between the central rod and the insert, with the rod not connected to the insert; Fig. 8 shows the detail of Fig. 7, with the rod connected to the insert through the plate; Fig. 9 shows a detail of Fig. 1, in which the tie rod is shown before being connected to the central rod, separated from it; Fig. 10 shows a detail of Fig. 1, in which the tie rod connected to the central rod is represented, viewed axonometrically from below; Fig. 11 shows a side view of the detail in Fig. 10; Fig. 12 shows a detail of a first embodiment of the system of Fig. 1, in which the rectangular-shaped insert and two portions of the groove are schematically represented; Fig. 13 shows a detail of a second embodiment of the present utility model, in which the triangular-shaped insert and three portions of the slot are schematically represented; Fig. 14 shows a detail of a third embodiment of the present utility model, in which the square-shaped insert and four portions of the slot are schematically represented. Detailed description The following detailed description refers to particular ways of implementing the system of this utility model, without limiting its content. With reference to Figs. 1-12, a first embodiment of the system of the present utility model is described. Fig. 1 shows in particular the cylindrical flange 2 within which the central rod 1 slides; the rectangular insert 6 fixed to and attached to the upper end of the central rod 1; and the pull-out tie 8. Fig. 1 also shows, in particular, the cylindrical central rod 1 in its rest position, and the groove 4 formed in the central rod 1 into which the guide pin 3 can slide. Figure 2 shows the same system as Figure 1, in which the central rod is raised and rotated 90° with respect to the position shown in Figure 1. Insert 6, attached to the central rod 1, is also rotated 90°. It should be noted that the positions of elements A and B of insert 6 in Figure 2 are different from those in Figure 1. Figure 3 shows the same system as Figures 1 and 2, in which the central rod is lowered again (thus returning to the rest position shown in Figure 1), but rotated 180° with respect to the position shown in Figure 1. Insert 6, attached to the central ring 1, is also rotated 180°. In this regard, it should be noted that the positions of the elements labeled A and B in Figure 3 are reversed compared to those in Figure 1. Fig. 4 shows a detail of the system of Fig. 1, 2, 3 in which portions 5a, 5b, 5c of a substantially Y-shaped section 4a of the groove 4 in which the guide rail 3 slides are seen. Corresponding to the junction point between portion 5b and portion 5c there is a first depth jump 9a, as described in more detail below. Figure 5 shows another detail of Figure 4 in which two consecutive sections 4a and 4b of slot 4 are seen, each of which is formed by the same portions 5a, 5b, 5c, 5d that together form a kind of Y. In more detail, slot 4a begins with the first portion 5a of straight section with a constant depth p1 (which corresponds to a first section of the first arm of the Y) and then passes to the second portion 5b (adjacent to the first portion 5a, which corresponds to a second section of the first arm of the Y) which has a depth that varies gradually up to the maximum value p2 recorded in correspondence with the end of the second portion 5b, opposite the first portion 5a.Corresponding to the end of the second portion, there is a first downward depth jump 9a, from which the guide pin 3, thanks to its interaction with the spring 7, continues its travel into the third portion 5c, adjacent to the second portion 5b (which corresponds to the support section for the two arms of the Y), and again of constant depth p1. After the guide pin 3 has reached the terminal part of the third portion 5c of the constant-depth groove 4a (corresponding, therefore, to the support for the two arms of the Y), the central rod is fully extended. On its return movement, the guide pin 3 travels back along the entire length of the third portion 5c of constant depth, and reaches the point where, on the outward journey, it made the first downward depth jump 9a.At this point, the guide pin 3, unable to overcome the first depth jump 9a (this time upwards), cannot travel backwards through the second variable-depth portion 5b and continues its path, passing first through the fourth variable-depth portion 5d (analogous to the second portion 5b seen previously, but this time from bottom to top) and subsequently through the fifth constant-depth portion 5e, adjacent to the fifth portion 5d, where the fourth portion 5d and fifth portion 5e together form the second arm of the Y-shaped groove. Corresponding to the point of union between the fourth variable-depth portion 5d and the fifth constant-depth portion 5e, there is a second downward depth jump 9b, analogous to the first depth jump 9a seen previously between the first constant-depth portion 5a and the second variable-depth portion 5b. Thus, the guide pin 3 has traversed the entire cycle of section 4a of the groove, and the central rod 1 has rotated 180°, along with the insert 6 located at its upper end. At the end of this first cycle, the guide pin 3 begins the new cycle, traversing all portions of section 4b of groove 4 in a manner analogous to that seen previously for section 4a, since the fifth portion 5e of section 4a of groove 4 corresponds exactly to the first portion 5a of section 4b of groove 4. Figure 5 also shows the first depth jump 9c and the second depth jump 9d present in section 4b, arranged analogously to the corresponding first depth jump 9a and second depth jump 9b seen previously with reference to section 4a. Spring 7 is used to ensure that guide pin 3 is always in contact with the groove 4 of the center rod 1. Spring 7 is locked between guide pin 3 and a plate. Figure 6 shows in detail the central rod 1, the insert 6, the pin 3, the spring 7, and the piercing elements 10 for supplying the inserts 6 with water, air, and oil. Figure 6 also shows the plate 11 provided with at least one coupling device 12, for example, of the male-female type, for coupling the central rod 1 and the insert 6. See Figures 7 and 8 for details, in which, respectively, the rod 1 is not connected to the insert 6 (Fig. 7) and the rod 1 is connected to the insert 6 via the coupling device 12 (Fig. 8). Thus, the presence of the plate 11 and the coupling device 12 allows the central rod 1 and the insert 6 to be coupled together, eliminating any mechanical play between the two parts. Consequently, even when the central rod 1 and the insert 6 are subjected to repeated and continuous rotations, the two elements 1 and 6 remain perfectly joined together, firmly and compactly. Figures 9-11 show in detail the coupling between the tie rod 8 and the central rod 1 depicted in Figure 1. The tie rod 8 is provided at its upper part with a bayonet system 13. In detail, Fig. 9 shows the tie rod 8 separated from the central rod 1; in Fig. 10, on the contrary, the tie rod 8 connected to the central rod 1 is shown in axonometric view from below, with the bayonet system 13 (not shown in Fig. 10) inserted into the central rod 1. Fig. 11 shows a side view of the detail of Fig. 10. Thanks to the presence of the bayonet system 13 with which the tie rod 8 is provided, when the press pushes the tie rod 8, a translational movement is transmitted to the central rod 1, which also allows its rotation within the flange 2 at the same time. Several embodiments can be obtained, depending on the shape of the insert and the number of sections 5 of the groove 4. Whereas previously, with reference to Figs. 1-12, an embodiment was shown in which the insert 6 has a rectangular shape and there are two sections 4a, 4b of the groove 4 that cause the insert to rotate 180° (see Fig. 12 in detail), other embodiments are shown in Figs. 13 and 14. In particular, Fig. 13 shows a second embodiment of the system of the present utility model, in which the triangular-shaped insert 6 and three sections 4a, 4b, 4c of the slot 4 are schematically represented, which cause the insert to rotate 120°. Similarly, in Fig. 14 a third embodiment of the system of the present utility model is shown, in which the square-shaped insert and four sections 4a, 4b, 4c, 4d of the groove 4 are schematically represented, which cause the insert to rotate 90°. Operationally, in a multiple parking system for injection molds according to the present utility model, the following phases occur: phase 1: closing the mold, joining the moving part with the fixed part; phase 2: injection of the first material into the first cavity, with the mold closed; phase 3: opening of the mold, separating the moving part from the fixed part; Phase 4: displacement of the first solidified material to the second cavity, with the mold open, moving the central bolt of the multiple parking system, as described; phase 5: new mold closure, joining the moving part with the fixed part; Phase 6: Injection of the second material into the second cavity; repetition of phase 2, with the mold closed; phase 7: opening the mold, separating the moving part from the fixed part; Phase 8: Removal of the molded items, with the mold open. Thanks to the fact that with the multiple parking system for injection molds of the present utility model, several different phases can be carried out within the same mold (and at the same time), so as not to increase the cycle time, the multiple parking system for injection molds of the present utility model makes it possible, therefore, to reduce the cycle time and reduce the molding costs, using classic injection presses in all cases. The present utility model can be applied to molds, co-molding or bi-material; however, it can be useful, in general, in all those processes that require some type of rotation of the part, such as in the system of applying labels to plastic containers that involves the application inside the mold before the forming phase, also called IML (In-Mold Labeling), or in a process of extracting the molded article, or also in the injection of the material into a mold. Naturally, for people who are experts in the field, many modifications and variations of the preferred embodiments described above will be evident, still within the scope of the present utility model. Therefore, the present utility model is not limited to the preferred embodiments described, illustrated for indicative and non-limiting purposes only, but is defined in the following claims.

Claims

1. A multiple parking system for injection molds comprising: - a central rod (1); - a flange (2) intended to allow the sliding of said central rod (1) therein; - a groove (4) formed in said central rod (1), wherein said groove (4) is formed by a plurality of interconnected sections (4a, 4b, 4c, 4d); - a guide pin (3) intended to slide in said plurality of sections (4a, 4b, 4c, 4d) of said groove (4) to allow the rotation of said central rod (1); - an insert (6) fixed to and attached to one end of said central rod (1); - at least one mechanical element (7) susceptible to elastic deformation intended to interact with said guide pin (3), wherein each of said plurality of sections (4a, 4b, 4c, 4d) of said groove (4) is formed by portions (5a, 5b, 5c, 5d, 5e) connected to each other and has different depths,characterized in that the multiple parking system for injection molds comprises a tie rod (8) attached to said central rod (1) and has a sliding element that allows said central rod (1) to slide and rotate simultaneously within said flange (2).

2. The multiple parking system for injection molds according to claim 1, characterized in that said sliding element is a bayonet system (13) intended to couple with said central rod (1).

3. The multiple parking system for injection molds according to any of the preceding claims, characterized in that it also comprises a plate (11) provided with at least one coupling device (12) intended to couple said central rod (1) and said insert (6).

4. The multiple parking system for injection molds according to any of the preceding claims,characterized in that each of said plurality of sections (4a, 4b, 4c, 4d) of said groove (4) is substantially Y-shaped, and has: - a first portion (5a) having a constant first depth (p1), in which said first portion (5a) corresponds to a first section of the first arm of the Y, - a second portion (5b), contiguous to said first portion (5a), in which the depth varies gradually from said first depth (p1) to a second depth (p2), different from said first depth (p1), and in which said second portion (5b) corresponds to a second section of the first arm of the Y, and - a third portion (5c), contiguous to said second portion (5b), having a constant depth substantially equal to said first depth (p1) of said first portion (5a),and wherein said third portion (5c) corresponds to the support of the two arms of the Y.

5. The multiple parking system for injection molds according to claim 4, characterized in that each of said plurality of sections (4a, 4b, 4c, 4d) of said Y-shaped groove (4) further comprises: - a fourth portion (5d) contiguous to said third portion (5e), ​​having a variable depth, and - a fifth portion (5e) of constant depth, contiguous to said fourth portion (5d), wherein the fourth portion (5d) and the fifth portion (5e) together form the second arm of the Y-shaped groove (4).

6. The multiple parking system for injection molds according to claim 5, characterized in that said fifth portion (5e) of constant depth of a first section (4a) of said plurality of sections (4a, 4b, 4c,4d) of said groove (4) corresponds to a first portion (5a) of a second section (4b) of said plurality of sections (4a, 4b, 4c, 4d) adjacent to said first section (4a).

7. The multiple parking system for injection molds according to any of the preceding claims, characterized in that said central rod (1) and said flange (2) both have a substantially cylindrical shape, and wherein the diameter of said central rod (1) is slightly smaller than the diameter of said flange (2).

8. The multiple parking system for injection molds according to any of the preceding claims, characterized in that said at least one mechanical element (7) susceptible of elastic deformation intended to interact with said guide pin (3) is a spring.

9. The multiple parking system for injection molds according to any of the preceding claims,characterized in that said insert (6) has a rectangular shape and two of said sections (5) are present, or in that said insert (6) has a triangular shape and three of said sections (5) are present, or in that said insert (6) has a square shape and at least four of said sections (5) are present.

10. The multiple parking system for injection molds according to any of the preceding claims, characterized in that said central rod (1) is further provided with piercing elements (10) for supplying said inserts (6) with water, air, or oil.