MXPA00008182A

MXPA00008182A - Mold block with air flow control

Info

Publication number: MXPA00008182A
Application number: MXPA/A/2000/008182A
Authority: MX
Inventors: Manfred A A Lupke; Stefan A Lupke
Original assignee: Manfred A A Lupke; Stefan A Lupke
Priority date: 1998-03-26
Filing date: 2000-08-21
Publication date: 2001-11-21

Abstract

A mold block which is used in a moving mold tunnel comprises first and second mold block sections (3, 5) which meet at their parting faces (4, 6) to close the mold block. Each mold block section has a product shaping interior surface (15, 35) and an air movement passage (11, 30). An air flow controller is provided in each mold block section (3, 5). Through various different positionings of the two air flow controllers, the mold block can be operated in any one of four different modes including a first vacuum forming mode in which air is withdrawn from the mold block through both of the mold block sections (3, 5), a second vacuum forming mode in which air is withdrawn from the mold block through only one of the mold block sections, a third cooling mode in which air is introduced into the mold block through one of the mold block sections and is then withdrawn from the other of the mold block sections and a fourth blow molding mode in which pressure within the mold block is released through both mold block sections (3, 5).

Description

BLOCK MOLD WITH AIR FLOW CONTROL FIELD OF THE INVENTION The present invention relates to a mold block which is used in a mobile mold tunnel and which is particularly useful in the molding of plastic tube with profile. BACKGROUND OF THE INVENTION Corma Inc, of Toronto, Ontario, Canada, has for many years been manufacturing and selling equipment for plastic tube molding as described in U.S. Patent No. 5,002,478, issued March 26, 1991 in favor of Lupke. This equipment includes mold block sections that run on endless tracks and join together to form complete mold blocks which are transported along a moving mold tunnel. The Corma mold blocks include the feature of slot openings in the interior surfaces of the mold blocks, which provide openings for passing air out of the mold blocks. These empty slots that carry the blocks molds have demonstrated their great efficiency in the formation of vacuum in plastic tubes where the vacuum has been induced in both sections of the block mold. They have also been used, to a lesser extent, in tube blow molding.

To date, the mold block of Corma has not been used for cooling purposes where it is very important to provide the cooling of both the tube and the block mold used in the manufacture of the tube. Said cooling substantially increases the production speed of the tube mold. U.S. Patent 4,718,844 to Dickhut shows a mold block with cooling channels running between the face of the mold and the outer surface of the mold block. These channels do not provide cooling air directly to the molding area nor do they have controls for the movement of air through the channels and between the sections of the mold block. COMPENDIUM OF THE INVENTION It has now been discovered that by providing airflow controls in specified locations a block mold of the Corma type described above can be used not only as it has been in the past, but also for additional purposes. More particularly, a mold block which is used with similar mold blocks in a moving mold tunnel comprises first and second sections of the mold block, each of which has a passage for air movement which includes an inlet, a first opening to the inner surface of the product formation and a second opening to the partition face of each section of the block * mold. When the two sections of the mold block are closed with one another in their partition faces, the opening of the partition face in the first section of the mold block joins the opening of the partition face in the second section of the mold block. First and second air flow controllers are also provided, which move independently of one another between an air flow and an air lock position. The first air flow controller is located between the opening of the partition face and the opening of the interior surface in the passage in the first section of the mold block and the second air flow controller is located between the entrance and the opening of the interior surface in the passage of the second section of the mold block. The mold block described above can be used in any of four different modes of operation including a first vacuum forming mode in which air is withdrawn from the mold block through both mold block sections, a second forming operation mode of vacuum in which the air is withdrawn from the mold block through only one of the mold block sections, a third cooling operation mode in which the air is introduced to the mold block through one of the sections of the block mold and that is removed from the block mold through the other section of the mold block, and a fourth mode of blow molding in which the air pressure is released from the mold block through both sections of the mold block. In accordance with the present invention, a mold block having airflow controllers as described above, has substantially improved the versatility over known Corma mold blocks. BRIEF DESCRIPTION OF THE DRAWINGS The above advantages as well as other advantages and features of the present invention will be described in greater detail according to the preferred embodiments of the present invention in which: Figure 1 is a schematic view of the apparatus for molding of tubes; Figure 2 is an enlarged perspective view of the separate sections of the mold block that are joined with their partition faces to form a mold block according to the preferred embodiment of the present invention; Figures 3 to 6 are sectional views through the mold block formed by the sections of the mold block of the Figure 2 showing the different and different modes of operation of the mold block; Figure 7 is a perspective view of the air flow control region of one of the sections of the mold block of Figure 2 and that also shows a specific type of air flow controller usable in the flow control region of air according to the preferred embodiment of the present invention; Figure 7a is a view similar to Figure 7 showing an alternative form of the air flow controller according to a preferred later embodiment of the present invention; Figures 8 and 9 are sectional views through a simplified mold block showing different operating positions of the air flow controller of Figure 7. DETAILED DESCRIPTION ACCORDING TO THE PREFERRED MODALITIES OF THE PRESENT INVENTION Figure 1 shows a Tube molding apparatus generally indicated at 1. This apparatus comprises an extruder (3) feeding molded plastic in a downstream direction towards a tube mold to form a tube with profile generally indicated in P. The tube mold is formed by the upper and lower part of the mold block sections (3) and (5) each of which is transported around the worm track as shown in Figure 1. Where the mold block sections are joined to one another, they form a mobile molding tunnel, generally indicated in FIG. T. Figure 2 shows in greater detail the two sections of the mold block (3) and (5) which are joined to each other on their partition faces (4) and (6) respectively to form a complete mold block. The mold block section (3) has a mounting base (7) which is the region of the mold block that is secured to the infinite track or to the mold block carrier (not shown) on the infinite track. An air manifold (9) is provided in the mounting base of the mold block section (3). The manifold (9) will preferably be in constant communication through the mold tunnel with an external source of air pressure that controls or determines the air pressure within the mold block. A similar manifold (29) is provided in the base (27) of the mold block section (5). Returning to the section of the mold block (3), this includes an interior shaped surface of the product generally indicated at 15. This surface is formed by alternating ridges and chasms (17) and (19) respectively. A small groove is continuously provided around each of the semicircular chasms (21) on the surface (15) of the mold block (3). More than one slot can be provided in each chasm. The section of the mold block (5) has an interior surface (35) identical in shape to the surface (15) and is also provided with grooves (38) as seen in Figure 7. The grooves in the surface (35) coincide with the grooves in the surface (15) to form a series of continuous slots from side to side around the circular chasms formed when the two sections of the mold block meet one another. The sections of the block mold shown in the Figure 2 are used to form tubes with annular ribs where the ribs of the tube are separated from one another. As will be appreciated, these sections of the mold block can be replaced by modified sections of the mold block used to form helical rib tubes in which case, instead of having individually spaced grooves, there will be a continuous helical groove around the inner surface of the mold block. block mold. The mold block section (3) also includes a plurality of air passages (11) through the section of the mold block. Similar air passages (30) are provided in the mold block section (5). The entrances (8) to the air passages (11) open directly towards the manifold (9). The air passages then extend through the section of the mold block (3) diverging towards opposite sides of the forming surface of the interior of the product (15). The passages extend tangentially to the semicircular shaped face of the product and terminate in the openings of the opening face (12).

The air passages (30) in the mold block section (5) have inlets (31) in the manifold (29) and terminal openings (32) in the partition face (6) of the mold block section (5) . When the two sections of the mold block are closed together, the openings of the partition face (32) of the passages (30) meet the openings of the partition face (12) of the passages (11). These then form a plurality of air channels completely through the mold block. As will be seen in Figure 2, there is a plurality of passages on each side of the interior shaped surface of the product of each section of the mold block. These passages are separated from each other throughout the length of each section of the mold block. The section of the mold block (3) includes a back set of shorter passages (13) extending from the manifold (9) radially in the section of the mold block (3). A similar set of short passages (33) extending from the manifold (29) in the mold block section (5) is provided.

The mold block section (3) includes a pair of holes (23) and a rear hole (25) through the mold block section. Similar holes (37) and (39) are provided through the mold block section (5). Each of these holes opens to the grooves formed in the inner surfaces of the two sections of the mold block. In the section of the mold block (3), the passages (11) open towards the holes (23) and the passages (13) open towards the hole (25). In the section of the mold block (5), the passages (30) open towards the holes (37) while the passages (33) open towards the hole (39). As will be understood from the above on the section of the block mold (3), each of the passages (11) has openings in the manifold (9), in the hole (23) and in the partition face of the section of the block mold (3). The passages (13) have openings (14) in the manifold (9) and openings (16) in the orifice (25). The holes (23) and (25) provide air paths of the passages (11) and (13) respectively towards the grooves in the inner surface of the mold block section (3). In the section of the mold block (5) there is a similar configuration, in which the passages (30) have openings in the manifold (29), in the holes (37) and in the partition face of the section of the mold block ( 5) . Also the passage (33) has an opening (36) in the hole (39) and an opening (34) in the manifold (29). The holes (37) and (39) provide direct air routes for the passages (30) and (33) towards the grooves in the inner surface (35) of the mold block section (5). The key to the present invention lies in the provision of air flow controls that dictate the movement of air in the mold block formed by sections 3 and 5 of the mold block. Figures 3 to 6 of the drawings show the provision of those air flow controllers and the positions they can assume to provide various and different modes of operation of the mold block. Figure 7 of the drawings shows that the lower section of the mold block (5) is provided with a hole (48) that penetrates through the air passage separated by a space (30). The hole (48) is between the hole (37) and the openings of the partition face (32) of the passages (30). Although Figure 7 only shows one side of the mold block section (5), the other side of the mold block section has an identical configuration. A rotary valve (49) fits inside the hole (48) and extends through all the air passages (30). The valve (49) has a maximum diameter equal to the inside diameter of the hole (48). The valve is provided by a series of flat portions (55) along its extension and each of these flat parts is located in one of the air passages (30). As you will see in Figure 8, the valve can be placed with its flat parts parallel to the longitudinal axis of the passageway (30) to allow air to flow past the valve or to be rotated 90 degrees from the position of Figure 8 to the position of the valve. Figure 9, where the valve blocks the flow of air through the passage. For the passages (11) and passages (13), similar valves (45) are provided for the mold block section (3). However, these valves are located between the upper ends of the passages (11) that open towards the manifold (9) and the orifices (23) through which the passages (11) pass. The operation of the valves (45) is identical to the operation of the valves (49). However, it should be noted that valves (45) and (49) will operate independently of one another. Figure 7a shows an alternate type of valve (57) which is nothing more than a pin that is removed from the orifice (48) of the mold block section (5) to allow air to move in both directions through the passages (30). However, when the plug is inserted into the hole (48), this blocks the movement of air through the passages. Any of the above types of valves is easily usable with the sections of the mold block, the valve (49) having the benefit that it does not need to be removed, but simply rotated using the receiving head tool (51) of the valve. The mold block, as described above, is useful in different modes of operation. Some of these modes of operation are shown in Figures 3 to 6.

Referring specifically to Figure 3, it will be seen that keeping the valves (45) and (4) open and holding the manifolds (9) and (29) of the mold block sections (3) and (5) respectively to achieve the vacuum , the air flows along the slots in the inner faces of the two sections of the mold block out of the upper section of the mold block through the holes (23) and (25) and also outwards from the lower section of the mold block (5) through the holes (37) and (39). Therefore, in this mode of operation, the vacuum applies to both sections of the mold block. Figure 4 of the drawings shows a situation in which the valves (45) close and the valves (49) remain open. The manifold (29) of the lower section of the mold block (5) is subjected to vacuum and the air leaves the mold block as indicated by the arrows in Figure 4 only of the lower section of the mold block. However, it should be noted that due to the coupling of the openings in the partition face of the air passages in the lower and upper sections of the mold block, part of the air initially comes out of the mold cavity not only through the openings in the mold. the lower section of the mold block, but also the holes (23) of the upper section of the mold block. Therefore, although the vacuum is only applied in the lower section of the mold block, the upper section of the mold block will still be subject to vacuum, ensuring a uniform distribution of the plastic parison (61) which is used to form the tube completely around the inside surface of the cavity inside the mold block. The mold block of Figure 4 has the benefit that it does not need to be used with a molding apparatus having vacuum characteristics at both ends of the mold tunnel, but rather requires that the vacuum systems be applied only to one end of the mold tunnel substantially reducing the costs of the general molding apparatus. In the arrangement of Figure 5, it will be seen that instead of using the vacuum formed, blow molding can be used as indicated by the arrows within the parison (61) to force the parison toward the interior surfaces of the sections of the parison. block mold. In this case, like the configuration of Figure 3, all the valves are left in the air flow position which allows the air trapped between the parison and the inner surface of the mold block to be released through all the passages of air. Figure 6 shows an operation mode of the mold block that is unique and beneficial. This mode of operation is used to cool both the tube within the tunnel of the movable mold, as well as the sections of the mold block as they move along the mold tunnel.

More specifically, in my joint pending patent application, I describe how, after the tube is initially formed inside the mold tunnel using any of the formation methods of Figures 3 through 5, there will be a tendency for the tube to contract from the inside the surfaces of the mold block sections. This occurs when the tube is still in the mold tunnel. As a result, a gap (G) between the formed tube and the inner surface of the mold block is produced. The configuration of Figure 6 takes advantage of this contraction of the tube to provide better cooling of both the tube and the mold block sections. More specifically, the valves (49) in the lower section of the mold block (5) are placed in the air lock position while all the valves in the upper section of the block are placed in the air flow position. The air, which may be of the environment or cooled, is taken from outside the lower section of the mold block (5) is introduced from the base of the lower section of the mold block and along the channels (30) and (33) ) towards the space (G) through the holes (37) and (39) respectively. This air then flows around the tube in the space (G) and is withdrawn in the holes (23) and (25) of the mold block section (3), the manifold (9) remaining subject to vacuum. The valves (49) which are in the blocking position prevent the cooling air from being directed directly through the mold block without passing around the tube. The cooling air not only has a cooling effect on the tube, but additionally has a cooling effect on each of the sections of the mold block by initially passing through the mold block section (5) and then being withdrawn through the mold block section (3). Although several preferred embodiments of the present invention have been described in detail, those skilled in the art will appreciate that variations can be made without departing from the spirit of the invention or the scope of the appended claims.

Claims

1. A mold block for use in a moving mold tunnel (T), the mold block comprises first and second sections of the mold block, (3,5) each of which has an interior surface for forming the product (15,35). ) and a partition face (4,6). Characterized in that each mold block section further includes a first passage for air movement (11,30) in which each passage has an entrance (8,31), a first opening (23,37) in each passage towards the inner surface of the product (15,35) and a second opening (12, 32) towards the partition face (4, 6), the second opening (12) of the passage (11) in the first section of the mold block ( 3) is in communication with the second opening (35) of the passage (30) in the second section of the mold block (5) when the sections of the mold block are closed in their partition faces one with another, and the first and second air controllers (45, 49) move independently from each other between the air flow and air lock position, the first air flow controller (45) is located between the first opening (23) and the second opening (12) in the passage (11) in the first section of the mold block (3), and the second air flow controller (49) is located between the inlet (31) and the first opening (37) in the second section of the mold block.

2. A mold block as claimed in claim 1 is characterized in that said mold block is usable in numerous and different modes of operation comprising a first vacuum forming mold in which both air flow controllers (45,49) are placed in a position of air flow in which air is removed from the mold block through both sections of the mold block (3, 5), a second vacuum forming mode in which the first air flow controller (45) ) is placed in the air flow position, the second air flow controller (99) is placed in the air block position and air is removed from the mold block only through the first section of the mold block (3). ), a third cooling operation mode in which the first air flow controller (45) is placed in the air lock position, the second air flow controller (49) is placed in the flow position of air , the air for cooling the mold block is introduced to the mold block through the second section of the mold block (5) and is removed from the mold block through the first section of the mold block (3) and a fourth mode of operation of the mold block (3). blow molding in which both air controllers (45, 49) are placed in the air flow position and the air pressure is released from the mold block through both sections of the mold block (3, 5).

3. A mold block, as claimed in claim 1, wherein each section of the mold block (3, 5) has a plurality of spaced slots (21, 36) on the inside face (15, 35) thereof. grooves (21) in the first section of the mold block (3) are aligned with the grooves (38) of the second section of the mold block (5), characterized in that the first opening (23, 37) communicates with the groove (21). , 34) in each section of the mold block (3, 5).

4. A section of the mold block, as claimed in claim 1, wherein each section of the mold block (3.5) has a mounting base (7, 27) characterized in that the entrance (8, 31) to the passage of Air movement (11, 30) is located in the mounting base (7, 27) of each section of the mold block (3, 5).

5. A mold block, as claimed in claim 4 usable with other similar mold blocks to form a moving mold tunnel (T), each section of the mold block (3, 5) has an air movement groove (21, 38) extending through the interior surface (15, 35) thereof, the mold block is characterized in that the air passage (11, 30) comprises two diverging air paths (11, 30) through each section of the mold block, each air path having an opening of the manifold (8, 31) in the air manifold (9, 29) provided in the base (7, 27) of each section of the mold block (3, 5), an opening in the partition face (12, 32) and an opening slot (23, 37) between the opening of the manifold and the opening of the partition face.

6. A mold block, as claimed in claim 5, wherein the inner surface of the product form (15, 35) of each section of the mold block (3, 5) has a semicircular configuration and is characterized in that each air path (11, 30) extends tangentially of the inner surface in each section of the mold block.

7. A mold block, as claimed in claim 6, characterized in that each section of the mold block (3, 5) includes another air passage (13, 33) between the air paths (11, 30), this other passage of air (13, 33) that opens at one end (14, 34) towards the air manifold (9, 29) and opens at the other end (16, 36) toward the air movement slot (21, 38). ) on the forming surface of the product (15, 35) of each section of the mold block, and another air flow controller (47) which is also movable between the positions of air lock and air flow in the passage of air (13) of the first section of the block mold (3).