MALE ELEMENT OF A MOULD

Abstract

A male element (100) of a mould (10) for the compression moulding of a parison comprises a die (110) and a ducting system (117), located inside the die (110) to allow a cooling fluid to flow in the male element (100), wherein the die (110) comprises: a body (112); a liner (116) fitted round the body (112) and having an outside surface, acting in conjunction with a female element (200) of the mould (10) to delimit a forming cavity (20), and an inside surface in contact with the outside surface of the body (112), wherein the ducting system (117) is formed between the body (112) and the liner (116).

Claims

1.-17. (canceled)

18. A male element of a mould for the compression moulding of a parison from a previously prepared charge of thermoplastic material, wherein the male element is associable with a female element of the mould to delimit a forming cavity intended for forming the parison, and comprises: a die, extending along a longitudinal axis; a ducting system located inside the die to allow a cooling fluid to flow in the male element, wherein the die includes: a body having an outside surface; and a liner fitted round the body and having an outside surface, acting in conjunction with the female element of the mould to delimit the forming cavity, and an inside surface in contact with the outside surface of the body; and wherein the ducting system is formed between the body and the liner.

19. The male element according to claim 18, wherein the outside surface of the body is grooved, so as to create a hollowed surface acting in conjunction with a corresponding portion of the inside surface of the liner to delimit the ducting system.

20. The male element according to claim 19, wherein the ducting system comprises a plurality of grooves.

21. The male element according to claim 20, wherein the outside surface of the body includes a plurality of support zones where it is in contact with the inside surface of the liner, wherein the support zones of the plurality of support zones are alternated with the grooves of the plurality of grooves.

22. The male element according to claim 19, wherein an entire portion of the outside surface of the body, external with respect to the hollowed surface, is in contact with the liner.

23. The male element according to claim 18, wherein the ducting system defines a helix wound around the longitudinal axis.

24. The male element according to claim 18, wherein the ducting system comprises a delivery duct for circulating the cooling fluid towards one end of the die and a return duct for circulating the cooling fluid returning from the end of the die, wherein at least one of the delivery duct and the return duct defines a plurality of passages around the longitudinal axis.

25. The male element according to claim 24, wherein the delivery duct is shaped as a first helix wound around the longitudinal axis and the return duct is shaped as a second helix wound around the longitudinal axis, wherein at least one coil of the first helix is interposed, along the longitudinal axis, between a first and a second coil of the second helix.

26. The male element according to claim 24, comprising a delivery manifold, connected to the delivery duct, and a return manifold, connected to the return duct, wherein the delivery manifold and the return manifold extend in parallel with the longitudinal axis.

27. The male element according to claim 18, comprising a delivery duct, formed inside the body of the die for circulating the cooling fluid towards one end of the die, wherein the ducting system, formed between the body and the liner, defines a return duct for circulating the cooling fluid returning from the end of the die.

28. The male element according to claim 18, further comprising a support structure, wherein the die is retractile relative to the support structure so it can move between a retracted position where, together with the support structure, it contributes to delimiting the forming cavity, and an extracted position where it is configured for stretching the parison.

29. The male element according to claim 18, wherein the die, inside it, has a longitudinal cavity, extending along the longitudinal axis and, at one end of it, a socket in communication with the longitudinal cavity, and wherein the male element also comprises a stretching rod, slidably inserted in the longitudinal cavity and including a terminal portion at one end of it, the stretching rod being movable relative to the die between a retracted position, in which the terminal portion is housed inside the socket to contribute, together with the die, to delimiting the forming cavity, and an extracted position, in which the terminal portion is extracted from the socket so it stretches the parison.

30. The male element according to claim 1, wherein the ducting system comprises a duct delimited by portions of the outside surface of the body and of the inside surface of the liner.

31. A mould for the compression moulding of a parison from a charge of thermoplastic material, wherein the mould comprises: a male element according to claim 18; a female element, associable with the male element to delimit the forming cavity that forms the parison from the charge; and a blow moulding cavity, associable with the male element instead of the female element to delimit a blow moulding cavity intended for the forming of a container from the parison, wherein the mould has a forming configuration in which the male element is associated with the female element and the stretching rod is at the retracted position, to form the parison in the forming cavity, and a stretching and blow moulding configuration in which the male element is associated with the blow moulding cavity and the stretching rod is at the extracted position.

32. The male element according to claim 18, wherein the ducting system is delimited by respective portions of the body and of the liner in mutual contact.

33. The male element according to claim 32, wherein either one or both of the inside surface of the liner and the outside surface of the body is grooved, to form the ducting system.

34. The male element according to claim 18, wherein the body extends along the longitudinal direction to a body tip, the body tip being operatively oriented towards the female element of the mould, and wherein the body has a first portion, with a first diameter, and a second portion, with a second diameter smaller than the first diameter, wherein the second portion is proximal to the body tip and the first portion is distal from the body tip, and wherein the outside surface of the body, in contact with the corresponding inside surface of the liner, is provided both in the first portion and in the second portion of the body.

35. The male element according to claim 18, wherein the ducting system comprises one or more channels which interrupt the contact surface between the inside surface of the liner and the outside surface of the body, this contact surface being provided also in the second portion of the body, and wherein the ducting system is configured for generating a circulation of fluid in the channels, whereby a flow of refrigerating liquid flows through the channels according to a predetermined flow path.

36. A method for the compression moulding of a parison, the method comprising the following steps: receiving a previously prepared charge of thermoplastic material in a mould; forming the parison from the charge in a forming cavity delimited by a male element and a female element of the mould, wherein the male element comprises a die, extending along a longitudinal axis, and a ducting system, located inside the die to allow a cooling fluid to flow in the male element, wherein the die comprises: a body having an outside surface; and a liner fitted round the body and having an outside surface, acting in conjunction with the female element of the mould to delimit the forming cavity, and an inside surface in contact with the outside surface of the body, wherein the ducting system is formed between the body and the liner; wherein the method comprises a step of cooling the die by passing a cooling fluid through the ducting system.

37. The method according to claim 36, wherein the cooling fluid flows in delivery duct towards one end of the die and in a return duct returning from the longitudinal end of the die, wherein at least one between the delivery duct and the return duct defines a plurality of passages around the longitudinal axis.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0041] These and other features will become more apparent from the following description of a preferred embodiment, illustrated by way of non-limiting example in the accompanying drawings, in which:

[0042] FIG. 1A illustrates a mould according to one or more aspects of this disclosure, in a forming configuration;

[0043] FIG. 1B illustrates the male element of the mould of FIG. 1A with a stretching rod at the extracted position;

[0044] FIG. 2 illustrates the body of the male element of the mould of FIG. 1A;

[0045] FIG. 3A illustrates a further embodiment of the mould according to this disclosure, in the forming configuration;

[0046] FIG. 3B illustrates the male element of the mould of FIG. 3A with a die at the extracted position;

[0047] FIG. 4A illustrates the body of the male element of the mould of FIG. 3A;

[0048] FIG. 4B illustrates the body of FIG. 4A in a longitudinal cross section;

[0049] FIG. 5A illustrates a further embodiment of the body of the male element of the mould of FIG. 3A;

[0050] FIG. 5B illustrates the body of FIG. 5A in a longitudinal cross section.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0051] With reference to the accompanying drawings, the numeral 10 denotes a mould.

[0052] The mould 10 comprises a male element 100 and a female element 200, movable between an open configuration, in which they are spaced apart, for receiving a charge, and a closed configuration, in which they are close together to delimit a forming cavity 20 for forming a parison from the charge.

[0053] The mould 10 also comprises a blow moulding cavity, not illustrated, associable with the male element 100 instead of the female element 200 to form a container from the parison.

[0054] The male element 100 comprises a die 110. The die 110 extends along a longitudinal axis to an end 110A. The die 110 juts from a remaining part of the male element 100 along the longitudinal axis A; thus, the die 110 forms a protrusion of the male element 100, configured to be inserted into the female element 200. The die 110 comprises a body 112. The die 110 also comprises a cooling circuit 114, configured to make the cooling fluid flow in the die 110. The die 110 comprises a liner 116 fitted round the body 112. A ducting system 117 forming part of the cooling circuit 114 is formed between the liner 116 and the body 112. More specifically, the body 112 is inwardly curved in such a way as to have one or more hollowed surfaces, which, together with a corresponding portion of the liner 116, delimit the ducting system 117. The body 112 also has non-grooved zones defining support surfaces 112A on which the liner 116 is supported. In other words, the liner 116 is in contact with the body 112 at the support surfaces 112A.

[0055] The cooling circuit 114 comprises a delivery duct 117A, 119 to guide the fluid to the proximity of the end 110A of the die 110, and a return duct 117B to guide the fluid returning from the end 110A of the die 110.

[0056] Preferably, at least one between the delivery duct 117A, 119 and the return duct 1178 has the shape of a helix wound around the longitudinal axis A.

[0057] In an embodiment, the delivery duct 117A has the shape of a first helix wound around the longitudinal axis A and the return duct 117B has the shape of a second helix wound around the longitudinal axis A. The first helix and the second helix are wound round each other, so at least one coil of the first helix is interposed between two consecutive coils of the second helix and at least one coil of the second helix is interposed between two consecutive coils of the first helix. The helically shaped delivery duct 117A and return duct 1176 are located in a zone of the die 110 whose cross section is converging towards the end 110A. In an embodiment, the cooling circuit 114 also comprises a delivery manifold 117A, connected to the delivery duct 117A for bringing together the flow of cooling fluid, and a return manifold 1176, connected to the return duct 1176 to extract the cooling fluid therefrom. The delivery manifold 117A and the return manifold 1176 run parallel to the longitudinal axis A. Thus, the cooling fluid flows down the delivery manifold 117A and along the delivery duct 117A to the proximity of the end 110A of the die 110, then along the return duct 1176 and up the return manifold 1176.

[0058] In this embodiment, therefore, the ducting system 117 between the body 112 and the liner 116 defines the delivery duct 117A and the return duct 1176 for the cooling fluid. Preferably, a support surface 112A is defined between each coil of the delivery duct 117A and the adjacent coil of the return duct 1176.

[0059] In an embodiment, the central delivery duct 119 is formed in a cavity inside the die, extending along the longitudinal axis A, and the return duct 1176 is defined by the ducting system 117 between the body 112 and the liner 116. Thus, in this embodiment, the cooling fluid flows down inside the body 112 through the central delivery duct 119 and flows back up through the return duct 1176 between the body 112 and the liner 116.

[0060] In an embodiment, the return duct 1176 formed between the body 112 and the liner 116 may be spiralthat is, helicalin shape. Thus, the ducting system 117 defines a plurality of coils around the longitudinal axis A. In this case, therefore, the ducting system 117 includes a plurality of passages which are connected to each other in series. A non-hollowed support surface 112A, where the body 112 is in contact with the liner 116, is defined between each coil and the next.

[0061] In an embodiment, the return duct 1178 formed between the body 112 and the liner 116 may be defined by a plurality of grooves extending along the longitudinal axis A. These grooves are connected to each other in parallel. In this case, therefore, the ducting system 117 includes a plurality of passages which are connected to each other in parallel.

[0062] Other variants of shape for the delivery and return ducts, not illustrated, are also imaginable. In an example embodiment, both the delivery duct and the return duct may include a plurality of grooves extending along the longitudinal axis and connected to each other in parallel. In another example embodiment, the delivery duct is defined by a helical ducting system between body and liner, whilst the return duct is formed in a cavity inside the body of the die. In another example embodiment, one between the delivery duct and the return duct is formed in an internal cavity inside the body of the die and the other between the delivery duct and the return duct is defined by a coil formed between body and liner; the coil might be made up of a plurality of grooves extending along the longitudinal axis and connected to each other in series.

[0063] In an embodiment, the die 110 has a socket 111, or recess, at its longitudinal end 110A. In this embodiment, the die 110, inside it, has a longitudinal cavity 113, extending along the longitudinal axis A. The longitudinal cavity 113 is formed in the body 112 of the die 110. The longitudinal cavity 113 communicates withthat is, opens ontothe socket 111. In this embodiment, the male element 100 also comprises a stretching rod 120 which is slidably inserted in the longitudinal cavity 113. The stretching rod 120 has an elongate body extending along the longitudinal axis A and a terminal portion 121 connected to one end of the elongate body. The terminal portion 121 is wider than the elongate body. Preferably, the longitudinal cross section of the terminal portion 121 becomes progressively wider away from the elongate body. The stretching rod 120 is movable between a retracted configuration, in which the elongate body is inserted in the longitudinal cavity 113 and the terminal portion 121 is inserted in the socket 111, and an extracted position, in which the elongate body is partly extracted from the longitudinal cavity 113 and the terminal portion 121 is extracted from the socket 111. It should be noted that the terminal portion 121 is larger in cross section than the longitudinal cavity 113 so it cannot enter the longitudinal cavity 113. Preferably, the terminal portion 121 has a flared shape. This embodiment is illustrated by way of an example in FIGS. 1A and 1B.

[0064] In this embodiment, the die 110 acts in conjunction with the female element 200 and with the terminal portion 121 of the stretching rod to form a bottom and a side wall of the parison, while the support structure 150 acts in conjunction with the female element 200 to form the neck of the parison.

[0065] It should be noted that in this embodiment, the stretching rod 120 is spaced from the wall of the body 112 defining the longitudinal cavity 113. Thus, there is a gap 115 between the stretching rod and the wall of the body 112 defining the longitudinal cavity 113. The gap 115 has a tubular shape around the stretching rod 120. In the embodiment illustrated, the gap 115 is wider in a zone far from the end 110A of the die 110 and narrower in a zone close to the end 110A of the die 110. The gap 115 is configured to channel the air flow used for blow moulding the parison. In effect, once it has been formed, the parison is blow moulded to make a container. The gap 115 runs along the longitudinal axis A as far as the socket 111, where it has an outlet 115A through which the blow moulding air is emitted. When the stretching rod 120 is at the retracted position, the terminal portion 121 occludes the outlet 115A; when the stretching rod 120 is at the extracted position, the outlet 115A is open to allow the blow moulding air to flow out of the gap 115.

[0066] In this embodiment, preferably, both the delivery duct 117A and the return duct 117B of the cooling circuit 114 are defined by the ducting system 117 between the body 112 and the liner 116. In effect, it would not be easy to form the ducts inside the body 112 of the die 110 since it contains the cavity 113 for the stretching rod 120.

[0067] In an embodiment, the die 110 is movable relative to a support structure (or upper part) 150 of the male element 100. In this embodiment, the support structure 150 has a cavity that extends along the longitudinal axis A; the male element 100 also comprises a rod 151 which is slidably inserted in the longitudinal cavity of the support structure 150. The rod 151 has one end fixed to the die 110. Thus, the die 110 is movable relative to the support structure 150 between a retracted position, where it is in contact with the support structure 150 in order to form the parison, and an extracted position, where it is spaced from the support structure 150 in order to stretch the parison. In this embodiment, the forming cavity 20 is delimited by the female element 200, the die 110 and the support structure 150. More specifically, in this embodiment, the die 110 acts in conjunction with the female element 200 to form a bottom and a side wall of the parison, while the support structure 150 acts in conjunction with the female element 200 to form the neck of the parison.

[0068] This embodiment might comprise a blow moulding air duct, not illustrated, inside the rod 151 and the body 112 of the die 110. Alternatively, the blow moulding air may be channeled by a gap between the rod 151 and the support structure 150.

[0069] In this embodiment, preferably, the cooling circuit 114 includes the central delivery duct 119 inside the die 110 and the return duct 1178 between the body 112 and the liner 116. Alternatively, the delivery duct might be defined between the body and the liner might be inside the die.