Neck ring for blow mold equipped with anti-rotation means for preforms during blow mold closure
The neck ring with smooth transitions between edges addresses the issue of preform rotation in blow molding, enhancing mold alignment and reducing defects in container production.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- SIDEL PARTICIPATIONS SAS
- Filing Date
- 2024-12-20
- Publication Date
- 2026-06-26
AI Technical Summary
Existing neck rings in blow molding processes potentially cause preforms to rotate around their vertical axis, leading to defects in the blown containers due to sharp edges catching on the preform, compromising concentricity and height consistency.
A neck ring design featuring two semi-annular parts with smooth transitions between edges, such as chamfers or fillets, to prevent preform rotation by eliminating sharp edges.
Prevents preform rotation during mold closure, ensuring consistent concentricity and height, thereby reducing defects in the molded containers.
Smart Images
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Abstract
Description
Title of the invention: Neck ring for blow mold equipped with means to prevent preform rotation during blow mold closure. Technical field
[0001] The present invention relates to the field of molding containers such as bottles from preforms in polyethylene terephthalate (PET) and / or recycled polyethylene terephthalate (rPET), or in any other equivalent material such as polypropylene (PP) for example, which are blown into a mold and, more particularly, a neck ring for a blow mold, said neck ring being provided with anti-rotation means for the preforms when closing the blow mold. State of the art
[0002] In the field of plastic bottle production, it is well known that a plastic blank, also called a parison or preform, can be heated, placed in a blow mold, and then blow-molded to its final size. This is generally done using blow molds, which are closed around the outside of the blank to be blown, and then compressed air is injected through the opening of the mold.
[0003] The mouth of the future bottle, commonly called the neck, is already formed on the parison and is not treated subsequently. For the actual blowing operation, a circumferential edge or collar of the parison rests on a circumferential edge of the blow mold, commonly called the neck ring, thus preventing the preform from collapsing inside the blow mold, the neck of the preform, and more specifically the collar of said neck, bearing on said neck ring.
[0004] In other words, as soon as the blow mold is closed, the preform rests directly on a plane of the blow mold and / or a neck ring, said neck ring being usually removable in order to adapt the dimensions of said neck ring according to the dimensions of the preforms used.
[0005] Such neck rings are well known and are described in documents WO0185435, US6113377 and EP1964660 among others.
[0006] Document WO0185435 describes an apparatus and method for blow molding large-capacity containers. More particularly, this document describes a blow mold for use in a rotary blow molding machine, comprising at least two blow-molded segments together defining an internal cavity The mold is container-shaped and incorporates a cooling circuit in each segment. It consists of two mold segments, divided along a radial plane. Together, these mold segments define an internal container-shaped cavity. The mold can open and / or close in a hinged manner around the radial plane. The mold segments align at their upper edge to form a neck ring, which defines an opening capable of receiving a preform inside, forming a seat with the neck ring.
[0007] US patent 6113377A describes a mold forming a cavity for extruding / blowing articles using an extrusion / blowing apparatus and comprising a support attached to said extrusion / blowing apparatus, the wall of which defines a recess in the support, and a removable insert called a neck ring that fits into said recess and whose surface forms part of the molding cavity. The support and the neck ring are aligned by means of cooperating locating means respectively located on the insert and the support element.
[0008] Document EP1964660 describes a neck ring for a blow mold with a flat peripheral edge against which the neck of a container to be treated can rest, and with a cylindrical segment extending perpendicularly to the plane of the peripheral edge. A spacer means projecting radially from the cylindrical segment inward is provided against the cylindrical segment. The spacer means can reduce a forming gap between the container to be treated and a neck area of the blow mold, and a radially narrowed area of the neck area of the container to be treated can be obtained by the spacer means. Furthermore, a gap between a wall of the spacer means and a wall of the cylindrical segment is between 0.2 and 1.2 mm.
[0009] All these prior art neck rings have the disadvantage of potentially catching on the preform and, ultimately, causing the preform to rotate around its vertical axis, i.e., around its axis of revolution, when the mold is closed, such that concentricity and heights between the preform and the mold are not guaranteed, leading to defects in the blown container in said mold. Disclosure of the invention
[0010] One of the aims of the invention is therefore to remedy all or part of these drawbacks by proposing a neck ring of simple and inexpensive design which makes it possible to eliminate, and at the very least limit, the rotation of the preform when closing the mold and / or inserting the preform into it.
[0011] To this end, and in accordance with the invention, a so-called neck ring for a blow mold is proposed, consisting of two semi-annular parts, each semi-annular part of said ring comprising an internal peripheral edge semicircular forming a cylindrical segment extending perpendicularly to the plane of the peripheral edge, an external semicircular peripheral edge and two diametrically opposed lateral edges, said lateral edges connecting the ends of the external and internal peripheral edges, each hemi-annular part of said ring also comprising a planar hemi-annular shoulder extending along the internal peripheral edge, from one lateral edge to the other; said neck ring is notable in that at least the edge between the planar hemi-annular shoulder and the lateral edges of at least one of the hemi-annular parts and the edge between the lateral edge and the cylindrical segment defined by the internal peripheral edge have a smooth transition.
[0012] It is understood that the said smooth transition makes it possible to eliminate the sharp edges on the horizontal and vertical edges of the hemi-annular parts of the neck ring, thus preventing the protruding parts of the neck ring from hooking the preform and causing it to rotate around its longitudinal axis of revolution and / or pinching it during the preform placement phase in the mold.
[0013] Said smooth transition extends in whole or in part between the distal edge of the shoulder and the internal peripheral edge of said at least one hemi-annular part.
[0014] Advantageously, said smooth transition consists of a leave of absence.
[0015] Said fillet is convex, the convexity of said fillet being oriented towards the face upper part of the hemi-annular portion of the neck ring.
[0016] Preferably, the radius of curvature of the convexity of the fillet is between 0.05 and 2 mm and, preferably, the radius of curvature of the convexity of the fillet is 0.5 mm.
[0017] According to one embodiment, said smooth transition consists of a chamfer.
[0018] Furthermore, said chamfer has an angle between 30 and 60° and, preferably, said chamfer has an angle of 45°. Brief description of the drawings
[0019] Other advantages and features will become clearer from the following description of several embodiments, given by way of non-limiting examples, of the neck ring according to the invention, with reference to the accompanying drawings in which:
[0020] [Fig. 1] is a perspective view of a semi-annular portion of the neck ring according to the invention,
[0021] [Fig.2] is a perspective view of a detail of the hemi-annular part of the neck ring according to the invention shown in [Fig.1]. Method of embodying the invention
[0022] In the remainder of the description of the neck ring according to the invention, the same numerical references designate the same elements. Furthermore, the different views are not necessarily drawn to scale.
[0023] Furthermore, the set of the two semicylindrical parts of the mold on which the neck ring according to the invention is fixed, of the blow nozzle and of all the other constituent elements of the blower are not described in detail; In this regard, reference may be made to European patent EP0989931 in the name of the applicant.
[0024] With reference to [Fig. 1] on which a single hemi-annular part 1 of a so-called neck ring according to the invention is shown, the neck ring being made up of two hemi-annular parts suitable for being mounted at the upper end of each half-mold of a blow mold, not shown in the figures, each hemi-annular part 1 of said neck ring comprises an internal hemi-circular peripheral edge 2 forming a cylindrical segment which extends perpendicularly to the upper 3 and lower 4 faces of the hemi-annular part 1, an external hemi-circular peripheral edge 5 and two diametrically opposed lateral edges 6, said lateral edges 4 connecting the ends of the external peripheral edge 3 and internal peripheral edge 2.
[0025] Furthermore, each hemi-annular portion 1 of said neck ring also comprises a planar hemi-annular shoulder 7 extending along the inner peripheral edge 2, from one lateral edge 6 to the other. This planar hemi-annular shoulder 7 is adapted to receive the collar of a neck of a preform, the lower face of the collar bearing against said planar hemi-annular shoulder 7 during the preform placement phase in the mold.
[0026] Furthermore, in order to allow the fixing of each hemi-annular part 1 respectively on a half-mold of a mold, each hemi-annular part 1 has three through holes 8 suitable for receiving a screw, not shown in the figures, the upper end of each half-mold having three tapped holes extending in line with said through holes 8 and suitable for cooperating with said screws.
[0027] With reference to figures 1 and 2, at least the edge between the planar hemi-annular shoulder 7 and the lateral edges 6 of at least one of the hemi-annular parts 1 and the edge between the lateral edges 6 and the cylindrical segment defined by the internal peripheral edge 2 have a smooth transition 9.
[0028] It is understood that said smooth transition 9 makes it possible to eliminate the sharp edges on the horizontal and vertical edges of the hemi-annular parts 1 of the neck ring, thus preventing the protruding parts of the neck ring from hooking the preform and causing it to rotate around its longitudinal axis of revolution and / or pinching it during the preform placement phase in the mold.
[0029] Said smooth transition 9 extends in whole or in part between the distal edge of the flat hemi-annular shoulder 7 and the internal peripheral edge 2 of said at least a part hemi-annular 1. In this particular embodiment, said smooth transition 9 extends from the planar hemi-annular shoulder 7 to the lower face 4 of the hemi-annular part 1; However, said smooth transition 9 could extend only partially between the planar hemi-annular shoulder 7 and the lower face 4 of the hemi-annular part 1, stopping for example a few tenths of a millimeter from the lower face 4 of the hemi-annular part 1, without going out of the scope of the invention.
[0030] Advantageously, said smooth transition 9 consists of a chamfer which has an angle between 30 and 60° and, preferably, said chamfer has an angle of 45°.
[0031] According to an embodiment not shown in the figures, said smooth transition 9 consists of a fillet.
[0032] Said fillet is convex, the convexity of said fillet being oriented towards the upper face 3 of the hemi-annular part 1 of the collar ring.
[0033] Preferably, the radius of curvature of the convexity of the fillet is between 0.05 and 2 mm and, preferably, the radius of curvature of the concavity of the fillet is 0.5 mm.
[0034] It goes without saying that said smooth transition 9 may consist of any other form well known to a person skilled in the art, such as a rounded shape for example, and that said smooth transition 9 may be obtained by any appropriate means such as by machining or by additive manufacturing for example without going out of the scope of the invention.
[0035] Finally, it is quite clear that the examples just given are only particular illustrations and in no way limiting as to the fields of application of the invention.
Claims
Demands
1. A neck ring for a blow mold consisting of two semi-annular parts (1), each semi-annular part (1) of said neck ring comprising an internal semi-circular peripheral edge (2) forming a cylindrical segment extending perpendicularly to the plane of the upper face (3) of the semi-annular part (1), an external semi-circular peripheral edge (5) and two diametrically opposed lateral edges (6), said lateral edges (6) connecting the ends of the external (5) and internal (2) peripheral edges, each semi-annular part (1) of said ring also comprising a planar semi-annular shoulder (7) extending along the internal peripheral edge (2),from one lateral edge (6) to the other characterized in that at least the edge between the flat hemi-annular shoulder (7) and the lateral edges (6) of at least one of the hemi-annular parts (1) and the edge between the lateral edge (6) and the cylindrical segment defined by the internal peripheral edge (2) have a smooth transition (9).
2. Neck ring according to claim 1 characterized in that said smooth transition (9) extends in whole or in part between the distal edge of the flat hemi-annular shoulder (7) and the inner peripheral edge (2) of said at least one hemi-annular part (1).
3. Collar ring according to any one of claims 1 or 2 characterized in that said smooth transition (9) consists of a fillet.
4. Neck ring according to claim 3 characterized in that said fillet is convex, the convexity of said fillet being oriented towards the upper face (3) of the hemi-annular part (1) of the neck ring.
5. Neck ring according to claim 4 characterized in that the radius of curvature of the convexity of the fillet is between 0.05 and 2 mm.
6. Neck ring according to claim 5 characterized in that the radius of curvature of the convexity of the fillet is 0.5 mm.
7. Neck ring according to any one of claims 1 or 2 characterized in that said smooth transition (9) consists of a chamfer.
8. Neck ring according to claim 7 characterized in that said chamfer (9) has an angle between 30 and 60°.
9. Collar ring according to claim 8 characterized in that said chamfer (9) has an angle of 45°.