Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60B—VEHICLE WHEELS; CASTORS; AXLES FOR WHEELS OR CASTORS; INCREASING WHEEL ADHESION
  • B60B5/00—Wheels, spokes, disc bodies, rims, hubs, wholly or predominantly made of non-metallic material
  • B60B5/02—Wheels, spokes, disc bodies, rims, hubs, wholly or predominantly made of non-metallic material made of synthetic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
  • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
  • B29C45/17—Component parts, details or accessories; Auxiliary operations
  • B29C45/1703—Introducing an auxiliary fluid into the mould
  • B29C45/1704—Introducing an auxiliary fluid into the mould the fluid being introduced into the interior of the injected material which is still in a molten state, e.g. for producing hollow articles
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/21—Circular sheet or circular blank
  • Y10T428/218—Aperture containing

Definitions

• the present invention relates to the field of production of hollow parts in synthetic material, by injection, in particular of wheels, flywheels and all other hollow parts forming a circular ring or not, and relates to a method of manufacturing a such annular part of hollow section.
• the invention also relates to an annular part of hollow section obtained by implementing this method.
• the realization of this type of part meets a technical specification taking into account the efforts which the part must be able to resist, as well as the aesthetic criteria which it must respect.
• the hollow wheels of children's tricycles are generally produced according to a rotational molding technique consisting in introducing a polymer powder into a cold mold which is then rotated and heated. This results in a flow of the molten material along the wall of the mold so as to form a complete part.
• JP-A-2002 018906 are various gas injection methods, which are only applicable to the manufacture of small diameter wheels.
• a fundamental difference between the methods described in this document and the method according to the present invention lies in the use of the spokes of the parts to be produced to bring the fluid, such as gas, into the tread.
• the supply of the fluid, such as gas is carried out by complex means at different locations on the rim.
• the object of the present invention is to overcome these drawbacks by proposing a method of manufacturing wheels, flywheels and all other annular parts, the wall thickness of the annular part of which is relatively small, this manufacture being carried out in a single operation. molding.
• the method of manufacturing plastic parts with a hollow annular section, produced by a prior injection of molten synthetic material into a mold, followed by the injection of a pressurized fluid intended to repel the molten material against walls of the mold, while completing the filling of the imprint is characterized in that it consists essentially in carrying out the injection of molten synthetic material, at the level of the nose or hub, by means of an orifice provided for this effect in the mold and in that the injection of a fluid is carried out, near the nose or hub, through at least one orifice provided in the core allowing the realization of the zone of guidance of the axis of rotation .
• FIG. 1 is a side elevational view and partially in section of a hollow annular section of synthetic material obtained by implementing the method according to the invention
• Figure 2 is a sectional view along AA of Figure 1. According to to the invention and as shown more particularly, by way of example, FIGS.
• a part 1 comprising a hollow annular section 2 connected to the hub or nose 3 by one or more spokes or ribs 4 arranged at regular intervals and integrated or not in a web 5.
• the injection of fluid is carried out through the core allowing the realization of the guide zone 10 of the axis of rotation, the fluid being distributed equitably in each of the preferred directions determined by the ribs or spokes 4.
• the part 1 is provided with ribs or spokes 4 connecting the nose or hub 3 to the annular section 2 arranged at regular intervals or not.
• the bubbles formed by the injection of fluid from the core thus realize an intimate application of the synthetic material against the corresponding walls of the mold, namely those delimiting the ribs or spokes 4 and the hollow annular section 2, these bubbles expanding perfectly balanced in the part of the mold corresponding to the hollow annular section 2 by forming, between two bubbles emanating from two different ribs or spokes 4, a partition wall 7 ( Figure 1). Indeed, it should be remembered that theoretically two bubbles cannot perforate, so that it necessarily forms between two bubbles deforming a viscous material a wall or a mat of material determining the partition walls 7 which constitute a kind of ribs transverse reinforcement inside the hollow annular section 2.
• the manufacturing process according to the invention therefore allows, by an appropriate dosage of the injection of synthetic material and by the injection of fluid by l intermediary of the injection core, to achieve relatively low wall thicknesses of the ribs or spokes and of the hollow annular section, while ensuring good rigidity of the latter, that is to say avoiding its deformation under load .
• a part with a diameter of 250 mm comprising a hollow annular section with a height of between 18 mm and 24 mm will have a veil with a thickness of 3 mm and ribs with a width of the order of 12 mm, while the wall thickness of the hollow annular section will be of the order of 3 to 5 mm.
• the number of spokes or ribs 4 provided in the web 5 and forming a stiffening support for said web 5, as well as the thickness of the latter are a function of the external dimensions of the part and the desired thickness of the section hollow annular.
• the ribs 4 have a circular section and thus form a mechanically very solid reinforcement.
• the plastic part thus obtained is provided, by overmolding, with a covering strip 8 made of a soft synthetic material, such as synthetic rubber or any other material capable of fulfilling the same office.
• the thickness of this coating strip 8 is between 3 mm and 5 mm.
• the invention also relates to a plastic part of hollow annular section, which is characterized in that it is in one piece and has a hollow annular section 2 provided with hollow sections delimited by transverse walls 7, these hollow sections being connected each with a corresponding hollow section delimited in a rib or a radius 4 and / or in a veil 5.
• the part 1 can be provided, on at least one side of its hub or nose 3 with a means 9 for guidance and snap-fastening on a support.
• This means 9 may be in the form of a stud snapped into an orifice 11 provided for this purpose in the hub or nose 3. It is thus possible to achieve the axial positioning of the part 1 along its axis.
• the hub or nose 3 is thus retained in translation and simultaneously guided in rotation.
• Part 1 according to the invention is more particularly intended to equip movable materials such as urban containers, handling carts, as well as small maintenance devices such as lawn mowers or even wheels for children's bikes. or stroller wheels for carrying children. This list is however by no means exhaustive.
• the invention it is possible to produce, by fluid assisted injection, plastic parts whose annular section is hollow and have walls of small thickness, while being rigid enough to withstand the loads to which they are normally submitted. As a result, for the same diameter, the parts thus obtained are lighter and therefore require the use of less synthetic material, so that their cost price can be reduced accordingly.
• the invention is not limited to the embodiment described and shown in the accompanying drawing. Modifications remain possible, in particular from the point of view of the constitution of the various elements or by substitution of technical equivalents, without thereby departing from the scope of protection of the invention.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Materials Engineering (AREA)
• Manufacturing & Machinery (AREA)
• Moulds For Moulding Plastics Or The Like (AREA)
• Injection Moulding Of Plastics Or The Like (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

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• 2003
  • 2003-10-27 US US10/577,467 patent/US20070134455A1/en not_active Abandoned
  • 2003-10-27 AU AU2003285468A patent/AU2003285468A1/en not_active Abandoned
  • 2003-10-27 EP EP03778469A patent/EP1677962A1/de not_active Withdrawn
  • 2003-10-27 CA CA002543850A patent/CA2543850A1/fr not_active Abandoned
  • 2003-10-27 WO PCT/FR2003/003187 patent/WO2005051631A1/fr active Application Filing

Non-Patent Citations (1)

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