Abstract: An improved structure for sealing a through-hole formed in a plastic hollow product when mounting a component such as a sensor on the product is provided. A cylindrical section is provided in a peripheral wall of the plastic hollow product as projecting radially outwardly from the peripheral wall and an inner circumferential surface of the cylindrical section defines the through-hole for communication between the interior and the exterior of the product. A sensor component is mounted with its sensor portion extending through the through-hole and an O-ring is disposed between the sensor portion and the inner circumferential surface of the cylindrical section which is backed by a component mounting member.

Abstract: A method for manufacturing a hollow plastic product. The method includes the steps of forming a reinforce member in a desired shape having a defined welding surface formed with a first hole by injection molding; forming a hollow main body by blow molding using said reinforce member as an insert, thereby having said reinforce member integrally formed with said hollow main body and having a portion of said hollow main body extended into said first hole in the shape of a mesa when blow-molded; thermally welding a top end surface of a connector pipe to said welding surface and also to a top surface of said mesa shaped portion; and forming a second hole in said top surface of said mesa shaped portion to be aligned with said second hole, thereby forming a fluidic communication passage between an interior of said hollow main body and an interior of said connector pipe.

Abstract: An improved structure for sealing a through-hole formed in a plastic hollow product when mounting a component such as a sensor on the product is provided. A cylindrical section is provided in a peripheral wall of the plastic hollow product as projecting radially outwardly from the peripheral wall and an inner circumferential surface of the cylindrical section defines the through-hole for communication between the interior and the exterior of the product. A sensor component is mounted with its sensor portion extending through the through-hole and an O-ring is disposed between the sensor portion and the inner circumferential surface of the cylindrical section which is backed by a component mounting member.

Abstract: A hollow plastic product including a hollow main body, a reinforce member and a connector pipe is provided. Such a hollow plastic product is, for example, used advantageously as a component of an air-intake system or fuel supply system of an automobile. In one example, the hollow main body is a duct, hose or tube extending over a length, and the reinforce member is ring-shaped so that it extends around a circumference of an outer surface of the hollow main body. The reinforce member is manufactured by injection molding and is used as an insert when blow-molding the hollow main body, so that the reinforce member is integrally formed with the main body. The reinforce member has a defined welding surface formed with a first hole, to which one end surface of a connector pipe is thermally welded. Then the hollow main body is formed with a second hole in alignment with the first hole, thereby defining a fluidic communication between the hollow main body and the connector pipe.

Abstract: A hollow plastic product including a hollow main body, a reinforce member and a connector pipe is provided. Such a hollow plastic product is, for example, used advantageously as a component of an air-intake system or fuel supply system of an automobile. In one example, the hollow main body is a duct, hose or tube extending over a length, and the reinforce member is ring-shaped so that it extends around a circumference of an outer surface of the hollow main body. The reinforce member is manufactured by injection molding and is used as an insert when blow-molding the hollow main body, so that the reinforce member is integrally formed with the main body. The reinforce member has a defined welding surface formed with a first hole, to which one end surface of a connector pipe is thermally welded. Then the hollow main body is formed with a second hole in alignment with the first hole, thereby defining a fluidic communication between the hollow main body and the connector pipe.

Abstract: A multi-layered plastic pipe particularly suitable for use as an intake manifold of an internal combustion engine is provided. The present pipe includes a hollow plastic core, at least one spacer member provided on the hollow plastic core and an outer layer integrally provided on the outer peripheral surface of the hollow plastic core excepting the spacer member. The spacer member is preferably formed from a plastic material, and the outer layer is also formed from a plastic material. There is also provided a method for manufacturing a multi-layered plastic pipe using a spacer member to prevent a hollow plastic core placed in a mold cavity from being deformed when a molted plastic material is supplied into the mold cavity under pressure.

Abstract: A spiral bellows structure having a longitudinal axis includes at least one peak portion extending spirally around and along the longitudinal axis and at least one valley portion extending in parallel with the peak portion to thereby define a flow passage. The spiral bellows structure has a reduced flow resistance because of its tendency to suppress turbulence and eddies while allowing to keep the original characteristics, such as flexibility, of a straight bellows structure substantially unchanged.

Abstract: A method and apparatus for manufacturing a hollow plastic product is provided. In accordance with one aspect, into a mold half having a tubular groove portion and a projecting groove portion which projects outwardly from the tubular groove section is supplied a parison into the tubular groove portion and a clump of molding material into the projecting groove portion, and when blow molding is carried out by introducing a pressurized gas into the parison, the clump becomes integrated with the parison thereby providing a plastic product of unitary structure. In accordance with another aspect of the present invention, a parison extrusion nozzle is provided with at least two passages each of which is connected, preferably through a valve, to a corresponding dispensing unit for dispensing a desired molding material. A control unit is provided as connected to each of the dispensing units to control the supply of molding material so that there is obtained a parison having regions of different molding materials.

Abstract: A method for manufacturing a multilayered plastic pipe particularly suitable for use as an intake manifold of an internal combustion engine is provided. The method includes the steps of forming a hollow plastic core, providing at least one spacer member on the hollow plastic core, supplying a molten plastic material into a mold cavity and applying a compression force to the material inside the cavity to form an outer layer integrally on the outer peripheral surface of the hollow plastic core. The spacer member prevents the hollow plastic core in the mold cavity from being deformed when a molten plastic material is supplied into the mold cavity under pressure.

Abstract: A method and apparatus for manufacturing a hollow plastic product is provided. In accordance with one aspect, into a mold half having a tubular groove portion and a projecting groove portion which projects outwardly from the tubular groove section is supplied a parison into the tubular groove portion and a clump of molding material into the projecting groove portion, and when blow molding is carried out by introducing a pressurized gas into the parison, the clump becomes integrated with the parison thereby providing a plastic product of unitary structure. In accordance with another aspect of the present invention, a parison extrusion nozzle is provided with at least two passages each of which is connected, preferably through a valve, to a corresponding dispensing unit for dispensing a desired molding material. A control unit is provided as connected to each of the dispensing units to control the supply of molding material so that there is obtained a parison having regions of different molding materials.

Abstract: A method and apparatus for manufacturing a multi-layer plastic product comprised of a hollow plastic core and an outer plastic layer formed on the core are provided. A mold has a plurality of segments and is provided with a plurality of supply ports arranged in a desired pattern. The mold is assembled with the hollow plastic core located in a mold cavity, and, then, a molten plastic material is supplied into the mold cavity through the plurality of supply ports. Then, the mold is set in its clamped condition to carry out shaping of the molten plastic material into the outer layer having a desired shape. Since the molten plastic material is supplied through a plurality of supply ports, the pressure inside the mold cavity during supply and shaping steps is maintained at a relatively low pressure level, preferably 200 kg/cm.sup.2, which is much lower than an ordinary pressure level used in injection molding.

Abstract: A hollow plastic product having a sound/noise attenuating function is provided. The product includes a duct (1) defining a flow passage and extending over a length along a longitudinal axis, a resonator (1b) having an internal chamber (1b') and a connector (1c) which establishes a fluidic communication between the flow passage of duct (1) and the internal chamber (1b') of resonator (1b). The resonator (1b) serves to absorb or attenuate sound/noise created by the fluid flowing through the flow passage. The product is manufactured from the same parison at the same time and thus has a unitary structure. An improved method for manufacturing such a hollow plastic product is also provided.

Abstract: A multi-layered plastic pipe particularly suitable for use as an intake manifold of an internal combustion engine is provided. The present pipe includes a hollow plastic core, at least one spacer member provided on the hollow plastic core and an outer layer integrally provided on the outer peripheral surface of the hollow plastic core excepting the spacer member. The spacer member is preferably formed from a plastic material, and the outer layer is also formed from a plastic material. There is also provided a method for manufacturing a multi-layered plastic pipe using a spacer member to prevent a hollow plastic core placed in a mold cavity from being deformed when a molted plastic material is supplied into the mold cavity under pressure.

Abstract: A method and apparatus for manufacturing a hollow plastic product is provided. In accordance with one aspect, into a mold half having a tubular groove portion and a projecting groove portion which projects outwardly from the tubular groove section is supplied a parison into the tubular groove portion and a clump of molding material into the projecting groove portion. When blow molding is carried out by introducing a pressurized gas into the parison, the clump becomes integrated with the parison thereby providing a hollow plastic product of unitary structure. In accordance with another aspect of the present invention, a parison extrusion nozzle is provided with at least two passages each of which is connected, preferably through a valve, to a corresponding dispensing unit for dispensing a desired molding material. A control unit is provided as connected to each of the dispensing units to control the supply of molding material so that there is obtained a parison having regions of different molding materials.

Abstract: A method for producing a plastic product including an axially extending portion, such as a duct or pipe, and a radially extending portion, such as a flange or bracket. A parison is placed in a first mold cavity defined in a mold and blow molded to form the axially extending portion, and then a movable mold segment is moved to a retracted position to define a second mold cavity adjacent to a part of an outer peripheral surface of the axially extending portion thus formed. Then, a second molted plastic material is supplied into the second mold cavity and the movable mold segment is again moved to another predetermined position to pressurize the second plastic material to thereby form a radially extending portion. The resulting hollow plastic product is extremely high in structural integrity between the axially and radially extending portions.

Abstract: A composite parison generally cylindrical in shape and including two or more plastic materials different in characteristic is formed. Using this composite parison, a hollow plastic product of any desired shape having a locally different characteristic, such as in softness, heat-resistance or wear-resistance, can be manufactured with ease, for example, by conventional blow molding.

Abstract: An apparatus for manufacturing a hollow plastic product is provided. In accordance with one aspect, into a mold half having a tubular groove portion and a projecting groove portion which projects outwardly from the tubular groove section is supplied a parison into the tubular groove portion and a clump of molding material into the projecting groove portion. When blow molding is carried out by introducing a pressurized gas into the parison, the clump becomes integrated with the parison thereby providing a hollow plastic product of unitary structure. In accordance with another aspect of the present invention, a parison extrusion nozzle is provided with at least two passages each of which is connected, preferably through a valve, to a corresponding dispensing unit for dispensing a desired molding material. A control unit is provided as connected to each of the dispensing units to control the supply of molding material so that there is obtained a parison having regions of different molding materials.

Abstract: Apparatus for molding plastic products of virtually any complicated configuration is provided. When a parison is extruded out of a nozzle, a separating agent, preferably oil, is supplied into the parison as a lubricant. Since a thin film of the separating agent is formed on the inside surface of the parison, portions of the inside surface do not stick together even if they are brought into contact from some reasons. This insures to mold a plastic product of a very complex configuration. Use of a separating agent also allows to form sheet-type products by dividing the parison into several sections as desired. This is a very efficient way of forming sheet-type products since at least two may be formed at the same time.

Abstract: A method and apparatus for manufacturing a hollow plastic product is provided. In accordance with one aspect, into a mold half having a tubular groove portion and a projecting groove portion which projects outwardly from the tubular groove section is supplied a parison into the tubular groove portion and a clump of molding material into the projecting groove portion. When blow molding is carried out by introducing a pressurized gas into the parison, the clump becomes integrated with the parison thereby providing a hollow plastic product of unitary structure. In accordance with another aspect of the present invention, a parison extrusion nozzle is provided with at least two passages each of which is connected, preferably through a valve, to a corresponding dispensing unit for dispensing a desired molding material. A control unit is provided as connected to each of the dispensing units to control the supply of molding material so that there is obtained a parison having regions of different molding materials.

Abstract: A method and apparatus for molding plastic products of virtually any complicated configuration is provided. When a parison is extruded out of a nozzle, a separating agent, preferably oil, is supplied into the parison as a lubricant. Since a thin film of the separating agent is formed on the inside surface of the parison, portions of the inside surface do not stick together even if they are brought into contact from some reasons. This insures to mold a plastic product of a very complex configuration. Use of a separating agent also allows to form sheet-type products by dividing the parison into several sections as desired. This is a very efficient way of forming sheet-type products since at least two may be formed at the same time.