# US 6,733,272 B1 · Molding unit comprising improved compensating means and extrusion-blow molding machine equipped therewith > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,733,272 B1 - Document ID: US6733272B1 - Status: Granted - Kind: B1 - Application number: 09/914,649 - Filed: 2002-01-10 - Granted: 2004-05-11 - Earliest claimed: 1999-03-08 - Assignees: Sidel - Inventors: Philippe Derouault; Eric Lemaistre - Web page: https://patentgrep.com/patent/US6733272B1 ## CPC - B29C 49/56: Opening, closing or clamping means - B29C 49/04: Extrusion blow-moulding - B29C 2033/205: {mould clamping by membranes, e.g. inflatable membranes or cushions} - B29C 2049/4864: {Fixed by a special construction to the mould half carriers, e.g. using insulating material between the mould and the mould half carrier} - B29C 2049/5633: {Pneumatic} - B29C 2049/5635: {Avoiding mould deformation} - 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 (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00) ## Abstract The invention proposes a molding unit comprising a mold in two parts, each mold-half (12) being borne by a support (17), of the type in which the two supports can be moved between an open position and a closed position, in which the supports are connected to each other by locking means, and of the type in which the molding unit comprises fluid pressure compensating means that push transversely at least one of the mold-halves (12) toward the other, characterized in that the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (17). ## Claims ### Claim 1 A molding unit for an extrusion-blow molding machine for articles made of thermoplastic material, of the type in which the molding unit (10) comprises a mold in two parts, each mold-half (12, 14) being borne by a support (16, 18), of the type in which the two supports (16, 18) can be moved relative to each other between an open position in which the two mold-halves (12, 14) are transversely separated from each other to allow the insertion of a parison in a cavity (20) delimited between the two mold-halves (12, 14), and a closed position in which the front faces of the two mold-halves (12, 14) are pressed against each other, and in which the supports (16, 18) are connected to each other by locking means, and of the type in which the molding unit (10) comprises, between at least one of the mold-halves (12) and the associated support (16), fluid pressure compensating means that push the mold-half (12) transversely from a retracted position to an advanced position, toward the other mold-half (14), characterized in that the mold-half (12) has controlled pull-back means (48) for pulling back the mold-half (12) to its retracted position. ### Claim 2 (depends on 1) The molding unit according to claim 1, characterized in that the pull-back means comprise an auxiliary inflatable flexible cushion (48). ### Claim 3 (depends on 2) The molding unit according to claim 2, characterized in that the pull-back means comprise a bracket (34) that is placed on the outer side of the support (16) and which has, at its two opposite ends, connecting pins (44) that extend through oblong holes (46) made in the side faces (21) of the support to connect to the mold-half (12), and in that the auxiliary cushion (48) is interposed between the bracket (34) and a rear face of the support (16). ### Claim 4 (depends on 3) The molding unit according to claim 3, characterized in that the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16). ### Claim 5 (depends on 4) The molding unit according to claim 4, characterized in that, in transverse projection, the cushion (30) extends in such a way as to cover substantially the entire surface of the transverse projection of the mold-half (12). ### Claim 6 (depends on 5) The molding unit according to claim 5, characterized in that, when the supports (16, 18) are in the closed position, the molding unit (10) is ready for the blow-molding, and in that the inflatable cushion (30) controls the movement of the mold-half (12) from its retracted position to its advanced position after the two supports (16, 18) are locked in the closed position. ### Claim 7 (depends on 1) The molding unit according to claim 1, characterized in that, the mold-halves (12, 14) are furnished with pre-cut means which, when the mold-half (12) is in the advanced position, perform a pre-cut of the parison depending on the contour of the article to be formed. ### Claim 8 (depends on 1) An extrusion-blow forming machine, characterized in that it comprises at least one molding unit (10) in accordance with claim 1. ### Claim 9 (depends on 1) The molding unit according to claim 1, characterized in that the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16). ### Claim 10 (depends on 1) The molding unit according to claim 1, characterized in that: the pull-back means comprise an auxiliary inflatable flexible cushion (48); and the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16). ### Claim 11 (depends on 1) The molding unit according to claim 1, characterized in that: the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16); and in transverse projection, the cushion (30) extends in such a way as to cover substantially the entire surface of the transverse projection of the mold-half (12). ### Claim 12 (depends on 1) The molding unit according to claim 1, characterized in that: the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16); and when the supports (16, 18) are in the closed position, the molding unit (10) is ready for the blow-molding, and in that the inflatable cushion (30) controls the movement of the mold-half (12) from its retracted position to its advanced position after the two supports (16, 18) are locked in the closed position. ### Claim 13 (depends on 1) The molding unit according to claim 1, characterized in that: the pull-back means comprise an auxiliary inflatable flexible cushion (48); the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16); and in transverse projection, the cushion (30) extends in such a way as to cover substantially the entire surface of the transverse projection of the mold-half (12). ### Claim 14 (depends on 1) The molding unit according to claim 1, characterized in that: the pull-back means comprise an auxiliary inflatable flexible cushion (48); the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16); and when the supports (16, 18) are in the closed position, the molding unit (10) is ready for the blow-molding, and in that the inflatable cushion (30) controls the movement of the mold-half (12) from its retracted position to its advanced position after the two supports (16, 18) are locked in the closed position. ### Claim 15 (depends on 1) The molding unit according to claim 1, characterized in that: the pull-back means comprise an auxiliary inflatable flexible cushion (48); the pull-back means comprise a bracket (34) that is placed on the outer side of the support (16) and which has, at its two opposite ends, connecting pins (44) that extend through oblong holes (46) made in the side faces (21) of the support to connect to the mold-half (12), and in that the auxiliary cushion (48) is interposed between the bracket (34) and a rear face of the support (16); the fluid pressure compensating means are realized in the form of an inflatable flexible cushion (30) interposed between one rear face of the mold-half (12) and one front face of the associated support (16); and when the supports (16, 18) are in the closed position, the molding unit (10) is ready for the blow-molding, and in that the inflatable cushion (30) controls the movement of the mold-half (12) from its retracted position to its advanced position after the two supports (16, 18) are locked in the closed position.