Blow molding device for producing thermoplastic containers

Details Blow molding device for producing thermoplastic containers Blow molding device for producing thermoplastic containers

1997-10-17

1999-10-19

Davis, Robert

Plastic article or earthenware shaping or treating: apparatus

With apparatus assembly or dismantling means or with idle part

For extrusion or injection type shaping means

425195, 425522, 425541, 249102, B29C 4956, B29C 3330

Patent

active

059685603

DESCRIPTION:

BRIEF SUMMARY
The present invention relates to improvements made to devices making it possible to manufacture containers, in particular bottles, made of a thermoplastic by blow molding or stretch-blow molding of a preheated preform, the said device including at least one mold consisting of two half-molds respectively supported by two mold carriers which can move one with respect to the other.
It is common practice for the half-molds to be removably fixed to the respective mold carriers so that the said half-molds can be replaced or changed should they become damaged and/or worn and, above all, should containers of different shapes and/or sizes be manufactured, without it being necessary to replace the entire molding device.
However, such an arrangement is still far from being to the complete satisfaction of users. This is because each half-mold is heavy (for example about 25 to 30 kg for a steel mold): the fixing means must be able to support this weight and comprise many nut-and-bolt and/or screw connections; furthermore, each half-mold must be handled by several people and/or by means of a hoist, thereby requiring a suitable installation above the manufacturing device. Each half-mold is equipped with means for the circulation of one or more fluids for the cooling and/or heating of the walls of the impression: replacing each half-mold is accompanied by disconnecting, followed by reconnecting, of the corresponding fluid connections, all operations requiring time.
It is also necessary to add an economic consideration regarding the actual construction of each half-mold. The impression serving for pressure molding the final container must have a perfectly polished surface finish, to which, furthermore, the hot thermoplastic must not adhere: it is therefore necessary for the impression to be made of a suitable metallic material (for example stainless steel) which, moreover, may differ depending on the thermoplastic employed. Given the monobloc structure of the half-mold, it is therefore the totality of each half-mold which must be made of this suitable metallic material, this being a special and therefore expensive material, while the rear part of the half-molds merely fulfills a mechanical strength function, giving the mold rigidity and non-deformability, for which rear part a more ordinary, and therefore less expensive, material could be perfectly suitable.
The object of the invention is therefore essentially to remedy, as far as is possible, the drawbacks of the currently known manufacturing devices and to provide an improved device which allows quick and simple changing of the molding impressions in order to make it easier to adapt the device to the manufacture of various containers, and the improved structure of which device is, at the end of the day, less expensive than that of the current devices while still maintaining the same strength and non-deformability properties.
To these ends, a device for manufacturing thermoplastic containers, as mentioned in the preamble, is essentially characterized, being designed in accordance with the invention, in that each half-mold comprises a shell holder supported by the respective mold carrier and a shell which is provided with a half-impression of the container to be obtained and which can be removably fastened to its shell holder by quick-fixing means, the shell and the shell holder being of complementary shapes in order to be in at least partial mutual contact, with thermal conduction, while the pipes and connections for the circulation of cooling and/or heating fluids, and optionally the members for guiding the half-molds in order to close the mold, as well as the pressure-compensating means for maintaining the sealed closure of the mold during blow molding, are provided exclusively in the shell holder.
By virtue of this arrangement, the part of the half-mold corresponding to the impression, which may be economically made of a suitable and relatively expensive material, and the rear part of the half-mold, which provides rigidity and mechanical strength and which may be made

REFERENCES:
patent: 467881 (1892-01-01), Fisher
patent: 1409591 (1922-03-01), Schavoir
patent: 3191225 (1965-06-01), Polka
patent: 3753641 (1973-08-01), Turner et al.
patent: 3784344 (1974-01-01), Korsch
patent: 3871611 (1975-03-01), Taketa
patent: 4072456 (1978-02-01), Appel et al.
patent: 5262116 (1993-11-01), Von Holdt, Sr.
patent: 5288222 (1994-02-01), Wieser
patent: 5332384 (1994-07-01), Abramat
patent: 5346386 (1994-09-01), Albrecht et al.
patent: 5358396 (1994-10-01), Giesen
"Quick-change systems add to blow molders' market reach", by Patrick A. Toensmeier, Modern Plastics International, Aug. 1991 (pp. 30-31).
Patent Abstracts of Japan, vol. 12, No. 286 (M-727), Aug. 5, 1988, (Abstract of Japanese reference 63-062,710 dated Mar. 19, 1988).

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