Molding unit for manufacturing containers from preforms made of plastic material

Abstract

A molding unit (10) for manufacturing preforms (100) made of plastics material, includes at least one HR-type mold (10), a nozzle (14) including at least a nozzle body (28) and a nozzle orifice (30) incorporating a preform (100) stabilizer (34) that forms with a tubular member (40) a mobile assembly that is able to slide axially relative to the nozzle orifice (30) between at least a top position and a bottom position, wherein the tubular member (40) is guided so as to slide axially with respect to the nozzle body (28) by at least one guiding element (46) which is interposed radially between the nozzle body (28) and the tubular inlet member (40), and the stabilizer (34), fixed to the tubular member (40), is guided with respect to the nozzle body (28) only by way of the at least one guiding element (46).

Claims

1. A molding unit (10) for the manufacturing of containers by blow molding or by stretch blow molding from preforms (100) made of plastic material comprising a neck (104) equipped with a rim (106) circumferentially delimiting an opening (102) for access inside said preform (100), with said molding unit (10) comprising at least: a mold (12) that comprises at least two half-molds (16) mounted to move between at least one open position and one closed position in which the joined half-molds (16) delimit an upper surface (18) comprising an orifice (20) that empties into a molding cavity (22) delimited at least by a molding impression (24) of each half-mold, a heating device (26) associated with said mold (12), the heating device (26) arranged to heat each molding impression of each half mold, the mold for forming heat resistant containers, a nozzle (14) comprising at least one nozzle body (28) and one nozzle nose (30) that is mounted to move axially in relation to said nozzle body (28) between a raised position above the mold (12) and a lowered blow-molding position, with said nozzle nose (30) being controlled axially in movement between said raised and lowered positions by an actuating device (32), and a stabilizer (34) comprising a support surface (36) designed to work with the rim (106) of the neck (104) and a blocking device (38) in position designed to be inserted inside the neck (104), with said stabilizer (34) being housed inside the nozzle nose (30) and forming with a tubular element (40) for intake of at least one pressurized fluid a movable apparatus that, driven with said nozzle nose (30), is able to slide axially relative to said nozzle nose (30) between at least one top position and one bottom position, wherein the tubular element (40) is guided by axial sliding in relation to the nozzle body (28) by at least one guide device (46) that is inserted radially between said nozzle body (28) and said tubular intake element (40), and the stabilizer (34), attached to said tubular element (40), is guided in relation to the nozzle body (28) only by said at least one guide device (46).

2. The molding unit according to claim 1, wherein said stabilizer (34) is made of plastic material.

3. The molding unit according to claim 1, wherein the actuating device (32) associated with said nozzle nose (30) includes a linear motor.

4. The molding unit according to claim 1, wherein said at least one guide device (46) is carried by the nozzle body (28).

5. The molding unit according to claim 1, wherein said at least one guide device (46) includes at least one pair of guide rings (48), axially superposed in one another.

6. The molding unit according to claim 1, wherein the stabilizer (34) is attached in a detachable manner to the tubular intake element (40) by an attachment device (50) constituted by at least one elastically deformable element.

7. The molding unit according to claim 1, wherein the nozzle (14) comprises a return device (42) that returns the stabilizer (34) towards the bottom position that are arranged axially above said at least one guide device (46).

8. The molding unit according to claim 7, wherein the return device (42) includes a compression spring whose upper end axially rests on a radial support surface (54) of the nozzle body (28).

9. The molding unit according to claim 7, wherein the return device (42) includes a compression spring whose lower end axially rests on a radial support surface (56) that comprises an annular collar (58) that is integral with the tubular intake element (40).

10. The molding unit according to claim 1, wherein the nozzle (14) comprises at least a stop device (62) that, determining the bottom position, includes a stop face (64) that comprises the nozzle nose (30) and against which a shoulder (66) of the stabilizer (34) abuts.

11. The molding unit according to claim 2, wherein the actuating device (32) associated with said nozzle nose (30) includes a linear motor.

12. The molding unit according to claim 2, wherein said at least one guide device (46) is carried by the nozzle body (28).

13. The molding unit according to claim 2, wherein said at least one guide device (46) includes at least one pair of guide rings (48), axially superposed in one another.

14. The molding unit according to claim 2, wherein the stabilizer (34) is attached in a detachable manner to the tubular intake element (40) by an attachment device (50) constituted by at least one elastically deformable element.

15. The molding unit according to claim 2, wherein the nozzle (14) comprises a return device (42) that returns the stabilizer (34) toward the bottom position that are arranged axially above said at least one guide device (46).

16. The molding unit according to claim 8, wherein the return device (42) includes a compression spring whose lower end axially rests on a radial support surface (56) that comprises an annular collar (58) that is integral with the tubular intake element (40).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other characteristics and advantages of this invention will emerge from reading the following detailed description for the understanding of which reference will be made to the drawings in which:

(2) FIG. 1 is an axial cutaway view of a molding unit for a machine for manufacturing HR-type containers that shows a mold in the closed position comprising a preform and an associated nozzle in the lowered blow-molding position and that illustrates a stabilizer according to the state of the art in the top position;

(3) FIG. 2 is a cutaway view that shows an example of a preform made of plastic material designed to be transformed into a container;

(4) FIG. 3 is a perspective view that shows a molding unit for the manufacturing of HR-type containers according to an embodiment of the invention and that respectively illustrates a nozzle of said unit comprising actuating means formed by a linear electric motor and a mold that occupies its open position;

(5) FIG. 4 is a view of a molding unit according to FIG. 3 that shows in axial cutaway the nozzle in the raised position and that illustrates a stabilizer that is made in accordance with the teachings of the invention and returned elastically into the bottom position by a spring acting on the tubular element;

(6) FIG. 5 is an axial cutaway view of a molding unit according to FIG. 3 that shows, during the descent toward its lowered position, an intermediate position of the nozzle nose in which the stabilizer works with the neck of a preform in place in the mold in the closed position;

(7) FIG. 6 is an axial cutaway view of a molding unit according to FIG. 3 that shows the nozzle in the lowered blow-molding position and the mold in the closed position and that illustrates a preform kept in position by the stabilizer in the top position and whose neck is covered by the nozzle nose.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(8) In the description below, the axial orientations along a main axis X of the molding unit and the radial orientations at right angles to said axis will be adopted in a nonlimiting manner and to facilitate the understanding thereof.

(9) In a nonlimiting manner, the terms top or bottom as well as upper or lower with reference to the axial orientation, and outside or inside with reference to the radial orientation and in relation to the axis X will be used.

(10) FIGS. 3 to 6 show a molding unit 10 according to an embodiment of the invention provided in a nonlimiting manner.

(11) The molding unit 10 for the manufacturing of HR-type containers is able to equip a manufacturing machine, in particular of rotary design, whose unit 10 then constitutes one of the units (or stations) that are distributed circumferentially in a uniform manner around the axis of rotation of the machine.

(12) Below, the molding unit 10 according to said embodiment of the invention will be described by comparison with that of the state of the art described above and shown in FIG. 1, with the same reference numbers referring to the same means.

(13) The molding unit 10 is designed for the manufacturing of HR-type containers, with the containers being obtained by blow molding or by stretch blow molding from preforms 100 made of plastic material such as the preform shown in FIG. 2.

(14) The preform 100 comprises a neck 104 equipped with a rim 106 that circumferentially delimits an opening 102 for access inside the preform.

(15) As shown in FIGS. 3 to 6, the molding unit 10 comprises at least one HR-type mold 12 associated with a nozzle 14.

(16) The mold 12 comprises at least two half-molds 16 that are mounted to move between at least one open position illustrated in FIG. 3 and a closed position illustrated in FIGS. 5 and 6.

(17) The mold 12 is of the portfolio type, and the half-molds 16 are mounted to move in rotation around an axis O of rotation (see FIG. 3).

(18) In the closed position, the joined half-molds 16 delimit an upper surface 18 that comprises an orifice 20 emptying into a molding cavity 22 that is delimited at least by a molding impression 24 of each half-mold 16.

(19) The half-molds 16 are then adjacent along a parting line P that extends axially.

(20) Preferably, the orifice 20 comprises a peripheral counterbore made in the surface 18 and designed to accommodate the collar 108 of the preform 100.

(21) In the case of a manufacturing of the HR-type container, each molding impression 24 is able to be heated by associated heating means 26 that said mold 12 comprises.

(22) The nozzle 14 of the molding unit 10 partially shown in FIGS. 4 to 6 comprises at least one nozzle body 28 and a nozzle nose 30.

(23) The nozzle nose 30 is mounted to move axially in relation to said nozzle body 28 between a raised position above the mold illustrated in FIG. 4 and a lowered blow-molding position illustrated in FIG. 6.

(24) In FIG. 4, the mold 12 is shown by convenience in the closed position. However, when the nozzle 14 occupies said raised position, the mold 12 is then generally in the open position. The mold 12 of the molding unit 10 occupies its open position when, for example, it is on standby for the insertion of a preform or for releasing a manufactured container that is extracted by transfer means (not shown), such as a clamp.

(25) In the lowered blow-molding position, the nozzle nose 30 rests against the upper surface 18 of the occupying mold 12 in the closed position.

(26) The nozzle nose 30 then establishes an airtight connection so as to inject at least one pressurized fluid, generally air, inside the preform 100 through said opening 102 of the neck 104 of the preform 100.

(27) Preferably, the nozzle nose 30 comprises at its lower axis end sealing means 44 designed to work with the surface 18 to ensure said airtight connection. For some applications, the sealing means 44 such as a seal can be in contact with the collar 108 of the preform 100.

(28) The nozzle nose 30 is controlled axially in movement between said raised and lowered positions by the actuating means 32 that the nozzle 14 comprises.

(29) Preferably, the actuating means 32 associated with said nozzle nose 30 consist of a linear motor shown in FIG. 3.

(30) Advantageously, the linear motor 32 is electric.

(31) The nozzle 14 advantageously comprises a stabilizer 34 that primarily comprises a support surface 36 designed to work with the rim 106 of the neck 104 and blocking means 38.

(32) The blocking means 38 are designed to be inserted inside the neck 104 to immobilize in position the manufactured container, in particular during the opening of the mold 12 for the purpose of initiating the extraction of said container outside of the mold 12.

(33) The stabilizer 34 is housed inside the nozzle nose 30 and forms a movable apparatus with a tubular element 40.

(34) The so-called tubular intake element 40 is hollow in the center to make possible, during the blow molding, the passage of at least one pressurized fluid from a pressurized fluid source supplying the molding unit 10 to the preform 100 to be transformed into a container.

(35) The tubular element 40 is able to be passed through centrally by a stretching rod when the nozzle 14 of the molding unit 10 comprises such a rod for carrying out the manufacturing of the container by stretch blow molding.

(36) The stabilizer 34 is driven axially with said nozzle nose 30 when said nose 30 is moved by the actuating means that are advantageously formed by the linear motor 32.

(37) The stabilizer 34 is able to slide axially relative to said nozzle nose 30 between at least a top position illustrated in FIGS. 5 and 6 and a bottom position illustrated in FIG. 4.

(38) The bottom position corresponds to a position toward which said movable apparatus, and most particularly the stabilizer 34, is returned elastically by return means 42.

(39) Preferably, the return means 42 are formed by at least one spring, such as a compression spring, which stresses axially downward said movable apparatus formed from the stabilizer 34 and the tubular intake element 40.

(40) As shown in FIG. 4, the stabilizer 34 in the bottom position extends in part projecting in relation to the nozzle nose 30, with the blocking means 38 extending in particular axially toward the bottom beyond the sealing means 44 carried by the nozzle nose 30.

(41) As shown in FIGS. 5 and 6, the stabilizer 34 occupies said top position in the presence of a preform 100, when the stabilizer 34 works with the neck 104 of the preform 100 that brings about the axial movement upward of the stabilizer 34 relative to the nozzle nose 30, against the return force exerted by the spring 42.

(42) By its support surface 36 on the rim 106 of the neck 104 of the preform 100, the stabilizer 34 exerts a stabilization force that is oriented axially downward so as to flatten the collar 108 of the preform 100 against the surface 18 of the mold 12, to keep it axially in position for the purpose of blow molding.

(43) The tubular intake element 40 is guided by axial sliding in relation to the nozzle body 28 by at least one guide means 46 that is inserted radially between said nozzle body 28 and said tubular element 40.

(44) The stabilizer 34 is attached to said tubular intake element 40 in such a way that, when thus coupled together, a movable apparatus is created.

(45) Advantageously, the stabilizer 34 is guided in relation to the nozzle body 28 only by said at least one guide means 46.

(46) Preferably, said at least one guide means 46 is carried by the nozzle body 28. As a variant, said at least one guide means 46 is carried by the tubular intake element 40.

(47) Advantageously, said at least one guide means 46 carried by the nozzle body 28 is arranged axially above the stabilizer 34 in such a way as to protect said at least one guide means 46 by removing said at least one guide means 46 from the lower end of the nozzle nose 30 where the thermal stresses are the most significant.

(48) In the embodiment, said at least one guide means 46 advantageously consists of at least one pair of guide rings 48, axially superposed in one another.

(49) Circumferentially with the nozzle nose 30, the stabilizer 34 has a specific radial play that is in particular suitable for allowing thermal expansion under the action of the heat transmitted by the HR-type mold 12, so as to guarantee to the stabilizer 34 a freedom of axial sliding between said top and bottom positions, without the risk of jamming.

(50) By comparison with FIG. 1 illustrating the state of the art, the stabilizer 34 is free to slide in relation to the nozzle body 28 as in relation to the nozzle nose 30.

(51) The axial guiding of the stabilizer previously implemented by cooperation between the outer cylindrical surface 43 of an upper segment of the stabilizer with the inner cylindrical surface 47 for guiding the jacket 45 therefore no longer exists, with the jacket 45 consequently being advantageously eliminated.

(52) Owing to the fact that the stabilizer 34 is guided only by said at least one guide means 46 carried by the nozzle body 28 and working with the tubular element 40 to which said stabilizer is attached, the stabilizer 34 can advantageously be made of plastic material.

(53) By comparison with a metal stabilizer according to the state of the art, the use of plastic material for the stabilizer 34 offers numerous advantages.

(54) The use of plastic material for the stabilizer makes possible a gain in weight in relation to an identical stabilizer that would be made of metal, as was systematically the case heretofore in the state of the art for an application to the manufacturing of HR-type containers.

(55) Advantageously, the dimensions of the stabilizer 34 can be optimized for reducing the dead volumes inside the nozzle nose 30, with the weight reduction obtained for the benefit of the changing for the plastic material making it possible where, by comparison, this would have been impossible when operating with metal.

(56) Thanks to the weight reduction obtained by the use of plastic material for producing the stabilizer 34, the rates are advantageously increased.

(57) The reduction of the on-board weight makes it possible to increase the speed of motion of the nozzle nose 30 between the raised and lowered positions.

(58) The use of a linear motor 32 for driving the nozzle nose 30 is also part of obtaining higher rates, in particular because of the accelerations suitable for such a motor.

(59) Advantageously, the linear motor 32 makes it possible to carry out deceleration at the end of travel that reduces the kinetic energy dissipated during the docking between the stabilizer 34 made of plastic material and the neck 104 of the preform 100.

(60) Advantageously, and by comparison with a metal material, the use of a stabilizer 34 made of plastic material makes it possible to limit the deterioration that can occur in the neck 104 of the preform 100.

(61) Preferably, the stabilizer 34 is attached in a detachable manner to the tubular intake element 40 by the attachment means 50 constituted by at least one elastically deformable element.

(62) Advantageously, said at least one elastically deformable element that forms the means 50 for attachment of the stabilizer 34 with the tubular intake element 40 is an annular retaining ring.

(63) Preferably, the annular retaining ring 50 is carried by the stabilizer 34 and is accommodated in an annular groove 52 complementary to the tubular element 40.

(64) Advantageously, the nozzle 14 comprises means 42 for returning the stabilizer 34 toward the bottom position that are arranged axially above said at least one guide means 46.

(65) Thanks to such an arrangement and by comparison with the state of the art, the return means 42 of the stabilizer 34 are advantageously best protected from the thermal stresses that have existed heretofore, in particular because of the transfer of heat that takes place between the mold 12 and the nozzle nose 30 during the manufacturing of the HR-type containers.

(66) Preferably, the return means 42 consist of a compression spring whose upper end axially rests on a radial support surface 54 of the nozzle body 28.

(67) Preferably, the lower end of the compression spring 42 constituting the return means axially rests on a radial support surface 56.

(68) Advantageously, said radial support surface 56 of the spring 42 belongs to an annular collar 58 that is integral with the tubular intake element 40.

(69) The return means 42 axially stress the stabilizer 34 toward the bottom position, without, however, being directly in contact with the stabilizer 34, which is advantageous when said stabilizer 34 is made of plastic material.

(70) Preferably, a support ring 60 is inserted axially between the upper end of said spring 42 and said radial support surface 54 of the nozzle body 28 and/or between the lower end of the spring 42 and said radial support surface 56 carried by the annular collar 58 of the tubular element 40.

(71) The nozzle 14 comprises stop means axially determining at least one of said bottom and top positions of the movable apparatus formed by the stabilizer 34 and the tubular element 40.

(72) Advantageously, the nozzle 14 comprises stop means 62 that, determining the bottom position, consist of a stop surface 64 that comprises the nozzle nose 30 and against which a shoulder 66 of the stabilizer 34 abuts.

(73) Preferably, an elastically deformable element 68 is inserted axially between said shoulder 66 of the stabilizer and the stop surface 64 carried by the nozzle nose 30.

(74) The operation of the molding unit 10 is illustrated by FIGS. 4 to 6.

(75) In FIG. 4, the nozzle 14 is in the raised position, and the mold 12 is, in the absence of a preform 100, in the open position. A preform 100 is then brought by transfer means (not shown), such as a clamp, and inserted into the mold 12 whose half-molds 16 are moved toward the closed position.

(76) Simultaneously, the actuating means 32 are controlled to cause the descent of the nozzle nose 30 that leaves the raised position to be directed toward the lowered position.

(77) During the descent, the projecting stabilizer 34 then enters into contact with the neck 104 of the preform 100; the blocking means 38 penetrate through the opening 102 inside the neck 104 of the preform 100.

(78) As illustrated by FIG. 5, the stabilizer 34 then works via its support surface 36 with the rim 106 of the preform 100. With the preform 100 resting by its collar 108 against the surface 18 of the mold surrounding the orifice 20, the stabilizer 34 is axially blocked in such a way that the continuation of the descent of the nozzle nose 30 is accompanied by a sliding of the stabilizer 34 relative to the nozzle nose 30.

(79) The descent of the nozzle nose 30 is accomplished when it has reached the lowered blow-molding position shown in FIG. 6, with the seal 44 resting against the surface 18 of the mold 12.

(80) The stabilizer 34 then occupies its top position in which the stabilizer 34, stressed axially downward by the spring 42 acting on the collar 58 of the tubular element 40, applies on the neck 104 of the preform 100 a force that is suitable for keeping it in a specific axial position for the purpose of its transformation into a container.