WO2006064103A1

WO2006064103A1 - Linear type moulding unit for a container manufacturing installation

Info

Publication number: WO2006064103A1
Application number: PCT/FR2005/003027
Authority: WO
Inventors: Philippe Freire-Diaz; Sylvain Auvray
Original assignee: Sidel
Priority date: 2004-12-15
Filing date: 2005-12-05
Publication date: 2006-06-22
Also published as: FR2879179A1; FR2879179B1

Abstract

The invention concerns a unit (6) for moulding containers (2) comprising: a pair of half-moulds (9) mounted respectively on two supports (10) mobile in horizontal translation; a primary transmission (19) controlling the movement of the supports (10); a mould base (14) mounted on a support (15) mobile in vertical translation; a secondary transmission (20) controlling the movement of the mould base support (15); a locking device (16), comprising two mobile bolts (17) each co-operating with a half-mould support (10); a tertiary transmission controlling the movement of the bolts (17). The transmissions include cams mounted on a common shaft, coupled respectively to the half-mould supports, to the mould base support and to the bolts.

Description

Linear type molding unit for a container manufacturing plant

The invention relates to the manufacture of containers. It relates more particularly to a molding unit for an installation for blowing or stretch-blow molding containers. In such an installation, blanks (generally made of a thermoplastic material such as PET) are first heated in a furnace at a temperature below (but close to) their glass transition temperature and then transferred. to a molding unit where they are shaped by blow molding or stretch-blow molding. There are currently two major families of molding units. In the first, . which corresponds to high production rates (greater than 10,000 containers / hour), are grouped rotary machines, in which a carousel carries a plurality of molds distributed on its circumference, each mold comprising two half-molds rotatably mounted; one relative to the other along an axis parallel to the axis of the container, where _. the containers are successivemerit molded to the unit. To illustrate this technique, reference may be made to the patent application published under the number FR 2 793 722, in the name of the applicant.

In the second, which corresponds to more modest production rates (less than 10,000 containers / h), are grouped so-called linear machines, in which a mold comprises two half-molds movable in translation relative to each other , perpendicular to the joint plane of the mold. In this family, the rates can be increased by providing a multi-cavity mold for the simultaneous molding of several containers. The invention relates to this second family of molding units. It should be noted that between the furnace and the molding unit is generally interposed a transfer device to collect by batch the blanks at the furnace outlet and introduce them into the molding unit by adjusting their spacing. Neither the heating nor the transfer of the blanks being concerned with the present invention, we will not address these issues in more detail in the following. A first difficulty faced by manufacturers in the linear technique concerns the opening and closing of the half-molds. Indeed, these half-molds (especially when they include several fingerprints) are relatively heavy; however, the opening and closing of the half-molds must be performed in a fraction of a second (of the order of 0.5 seconds). The opening / closing mechanism must therefore be sufficiently powerful, and the minimum friction.

A second difficulty concerns the locking of the half-molds in the closed position (position in which the blowing of the containers takes place). Indeed, during blowing the half-molds undergo significant spreading forces, due to the blowing pressure which can reach 40 bar. Among the known technical solutions, let us quote as an example, the French patent application published under the number FR 2 790 702, also in the name of the applicant. In addition to this application, several patents have been filed by other companies for linear technology. For example, the European patent applications published under the numbers EP 0 703 058 (AK TECHNICAL LABORATORY) and EP 1 533 103 (KOSME). In these documents, the displacement of the moving parts of the molding unit (in particular the half-molds) is ensured by jacks. This technique requires a lot of power hydraulic, considering the masses to move. An alternative technique is to replace the jacks by linear motors or by screw systems (see e.g. patent SIDEL supra, N ^0. FR 2790702). This technique can implement the large torque provided by the electric motors without using the aforementioned hydraulic powers, however the slowness of the helical screw system limits the production rates. Known techniques ultimately prove insufficient to overcome. satisfactorily the difficulties that have just been exposed, and to increase the rates safely.

The invention aims in particular to overcome certain shortcomings, mentioned above, known techniques.

For this purpose, the invention proposes a molding unit for an apparatus for blowing or stretching containers from thermoplastic blanks, which comprises: a pair of half-molds, each provided with at least one a half-molding cavity, respectively mounted on two movable supports. in horizontal translation in a transverse direction perpendicular to a longitudinal direction for feeding the blanks, between a closed position in which the supports are brought together and where the half-cavities jointly form a side wall of the molding cavity, and an open position in which the supports are spaced apart from one of. the other ; a primary transmission controlling the displacement of the half-mold supports and comprising a primary cam mounted on a rotating shaft driven by a motor, and a primary cam follower cooperating with the primary cam and coupled to each half-mold support ; a mold base mounted on a support movable in vertical translation in a direction perpendicular to the longitudinal and transverse directions, between a high position in which an upper surface of the mold base completes the molding cavity in the closed position of the supports, and a position low separated from the high position, under this one;

- a secondary transmission controlling the displacement of the mold base support and comprising a secondary cam mounted on the same rotating shaft, and a secondary cam follower cooperating with the secondary cam and coupled to the support of the mold base; a locking device, which comprises two latches each cooperating with a half-mold support, movable in translation between a locking position in which the locks block the half-mold supports in the closed position, and a release position in which the latches allow the passage of the half-mold supports in the open position;

- A tertiary transmission controlling the displacement of the locks and comprising a tertiary cam mounted on the same rotating shaft, and a tertiary cam follower cooperating with the tertiary cam and coupled to each latch.

In this way, the mechanism for controlling the movements of the parts of the molding unit, of the "all mechanical" type, increases both the reliability and the longevity of the latter. In addition, it is not necessary to resort to fine synchronization settings between the different transmissions, this synchronization arising from the mounting of the cams on a single transmission shaft. Other objects and advantages of the invention will be apparent from the description given below with reference to the accompanying drawings in which Figure 1 is a schematic view showing ^• (part of) an ^{installation,} manufacturing containers from blanks; Figure 2 is a perspective view partially showing a molding unit according to the invention, for a container manufacturing plant; in this figure, the molding unit is shown in a closed / locked configuration; Fig. 3 is a side elevational view showing the molding unit of Fig. 2 along the direction III; - Figures 4A and 4B are views similar to Figure 2, respectively in a closed / unlocked position configuration, and open / unlocked; Figs. 5A, 5B and 5C are front elevation views (with the mold in section) showing the molding unit of Figs. 2, 4A and 4B, in the same positions as in these figures, respectively; Figs. 6A, 6B and 6C are front elevational views showing the molding unit limited to the secondary transmission, in the same positions as in Figs. 5A, 5B and 5C, respectively; and Figs. 7A, 7B and 7C are sectional elevational views showing the molding unit limited to tertiary transmission, in the same positions as in Figs. 5A, 5B and 5C, respectively. In Figure 1 is shown schematically - and partially - a facility 1 for molding containers 2 from blanks 3 (which are in this case preforms) of thermoplastic material, such as PET (polyethylene terephthalate). This installation 1 comprises a carousel 4 on which are mounted the preforms 3, suspended on turners 5 which rotate them at least when they reach a furnace (or heating unit) where they are heated to the parade being for example exposed to the radiation of tubular fluorescent lamps (not shown) ^'

As shown in FIG. 1, the machine 1 also comprises a molding unit 6 equipped with a mold 7 with several cavities or cavities 8 (in this case four), in which the hot blanks 3 are discharged after having been transferred from the heating station by means of a suitable transfer device (not shown).

By convention, it is termed longitudinal and L denotes the direction in which the preforms 3 are fed to the molding unit 6.

The mold 7 comprises two half-molds 9 each provided with at least one half-molding cavity (in this case four) and mounted respectively on two supports 10 movable in horizontal translation on a fixed frame 11 of the molding unit. 6, in a transverse direction T perpendicular to the longitudinal L direction for feeding the preforms 3, between:

a closed position in which the supports 10 are brought together, the half-molds 9 being in mutual contact and the half-cavities jointly forming a side wall of the molding cavity 8 (see FIGS. 5A and 5B), and

an open position in which the supports 10 (and thus the half-molds 9) are spaced apart from one another to allow the evacuation of the container 2 formed (cf. FIG. 5C), then the introduction of the minus a preform 3 between the half-molds 9. More precisely, each half-mold 9 is presented under the form of a monobloc insert part, attached to a plate 12 of the corresponding support 10, oriented in a vertical plane parallel to the longitudinal direction L.

As can be seen in FIGS. 2, 4A and 4B, each support 10 is provided with a pair of superimposed corrugated skids 13, which extend in cantilever transverse projection on the plate 12 opposite the half-mold 9 corresponding.

The mold 7 also comprises a mold bottom 14 which has an upper surface complementary to the bottom of the container 2 to be formed, and mounted on a support 15 movable in vertical translation in a direction perpendicular to the longitudinal and transverse directions, between: - a high position wherein the upper surface of the mold bottom 14 completes the closed mold cavity 8 of the supports 10 (see Figures 5A and 5B), and

- A low position spaced from the upper position, located below it, to allow the evacuation of the container 2 formed (see Figure 5C).

The molding unit 6 further comprises a device 16 for locking the mold 7 in the closed position, in order to allow it to withstand the blowing pressures without inadvertent spacing of the half-molds 9.

The locking device 16 comprises two locks 17 _. , each cooperating with a half-mold support and movable between: a locking position in which the latches 17 block the half-mold supports 10 in the closed position (see FIGS. 2 and 5A), and

A release position, in which the latches 17 allow the passage of the supports of 10 half-molds in open position;

As illustrated in FIGS. 5A to 5C, the locks 11 are movable in vertical translation

(parallel to the movement of the mold base support), the release position being located above the locking position. Each latch 17 is provided d ⁷ a pair of guides 18 transverse bunk fluted, the spacing of which is identical to that of the pads 13 of the support 10 corresponding. In the locked position, the pads 13 abut against one end of the corresponding guides 18, their respective grooves being offset vertically, which prevents any movement of spacing of the supports 10. In contrast, in the release position, the grooves of the pads 13 are in alignment with the grooves of the corresponding guides 18, so that the supports 10 can freely slide apart from one another, the pads 13 sliding in their respective guides 18. The sequence of the movements of the half-mold supports, the mold base support 15 and the locks 17 is as follows.

Starting from a closed / locked configuration of the molding unit 6, in which the half-mold supports 10 are in the closed position, the latches 17 in the locking position and the mold bottom support 15 are in position high (Figures 2, 5A, 6A, 7A), once completed the blowing cycle of the container 2, the latches 17 are moved upwards in the release position (Figures 4A, 5B, 6B, 7B). The configuration of the molding unit 6 is said closed / unlocked. In this configuration, the half-mold supports 10 are held in the closed position, and the mold base support 15 in the up position. The container 2 formed is still in the mold cavity 8. 005/003027

Then the half-mold supports 10 are moved apart in the open position, while the mold base support 15 is moved to its lower position. The molding unit 6 is then in a so-called open / unlocked configuration (FIGS. 4B, 5C, 6C, 7C). In this configuration, the formed container 2 is evacuated, for example to a transitional filling or storage unit. view of a subsequent filling.

In order to allow its passage from one configuration to another, the molding unit 6 comprises several transmissions, namely:

a primary transmission 19 for controlling the displacement of the supports 10 of half-molds,

a secondary transmission 20 for. controlling the ^{'displacement} of the support 15 of the mold bottom, and

- A tertiary transmission 21 to control the movement of the latches 17.

These transmissions, mechanical, are all controlled simultaneously by a common transmission shaft 22, also called camshaft, whose rotation is provided by. a motor 23 controlled by a control unit 24 of the installation, unit 24 which also provides in particular the synchronization of the molding unit 6 and the preform transfer device 3. The primary transmission 19 comprises a. primary cam, mounted on the camshaft 22,. and a follower 26 of primary cam cooperating with the primary cam 25 and coupled to each support 10 half-mold.

More precisely, according to a first embodiment (not shown), the primary cam. and the primary cam follower are common for the two half-mold supports, a lever game alternately ensuring the spacing and approximation of the supports. However, according to a preferred embodiment, corresponding to the drawings, a pair of primary cams 25, and a pair of corresponding primary cam followers 26, are provided to control separately (although in a synchronized manner) the spacing and, reciprocally, the approximation of the supports 10. In fact, such an arrangement is preferable for overcoming - and this with a high operating speed - the inertia of the supports 10 of half-molds (with their corresponding half-molds 9). The two primary cams 25 are mounted at two opposite ends of the camshaft 22, each cam 25 being in the form of a disc in which is formed a groove 27 of asymmetrical profile forming a closed contour cam path around of the axis of rotation of the shaft 22, while the corresponding primary cam follower 26 comprises a roller 28 mounted freely pivoting at the end of a lever 29 rigidly fixed by its opposite end on a secondary shaft offset by relative to the camshaft 22 a distance greater than the radius, the primary cam 25. Two rods 31, also rigidly attached to each end of the secondary shaft 30, are connected to the support 10 of half-mold corresponding to transform the rotational movement of the secondary shaft. 30, due to the rocking movement of the lever 29 during the rotation of the cam 25, in linear motion of the half-mold support 10.

As indicated above, each half-mold support 10 is translationally driven by its own cam follower / cam follower. From this point of view, the molding unit 6 has plane symmetry with respect to a transverse vertical plane, the two primary cam follower / primary cam follower assemblies being head-to-tail mounted, two secondary shafts being provided as this is visible in Figure 2 and Figures 4A to 6B. The secondary transmission 20 comprises a cam 32 secondary, also mounted on the camshaft 22, and a follower 33 of secondary cam cooperating with the secondary cam 32 and coupled to the support 15 of the bottom of the mold.

More precisely, and as can be seen in FIGS. 7A to 7C, the secondary cam 32 has a cam path 34 constituted by its periphery whose contour is asymmetrical, the follower 33 of secondary cam comprising a roller 35 mounted freely pivoting on a lever 35 mounted for free rotation on one of the secondary shafts (for example by means of a sliding contact bearing or bearing), lever 36 on which the mold base support 15 is hingedly mounted by the The weight of the mold base support 15 and its connecting rod 37 may be sufficient to maintain contact of the roller 35 on its cam path 33, but a return spring (not shown) may be provided for continuously urging the lever 36 towards the cam 32.

As for the tertiary transmission 21, it comprises, on the one hand, a tertiary cam 38 mounted on the camshaft 22, leaning against one of the primary cams 25, and like the latter formed by a disc in which is formed a groove 39 (visible in transparency in Figures 7A to 7C) asymmetrical profile forming a closed contour cam path about the axis of rotation of the camshaft 22, and on the other hand, a follower 40 of tertiary cam cooperating with the cam 38 and coupled together with the two locks 17.

The weight of the locks is in practice sufficiently low that a cam follower 40 can alone (via a set of rods) simultaneously control the two locks.

Thus, as shown in FIGS. 7A, 7B and 7C where the tertiary transmission 21 is visible by transparency, the tertiary cam follower 40 comprises a roller 41, which cooperates with the cam path 39, mounted freely pivoting at one end of a lever 42 bent itself mounted to rotate freely on one of the secondary shafts 30. A crank 43, also mounted on this secondary shaft 30 and rigidly attached to the elbow lever 42, is furthermore connected to one of the latches 17 by means of a connecting rod 44 to transform the rotational movement of the lever 42 bent into a translation movement of the latch 17. Another lever 45, substantially symmetrical, is also mounted for free rotation by its center on the other secondary shaft 30. This lever 45 is, by a first end, connected to the elbow of the lever 42 by means of a rod 46 and, at one end opposite to the other latch 17 via a connecting rod 44, to transform the rotational movement of the lever, bent in a vertical translational movement of the latch 17.

As regards the profiles of the cams 25, 32, 38, those skilled in the art are able to produce them according to the dimensions of the molding unit 6 and the cycle retained for the molding operations. Note that in this case, each cam path 27, 33, 39 presents:

A first portion P1 with a large constant radius, which extends substantially over 180 °, which corresponds to: - for the primary cam 25, to the closed position of the corresponding half-mold support 10 (FIGS. 5A, 5B),

for the secondary cam 32, at the high position of the mold base support, for the tertiary cam 38, at the unlocked position of the latches 17 (FIGS. 6A, 6B),

a second portion P2 with a small constant radius radius, which extends substantially over 90 °, and which corresponds to:

- for the primary cam 25, in the open position of the corresponding half-mold support 10 (FIGS. 5A, 5B), - for the secondary cam 32, to the lower position of the mold base support 15, - for the tertiary cam 38, to the locked position of the locks 17 (FIGS. 6A, 6B), and two connecting portions P3 which make a continuous connection between the first portion P1 and the second P2. It follows from the design of the molding unit 6 which has just been described a certain number of advantages.

First, the transmission of the type motion

"All mechanics" makes it possible to overcome the maintenance and safety problems encountered in cylinder hydraulic systems (in particular leakage defects, which are difficult to repair and have safety consequences in view of high pressure oil) . Maintenance of the unit

6 of molding is facilitated by the accessibility of transmissions 19, 20, 21, grouped around a same shaft 22 disposed under the mold 7. The cams 25, 32, 38, as well as the levers and rods 29, 31 , 36, 37, 42, 43, 44,

45, 46, can be easily removed and replaced

(even repaired) in situ. With regard to the drive, a single electric motor 23 is sufficient for the operation of the molding unit 6, this motor 23 driving the camshaft 22 with distribution on the supports 10 of half-molds, support 15 of the bottom of mold and latches 17 without the need to use auxiliary motors, for the sake of simplicity of operation (no synchronization of motors or jacks is necessary) and maintenance. This single motor 23, dimensioned for the parts, to move the heaviest (in this case the supports 10 of half-molds and their half-molds 9 respective), is necessarily suitable for the least heavy parts (the mold base support 15 and the latches 17), so that only one dimensioning is necessary, to the benefit of simplicity of design.

Nomenclature

SIDEL "SMART II"

1 installation

2 containers

3 blanks / preforms

4 carousel

5 spinners

6 molding unit

7 mold

8 cavity

9 half-molds

10 half mold support

11 chassis

12 platinum

13 skate

14 mold bottom

15 mold bottom support

16 locking device

17 locks

18 guides

19 primary transmission

20 secondary transmission

21 tertiary transmission

22 camshaft

23 engine

24 control unit

25 primary cam

26 primary cam follower

27 groove

28 roller

29 lever

30 secondary shaft

31 connecting rods

32 secondary cam

33 cam path

34 secondary cam follower

35 roller

36 lever

37 link

38 tertiary cam

39 groove

40 tertiary cam follower

41 roller

42 elbow lever

43 crank

44 connecting rod

45 symmetric lever

46 connecting rod

P1 first cam portion P2 second cam portion P3 connecting portions

Claims

A molding unit (6) for an installation (1) for blowing or stretching containers (2) from thermoplastic blanks (3), which comprises:

- A pair of half-molds (9), each provided with at least one half-mold cavity, respectively mounted on two supports (10) movable in horizontal translation in a transverse direction perpendicular to a longitudinal direction of feed blanks (3), between a closed position in which the supports (10) are brought together and the half-cavities together form a side wall of a molding cavity (8), and an open position in which the supports (10) are separated from each other;

a primary transmission (19) controlling the displacement of the supports (10) of half-molds;

a mold base (14) mounted on a support (15) movable in vertical translation in a direction perpendicular to the longitudinal and transverse directions, between a high position in which an upper surface of the mold base (14) completes the molding cavity; (8) in the closed position of the supports (10), and a low position spaced from the high position, beneath it;

- a transmission (20) secondary controlling the displacement of the support (15) of the bottom of the mold;

- A locking device (16), which comprises two latches (17) each cooperating with a half-mold support (10) movable in translation between a locking position in which the latches (17) block the supports (10). half-molds in position 27

17 closed, and a release position in which the locks (17) allow the passage of the supports (10) of half-molds in the open position;

a tertiary transmission (21) controlling the displacement of the locks (17); characterized in that

the primary transmission (19) comprises a primary cam (25) mounted on a rotating shaft (22) driven by a motor (23), and a follower (26) of primary cam cooperating with the primary cam (25) and coupled to each half-mold support (10),

the secondary transmission (20) comprises a secondary cam (32) mounted on the same rotating shaft (22) and a secondary cam follower (34) cooperating with the secondary cam (32) and coupled to the support (15). mold bottom;

- The tertiary transmission (21) comprises a cam (38) tertiary mounted on the same shaft (22) rotating, and a follower (40) of tertiary cam cooperating with the tertiary cam (38) and coupled to each latch (17). ).

2. Unit (6) molding according to claim 1, characterized in that the primary cam (25) is in the form of a disc mounted on the shaft (22) rotating and in which is formed a cam path (27), in that the follower (26) of primary cam comprises a roller (28) which cooperates with the corresponding cam path (27), and in that the roller (28) is mounted on a lever

(29) rotatably mounted on a secondary shaft (30) parallel to the rotating shaft (22), said lever (29) being coupled to at least one half-mold support (10) via at least one a connecting rod (31) rigidly mounted on said secondary shaft (30).

3. Unit (6) molding according to claim 1 or 2, characterized in that the follower (26) primary cam is common for the two supports (10) of half-molds.

Molding unit (6) according to claim 1 or 2, characterized in that the primary transmission (19) comprises two primary cams (25) mounted on the rotating shaft (22), as well as two followers (26) of primary cams cooperating respectively with the ^'primary cams (25) and respectively coupled to the two supports (10) half-molds.

5. Unit (6) molding according to one of claims 1 to 4, characterized in that the secondary cam (32) has a cam path (33) constituted by its periphery asymmetric contour, in that the follower (34) comprises a roller (35) mounted on a lever (36), freely rotatably mounted on a secondary shaft (30) and connected to the support (15) of the mold bottom via a connecting rod (37).

6. Unit (6) molding according to one of claims 1 to 5, characterized in that the tertiary cam (38) comprises a disk mounted on the transmission shaft and in which is formed a cam path (39) , in that the follower (40) of tertiary cam comprises a roller (41) which cooperates with the corresponding cam path (39),. . . and in that the roller (41) is mounted on a lever

(42) rotatably mounted on a secondary shaft (30) parallel to the rotating shaft, said lever (42) being coupled to the latches (17) via a set of connecting rods and lever (43, 44, 45 , 46). .

7. Unit (6) molding according to one of claims 1 to 5, characterized in that the locks (17) are provided with guides (18) grooved, in that the supports (10) of half-molds are provided of skates (13) grooves of complementary shape of the guides (18) and which, in the locking position, are in abutment against the guides (18), and in release position .cooperate sliding with them.

8. Installation (1) for manufacturing containers (2) by blow molding or stretch blow molding, which comprises a molding unit (6) according to one of claims 1 to 7.