FR2921010A1 - Mold base support i.e. mounting plate, for container manufacturing machine, has distributor movable between coupling and bypass positions, and intermediate fluid circulation zone generating depression in cavity - Google Patents

Abstract

The support (4) i.e. mounting plate, has a coolant outlet communicated with a cavity (12) by a discharge duct, and a distributor (25) equipped with a coolant bypass duct (28). The distributor is movable between coupling and bypass positions. A coolant inlet (21) and the coolant outlet communicate with the cavity by the distributor, in a coupling position. The bypass duct is equipped with an intermediate fluid circulation zone (35). The zone is configured to generate a depression in the cavity during the circulation of the fluid in the bypass duct in the bypass position.

Description

Bypass mold bottom support for a container making machine

The invention relates to the field of the manufacture of containers, in particular by blow molding or stretch blow molding. The blowing of the containers takes place in a mold, provided with a cavity into which is introduced a preform (usually thermoplastic) preheated, this blank being pressurized to give it a desired shape corresponding to that of the cavity. Modern molds are generally in three parts: two half-molds, articulated in a plane perpendicular to a main axis of the mold, either in translation or in rotation around a common hinge (the mold then being said to be of the wallet type), and a mold base movable parallel to the axis of the mold. Molds are generally temperature-controlled, either for cooling in the most common applications, or for heating in HR (Heat Resistant) applications where the containers are thermofixed by temporarily holding them in the heated mold. to make them mechanically resistant to shrinkage during hot filling. Conduits for the circulation of a coolant (usually oil or water) are provided for this purpose in the half-molds, and in the mold bottom.

In an open configuration, the two half-molds are spaced from each other and the mold bottom is in a low position, which allows the evacuation of a formed container and the introduction of a new one. draft. In a closed configuration, the mold bottom is in a high position and the two half-molds are closed on it.

In order to allow the interchangeability of the mold bottom to allow the manufacture of containers of different ranges (and shapes) within the same machine, the mold base is usually fixed in a removable manner on a sliding support provided with a heat transfer fluid inlet duct, and an exhaust duct. A fixing mechanism with fluidic connection makes it possible to ensure the removable attachment of the mold bottom to the saddle, while ensuring the sealed continuity of the circulations of the coolant.

The fluidic connection is in the form of an assembly of moving parts slidable relative to one another. When the mold base is mounted on the support, the fitting adopts an open configuration in which it allows the coolant, under pressure, to circulate in the ducts formed in the mold base. In contrast, when the mold bottom is separated from the support, the fitting adopts a closed configuration in which the pressurized fluid is sealed in the holder. The assembly operations and disassembly of the mold base on its support, during the establishment of the mold (for example during a change of production range), are performed automatically or manually. Now it has been found that a large force (parallel to the axis of the mold) opposes both the coupling and the separation of the mold bottom and the support. Analyzes have shown that this force results from the pressure of the fluid which, acting on the moving parts of the fluidic connection, opposes their movement. Automatic assembly and disassembly operations therefore require powerful and therefore expensive robots. As for manual operations, they are generally above the forces of an average person. The invention aims to solve the aforementioned drawbacks, by proposing a solution to facilitate the assembly and disassembly of the mold base on its support. For this purpose, the invention proposes a mold base support provided with a mechanism for removably attaching said mold bottom with fluid connection, said support being provided with a fluid circuit provided with: a heat transfer fluid inlet in communication , via a supply duct, with a cavity adapted to receive at least in part a fluidic connection, and a heat transfer fluid outlet in communication, via a discharge duct, with said cavity, this support further comprising a distributor provided with a heat transfer fluid bypass duct, this distributor being mounted movably between: a so-called coupling position in which the distributor puts in communication the fluid inlet and the outlet of fluid with the cavity, and a so-called bypass position in which the distributor closes the supply and evacuation conduits and puts in direct communication, by the bypass duct, the arrival of fluid with the fluid outlet, said bypass duct being provided with an intermediate fluid circulation zone, in communication with the cavity and configured to generate a depression therein during the circulation of the fluid in the bypass duct in bypass position. Other objects and advantages of the invention will become apparent in the light of the description given hereinafter with reference to the accompanying drawings in which: FIG. 1 is a perspective view, approximately at scale 1, showing a mold bottom next to his support; FIG. 2 is a side view of the support, approximately at scale 1; FIG. 3 is a side view of the support, turned 90 ° with respect to FIG. 2; Figure 4 is a sectional elevation of the support of Figure 2, along the section plane IV-IV; Figure 5 is a partial sectional view of the support of Figure 4, along the section plane V-V; Figure 6 is a detail view in section, on an enlarged scale, of the support of Figure 4, along the section plane VI-VI; Figure 7 is a detail sectional view of the support of Figure 4, according to the inset VII; Figure 8 is a detailed sectional view of the support of Figure 7, along the section plane VIII-VIII; Figure 9 is a side view of the assembled support and mold base, Figure 10 is a sectional elevational view of the assembly of Figure 9, along the X-X section plane; Figure 11 is a detail view in section, on an enlarged scale, of the support of Figure 10, along the section plane XI-XI. FIG. 1 shows a bottom 1 of a mold which is in the form of a block of metal (made of steel or an aluminum alloy) having, on an upper surface, a cavity recess 2 intended to impart its form at the bottom of a container. Thanks to a mechanism 3 removable attachment, the bottom 1 is mounted rigidly but not permanently on a support 4, hereinafter referred to as fifth wheel, movable in an axial direction coincides with a general axis of symmetry of the bottom 1 and the harness 4. The bottom 1 is provided with a conduit 5 for the circulation of a heat transfer fluid, hollowed out in a spiral (or, alternatively, in concentric ring portions) in a lower face of the bottom 4, opposite to the cavity 2 The bottom 1 is further provided with a housing 6 for receiving a male part of a fluidic connection 7. The bottom 1 further comprises a cylindrical ring 8 provided with an annular bead 9 projecting radially outwardly and defining a male portion of the fastening mechanism 3.

The fifth wheel 4 comprises a cylindrical central body 10 provided at its center, on the side of an upper face 11 of the body 10, with a succession of bores forming a cavity 12 for a female part 13 of the fluidic connection 7. The fifth wheel 4 further comprises a cylindrical cage 14 surrounding the body 10 and provided with a plurality of conical holes 15 in which are housed balls 16 movable radially. Between the cage 14 and the body 10 is defined a cylindrical housing 17, defining the female part of the fixing mechanism, and in which is mounted axially movable an annular slide 18 which, in a decoupled configuration of the fifth wheel 4 (Figure 1) where the bottom 1 is separated from it, is close to the upper face 11 of the body 10 and, in a coupled configuration of the fifth wheel 4 (Figure 10), is pressed into the housing 17 under the pressure of the crown 8 against a return spring.

The fifth wheel 4 further comprises a ring 19 surrounding the cage 14 and completing the fixing mechanism 3. This ring 19 is slidably mounted around the cage 14, between a low position, called unlocking position (FIG. 1), corresponding to the decoupled configuration of the fifth wheel 4, in which the balls 16 are received, under the radial pressure of the slide 18 , in an annular reserve 20 hollowed out in the ring 19, and a high position (FIG. 10), referred to as locking, corresponding to the coupled configuration of the fifth wheel 4, in which the ring 19 radially pushes the balls 16 against the bead 9 of the crown 8, thus ensuring a rigid attachment of the bottom 1 on the fifth wheel 4. The fifth wheel 4 is further provided with a fluid circuit which comprises, for the supply of heat transfer fluid of the conduit 5 formed in the bottom 1: an arrival 21 fluid, in communication with the cavity 12 through a conduit 22 supply, and a fluid outlet 23 in communication with the cavity 12 through a conduit 24 discharge. When the fifth wheel 4 is mounted in a molding unit of a container manufacturing machine, heat transfer fluid supply and discharge hoses are connected to the inlet 21 and the outlet 23, respectively.

The supply duct 22 and the discharge duct 24 are each in the form of a succession of channels pierced in the body 10 of the fifth wheel 4 and opening into the cavity 12. As illustrated in FIG. the fifth wheel 4 further comprises a distributor 25 comprising a tubular hollow body 26 fitted into a through bore 27 formed transversely in the body 10 of the fifth wheel 4. The body 26 of the distributor 25 is pierced with an axial conduit 28 of fluid bypass coolant, the distributor 25 being rotatably mounted in the body 10 of the fifth wheel 4 between: a coupling position (Figures 9 to II) in which the distributor 25 communicates the fluid inlet 21 and the outlet 23 of fluid with the cavity 12, and a bypass position (Figures 1 to 8) in which the distributor 25 closes the supply ducts 22 and the outlet duct 24 and puts in direct communication, through the conduit 28 bypass, the arrival 21 of fluid with the outlet 23 of fluid.

More specifically, as can be seen in FIGS. 5 and 6, the body 26 of the distributor 25 has, at an upstream end 29 situated on the side of the fluid inlet 21, a first bore 30 made perpendicularly to the axis of the distributor. 25 through it and which, in the coupling position, communicates the fluid inlet 21 with the cavity 12 via the supply conduit 22. At this same upstream end 29, the body 26 of the dispenser 25 also has a second bore 31, not through, opening into the bypass duct 28 and made perpendicularly to the axis of the distributor 25 while being offset angularly relative to the first piercing. 30, about 90 ° in the illustrated embodiment. In the bypass position, this second bore 31 places the fluid inlet 21 in communication with the bypass duct 28, the supply duct 22 being closed off by the wall of the body 26 of the distributor 25 facing the second bore 31 (FIG. 5). At a downstream end 32, situated on the side of the fluid outlet 23, the body 26 of the distributor 25 also comprises a first bore 33 made perpendicularly to the axis of the distributor 25 through the latter and which, in position d coupling, communicates the cavity 12 with the outlet 23 of fluid via the conduit 24 for evacuation (Figure II). At the same downstream end 32, the body 26 of the distributor 25 also has a second bore 34, not through, opening into the bypass duct 28 and made perpendicularly to the axis of the distributor 25 while being offset angularly relative to the first hole 33, about 90 ° in the illustrated embodiment. In the bypass position, this second bore 34 puts the bypass conduit 28 into communication with the fluid outlet 23, the outlet pipe 24 being closed off by the wall of the body 26 of the distributor 25 facing the second bore 34 (FIG. ). Thus, in the coupling position of the dispenser 25, the fluid flows from the inlet 21 to the outlet 23, passing through the cavity 12 via the supply conduit 22 and the discharge conduit 24. In the bypass position of the distributor 25, the fluid flows from the inlet 21 directly to the outlet 23 while passing through the conduit 28 bypass. As illustrated in FIG. 4, and in more detail in FIG. 7, the bypass duct 28 has, between the two ends 29 and 32, an intermediate fluid circulation zone 35 in fluid communication with the cavity 12. This zone 35 is configured to generate, in the manner explained hereinafter, a depression during the circulation of the fluid in the bypass position of the distributor 25. More precisely, in the intermediate zone, the bypass conduit 28 has a restriction of section, formed of an upstream frustoconical portion 36, located on the side of the upstream end 29 (that is to say on the side of the fluid inlet 21) and whose section decreases from the end 29 upstream to the downstream end 32, followed (in the fluid flow direction) by a downstream frustoconical portion 37, situated on the downstream end 32 side (that is to say on the outlet side 23). fluid) and whose section is increasing from the upstream end 29 to the downstream end 32. According to an embodiment illustrated in FIG. 7, these frustoconical portions 36, 37 communicate by their vertices via a cylindrical central channel 38.

The bypass duct 28 has, on the one hand, an upstream portion 39 of constant diameter, connecting the bores 30, 31 made at the upstream end 29 and the upstream frustoconical portion 36 and, on the other hand, a downstream portion 40. of constant diameter connecting the downstream frustoconical portion 37 and the holes 33, 34 made at the downstream end 32.

According to an embodiment illustrated in FIGS. 5 and 7, the diameters of these portions 39 and 40 are substantially equal. As can be seen in FIG. 7, the angular opening of the upstream frustoconical portion 36 is greater than the angular opening of the downstream frustoconical portion 37. Since the lengths of these frustoconical portions 36, 37 are substantially equal, a secondary downstream frustoconical portion 41 may be provided, forming a junction between the downstream frustoconical portion 37 and the downstream portion 40 of constant diameter, and whose angular aperture is greater than that of the frustoconical portion 37 downstream.

The body 26 of the dispenser 25 further comprises at least one channel 42 pierced laterally in the wall thereof, and opening, on the one hand, at an outer end 43, on an outer face 44 of the body 26 of the dispenser 25 and on the other hand, at an opposite inner end 45, in the downstream frustoconical portion 37. More specifically, at its outer end 43, the channel 42 opens into a central portion 46 of the outer face 44 of the body 26 of the distributor 25 facing the cavity 12 (in other words, when the heat transfer fluid circulates in the fifth wheel 4 and invades the cavity 12, this portion 46 of the outer face 44 is immersed in the fluid present in the cavity 12. In one embodiment, illustrated in FIG. 7, this portion 46 of the outer face 44 has a diameter smaller than the diameter. overall of the body 26 of the distributor 25 (diameter measured for example at the ends 29, 32 upstream or downstream), so that between the portion 46 of smaller diameter and the bore 27 formed in the body 10 of the fifth wheel 4 is defined an annular chamber 47, which is placed in communication with the cavity 12 by a lateral bore 48. As can be seen in Figure 7, the lateral channel 42 extends obliquely with respect to the main axis of the conduit 28. bypass and opens, at its inner end 45, at the top of the downstream frustoconical portion 37, at the junction with the central channel 38. More specifically, the lateral channel 42 forms with the axis of the bypass duct 28 an acute angle opening towards the upstream end 29. In practice, the distributor 25 preferably has two identical lateral channels 42 arranged symmetrically at 180 ° with respect to the main axis of the bypass conduit 28.

When the distributor 25 is placed in its bypass position, the coolant coming from the inlet 21 circulates through the bypass conduit 28 passing successively through the second bore 31, the upstream portion 39 of constant diameter, the portion 36 upstream frustoconical portion 37, the central channel 38, the downstream frustoconical portion 37, the secondary downstream frustoconical portion 41, the downstream portion 40 of constant diameter, then is evacuated via the second bore 34 through the outlet 23. Given the progressive restriction of the cross section in the upstream frustoconical portion 36, the fluid pressure increases, while its speed increases (constant flow). In the central channel 42, pressure and fluid velocity are constant. On the other hand, as soon as it enters the downstream frustoconical portion 37, the increase in the cross-section decreases the pressure and the velocity of the fluid, which, at the internal end 45 of the lateral channel 42, creates a depression. which generates a suction effect of the fluid present in the chamber 47 (and consequently in the cavity 12). This results in a decrease in the fluid pressure prevailing in the cavity 12, which facilitates the displacement of the constituent parts of the fluidic coupling 7 during the coupling and the separation of the bottom 1 and the fifth wheel 4, the forces mobilized. to perform these operations being significantly reduced.

The rotation of the dispenser 25 can be controlled in various ways. According to an embodiment illustrated in the figures, the dispenser 25 comprises, at at least one end (in practice at each of its ends), a crank 49 provided with a cam follower 50 which cooperates with a cam path 51 arranged in an oblong hole 52 formed in the ring 19. Thus, in the locking position of the ring 19 (FIGS. 9 to 11), the latter forces the distributor 25, via the cam follower cam 51 / follower 50, to adopt its coupling position, the inlet 21 and the outlet 23 then being placed in communication with the cavity 12. In the unlocked position against (FIGS. 2 and 4 in particular), the ring 19 constrains the distributor 25, via the cam torque 51 cam follower 50, to adopt its bypass position, angularly offset by about 90 ° with respect to the coupling position, the inlet 21 and the outlet 23 then being placed in direct communication with the ducts 22, 24 of the cam. closed supply and evacuation. In order to avoid any unwanted rotation of the ring 19, it can, as illustrated in FIG. 3, be provided with a window 53 made parallel to the axis of displacement of the ring 19, and in which is accommodated a pin 54 fixed perpendicularly in the body 10 of the fifth wheel 4. In addition to ensuring the tightness of the closure of the conduits 22, 24 of supply and discharge in the bypass position of the distributor 25, the fifth wheel can comprise two pairs of O-ring seals disposed on either side of the bores 30, 31 and 33, 34 respectively at the ends 29, 32 upstream and downstream of the body 26 of the distributor 25, between the latter and the body 10 of the harness 4.

The following table provides an experimental example of embodiment using water as heat transfer fluid. The parameters are noted as follows: D1 - outer diameter of the body 26 of the distributor 25, D2 - diameter of the portion 46 of smaller diameter, D3-diameter of the upstream portion 39 of constant diameter, D4 - diameter of the portion 40 downstream of constant diameter, D5 - diameter of the central channel 38 D6 - diameter of the lateral channels 42 al - angular opening of the upstream frustoconical portion 36, a2 - angular opening of the frustoconical portion 37 downstream, a3 - angular opening of the frustoconical portion 41 secondary downstream, a4 - angle of the lateral channels 42 with the axis of the duct L1 - length of the upstream frustoconical portion 36, L2 - length of the downstream frustoconical portion 37, L3 - length of the central channel 38, D - flow of fluid in inlet of the distributor 25, in the bypass position, P1-fluid pressure at the inlet of the distributor 25, in the bypass position, P2-pressure (observed) of fluid at the outlet of the distributor 25, in the bypass position. Parameter Preferred range Preferred value Dl 12mm-14mm 13mm D2 9mm - 11mm 10.5mm D3 5mm - 7mm 6mm D4 5mm-7mm 6mm D5 1mm - 2mm 1.7mm D6 0.8mm - 1.3mm 1 mm a1 15 ° - 30 ° 26 ° a2 5 ° - 20 ° 10 ° a3 70 ° - 100 ° 90 ° a4 30 ° - 70 ° 60 ° L1 6mm - 12mm 9mm L2 6mm-12mm 9mm L3 1mm - 4mm 2.5 mm D 4 I / min - 10 I / min 7 I / min P1 3 bar - 5 bar 4 bar P2 2 bar - 3 bar 2.5 bar This example allows to obtain a reduction of the fluid pressure in the cavity 12, sufficient to allow easy manual assembly and disassembly of the bottom 1 and the fifth wheel 4. A fortiori, the automation of these operations can be achieved with a relatively reasonable machine power.

NOMENCLATURE 1 bottom mold 2 footprint 3 fixing mechanism 4 fifth wheel in the bottom 6 housing in the bottom of mold 7 fluidic connection 8 crown 9 annular bead fifth wheel body 11 upper face 12 cavity 13 female part of the fitting 14 cage bead holes 16 balls 17 housing for the slider 18 slider 19 ring annular reserve 21 inlet 22 supply pipe 23 outlet 24 exhaust pipe distributor 26 valve body 27 bore 28 bypass pipe 29 upstream end first bore 31 second bore 32 downstream end 33 first bore 34 second bore intermediate zone 36 upstream frustoconical portion 37 downstream frustoconical portion 38 central channel 39 upstream portion of constant diameter downstream portion of constant diameter 41 secondary frustoconical portion 42 lateral channel 43 external end 44 external face of the distributor inner end 46 portion of lesser diameter 47 cylindrical chamber 48 piercing side 49 crank cam follower 51 cam 52 slot 53 window 54 pin O ring 5

Claims (20)

1. Support (4) for the bottom (1) of a mold provided with a mechanism (3) for detachably fixing said bottom (1) with a fluid connection, said support (4) being provided with a fluid circuit provided with: arrival (21) of heat transfer fluid in communication, via a conduit (22) supply, with a cavity (12) adapted to receive at least partially a fluidic connection (7), and an outlet (23) heat transfer fluid in communication, via a conduit (24) discharge, with said cavity (12), the support (4) being characterized in that it comprises a distributor (25) provided with a conduit (28) for bypassing the coolant, this distributor (25) being mounted movably between: a so-called coupling position in which the distributor (25) puts the fluid inlet (21) in communication with the outlet (23) of fluid with the cavity (12), and a so-called shunt position in which the distributor (25) 20 closes the conduits (22, 24) supply and evacuation and puts in direct communication, through the duct (28) bypass, the inlet (21) of fluid with the outlet (23) of fluid, said duct (28) bypass being provided with a zone ( 35) intermediate fluid circulation, in communication with the cavity (12) and 25 configured to generate a depression therein during the flow of fluid in the conduit (28) bypass in bypass position. 2. Support (4) according to claim 1, characterized in that the conduit (28) bypass has, in the zone (35) intermediate, a section restriction. 3. Support (4) according to claim 2, characterized in that the section restriction comprises an upstream frustoconical portion (36) located on the side of the inlet (21) of fluid, and a portion (37) frustoconical downstream, located on the side of the outlet (23) of fluid, these frustoconical portions communicating by their vertices. 4. Support: (4) according to claim 3, characterized in that the distributor (25) comprises at least one channel (42) opening on the one hand, at one end (43) external, on a portion (46). ) of an outer face (44) of the distributor (25) giving into the cavity (12) and, on the other hand, at an opposite end (45) in the downstream frustoconical portion (37) 5. Support (4) according to claim 4, characterized in that said channel (42) opens at its end end (45) internal to the top of the portion (37) frustoconical downstream. 6. Support (4) according to claim 4 or 5, characterized in that the channel (42) laterally extends obliquely relative to a main axis of the duct (28) bypass. 7. Support (4) according to claim 6, characterized in that the channel (42) is inclined side, relative to the main axis of the duct (28) by an angle of between 30 ° and 70 ° . 8. Support (4) according to one of claims 4 to 7, characterized in that the channel (42) side has a diameter of between 0.8 mm and 1.3 mm. 9. Support (4) according to claim 8, characterized in that the channel (42) side has a diameter of about 1 mm. 10. Support (4) according to one of claims 4 to 9, characterized in that the distributor (25) comprises two channels (42) side disposed symmetrically at 180 °. 11. Support (4) according to one of claims 3 to 10, characterized in that the portions (36, 37) frustoconical upstream and downstream are connected by a channel (38) central cylindrical. 12. Support (4) according to one of claims 3 to 1 1, characterized in that the portion (36) frustoconical upstream has an apex angle between 15 ° and 30 °. 13. Support (4) according to one of claims 3 to 12, characterized in that the portion (37) downstream frustoconical has an apex angle of between 5 ° and 20 °. 14. Support (4) according to one of claims 1 to 13, characterized in that the distributor (25) has, on an outer face (44), a portion (46) of smaller diameter at which the area ( 35) fluid circulation intermediate communicates with the cavity (12). 15. Support (4) according to one of claims 1 to 13, characterized in that the distributor (25) is rotatably mounted in a body (10) of the support (4). 16. Support (4) according to claim 15, characterized in that the distributor (25) comprises a body (26) tubular fitted in a bore (27) made transversely in the body (10) of the support (4). 17. Support (4) according to claim 15 or 16, characterized in that the distributor (25) has: at one end (29) upstream, a first bore (30) clean, in the coupling position, to put in communication the arrival (21) of fluid with the cavity (12), and a second bore (31), angularly offset relative to the first bore (30) and adapted to put in communication the arrival (21) of fluid with the conduit (28) at a downstream end (32), a first bore (33) clean, in the coupling position, to communicate the cavity (12) with the fluid outlet (23), and a second bore (34), angularly offset from the first bore (33) and adapted to put in communication the conduit (28) bypass with the outlet (23) of fluid. 18. Support (4) according to claims 16 and 17, taken together, characterized in that it comprises two pairs of O-ring seals (55) arranged on either side of the bores (30, 31; 34) at the ends (29, 32) upstream and downstream of the distributor (25), between the body (26) thereof and the body (10) of the support (4). 19. Support (4) according to claim 17 or 18, characterized in that the first bore (30; 33) and the second bore (31; 34) are angularly offset by 90 °. 20. Support (4) according to one of claims 15 to 19, characterized in that the distributor (25) comprises, at one end at least, a crank (49) provided with a cam follower (50) cooperating with a cam path (51) formed in a ring (19) of the locking mechanism (3), this ring (19) being movable in translation between: a locking position in which it forces the distributor (25) via the pair cam (50) / follower (51), to adopt its coupling position, and an unlocking position in which it constrains the distributor (25), via the cam (50) / cam follower (51) , to adopt its derivation position. 10