IMPROVEMENT IN AN APPARATUS FOR PRODUCING CONTAINERS OF THERMOPLASTIC MATERIAL

Abstract: Apparatus for blow moulding hollow plastic bodies (7) comprising a plurality of pairs of mutually joinable half-moulds (2, 4) capable of being opened and closed, associated to an appropriate rotary apparatus (10) carrying said half-moulds (2, 4), a retrieval device adapted to remove the finished container (7) from the respective pair of half-moulds (2) after the opening thereof, an opening and closing mechanism adapted to close the half-moulds (2, 4) after the passage thereof through the position of the preform feeding mechanism, and to open them before the passage thereof through the position of the finished-container removal mechanism, in which said pairs of half-moulds (2, 4) are constituted by a fixed half-mould (2) and a moving half-mould (4) that is capable of being opened from and closed against said fixed half-mould (2). In a preferred manner, said fixed half-moulds (2) are linked to said rotary apparatus (10) and are arranged in a substantially vertical position, with the respective moving half-mould (4) adapted to be closed by accomplishing a substantially rotary movement about a horizontal axis of rotation.

Description: IMPROVEMENT IN AN APPARATUS FOR PRODUCING CONTAINERS OF THERMOPLASTIC MATERIAL DESCRIPTION The present invention refers to an improved apparatus for the production of containers made of thermoplastic material, m particular polyethylene terephtalate (PET) and polypropylene (PP), intended for use in applications implying them being filled with liquids at elevated temperatures and/or containing C0 2 (carbon dioxide) gas, provided with devices that enable the productivity of the moulds during the blow moulding phase to be increased In particular, the present invention is particularly advantageous when the described devices are associated to a preform manufacturing apparatus included in a so-called single-stage plant, but can be advantageously used also in conjunction with apparatuses that are supplied with previously manufactured preforms and are solely intended to carry out the final blow moulding phase (le. two-stage plants) In a two-phase process, a previously produced preform or panson, which is in a substantially amorphous state, is heated up again to its preferred molecular onentation temperature, at which it is then blow-moulded into the desired shape. As used in this context, the term "two-stage process", or "double-stage process", shall be understood to cover any process that produces a preform or panson which must then be heated up from ambient temperature to the related blow-mouldmg temperature In contrast therewith, single-stage processes are so defined in that they are capable of forming the so-called preform, or panson, and transferring said preform from the injection mould or extrusion die (upon it having been allowed to cool down to some appropnate temperature) to a conditioning station, where it is allowed to evenly level at a temperature of preferred molecular onentation Said preform or panson is then transferred to a blow-mouldmg mould, in which it is finally moulded into its desired form According to a pnor-art technique, the cavities m which the preforms are injection moulded and the preform transferring and conditioning devices are arranged in an on-line configuration along with the blow-mouldmg moulds so as to ensure an easier more convenient handling of the preforms, the containers and the vanous therewith associated members According to such a construction principle, both preforms and finished containers are processed m successive groups, with the same processing and/or transferring operations occurring at the same time In particular, the blow moulding tools, le the moulds, are particularly cntical m this connection, since with the increasing blow moulding pressure and the increase in the number of cavities contained in each pair of blow moulding platens, more rapid and powerful pumping stations are required Furthermore, the increased total pressure produced by the bottles during blow moulding must be opposed by a corresponding greater mould clamping pressure Such a greater pressure, which can be estimated to amount to a clamping force exerted on the moulds in excess of 100,000 kgf, would require all mechanical and pneumatic organs intended to produce and withstand such a pressure to be sized accordingly, which generally means to a very burdensome extent Such a huge and, what's more, pulsating pressure, however, has a negative effect also on the resistance of the moulds themselves, which are not only so exposed to a greater pressure, but have at the same time be capable of withstanding such a pressure over a much greater extension thereof, owing to the greater number of blow moulding gates, and this of course causes the ngidity thereof to become a critical factor It makes also easier for the moulds to warp outwardly, thereby affecting the bottle blow-moulding results in an easily understandable manner Furthermore, when use is made of blow moulding moulds provided with a large number of cavities, the time needed for all preforms to be transferred into the respective cavities increases in a proportional manner with a corresponding increase in the cycle time and a resulting reduction m the overall productivity of the plant In order to do away with such drawbacks, a largely known solution lies in the replacement of blow moulding moulds provided with a plurality of on-line cavities with a smaller number of individual moulds, le comprising a single respective blow moulding cavity, which are arranged along the penphery of a rotating carousel-like structure, such as this is for instance illustrated in WO 95/05933, WO 89/01400, US 4,850,850 and US 4,313,720 In particular, WO 89/01400 teaches that said blow moulding half-moulds are adapted to open and close in a book-like manner about respective axes of rotation that are orthogonal to the plane on which the preforms and the finished containers move Such a solution, although effective in solving the afore cited problems, does not however go without some drawbacks that are summanzed below a) the need anses for two half-moulds to be handled and dnven and this of course adds to the complexity of the structures and causes costs to nse, b) the lateral rotary movement of both said half-moulds requires of course the availability of adequate lateral space and this of course puts a penalty on the compactness of the plant, c) the handling means provided must be able to introduce the preforms from the front zone of the half-moulds, as well as to again remove the respective finished containers from the same front zone, and this of course understandably adds significantly to the complexity of both construction and operation of the plant However, during operating tests earned out on some types of plants having the characteristics as recited in the appended claims 1 to 5, and made with the use of knownn techniques of more obvious and immediate choice, such as the use of a direct pneumatic control or electromagnetic actuators or means like a lever joint generally known as toggle joint in the art, is has been observed that a number of problems tend to come afloat in connection with the opening and closing, or clamping, of the moving half-mould, le - the final closing and opening movement of said moving half-mould is an abrupt, not adequately slowed-down one, so that it may give rise to blows and clattering, - owing to the rapid wear-down of the mechanical organs and parts concerned (it should be noticed that these must be able to operate on a contmuous-duty basis over very long penods of time), the duration of the machine life is significantly affected, le reduced, thereby giving nse to immediate problems of planned maintenance and/or repair work, - the noise generated by the entire system controlling and actuating the movement of the moving half-mould is in general quite high and tends to further increase owing the the above cited wear-down effect, - since the moving half-mould must perform an alternating opening and closing movement at a relatively high rate, vibrations are generated which tend to be transferred to the entire structure of the plant, and this has obviously a negative impact on the duration and the operation of the machine organs involved, furthemore, the final opening and closing phase of the moulds is an extremely short and therefore strongly accelerated phase, and this of course contributes to an mcreased level of the so mduced vibrations, - for such accelerations to be obtained, over-sized movement control and driving organs must be used, but this fact not only has a negative effect on the level of the vibrations, but also, due to the greater extent of wear-down caused, to the ability of ensuring the desired precision standards over adequately long penods of Based on these considerations, it therefore is a mam purpose of the present invention to provide a blow-mouldmg apparatus of a plant for producmg hollow bodies, as well as the operating principles and manners thereof, allowing for the productivity thereof to be mcreased through an accelerated handling of both preforms and finished containers, without mcumng any of the afore cited drawbacks, which is capable of bemg easily implemented with the aid of readily available techniques and means and therefore is reasonably low-cost, reliable and preferably capable of bemg integrated with a preform production stage arranged upstream This aim, along with further features of the present invention, is reached m a blow-mouldmg apparatus having the charactenstics as recited in the appended claims, and may concretize itself in definite parts and arrangements of parts, as this can be more readily understood from the detailed descnption of a preferred embodiment that is given below by way of non-limiting example with reference to the accompanying drawings, m which: - Figure 1 is a side vertical-section view of a pair of half-moulds according to the present invention, as shown at a closmg angle enabling the preforms to be .introduced therein, - Figure 2 is a side view similar to the above one, however with the same half-moulds shown m a minimum opening position thereof enabling the blow-moulded container to be removed therefrom; - Figure 3 is a schematical view of the path, as seen from above, followed by a pieform to enter and to come out of a pair of half-moulds in a book-like open aiiangement accoiding to the pnoi ail, - Figure 4 is again a schematical view of the path, as seen fiom above, followed by a piefoim to entei and to come out of a pan of half-moulds accoiding to the present invention, - Figure 5 is a vertical front view of the half-moulds m their opened state, m the exact moment when the blow-moulded contamer starts to be removed therefrom, - Figuie 6 is a schematical top view of the geometry and the mutual arrangement of a plurality of moulds according to the present invention - Figuie 7 synthetically illustrates a comparison between two diagrams repiesentmg on a honzontal scale the time requirements for cairying out ta pieform moulding phase according to the prior art and the present invention, respectively, - Figuies 8 thiough to 1 ate views of as many positions of the moving half-mould, and the i elated actuation organs, from a fully open to a My closed position thei eof, - Figures 8A through to 1 A are schematical views of the locations on which forces concentrate, as well as the axes along which said forces acting on the actuation organs of Figures 8 through to 12 concentrate, - Figure 13 is a schematical view of the positions of the fundamental pomt vectors and the force vectors acting on the actuation organs of Figure 8, with the mould in an open state, Figuie 14 is a diagi ammatical view of the position characteristics of the moving half-mould with lespect to the position of the actuation pin from a reference position thei eof A mam peculiai featuie of the present invention lies m the use of pairs of half-moulds adapted to blow mould pi eforms 1 m view of converting them into finished containeis 7, wheiein said half-moulds aie essentially arranged as lllustiated m Figui es 1 2 and 6 showing lespectively a schematical side vertical-section view of a pair of half-moulds m a partially open state, a schematical side vertical-section view of the same half-moulds m an almost fully open state, and a schematical top view of the anangement of the moulds 24, 25, 26 according to the piesent invention m a fully open state, as m the case of the moulds 24 and 25, and a fully closed state, as m the case of the mould 26 On the outei periphery of a per se known lotatmg cai ousel 10 theie are applied a plmahty of pans of half-moulds, wheiem - one of such half-moulds 2ιs fixed and firmly joined to said carousel, and is furthei arranged on a vertical plane, with its respective half-cavity facing outwardly and l adially onented with lespect to the cai ousel 10, - the othei half-mould 4 is movable with a lotary motion about an axis X arranged on the honzontal plane and hinged on a rotation device (not shown) so that, when laised into its closed position it is moved into coupling exactly with the matching fixed half-mould that is fiimly joined to said carousel In this way, therefore, the need actually anses for only the moving half-mould 4 to be actuated into closing and opening, since the other half-mould 2 is fixed and substantially firmly joined to the cai ousel In this connection, a look should be taken at the illustrations appearing m Figures 3 and 4 In particular, the illustration in Figure 3 can be seen to show, m an extremely schematical manner, a top view of the path a followed by the preform, which is then moulded into a finished container, with respect to the two half-moulds 21 and 22 according to the prior art, and therefore both movable, as shown m an open state thereof From this Figure it can be readily noticed that said path a must mclude a deep slop g pattern in order to enable the preform to first slide mto the half-moulds and then move out therefrom as a finished contamer. As compared with such a situation, the illustration appearing in Figure 4 shows, agam m a schematical manner, a corresponding top view of the path b followed by the preform, which is then moulded mto a finished contamer, with respect to the fixed half-mould 2 and the movmg half-mould 4 Although sketched m a rather simplified form, this illustration does not fail to immediately stress the pomt that the path b of the preform runs along an arc of circumference without any apparent diversion, or anyway a curvilmear trajectory without any pomt of inflection that is likely to slow down the movement of the preform container along the path thereof and to add to the complexity of the construction of the motion control organs The lme portions indicated at H, L, M, P and R m the diagram of Figure 7 respectively show the preform insertion time, the half-mould closmg time, the blow moulding time (dashed l e), the half-mould re-openmg time, and the finished contamer removal time, according to the pnor-art On the contrary, with the process according to the present invention, owing essentially to the closmg phase of the movmg half-mould occurring partially at the same time as the preform insertion phase, as well as the opening phase of the same movmg half-mould occurring partially at the same time as the finished contamer removal phase, a reduction m the overall cycle-time of the blow moulding tools can be obtamed Smce the above cited improvement allows for the preform insertion phase H' to partially overlap the closmg phase L' of the sole movmg half-mould, such a time during which said two phases are earned out simultaneously is identified as time T° which must necessarily be deducted from the overall cycle time Furthermore, after the related blow moulding phase M', which has necessarily an unaltered duration, the opening phase P' of said movmg half-mould is carried out Even in this case, the possibility exists for the subsequent removal phase R' of the finished contamer to be caused to start earlier, by a time T 1 , before the mould is fully open, so that this partial overlappmg of the openmg phase P' of the movmg half-mould and the removal phase R' of the finished blow-moulded contamer again brings about a further reduction m the overall cycle time by such a penod dunng which said phases are so overlappmg, le by the above cited time T 1 In practice, the total cycle time is reduced from a value T x indicated m Figure 7 to a lower value T c , smce T c = T x - T° - T ! Only a slight mention is made here of the fact that the actual blow moulding time Ts, which is also identified by a dashed portion m both diagrams of Figure 7, is common to and unaltered for both blow moulding processes, so that it is not affected, le modified by the present mvention However, the advantages brought about by the present mvention do not end here In fact, a further improvement of the mvention itself can be easily obtamed m the manner that is described below with particular reference to Figures 1 and 2 Referring to Figure 1 , it can be noticed that the introduction of the preforms in the blow moulding half-moulds, le the exclusive movement of the preforms towards said half -moulds, can be accomplished through just a partial openmg of the movmg half-mould 4, le when the openmg angle is an angle I that is smaller than the maximum openmg angle, which thing is on the contrary not possible m those cases m which both half-moulds are movable owmg to the particular kinematic mechanisms that would be needed to such a purpose, as anyone skilled m the art is well aware of This furthermore leads to the advantage of the overall plant to be capable of beinf adjusted to the length of the preforms, smce it can be easily appreciated that shorter preforms require a smaller openmg angle and, therefore, shorter mould msertion times Similarly, as better illustrated m Figure 2, the movement for the removal of the finished blow-moulded contamer can be started before the movmg half-mould is fully opened, provided that the trajectory S of the lower edge of the same contamer does not interfere with the movmg half-mould. A further advantageous improvement of the present mvention lies m providing an appropnately curved guide element 15, illustrated in Figures 4 and 5, arranged m a stable manner in such a position as to be able to mtercept the path of the preform neck from the trajectory b, and to assist it m its movement of insertion m the respective cavity of the corcesponding fixed half-mould 2 As far as the technical improvements in the organs controlling the movement of the movmg half-mould are concerned, reference should be made to Figures 8 through to 1 , as well as the corresponding schematics appearing m Figures 8A through to 1 A The latter can be seen to symbolically represent the fundamental pomts of application of the action and reaction forces on the organs of the plant, the vectors representmg such forces, and the direction of action thereof From the illustrations m the above cited Figures it can be noticed that said actuation organs of the movmg half-mould 4 compnse - a first class lever provided with arms 52 and 53 separated by a fulcrum FI, whose power and resistance pomts are located at the extreme ends of said two arms, le at Pl and Rl respectively - a third class lever provided with respective arms 55 and 56, a respective fulcrum F2, and respective power and resistance pomts at P2 and R2, - a ngid connecting member 54 that links the resistance pomt RI of said first class lever with the power pomt P2 of said third class lever, said resistance and power pomts bemg connected to the extreme ends of said connecting member pivotally, - an actuating member 51 provided with two end portions, the first one of which is connected to the power pomt PI of said first class lever The fulcra FI and F2 of said first class lever and said third class lever, respectively, are applied pivotally on respective distinct pomts of a structure 60 that is integral withor firmly jomed to said fixed half-moulds, furthermore, said movmg half-mould 4 is applied on the arm 56 of said third class lever opposite to the related fulcrum F2 with respect to the corresponding power pomt P2 The second extreme end 57 of said actuating member 51 is adapted to be movably actuated by a movmg member 58 on a plane that is orthogonal to the axis of rotation of the fulcrum FI of said first class lever The whole assembly of said levers, cormectmg members and actuating members is adapted to move, clearly m a synchronous and coherent manner smce each movmg member is linked to another member, between two respective extreme positions, m which one of such extreme positions corresponds to the full-open position (Figures 8, 8A and 12) of said movmg half-mould, whereas the other one of said extreme positions corresponds to the full-closed position (Figure 1 , 12A and 16) of the same half-mould Referring now to Figure 13, which illustrates the condition of the mould assembly in its fully open position it can be noticed that when said second extreme end 57 of said actuating member 51 is urged to start movmg in the direction m which said movmg half-mould 4 is caused to close, the vector VI of the force transmitted from said pomt of resistance RI of said first class lever to said rigid cormectmg member 54 has a component V2 m the direction od action od said cormectmg member, le along the straight lme joining RI with P2, wherem said component V2, if considered as bemg applied on said pomt of power P2 of said third class lever, mdicated at V2,l m the Figure, may be m turn broken down mto two mutually orthogonal components, one of which, le the one mdicated at V2,2 m the Figure, is onented towards F2 and acts so as to only compress the related arm 55, with practically no effect at all within the overall geometry, whereas the other component V2,3 is radial with respect to said arm 55 and therefore acts on the arm 56 supporting the half-mould 4, in such a manner as to cause said third class lever to rotate, thereby causmg said movmg half-mould to close As far as the spatial configuration and the possible components of the force vectors, the lever arms and the other connecting/actuating members, it has π practically been found that the most effective and logical arrangement thereof is obtamed when all of them are provided on a same plane, m particular on the plane shown m the Figures 8 through to 12 However, as anyone skilled m the art is capable of readily understanding, said vectors, members and components may also be arranged three-dimensionally, provided that they meet the pre-condition of their projections or components on a given, suitable plane reflecting the subsequent conditions illustrated m the Figures Figures 9 through to 11 illustrate subsequent dispositions of the whole assembly of said levers and said cormectmg and actuatmg members, along with the respective vectors, corresponding to some subsequent positions of said movmg half-mould 4 as it is moved mto closmg They are anyway readily understandable by all those skilled m the art, so that no further explanation needs to be given here m this connection Figures 12 and 1 A represent the situation when the movmg half-mould is fully closed This is a quite particular situation smce, further to representing a kind of end-of-stroke pomt, it also represents the condition m which the "toggle effect" shows up in all of its effectiveness In other words, this is the condition m which the clampmg force of said half-mould reaches its peak, le is maximized, while the angular displacement of said half-mould is at a minimum Use is anyway made also of other means, further to this fact, m order to ensure a fully stable clampmg of said half-mould. Reference should be made now to Figure 12 the pomt of resistance RI of the lever 52, 53 is m an articulated arrangement with respect to the cormectmg member 54, so that the arm 53 and said cormectmg member 54 are capable of rotatmg with respect to each other However, a further rotation thereof beyond a pre-established position is prevented by the presence of a mechanical or positive retamer (not shown) that really acts as a toggle, le enables two levers hmged on an extreme end thereof to rotate with respect to each other only up to a certain angle and not any further The geometnc configurations and the dimensions of the vanous members and components involved are so defmed as to make sure that, when such a limit stop position is reached, this position also comcides with both - the full-closed condition of the movmg half-mould against the respective fixed half-mould and - the particularly favourable condition created by the three geometncal sited identified by P2, RI and FI are aligned, as this is shown m Figure 1 A The advantageous character of such a circumstance has already been hinted at above and lies essentially m the fact that, m the fmal portion of the closmg path covered by the movmg half-mould, the force that is produced and can therefore be used to close and clamp said half-mould, is at its maximum, le reaches a peak In this case m fact, as this is most clearly shown m Figure 14 illustrating the openmg or closmg angle of the movmg half-mould m accordance with the progressive displacement of the movmg member 58, or rolling pm, the most favourable condition is obtamed m view of making the best possible use of the so-called "toggle effect", said condition bemg reached through the illustrated combination and association of the described leverages In a more detailed manner, Figure 14 can be noticed to emphasize how, in comspondence of the portion of curve mdicated at M at a certain progressive displacement of the device or rollmg pm 58, whose scale m the lower portion of the Figure is a linear one, a rotation is obtamed with a progressively decreasing mcrement of the angle between the members 54 and 55 until an angle of 0° is eventually reached between said members 54 and 55 m correspondence of a value of approx 1 m the abscissa The particular pattern followed by said curve m correspondence of the above cited pomt M, which corcesponds to said movmg half-mould bemg closed, and also of the pomt H at the opposite end of the same curve, which corresponds to the full-open position of said half-mould, ensures a movement of the same half-mould with progressively slowed-down accelerations and decelerations towards the respective end-of-stroke positions thereof, until practically a condition of zero acceleration is reached when the half-mould approaches said respective end-of-stroke positions thereof Such a movmg pattern of said half-mould translates mto a number of significant practical advantages, le. a noticeable reduction m vibrations, the prevention of the movmg half-mould from bumping when movmg mto its end-of-stroke positions, and the possibility for said movmg device to be actuated with the help of simple, reliable and accurate means that are furthermore durable, le well resistant to wear-down smce they are not subject to the action of "forces". This condition is further strengthened by the fact that, immediately upon said movmg half-mould having so been moved mto its fully closed position, the same half-mould is automatically clamped m such a position with the help of such supplementary external means as readily conceivable by all those skilled m the art, said means bemg linked to the pins 41 , 42 that are firmly jomed with the fixed half-mould and the movmg half-mould, respectively It will of course be appreciated that when it is stated that the geometrical sites identified by P2, RI and FI are aligned, as this is shown m Figure 12A, this is meant to be understood m the broadest sense of the word, smce this is actually mtended to mean that, m order to ensure the desired "toggle effect", it is sufficient for the axes of rotation of the pins centered on P2, RI and FI to be not only parallel, but also arranged on a same plane The continuous operation of the described assembly for altematmgly openmg and closmg the movmg half-mould can be obtamed through a conespondmg to-and-fro movement of the movmg device or rollmg p 58, wherem such a movement can be easily obtamed by means of a contmuously rotatmg cam device adapted to control the movement and the position of said rollmg pm m full synchrony with all other devices, mechanisms and actuators that altogether ensure the various phases for openmg the half-mould, mtroducmg the preform, closmg the half-mould, blow moulding said preform, openmg the half-mould and simultaneous removal of the finished contamer A further advantage of the present mvention, as exemplified m the illustrated embodiment thereof, derives from the fact that if, as just stated above, the alternating to-and-fro movement of the movmg device or rolling p 58 is actuated by two rotating cams, preferably on the same vertical axis of rotation of the carousel 10 m Figure 6, the limited weardown effect that unavoidably takes place between the actuatmg surfaces of said rotatmg cams and said rollmg pm has only a very limited impact on the openmg and closmg accuracy of the moulds This fact brings about the remarkable benefit denvrng from the possibility for the maintenace or re-adjustment of said cams and therewith associated organs to be earned out at quite extended intervals, without incurring any loss m processmg precision A confirmation of the fact that the weardown effect of the cams, and possibly also of the therewith associated rollmg pm or movmg device, has only a very limited impact on the precision of the end-of-stroke positions of the movmg half-mould can be simply obtamed by having again a look at Figure 14, m which it can m fact be observed that the condition actually occurs m which, m front of a certainly non-negligible displacement, le oscillation of the rollmg pm about said pomts M and H, the angle of rotation of the movmg half-mould is almost nihil and practically negligible As a result, if such an oscillation is due to weardown, this practically has no significant effect on the precision of the end-of-stroke positions of said movmg half-mould

Claims: CLAIMS 1 Apparatus for blow moulding hollow plastic bodies comprising - a plurality of pairs of mutually joinable half-moulds capable of bemg opened and closed, associated to an appropriate rotary apparatus (10) carrying said half -moulds, - support devices for carrying the preforms corresponding to said half-moulds, - a preform feeding mechanism adapted to supply an orderly sequence of preforms held at an appropriate blow-mouldmg temperature mto the respective pairs of half-moulds associated to said rotary apparatus which are to this purpose kept m their opened position - a retrieval device adapted to remove the finished contamer from the respective pair of half-moulds after the openmg thereof, - an openmg and closmg mechanism adapted to close the half-moulds after the passage thereof through the position of the preform feeding mechanism, and to open them before the passage thereof through the position of the finished-container removal mechanism, charactenzed m that - said pairs of half-moulds are constituted by a fixed half-mould (2) and a movmg half-mould (4) that is capable of bemg opened from and closed agamst said fixed half-mould 2. Apparatus according to claim 1 , charactenzed m that said fixed half-moulds are essentially linked to said rotary apparatus (10) 3. Apparatus according to claim 2, charactenzed in that said fixed half-moulds (2) are arranged m a substantially vertical position, and that the respective movmg half-mould (4) is adapted to be closed by accomplishing a substantially rotary movement about a honzontal axis of rotation 4. Apparatus according to claim 3, charactenzed in that said pairs of half-moulds are adapted to be opened and closed in an orderly sequence so as to be able to receive a respective orderly sequence of preforms. 5. Apparatus according to claim 3 or 4, characterized in that an appropnate guide member (15) is provided m correspondence of the position m which the preform is inserted m the cavity of the respective fixed half-mould, m which said guide member is adapted to facilitate both the separation of the preform from the respective support and the insertion thereof m said respective cavity 6. Apparatus according to any of the preceding claims, characterized m that saidopening and closmg mechanism of any of said movmg half-moulds (4) compnses - a first class lever (52, 53) and a third class lever (55, 56), - a structure (60) firmly associated to said fixed half-moulds (2), - a cormectmg member (54) that joins the pomt of resistance (RI) of said first class lever with the pomt of power (P2) of said third class lever, said resistance and power pomts bemg pivotally connected to the extreme ends of said cormectmg member, - an actuatmg member (51) provided with two extreme ends, of which the first extreme end is connected to the power pomt (PI) of said first class lever (52 53), - the fulcra (FI , F2) of said first class lever and said third class lever bemg pivotally applied on respective distmct pomts of said structure (60) firmly associated to said fixed half-moulds, and - said movmg half-mould bemg applied on the arm (56) of said third class lever which is opposite to the related fulcrum (F2) with respect to the correspondmg power pomt (P2) 7 Apparatus according to claim 6, charactenzed m that the second extreme portion (57) of said actuatmg member (51) is adapted to be forced by a movmg device (58) mto displacing on an orthogonal plane with respect to the axis of rotation of the fulcrum (FI) of said first class lever 8. Apparatus according to claim 6 or 7, charactenzed m that said levers and said connecting and actuatmg members are adapted to move between two respective extreme positions, in which one of said extreme positions conesponds to the full-open position of said movmg half-mould, whereas the other one of said extreme positions corresponds to the full-closed position of said movmg half-mould 9 Apparatus according to claim 8, characterized m that when said second extreme portion (57) of said actuating member is driven m the sense of starting the closmg displacement of said movmg half-mould (4) from the full-open position thereof, the vector (VI) of the force transmitted from said resistance pomt (RI) of said first class lever to said cormectmg member (54) has a component (V2) in the direction of said cormectmg member which, when applied on to said power pomt of said third class lever, has m turn a respective second component (V2,3) that is oriented so as to mduce a rotation of said third class lever m the closmg direction of said movmg half-mould 10 Apparatus according to any of the preceding claims 6 to 9, characterized m that m said fully closed position of said movmg half-mould (4), said power pomt (P2) and said fulcrum (F2) of said third class lever, as well as said resistance pomt (RI) of said first class lever are either aligned or the respective axes of rotation are parallel and lie on the same plane 11. Apparatus according to any of the preceding claims 6 to 10, charactenzed m that said movmg device (58) is adapted to be driven mto altematingly displacing between two extreme positions correspondmg to the conditions m which said movmg half-mould is fully open and fully closed, respectively, by means of a cam device rotatmg about an axis that is orthogonal to the axes of rotation of said two levers 1 . Apparatus according to any of the precding claims 6 to 11, charactenzed in that m said full-closed position thereof there is provided a retaining device adapted to prevent said movmg half-mould (4) from further rotatmg beyond said full-closed position 13. Apparatus according to any of the precding claims 6 to 12, charactenzed in that selectively actuatable means are provided, which are adapted to prevent said movmg half-mould from rotatmg back towards the open position from said full-closed position

Inventors: ZOPPAS MATTEO, ZOPPAS, MATTEO
Applicants: SIPA SPA, ZOPPAS MATTEO, SIPA S.P.A., ZOPPAS, MATTEO
Application year: 1999
Main classification: B29C49
IPC codes: B29C49