FI62482C - APPARATUS FOR CONTAINER FORMNING AV ETT GJUTSTYCKE AV THERMOPLAST - Google Patents

Description

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Patent- och regi «t« rrtyrelMn Ameiun uthgrf och utUkrtften pubiicw ^ d 30.09.82 (32) (33) (31) Pyy4 «« y · ωο «Μ« »- Begird prlerit * 07.01.75 27.06.75 Luxembourg (LU ) 71598, 72853 (71) Solvay & Cie, 33, rue du Prince Albert, B-1050 Brussels,

Belgium-Belgium (BE) (72) Marc Obsomer, Brussels, Luc Bodson, Grez-Doiceau, Edmond Michel,

Brussels, Belgium-Belgien (BE) (jh) Oy Kolster Ab (5 ^) Apparatus for continuous forming of a casting from thermoplastics -Apparatur för kontinuerlig moldning av ett gjutstyeke av thermoplast

The invention relates to an apparatus for the continuous production of a casting from an oriented thermoplastic, by means of which rather high production speeds can be achieved.

It is previously known to make hollow objects with improved mechanical properties from thermoplastics by expanding and finally shaping blanks at the temperature of molecular orientation. These preforms are generally used at a temperature below the crystalline melting point of the thermoplastic used to make them.

Numerous methods for making oriented hollow articles on an industrial scale from thermoplastics have been proposed. One suitable method is based on making blanks by blowing a tubular casting in a preforming mold, heating these blanks to a suitable temperature to orient them, and then placing these blanks in molds where the final casting is done by blowing.

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One apparatus suitable for carrying out the method is described in U.S. Patent 3,767,747.

This apparatus consists of two casting units, each with a preforming mold and a mold used for final blowing. These molds are placed on both sides of the tubular casting device. Each unit moves alternately so that its preforming mold is placed under the injection molding head and then under the blow hoses, which are also arranged on both sides of the injection molding device.

However, with this type of equipment, only low production speeds can be achieved due to the successive movements of the casting units, the limited number of molds, and the compulsion to keep each preform in its mold long enough to thermally heat this preform.

An apparatus has now been developed for the continuous production of oriented tubular castings from thermoplastics using blow molded blanks as a starting material, whereby very high production speeds can be achieved with this apparatus.

The invention relates, in particular, to an apparatus for continuously forming a casting from a thermoplastic, the apparatus comprising an apparatus for producing a tubular continuous casting from a thermoplastic, a preform blowing machine into which said tubular casting is continuously fed and whose molds are end-to-end so as to engage a primary rotating support. capable of making discrete blanks with their necks cast in their final shape, a device for removing castings from the neck of these blanks, a thermal cleaning device for heating the blanks to their optimum orientation temperature, a pre-blowing machine with a plurality of molds fitted to a second rotary carrier, and a transport device into a pre-blown machine by passing the blanks through a burr remover and a thermal purifier.

The invention is characterized in that the device for transporting the blanks consists of a terminating chain with carriers arranged in such a way that they support the blanks below their already shaped neck.

The blanks carried by the endless chain are generally cylindrical in shape. Their base can be arbitrary in shape. These blanks may end at an edge, such as in hairmast paste tubes, or this base may also be hemispherical, such as in test tubes used in chemical laboratories. Their neck part already has the final shape of the neck of the finished hollow object, and their central part is approximately cylindrical.

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The supports have upright spaces, at least at their tops, which are also generally cylindrical in shape, the diameter of these spaces being suitably slightly larger than the diameter of the central part of the blanks, so that these spaces loosely enclose these blanks to avoid damage. These spaces are suitably bottomless so as not to damage the bottoms of the blanks. In this case, there may be an annular bulge in the neck of the blanks. Such a bulge is not a disadvantage in the blanks, since the bulge must in any case be made on the final hollow objects in order for them to be closed with a stopper.

According to a particularly preferred embodiment of the carriers, these carriers are formed by two jaws which can be spaced apart and which are designed so that when closed they form a bottomless cylindrical space. The jaws are spaced apart to make it easier to lower the preformed blanks into their carriers and to make them more accessible for transfer to a pre-blown machine. These jaws press between the central part of the blanks. The height of the jaws is not critical.

The carriers are attached to the endless chain at regular intervals. The endless chain, suitably with vertical shafts, can be easily supported, transported and steered by means of gears. In addition, this chain allows the chain to be positioned correctly in relation to different devices and machines. However, any other conveying device can be used, e.g. a toothed belt capable of performing the same functions as an endless chain.

It is obviously advantageous to select the distances between the carriers and the travel speed of the endless chain so that all the blanks can be transferred from the blowing machine of these blanks to the pre-blowing machine, and that each turn of the chain includes one such blank between the two machines. It is thus essential that both the blowing machines and the endless chain are capable of the same production speed.

The blanks are removed from the blowing machine of these blanks at regular intervals. In this case, the carrier must be ready to receive the blank each time such a blank occurs. The removal of the blanks and the course of the carriers must therefore be completely synchronized. To achieve this synchronization, of course, the dimensions of the various elements must be chosen appropriately.

On the other hand, it must be possible to transfer the blanks to the carriers when the rotating carrier of the machine blowing these blanks rotates at different speeds. This result can be conveniently achieved by the endless chain being driven by the same motor which 4 62482 uses the rotating support of the blank blowing machine.

In this way, the linear forward speed of the endless chain is always varied in proportion to the rotational speed of the machine blowing the blanks, and the endless chain can thus properly perform its function in the area of this machine regardless of the rotational speed of this machine.

Of course, the pre-blowing machine must also be designed to receive and blow the preforms successively conveyed by the endless chain.

The correct positioning of the pre-blowing machine relative to the endless chain requires that there is a proper synchronization in this feed range between the bypasses of the endless chain carriers and the bypasses of the blank receiving means for feeding these preforms to the pre-blowing machine.

This result could be achieved by using a pre-blowing machine via an endless chain. However, the rather high inertia of this machine would force recourse to an oversized endless chain. However, according to the invention, this requirement is best met by using a pre-blowing machine by means of the same motor which drives the blank blowing machine, the drive being effected by means of suitable gearboxes.

According to a preferred preferred embodiment, both rotating carriers of the blowing machines are thus driven by a single motor which also uses an endless chain to convey the blanks. By operating in this way, the equipment can be made to work properly in combination, and its production speed can be changed by performing a single adjustment, namely the adjustment of a single drive motor.

According to this preferred embodiment of the invention, the endless chain is provided with tensioners, and this chain is operated indirectly and twice via both blowing machines.

The applicant has stated that the synchronization between the endless chain and the machines is not always achieved if both of these machines do not participate in the operation of the chain but are driven directly by the motor or by a single blower using this chain. In fact, small variations have been found to occur periodically at the stage when the chain carriers pass through the area of the blowing machines. These deviations are mainly due to the clearances that can occur between the different moving elements of the equipment, as well as to the temperature variations of the endless chain when this endless chain together with the blanks passes through the thermal comparator.

By proceeding as described herein, the positions of the carriers can be adjusted in the area of both blowing machines. The small temporary variations in the travel speed of the endless chain in the area of both blowing machines 5 62482 can be canceled and compensated by the automatic shift of the tensioners. This avoids the risk of chain breakage. In addition, limit switches can be used that automatically stop the motor in the event that a tensioner moves above the allowable limit.

The number of tensioners is suitably two, and these tensioners are suitably located in connection with the flow between the two points of use of the endless chain.

In the case of a blank blowing machine, it is important that the successive molds are connected as tightly as possible, since a continuous tubular casting is fed into these molds and thus the gap between two successive molds leads to material loss.

Instead, in the final blow molding machine, the molds may be spaced apart because each mold is intended to receive a separate blank.

The apparatus according to the invention will be explained in more detail below on the basis of some practical embodiments thereof. Of course, this description does not limit the scope of the invention in any way. The explanation is presented on the basis of the accompanying drawings.

Figure 1 is a schematic plan view of a device according to the invention.

Figure 2 shows a schematic perspective view of a hardware transport system.

Figure 3 shows a partial section of a fixed preforming mold half. This figure shows the hollow blow needle control device.

Figures 4 and 5 show a side and top view of a part of an endless chain carrying blanks. These figures show one of the supports with which this chain is equipped.

Figure 6 shows a partial section of a fixed preforming mold half. This figure shows an alternative embodiment of the ejection device.

According to Fig. 1, the apparatus according to the invention comprises a device 1 for producing a continuous tubular body, a first rotating turntable 2 with a horizontal axis, which supports interconnected preforming molds arranged at the ends so as to receive a continuous tubular blank, a mold emptying device 3 which alternately removes blanks transferring them to the articulated jaws of successive carriers mounted on the endless conveyor chain 4. The endless chain 4 conveys the blanks alternately through a device 5 which removes casting burrs from the neck of these blanks, as well as through a thermal ratio space 6.

62482 The endless chain 4 then shows the preforms cleaned and thermally proportioned from their castings to be properly transferred to pre-blown molds fitted to a second rotating carrier 7 »having a perpendicular axis of rotation.

As will be explained in more detail below, the apparatus can be supplemented by a blank cooling device 8 placed between the die removal device 5 and the thermal cleaning device 6, and an discharge furnace 9 »following the final blowing device 7 and receiving directed hollow objects removed from this blowing device.

The endless chain 4 has a dual use in the region of the mold removal device 3 or the mold removal device 5 and in the region of the preform-blowing mold transfer device 10. The endless chain 4 is further provided with two tensioners 11 and 12 located in connection with the running between the two applications of the endless chain.

As can be clearly seen in Figure 2, the drive mechanism of the various moving parts of the apparatus is provided by a rotating shaft 13 »driven by a speed control gear 14, which thus constitutes the sole power source for the entire drive of the apparatus.

Thus, the first rotating pivot 2, in which the crown 15 is schematically illustrated, is directly rotated by the gear 16. This gear 16 is wedged onto the rotating shaft 13 so that it interlocks with the gear 15 ·

The gear 17, which is also wedged onto the shaft 13, drives a device 3 via a chain 18 and an angular transmission device 19, which transfers the cast blanks to the conveyor chain 4.

The second gear 20, which is also wedged onto the shaft 13, drives, via a chain 21 and an angular transmission device 22, a device 5 which removes castings from the neck of the blanks.

The last gear 23, which is also wedged onto the shaft 13, drives the intermediate shaft 26 via a chain and a gear 25.

This PTO shaft 26 drives, via an angular transmission device 27, on the one hand a gear crown 28 attached to the second rotating carrier 7, the gears 29, 30, 31 and a chain 32, and on the other hand forms a first drive chain drive 4 acting on the shaft 33, gears 34 and 35, via a chain 36 and a gear 37, which gear is in grip with the chain 4 ·

The conveyor chain 4 is also used in the area of the blank blowing unit. This use can be achieved either by means of a device 5 for removing castings or a device 3 for transferring billets, or also by means of both of these devices.

The path traveled by the conveyor chain 4 is determined by the spur gears 3Θ, and 7 62482 two tensioners 11 and 12 are arranged in connection with each segment between the two actuators of the endless chain.

The position of these tensioners is not critical, as long as they are each located in connection with a segment of the endless chain 4 located between the actuators. Thus, in Figure 1, these tensioners 11 and 12 are located in different positions.

The arrows in the figure indicate the direction of rotation or displacement of all actuators.

It can thus be clearly seen that a single motor 14 drives all the moving members of the apparatus via the shaft 15, which ensures complete synchronization during operation.

In addition, the endless chain 4 is operated at two points located in the areas where the chain receives the cast blanks and the chain delivers these blanks to the pre-blowing machine, so that this chain is perfectly synchronized at its points of contact with other members of the apparatus.

In Figures 1 and 2, the practical details of the various elements of the apparatus are not drawn for clarity. These details are explained in more detail below.

The injection molding press 1 of the continuous tubular casting shown schematically in Fig. 1 does not differ much from the previously known devices.

However, it is necessary to select an injection molding machine whose production capacity adapts to the large production capacity of the apparatus according to the invention, which apparatus must be fed by the injection molding machine in order to produce oriented hollow objects. The injection molding machine must also have a system for programming the wall thickness of the pressed continuous tubular casting.

The first rotary pivot 2 is, as already mentioned above, provided with end-to-end interlocking molds, the inner cavity of which provides the desired shape of the blank.

According to the described preferred embodiment, this pivot driven by the crown 15 rotates at a constant speed about a horizontal axis and shows the various molds mounted on its circumference alternately in the region of a continuously injection-molded tubular casting tangentially to this rotating support.

The blank blowing machine may have the same general construction as the rotary blowing machine for hollow objects described in Belgian patent 723 419 filed in the name of the applicant on 6.II.1968 »except that each mold forms only a single blank and not two neck-connected blanks.

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The rotating pivot 2 thus consists of a series of evenly spaced arms arranged radially in a plane perpendicular to the rotating axis. At the end of each such arm is a mold assembly suitably formed of a fixed mold half attached to the shaft and a movable mold half hinged to this fixed mold half. The device has eccentric guides for alternately closing the molds at the stage when their rotational movement moves them to the area of the continuous tubular casting fed by the injection molding to lock the molds in the closed position, to control casting that cast blanks can be removed.

The shaping surface of each mold suitably provides a shape of the blank having a closed dummy neck and a hemispherical base, as described in French Patent Application No. 74, 09 380 filed in the applicant's name 15 · 3 · 1974, and shown in Figure 1 of this patent application.

Devices for removing castings from the bottom of the blanks, e.g. the devices described in this same French patent application, may be suitably arranged between the interconnected molds with which the rotary turner is provided. The eccentrics control these die extraction devices in such a way that separated blanks can be produced directly, the hemispherical base of which is completely free of castings.

In addition, the mold cavity of each mold may suitably correspond to the shape of the blanks described in French Patent Application No. 74.05 461 filed in the name of the applicant on February 14, 1974, and which is particularly illustrated in Figures 1-5 of this patent application. Removing the molds from the bottom of these blanks does not cause any problems because this bottom appears as a straight edge.

The diameter of the mold space of the molds, and thus the diameter of the blanks produced, is only slightly larger than the diameter of the tubular casting used as the starting material, so that the radial elongation of this tubular casting remains less than $ 20 during casting.

In fact, it is advantageous at this stage to limit the elongation of the casting, since no molecular orientation develops here due to the relatively high temperature of its thermoplastic.

The blank is suitably shaped by blowing with a hollow needle. This needle is connected to a source of pressure fluid and punctures the tubular casting at a point outside the desired molded neck, i.e. in the part of the casting from which the closed casting neck is to be formed, which is subsequently removed.

The hollow blow needle is suitably mounted on a movable guide assembly located on the side of the fixed mold half, the movements of this combination being controlled by the rotational movement and eccentrics of the movable support supporting the molds.

Figure 3 shows a preferred alternative embodiment of this device.

As shown in this figure, the fixed mold half 39 »having a mold space 40 reproducing the shape of a blank having a hemispherical base has a blowing device, in particular a hollow movable needle 41 with a conical base 42. This needle 41 is inserted into a space in the guide assembly 43 which the bottom has a conical portion corresponding to the conical base 42 of the needle. The needle 41 is held at the bottom of the space by a compression screw 44. At the end of this screw there is a central channel located in the extension of the central channel of the needle and connected to the screw walls by radial channels 45 · The diameter of the compression screw head 44 is further such that an annular space is formed between the circumference of the control assembly 43 and the compression screw head 44. The passage 47 in the control assembly 45 opens into this annular space 46. This passage 47 is connected via a control valve (not shown) to a source of pressure fluid. on the carrier in a direction perpendicular to the axis of the fixed mold half 39 is provided by the rotational movement of the control lever acting in two directions. This control lever is mounted on a carrier 49 fixed to a fixed mold half 39 · The second lever arm 50 provided with a idler wheel 51 may move, e.g., not shown by fixed eccentrics during the rotational movement of the rotating carrier supporting the blanks, while the second arm 52 acts on the guide assembly 48. 43 positions. As shown in this figure, the needle is positioned to penetrate the zone 55 of the mold space 40, which limits the formation of a closed dummy neck to the molded blank. Thanks to the needle mounting system, the blow needle can be quickly changed if necessary, since only the compression screw 44 needs to be unscrewed to pull the needle out of its position in the control assembly 45. The new needle is inserted simply by pushing the needle from its tip into the space and reinserting the compression screw 44. Thanks to the chamber 46 and the radial channels 45, the needle 41 does not have to be placed in any special position in its space.

10 62482 This detail shown, as well as the structure and operation of the apparatus for blow molding preforms, are practically similar to those described in the aforementioned Belgian patent no: 723 419, so that these details need not be further explained.

The removal of the molded blanks from the molds and their removal during the opening of the molds is suitably carried out by means of the mold removal device described in Belgian Patent No. 772 264, filed in the applicant's name 7 · 9 · 1971. Blanks which are removed by the mold pushers and arms of this device However, due to the co-operation of the associated lifting devices, it is not lowered onto the carrier, as described in this Belgian patent no. 772 264, but these blanks are simply transferred to carriers formed by articulated jaws arranged in connection with an endless conveyor chain 4. This transfer does not cause any particular synchronization problem, since the endless chain 4 is used in the vicinity of the mold removal device 3, which in turn is driven by the rotating plate of the blank blowing machine. This ensures complete synchronization of the movements of the lifting members of the mold removal device and the movements of the supports formed by the articulated jaws mounted on the endless chain 4.

The dimensioning of the deburring device, the distance between the endless chain supports and the transmission ratio of this demultiplexing device to the endless chain are suitably selected so as to cause the blanks to move at the same linear speed at the exact time they leave the deburring device, and the endless chain takes them with it. This gives the equipment a completely impulse-free operation.

Figures 4 and 5 of the accompanying drawings illustrate an endless chain segment provided with a carrier for articulated jaws.

As shown in these figures, the articulated jaw flap 54 is mounted on a plate 55 »which is attached to the loops of the endless chain 4. This pivot supports two movable jaws 56 and 57 articulated to pivot pins 58 and 59 attached to the plate 55. · The spring 60 tends to keep the jaws in the closed position. The second jaw 56 is provided with a lever arm 61 with a guide idler roller 62. In addition, two interlocking gears 63 and 64 are attached to each jaw at the height of the pivot pins.

The opening of the articulated jaws is controlled by the encounter between the guide roller 62 and a non-shown fixed eccentric placed in the path of this roller. This eccentric 11,62482 causes the jaw 56 to pivot under the action of the lever arm 61, and this pivoting movement, via the gears 63 and 64, causes the second jaw 57 to pivot in the opposite direction. The eccentric is positioned so that the jaws are in the open position at the stage when the mold removal device has removed the blank from its blowing device, and the jaws close abruptly by the spring 60 at the moment the mold removal device has released the blank.

The arms of the mold remover grip the blanks just below the neck. When the arms are released, these blanks fall under the influence of gravity into a space formed by the pre-closed jaws of their carrier. The blanks remain in place due to the annular bulge in their neck.

During the opening of the preform molds, it is advantageous that the molded preforms remain adhered to the fixed mold half so that the device for removing the mold obtains a grip on them. Applicant has found that this condition can be easily and reliably used by keeping the blow needle 41 immersed in the mold space 40 of the fixed mold half until the mold is partially opened. In this way, the needle actually retains the blank in the fixed mold half.

This result can be achieved, for example, by adjusting the eccentric controlling the retraction of the needle 41 so that it acts on the lever 50 only after the corresponding mold has been partially opened. In this case, the blowing is obviously best stopped before the mold opens.

This condition can likewise be fulfilled by means of the removal devices described in the aforementioned Belgian patent 723 419. · In this case, the removal member is in its rest position retracted relative to the height of the bottom of the mold space.

Figure 6 of the accompanying drawings illustrates another method which also uses such removal members. The member 65, shown in this figure in its rest position, is located in the plane of the bottom of the mold space 40 of the fixed mold half 39, and the upper part of this member has a hemispherical rounding section. When the blank 66 is blown, a part of the thermoplastic will penetrate the cavity 67 formed by this cut, so when the mold then opens the blank remains attached to the fixed mold half 39 · Removing the blank 66 does not pose any problem, since the removing member has pushed the blank neck into the mold removal device. the arm supporting these pliers will detach the blank from the recess of this removing member.

The preforms removed from the mold, which have passed to the articulated jaw carriers 44 resting on the endless conveyor chain 4, then pass through 12 62482 through an extruder removing the mold, which cuts off their dummy neck.

This step can suitably be carried out by means of a deburring device described in Belgian patent 675 915 * filed by the applicant on 17 December 1965. * In such a device a fixed knife cuts the casting or dummy neck while causing the blanks to move along the knife and rotate about its longitudinal axis.

The transfer movement can be achieved by means of a rotating plate with idler rollers having a suitable profile corresponding to the Vale neck profile. These blanks are then held at the height of their necks and passed through a device for removing castings while rotating themselves between two idler rollers and a suitably shaped fixed guide.

The endless chain 4 can rotate the plate at such a speed that the transfer speed of the blanks is exactly the same as the linear forward speed of this chain. Alternatively, this plate can be driven directly by the same motor that drives both blowers. In this case, the plate can operate the endless conveyor chain at a speed that adapts to the rotational speed of the blowing devices. This use can supplement or replace the use provided in the region of the mold removal device, in which case the latter device can in this case be disconnected from the endless chain.

It will thus be seen that the use of an endless chain in the region of the first blowing device can be achieved either by means of a mold removal device or by means of an extruder removing device, or by any other drive device connected to a motor using both blowing devices.

The rotating plate suitably has idler rollers profiled to fit the false neck profile of the blanks, and the fixed guide is likewise profiled in this way so that the blanks are positioned in the correct position when cutting their castings.

The blanks can be kept in their carriers as they pass through the deburring device. They can also be lifted slightly during this passage so that they no longer rest in the annular bulge of their neck.

In order to prevent the blanks from continuing the rotation to which they are subjected during the removal of the castings, it is obviously advantageous in this case not to be firmly held by the articulated jaw carriers on the endless chain 4, at least during their passage through the removal device. The articulated jaws are suitably made for this purpose in such a way that, in their closed position, they only loosely surround the bodies of the blanks, these blanks being suspended between the jaws and held by their molded necks. To facilitate the rotation of the blanks, a fixed eccentric can be used which is profiled so as to cause the articulated jaws to open at the time the blanks enter the deburring device and which causes these jaws to close around the billets as they leave the deburring device. In the latter case, the retaining rollers and the circular fixed guide in connection with the rotating plate must be profiled so as to retain the blanks at the height of both their dummy neck and their neck during removal of the castings, so that the blanks remain retained between these elements even after the dummy neck has been completely cut. , so that the articulated jaw supports are again gripped by them at the stage when the billets leave the mold removal device. However, this modification is not necessary in the case where the eccentric is profiled so that it again closes the support jaws at the exact time when the neck castings have been cut.

When blowing blanks in the molds of the first blowing machine, these molded blanks are apparently cooled, e.g., by circulating cooling fluid in the walls of the molds so that the blanks can be removed from the molds without changing their shape. In addition, since these blanks must be subjected to a lateral treatment, the cooling during the casting of the blanks must be adjusted so that the average wall temperature of the preforms removed from the molds is within the temperature range suitable for the subsequent directing of these blanks. For this reason, the outer wall of the blank, which is in contact with the mold-space wall of the mold during casting, is cooled more than the inner wall.

'If, for example, the cooling fluid is room temperature water, the temperature of the outer wall of the blank during removal from the mold is about 30 ° C, while the temperature of the inner wall remains close to the injection molding temperature. As a result, the blank thus has a temperature gradient in the direction of the blank thickness in the mold removal step, which can extend from room temperature (outer wall) to injection molding temperature (inner wall).

During the subsequent transfer of the blanks, this gradient tends to level off, so that the final average temperature of the mold wall is constant or virtually constant throughout the thickness of the wall.

For each thermoplastic used, it is obviously advantageous to adjust the cooling of the molds of the blanks 62482 14 so that this final average temperature is later adapted to the subsequent orientation treatment.

However, given the high manufacturing speed of the blanks, especially when using relatively thick tubular castings, it may prove insufficient to cool the molds to finally reach a sufficiently low average temperature so that efficient orientation is possible.

In order to increase the cooling efficiency during the casting of such blanks, a rather cold fluid, such as expandable liquid nitrogen, can be flushed into the interior of the blanks at the end of the blowing, which is injected through a hollow needle.

However, this technique proves to be quite inefficient due to the small volume of the blank. In doing so, the internal cooling is further limited to the zone of the dummy neck, so that subsequent removal of the neck may become more haphazard.

In order to enhance the cooling of the blanks, if necessary, the applicant has found it advantageous to resort to internal blowing of the blanks with cold fluid after the false necks have been removed, and this is a feature of the invention.

This result can be achieved by inserting hoses connected to a source of a rather cold fluid, such as expanded liquid nitrogen, into the blanks cleaned from their necks. By adjusting the insertion and / or retraction rate of the hoses and the immersion depth of these hoses, a temperature gradient can also be obtained along the axis of the blanks, which in some cases may prove advantageous.

This subsequent cooling treatment can suitably be performed in a circular carousel, as schematically shown in Fig. 1, item 8. This carousel is driven by a blank transfer chain or the same motor that uses the blowing equipment. In this case, the movement of the cooling hoses mounted in connection with the carousel can be controlled by means of fixed eccentrics.

If desired, the outer wall can likewise be cooled by blowing cold fluid.

After the preforms have passed through the deburring device and possibly by internal blowing through the cooling device, the preforms supported by the endless conveyor chain 4 pass through a thermal cleaning furnace 6, the temperature of which is selected so that the final blowing can be carried out at a slightly lower or slightly higher temperature. . Thus, the temperature of the thermal blasting furnace is adjusted experimentally so that the blanks leaving this space have an optimum temperature for their orientation, and that their temperature is practically the same at every point in their thickness.

After leaving this annealing furnace, the blanks are placed in final blow molds mounted on a second rotating carrier, the structure of which is arbitrary.

This latter pivot suitably rotates about a vertical axis and supports those casting units which are formed by both axially separable mold halves, so that these casting units do not necessarily have to be connected to one another.

The preforms are suitably transferred to the blow molds by means of blow hoses attached to a rotating carrier which adheres to the preforms in their molded neck at the time the profiled fixed eccentric jaw with articulated jaws opens, the movements can be controlled, for example, by means of fixed eccentrics.

As mentioned above, full synchronization of this movement is achieved due to the fact that the rotating support of the pre-blowing object is driven by the same motor that drives the rotating support of the blank blowing machine and the endless conveyor chain is driven by an actuator connected to this pre-blowing machine.

In the case of a pre-blowing machine, it is also advantageous for the equipment to operate without pulses, so that the design and the rotational speed are selected so that the linear speed of the hoses is the same as the speed of the endless chain.

After each pre-blow mold is closed, the corresponding blow hose provides the final shape of the proportioned blank by blowing.

The length of the blanks is suitably less than the length of the desired oriented objects, whereby the ratio of the length of the final hollow objects to the length of the blank can vary between 1-5 · This allows the blanks to be stretched both axially and radially during blowing, causing biaxial orientation. This results in excellent mechanical properties.

The blow hoses can be suitably provided with a central movable piston which ensures the correct centering of the blanks during pre-blowing.

After blowing and cooling, the oriented hollow objects are removed during the opening of the blow mold and fall under the influence of gravity.

According to a preferred alternative embodiment, this step can be facilitated by pulling back the blow hose at the beginning of the opening of the corresponding mold 16 62482 so that the molded hollow object associated with the blow hose is retained by the upper shoulders of the mold and thus released from the hose. Release from the hose can still be ensured by spraying more blowing fluid during the return of the hoses or by causing the centering piston in the hoses to move more.

Oriented objects that have left their molds may, if necessary, be subjected to an emission treatment in an emission furnace, in which case the temperature of this furnace is kept lower than the temperature at which the bending takes place under load. The Applicant has found that this emission treatment in particular can improve the resistance of oriented hollow objects to stress-induced cracking.

Claims (11)

An apparatus for continuously refining a thermoplastic molding comprising a device (1) for producing a tubular continuous thermoplastic molding, a machine (2) which blows blanks and in which said tubular molding is continuously fed and whose molds (39) are end-to-end in the same line, so as to join a first rotary holder, by means of which separate blanks, the throat of which is molded in its final form, can be made, a casting degree removal device (5) from the shaft of these blanks, a heat conditioner which heats the blanks to their optimum orientation temperature, a pre-blown machine (7) with a plurality of molds arranged in a second rotary heater, and a conveyor (4) for transferring the blanks from the blower (2) to the blown machine (7) by passing the blanks through the deburring machine (5) and through the heat conditioning device (6), n - characterized in that the conveying device for the blanks is constituted by an endless chain (4) with similarly arranged brackets (54), that they carry the blanks under their already formed necks. 1 Q 62482 2. Apparatus according to claim 1, characterized in that the endless chain (4) is driven by the same motor (14) which drives the rotating holder (2) for the machine which blows the blanks. Apparatus according to claim 1, characterized in that the pre-blown machine (7) is driven by the motor (14) which drives the machine for blowing the blanks. 4. Apparatus according to claim 1, characterized in that the machine (2) which blows the blanks, the endless chain (4) and the finished blowing machine (7) is driven by the same motor (14) via a control shaft (13). Apparatus according to claim 4, characterized in that the endless chain (4) is driven indirectly on the same thread by the machine (2) which blows the blanks and by the finished blowing machine (7). Apparatus according to claim 5, characterized in that the chain (4) is provided with tensioners (11, 12). Apparatus according to claim 6, characterized in that the number of tensions (11, 12) are two and that they are distributed on each segment of the endless chain (4) located between the chain's two driving points.