DE1956453U - DEVICE FOR MANUFACTURING HOLLOW BODIES FROM THERMOPLASTIC PLASTIC. - Google Patents

Description

Utility model registration

of the company

Kautex plant Reinold Hagen, Hangelar via Siegburg (RhId.)

Device for the production of hollow bodies from thermoplastic

Plastic.

The invention relates to a device for producing hollow bodies made of thermoplastic material, especially bottles, from a z. B. tubular or band-shaped preform, consisting of a two-part or multi-part blow mold and a blow mandrel that can be moved in its longitudinal direction in relation to this, the outside a socket carries, which is attached to the blow mandrel longitudinally displaceable and rotatable.

When using devices of this type, the following procedure is generally followed: that first the mold is closed around the tubular preform in the majority of cases, whereupon the blow pin is then closed - ± n ~ -e ± nes of the ends of the hose section is introduced to to inflate the latter. During the insertion, the bottle neck, or at least a partial area thereof, is press-formed at the same time. After expanding by means of the pressure medium supplied through the blow nozzle and sufficient solidification of the hollow body produced in this way the mold is then opened to eject the hollow body.

Generally due during manufacture at the free end of the bottle neck a material waste, which is caused by an on the detached blow pin

circumferential edge while moving the mandrel into one The end of the hose section is pinched off. However, this material waste usually remains with a thin plastic skin connected to the hollow body. It is often torn off by hand. The editing by any cutting or milling tools is not necessary. For this reason, it is possible to use the ring-shaped to separate the blow pin surrounding material waste using a sleeve from the hollow body, which concentric the blow pin surrounds and is rotatable with respect to this. The arrangement is made so that the sleeve together with the blow pin after closing the shape is moved towards the latter. After completion of the shaping process, the bushing, the end of which is on the mold side, is inserted into the Excess material is pressed in, given a rotary movement, by which the excess material is carried along and removed from the bottle neck or the like. of the hollow body is torn off.

Although this device is tearing off what is located on the hollow body Makes waste piece by hand superfluous, it has some disadvantages. These are due, among other things, to that. with -,. the known device, the separating bushing together with the Blow pin in djle shape and thus inserted one end of the preform will. It can be assumed that both for compression molding of the bottle neck and for squeezing off the excess material - to on the remaining thin film - on the one hand, and on the other hand, a specific one in each case for pushing the separating sleeve into the excess material Force is required, which must be transmitted via the blow pin. It is not possible in the known device, this to set both forces independently of each other. This has an unpleasant effect in particular when, with regard to the properties of the

Any changes to the material to be processed and the dimensions of the preform occur, which also have to be taken into account accordingly when dimensioning the aforementioned forces. Such a change can e.g. B. occur when the weight of the finished container and thus possibly the wall thickness of the preform can be increased or decreased.

Another difficulty with the known device is that the waste piece, since it is generally widened compared to the Hollow body represents a material thickening, not is cooled quickly enough or not sufficiently. Since the cooling time for the finished product is a significant part of the entire work process omitted, the aim is to keep the cooling time as short as possible. This may mean that the finished Hollow body is already ejected from the mold at a point in time at which the slug is not yet completely solidified with tar. if Both parts, as often happens, are ejected from the mold together or stripped from the blow pin, then the case can arise that the slug comes into contact again with the finished hollow body and sticks to it, so that the reject rate is thereby reduced is increased. While it is known to help avoid these difficulties to blow cooling air onto the piece of waste protruding outwards from the mold during the shaping process. However, are special design measures are necessary for this, which represent an additional effort and also complicate the device.

The invention is based on the object of the aforementioned disadvantages to eliminate. In particular, she wants to ensure that the forces that are necessary for the compression molding of the

Bottleneck and squeezing off the excess material on the one hand and, on the other hand, are necessary for pressing the separating sleeve into the excess material, adjusted and possibly independently of one another can be regulated. Furthermore, a ■ Sufficient cooling of the piece of material to be separated from the bottle or the like take place.

To solve this problem, the invention first proposes that the Bush is displaceable independently of the movement of the blow pin in the direction of the blow mold. The arrangement is expediently made in such a way that that the socket is provided on the outside with an extension, preferably in the form of a circumferential collar, which at least on Part of its circumference from one in the longitudinal direction of the blow pin and retractable bracket is included, for which a special drive is provided. First, the blow pin is inserted into the open end of the preform, whereupon, if necessary with only one very slight delay, the socket is pressed against the scrap piece and into it. This is then followed by a Rotational movement of the socket, which separates the waste piece from the bottle neck. The socket with one or more in Provided longitudinal grooves in which wiper pieces "" are arranged, opposite which the bushing in the longitudinal direction is movable. These stripper pins can take part in the rotary movement of the bushing. The latter can go through one to the outside directed approximately radial extension of the socket transferred to this are, the extension penetrated into a parallel to the blow mandrel guide, which is in the circumferential direction of the socket or tangentially is displaceable for this purpose and thereby takes the socket with it. ESine in the circumferential direction Any displacement of this guide has the advantage that, with regard to the size of the angle by which the bushing is rotated,

there are no restrictions.

The end of the socket facing the blow mold is advantageous with a Knurling, provided with tooth-shaped projections or dglo, which in the pressed in excess material of the preform to be processed will. In this way, a form-fitting connection is achieved between the bushing and the waste piece, so that the latter during the rotary movement the socket is also taken along. The teeth can be undercut to achieve a form fit acting in the longitudinal direction of the blow pin, bent or otherwise designed in a suitable manner, so that after completion of the separation process when the socket is back in its Starting position, that is, moved into its position remote from the blow mold, the scrap piece is taken from the socket until it is detached from the bushing by the wiper pins. The same goes for but also in the event that the severed piece of material is not taken from the socket. In that case it would be on the blow pin sit and move it away from the mold through the stripper pins be stripped from the blow pin.

According to a further essential proposal of the invention, the possibly thickened — the end area of the bushing, the excess material of the Preform against the opposite boundary surface of the mold press. This ensures that a relatively large amount of heat is extracted the waste material is drained into the mold and the thickened part of the bushing will. This is supported by the fact that the wall thickness of the waste piece is increased by the pressing of the material between the mold and the bushing decreases so that the heat can be dissipated faster. To improve this effect, it is advisable to the socket near its end facing the shape and the opposite-

to provide the areas of the blow mold with channels in which a coolant, z. B. water, flows.

The invention avoids all the advantages of the known device which the euchse is moved together with the actual blow pin in the direction of the blow mold. The one consisting of a blow pin and socket The overall arrangement is much larger in diameter than the actual blow pin. If both parts, i.e. blow pin and socket, are inserted together into the open end of the hose, as is the case with the known device, then must be under Under certain circumstances, the diameter of the tube can be chosen larger than necessary taking into account the diameter of the actual mandrel and the shaping to be effected by this mandrel were. Otherwise, there is a risk that the socket acting simultaneously with the blow pin in the open hose end causes a material shift that can adversely affect the actual shaping process. In the device according to the In the invention, however, there is the possibility of initially only the blow dome without moving the bushing in the direction of the preform and the blow mold and only move the socket towards the waste material afterwards. This ensures that any influences, pressures, / Material displacements or the like. -, which are exerted by the bushing, remain without influence, since at the time when this Pressings take place, practically already the shape of the bottle neck is completed by the actual blow pin. From this it follows that when applying the invention there is no need is to take into account the presence of the socket when choosing the diameter of the hose to be processed in some way.

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An exemplary embodiment of the invention is shown in the drawing. Show it:

Fig. 1 is a side view of a blow pin with an adjoining one

Blow mold, partly in section,
FIG. 2 shows a section along line 2-2 of FIG. 1.

The blow pin 10 formed in the usual way is close to his lower end, at which it merges into a conical extension 10a, provided with a shoulder 11 through which the face of the bottle neck 12a of the bottle 12 is formed, which is otherwise within the blow mold consisting of two mold halves 13a and 13b a pressure medium from a preferably tubular preform is widened. The supply of the pressure medium takes place through a bore 14 in the blow mandrel 10. The shoulder 11 delimiting the outside circumferential edge 15 squeezes in the course of the lowering movement of the mandrel 10 into the blow mold 13a, 13b into the excess material 16 of the Preform from, so that the abiali piece 16 finally only over a very thin film with the bottle neck 12a of the bottle 12 connected is.

The downward movement of the mandrel 10 practically ends when the circumferential edge 15 on the flad delimiting the inlet of the mold 17 rests.

A sleeve 18 is arranged around the blow pin 10, which at its lower, thickened end 19 is provided with teeth 20. The socket 18

is longitudinally displaceable and rotatable with respect to the mandrel 10. The Teeth ' ; The thickened end 19 of the bushing serves to flatten the material forming the waste piece 16 between the bushing and the upper boundary surface 21 of the mold 13a, 13b Waste piece 16 is made possible on the mold and the socket 18. In order to be able to dissipate the heat as quickly as possible, the two halves of the mold and the thickened area 19 of the socket 18 are provided with channels 23 and 24 for a coolant. '· * »

The socket 18 is provided with a circumferential collar 25, on which one or more brackets 26 engage, which are displaceable parallel to the longitudinal axis of the mandrel 10. Two brackets 26 offset from one another by 180 ° are expediently provided. Through these brackets Zi u the z. B. can be moved by a hydraulic or pneumatic cylinder not shown in the drawing, the up and down movement of the sleeve 18 is controlled. The latter is still

provided with longitudinally extending grooves 27 in which stripping pins 28 are arranged. The latter are connected to one another via a common circumferential collar 29 which is guided in a stationary holder 30. The stripping pins 28 take part with the collar 19 in the rotational movement of the bush 18. This also has a radial extension 31 _} which protrudes between the two parts of a guide 33. This causes the rotary movement of the bushing 18 in that it is displaced, taking along the radial extension 531, either perpendicular to the plane of the drawing or also in the circumferential direction of the bushing 18, that is to say in a circular manner. The length of the guide 33 parallel to the mandrel 10 results from the extent of the up and down movement that the bush 18 performs.

The blow pin described above is used in such a way that, after the two mold half parts 13a and 13b have been closed around the preform, the blow pin 10 is lowered into the mold and the upper, open end of the preform is lowered. The aforementioned separa- ^occurs: voltage of the excess material '16 through the pinch-off edges 15 and the opposite surface 16 of the mold. Simultaneously with the lowering of the mandrel or immediately thereafter, the bushing 18 is shifted downward so that the teeth 20 are pressed into the scrap piece 16. Then, after a certain amount of cooling of the waste piece 16 has already taken place, a rotary movement of the socket 18, by means of which the waste piece 16 is torn off from the bottle neck 12a away from the blow mold 13a, 13b, generally after the blow mold has been opened, and as the teeth 20 lift the scrap piece 16 with them, the pins 28 scrape it off once the lower end of the sleeve 18 has reached those pins However, it is also possible to provide the mandrel 10 immediately above its shoulder 11 with a circumferential groove 32 into which material of the scrap piece 16 is pressed in the course of the downward movement of the mandrel into the blow mold. so that ^K as a result creates a form-fitting connection between the mandrel 10 and ': the scrap pieceΊ6, which is effective in the longitudinal direction of the mandrel. In this case, the mandrel 10 would move the vo Rher take away waste piece 16 separated by the bushing 18, whereby it would then also be removed from the mandrel by the stripper 28.

The prescribed embodiment provides for the blow pin with to arrange the associated facilities above the blow mold. It is of course also possible to use the mandrel with the associated parts to be provided below the blow mold, so that in this case the

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The molding is inflated from below and the waste piece is also created below would.

With £ & 35 a ring is referred to, which is placed on the blow pin 10 near the lower end of the same. It is used to allow any air inclusions during the compression molding of the bottle neck to escape along the parting line between this ring 35 and the actual mandrel 10. ■,

I J

Claims (8)

P.Ä. 556 239 * 25.10.66 J * - 10 - Protection claims 1. Device for producing hollow bodies from thermoplastic Plastic, especially bottles, from a z. B. tubular or band-shaped preform, · consisting of a two-part or multi-part Blow mold * - and one of these opposite in its longitudinal direction movable Blow pin, ^ which carries a bush on the outside, which is opposite to the blow pin Is attached longitudinally displaceable and rotatable, characterized in that the bushing (18) is independent of the movement of the blow pin (10) is displaceable in the direction of the blow mold (13a, 13b). 2. Device according to claim 1, characterized in that the socket (18) on the outside with an extension (25) is preferably in the form a circumferential collar is provided, which can be pushed back and forth at least on parts of its circumference by one in the longitudinal direction of the blow pin (10) Bracket (26) is included, for which a special drive is provided. 3. Apparatus according to claim 1 or 2, characterized in that the Bushing (18) is provided with one or more longitudinally extending grooves (27) in which stripping pins (28) are arranged, which relative to the socket (18) is displaceable in the longitudinal direction. 4. Device according to one of the preceding claims, characterized in that that the bush (18) has an outwardly directed approximately radial extension (31) which is inserted into a parallel to the blow pin (lo) extending guide (33) engages, which is displaceable in the circumferential direction of the socket (18) or tangentially dazil. - 11 - 5. Device according to one of the preceding claims, characterized in that that the end of the bushing (18) facing the blow mold (13a, 13b) with knurling, with tooth-shaped projections (20) Or the like. Which engage in the excess material (16) of the preform to be processed. 6. Front *? E £ device according to claim 5> characterized in that the teeth (20) to achieve a longitudinal direction of the blow pin (10) acting form fit undercut, bent or the like. Are. 7. Device according to one of the preceding claims, characterized in that that the possibly thickened end area (19) of the bushing (18) the excess material (16) of the preform against the opposite (21)
lying boundary surface / the mold (13a, 13b) is pressed. 8. Device according to one of the preceding claims, characterized by dadunch, that the bush (18) near its end facing the mold (13a, 13b) and the opposite regions of the blow mold (13a, 13b) are provided with cooling channels (23, 24).