EP0090933B1 - Apparatus and method for perforating or perforating and cutting tubes - Google Patents

Abstract

1. A method of perforating or of perforating and cutting the walls of hollow bodies made of plastic, said bodies being capable of running true or of presenting rotational symmetry, in particular reels such as textile tubes, characterized in that the hollow body (2) to be perforated is rotated and the points where it is to be perforated are repeatedly punctured by a plurality of needles (8) and the puncture action is repeated in succession at a frequency and with a rapidity such that the tips of the needles (8) in each case repeatedly entering holes being formed heat themselves by friction and make perforations from initially small holes.

Description

The invention relates to methods for perforating or for perforating and cutting concentric or rotationally symmetrical hollow plastic bodies on their walls, in particular of winding carriers such. B. textile sleeves. The invention further relates to devices for performing the method.

DE-A-25 06 512 discloses a textile sleeve made of a thermoplastic material which is designed as a rotationally symmetrical hollow body and which can be deformed in the radial and also in the axial direction. The textile winding can be subjected to a wet and / or heat treatment, perforations being provided in the wall of the textile sleeve for the permeability of the liquor.

In addition, there are numerous cases in which pipe sections have to be cut from an initially longer blank. This also applies if sleeves can first be blown during their production, with continuous production of pipes or intermittent production of blown hollow bodies being known, in which case the base and the attachment piece for the blown-in air must then be cut off subsequently.

In the case of such textile sleeves, no residues may be left when the perforations are made, which could severely disrupt subsequent processes in which the perforated sleeves are required. Such residues could e.g. B. occur if the perforations were punched out.

The invention is therefore based on the object of providing a method of the type mentioned at the beginning, with which plastic hollow bodies can be provided in a simple manner quickly and economically and without residues with sufficiently large perforations.

A solution to this problem is that the hollow body to be perforated is rotated and that repeated puncturing is carried out with several needles at the locations of the hollow body to be perforated and the punctures are repeated so often and so quickly that the respective holes are repeatedly immersed Heat the tips of the needles by friction and make perforations out of small holes.

It is already known from DE-A-27 49 894 to use heated pins when perforating foils. However, expensive heating devices are required, which also require their own energy supply. The method according to the invention, on the other hand, uses the frictional heat generated during the piercing and repeated dipping into the perforations in order to make an initially small perforation into a perforation of sufficient size without any perforation residues. Special heating devices with energy supply are avoided.

It is particularly expedient in the method according to the invention if a rotating body which is also equipped with the needles and is also rotated is set in counter-rotation with respect to the rotated hollow body, the circumferential circle encircling the needle tips being immersed in the surface of the hollow body to be perforated and the speed being selected in this way that the needle tips repeatedly immersed in perforations are heated by friction.

This results in a kind of toothing between the hollow body to be perforated and the rotating body or needle carrier, which is filled with the needles, even during the first insertion. In this way it can be very easily achieved that needle tips repeatedly hit holes in the course of several revolutions. Too little or too much heating can be avoided by selecting the speed.

In such a method, in which a plurality of needles are distributed around the circumference of one or more needle carriers, the hollow body to be perforated can be rotated by the rotation of the needle carrier (s) and the temporary form-locking needles piercing it. In this case it is sufficient if only at least one of the needle carriers is provided with a drive.

A further development of the invention of considerable importance can consist in rotating a continuously or intermittently blown hollow body and cutting it off at its later end faces, preferably simultaneously with or after a perforation process. In this way, hollow bodies, in particular textile sleeves of a predetermined length, can be cut off from the respective blank, which can either be a longer tube or a bottle-shaped blown part. In a particularly advantageous manner, the rotation of this blank can be used both for the above-described method for perforating and for cutting off.

Another solution to the problem mentioned at the outset can be a method of the generic type, which is characterized in that the hollow body to be perforated is advanced axially during perforation and is repeatedly punctured with needles at the locations of the hollow body to be perforated and that the punctures repeated so often and so quickly in succession that the tips of the needles, which plunge several times into the resulting perforations, heat themselves and make perforations out of small perforations. Instead of rotating the hollow body, the hollow body is moved axially in this case.

This method can be designed such that rotating rotating bodies with needles in the direction of movement of the Hollow body to be rotated about axes of rotation arranged transversely to the direction of movement of the hollow body, the circumferential circle extending through the tips of the needles immersed in the outer surface of the hollow body to be perforated and the speed being selected so that the tips of the needles repeatedly immersed in perforations are caused by friction be heated. In this solution, too, this results in a kind of interlocking between the hollow body to be perforated and the needle carrier covered with the needles. In this case too, too little or too much heating can be avoided by the choice of the speed of the needle carrier.

A further independent solution to the above-mentioned object can consist in a method of the generic type in that the hollow body to be perforated is rolled during perforation over a stationary field with needles, so that needles are repeatedly pierced at the locations to be perforated, and by the unwinding speed, the punctures are repeated so often and so quickly that the tips of the needles, which penetrate the perforations several times, heat themselves by friction and produce the perforations. The hollow body can gradually be pressed deeper onto the needles as it rolls off.

With the aforementioned various solutions to the problem, it is possible to avoid too little or too much warming by the choice of speeds. However, since this could limit the production speed under certain circumstances, it can be an expedient development in all of the aforementioned solutions if the self-heating needles are blown on and / or treated preparatively, in particular wetted with a coolant, to adjust their temperature. The liquid coolant can be applied, in particular brushed, by atomizing or as dripping oil. These measures make it possible to set the temperature, which cannot be precisely determined by frictional heat.

The invention is also based on the object of providing the most practical and simple devices for carrying out the method according to the invention. Claim 11 specifies a device with a device for holding and rotating a hollow body and with a rotating body as a tool carrier as a solution to this problem. Through the combination of features of claim 11, the repeated insertion of the needles at the same position of the wall of the hollow body can be carried out simply and conveniently.

As a holder for the hollow body, rotatable support rollers acting on its outer circumference can be provided. The or the rotatable needle carrier can be pivotally mounted relative to the hollow body. As a result, the needles can be disengaged when the hollow body is finished, while at the same time the insertion of a new hollow body is made easier.

It should also be mentioned that the cross section of the needle can be profiled. This enables various desired forms of perforation to be created.

The support rollers and / or the needle carrier (s) can be adjustable to the diameter of the hollow body to be perforated and the needle carrier (s) can be radially adjustable against the interior of the hollow body during processing. As a result, the device can be adapted to different dimensions of hollow bodies.

A further modification of the device according to the invention can consist in that the needle carrier is designed as a needle roller of preferably at least the length that corresponds to the length of the area of the hollow body to be perforated, optionally the length of the entire hollow body.

An embodiment of the device according to the invention of considerable importance can consist in that at least one knife blade or a cutting tool for separating a sleeve with a predetermined length from a blank is arranged in at least one intermediate space between the support rollers arranged on the circumference for the rotating hollow body. It is particularly expedient if a plurality of knives arranged at a distance from one another are provided for the separation of individual sleeves from pipes or blanks and if rings equipped with needles and arranged at a distance from one another are also provided for the rotary drive of the hollow bodies.

In particular for larger hollow bodies, a plurality of needle rings and / or needle rollers can be provided for the rotary drive and the perforation. These can thus drive the hollow body like a gear, the needles being able to penetrate so deeply that the desired perforation is produced at the same time.

At least one of the support rollers can be connected to a drive. This can either support or replace a rotary drive based on needle wheels or needle rollers.

A further expedient embodiment of the device according to the invention, which can also be used in the devices to be described subsequently, can consist in that, in addition to the needle roller or the like, preferably a channel for blowing air with openings directed against the needles and / or parallel to this is provided for the supply of a cooling liquid. As a result, in addition to the temperature control by a certain speed, overheating of the needles with the aid of a cooling medium can be avoided. To apply a liquid cooling medium to the Needles can be provided with at least one brush with its bristles engaging at least in the area of the needle tips.

Further refinements of the device, in particular with regard to an ejector and the cutting knife, are the subject of claims 23 to 26.

For perforating hollow bodies with a profiled surface, the support rollers can have an analog counter-profile. Especially textile sleeves according to DE-A-25 06 512 should be able to have a wavy surface in order to allow their surface to be flexible in the radial and axial directions. When perforating such textile sleeves, it is expedient if the aforementioned measure is taken, namely that the support rollers have corresponding counter-profiles.

In this case, the support rollers for hollow bodies having annularly arranged profiles can have zones with groups of stronger counter profiles and those with weaker counter profiles. This allows such a profiled textile sleeve to adapt to the profiling of the support rollers even with slight dimensional deviations, since, above all, the weaker counter-profiles do not fully engage in the sleeve profiling and thus give them some freedom of movement in the axial and / or radial direction.

Claim 32 characterizes a further device for solving the problem of creating an expedient and simple device for carrying out the method mentioned at the beginning. The combination of features of claim 32 results in a device in which an axial movement of the hollow body is carried out during the perforation.

The axes of these needle wheels are arranged at right angles to the advance of the hollow body to be perforated and distributed around its circumference for a hollow body of any cross-sectional shape. In particular, with their axes slightly oblique to the feed and to the axis of the hollow body, pinwheels can also produce perforations lying one behind the other in a helical shape.

A again modified device, which is used to carry out the method according to claim 7, is characterized in that fixed, in particular in one plane, needle fields are provided for perforating rotationally symmetrical hollow bodies, via which the hollow bodies to be perforated can be unrolled. With sufficient rolling speed can also be achieved with this device that the tips of the needles repeatedly enter the initially small perforations and heat up by friction, so that gradually large perforations can be formed without perforation residues. The number of needles entering the same perforation is chosen so large that the perforation reaches the desired size.

Embodiments of this device in which the workpiece is rolled over a needle field, in particular the mechanism used for rolling, expediently a conveyor belt or friction belt running obliquely against the needle field, are the subject of claims 35 to 39.

• Fig. 1 eine Stirnansicht und
• Fig. 2 eine Draufsicht einer erfindungsgemäßen Vorrichtung, mit der Hülsen erfindungsgemäß perforiert und/oder zurechtgeschnitten werden können,
• Fig. 3 in vergrößertem Maßstab in Stirnansicht eine Perforierwalze beim Bearbeiten eines von Tragwalzen gehaltenen Werkstückes,
• Fig. 4 eine der Fig. 3 entsprechende Darstellung einer Vorrichtung für Werkstücke größeren Durchmessers mit zwei Nadelwalzen od. dgl.,
• Fig. 5 eine Seitenansicht einer profilierten Tragwalze für ein mit breiten Weilen versehenes Werkstück,
• Fig. 6 eine der Fig. 5 entsprechende Darstellung, wobei das Werkstück eine engere, der Tragwalze entsprechende Profilierung aufweist,
• Fig. 7 bis 9 die Funktion eines mit einer elastischen Arbeitskante versehenen Auswerfers für ein Werkstück,
• Fig. 10 eine abgewandelte Vorrichtung bei der ein Werkstück mittels eines von oben an ihm angreifenden Transportbandes über ein feststehende Nadelfeld gerollt und dabei vorzügsweise immer stärker angepreßt wird,
• Fig.11 ein Ausführungsbeispiel, bei dem die Achsen der Nadelträger quer, insbesondere rechtwinklig zu der des Werkstückes stehen und
• Fig. 12 eine Stirnansicht der in Fig. 11 dargestellten Vorrichtung.

The invention is described in more detail below with its details that are essential to it, using the drawing. It shows in a partially schematic representation:

• Fig. 1 is an end view and
• 2 shows a top view of a device according to the invention, with which sleeves can be perforated and / or cut to size according to the invention,
• 3 is an enlarged front view of a perforating roller when machining a workpiece held by support rollers,
• 4 a representation corresponding to FIG. 3 of a device for workpieces of larger diameter with two needle rollers or the like,
• 5 is a side view of a profiled support roller for a workpiece provided with wide shafts,
• 6 shows a representation corresponding to FIG. 5, the workpiece having a narrower profile corresponding to the support roller,
• 7 to 9 the function of an ejector provided with an elastic working edge for a workpiece,
• 10 shows a modified device in which a workpiece is rolled over a fixed needle field by means of a conveyor belt acting on it from above and is preferably pressed ever more strongly,
• 11 shows an embodiment in which the axes of the needle carriers are transverse, in particular at right angles to that of the workpiece, and
• Fig. 12 is an end view of the device shown in Fig. 11.

A device designated as a whole with 1 is primarily used for concentric or rotationally symmetrical hollow bodies or workpieces 2, z. B. textile sleeves to perforate. In addition or instead of this, the device 1 can, according to the following description, also be designed or set up to separate such workpieces 2 from continuously or intermittently blown hollow bodies and, under certain circumstances, also to cut them into several sleeves or rings. Overall, the device 1 described below thus allows the production of rings or sleeves and / or their perforation.

The device 1 essentially shows a magazine 3 from which the blanks are guided by a guide 4 of the actual processing to be described in more detail below. The processing station is generally designated 5 in FIG. 1.

Following the processing station 5, approximately in continuation of the guide 4, a slide 6 or the like is arranged, via which the finished workpieces 2 can be removed. In Fig. 2 it is indicated that the workpieces 2 z. B. can reach a conveyor belt 7.

The processing station 5 is particularly important for the present invention, which is shown on an enlarged scale, particularly in FIGS. 3 and 4, for the case in which the workpieces 2 are to be perforated.

3 and 4, it can be seen above all that the device 1 and in particular its work station 5 have a holder for the workpiece 2 to be described in more detail and at least one (FIG. 3) or two (FIG. 4) with perforation needles 8 or the like. Carrier body 9 occupied. In this case, drive means are provided for repeatedly inserting the needles or styli 8 into the surface or wall of the hollow body 2. In this exemplary embodiment according to FIGS. 3 and 4, rotatable support rollers or rings 10 are provided as holders for the workpiece 2, and the needle carrier 9 is also a rotating body, the circumference of which is occupied by the needles 8 or the like is and whose axis of rotation runs parallel to the axes of rotation of the support rollers 10 of the hollow body 2 to be perforated and also to the axis thereof. It can be seen in FIGS. 3 and 4 that in the position of use, the needle carrier 9 with its axis is so close to the workpiece that the needles pierce and perforate the wall of the hollow body 2 at least after several revolutions.

In the exemplary embodiment, the needle rollers or rings 9 are pivotably mounted relative to the workpiece 2. One can clearly see a swivel arm 11 which is fixed in the device 1 via a joint 12 and can be swiveled upwards and then downwards again according to the double arrow Pf 1 from the position shown in FIGS. 3 and 4. It is clear that in the up position of this swivel arm 11, a workpiece 2 can be ejected after its processing or a new workpiece can be inserted for processing.

It should be mentioned that the needles 8 can have any profile if the perforation is to have a specific shape.

The support rollers 10 and also the needle carrier (s) 9 are expediently adjustable to the diameter of the hollow body 2 to be perforated, the needle rollers being adaptable by pivoting the swivel arm 11, while the support rollers with their axes can be mounted so as to be displaceable in parallel. It is advantageous that the needle carriers in particular have a drive and the carrier rollers can run along empty. However, it is also possible that at least one of the support rollers 10 has a drive, not shown.

2, a gear 13 or the like can be seen on an end face of the needle carrier rollers 9, which belongs to the drive of these needle rollers 9 or forms the drive. With this gear 13 further wheels or a chain or the like can then cooperate.

In Fig. 2 is also indicated that the needle carrier 9 can be designed as a needle roller of approximately the length that corresponds to the length of the area of the workpiece 2 to be perforated, in particular that of the entire workpiece 2. It is also indicated in Fig. 2 that z. B. three workpieces can be created and processed at the same time, in particular if 2 knife blades 14 or the like are arranged in at least one space between the support rollers 10 arranged on the circumference for the rotating workpiece. Cutting tools for separating a sleeve with a predetermined length are arranged. 2, for example, three perforated sleeves 15 can be formed from a blank during processing. In this case, a plurality of knives 14 arranged at a distance from one another can be provided for the separation of individual sleeves 15 from pipes or the like.

Both when separating individual sleeves and when perforating them, several needle rings and / or needle rollers 9 can be provided for the rotary drive and for the actual perforation, in particular for larger workpieces 2, these needle rings or rollers being distributed in the longitudinal direction one after the other and / or on the circumference of the workpiece could be.

The above-described device and in particular the work station 5 shown in FIGS. 3 and 4 allow a perforating process with heated needles 8 without these needles having to be connected to a heater. It is namely possible by the arrangement described above that repeated piercing or intervening at the points of the workpiece 2 to be perforated with one or more needles and that the punctures or interventions are repeated so often and so quickly that the several times in the heat the resulting perforations into the needle tips by the friction itself. Especially when perforating workpieces 2 made of thermoplastic plastic, the production of an actual perforation from an initially small puncture is supported and made possible at all by the heating or heating mentioned.

The hollow body 2 to be perforated is rotated in this perforation and the rotating body 9, which is filled with the needles 8, rotates in the opposite direction, so that a kind of toothing between the needles and the latter generated perforations is formed. It extends through the needle tip circumferential circle in the surface of the body to be perforated or even penetrates, the speed can be selected so that the needle tips repeatedly dipping into the same place generate the aforementioned frictional heat. It is not important that the same needle always hits the same hole, but it is only necessary that some needle always hits the same hole. As already mentioned, the rotating body 2 to be perforated can be rotated by the rotation of the needle carrier (s) 9 and the positive engagement that occurs in the process.

The self-heating needles 8 are expediently blown on and / or treated preparatively to adjust their temperature, in particular wetted with a coolant. A liquid coolant can be applied, in particular brushed, by atomization or as dripping oil.

For this purpose, one can see in FIGS. 3 and 4, in addition to the respective needle roller 9 or the like. Perforating tool, axially parallel to this, a channel 19 for blowing air with openings 20 directed against the needles 8. However, through this channel 19 and the openings 20 coolant can also be supplied.

Furthermore, both in FIG. 3 and in FIG. 4, a brush 21 can be seen in each needle roller 9 for applying a liquid coolant to the needles 8, said brush 21 engaging with its bristles 22 in the area of at least the tips of the needles 8.

It has already been mentioned that, in particular, the needle rollers 9 can be pivoted away from the workpiece when it is processed and is to be ejected. For this purpose, at least one ejector 23 is arranged opposite the attack of the needle rollers 9 and / or cutting knife 14 in the region of the workpiece 2. In Fig. 3 it is shown that a single ejector is sufficient for a smaller workpiece, while it is indicated in Fig. 4 that several ejectors 23 can be provided, especially for larger workpieces.

The design and operation of the ejector 23 can be seen particularly well in FIGS. 7 to 9. It is important that the ejector 23 is connected to the pivot bearing of the needle roller 9 or the like, or at least works synchronously in such a way that when the needle roller swings away 9 of the finished workpiece 2, this is acted upon by the ejector 23 between the support rollers 10 and is lifted out of the latter.

In the exemplary embodiment, the ejector 23 is designed as a ruler or the like, which is mounted approximately parallel to the workpiece 2 and has an elastic narrow side 24 which acts on the workpiece 2 and extends over at least part of the workpiece length. On its working edge or its narrow side 24, the ejector 23 in the exemplary embodiment has an elastic lip 25 which has a tube-shaped or loop-shaped cross section for adaptation to workpiece movements taking place during ejection. This makes it possible to gently eject even somewhat flexible workpieces. 7 shows the ejector 23 initially in the rest position. When ejecting the ejector 23 is moved in the direction of arrow Pf 2, whereby the workpiece is raised. Once this has overcome the upper support roller, it rolls away laterally over the slide 6, which is facilitated and supported according to FIG. 9 by the flexible hollow lip 25.

The lip 25 can follow this sideways movement somewhat according to the arrow Pf 3 of the workpiece and prevent it from falling back into the space between the support rollers. It contributes to the fact that this elastic lip 25 is resiliently elastic.

A side view of a schematic representation of the cutting knife (s) 14 can also be seen in FIGS. 3 and 4. It is clear that these cutting knives 14 with their cutting edge 26 are preferably at an acute angle to the surface of the workpiece 2 and preferably gradually during the cutting cut deeper into the workpiece and retractable after cutting while rotating. This retraction movement with simultaneous rotation of the workpiece can bring about an easy release of the knife from the cut formed by it and remove any burr that may occur. To separate short sleeves 15 or the like. Ring-shaped workpieces with knife blades 14 that are close to one another, these and in particular their cutting edges can be offset in height, so that they attack the workpiece at different times when it is inserted into the workpiece surface and do not deform it as far as possible and do not deform it generate great cutting resistance.

Another advantage of the pulling cuts produced by the knife blades 14 described and their cutting edges 26 and the still ongoing rotary movement of the workpieces when the knife blades are pulled out of the cut is that the cutting edges can sharpen the blades again and again, so that the cutting process to a certain extent is self-sharpening.

FIGS. 5 and 6 show that for perforating and / or severing workpieces 2 with a profiled surface, the support rollers 10 can have an analog counter-profile. 5 shows an example in which a strongly profiled support roller 10 engages a workpiece with relatively wide shafts.

FIG. 6 shows a solution in which the support roller 10, which is also shown in FIG. 5, for annularly arranged profififications 27, workpieces 2 zones 28 and 29 with groups of has stronger counter-profiles 30 and those with weaker counter-profiles 31. It can be clearly seen how the stronger profiles 30 fully engage in the profiles 27 of the workpiece, while the weaker counter profiles 31 only partially protrude into the profiles 27, so that the workpiece can adapt well to the support roller in the event of inaccuracies.

A modified embodiment of a work station for perforating tubes 2 of any shape in cross section is shown schematically in FIGS. 11 and 12. Here, at least one needle wheel, in the exemplary embodiment a plurality of needle wheels arranged at an angle to one another on the circumference of the hollow body 2 to be perforated, the axes of rotation of which are transverse is arranged to the feed direction of the workpiece 2 indicated by the arrow Pf 4. These needle wheels 32, several of which are arranged one behind the other in such a way that their needles 8 can also repeatedly enter the same perforations, cause the workpiece feed if one or more of them are driven. In the exemplary embodiment, the axes of these needle wheels 32 are arranged at right angles to the feed of the workpiece 2 to be perforated and they are also distributed over the circumference of this workpiece 2 so that corresponding rows of perforations can occur.

If the axes of rotation of the needle wheels 32 are arranged somewhat obliquely, perforations lying on helical lines can be produced under certain circumstances.

The above-described method for perforating, which consists primarily in that Madeln enter the same perforations several times in succession so quickly that frictional heat also arises can also be carried out with the aid of a device shown in FIG. 10. In this case, one or more essentially flat needle fields 33 with fixed needles 8 are provided, via which the workpieces 2 to be perforated can be rolled off. It can be clearly seen how in FIG. 10 a workpiece 2 is gradually moved from its right edge to the left, that is to say in the direction of the arrows Pf 5, and in the process rotates according to the arrows Pf 6.

In order to unroll the hollow body 2 to be perforated via this needle field 33, a conveyor belt 34 running obliquely in the direction of advance against the needle field 33 is provided, which on the opposite side of the needle field 33 is frictionally and / or positively on the hollow bodies by means of projections, tips or the like 2 attacks and presses them gradually in the direction of advance as they roll onto the needles 8. A carrier 35 of this conveyor belt 34 can be adjusted according to the double arrows Pf 7 with regard to its total distance from the needle field 33 and also with regard to its inclined position.

In this case, at least one rotating circular knife 36 and / or at least one preferably pivotable knife blade 41, shown in FIG. 10, is provided for the separation of sleeves 15 which can be advanced by means of the conveyor belt 34 acting on their circumference.

In Fig. 10 it can still be seen that the needles 8 can preferably be cooled with a gastorm or liquid coolant through bores 37 of their carrier 38.

The conveyor belt 34, which is designed as a friction belt, can be pressed against the needle field 33 by means of a pressure plate 39, in order to ensure the desired unrolling of the workpieces despite the resistance in the perforating and / or cutting process.

In particular for changing the inclined position of the conveyor belt, it can be pivotably mounted on an axis 40 running on one side about an axis 40 parallel to the needle plane. It can be seen that the carrier 35 also carries the knife 36.

Overall, this results in a fully automatic and spindle-free device for producing small pipe sections and in particular perforated sleeves. The entire process can be carried out economically and quickly, and it is avoided that perforation residues occur during perforation, which could seriously disrupt the subsequent processes in which the perforated sleeves are required. Such residues could e.g. B. occur if the perforations were punched out. Such stamped parts are avoided by the heated needles. At the same time, by avoiding spindles that hold the workpieces, there is a simple workpiece alignment, which permits correspondingly precise machining, be it when perforating or when separating. In addition, a spindle-free design is particularly quick and economical when loading.

Special heating for the perforating needles and the associated energy expenditure are avoided.

Claims (39)

1. A method of perforating or of perforating and cutting the walls of hollow bodies made of plastic, said bodies being capable of running true or of presenting rotational symmetry, in particular reels such as textile tubes, characterized in that the hollow body (2) to be perforated is rotated and the points where it is to be perforated are repeatedly punctured by a plurality of needles (8) and the puncture action is repeated in succession at a frequency and with a rapidity such that the tips of the needles (8) in each case repeatedly entering holes being formed heat themselves by friction and make perforations from initially small holes.

2. The method as claimed in claim 1, characterized in that a likewise rotating rotary body (9) bearing needles (8) is set into counter- rotation relative to the rotated hollow body (2), the peripheral circle circumscribing the needle tips entering into the surface of the hollow body (2) to be perforated and the speed being selected in such a way that the needle tips repeatedly entering holes are heated by friction.

3. The method as claimed in claim 1 or claim 2, characterized in that the hollow body (2) to be perforated is rotated by the rotation of the needle carrier(s) and the intermittent form-locking of the needles (8) puncturing it.

4. The method as claimed in any one of claims 1 to 3, characterized in that a continuously or intermittently blown hollow body (2) is rotated and is cut off at its later end faces, preferably simultaneously with or subsequent to a perforating operation.

5. The method according to the preamble of claim 1, characterized in that during perforation the hollow body (2) to be perforated is advanced axially and the points where it is to be perforated are repeatedly punctured by needles (8) and the puncture action is repeated in succession at a frequency and with a rapidity such that the tips of the needles (8) repeatedly entering the holes being formed heat themselves and make perforations from initially small holes.

6. The method as claimed in claim 5, characterized in that rotating rotary bodies (9) bearing needles (8) are set into rotation in the direction of motion of the hollow body (2) about axes of rotation disposed transversely to the direction of motion of the hollow body (2), the peripheral circle in each case circumscribing tips of the needles (8) entering the surface of the hollow body (2) to be perforated and the speed being selected in such a way that the tips of the needles (8) repeatedly entering holes are heated by friction.

7. The method according to the preamble of claim 1, characterized in that during perforation the hollow body (2) to be perforated is rolled over a stationary array of needles (8) so that the points where it is to be perforated are repeatedly punctured by needles (8), and that through the rolling speed the puncture action is repeated in succession at a frequency and with a rapidity such that the tips of the needles (8) repeatedly entering holes being formed heat themselves by friction and produce the perforations.

8. The method as claimed in claim 7, characterized in that the hollow bodies (2) are gradually urged deeper onto the needles (8) as they are rolled.

9. The method as claimed in any one of claims 1 to 8, charactierzed in that the self-heating needles (8) are blown and/or pretreated, in particular wetted with a coolant, to regulate their temperature.

10. The method as claimed in claim 9, characterized in that the liquid coolant is applied by atomization or as a drip-feed, in particular brushed on.

11. An apparatus including a device for holding and rotating a hollow body (2) and further including a rotary body (9) as tool carrier, exclusively for performing the method as claimed in any one of claims 1 to 4, 9 or 10, characterized in that the axis of rotation of the tool carrier (9) extends parallel to that of the hollow body (2), the tools taking the form of needles (8) and consequently the tool carrier taking the form of a needle carrier (9) and the length of the needles (8) being selected such that they can penetrate the hollow body (2).

12. The apparatus as claimed in claim 11, characterized in that rotatable supporting cylinders (10) engaging the outer periphery of the hollow body (2) are provided as the means for holding the latter.

13. The apparatus as claimed in claim 11 or claim 12, characterized in that the rotatable needle carrier(s) (9) is/are swivel-mounted relative to the hollow body (2).

14. The apparatus as claimed in any one of claims 11 to 13, characterized in that the cross section of the needles (8) is profiled.

15. The apparatus as claimed in any one of claims 11 to 14, characterized in that the supporting cylinders (10) and/or the needle carrier(s) (9) are adaptable to the diameter of the hollow body (2) to be perforated and that the needle carrier(s) is/are radially adjustable against the inside of the hollow body (2) during finishing.

16. The apparatus as claimed in any one of claims 11 to 15, characterized in that the needle carrier (9) takes the form of a needle cylinder of preferably at least that length which corresponds to the length of the region to be perforated of the hollow body (2), possibly that of the whole hollow body.

17. The apparatus as claimed in particular in any one of claims 11 to 16, characterized in that at least one knife blade or a cutting tool (14) for cutting a tube of predetermined length off an unworked member is disposed in at least one clearance between the supporting cylinders (10) disposed at the periphery for the rotating hollow body (2).

18. The apparatus as claimed in claim 17, characterized in that a plurality of knives are provided in spaced relationship to one another for cutting individual tubes off longer ones or off unworked members and that rings, which are disposed in spaced relationship to one another and are set with needles (8) are also provided for the rotary drive of the hollow bodies (2).

19. The apparatus as claimed in particular in any one of claims 11 to 18, characterized in that a plurality of needle rings and/or needle cylinders (9) are provided for the rotary drive and the perforation, particularly for larger hollow bodies (2).

20. The apparatus as claimed in any one of claims 1 to 19, characterized in that at least one of the supporting cylinders (10) is connected to a drive.

21. The apparatus as claimed in any one of claims 11 to 20, characterized in that a duct for blowing air with outlets (20) directed towards the needles (8) and/or for supplying a liquid coolant is provided next to the needle cylinder (9) or the like, preferably axially parallel thereto.

22. The apparatus as claimed in claim 21, characterized in that at least one brush (21), which acts with its bristles (22) at least in the region of the needle tips, is provided for applying a liquid coolant to the needles (8).

23. The apparatus as claimed in any one of more of claims 11 to 22, characterized in that at least one ejector (23) is disposed opposite where the needle cylinders (9) and/or knives (14) act on the hollow body (2).

24. The apparatus as claimed in claim 23, characterized in that the ejector (23) is connected to the swivel bearing of the needle cylinder (9) or the like and when the needle cylinder (9) is swivelled away from the finished hollow body (2) lifts the latter out between the supporting cylinders (10) in synchronism with said swivelling motion.

25. The apparatus as claimed in any one of claims 11 to 24, characterized in that the knife or knives (14) together with their faces (26) are oriented at an angle, preferably at an acute angle, to the surface of the hollow body (2) and during cutting are preferably advanced deeper into the hollow body and after cutting through it are retractable during the rotary motion.

26. The apparatus as claimed in any one of claims 11 to 25, characterized in that for cutting off short tubes (15) or in particular ring-shaped hollow bodies (2) with knife blades (14) in close juxtaposition, the latter are vertically staggered and when piercing the surface of the hollow body they engage the hollow body (2) at intervals of time.

27. The apparatus as claimed in any one of claims 11 to 26, characterized in that for perforating hollow bodies (2) having a profiled surface, the supporting cylinders (10) have an analogous counter-profile.

28. The apparatus as claimed in any one of claims 11 to 27, characterized in that the supporting cylinders (10) have zones (28, 29) featuring groups of counter-profiles of more prominent contours and such featuring groups of less prominent contours for hollow bodies (2) having profiles (27) arranged in a ring-shape.

29. The apparatus as claimed in any one of claims 11 to 28, characterized in that the ejector (23) takes the form of a straightedge or a similar bar which is mounted parallel to the hollow body (2), has an elastic narrow side (24) acting upon the hollow body (2) and extends over at least part of the length of the hollow body (2).

30. The apparatus as claimed in any one of claims 11 to 29, characterized in that the ejector (23) has on its working edge (24) an elastic lip (25) preferably featuring a loop-shaped cross section for adaptation to movements of the hollow body (2) during ejection.

31. The apparatus as claimed in any one of claims 11 to 30, characterized in that the elastic end of the ejector is made to be springy for promoting the ejecting operation.

32. The apparatus including a device for driving the workpiece and further including a tool carrier (32) exclusively for performing the method according to any one of claims 5, 6, 9 or 16, characterized in that for perforating hollow bodies (2), preferably hollow bodies (2) directly leaving an extruding device, a plurality of needle wheels (32) are provided as tool carriers disposed one behind the other and preferably in angular relationship to one another, the axis of rotation thereof being disposed transversely to the direction in which the hollow body (2) is fed.

33. The apparatus as claimed in any one of claims 11 to 32, characterized in that the axes of the needle wheels (32) are disposed at right angles to the feed of the hollow body (2) to be perforated and that said needle wheels (32) are distributed at the periphery of a hollow body (2) of any cross sectional shape.

34. The apparatus including a device for driving the workpiece (2) and further including a tool carrier (38) exclusively for performing the method according to any one of claims 7 to 9, characterized in that for perforating hollow bodies (2) presenting rotational symmetry there are stationary arrays (33) of needles which are located at the tool carrier (38) and in particular lie in a plane, over which arrays the hollow bodies (2) to be perforated can be rolled.

35. The apparatus as claimed in claim 34, characterized in that a conveyor belt (34) or friction belt preferably running at an angle towards an array (33) of needles in the direction of feed is provided for rolling the hollow bodies (2) to be perforated over said array (33), the hollow bodies (2) being engaged by said belt on the side opposite the array (33) of needles, in particular in a friction-locking manner and/or in a form-locking manner by means of projections, peaks or the like and as they roll being urged deeper onto the needles (8) in the direction of feed.

36. The apparatus as claimed in any one of claims 11 to 35, characterized in that at least one rotating circular knife (26) and/or at least one preferably swivelling knife blade is provided for cutting off tubes (15) which are adapted to be advanced by a conveyor belt (34) engaging their periphery.

37. The apparatus as claimed in any one of claims 11 to 36, characterized in that the needles (8) are capable of being cooled by a gaseous or liquid coolant, preferably through bores in their carrier.

38. The apparatus as claimed in any one of claims 1 to 37, characterized in that the conveyor belt (34) in the form of a friction belt is adapted to be pressed against the array (33) of needles by means of a pressure plate.

39. The apparatus as claimed in any one of claims 11 to 38, characterized in that one side of the friction belt (34) is swivel-mounted about an axis extending parallel to the needle plane.

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