DE102021116796A1 - Pipe clamping device for laser processing system - Google Patents

Abstract

A clamping device (19) for clamping tubular or rod-shaped workpieces in a laser processing system is provided, the clamping device comprising: An annular base body mounted about a central axis of rotation, which at least partially accommodates a clamping jaw drive device and on its front side facing a processing area at least two has groove-shaped recesses which extend in the radial direction, preferably from an inside to an outside of the annular base body; Two sealing elements per groove-shaped recess, a first of the sealing elements being attached to an inner radial end of one of the groove-shaped recesses and a second of the sealing elements being attached to an outer radial end of that groove-shaped recess; At least two, preferably bar-shaped, clamping jaw holders, which can be accommodated in the at least two groove-shaped recesses and can be moved radially by means of the clamping jaw drive device, with the clamping jaw holders in each radial position at the inner radial end and at the outer radial end of the groove-shaped recesses with the corresponding sealing elements stay in contact; and at least two clamping jaws, which can be fastened on the at least two clamping jaw holders at the front side of the base body. A laser processing system comprising the clamping device is also provided.

Description

field of invention

The present invention relates to the field of laser processing systems. In particular, the invention relates to a clamping device for tubular or rod-shaped workpieces in a laser processing system, in particular a laser cutting system.

State of the art

Laser processing systems for processing tubular or bar-shaped workpieces are known in the prior art. Generic systems are for example in the JP 2010-201465 A or JP 2005-152947.

To process the tubular or bar-shaped workpieces, they are clamped in a rotatably mounted clamping device. By means of the clamping device, the workpieces to be processed can be rotated about their longitudinal axis during processing by a laser beam and, if necessary, also moved in the longitudinal direction.

A workpiece is clamped to the clamping device using at least two clamping jaws, which grip and fix the workpiece from the inside (hollow profile) or from the outside. For this purpose, the clamping jaws are each arranged at the same radial distance around an axis of rotation of the clamping device and can be moved synchronously in the radial direction by means of a drive mechanism, which comprises a spiral, for example. The clamping jaws each have a toothed back that engages in the spiral. By rotating the spiral, the clamping jaws are moved radially either inwards or outwards.

A disadvantage of conventional tensioning devices is that the drive mechanism is not sufficiently sealed. Depending on the radial positioning of the clamping jaws on the clamping device, parts of the drive mechanism are exposed during processing of the clamped workpiece and are accessible through processing dust. the 2a and 2 B show an example of an annular clamping device according to the prior art. The clamping jaws are moved inwards here, so that the toothed rear side of the clamping jaws protrudes on the inside of the clamping device and the spiral is exposed in the radially outer areas of the clamping device. With large diameters (e.g. up to 370 mm) of the workpieces to be clamped, the clamping jaws move far outwards so that the toothed back of the clamping jaws protrudes over the outer circumference of the clamping device and the spiral spiral is exposed on the inside of the clamping device. Even when changing the clamping jaws on the clamping device, dirt can be transported from the clamping jaws into the drive mechanism.

Contamination of the drive mechanism is even worse if the suction of the machining dust when machining a tubular workpiece takes place through the workpiece and the ring-shaped clamping device.

The abrasive processing dust, e.g. iron oxide or aluminum oxide (corundum) can lead to early failure of the clamping device.

The object of the invention is to improve the prior art. In particular, a tensioning device is to be provided in which the drive mechanism is better protected against contamination.

The invention

In order to achieve the object on which the invention is based, a clamping device for clamping tubular or bar-shaped workpieces in a laser processing system is provided according to a first aspect. With tubular or bar-shaped workpieces are meant here workpieces that have a much greater length compared to their cross section. Pipe or bar-shaped workpieces can include solid profiles or hollow profiles (e.g. with a round or polygonal closed or open profile).

The clamping device comprises an annular base body mounted about a central axis of rotation, which at least partially accommodates a clamping jaw drive device and which has at least two groove-shaped recesses on its front side facing a processing area of the laser processing system, which extend in the radial direction, preferably from an inside to an outside of the annular body, extend. In connection with the present invention, the wording “annular” is to be understood in such a way that it also includes polygonal profiles which have an opening in the middle. The clamping jaw drive device can comprise a plurality of drive elements, at least some of which are arranged within the main body of the clamping device.

The tensioning device comprises two sealing elements per groove-shaped recess, with a first of the sealing elements on an inner radial end of one of the groove-shaped recesses and a second of the sealing elements is attached to an outer radial end of this groove-shaped recess.

The clamping device also comprises at least two, preferably bar-shaped, clamping jaw holders, which can be accommodated in the at least two groove-shaped recesses and can be moved radially by means of the clamping jaw drive device. The clamping jaw holders are in contact with the corresponding sealing elements in each radial position at the inner radial end and at the outer radial end of the groove-shaped recesses. In other words, the scope for movement of the clamping jaw holders in the radial direction is limited in such a way that they seal the respective groove-shaped recess both on the inside and on the outside during operation. The jaw holders may preferably be shaped to conceal access to the jaw drive means at the front of the clamp.

The clamping device also comprises at least two clamping jaws, which can be fastened on the at least two clamping jaw holders on the front side of the base body.

The clamping jaw drive device can be efficiently protected from contamination by an inventive arrangement of the clamping jaw holders in the groove-shaped recesses and the sealing at the radial ends of the groove-shaped recesses. Compared to conventional clamping devices in which the clamping jaws are received directly in corresponding guide rails, another advantage of the present invention is that the groove-shaped recesses are not exposed when changing the clamping jaws, but remain covered by the clamping jaw holder.

According to a preferred variant, the clamping jaw drive device can comprise a spiral which is arranged in particular within the main body of the clamping device. In this case, each of the clamping jaw holders can have a toothed area on its side facing the base body, which can be brought into engagement with the flat spiral in order to be movable in the radial direction by rotating the flat spiral. The toothed area only extends in a middle section over the length of each clamping jaw holder. Between the toothed area and the respective longitudinal end of a clamping jaw holder, the clamping jaw holders do not have any teeth on their respective rear side. The non-toothed areas on the back of each jaw holder extend over a length that corresponds at least to the length of the maximum travel of the jaw holder in the radial direction. It goes without saying that the toothing on each of the clamping jaw holders is adapted according to its position in the circumferential direction on the spiral so that the clamping jaw holders are arranged radially at the same distance around the central axis of rotation of the clamping device.

The at least two clamping jaw holders can each have a substantially cross-shaped or “+”-shaped cross section. It goes without saying that in this case the groove-shaped recesses have a corresponding, likewise essentially cross-shaped or “+”-shaped cross section. A defined guidance of the clamping jaw holders in the groove-shaped recesses can be ensured by such a configuration. Furthermore, the access of machining dust to the gaps between the clamping jaw holder and the groove-shaped recess is made more difficult.

In the case of the clamping device, the at least two groove-shaped recesses can be distributed uniformly over the circumference of the base body.

According to a preferred variant, the base body can have at least three, preferably four, groove-shaped recesses and a number of clamping jaw holders that corresponds to the number of groove-shaped recesses.

Each of the sealing elements can have a preferably metallic frame and a sealing layer made of an elastic material, for example acrylonitrile butadiene rubber or nitrile butadiene rubber (NBR), with the sealing layer being designed to be connected to a respective clamping jaw holder in to get in touch. A sealing element according to the present invention can have a layered structure, with the sealing layer being fixed between two frame layers. According to a further variant, each sealing element can also have an intermediate layer, in particular a metallic one, which is arranged between the sealing layer and the outer (first) frame layer. This intermediate layer is used to collect and remove coarse dirt deposits on the clamping jaw holders when the clamping jaw holders are moved radially. It is understood that the sealing layer protrudes a small amount towards the interior of the sealing element beyond the intermediate layer. Only in this way can an adequate seal be guaranteed by the sealing layer.

To solve the problem on which the invention is based, according to a second aspect, a laser processing system for processing tubular or rod-shaped workpieces provided. The laser processing system can preferably be a laser cutting system. The laser processing system includes a processing area with a laser processing unit for processing the tubular or rod-shaped workpiece, and one or more support devices for supporting the tubular or rod-shaped workpiece during processing by the laser processing unit. Furthermore, the laser processing system comprises a clamping device according to one of the variants described above, the clamping device being designed to clamp the workpiece to be processed and to rotate it about its longitudinal axis during processing by the laser processing unit.

The laser processing system can be designed as a laser flatbed machine (cf. 1 ) or as a special tube processing machine, such as in connection with the DE 20 2020 101 342 U1 described.

The laser processing system can also include a suction device which is connected to the rear of the ring-shaped base body of the clamping device and which is designed to, when processing a tubular workpiece, processing residues that occur during processing of the tubular workpiece, through the tubular workpiece and through the ring-shaped base body of the clamping device. The principle of such a suction device is, for example, in DE 20 2020 101 342 U1 described.

character list

The following description of preferred exemplary embodiments serves to explain the invention in more detail in conjunction with the drawings.

• 1 eine perspektivische Ansicht einer Laserbearbeitungsanlage;
• 2a eine perspektivisch vergrößerte Ansicht der Einspannung eines rohrförmigen Werkstücks in der Spannvorrichtung einer Laserbearbeitungsanlage gemäß 1;
• 2b-c Beispiel einer Spannvorrichtung gemäß dem Stand der Technik aus verschiedenen Perspektiven;
• 3a-c Ansichten einer erfindungsgemäßen Spannvorrichtung ohne montierte Spannbacken;
• 4 eine perspektivische Schnittdarstellung einer erfindungsgemäßen Spannvorrichtung entlang der Schnittebene A-A in 3c;
• 5 ein Dichtungselement gemäß der vorliegenden Erfindung;
• 6 eine Spannbacke gemäß er vorliegenden Erfindung und deren Befestigung an einem Spannbackenhalter; und
• 7a-e Varianten einer erfindungsgemäßen Spannvorrichtung mit unterschiedlichen Spannbacken.

Show it:

• 1 a perspective view of a laser processing system;
• 2a a perspective enlarged view of the clamping of a tubular workpiece in the clamping device of a laser processing system according to 1 ;
• 2b-c Example of a clamping device according to the prior art from different perspectives;
• 3a-c Views of a clamping device according to the invention without mounted clamping jaws;
• 4 a perspective sectional view of a clamping device according to the invention along the section plane AA in 3c ;
• 5 a sealing element according to the present invention;
• 6 a jaw according to the present invention and its attachment to a jaw holder; and
• 7a-e Variants of a clamping device according to the invention with different clamping jaws.

In 1 a perspective view of a laser processing system 11 is shown. This exemplary laser processing system 11 has the form of a laser flat bed machine for the selective processing of plate-shaped or tube-shaped or bar-shaped workpieces 12 . The laser processing system 11 includes a housing 14 in which a processing area 15 is provided. A laser processing unit (not shown) with a laser processing head can be moved within processing area 15, for example to process a plate-shaped workpiece (not shown) lying on a workpiece support 16 or to process a tubular or rod-shaped workpiece 12 picked up by a handling device 18. In the 1 The laser processing system 11 shown is prepared for the processing of a tubular or rod-shaped or profile-shaped elongate workpiece 12 . The workpiece support 16 can be taken out of the processing area 15 by a displacement device 17, in particular a mobile carriage, and moved into a loading and unloading area arranged adjacent thereto, preferably outside of the processing area 15, as is shown in 1 is shown.

The handling device 18 of the laser processing machine 11 comprises a rotatable clamping device (or a chuck) 19 and one or more support devices 21, which are used to support the tubular or rod-shaped workpiece 12 during processing. The rotatable clamping device 19 defines a central axis of rotation 19x (see Fig. 3a-c ) around which the workpiece 12 can be rotated during processing. This axis of rotation 19x extends in the X direction.

The support devices 21 are aligned in such a way that the central axis of the tubular or rod-shaped workpiece 12 coincides with the axis of rotation 19x of the clamping device 19 .

In the housing 14 of the laser processing machine 11, a guide rail 23 runs in the X direction, on which the support devices 21 are slidably arranged. A support device 21 preferably has a guide body 24 which is movably arranged on the guide rail 23 . A chain drive 26 preferably extends parallel to the guide rail 23 and can be used to displace one or more support devices 21 along the guide rail 23 .

This chain drive 26 can control a displacement movement of the support devices 21 depending on the size or the length of the workpiece 12 to be machined.

2 shows a perspective enlarged view of the laser processing system according to FIG 1 . In 2 It can be seen how a tubular workpiece 12 to be machined is clamped in the clamping device 19 and rotatably mounted in the support device.

In connection with the 3 until 7 Aspects of a clamping device 19 according to the invention are explained in more detail below.

the 3a-c show a clamping device 19 according to the invention in perspective from the front ( 3a) , from behind ( 3b) and in a front view ( 3c ). 4 shows a sectional view along the section plane AA in 3c . the 3a-c and 4 show the clamping device 19 without mounted clamping jaws. Inventive clamping devices with mounted jaws are in the 7a-e shown and described below.

The clamping device 19 has an annular base body 190 which defines a central axis of rotation 19x around which the clamping device 19 is rotatably mounted. A clamping jaw drive device 195 or parts of a clamping jaw drive device 195 are arranged in the base body 190 . In the example shown, the clamping jaw drive device 195 includes a plan spiral 1952, which extends inside the base body 190 over its entire circumference.

On its front side 191, the base body 190 has at least two groove-shaped recesses 196, in each of which a clamping jaw holder 198 is accommodated. The recesses 196 are shown in the illustrations only in the sectional view according to FIG 4 indicated by way of example, since they are covered or filled in by the clamping jaw holder 198 inserted therein. At its rear, each of the jaw holders 198 has a toothed portion 1982 which engages one or more helically extending ribs on the front of the plano spiral 1952 . By rotating the spiral 1952, which can be done by a gear drive on the back of the spiral 1952, the clamping jaw holder 198 can be moved synchronously in the radial direction in this way.

Two sealing elements 197 are arranged on each of the groove-shaped recesses 196, with a first of the sealing elements 197-1 being attached to an inner radial end of one of the groove-shaped recesses 196 and a second of the sealing elements 197-2 being attached to an outer radial end of this groove-shaped recess 196 .

The clamping device 19 is designed in such a way that the clamping jaw holders 198 are in contact with the corresponding sealing elements 197-1, 197-2 at the inner radial end and at the outer radial end of the groove-shaped recesses 196 in each radial position. This prevents processing dust, for example cutting dust, from penetrating the inside or outside of the base body 190 via the groove-shaped recesses 196 into the interior of the base body and soiling and permanently damaging the clamping jaw drive device.

The travel of the jaw holders 198 within the grooves 196 may be physically limited by the location of the serrated area 1982 on the rear of each of the jaw holders 198, for example. The toothed area 1982 protrudes on the rear side of the jaw holders 198 and cannot be moved through the sealing elements 197-1, 197-2, which rest flat against the non-toothed surfaces of the jaw holders 198 (cf. 4 ). A clamping jaw holder 198 can therefore also only be removed from its groove-shaped recess 196 if at least one of the sealing elements 197 - 1 , 197 - 2 has been detached from one of the ends of the recess 196 .

A detailed view of a sealing element 197 according to the present invention is shown in FIG 5 shown. The sealing element 197 can be used both as a first sealing element 197-1 at the radially inner end of a groove-shaped recess and as a second sealing element 197-2 at the radially outer end of a groove-shaped recess. Each sealing element 197 has a frame with a frame layer 1972 and a sealing layer 1976 . The frame with the frame layer 1972 is preferably made of metal, while the sealing layer 1976 is made of an elastic material, for example an acrylonitrile butadiene rubber or nitrile butadiene rubber (NBR), a polyamide (PA), a polytetrafluoroethylene (PTFE) or a other suitable plastic. In the illustrated embodiment In addition, the sealing element 197 has an intermediate layer 1974 which is thinner than the sealing layer 1976 and which is arranged between the sealing layer 1976 and the frame layer 1972. The intermediate layer 1974 is preferably constructed of a relatively rigid material, preferably metal.

The sealing elements 197 each have a C-shape with an inner contour which corresponds to an outer contour of the clamping jaw holders 198 (in their non-toothed sections). The sealing layer 1976 protrudes at the inner contour of the sealing elements 197 by a small amount (e.g. 0.1 mm - 1 mm) so that it is pressed against the outer surfaces of a jaw holder 198 in use. The intermediate layer 1974 protrudes at the inner contour from the frame layer 1972 but lags behind the sealing layer 1976. The intermediate layer 1974 performs a wiping function to remove coarse dirt from the surface of a clamping jaw holder 198 when this is moved radially in a groove-shaped recess 196.

Each sealing element 197 is fastened to a respective groove-shaped recess 196 radially on the inside or radially on the outside by means of suitable fastening elements 1978, e.g. screws.

6 12 is an illustration of a jaw 199 for mounting on a jaw holder 198 of a clamping device 19 according to the present invention. The clamping jaw 199 is preferably positioned on the corresponding clamping jaw holder 198 by means of a tongue and groove connection. For defined positioning in the radial direction, each clamping jaw holder 198 can have a plurality of recesses in which a spring of the clamping jaw 199 to be fastened can be accommodated. For defined positioning in the circumferential direction, each clamping jaw holder 198 can in turn have a spring running in the radial direction, which engages in a groove on the back of the clamping jaw 199 . The jaw holders 198 are preferably configured such that a jaw 199 can be mounted thereon in various radial positions. In this way, the comparatively small radial displacement path of the clamping jaw holders 198 compared to conventional clamping devices can be compensated. The clamping jaws 199 are preferably fastened to the clamping jaw holders 198 by means of a suitable screw connection.

7a until 7e show different variants of clamping devices 19a to 19e according to the invention, which differ in the use of different clamping jaws 199a to 199e.

7a shows an example of connection sockets 1954 of the clamping jaw drive device 195. In order to move the clamping jaws radially, a drive train connected to an external motor engages with an adapter in one of the connection sockets 1954 in order to turn a gear wheel which engages with the face plate 1952 and rotates it offset rotation.

By means of in the 7a and 7b If the clamping jaws used are used, tubular workpieces can be clamped from the inside by putting one end of the tube over the clamping jaws 199 and moving the clamping jaws 199 radially outwards and pressing them against the inner wall of the tube. With the clamping jaws 199a according to 7a small-diameter tubular or bar-shaped workpieces can also be clamped from the outside. In the 7b The clamping jaws 199b used, which each have a step shape, can also be mounted the other way around, so that the highest step is located radially on the outside. In this way, pipes can also be clamped from the outside by means of the illustrated clamping jaws 199b.

the 7c and 7d show variants of clamping devices 19c and 19d for clamping angular, in particular rectangular, hollow profiles, ie rod-shaped workpieces with a rectangular hollow profile. The profile is fixed at two opposite corners either from the inside by means of a clamping device 7c or from the outside by means of a clamping device according to 7d clamped. It should be mentioned that in practice, depending on the internal dimensions of the workpiece to be clamped, only one pair of rollers of the clamping jaws 199c according to 7c is mounted.

7e shows a clamping jaw design that is designed to machine the workpiece clamped on it up to close to the clamped end. A collision with the base body 190 of the clamping device 19e can be prevented by the clamping jaws 199e, which are extended in the X direction.

As in the 7c until 7e As can be seen, the jaw holders 198 which are not occupied by jaws 199 remain mounted even if only two jaws 199 are used. In this way, all groove-shaped recesses remain covered during the machining of the clamped workpiece and are inaccessible to machining dirt.

Reference List

11

laser processing facility

12

Tubular workpiece

14

enclosure

15

editing area

16

workpiece support

17

shifting device

18

handling device

19

clamping device

19a-e

Clamping devices with different clamping jaws

19x

Central axis of rotation

190

Main body of the clamping device

191

front of the body

192

inside of the main body

193

outside of the body

194

back of the body

195

Jaw drive device

1952

plan spiral

1954

Connection socket of the clamping jaw drive device

196

Grooved recess

197

sealing element

197-1

First sealing element

197-2

Second sealing element

1972

frame layer

1974

intermediate layer

1976

sealing layer

1978

fastener

198

jaw holder

1982

serrated area

199

clamping jaw

199a-e

Various clamping jaw types

21

support device

23

guide rail

24

guide body

26

chain drive

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• JP 2010201465 A [0002]
• DE 202020101342 U1 [0021, 0022]

Claims (8)

Clamping device (19) for clamping tubular or bar-shaped workpieces in a laser processing system, the clamping device comprising: An annular base body (190) mounted about a central axis of rotation (19x), which at least partially accommodates a clamping jaw drive device (195) and which has at least two groove-shaped recesses (196) on its front side (191) facing a processing area (15). extend in the radial direction, preferably from an inside (192) to an outside (193) of the annular base body (190); Two sealing elements (197) per groove-shaped recess (196), with a first of the sealing elements (197-1) at an inner radial end of one of the groove-shaped recesses (196) and a second of the sealing elements (197-2) at an outer radial end this groove-shaped recess (196) is attached; At least two, preferably bar-shaped, clamping jaw holders (198) which can be accommodated in the at least two groove-shaped recesses (196) and can be moved radially by means of the clamping jaw drive device (195), the clamping jaw holders (198) being at the inner radial end in each radial position and at the outer radial end of the groove-shaped recesses (196) are in contact with the corresponding sealing elements (197-1, 197-2); and At least two clamping jaws (199) which can be fastened to the at least two clamping jaw holders (198) on the front side (191) of the base body (190). Clamping device (19) after claim 1 , wherein the clamping jaw drive device (195) comprises a spiral (1952) and wherein each of the clamping jaw holders (198) has a toothed area (1982) on its side facing the base body (190), which can be brought into engagement with the spiral (1952). is to be moved in the radial direction by rotating the plan spiral (1952). Clamping device (19) according to one of the preceding claims, wherein the at least two jaw holders (198) each have a substantially cross-shaped cross-section. Clamping device (19) according to one of the preceding claims, wherein the at least two grooves (196) are distributed uniformly over the circumference of the base body (190). Clamping device (19) according to one of the preceding claims, wherein the base body (190) has at least three, preferably four, groove-shaped recesses (196) and wherein the clamping device (19) has a number of clamping jaw holders ( 198). Clamping device (19) according to one of the preceding claims, wherein each of the sealing elements (197) has a, preferably metallic, frame and a sealing layer (1976) made of an elastic material, the sealing layer (1976) being designed for this purpose, with a respective clamping jaw holder (198) to get in touch. Laser processing system (11) for processing tubular or rod-shaped workpieces (12), comprising: a processing area (15) with a laser processing unit for processing the tubular or rod-shaped workpiece (12); One or more support devices (21) for supporting the tubular or rod-shaped workpiece (12) during processing by the laser processing unit; and A clamping device (19) according to any one of Claims 1 until 6 , wherein the clamping device (19) is designed to clamp the workpiece (12) to be processed and to rotate it about its longitudinal axis during processing by the laser processing unit. Laser processing system (11) according to claim 7 further comprising: A suction device which is connected to the rear side (194) of the annular base body (190) of the clamping device (19) and which is designed to remove, when machining a tubular workpiece (12), machining residues which are produced when machining the tubular workpiece (12) accrue, through the tubular workpiece (12) and through the annular base body (190) of the clamping device (19).

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