Chuck

Abstract

A winding machine chuck for receiving and fixing a winding tube (32). The winding tube (32) is held on the circumferential surface of a clamping bush (1) via a clamping device (5), which is unclamped via a compressed air supply. The compressed air is supplied via an annular chamber (14) formed between the clamping bush (1) and the shaft carrier (2). The annular chamber (14) can be vented at the open end (19) of the clamping bush (1) via a circumferential wall opening (18) formed between the shaft carrier (2) and the clamping bush (1). The circumferential wall opening (18) can be repeatedly closed via a sealing means (21). In this case, the sealing means (21) is formed, according to the invention, by an elastic cavity seal (22), which can be expanded by compressed air.

Description

[Technical field]

[0001] The present invention relates to a winding machine chuck for receiving and fixing a winding tube for winding a yarn to form a package according to the preamble of claim 1 . [Background technology]

[0002] The initially mentioned chuck of a winding machine is known, for example, from DE 196 07 916 A1.

[0003] Such a chuck is preferably used in a winding machine for winding freshly spun synthetic yarns to form a package. For this purpose, several winding tubes are fitted one after the other onto the chuck, which is arranged so as to protrude into the winding machine. To clamp the winding tubes, the chuck has a clamping device. This clamping device has several clamping elements which can be guided radially outwards. The clamping device is integrated into a clamping bush, which is held on a shaft carrier, which protrudes into the clamping bush. Furthermore, the clamping bush is driven and held at a distance from the shaft carrier, so that a circumferentially extending annular chamber is formed between the shaft carrier and the clamping bush. The clamping device formed on the clamping bush has several clamping elements. For clamping and unclamping, the clamping elements are respectively arranged between a spring and a pressure chamber. The pressure chambers can be connected together via an annular chamber to a compressed air source. At the open end of the clamping bush, a circumferential opening is formed between the collar of the shaft carrier and the end face end of the clamping bush, which is connected to an annular chamber in the interior of the chuck and can be selectively closed by a sealing means, for which purpose a sealing piston is guided in a sliding manner in the shaft carrier as the sealing means, so that it can press against the sealing surface of the end face of the clamping bush with a seal.

[0004] In order to clamp the tube and to wind the yarn during operation, the clamping device is operated without pressure, so that the clamping elements are held in a radially outer position under the action of a spring and fix the tube which is pushed over the periphery of the clamping bush. In this situation, the periphery openings at the end faces of the clamping bush are open and the annular chamber between the clamping bush and the shaft carrier is connected to the periphery in order to vent all pressure chambers.

[0005] After the package has been wound to the end on the winding tube and the clamping bush has been braked to change the package, the compressed air supply is activated, the sealing piston first closes the circumferential wall opening between the shaft carrier and the clamping bush, so that the compressed air flowing into the annular chamber between the shaft carrier and the clamping bush can be guided into the pressure chamber of the clamping device. In the clamping element, a pneumatic force against the spring is generated, which causes the clamping element to adjust, so that it releases the winding tube around the clamping bush. This process is repeated with each package change.

[0006] In order to move the sealing piston of the shaft carrier to close the circumferential opening, compressed air is introduced into the annular chamber of the sealing piston. In this respect, the sealing piston has an additional seal, which allows the pressure build-up for moving the sealing piston. The sealing of the circumferential opening at the end face of the clamping bush is therefore essentially dependent on the function of the sealing piston. The return of the sealing piston is therefore brought about via a spring element, which does not return the sealing piston in the event of breakage. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the invention is therefore to develop the chuck mentioned at the outset in such a way that the circumferential opening at the end face of the clamping bush can be closed with high reliability and reproducibility. [Means for solving the problem]

[0008] This object is achieved according to the invention in that the sealing means is formed by an elastic cavity seal, which can be expanded by compressed air.

[0009] Advantageous refinements of the invention are defined by the features and feature combinations recited in the dependent claims.

[0010] The invention has the special advantage that no movable, axially displaceable elements are present in the shaft carrier for sealing the circumferential opening. As sealing means, a fixedly arranged elastic cavity seal is used, which can be expanded by compressed air for sealing. In order to be able to close the comparatively large gap width of the circumferential opening, movable elements are no longer necessary. Furthermore, exact centering of the shaft carrier and the clamping bush is no longer necessary. Due to the elasticity of the cavity seal, even in the expanded state, certain errors in the position of the clamping bush and the position of the shaft carrier can be compensated.

[0011] In order to allow a direct supply of compressed air to the cavity seal if necessary, a refinement of the invention is provided in which the annular cavity seal has a compressed air connection in the bottom area, which compressed air connection cooperates with an inlet hole in the shaft carrier, so that the compressed air supply takes place directly via the inlet hole in the shaft carrier.

[0012] A refinement of the invention is particularly advantageous in that the inlet bore is connected to an air supply passage in the shaft carrier, by which the annular chamber is connected to a compressed air source, in that one common compressed air connection can be used for the compressed air source used to unclamp the clamping element and to inflate the seal, and separate compressed air connections are therefore not required.

[0013] In order to obtain a sealing of the peripheral opening directly inside the clamping bush, a refinement of the invention is provided in which a cavity seal is arranged in a circumferential groove in the peripheral surface of the shaft carrier against the peripheral wall of the clamping bush. Thus, the radially acting sealing of the peripheral opening is realized directly on the peripheral surface of the shaft carrier. Furthermore, the possibility of centering the clamping bush on the shaft carrier is provided when sealing the peripheral opening by the cavity seal.

[0014] Alternatively, however, it is also possible to arrange the cavity seal against the end end of the clamping bush on the end wall of the collar of the shaft carrier, in such a way that the axial sealing of the circumferential opening is achieved.

[0015] Depending on the size of the sealing gap between the shaft carrier and the clamping bush, various types of cavity seals are possible. The first variation of the cavity seal has an expandable sealing profile, which allows sealing gaps of more than 3 mm to be closed. This allows relatively large sealing gaps to be filled.

[0016] Alternatively, however, a variation is also available in which the cavity seal is formed by an expandable seal profile, by means of which a sealing gap of less than 3 mm can be closed. In this variation of the cavity seal, the seal profile is produced essentially exclusively by stretching the contour with compressed air.

[0017] The sealing effect is further improved by a refinement of the invention in which the cavity seal has at least one outer sealing lip in the sealing profile, but preferably several sealing lips are used, so that the smallest possible pressure loss can be achieved when the clamping device is unclamped.

[0018] Exemplary embodiments of the chuck according to the present invention and further advantages of the present invention are explained in more detail below with reference to the accompanying drawings. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic vertical cross-sectional view showing an embodiment of a chuck according to the present invention. [Diagram 2] FIG. 2 is an enlarged schematic view of the embodiment of the sealing means shown in FIG. 1 in an open position; [Diagram 3] FIG. 2 is an enlarged schematic view of the embodiment of the sealing means shown in FIG. 1 in a closed position; [Figure 4] FIG. 11 is an enlarged view showing a schematic view of a sealing means according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] 1 shows a schematic longitudinal section of an embodiment of a chuck according to the invention, as used, for example, in a winding machine for winding a yarn on a number of bobbins. The chuck has a drive shaft 3, which is rotatably supported in a hollow cylindrical shaft carrier 2 by means of bearings 4. At its end, not shown in FIG. 1, the drive shaft 3 is connected to an electric drive. At its end projecting from the shaft carrier 2, the drive shaft 3 is connected non-rotatably to a hollow cylindrical tensioning bush 1 via a hub 15. A projecting piece of the shaft carrier 2 projects into the open end of the tensioning bush 1 to support the drive shaft 3.

[0021] A clamping device 5 is arranged on the circumferential surface of the clamping bush 1. The clamping device 5 has an outer clamping sleeve 7 and a number of clamping elements 6 arranged between the clamping bush 1 and the clamping sleeve 7. In this embodiment, each clamping element 6 is formed by a radially movable clamping piece 10 and an axially movable piston 8, in which the clamping pieces 10 are guided via a wedge-shaped guide surface. The clamping pieces 10 protrude into openings 11 of the outer clamping sleeve 7, and the piston 8 has a number of cutouts 38 distributed on the circumferential surface for receiving the clamping pieces 10.

[0022] A piston 8, which is guided in the axial direction for radially adjusting the clamping piece 10, is arranged between a spring 9 and a pressure chamber 12, which is formed between the clamping sleeve 7 and the clamping bush 1. The piston 8 is supported on a stop 17, which is fixedly connected to the clamping bush 1 via the spring 9. In the situation illustrated in FIG. 1, the clamping element 6 is shown in a clamping position, in which the clamping piece 10 is held in the driven clamping position by the piston 8 with the aid of the spring 9. To release the winding tube 32, a pressure medium, preferably compressed air, is applied to the piston 8 on the side located opposite the spring 9 via the pressure chamber 12, so that the piston 8 moves against the spring 9 in the direction of the stop 17. This causes a wedge-shaped guide surface to move so that the clamping piece 10 can move radially inwards. For sealing against the pressure chamber 12, the piston 8 has a number of seals on the pressure side, which respectively cause a seal between the piston 8 and the clamping bush 1 and between the piston 8 and the clamping sleeve 7.

[0023] The clamping elements 6 adjacent to the clamping bush 1 in the longitudinal direction are of identical design, and the end faces of the pistons 8 to which pressure is applied face each other at a distance and define a pressure chamber 12. The winding tube 32 is thus clamped by two adjacent clamping elements 6. For release, both pistons 8 of adjacent clamping elements 6 are controlled simultaneously by the pressure chamber 12. For this purpose, the pressure chamber 12 is connected via a through-hole 13 in the peripheral wall 31 of the clamping bush to an annular chamber 14 formed between the clamping bush 1 and the shaft carrier 2.

[0024] In the longitudinal direction of the clamping bush 1, the clamping device 5 has a number of clamping elements 6, each of which is identically designed, in which the respective pressure chamber 12 is connected via a through-hole 13 to a pressure chamber 14 or a pressure chamber 35 in front of the clamping bush 1. The annular chamber 14 is connected via a number of passages 33 in the circumferential surface of the shaft carrier 2 to an air supply passage 34 in the shaft carrier 2. The air supply passage 34 can be formed, for example, by holes in the shaft carrier 2. The air supply passage 34 is connected to a controllable compressed air source 39 (FIG. 2).

[0025] At the free end of the chuck, a cover 16 is fixedly held on the clamping bush 1. The cover 16 is dimensioned in such a way that the pressure chamber 35 formed in the clamping bush 1 at its end is closed by the cover 16.

[0026] At the opposite end, the clamping bush 1 has a free end face edge 19 which is embodied in the form of a flange and which forms a sealing surface 20 on its outer side. A peripheral opening 18 is formed between the end face edge 19 of the clamping bush 1 and the shaft carrier 2, which faces the end face edge 19 and has a flange 28. The peripheral opening 18 connects the annular chamber with the periphery for degassing the pressure chamber 12. A sealing means 21 is associated with the peripheral opening 18 at the flange 28 of the shaft carrier 2, by means of which the peripheral opening 18 is held selectively open or closed.

[0027] To further explain the sealing means 21 arranged on the collar 28 of the shaft carrier, reference is further made to Figure 2, which shows an enlarged view of a portion of the peripheral wall opening 18 between the clamping bush 1 and the shaft carrier 2. The following description therefore applies to both figures.

[0028] An annularly extending circumferential groove 25 is formed on an end wall 27 of a flange 28 of the shaft carrier 2. A cavity seal 22 is arranged in this circumferential groove 25. The cavity seal 22 has a compressed air connection 23 at the groove bottom of the circumferential groove 25. The compressed air connection 23 is connected via an inlet hole 26 to an air supply passage 34 inside the shaft carrier 2.

[0029] The cavity seal 22 faces a sealing surface 20 provided on the end face end 19 of the clamping bush 1. In the present embodiment, the cavity seal 22 has an expandable seal profile 24. The seal profile 24 is annular and is expanded by compressed air supplied by a compressed air connection 23.

[0030] In the situation shown in Figures 1 and 2, the cavity seal 22 is shown in its resting state without pressure. In this operating situation, several winding tubes are usually clamped around the chuck in order to wind several yarns in parallel on the winding tube to form a package. In this situation, the peripheral opening 18 between the shaft carrier 2 and the clamping bush 1 is open, so that the pressure chamber 12 is evacuated. The clamping element 6 of the clamping device 5 is held in the clamping position via a spring force.

[0031] At the end of the winding process, the drive shaft 3 is braked together with the clamping bush 1 so that the completely wound package can be removed from the chuck. Compressed air is then supplied from the compressed air source 39 and is introduced via the air supply channel 34. From there it passes through the inlet 26 to the cavity seal 22. The cavity seal 22 is expanded by the compressed air so that the sealing profile 24 unfolds and closes the sealing gap at the peripheral opening 18. In this case, the cavity seal 22 rests against the sealing surface 20 at the end face end 19 of the clamping bush 1. This situation is illustrated in FIG. 3, which shows the part illustrated in FIG. 2 in a merely modified operating situation. In so far as this is concerned, the explanation for FIG. 2 also applies analogously to FIG. 3.

[0032] After the peripheral opening 18 has been closed by the cavity seal 22, a positive pressure is generated in the pressure chamber 12 of the clamping device 5, which moves the piston 8 against the spring 9 and thus the tube 32 is released. The full package is now removed from the chuck and replaced by a new empty tube. As soon as the empty tube has been pushed onto the peripheral surface of the chuck, the compressed air supply is stopped, which relaxes the cavity seal 22 and opens the peripheral opening 18. The annular chamber 14 is connected to the periphery and the pressure chamber 12 is vented. The clamping piece 10 is now held in a tight position by the spring tension.

[0033] It should be explicitly stated here that the construction of the chuck is exemplary. Thus, for example, the shaft carrier 2 can be constructed integrally, i.e. in one piece, or can be constructed from several components. In particular, the collar 28 here can be formed from a separate component. The clamping element 6 shown is likewise exemplary. It is important here that compressed air is required for release, which is supplied via an annular chamber.

[0034] In the above-described embodiment, the radial sealing gap between the end face edge 19 and the opposing cavity seal 22 is sealed in the axial direction at the circumferential wall opening 18. However, it is basically also possible to arrange the cavity seal 22 directly on the circumferential surface of the shaft carrier 2 and use it as a radial seal. In this respect, FIG. 4 shows some possible embodiments of the alternative sealing means in the chuck. The embodiment shown in FIG. 1 is identical in the structure of the chuck to the embodiment shown in FIG. 1, so that for the overall structure of the chuck reference is made to the above description, and only the differences will be described here.

[0035] In FIG. 4, a circumferential groove 25 is arranged on the circumferential surface of the shaft carrier 2 in the clamping bush 1. A cavity seal 22 is held in the circumferential groove 25. The cavity seal 22 has a compressed air connection 23 at the bottom of the circumferential groove 25. The compressed air connection 23 is connected to the air supply passage 34 via an inlet hole 26. An annular cavity seal 22 is arranged in the circumferential groove 25. The cavity seal 22 has an expandable sealing profile 24 with a number of outer sealing lips 29. The sealing lips 29 in the cavity 24 lie against the circumferential wall 31 of the clamping bush 1 with a sealing gap of the circumferential wall opening 18. In the situation shown in FIG. 4, the cavity seal 22 is shown in an unloaded state, such that the circumferential wall opening 18 between the shaft carrier 2 and the clamping bush 1 is open.

[0036] In order to be able to carry out the unclamping of the clamping device 5, when compressed air is supplied, the cavity seal 22 stretches in such a way that the sealing lip 29 seals the sealing gap of the circumferential opening 18 in the circumferential section 31 of the clamping bush 1. In this case, mainly only an expansion of the cavity seal 22 occurs. Such a cavity seal 22 can therefore only fill smaller sealing gaps, preferably <3 mm. In contrast, the embodiment of the hollow seal 22 shown in FIG. 2 is suitable for filling and sealing larger sealing gaps in the range of more than 3 mm.

Claims

1. A chuck for a winding machine for receiving and fixing a winding tube for winding a yarn into a package, the chuck having a protruding shaft carrier (2) and a clamping bush (1) held on the circumferential surface of the shaft carrier (2), the clamping bush (1) having a clamping device (5) for fixing the winding tube (32) on its circumferential surface, the clamping device (5) having a plurality of movable clamping elements (6), the clamping elements (6) being respectively arranged between a pressure chamber (12) and a spring (9), the pressure chamber (12) being arranged between the pressure chamber (12) and a spring (9), the clamping element (5 ... a chuck in which the chamber (12) is connectable to a compressed air source via an annular chamber (14) formed between the shaft carrier (2) and the clamping bush (1), the annular chamber (14) being connected to the periphery at an inner end face end (19) of the clamping bush (1) by a peripheral wall opening (18) formed between the clamping bush (1) and a flange (28) of the shaft carrier (2), the peripheral wall opening (18) being closable by a sealing means (21) arranged between the shaft carrier (2) and the clamping bush (1), A chuck, characterized in that the sealing means (21) is formed by an elastic cavity seal (22), which is expandable by compressed air.

2. 2. The chuck according to claim 1, wherein the cavity seal (22) has a compressed air connection (23) in a bottom region, which cooperates with an inlet hole (26) provided in the shaft carrier (2).

3. 3. The chuck of claim 2, wherein said inlet hole (26) is connected to an air supply passage (34) in said shaft carrier (2) and said annular chamber (14) is connected to said source of compressed air by said air supply passage (34).

4. 4. The chuck according to claim 1, wherein the cavity seal (22) is arranged opposite the end end (19) of the clamping bush (1) on an end wall (27) of a flange (28) of the shaft carrier (2).

5. 5. The chuck according to claim 1, wherein the cavity seal (22) is formed by an expandable seal profile (24) by which a seal gap of a peripheral wall opening (18) larger than 3 mm can be closed.

6. 5. The chuck according to claim 1, wherein the cavity seal is formed by an expandable seal profile (30), by which a seal gap of the peripheral wall opening (18) of less than 3 mm can be closed.

7. 7. The chuck according to claim 1, wherein the cavity seal (22) has at least one outer sealing lip (29) at a seal profile (30).

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