EP0675772A1

EP0675772A1 - Winding drum of a winder for bands with a clamping device for the start of the band

Info

Publication number: EP0675772A1
Application number: EP94903860A
Authority: EP
Inventors: Horst Nickel; Eckhard Betz
Original assignee: Sundwiger Eisenhuette Maschinenfabrik & Co GmbH
Current assignee: Sundwiger Eisenhuette Maschinenfabrik & Co GmbH
Priority date: 1992-12-22
Filing date: 1993-12-21
Publication date: 1995-10-11
Also published as: WO1994014551A1; JPH08507253A; DE4243434A1

Abstract

The invention concerns a winding drum for bands with at least two expandable segments (3, 4) which can be expanded by means of at least one expanding wedge (7) situated between them, and a clamping element (14) which is pivotably mounted at the perimeter of the drum within the circumference and acts with a fixed stop (4a) to clamp the start of the band. To simplify the operation of the clamping element (14) and create a smooth transition in the region of the clamping element (14) for the band being wound, the clamping element (14) is pivotably fitted in the expanding wedge (7), while the fixed stop (4a) associated with it is formed on the opposite segment (4)

Description

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The invention relates to a winding drum of a reel for tapes with at least two segments which can be expanded by an expansion wedge arranged between them and a clamping element which is arranged on the circumference of the drum within its periphery and carried by the expansion wedge and which is designed as a strip and which is loaded by an actuator a fixed stop formed on the opposite segment has a clamping effect on the beginning of a tape.

The advantage of such a known winding drum (DE-AS 1 090 618, in particular Fig. 6) is that the clamping element is actuated simultaneously by actuating the expanding wedge and the drum has a closed cylinder surface in the spread state. In this known winding drum, the strip-like clamping element is rigidly fixed to the expanding wedge. It is designed as a U-shaped clamping rail, the connecting web of which forms part of the periphery of the expanding wedge and the outer, free and resilient trained leg in the outer operating position of the expanding wedge with the stop formed on the opposite segment has a clamping effect on a band start.

To ensure that the beginning of the band is also held securely, the outer leg and the opposite stop are designed in the manner of a tongue and groove connection, as a result of which the beginning of the band is clamped in a positive manner. This type of holding the beginning of the tape is not optimal because the holding of the beginning of the tape is primarily based on positive locking. In the case of tapes that have a high resistance to deformation, there is a risk that the spring force of the U-shaped clamping rail is not sufficient to bring about a positive connection. An even greater disadvantage is that with this type of clamping element there is no strip thickness compensation and no smooth transition in the region of the clamping element for the strip to be wound up. Since the tape is brought directly to the outer periphery of the drum due to the fixed position of the connecting web and the shape of the clamping element when it emerges from the slot formed by the stop and by the clamping element, a relatively rugged step results for the next layer in the area of the clamping element . What is desired, however, is a transition that is as smooth as possible for the belt both when it exits the slot and for the next layers. If the clamping element with a larger radius of curvature were to pass from the slot into the periphery of the drum, this would have the disadvantage that there would be a larger unsupported area at the slot for the next layer. Finally, with this known winding drum, only tapes in a very limited thickness range can be wound. Vastly different thicknesses can lead to the spreading wedge being moved too far for a sufficient clamping force for thin strips and too little radially for thick strips, which is why there is a step at the transition from the spreading wedge into the periphery of the drum. Furthermore, a winding drum is known (DE-AS 11 89 352), in which a pivotable clamping element which is spring-loaded in the clamping direction is mounted in a slot of the drum. In order to move the clamping element against the spring force into the release position, a radial adjusting wedge is provided, which is supported on an inclined surface by an axial expanding wedge for the segments. With this different type of drum, there are no problems with regard to a smooth transition into the periphery of the drum because of the lack of an expanding wedge for the beginning of the band, because the parts forming the transition, unlike in the generic state of the art of the movable expanding wedge, are fixed parts of the drum, and the elements involved in the clamping are completely inside the drum; however, this is paid for with the necessity that a pivotable bar is provided on the periphery, which bridges the recessed exit of the beginning of the tape from the drum in order to keep the unsupported area as small as possible. This bar remains pivoted to a greater or lesser extent, depending on the thickness of the band, so that a smaller or larger step can result for the next band layer at this point.

The invention has for its object to provide a winding drum of the type mentioned, in which there is a smooth transition into the periphery of the drum or to the respective lower layer for tapes of different thicknesses both for the beginning of the tape and the next tape layers.

This object is achieved in that the clamping element is pivotally mounted on the expanding wedge in such a way that it forms a smooth transition in the region of the clamping element for the band to be wound up in each pivoting position-dependent pivot position. Because of the use of a clamping element arranged on the periphery of the drum and pivotably mounted on the expanding wedge, tapes of different thicknesses can be securely clamped in and ensure a smooth transition into the winding periphery both for the beginning of the tape and for the subsequent winding. This is possible because the adaptation to different strip thicknesses takes place via different degrees of pivoting of the clamping element. The transition of the clamping element into the periphery of the drum is practically the same for all swiveling degrees. This is why there is a smooth transition in the area of the clamping element and no larger, unsupported area, even with bands of different thicknesses for the subsequent winding (second layer). Another advantage is that regardless of the thickness of the band, the expanding wedge can be moved into its outer defined position, in which the segments form a closed, round cylinder jacket with the expanding wedge. Finally, there is also a high clamping force, because in addition to the force of the actuator, the tensile force of the band also acts in the closing direction of the clamping element.

The actuator of the clamping element can be designed differently. For example, hydraulic cylinder piston units or pneumatic air bellows. It is advantageous for the function if there are resilient elements. In this embodiment, the clamping is effected with the movement of the expansion wedge, without the need for special, controllable actuators.

In the case of longer terminal strips (extending transversely to the band run), it is advantageous to adjust several actuators over the length of the terminal strip in order to prevent the terminal strip from bending during clamping. A tubular air bellows could be arranged over the entire length of the terminal block.

According to a further embodiment of the invention provided that the clamping element is mounted on an at least partially hollow round rod in which the spring designed as a torsion bar is arranged. Through the use of this hollow round bar and the integrated torsion bar spring, you not only get a high clamping force, but the parts are also optimally designed, since the round bar not only forms the bearing for the swiveling clamping part, but also accommodates the spring. This construction is therefore also protected against contamination and requires little maintenance.

In the simplest case, the terminal strip is made in one piece. However, since on the one hand strips have a non-uniform strip thickness profile due to the rolling process, and on the other hand the parts involved in the strip clamping are subject to uneven wear across the drum width, the strip is not securely clamped with a one-piece clamping strip. The effect is an uneven clamping force across the bandwidth and a resulting uneven tensile strength of the clamped band. When the strip strips of a slit strip are wound together within a slitting line, individual strips may even not be pinched. The winding process is then considerably disturbed or impossible.

According to one embodiment of the invention, these difficulties can be avoided by the fact that the clamping element, which is designed as a strip, has a longitudinal direction, i.e. transverse to the band, is divided several times, i.e. consists of several independently pivotable sections that are individually loaded with actuators.

An approximately the same result is achieved if a one-piece terminal strip is interrupted transversely to its length over a large part of its cross section, so that it does is still in one piece, but the individual parts connected by the remaining cross-section can be moved relative to one another as if by means of a joint which can be moved to a limited extent. The mode of operation of this bar then corresponds to a bar with increased elasticity.

Alternatively, it is also possible in the case of an undivided strip that a divided or elastic one-piece support strip is arranged on the clamping element or the stop, the parts of which are individually spring-supported or which is spring-supported at appropriate intervals.

With all the alternatives it is ensured that a uniform clamping force for the strip tension acts on the undivided strip or the longitudinally divided strip even with an uneven strip thickness profile or wear across the strip.

The winding drum according to the invention can be used for both right and left winding if a further clamping element is installed in a further expansion wedge with the opposite orientation to the first clamping element and cooperates with a stop formed on the opposite segment.

In the winding drum according to the invention, an absolutely circular, closed periphery can also be obtained for the spread position of the segments. The winding drum should preferably consist of two, three or four expandable segments with expansion wedges.

The invention is explained in more detail below with reference to a drawing showing two exemplary embodiments.

1 shows a winding drum in the spread state in

Axial section, in the upper part through a Segment and in the lower part by a simple expanding wedge,

FIG. 2 shows the winding drum according to FIG. 1 in the spread state in an axial half-section through an expanding wedge equipped with a clamping element,

3 shows the winding drum according to FIGS. 1 and 2 in the spread state in half cross-section,

FIG. 4 shows the winding drum according to FIGS. 1 and 2 in the non-spread state in half cross-section,

5 shows the winding drum according to FIGS. 1 and 2 with the band beginning clamped in an enlarged section in cross section, and

6 shows a winding drum in an embodiment modified from the winding drum of FIGS. 1 to 5 with a clamped band beginning in an enlarged cross-section.

The winding drum consists of a hollow core 1, four segments 2, 3, 4 radially movably mounted thereon and spreading wedges 5, 6, 7 which act on these segments 2-4 and are arranged between segments 2-4 moved radially outward, as will be described, they then have a spreading effect on the segments 2, 3, 4, so that they move from the inner position shown in FIG. 4 to the outer position shown in FIGS. 1-3, 5 and 6 .

As best shown in FIG. 1 for segment 2, each segment 2-4 is guided on the core 1 by means of radially arranged guide pins 8a, 8b, 8c, 8d, 8e and preloaded in the radial direction to the axis by means of diaphragm springs 9a, 9b, 9c, 9d loaded bolts 10a, 10b, 10c, 10d. By means of the plate springs 9a-9d and the bolts 10a-10d, the segments 2-4 are thus preloaded against the spreading force of the expansion wedges 5-7 acting on them or are retracted inward when despreading.

The expansion wedges 5-7 are mounted in axial guide grooves la, lb, lc of the core 1 and consist of two strips 5a, 5b, 6a, 6b, 7a, 7b which are in engagement with a sawtooth profile. While the outer strips 5a-7a of the expansion wedges 5-7 are held axially immovably between end holding elements 11, 12 but are radially displaceable, the inner strips 5b-7b are radially immovable but axially displaceable. For the purpose of displacement, they are connected to a main 13 arranged on one end face. This main 13 can be designed as a double-acting cylinder piston, so that the inner strips 5b-7b can be axially displaced by its action, which results in a radial displacement of the outer strips 5a-7a.

The expansion wedge 7 differs from the expansion wedges 5 and 6 in its outer bar 7a. This bar 7a comprises a strip-like clamping element 14 pivotably mounted on it. This clamping element 14 acts together with a stop 4a formed on the segment 4. The strip-shaped clamping element 14 is pivotally mounted on an at least partially hollow round rod 15 and in the outer part 7a of the expansion wedge 7.

In the round rod 15 there are preferably accommodated two springs 16a, 16b designed as torsion rods, which are fixed at one end in the round rod 15 and are connected at the other end to the end faces of the clamping element 14. That way it will Clamping element 14 both held and preloaded in the clamping direction.

If, as shown in FIG. 5, the beginning 17 of a band is pushed in up to a stop 18 on the segment 4 and the expanding wedge 7 is moved from the position shown in FIG. 4 to the position shown in FIGS. 3, 5 and 6, then it clamps the clamping element 14 in cooperation with the abutment 4a under tension of the torsion bars 16a, 16b the beginning of the tape 17. As FIG. 5 shows, the pivotable mounting of the clamping element 14 and its shape result in a smooth transition into the periphery of the drum. In addition, there is in any case only a small unsupported area at the slot. This applies to both thinner and thicker tapes. Only the degree of pivoting of the element is different. Since the pivot bearing of the clamping element 14 lies opposite the slot formed by the clamping element 14 and stop 4a, the different degree of pivoting has practically no effect on the position of the part of the clamping element 14 adjacent to the pivot bearing in the periphery of the drum, so that no step is produced here either.

Because of the resilient support of the clamping element 13, the clamping in the radial movement of the expansion wedges 5, 6, 7 can take place very early, without undesirably high clamping forces resulting from a further radial movement which may be necessary due to the spreading.

In order to apply a uniform clamping force in the case of a thickness that is different across the width of the band, both in the case of an undivided band and a longitudinally divided band, the clamping surface of the stop 4a or the clamping surface of the clamping element 14 can be equipped with a support bar which is divided in the longitudinal direction and is not shown in the drawing be, the parts of which are individually spring-supported. This embodiment is shown in FIG alternative embodiment shown, in which the clamping element 14 itself is composed of several sections in the longitudinal direction. The individual sections are loaded by a compression spring 14a. With this version, the torsion spring is not required. However, as in the first exemplary embodiment, the individual pieces of the clamping element 14 are pivotably mounted on the round rod 15, which is full in this case.

Claims

Expectations

1. winding drum of a reel for tapes with at least two segments (2, 3, 4) which can be expanded by an expansion wedge (5, 6, 7) arranged between them and a bar which is arranged on the circumference of the drum within its periphery and carried by the expansion wedge Clamping element (14), which, loaded by an actuator (16a, 16b), has a fixed stop (4a) formed on the opposite segment (4) and has a clamping effect on the beginning of a tape, characterized in that the clamping element (14) on the expanding wedge ( 7a) is pivotally mounted in such a way that it forms a smooth transition in the region of the clamping element (14) for the tape to be wound up in each pivoting position-dependent pivot position.

2. winding drum according to claim 1, d a d u r c h g e k e n n z e i c h n e t that the actuator is a spring.

3. winding drum according to claim 1 or 2, so that the clamping element (14) is mounted on an at least partially hollow round rod (15) in which the spring (16a, 16b) designed as a torsion rod is arranged.

4. winding drum according to one of claims 1 to 3, characterized in that on the Clamping element (14) or the stop (4a) is arranged a support bar divided in the longitudinal direction, the parts of which are individually resiliently supported.

5. winding drum according to one of claims 1 to 3, d a d u r c h g e k e n n z e i c h n e t that the clamping element (14) consists of several, independently pivotable, individually spring-loaded sections.

6. winding drum according to one of claims 1 to 5, d a d u r c h g e k e n n z e i c h n e t that a further clamping element is installed in a further expansion wedge with the clamping element (14) opposite orientation and cooperates with a stop formed on the opposite segment.