The invention relates to a clamping device for supporting a reel having a tubular core. The clamping device comprises a base body with a mounting interface for fixing the base body on a machine frame and a carrier body configured for being placed inside the tubular core of the reel. The carrier body is rotatably supported on the base body such that the carrier body can rotate with respect to the base body about an axis of rotation. Furthermore, the clamping device comprises a plurality of clamping elements being coupled with an actuation mechanism such that the clamping elements can selectively protrude from an outer circumference of the carrier body and selectively be retracted to be at least flush with the outer circumference of the carrier body.

Such clamping devices are known. They are for example used in web material processing machines. In such machines the web to be processed is provided on reels having a tubular core. In order to process the web, the reel needs to be supported within the web material processing machine. This is for example done by using one or two clamping devices. In the first case, the clamping device supports the reel at one end thereof. In the latter case, each of the clamping devices supports one end of the reel such that the reel is supported on both sides.

An example of a web material processing machine is a hot foil stamping machine. Thus, the web material to be processed is a foil made from polymer material.

It is also known that within a web material processing machine, the web material to be processed needs to be tensioned in a predefined manner. This is done in order to allow for accurate and repeatable processing of the web material. To this end, known clamping devices comprise an interface for being connected to an external brake mechanism. Such an interface for example comprises a wheel which is able to engage a geared wheel or a belt of the brake mechanism. US2,405,637, CN110203771 or US3,381,912 are examples of such devices. Other devices, for example CN110203772 provide a brake within the clamping device, at the tip of a clamping device inside the axle of the reel. The problem to be solved by the present invention is to improve known clamping devices. In particular, a clamping device shall be provided which is compact.

The problem is solved by a clamping device of the type as mentioned above, which comprises a brake mechanism being arranged between the base body and the carrier body for selectively decelerating or blocking the rotation of the carrier body with respect to the base body. In this context, being arranged between the base body and the carrier body is to be understood in a functional manner, i.e. the brake mechanism couples the base body and the carrier body. Moreover, in contrast to known clamping devices the brake mechanism is now integrated into the clamping device. Thus, the brake mechanism is a functional and structural unit of the clamping device. This renders the clamping device compact, especially when comparing it to the combination of a known clamping device and a known brake mechanism connected thereto. Additionally, the clamping device according to the invention is easy to mount within a web material processing machine since all efforts related to the connection of a known clamping device to a know brake mechanism can be eliminated. Furthermore, less parts are necessary in a clamping device according to the invention.

Preferably, the carrier body is supported on the base body via at least two separate bearing members. Especially the at least two separate bearing members are at least two separate roller bearing members. Consequently, the carrier body and the base body are connected in a mechanically stable and reliable manner. This leads to a long service life of the clamping device. Moreover, such a clamping device is especially well suited for supporting heavy reels.

The carrier body may be sleeve-shaped or cup-shaped, wherein a portion of the base body extends into an interior of the carrier body. This leads to a compact design of the clamping device.

According to an embodiment, the brake mechanism comprises a plurality of disks forming a stack which generally extends along the axis of rotation. The disks are rotationally fixed on the base body or on the carrier body respectively in an alternating manner. Thus, the brake mechanism comprises a multiple disk brake. Such brakes can provide high braking torques while requiring comparatively little space. Moreover, such brake mechanism are reliable in operation. The brake mechanism may comprise a loading arrangement for generating and/or adjusting a brake torque to be effective between the base body and the carrier body. When the clamping device is used for supporting a reel carrying web material, the tension of the web material can be adjusted by adjusting the brake torque. Thus, the loading arrangement makes the clamping device suitable for supporting reels carrying a wide variety of web material to be processed.

According to a variant, the loading arrangement comprises one or several magnets that generate a brake torque caused by eddy currents in a disk. Consequently, a well-defined brake torque can be generated by setting the distance between the magnet and the disk.

According to a variant, the loading arrangement comprises a compression member for compressing the stack of disks in order to generate a brake torque. Consequently, a well-defined brake torque can be generated by compressing the stack of disks in a predefined manner. In doing so, the brake torque can also be adjusted in a precise and reliable manner.

The compression member may be a compression ring cooperating with the base body via a screw thread and acting on the stack of disks via at least one spring element. A middle axis of the compression ring preferably corresponds to the axis of rotation of the carrier body. Consequently, the clamping device is simple and compact in design. The use of a screw thread and a spring element facilitate the precise adjustment of the brake torque. The compression ring may be operated either by hand or by a tool. In the latter case the tool is preferably a standard tool.

In an alternative, a cantilevered end of the carrier body and the loading arrangement are arranged opposite each other. In this context, the cantilevered end of the carrier body is the end being configured for protruding into the tubular core of the reel when the clamping device is in use. Thus, in operation, the loading arrangement is also arranged at an end of the clamping device being opposed to the reel. Consequently, the loading arrangement may be easily accessed, e.g. for adjusting or re-adjusting the brake torque.

In an example, the clamping elements are positioned closer to a first, cantilevered end of the carrier body than to a second end of the carrier body, being arranged opposite the first end. Again, the cantilevered end of the carrier body is the end being configured for protruding into the tubular core of the reel when the clamping device is in use. Consequently, the clamping elements are configured to be arranged at a certain distance from the rim of the tubular core of the reel to be supported by the clamping device. Thus, the clamping elements engage the tubular core at a certain axial depth. This is especially the case when comparing the clamping device according to the invention to a known clamping device, wherein the clamping elements are arranged such that they are always positioned in close proximity to a rim of the tubular core of a reel supported on the clamping device. The clamping device according to the invention is configured for supporting reels with enhanced reliability.

Preferably, the actuation mechanism comprises a push member and the clamping elements are arranged between the carrier body and the push member along the axis of rotation. The push member is selectively movable with respect to the carrier body along the axis of rotation. Thus, the clamping elements may selectively be brought into a state in which they protrude from the outer circumference of the carrier body by moving the push member towards the carrier body. Furthermore, the clamping elements may be spring biased such that they retract into a position in which they are at least flush with the outer circumference of the carrier body, when the push member is departed from the carrier body.

Preferably, the push member is generally plate shaped. Thus, the push member is compact and easy to manufacture.

Each of the clamping elements may abut against the carrier body and the push member via respective contact faces which are inclined with respect to the axis of rotation and with respect to a corresponding radial direction such that the clamping elements can be pushed radially outward if the push member approaches the carrier body and can be retracted if the push member departs from the carrier body. Using inclined contact faces is a simple and reliably manner of translating the axial movement of the push member into a radial movement of the clamping elements.

In another embodiment, the clamping element may be a tubular ring (an air chamber), where the addition of pressure inflates the ring, which protrudes into the tubular core of the reel to block the reel. Alternatively, instead of adding some pressure into the air chamber, the air chamber can be caused to protrude by a push member like in the former embodiment. Alternatively, when using the push member, the air chamber may be replaced by a deformable ring, for example a rubber ring, whose deformation can block the reel.

The actuation mechanism can comprise a screw member connecting the carrier body and the push member and generally extending along the axis of rotation in order to selectively move the push member. Thus, the push member is moved by turning the screw member. Consequently, the push member may be moved in a precise and simple manner.

In an embodiment, the screw member is accessible from an end of the clamping device being opposed to a cantilevered end of the carrier body. Once more, the cantilevered end of the carrier body is the end being configured for protruding into the tubular core of the reel when the clamping device is in use. Thus, when a reel is supported on the clamping device, the screw member is still accessible from an end of the clamping device being opposed to the reel. In other words, a reel supported on the clamping device does not hinder the access to the screw member. Consequently, reels can be comfortably clamped and un-clamped.

Along the axis of rotation, a tool interface of the screw member may be arranged in an axial section being defined by the axial extension of the brake mechanism. Thus, the axial section in which the tool interface is provided, ranges from a first axial end of the brake mechanism to a second axial end of the brake mechanism, wherein the first end and the second end are axially opposed to each other. Preferably, the tool interface is arranged radially inside the brake mechanism. The tool interface is thus provided in a position which is relatively close to an axial end of the clamping device which is opposed to the end which is configured for protruding into the tubular core of a reel. Thus, the tool interface is easily accessible during operation of the clamping device.

In a preferred example, the tool interface is accessible from the same axial side on which the loading mechanism is provided.

The invention will now be explained with reference to an embodiment which is shown in the attached drawings. In the drawings,

- Figure 1 shows a reel having a tubular core and carrying a web material, wherein the reel is supported on two clamping devices according to the invention, - Figure 2 shows an exemplary one of the clamping devices of Figure 1 in a perspective view, and

- Figure 3 shows the clamping device of Figure 2 in a sectional view.

Figure 1 shows a reel 10 having a tubular core 12 on which a web material 14 is wound. In the present example the web material is a polymer foil.

The reel 10 is supported on a machine frame 16 of a web material processing machine via two clamping devices 18. In this context, the frame 16 is only represented in a schematic manner.

Both clamping devices 18 are identical.

Consequently, only one exemplary clamping device 18 will be explained with reference to Figures 2 and 3. These explanations obviously apply to both clamping devices 18 shown in Figure 1.

The exemplary clamping device 18 comprises a base body 20.

On the base body 20 a mounting interface 22 is provided for fixing the base body 20 on the machine frame 16.

In the example shown in the figures, the mounting interface 22 comprises a mounting arm 24.

At an end of the mounting arm 24 which is to be connected to the machine frame 16, two mounting slots 26a, 26b are provided.

The base body 20 also comprises a substantially ring-shaped member 28 which is fixedly connected to the mounting arm 24.

Moreover, the base body 20 comprises a tubular support member 30 which is immovably mounted on the ring-shaped member 28.

The tubular support member 30 extends through the interior of the ring-shaped member 28 and protrudes from the ring-shaped member 28.

On the protruding portion of the tubular support member 30 two bearing members 34a, 34b are provided and a carrier body 36 is rotatably supported on the tubular support member 30 via these bearing members 34a, 34b. In the present example the bearing members 34a, 34b are roller bearing members which are positioned such that a certain distance is provided between them.

Consequently, the carrier body 36 can rotate about an axis 38 of rotation with respect to the base body 20.

In other words, the carrier body 36 is rotatably supported on the base body 20.

The carrier body 36 is substantially cup-shaped, wherein an open end thereof is oriented towards the ring-shaped member 28 of the base body 20 such that a portion of the tubular support member 30 of the support body 20 is received inside the interior of the carrier body 36.

At a closed end of the cup-shaped carrier body 36 a generally plate-shaped push member 40 is provided.

Along the axis 38 of rotation, i.e. axially, in between the carrier body 36 and the push member 40 a plurality of clamping elements 42 are arranged.

Each of the clamping elements 42 is generally plate-shaped and substantially is oriented in an axial and radial direction with respect to the axis 38 of rotation.

Along a circumference of the carrier body 36 and the push member 40 the clamping elements 42 are arranged in a regular pattern. This means that neighboring clamping elements 42 have substantially the same angular distance respectively.

A circumferentially outer surface 44 of each of the clamping elements 42 comprises a sharp tip 47. Preferably, the outer surface 44 of each of the clamping elements 42 is provided with a toothed pattern 46 which facilitates the clamping of the reel 10 as will be explained later. The sharp tip as well as the toothed pattern are especially well adapted for a reel having an axle made of soft material, for example cardboard, by penetrating the axle and providing very tight clamping.

Axial end faces 48, 50 of the clamping elements 42 are inclined with respect to a radial direction and with respect to an axial direction defined by the axis 38 of rotation. The axial end faces 48 which are oriented towards the carrier body 36 abut against corresponding contact faces 52 of the carrier body 36 which are also inclined with respect to the axis 38 of rotation and with respect to a corresponding radial direction.

The axial end faces 50 which are oriented towards the push member 40 abut against corresponding contact faces 54 provided on the push member 40. These contact faces 54 are inclined with respect to the axis 38 of rotation and with respect to a corresponding radial direction.

The above-mentioned inclinations are oriented such that the clamping elements 42 are pushed radially outward if the push member 40 approaches the carrier body 36 and can be radially retracted towards the axis 38 of rotation if the push member 40 departs from the carrier body 36.

Moreover, each clamping element 42 comprises an opening 56, wherein two holding rings 58, 60 are arranged such that they extend through the openings 56 of all of the clamping elements 42.

The holding rings 58, 60 also pre-load the clamping elements 42 radially inwards, thus the axial end faces 48, 50 of the clamping elements 42 are always kept in abutment with the corresponding contact faces 52, 54.

The carrier body 36 and the push member 40 are biased in an axial direction away from each other by a spring element 62.

However, against the force of the spring element 62, the push member 40 and the carrier body 36 are connected via a screw member 64.

The screw member 64 generally extends along the axis 38 of rotation.

The screw member 64 threadedly engages the push member 40 and extends through the carrier body 36 such that a head 66 of the screw member is positioned on a side of the carrier body 36 which is opposed to the push member.

Consequently, the push member 40 can be selectively moved relative to the carrier body 36 by turning the screw member 64. On the side of the carrier body 36 which is opposed to the push member 40, an elongate sleeve 68 is provided and the screw member 64 extends through the sleeve 68.

Thus, the head 66 of the screw member 64 is arranged at a certain distance from a bottom portion of the carrier body 36 which essentially corresponds to an axial length of the sleeve 68.

This leads to a configuration in which the head 66 of the screw member 64 and especially a tool interface 70 arranged on the head 66 is accessible from an end of the clamping device 18 being opposed to a cantilevered end 72 of the carrier body 36.

In the example shown, the cantilevered end 72 of the carrier body 36 corresponds to the end where the push member 40 is provided.

This design renders the tool interface 70 accessible by a standard tool 74 which is represented in Figure 3 by an Allen key.

In contrast thereto, the clamping elements 42 are positioned in proximity to the cantilevered end 72 of the carrier body 36.

The push member 40, the screw member 64, the carrier rings 58, 60 and the inclined faces 48, 50, 52, 54 thus form an actuation mechanism 76 for the clamping elements 42.

Using the actuation mechanism 76, the clamping elements 42 can selectively protrude from an outer circumference of the carrier body 36 and selectively be retracted to be at least flush with the outer circumference of the carrier body 36.

The carrier body 36 and the push member 40 are configured for being placed inside the tubular core 12 of the reel 10. In this context, the carrier body 36 and the push member 40 are preferably moved into the inside of the tubular core 12 with the clamping elements 42 being retracted.

Once arranged inside the tubular core, the clamping elements 42 may be moved to the protruding position by turning the screw member 64. Consequently, the clamping elements 42 will engage the tubular core 12. More precisely, the toothed patterns 46 will engage an interior circumference of the tubular core 12 thereby holding the reel 10.

The clamping device 18 also comprises a brake mechanism 78 being arranged between the base body 20 and the carrier body 36 for selectively decelerating or blocking the rotation of the carrier body 36 with respect to the base body 20.

The brake mechanism 78 comprises a multiple disk brake 80 having a plurality of disks forming a stack 81 which generally extends along the axis 38 of rotation.

According to the working principle of a multiple disk brake the plurality of disks comprises so-called outer disks 82 which are rotationally fixed on the ring-shaped member 28 of the base body 20 and so-called inner disks 84 which hare rotationally fixed on the carrier body 36. In the present example, the inner disks 84 are coupled with a support member 86 of the carrier body 36.

The inner disks 84 and the outer disks 82 are arranged in an alternating order along the axis 38 of rotation.

Both the inner disks 84 and the outer disks 82 are axially movable to a certain extend.

The brake mechanism 78 also comprises a loading arrangement 88 for generating and/or adjusting a brake torque to be effective between the base body 20 and the carrier body 36.

To this end, the loading arrangement 88 comprises a compression member 90 for compressing the stack 81 of inner disks 84 and outer disks 82 in order to generate a brake torque.

In the example shown the compression member 90 is a compression ring 92 cooperating with the base body 20 via a screw thread 94 and acting on the stack 81 of disks 82, 84 via a plurality of spring element 96.

For reasons of better visibility, only one spring element 96 is represented in Figure 3 in a schematical manner. In reality, the clamping device 18 comprises 3 to 5 spring elements 96 which are equally distributed over a circumferential direction. Alternatively, the spring element 96 may be replaced by any elastically compressible element, for example a piston.

More precisely, the screw thread 94 of the compression ring 92 engages a screw thread 98 being provided on a sleeve member 100 of the base body 20 which his fixedly connected to the ring-shaped member 28 and the tubular support member 30.

Thus, by turning the compression ring 92 with respect to the sleeve member 100 the spring elements 96 may be compressed such that the stack 81 of inner disks 84 and outer disks 82 is compressed. As a consequence thereof, a brake torque is increased.

If the compression ring 92 is turned in an opposite direction, the spring elements 96 are de-com pressed. Consequently, a brake torque is reduced.

In the example shown in the figures, the cantilevered end 72 of the carrier body 36 and the loading arrangement 88 are arranged opposite each other. This means that the loading arrangement 88 and the cantilevered end 72 of the carrier body 36 are positioned at opposing axial ends of the clamping device 18.

Moreover, the tool interface 70 of the screw member 64 and the brake mechanism 78 may be arranged such that the tool interface 70 is located in an axial section S of the clamping device 18 being defined by the axial extension of the brake mechanism 78, such that when the tool 74 is inserted into the tool interface, the tools protrudes by a margin from the stub. This margin avoid any interference between the tool and the stub, while avoiding to protrude too much.

In the example shown, a first axial end of the brake mechanism is defined by the compression ring 92 and a second axial end of the brake mechanism 78 is defined by the inner brake disk 84 having the biggest distance from the compression ring 92.

When considering the direction of the axis 38 of rotation, the tool interface 70 is arranged between these axial ends.