EP1960298B1 - Device for maintaining a constant tension on a web material - Google Patents

Abstract

The invention relates to an apparatus for maintaining a constant tension on a web of material, in particular on a label web used in a labeling machine (E), said apparatus comprising: a stationary rotary axle device (30) with a geometric rotational axis (M) and a tension compensation device (40) rotatable from a starting position about said rotational axis (M) of said rotary axle device (30), said tension compensation device (40) comprising a force unit (60) which exerts a force on the tension compensation device (40) that counteracts the rotational movement of the tension compensation device (40) from the starting position. It is further provided that the force applied by the force unit (60) is a linear force acting on the tension compensation device (40) at a force application point (65) with a radial spacing to the rotational axis (M) of the rotary axle device (30).

Description

The present invention relates to a device for maintaining a constant tension on a material web, in particular to a label web used in a labeller, according to the preamble of claim 1.

In practice, it is often necessary to keep the tensile stress, which acts on a conveyed material web, at least approximately constant. For example, this is the case with labeling machines, by means of which, among other things, self-adhesive labels are removed from a label carrier web and applied in a positionally accurate manner to products to be labeled. The label carrier web is wound into a roll and is withdrawn from this by means arranged downstream of the label roll drive rollers and the dispensing edge of the labeller, where the labels are detached from the label carrier web fed. The labels can be unprinted or already printed. In the former case, a printing unit is arranged in front of the dispensing edge.

During use of a label roll reduces its diameter, so that reduces the weight of the label roll and thus also the Mass inertia or the moment of inertia of the label roll decreases. However, the inertia has a great influence on the precision of the Appliziervorgangs, ie on the precision when applying the label on a moving past the dispensing edge product. The speed of the product can be up to 40m / s, for example, so that the label web and thus the label roll from a standstill must be accelerated to this speed. Although at the beginning of the use of the label roll the existing initial inertia in the setting of the Etikettiergeräts be taken into account, however, changes, as mentioned above, the inertia with increasing use of the label roll.

In order to compensate for the tensile stress that also changes as a result of this change in diameter when changing the diameter of the label roll with the consequences described above, it is known in practice to interpose a so-called dancer arm between the label roll and the dispensing edge the label carrier web is passed. This dancer arm may be a pivotable lever which is hinged at its one end rotatably to the housing of the Etikettiergeräts and at its other end with a roller around which the label carrier web is guided, is provided. Furthermore, this dancer arm is biased to its original position by a torsion spring. If the tensile stress on the label carrier web is increased, the dancer arm is deflected out of its initial position counter to the spring force of the torsion spring and counteracts an increasing torque of the deflection movement with increasing deflection.

It has proven to be disadvantageous here that the resistance which the dancer arm opposes, possibly changing, in particular increasing tensile stress, is not constant over its entire range of motion, so that as a result the tension of the label carrier web is also not constant. In addition, the life of a torsion spring is relatively low, so that after a short time, the torsion spring must be replaced or breaks during operation so that the labeller is no longer applicable. Furthermore, the torsion spring is a relative one complicated component, which increases the cost of the Etikettiergeräts both because of the measures necessary for their assembly on the labeling and their relatively expensive procurement.

It is an object of the present invention to provide a device of the type mentioned, which provides a cost-effective solution for a tensile stress compensation with a simple structure.

The above object is solved by the features of claim 1. In the subsequent claims 2 to 15 are advantageous embodiments of this.

The embodiment of the device according to the invention for maintaining an at least approximately constant tension on a material web, preferably a label web used in a labeling device includes: a stationary rotary axis device with a geometric axis of rotation and a rotatable from a starting position about the axis of rotation of the rotary axis device Zugspannungsausgleichseinrichtung having a power unit , which exerts a rotational movement of the Zugspannungsausgleichseinrichtung from the initial position counteracting force on the Zugspannungsausgleichseinrichtung. In this case, the force of the power unit is a force acting on the tension compensation device at a force application point with a radial distance to the rotational axis of the rotary axis device, linear acting force.

After this, there is the possibility that the tension compensation device can be very simple and therefore very inexpensive. For it is generally true that force generating devices that produce a linear force, are very easily permitted and can therefore be produced inexpensively. In addition, the to be provided in the Zugspannungsausgleichseinrichtung mounting devices for the power unit also have a simple structure, which in turn can reduce the total cost of the device on which the device according to the invention is used. The tensile stress, which is caused by the device according to the invention and which compensates for causes the tension that acts on the material web of the device, in which the device according to the invention is used, and which can change during the useful life of the web for various reasons, as mentioned above, by a torque, which is the rotational movement of the Zugspannungsausgleichseinrichtung from your initial position counteracted, caused. In other words, a torque which counteracts the movement of the tension compensation device from its starting position is generated by the relatively simply constructed force unit, which generates a linearly acting force, and the distance between the force application point of this force unit and the axis of rotation of the rotary axis device.

It is advantageous if the force unit is pivotable in the force application point with respect to the Zugspannungsausgleichseinrichtung. As a result, the trajectory of the power unit relative to the trajectory of the articulation point of the power unit to the tension compensation device may be different. If the other support point of the power unit is held stationary, but by which the power unit can also pivot, the power unit can optionally be actuated by the pivoting of the tension compensation device.

An inventive idea of the present proposal is that lines of action of the force generated by the force unit includes an angle with the straight line defined by the rotation and center longitudinal axis and the force application point of the force unit, wherein it is preferred that the angle between 0 ° and 90 ° and in particular in Range is greater than 90 ° and less than 90 °. If the angle between the line of force of the linear force caused by the force unit and the radial distance between the axis of rotation and the force application point is variable, the force component derived from the force generated by the force unit can cause a torque acting on the tension compensation device , be controlled so that the torque caused thereby remains constant. In particular, it is preferred that the angle between the line of force caused by the force unit, linear acting force and the radial distance between the axis of rotation and the force application point is constantly changing and / or in particular becomes smaller.

In principle, the device according to the invention can be used in cases in which the course of the tensile stress acting on the material web is known over the period of use of the material web. For example, has been determined by previous experiments that decreases over the useful life of a web on this tensile stress with progressive use, by an appropriate design of the device according to the invention, the amount or height of the tensile stress generated by the power unit or the amount of increase the power unit generated torque accordingly. The same applies to a reverse situation.

Here, the change in the amount of the power unit can be controlled once via the power unit itself, as will be mentioned below. On the other hand, there is also the possibility of bringing about a change in the geometry of the force components a change. So it is conceivable, for example, that by a corresponding configuration, those force component of the force generated by the power unit, which causes a force acting on the Zugspannungsausgleichseinrichtung torque over the pivoting or rotating range of Zugspannungsausgleichseinrichtung changed, which in turn changes the torque. In principle, both an increase and a decrease in the amount of this force component as well as a combination thereof are possible. However, it is preferred that the amount of the force component of the force generated by the force unit, which causes the force acting on the Zugspannungsausgleichseinrichtung torque remains at least approximately the same and thus also the amount of the torque caused thereby remains at least approximately constant.

It can also be provided in addition thereto or alternatively, that the distance or the support distance between the axis of rotation of the rotary axis device and the power drive point on the tension compensation device changes at least partially via the rotational movement of the tension compensation device. By changing the distance, a change in the caused by the force of the power unit torque is effected, which counteracts the rotational movement of the Zugspannungsausgleichseinrichtung from its initial position due to the tensile stress acting on the material web. Likewise, this can be compensated by changing the distance, a change in the amount of the force component causing the torque, so that the overall resulting from this force component and the distance torque remains at least approximately constant. In this context, it is particularly advantageous if a constant change in the distance between the axis of rotation and the force application point over at least almost complete rotation of the Zugspannungsausgleichsrichtung. As already explained above, the amount or the magnitude of the force generated by the force unit can increase progressively or degressively or linearly. In the case of a progressive or linear increase, it is particularly advantageous if the distance between the axis of rotation and the power-drive point decreases during the rotational movement of the Zugspannungsausgleichsrichtung from its initial position.

If the course of the tension acting on the web during the period of use is unknown or fluctuates, that is. the tension increases or decreases, so a solution can be provided by the device according to the invention, in which the amount or the height of the force generated by the force unit changes over the period of use. Examples of such units of force are springs which have a non-linear spring rate, be it progressive or degressive.

By combining such a force unit with the above-mentioned idea, namely that the angle between the line of force along which the force generated by the force unit acts linear, and the support distance between the force application point and the axis of rotation is made changeable, there is the possibility of a at least approximately constant Torque, which counteracts the tensile stress acting on the web, to provide. The vote can be made in such a way that is changed with increasing amount or increasing amount of force generated by the force unit of the angle. In other words, with one and the same force unit, which causes a linearly acting force, achieved by the pivotable articulation on the Zugspannungsausgleichseinrichtung that despite increasing amount of linear force generated by the power unit, the torque acting on the Zugspannungsausgleichseinrichtung at least approximately constant, since by changing the angle, the respective force component that causes the torque; stays the same. By a corresponding geometric design of the system, this can, as will be explained in more detail, achieve.

As stated above, a change in the amount or amount of torque which counteracts the rotational movement of the tension compensation device from its home position with increasing tension on the web can be achieved by varying the magnitude of the force component of the force generated by the force unit, which is the torque causes, and / or caused by changing the distance between the force application point and the axis of rotation. It is first assumed that the amount or the height of the force generated by the power unit itself does not change, however, by a corresponding geometric configuration, the amount of the force component of this force, which causes the torque. As has already been explained above, this can be achieved by changing the angle between those force components into which the force generated by the force unit can be decomposed in a force parallelogram. Likewise, however, it is possible by means of the device according to the invention to keep constant the amount of the force component which causes the torque, or the distance between the force-driving point of the rotation axis, but the amount or the amount of force generated by the force unit over the course to change the rotational movement of the Zugspannungsausgleichseinrichtung at least in sections. Again, it is preferable if the amount or amount of by The force unit continuously changes the force generated over the course of the rotational movement of the tension compensation device, preferably increases. As also stated above, a particular inventive idea of the present proposal is that not only the amount of the force component of the force generated by the force unit, which causes the torque is changed or the distance between the rotation axis and the force application point is changed or Amount or the amount of force generated by the power unit is changed, but that both changes are coordinated. For example, this can be done by using a machine element as the force unit, which generates a linearly acting force which increases progressively or linearly with increasing load. Likewise, of course, a degressive increase is possible. Such a machine element is provided for example by a compression spring with a progressive spring rate.

The linear force generated by the force unit can be both a compressive and a tensile force. Since force units which generate a compressive force, as compared to tensile forces generating power units, often have a longer life, the device according to the invention is particularly preferred that the force of the power unit is a compressive force.

For the power unit, the most diverse machine elements can be provided. Thus, on the one hand there is the possibility that the force unit is formed by at least one spring, preferably a compression spring, which further preferably has a non-linear, in particular progressive spring rate. On the other hand, the force unit can be formed by at least one gas spring or at least one electromagnet. Of course, however, any other solution for the power unit through which a linear force can be caused used.

A particularly simple embodiment of the Zugspannungsausgleichseinrichtung with respect to the distance to the axis of rotation of the rotation axis device having force application point for the generated by the power unit, linear acting force can be achieved in that the Zugspannungsausgleichseinrichtung is rotatable about the axis of rotation of the rotary axis device, and the force application point is provided eccentrically to the axis of rotation of the rotary axis device. In this case, the force unit can be supported on the one hand at the point of force application of the Zugspannungsausgleichsrichtung and on the other hand at a force application point of a support unit.

If the force unit is, for example, a compression spring element, then it is advantageous if the force unit is held pivotably at its support or force application point of the tension compensation device. If, moreover, a support unit is provided, then it is furthermore advantageous if the power unit is articulated in each case with its supporting or force application point on the support unit and / or on the tension compensation device in each case in a pivotable manner.

If the material web whose tensile stress is to be held at least approximately constant, wound into a roll, it is also advantageous if at least one unwinding is provided, which is rotatably held about the rotation axis means at this. It is also advantageous if the unwinding unit is fixed axially fixed to the rotary axis device.

In order to reduce the influence of slippage, which could act between the unwinding unit and the material web wound into a roll, it is furthermore advantageous if the unwinding unit has clamping means for preferably slip-free, reversible clamping of the winding material.

So that preferably does not move automatically at a standstill of the material web, there is a further advantageous embodiment of the present invention is that a stationary brake unit is provided, the braking force preferably acts on the unwinding. Of course, however, the stationary brake unit can also act on another device or unit of the device according to the invention.

Since in particular at the beginning of a forward movement of the material web, the Zugspannungsausgleichseinrichtung is in its initial position and in this position an unintentional movement of the web is to be prevented, it is advantageous if the brake unit is located in its initial position Zugspannungsausgleichseinrichtung in its braking position.

The brake unit can be actuated by both active and passive elements. An active element is a motor drive, such as a hydraulic cylinder. In a passive element is a solution in which the operation of the brake unit is derived from the rotational movement of the Zugspannungsausgleichseinrichtung. In such a case, it is further preferred that the brake unit is reversibly movable from its braking position into its release position by means of at least one actuating element in movement and transmission connection with the tension compensation device. Here, the actuating element can be in operative connection with the Zugspannungsausgleichseinrichtung in such a way that the rotational movement of the Zugspannungsausgleichseinrichtung actuates the actuating element.

Furthermore, the brake unit should have a simple structure. When using an actuating element, this can be achieved by the actuating element acting directly on a brake shoe of the brake unit. In order to continue to have the option of being able to variably control the movement of the brake shoe as a function of the rotational position of the tension compensation device, the actuating element may be formed by a cam element whose cam surface preferably has a continuous surface course, but which has, for example, uneven radii of curvature.

A particularly simple actuation of the brake unit can be realized in that with the beginning of the rotational movement of the tension compensation device, the brake unit is releasable from its braking position. It is still here advantageous if the release of the brake unit from its braking position is continuous.

As already mentioned above, the brake unit can be actuated by active elements, for example a hydraulic cylinder. However, as has been explained in the introduction, in such devices for maintaining an at least approximately constant tensile stress, it is desirable for them to be constructed simply and therefore cost-effectively. In such a case, it is advantageous if the brake unit is biased in its braking position by means of at least one biasing element. It may also be advantageous that the biasing force of the biasing member is adapted to the force of the power unit in such a way that it is additively added thereto. If, for example, the force unit is a compression spring, it generally only has a very small force at the beginning of its spring travel. This initial gap in the force curve of the power unit can then be bridged by the biasing element of the brake unit.

For the bias of the brake unit, the most diverse machine elements can be used. It is advantageous if the bias of the brake unit by means of at least one spring element, preferably a tension spring is applicable.

In turn, different solutions can be provided for the construction of the brake unit. A particularly simple design of the brake unit can be achieved in that the brake unit is formed by a shoe brake, whose at least one brake shoe is rigidly connected to the rotary axle device, wherein the brake shoe acts on a non-rotatably connected to the unwinding brake drum. The brake drum can be arranged to be rotatable concentrically to the axis of rotation of the rotary axis device and the brake unit has two brake shoes, which are arranged symmetrically to the brake drum. As already mentioned, while the brake shoes can be biased by at least one tension spring in the braking position of the brake unit.

So that in particular the force unit for applying the linearly acting force is protected against damage, it can further be provided that the tension compensation device comprises a housing which at least partially encloses components of the rotation axis device and / or the force unit. In this case, it can furthermore be provided that the axis of rotation of the rotary axis device lies within the housing. Such an arrangement allows the weight distribution of the tension compensation device to be symmetrical with respect to the rotation axis of the rotation axis device. In this way, it can be achieved that the tension compensation device is designed such that it is independent of the position, i. in any position within the machine in which it is used can be arranged.

The housing can take any shape. Particularly preferred is when the housing in plan view has the shape of a quadrangle, preferably the shape of a rhombus, more preferably in the shape of a kite quadrangle. In this case, the intersection of the diagonals of the quadrilateral lie on the axis of rotation of the rotary axis device.

Fig. 1

eine perspektivische Ansicht eines Etikettiergeräts, bei der die erfindungsgemäße Vorrichtung Verwendung findet;

Fig. 2

eine perspektivische Explösionsdarstellung der erfindungsgemäßen Vorrichtung;

Fig. 3

eine Zusammenbauzeichnung der erfindungsgemäßen Vorrichtung, betrachtet von deren Vorderseite;

Fig. 4

eine Zusammenbauzeichnung der erfindungsgemäßen Vorrichtung, betrachtet von deren Rückseite; und

Fig. 5a - 5f:

verschiedene Darstellungen der erfindungsgemäßen Vorrichtung von der Vorder- und der Rückseite in unterschiedlichen Betriebspositionen.

Further advantageous embodiments and an embodiment of the device according to the invention are explained below with reference to the drawing figures. It should be noted that the terms "right,""left,""bottom," and "top" used throughout the specification refer to the drawing figures in an orientation in which the reference numerals and figure designations are normally readable. Here is:

Fig. 1

a perspective view of a Etikettiergeräts, in which the device according to the invention is used;

Fig. 2

a perspective Explösionsdarstellung the device according to the invention;

Fig. 3

an assembly drawing of the device according to the invention, viewed from the front side;

Fig. 4

an assembly drawing of the device according to the invention, viewed from the rear side; and

5a-5f:

different representations of the device according to the invention from the front and the back in different operating positions.

In Fig. 1 is a perspective view of a labeling E reproduced, in which the device 10 of the invention for maintaining an at least approximately constant tension on a material web - here a label carrier web - is used. The labeling apparatus E comprises, in addition to the device 10 according to the invention, a pressure / dispensing unit DS, which is arranged below the device 10 according to the invention. Furthermore, the labeling device E has a take-up unit A, on which the empty label carrier web, ie the carrier web is wound up after removal of the individual labels on the printing / dispensing unit DS. If the labels are already printed, then instead of the printing / dispensing unit DS, only one dispensing unit can be provided. Finally, the labeling device E has a control panel B entered by means of the operating commands in the labeling E and optionally the operating state of the labeling E can be read.

The label carrier web, not shown, is moved from an unwinding unit 20 to the bottom left toward a deflection roller 54 of the device 10 according to the invention which is explained in more detail below, and from there via further, unspecified rollers, which are partly drive rollers, to the print / Donation unit DS led. At the printing / dispensing unit DS, the individual labels of the label carrier web can either be printed and then dispensed or only dispensed if they are already printed. The empty label carrier web is, as already mentioned, guided at the printing / dispensing unit DS to the left rear to the take-up unit A.

As in particular from the Fig. 1 to 3 shows, the device 10 according to the invention for at least approximately keeping constant the tensile stress a material web as main assemblies a unwinding unit 20, a rotary axis device 30, a Zugspannungsausgleichseinrichtung 40, a power unit 60 and a brake unit 80. These main assemblies are hereinafter in connection with the FIGS. 1 to 4 explained in more detail.

The unwinding unit 20 has a in the Fig. 1 arranged in a vertical alignment bearing plate 22 which has a circular shape in plan view from the front. In order to save weight, the contact disk 22 is provided with slots 22a which extend radially or radially inward at a distance from the outer edge of the contact disk 22. How out Fig. 1 it can be seen, the radial length of the slots 22a is significantly smaller than the radius of the contact disk 22. Furthermore, the unwinding unit 20 has a clamping unit 24, which allows the slip-free clamping of a wound into a roll label carrier web. The clamping unit 24 has a conventional structure and will therefore not be explained in detail below.

The rotary axis device 30 has a non-illustrated housing frame of the labeller E or on the housing frame of any other device in which the device 10 according to the invention is used, rotationally mounted rotational axis, of which in the Fig. 2 only the geometric rotation and center longitudinal axis M is reproduced and the example of steel and the like. Can be made. In the in Fig. 1 shown arrangement of the device 10 according to the invention on the labeling E is the axis of rotation of the rotary axis device 30 at least approximately perpendicular from the vertically extending, unspecified housing level of the labeling E out and extends substantially horizontally. However, due to the particular inventive design of the device 10, as will be explained in more detail below, take the rotational and central longitudinal axis M of the axis of rotation or the axis of rotation itself any other arbitrary position. It should also be noted that the axis of rotation has at least approximately the shape of a circle in cross-section.

As in particular from Fig. 2 can be removed, the rotary axis device 30 further includes a largely flat, consisting of Stahlfeinguss support plate 32 which is rotatably and axially fixed to the axis of rotation of the rotary axis device 30 is connected. The support plate 32 has in plan view at least approximately the shape of the inverted Greek letter "Ω". Their thickness is much smaller than their diameter. The carrier plate 32 is used for attaching and supporting components of the brake unit 80, as will be explained in more detail below.

Furthermore, the support plate 32 has in its geometric center a in the assembled state of the device 10 according to the invention concentric to the rotational and central longitudinal axis M arranged and in plan view the shape of a circle having, central passage opening 34, which integrally formed in the direction of left facing and circumferentially equal edge 34a is provided. Through this passage opening 34, the axis of rotation of the rotary axis device 30 is inserted through.

In addition, the support plate 32 has at its lower edge a protrusion or material reinforcement 36. The material reinforcement 36 is provided with two Durchgangsdurchbrechungen 36 a, each having the shape of a lying, but slightly tilted in the circumferential direction of the support plate 32 oval in plan view and for attachment of Components of the brake unit 80 serve. The - two through openings 36a are symmetrically arranged on both sides by a vertically extending and passing through the center of the support plate 32, not shown symmetry line or symmetry axis of the support plate 32.

On the opposite side of the support plate 32 in the vertical direction diametrically opposite the material reinforcement 36, an extension 38 extending radially outwards from the plane of the support plate 32 is provided, which in particular determines the characteristic appearance of the letter "Ω". Also, this extension 38 is provided with two continuous longitudinal slots 38 a, which in plan view, in each case the shape of a lying, but have in the circumferential direction of the support plate 32 slightly tilted oval and serve to attach components of the brake unit 80. The longitudinal extension of the two longitudinal slots 38a in the circumferential direction of the support plate 32 is greater than that of the two oval through openings 36a of the material reinforcement 36. Like the two through openings 36a of the material reinforcement 36, the two longitudinal slots 38a of the extension 38 are on both sides of the vertically extending and through the center the support plate 32 going, not shown symmetry line of the support plate 32 arranged symmetrically.

In addition, a further through-view opening 38b which is circular in plan view is provided on the extension 38, the center of which lies on the above-mentioned, vertically extending symmetry line and which is arranged between the two longitudinal slots 38a.

It should also be noted that between the central passage opening 34 and the extension 38, a further passage opening 39 is arranged. This is spaced both to the central through-hole 34 and to the extension 38, but arranged closer to the central passage opening 34. This further passage opening 39 has at least approximately the shape of a lying keyhole for a two-sided beard key and is used for attachment of control and / or monitoring elements, such as light barriers. These may be used, for example, to detect the direction of rotation of the label roll, the speed of rotation of the label roll, the diameter reduction of the label roll, and so on.

The tension compensation device 40 initially contains a housing 42, which may be made, for example, from die-cast aluminum or cast steel. In plan view, the housing 42 has the shape of a rhombus, in particular the shape of a symmetrical to the longer of its two diagonal dragon quadrangle with rounded corners. The below the shorter of the two intersecting at an angle of 90 ° diagonal, ie the horizontal extending diagonal lying, isosceles triangle of the housing 42 has a greater height than the above this diagonal lying, isosceles triangle.

Furthermore, the housing 42 on its front side and on its rear side each have a recess 44, 46, which are each enclosed by an at least approximately perpendicularly protruding from the plane of the housing 42 edge 42 a. The first recess 44 located on the front side of the housing 42, except for the edge 42a, occupies the entire area of the upper isosceles triangle of the kite quadrangular housing 42 and serves for receiving components or assemblies of the rotary axis device 30 and the brake unit 80, such as this will be explained in more detail below. In addition, the recess 44 extends beyond the shorter of the two diagonals of the quadrangle of the kite, which intersect at an angle of 90 °, into the region of the lower isosceles triangle.

The recess 44 is bounded by a substantially horizontally oriented partition wall 42b. How out Fig. 2 it can be seen, the partition wall 42b of one of the two opposite edges 42a of the housing 42 initially runs horizontally, then in an unspecified circular arc segment, which extends downwards, and in turn ends in a horizontally oriented, also unspecified section of Partition wall 42b. The circular arc segment is arranged between the two horizontally extending sections of the dividing wall 42b symmetrically to the vertically extending axis of symmetry of the kite quadrangular housing 42. Following down to the partition wall 42b, the housing 42 transitions from the height of the partition wall 42b into an at least approximately planar surface 42c, which forms the bottom of the second recess 46 located on the rear side of the housing 42.

The second recess 46, which is provided at the rear of the housing 42, serves to accommodate various components or assemblies of the power unit 60, as will be explained in more detail below. She takes up the edge 42a and that part of the first recess 44, which extends beyond the shorter of the two intersecting at an angle of 90 ° diagonal of the dragon quadrangle, the area of the lower isosceles triangle of the kite quadrangular housing 42 a. At the top, the second recess 46 is bounded by the partition wall 42b. Thereafter, the housing 42 extends from the height of the partition wall 42b in an upwardly extending, the entire surface of the upper isosceles triangle of the krakchenviereckförmigen housing 42 engaging and at least approximately planar surface 42d over the bottom of the first, on the Front side of the housing 42 located recess 44 forms.

The tension compensation device 40 further has a circular through-hole 48 in plan view, the center of which is arranged on the vertically extending axis of symmetry of the kite quadrangular housing 42, spaced below the intersection of the diagonals of the quadrangle intersecting at an angle of 90 °. Through the passage opening 48, the axis of rotation of the rotary axis device 30 is guided concentrically therethrough. How out Fig. 2 4, the through-hole 48 has a left-hand edge 48a protruding from the plane of the recess 44 and integrally connected to the housing 42. On this edge 48a of the passage opening 48, as will be explained in more detail below, the brake drum 82 of the brake unit 80 is placed. In the interior of the passage opening 48 can still, if this should prove necessary, a ball or roller bearings can be arranged, which allows the Zugspannungsausgleichseinrichtung 40 about the axis of rotation of the rotary axis device 30 and about the rotational and central longitudinal axis M of the rotary axis device 30th can easily rotate or swivel. In principle, there is the possibility that this bearing is also designed as a sliding bearing.

The first recess 44 has, above the passage opening 48, an at least approximately C-shaped slot 50 which is arranged to pass through the passage 48 at an angle of at least approximately encloses about 180 ° above this. The slot 50, the ends of which are rounded, is intended to provide components of the brake unit 80 with the necessary freedom of movement when pivoting the tension compensation device 40. In addition, through the slot 50 any existing cables, for example, be passed for the aforementioned light barriers.

Furthermore, the first recess 44 has a substantially vertically extending further slot 52 which is disposed above the passage opening 48 and also above the C-shaped slot 50 at a distance from the latter. This slot 52, which extends at least approximately along the vertical axis of symmetry of the housing 42 and is arranged in the region of an unspecified material reinforcement of the housing 2, serves to receive a guide element 94 of the brake unit 80 which will be explained in more detail below, which is used to actuate the brake unit 80 serves.

At the bottom corner of the kite quadrangular housing 42, the already mentioned above guide and guide roller 54 is arranged, which serves to guide the material or label carrier web. This roller 54, which is substantially perpendicular to the housing 42 from the plane of the surface 42c forward, based on Fig. 2 , protrudes, is rotatably mounted on an unspecified axis, which is fixedly connected to the housing 42, axially secure. Optionally, the roller 54 may be provided with a coating, such as rubber, which avoids damage to the label carrier web.

The power unit 60, which is arranged within the second recess 46, initially consists of a helical compression spring 62, which preferably has a progressively extending spring rate. The helical compression spring 62 is pushed onto a guide rod 64 whose outer diameter at least approximately corresponds to the inner diameter of the compression spring 62. Furthermore, the compression spring 62 is enclosed by a spring housing 66, so that in total a buckling of the helical compression spring 62 is reliably prevented. The spring bar 64 and the spring housing 66 are provided at their respective ends facing away from the compression spring 62 with a first and a second fastening element 64a, 66a of the power unit 60.

The first fastening element 64a, with which the helical compression spring 62 is supported on the housing 42 of the Zugspannungsausgleichseinrichtung 40 in the Abstütz- or force application point is formed by a pivot not designated in detail, which is located in the Fig. 2 extends substantially horizontally. The pivot is received in the second recess 46 in the region of the lowermost corner of the kite quadrangular housing 42 in a corresponding bore, which preferably coincides with the bore for the axis of the guide roller 54. Optionally, the axis of the guide roller 54 may be identical to the pivot. About the pivot of the first fastener 64a, the power unit 60 is pivotally mounted to the housing 42, that is, it can pivot in the plane of the second recess 46.

How out Fig. 4 can be removed, forms the central longitudinal axis of the power unit 60 with the in Fig. 4 vertically extending and the rotational and central longitudinal axis M intersecting line of symmetry or diagonal of the kierviereckförmigen housing 42 an angle. If a vectorial force decomposition of the force generated by the force unit 60 is performed at the tip of this angle or at the force application point, the result is, inter alia, a force component oriented at an angle of 90 ° to the vertically running diagonal of the housing 42. This force component calls on the support distance between the force application point of the power unit 60 and the rotational and central longitudinal axis M, which coincides with the vertically extending diagonal of the housing 42, a force acting on the Zugspannungsausgleichseinrichtung 40 torque about the rotational and central longitudinal axis M. Therefore, this force component is also referred to as the torque-force component of the power unit 60.

Furthermore, the angle between the in Fig. 4 vertically extending and the rotational and central longitudinal axis M intersecting symmetry line or diagonal the kite quadrangular housing 42 and the central longitudinal line of the power unit 60 during the pivoting movement of the Zugspannungsausgleichseinrichtung 40 change, in particular, viewed from the starting position of the Zugspannungsausgleichsrichtung 40, are smaller (see. Fig. 5b, 5d, 5f ). Thereby, in turn, the above-mentioned torque-force component of the force generated by the power unit 60 acting along the center line of the power unit 60 can be kept at least approximately constant even though the force generated by the power unit 60 increases due to the progressive spring rate. As a result, a deflection of this device 40 counteracting, at least approximately constant torque is generated over the entire pivoting range of the tension compensation device 40.

As already mentioned, the second fastening element 66a of the power unit 60 is provided at the free end of the spring housing 66. With this second fastening element 66a, the power unit 60 is articulated to a support unit 68 belonging to the power unit 60. The latter is formed by a disk, which has at least approximately the shape of a drop of water in the plan view. The disc 68, whose thickness is much smaller than its diameter and which may be made of steel, is provided with a centrally disposed passage opening 68 a, by means of which the disc 68 mounted on the axis of rotation of the rotary axis device 30 and thus concentric with the rotary and Center longitudinal axis M is arranged. The arrangement of the support unit 68 on the axis of rotation of the rotary axis device 30 is chosen so that the support unit 68 with respect to this both axially and radially fixed.

As in particular from Fig. 4 can be removed, the support unit 68 four concentrically arranged around the rotational and Zentrfiängsachse M openings 68b, by means of which the support unit 68 is attached to the non-illustrated housing of the labeling E or any other frame of that device to the device 10 according to the invention , rotatably attached. Since, as has already been explained above, the device 10 according to the invention can be arranged in any desired position, For example, the four passage openings 68b are always used in pairs only. When in the Fig. 4 shown alignment of the support unit 68, only the two through-holes 68 b, which are arranged lower left and upper right, used. If the power unit 60 in the recess 46 on the other side, based on Fig. 4 , arranged, the two other through openings 68 b, ie the in Fig. 4 used at the moment left upper and lower right through openings 68b.

Furthermore, the support unit 68 has the drop shape mitstaltenden extension 68c, which extends to the support unit 68 radially outward and which serves for articulation or for supporting the power unit 60 via the upper attachment member 66a at the pivot point 69. The point of articulation or force application point 69 is defined by the intersection of the central longitudinal line of a passage opening in the extension 68 c, in which a, not shown, pivotally connecting the fastening element 66 a to the support unit 68, with the plane of the support unit 68.

As already explained above, the force produced by the helical compression spring 62 whose vector or force direction extends along the central longitudinal line of the helical compression spring 62 can be decomposed into individual force components at the force application point 65 on the basis of a force parallelogram or force triangle. One of these components forms the torque-force component which causes a torque acting on the tension compensation device 40. As in particular from a comparison of Fig. 5b, 5d and 5f is removable, the angle between the changes in Fig. 4 vertically extending and the rotation and central longitudinal axis M intersecting symmetry line or diagonal of the krakarviereckförmigen housing 42 and the central longitudinal line of the power unit 60 during the pivoting movement of the Zugspannungsausgleichseinrichtung 40 in such a way that it is smaller. This is achieved in that the helical compression spring on the one hand at its one point of application of force on the guide roller 54 and thus on the longer diagonal of the kite quadrangular housing 42, which passes through the rotation and center longitudinal axis M, and on the other hand eccentrically supported on the extension 68c of the support unit at a distance from the rotational and central longitudinal axis M. During the pivotal movement of the tension compensation device 40 and the housing 42, the force application point 65 remains stationary, whereas the force application point moves on a trajectory. At the same time, as is clear from a comparison of Fig. 5b, 5d, 5f shows the angle between the existing between the rotational and central longitudinal axis M and the force application point radius line and the central longitudinal line of the helical compression spring 62 larger. Despite increasing compressive force due to the increasing immersion of the progressive rate helical compression spring 62, this maintains the torque component of force which creates the torque applied to the housing 42 and which results from the vectorial decomposition of the compressive force generated by the helical compression spring 62.

Thus, if the device 10 according to the invention or the housing 42 from the in Fig. 1 shown starting position by acting on the web as a result of the conveying drive of the pressure / dispensing unit DS tensile force in Fig. 1 deflected to the right, as a result of this pivotal movement of the housing 42, the helical compression spring 62 is compressed. As a result, the helical compression spring 62 exerts a pressure force on the support unit 68 on the tension compensation device 40, which counteracts the torque of the pivoting movement of the housing 42 from its initial position. At the same time, as explained above, the angle between the central longitudinal line of the power unit 60 and that in FIG Fig. 4 In other words, the resulting torque over the entire movement or pivoting range of the housing 42 remains at least approximately constant, so that the tension exerted on the material web tension is also at least approximately constant.

The device 10 according to the invention further has a brake unit 80, which is arranged in the first recess 44 of the housing 42. The Brake unit 80 initially has a brake drum 82, which is arranged concentrically to and rotatable on the axis of rotation of the rotary axis device 30. There is a rotary connection between the brake drum 82 and the tension compensation device 40 or its housing 42, so that when the housing 42 is rotated or pivoted, the brake drum 82 is also rotated. How out Fig. 2 it can be seen, the brake drum 82 has a sufficiently wide, cylindrical side peripheral surface 82a, which serves as an engagement surface or mating surface for the two brake shoes 84 of the brake unit 80 which will be explained in more detail below.

The brake unit 80 further has the already mentioned brake shoes 84, which are arranged symmetrically to the brake drum 82 and thus symmetrically to the rotational and central longitudinal axis M of the device 10 according to the invention or the rotary axis device 30. The brake shoes 84 have the usual outer contour, ie they have the shape of an arc segment which extends over at least approximately 180 °. At their side facing the brake drum 82, they are each provided with a brake pad 84a. At their lower ends 84b they are pivotally articulated by means of suitable head bolts 85 on the oval passage openings 36a to the support plate 32 of the rotary axle 30 pivotally. At their upper ends 84 c, they are guided by means of likewise suitable, unspecified head bolts in the two longitudinal slots 38 a of the support plate 32. This makes it possible that the two brake shoes 84 can each be pivoted about its two lower axes of rotation in a radially outward direction, relative to the brake drum 82, so that the brake unit 80 from the braking position in which the brake shoes 84 fixed to the abut cylindrical outer peripheral surface 82a of the brake drum 82, in a release position in which the two brake shoes 84 spaced from the cylindrical peripheral surface 82a of the brake drum 82, can be moved. In the release position, the brake unit 80 exerts no braking action on the brake drum 82 and thus on the tension compensation device 40 or the entire device 10 according to the invention.

The two brake shoes 84 are biased by a tension spring 86, which is connected at the upper ends 84c of the brake shoes 84 with these in each case in the braking position. To move the brake shoes 84 reversibly out of the braking position into the release position, a sliding block 88 is provided between the two upper ends 84c of the brake shoes 84, which is provided with cam surfaces 88a on its sides facing the brake shoes 84. The cam surfaces 88a come into contact with two ball bearings 90, which are on the guide pins, by means of which the brake shoes 84 are guided in the longitudinal slots 38a of the support plate 32, plugged and axially secured there. How out Fig. 2 can be removed, the ball bearings 90 are inserted into a respective slot in the upper end 84c of the brake shoes 84. The unspecified outer bearing rings of the ball bearings 90 form the mating surfaces to the cam surfaces 88a of the sliding block 88 and can roll on this.

The sliding block 88 has in plan view, ie in the view from the front the shape of a parallelogram, the corners are rounded. Furthermore, the sliding block 88 with a head pivot 91 which is rotatably inserted in the passage opening 38b of the support plate 32b, rotatably and axially fixedly connected. The sliding block 88 can from the in Fig. 2 shown braking position in a in the Fig. 5c shown release position can be pivoted by approximately 90 °.

For pivoting the sliding block 88, a lever 92 is provided, which is rotatably connected in its lower end 92a with the sliding block 88 and has a longitudinal slot 92b at its upper end. In this longitudinal slot 92 engages a guide block 94, which in turn can be positioned in the longitudinal slot 52 in the upper recess 44 of the housing 42, thereby changing the switching point of the brake unit 80 can. If the housing 42 or the Zugspannungsausgieichseinrichtung 40 is pivoted, the lever 92 is also pivoted about the formed by the guide block 94 and the lever 92 actuating connection about its axis of rotation, which in turn the sliding block 88 is pivoted. As a result, the cam surfaces 88a of the sliding block 88 come into contact with the ball bearings 90. Due to the parallelogram configuration of the sliding block 88 upon further pivoting of the housing 42, the two upper ends 84c of the brake shoes 84 pressed apart so that releases the brake. When the housing 42 returns to its original position, the sliding block 88 in turn rotates back into its starting position so that the brake shoes 84 return to their initial position, ie the braking position, under the action of the tension spring 86.

Finally, it should be noted that the Zugspannungsausgleichsseinrichtung 40 and the housing 42 and the components housed therein or assemblies are arranged to each other and set in a weight relationship that the Zugspannungsausgleichseinrichtung 40 with respect to the Drehund center longitudinal axis M is almost neutral in weight. In other words, the tension compensation device 40 is independent of its rotational position in a stable equilibrium to the rotational and central longitudinal axis M and thus at rest. As a result, the device 10 according to the invention can be installed in any position.

• In den Figuren 5a bis 5f sind jeweils die Zugspannungsausgleichseinrichtung 40 in Vorder- und in Rückansicht wiedergegeben, wobei jeweils die Fig. 5a, 5b und 5c, 5d und 5e, 5f zwei zueinander gehörende Paare bilden, d.h. in den Figuren 5a, 5b wird die Zugspannungsausgleichseinrichtung 40 von der Vorder- und Rückseite in der gleichen Stellung wiedergegeben. Gleiches gilt für die Figuren 5c, 5d und 5e, 5f. Weiterhin sind zwischen den jeweiligen Figurenpaaren 5a, 5b und 5c, 5d und 5e, 5f Detailvergrößerungen wiedergeben, die mit I. bis III. bezeichnet sind.

The operation of the device 10 according to the invention is explained below with reference to the drawing figures 5a to 5f:

• In the FIGS. 5a to 5f each of the Zugspannungsausgleichseinrichtung 40 are shown in front and in rear view, wherein each of the Fig. 5a, 5b and 5c, 5d and 5e, 5f form two pairs belonging to each other, ie in the FIGS. 5a, 5b the tension compensation device 40 is reproduced from the front and back in the same position. The same applies to the FIGS. 5c, 5d and 5e, 5 f. Furthermore, between the respective pair of figures 5a, 5b and 5c, 5d and 5e, 5f detail enlargements reproduce that with I. to III. are designated.

In the FIGS. 5a, 5b the device 10 according to the invention or the tension compensation device 40 is shown in its initial position. In this context, it should be noted that this starting position in its rotational angle position not with the in Fig. 1 shown starting position of the invention Device 10 and the Zugspannungsausgleichseinrichtung 40 matches, but this has no effect on the function.

The starting position takes the device 10 according to the invention in particular when the material web is not conveyed and the device E, on which the device 10 according to the invention is used, is not in operation. The brake unit 80 is found in its braking position, as shown in detail 1.

If now the device on which the device 10 according to the invention is arranged, for example, the labeling device E is put into operation, unspecified drive rollers of the printing / dispensing unit DS remove the label carrier from the unwinding unit 20. In this case, the label carrier web moves on the left side around the guide roller 54 of the tension compensation device 40. As a result of the train applied to the material web by the drive rollers of the printing / dispensing unit DS, the tension compensation device 40 is simultaneously pivoted to the left (or to the right in FIG Fig. 2 ), as it is in the Fig. 5c, 5d is shown. In this case, the power unit 60 is actuated in such a manner that the compression spring 62 is compressed. This is done by the fact that by the pivoting of the Zugspannungsausgleichseinrichtung 40 of the force application point, as shown in Fig. 5d shown is moved to the right. Since the Schraubenduckfeder 62 can not escape, since it is connected at its upper end 66a with the stationary support unit 68, the helical compression spring 62 must dive. As a result, the force acting on the force application point 65 torque force component is caused, which exerts a torque on the Zugspannungsausgleichseinrichtung 40 over the support distance between the force application point and the rotational and central longitudinal axis M, which counteracts the deflection of the device 40.

Furthermore, the lever 92 is pivoted from its initial position in which it is vertically aligned, to the left, since the housing 42 of the Zugspannungsausgleichseinrichtung 40 is also pivoted to the left. In turn, since the sliding block 88 or its unspecified axis of rotation stationary remains, the lever 92 pivots, causing the sliding block 88 starts to rotate, so that in turn the brake shoes 84 move out of its braking position, as shown, inter alia, in the detail II.

With further increase of the train, the Zugspannungsausgleichseinrichtung 40 in the in the FIGS. 5e, 5f pivot position shown. Here, the brake unit 80, as shown in detail III, fully open, ie the brake shoes 84 are completely lifted from the cylindrical outer peripheral surface 82a of the brake drum 80. At the same time, the tension compensation device 40 has rotated further, whereby, as already stated above, the helical compression spring 62 is further compressed, since it can not escape due to the fixed fixation at the upper end 66a. In this position, the helical compression spring 62 exerts the greatest compressive force on the tension compensation device 40 or the device 10 according to the invention. Due to the fact that the angle between the central longitudinal line of the power unit 60 and the support distance or the longer diagonal of the housing 42 is reduced, or the angle between the center longitudinal line of the power unit 60 and the distance between the rotational and central longitudinal axis M and the Power application point 69 increases, but is the torque over that in the Fig. 5a, 5b as well as the Fig. 5c, 5d the same situation. Overall, therefore, a constant torque is exerted on the device 10 according to the invention.

If the conveying process for the material web interrupted, in particular no tensile force exerted on the web, the components return in response to the action of the helical compression spring 62 and the tension spring 86 in their initial position.

Claims (15)

1. Apparatus for maintaining a constant tension on a web of material, in particular on a label web used in a labelling machine (E), comprising a stationary rotary axle device (30) with a geometric rotational axis (M) and a tension compensation device (40) rotatable from a starting position about said rotational axis (M) of said rotary axle device (30), said tension compensation device (40) comprising a force unit (60) which exerts a force on the tension compensation device (40) that counteracts the rotational movement of the tension compensation device (40) from the starting position,
   characterized in that the force applied by the force unit (60) is a linear force acting on the tension compensation device (40) at a force application point with a radial spacing to the rotational axis (M) of the rotary axle device (30), and that simultaneously the geometric rotational axis (M) is a rotational axis for a unwinding unit (20).
2. Apparatus according to claim 1,
   characterized in that the force unit (60) is pivotable at the force application point relative to the tension compensation device (40).
3. Apparatus according to claim 1 or 2,
   characterized in that the angle between the line of force of the linearly acting force produced by the force unit (60), and the radial spacing between the rotational axis (M) and the force application point can be modified.
4. Apparatus according to anyone of the claims 1 to 3,
   characterized in that the size of the component of the force produced by the force unit (60), and which causes a torque to act on the tension compensation device (40) by means of the radial spacing between the rotational axis (M) of the rotary axle device (30) and the force application point of the tension compensation device (40), remains constant while the tension compensation device (40) is rotating.
5. Apparatus according to anyone of the claims 1 to 4,
   characterized in that the size of the force produced by the force unit (60) changes at least section by section along the path of rotational movement of the tension compensation device (40).
6. Apparatus according to anyone of the claims 1 to 5,
   characterized in that the tension compensation device (40) comprises a stationary attachment unit (68) on which an attachment point (69) for the force unit (60) is provided eccentrically to the rotational axis (M) of the rotary axle device (30).
7. Apparatus according to anyone of the claims 1 to 6,
   characterized in that there is also provided at least one unwinding unit (20) which is held on the rotary axle device (30) such that said unwinding unit is rotatable about the rotational axis (M) of said device.
8. Apparatus according anyone of the claims 1 to 7,
   characterized in that a stationary brake unit (80) is provided whose breaking power preferably acts upon an unwinding unit (24).
9. Apparatus according to claim 8,
   characterized in that the brake unit (80) is in its braking position when the tension compensation device (40) is in its starting position.
10. Apparatus according to claim 8 or 9,
    characterized in that the brake unit (80) is reversibly movable from its brake application position into its release position by means of at least one actuating element (88) connected for transmission of motion to the tension compensation device (40).
11. Apparatus according to anyone of the claims 8 to 10,
    characterized in that the brake unit (80) can be released from its brake application position when the rotational movement of the tension compensation device (40) begins.
12. Apparatus according to anyone of the claims 8 to 11,
    characterized in that the brake unit (80) is biased into its brake application position by means of at least one biasing element (86).
13. Apparatus according to anyone of the claims 8 to 12,
    characterized in that the brake unit (80) is formed by a shoe-type brake (84) of which at least one brake shoe (84) is rigidly connected to the rotary axle device (30), wherein the brake shoe (84) preferably acting upon a brake drum (82) connected non-rotatably to the unwinding unit (20).
14. Apparatus according to anyone of the claims 1 to 13,
    characterized in that the tension compensation device (40) includes a housing (42) which at least partially encloses components of the rotary axle device (30).
15. Apparatus according to anyone of the claims 1 to 14,
    characterized in that the weight distribution of the tension compensation device (40) is symmetrical with respect to the rotational axis (M) of the rotary axle device (30).

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