Pressing device for pressing on edge tapes

Description

[0001] The invention relates to a pressing device according to the preamble of claim 1. Such a pressing device is known from document DE 30 39 230 A1.

[0002] Pressing devices of the known type are used to press coating material, preferably edgebanding, onto the narrow sides of plate-shaped workpieces. The edgebanding or workpieces are prepared beforehand so that the edgebanding can adhere to the narrow side of the workpiece. The edgebanding is fed to the narrow side of the workpiece, and by engaging at least one pressure roller, the edgebanding is pressed against the narrow side of the workpiece. Typically, the pressure rollers used are rotatably mounted on a bearing section and adjustable relative to it via a suitable actuator. This adjustment is necessary to maintain or change, for example, the pressure force or the position of the pressure roller relative to the workpiece, with which the edgebanding is pressed against the workpiece, within a predetermined range. The pressure roller thus "scans" the surface, and this scanning can be adjusted if necessary.

[0003] For sensing a pressure roller, the smoothest possible sensing behavior is desirable. Therefore, a linear guide is unsuitable at this point, as it results in higher breakaway forces and inertia. A non-linear movement, such as a circular path, thus provides a smoother sensing behavior. Often, a rocker arm is used for this purpose, which positions the pressure roller relative to the bearing section, thereby enabling the appropriate sensing movement.

[0004] This means that the mechanism necessary for receiving and storing the pressure roller must be housed in the installation space where the rocker arm is articulated to the bearing section, i.e., where the pivot point is located around which the rocker arm with the pressure roller mounted on it rotates.

[0005] The object of the present invention is therefore to create a pressure device of the type mentioned at the outset that eliminates these disadvantages in terms of installation space.

[0006] This problem is solved by a pressing device with the features of claim 1. Advantageous embodiments are found in the dependent claims.

[0007] The pressure device according to the invention for pressing edge banding onto the narrow sides of flat workpieces made of wood or wood substitutes comprises a bearing section and at least one rotatably mounted first pressure roller. The latter is coupled to the bearing section via a lever. The first pressure roller can be disengaged relative to the bearing section by pivoting the lever, particularly by means of an associated actuator. According to the invention, the first pressure roller is mounted on a push section, which is preferably a push rod. The push section is coupled to the bearing section via the at least one lever such that the lever, the push section, and the bearing section form a multi-joint, in particular a three-joint, linkage.

[0008] A multi-joint mechanism consisting of a lever and a pushrod allows the guidance of the pressure roller's axis of rotation to be modified when probing against the edge band or workpiece. This results in a less pronounced movement path when the pressure roller is advanced or retracted compared to the rocker arm described above. This saves installation space without sacrificing the advantages of the smoother probing action of a rocker arm.

[0009] According to a preferred embodiment of the present invention, the thrust section is coupled to the bearing section via at least one lever and an additional second lever. The lever, the thrust section, and the base section form a four-bar linkage. This embodiment has the particular advantage that the angular position of the thrust section does not change during the probing or positioning process. Therefore, no special guide for the thrust section is required that allows pivoting movements.

[0010] Preferably, the pressure device according to the invention can have at least one rotatably mounted additional pressure roller, which can then be used as a secondary pressure roller alongside the first pressure roller designed as the main pressure roller. Depending on the intended use, the additional pressure roller or rollers preferably have the same or a smaller diameter than the first pressure roller.

[0011] Naturally, each additional pressure roller can be coupled to the bearing section, particularly via a lever. Each additional pressure roller can be disengaged from the bearing section by a corresponding actuator, allowing the pressure to be adjusted accordingly for the other pressure rollers as well.

[0012] The multi-link arrangement according to the invention makes it possible for the movement of the push section to pivot the axis of rotation of the first pressure roller approximately about a virtual pivot axis. "Approximately" here means that the spatial position of the virtual pivot axis does not have to be absolutely fixed, but rather that movements of the virtual pivot axis are possible. The virtual pivot axis is the pivot axis to which a rocker arm would be articulated if it were directly connected to the pressure roller. The multi-link arrangement makes it possible to position the virtual pivot axis at points that would not normally be available for mounting a rocker arm; for example, such a virtual pivot axis could be located in an area where the workpiece is normally moved past the pressure device. Depending on the position of this virtual pivot axis, more or less installation space can be saved.

[0013] According to the invention, a coordinate system originating on the axis of rotation of the first pressure roller divides the plane of motion of the pressure roller into four quadrants. Preferably, the first axis of the coordinate system is parallel to the plane of the narrow side of the workpiece or its feed direction, and the second axis of the coordinate system runs at an angle, particularly a right angle, to it. The first axis then has a side facing the workpiece and a side facing away from the workpiece. This coordinate system can be divided into four quadrants, which are defined by the two coordinate axes.The quadrant located to the right of the second coordinate axis on the workpiece side is defined as the first quadrant, the quadrant located to the left of the second coordinate axis on the workpiece side is defined as the second quadrant, the left quadrant located on the side facing away from the workpiece is defined as the third quadrant, and the right quadrant located on the side facing away from the workpiece is defined as the fourth quadrant.

[0014] Installation space can be reduced, in particular, if the virtual pivot axis is located in the second or fourth quadrant. It is therefore preferred that the at least one lever or the plurality of levers on the bearing section and the push element are articulated such that the virtual pivot axis of the first pressure roller lies in the second or fourth quadrant. Arranging the virtual pivot axis in one of these two quadrants has the advantage that the probing movement performed by the first pressure roller has a motion component in the feed direction of the workpiece. In contrast, a virtual pivot axis in quadrants one and three would have the disadvantage that the motion path of the pressure roller would have at least one motion component running against the feed direction of the workpiece.

[0015] The invention is described below with reference to the Figures 1 to 5 A more detailed schematic explanation is provided. Figure 1shows a movement scheme of the first pressure roller as part of the pressure device according to the invention. Figure 2 Figure 1 shows a first embodiment of the pressure device according to the invention in a schematic representation in a first variant. Figure 3A The first embodiment according to the invention is shown in a second variant and in a first keying position. Figure 3B shows the in Figure 3A The illustrated embodiment in a further keying position. Figure 4 shows a second embodiment of the invention in a first variant. Figure 5 The second embodiment according to the invention is shown in a second variant.

[0016] In the Figure 1The schematic arrangement shown indicates a pressure device 1, which in the example shown comprises a first pressure roller 20 rotatably mounted about an axis A1, and preferably further pressure rollers 21, 22, each rotatably mounted about axes A2 and A3, respectively. A workpiece 3, which is provided as a plate-shaped workpiece made of wood or wood substitutes, can be guided past the pressure device 1 in a feed direction P. An edge band (not shown) is pressed against the narrow side of the workpiece 3. The plane of the narrow side of the workpiece 3 is indicated in the example shown by the dashed line E. According to the invention, the axis of rotation A1 of the first pressure roller 20 forms the origin of a coordinate system, which comprises a first axis X, which preferably runs parallel to the feed direction P of the workpiece 3, and a second axis Y, which is preferably perpendicular to the axis X.This coordinate system divides space into four quadrants, I-IV. A distinction is made between the side of the X-axis facing workpiece 3 (the workpiece side) and the side of the X-axis facing away from workpiece 3. The first quadrant, I, is located on the workpiece side to the right of the Y-axis, while the second quadrant, II, is located on the workpiece side to the left of the Y-axis. Similarly, the third quadrant, III, is located on the side of the X-axis facing away from the workpiece and to the left of the Y-axis, while the fourth quadrant, IV, is located on the side of the X-axis facing away from the workpiece and to the right of the Y-axis.

[0017] Arrows PI to PIV denote possible directions of movement of the axis of rotation A1 of the first pressure roller, which can be realized with the pressure device 1 according to the invention. The arrangement of lever(s) and a push section according to the invention allows virtual pivot points to be created, which enable these different paths of movement.

[0018] This should now be implemented at the in the Figures 2 to 5 The illustrated examples will be explained.

[0019] In Figure 2 The first pressure roller 20 is rotatably mounted on a push rod 40c, shown here as a push section, about the axis A1. The push rod 40c is rotatably mounted on a bearing arrangement 2 (not shown) by means of a pivot bearing 26 and is slidably mounted in a linear guide 25. In the example shown, the Figure 2The thrust section 40c is arranged on a linear guide 25 that pivots parallel to the axis A1 on a pivot bearing 26. Furthermore, the thrust section 40c is articulated to a lever 40b at point 28, which in turn is pivotally connected to the bearing arrangement 2 via a pivot bearing 27. In the illustrated example, the pivot point 28 of the lever 40b on the thrust section 40c lies between the pivoting linear guide 25 and the axis A1. Consequently, pivoting the lever 40b causes the thrust section 40c to necessarily follow this movement, thus shifting within the linear guide 25 and also pivoting via the pivot bearing 26. This shifts the axis A1 along arrow P II. This approximates a pivoting movement of the axis A1 by means of a rocker arm that pivots about a fixed or movable virtual pivot point VA. According to the definition above, this virtual pivot point lies in quadrant II.

[0020] Figure 3A shows an embodiment in which, in contrast to the embodiment of the Figure 2 The pivot bearing 27 for the lever 40b is located on the right side of the Y-axis. As a result, pivoting the lever 40b causes the axis A1 of the pressure roller 20 to move along the path of motion P IV. This corresponds to a virtual pivot point VA located in quadrant IV. This is in Figure 3B To illustrate, pivoting the lever 40b about the pivot bearing 27 displaces the thrust section 40c and pivots it by an angle α to the original position. Figure 3AThe position shown is indicated by the dashed line L. This shifts the axis of rotation A1 of the pressure roller 20 on the track P IV, which corresponds at least approximately to a rotation of axis A1 around a virtual pivot point VA located in quadrant IV. As a result, in the example shown, the pressure roller 20 is shifted in the Y direction relative to the other pressure rollers 21 and 22.

[0021] This displacement then allows for a corresponding adjustment or sensing of the pressure roller 20 relative to the workpiece 3 with the aid of a corresponding machine control (not shown).

[0022] Two alternative embodiments are described in the Figures 4 and 5 depicted.

[0023] In contrast to the embodiments described so far, the thrust section 40c and lever 40b do not form a three-joint mechanism. Instead, a further lever 40a is provided, which, together with the lever 40b and the thrust section 40c already described above, forms a four-joint mechanism. The lever 40b is pivotally mounted on the bearing section 2 via a first pivot bearing 27b, while the second lever 40a is pivotally mounted on the bearing section 2 via a corresponding pivot bearing 27a. The respective other ends of the two levers 40a and 40b are hinged to the thrust section 40c at different locations 28a and 28b, respectively. In this embodiment, the pivot bearings 27b and 27a are located in Figure 4 to the left of the Y-axis, while in Figure 5 They lie to the right of the Y-axis. In the example shown, levers 40b and 40a do not cross.

[0024] The illustrated four-bar linkage arrangement results in the thrust section 40c not performing a pivoting movement when both levers 40a and 40b, which are preferably arranged parallel to each other, are pivoted, provided the two levers are arranged parallel, but merely exerting a parallel displacement. In this way, the arrangement according to Figure 4 The motion path P II is realized, which corresponds to a virtual axis of rotation VA in the second quadrant. In the arrangement according to Figure 5 The axis of rotation A1 can be pivoted about the virtual pivot point VA, which corresponds to a path of motion P IV. The virtual pivot point VA then lies in the fourth quadrant.

[0025] All arrangements shown create virtual axes of rotation VA for the pressure roller 20 or the axis of rotation A1 thereof, with which the movement of the pressure roller 20 for the delivery or sensing process can be optimized without requiring too much installation space.

Claims

1. Pressing device (1) for pressing edge bands against the narrow sides of platetype workpieces (3) of wood or wood substitutes, comprising a bearing portion (2) and at least one rotatably mounted first pressing roller (20) wherein the first pressing roller (20) is coupled to the bearing portion (2) by way of a lever (40a, 40b), wherein the first pressing roller (20) can be drawn out relative to the bearing portion (2), in particular by an associated servo drive, by pivoting the lever (40a, 40b), wherein the first pressing roller (20) is mounted on a push portion (40c), in particular a push rod, which is coupled by the at least one lever (40a) to the bearing portion (2) so that the lever (40a, 40b), the push portion (40c) and the bearing portion (2) form a multi-articulated joint, in particular a triple joint, characterised in that the movement of the push portion (40c) pivots the axis of rotation (A1) of the first pressing roller (20), in particular approximately, about a virtual pivotal axis (VA) wherein a system of coordinates with its origin in the axis of rotation (A1) of the first pressing roller (20) divides the plane of movement of the pressing roller into four quadrants (I-IV).

2. Pressing device (1) according to Claim 1 characterised in that the push portion (40c) is coupled to the bearing portion (2) by way of the at least one lever (40b) and an additional second lever (40a) so that the levers (40a, 40b), the push portion (40c), and the base portion (2) form a four-point articulated joint.

3. Pressing device (1) according to Claim 1 characterised in that it comprises at least one rotatably mounted additional pressing roller (21, 22).

4. Pressing device (1) according to Claim 3 characterised in that the or each additional pressing roller (21, 22) is coupled in particular by a lever to the bearing portion (2) wherein the or each additional pressing roller (21, 22) can be drawn out relative to the bearing portion (2) by the associated servo drive.

5. Pressing device (1) according to Claim 3 or 4 characterised in that the or each additional pressing roller (21, 22) has the same or smaller diameter than the first pressing roller (20).

6. Pressing device (1) according to one of the preceding claims characterised in that the first axis of the system of coordinates runs parallel to the plane (E) of the narrow side of the workpiece (3) or its feed direction (X) and the second axis (Y) of the system of coordinates runs at an angle, in particular at a right angle, thereto wherein the first axis (X) has a workpiece side facing the workpiece (3) and a side facing away from the workpiece.

7. Pressing device (1) according to Claim 6 characterised in that the system of coordinates is defined by the coordinate axes (X,Y) and is divided into quadrants (I-IV) wherein the quadrant placed on the workpiece side to the right of the second coordinate axis (Y) is defined as the first quadrant (I), the quadrant placed on the workpiece side to the left of the second coordinate axis (Y) is defined as the second quadrant (II), the quadrant placed to the left on the side facing away from the workpiece is defined as the third quadrant (III), and the quadrant placed to the right on the side facing away from the workpiece is defined as the fourth quadrant (IV).

8. Pressing device according to Claim 7 characterised in that the at least one lever (40a) or the plurality of levers (40a, 40b) is / are attached for articulated movement to the bearing portion (2) and the push element (40c) so that the virtual pivotal axis (VA) of the first pressing roller (20) lies in the second quadrant (II) or in the fourth quadrant (IV).