Rotary Frame Construction for Web Transport Control Devices

Abstract

A rotary frame construction for web transport control devices, includes a carrier frame and a rotary frame in parallel therewith and carrying input and output rollers for a web and pivotably mounted on the carrier frame about a rotation center defined by control surfaces of one frame, the control surfaces scanned by cam followers on the other frame, the frames held in parallel alignment by support rollers on one frame and run surfaces on the other frame, the frames pivotally connected with one another by a drive system, the control surfaces constituted by three control curves formed at outer edges of a cam plate rigidly held on one frame, two of the control curves located on one side of the cam plate and the third on the opposite side of the cam plate, and the other frame has three cam followers respectively associated with one of the control curves.

Claims

1. A rotary frame construction for web transport control devices, comprising: a carrier frame, a rotary frame which extends in parallel with the carrier frame and carries an input roller and an output roller for a web to be controlled, the rotary frame being pivotably mounted on the carrier frame by a bearing having a virtual rotation center that is defined by control surfaces of one of the carrier frame and the rotary frame, cam followers on the other of the frames for riding along the control surfaces, support rollers on one of the frames and associated run surfaces on the other frame for holding the frames in parallel alignment, a drive system, with the frames being connected with one another so as to be pivotable by means of the drive system, wherein the control surfaces are constituted by three control curves that are formed at outer edges of a cam plate that is rigidly held on one of the frames, with two of the control curves being located on one side of the cam plate and the third on an opposite side of the cam plate, and wherein the other of the frames has three said cam followers that are respectively associated with one of the control curves.

2. The rotary frame construction according to claim 1, wherein the cam plate forms part of the rotary frame and is enclosed by parts of the carrier frame which carries the cam followers that are configured as follower rolls.

3. The rotary frame construction according to claim 2, wherein the carrier frame has a base plate that extends in parallel with the cam plate and on which bearings for the follower rolls are arranged such that axes of rotation of the follower rolls are orthogonal to the base plate.

4. The rotary frame construction according to claim 3, further comprising a support plate carrying bearing axles for the follower rolls mounted on the base plate so as to rest flat on the base plate.

5. The rotary frame construction according to claim 3, further comprising brackets in which the support rollers are rotatably supported, arranged upright on one of the base plate and the support plate.

6. The rotary frame construction according to claim 2, wherein the rotary frame includes: two parallel side walls with projecting bearing brackets for the input roller and the output roller and a plate-shaped cross-bar that connects the side walls and on which the cam plate is supported via studs.

7. The rotary frame construction according to claim 6, wherein each of the support rollers is accommodated in a slot that is formed in the other of the frames and each slot has parallel edges that form run surfaces for the support rollers.

8. The rotary frame construction according to claim 7, further comprising at least one wall member that is trapezoidal in plan view and has legs that extend tangentially with respect to a circle around the virtual rotation center, the slots being formed in the legs of this wall member.

9. The rotary frame construction according to claim 8, comprising: two said trapezoidal wall members that are arranged such that base lines of the trapezoids are parallel to one another and the legs of the two wall members are symmetrically arranged and form different angles with the base line, and a total of four support rollers engaging in respective ones of the slots of the wall members.

10. The rotary frame construction according to claim 9, wherein one of the wall members forms the studs for holding the cam plate.

11. The rotary frame construction according to claim 5, wherein the brackets have pegs that engage in corresponding peg holes of: the base plate, the support plate, a plate-shaped cross-bar that connects two parallel side walls with projecting bearing brackets for the input roller and the output roller and on which the cam plate is supported and the cam plate, respectively.

12. The rotary frame construction according to claim 6, wherein the cam plate has projections that are in form-fitting engagement with recesses in the side walls of the rotary frame.

13. The rotary frame construction according to claim 1, wherein the drive system is self-arresting in at least one direction, and the frames are elastically biased against one another in the rotary direction in which the drive system is self-arresting.

14. The rotary frame construction according to claim 13, wherein the drive system is a linear drive that is connected to a lever, of the carrier frame and the rotary frame, respectively, by articulated joints, and one of a compression spring and a tension spring is held under tension between these levers.

15. The rotary frame construction according to claim 8, wherein the at least one wall member has pegs that engage in corresponding peg holes of: a base plate of the carrier frame, the support plate of the carrier frame, the cross-bar and the cam plate, respectively.

Description

[0019] An embodiment example will now be described in conjunction with the drawings, wherein:

[0020] FIG. 1 is a schematic top plan view of a rotary frame construction;

[0021] FIG. 2 shows the rotary frame construction with a slightly pivoted rotary frame;

[0022] FIG. 3 is a view of the rotary frame construction as seen in the direction of arrows III-III in FIG. 1;

[0023] FIG. 4 is an enlarged side view of the rotary frame construction as seen in the direction of arrows IV-IV in FIG. 1;

[0024] FIG. 5 is a plan view of a base plate of a carrier frame;

[0025] FIG. 6 is a top plan view of a support plate of the carrier frame;

[0026] FIG. 7 is the front view of the carrier frame;

[0027] FIGS. 8 and 9 are front views of two fastening members for fastening a cam plate to the rotary frame; and

[0028] FIG. 10 is a plan view of the cam plate.

[0029] FIG. 1 shows a top plan view of a rotary frame construction comprising a carrier frame 10 and a rotary frame 12 that are pivotable relative to one another about a virtual rotation center P. FIG. 2 shows the rotary frame construction with the rotary frame slightly pivoted. For ease of distinction, all parts that belong to the (stationary) carrier frame 10 have been shown in bolder lines than the parts that are movable with the rotary frame 12.

[0030] An input roller 14 and an output roller 16 are rotatably supported in the rotary frame 12, and a material web which has not been shown and the movement of which shall be steered by means of the rotary frame construction is threaded over the input and output rollers. For example, the material web may, in inverted U-thread, run upwards (in the direction towards the viewer in FIG. 1) to the input roller 14 where it is deflected in the horizontal direction so as to be passed-on to the output roller 16 where it is deflected again so that it will then move downwards.

[0031] The carrier frame 10 has a horizontal base plate 18 the greatest part of which is hidden by the rotary frame 12 in FIG. 1, so that only the left edge of the base plate 18 is visible. On the right side in FIG. 1, the base plate 18 forms a lever 20 that projects beyond the lateral edge of the rotary frame 12 and is connected to a bracket or a lever 24 of the rotary frame via an articulated linear drive 22. When the linear drive 22 draws the levers 20 and 24 together, the rotary frame 20 pivots about the vertical pivotal axis that passes through the rotation center P, as has been shown in FIG. 2. This pivotal axis forms a tangent to the input roller 14, so that the input roller and, therewith, the incoming material web does not make any lateral movement when the rotary frame 12 is rotated, whereas the output roller 16 and the outgoing material web are displaced in lateral direction.

[0032] The rotary frame 12 forms a gutter-shaped downwardly open casing 26 the top wall of which forms a cross-bar 28 for holding a cam plate 30 that is accommodated in the interior of the casing 26 and is connected to the cross-bar 28 by a wall member 32 that is trapezoidal in plan view. The edge of the cam plate 30 forms, on the bottom side in FIG. 1, two control curves 34 shaped as circular arcs and, on the top side, another control curve 36 shaped as a circular arc. The control curves 34 and 36 are centered on the virtual rotation center P. In order to illustrate the curvature of the control curves 34, 36 more clearly, FIG. 1 shows extended circular arc segments (continuous lines). Associated with each of the control curves 34, 36 is a follower roll 38 that is supported on the carrier frame 10 so as to be rotatable about a vertical axis. The three follower rolls 38 engage the edge of the cam plate 30 practically without play, so that this cam plate and, therewith, the entire rotary frame 12 can only perform a circular movement relative to the carrier frame about the virtual rotation center P.

[0033] Four brackets 40 that project vertically from the base plate and each support a support roller 42 have been welded onto the carrier frame 10. Two of these support rollers 42 are accommodated in slots 44 (FIG. 8) that extend horizontally in the legs of the trapezoidal wall member 32. These legs of the wall member 32 are angled such that they extend tangentially to an arc of a circle around the virtual rotation center P. If a downwardly directed force (weight) acts upon the rotary frame 12, then the top edges of the slots 44 are urged against the support rollers 42 so that the wall member 32 and, therewith, the entire rotary frame 12 are supported on the support rollers 42. When the rotary frame is pivoted, there is a relative movement between the support roller and the slot, and the support roller rolls along the top edge of the slot.

[0034] In the case that the rotary frame 20 is subject to an upwardly directed force, the lower edges of the slots 44 are urged against the support rollers 42, and in case of a pivotal movement, the support rollers will roll along these lower edges of the slots. The play of the support rollers 42 in the slots 44 is on the one hand so large that the support rollers can move with low friction and is on the other hand so small that the vertical movement of the wall member 32 relative to the support frame, as admitted by the play, remains within the admissible tolerances.

[0035] The casing 26 of the rotary frame 12 accommodates another wall member 46 that is trapezoidal in plan view and is fixed on the bottom side of the cross-bar 28, and slots 48 are formed in the angled legs of this wall member (FIG. 9). Two of the four support rollers 42 are accommodated in these slots of the wall member 46. The legs of this wall member are also angled such that they extend tangentially to an arc of a circle around the virtual rotation center P. The wall member 46 is therefore guided and supported with low play by the support rollers 42 in the same manner as the wall member 32. All in all, the engagement of the support rollers 42 in the slots 44, 48 prevents a vertical movement of the rotary frame relative to the carrier frame, and the rotary frame and the carrier frame are held in exact parallel alignment.

[0036] A holder 50 for one end of a tension spring 52 is mounted on the base plate 18 of the carrier frame and on the lever 20 formed by this base plate. The other end of the tension spring is anchored at the lever 24 of the rotary frame 12, so that a permanent tensioning force is produced that has the tendency to draw the levers 20 and 24 together and to rotate the rotary frame 12 counter-clockwise relative to the carrier frame 10. However, the linear drive 22 is self-arresting at least in the direction in which its length decreases, so that the torque exerted by the tension spring 52 does not actually cause a rotation of the rotary frame 12. However, the elastic bias that is caused by the spring 52 has the effect that any play in the bearing formed by the control curves 34, 36 and the follower rolls 38 as well as any play in the linear drive 22 and its articulated joints with the levers 20, 24 is eliminated.

[0037] When the machine of which the rotary frame construction described here forms part is operating, the lateral position of the material web is detected by means of a sensor, and the linear drive 22 is controlled by means of a controller such that the position of the material web is adjusted to a target value. In this feedback-control process, the linear drive 22 is alternatingly extended and retracted in order to rotate the rotary frame in the one direction or the other. The tension spring 52 assures that no hysteresis occurs in this control process because the spring will always hold all components of the system in which a certain play may occur at the same limit of the range of movement that is admitted by the play.

[0038] FIG. 3 shows the rotary frame construction in a front view. Welded on the base plate 18 of the carrier frame 10 is a support plate 54 on which the follower rolls 38 are rotatably supported. The contours of the base plate 18 and the support plate 54 have been shown separately in FIGS. 5 and 6. FIG. 6 also shows bearing holes or bearing axles 56 for the follower rolls 38. In FIG. 5, the positions of these bearings axles have been shown in phantom lines. The base plate 18 has recesses 58, 60 which accommodate the ends of the bearing axles.

[0039] The brackets 40 for the support rollers 42 are also welded to the support plate 54. In order to assure an exact positioning and safe immobilization of the brackets 40, these brackets are formed, on the edge facing the support plate 54, with pegs which have not been shown and which engage in corresponding peg holes of the support plate 54.

[0040] FIG. 7 shows the entire carrier frame in a front view. The wall member 32 with trapezoidal contour that forms the slots 44 for the support rollers 42 is visible in FIG. 3 and has been shown separately in FIG. 8. This wall member is also formed with projecting pegs at its top edge, the pegs engaging in corresponding peg holes (not shown) of the cross-bar 28.

[0041] FIG. 9 shows a front view of the wall member 46 forming the slots 48 for the two other support rollers 42. This wall member is also formed with pegs 64 at its top edge, for engagement into peg holes of the cross-bar 28.

[0042] In FIG. 3, the wall member 46 is largely obscured by the wall member 32 that is disposed in front thereof, so that what is visible are only downwardly projecting studs 66 (FIG. 9). These studs are formed at their bottom ends with pegs 68 for engagement in peg holes 70 of the cam plate 30 a plan view of which has been shown separately in FIG. 10. The cam plate 30 is welded to the pegs 68 and is thereby immobilized in its position in the rotary frame 12. For further stabilization, the cam plate 30 has projections 72 at both ends, these projections being in form-fitting engagement with corresponding recesses in side walls 74 of the casing 28, as can be seen in FIG. 3.

[0043] FIG. 4 shows the rotary frame construction in a side view. Of the carrier frame, only the base plate 18 is visible here. The side walls 74 of the casing 26 of the rotary frame are prolonged at both ends to form bearing brackets 76 for the input roller 14 and the output roller 16. These bearing brackets may have different shapes, depending upon the desired type of threading of the material web. FIG. 4 shows the configuration for inverted U-thread. In this configuration, the entire constructional height of the rotary frame construction is only slightly larger than the diameter of the input and output rollers 14, 16. Moreover, FIG. 4 shows one of the projections 72 of the cam plate that penetrate the side wall 74.