Patent Application
20050239623
The present invention refers to a device for aligning plate-like workpieces in a machine processing them, more particularly in a machine manufacturing packaging such as a folder-gluer.
Such a machine is commonly used for manufacturing, for example, cardboard boxes from plate-like workpieces also called box blanks. These plate-like workpieces generally result from the diecutting of a sheet or a web by another machine in a series of preceding operations. A folder-gluer generally comprises a succession of modules, each carrying out a determined operation so that the blanks, introduced at the machine entry, leaves in the shape of folded boxes ready to use. To this end, a folder-gluer generally comprises a feeder supplying the machine with box blanks from a pile of blanks. The conveying of these blanks into the various modules of the machine is carried out by a belt conveyor which, via friction, seizes the blanks, either between lower and upper belts or between lower belts and upper pressure rollers. Typically, the operations carried out in the machine are: the prebreaking of certain folding lines of the blank, the folding of certain parts, the gluing of the glue tabs, the pressing of the folded and glued blanks and their delivery at the end of the production line.
To achieve an accurate folding along the creasing lines provided for this purpose on each blank, it is necessary to correctly introduce these blanks into the machine and then to prevent any sliding during their transport. Thus, the first problem the skilled man is faced with is that of the introduction of these blanks into the machine. Effectively, it is essential that their position laterally as well as longitudinally is in perfect register with the previous folding members. Thus, the sequential feeding of the blanks into the machine is carried out from a pile from which the plate-like workpieces are drawn off one by one from the bottom of the pile. The blanks are driven forward by friction of the belts on each blank located in turn at the bottom of the pile whereas a front gauge in front of the pile defines a just sufficient space, between its lower edge and the plane of the conveyor, so that only one blank can there be introduced at the same time. The box blank in the course of introduction temporarily blocks the space between the lower end of the gauge and the surface of the belt conveyor in order to prevent departure of the next blank until the rear edge of the blank in the course of introduction has left the space under the gauge. Due to the fact that the frictional force between the blank at the bottom of the pile and the belts is much greater than that between two blanks, even the blanks located at the bottom of the pile, the introduction can be controlled perfectly. However, these friction forces naturally generate wear of the blanks causing cardboard dust which finally dirties the driving belts and can influence the adherence of the plate-like workpieces. According to the size of the box blanks, a plurality of belts may be arranged parallel to one another in order to ensure transport of the blanks. However, due to the dirt accumulation of these belts, an imbalance of the frictional forces between the plate-like workpiece and each of these belts is possible. These differences in the forces create a moment which, when applied on the blank, will tend to turn it in the horizontal plane and therefore to introduce it askew in an incorrect orientation.
Aligning devices are used to correct this problem, which force each badly introduced blank to align along a reference line in a correct orientation. This aligning operation is obviously carried out before the prebreaking of the blank folds. To carry out such an operation, it is known to use the drive of a belt placed slightly askew with respect to the longitudinal axis of the machine so as to force the blanks to align against a longitudinal reference edge. U.S. Pat. No. 3,519,266 describes a feed table equipped with an endless belt for driving sheets of paper or cardboard. The arrangement of this belt is such that it defines an acute angle between its orientation and the longitudinal edge of the machine. Owing to this oblique orientation, the sheets are driven, before leaving the feed table, towards a support rule parallel to the longitudinal edge of the machine. Thus, all the sheets can be aligned on the feed table along this support rule. In order to ensure a sufficient friction between the sheets and the belt, a plurality of pressure rollers are arranged along a bar placed above the driving belt. The whole is arranged in a carriage which is movable in the lateral direction so as to be adaptable to the various possible sheet sizes. The orientation of the belt can vary owing to the arrangement of a bearing supporting one of the end pulleys of the driving belt and swivelling around a vertical axis. The bar supporting the pressure rollers is also swivelling so that it can be oriented according to the same angle than that of the driving belt.
Swiss Patent CH 678,707 describes another device for aligning box blanks comprising a movable longitudinal guiding rail, a lower endless belt driven and supported by rollers, and a succession of upper rollers, each mounted swivelling vertically and horizontally so that it is not only possible to lower or raise each roller in order to adjust the pressure on the blank, but also to independently orient each of them in a chosen direction. Having numerous adjustment possibilities, this device has the drawback of being particularly expensive and complicated to realize. Moreover, due to the numerous adjustment possibilities, it can require the device be handled a relatively long time.
Another device for aligning box blanks is described in EP 610,791. In addition to a longitudinal guiding rail fixedly attached to a fixed part of the frame, this device comprises a lower conveyor mounted on a lower longitudinal bar and, in correspondence, an upper conveyor secured by adjusting means to an upper longitudinal bar. A bracket connects the lower longitudinal bar to the upper longitudinal bar so that the angular adjustment of the lower and upper conveyors can be carried out simultaneously. To this end, one of the ends of the lower longitudinal bar is mounted swivelling in the horizontal plane on a fixed part of the frame by means of a pivot with vertical axis. At the opposite end, a device comprising screws and threaded ring allows removing this end from the longitudinal guiding rail and hence to vary the angle of orientation of the pair of lower and upper conveyors with respect to the longitudinal reference axis.
The main problems of the previously described devices are on the one hand their production cost and on the other hand it is impossible to use them interchangeably on the left or on the right side of the machine. Effectively, according to the box type to be realized, the box blanks should sometimes be aligned on the left side of the machine rather than on the right side, in accordance with the position of the gluing tab of the blank. To enable this changeover, the machine should specifically be equipped with an aligning device designed for an alignment on the left side, for example, whereas in most cases, the alignment is made on the right side of the machine with respect to the traveling direction of the blanks. However, due to their design, currently known devices cannot be used for aligning blanks at choice on the left or the right side of the machine. In the device illustrated in EP 610,791, this impossibility is due to the fact that the pivot point is arranged beside a vertical base plate, at half height of that one, being used as fixed structure for the aligning device. Due to this fact, the lower conveyor can be removed only on one side from the vertical base plate and can thus align only on the right side or only on the left side according to its design. Effectively, it is precisely because of its design, namely the arrangement and the space requirement at the same time of its bearing structure, the return rollers and the path of the belt, that the aligner members of such an aligning device cannot be positioned angularly on one side or the other according to the needs.
The aim of the present invention is to overcome these main drawbacks by proposing an aligning device which is in particular more economic to manufacture, simpler to realize and which can be used indifferently for an alignment called on the right or on the left while only requiring a minimum of handling to realize such an inversion.
This aim is achieved owing to the present invention of a device for aligning plate-like workpieces traveling in a machine direction in a machine processing them, more particularly in a folder-gluer. The device comprises an upper aligner and a lower aligner. The lower aligner is equipped, on the one hand with a guiding member mounted on a lower guide, and on the other hand with a lower conveyor having at least one useful portion which is fixedly attached to an upper guide movable in the horizontal plane with respect to the lower guide. The lower and upper guides form a bearing element unit, which is weakened by an opening extending between the guides.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
The invention will be more clearly understood from the study of a preferred embodiment given by way of non-limitative example and illustrated by the accompanying drawings, in which:
a and 1b are perspective views of the aligning device of the present invention, respectively of an upper aligner member and a lower aligner member seen from the side opposite the operator's side.
a and 2b are views from the operator's side of
The pairs of
As illustrated in the enclosed drawings, the device 1 is adapted to align the plate-like workpieces on the side opposite the operator's side of a folder-gluer, namely for a correction also called for on the right. Besides, the folder-gluer has not been represented in the enclosed drawings, since it is not part of the present invention and is not necessary to the understanding of the device 1. Moreover, illustrating the device 1 of the present invention in a configuration for aligning on the side opposite the operator's side rather than on the operator's side is due to the fact that most alignments of plate-like workpieces are carried out on the right. Nevertheless, the right-left inversion of this configuration will be explained afterwards in the description which will follow.
The aligning device 1 comprised of two different parts, one of which is illustrated in
Firstly, the lower aligner member 10 will be described with reference to
As better shown in
In order to improve the support of the plate-like workpieces traveling in the traveling plane 2 in contact with the useful portion 28, a removable supporting bar 30 is arranged which has an upper surface substantially located at the level of the traveling plane 2. This supporting bar is held at the correct height by means of two legs 31 slid into a pair of sleeves 32 which are horizontally slidable between the frames of the folder-gluer, along two crossbars 33 of square section such as illustrated in
To enable correct guiding of the plate-like workpieces parallel to a longitudinal reference line, which line generally corresponds to the longitudinal machine axis, a removable guiding member 40 is arranged at the height of the traveling plane 2 of the plate-like workpieces against the lower guide 13. According to the illustrations in
It will be noted that the lower aligner 10 does not comprise any pivot point able to vary the angle of the lower conveyor 20 with respect to the guiding member 40. However, this is nevertheless possible in the device of the present invention by the opening 12 of the bearing element 11 and its features. Effectively, this opening is used to weaken the material of this bearing element in order to create a relative flexibility between the two parts which it delimits, namely between the lower guide 13 and the upper guide 14, while remaining within the elastic limits of the material. Thus, owing to the slit structure of the bearing element 11, the lower guide 13 remains fixed, once the device positioned between the frames of the folder-gluer, in a vertical rest plane whereas the upper guide 14, by deflection with respect to the lower guide 13, is movable in the horizontal plane.
In order to block the lower conveyor in an angular so-called work position chosen with respect to the guiding member 40, a setting member 50 allows adjusting and blocking the upper guide 14 with respect to the lower guide 13. To this end, a knurled knob 51 extends through an oblong opening 52, which is transversely arranged in an upper square 54, and is screwed in a lower square 53. The lower 53 and upper 54 squares are arranged back to back and fixedly attached respectively to the lower guide 13 and the upper guide 14. In rest position, namely when the upper guide and the lower guide are in the same vertical plane, the knurled knob 51 is preferably located in the middle of the travel of the setting member 50, namely at half passage of the length of the oblong opening 52.
The upper aligner member 60 will now be described with reference to
A removable sheet 80 is arranged against one of the sides of the longitudinal bar 74 and is vertically held by means of two knurled knobs 81. This sheet 80 is folded at its base so as to form a shoe 82 the ends of which are slightly raised. Firstly, this sheet is used as protection, such as a casing, for the uncovered face of the pressure rollers 75, namely the face opposite the one being located on the side of the guiding member 40 when the upper aligner 60 is mounted above the lower aligner as illustrated in
Referring to the operation of the aligning device 1, the machine operator firstly determines the configuration right or left to be adopted to carry out the alignment of the plate-like workpieces. This configuration essentially depends on the type of plate-like workpiece to be worked. According to the size of the plate-like workpieces, he adjusts the lateral position of the lower aligner 10 which moves owing to the rotation, manual or motorized, of an endless screw extending through the nut 18 of the bearing element 11. Being rigidly fixed to the lower guide 13 by means of the bracket 61, the upper aligner 60 is advantageously moved during the same operation. Once the device is correctly positioned, the operator then chooses the face of the longitudinal guiding rail 43 which is most appropriate in accordance with the thickness of the plate-like workpieces to be aligned. Effectively, the sectional face 45 is advantageously adapted to thin workpieces whereas the planar face 46 is rather appropriate for aligning thick plate-like workpieces. The adjustment of the angle of deflection of the lower conveyor 20 can be done in one or the other direction so that the plate-like workpieces can be oriented either towards the operator's side or towards the opposite operator's side in accordance with the chosen configuration. In a configuration for a so-called right alignment, the lower conveyor 20 is inclined towards the operator's side and inversely for a so-called left alignment. To this end, it is sufficient to act on the setting member 50 by unscrewing the knurled knob 51 then to push the upstream end of the lower conveyor 20 towards the chosen side in order to remove it from its vertical rest plane, and finally to tighten the knurled knob 51 in order to block the lower conveyor in the chosen angular position. The upper conveyor can then be adjusted so as to be placed in the same vertical plane as the lower conveyor.
In order to inverse the configuration, for example for changing from a configuration for an alignment on the right to a configuration for an alignment on the left, it is sufficient to carry out the succession of the following operations:
After having carried out these operations, the aligning device 1 should be moved close to the corresponding frame of the machine. Due to the simple design of this device, such a configuration inversion can easily be realized in only 10 to 15 minutes, without having to move heavy loads and without having to withdraw parts of any transverse axis.
As previously described, the lower conveyor 20 is comprised of a belt 21 and the upper conveyor 70 is comprised of a track of pressure rollers 75.
According to a preferred embodiment, the drive pulley 22 is fixedly attached to the lower guide 13 and the useful portion 28 of the belt 21 is supported by a series of rollers of well-known construction (not shown in the drawings).
Since the first aim of the upper conveyor 70 is to exert a certain pressure onto the plate-like workpieces in order to improve their conveying in contact with the lower conveyor 20, an alternative of the object of the present invention could be to remove the upper aligner 60 and to use only the lower aligner 10 if the adherence of the plate-like workpieces on the lower conveyor is sufficient. Such a case could arise, for example, owing to the arrangement of a suction device which acts in conjunction with the lower conveyor 20.
Once installed in a folder-gluer, the aligning device 1 thus advantageously offers the possibility of aligning plate-like workpieces on one as well as the other side of the machine, in a minimum of time and handling. This feature also has a direct economic advantage since it is not necessary to have two aligning devices, one for the operator's side and the other for the side opposite the operator's side, for efficiently cover the totality of possibilities that a folder-gluer could offer.
In addition to its multi-purpose, this device has also the advantage of being light and of economic design owing to better adapted equipment. In this connection, the features of the guiding member 40 are cited as an example, the longitudinal rail of which is of non-massive design obtained by folding without its geometrical properties, namely its perfect straightness having to suffer. With regard to the milling and grinding of massive bars known from prior art, this embodiment is obvious.
Finally, owing to the single structure formed by the lower guide 13 and the upper guide 14, the manufacture and assembly of the device 1 are greatly simplified, the space requirement of the device can be reduced, the arrangement of its members is facilitated and the guiding of the plate-like workpieces is improved.
Numerous improvements can be applied to the device of the present invention within the scope of the claims.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 00686/04 | Apr 2004 | CH | national |
