The present invention concerns a machine for processing board elements, comprising a feed board provided with means for conveying the board elements.
A processing machine, for example a flat-bed cutter type forwarding machine, is notably used in the printing and packaging industry, for example for making up cardboard boxes from board elements, such as sheets.
In the machine, the board elements are taken up by a conveyor, taking the form of clamping bars mounted at regular intervals on a row of endless chains that enables the board elements to be brought to the various successive processing stations of the machine. The row of chains moves and stops periodically with a timed progress so that during each movement all the clamping bars that have taken up board elements are moved from an upstream station to the next adjacent downstream station.
In the cutting machine example, the stations are successively a station for cutting board elements with a cutting form, a station for ejecting waste with an ejection form, and a station for receiving a stack of the cut board elements.
In an insertion station at an entry of the machine the board elements are taken from the top of a stack placed on the upstream side of the machine. The board elements are disposed in the form of a layer and conveyed in the upstream to downstream direction by a feed board. To form the layer, the board element on the top of the stack is taken up from behind and then pushed forward by an inserter, the front part of the board element that has been taken up sliding under the preceding board element already taken up and then released.
The board elements of the layer are then each precisely positioned laterally and longitudinally before being taken up by the clamping bars. Positioning is effected at one of the downstream ends of the feed board. Positioning is carried out either with the board elements stopped by front and lateral abutments against which the edges of the board element bear or using a more sophisticated system that does not necessitate stopping of the board elements.
The feed board is provided with conveyor means for conveying the board elements in the upstream to downstream direction. The feed board has an inclined top plane, which may be a metal plate or a wooden board, for example, mounted on a frame. One or more passages of rectangular shape are provided in the top plane.
A plane upper face of an endless conveyor belt is engaged in the passage and is substantially flush with the top plane. When a plurality of belts is present, they are disposed side-by-side over the width of the top plane and spaced by portions of the plane having a rectangular shape.
A processing machine can achieve processing rates from 8000 to 12000 board elements per hour. Because of the abrasive properties of the material constituting the board elements, this rapid movement of the board elements over the feed board generates high wear of the belt(s).
A worn belt loses its flexibility properties, stretches, or even breaks. The consequence of using a worn belt is that the board elements will no longer be placed precisely and regularly in the layer. This causes modifications of the positioning of the board elements conveyed by the belts at the exit from the feed board. These positioning modifications lead to incorrect positioning where the clamping bars take up the board elements, incorrect processing of the board elements, or even the board elements jamming in the machine. Rollers or wheels retaining the belt(s) may also become worn or even break.
The conveyor belt and its rollers therefore constitute wear parts that must be changed regularly. A first technique consists in dismantling the feed board and the components of the top plane, removing the defective belt, fitting the new belt and then reassembling everything, carrying out any necessary adjustments. A second and faster technique consists in cutting the worn belt while in the machine. The new belt is fitted by directly butt-jointing its respective free ends by bonding or by welding while in the machine. The new belt must be tensioned.
All these maintenance operations take time. These operations are sources of error, for example where the flatness at the level of the joint in the butt-jointed new belt is concerned. These operations prove somewhat impractical, increase the machine downtime, and are therefore more tiring for the operator. During these downtimes the machine is no longer in production.
A main objective of the present invention consists in producing a machine for processing board elements equipped with a feed board. A second objective is to simplify, facilitate and accelerate changing the conveyor means. A third objective is to make feed board maintenance operations more ergonomic. A further objective is to solve the technical problems referred to in connection with the prior art.
A machine in accordance with the invention for processing board elements is equipped with:
According to a main aspect of the present invention, the machine for processing board elements is characterized in that the conveyor means for the board elements take the form of at least one removable conveyor cassette with endless conveyor belt(s) inserted in, fixed to and adapted to be removed from the frame of the feed board.
By way of non-exhaustive example, the board element is defined as being in a board or sheet material, such as paper, flat cardboard, corrugated cardboard, laminated corrugated cardboard, flexible plastic (for example polyethylene (PE), polyethylene terephthalate (PET), bi-oriented polypropylene (BOPP) or other polymers) or other materials.
The board element is processed in the processing machine. The processing may be cutting, the processing machine being, by way of non-exhaustive example, a flat-bed cutting machine. The processing may be applied to the surface of the element, to apply graphic signs to it and/or to impart an aesthetic appearance to it. The processing may be scoring, embossing, forming, hot foil stamping, affixing labels or holograms, etc. The processed element could include a layer of varnish covering all or part of the surface.
The upstream and downstream directions are defined with reference to the direction of longitudinal movement of the element through the processing machine from the insertion station.
In other words, the operator will replace a cassette with worn belt(s) with a new cassette with new belt(s). Maintenance is easier with a cassette that is easily dismantled in an appropriate shop away from the machine where a new endless belt, already in loop form and of better quality than a butt-jointed belt, can be placed in the cassette immediately as a replacement for the worn belt. The operator will also be able to use a replacement conveyor cassette that is ready for use already and very quickly substitute the replacement cassette for the cassette with worn belt(s) with limited machine downtime.
According to another aspect of the invention a removable conveyor cassette for a feed board positioned on the upstream side of a station for processing board elements in a machine for processing board elements includes a structure, at least two upstream and downstream rollers carried by the structure, at least one endless conveyor belt tensioned by the two upstream and downstream rollers, defining a plane upper face, conveying at least one element over the plane upper face, and driven by a driving shaft of the board, the conveyor cassette being adapted to be inserted in, fixed to and removed from a frame at the level of the feed board.
According to a further aspect of the invention a machine for processing board elements of the flat-bed cutter forwarding machine type is characterized in that it includes at least one removable cassette inserted in a feed board and having one or more of the technical features described below and claimed.
The invention will be more clearly understood and its various advantages and features will emerge more clearly from the following description of a nonlimiting embodiment given with reference to the appended diagrammatic drawings, in which:
The press is equipped in this order and in the upstream to downstream direction with an insertion station 2, a feed board 3, a processing station 4, a waste ejection station 6 and a reception station 7. The processing station 4 incorporates a flat-bed cutter, the board passing between a mobile lower support on which a cutting form is mounted and a fixed upper support.
Each board to be cut is taken up and conveyed in the longitudinal direction (arrow T in
The feed board 3 has an upper area 9 with an upstream side 11 and a downstream side 12. The sheets are placed in a layer on the upstream side 11. The layer of sheets moves over the upper area 9 of the board 3. The sheets are each positioned precisely on the downstream side 12 of the board 3 by tamping abutments or by a mobile mechanism (not shown).
The feed board 3 includes a lower frame 13. The feed board 3 is provided with conveyor means with two endless drive belts 14 and 16 for conveying the layer (see
The two drive belts 14 and 16 are deployed and move longitudinally (arrow M in
According to the invention, the conveyor means take the form of at least one removable conveyor cassette and in the present case two conveyor cassettes 23 and 24. The first belt 14 at the front is part of the first cassette 23 at the front and the second belt 16 at the rear is part of the second cassette 24 at the rear. Each of the two cassettes 23 and 24 is an independent unit provided in this case with a single endless conveyor belt 14 and 16.
The cassette 23 or 24 is adapted to be inserted into the frame 13 in the downward direction (arrow I in
Each cassette 23 or 24 includes a retaining structure 26. An upstream end of the structure 26 carries the axle of an upstream upper roller 27. A downstream end of the structure 26 carries the axle of a downstream upper roller 28. The endless belt 14 is tensioned between these two upstream and downstream rollers 27 and 28. The two rollers 27 and 28 and their respective upstream and downstream upper positions define the plane upper face of the belt 14 when the cassette 23 accompanied by its structure 26 is placed in the frame 13. The structure 26 is constructed with two perforated lateral plates joined together by spacers.
The belt 14 is an endless loop passing over and deflected by the two upstream and downstream rollers 27 and 28. The belt 14 is advanced longitudinally (arrow M), being pressed onto part of the circumference of a driving shaft 29 of the board 3 and cooperating with it by friction. The driving shaft 29 is situated under the upper area 9 of the board 3. The driving shaft 29 turns (arrow D in
To maintain the path of the belt 14, three additional idler rollers 31, 32 and 33 are provided, mounted on the structure 26 (only their respective axles can be seen clearly in
After its plane upper face, the return path of the belt 14 (arrow B in
It is beneficial if the cassette 23 includes means for tensioning and relaxing the belt 14 (see
In an upstream longitudinal position of the downstream lower roller 33 the belt 14 is relaxed. In a downstream lower downstream longitudinal position 33 the belt is tensioned. The downstream lower roller 33 preferably includes an axle 34. Each of the two ends of the axle 34 slides in the upstream or downstream direction in a longitudinal slot 36 provided in each of the two plates of the structure 26 of the cassette 23.
The means for tensioning and relaxing the belt 14 advantageously include a holding device 37 mechanically connected to the axle 34 of the downstream lower idler roller 33 and adapted to pivot relative to it (arrow P in
The holding device 37 is fastened to return means 41 that bear on a fixed point 42 provided for example at the level of each of the two plates of the structure 26. The return means 38 are of cylinder type, the body of the cylinder being fixed to a spacer 43 between the two flanges 39 and the piston rod of the cylinder being fixed to the rod 38. The spacer 43 is housed in two notches forming the fixed points 42 of each of the two plates of the structure 26.
The means for tensioning and relaxing the belt 14, with the downstream lower idler roller 33, the holding device 37 and the return means 38, are preferably demountable, for example by unscrewing one flange of the holding device 37.
A method of changing the conveyor belt 14 in the feed board 3 positioned on the upstream side of the board processing station 4 for the flat-bed-type cutting machine 1 comprises the steps consisting in demounting and extracting the cassette 23 (step O); removing the belt 14; fitting a new belt 14; and inserting and fixing the cassette 23. This method comprises a supplementary step consisting in relaxing the belt 14 and then tensioning the new belt 14. This method comprises a supplementary step consisting in demounting the means for tensioning and relaxing the belt 14.
The present invention is not limited to the embodiments described and shown. Numerous modifications may be made without departing from the framework defined by the scope of the set of claims.
Number | Date | Country | Kind |
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12003239.6 | May 2012 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/001226 | 4/24/2013 | WO | 00 |