Device for supplying sheet-like materials

The invention relates to a sheet material feeding device, such as sheets of cardboard, paper, tin, aluminum, etc ...

The invention applies to a device of this type designed to dispense such sheets one by one to a processing station or processing. In such a system, the sheets are stacked on a tray slatted, usually made of wood, commonly called palette.

The invention particularly relates to a means for automatically executing automatically or almost all of the operations of discharging an empty tray and set up another plate supporting a new stack of paper without interruption in the delivery said sheets or significant disturbance of the sheets distribution process.

In a device of the type defined above, the plate supporting the sheet stack is placed on a lift mechanism which raises the whole gradually as and when the sheets are distributed to compensate the decrease in height of the stack. When only a limited number of sheets, the tray must be evacuated and put in place a new battery supported by another plate. If we want to avoid disturbing the distribution process, grab bars, commonly called swords crept manually between the non-contiguous boards of the plate to support the few remaining sheets. These bars are fastened to fixed support or an auxiliary elevator to continue the distribution process. After the establishment of these bars, the tray is lowered and evacuated. A new battery is then placed on the lifting mechanism is raised until the top of the stack arrives at the level of the bars or swords, which are then removed. This manual process involves the mobilization of at least one operator for a considerable time and requires from him a certain Dexter ity for maneuver support bars can be damaging to the products, including sheets likely to be scratched.

We tried to automate this process. For example, British Patent No. 2,059,390 describes a machine comprising a lifting mechanism capable of receiving a tray of leaves and a temporary support mechanism for supporting a number of sheets during a gear shift. The temporary support mechanism comprises bars connected with cylinders and the bars may be engaged in the interstices of a plateau. DE 1,095,297 describes a similar system.

The automation of this process attempts have so far met with a difficulty related to size differences and variations in positioning trays or pallets. Indeed, if the tray is shifted or skewed relative to the stack, the interstices. which said support rods can be engaged are variable and unpredictable locations.

The invention solves this problem and proposes a feeding device to automatic or virtually automatic, permitting in particular the change splateaux more easily and without risk of damaging the sheets of material.

In this spirit, the invention thus relates essentially a sheet material feeding device, said sheets are stacked on a tray openwork of the type comprising a lifting mechanism that can support such a tray of leaves and a mechanism temporary support to support a number of sheets for a tray switching, and wherein said temporary support mechanism comprises a plurality of bars having respective free ends and also linked to or forming part of the respective cylinders may be moved, according to their own longitudinal directions beneath said sheets into interstices of an aforementioned plate, characterized in that said jacks are carried by respective moving elements designed to place the free ends of said rods opposite to such respective interstices.

According to another advantageous feature of the invention, each support bar, in association with its actuating cylinder, is a probe moved by the moving along the shelf for an automatic search of the aforementioned gap.

The invention will be better understood and other advantages thereof will appear more clearly in light of the following description of a possible embodiment of a device in accordance with its principle, given solely by way of example and with reference to the accompanying drawings in which:<ul><li>FIG 1 is a general plan view of a sheet feeding device according to the invention;</li><li>Figure 2 is a detail view showing a support bar and actuating cylinder; and</li><li>Figure 3 is a block diagram illustrating the control of one of the moving elements of the device.</li></ul>

Referring to the drawings, the sheet feeding device 11 includes an elevator mechanism which has been shown that a base 12 secured to move vertically (under the action of any suitable mechanical means), a fixed stop 13 and a movable stop 14, both perpendicular to the dispensing direction (indicated by arrow F) of the sheets 15 and two lateral flanges 17, 18 parallel to said dispensing direction and whose position is adjustable in function of the sheet 15 format . distribution means, not shown, are arranged at the top of the device for collecting the leaves one by one and evacuate in the direction of the arrow F. the base 12 receives a stack of sheets 15; This battery is typically placed on a grate plate 21, of wood, commonly called palette. Such plateaus, often rudimentary construction, with non-contiguous boards, naturally contain interstices 22 which are utilized for the establishment of the usual support bars which have been discussed above. However, the dimensions of the trays are neither precise nor standardized, so that the positions of said interstices within the square or rectangular frame defined by the stops 13, 14 and the flanges 17, 18, vary from cell the other. On the other hand, the tray has sometimes through (as shown) relative to the sheet stack itself, which accentuates the problem with respect to location of the interstices 22.

The feeding device 11 is further provided with a temporary support mechanism 25 for supporting a number of sheets during tray changing. According to the invention, this mechanism includes a plurality of bars 26 (four in the example shown) connected to or forming part of jacks 27, tires. The assembly is such that each bar can move in its own longitudinal direction, with the remaining leaves, engaging in gaps 22 above. In addition, the cylinders 27 are carried by respective moving elements 29, designed to place the bar beside such gaps 22. In the example shown, each cylinder 27 is arranged parallel to the corresponding bar 26, perpendicular to the direction of F distribution, to reduce the size of the device, on the sides. One end of the bar is coupled to the rod 27<u>at</u> of the jack. The free end 30 of the bar 26 is stylus office may come into contact with one side of a plate 21 during movement of the moving 29 party. To this end, this end 30 can be rounded, as shown, or provided with a roller. In addition, each bar 26 is provided with a plurality of rollers 31 arranged to make contact with the leaves and avoid scratches. As shown in Figure 2, the rollers 31 are mounted along the bar 26 by alternately projecting upwardly and downwardly. Each movable element, on which is mounted a cylinder 27, is essentially constituted by a pneumatic cylinder 35 secured via a support 36 to one of the two flanges 17, 18. The elongation of the actuator 35 thus determines the position of the assembly constituted by the bar 26 and the cylinder 27 along a side of the stack. The end 30, forming probe, of each rod 26 can thus move along a certain stroke by remaining in contact with the edge of a plate 21 (when the latter has reached the level of the bars 26) and operating fluid supply means is arranged to apply to the actuator 27 a low pressure during the movement of the moving element, that is to say, during part of the stroke of the cylinder 35 and a corresponding high pressure the end of a probe phase. These actuating fluid supply means are illustrated in Figure 3. The end of a probe phase is determined by detecting means 38 responsive to the stroke of the actuator 27. In the example specifically described, the cylinder 27 is powered by either of two sources of compressed air, a source of low pressure LP and a source of high pressure HP, via a three-way solenoid 40 controlled by a control unit 41 of the electromechanical type or another whose design is within reach of the skilled person. The detection means 38 comprise, for example, a cam 42 whose position is representative of the longitudinal displacement of the bar 26, and a sensor 45, for example a simple electromechanical contactor, positioned to be actuated by the cam and electrically connected to drive the control unit 41. the output of the latter is also connected to the control input of a solenoid valve 46 controlling the isolation of the actuator 35 from its control pressure and in simultaneous open. It is therefore conceivable that the detection means 38 are combined with fluidic switching means (40, 41) connected to supply the cylinder 27 to a low pressure or high pressure. The pressure switch is when the bar 26 is committed, during the scanning of a predetermined distance in a gap tea. In addition, it appears that, thanks to the connection between the control unit 41 and the solenoid 46, the moving element is controlled by or operates in synchronism with the fluid switching means, so as to stop the actuator 35 from displacement of the assembly constituted by the cylinder 27 and the bar 26 substantially simultaneously with the admission of high pressure in the cylinder 27.

At the beginning of each plate change cycle, the cylinders 35 define starting positions for the bars 26, these positions being the nearest fixed and mobile stops 13, 14. The starting position is fixed for mobile crews located the side of the fixed stop 13 and a "floating" depending on the size of the sheets, for the moving elements located on the side of the movable stop 14. for this purpose each cylinder 35 on the side of the movable stop comprises two opposed rods, the a supporting cylinder 27 and the other forming a reference probe 48 comes into contact with the movable stop 14. the assembly is completed by four retractable pins 49 extend from the vicinity of the edges of the sheets. There are two opposing fingers arranged along the direction of the axis of distribution and two others in a perpendicular direction, between the bars 26.

The operation is as follows.

When the base 12 has reached a certain height and the tray (most with only a small amount of leaves) is height of the bars 26, the low pressure is admitted to the cylinders 27 along with 35 cylinders are supplied to start generating probing the edges of the plateau by the different ends 30 of the bars 26. Each bar and ends up meeting a gap 22 and commit to it. When a bar is sufficiently engaged in the gap, the corresponding cam 42 actuates the switch 45, which controls both the pressure increase in the cylinder 27 and the cylinder stop 35 which is then made free. The bar 26 can then engage a maximum in the gap. All four bars are engaged, the leaves that remain on the board, are supported and the base 12 can be lowered with said empty tray. The latter is then removed and replaced with a new battery, supported by another plate. The base is raised until the top of the stack is again at the support bars 26. The bars are then withdrawn by actuation of the cylinders 27 so that the last sheets of the previous stack come to rest on the new battery. The distribution process is thus practically not disturbed.