Table with suction for conveying substrates

Abstract

The invention relates to a table (1) with suction for conveying paper (2) for feeding a processing machine, which comprises a plurality of suction holes (3) through which protrude wheels (4) for conveying the paper (2) and by means of which suction is provided to give traction to the paper (2) as it moves, wherein at least one of the plurality of suction holes (3) comprises an additional support surface (1.1) between the wheel (4) and an inlet end (3.2) and / or between the wheel (4) and an outlet end (3.1) of the suction hole (3), to support the low-rigidity laminar substrate (2) as it moves.

Description

[0001] DESCRIPTION

[0002] SUCTION TABLE FOR TRANSPORTING SUBSTRATES

[0003] Technical sector

[0004] The present invention relates to machines for feeding sheet substrates to a processing machine, and more specifically to a suction feed table used for transporting sheet substrates, preferably from a feed machine to a substrate processing machine. In particular, it relates to a suction table for transporting paper-type sheet substrates.

[0005] State of the art

[0006] For feeding low-rigidity sheet substrates, conventionally, suction cups are used to hold the substrate, or other machines that have suction belts or bands or grippers to pull the substrates and move them to the corresponding processing machine or location.

[0007] On the other hand, for more rigid and heavier laminar substrates such as cardboard, feeding machines are used that consist of supply and guide elements where a stack of laminar substrates is deposited for feeding to a machine that processes said laminar substrates, which will subsequently carry out printing, folding, etc. tasks. In order to feed the laminar substrates individually, said feeding machines comprise a feeding table, which comprises a plurality of wheels that move the laminar substrates. To ensure greater traction and prevent improper movement (for example, slipping between the wheels and the substrate) when feeding each substrate, said feeding tables have a suction system that brings the laminar substrate against the tables, specifically against the wheels.Thus, the table has some rectangular holes, through which the wheels protrude, slightly above the surface of said table, to contact the laminar substrate and through which the suction is produced.

[0008] As mentioned, these types of feeding machines are commonly used for cardboard sheets, however, as an alternative to the existing machines for the transport / feeding of low-rigidity laminar substrates mentioned above, the present invention has provided for their use for paper sheets, or similar in terms of substrate rigidity, however, a series of problems arise.

[0009] The paper, being less rigid, hits the final edge of the holes in the direction of travel due to the suction produced (being more easily sucked, at its external edges and corners, towards the interior of the holes due to its lower rigidity), this produces misalignments that result in poor feeding of the processing machines and consequently in stops that slow down the production process, and even tears in the laminar substrates that make them unusable for later use, etc.

[0010] Another problem is that the paper itself is forced into the holes, causing jams that require a stoppage and are sometimes difficult to resolve without dismantling some part of the suction feed table.

[0011] In view of the solutions currently available, an alternative solution is needed that allows continuous feeding of paper sheets individually and continuously, avoiding jams or defects resulting from the suction of the feeding table, and that can also be versatile for use with more rigid substrates or allow the adaptation of feeding machines for said more rigid substrates.

[0012] Object of the invention

[0013] In order to meet this objective and solve the technical problems discussed so far, as well as providing additional advantages that may arise later, the present invention provides a table with suction for transporting low-rigidity or low-weight, thick laminar substrates, such as paper, plastic, wood (wood veneer), etc., being transported both individually and from a continuous coil of substrate, for feeding to a processing machine, comprising a plurality of holes through which low-rigidity laminar substrate transport wheels protrude, hereinafter referred to as substrate, and through which suction is performed to provide traction to the substrate as it moves, in which at least one of the plurality of holes, and preferably all the holes comprise an additional support surface between the wheel and the input end, and / or between the wheel and the output end of the suction hole, for supporting the substrate during its longitudinal movement along the suction table.

[0014] The outlet end is understood to be the section of the orifice from the middle of the longitudinal orifice to the end of the orifice in the direction of movement of the substrate toward the processing machine. The inlet end corresponds to the end of the suction orifice opposite the outlet end.

[0015] It is understood that the space between the wheel and the ends of the suction hole is taken from the beginning of the suction hole to the closest encounter with the wheel according to the plane defined by the table.

[0016] Thanks to this configuration, after the substrate makes contact with the wheel, if the additional surface is located between the wheel and the output end, or before the substrate makes contact with the wheel, if the additional surface is located between the input end and the wheel, the substrate is prevented from penetrating the hole, avoiding jams or poor substrate feeding. This makes it possible to use the same suction table for rigid substrates such as cardboard, adapting it for use with less rigid substrates such as paper.

[0017] Regarding the advantages over the prior-art gripper feeding system, the present invention provides a solution with greater mechanical simplicity. Gripper systems are normally associated with offset printing machines that require mechanical synchronization; however, the present invention does not require such synchronization of the substrates one by one, since all substrates are detected and printing is activated according to the readings of the control means when appropriate, i.e., electronic synchronization is available.

[0018] Another advantage over this type of gripper system is that the substrates are not subjected to mechanical stress as they do not stretch. This is particularly beneficial when using an inkjet printer, where there is no mechanical contact, ensuring dimensional stability during printing. In offset systems, the pulled substrate makes contact with the printing rollers.

[0019] In general, the suction table of the invention is a simpler construction and allows for more options than traditional systems (belts, strips, or clamps). For example, this design allows for the use of metal wheels instead of rubber wheels under the heating zone.

[0020] According to one option of the invention, the additional support surface defines a geometry of the outlet end and / or the inlet end of the suction orifice with a decreasing section in width, said decreasing section being configured for guiding the substrate.

[0021] Substrate guidance means directing the substrate in the direction of travel and in such a way that, if it tends to enter the hole, said decreasing section forces this portion of substrate to move towards the outside, guiding it towards the outside as the only option in its movement in the direction of advance of the substrate.

[0022] For the interaction of the substrate with the inlet end of the suction hole, the guidance would be interpreted as the tendency of the substrate to advance without entering the suction hole, since, during its advance, the substrate would encounter the narrowest section of the hole, so it will not enter and when it is close to the wheel it will rest on it, helping it to advance and come out upwards in its advance, preventing it from entering the hole.

[0023] Thanks to this configuration, sufficient traction of the substrate is maintained with a respective suction, but due to the resulting decreasing width section after the addition of the support surface, such a substrate guiding action occurs that directs the substrate without it entering the suction holes.

[0024] This support surface defining the tapered section could be arranged on one or both sides of the suction opening, and with symmetrical or different sections on both sides, but its geometry must always be designed to prevent the substrate from colliding with or entering the suction opening. That is, depending on the characteristics of the substrate to be transported, the tapered geometry will be defined to a greater or lesser extent by which the width of the suction opening decreases.

[0025] According to a feature of the invention, the additional support surface is also arranged at the inlet end of the suction orifice, also defining a geometry with a decreasing width, in this case increasing in width in the feed direction. This configuration prevents the substrate from jumping when hitting the inlet edge of the suction orifice; the substrate has more support surface than that corresponding to the prior art and in this way the front ends of the substrate are less likely to be sucked into the holes before the substrate rests on the wheels as it moves forward, so that continuous feeding occurs at high speeds and without problems caused by the interaction between the substrate and the suction orifice.

[0026] According to another feature of the invention, the additional support surface defines an angled outlet and / or inlet geometry, i.e., with straight, inclined edges, and preferably symmetrical with respect to the longitudinal axis of symmetry of the orifice. This improves substrate guidance and promotes continuous feeding without interruptions.

[0027] In another configuration, the outlet and / or inlet ends are defined with an arched geometry. In this case, the edges are smoothed, improving guidance and maintaining a larger suction area.

[0028] Preferably, the additional support surface defines the outlet end and / or the inlet end with a pointed end, so that the straight protruding edge of the suction hole, which could cause problems in the movement of the substrate, is completely eliminated.

[0029] Preferably, the support surface comprises a chamfer on the edge of the hole at the outlet end and / or the inlet end. This chamfer helps guide the substrate to prevent it from hitting the edge, so that upon contact with the inclined surface of the chamfer, the substrate sheet is directed outward if the suction draws it into the hole.

[0030] According to another aspect of the invention, the additional support surface comprises a distribution of through holes that allow the passage of suction. Thanks to this configuration, the substrate can be guided without excessively reducing the suction performance of the table, attempting to compensate for the loss of suction due to the additional support surface. According to a feature of the invention, the support surface can be permanently or removable fixed to the suction hole. It is also contemplated that the suction table itself can be manufactured directly with the aforementioned support surface. Since the additional support surface is removable, it can be used when using substrates with low rigidity, and can be removed when more rigid substrates are used, providing greater versatility to the suction table.The fixing of the support surface could be, for example, by means of a sheet metal with the same dimensions as those corresponding to the conventional suction table but which has a modified hole with an additional support surface, so that when fixing the sheet metal to the suction table the resulting hole is the modified hole with the configuration that prevents the substrate from getting stuck.

[0031] According to another alternative of the invention, the bearing surface is in the form of a mesh that can be fixed to the suction opening. The mesh is fixed to the opening itself, forming said additional bearing surface between the wheel and the ends and / or between the side of the wheel and the side of the suction opening.

[0032] According to another aspect of the invention, the table is contemplated to comprise a distribution of through holes on the table surface around the suction hole. This feature improves the suction, making it similar to that of a conventional suction hole.

[0033] It is contemplated that the features presented above may be combinable according to different embodiments as long as they are compatible.

[0034] The aforementioned features contribute to better feeding of the low-rigidity sheet substrate, preventing jams or misalignments that slow down production.

[0035] Description of the figures

[0036] Figure 1 shows a schematic perspective view of a detail of a prior art suction feed table, in which only one wheel is shown for clarity.

[0037] Figure 2 shows a perspective view of a detail of a suction feeding table object of the invention with the ends of the holes presenting an arched geometry.

[0038] Figure 3 is a top view of a suction feed table like that of Figure 2, showing a sheet of paper.

[0039] Figure 4 is a perspective view of a detail of a suction feed table with a chamfer on the edge of the support surface of the outlet end of the suction hole.

[0040] Figure 5 is a detailed top view of a suction orifice according to the invention, showing the dimensions of a practical example. The dashed line shows the geometry of a prior-art suction orifice.

[0041] Figure 6 is a sectional front view of the table along the median plane of a suction hole according to the embodiment of Figure 5.

[0042] Figure 7 is a top view of an alternative embodiment of the invention, where the dashed line shows the geometry followed by a suction hole of the prior art.

[0043] Figure 8 shows a perspective view of another embodiment in which the additional support surface and the hole distribution in the table are combined.

[0044] Figure 9 is a detailed top view of the embodiment of Figure 8.

[0045] Detailed description of the invention

[0046] As can be seen in figure 1 corresponding to a state-of-the-art suction feeding table, the suction holes (3) have a rectangular geometry and through which the displacement wheel (4) emerges for feeding the sheet of low-rigidity laminar substrate (2) hereinafter, as a practical example, sheet of paper (2), by turning it in the appropriate direction for the forward movement of the substrate.This type of suction holes (3) presents the problem that, for the movement of sheets of paper (2), it produces jamming or misalignment of said paper (2) because, due to the action of the suction and unlike other laminar substrates such as cardboard with greater rigidity, the paper (2) is introduced at the ends into the space between the wheel (4) and the extreme straight edge of the suction hole (3), that is, by having a relatively large suction area, the less rigid paper or substrate is less supported on the table and is exposed to being sucked inwards and collides with the edges or corners when being sucked, etc.

[0047] To overcome these problems, the present invention contemplates a suction table with an additional support surface (1.1) that defines a geometry of the suction hole (3) with the outlet end (3.1) and / or the inlet end (3.2) with a geometry of decreasing width. As can be seen in Figure 2, said decreasing geometry will preferably be arched and ending in a pointed, arrow-like shape, resulting in a modified hole (3').

[0048] This configuration favors the guidance and greater support, on the table (1), of the sheet of paper.

[0049] (2) which as can be seen in figure 3 will move from the left towards a processing machine, or in its simple transport depending on the needs. In this way, the correct suction is maintained to keep the paper (2) traction on the wheels (4) without problems of jams, or movements of the paper (2) caused by the collision with the edges of the suction hole (3), since the modified hole (3') will have its ends (3.T, 3.2') configured for guiding the paper (2).

[0050] According to an alternative embodiment of the invention, as can be seen in Figure 4, so that the guiding is smoother and the paper (2) does not collide against the edges of the modified suction hole (3'), the edge of the support surface (1.1) comprises a chamfer (5) at the outlet end (3.1'), and said chamfer (5) can also be provided at the inlet end (3.2') of the hole (3').

[0051] As a practical non-limiting example of the invention, as can be seen in Figure 5, for a paper substrate (2) of the Kraft or coated paper type, 170g / m 2 , and for a suction hole

[0052] (3) 85mm long, 35mm wide and with a wheel (4) of 110mm diameter; a section reduction has been considered that starts according to the dimension (A) of 23.1 mm, ending in a point and with an arched section that starts from a dimension (B) of 11mm and a radius (R) of 24mm. The chamfer is also made of 2mm x 45°. These measurements will vary depending on the substrate (2), dimensions of the suction hole (3) and the suction force. In this same figure 5, you can see how the additional support surface (1.1) covers part of the suction hole (3) of the state of the art represented in a dashed line. Thus, it is planned that the support surface (1.1) can be a false one, be manufactured in a sheet metal that can be fixed to the table (1) with the configuration of the modified suction hole (3'), or be manufactured entirely on the surface of the suction table (1).

[0053] In Figure 6, the space between the wheel and the end of the hole (3) where the substrate (2) is inserted can be seen, and which, thanks to the geometry of the support surface (1.1), will be guided outwards. The chamfer (5) shown in the same figure contributes to this.

[0054] According to another embodiment, in figure 7, it can be seen how the space between the wheel (4) and the end of the suction hole (3), and between the sides of the wheel (4) and the side of the suction hole (3), has been covered, leaving a modified suction hole (3') with a reduced suction surface. In addition, a distribution of through holes (1.2) has been arranged, which allow the passage of suction, maintaining traction between the paper (2) and the wheel (4). Said holes (1.2) may have different sizes and distribution shapes depending on the needs, and be arranged on the additional support surface (1.1) and / or in the surroundings of the suction hole (3).

[0055] In figures 8 and 9, another alternative embodiment can be seen in which the distribution of holes (1.2) is combined with the support surface (1.1) that defines the angled and pointed output end (3.T). Furthermore, the configuration of the holes (1.2) in this case is in the form of loops, but it could equally be of any shape depending on the needs, always allowing the passage of suction and the support of the paper (2).

Claims

CLAIMS 1.- Suction table (1) for transporting low-rigidity laminar substrates (2) for feeding into a processing machine, comprising a plurality of suction holes (3) through which wheels (4) for transporting the low-rigidity laminar substrate (2) protrude and through which suction is performed to provide traction to the low-rigidity laminar substrate (2) as it moves, where at least one of the plurality of suction holes (3) comprises an additional support surface (1.1) between the wheel (4) and the input end (3.2), and / or between the wheel (4) and the output end (3.1) of the suction hole (3), for supporting the low-rigidity laminar substrate (2) during its movement. 2.- Suction table (1) according to the previous claim, where the support surface (1.1) defines a geometry of the output end (3.1) and / or the input end (3.2) of the suction hole (3) with a decreasing width section configured for guiding the laminar substrate (2) in its movement. 3.- Suction table (1) according to the previous claim, where the support surface (1.1) defines a geometry of the output end (3.1) and / or the angled input end (3.2). 4.- Suction table (1) according to claim 2, where the support surface (1.1) defines a geometry of the output end (3.1) and / or the arched input end (3.2). 5.- Suction table (1) according to any one of the preceding claims, wherein the support surface (1.1) defines a geometry of the output end (3.1) and / or the input end (3.2) ending in a point. 6.- Suction table (1) according to any one of the preceding claims, wherein the support surface (1.1) comprises a chamfer (5) along the edge that defines the hole (3) at the outlet end (3.1) and / or the inlet end (3.2). 7.- Suction table (1) according to any one of the preceding claims, wherein the support surface (1.1) comprises a distribution of through holes (1.2) that allow the passage of suction. 8.- Suction table (1) according to any one of the preceding claims, wherein the support surface (1.1) is permanently or removable attachable to the suction hole (3). 9.- Suction table (1) according to claim 1, where the support surface (1.1) is a mesh that can be fixed to the suction hole (3). 10.- Suction table (1) according to any one of the preceding claims, comprising a distribution of through holes (1.2) on the surface of the table (1) around the suction hole (3).

Images