EP4289579A1 - Device for processing a workpiece - Google Patents

Abstract

The invention relates to a device (1) for processing a workpiece (2), which preferably consists at least in sections of wood, wood material or plastic, comprising a processing unit (10) for processing the workpiece (2), a conveying unit (20) for conveying the Workpiece (2) in relation to the processing unit (10), wherein the conveying unit (20) has at least one endlessly rotating belt (30) which has an outer peripheral surface (32) which is set up to be attached to the respective workpiece (2) during conveying ) to rest, and a guide unit (22) for guiding the belt (30) along a circulation path. The belt (30) is elastically deformable in a direction transverse to its outer peripheral surface (32).

Description

Technical area

The invention relates to a device (1) for processing a workpiece (2), which preferably consists at least in sections of wood, wood material or plastic, according to the preamble of claim 1.

State of the art

In the furniture and component industry, workpieces are often processed in processing devices through which they are conveyed along processing units. To convey the workpieces, such processing devices often have a conveyor track and a so-called upper pressure. The conveyor track and upper pressure can have different conveying means, such as conveyor chains, conveyor belts, roller conveyors, etc.

This is how it reveals EP 2 614 940 A1 a generic processing device in which several conveyor tracks and top prints are provided. Such devices have proven themselves in practice. However, it has been shown that adaptability of the devices to variable workpiece thicknesses entails a high level of design effort.

Presentation of the invention

The invention is based on the object of providing a device for processing a workpiece of the type mentioned at the outset, which, with a simple construction, has good adaptability to variable workpiece thicknesses.

This object is achieved according to the invention by a device for machining a workpiece according to claim 1. Particularly preferred developments of the invention are specified in the dependent claims.

The invention is based on the idea of equipping the at least one belt of the conveyor unit with a functionality for adapting to variable workpiece thicknesses. For this purpose, the invention provides that the belt is elastically deformable in a direction transverse to its outer peripheral surface.

In this way, the construction of the processing device or the conveyor unit can be significantly simplified. Until now, the belts were usually mounted on rollers, which in turn sat on deflectable roller levers so that different workpiece thicknesses could be conveyed. Such complex substructures are unnecessary thanks to the belt according to the invention, since the belt can compensate for changing workpiece thicknesses thanks to its elasticity. In addition, there is also a more uniform contact pressure. This not only avoids pressure peaks, but also allows shorter workpieces to be conveyed (in the conveying direction).

According to a further development of the invention it is provided that the elastic rigidity of the belt in a direction transverse to its outer peripheral surface at least in sections increases at least once with increasing deformation. In this way, a hybrid belt is provided, so to speak, which has a relatively low rigidity in a first deformation range and a greater rigidity in at least one further deformation range (with increasing deformation). The belt can therefore fulfill a dual function, namely enabling particularly good adaptability in its first deformation range and providing sufficient stability for clamping workpieces in its further deformation range. It is particularly preferred that the stiffness in the further deformation region is at least five times greater than the stiffness in the first deformation region, although the invention is not limited to this.

The belt can be designed in different ways within the scope of the invention. According to a further development of the invention, however, it is provided that the belt has at least two layers which have elastic stiffnesses that differ from one another in a direction transverse to its outer peripheral surface. The layer structure allows different mechanical properties to be combined particularly well. For example, the outer layers can have a sufficiently high resistance to the loads that occur, while at least one inner layer can have a lower rigidity in order to achieve the desired elastic deformability. A variety of other layer structures are also possible within the scope of the invention.

It is particularly preferred that at least two layers of the belt have different materials. In this way, the different elastic stiffnesses of the layers can be achieved with ease of production, and additional functionalities can also be achieved through suitable material selection.

Alternatively or additionally, according to a further development of the invention, it is provided that the belt has one or more cavities. By providing one or more cavities, the rigidity of the belt can be controlled in a targeted manner, so that the desired elastic deformability can be achieved in a particularly simple manner and, if necessary, using only a single material.

It is particularly preferred that adjacent cavities are each separated by a web, which preferably has a smaller thickness in the direction of extension of the belt than the cavities. The webs allow a sufficient basic rigidity of the belt to be maintained, and by appropriately arranging the webs, additional functions can also be fulfilled, such as stabilizing the belt in the area of the contact surfaces with gears. At the same time, the preferably relatively narrow (compared to the cavities) dimensioning of the webs enables a sufficient reduction in belt stiffness to be achieved in the respective area.

According to a further development of the invention, it is provided that the guide unit has, at least in some areas, a sliding guide on which an inner peripheral surface of the belt slides. This results in a particularly simple construction of the device according to the invention, since, for example, no support rollers, deflection levers or the like are required, but the belt simply slides on a suitable sliding guide.

It is particularly preferred that the sliding guide has a sliding surface that is coated and/or hard-anodized with a sliding coating, such as PTFE in particular. In this way, not only does the sliding guide have a high level of durability, but the operation of the belt is also improved particularly quiet and requires low driving force. Furthermore, the durability of the belt is also increased.

In this regard, it is also preferred that the inner circumferential surface of the belt is at least partially coated with a sliding coating such as, in particular, PTFE and/or polyamide.

According to a further development of the invention, the guide unit can have a roller guide at least in some areas, which is particularly advantageous at very high conveying speeds or pressure forces. The design of the conveyor belt according to the invention enables the rollers to be advantageously mounted firmly, which simplifies the construction.

With regard to the conveying concept, the belt can be designed in different ways, in principle also as a V-belt. According to a further development of the invention, however, it is particularly preferred that the belt is designed as a toothed belt. This makes it possible to realize a significantly more precise conveying operation, in which the feed of the belt (if it is driven) can be precisely coordinated with other feed elements of the device. It should be noted that the use of a V-belt was not considered in previous devices due to the usually complicated support structures, but is now advantageously made possible by the concept according to the invention.

According to a further development of the invention, it is provided that the conveyor unit further has a support unit which is set up to support the workpiece during conveyance and preferably has an endless circulating element, such as in particular a chain. The combination of the support element with the at least one belt results in secure guidance and stabilization of the workpiece, As a result, precise and quick machining of the workpiece is possible with a simple design. The use of a conveyor chain enables the conveying process to be highly dynamic with high durability and precision.

The at least one belt described above can in principle be a passive belt that is not actively driven, but rather merely rolls on a conveyed workpiece in order to support or clamp it. According to a further development of the invention, however, it is provided that the conveyor unit has at least one drive for driving the belt, so that this can also contribute to the advance of the workpiece. Alternatively or additionally, the device can also have at least one drive for driving the support unit, the drive for driving the belt and the drive for driving the support unit preferably being synchronized with one another. The combination of both drives results in a precise and at the same time highly dynamic conveying process that combines excellent processing quality with a high workpiece throughput.

Brief description of the drawings

• Fig. 1 shows schematically a side view of a device for machining a workpiece according to an embodiment of the invention;
• Fig. 2 shows schematically a section of a side view of a belt;
• Fig. 3 shows schematically various partial views of a belt;
• Fig. 4 shows schematically various partial views of a belt.

Detailed description of embodiments

Embodiments of the invention are described in detail below with reference to the accompanying figures.

A device 1 for machining a workpiece 2 is in Fig. 1 shown schematically in a side view. The device 1 is used to process workpieces 2, which consist, for example, of wood, wood materials, plastic or similar composite materials, as are widely used in the furniture and component industry. The workpieces 2 can be plate-shaped or strip-shaped, for example.

To process the workpieces 2, the device 1 first includes a processing unit 10. This can carry out a wide variety of processing operations, such as machining such as drilling, milling, sawing, etc., but also finishing operations, such as applying coating material, painting, printing, etc For this purpose, the processing unit 10 can also combine several processing means.

In addition, a conveyor unit 20 is provided, which conveys the respective workpiece 2 along or through the processing unit 10. In the present embodiment, the conveyor unit 20 initially comprises a support unit, which in the present embodiment comprises a conveyor chain 42. In the present embodiment, chain plates 44 are attached to the conveyor chain 42, on which the respective workpieces 2 are supported. The conveyor chain 42 is driven in rotation by means of a drive and moves in the process Fig. 1 from left to right (or vice versa). The conveyor chain 42 can move for example, by suitable rollers on a guide (not shown) or support unit 40.

In addition, the conveyor unit 20 in the present embodiment includes a so-called upper pressure, which is formed by one or more circulating belts 30, which is guided along a circulating path by a bar-shaped guide unit 22. A conveying gap for the respective workpieces 2 is defined between the belt 32 and the conveyor chain 42 or the chain plates 44, so that the belt 30 rests with its outer peripheral surface 32 on the respective workpiece 2, while the workpiece 2 is supported on at least one chain plate 44 .

The belt slides in the area of its inner peripheral surface 33 on a sliding surface 26 of a sliding guide 24 which is arranged on the guide unit 22. In the present embodiment, the sliding surface 26 is hard-anodized and coated with PTFE (Teflon). Likewise, the inner peripheral surface 323 of the belt 30 is coated with PTFE and/or polyamide (PAR/PAZ) in the present embodiment. Although not shown in the figures, the guide unit (22) can at least partially - alternatively or additionally - have a roller guide, the rollers of which are preferably fixedly mounted.

Furthermore, the belt is deflected via deflection rollers 27 at the ends of the guide unit 22, with at least one deflection roller (right in Fig. 1 ) a drive 28 for driving the deflection roller 27 and thus the belt 30 is located.

The drive 28 is advantageously synchronized with the drive 29, so that the conveyor chain 42 and the belt 32 are driven synchronously with one another and can convey a workpiece 2 with corresponding precision. In order to enable particularly synchronous operation, the belt 33 is a toothed belt carried out what is in the Figures 2 to 4 is best recognized. In this case, the deflection wheels 27 have a complementary tooth profile for secure and precise engagement between the belt 30 and the deflection wheels 27.

According to the invention, the belt itself is elastically deformable in a direction transverse to its outer peripheral surface 32. This elastic deformability can be achieved, for example, through suitable material selection, through a suitable layer structure or through various structural measures on or in the belt, which is exemplified with reference to Figures 2 to 4 is described.

The in Fig. 2 Belt 30 shown in a schematic and partial side view has several layers 34, 35 and 36. The middle layer 34 has a lower elastic stiffness in a direction transverse to its outer peripheral surface 32 than the outer layer 36 and / or the inner layer 35 This enables a deformation behavior in which the belt 30 initially has a relatively low rigidity when a load occurs transversely to its outer peripheral surface 32, which results primarily from the comparatively low elastic rigidity of the middle layer 34. As soon as the middle layer 34 is largely or completely compressed, the overall stiffness of the belt 30 increases sharply transverse to the direction of extension of the outer peripheral surface 32 and can then be, for example, five times or more of the previous stiffness.

Alternatively or additionally, the strap can be in Fig. 3 have the illustrated structure. In this embodiment, the belt has a meandering cavity 38 predominantly in its interior, although the cavity 38 can also have a variety of other geometries. Furthermore, a foam that defines cavities can also be used.

By providing the cavity, the belt again has a comparatively low rigidity when loaded transversely to its outer peripheral surface 32. As soon as the cavity has largely or completely closed as a result of the load, the rigidity of the belt 30 increases sharply, so that it is, so to speak, a hybrid belt, analogous to the embodiment described above.

Another embodiment of the belt is in Fig. 4 illustrated. In this embodiment, the belt 30 has a plurality of cavities 38 transverse to its endless direction of rotation, which are separated from one another by webs 39. It should be noted that the number, geometry and direction of extension of the cavities can be varied in many ways within the scope of the invention. In any case, the cavities result in a targeted reduction in the rigidity of the belt 30 transversely to its outer peripheral surface 32, with the rigidity of the belt again increasing sharply as soon as the cavities have largely or completely closed as a result of an external load.

The configurations of the belt 30 described above as examples enable the belt to deform elastically when a workpiece is fed into the conveying gap between the conveyor chain 42 and the belt 30. This allows the belt to adapt flexibly to changing workpiece thicknesses, so that the construction of the device according to the invention can be considerably simplified.

Claims (13)

Device (1) for processing a workpiece (2), which preferably consists at least in sections of wood, wood material or plastic, comprising: a processing unit (10) for processing the workpiece (2), a conveyor unit (20) for conveying the workpiece (2) with respect to the processing unit (10), the conveyor unit (20) having: at least one endlessly rotating belt (30) which has an outer peripheral surface (32) which is designed to rest against the respective workpiece (2) during conveying, and a guide unit (22) for guiding the belt (30) along a circulation path, characterized in that the belt (30) is elastically deformable in a direction transverse to its outer peripheral surface (32). Device according to claim 1, in which the elastic rigidity of the belt (30) increases at least once in a direction transverse to its outer peripheral surface (32) at least in sections as the deformation increases. Apparatus according to claim 1 or 2, wherein the belt (30) has at least two layers (34, 36) having different elastic stiffnesses from one another in a direction transverse to its outer peripheral surface (32). The device of claim 3, wherein at least two layers (34, 36) of the belt (30) comprise different materials. Device according to one of the preceding claims, in which the belt (30) has one or more cavities (38). Device according to claim 5, in which adjacent cavities (38) are each separated by a web (39), which preferably has a smaller thickness than the cavities in the direction of extension of the belt (30). Device according to one of the preceding claims, in which the guide unit (22) has, at least in some areas, a sliding guide (24) on which an inner peripheral surface (33) of the belt (30) slides. Device according to claim 7, in which the sliding guide (24) has a sliding surface (26) which is coated and/or hard-anodized with a sliding coating such as in particular PTFE. Device according to one of the preceding claims, in which an inner circumferential surface (33) of the belt (30) is at least partially coated with a sliding coating, such as in particular PTFE and/or polyamide. Device according to one of the preceding claims, in which the guide unit (22) has a roller guide at least in some areas, the rollers preferably being fixedly mounted. Device according to one of the preceding claims, in which the belt (30) is designed as a toothed belt. Device according to one of the preceding claims, in which the conveying unit (20) further has a support unit (40) which is set up to support the workpiece (2) during conveying and preferably has an endless circulating element (42), in particular a chain. Device according to one of the preceding claims, in which the conveyor unit (20) has at least one drive (28) for driving the belt (30) and/or at least one drive (29) for driving the support unit, preferably the drives (28, 29 ) are synchronized.

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