Patent Application
20220241815
The invention relates to a device and a method for coating workpieces preferably consisting at least in parts of wood, wood materials, plastic, aluminium or the like. The invention furthermore relates to the use of a device according to the invention.
In the furniture and components industry, for example, workpieces are often provided with a coating material on one their surfaces, for instance an edge. The coating material is usually attached by means of a suitable adhesive applied to the workpiece or coating material in the form of a hot-melt adhesive, for example. However, an adhesive can also be used that is applied to the workpiece or coating material and is activated during the coating process by means of hot air.
Disclosed in DE 202012013116 U1 is a nozzle arrangement for an edge-strip application device that is suitable for applying hot air to an edge strip or workpiece. This nozzle arrangement comprises at least two groups of air outlet openings and a number of cylindrical closure members corresponding to the number of groups of air outlet openings.
However, it has been shown that the sealing of closure members and in particular the sealing of closure members to which hot air is applied is complex and expensive.
Furthermore, closure members tend to get stuck or jam during traversing or displacement movements. In addition, the closure members disclosed in DE 202012013116 U1 are associated with increased manufacturing costs owing to their geometry and interaction. The comparatively large contact areas between the closure members and other components of the nozzle arrangement also promote wear of the device.
An object of the invention is to provide a simple and efficient way of activating an adhesive on a coating material and/or on a workpiece.
According to the invention, this object is solved by a device according to claim 1. Preferred embodiments are specified in the sub-claims.
A device according to the invention for coating workpieces preferably consisting at least in parts of wood, wood materials, plastic, aluminium or the like, comprises: a feed device for feeding a coating material; a pressing device for pressing the coating material onto a surface of a workpiece; a conveying device for inducing a relative movement between the pressing device and the respective workpiece; and an activation device for activating an adhesive on a coating material fed by the feed device and/or for activating an adhesive on a surface of a workpiece to be coated. The activation device comprises at least one supply line for supplying an activation medium as well as a nozzle body having an activation medium inlet duct and an activation medium outlet region. The activation medium outlet region comprises at least one outlet opening, preferably at least two groups of outlet openings. The activation device further comprises precisely one closure means that is configured to close the outlet opening and/or individual outlet openings of the activation medium outlet region at least in parts.
The activation medium may be, for example, heated air or another gas.
In the present context, a group of outlet openings may comprise 2, 10 or 100 outlet openings, for example. A group of outlet openings may be formed, for instance, by outlet openings arranged next to each other or one below the other. However, a group of outlet openings may also be formed in such a manner that individual outlet openings of a substantially uniform grid of outlet openings are assigned to one group. An activation medium outlet region may comprise a grid of outlet openings, for example, a grid in which outlet openings are arranged in a horizontal direction and a vertical direction. The closure means may be configured to simultaneously close outlet openings of different groups of outlet openings.
In the present case, an outlet opening is deemed to be closed when an activation medium introduced into the nozzle body through the activation medium inlet duct is substantially prevented from exiting the outlet opening.
The closure means is preferably configured in such a manner that optionally all outlet openings, no outlet openings or a selection of outlet openings can be closed.
One advantage of the device according to the invention is that a single closure means can be used to close a plurality of or all outlet openings. In this manner, the complexity of the device and thus also its susceptibility to errors is reduced as compared to the prior art. Owing to the low complexity of the device, the manufacturing costs for the device can, in turn, be reduced. Furthermore, a lower susceptibility to errors can be achieved, which is accompanied by an increased service life. A cost-effective use of the device can therefore be made possible.
In a device according to the invention, the closure means may be a slider that is preferably substantially plate shaped and has a thickness of between 0.1 mm and 200 mm inclusive, preferably between 0.1 mm and 1 mm inclusive, and particularly preferred between 0.2 mm and 0.5 mm inclusive. The slider may be configured to assume different positions relative to the nozzle body by means of translational movement parallel to a first direction and/or by means of rotational movement about an axis of rotation, with different numbers of outlet openings being fluidically connected to the activation medium inlet duct in different positions of the slider.
One advantage of a plate-shaped slider, in particular a plate-shaped slider having the thickness described above, is its flexibility. Such a slider allows, for example, an inclination of the nozzle body to be adjusted without having to change the inclination of the closure means and/or the inclination of a kinematics to shift/rotate the closure means. Similarly, the lower limit of the thickness of the slider is selected such that, despite its high flexibility, the slider is substantially rigid, i.e. is not damaged during closure.
In a device according to the invention, the slider may be configured to descend into a first end portion of the nozzle body. In the region of the first end portion, the nozzle body may comprise at least one guide member for guiding the slider, which, with respect to the first direction, takes up, for example, at least 10%, preferably at least 30% and particularly preferred at least 50% of the length of the slider, relative to the first direction. Such a guide member can prevent the slider from becoming stuck, in particular in the case of sliders with a high length-to-width ratio. The nozzle body and the closure means are preferably formed from the same or similar materials, for example steel. In this manner, jamming of the closure means, for example due to thermally induced expansion effects, can be prevented.
In a device according to the invention, the closure means may be arranged upstream of the outlet openings relative to the intended flow direction of the activation medium. In this arrangement, the flow of the activation medium can advantageously press the closure means against the outlet openings from the inside of the nozzle body, which can improve a sealing effect of the closure means. A smaller amount of the activation medium can thus escape due to leakage flows, which further improves the efficiency of the device. The advantages described above are enhanced if the closure means is a thin plate having, for example, the thickness described above.
If the closure means is arranged upstream of the outlet openings relative to the intended flow direction of the activation medium, the nozzle body may comprise an interior space, preferably precisely one interior space. This interior space may be fluidically connected to or brought into fluid connection with both the activation medium inlet duct and the outlet openings. A guide member for guiding the closure means may be formed in at least one section of the interior space. The guide member may be, for example, a groove or a rail. The guide member can make it possible to guide the closure means over a relatively long length. In this manner, the risk of the closure means becoming stuck can be reduced.
In a device according to the invention, the nozzle body may be formed of a plurality of interconnected components, the closure means being slidably arranged between at least two of the plurality of interconnected components. However, the nozzle body may also be configured as a one-part nozzle body. A one-part nozzle body may be produced, for example, by means of an additive manufacturing process. A multi-part nozzle body may have advantages in terms of manufacturing costs. The manufacturing of a one-part nozzle body by means of an additive manufacturing process may in particular be advantageous if the nozzle body has a complex geometry.
In a device according to the invention, the closure means may be arranged downstream of the outlet openings relative to the intended flow direction of the activation medium. In this manner, the accessibility of the closure means can be improved, for example. This can in particular facilitate service or replacement of the closure means.
The device described above may comprise a guide member for guiding the closure means on at least one side portion, preferably on two side portions of the activation medium outlet region. The guide member may be configured, for example, as a guide rail or guide groove. A guide member may be advantageous in the present context in that it can absorb the pressure applied to the closure means by the flow of the activation medium. This can counteract an undesirable elastic or plastic deformation of the closure means.
In a device according to the invention, the activation medium inlet duct may be formed in the first end portion. The first end portion is the portion of the nozzle body into which the slider descends. In one use of the device according to the invention, the first end portion is preferably located at an upper side of the device (relative to the direction of gravity). This arrangement advantageously makes it possible to prevent collisions in the installation space between workpiece-related and/or coating material-related contours and the activation medium inlet duct, the supply line as well as the closure means.
Alternatively or additionally, however, the activation medium inlet duct may also be formed in a second end portion that is different from the first end portion. The second end portion is preferably located opposite the first end portion or the activation medium outlet region. If the second end portion in which the activation medium inlet duct is formed is located opposite the activation medium outlet region, a uniform outflow of the activation medium from the outlet openings can be promoted.
In a device according to the invention, the first direction and a main axis of the activation medium inlet duct may form an angle of between 5° and 90° inclusive, preferably between 45° and 90° inclusive, and particularly preferred between 60° and 90° inclusive. Such an inclination of the activation medium inlet duct relative to the first direction, which is a displacement direction of the closure means, can be associated with advantages in terms of flow dynamics, for example.
In a device according to the invention, a first outlet opening may have a larger cross-section than a second outlet opening. The first outlet opening is preferably further away from the activation medium inlet duct than the second outlet opening. In this manner, it can be made possible to compensate for flow losses that can lead to a reduction in the corresponding outflow velocity, particularly in the case of large distances between the activation medium inlet duct and an outlet opening. The uniformity of the flow of the activation medium can therefore be promoted by different sized cross-sections of the outlet openings.
In a device according to the invention, the closure means may comprise closure means openings which are arranged in such a manner that at least one of the closure means openings can be brought into fluidic connection, at least in part, with at least one outlet opening by shifting the closure means. The closure means preferably comprises at least one closure means opening that has a larger opening cross-section than another closure means opening.
For example, a closure means described above may have elongated holes in a first portion and circular holes in a second portion. The width of the elongated holes may correspond to the diameter of the circular holes, and the length of the elongated holes may be greater than the diameter of the circular holes. In a first state, for example, a first group of outlet openings of the nozzle body may be fluidically connected to the elongated holes and a second group of outlet openings of the nozzle body may be fluidically connected to the circular holes of the closure means. In a second state, in which the closure means has been moved by displacement into a different position, the first group of outlet openings, for example, may still be fluidically connected to the elongated holes, but the second group of outlet openings may no longer be connected to the circular holes.
The device described above may have the advantage over other devices that the displacement path that must be travelled by the closure means in order to close or open a certain number of outlet openings can be reduced. Consequently, an actuator with a smaller size can be used to actuate the closure means, allowing a compact system layout to be achieved.
In a device according to the invention, the closure means may comprise at least one first portion in which a first number of closure means openings per area is provided. In addition, the closure means may comprise at least one second portion in which a second number of closure means openings per area are provided, the first number per area and the second number per area being different numbers per area.
Alternatively or additionally, in a device according to the invention, the nozzle body may comprise at least one first portion in which a first number of outlet openings per area is provided, and at least one second portion in which a second number of outlet openings per area is provided, the first number per area and the second number per area being different numbers per area. A number of openings per area is also referred to in the following as opening density.
A portion of the nozzle body and/or of the closure means that is located further away from the activation medium inlet duct preferably has a higher opening density (based on outlet openings and/or closure means openings) than a portion of the nozzle body and/or of the closure means that is located closer to the activation medium inlet duct. In this manner, it can be made possible, for example, to compensate for flow losses, and thus to achieve a substantially even volumetric flow of activation medium in different portions of the nozzle body (or the closure means). A nozzle body and/or a closure means preferably comprises a plurality of portions with a plurality of different opening densities (based on outlet openings and/or closure means openings). Particularly preferably, the opening density (based on outlet openings and/or closure means openings) increases gradually with the distance to the activation medium inlet duct.
In a device according to the invention, the nozzle body may comprise at least one interior space, preferably precisely one interior space, which is or can be brought into fluidic connection with the activation medium supply opening and with the outlet openings, said interior space preferably not being rotationally symmetrical. A rotationally symmetrical interior space may be a cylindrical bore, for example. A non-rotationally symmetrical interior space may have a cubic shape, for example. A non-rotationally symmetrical interior space may, for example, also have a substantially wedge-shaped or trapezoidal cross-section. By deviating from a rotationally symmetrical shape, it can be made possible to provide an interior space which is configured in a manner that is favourable in terms of flow and which can also be fluidically connected to and/or brought into fluid connection with a plurality of outlet openings.
If the nozzle body comprises an interior space, it may comprise at least one flow directing member configured to mix and/or direct the activation medium. The flow directing member is preferably configured to influence the flow of the activation medium in such a manner that the average outflow velocities of individual outlet openings fluidically connected to the activation medium inlet duct do not deviate from one another by more than 50%, preferably not more than 20% and particularly preferred not more than 5%. In this manner, it can be made possible to increase the uniformity of the flow and thus also the reproducibility of a method that can be carried out using the device.
A device according to the invention may comprise an adhesive application unit configured to apply adhesive to a coating material fed by the feed device and/or to a surface of a workpiece to be coated. An adhesive application unit may be a glue roller, for example. A device can therefore be provided that can be used for conventional edge coating by means of glue application and/or for edge coating with an activatable adhesive. The flexibility of the device can be increased in this manner.
A device according to the invention may be configured to rotate at least the activation device and/or the pressing device about at least one axis, preferably about a C axis. In the present case, a C axis is an axis perpendicular to a machining table, which the device according to the invention may further comprise. A device according to the invention may furthermore be configured to rotate at least the activation device and/or the pressing device about an F axis. In the present context, an F axis is an axis that is different to the C axis.
In a device according to the invention, the closure means may comprise a plurality of sectors that differ from one another. A first number of closure means openings may be formed in a first sector of the plurality of sectors and a second number of closure means openings may be formed in a second sector of the plurality of sectors. In such a device, closure means openings of the first sector or closure means openings of the second sector can be brought into fluidic connection, at least in parts, with the at least one outlet opening of the nozzle body by rotation and/or translation of the closure means. The first number and the second number are different numbers in this case. Alternatively or in addition to the different numbers of closure means openings in the different sectors, the first sector and the second sector may comprise closure means openings with different opening cross-sections.
The closure means described above is preferably configured to be substantially circular and comprises, for example, three, four, five or any other number of circular sectors, each having a different number of closure means openings to the other. For example, a first sector may have five closure means openings, a second sector may have ten closure means openings, a third sector may have 15 closure means openings, and so on. The closure means may furthermore comprise at least one sector in which no closure means openings are formed. The device may, for example, be configured in such a manner that, by rotating the circular closure means about a centre of a circle, closure means openings of the first sector, closure means openings of the second sector, or closure means openings of the third sector, etc., are selectively brought into fluidic connection with the at least one outlet opening of the nozzle body. The at least one outlet opening of the nozzle body may, for example, be precisely one outlet opening that is preferably configured to be substantially slit-shaped.
With the device described above, a simple and cost-effective arrangement can be provided that allows the outflow of the activation medium to be adapted to different coating materials and/or workpieces, even if installation space is limited.
In one use according to the invention of a device according to the invention, the nozzle body is moved relative to the closure means, the closure means being substantially stationary. The direction of movement of the nozzle body preferably has a component that is parallel to the direction of gravity. For example, the closure means may be a body that comprises a cavity. In this case, outlet openings of the nozzle body may be closed by a surface of the cavity when the nozzle body descends into the cavity. In such a use, the nozzle body may, for example, be guided through the cavity at its underside and thus have an increased degree of stability.
According to the invention, a method is provided for coating and/or activating workpieces preferably consisting at least in part of wood, wood materials, plastic, aluminium or the like. In a method according to the invention, a device for coating workpieces is used, preferably one of the devices described above. The device for coating workpieces comprises an activation device for activating an adhesive on a coating material fed by a feed device and/or for activating an adhesive on a surface of a workpiece to be coated. The activation device comprises at least one supply line for supplying an activation medium as well as a nozzle body having an activation medium inlet duct and an activation medium outlet region. The activation medium outlet region comprises at least one outlet opening, preferably at least two groups of outlet openings. The activation device further comprises precisely one closure means that is configured to close the outlet opening and/or individual outlet openings at least in parts. A method according to the invention comprises at least the following steps:
The step of actuating the closure means is preferably carried out in such a manner that all outlet openings of the nozzle body that are not opposite a coating material and/or a surface of a workpiece to be coated are partially or completely closed.
The same or comparable advantages to the device according to the invention described above can also be assigned to a method according to the invention. Furthermore, both the device according to the invention and the method according to the invention can make it possible to apply the activation medium only to a surface to be activated of a coating material and/or a workpiece to be coated. Consequently, damage to other surfaces of the workpiece and/or the coating material by the activation medium can be prevented.
The preferred embodiments of the present invention described below are merely examples and should not be seen as limiting. Identical reference numbers specified in different figures designate identical, corresponding or functionally similar elements.
The closure means 110 of the first embodiment as shown in
It is apparent from
Shown in
Shown in
By means of the variant of the second embodiment shown in
In a further variation of the second embodiment that is not shown, different sectors of a closure means 110 may have different numbers of closure means openings 111 with different opening cross-sections at least in parts.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2019 113 794.2 | May 2019 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2020/064095 | 5/20/2020 | WO | 00 |
