Blasting device

Abstract

The invention relates to an abrasive blasting device (10) for matting a workpiece using a suitable abrasive, which flows out of a cabin (12) of the device during the operation by means of a blasting nozzle under pressure. The invention is characterized in that the device has a workpiece holder (20) comprising a support frame (24) held in a rotary mount (22), on which holding means for fixing a workpiece are provided, which holding means are movably attached to the support frame so that when the support frame (24) is pivoted in the rotary mount (22), a workpiece to be processed can be rotated or pivoted about a selectable axis of rotation by adjusting the position of the respective holding means in the cabin space.

Description

[0001] The present invention relates to the field of surface treatment using blasting media, also known under the general term "sandblasting." Such a process serves to clean and mat surfaces, particularly metal surfaces. The process thus fulfills a dual function: it cleans the surfaces and also roughens them for subsequent painting or coating. The blasting effect is achieved by blasting media, such as corundum, garnet sand, slag, cast steel, or glass beads, which impact the surface to be treated at high speed. Thus, the surface structure can be determined by the choice of blasting media used, with the degree of cleaning also being determined by the subsequent surface protection required. During the blasting process, a powerful air jet is generated and used to accelerate the blasting media.The required air pressure is generated by special compressors, and the powdered or granular blasting media can be used either dry or mixed with water from a collection container. For example, a sand-air mixture is blasted at high speed onto the surface in question via a hose and nozzle system. Surface particles are dislodged and subsequently removed by the abrasive blasting action. This thoroughly cleans surfaces of contaminants, rust, paint, or scale. Depending on the duration of the process, the choice of blasting media, and the pressure applied, different levels of cleaning can be achieved.

[0002] Painting a surface usually requires mechanical grinding to achieve a roughness depth and thus good paint adhesion. This process is often referred to as "matting" the surface. Here, too, different roughness depths can be achieved for the desired matting, depending on the process duration, the choice of blasting media, and the pressure applied.

[0003] Due to the above aspects, sandblasting technology is particularly popular in the automotive industry for work pieces or components that are to be painted. Such parts can sometimes be very large. For the conventional matting of such automotive parts, such as a bumper, in a blasting process, these are usually blasted in a large, walk-in booth on skids. During blasting, the kinetic energy of the particles creates a large dust load on all sides, which can then cause unwanted contamination in the downstream painting process. Therefore, a closed booth is necessary for blasting so that the blasting material, dust, and other contaminants can be extracted and prevented from escaping to the outside.The booth size must be large enough to allow the operator to walk around the bumper, positioned centrally in the booth, to work on its entire length ("from ear to ear") as well as from the top and bottom. This is problematic because the distance between the blasting nozzle and the workpiece should generally be between 20 and 50 cm at all times. A car bumper can also be up to 200 cm wide. This makes conventional booths enormous and takes up a lot of space in the paint shop. As booth size increases, the extraction system, substrate return, substrate preparation, filter units, and much more of the system technology must be dimensioned accordingly. This, in turn, requires large air volumes to operate the system, which is associated with high energy consumption. In addition, the operator must wear a protective suit including a helmet with breathing air.This is time-consuming in terms of preparation time until the system is ready for operation. After all, such walk-in blasting cabinets require large doors to accommodate large workpieces. Due to the large air volumes within the blasting cabinets, the extraction system also requires a certain amount of time to sufficiently minimize the dust load inside. If the doors are opened beforehand, blasting media and dust can escape into the workshop, exacerbating the contamination problem.

[0004] The invention is therefore based on the object of improving the conventional blasting cabinets described above, in particular for painting preparation and in particular for elongated workpieces, such as motor vehicle bumpers, fenders, sills, aluminum rims or other medium-sized workpieces, with the associated blasting media processes.

[0005] This object is achieved by a device according to claim 1. Advantageous embodiments emerge from the respective subclaims.

[0006] The starting point of the task is therefore to realize an almost complete irradiation of different workpieces in a blasting cabin that is as small as possible, whereby a suitable distance between the blasting nozzle and the workpiece surface can be continuously maintained over the entire surface of the workpiece to be processed.

[0007] The basic concept of the invention can be formulated as a blasting device for cleaning and / or matting a workpiece. A workpiece holder is provided in the device's booth to hold the workpiece. This holder can also be used to move the workpiece within the booth. This holder allows the workpiece to be moved within the booth in such a way that, on the one hand, the entire surface of the workpiece to be treated is accessible to the blasting nozzle, and, on the other hand, the appropriate distance between the blasting nozzle and the surface currently being treated can be maintained. The phrase "entire surface to be treated" does not necessarily refer to the entire surface of the workpiece, but rather only to the portion of the surface to be matted. A workpiece, such as a bumper, cannot be matted in its entirety because the surface to be painted often only comprises the outward-facing surface of the bumper.

[0008] According to the invention, the workpiece holder is mounted in the booth so that it can rotate along at least one axis of rotation. A workpiece fixed in or on the workpiece holder can thus be rotated or pivoted during processing, thereby maximizing the surface area accessible for processing relative to an unchanged nozzle position of the blasting device.

[0009] When a workpiece is rotated in the blasting cabinet, an envelope curve or "envelope" is generated, known from mathematics, which reflects an imaginary rotating body. According to the invention, this rotating body should be kept as small as possible in order to achieve a fundamentally small cabinet size. To this end, the invention advantageously provides that the holding parts of the workpiece holder, on which the workpiece is held, are adjustable in position, allowing the workpiece to rotate around an almost freely selectable axis of rotation centrally in the cabinet.

[0010] The device according to the invention is characterized in that the device has a workpiece holder which comprises a support frame held in a rotary holder, on which holding means for fixing a workpiece are provided, which holding means are displaceably attached to the support frame so that, when the support frame is pivoted in the rotary holder, a workpiece to be machined can be rotated or pivoted about the selectable axis of rotation by adjusting the position of the respective holding means in the booth space. In other words, the workpiece holder can be adjusted so that, for example, the workpiece to be machined can be placed with its longitudinal axis parallel to the longitudinal axis of the booth, so that during rotation the workpiece is rotated about its own longitudinal axis as centrally as possible in the booth space.

[0011] For this purpose, according to an advantageous embodiment, a respective rotary mount is arranged at the lateral ends of the blasting device - i.e., at the ends of the cabin's longitudinal axis - within the cabin, on the side walls thereof or in the vicinity thereof. The workpiece holder is mounted in these rotary mounts. The workpiece holder itself, mounted on the rotary mounts, comprises a support frame that makes it possible to fix a workpiece to be machined with its longitudinal axis as coaxial as possible between the rotary mount points. With the rotation of the workpiece holder and the support frame, the workpiece itself can then be rotated with a minimal envelope curve, i.e., with a minimal area covered by the rotation.This creates an advantageous prerequisite for maintaining a nearly uniform distance between the blasting nozzle and the workpiece surface to be treated, even when the position of the blasting nozzle remains unchanged within the booth. It also allows for minimizing the dimensions of the blasting booth. This distance between the blasting nozzle and the surface to be treated remains constant even when the blasting nozzle is moved linearly along this longitudinal axis through the booth space.

[0012] According to an advantageous embodiment, the support frame of the workpiece holder held on the rotary mounts has support arms that project radially from the rotary mounts and from the rotation axis, which are connected to a cross member running the length of the cabin. On the cross member itself, a radial support for a fixing frame is provided approximately centrally, approximately corresponding to the length of the support arms. The fixing frame has at least one saddle support held in a slide guide and at least one clamping arm held in a slide guide. Alternatively, radial supports of the support frame can be provided on the cross member of the support frame, which are spaced apart from one another, arranged approximately centrally together and each approximately corresponding to the length of the support arms, wherein the at least one positionable saddle support and the at least one positionable clamping arm of the support frame are held by a gripper via at least one of the radial supports.

[0013] The support arms are positioned as far out as possible on the sides of the blasting cabin at its longitudinal ends so that the workpiece can be completely fixed between these support arms. This means that a workpiece that is set in rotation is not covered by the support arms during processing and thus the blasting process carried out between the support arms is not disturbed.

[0014] The saddle support serves to initially place the workpiece upon introduction into the blasting cabinet, and then to secure it with the fixing means provided on the clamping arm. According to an advantageous embodiment, at least two saddle supports and at least two clamping arms are provided along the cross member, each of which is adjustable in at least two spatial directions in its slide guides. This enables reliable fixation of any three-dimensional workpieces of various shapes, such that they are securely held during rotation in the blasting cabinet. Alternatively, according to an advantageous embodiment, ball joints can also be provided, with which a respective saddle support or a respective clamping arm can be freely positioned in three-dimensional space.

[0015] Advantageously, the fixing means on the clamping arms are spring-loaded clamping grippers. Furthermore, it is advantageous to provide free positioning in three spatial dimensions for the clamping grippers on the clamping arms. For this purpose, the clamping arms, which can be moved in slides, can be combined with grippers mounted on ball joints.

[0016] With the above design concept, the booth size could be significantly reduced compared to conventional booths. Even large workpieces, such as car bumpers, can be blasted across the entire surface to be treated, including any undercuts in the workpiece contour. Due to the compact size of the device and its enclosure for the workpiece, the amount of air required for the blasting process and also the amount of particles required are lower. This translates into advantageous energy savings for the extraction system, the filter system, and for the substrate recirculation. The smaller air volume within the system can therefore be extracted and cleaned more quickly, which also advantageously reduces contamination from dust and other contaminants generated during the blasting process.

[0017] The device according to the invention allows the worker to move outside the device over the entire length of the workpieces, such as a motor vehicle bumper, without interrupting the blasting process in the machine body, while being able to guide the blasting nozzle. The matting can be carried out over its entire length ("from ear to ear") without having to remove or move his hands from the blasting cabinet. The invention enables this process through the rotation and adjustment of the saddle supports and clamping arms of the workpiece holder, even with curved workpieces such as motor vehicle bumpers. The workpiece holder is thus designed to accommodate the respective workpiece in such a way that the workpiece can be rotated coaxially and centrally to the axis connection of the lateral pivot points, so that the envelope curve, i.e. the space required when rotating the workpieces, is as small as possible.covers as small an area as possible.

[0018] In an advantageous embodiment, the workpiece holder has a rotation stop. When the workpiece holder rotates, this rotates with it and represents the maximum envelope. When fixing the workpiece in the workpiece holder, care must be taken to ensure that the workpiece does not protrude beyond the rotation stop. The workpiece is therefore fixed in the same plane as the rotation stop. This means that when the workpiece is clamped, it is already clear that the envelope curve resulting from the rotation of the workpiece is smaller than the maximum envelope curve of the rotation stop. In other words, it is already clear before the workpiece holder and workpiece begin to rotate that the workpiece will not strike any fixture element in the cabin at any point. The rotation stop therefore prevents the workpiece from uncontrollably touching the machine body or from hitting it.can get stuck.

[0019] According to an alternative advantageous embodiment for holding the workpiece, two structural units of the support frame are arranged on the end face of an alternatively designed cross member which is held so as to be rotatable about its longitudinal axis. The cross member is therefore not pivoted about an external axis, but is held so as to be rotatable coaxially to its longitudinal axis. For this purpose of coaxial rotation, the cross member is held in two spaced-apart radial arms in pivot bearings of rotary mounts. The radial arms are arranged on the inside, i.e. between the end saddle supports which are on the outside in relation to the workpiece holder. The support arms should be arranged as close to one another as possible so that the cross member can be held stably in its axial position by the support arms, but that there is also a sufficient distance to the end support frames.By means of the distance thus obtained between a respective support frame and its support arm, it is achieved that a workpiece to be fixed can be held well outside the support arm and the workpiece set in rotation does not come into contact with the respective support arm during processing and the blasting process carried out between the support arms is thus not disturbed.

[0020] This rotation is also advantageously achieved by an electric motor, whose output shaft engages the cross member via a drive belt using a taper bushing and can set the cross member in rotation by actuating the electric motor.

[0021] According to an advantageous embodiment, the seat posts can be provided as foam holders or foam supports.

[0022] Advantageously, the workpiece holder according to the invention can be provided with additional adapters in order to be able to clamp and hold the spectrum of workpieces, such as rims, fenders, sills, but also other workpieces for industrial use, in order to subject them to almost all-round processing.

[0023] The workpiece holder can advantageously be rotated by means of an electric motor in both directions of rotation relative to the longitudinal axis of the device.

[0024] According to an advantageous embodiment, the workpiece carrier is mounted in a tiltable manner, with the respective end positions of the tilting process defining a "processing position" and a "loading position." In practice, this means that the workpiece holder is moved to a forward position facing the booth opening for loading, in order to ensure good access for positioning and securing a workpiece. Before blasting, the workpiece holder is then tilted backward into the "processing position," thereby achieving the necessary distance between the workpiece and the blasting media nozzle. According to an advantageous embodiment, this tilting process is designed in such a way that the rotary mounts, in which the workpiece holder is held on both sides, are arranged in radial arms, the opposite ends of which are arranged in the floor area of ​​the blasting booth with pivot bearings.This allows the rotary mounts to be pivoted along a circular arc in the blasting booth. This pivoting movement can advantageously be limited by a stop, which defines the two respective end positions of the tilting process: the aforementioned "processing position" and "loading position."

[0025] The invention advantageously provides that the tilting device can be operated automatically or manually using a push button. For this purpose, at least one corresponding pneumatic cylinder is provided, which automatically moves to the front loading position when the machine cover is opened. When the cover is closed, the pneumatic cylinder automatically moves the workpiece holder to the processing position, for example, by pressing a button.

[0026] According to an advantageous embodiment, a cabin lid of the device is provided, which comprises a continuous viewing window along the longitudinal direction of the device, so that a worker has a view of the workpiece from any position along the longitudinal axis of the device. Even more advantageous is a cabin lid that also extends over the side walls of the device. A viewing window mounted therein then extends equally over the side walls of the cabin lid.

[0027] The cabin lid can be pivoted upwards as a single component, allowing complete access to the cabin interior from the front and sides. This allows for quick and easy loading and unloading of a workpiece. Pneumatic cylinders or gas pressure dampers mounted on the respective side wall of the cabin lid can advantageously assist in raising and lowering the opening lid.

[0028] According to a further advantageous embodiment, an ergonomically positioned hand grip is provided in the booth lid for guiding a jet nozzle from outside the device and along the entire longitudinal axis of the device and over the side walls of the booth lid along the viewing window. Such a hand grip can advantageously be provided with a brush guard to protect against escaping matting substrate.

[0029] The nozzle is guided by a special device that allows the operator to grasp the blasting nozzle, similar to a paint spray gun, and thus precisely control it. The blasting process is advantageously activated via a safety-monitored hand lever on this device. An operator outside the blasting cabinet can thus guide the blasting nozzle gun inside the blasting cabinet with one hand by using the manual intervention described above.

[0030] According to an advantageous embodiment, an axis system is located above the device. This allows, among other things, the further development of an automated procedure. The invention provides that, instead of manual blasting by an operator, automated processing can also be performed by a robot, thus allowing the advantages of the existing rotating device of the workpiece holder to be used as an automation axis. This embodiment is complemented in an advantageous further development by a similarly automated blasting nozzle in the cabin. Ultimately, the blasting process can thus be carried out fully automatically using an industrial robot or an axis system.

[0031] According to a further advantageous embodiment, the device according to the invention has a collecting tray for the blasting media, which opens into a flat conveyor system. This allows the blasting media to be returned and reused in a targeted manner. In an advantageous embodiment, the collecting tray has a surface that slopes downwards at an angle, allowing the matting substrate to be automatically conveyed to the flat conveyor below by gravity.

[0032] Furthermore, according to an advantageous embodiment, the invention provides for suitable maintenance hatches that allow access to system components from the side and rear of the device. This allows the device to be positioned directly against a wall—except for machine maintenance. This further saves space during installation.

[0033] Overall, the device according to the invention is not only particularly suitable for matting motor vehicle bumpers, as described above. Rather, the invention also generally encompasses the use of this system for preparing elongated components, such as motor vehicle sills, for painting. Furthermore, the system according to the invention can also be used to mat other add-on components, such as aluminum rims and other vehicle add-on parts. However, many other carbon components and other industrial applications are also conceivable. Finally, the term "workpiece to be painted" used in the context of the invention includes not only sheet metal and aluminum components, but also plastic components, such as fenders and spoilers.

[0034] The system is designed to be ideally suited for the use of an eddy current rotation process for microabrasive matting of the surface in question. The microabrasive eddy current process leads to significantly improved paint adhesion during the subsequent repainting. This is particularly true in areas of bumpers or narrow gaps between aluminum rims that are difficult or even impossible to access manually. This is achieved through a significantly stronger bond between the new paint layer and the treated substrate. Tests with the paint cross-cut process have demonstrated this. The microabrasive eddy current process and the resulting improved paint adhesion also achieve significantly better corrosion protection. The microabrasive eddy current process has a swirl body in front of the nozzle inlet, for example, with four angled holes that are advantageously inclined at an angle of 12° to 20° (degrees) to the flow axis.The microjet particles flow at an angle through the aforementioned angled holes into the nozzle. The nozzle is conically widened towards the outlet side, so that when compressed air is applied, a single, widened, and additionally rotating eddy current cone is created with optimal particle distribution across the entire cross-section of the rotating jet cone. The resulting rotational effect of the air flow guides the microfine microjet particles almost tangentially over the surface to be matted. This reduces the negative impact of the blasting medium and prevents negative processing marks on the paint or coating surface. Overall, a uniformly matted surface is achieved, ensuring optimal mechanical adhesion for the new coating. The nozzle can be a Venturi or Laval nozzle type, with a swirl element attachment installed upstream.A favorable air pressure is approximately 1.5–2 bar. The nozzle distance from the object varies depending on the prevailing air pressure, but is generally preferred between 20–50 cm. Particles with a hardness of 4–10 (Moh's scale) are advantageously used as the blasting medium. The grain shape is preferably angular or crystalline. Preferred grain sizes are 50–200. µ m.

[0035] In the following, the invention will be described in more detail in an embodiment as shown in the accompanying drawings.

[0036] The drawings show Fig. 1 shows a blasting device according to the invention in side and front views, as well as in plan view; and Fig. 2 shows a workpiece holder according to the invention in front and side views, as well as in plan view. Fig. 3 shows another workpiece holder according to the invention in front and side views, as well as in plan view.

[0037] The Fig. 1 The dimensions of the blasting device 10 shown here are clearly visible in the illustration with the operator. Top left in Fig. 1 the blasting device 10 is shown with the booth lid 14 half open. However, the booth lid can be pivoted even further upwards, so that full access to the interior of the booth is also possible from above. The booth lid extends over the entire front longitudinal side of the blasting device and also over its respective side walls. The technical components of the blasting device are attached to the rear housing wall. These include, among other things, an extraction system 40 and a filter system 42. A viewing window 16 is provided in the booth lid 14, which allows a view into the booth space even when the booth lid is closed. This viewing window 16 advantageously runs the entire length of the blasting device and further over the angled side walls of the booth lid.

[0038] Below the viewing window 16 is a hand grip 18. This runs parallel to the viewing window over the entire length of the blasting device and also extends into the angled side walls of the booth lid 14. The hand grip 18 includes a brush barrier around its edge, which prevents the matting agent from escaping. Using the hand grip 18, an operator can guide a blasting agent nozzle into the booth chamber with the booth lid 14 closed.

[0039] The blasting nozzle (not shown) itself is integrated into a nozzle gun (not shown), which has a hose connection for supplying the blasting media at one end, while the nozzle is located opposite at the other end. The blasting media outlet is activated via a pistol-like actuating lever. When the eddy current process is used, a swirl body with, for example, four angled holes is placed in front of the nozzle inlet. These holes are advantageously inclined at an angle of 12° to 20° (degrees) to the flow axis. This causes the microjet particles to flow into the nozzle at an angle through these angled holes. The nozzle is then conically widened towards the outlet side, so that when compressed air is applied, a single, widened and additionally rotating eddy current cone is created with optimal particle distribution across the entire cross-section of the rotating blasting cone.The resulting rotational effect of the air stream guides the microfine microjet particles almost tangentially over the surface to be matted. This reduces the negative impact of the blasting medium and prevents negative processing marks on the paint or coating surface. Overall, a uniformly matted surface is achieved, ensuring optimal mechanical adhesion for the new coating. A Venturi or Laval nozzle can be used as the nozzle. A favorable air pressure is approximately 1.5–2 bar. The nozzle distance from the object varies depending on the prevailing air pressure, but is generally preferred to be 20–50 cm. Particles with a hardness of 4–10 (Moh's scale) are advantageously used as the blasting medium. The grain shape is advantageously angular or crystalline. Preferred grain sizes are 50–200 pm.

[0040] Fig. 2 shows the workpiece holder 20: This is arranged in the interior of the booth. The workpiece holder 20 has a support frame 24 for the workpiece to be matted. The support frame 24 includes two saddle supports 32 and two clamping arms 34. A workpiece (not shown) can be placed on the saddle supports 32 and subsequently secured by means of the grippers 36 attached to the clamping arms. The grippers are advantageously spring-loaded and have rubberized stops to hold the workpiece gently. The construction consisting of saddle supports 32 and clamping arms 34 is held on the cross member 28 via a radial support 30. Alternatively, radial supports 30 of the support frame 24 can be provided on the cross member 28 of the support frame 24, spaced apart from one another, arranged approximately centrally and each approximately corresponding to the length of the support arms 26 (not shown).Both the seat supports 32 and the clamping arms 34 are held displaceably by means of slide guides 38. A single seat support or a single gripper arm can be moved in two directions, allowing the end pieces—either a respective gripper 36 or a respective cushion of a seat support 32—to be positioned as desired in a plane. The clamping arms 34, which are held displaceably by means of slide guides 38, with the end pieces in the form of the gripper 36 or the cushion of the seat support 32, can be arranged directly on one or more spaced-apart radial supports 30 (not shown). This allows the seat supports and the clamping arms to be adjusted to the respective workpiece in order to hold it firmly and immobilely on the support frame 24. This also applies when the support frame 24 rotates.

[0041] During rotation, the support frame 24 rotates around two rotary mounts 22, which are located at the respective lateral ends of the cabin. An electric motor 44 is provided on one of the rotary mounts, which is shown on the left in the figure as an example, and which rotates the support frame 24 when activated. Two support arms 26 protrude from each of the two rotary mounts 22 and are connected to one another via a cross member 28. When the support frame 24 rotates, the cross member 28 and its two support arms 26 create a rotary cylinder that forms an envelope. As long as the cross member 28 represents the greatest radial distance from the two rotary mounts 22, a workpiece held in the rotary cylinder is protected from getting caught on or hitting a component of the blast cabin. The cross member thus forms a rotation stop for the workpiece.In this respect, when clamping the workpiece to the support frame 24, care must be taken to ensure that the workpiece does not protrude beyond the cross member 28 in the plane formed by the rotary holders 22 and the cross member 28.

[0042] The two support arms 26 are pivotally mounted on radial arms 46, which are positioned as close as possible to the side walls of the booth. This allows long workpieces, such as car bumpers, to be accommodated over the entire length of the blasting booth.

[0043] As can be seen from the side views in the Fig. 2 As can be seen, the radial arms 46 are themselves mounted in respective pivot bearings 48. This allows the entire workpiece holder to be tilted within the cabin interior. The respective end position of the tilting process defines a "processing position" and a "loading position." In practice, this means that the workpiece holder is moved to a front position facing the cabin opening for loading, in order to provide good access for positioning and securing a workpiece. Before blasting, the workpiece holder is then tilted backward into the "processing position," whereby the necessary distance between the workpiece and the blasting media nozzle can be achieved. This pivoting movement is limited by a stop, which defines the two respective end positions of the tilting process: the aforementioned "processing position" and "loading position."

[0044] Fig. 3 shows an alternative workpiece holder 20 to that of Fig. 2 ., which is also located inside the cabin. The workpiece holder 20 of the Fig. 3 is compared to that of Fig. 2 constructed more compactly, in that here the radial arms 46 are arranged on the inside, i.e. between the now outer seat posts 32. In this embodiment, the cross member 28 is mounted in the respective radial arm 46 in rotary receptacles 22 so as to rotate relative to the radial arms 46. A workpiece (not shown) can be placed on the seat posts 32 and subsequently secured by means of the grippers 36 attached to the respective clamping arms. The grippers 36 are advantageously spring-loaded and have rubberized stops in order to hold the workpiece gently. Both the seat posts 32 and the clamping arms 34 are held displaceably by means of slide guides 38. A displacement of an individual seat post or an individual gripper arm can take place in two directions, whereby the end pieces - i.e. either a respective gripper 36 or a respective cushion of a seat post 32 - can be positioned as desired in a plane.This allows the saddle supports and clamping arms to be adjusted to the respective workpiece to hold it firmly and immobilely on the support frame 24. This also applies when the cross member 28 rotates.

[0045] The rotation of the cross member 28 is achieved by an electric motor 44, whose output shaft engages the cross member 28 via a belt drive and can set it in rotation by actuating the electric motor. In the embodiment shown, the electric motor 44 is attached to one of the radial arms 46 toward the inside of the workpiece holder 20.

[0046] The Fig. 3 The saddle supports shown can alternatively also be provided in the form of a respective foam holder. The workpiece holder 20, as before, has a support frame 24 for the workpiece to be matted.

[0047] As can be seen from the side views in the Fig. 3As can be seen again, the radial arms 46 are in turn mounted in respective pivot bearings 48. This enables the entire workpiece holder to be tilted within the cabin. The respective end position of the tilting process defines a "processing position" and a "loading position." In practice, this means that the workpiece holder is moved to a front position facing the cabin opening for loading, in order to provide good access for positioning and securing a workpiece. Before blasting, the workpiece holder is then tilted backward into the "processing position," whereby the necessary distance between the workpiece and the blasting agent nozzle can be achieved. This pivoting movement can be limited by a stop, which defines the two respective end positions of the tilting process, the aforementioned "processing position" and "loading position."

[0048] The features of the invention described with reference to the illustrated embodiments may also be present in other embodiments of the invention, unless otherwise stated or prohibited by technical reasons. List of reference symbols:

[0049] 10 Blasting media device 12 Cabin 14 Cabin cover 16 Viewing window 18 Hand grip 20 Workpiece holder 22 Rotating holder 24 Support frame 26 Support arm 28 Cross beam 30 Radial beam 32 Saddle support 34 Clamping arm 36 Gripper 38 Slide guide 40 Extraction system 42 Filter system 44 Electric motor 46 Radial arm 48 Rotating bearing of a radial arm 50 Taper bushing 52 Drive belt

Claims

1. Blasting device (10) for matting a workpiece by means of a suitable blasting medium which flows out during the operation by pressurisation by means of a blasting nozzle in a cabin (12) of the device, characterized in that the device has a workpiece holder (20) which comprises a support frame (24) held in a rotary holder (22), on which support frame holding means for fixing a workpiece are provided, which holding means are displaceably attached to the support frame so that when the support frame (24) is pivoted in the rotary holder (22), a workpiece to be machined can be rotated or pivoted about a selectable axis of rotation by adjusting the position of the respective holding means in the cabin space.

2. Blasting device (10) according to claim 1, characterized in thatthe support frame (24) of the workpiece holder (20), which is held on rotary holders (22), has support arms (26) which project radially from the axis of rotation and are connected to a cross member (28) of the support frame, on which a radial support (30) of the support frame is provided approximately centrally, corresponding approximately to the length of the support arms (26), via which at least one positionable saddle support (32) and at least one positionable clamping arm (34) of the support frame are held by a gripper (36).

3. Blasting device (10) according to claim 1, characterized in thatthe support frame (24) of the workpiece holder (20), which is held on rotary holders (22), has support arms (26) which project radially from the axis of rotation and are connected to a cross member (28) of the support frame, on which radial supports (30) of the support frame are provided which are spaced apart from one another and arranged approximately centrally together and each approximately correspond to the length of the support arms (26), wherein at least one positionable saddle support (32) and at least one positionable clamping arm (34) of the support frame are held by a gripper (36) via at least one of the radial supports (30).

4. Blasting device (10) according to one of the preceding claims, characterized in that the positioning of the seat post (32) and the clamping arm (34) is carried out by means of the respective slide guide (38).

5. Blasting device (10) according to claim 4, characterized in thatthe slide guides (38) for the seat post (32) and for the clamping arm (34) provide a respective three-dimensional positioning in the cabin space.

6. Blasting device (10) according to one of the preceding claims, characterized in that the supporting frame (24) can be moved in the rotary receptacles (22) by means of an electric motor.

7. Blasting device (10) according to one of the preceding claims, characterized in that the support frame (24) is held on radial arms (46), wherein the radial arms (46) are held in pivot bearings (48) at the opposite end of the rotary receptacles (22), so that pivoting of the radial arms enables tilting of the support frame (24) over a circular path sector in the cabin space.

8. Blasting device (10) according to one of the preceding claims, characterized in that the jet nozzle is arranged on a manually operated nozzle gun which can be guided into the cabin space by an operator located outside the cabin.

9. Blasting device (10) according to one of the preceding claims, characterized in that an industrial robot rotates the workpiece holder and / or guides the blasting nozzle.

10. Blasting device (10) according to one of claims 1, 4, 5, 6, 8 and 9 characterized in that a cross member (28) is fixedly connected to the support frame, wherein the cross member (28) is rotatably held in pivot bearings of pivot receptacles of radial arms, and the support frame has at least one positionable saddle support (32) and at least one positionable clamping arm (34) with a gripper.

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