EP1721705B1 - Device for abrasive blasting of workpieces - Google Patents

Abstract

The device has a chamber (2) with a jet chamber (2A) and an opening (4). A jet pipe unit with a jet pipe (6) is connected into the first opening of the jet chamber and a container (8) holds the blast material. The container is fastened to the jet pipe unit (5) or fastened, in such a manner, that the blast material can run freely into an intake (9) of the jet pipe unit.

Description

The present invention relates to a device for abrasive blasting, in particular for sandblasting of workpieces, in particular of smaller workpieces, for example in the hobby sector (model making) or for carrying out blasting operations on smaller, limited areas of larger surfaces, for example in motor vehicles.

Devices for abrasive blasting are known, for example, as sandblasting devices. These previously known devices generally consist of a blasting agent container and a lance. The blasting agent, such as quartz sand is transported by a compressor under pressure through a hose from the blasting agent container to the lance and thus directed to a workpiece to be machined by means of a compressor.

These known devices are relatively expensive, in particular because of the necessity of the compressor, so that their use for occasional work such as in the private or hobby sector, for example in model making is uneconomical.

In addition, these devices are generally relatively large and usually not operable with low operating pressures, so that very small components or small areas can hardly be satisfactorily processed. Another disadvantage is that in these devices blasting material in large quantities enters the environment, which prohibits use in residential areas, or the blasting agent can be collected only by using an additional closed cabin, whereby the system but further increased and more expensive ,

Finally, in the known devices, a limitation of the area to be processed only by masking or masking the remaining surfaces possible. However, the masking results in a relatively sharp transition occurring at the boundary to the blasted area, which must be smoothed, for example, only by applying and repeatedly sanding a filler or leveling compound for subsequent painting.

It is also known from the DE 19614555 an apparatus and a method for abrasive blasting of workpieces, wherein a blasting agent is conveyed by vacuum, which is generated by evacuating a chamber, from a storage container via a hose and a spray lance into the chamber and blasted onto a small workpiece located in the chamber , The present invention is based on the known from this prior art principle of action. Disadvantage of this prior art is the limitation of the working and movement range on the hose length and limited due to the hose to be carried freedom of movement and a limitation on the size of the workpieces, provided that they are to be introduced into the chamber.

From the DE 10257241 A1 a device for abrasive blasting of workpieces is known, on which the preamble of claim 1 is based. This device has a jet lance, which has an opening for connecting a device for sucking air from the jet lance, such as an industrial vacuum cleaner, as well as located at the front end further opening for placement on a surface of a workpiece to be machined. At the rear end of the jet lance, a suction opening is provided, into which a hose feed line to an external blasting medium container is inserted so that an annular gap for sucking atmospheric air remains. The blasting medium is sucked from the blasting agent container through the hose feed line into the blasting lance, when a negative pressure is generated there during operation by sucking off the air. The blasting medium is guided and accelerated within the blasting lance by a mixing tube firmly integrated into the blasting lance.

The invention is based on the principle described above and its object is to bring a detail improved apparatus for abrasive blasting of workpieces in proposal, which can be realized inexpensively and is easier to handle.

According to a further aspect of the invention, the device should also be able to process small areas on large areas.

This device has a device for abrasive blasting of workpieces according to protection claim 1. This device has a (evakuierbare in operation) chamber having a first opening, a nozzle unit with a jet pipe, which is insertable into the chamber via the first opening, and a container for receiving blasting agent, wherein the container for receiving is attached or attachable by blasting agent to the nozzle unit, such that the blasting agent can leak from the container freely into an inlet of the nozzle unit.

The device according to the invention has the advantage that due to the fixed connection between the blasting agent container and the jet tube unit, a hose is completely eliminated. Since the blasting agent is conveyed by the negative pressure in the chamber from the container through the jet pipe into the chamber an operator only has to handle the jet pipe unit and can therefore move relatively freely. This also makes it possible to process small areas on large areas, e.g. in the automotive sector with the repair of body parts or in inaccessible areas easily possible.

The chamber has a second opening, with which the chamber can be placed on a workpiece to be machined. Preferably, an elastic seal is provided for sealing the gap between the outer periphery of the second opening and the workpiece. In this embodiment, the local editing of small areas on larger areas is very easy, because the area to be radiated is limited by the size of the second opening and the chamber or the opening can be easily placed by hand on the respective location to be machined. The jet tube guided through the first opening in the chamber is movable within the chamber and can be directed to the area enclosed by the second opening.

Further advantageous embodiments of the device according to the invention are specified in the dependent claims.

• Fig. 1 eine perspektivische Darstellung der erfindungsgemäßen Vorrichtung von vorne und oben betrachtet,
• Fig. 2 eine perspektivische Darstellung der erfindungsgemäßen Vorrichtung von hinten und unten betrachtet, und
• Fig. 3 eine teilweise geschnittene Darstellung der Strahlrohreinheit der erfindungsgemäßen Vorrichtung in Seitenansicht.

In the following the invention will be described in detail with reference to the accompanying drawings. Show:

• Fig. 1 a perspective view of the device according to the invention viewed from the front and top,
• Fig. 2 a perspective view of the device according to the invention viewed from behind and below, and
• Fig. 3 a partially sectioned view of the nozzle unit of the device according to the invention in side view.

In the Fig. 1 illustrated embodiment of the apparatus for abrasive blasting of workpieces basically has two components: a chamber unit with evacuated in operation chamber unit 2 with an access opening 4 and a jet pipe unit 5 with a jet pipe 6, which is inserted via the access opening 4 in the chamber unit 2. At the access opening 4 for the jet pipe 6, a seal 4A is provided to seal the access opening with respect to the jet pipe 6 when it is inserted into the access opening 4 and to allow a rotation and tilting movement of the jet pipe and a movement in the longitudinal direction. Preferably, an elastic membrane made of plastic or rubber is used as a seal.

The jet tube unit 5 has a container 8 for receiving blasting agent, wherein the blasting agent container 8 is preferably detachably fastened or attachable to the nozzle unit, such that the blasting agent is released from the container 8, i. essentially can only leak under the action of gravity in an inlet 9 on the jet pipe unit 5. As a blasting agent, quartz sand or any other suitable fine-grained substance can be used.

The inlet 9 is located at the upper rear end of a housing 7, which is formed on the outer contour so that it supports the handling by an operator as a handle. At the rear end of the housing 7 of the jet pipe unit 5 is an air inlet opening 11, which communicates with the emerging at the front end of the housing 7 elongate jet pipe 6 and the inlet 9 for the blasting agent. This is especially clear in Fig. 3 which shows a pipe connector 12 arranged in the housing 7, which connects said openings and the jet pipe to one another.

The jet pipe unit 5 has in the region of the inlet a receptacle 8 B, via which the container 8, are provided on the corresponding counterparts in the form of struts 8C, releasably supported on the nozzle unit 5 so that a spout 13 of the container 8 in a predetermined distance above the inlet 9 is located. The inlet is further expanded in diameter relative to the outlet of the container, formed funnel-shaped inside and provided with a circumferential raised collar or edge to reliably guide the blasting agent despite the distance between the outlet and inlet into the connector and to prevent leakage.

To adjust and regulate the amount of blasting material passing through the outlet 13, a metering device 10 is preferably provided on the container 8, which can selectively change or close the cross section of the outlet opening in a manner known per se. In a variant not shown, the metering device may comprise a lever accessible to and actuatable by a user, e.g. is urged and urged by a spring into a closed position, in which the outlet opening is closed when not in use and only by applying a force and as long as it acts is opened. Further, the container is closed at its upper end by a removable lid 8A, via which the filling takes place.

In order to ensure a free discharge of the blasting agent from the container under the action of gravity, no negative pressure may occur in the container above the blasting medium. It is therefore necessary to provide ventilation openings on the container or lid so that ambient pressure prevails in the container at least above the blasting medium. Furthermore, according to the invention, no overpressure over the blasting medium is required, through which the blasting agent enters the blast pipe and continues to be transported to the workpiece to be blasted. This is a significant difference from the prior art which requires a compressor. The transport is carried out according to the invention solely due to the effect of the negative pressure in the environment of the object to be irradiated, ie at the outlet of the jet pipe, is sucked through the air through the jet pipe, which entrains the flowing from the container blasting agent.

On the container 8 (as shown) or on the housing 7 of the jet pipe unit further preferably a holding device (here in the form of a holding bracket 8D) is provided, on which the jet pipe unit can be suspended in position with standing upright container.

In order to be able to recognize the fill level in the container, this can be wholly or partially made of an at least partially transparent material or have a viewing window.

In an extension, not shown, can be provided at the connection region between the container 8 for receiving blasting agent and the jet pipe unit 5 to the jet pipe 6, for example, inclined by 45 ° pivoting plane in which the container 8 relative to the jet pipe 6 to a longitudinal axis of the jet pipe. 6 Angled axis is rotatable or pivotable. In this variant, the jet pipe 6 can be inclined relative to the horizontal, while the container 8 can still be arranged substantially vertically by pivoting in the inclined plane. Thus, the blasting agent can flow out of the container into the inlet, even with an inclined jet pipe substantially unhindered.

In an extension, not shown, an additional hose can be provided for the device, which can be connected at one end to the jet pipe unit at the inlet and at its other end has an adapter piece with an inlet, which with the then removed from the jet pipe unit container Can be coupled so that the outlet of the container at a certain distance is positioned over the inlet of the adapter piece and the blasting agent from the container can leak freely into the inlet of the adapter piece. The container may then be hung at a distance from the jet pipe to the headband and is connected to the jet pipe unit via the hose through which the blasting agent supply takes place. This extension is particularly useful when machining areas of workpieces that are inaccessible with the jet tube assembly and blasting media container positioned thereon, or when performing "overhead" work where the jet tube assembly can not be held vertically.

The evacuatable chamber 2 has a second, larger opening 1, which is approximately opposite the access opening 4 for the jet pipe 6 and with which the chamber can be placed on a workpiece to be machined. An elastic seal 1A for sealing the gap between the outer periphery of the opening 1 and the workpiece is attached to the chamber unit. By having the seal formed with a large elastic bead or rim, the chamber unit can still maintain a sealing contact with the workpiece surface, despite some flexibility, thus defining the processing area.

The chamber unit 2 has as in Fig. 1 and 2 11 show a further, third opening 3A for connecting a device for extracting air from the blasting chamber 2A in order to generate therein the negative pressure required for the operation of the device. The opening 3A may be in the form of a hose nozzle with or without additional connection means for fixing a hose, for example a plug connection or a locking connection such as a bayonet or latching connection. Particularly advantageous in the embodiment shown, in which the opening 3A is provided at the end of an outgoing of the blasting chamber 2A at an angle pipe socket 3, the possibility of the pipe socket as a handle for holding the then by hand easy to use chamber unit to use. In a particularly preferred embodiment of this pipe or connecting piece 3 is designed so that a commercially available vacuum cleaner, optionally using an intermediate piece and / or connecting hose can be connected.

The chamber unit 2 can be made of any material such as metal or plastic and in any form per se, as long as the entire construction withstands the expected negative pressure inside the blasting chamber 2A and the abrasive effect of the abrasive used as desired. However, the production as a one-piece up to the seals preferably one-piece Kunststoffspritzgießteil offers itself for cost reasons. Furthermore, the use of a transparent plastic is advantageous, because then an observation of the work area is ensured in use from all sides without having to remove the chamber unit from the processing site. Alternatively, one or more viewing windows could be provided for a non-or slightly transparent material.

The generation of the negative pressure in the blasting chamber 2A is possible when the processing opening 1 of the chamber unit 2 is placed on a surface by making the seal by means of the gasket 1A, the blast pipe 6 is inserted through the access opening 4, and the exhaust opening 6A on the blast pipe 6 for the blasting agent is located within the blasting chamber 2A and the suction works and sucks air from the interior of the blasting chamber 2A. However, the chamber does not have to be completely hermetically sealed. Decisive is such a seal that during operation inside the blasting chamber 2A still sufficient vacuum can be achieved by evacuation. In operation, ambient air is then drawn in through the air inlet opening 11 of the jet tube unit and transported through the jet tube 6 into the jet chamber 2A. Under the action of the negative pressure in the blasting chamber 2A, the blasting agent is also removed from the container Sucked 8 through the inlet 9 in the jet pipe unit and torn together with the air through the jet pipe into the interior of the jet chamber 2A and ejected there from the outlet opening 6A. In order to achieve a satisfactory suction of the blasting agent is leading to the inlet 9 pipe section of the connecting piece 12 is preferably mounted at an acute angle to the longitudinal or air flow direction.

By appropriate guidance of the jet pipe unit, the workpiece located in the chamber or the machining point defined and bounded by the machining opening 1 can be specifically processed. By changing the suction power, the radiant power can be varied easily. By the suction during the generation of the negative pressure, the spent blasting agent is sucked in at the same time so that a further additional suction as in conventional blasting systems, which work with excess pressure or compressed air as the transport medium for the blasting agent, omitted.

Claims (9)

1. A device for abrasive-blasting of workpieces, comprising
   a chamber unit (2) with a blasting chamber (2A) having a first opening (4), a second opening (1), and a third opening (3A), wherein said chamber unit (2) can be placed with said second opening (1) onto a workpiece that is to be treated, and said third opening (3A) allows to connect a device for the evacuation of air from the blasting chamber (2A);
   a blasting pipe unit (5) with a blasting pipe (6) which can be inserted through the first opening (4) into the blasting chamber (2A); and
   a container (8) for the accommodation of blasting material which is connected with said blasting pipe unit (5) in such a manner that said blasting material is moved out of the container (8) and through the blasting pipe (6) into the blasting chamber (2A) by means of the effect of the reduced pressure generated, in operation, in the blasting chamber (2A);
   characterized in that
   said container (8) for the accommodation of blasting material is mounted, or can be mounted, to the blasting pipe unit (5) in such a manner that said blasting material can freely flow out of the container (8) into an inlet (9) of the blasting pipe unit (5); and
   said blasting pipe unit (5) has an air inlet opening (11) for ambient air, and the blasting pipe (6) communicates with the air inlet opening (11) and with the inlet (9) for the blasting material
2. The device for abrasive-blasting of workpieces in accordance with claim 1, wherein the blasting pipe unit (5) comprises a receptacle (8B), which removably affixes the container (8) to the blasting pipe unit (5) in such a manner that an outlet (13) of the container (8) for the blasting material is located at a pre-specified distance above the inlet (9).
3. The device for abrasive-blasting of workpieces in accordance with claim 2, wherein the blasting material container (8) comprises a metering unit (10) for adjusting the amount of blasting material that exits through the outlet (13).
4. The device for abrasive-blasting of workpieces in accordance with one of the preceding claims, wherein an elastic gasket (1A) is provided for sealing the intermediate space between the circumference of the second opening (1) and said workpiece.
5. The device for abrasive-blasting of workpieces in accordance with claim 4, wherein the second opening (1) is located approximately opposite the first opening (4) for the blasting pipe (6).
6. The device for abrasive-blasting of workpieces in accordance with one of the preceding claims, wherein the opening (3A) for the connection of the evacuation device is provided on a pipe-connecting piece (3) protruding from the chamber unit (2), said pipe-connecting piece also acting as a handle for the chamber unit (2).
7. The device for abrasive-blasting of workpieces in accordance with one of the preceding claims, wherein a gasket (4A) is provided on the first opening (4) for the blasting pipe (6) in order to create a seal with respect to the blasting pipe (6) when said blasting pipe is inserted into the first opening (4).
8. The device for abrasive-blasting of workpieces in accordance with one of the preceding claims, wherein the chamber unit (2) is at least partially made of a transparent plastic material.
9. The device for abrasive-blasting of workpieces in accordance with one of the preceding claims, wherein the container (8) for the accommodation of blasting material is mounted, or can be mounted, to the blasting pipe unit (5) in such a manner that said container can be rotated or pivoted on an inclined plane relative to the blasting pipe (6).

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