The present invention is related to a device for processing substantially flat workpieces, said device comprising a transport surface for transportation through the device of each of the workpieces, and a processing unit, comprising a processing element having an abrasive surface and which is moveable parallel to the transport surface in order come into contact with each of the workpieces to be processed, a driving shaft and a carrier connected thereto for supporting the processing element, the driving shaft being transversely positioned on the carrier.
Such a device is known from U.S. Pat. No. 4,704,823.
In this text, processing is taken to mean, among others, the deburring, grinding and sanding of substantially flat workpieces. Semi-finished products punched or laser-cut from plate material are deburred at the edges or polished on the surface with the aid of the device described above. The device of U.S. Pat. No. 4,704,823 hereto comprises a processing disc which rotates in the horizontal plane under which a workpiece is transported. A drawback of said known device is that the workpiece is processed only on the side which is located parallel to the processing disc.
Further, from U.S. Pat. No. 5,105,583 a similar device for processing flat workpieces is also known. The processing disc of the device is provided with brush hairs transversely positioned thereon. It is possible to tilt the driving shaft, so that the processing disc will be inclined at a smaller angle with respect to the transport surface. In this event, the brush hairs also stand at an angle that is less than 90° with respect to the transport surface. The effect is an non-uniform pressing force. The drawback with this arrangement is that one disc does not allow a workpiece to be processed uniformly.
From EP 0 924 031, a brush disc with brush hairs is known in which the brush hairs are directed tangentially in the same direction of rotation as the disc, at an angle which is less than 90° with respect to the disc. Experimentally it was found that the brush hairs quickly have the tendency to bend permanently, thus shortening the life cycle of the brush.
The object of the present invention is to provide an improved device which is capable of multi-sided processing of substantially flat workpieces, including the removal of the oxide layer on the edge of the plate material as a result of laser cutting.
The device according to the invention is characterised in that the processing element comprises support members for supporting the abrasive surface, said support members being positioned at an angle of less than 90° with respect to the processing element. By providing the abrasive surface at an inclination with respect to the processing element, it is assured that the workpiece is not only processed on the edges and on either the upper or lower side, but also on the sides, that is, the surfaces at right angles to the upper and lower side.
According to the invention, the support members are at least radially directed with respect to the driving shaft of the carrier. Experimentally it has been found that when the support members are not tangentially directed, that is to say in the direction of rotation, the abrasive surface has a much longer life cycle. In comparison with the tangentially directed brush hairs, as is the case in EP 0 924 031, a processing element provided with radially, or at least partly radially directed support members is much less susceptible to wear.
The greatest effect is achieved if the support members are substantially radially directed with respect to the driving shaft.
The support members are preferably substantially inclined towards and/or away from the driving shaft in order to reinforce the processing effect.
In a preferred embodiment, the processing element comprises brush hairs as support members. Experimentally it has been found that brush hairs which are not at right angles with respect to the processing element have a high impact on the side of the workpiece, with a sufficient processing result as a consequence.
In this regard, the brush hairs may be impregnated with abrasive particles or themselves be made of steel, preferably stainless-steel, in order to obtain an abrasive surface.
The surface of the processing element with support members not positioned at right angles can be combined with already known processing surfaces, such as a web of nonwoven synthetic fibres provided with sanding grains, which material is sold under the name Scotch-Brite, or brush hairs, impregnated met abrasive particles, positioned at right angles with respect to the transport surface. With such a processing element, a further processing of the edges and either the upper or lower surface of the workpieces can be achieved.
In a further embodiment of the invention, the processing element further comprises brush hairs, placed between the support members at right angles to the processing element, which are preferably made of nylon. Said nylon hairs are provided to press the workpiece against the transport surface in order to prevent it from shooting away.
If the processing element is formed by at least one flat round disc, while the carrier is capable of being rotationally driven, the multi-sided processing of a workpiece, such as described in U.S. Pat. No. 4,704,823, is assured.
The diameter of the disc is preferably greater than the width of the transport surface, so that each workpiece will be processed by the abrasive surface of the processing element in at least two directions, regardless of the position of the workpiece on the transport surface.
The processing element is preferably removably connected to the carrier in order to allow the disc to be replaced in the event of wear of the abrasive surface.
Finally, the invention is also related to a processing element for application in a device for processing substantially flat workpieces according to the invention.