Tool arrangement with a protective hood featuring a locally reflection-reduced section

Abstract

Tool arrangement (1) comprising: a tool (3) for machining a workpiece (5), a laser marking device (9) for producing a visually perceptible marking (27) on a surface (6) of the workpiece (5) by illuminating it with a directed laser beam (23), a protective hood (17) for at least partially covering parts of the tool (3) and / or an area between the surface (6) of the workpiece (5) and the tool (3), while the protective hood (17) is arranged in a protective position, wherein the protective hood (17) is made of optically transparent material, characterized by the fact that a surface (16) of the protective hood (17) in a reflection-reduced sub-area (29) where the directed laser beam (23) hits the protective hood (17) when the protective hood (17) is arranged in the protective position, is modified such that the incident laser beam (23) is reflected back with a lower directed reflection than in an adjacent non-reflection-reduced sub-area (30) of the protective hood (17).

Description

Field of invention

[0001] The present invention relates to a tool arrangement comprising a tool for machining a workpiece, in particular a pillar drill. State of the art

[0002] Tools are generally used to machine workpieces. For example, holes can be drilled, recesses countersunk, grooves milled, the workpiece cut, sawn, machined, or similar operations performed locally. For this purpose, a part of the tool that performs the machining is generally brought into local contact with a surface of the workpiece to be machined. For example, in the case of a tool designed as a pillar drill (sometimes also called a pillar drill), a drill bit held in a drill head is rotated and brought to the surface of the workpiece at the position where a hole is to be drilled.

[0003] To precisely align the tool and workpiece relative to each other, and thus enable machining of the workpiece at a specific desired location, laser marking devices have been developed. These devices create a visually perceptible mark on the workpiece surface by illuminating it with a directed laser beam. This mark can indicate the position where the tool will come into contact with and machine the workpiece surface during normal use. For example, with a pillar drill, a mark in the form of a cross or similar can be projected onto the workpiece surface with the directed laser beam at the point where the drill bit will encounter the workpiece surface as it moves towards the workpiece.

[0004] Adjacent to parts of the tool and / or in the area between the workpiece surface and the tool, a protective hood can often be provided. This hood can, for example, prevent the user from coming into contact with hazardous parts of the tool, such as a rotating drill head. Additionally or alternatively, the hood can also act as a splash guard or chip guard. If necessary, the hood can be positioned between a protective position and an open position, in which it is, for example, folded away to allow access to the workpiece area being machined. To allow the user to observe the workpiece during machining, particularly in the area being machined, such a hood is usually made of an optically transparent material.

[0005] Such tool arrangements are known from the publications DE 103 34 048 A1 and DE 20 2004 013 801 U1. Disclosure of the invention Advantages of the invention

[0006] Embodiments of the present invention can advantageously provide a tool arrangement by means of which a workpiece can be machined in a simpler, and in particular more intuitive, manner than with conventional similar tool arrangements. In particular, the tool arrangement can be adapted so that a position to be machined on a surface of the workpiece can be marked precisely and unambiguously by means of a laser marking device.

[0007] According to one aspect of the invention, a tool arrangement is proposed comprising a tool for machining a workpiece, a laser marking device for generating a visually perceptible mark on a surface of the workpiece by illuminating it with a directed laser beam, and a protective hood for at least partially covering parts of the tool and / or an area between the surface of the workpiece and the tool while the protective hood is arranged in a protective position. The protective hood is made of optically transparent material.The tool arrangement is characterized by the fact that a surface of the protective hood in a so-called reflection-reduced sub-area, in which the directed laser beam hits the protective hood when the protective hood is arranged in the protective position, is modified in such a way that the incident laser beam is reflected back with a lower directed reflection than in an adjacent non-reflection-reduced sub-area of ​​the protective hood.

[0008] Ideas for embodiments of the present invention can be considered, among other things and without limiting the invention, as being based on the thoughts and findings described below.

[0009] As mentioned in the introduction, conventional tool arrangements, such as a tool arrangement with a pillar drill, often include a laser marking device and a protective hood made of transparent material in addition to the tool itself. Both the laser marking device and the protective hood can be positioned close to the tool. For example, the laser marking device can be integrated into a common housing with the tool or attached at a fixed position relative to the tool. The protective hood can also be attached at a desired position relative to the tool.It may be provided that the protective hood can be moved between a protective position and a position that does not provide such protection, i.e., that the protective hood can be moved, in particular pivoted or shifted, between a position in which it protects a rotating part from access and a position in which it cannot provide such protection.

[0010] It has now been recognized that certain configurations of the laser marking device on the one hand and the protective hood on the other, or their relative positioning to each other, can impair the function of the laser marking device of visually marking the surface of the workpiece by illuminating it with the directed laser beam. In particular, situations were observed in which, when the protective hood was in its protective position, the visually perceptible marking produced by the laser marking device was disrupted. For example, near a cross projected by the directed laser beam as a marking, interfering lines, dots, or color patterns were observed, which can make it difficult to clearly recognize the visually perceptible marking in the application.

[0011] Further investigations revealed that these marking disturbances could be attributed to the protective housing. Specifically, it was suspected that the interfering patterns might be caused by local reflections of portions of the directed laser beam off certain areas of the protective housing. Such directed reflections could arise, among other reasons, because the protective housing, in order to achieve the best possible optical transparency, should have a smooth surface, and directed reflections are more likely to occur off such smooth surfaces. Total internal reflection of light entering the protective housing at a rear surface of the housing can also occur.

[0012] It is therefore proposed to examine a tool arrangement designed to be protected against such interference to determine where the directed laser beam of the laser marking device strikes the protective hood when the hood is in its protective position. Based on this knowledge, corresponding sections of the protective hood's surface should then be designed as reflection-reduced areas. In these areas, the surface of the protective hood is modified so that the incident laser beam is reflected back with a lower directional reflection than in adjacent sections of the protective hood that have not been modified to reduce reflection. This would allow, for example, continued unimpeded observation of the workpiece through the protective hood.

[0013] In other words, it was recognized as advantageous to treat and modify the surface of the protective hood in the so-called reflection-reduced area in such a way that the incident laser beam is either reflected back less strongly overall than in neighboring areas, or at least that instead of a directed, beam-like reflection in the reflection-reduced area, at most a diffuse and therefore non-beam-like reflection occurs.

[0014] Due to such an overall reduced reflection, or at least only diffusely permitted reflection, it can be avoided that locally reflected parts of the directed laser beam at the protective hood interfere with the marking to be effected on the surface of the workpiece.

[0015] The reflection-reducing property in the section of the protective hood to be modified can be achieved in various ways. For example, the reflection-reduced section can be specifically modified so that the incident laser beam is reflected, but this reflection is diffuse rather than directional. Alternatively or additionally, the reflection-reduced section can be modified so that the incident laser beam is at least partially absorbed, resulting in a lower reflected portion of the laser beam in this modified section compared to adjacent, non-reflection-reduced sections of the protective hood.From the reflection-reduced area, only less directed reflected light from the laser beam can be directed towards the vicinity of the marking to be produced, and if any such reflected light is directed from there towards the surface of the workpiece, it is predominantly reflected back as a kind of diffuse background light and not in the form of disturbing light patterns.

[0016] According to one embodiment, the protective hood can have a surface roughness in the reflection-reduced area that is higher than in the non-reflection-reduced area. In other words, the protective hood can be selectively roughened locally in the reflection-reduced area. This allows the protective hood to be designed to be more diffusely reflective locally, i.e., almost milky or matte, than in adjacent non-reflection-reduced areas, where the protective hood is generally intended to be as transparent as possible, i.e., optically translucent, to allow, for example, observation of the workpiece surface through the protective hood. Such local roughening can be achieved technically in various ways and is easy to implement.

[0017] In such an embodiment, the surface roughness in the reflection-reduced area can be designed such that the incident laser beam is predominantly diffusely reflected and / or predominantly diffusely transmitted. In other words, the surface roughness can be locally induced such that, due to this roughness, the incident laser beam is predominantly no longer reflected in a directed manner, but rather scattered or diffusely reflected by the rough surface, and thus no longer reaches the vicinity of the marking on the workpiece surface as a directed light pattern, but at most as an undirected background of light.

[0018] A portion of the incident laser beam can also be diffusely transmitted through the roughened surface. If this occurs when the laser beam enters the material of the protective cover, this transmitted portion may be reflected again from an opposite surface of the cover. However, since the transmission is intended to be diffuse, this reflected light will not be directed, but will only diffusely travel towards the vicinity of the marking on the workpiece surface and therefore generally will not cause any interference.

[0019] In this context, "predominantly diffusely" reflected or transmitted can be understood to mean that a predominant proportion, i.e. more than 50%, preferably more than 70%, 80% or 90%, of the light from the incident laser beam is not directed, but diffusely reflected or transmitted in various directions and with a substantially homogeneous directional intensity distribution.

[0020] The roughness to be created on the surface in the reflection-reduced sub-area can be generated in various ways.

[0021] According to one embodiment, the protective hood can, for example, be designed as a one-piece injection-molded part, produced using an injection mold that has a rougher surface in the reflection-reduced area than in the non-reflection-reduced area. In other words, even during the manufacturing process of the protective hood as an injection-molded part, it can be ensured that the protective hood has areas with varying degrees of reflection, and specifically that the injection-molded part has a rougher surface in the area where the directed laser beam is expected to strike during normal operation, compared to adjacent areas.For this purpose, an injection mold can be locally roughened, for example by locally corroding the surface of the injection mold, in particular by local etching, preferably anisotropic etching, in the area forming the reflection-reduced section. The protective hood can thus be very easily formed in one piece and provided with the reflection-reduced section.

[0022] According to one embodiment, the protective hood can be provided with a direct reflection-reducing layer in the reflection-reduced area. In other words, a layer can be selectively applied locally to, for example, a transparent base body of the protective hood, which reduces direct reflection emanating from this area. Such a layer can be easily retrofitted to an existing protective hood. An existing tool assembly can thus be easily upgraded.

[0023] According to one embodiment, the layer can be designed such that the incident laser beam is predominantly diffusely reflected. For this purpose, the layer can, for example, have a rough surface of suitable roughness and thus reflect diffusely, albeit only in a "matte" manner. Alternatively or additionally, diffusely reflecting particles or a diffusely reflecting particle mixture can be integrated into the layer, giving it a "milky" appearance. Such a diffusely reflecting, additionally applied layer can provide similar advantages to those explained above with regard to a specifically roughened surface of the protective hood.

[0024] Alternatively, according to one embodiment, the layer can be designed such that the incident laser beam is predominantly absorbed. In other words, the locally applied layer can be formed with an absorbing material or with particles of an absorbing material incorporated into the layer, so that incident light from the laser beam is predominantly absorbed rather than reflected. Even in such a configuration, disruptive effects caused by light from the laser beam reflected by the protective cover can be efficiently avoided.

[0025] According to one embodiment, the layer to be applied locally to the protective cover can be a film, which is attached locally to a transparent base body of the protective cover in the reflection-reduced area. In other words, the reflection at the protective cover can be selectively reduced locally by applying, for example, a film that is specifically matte and / or milky-turbid. The film can, for example, be a self-adhesive film. Such a film can be provided cost-effectively, easily applied locally to the transparent base body of a protective cover, and / or thus a suitable local reflection property can be easily modified in an existing protective cover.

[0026] According to one embodiment, the reflection-reduced area is arranged on a surface of the protective hood that faces the tool. In other words, a protective hood typically has two opposing surfaces, one facing the tool and the other facing away from it. It is considered advantageous to modify the tool-facing surface of the protective hood in such a way as to form the reflection-reduced area. For example, this surface can be locally roughened or provided with a matte or absorbing layer. This ensures that the tool-facing surface, which the laser beam of the laser marking device typically strikes first, is already designed to exhibit reduced directional reflection.This has proven to be particularly efficient in avoiding unwanted reflection patterns.

[0027] Alternatively or additionally, the optical properties of the opposite surface of the protective hood, the one facing away from the tool, can also be modified to form the reflection-reduced area. The portions of the laser beam penetrating the transparent protective hood will then be predominantly reflected non-directionally, at least at the rear surface of the protective hood, as would otherwise be the case with total internal reflection at a smooth, for example polished, surface.

[0028] According to one embodiment, the tool arrangement is configured so that the directed laser beam can be shifted relative to the tool. In other words, the tool and / or the laser marking device can be designed such that the laser beam generated by the marking device can be shifted relative to the tool. This can be achieved, for example, by shifting the laser marking device itself relative to the tool, or by incorporating suitable measures within the laser marking device to shift or deflect the laser beam it generates. By shifting the laser beam relative to the tool, the visually perceptible marking on the surface of the workpiece can be appropriately repositioned, for example, to mark a position where the tool is to make contact with the workpiece.

[0029] It is noted that some of the possible features and advantages of the invention are described herein with reference to different embodiments of a tool arrangement and the protective hood to be used therein. A person skilled in the art will recognize that the features can be suitably combined, adapted, or exchanged to arrive at further embodiments of the invention. Brief description of the drawings

[0030] The following describes embodiments of the invention with reference to the accompanying drawing, whereby neither the drawing nor the description is to be interpreted as limiting the invention. Fig. Figure 1 shows a tool arrangement according to an embodiment of the present invention.

[0031] The figure is merely schematic and not to scale. Embodiments of the invention

[0032] Fig. Figure 1 shows a tool arrangement 1 according to an embodiment of the present invention. The tool arrangement 1 comprises a tool 3 for machining a workpiece 5. In the illustrated example, the tool is a pillar drill 7, in which a drilling machine 9, or at least its drill head 11, together with a drill bit 13 attached thereto, can be displaced, for example, vertically in a displacement direction 15 in order to drill holes in the workpiece 5.

[0033] An area adjacent to the drilling machine 9, or between the drilling machine 9 and the workpiece 5, that is, in particular an area in the horizontal direction adjacent to the rotating drill 13 and the rotating drill head 11, can be protected by means of an optically transparent protective hood 17. The protective hood 17 is intended, on the one hand, to prevent a user from coming into contact with hazardous components of the tool assembly 1 or its tool 3. On the other hand, the protective hood 17 is to be made of optically transparent material so that the user can still observe the workpiece 5 at the positions to be machined, as well as components of the tool protected behind the protective hood 17.

[0034] The tool arrangement 1 further comprises a laser marking device 19. The laser marking device 19 has a laser light source for emitting a laser beam 23, preferably with low power, e.g., in the milliwatt range, and is further equipped by suitable means such as lenses, mirrors, apertures, etc., to align and shape the laser beam 23 in a desired manner. In the illustrated example, the laser marking device 19 is integrated into a housing of the drilling machine 9 and has, for example, an optic 21 on its surface facing the workpiece 5, through which a laser beam 23 of the desired shape or geometry can be directed toward a surface 6 of the workpiece 5. The laser beam 23 can thereby generate a desired pattern 25, for example, in the form of a cross, which can serve as a visually perceptible marking 27.The marking 27 can, for example, mark a position on the surface 6 where the drill 13 will come into contact with the workpiece 5 when moving downwards and can drill a hole there.

[0035] Due to the design of the laser marking device 19 on the one hand and the protective hood 17 on the other, as well as the relative positioning of these two components to each other, it is possible that parts of the laser beam 23 emitted by the laser marking device 19 may strike parts of the protective hood 17, which is arranged in a protective position. Once it has been determined where such an impact of parts of the laser beam 23 is to be expected, a suitable reflection-reduced section 29 can be created on the protective hood 17 at those points, in which incident light is reflected less directionally than in an adjacent non-reflection-reduced section 30.

[0036] As in the Fig. In the view shown in dashed lines, enlarged and rotated by 90°, the reflection-reduced section 29 can be generated, for example, by creating a locally increased roughness 31 on a surface 16 of the protective hood 17 facing the drill head 11. The roughness 31 can be created such that the incident portions of the laser beam 23 are predominantly not reflected directionally but at most diffusely.

[0037] The reflection-reduced section 29 can, for example, be made suitably rough during the manufacturing of the protective hood 17. For instance, to produce an injection-molded protective hood 17 from a transparent plastic such as polycarbonate, an injection mold can be used that is suitably rough in the areas intended to form the reflection-reduced sections 29, while surrounding areas of the injection mold are designed with a smooth surface to ensure the protective hood 17 remains transparent in those areas.

[0038] Alternatively, a protective hood 17 that is initially manufactured with a smooth surface over its entire area can subsequently be roughened in the reflection-reduced section 29, for example by local grinding, sandblasting, etc.

[0039] As a further alternative, a layer 33, for example in the form of an adhered film 35, can be applied locally to a transparent base body 18 of the protective hood 17. This film 35 can, for example, have a rough surface or a mixture of small particles integrated into a carrier material, thus appearing optically matte. Alternatively or additionally, the film 35 can be at least partially light-absorbing, for example by integrating light-absorbing particles or pigments into a carrier material of the film 35.

[0040] Finally, it should be noted that terms such as "comprising," "encompassing," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Reference numerals in the claims are not to be considered as limitations.

Claims

[1] Tool arrangement (1) comprising: a tool (3) for machining a workpiece (5), a laser marking device (9) for producing a visually perceptible marking (27) on a surface (6) of the workpiece (5) by illuminating it with a directed laser beam (23), a protective hood (17) for at least partially covering parts of the tool (3) and / or an area between the surface (6) of the workpiece (5) and the tool (3), while the protective hood (17) is arranged in a protective position, wherein the protective hood (17) is made of optically transparent material, characterized by , that a surface (16) of the protective hood (17) in a reflection-reduced sub-area (29) where the directed laser beam (23) hits the protective hood (17) when the protective hood (17) is arranged in the protective position, is modified such that the incident laser beam (23) is reflected back with a lower directed reflection than in an adjacent non-reflection-reduced sub-area (30) of the protective hood (17). [2] Tool arrangement according to claim 1, wherein the protective hood (17) has a surface (16) with a roughness (31) in the reflection-reduced part (29) which is higher than in the non-reflection-reduced part (30). [3] Tool arrangement according to claim 2, wherein the roughness (31) of the surface (16) in the reflection-reduced partial area (29) is such that the incident laser beam (23) is predominantly diffusely reflected and / or diffusely transmitted. [4] Tool arrangement according to one of the preceding claims, wherein the protective hood (17) is formed as a one-piece injection molded part which is produced by means of an injection mold which has a rougher surface in a region forming the reflection-reduced part (29) than in a region forming the non-reflection-reduced part (30). [5] Tool arrangement according to one of the preceding claims, wherein the protective hood (17) is provided with a direct reflection reducing layer (33) in the reflection-reduced part area (29). [6] Tool arrangement according to claim 5, wherein the layer (33) is designed such that the incident laser beam (23) is predominantly diffusely reflected. [7] Tool arrangement according to claim 5, wherein the layer (33) is designed such that the incident laser beam (23) is predominantly absorbed. [8] Tool arrangement according to one of claims 5 to 7, wherein the layer (33) is formed as a film (35) which is attached locally in the reflection-reduced part area (29) to a transparent base body (18) of the protective hood (17). [9] Tool arrangement according to one of the preceding claims, wherein the reflection-reduced part (29) is arranged on a surface (16) of the protective hood (17) which is directed towards the tool (3). [10] Tool arrangement according to one of the preceding claims, wherein the tool (3) is a pillar drill (7). [11] Tool arrangement according to one of the preceding claims, wherein the directed laser beam (23) is displaceable relative to the tool (3).

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