Improved machine tool

Abstract

Machine tool for machining workpieces, including: a linear guide (102) aligned in a predetermined direction (A'), wherein at least one upper surface section is defined in this linear guide (102); a sliding device (104) adapted to slide on the linear guide (102); wherein the sliding device (104) includes: at least one system with rolling elements (6) designed to enable the sliding device (104) to slide on the linear guide (102); a closure element (105'') extending along a direction substantially parallel to said predetermined direction (A') and arranged to prevent, in use, dust and machining residues from entering the at least one system of rolling elements (6); and a wiping element (107) extending along a direction substantially parallel to said predetermined direction (A'), wherein at least one wiping surface is defined in the wiping element (107) and is arranged to wipe over the at least one upper surface portion of the linear guide (102) while the sliding device (104) slides on the linear guide (102) in order, in use, to remove dust and / or machining residues from the at least one upper surface portion of the linear guide (102), characterized in that at least one bore (111) is formed on the at least one end portion of the stripping element (107), which bore faces the linear guide (102) and, in use, can be connected to a compressed air system in order to remove, in use, by means of compressed air discharge from the at least one bore (111), residual materials which arise during the machining of the workpieces which are located on the linear guide (102) downstream and / or upstream of the sliding device (104).

Description

The present invention relates to an improved machine tool.In particular, the invention relates to a machine tool which is also suitable for machining workpieces made of hard materials, such as, for example, aluminum, composite materials or else plastic materials.There are various types of machine tools which, in order to enable the relative movement between the workpiece to be machined and the tool, are equipped with one or more guides on which one or more slide shoes can slide.Normally, the guides are made in one piece with the base frame of the machine tool, while the sliding shoes are connected, if necessary by means of additional elements, to the machining tools or the workpieces to be machined.These machine tools, which provide for the removal of material from the workpieces, are usually also equipped with protective elements or elements, such as seals, in order to prevent the dust produced by the machining of the workpieces from being able to enter the intermediate spaces present between the slide shoe and the corresponding guide.In fact, the penetration of dust grains of greater or lesser size into the space between the shoe and the guide could lead to damage or even breakage of these two mechanical members, and consequently to the blocking of the shoe.In particular, in cases where the coupling between the shoe and the guide is of the recirculating ball or roller type, the possible presence of dust between the shoe and the guide could result in the blocking of the balls or rollers (depending on the type) and the breakage of the retaining members which hold the balls or rollers closely against the shoe.However, the protective members and elements listed above and normally used on machines of the known type do not fully fulfil the function for which they are intended, and thereby cause malfunctions or even breakage on the machines on which they are mounted.EP 1 676 040 B1 describes a guide carriage of a linear rolling bearing.DE 10 2008 053 932 A1 describes a linear rolling bearing having a guide carriage which is mounted on a guide rail such that it can be displaced longitudinally via rolling bodies and partially engages with its legs around the guide railWO 2016 / 152 123 A1 describes a linear guide device with improved dust tightness. To achieve this, this linear motion guide device has a guide rail, a runner, and a roller member. A sealing member is provided for sealing the gap formed between a side surface part of the guide rail and an inner surface part of the sliderU.S. Pat. No. 6,170,986 B1 describes a roller guide device for linear movements.DE 88 39 85 B describes a protective device, in particular for guideways of slide-like movable parts of wood-working machines.*In view of this, it is therefore the object of this invention to provide a machine tool equipped with a sliding device which prevents the occurrence of malfunctions or breakage on the machine caused by the accumulation of dust and machining debris in the area affected by the sliding movement of the device.Another object of the invention is to provide a machine tool that is reliable in use.A specific object of the present invention is therefore a machine tool for machining workpieces, comprising: a linear guide oriented in a predetermined direction, in which linear guide at least an upper surface portion is defined; a sliding device configured to slide on the linear guide; wherein the sliding device comprises: at least one system of rolling elements configured to allow the sliding device to slide on the linear guide; a closure element extending along a substantially parallel direction to said predetermined direction and arranged to prevent, in use, dust and machining debris from entering the at least one system of rolling elements; and a scraping member extending along a substantially parallel direction to said predetermined direction, wherein the scraping member defines at least one scraping surface arranged to brush over the at least one upper surface portion of the linear guide while the sliding device slides on the linear guide to remove, in use, dust and / or machining debris from the at least one upper surface portion of the linear guide.According to the invention, the at least one upper surface section of the linear guide and the at least one wiping surface of the wiping element are preferably substantially planar.Furthermore, according to the invention, the wiping element can extend over the entire length of the sliding device.Likewise according to the invention, the closure element can be provided between the scraping element and the at least one system with rolling elements.Further, according to the invention, the sliding device may include a bearing member including at least one system of rolling elements, and the scraping member may be detachably connected to the bearing member. According to the invention, the wiping element preferably consists of brass, bronze, rubber, polyurethane or plastic.Advantageously, the wiping element can, according to the invention, comprise a material strip in which the at least one contact surface is formed; this material strip being made of rubber, polyurethane, felt, plastic, brass or bronze, for example.Furthermore, according to the invention, at least one bore is formed on at least one end section of the stripping element, said bore facing the linear guide and being connectable, in use, to a compressed air system in order, in use, to remove residual materials from the at least one bore by means of the output of compressed air, said residual materials being produced during the machining of the workpieces which are located on the linear guide downstream and / or upstream of the sliding device.Also according to the invention, the at least one bore may include a plurality of bores made in a portion of the scraping element that is substantially "C"-shaped.Advantageously, the at least one bore can be inclined along a direction according to the invention such that the compressed air emerging from the at least one bore, in use, impinges on the linear guide in such a way that the residual materials which are produced during the machining of the workpieces are removed.In the following, this invention is described by way of illustration, but not limitation, in its preferred embodiments with particular reference to the figures of the accompanying drawings. The following are shown: FIG. 1 is a partial perspective view, viewed from a first point of view, of a group of a machine tool according to a first example, which is not part of the present invention; FIG. 2 is another partial perspective view, viewed from a second point of view, of the group shown in FIG. 1; FIG. 3 is a front view of the group of FIGS. 1 and 2 ; FIG. 4 is a partially cut front view of the assembly shown in FIGS. 1 to 3; FIG. 5 is a first perspective view of a component of the group of FIGS. 1 to 4; FIG. 6 is a second perspective view of the component shown in FIG. 5 ; FIG. 7 is a first partial perspective view of a group of a machine tool according to an embodiment of the present invention; FIG. 8 is a second partial perspective view of the assembly shown in FIG. 7; FIG. 9 is a front view of the group of FIGS. 7 and 8 ; and FIG. 10 is a perspective view of a component of the assembly shown in FIGS. 7-9.In the various figures, similar parts are identified by the same reference numerals.With particular reference to Figures 1 to 6, reference numeral 1 denotes a group of a machine tool in which a translatory movement of the workpiece or tool to be machined relative to the fixed parts of the machine is provided.Said group 1 includes a guide 2, for example a rectilinear prism guide.In detail, the guide 2 has an extension in a predetermined rectilinear direction A, and a prismatic cross section in which an upper longitudinal groove 2 aand a lower longitudinal groove 2 bare formed, which extend substantially along the entire longitudinal extension of the guide 2.In particular, the upper longitudinal groove 2 aand the lower longitudinal groove 2 bhave both a trapezoidal profile and are symmetrical to one another relative to a horizontal central plane of the guide 2.Although in the attached figures a guide 2 having a particular shape is shown, the present invention should not be considered in any way limited to this shape, since it can advantageously also function with guides having a shape other than the one shown in the figures.An end portion 2' of the guide 2 which does not have any of the longitudinal grooves 2a, 2b is rigidly and cantilevered from a fixed part 3 of the machine tool, such as a portion of the corresponding base, so that it protrudes laterally from the fixed part 3.The group 1 further provides a slide shoe 4 capable of sliding along the guide 2.The shoe 4 in turn comprises a bearing member 5 intended for direct coupling with the guide 2 and having a substantially "C"-shaped profile.For receiving the guide 2, a longitudinally directed recess 5' is defined in the bearing member 5, which recess points outwards and has a cross section whose shape is complementary to a portion of the guide 2 on which the upper 2a and lower 2b longitudinal grooves are located.In order to allow the relative movement of the guide 2 and the corresponding complementary portions of the shoe 4 in the two contact areas between the upper 2a and lower 2b longitudinal grooves, an upper ball or roller circulation system 6 and a lower ball or roller circulation system (not shown) are provided respectively.In the upper part of the support member 5, there are also formed a first threaded hole 5a and a second threaded hole (not shown) which are parallel to each other and the function of which will be described in more detail in the following description.Although not explicitly shown in the figures, the bearing member 5 can optionally also be connected to the workpiece to be machined or, alternatively, to the tool selected for the machining to be carried out on the workpiece with the aid of further mechanical elements and / or members. The assembly 1 also comprises a lateral plate 7 rigidly fixed to the bearing member 5 and arranged so as to bear closely against a flat surface 8 of the latter facing the fixed part 3 of the machine tool.At the lower part and over the entire length of the lateral plate 7 an additional strip 9 of relatively soft material can optionally be provided, such as rubber, polyurethane, felt, plastic, brass or bronze.More specifically, the lateral plate 7 is arranged directly above the end portion 2' of the guide 2 so that the additional strip 9 abuts against and strikes over a flat surface of the end portion 2' when the shoe 4 is in motion, thus obstructing at all times the lateral access path from outside to the upper ball or roller circulation system 6 and thus preventing the dust produced during the operations from entering there and entering the upper ball or roller circulation system 6 and impairing its function.According to further variants of the present invention, not shown in the attached figures, the additional strip 9 can be eliminated and instead a lateral plate made of a relatively soft material, such as bronze, brass, rubber, polyurethane or plastic, and arranged in direct contact with the underlying end portion 2' of the guide 2.On the upper part of the lateral plate 7, on the other hand, a first through hole 10 aand a second through hole 10 bare provided which are parallel to each other and each have a first widened portion 11 aand a second widened portion 11 bon an outer side 12 of the lateral plate 7 opposite to the side thereof which is in contact with the support member 5.The group 1 also includes a first bolt 13 aand a second bolt 13 bwhich are respectively passed through the first through hole 10 aand the second through hole 10 bof the side plate 7 so that the respective heads are accommodated in the first widened portion 11 aand the second widened portion 11 b.The first screw 13a and the second screw 13b are also screwed into the first threaded hole 5a and into the second threaded hole of the bearing member 5 in order to achieve the rigid coupling between the latter and the lateral plate 7.On the bearing member 5 there is further mounted a linear seal 5" which is arranged parallel to the direction A in a region between the upper ball or roller circulation system 6 and the contact region between the lateral plate 7 and the guide 2 beneath it, in order to form a further protection barrier against the penetration of the machining residues from outside into the upper ball or roller circulation system 6.Furthermore, the lateral plate 7 itself, being a solid component, acts not only as a guide cleaner but also as a closure element to prevent dust and / or machining residue from entering the upper ball or roller circulation system 6 from the outside.Further, although not shown in the figures, in the group 1, a front shutter and / or cleaning system and a rear shutter and / or cleaning system may be provided respectively at the front portion and the rear portion of the shoe 4, i.e., downstream and upstream of the upper ball or roller circulating system 6, for preventing dust and machining debris from entering the upper ball or roller circulating system 6 from said front and rear portions.On the other hand, referring to FIGS. 7-10, reference numeral 100 denotes another group of a machine tool according to another embodiment of the present invention.The group 100 comprises a rectilinear guide 102 oriented in a predetermined rectilinear direction A' and rigidly connected in a cantilevered manner to a fixed part 103 of the machine tool.This guide 102 has the same shape as that of the guide 2 described above.The assembly 100 includes a slide shoe 104 equipped with a bearing member 105 in which a recess 106 is made, which is open to the outside of the bearing member 105 and has a shape complementary to a portion of the guide 102, so that the slide shoe 104 is constrained to slide on the guide 102.Also in this case, between the upper and lower grooves of the guide 102 and the corresponding complementary portions of the bearing member 105, an upper ball or roller circulation system and a lower ball or roller circulation system (not shown) are respectively provided to allow the sliding of the sliding shoe 104 along the guide 102.The assembly 100 also comprises a profiled member 107 which can be rigidly and detachably connected to the support member 105.Formed integrally in the profiled member 107 are a lateral element 108 of substantially "C"-shaped profile and an elongated plate 109 extending from an upper portion of the lateral element 108.At the lower part and over the entire length of the elongated plate 109 an additional strip 110 of relatively soft material is provided, such as rubber, polyurethane, felt, plastic, brass or bronze.Alternatively, as in the previously described embodiment, the additional strip 110 may be excluded and instead the elongate plate 109, or the entire profiled member 107, may be made of a relatively soft material, such as bronze, brass, rubber, polyurethane or plastic.More specifically, the elongated plate 109 and the corresponding additional strip 110 are arranged so that the latter abuts against an upper surface of the guide 102 and slides on the guide 102 when the slide shoe 104 is set in motion.The function of the elongated plate 109, in cooperation with the additional strip 110, if present, to prevent dust and machining debris from being able to enter laterally into the upper contact area between the shoe 104 and the guide 102.The lateral element 108, on the other hand, has a plurality of holes 111 provided in a "C"-shaped area of the corresponding front side and facing the guide 102.The plurality of holes 111 can be connected to a compressed air system (not shown) which serves to emit a stream of compressed air directed onto the guide 102 and thus to enable the removal of dust or machining residue which may have previously accumulated in the region of the guide 102 in the vicinity of the sliding shoe 104.In particular, each bore of the plurality of bores 111 is oriented such that the discharged compressed air flow is oriented such that any residues or dust present are removed from the sliding region of the sliding shoe 104.In this case, too, a linear seal 105" is provided on the support member 105, which seal is arranged parallel to the direction A' in an edge region of the recess 106 and is designed to come into contact with the guide 102 lying beneath it, in order thus to close the passage between the latter and the support member 105.According to a variant of the shoe 104, not shown in the figures, a further lateral element such as that described above can be provided in the profiled member 107.This further lateral element is fixed to the elongated plate 109 on the side opposite to the above mentioned lateral element 108, and is also connected to the compressed air system.This particular variant of the shoe 104 makes it possible to remove any dust or residue that may have accumulated on the guide 102 upstream or downstream of the shoe 104.As can be seen from the above description, the machine tool according to the invention has a structure designed to be able to effectively prevent dust and debris from being able to enter the areas of interaction between the shoe and the corresponding guide, so as to avoid jamming of the shoe caused by these machining debris or even breakage of the shoe or guide.The advantages obtained with the machine tool proposed here are even more clearly apparent in the cases where said machine is used for the machining of workpieces of a certain hardness, since in these situations the dust produced by the machining has a very small grain size and can thus even more easily penetrate into very small spaces.This invention has been described illustratively, but not by way of limitation, in the preferred embodiments. However, variations and / or modifications may be made by those skilled in the art, all of which fall within the scope as defined in the appended claims.

Claims

A machine tool for machining workpieces, comprising: a linear guide (102) oriented in a predetermined direction (A'), wherein at least a top surface portion is defined in said linear guide (102); a sliding device (104) configured to slide on said linear guide (102); wherein said sliding device (104) comprises: at least one system of rolling elements (6) configured to allow sliding of said sliding device (104) on said linear guide (102); a closure element (105") extending along a substantially parallel direction to said predetermined direction (A') and arranged to prevent, in use, dust and machining debris from entering said at least one system of rolling elements (6); and a scraping element (107), which extends along a substantially parallel direction to said predetermined direction (A'), wherein in the scraping element (107) at least one scraping surface is defined, which is arranged to scrape over the at least one upper surface portion of the linear guide (102) while the sliding device (104) slides on the linear guide (102) in order, in use, to remove dust and / or machining residues from the at least one upper surface portion of the linear guide (102), characterized in that at the at least one end portion of the scraping element (107) at least one bore (111) is formed, which faces the linear guide (102) and, in use, can be connected to a compressed air system in order, by means of output of compressed air from the at least one bore (111), to remove residual materials which arise during the machining of the workpieces, which are located on the linear guide (102) downstream and / or upstream of the sliding device (104).Machine tool according to claim 1, characterised in that the at least one upper surface section of the linear guide (102) and the at least one scraping surface of the scraping element (107) are substantially planar.Machine tool according to one of the preceding claims, characterized in that the wiping element (107) extends over the entire length of the sliding device (104).Machine tool according to one of the preceding claims, characterized in that the closure element (105") is provided between the scraping element (107) and the at least one system with rolling elements (6).Machine tool according to any of the preceding claims, characterized in that the sliding device (104) comprises a bearing element (105) comprising the at least one system of rolling elements (6), and in that the scraping element (107) is detachably connected to the bearing element (105).Machine tool according to one of the preceding claims, characterized in that the wiping element (107) consists of brass, bronze, rubber, polyurethane or plastic.Machine tool according to one of the preceding claims, characterized in that the wiping element (107) contains a material strip (110) in which the at least one contact surface is formed; this material strip (110) consisting, for example, of rubber, polyurethane, felt, plastic, brass or bronze.Machine tool according to any one of claims 1 to 7, characterized in that said at least one bore comprises a plurality of bores (111) made in a portion of said scraping element (107) which is substantially "C"-shaped.Machine tool according to one of Claims 1 to 8, characterized in that the at least one bore (111) is inclined along a direction such that the compressed air emerging from the at least one bore (111), in use, impinges on the linear guide (102) in such a way that the residual materials which are produced during the machining of the workpieces are removed.

Images