Tool for circular cutting of rubber

Abstract

The invention relates to a tool for circularly cutting rubber, comprising at least one rod-shaped cutting element received in a blade holder, with a tool holder for connecting the tool to a drive configured to rotate the tool about a rotational axis. The tool according to the invention is characterized in that a radial adjustment is provided, which is configured to displace the blade holder radially relative to the rotational axis in order to set a predetermined distance between the cutting element, which is aligned parallel to the rotational axis, and the rotational axis. The invention also relates to a machine tool for use with such a tool.

Description

[0001] The invention relates to a tool for circular cutting of rubber according to the type defined in the preamble of claim 1. Furthermore, the invention relates to a machine tool for such a tool.

[0002] It is generally known from the prior art that rubber can be cut with knife-like tools. Cutting, in the sense of the present invention, refers to cutting rubber in such a way that the rubber material is "cut" by a cutting edge, so that although the rubber material splits and a cut remains, no rubber material is removed, as is the case, for example, with the also conceivable machining of rubber. Tools for non-cutting cutting generally have a knife-like mechanical cutting element which is accommodated in a cutting edge holder. With longer cutting lengths and especially with greater cutting depths, this leads to high friction between the rubber and the cutting element and thus to extremely high performance requirements.DE 10 2016 202 487 A1 therefore describes a tool with a cutting element that has means for supplying a liquid lubricant. This reduces the required machine power and improves cutting quality.

[0003] For example, when manufacturing cable and line penetrations from the outside to the inside of a building, it is common practice to use rubber sheets or discs for sealing. Since the exact size of the corresponding line element when inserted into the building is typically not known during the manufacture of these rubber discs, the rubber discs are pre-cut to the typical diameters of pipes and / or cables over a large part of their thickness. The cuts then typically form concentric, nested circular incisions, so that on site only the areas of the rubber disc that are not required are broken out. The diameter can therefore be adjusted on site by selecting the appropriate pre-cut annular structures of the rubber disc.

[0004] This is possible using the tools described in the aforementioned DE 10 2016 202 487 A1, and thanks to fluid lubrication, it can be achieved with good cutting quality even at moderate machine power. However, each cut requires a specific tool that matches its diameter. Accordingly, numerous tools, large tool magazines, and frequent tool changes are necessary. This adversely impacts the cost and time required to manufacture such rubber components.

[0005] The object of the present invention is to provide a tool for cutting rubber according to the preamble of claim 1, which is highly flexible and avoids the aforementioned disadvantages. Furthermore, the object of the invention is to provide a machine tool for operating such a tool.

[0006] According to the invention, this object is achieved by a tool having the features in the characterizing part of claim 1. Advantageous embodiments and further developments of the tool according to the invention emerge from the dependent subclaims. Furthermore, a machine tool having the features in claim 10 solves the problem. Here, too, advantageous embodiments and further developments emerge from the dependent subclaims.

[0007] The tool according to the invention for circularly cutting rubber provides at least one rod-shaped cutting element, which is accommodated in a blade holder. Furthermore, the tool comprises a tool holder for connecting the tool to a drive for rotating the tool about a rotational axis. This design is known from the aforementioned DE 10 2016 202 487 A1. According to the invention, a radial adjustment is provided, which is designed to displace the blade holder radially relative to the rotational axis in order to set a predetermined distance between the cutting element, which is aligned parallel to the rotational axis, and the rotational axis.

[0008] The inventive design of the tool with radial adjustment now allows a multitude of concentric cuts to be made around the tool's axis of rotation without having to change the tool. Rather, it is sufficient to lift the tool axially from the rubber element to be cut, radially displace the cutting element together with its cutter holder using the radial adjustment, and then immediately make the next cut. This means that a single tool is sufficient to make concentric circular cuts up to a maximum diameter limited only by the tool. Typically, a rubber plate or rubber disc, a so-called round blank, with all the cuts required for a house lead-in can be produced extremely quickly and efficiently using one and the same tool.

[0009] The radial adjustment comprises an adjustment mechanism acting in the radial direction, which allows the required adjustment simply and efficiently. This could be any linear drive. According to a particularly preferred embodiment, the radial adjustment can have at least one spindle aligned perpendicular to the axis of rotation, which engages with a toothing of the at least one cutter holder such that rotation of the spindle causes a radial movement of the cutter holder. The cutter holder can therefore have a toothing, a gear, a threaded nut, or the like, so that it moves radially along a spindle when the spindle is rotated.

[0010] According to a particularly advantageous embodiment, the spindle can be connected to a gear in a rotationally fixed manner, allowing the spindle's rotational movement to be realized simply and efficiently by rotating the gear. For this purpose, an actuator can engage the gear and rotate it together with the spindle. "Rotationally fixed" refers to a connection of the elements in such a way that, in the event of rotation of one element, they both rotate at the same angular velocity.

[0011] Particularly preferably, it can be provided that two radially aligned spindles with opposing threads are provided, which are both designed to be non-rotatable with the gear, which have the same geometric dimensions, and which have the cutter holder and the cutting element or a counterweight corresponding thereto. Preferably, a double spindle is therefore designed, in which a non-rotatable connection with the gear is ideally present in the region of the axis of rotation, i.e. between the two spindles. The spindles are provided with opposing threads, with at least one cutter holder with the cutting element being arranged on one spindle, and a comparable cutter holder with a cutting element or a counterweight corresponding thereto being arranged on the other spindle.This design, which is rotationally symmetrical to the axis of rotation, allows for even weight distribution in all radial positions of the cutting holder and the cutting element, so that no imbalances arise even during rapid rotation around the axis of rotation.

[0012] In principle, several cutting holders and cutting elements arranged on multiple spindles are conceivable. These are then preferably evenly distributed around the circumference to avoid imbalances, similar to the described design with two spindles.

[0013] In practice, however, it has been shown that the tool works particularly efficiently and delivers high-quality cuts when a single cutting element is used. As explained above, this single cutting element can then be used to cut the numerous concentric circles into the rubber element one after the other by adjusting the element radially accordingly.

[0014] A further very advantageous embodiment of the tool according to the invention can also provide that the at least one cutting element or the at least one cutting edge holder is designed to be angularly adjustable about an axis parallel to the axis of rotation. According to a very advantageous embodiment, this can be achieved via a lever element which the cutting edge holder has. The cutting edge holder can therefore be designed to be angularly adjustable. The cutting element will typically have a cutting edge which, in a basic position, is positioned tangentially to the orientation of the circle to be cut. An adjustment can be made here via the angular adjustment, for example to compensate for tolerances and / or to select a setting which deviates from the tangential setting.

[0015] According to a very advantageous development of the tool according to the invention, the cutting element can have at least one supply channel for a liquid lubricant to the part of the cutting element in cutting engagement. According to a very advantageous development, the lubricant can be supplied via the tool holder and the cutting edge holder, for example, via a hose line or the like leading from the tool holder to the cutting edge holder. This reduces the cutting power and improves the cutting quality through the liquid lubrication of the cutting element.

[0016] The machine tool according to the invention provides a chuck that accommodates the tool holder and a drive for rotating the tool about a rotational axis. Furthermore, an infeed device is provided for moving the tool along the rotational axis, so that the infeed movement is realized via the machine tool during the cut. The machine tool is characterized by an adjustment device that is configured to actuate the radial adjustment when the tool is in a home position.

[0017] The radial adjustment of the tool can, in principle, be carried out in any desired manner. For example, a stepper motor or other type of drive could be provided within the tool. Manual adjustment would also be conceivable. However, this would be correspondingly complex. Therefore, the machine tool according to the invention provides its own adjustment device. After an initial cut has been made, the tool is moved to a home position, for example, a position significantly above the rubber element to be produced, in particular a position at an upper end point of the feed movement. In this position, the adjustment device can now interact with the radial adjustment.In this home position, the adjustment device can, for example, be moved toward the tool or be located in a fixed position on the machine tool, so that when the tool moves to the home position, it automatically engages the adjustment device. This adjustment device can then be used to automatically operate the radial adjustment of the tool, thus fully automatically setting the next desired cutting diameter by radially displacing the cutting tool holder with the cutting element.

[0018] In the case of a tool which has a gear in the region of at least one spindle, a very advantageous further development of the adjusting device of the machine tool can be provided such that it has a gear driven by a stepper motor which, when the tool is in the home position, engages with the gear of the at least one spindle. The gear of the adjusting device can therefore be moved accordingly and in a precisely metered manner via the stepper motor. This gear meshes with the gear of the at least one spindle and thus ensures the radial adjustment of the cutting edge holder with the cutting element into the new desired position. The extent of the movement and thus the path of the radial adjustment can preferably be predetermined via a control of the tool mesh, e.g. using a CNC program.

[0019] According to an extremely advantageous development of this machine tool, it can further be provided that the adjustment device is additionally designed to also actuate the angle adjustment, if this is present in the tool.

[0020] A further very advantageous embodiment can further provide that the angle adjustment is also carried out by a stepper motor in the adjustment device of the machine tool, which directly or indirectly, for example via a gear element, such as a lever, an eccentric slide or the like, which preferably cooperates with the lever element of the angle adjustment of the tool.

[0021] A further very advantageous embodiment of the machine tool according to the invention can also provide for a supply of liquid lubricant to the tool via the chuck.

[0022] Further advantageous embodiments and developments of the tool according to the invention and of the machine tool also result from the exemplary embodiment, which is explained in more detail below with reference to the attached figures.

[0023] Showing: Fig. 1 shows a possible embodiment of a machine tool and a tool according to the invention in a schematic representation; Fig. 2 a rubber element with incisions as an example of the possible applications of the tool according to the invention; Fig. 3 a detail of the representation in Fig. 1 from a different perspective; Fig. 4 a possible embodiment of a cutting element in a partial section; Fig. 5 the cutting element according to Fig. 4 in a side view; and Fig. 6 the cutting element according to Fig. 4 in an alternative design

[0024] In the presentation of the Fig. 1 shows a machine tool 100 with a tool 1. The machine tool 100 comprises an indicated frame 101 with a drive 102 and a control 103. The drive 102 rotatably drives a shaft designated 105 and thus a chuck 104 which is connected in a rotationally fixed manner to the shaft 105 and serves to hold the tool 1. As indicated by the double arrow designated V, the drive 102 allows the spindle to be advanced or fed in the axial direction around its axis of rotation, in this case from top to bottom. At the same time, the drive unit with the drive 102 and the spindle 104 could be moved accordingly in the xy direction. Alternatively, a receiving table 106 can also be designed to be movable accordingly. In principle, both elements could also be moved.

[0025] As already mentioned, the chuck 104 holds the tool 1 and can drive it in rotation about a rotation axis A in order to cut a rubber element 2 positioned on the receiving table.

[0026] Tool 1 is used to cut the Fig. 2 again as an example. This consists, for example, of a cylindrical disc, such as can be used to seal cable penetrations from the inside to the outside of a building. The rubber element 2 in the Fig. The exemplary embodiment shown in Figure 2 has several concentric incisions E, which correspond to different diameters of available lines. These concentric incisions E are cut into the rubber material of the rubber element 2 over a large part of its thickness t, but not completely through. This has the advantage that the parts that are not needed can then be broken out on site to ensure a secure and reliable seal for the line routed through the rubber element 2. Such rubber elements 2 have a hardness of approximately 50 to 80 Shore A. The thickness t is typically 20 to 60 mm.

[0027] In order to make these concentric incisions E, the Fig. 1. A cutting element designated 4 is arranged on a cutting holder 3. This cutting element is accommodated in the cutting holder 3, for example clamped or screwed in, and has the actual cutting edge 5 at its end facing away from the cutting holder 3. This is in the Fig. 4 and Fig. 5 and can be realized, for example, via one or - as shown here - two ground facets 6.

[0028] To now Fig. To achieve the incisions E shown in Figure 2 in the rubber element 2, several tools with different diameters had to be used one after the other. However, the tool 1 according to the invention is now able to produce the various concentric circular incisions E in the rubber element 2 with one and the same tool 1, without the need for a tool change. Fig. The tool 1 shown in Figure 1 is designed such that it has one of the cutting elements 4 on a cutter holder 3. The cutter holder 3 itself is connected to the tool holder 10 via a radial adjustment 7. This radial adjustment 7 can, in principle, be designed in any desired manner, for example as a linear drive. However, it is particularly simple and efficient in that it has two counter-rotating spindles 9, which in the illustration of Fig. 1 are designated 9a, 9b, with the spindle 9a, for example, rotating clockwise and the spindle 9b correspondingly rotating counterclockwise. The two spindles, designated jointly by the reference numeral 9, are connected in a rotationally fixed manner to a gear 11 arranged in the region of the rotation axis A. Actuation of the gear 11 in a manner described in more detail later thus ensures a rotational movement of the spindles 9. The cutting edge holder 3 on the spindle 9a and an additional cutting edge holder 3' on the radially opposite spindle 9b are designed such that they have approximately the same weight. If the counter-rotating spindles rotate, the cutting edge holder 3 and its cutting edge holder 3', which ultimately serves as a counterweight 3', adjust analogously to one another, so that the tool 1 always remains in a balanced state, regardless of the radial position in which the cutting edge holder 3 is arranged.This possibility of adjusting the cutting element 4 via the radial adjustment 7 now makes it possible after cutting the first, for example the inner incision E in the representation of the . Fig. 2, to move the tool 1 out of the rubber element 2 in the feed direction V, to bring it into a home position and to rotate the gear 11 accordingly in order to adjust the cutting element 4 to a different distance from the rotation axis A and thus to be able to cut a different incision E in the next step, typically the one with the next larger diameter.

[0029] In the presentation of the Fig. This structure can be seen again in Figure 3 in a schematic section from the side. In addition to the cutting edge holder 3 and the cutting element 4, the tool holder 10 as well as the gear 11 and one of the spindles, here the spindle 9a, can be seen. An adjusting device 110 is also shown. In this adjusting device 110, a gear designated 107 is driven by a stepper motor 108 in accordance with the controller 103 of the machine tool 100. The adjusting device 110 is designed such that, in the home position of the tool 1, the gear 11 automatically meshes with the gear 107 of the adjusting device 110, or that the adjusting device 110 is moved towards it in the home position of the tool 1 in order to achieve engagement of the two gears 11, 107 with one another.Controlled by the controller 102, the stepper motor 108 in the adjustment device 110 is actuated such that the gear 108 rotates such that the desired adjustment of the cutting element 4 in the radial direction (i.e., perpendicular to the rotational axis A and the axial direction parallel to it) occurs. This prepares the tool for the next incision E. This is repeated until all incisions E have been produced. The next rubber element 2 is then placed on the receiving table 106, or the table is moved in the xy plane until the next rubber element 2 is located under the tool 1. Changing the tool 1 is not necessary here. If several similar rubber elements with incisions E of the same diameter are produced one after the other, the process can start at the innermost diameter of the first part produced, the next part produced at the outermost diameter, and so on.This additionally reduces the adjustment effort between the individual rubber elements 2 for the cutting element 4.

[0030] Both in the presentation of the Fig. 1 as well as in the representation of the Fig. 3 shows an angle adjustment 12 between the cutting holder 3 and the cutting element 4. This angle adjustment 12 allows the angle of the cutting element 4 or its cutting edge 5 to be adjusted to the tangential direction. In this way, the Fig. 4 and Fig. The cutting edge 5 shown in Figure 5 can be positioned so that it is aligned exactly tangentially to the circular incision to be made, and it can be readjusted if, for example, a misalignment has occurred or a different setting is desired.

[0031] Here too, it is possible to make this adjustment in the area of ​​the angle adjustment 12 using the adjustment device 110. This is shown in the illustration of the Fig. 3 below the gear 107, a stepper motor 111, which can adjust the angle adjustment 12 directly or preferably indirectly, for example via a worm drive, a lever element or the like, which is shown here very generally as a gear component 109. This can preferably be designed such that it enables rotation of the cutting element 4 about its vertical axis, i.e. the central axis of the longest extension of the typically rod-shaped cutting element 4. In order to be able to make an exact adjustment with the least possible forces, a lever element (not shown) can be provided, which is connected in a rotationally fixed manner to the angle adjustment 12 and can be used in particular to adjust the angle by means of the adjustment device 110.

[0032] In order to ensure safe and reliable cutting even at greater cutting depths of more than 10 mm, a fluid lubrication system supplied with fluid via the machine tool 100 is provided in the tool 1. The fluid is conveyed in a manner known per se via the chuck 104 and the tool holder 10 to the cutting element 4 or the cutting edge holder 3 and from there into the cutting element 4. There, and this is shown in the illustration of the Fig. 4, which shows the cutting element 4 in partial section, the liquid lubricant is supplied via a supply channel 8 into the area of ​​the two facets 6 of the cutting element 4. When the cutting element 4 is engaged in the rubber element 2, a liquid cushion of the lubricant will collect at the facet 6 and from there, provided sufficient liquid is supplied through the supply channel 8, the liquid will distribute itself in the area of ​​the cutting edge 5. This can also occur when the cut is already so deep that the rubber material lies all around the cutting element 4 and seals it off from the environment. Lubricant supplied from there would not reach the area of ​​the cutting engagement. This problem can be counteracted by the supply channel 8 to each of the facets 6.The lubricant is safely and reliably delivered to the area of ​​the cutting edge 5, thus enabling easy and high-quality cutting. The tool 1 is particularly suitable for cutting the rubber element 2 with the stated hardness of 50 to 80 Shore A. Of course, such a tool 1 is also suitable for processing rubber materials or rubber-elastic foams of other hardnesses, especially materials with very low Shore hardness, such as soft rubber materials or rubber-elastic foams.

[0033] In the illustration of the cutting element 4 in Fig. 5 this is compared to the representation in Fig. 4 is shown rotated by 90 degrees. It can be seen that in this direction, the cutting edge 5 is also comparatively small, since a corresponding grinding can also be carried out here. In addition to the reduction of cutting forces through the liquid lubrication, such a cutting element 4 also has an advantage with regard to the necessary cutting forces due to its comparatively small size of the cutting edge 5. In addition to the Fig. In principle, a central feed channel 8 would also be conceivable in addition to the two feed channels 8 shown in the partial section of the cutting edge 4a in Figure 4, which would be connected to the respective facet 6 by the grinding on both sides. Of course, a design with only a single facet 6 for forming the cutting edge 5 would also be conceivable.

[0034] The supply channel 8 can be arranged instead of in the surface of the facet 6, as in the Fig. 4 and Fig. 5, also end at their tip, for example following the cutting edge 5 in the cutting direction. This is shown in a view analogous to that shown in Fig. 5 in the Fig. 6. This allows sufficient lubricant to be introduced into the already made incision for the subsequent cut. This design also allows for a relatively slim cutting element 4, preferably with a rectangular or oval cross-section, whereby Fig. 6 the view of the wider side is shown. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 202 487 A1 [0002, 0004, 0007]

Claims

[1] Tool (1) for circular cutting of rubber (2) with at least one rod-shaped cutting element (4) which is accommodated in a cutting holder (3), with a tool holder (10) for connecting the tool (1) to an external drive (102) which is designed to rotate the tool (1) about a rotation axis (A), characterized by that a radial adjustment (7) is provided which is designed to displace the cutting holder (3) radially to the axis of rotation (A) in order to set a predetermined distance between the cutting element (4) aligned parallel to the axis of rotation (A) and the axis of rotation (A). [2] Tool (1) according to claim 1, characterized bythat the radial adjustment (7) has at least one spindle (9) aligned perpendicular to the axis of rotation (A), which engages with a toothing of the at least one cutting edge holder (3) in such a way that a rotation of the spindle (9) causes a radial movement of the cutting edge holder (3). [3] Tool (1) according to claim 2, characterized by that the spindle (9) is connected in a rotationally fixed manner to a gear (11). [4] Tool (1) according to claim 3 characterized by that two radially aligned spindles (9a, 9b) with opposing threads are provided, both of which are designed to be non-rotatable with the gear wheel (11), the spindles (9a, 9b) having the same geometric dimension, either two cutting edge holders (3) and cutting elements (4) or one cutting edge holder (3) and cutting element (4) and a counterweight (3') corresponding to these being arranged radially adjustable on each of the spindles (9a, 9b). [5] Tool (1) according to one of claims 1 to 4, characterized by that exactly one cutting holder (3) with one cutting element (4) is provided. [6] Tool (1) according to one of claims 1 to 5 characterized by that the at least one cutting element (4) or the at least one cutting holder (3) is designed to be angularly adjustable about an axis perpendicular to the axis of rotation (A) by means of an angular adjustment (12). [7] Tool (1) according to claim 6, characterized by that the cutting edge holder (3) has a lever element for angle adjustment. [8] Tool (1) according to one of claims 1 to 7, characterized by that the cutting element (4) has at least one supply channel (8) for a liquid lubricant to the part (5, 6) of the cutting element (4) which is in cutting engagement. [9] Tool (1) according to claim 8, characterized bythat the tool holder (10) and the cutting edge holder (3) comprise means for supplying the liquid lubricant to the supply channel (8). [10] Machine tool (100) with a chuck (104) receiving the tool holder (10) of the tool (1) and a drive (102) for rotating the tool (1) about the axis of rotation (A) and a feed device for moving the tool (1) along the axis of rotation (A), characterized by an adjusting device (110) which is designed to actuate the radial adjustment (7) of the tool (1) in a basic position of the tool (1). [11] Machine tool (100) according to claim 10, characterized by that the adjusting device (110) has a gear (107) which can be driven via a stepper motor (108) and which, in the basic position of the tool (1) according to one of claims 3 to 9, engages with the gear (11) of the at least one spindle (9). [12] Machine tool (100) according to claim 10 or 11, characterized by that the adjusting device (110) is additionally designed to actuate the angle adjustment (12) of the tool (1) according to one of claims 6 to 9. [13] Machine tool (100) according to claim 12, characterized by that the adjusting device (110) has a further stepper motor (111) which interacts directly or indirectly with the angle adjustment (12). [14] Machine tool (100) according to one of claims 10 to 13, characterized by that a device is provided for supplying a liquid lubricant via the chuck (102) into the tool holder (10) of the tool (1).

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