Workpiece stop

Abstract

Workpiece stop (10) for positioning a workpiece located in a clamping device (20) and in particular to be machined, comprising a stop element (1) against which the workpiece can rest in the position to be machined, and a stop holder (2) via which the stop element (1) can be aligned with the clamping device (20), wherein a fixing device (3) is provided for fixing the stop element (1) in its aligned position, characterized in that the fixing device (3) has a clamping sleeve (4) in which the stop element (1) is movably arranged, and a clamping nut (5) that can be screwed onto the clamping sleeve (4) with which the stop element (1) can be fixed in the clamping sleeve (4).

Description

[0001] The invention relates to a workpiece stop for positioning a workpiece located in a clamping device and in particular to be machined, with a stop element against which the workpiece can rest in the position to be machined and a stop holder via which the stop element can be connected to the clamping device in an alignable manner, wherein a fixing device is provided for fixing the stop element in its aligned position.

[0002] To machine a workpiece using a machining process, for example, drilling or milling, the workpiece must not only be precisely aligned with the often rapidly rotating tool, but it must also be secured as securely as possible in that aligned position after alignment to ensure reliable and rapid machining. Typically, the workpiece is clamped in a fixture such as a vice before machining. While the fixture can hold the workpiece securely, precise positioning is usually not possible using a suitable clamping device.

[0003] In this regard, it is known to use additional stop elements, which can be mounted on the vice via a stop holder and which can be fixed in an aligned position via a fixing device. The workpiece to be machined can then be placed in the clamping device, pushed forward to the stop element for the most precise positioning possible, and then fixed in the clamping device. Since the stop element determines the final position of the workpiece and is therefore very important for the identical positioning of all workpieces to be machined, especially in series production, the fixing device is of great importance. This is because the fixing device must ensure that the stop element does not slip even after extended periods of time, and the fixing device must also be designed in such a way that the position of the stop element is not impaired by the fixing.

[0004] A workpiece stop in which the stop element can be fixed in a position via a lever is shown, for example, in DE 20 2005 011 853 U1.

[0005] The invention has for its object to provide a workpiece stop which is characterized by a structurally simple design and by a reliable fixation of an aligned stop element even after a long period of use.

[0006] This object is achieved in a workpiece stop of the type mentioned at the outset in that the fixing device has a clamping sleeve in which the stop element is movably arranged, and a clamping nut which can be screwed onto the clamping sleeve and with which the stop element can be fixed in the clamping sleeve.

[0007] By using a clamping sleeve in which the stop element is movably arranged, precise and flexible positioning of the stop element can be ensured, particularly in the longitudinal direction of the stop element. The stop element can be guided through the clamping sleeve and positioned in the clamping sleeve before being fixed. Before the clamping nut is screwed onto the clamping sleeve, the stop element can be freely moved back and forth in the clamping sleeve in at least one direction, particularly in the longitudinal direction of the stop element or in the x-direction, and thus aligned. Once the clamping nut has been screwed on, relative movement of the stop element with respect to the clamping sleeve is no longer possible, but the stop element is immovably secured or fixed in the aligned position in the clamping sleeve.When the clamping nut is tightened, the stop element remains stationary, so the fixation does not affect the aligned position of the stop element. The precise positioning and fixation of the stop element ensures the most accurate positioning of the workpiece in the clamping device.

[0008] According to an advantageous development of the invention, the fixing device can fix the stop element frictionally, in particular in the manner of a collet. Thanks to the frictional fixation, the stop element can initially be continuously aligned and then reliably fixed in any position. The frictional connection or fixation also enables a very rapid change in the position of the stop element by releasing the fixation, moving the stop element, and re-fixing the stop element. Furthermore, the fixation in the manner of a collet allows for very secure fixation.

[0009] Furthermore, it has proven advantageous if the clamping sleeve has a conically tapered clamping section and a particularly cylindrical threaded section onto which the clamping nut can be screwed. The conically tapered clamping section of the clamping sleeve enables self-centering clamping of the stop element, which leads to improved stability and precision in the fixation of the stop element. The cylindrical threaded section facilitates screwing on the clamping nut and ensures even force distribution.

[0010] In a structurally advantageous embodiment of the invention, the clamping sleeve has a spring section arranged between the clamping section and the threaded section, which allows an elastic movement of the clamping section relative to the threaded section. Due to the spring section, the clamping section can deform elastically and thus reversibly in the radial direction with respect to a central axis extending centrally through the clamping sleeve when the clamping nut is screwed on. The threaded section is not deformed in the process. The spring section can be designed as a diameter recess. This means that the diameter of the threaded section and the diameter of the clamping section can be larger than the diameter of the spring section. Due to the smaller diameter, the spring section can allow an elastic movement or deformation of the clamping section connected to the spring section.

[0011] With regard to the structural design of the clamping section, it has proven advantageous if it has a plurality of slot-shaped recesses extending in the axial direction, which divide the clamping section into several, in particular four, clamping tongues. Axial means that the recesses extend in the axial direction to the central axis. The axial slot-shaped recesses in the clamping section enable a certain flexibility of the clamping sleeve and, in particular, permit an elastic movement of the clamping tongues created by the recesses in the radial direction to realize a frictional connection between the clamping tongues and the stop element. Thus, two clamping tongues are separated from one another by a recess. The individual clamping tongues can be connected to one another via the spring section or the threaded section. A division into four clamping tongues has proven advantageous.The four clamping tongues can thus be arranged at 90 degrees to each other in the circumferential direction, thus reliably securing the stop element around its circumference. However, more or fewer clamping tongues are also possible.

[0012] Furthermore, it has proven advantageous if the clamping nut screwed onto the threaded section can press the clamping tongues in a radial direction on the circumference of the stop element in order to fix it. The clamping nut can have an internal thread via which it can be screwed onto the external thread of the threaded section. When screwed on, the clamping nut can come into contact with the clamping section or with the clamping tongues on the circumference and the clamping tongues can thus press onto the stop element. To screw on the clamping nut accordingly, it can have a hexagonal interface, which makes it easier to screw on, for example, with a tool or alternatively by hand.

[0013] From a design point of view, it has also proven advantageous if the clamping nut has a conical clamping surface which comes into contact with the conical outer surface of the clamping section when the clamping nut is screwed onto the threaded section. The angle between the conical outer surface of the clamping section and the conical clamping surface can be identical, in particular essentially identical, so that when the clamping nut is screwed on, the clamping surface rests as flatly as possible on the outer surface of the clamping section or the outer surface of the clamping tongues. This can ensure reliable force transmission from the clamping nut to the clamping section. The clamping surface of the clamping nut can be arranged axially next to the threaded section so that the threaded section of the clamping nut can engage with the threaded section of the clamping sleeve and the clamping surface can be in contact with the clamping section.

[0014] With regard to assembly, it has also proven advantageous if the clamping nut can be screwed onto the threaded section from the direction of the clamping section. Orienting the clamping section so that the clamping nut can be screwed onto the clamping sleeve or onto the threaded section of the clamping sleeve from the direction of the clamping section facilitates access and handling, and overall user-friendliness during assembly. Furthermore, this design ensures a compact design of the workpiece stop, as the required installation space can be reduced.

[0015] In a preferred embodiment, the clamping nut has a central recess through which the stop element can extend. The clamping sleeve and the clamping nut can be arranged concentrically to each other, and the stop element can extend centrally through the clamping sleeve and also through the clamping nut. This allows for precise alignment of the stop element.

[0016] With regard to the stop element, it has proven advantageous if it is designed as a stop rod. The design of the stop element as a stop rod enables a simple and robust construction that can withstand high mechanical loads. Furthermore, the use of a stop rod can achieve precise positioning and reliable fixation, which then also leads to precise and reliable positioning of the workpiece. The stop rod can have a circular cross-section and the central axis can correspond to the axis of symmetry of the stop rod. Furthermore, the stop rod can also have other cross-sections, such as a polygonal, in particular a rectangular, cross-section. The workpiece can be pushed forward in the clamping device until it comes to rest against the stop rod, in particular on the end face.Although the contact area between the stop rod and the workpiece is quite small with this end-to-end contact, it is sufficient for very precise workpiece positioning. Furthermore, to increase the contact area, the stop element or stop rod can be bent or widened at the end. A connection to a stop element, which can be positioned very precisely via the stop rod and against which the workpiece can then strike, is also possible.

[0017] According to an advantageous development of the invention, the clamping sleeve has a fastening section via which the clamping sleeve can be screwed into the stop holder. The ability to screw the clamping sleeve via a fastening section enables quick and, in particular, even tool-free assembly and disassembly, which simplifies maintenance and replacement. The fastening section advantageously allows the clamping sleeve to be firmly and immovably connected to the fastening section, which can be important for precise positioning of the stop element. For this purpose, the stop holder can have a threaded bore, particularly in an end region, into which the clamping sleeve can be screwed. The fastening section can have an external thread for the connection.The fastening section can be arranged next to the threaded section of the clamping sleeve, so that the threaded section can be arranged between the clamping section and the fastening section. The clamping sleeve can thus have an elongated geometry overall, and this geometry can be arranged essentially symmetrically to the central axis. As an alternative to a screw connection, other connections can also be provided between the clamping sleeve and the fastening section; a one-piece connection is also possible.

[0018] Furthermore, it has proven advantageous to provide a contact ring, in particular an O-ring, against which the clamping nut can rest when screwed on. The contact ring can be arranged between the clamping nut and the stop holder. The arrangement of the contact ring between the clamping nut and stop holder can lead to improved force transmission and stabilization of the entire clamping sleeve. Furthermore, the contact ring can serve as an additional safety device that prevents the clamping nut from loosening under vibration loads and thus increases operational reliability. The contact ring can be made of an elastic material for this purpose, and the clamping nut can elastically deform the contact ring when it is fully screwed onto the clamping sleeve. Furthermore, the contact ring can achieve an even pressure distribution on the stop holder, which extends the service life of the components and increases maintenance intervals.Furthermore, the support ring can prevent chips generated during workpiece machining from getting close to the thread. This prevents chips from becoming trapped in the thread.

[0019] According to a further advantageous embodiment of the invention, the stop holder is detachably connectable, in particular screwable, to the clamping device via a fastening element, in particular a screw. The stop element can thus be directly connected to the clamping device via the stop holder, so that the aligned position relative to the clamping device is fixed and a movement of the clamping device does not lead to a change in the aligned position of the stop element. Nevertheless, the screw connection can also be loosened, which allows for flexible adjustment overall.

[0020] Furthermore, it can be provided that the stop holder has an elongated hole through which the fastening element can extend, wherein the stop holder is rotatably and translationally movable relative to the fastening element in order to position the stop element. The stop holder can be moved in the longitudinal direction of the elongated hole and thus translationally through the elongated hole, provided the fastening element has not yet been tightened. Furthermore, rotational alignment can also be enabled. By moving the stop holder accordingly, the stop element can be moved transversely to its longitudinal axis, i.e. in the y- and z-directions, and when the clamping nut is loosened, the stop element can be moved in the x-direction. The x-direction thus corresponds to the longitudinal direction of the stop element. Due to the elongated hole, the stop holder can have an elongated geometry.The longer the slot, the larger the area in which the stop element can be positioned over the stop holder.

[0021] Finally, it has proven advantageous if the fastening element extends through the stop holder and a spacer, in particular a spacer sleeve. The spacer can be arranged between the stop holder and the clamping device, so that a certain axial distance between the stop holder and the clamping device is made possible via the spacer. This then also makes it possible, for example, for the stop element to be arranged away from the clamping device in its aligned position, which overall increases flexibility. By designing it as a spacer sleeve, the spacer element can rest against the clamping device and the stop holder at its ends, and the fastening element can extend through the spacer, in particular centrally. Furthermore, it can also be provided that the fastening element extends off-center through the spacer or is connected to the spacer off-center.The spacer can be connected to the clamping device on one side, and the fastening element can be connected to the spacer on the other side, particularly via a screw connection. If the fastening element is arranged off-center, the position of the stop holder, including the stop element, can be varied by rotating the spacer, which further improves the overall adjustment of the tool stop. The spacer can thus be connected to the spacer sleeve eccentrically or in the manner of an eccentric.

[0022] Further details and advantages of the invention will be explained in more detail below with reference to the accompanying drawings, in which: Fig. 1 a perspective view of a clamping device with a workpiece stop arranged thereon; Fig. 2 a side view of the workpiece stop according to Fig. 1; Fig. 3 a perspective view of the workpiece stop according to Fig. 2; Fig. 4 a side view of the workpiece stop without stop element with unscrewed clamping nut.

[0023] The representation of the Fig. 1 shows a substantially block-shaped clamping device 20 with two displaceably mounted clamping jaws, between which a workpiece (not shown) can be clamped prior to machining. Although the position of the inserted workpiece between the two jaws is predetermined in the y and z directions, the workpiece is not fixed in the x direction before the jaws are tightened in the x direction. To enable precisely predefined positioning of the workpiece in all spatial directions, a workpiece stop 10 is provided, which is detachably connected to the clamping device 20 via a screw connection. The workpiece stop 10 comprises a rod-shaped stop element 1, which is displaceably mounted in a clamping sleeve 4 in the x direction or along the central axis of the stop element 1.This bearing allows the stop element 1 to be initially aligned in the x-direction, so that the end of the stop element 1 represents a stop point for the workpiece to be aligned. The workpiece can then be precisely positioned in the x-direction using the stop element 1. After positioning, the clamping jaws can be tightened, securing the workpiece with frictional engagement so that it cannot move during machining.

[0024] Furthermore, the stop element 1 can also be aligned in the y- and z-direction relative to the clamping device 20 via the stop holder 2. The stop holder 2 has a slotted hole 2.1 for this purpose, which is shown in the illustration of the Fig. 3. The fastening element 6, which is designed as a screw and is screwed into the clamping device 20 at the end, extends through the slot 2.1. In addition, a spacer 7, which is designed as a sleeve, is provided, which has a cylindrical geometry and is arranged between the clamping device 20 and the stop holder 2, as shown in the illustration of Fig. 1. The head of the screw or fastening element 6 now rests on the outer surface of the stop holder 2, so that the fastening element 6 presses the stop holder 2 in the axial direction against the spacer 7. When the fastening element 6 is tightened, the stop holder 2 is pulled against the spacer 7, creating a frictional connection and the stop holder 2 can then no longer be moved.

[0025] Before the fastening element 6 is tightened, the stop holder 2 can be aligned relative to the clamping device 20 in the y- and z-directions by a translational movement in the longitudinal direction of the elongated hole 2.1 and by a rotational movement around the fastening element 6. This also allows the stop element 1 to be positioned as desired in the yz-plane. The only limits are set by the length of the stop holder 2 or by the length of the elongated hole 2.1.

[0026] Once the stop holder 2 and thus also the stop element 1 have been positioned in the yz-plane, they can then be aligned in the x-direction and then fixed in the x-direction by a fixing device 3. The design of the fixing device 3 is best illustrated in the illustration of the Fig. 4. The fixing device 3 comprises a clamping sleeve 4, through which the stop element 1 can extend centrally, as is also shown in the illustrations of the Fig. 2 and Fig. 3. In addition, a clamping nut 5 is provided, with the aid of which the stop element 1 can be clamped in the clamping sleeve 4 in the axial direction or in the x-direction.

[0027] The representation of the Fig. The central axis D shown in Figure 4 corresponds to the longitudinal axis or the axis of symmetry of the stop element 1, so that the stop element 1, the clamping sleeve 4 and the clamping nut 5 are concentrically aligned with each other. Once the stop element 1 has been manually aligned in the x-direction so that the stop surface is then in the desired position, the clamping nut 5 can be pushed onto the clamping sleeve 4 and screwed to the threaded section 4.2. This is shown in the illustration of the Fig. 4 is indicated by the two dotted arrows.

[0028] In the axial direction, the clamping sleeve 4 has, in addition to the threaded section 4.2, a clamping section 4.1, which in turn has four clamping tongues 4.11 arranged circumferentially and extending in the axial direction. The clamping tongues 4.11 are connected to the threaded section 4.2 via the spring section 4.3, which is designed as a constriction, and these have a conical outer surface, as shown in the illustration of the Fig. 4. In the interior, the clamping section 4.1 or the clamping tongues 4.11 have a substantially cylindrical geometry, which can therefore lie almost completely against the outside of the spacer 1.

[0029] If the clamping nut 5 is now screwed onto the threaded section 4.2, a conical clamping surface arranged inside the clamping nut 5 comes into contact with the conical outer surface of the clamping tongues 4.11, which results in the clamping tongues 4.11 being elastically deformed radially in the direction of the central axis D. The spring section 4.3 primarily ensures the elastic movement of the clamping tongues 4.1 relative to the fixed threaded section 4.2.

[0030] Due to the elastic deformation, the clamping tongues 4.11 are pressed circumferentially against the stop element 1, thus creating a frictional connection between the clamping tongues 4.11 and the stop element 1. This frictional connection then prevents movement of the stop element 1 in the x-direction, so that the stop element 1 is fixed in the aligned position and can then no longer be moved. In order to move the stop element 1 again, it is necessary to turn the clamping nut 4 back a little from the threaded section 4.2, whereby it can be turned as shown in the Fig. 4 is moved to the left, thereby reducing the pressure on the clamping tongues 4.11 and thus also on the stop element 1. From a certain point, the stop element 1 can then be moved back and forth by hand in the x-direction in the clamping sleeve 4 in order to realign it.

[0031] To connect the clamping sleeve 4 to the stop holder 2, the stop holder 2 has a bore with an internal thread in the upper area and at a distance from the elongated hole 2.1, into which the clamping sleeve 4 can be screwed. Thus, in the axial direction, the clamping sleeve 4 has, next to the threaded section 4.2, a fastening section with an external thread and a slightly smaller diameter than the threaded section 4.2, via which the clamping sleeve 4 can be screwed into the stop holder 2.

[0032] Furthermore, the illustrations also show an elastically deformable abutment ring 8, which is arranged in the area between the threaded section 4.2 and the fastening section on the clamping sleeve 4. When the clamping nut 5 is screwed onto the clamping sleeve 4, it rests against the end of the abutment ring 8 and elastically deforms it to a certain extent. Due to the elastic deformation, the abutment ring 8 can provide a certain axial preload, which prevents the clamping nut 5 from accidentally loosening, even after extended periods of use.

[0033] Overall, the invention described above allows a stop element 1 to be positioned very precisely and safely in a structurally comparatively simple manner, so that a highly precise positioning of the workpiece and the associated good machining quality can be ensured. LIST OF REFERENCE SYMBOLS 1 stop element 2 stop holders 2.1 Slot 3 Fixing device 4 clamping sleeve 4.1 Tension section 4.11 Clamping tongue 4.2 Threaded section 4.3 Spring section 5 clamping nut 6 Fastening element 7 spacers 8 Investment ring 10 Workpiece stop 20 clamping device D Central axis 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 20 2005 011 853 U1

[0004]

Claims

[1] Workpiece stop (10) for positioning a workpiece located in a clamping device (20) and in particular to be machined, with a stop element (1) against which the workpiece can rest in the position to be machined, and a stop holder (2) via which the stop element (1) can be connected to the clamping device (20) in an alignable manner, wherein a fixing device (3) is provided for fixing the stop element (1) in its aligned position, characterized by that the fixing device (3) has a clamping sleeve (4) in which the stop element (1) is movably arranged, and a clamping nut (5) which can be screwed onto the clamping sleeve (4) and with which the stop element (1) can be fixed in the clamping sleeve (4). [2] Workpiece stop according to claim 1, characterized by that the fixing device (3) can fix the stop element (1) frictionally, in particular in the manner of a collet. [3] Workpiece stop according to one of claims 1 or 2, characterized by that the clamping sleeve (4) has a conically tapered clamping section (4.1) and a particularly cylindrical threaded section (4.2) onto which the clamping nut (5) can be screwed. [4] Workpiece stop according to claim 3, characterized by that the clamping sleeve (4) has a spring section (4.3) arranged between the clamping section (4.1) and the threaded section (4.2), which allows an elastic movement of the clamping section (4.1) relative to the threaded section (4.2). [5] Workpiece stop according to one of claims 3 or 4, characterized by that the clamping section (4.1) has a plurality of slot-shaped recesses extending in the axial direction, which divide the clamping section (4.1) into a plurality, in particular four, clamping tongues (4.11). [6] Workpiece stop according to claim 5, characterized bythat the clamping nut (5) screwed onto the threaded section (4.2) can press the clamping tongues (4.11) in the radial direction on the circumference of the stop element (1) in order to fix it. [7] Workpiece stop according to one of claims 3 to 6, characterized by that the clamping nut (5) has a conical clamping surface (5.2) which comes into contact with the conical outer surface of the clamping section (4.1) when the clamping nut (5) is screwed onto the threaded section (4.2). [8] Workpiece stop according to one of claims 3 to 7, characterized by that the clamping nut (5) can be screwed onto the threaded section (4.2) from the direction of the clamping section (4.1). [9] Workpiece stop according to one of the preceding claims, characterized by that the clamping nut (5) has a central recess through which the stop element (1) can extend. [10] Workpiece stop according to one of the preceding claims, characterized bythat the stop element (1) is designed as a stop rod. [11] Workpiece stop according to one of the preceding claims, characterized by that the clamping sleeve (4) has a fastening section (4.4) via which the clamping sleeve (4) can be screwed into the stop holder (2). [12] Workpiece stop according to one of the preceding claims, characterized by a contact ring (8), in particular an O-ring, against which the clamping nut (5) can rest in the screwed-on position, wherein the contact ring (8) is arranged between the clamping nut (5) and the stop holder (2). [13] Workpiece stop according to one of the preceding claims, characterized by that the stop holder (2) can be releasably connected, in particular screwed, to the clamping device (20) via a fastening element (6), in particular a screw. [14] Workpiece stop according to one of the preceding claims, characterized bythat the stop holder (2) has an elongated hole (2.1) through which the fastening element (6) can extend, wherein the stop holder (2) is rotatably and translatorily movable relative to the fastening element (6) for positioning the stop element (2). [15] Workpiece stop according to claim 14, characterized by that the fastening element (6) extends through the stop holder (2) and a spacer (7), in particular a spacer sleeve.

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