SI21128A - Device for location defined clamping of machined pieces in the working area of a processing machine - Google Patents

Abstract

The device features a clamping head (1) and a detachable machined piece holder (25) attached to it. The primary positioning means (22, 23) on the clamping head (1) and the secondary positioning means (29, 30) on the machined piece holder (25) interact two by two as guiding elements and the machined piece holder (25) is positioned in the x, y-axis and under a right angle regarding the clamping head (1). The linking device holds the machined piece holder firmly by positioning means in a fixed position on the clamping head. In order to provide the highest resistivity against the rotating torque occurring during operation, the primary positioning means include conical centring plugs (22), and the secondary positioning means feature grooves in the form of a two-level groove (30) featuring two steps. The edges reaching inside the groove (30) are at a distance, which is slightly smaller than the width of the centring plug (22). The clamping device (12, 14, 18, 28) includes clamping elements (18, 28) with the clamping force lines of operation located on or in the area of the virtual cylinder surface (MF) parallel to the z-axis, crossing the primary (22, 23) and secondary (29, 30) positioning means.

Description

WORKING IN THE WORKING AREA, comprising the first positioning means of a conical centering pin (22) and the second positioning means of recess in the form of a two-stage groove (30) having two steps in which the projecting edges (30) have interconnected spacings which is slightly smaller than the width of the centering pin (22), and the clamping device (12, 14, 18, 28) comprises clamping bodies (18, 28) whose lines of action of the clamping forces lie in or in the area conceived, with the Z axis parallel, the first (22, 23) and second (29, 30) positioning means of the intersecting sheath (MF) of the cylinder.

Fig. 21128 A

-1Erowa AG Reinach, Switzerland

The device for positionally defined workpiece clamping in the work area of the machine tool

The present invention relates to a device for positionally defined mounting of a workpiece in the working area of a machine tool, with

clamped head that it is fixed in the workplace area obde1ova1nega machine a, and carriers workpiece, which J ^e fasten iv on clamped head and which him on the latter i clamp, dO

introductory part of claim 1.

Such devices are known and mainly involve the machining of prepared workpiece with high precision. It is also particularly important to ensure that the clamping accuracy is reproducible. In other words, the workpiece attached to the workpiece carrier should be capable of being re-clamped in the workpiece carrier by the adapted clamping head, so that the workpiece always assumes a precisely defined necessary position in the X, Y, Z directions, as well as in relation to the angular orientation with respect to the Z axis, for example when the workpiece carrier is to be clamped on different machine tools, each of which is provided with a suitable clamping head, for sequential processing or at measuring and testing stations also equipped with a corresponding clamping head.

Such a device is described, for example, in EP-A1-0 255 042. The device there has two projecting laths projecting beyond the surface of the clamping head, which have receiving surfaces for directional positioning of the workpiece carrier in directions X and Y. Further four are provided across the surface of the clamping head The projecting tool holder has a piano surface which is designed to fit on the front surface of the aforementioned plugs. In addition, there are two anti-centering slots in the tool holder with centered laths with recessed elastic lips to support the laths provided. Lastly, the tool holder is provided with a central hole for receiving the pull pin, which is used to convey the required clamping force to position the workpiece carrier correctly. In this case, the clamping head has a centrally arranged ball closure that cooperates with this pull-pin.

The disadvantage of such well-known devices is that they are relatively unstable, especially in the case of processing larger or larger ones. heavier workpieces. As such, they cannot take over any excessive torques and torques that occur especially when machining by cutting. However, in many cases it is not desirable to increase the device to provide better stability in spatial circumstances.

On the basis of all this, the object of the invention is to perfect the workpiece positioning device in the working area of the machine in the introductory part of claim 1 of said type so that the workpiece carrier is fixed firmly on the clamping head and thus the workpiece prepared for machining is kept constant. positioning accuracy, such as repeated shooting and clamping, while retaining the desired small dimensions, can assume larger zirniir.e and

-3 torque without changing the position of the workpiece holder and the head clamp.

According to the invention, this task is solved with the device in the introductory part of claim 1 of a particular type by the measures described in the characteristic part of this claim.

The first-mentioned characteristic makes it possible for clamping forces to appear exactly where they can develop their greater impact, namely in the area of first and second positioning means. As a result, there is hardly any or very little for the torque and torque of the essential levers, which explains the great resistance of the device of the invention to inadvertently changing the position caused by the resulting torques and torques.

High resistance to inadvertent change of position, which occurs due to under load of torque and torque, is supported by or. the second-mentioned feature of claim 1, wherein the first positioning means have tapered centering plugs and the second positioning means are in the form of a two-step groove having two steps, the projecting edges of the groove being at a distance of less than a little the width of the centering pin measured between those points that contact the edges with the workpiece carrier clamped in the clamping head.

eye performance improved

In order to provide or. further increasing the desired high resistance to change of position due to the influence of torque, in the preferred embodiment, it is provided that the action lines of the clamping forces of the clamping bodies do not lie inside, but rather outside the intended, Z-axis of the parallel mating surface of the cylinder intersecting the first and other positioning assets. This is advantageous in the embodiment of the invention in a substantially cylindrical clamping head, and essentially as a hollow cylinder for designed tool carriers, for example, in that the clamping bodies comprise distributed spaced clamping balls arranged around the circumference of the clamping head, which are defined for engagement with the inner surfaces of the tool carrier. spaced, contracted annular grooves.

In order that the device according to the invention also accepts, for example, long-pointed workpieces in which only a certain area is cultivated, it is provided, according to a further feature of the object of the invention, that both the clamping head and the tool carrier have central holes for receiving such long-stressed workpieces.

In other respects, the preferred details and embodiments of the subject matter of the invention are enumerated in dependent claims 2 to 17.

In the following, an embodiment of the device according to the invention is described in more detail with reference to the accompanying drawings. The sketches are as follows:

FIG. - the carrier workpiece v space which presentation, FIG. 2 the carrier workpiece with FIG. 1 in the view of below, FIG. 3 the carrier workpiece v section Po lines III-III s

FIG. 2,

FIG. 4 detail of the intake hole of the centering hole and the centering pin in cross section and enlarged accordingly,

FIG. 5 clamping head in the spatial representation,

FIG. 6 is a clamping head of FIG. 5 in floor plan,

FIG. 7 is a cross-sectional view of the clamping head along line VII-VII of FIG.

6,

FIG. 8 is a cross-sectional view of a clamping head along line VIII-VIII s

FIG. 6, and

FIG. 9 is a cross-sectional view of the clamping head along the line ΙΧ-ΙΧ with FIG.

.

In the drawings, the device for positioning the workpiece mounting position of the workpiece at the workplace of the workpiece comprises, on the one hand, the workpiece carrier (FIGS. 1 to 3) as a whole and, on the other, the clamping head (FIG. 1) on the other. 5 to 9). While the clamping head 1 is essentially designed to be fixed in the working area of the workpiece, the workpiece carrier 25 is used for receiving for machining the workpiece. It is understood that the term workpiece is to be understood in a purely general sense; in particular, it may also be a tool to be machined, such as an electrode for a grinding machine.

The design of the workpiece carrier 25 is shown in FIGS. 1 to 3. As shown in particular in FIGS. 1 and 3, as a single piece, the workpiece carrier 25 comprises a circumferential portion 2S with substantially cylindrical or cylindrical sections. a tubular structure and a substantially annular flange portion 27. The inner diameter of the circumferential portion 26 thus substantially corresponds to the outer diameter of the main part 4 of the clamping head 1, of course with a reasonable slot, so that the workpiece carrier 25 can be inserted onto the clamping head.

The circumferential portion 26 of the workpiece carrier 25 has an annular groove 28 on its inner surface, the two lateral walls of which extend so inclined that it opens openly to the inside. In other words, this annular groove essentially has a V-section. The details of this annular groove are further written.

The flange portion 27 of the workpiece carrier 25 has a projecting annular arm 29 against the inner circumference of the workpiece 29. The median diameter of this workpiece 29 thus substantially corresponds to the diameter of the circle where the four centering studs 22 of the main part 4 are arranged. the front surface of the shoulder 29 is the piano convoluted and serves as a reference Z, which is designated to cooperate with the aforementioned planar sections 23 of the surface 24 of the main portion 4. Further, four recesses 30 are arranged in said forehead shoulder 29, the design of which will be further elaborated and designed to cooperate with four centering plugs 22 projecting out from the surface 24 of the main part 4 of the clamping head 1, which will be presented in greater detail.

Although the four abovementioned studs 22 and the four recesses thereof 30 are provided for in the embodiment described above, it is understood that three, six, eight or more, each of the subset of the Hirth tooth can be predicted, and the recess 30 in order to provide positioning of the workpiece carrier 25 with respect to the clamping head 1 in the X and Y directions and in the angular direction.

The clamping head designated for engagement with such a workpiece carrier 25 is shown in FIGS. 5 to 9. As best seen from the cross sections - FIG. 7 to 9, the clamping head is essentially a three-part design comprising the base element 2, the middle part 3 and the main part 4. The basic element in the present embodiment has the form of a circular disc with a center opening 5, the meaning of which will be explained later. The middle part 3, which is provided with a center aperture 6 of equal light diameter and is substantially cylindrical or cylindrical. The tubular structure is connected via screws 7 to the base element 2. The main part 4, which also has a central opening 8 of the same light diameter, has, in the last case, essentially a pot or. hat resembling a structure and having an inner diameter greater than the outer diameter of the middle portion 3. The main part 4 is connected on one side by screws 9 with the base part 2 and on the other via screws 10 with the middle part 3. Lastly, the main part 4 is equipped with a contracted annular arm 20 located below the holes 19, into which a seal 21 is engraved.

The above design provides an extremely rigid and bent clamping head of a housing type that can be easily disassembled for maintenance purposes.

The upper surface 24 of the main portion 4 is, first of all, provided with four outwardly projecting centering plugs 22, which are essentially prismatic and are arranged in a cross in the edge region of the upper surface 24 of the main portion. The two centering studs facing each other 22 thus determine the course of the X axis, while the other two centrally facing studs defining each other perpendicularly to the Y axis. The axes X and Y intersect at right angles to both running Z axes (FIG. 7 to 9). In each case, at least both circumferentially opposite the other side surfaces of the centering studs 22 are slightly inclined towards the Z axis, which will be further explained in the following.

Secondly, the upper surface 24 of the main part 4 has four planar sections 23 which, in the present case, extend radially between the two centering studs 22 in each case and are slightly elevated relative to the surface 24 of the main part 4. These flat sections 23 serve as a Z-reference, which will be further explained in the following.

Sketch of FIG. 4 shows a detail, on a larger scale, of a cross-section through a recess 30 and a centering pin 22. The recess 30 is made as a two-stage groove and has steps 31a, 31b. As mentioned above, the centering plugs 22 are slightly conical, with at least two circumferentially opposite each other of the lateral faces 22a of the centering studs 22 toward the Z axis, each slightly inclined, practically by a few degrees, preferably between 3 ° and 3 °. Inside the groove 30, the projecting edges 32a, 32b of the steps 31a, 31b are suitable for positioning, since their spacing is slightly smaller than the width of the centering pin 22, measured between the two points which contact the edges 32a of the workpiece holder 1 with the workpiece 25a. , 32b.

The mutual dimensions of the clamping head 1 and the workpiece carrier 25 are selected so that the result is the following: if the workpiece carrier 25 is freely inserted onto the clamping head 1, the centering plugs 22 are recessed with the recesses 30, with the lateral surfaces 22a of the centering plugs 22 being in line. to the edges 32a, 32b of steps 31a, 31b. At the end of the piano, the convoluted front surface of the shoulder 29 of the workpiece carrier 25 does not extend slightly to one surface 24 of the main part 4 and does not yet fit the serving flat sections 23 of the clamping head 1. Earlier than this, there are gaps of several hundredths of a mm between the front face of the shoulder and the surface of sections 23. On the other hand, the positioning of the workpiece carrier 25 towards the clamping head 1 in the X direction as well as with respect to the angular position is fixed and finished.

Therefore, when the workpiece carrier 25 is mounted on the clamping head 1 and positioned in the Χ / Υ direction and with respect to the angular position, the clamping device is activated, which will be further described by tightening the carrier 26 to the clamping head 1, which in practice occurs with a force of about 2,000 to 3,000 N. Under the influence of this clamping force, steps 31a, 31b are in the region of their edges

32a, 32b elastically deform i.s. to such an extent that the shoulder surface 29 of the workpiece carrier 25 extends into the slightly elevated planar sections 23 of the clamping head 1. The workpiece carrier 25 is also positioned in the Z direction in the direction of Z.

The clamping force required by the workpiece carrier 25 and the embodiment provided for the axial interconnecting of the clamping head 1 occurs as follows.

By the fact that there is already a mentioned difference in diameters between the middle part 3 and the main part 4 of the clamping head 1, there is an annular space 11 between the two elements, the seals of which are unmarked more closely and the seals shown in the drawings (FIGS. 7 to 9). Inside the annular space 11, the annular piston 12 is so arranged that it is movable in the direction of the Z axis of the clamping head 1. The annular piston 12 has bag holes 13, which are evenly distributed around the circumference thereof and adapted to receive the clamping springs 14. the springs 14 rest against the lower face of the main portion 4 and aim to push the annular piston 12 down. Further, the annular piston is provided with an outer, sheath groove 15 of which is lower

-1010 the lateral wall is so inclined that it falls towards the outside; this groove 15 serves to partially receive a set of coupling balls 18.

Under the annular piston 12 there remains a free annular space 16 that cooperates with the connecting hole 17 located in the base plate. Through this connecting hole 17, it is possible to fill the annular space 16 with compressed air which presses on the annular piston 12 and moves it upwards against the force of the spring 14.

The main part 4 has radial holes 19, the diameter of which essentially corresponds to the diameter of the coupling balls 18, and which are defined for receiving these balls 18. The height of the holes 19 and the height position of the closed annular groove 15 are thus mutually determined such that they are in holes 19 the inserted balls 18 may sink into the annular groove 15 when the compressed air-loaded annular piston 12 is moved against the force of the spring 14 to its upper dead position, the plunger being such that the coupling balls 18 no longer protrude beyond the outer circumference of the main portion 4.

The axial position of the annular groove 28, i.e. the altitude position with respect to the Z axis is so determined that, as shown schematically in FIG. 3, the coupling balls 18 may be inserted into the groove 28 when the workpiece carrier 25 is freely mounted on the clamping head 1, i.s. such that the spheres 18 are offset with respect to the axially running plane S-S of the symmetry of the annular groove 28 down. In other words, for the workpiece head 1 freely mounted on the workpiece carrier 25, the plane of symmetry S-S (FIG. 3) is located slightly above the center in the holes 19 of the middle portion 13 of the inserted balls 18.

-1111

The axial position of the annular groove 28 in the workpiece carrier 25 is so defined that the coupling balls 18 of the clamping head 1 can be inserted into the groove 28 when the workpiece carrier 25 is freely inserted onto the clamping head 1, with the plane of symmetry of the annular groove 28 being slightly above the center of the holes 19 of the middle part 3 of the inserted clamping balls 18. In the second aspect, in order to allow the workpiece carrier 26 to attach to the clamping head 1 freely at all, the clamping balls 18 of the clamping head 1 must be in their rearwardly drawn position. This happens (cf. FIGS. 7 to 9) that the annular space 16 under the annular piston 12 is compressed by compressed air, so that the annular piston 12 is moved upwards against the force of the spring 14. In this way, in the annular piston 12, the annular groove 15 comes in an aligned position with the balls 18 so that the latter can be recessed into the groove 15 and do not project out over the surface of the middle part 3 of the clamping head 1.

Therefore, when the workpiece carrier 25 is mounted on the clamping head 1 and positioned in the Χ / Υ direction and relative to the angular position, the overpressure in the annular space 16 is released so that the annular piston 12 is moved down under the influence of the spring 14. 3 threads, the coupling balls 18 are pushed into the annular groove 28 of the workpiece carrier 25. Through the aforementioned little asymmetrical milling position between the balls 18 and the annular groove 25 and through the V-cross-section of the latter, the workpiece carrier 25 is drawn to the clamping head 1 so that, as mentioned above, the shoulder surface 29 of the workpiece carrier 25 contacts the slightly elevated planar sections 23 clamping heads 1. With this, the workpiece carrier 25 is also positioned in the Z-direction against the clamping head 1 and the clamping operation is completed.

From the above embodiments, it follows that in parallel with the direction With the acting clamping force on the workpiece carrier 25,

-1212 coupling balls 18 transferred in coupling sense i.s. in the present case, twelve around the circumference of the middle portion 3 of the clamping head 1 are distributed in places. In other words, all the clamping force applied to the workpiece carrier 25 is the sum of twelve individual partial components of the clamping force, which are transmitted by one of the spheres 18. The action lines of these partial clamping force components lie on the cylindrical sheathing plate MF (FIGS. 7 to 9) which, depending on the selected dimensioning of the clamping head 1 and the workpiece carrier 25, and depending on the precise position of the centering studs 22, the recesses 30 and the shoulder surface 29 pass through these elements 22, 30, 29, and thus intersect, or extend directly adjacent of these elements, expediently little beyond. This ensures that the clamping force acts where it is actually needed, which further contributes to the fact that otherwise the bending load on the workpiece carrier is drastically reduced or reduced. we completely avoid them. Moreover, during machining of workpieces, the acting torques are significantly better captured than is the case with conventional central clamping.

It is understood that, instead of compressed air, the annular piston 12 can also be hydraulically loaded.

The recesses 30 in the workpiece carrier 25 are finely molded by means of plastic molding, such as embossing. This gives very high precision, even when it comes to batch production. Massive centering plugs 22 with little hinged hinges, in conjunction with the recesses 30 into which they enter, make it possible to carry very large rotational torques.

The stability and rigidity of the workpiece clamping head / workpiece carrier in the re-condition is also compounded by the fact that the workpiece carrier, including its centering elements in

-1313 X, Y, Z and angular directions, designed as one piece. Essentially like a pot or a hat of the designed workpiece carrier structure 25, the essential parts of the clamping head 1 are secured during operation, in particular the dirt 22, 23, 30 being well protected against dirt. This protection is further enhanced by the seal 21 (cf. FIGS. 7 to 9) on the upper side of the shoulder 20, which is supported by the lower front edge of the outer part 26 of the workpiece carrier 25.

The aforementioned central holes 5, 6 and 8 in the base plate, the middle part 3 and the main part 4 of the clamping head in connection with the generally annular structure of the workpiece carrier 25 allow the workpiece to be tensioned and machined also. For example, it is possible to insert the leaf portion of the turbine blade into the holes mentioned above to process its clamping part, i.e. 'fish bone' (German Tannenbaum).

If the central opening of the clamping system can be dropped, it is possible to provide for an additional, centrally arranged clamping device to further increase the clamping force exerted on the workpiece carrier 25, or to distribute centrally a second, independent clamping system of a known type; was suitable for straining smaller objects.

Authorized by: Patent Office d.o.o. Ljubljana

For her: Vinko Skubic, BSc, Pat. for myself.

Claims (17)

Patent claims A device for positionally defined workpiece clamping in the work area of a machine tool, with a clamping head (1) fixed in the work area of the machine tool and a workpiece carrier (25) that is fastened to the clamping head (1) and which it is engaged on the latter, further by the first positioning means (22, 23) on the clamping head (1) and other positioning means (29, 30) on the workpiece carrier (25), which cooperate two and two, respectively, and which support ( 25) position the workpiece in three mutually at right angles to the coordinate axes (X, Y, Z) and at the correct angle with respect to the clamping head (1), and with the clamping device (12, 14, 18, 28), the clamping force of which the support The workpiece holds the positioning means against a fixed position on the clamping head, characterized by at least one of the following two characteristics: • the first positioning means have tapered centering plugs (22) and the second positioning means have recesses in such a two-stage groove (30) having two steps (31a, 31b) whose projecting edges (32a, 32b) have projections inside a spacing of less than the width of the centering pin (22), measured between the respective locations, which contact the edges (32a, 32b) of the workpiece with the workpiece carrier (25); and • the clamping device (12, 14, 18, 28) comprises clamping bodies (18, 28) whose lines of action of the clamping forces lie substantially in or in the area conceived, with the Z-axis parallel, the first (22, 23) and the second (29, 30) The positioning means of the intersecting sheath (MF) of the cylinder. -1515 Apparatus according to claim 1, characterized in that the centering plugs (22) are arranged perpendicularly on the surface of the clamping head (1), each at least two circumferentially opposite each other to the lateral face (22a) of the centering plugs (22). ) with respect to the Z axis inclined. Apparatus according to claim 2, characterized in that the inclination of the lateral surfaces (22a) is between 3 ° and 9 °. Apparatus according to claim 1, characterized in that the first positioning means further extend to the edge of the surface of the clamping head (1), the extending, flat surfaces (23). Device according to one of Claims 1 to 4, characterized in that the recesses (30) are embedded in the inner side essentially as a hollow cylinder of the designed support (25) of the projecting projecting shoulder (29) of the flange dels (27) of the support (25). ) of the workpiece, the position of which corresponds to the position of the centering studs (22) on the clamping head (1). Apparatus according to claim 5, characterized in that the other positioning means further comprise the piano machined surface areas of this shoulder (29), which are designated for loading to the raised flat areas (23) on the upper tine of the clamping head (1). Device according to claim 1, characterized in that the lines of action of the clamping forces of the clamping bodies (18, 28) lie outside the imaginary, parallel to the Z-axis, first (22, 23) and second (29, 30) the positioning means of the intersecting sheath (M?) Of the cylinder. Apparatus according to claim 1 or 7, in a substantially cylindrical clamping head (1) and essentially as a hollow cylinder designed workpiece carrier (25), characterized in that the clamping body: (18, -1616 28) comprise distributed spherical coupling balls (18) distributed around the circumference of the clamping head (1), which are defined for engagement with the arranged annular groove (28) in the inner surface of the workpiece carrier (25). Apparatus according to claims 1 and 8, characterized in that the coupling device comprises a spring-loaded annular piston (12) which is arranged axially movably in the annular space (11) of the clamping head (1) and to which the coupling balls (18) are supported. and which is provided for pushing the coupling balls (18) radially into the closed annular groove (28) of the workpiece carrier (25). Apparatus according to claim 9, characterized in that the annular piston (12) is at one working position, where it is influenced by the spring (14) and the coupling ball (18) in a closed annular groove (28) of the carrier (28). 25) Workpiece, pneumatically or hydraulically adjustable to the standstill where the coupling balls (18) are unburdened. Apparatus according to claim 10, characterized in that the annular piston (12) has a closed annular groove (15) so arranged that the coupling balls (18) are inserted into the closed annular groove (15) when the annular piston (12) at rest. Apparatus according to one of Claims 8 to 11, characterized in that the clamping balls (18) are inserted into the radial holes (19), evenly spaced, along the clamping head (1). Apparatus according to one of claims 8 to 12, characterized in that twelve coupling balls (18) are provided. Apparatus according to one of claims 8 to 13, characterized in that the closed annular groove (28) of the workpiece carrier (25) has a substantially V-section. -1717 Apparatus according to one of Claims 8 to 14, characterized in that the axial position of the closed annular groove (28) in the workpiece carrier (25) is such that the clamping balls (18) of the clamping head (1) can be immersed in the annular groove (28) when the workpiece carrier (25) is freely inserted into the clamping head (1), with the plane (SS) of symmetry of the annular groove (28) being slightly above the center in the holes (19) of the clamping head (1) bullets (18;. Apparatus according to one of the preceding claims, characterized in that the clamping head (1) is substantially cylindrical, and the workpiece carrier (25) has a substantially one-sided shape with a circular ring of a closed hollow cylinder such that in the engaged state of the device the support ( 25) the workpiece encloses the clamping head (1). Device according to one of the preceding claims, characterized in that the two, the clamping head (1) and the workpiece carrier (25) have a central hole (5, 6, 8) for receiving the long-pointed workpieces.