Abstract
A positioning device for positioning a tool holder (12, 14, 16, 18) on a tool turret (6) of a machine tool by means of positioning pins (10), which are secured to the tool turret (6) and which engage with receptacles (40) on the tool holder (6) when the tool holder (12, 14, 16, 18) is attached to the tool turret (6), is characterized in that at least one of the receptacles of the tool holder (6) is formed by a sleeve (40), with which the assignable positioning pin (10) engages in the mounted state while contacting the inner circumferential surface (58) of the sleeve (40), and in that the inner circumferential surface (58) is part of an expanding part (56), which, when the pin (10) engages, expands elastically and flexibly away from the pin (10).
Claims
1. A positioning device for positioning a tool holder (12, 14, 16, 18) on a tool turret (6) of a machine tool by means of positioning pins (10), which are secured to the tool turret (6) and which engage with receptacles (40) on the tool holder (6) when the tool holder (12, 14, 16, 18) is attached to the tool turret (6), characterized in that at least one of the receptacles of the tool holder (6) is formed by a sleeve (40), with which the assignable positioning pin (10) engages in the mounted state while contacting the inner circumferential surface (58) of the sleeve (40), and in that the inner circumferential surface (58) is part of an expanding part (56), which, when the pin (10) engages, expands elastically and flexibly away from the pin (10).
2. The positioning device according to claim 1, characterized in that the pin (10), to the extent that it protrudes from the turret (6), has an outer circumferential surface (36), which is at least partially different from the inner circumferential surface (58) of the sleeve (40) in such a way that in the mounted state only partial contact, preferably in the manner of a line contact, is established between the surfaces (36, 58).
3. The positioning device according to claim 1, characterized in that the outer circumferential surface (36) of the pin (10) is at least partially convex or conical and the inner circumferential surface (58) of the sleeve (40) is conical or concave at least in the area of contact.
4. The positioning device according to claim 1, characterized in that in the installed state the inner circumference of the sleeve (40) expands conically towards the surroundings and in that the expanding part (56) of the sleeve (40) is encompassed on the outer circumference by a recess (66) in the holder (12, 14, 16, 18) through which the sleeve (40) passes while maintaining a radial gap.
5. The positioning device according to claim 1, characterized in that both the pin (10) and the sleeve (40) is fixed in the turret (6) or in the holder (12, 14, 16, 18) by one screw connection (24, 42) each, have a continuous hollow duct (22, 44), in which a point of action (38, 46) for an operating tool is located, and rest against the turret (6) or the holder (12, 14, 16, 18) via an annular support part (30, 50) outside the screw connection (24, 42).
6. The positioning device according to claim 1, characterized in that in the holder (12, 14, 16, 18), having a rectangular cross-section, has at each of its corner areas (70) one sleeve (40), to which four pins (10) are assigned on the turret (6) at a preferably standardized interface, and in that the holder (12, 14, 16) and the interface provide a reach-through (74) for the passage of a drive shaft (78) of a drivable machining tool, which can be secured at the turret (6) by means of the holder (12, 14, 16).
7. The positioning device according to claim 1, characterized in that the holder (12, 14, 16, 18) remains still on the turret (6) by means of a detachable fixing device (82) even if a coupling device in the turret (6) has released the holder (12, 14, 16, 18) for a tool change operation.
8. The positioning device according to claim 1, characterized in that the fixing device for a holder (12, 14, 16, 18) has at least one bending rod (82), one free fixing end of which is secured to the holder (12, 14, 16, 18) and, in the mounted state, the other free latching end (86, 92) of which extends under a projection (80) in the hollow duct (22) of the pin (10), and in that the latching end (86, 92) of the bending rod (82), which passes through both cavities (22, 44) and is actuated by means of an actuating device (88), comes out of engagement with the projection (80) of the pin (10) and the holder (12, 14, 16, 18), released from the turret (6), can be removed.
9. The positioning device according to claim 1, characterized in that the actuating device has an actuating pin (88), which is supported in the holder (12, 14, 16, 18) transversely displaceable to the bending rod (82), in that one end of the actuating pin (88) acts on the bending rod (82) and from the other end (94), which is accessible from the outside of the holder, the actuating pin (88) can be set into a shift motion, which brings the latching end (86, 92) of the bending rod (82) into the releasing position.
Description
[0015] Below the invention is explained in detail with reference to exemplary embodiments shown in the drawing. In the Figures:
[0016] FIG. 1 shows a perspective oblique view of a tool turret equipped with an exemplary embodiment of the positioning device according to the invention, viewed towards the tool disk;
[0017] FIG. 2 shows a magnified perspective oblique view of a sleeve of the exemplary embodiment, viewed on the top;
[0018] FIG. 3 shows a perspective oblique view of a positioning pin of the exemplary embodiment, drawn at the scale of FIG. 2 and viewed from the top;
[0019] FIG. 4 shows a perspective oblique view of the sleeve of FIG. 2, drawn to the same scale and viewed from below;
[0020] FIG. 5 shows a perspective oblique view of the positioning pin of FIG. 3, drawn to the same scale and viewed from below;
[0021] FIG. 6 shows a partial subsection, sectioned in a radial plane, of a circumferential section of the tool disk of FIG. 1, wherein of two adjacent working stations one positioning pin each of the exemplary embodiment of the positioning device is shown, and wherein on the left side an assigned subsection of a tool holder prior to attachment is shown and on the right side such a section in the inserted position is shown;
[0022] FIG. 7 shows a cross-section of the foot part of a tool holder to be aligned by the positioning device according to the invention; and
[0023] FIG. 8 shows a partial section, sectioned in a radial plane, of a circumferential section of the tool disk and a part of a tool holder aligned thereto by a second exemplary embodiment of the positioning device according to the invention, provided with a fixing device.
[0024] The tool turret 2 shown in FIG. 1 has on a base body 4 a tool disk 6 supported pivotable about a turret axis, wherein said tool disk, in the manner customary for such turrets, has on its outer circumference work stations, in the example shown in the FIG. 12 work stations. For fixing tool holders, a mounting surface 8 (only partially numbered in FIG. 1) is formed at every work station, wherein at said mounting surfaces 8 tool holders via an assigned foot part 14 can be fixed in an aligned position by means of positioning pins 10. In the illustration of FIG. 1 only part of the work stations is equipped with tool holders. Apart from a tool holder 12, which is designed for a driven tool having straight drive axis, FIG. 1 shows tool holders 16 for driven tools having an angle drive, a tool holder 18 for a static tool, such as a lathe tool, and a cover 20, which is formed by a foot part 14 without the assigned tool holder part. As a protective element at an empty work station, the cover 20 can, in a positional orientation predetermined by means of the positioning device according to the invention, be attached to or released from the concerning mounting surface 8 of the tool turret in the same way as the foot parts 14 of the tool holders 12, 16, 18, wherein the fixing device can be actuated by the tool drive of the tool disk 6 in a system-controlled manner, as shown in the patent application DE 10 2018 004 677.0, which discloses a post-published state of the art.
[0025] The positioning pins 10 are one-piece rotational bodies having an interior, coaxially continuous hollow duct 22. At their mounting end, the positioning pins 10 have a threaded section 24, which can be used to screw them to a female thread 26 in a drilled receiving hole 28 in the mounting surface 8 of the assigned work station of the tool disk 6. At the end of the threaded section 24, the length of which is approximately one third of the total length of the positioning pin 10, the outer diameter of the threaded pin 10 merges at a step 30 into a circular cylindrical part 32 having an enlarged diameter, for which in the drilled receiving hole 28 between the female thread 26 and the end of the drilled hole a drilled hole section 34 forms a snug fit. In the screwed-in position, wherein the step 30 contacts the shoulder formed between the cylindrical part 32 and the female thread 26 (FIG. 6), the positioning pin 10 protrudes by approximately half of its total length beyond the mounting surface 8. The part, protruding from the mounting surface 8, of the positioning pin 10 is ground crowned and having a slightly convex curved shape on its outer circumferential surface 36. The positioning pin 10 is completed by an internal hexagon socket 38, formed at the mounting end in the hollow duct 22 within the threaded section 24, as a point of action for a tool, which can be used to form the screw connection.
[0026] As an alignment part, assigned to the foot part 14 of the tool holders 12, 16, 18 or the cover 20, a sleeve 40 is provided which, like the positioning pins 10, is formed by a one-piece rotary body which, as a screw-in part, has an male threaded section 42 which, starting from the end of the male threaded section 42, extends along approximately one quarter of the total length of the sleeve 40 and can be screwed together with an female thread 68 in a drilled receiving hole 66 of the foot part 14 concerned. Like the positioning pins 10, the sleeve 40 has an inner, continuous, coaxial hollow duct 44, see FIG. 6, in the end part, located within the threaded section 42, of which there is a hexagon socket 46 for an actuating tool, which can be applied to form the screw connection. At a shoulder 48, the outer diameter of the sleeve 40 is enlarged by a collar 50 having an outer circumference forming a mating surface 52. Adjoining to the collar 50, and offset radially inwards via a further shoulder 54, the sleeve 40 having an expanding part 56 extends towards the end. The axial length of the expanding part 56 is slightly smaller than half of the total length of the sleeve 40. The wall thickness of the sleeve 40 in the area of its expanding part 56 is about half of the wall thickness of the collar 50, so that the expanding part 56 can be expanded by radial forces acting thereon. As can be seen most clearly from FIG. 6, in which not all elements are numbered in the part of the drawing on the right, the wall of the expanding part 56 starts from a point at the shoulder 54, which is radially inwardly offset in relation to the collar 50, from where the wall of the expanding part 56 diverges towards the end, and wherein the inner peripheral surface 58 forms a cone expanding the hollow duct 44 like a funnel towards the end, through which the assigned fitting pin 10 can be inserted. Between the cone and the end provided with the hexagon sleeve 46, the inner diameter of the hollow duct decreases in two stages having cylindrical drilled hole sections 60 and 62. On the outside, the expanding part 56 has a cylindrical end part 64 at the end of the outer cone. If the sleeve 40 is screwed into the foot part 14, as shown in FIG. 6, the end part 64 is located at a radial gap from the encompassing wall of the drilled receiving hole 66 formed in the foot part 14 for the sleeve 40.
[0027] FIG. 6 shows, in the part of the figure on the right, a subsection of a work station and the part of a tool holder 12, foot part 14 of which is placed on the mounting surface 80 and is aligned by means of the positioning device according to the invention. One single of the positioning pins 10, assigned to the work station, is shown in the partial representation of the figure in the positioning position retracted into the expanding part 56 of the assigned sleeve 40. The left part of the figure in FIG. 6 shows the position of the foot part 14 before it is attached to the tool disk 6 for the lifting out process using the assigned positioning pin 10. As shown, at the end of the circumferential surface 36, running crowned and having a convex curved shape, the outer diameter of the positioning pin 10 is smaller than the diameter of the opening of the expanding part 56, which widens with a conical inner circumferential surface 58. The entry funnel formed in this way therefore enables reliable entry of the positioning pin 10 into the expanding part 56 even in case of positional tolerances, because the surface contact only occurs within the expanding part 56. Possible positional tolerances are eliminated during the retraction process by the surface contact between the circumferential surface 36 of the pin 10 and the inner circumferential surface 58 of the expanding part 56, so that the precisely fitting alignment is achieved. Because the expanding part 56 can be elastically expanded and because the outer wall of the expanding part 56, starting from the starting point, radially inwardly offset at the shoulder 54, up to the end part 64, is at a radial gap from the encompassing wall of the drilled receiving hole 66, free space is available for deformation. Without impairing the accurate positioning, such a certain amount of flexibility avoids the problems known to occur in the presence of several mating points because of static overdetermination. It is therefore advantageous to provide at the work stations of the tool disk four positioning pins 10, which interact with sleeves 40, which are arranged in corner areas of the concerning rectangular foot part 14, as shown in FIG. 7. Due to the different shapes of the surfaces, interacting in the retracted position, in the example shown of the conical inner circumferential surface 58 of sleeve 40 and the convexly crowned circumferential surface 36 of pin 10, the contact surfaces in the insertion position are not in consistently full-surface contact, but the contact is rather similar to a line contact.
[0028] FIG. 7 shows the arrangement of one sleeve 40 each in each of the four corner areas 70 of the foot part 14, rectangular in outline, of a concerning tool holder, which is intended for a rotary driven tool. For the passage of the assigned spindle drive, the foot part 14 has a centrally located passage opening 74 for the shank 76 and the shaft 78 of the concerning spindle drive.
[0029] FIG. 8 shows a modified exemplary embodiment, in which the inner hollow duct 22 of the respective positioning pin 10 adjoining to the hexagon socket 38 does not form a smooth inner cylinder as in the first exemplary embodiment, but has a radially inwardly protruding latching projection 80. It forms the component of an additional fixing device, which secures a foot part 14, which is located on the tool disk 6 in the position aligned by means of the positioning device, on the tool disk 6 even if the turret-sided fixing device has released this foot part 14. This securing fixing device comprises a bending rod 82, one end area of which is attached to the foot part 14 via a bending point 84 and extends starting from the bending point 84 through both cavities 44 and 22 of an interacting pair of sleeve 40 and positioning pin 10. At its free end 86 the bending rod 82 has a latching hook 92, which secures the foot part 14 to the tool disk 6 by latching engagement on the projection 80 of the pin 10. In order to release the latching engagement, in the foot part 14 an actuating pin 88 is provided, which is supported displaceable transversely to the bending rod 82 in the foot part 14 and can be displaced against the force of a return spring 90 in such a way that its free end applies bending force to the bending rod 82 near the bending point 84 and in that way disengages the latching hook 92 from the projection 80, releasing the foot part 14 for removal. The end 94, facing away from the bending rod 82, of the actuating pin 88 is accessible from the outside of the foot part 14, such that the additional fixing device can be unlocked by a control part acting on the actuating pin 88 from the outside.
