Thread rolling head

Abstract

A thread rolling head includes a bearing housing, in which at least two profile rollers, preferably at least three, are each rotatably mounted on an eccentric shaft. A shank is coupled to the housing, and adjacent profile rollers delimit an insertion section into which a workpiece can be longitudinally inserted. The bearing housing includes two housing parts rotatable relative to each other to change the spacing between the profile rollers. An adjustment element interacts with one of the two housing parts and can rotate about the longitudinal axis thereof. Rotation of the adjustment element in a first direction causes rotation of the two housing parts in a third rotational direction, while its rotation in the second direction causes rotation of the housing parts in a fourth rotational direction counter to the third rotational direction. A display apparatus displays a change of the spacing between the profile rollers.

Claims

1. A thread rolling head, comprising: a bearing housing for at least two profile rollers, each rotatably mounted on a respective eccentric shaft; and a shank coupled to the bearing housing; wherein: adjacent rollers of the at least two profile rollers delimit an insertion section into which a workpiece to be machined can be inserted in a longitudinal direction defined by a rotational axis of the shank; the bearing housing comprises two housing parts that can rotate relative to each other; rotation of the two housing parts relative to each other changes spacing between the at least two profile rollers; an adjustment element interacts with one of the two housing parts and is rotatable in two directions of rotation about a longitudinal axis thereof, the two directions including a first direction of rotation and a second direction of rotation; a rotation of the adjustment element in the first direction of rotation causes relative rotation of the two housing parts to each other in a third direction of rotation; a rotation of the adjustment element in the second direction of rotation causes relative rotation of the two housing parts to each other in a fourth direction of rotation counter to the third direction of rotation; and a display apparatus displays a change of the spacing between the at least two profile rollers, and wherein the adjustment element is a threaded spindle rotatable about a longitudinal axis thereof and fixed in an axial direction relative to the longitudinal axis on one of the two housing parts.

2. The thread rolling head according to claim 1, further comprising: a gearing mechanism that changes the spacing between the at least two profile rollers with relative rotation of the two housing parts with respect to each other.

3. The thread rolling head according to claim 2, wherein: the gearing mechanism comprises a center gear fixed against rotation to the shank and at least two outer gears meshing with the center gear; and each eccentric shaft is fixed against rotation to respectively one outer gear of the at least two outer gears.

4. The thread rolling head according to claim 1, wherein: the bearing housing has a front plate; a first housing part of the two housing parts is an intermediate plate; and the at least two profile rollers, together with the eccentric shafts bearing them rotatably, are held between the front plate and the intermediate plate.

5. The thread rolling head according to claim 4, wherein a second housing part of the two housing parts is a spring housing in which at least one spring element is arranged.

6. The thread rolling head according to claim 5, wherein: a plurality of distance bolts is arranged between the front plate and the intermediate plate, each distance bolt fastened to the front plate and extending with an end section through the intermediate plate and the spring housing and each having a thread formed at the end section; and a respective lock nut is screwed onto each thread from a side of the spring housing facing away from the front plate.

7. The thread rolling head according to claim 6, further comprising: a slide block having a thread that engages with the threaded spindle such that, with rotation of the threaded spindle in the first direction of rotation or the second direction of rotation, the slide block moves axially forward or backward on the threaded spindle to thereby cause relative rotation of the two housing parts in the third direction of rotation or the fourth direction of rotation; and wherein: one distance bolt of the plurality of distance bolts is accommodated radially movable in a receiving opening of the slide block such that axial movement of the slide block causes arc- shaped movement of the one distance bolt guided in the receiving opening, and thereby rotates the intermediate plate relative to the spring housing or rotates the spring housing relative to the intermediate plate.

8. The thread rolling head according to claim 7, wherein the receiving opening of the slide block is one of: a recess open on one side; or an elongated hole, a longitudinal direction of which runs transverse to a direction of the axial movement of the slide block.

9. The thread rolling head according to claim 1, further comprising: a slide block having a thread that engages with the threaded spindle such that, with rotation of the threaded spindle in the first direction of rotation or the second direction of rotation, the slide block moves axially forward or backward on the threaded spindle to thereby cause relative rotation of the two housing parts in the third direction of rotation or the fourth direction of rotation.

10. The thread rolling head according to claim 9, wherein the threaded spindle is rotatable through an access opening in one of the two housing parts using a screwing tool.

11. The thread rolling head according to claim 1, wherein the display apparatus comprises a scale having scale marks arranged on one of the two housing parts and a display element interacting with the scale marks on the other of the two housing parts.

12. The thread rolling head according to claim 11, wherein the scale is non-uniformly divided such that with relative rotation of the two housing parts by any two adjacent scale marks there is a uniform change in spacing of the at least two profile rollers.

13. The thread rolling head according to claim 1, wherein the display apparatus displays a zero position of the at least two profile rollers in an assembled starting state of the two housing parts.

14. The thread rolling head according to claim 1, wherein: the one of the two housing parts is a first housing part, the two housing parts including a second housing part; the rotation of the adjustment element in the first direction of rotation causes relative rotation of the two housing parts to each other in the third direction of rotation by rotating the first housing part in the third direction while the second housing part is not rotated; and the rotation of the adjustment element in the second direction of rotation causes relative rotation of the two housing parts to each other in the fourth direction of rotation counter to the third direction of rotation by rotating the first housing part in the fourth direction while the second housing part is not rotated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views unless otherwise noted, and wherein:

(2) FIG. 1 is a perspective, exploded view of a thread rolling head according to an embodiment of the invention;

(3) FIG. 2 is a perspective view of a spring housing of the thread rolling head of FIG. 1;

(4) FIG. 3 is a further perspective view of the spring housing of FIG. 2;

(5) FIG. 4 is a perspective view of a spring housing of the thread rolling head of FIG. 1 used to explain alternative embodiments of the invention;

(6) FIG. 5 is an enlarged detail view of an adjustment element according to an embodiment of the invention;

(7) FIG. 6 is an enlarged detail view of an adjustment element according to another embodiment of the invention; and

(8) FIG. 7 is an enlarged detail view of an adjustment element according to yet another embodiment of the invention.

DETAILED DESCRIPTION

(9) FIG. 1 shows a thread rolling head according to an embodiment of the invention, here an axial thread rolling head. It has a bearing housing LG and a shank 1. The shank 1 can be mounted, for example, in a numerically-controlled tool machine. It has a coupling section 30 and a cylindrical bearing section 32. In addition, it has a splined section 34. In the example shown there are three profile rollers 18 in the bearing housing, each mounted on an eccentric shaft 5. The ends of the eccentric shafts 5 are seated in corresponding bore holes of a front plate 4 and an intermediate plate 3. The two plates 3, 4 are held separated by distance bolts 6. The distance bolts 6 are screwed to the front plate 4 using screws 14. A threaded opposing end section of the distance bolts 6 extends through corresponding bore holes in the intermediate plate 3.

(10) The profile rollers 18 are mounted rotatably on the eccentric shafts 5, which are flattened on the rear ends, wherein the flattened end in turn interacts with correspondingly designed boreholes of outer gears 8. The outer gears 8 part mesh with a center gear 7. The center gear 7 is mounted on the splined section 34 of the shank 1. When the center gear 7 rotates, the outer gears 8 and thus the eccentric shafts 5 rotate. Rotation of the eccentric shafts 5 leads to a change of the mutual spacing of the profile rollers 18. For thread forming, the profile rollers 18 require a preset spacing from each other in a machining position. This must be enlarged in an open position such that the machined workpiece can be withdrawn from between the rollers 18.

(11) A spring housing 36 sits with a center bore hole on the bearing section 32 of the shank 1. It has a dog clutch section (not shown in FIG. 1), which interacts with the coupling, or dog clutch, section 30 of the shank 1. A spiral spring 10 whose outer end interacts with a slit within the spring housing 36 is arranged in the spring housing 36. The inner end of the spiral spring 10 is connected to the bearing section 32 of the shank 1.

(12) A spring ring 11 secures the axial bearing of the bearing housing on the shank 1. The end sections of the distance bolts 6 extend through arc-shaped elongated holes of the spring housing 36 and through bore holes of a locking washer 16. The spring housing 36 is securely screwed against the intermediate plate 3 using lock nuts 15 screwed onto the threads of the end sections of the distance bolts 6, wherein the relative rotational position between spring housing 36 and intermediate plate 3 can be previously adjusted manually. A scale is provided on the spring housing 36 for this purpose.

(13) If the dog clutch sections are in engagement, the profile rollers 18 have a preset spacing to each other, namely in the machining position. The spiral spring 10 is tensioned. If a thread is formed in a workpiece that is inserted in the insertion section between adjacent profile rollers 18, the workpiece moves rotatingly into the thread rolling head, or respectively the bearing housing, until the feed motion of the shank 1 together with the bearing housing LG is terminated by a stop (not shown), and the bearing housing LG itself is moved further due to the described feed motion. As a result, the claws of the dog clutch are disengaged and the spring housing 36 and thus the bearing housing LG perform a rotation due to the spring action of the spiral spring 10. This latter rotation can occur only over a predefined angle of rotation due to the construction of the dog clutch. This relative rotation of shank 1 and bearing housing LG causes, as described, a rotation of the eccentric shafts 5 such that the profile rollers 18 move into the open position thereof and the thread rolling head is opened. The workpiece can then be removed from the thread rolling head.

(14) If the thread rolling head is to be closed again, the spring housing 36 must be rotated in the opposite direction via the shank 1 until the dog clutch engages again. Because the bearing housing, with the described opening movement, was axially removed from the shank 1, a tensile force was also exerted on the spiral spring 10. The dog clutch sections are brought into engagement again using this tensile force. With this, the profile rollers 18 are again located in the machining position. Thusly, the thread rolling head is closed for a new machining process.

(15) Exemplary embodiments of a precise adjustment of the spacing of the profile rollers 18 to each other in the machining position thereof are explained using FIGS. 2 to 7. Here, the spring housing 36 of the thread rolling head according to FIG. 1 is shown in particular in FIGS. 2 to 4. The gearing mechanism of center gear 7 and outer gears 8 may also be arranged between the intermediate plate 3 and the front plate 4.

(16) FIG. 2 shows one of the three distance bolts 6 of the thread rolling head as an example. A lateral access opening 38 of the spring housing 36 can be seen in FIGS. 2 and 3, through which a threaded spindle 40 can be rotated in a first or second direction of rotation. The threaded spindle 40 is rotatably mounted in an axially fixed position within the spring housing 36. A slide block 42 is arranged on the threaded spindle 40. A thread is formed on the slide block 42 that is in engagement with the thread of the threaded spindle 40 such that the slide block 42 is moved axially forward or backward with respect to the longitudinal direction of the threaded spindle 40 with rotation of the threaded spindle 40 in a first or second direction of rotation. The slide block 42 has an elongated hole 44 running in the radial direction in which the distance bolt 6 is guided radially movable. The other two distance bolts 6, which for reasons of clarity are not shown in FIGS. 2 and 3, are guided in the arc-shaped elongated holes 46 formed in the spring housing 36.

(17) In this arrangement, if the threaded spindle 40 is screwed in or out via the access opening 38, the slide block 42 moves axially forward or backward and the distance bolt 6 moves with it such that, in the course of its axial movement, the slide block 42 simultaneously moves radially in the elongated hole 44, and thus describes in total an arc-shaped movement, which corresponds to the arc-shape of the arc-shaped elongated holes 46 in the spring housing 36. In this way, the intermediate plate 3 can be rotated with respect to the spring housing 36 such that the spacing of the profile rollers 18 to each other is adjusted in a defined and precise manner using the gearing mechanism composed of the center gear 7 and outer gears 8.

(18) Here, on one side in the region of the access opening 38, a display 48 is provided that shows, using a + or sign, the screw direction for increasing or decreasing the spacing of the profile rollers 18. Furthermore, a display apparatus on the spring housing 36 can be seen in FIG. 3. In this example, the display apparatus comprises a scale 50 with non-uniform scale mark divisions. A corresponding numerical mark is provided on the intermediate plate 3 of the thread rolling head. The scale 50 is divided non-uniformly so that there is always the same spacing change of the profile rollers 18 between any two adjacent scale marks.

(19) Further embodiments of the invention are explained as examples using FIG. 4. Although three different embodiments are shown in the spring housing 36, actually in each case only one of the displacement possibilities is used, whereas at the other positions for example, the distance bolts 6 are guided in arc-shaped elongated holes 46. The embodiment shown in FIG. 4 on the top right side corresponds largely to that shown in FIGS. 2 and 3, with the difference that the slide block 42 in this case has no radial elongated hole for accommodating the distance bolt 6 but rather has a recess 52 that is open outward on one side in the radial direction. This is shown in an enlargement in FIG. 6. The function is identical to that of the embodiment explained in FIGS. 2 and 3.

(20) The bottom of FIG. 4 shows an embodiment that is shown enlarged in FIG. 7. In this case, a threaded pin 54 that can be screwed in or out via a lateral access opening 38 is guided axially movable in an internal thread of the spring housing 36. The threaded pin 54, on the end thereof facing away from the access opening 38, has a receiving opening 56. In this example, the receiving opening 56 is a recess opened outward in the radial direction. It could, however, be an elongated hole running in the radial direction. The distance bolt 6 with the end section thereof is in turn guided movable in the radial direction in the receiving opening 56. The function of this embodiment again corresponds largely to that of the embodiment shown in FIGS. 2 and 3, with the difference that in this case the threaded pin 54 itself moves in the axial direction, and via the receiving opening 56 thereof, causes the movement of the distance bolt 6 and thereby relative rotation between the spring housing 36 and the intermediate plate 3.

(21) FIG. 4 on the upper left side shows another embodiment that is shown in an enlarged detail in FIG. 5. In this case, an adjusting worm gear 60 is provided with external teeth 58 that in turn can be rotated in both directions of rotation through a lateral access opening (not shown in FIG. 4). The adjusting worm gear 60 is held in the spring housing 36 in a fixed position in the axial direction and interacts with teeth formed on the intermediate plate 3. Thereby, the rotation of the adjusting worm gear 60 in the first or second direction of rotation causes rotation of the intermediate plate 3 relative to the spring housing 36 in the first or second direction of rotation.