Sliver delivery and opening device

Abstract

A sliver delivery and opening device having a pivotably seated sliver intake cylinder driven by a worm gear arrangement comprising a worm wheel connected to the sliver intake cylinder that meshes with a worm affixed to a drive shaft. The worm includes thread windings conforming to a superimposed profile that axially offsets the worm relative to the worm wheel, thus preventing placement of a tooth of the worm wheel on a thread head of the worm when the worm wheel pivotally engages the worm. The amount of offset is measured between a plane of symmetry intersecting the superimposed profile of the worm thread windings and a pivot plane intersecting a center axis of the worm wheel. A positioning device, comprising at least one magnet and a ferromagnetic positioning element, prepositions the worm wheel relative to the pivot plane for pivotal engagement of the worm wheel and the worm.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims the benefit of German Patent Application No. 10222291.6, filed May 18, 2002, hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a sliver delivery and opening device for an open-end spinning machine having a sliver intake cylinder selectively operable by a worm gear arrangement.

[0003] Sliver delivery and opening devices for open-end spinning machines are part of the prior art. During spinning operations, the open-end spinning devices are closed by a pivotably seated cover element that has attached to it the sliver delivery and opening device. These cover elements generally have a bearing bracket for a sliver opening roller and a bearing bracket for a sliver intake cylinder. A worm wheel, which along with a worm constitutes the worm gear arrangement, is affixed to an end of a rotatable shaft supporting the sliver intake cylinder and selectively engages the worm by means of an electromagnetic coupling that is also disposed on the shaft of the sliver intake cylinder. With the open-end spinning device closed, the worm wheel meshes with the worm, which is fixed on a drive shaft of the rotor spinning machine that extends over the length of the machine and is continuously rotating. When the open-end spinning device is open, the worm wheel and the worm are spaced apart, thus disengaging the worm wheel from the worm.

[0004] The above disclosed driving of a sliver intake cylinder has been successful, in principle, in actual use. However, difficulties can occasionally arise in the course of repositioning the worm wheel in the worm during engagement of the worm wheel with the worm. Such difficulties are evidenced by an increased wear of the worm wheel.

[0005] Overcoming such difficulties has been attempted. For example, in an open-end spinning device, described in German Patent Publication DE-AS 23 14 229, a pivot housing having a sliver intake cylinder and a sliver opening roller attached thereto, is seated on a separate pivot shaft spatially separated from the drive shaft extending over the length of the machine. The sliver intake cylinder, whose axis of rotation is parallel to the center axis of the drive shaft extending over the length of the machine, is connected to the drive shaft extending over the length of the machine by a special intermediate shaft that has a gear wheel on each of its ends. Upon opening the open-end spinning device, one of the gear wheels of the intermediate shaft slides out of a corresponding gear wheel fixedly installed on the drive shaft extending over the length of the machine. In order to minimize meshing and friction resistance occurring between the gear wheels when the open-end spinning device is closed, the pivot shaft, the drive shaft extending over the length of the machine, and the intermediate shaft are arranged such that while closing the open-end spinning device, an approximately tangential sliding of the gear wheel on the intermediate shaft onto the gear wheel of the drive shaft extending over the length of the machine takes place.

[0006] However, the above disclosed open-end spinning device, which is relatively complicated in its structure, has not proven itself in actual use and, hence, has not gained acceptance in the textile industry.

[0007] An open-end spinning device, having a pivotably seated cover element into which a sliver intake cylinder and a sliver opening roller are integrated and whose pivot shaft is arranged spaced apart from a drive shaft extending over the length of the machine, is also described in European Patent Publication EP 0 672 767 A1. With this known open-end spinning device, the sliver intake cylinder is driven by a worm wheel meshing with a worm that is fixed in place on a constantly rotating drive shaft extending over the length of the machine. With the open-end spinning device closed, the worm wheel of the sliver intake cylinder engages the corresponding worm, and with the open-end spinning device opened the worm wheel is spaced apart from the worm. In order to assure the correct operation of the sliver intake cylinder, the worm wheel and the worm commonly have the same pitch. In particular, the pitch of the worm wheel at the reference diameter relevant for the drive corresponds exactly to the pitch of the worm thread windings.

[0008] However, the disclosed arrangement results in the pitch of the worm wheel at the tip diameter being greater than the pitch of the worm thread so that, when the worm wheel is pivoted into and engages the worm, it is possible for two teeth of the worm wheel to simultaneously extend over two thread windings of the worm, thus preventing any further pivoting engagement of the worm wheel with the worm.

[0009] To overcome this disadvantage, and to ease the pivotal engagement of the worm wheel into the worm when the open-end spinning device is closed, it is provided in accordance with European Patent Publication EP 0 672 767 A1 to equip the worm thread windings with a special threading contour and to arrange the worm on the drive shaft such that a plane of symmetry of the worm—established by the threading contour—exactly corresponds to the pivot plane of the center axis of the worm wheel. In particular, the worm thread is given a superimposed profile, whose pitch exactly corresponds to the pitch of the worm wheel at the tip circle and which is laid out and arranged in such a way that the thread windings of the worm always end in a tip. The disclosed configuration assures that one of the teeth of the worm wheel enmeshes between two thread windings of the worm when the worm wheel pivotally engages and meshes with the worm.

[0010] However, actual use has shown that, although the correct enmeshing of the worm wheel into the worm is assured by worm gear arrangements designed and arranged in the disclosed configuration, such worm gear arrangements no longer have an optimal bearing behavior because of the reduction of the effective contact surfaces in the area of the thread windings of the worm. In particular, the worm wheel of such designed configured worm gear arrangements no longer rotates uniformly. Furthermore, the individual teeth of the worm wheel are subjected to more stresses than with conventional worm gear arrangements. The uneven rotation of the worm wheel leads to fluctuations in the sliver intake, while the great stress on the worm wheel teeth leads to increased wear of the worm wheel.

SUMMARY OF THE INVENTION

[0011] The present invention addresses the above discussed disadvantages by providing a sliver intake cylinder that is selectively operable by a worm gear arrangement in which a plane of symmetry intersecting a superimposed profile of the worm thread windings is axially offset from a pivot plane intersecting the center axis of the worm wheel, and a positioning device that positions the worm wheel as a function of the amount of offset of the plane of symmetry relative to the pivot plane prior to pivotal engagement of the worm.

[0012] The present invention has the particular advantage of providing a uniform rotation of the sliver intake cylinder and increasing the service life of the worm wheel while assuring that the worm wheel pivotally engages and meshes with the rotating worm during the closing of the open-end spinning device. Notably, the present invention improves the bearing behavior of the worm gear arrangement by means of the axial offset of the worm provided with a superimposed profile on its drive shaft, i.e. by displacing the worm orthogonally in relation to the pivot plane of the worm wheel, which has a positive effect on the rotation of the sliver intake cylinder, as well as on the service life of the worm wheel.

[0013] To assure the correct pivotal engagement of the worm wheel into the offset worm, a positioning device is provided to consistently preposition the worm wheel relative to the worm such that two teeth of the worm wheel are prevented from simultaneously covering two adjacent thread windings of the worm.

[0014] In a preferred embodiment, the positioning device locates the centerline of one of the teeth of the worm wheel at a preset positioning angle relative to the pivot plane of the center axis of the worm wheel. In particular, the positioning angle is a function of the amount of the offset of the worm and is calculated such that the worm wheel pivotally engages the worm in a consistent manner.

[0015] The angularly correct alignment of the teeth of the worm gear arrangement assures that no seizing or similar interference between the worm wheel and the worm occur when the worm wheel pivotally engages the worm. In particular, as already explained above, the propositioning dependably prevents two teeth of the worm wheel from being simultaneously placed over two adjoining thread windings of the worm.

[0016] In a preferred embodiment, the positioning device comprises at least one magnet that is affixed on the bearing housing of the electromagnetic coupling, and a ferromagnetic positioning element that is connected, and fixed against relative rotation thereof, to the worm wheel of the worm gear arrangement; the positioning element being decoupled from, and freely rotatable relative thereto, the sliver intake cylinder when the open-end spinning device is opened. Preferably, the at least one magnet of the positioning device comprises at least one permanent magnet. Such a permanent magnet does not require any additional energy supply, while providing the correct dependable alignment of the positioning element, and therefore a dependable setting of the angular position of the teeth of the worm wheel.

[0017] In a preferred embodiment, the positioning element of the present invention comprises a positioning disk having a plurality of radially protruding positioning shoulders, each of which is acted upon by the magnetic force of the at least one magnet of the positioning device. Thus, when the worm wheel pivotally engages the worm, the positioning shoulders cooperating with the at least one magnet consistently provides a preset, angularly correct alignment of the teeth of the worm wheel. The number of centering shoulders of the positioning disk preferably corresponds to the number of teeth of the worm wheel. Such correspondence ensures that one of the positioning shoulders is constantly located within the effective range of the magnet and is pivoted by it into the desired position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further features, embodiments, and advantages of the present invention will become apparent from the following detailed description with reference to the drawings, wherein:

[0019] FIG. 1 is a schematic of an open-end spinning device with a pivotably seated cover element having an integral sliver delivery and opening device in a closed, operating configuration;

[0020] FIG. 2 is a schematic of an open-end spinning device similar to that of FIG. 1, the open-end spinning device in an opened, non-operating configuration;

[0021] FIG. 3 is a partial cutaway view of the worm gear arrangement operating the sliver intake cylinder, illustrating the positioning device of the present invention that provides an angularly correct alignment of the teeth of the worm wheel, the worm wheel being spaced apart and disengaged from the worm; and

[0022] FIG. 4 is an elevational view of the worm gear arrangement similar to that of FIG. 3, illustrating the worm gear arrangement in a operating configuration, the worm wheel being in pivotal engagement with the worm.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0023] Referring now to FIGS. 1 and 2, an open-end spinning device 1 in a rotor spinning machine comprises a spinning box housing 2 fixed in place on a base frame of the rotor spinning machine (not shown in detail), by fastening means 3. Typically, a bracket 4 fastened on the spinning box housing 2 supports a support ring bearing 5, an axial bearing 6, and a rotor housing 7. The rotor housing 7 is connected via a pneumatic line 8 to a vacuum source 9 for establishing a vacuum within the rotor housing 7.

[0024] A spinning rotor 10 located inside the rotor housing 7 rotates at high speed during the operation of spinning. Spinning rotor 10 is supported by rotor shaft 11 seated in wedge gaps of the support ring bearing 5. The spinning rotor 10 is typically driven by a tangential belt 12 applied to the rotor shaft 11 by a tension pulley 13.

[0025] The rotor housing 7 is open toward a front of the open-end spinning device 1. During operation, the rotor housing 7 is closed by a fiber conduit plate 15 attached to a cover element 14. When covering the rotor housing 7, the cover element 14 rests against the front of the rotor housing 7. The cover element 14 rotates about a pivot shaft 19 to move away from the open end of the rotor housing 7, thus opening the rotor housing 7. The fiber conduit plate 15 preferably has an exchangeable fiber conduit plate adapter 16, attached thereto. A yarn withdrawal nozzle 17 and a mouth of a fiber guide conduit 18, are arranged in the fiber conduit plate adapter 16.

[0026] The open-end spinning device 1 also includes a sliver delivery and opening device 20 integral to the cover element 14. The sliver delivery and opening device 20 comprises a sliver intake cylinder 21 and a sliver opening roller 26. The sliver intake cylinder 21 is connected via a worm gear arrangement, comprising a worm wheel 22 and a worm 23, with a constantly rotating drive shaft 24 extending over the length of the machine. In particular, the worm wheel 22 is fastened at an end of shaft 36 of the sliver intake cylinder 21 and meshes with the worm 23 attached to the rotatable drive shaft 24. A magnetic coupling 25 connected to the shaft 36 selectively separates the worm wheel 22 from the sliver intake cylinder 21 when required. As shown in FIGS. 1 and 2, the sliver opening roller 26 is driven by a continuously rotating tangential belt 28 applied to a driving wharve 27 that is affixed to a back of the sliver opening roller 26.

[0027] FIG. 1 shows the open-end spinning device 1 during the spinning operation wherein the rotor housing 7 is closed by the cover element 14. In this operating state, the worm wheel 22 of the sliver intake cylinder 21 is enmeshed with the worm 23 which is connected with the rotating drive shaft 24, and the driving wharve 27 of the sliver opening roller 26 rests against the rotating tangential belt 28.

[0028] FIG. 2 shows the corresponding open-end spinning device 1 when not in operation. As illustrated in FIG. 2, the cover element 14 of the open-end spinning device 1 is pivoted around the pivot shaft 19 in the direction of the arrow A, thus opening the rotor housing 7. With the rotor housing 7 opened in this manner, the rotor housing 7 is easily accessible, for example for cleaning the spinning rotor 10.

[0029] When the cover element 14 is pivoted away from the rotor housing 7, the driving wharve 27 of the sliver opening roller 26 is lifted off the tangential belt 28, and the worm wheel 22 of the sliver intake cylinder 21 is disengaged and spaced apart from the worm 23 on the fixedly arranged drive shaft 24. A path followed by the worm wheel 22 during the opening of the open-end spinning device 1 is shown by dashed line S in FIG. 2.

[0030] The worm gear arrangement, i.e., the worm wheel 22 and the worm 23, is illustrated in FIGS. 3 and 4. In particular, FIG. 3 shows the worm wheel 22 slightly spaced apart from the worm 23, which would be the configuration just before the worm wheel 22 pivotally engages and meshes with the worm 23 as the rotor housing 7 is being closed by the cover element 14. FIG. 4 shows the worm wheel 22 fully enmeshed with the worm 23, which would be the configuration during spinning operations.

[0031] As shown in FIGS. 3 and 4, the worm wheel 22 is affixed to an end of the shaft 36 of the sliver intake cylinder 21. The worm wheel 22 comprises a plurality of teeth 32 at spaced intervals along a circumference of the worm wheel 22, the plurality of the teeth 32 projecting outwardly from a center axis 44 of the worm wheel 22. A reference circle 39 provides a pitch t and a tooth tip circle 38 provides a pitch T for the plurality of teeth 32 of the worm wheel 22. A pivot plane 43 perpendicular to the rotating drive shaft 24 upon which the worm 23 is affixed intersects the center axis 44 of the worm wheel 22.

[0032] The worm 23 is affixed on the rotating drive shaft 24 that extends over the length of the machine. The worm has thread windings 41 that have a trapezoidal cross-section with pitch t. A profile 40 is superimposed over a contour of the thread windings, 41, the superimposed profile 40 having a defined shape with a plurality of alternating peaks and valleys. The superimposed profile 40 has a pitch T corresponding to the pitch T measured at the tooth tip circle 38 of the worm wheel 22. The superimposed profile 40 is laid over the thread windings 41 such that each of the thread windings 41 terminates in a clearance lip. A plane of symmetry 42 perpendicular to the rotating drive shaft 24 intersects one valley of the alternating peaks and valleys of the superimposed profile 40 that is centered between two adjacent thread windings 41.

[0033] In the present invention, as shown in FIG. 3, as the worm wheel 22 is pivoted toward engagement of the worm 23, a centerline 33 of one tooth of the plurality of teeth 32 of the worm wheel 22 is constantly held at a positioning angle &phgr; relative to the pivot plane of the worm wheel 22. The positioning angle &phgr; is a function of an amount of offset X of the worm 23 wherein the amount of offset X is the distance between the plane of symmetry 42 of the worm 23 and the pivot plane 43 of the worm wheel 22, as shown in FIG. 3. Preferably, the positioning angle &phgr; is calculated by the equation:

&phgr;=72* sin(X/2)

[0034] To maintain the centerline 33 of the one tooth at positioning angle p during pivotal engagement of the worm wheel 22 with the worm 23, the present invention employs a positioning device 30. The positioning device 30 comprising a magnet 37, preferably a permanent magnet, that is affixed, for example, on a bearing housing 31 of the electromagnetic coupling 25, and ferromagnetic positioning element 34 that is connected to the worm wheel 22 such that the positioning element 34 is fixed against rotation relative to the worm wheel 22.

[0035] In a preferred embodiment, the positioning element 34 is a disk having radially protruding positioning shoulders 35 thereon. The magnet 37 is situated relative to the positioning shoulders 35 such that the magnet 37 acts upon the positioning shoulders 35 to maintain the plurality of teeth 32 of the worm wheel 22 at a desired position relative to the worm 23. In particular, the positioning device 30 maintains the centerline 33 of one tooth of the plurality of teeth 32 of the worm wheel 22 at the positioning angle &phgr;, as shown in FIG. 3.

[0036] The worm gear arrangement of the present invention, having the worm 23 axially offset relative to the worm wheel 22 by the amount of offset X, exhibits uniform rotation of the worm wheel 22 upon the worm 23, resulting in an even operation of the sliver intake cylinder 21 and subsequently a smooth sliver intake. Further, use of the positioning device 30 to position the worm wheel 22 relative to the worm 23 during pivotal engagement of the worm wheel 22 prevents two teeth of the plurality of teeth 32 of the worm wheel 22 from simultaneously extending over two adjacent thread windings 41 of the worm 23. This precludes any resultant interference with closing the rotor housing 7 of the open-end spinning device 1 and minimizes wear of the worm wheel 22.

[0037] It will therefore be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the foregoing description thereof, without departing from the substance or scope of the present invention. Accordingly, while the present invention has been described herein in detail in relation to its preferred embodiment, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for purposes of providing a fill and enabling disclosure of the invention. The foregoing disclosure is not intended or to be construed to limit the present invention or otherwise to exclude any such other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof.

Claims

1. A sliver delivery and opening device for an open-end spinning machine, the sliver deliver and opening device comprising:

a pivotable sliver intake cylinder;

a worm gear arrangement having a worm wheel connected to the sliver intake cylinder and a worm mountable on a fixedly supported rotatable shaft extending along the machine, the worm wheel having a plurality of teeth and the worm having thread windings with a threading contour conforming to a superimposed profile for preventing placement of a tooth of the worm wheel on a thread head of the worm, the worm being fixable on the rotatable shaft to present a plane of symmetry that is offset in an axial direction of the rotatable shaft with respect to a pivot plane of a center axis of the worm wheel, is perpendicular relative to the rotatable shaft, and intersects a valley of the superimposed profile centered between two adjacent threads of the worm; and

a positioning device for prepositioning the worm wheel as a function of the offset of, the worm to facilitate the pivoting of the teeth of the worm wheel into the worm.

2. A sliver delivery and opening device according to claim 1, characterized in that one tooth of the plurality of teeth of the worm wheel is positioned such that the centerline of the one tooth lies at a predetermined positioning angle &phgr; relative to the pivot plane of the worm wheel, wherein the positioning angle &phgr; is a function of the offset of the worm measured between the plane of symmetry and the pivot plane.

3. A sliver delivery and opening device according to claim 2, wherein the positioning angle &phgr; is calculated by an equation: &phgr;=72* sin(X/2), where X is the offset of the worm.

4. A sliver delivery and opening device according to claim 1, characterized in that the positioning device comprises at least one magnet fixed in place on a bearing housing of an electromagnetic coupling attached to a shaft of the sliver intake cylinder, and a ferromagnetic positioning element that is connected, and fixed against relative rotation, to the worm wheel.

5. A sliver delivery and opening device according to claim 4, wherein the at least one magnet of the positioning device comprises at least one permanent magnet.

6. A sliver delivery and opening device according to claim 4, wherein the positioning element comprises a positioning disk having a number of radially protruding ferromagnetic positioning shoulders disposed thereon.

7. A sliver delivery and opening device according to claim 6, wherein the number of ferromagnetic positioning shoulders corresponds to a total number of teeth that comprise the plurality of teeth of the worm wheel.