The object of the invention is a top arm for a spinning machine, wherein the spinning machine has a plurality of top rollers and bottom cylinders associated with a respective one of the top rollers and a support unit, the top arm comprises an arm body pivotally connected to the support unit, a locking unit between the support unit and the arm body to lock and release the arm body with respect to the support unit and separate loading units connected to the arm body to provide load on associated ones of the top rollers.

Such a top arm is disclosed in the publication EP 0 382 909 A2 wherein a sheet metal top arm design has been shown with respective leaf springs acting as loading units which provide appropriate load to the associated top rollers. Every leaf spring is fixed to its own spring holder and the spring holders are fixed to the internal surface of the top arm body by screws. Between the first spring holder and the internal surface of the top arm body a hook shape cleaning roller holder is situated and fixed by means of screws to the spring holder. On the top surface of the top arm, three elongated openings are prepared to receive the spring holder screws and make them possible to be adjusted in longitudinal direction. The adjustment is necessary because of the different situations of the bottom cylinders on different types of spinning machines. By adjusting the position of the spring holders together with their screws, the accurate positions of the top rollers can be set according to the position of the bottom cylinders. The top arm disclosed in this publication is sufficiently flexible and can be installed in case of different spinning machines. It is also possible to adjust the required position of the top roller holders. At the same time it is a necessary task to carry out the individual adjustments of the top arm in case of different spinning machines and there is a risk that the top arm will be misaligned by the operators or by the operation. The publication DE 10 2014 003 101 A1 discloses a top arm for drawing frames of spinning machines wherein no adjustment can be made at all, and this top arm comprises at least two pressure rollers with axes substantially parallel to one another The pressure rollers are arranged on the top arm in such a way that the distances between the axes of the pressure rollers are not adjustable, and the loads acting on the lower cylinders of the drafting devices by the pressure rollers during operation are also not adjustable.

While the non-adjustability has certain advantages, there are situations when certain adjustments or changes are required, especially if the extent of the required load for different top rollers is different, or if the direction of the load should be changed or if the distance between the top rollers should be different. Of course, for any predetermined machine such data are predetermined, but the tasks can change and the design of a different top arm for every occasion increases costs.

There must be an optimum tradeoff between fully adjustable top arms which can be used and adjusted for different machines, and the non adjustable solutions used in the second publication. The basic object of the present invention is to find an optimum ways between flexibility and predetermined designs, wherein the majority of the parts and components can be made in a uniform way, and in case certain adjustment or changes should be made, only a minimum number of parts should be replaced.

This and other objects have been resolved by providing a top arm for spinning machines as defined in the attached claims.

The invention will now be described in connection with preferable embodiments thereof in which reference will be mad to the accompanying drawings. In the drawing:

Fig. 1 is the elevation view of a first embodiment of the top arm;

Fig. 2 is a partially exploded elevation view of the first embodiment of the top arm; Fig. 2b is the cross sectional view of the top arm partially in an exploded view;

Fig. 2c is a cross sectional view of a loading unit taken along the plane B-B;

Fig. 2d is another cross sectional view of the loading unit taken along the plane C-C;

Fig. 3 is a partially exploded elevation view of a second embodiment of the top arm;

Fig. 3b is a cross sectional view of the loading unit 25c taken along the plane A-A of Fig. 3; Fig. 4 is a partially exploded elevation view of a third embodiment of the top arm; and

Fig. 4b is the back view of the loading unit 45c shown in Fig 4.

Fig. 1 shows the elevation view of a top arm 100 representing an embodiment of the present invention. The top arm 100 is pivotally connected to support rod 2 of the spinning machine served thereby by means of a support unit 1 of which in Fig. 1 only a small part is shown. Arm body 3 of the top arm 100 is connected to the support unit 1, and a locking unit 4 is provided in the arm body 3 which is operated by lever 20 and it is connected between the support unit 1 and the arm body 3 to lock and to release the arm body 3 with respect to the support unit 1. The lever 20 can be turned around shaft 21 to release and open and to load and lock the top arm 100. The arm body 3 can be turned around the support rod 2, which constitutes its pivotal axis. Loading units 5a, 5b, 5c are connected to the arm body 3 through a holding insert 6. The loading units 5a, 5b and 5c are loading respective top rollers 9a, 9b and 9c against respective oppositely positioned bottom cylinders 7a, 7b, 7c of the spinning machine. A separate cleaning roller 8 is shown and held at the hook-shaped front end of the holding insert 6. The top rollers 9a, 9b and 9c, the bottom cylinders 7a, 7b and 7c as well as the cleaning roller 8 are illustrated schematically by respective circles. The top arm 100 according to the invention is realized in a symmetric twin arrangement, and the other side (not shown in the drawing) is mirrored to the center plane of the twin arrangement.

Fig. 2 shows the top arm 100 in such a way that the three loading units 5a, 5b and 5c and holding insert 6 are shifted from their normal positions (forming thereby an exploded view) and

Fig. 2b is a sectional view taken along the plane A-A, and Figs. 2c and 2d show respective cross sections of the loading unit 5c taken along planes B-B and C-C.

The arm body 3 has a U-shape cross section with a distance K between its parallel and downwardly bent walls and the holding insert 6 has also a U-shaped profile with a width corresponding to the size K whereby the holding insert 6 fits into the interior of the U-shaped arm body 3 as can be seen in Fig. 2b. In an assembled position the upper surface 16 of the holding insert 6 is abutting interior upper surface 17 of the arm body 3, and there is only minimum tolerance gap between side surfaces 14 of the holding insert 6 and interior of the arm body 3, whereby the holding insert 6 can be fitted into the arm body 3 by pushing it in rearward direction from the front opening of the arm body 3 . The insertion of the holding insert 6 into the arm body

3 should be made in such a way that the front end of the arm body 3 has respective short projections 15 which can be made to engage respective laterally projecting abutting surfaces 14 on the very front part of the holding insert 6, and at the rear part of the holding insert 6 respective lateral protrusions 18 are provided and at corresponding locations the arm body 3 has a pair of holes 19. During the aforementioned sliding of the holding insert 6 in the arm body 3 the lateral protrusions 18 of the holding insert 6 are clicked into the holes 19 of the arm body 3, whereby a positive locking takes place by a click-lock connection. The protrusions 18 are spring- biased and can be pushed inwardly to allow insertion and when they reach the holes 19, the bias pushes the protrusions 18 into the associated holes 19 and thereby the locking is complete. The holding insert 6 has also a U-shaped profile. The two legs of the "U" can be moved by a slight force away from each other by the elasticity of the material. The loading units 5a, 5b and 5c have respective lateral protrusions 10a and 10b (as shown in Fig. 2 at the loading unit 5c) and in the wall of the holding insert 6 elongated openings 11a and lib are provided to receive the lateral protrusions 10a and 10b of the holding insert 6 and to fix its position in the holding insert 6 allowing a limited sliding along the length of the openings 11a and lib.

Loading units 5a, 5b and 5c have respective lower end parts 22 all having a respective nest 13 for receiving and holding shaft of the associated one of the top rollers 9a, 9b and 9c. In the loading units 5a, 5b and 5c respective dead end bores are provided in which an associated loading element 12 can be inserted. The loading element can be a pneumatic member or a metal helical spring. In the exemplary embodiments shown in the drawing helical springs represent the loading elements 12. In an assembled position one end of the loading element 12 is supported by the bottom of the holding insert 6 and the other end of the loading element 12 is supported by the bottom of the bore made in the associated loading unit 5a, 5b and 5c. Figs. 2c and 2d show the cross sections of the loading units 5a, 5b and 5c wherein the protrusions 10a and 10b can be observed in Fig. 2c and in Fig. 2d the rectangular shape of the lower part 22 is shown. The holding insert 6 carries the loading units 5a, 5b and 5c in the way it allows the limited axial movement thereof in the direction shown by arrow S (visible in Fig. 2 at the loading unit 5a) and owing to the rectangular cross section of the loading units 5a, 5b and 5c the turning of these units around their own axis is blocked. The rectangular cross section of the part 22 of the loading units 5a, 5b and 5c (which can be seen in Fig. 2d) fits into the respective rectangular nests provided in the holding insert 6 and allows a limited axial movement possible and blocks their turning. The protrusions 10a and 10b provided on the part 22 delimits the axial displacement of the loading units 5a, 5b and 5c in the range defined by the length of the openings 11a and lib in which the protrusions 10a and 10b are inserted. The protrusions 10a and 10b can slide in the openings 11a and lib during loading and unloading of the top arm 100.

An important feature of the design of the holding insert 6 lies in that the loading units 5a, 5b and 5c can be identical. The differences that might be required can be realized by providing different positions for the loading units 5a, 5b and 5c in the holding insert 6. If the first loading unit 5a requires a different loading direction than the direction of the other two loading units 5b and 5c, this can be realized by providing a different direction in the holding insert 6 for the nest receiving the loading unit 5a. If the load that should be provided by the loading unit 5b must be e.g. higher than the load provided by the loading unit 5c, the nest 13 for the loading unit 5b should be made shorter, so that the bias as preload acting on the loading element 12 in the loading unit 5b will be higher, consequently the loading provided by the loading unit 5b will be higher.

Fig. 3 shows a partially exploded view of a further embodiment of the top arm 100. Compared to the previous embodiment holding insert 26 has a different shape with a closed structure where respective cavities are provided which are separated by respective separation walls 35. Loading units 25a, 25b and 25c are inserted in the associated cavities and fixed by pins fitted into holes 27 in the loading units and holes 28 made in the holding insert 26. The holding units 25a, 25b and

25c are pivotally fixed around the pins inserted into the holes 27 and 28, and they are moved according to the loading or unloading positions of the nests 13 for the top rollers 9a, 9b and 9c. In the assembled position of the holding insert 26 in arm body 23, the holes 28 in the holding insert 26 are covered by the walls of the arm body 23 and the pins in the holes 27 and 28 are blocked against axial movement for the sake of the safe operation of the loading units 25a, 25b, 25c. For receiving upper ends 32 of loading elements respective nests 30 are formed on the bottom of the associated cavity in the holding insert 26 at appropriate locations. The cross section at the plane A-A of the loading unit 25c can be seen in Fig. 3b. Nests 13 for receiving and fixing the shafts of the associated one of the top rollers 9a, 9b and 9c are formed on parts 31 of the loading units 25a, 25b, 25c. The loading units 25a, 25b and 25c are mounted into the holding insert 26 and the holding insert 26 is assembled into the arm body 23 practically the same way as in the previous embodiment, i.e. by aligning forward surface 33 on the holding insert 26 on the surface 34 on the arm body 23 and inserting a pin into the hole 29 of the holding insert 26 and into hole 24 of the arm body 23. Alternatively, the holding insert 26 can be fixed e.g. by a screw or in any other convenient way to the arm body 23 on the upper side of the arm body 23. Fig. 4 shows a further embodiment of the top arm 100 in a partially exploded view. The holding insert 26 shown in Fig. 3 can be used in a different way in this embodiment. Every loading unit 45a, 45b and 45c has protrusions on both sides similar to protrusions 36 on the loading unit 45c which can be seen on the separate sectional view in Fig 4b taken from the direction "A". Pressing the loading unit 45c against the holding insert 26 the protrusions 36 can be clicked into a corresponding holes 37 in the holding insert 26 and the protrusions 36 at both sides serve as an axis of the associated loading unit 45c.

The loading units 45a, 45b, 45c are able to be turned around their respective axes, so they can be moved up and down against a spring force. After the holding insert 26 has been positioned into the arm body 23, the protrusions 36 will become covered by the walls of the arm body 23, and this ensures safe operation for the loading units 45a, 45b and 45c.

In case of the embodiment shown in Fig. 2 the holding insert 6 had a sufficient elasticity to become widened to the extent as required by the insertion of the loading units 5a, 5b and 5c. In the embodiment shown in Fig. 4, the part 38 of the loading inserts has respective protrusions 36 at both sides which are spring biased and are retractable. In this way the protrusions 36 can be clicked easily into the holes 37 of the holding insert 26 which is now rigid and cannot be forced to become widen.

The top arm 100 designed according to the present invention has a number of preferred properties, which come in part from the fact that uniform components can be used in all required loading locations, whereby the assembly gets simpler and the number of parts is reduced. In spite of the predominantly uniform components the individual design for different applications has been retained, as the different axial directions for certain loading units can be realized by manufacturing the axes of the corresponding nests with differing angles of inclination. Furthermore, in case the load provided by the different loading units should be different, this can be attained by using the same loading units but providing different heights (abutting surfaces) for the nests 30 or 13 associated with the particular loading units.

In this way the advantages of having basically identical components, the individual adjustability has been retained.

Owing to the uniform general design the assembling and installation works of the top arm 100 is possible without the need of any individual change of the geometry, and this further reduces the manufacturing costs.

In case the positions of the bottom and of the top cylinders should be changed in the spinning frame, the top arm 100 can be adjusted to such changes in an easy and efficient way by changing only the holding insert or perhaps the holding insert equipped with loading units.