FIELD OF THE INVENTION

The present invention relates to an improved top arm used in the drafting arrangement of textile spinning and roving frame machines. More particularly, this invention relates to an improved method of mounting the top arms onto the textile spinning and roving frame machines.

BACKGROUND OF THE INVENTION

In textile spinning technology, roving frames are used to convert textile slivers of considerable thickness into a thin form called roving. Then the rovings are converted into a further thin form called yarn in ring spinning frames. In both roving and spinning frames, drafting arrangement plays a key role in the above said conversion processes. The drafting arrangement is provided with three bottom cylindrical rollers i.e. front, middle and back rollers. The top arms are provided above the bottom rollers with the top rollers being fixed on the lower side of said top arms. The lower side of each top arm is provided with three pairs of top rollers, i.e. front, middle and back rollers which make pair with bottom front, middle and back rollers respectively. The said top rollers are encompassed with cots and aprons. The said top arms provide loading action on the slivers and rovings which pass in between the top and bottom rollers. The top arms, also called as guide arms or weighting arms, assist the drafting process in order to convert slivers into rovings in roving frames and to convert rovings into yarns in spinning frames. In textile roving and spinning frames, single top arm serves for two spindles. The total number of top arms in a machine frame is equal to half the number of spindles.

In a known method of top arm mounting in existing roving and spinning frames, a lengthy round bar is inserted into the hollow member of a plurality of top arms which is to be rigidly fixed with said bar. Then the said bar is rigidly fastened with the machine structure at both of its ends. Then the top arms and the bar are gripped together by suitable fastening means to avoid free rotating motion. After said fastening, the position of the top arm along with top rollers is set against the bottom rollers so as to get uniform drafting loads among all the top arms in the machine. This setting is an additional work which is disadvantageous. After some period of time, the top arm gets slip on the round bar due to deformation. Because of that the load between the top roller and the bottom roller (drafting load) is reduced. To maintain favourable drafting load, the top arm has to be set at correct position again and again at periodic intervals. Further, in case of any problem in a top arm mounted at the middle of the bar, the entire top arms have to be removed from the bar of the machine frame to provide replacement, which is time consuming and disadvantageous.

In another known method of top arm mounting in existing roving and spinning frame machines, a polygonal tube or a polygonal bar is rigidly fastened to the machine structure. The member of the top arm which is to be rigidly fixed to the machine structure is placed on the upper side of the polygonal tube or polygonal bar. Then an additional component which is semi-polygonal in shape is placed below the lower side of the said tube or bar. Both the top arm member and the additional member are fastened together using screws, nuts, bolts so that both the fixed and additional components are gripped tightly onto the tube or bar. In this method, the said additional component increases the cost of the top arm. The cost is significant when calculated for the entire length of the machine frame. To get uniform load among all the top arms in the machine, some additional fastening means such as washers are provided with the additional component during load setting. This process takes very long time during installation of top arms on the machine frame.

OBJECTS OF THE INVENTION

To overcome the above disadvantages and to erect the top arms on the machine frame at a faster rate, a new methodology is arrived for mounting the top arms as explained in the foregoing description.

It is an object of this invention to provide an improved top arm arrangement in textile roving and spinning frame machines.

It is another object of the invention to provide a fast, user friendly and cost effective method for mounting the top arms onto the textile roving and spinning frame machines.

SUMMARY OF THE INVENTION

This invention provides an improved top arm arrangement for use in textile roving and spinning frame machines. According to this invention, the textile machine comprises a plurality of top arms in the drafting arrangement, longitudinal tube for holding the top arm, wherein said top arm is fastened in the longitudinal tube itself. The top arm is fastened in the longitudinal tube through the holes provided in said tube. Advantageously, the top arm is provided with at least a fastening means such as nut and being mounted over said longitudinal tube. Advantageously, the top arm comprises a fixed component and said fastening means is provided in the fixed component. Advantageously, a screw is inserted into the hole provided in said longitudinal tube in order to lock with said nut of fixed component.

According to an embodiment of this invention, the fixed component of the top arm which is to be rigidly fixed on the machine structure is provided with a nut. The polygonal tube or bar is provided with a through hole or a tapped hole for inserting the screw or to receive the screw from the nut. The polygonal tube or bar shall be provided with both through hole and/or tapped hole in two different faces of the said tube or bar. Then the fixed component of the top arm is placed on said polygonal tube or bar which is either already fastened with the machine or to be fastened with the machine after top arm mounting. The fixed component of the top arm and the polygonal tube or bar has similar shapes at the mating area. The geometry of the similar shape at the mating area includes minimum two sides or curves or both. Then the fixed component of the top arm and the polygonal tube or bar are fastened using screw and nut. While fastening, the mating faces of said top arm and the polygonal tube or bar grips together. The tightening force on the screws applies the gripping force on the mating surfaces. The said gripping force and the geometry of the mating area restrict the slip of top arm on the tube or bar during loading of the top arms. It is also optional to provide more than one screw and holes in some other faces of the polygonal tube or bar which can act as extra support for the top arm preventing free rotation.

According to further embodiments of this invention, the fixed component of the top arm which is to be rigidly fixed on the machine structure is provided with an element having a hole to hold a screw or both nut and an element having a hole to hold a screw. Then the fixed component of the top arm is fastened to the polygonal tube or bar.

The present invention is advantageous since there is no need for an additional provision to set the top arm on the machine to get required load between the top rollers and the bottom rollers. The mating of similar shapes and the close dimensional tolerances of the components of the top arm ensures proper positioning of the top arm in the machine to get required load between the top rollers and the bottom rollers. The top arm is directly mounted on the machine i.e. polygonal tube or bar, and fastened in the longitudinal tube itself without any additional components. Only fasteners are used for mounting the top arms.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates an existing method of mounting the top arm in textile machines.

Figure 2 illustrates another existing method of mounting the top arm in textile machines.

Figure 3 illustrates yet another existing method of mounting the top arm in textile machines.

Figure 4 illustrates a method of mounting the top arm in textile machines according to an embodiment of the present invention.

Figure 5 illustrates a method of mounting the top arm in textile machines according to another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to figure 1, top arm (1) used in existing textile machines using one of the well known mounting techniques is depicted. The top arm (1) has a fixed component (2) at its far end. A lengthy round bar (3) is inserted into the hollow member in the said fixed component (2) of a plurality of top arms which is to be rigidly fixed with said bar (3). Then the said bar (3) is rigidly fastened with the machine structure at both of its ends which is not shown in the figure. The fixed component (2) of the top arm (1) is provided with screw holding elements (4) at the inner face as shown in the figure. Then a screw (5) is provided and tightened to grip the bar (3). An extra screw (5) is provided on another screw holding element (4) which grips the screw holding the bar (3). This acts as an extra support and avoids free rotating motion of the top arm (1) to some extent. Figure 2 shows similar arrangement wherein two individual screw holding elements (4) are fastened with screws (5), said screws grips the round bar (3) directly at two different points. After said fastening, the position of the top arm along with top rollers is set against the bottom rollers so as to get uniform drafting loads among all the top arms in the machine which is not shown here. This setting is an additional work which is disadvantageous. After some period of time, the top arm (1) gets slip on the round bar (3) due to deformation. Because of that the load between the top roller and the bottom roller (drafting load) is reduced. To maintain favourable drafting load, the top arm (1) has to be set at correct position again and again at periodic intervals. Further, in case of any problem in a top arm (1) mounted at the middle of the bar (3), the entire top arms have to be removed from the bar (3) of the machine frame to provide replacement, which is time consuming and disadvantageous.

Referring to figure 3, another existing method of top arm mounting is depicted. A lengthy polygonal tube (6) is rigidly fastened to the machine structure at both the ends which is not shown here. The fixed component (2) of the top arm (1) which is to be rigidly fixed to the machine structure is placed on the upper side of said polygonal tube (6) as shown in the figure. Then an additional component (7) which has semi-polygonal inner profile at mating surface is placed below the lower side of the said tube (6). Both the top arm fixed component (2) and the additional component (7) are fastened together using screws (5) and/or other fastening means so that both the said components are gripped tightly onto the tube (6). In this method, the said additional component (7) increases the cost of the top arm (1). The cost is significant when calculated for the entire length of the machine frame. To get uniform load among all the top arms in the machine, some additional fastening means such as washers (8) are provided in between the fixed component (2) and the additional component (7) during load setting. This process consumes very long time during installation of top arms on the machine frame.

Figure 4 depicts the method of mounting top arm in textile machines according to an embodiment of the present invention. The fixed component (2) of the top arm (1) which is to be rigidly fixed on the machine structure is provided with a nut (9) at its inner surface. The polygonal tube (6) or bar is provided with a through hole for inserting the screw (5) and to lock the said screw (5) with the nut (9) as shown in the figure. This method eliminates the additional component (7) used in the existing methods and also the top arm is fastened in the polygonal tube (6) itself.

In another embodiment of this invention, the polygonal bar (6) or tube shall be provided with both through hole and tapped hole in two different faces of the said bar (6) as shown in figure 5. Then the fixed component (2) of the top arm is placed on said polygonal bar (6) or tube. Then the screw (5) is fastened with the nut (9) provided in the fixed component (2) of the top arm. Another screw (5) disposed in the screw holding element (4) is tightened which additionally grips said polygonal bar (6). While fastening the top arm (1) and the polygonal bar (6) using screws (5), the mating faces of said top arm (1) and said polygonal bar (6) grips together. The tightening force on the screws (5) applies the gripping force on the mating surfaces. The said gripping force and the geometry of the mating area restrict the slip of top arm on the bar during loading of the top arms.

Alternatively, the polygonal bar or tube (6) shall be provided with more than one through hole or more than one tapped hole. In this case, the fixed component (2) of the top arm is provided with either nuts or screw holding elements accordingly for fastening the same with the polygonal tube or bar (6).

In view of the present disclosure which describes preferred and best modes for mounting the top arm in textile roving and spinning machines, modifications and variations would present themselves to those skilled in the art without departing from the scope and spirit of this invention. Any modifications and variations coming within the meaning and range of equivalency are considered within the scope.

We claim:

1. A textile machine comprising a plurality of top arms in the drafting
arrangement;

longitudinal tube (6) for holding the top arm;

wherein said top arm is fastened in the longitudinal tube (6) itself.

2. A textile machine comprising a plurality of top arms as claimed in claim 1, wherein said top arm is fastened in the longitudinal tube (6) through the holes provided in said tube (6).

3. A textile machine comprising a plurality of top arms as claimed in claim 2, wherein said top arm is provided with at least a fastening means (9) and being mounted over said longitudinal tube (6).

4. A textile machine comprising a plurality of top arms as claimed in claim 3, wherein said top arm comprises a fixed component (2);
said fastening means (9) is provided in the fixed component (2).

5. A textile machine comprising a plurality of top arms as claimed in claim 4, wherein said fastening means (9) is a nut.

6. A textile machine comprising a plurality of top arms as claimed in claims 4 & 5, wherein at least a screw (5) is used to lock the nut (9) of said fixed component (2) with said longitudinal tube (6).

7. A textile machine comprising a plurality of top arms as claimed in claim 6, wherein said screw (5) is inserted into the hole provided in said longitudinal tube (6) in order to lock with said nut (9) of fixed component (2).

8. A textile machine comprising a plurality of top arms as claimed in claim 1, wherein said longitudinal tube (6) is polygonal in shape and can be a polygonal bar.

9. A textile machine comprising a plurality of top arms as claimed in claim 2, wherein said hole is a through hole or a tapped hole.