Device for compensating changes in roving winding tension in spinning machine

Abstract

In a flyer frame, winding of rovings is performed by utilizing the difference in rotation rate between a flyer and a bobbin. Therefore, it is necessary to reduce the rotation rate differences with increase of the bobbin diameter. The bobbin is driven through one of a pair of cone drums around which a belt is stretched, and the rotation rate of the bobbin can be adjusted by changing the belt position along the length of the cone. A device for compensating changes in roving winding tension comprises a link mechanism having at least two elements and disposed to connect a belt shift for moving a belt with a moving member capable of intermittent movement at a constant pitch. The link mechanism is moved by the moving member along a fixed guide member having a cam surface while part thereof is engaging the cam surface of the fixed guide member. By the cooperative action of the cam surface and link mechanism, the constant-pitch intermittent movement of the moving member is converted to a desired movement of the belt, thus compensating the changes of the roving tension.

Description

BACKGROUND OF THE INVENTION

This invention relates to a bobbin driving device for a flyer frame in which winding of rovings is performed by utilizing the difference in rotation rate between a flyer and a bobbin. More particularly, the invention relates to a device for compensating changes in roving winding tension in the bobbin driving device of the type described, which can change the rotation rate of the bobbin so as to compensate the changes in tension on the rovings being wound.

In a flyer frame, winding of rovings is generally performed by utilizing the difference in rotation rate between a flyer and a bobbin, and it is necessary to reduce this difference of the rotation rate with increase of the bobbin diameter. For this purpose, a pair of cone drums are generally employed and they are so disposed that the rotation rate of the bobbin is changed appropriately. More specifically, since the roving winding tension is generally fixed under certain conditions, the cone drums having a certain diameter-length curve, which enables maintenance of this winding tension, are employed. However, the rovings to be treated in one flyer frame are not always under the same conditions, but in general, various rovings different in winding conditions have to be treated. In case the cone drums designed to take up rovings of certain conditions are used for winding rovings of different conditions, the rotation rate of the bobbin is not reduced in harmony with increase of the bobbin diameter, resulting in perpetual change of the tension on the roving being wound, and therefore, bad influences are given to the wound roving.

In order to eliminate such bad influences due to the tension change occurred where rovings of different conditions are wound, it has heretofore been proposed to exchange cone drums or to change the feed pitch of a belt stretched around paired cone drums. In the case of the former, cone drums should always be exchanged because conditions of rovings to be treated are not identical, and in fact, it is not possible according to this method to attain optimum compensation of the tension change. In the case of the latter, since the constant feed pitch is maintained throughout the operation of winding a roving of certain conditions, the collective change of tension throughout the winding operation can be compensated to some extent but if tension changes exceeding the allowable range are temporarily brought about during the winding operation, it is quite impossible to compensate such individual tension changes. As means for overcoming this defect, there has been proposed a device in which the variable pitch feeding of a belt is effected by utilizing a cam mechanism or the like. In this case, changes of the tension owing to the difference of conditions among rovings can be compensated relatively effectively, but this conventional device has a complicated structure including two long racks and a differential gear mechanism and further, this device has such a mechanical defect that the belt hung on cone drums has to be shifted in the twisted or unnatural state. Thus, no practical device capable of complete compensation of the tension has been developed as yet.

It is therefore a primary object of this invention to provide a device for compensation of changes in roving winding tension, which in spite of a very simple structure can overcome the foregoing defects involved in conventional devices and which can wind rovings constantly under a uniform tension without necessary of exchanging cone drums regardless of variations of roving winding conditions.

SUMMARY OF THE INVENTION

In a flyer frame, winding of rovings is generally performed by utilizing the difference in rotation rate between a flyer and a bobbin. Accordingly, it is necessary to reduce this difference of the rotation rate with increase of the bobbin diameter. The bobbin is driven through one of a pair of cone drums around which a belt is disposed and the rotation rate of the bobbin is changed by changing the belt position.

The device of this invention for compensating changes in roving winding tension for use with a spinning machine comprises a link mechanism having at least two elements and disposed to connect a belt shift for moving a belt with a moving member capable of intermittent movement at a constant pitch. The link mechanism is moved by the moving member along a fixed guide member having a cam surface while part thereof is engaging the cam surface of said fixed guide member. By the cooperative action of the cam surface and link mechanism, the constant pitch intermittent movement of the moving member causes a desired movement of the belt. The foregoing primary object of the invention can be attained by the above arrangement.

BRIEF DESCRIPTION OF THE DRAWING

The above and other objects and advantages of this invention will become more apparent from reading the following detailed description in conjunction with the accompanying drawing, in which corresponding reference characters indicate corresponding portions throughout the drawing, and in which:

FIG. 1 is a perspective view showing a bobbin driving system of a spinning machine provided with the device of this invention for compensating changes in roving winding tension;

FIG. 2 is a view showing the front of the bobbin driving system of FIG. 1 in roving winding operation; and

FIG. 3 is a perspective view showing the main parts of another embodiment of the device of this invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring now more particularly to FIG. 1 of the drawing, a device constructed in accordance with the principles of this invention is illustrated therein. The device is in the state that the winding of a roving has been completed. A belt 3 is stretched around a driving cone drum 1 and a driven cone drum 2 and its position on the drums 1 and 2 is held by an upper frame 4 and a lower frame 5. A member 6 for connecting both the frames 4 and 5 is connected to one end of a belt shifter 7. As in the known devices, the belt 3 is allowed to slide on the cone drums 1 and 2 by movement of the belt shifter 7 so that the rotation rate of a bobbin (not shown) connected with the cone drum 2 is gradually reduced. The other end of the belt shifter 7 is connected to one element of a link mechanism, which comprises two link elements 8 and 9, in a manner allowing the element 8 to turn. A roller 18 is supported for rotation on a pin 17, which serves to pivotably connect one element with the other. The link element 9 is turnably connected to a moving member or a rack 10. As in the known devices, this rack 10 is engaged with a pinion 13 mounted on a rotary shaft 12, the pinion 13 being rotated in a known manner by lowering of a weight 11. Intermittent movement of the pinion 13 is provided by an arrangement comprising ratchets 16, and ratchet wheel 15 connected with the shaft 12 through a train of relatively small gears 14. Therefore, the rack 10 is intermittently moved toward the left, as shown by an arrow in FIG. 2, by intermittent movement of the pinion 13.

An L-shaped plate 19 is fixed to the machine frame substantially above the rack 10, and a plurality of positioning means or bolts 20 are adjustably mounted on the horizontal portion of the L-shaped plate 19 and the lower end of each bolt 20 is fixed to the upper surface of a flexible guide plate 21. Accordingly, various cam surfaces are selectively formed on the lower surface of the guide plate 21 by adjusting appropriately the positions of the bolts 20. During the roving winding operation, the lower surface of the guide plate 21 is always in contact with the roller 18, and the latter is successively rolled on the lower surface of the guide plate 21 with movement of the rack 10. A spring 26 is stretched between pins for connecting respectively the belt shifter 7 and the rack 10 to the link mechanism to prevent further expansion of the elements 8 and 9 of the link mechanism when the rack 10 is returned to the position of initiation of winding after completion of one winding cycle. In the device of this invention, however, further expansion of the link elements 8 and 9 can also be effectively controlled, if another guide plate designed to have likewise a cam surface is disposed to form a groove-like path in which the rotary roller 18 is engaged. In this case, at the step of returning the rack 10 to the position of initiation of winding, further expansion of the link elements is restricted by the lower and upper cam surfaces; and hence, provision of the spring 26 is not absolutely necessary in the device of this invention.

The link mechanism need not indispensably be of the two-element construction, but it may be, for example, of the four-element construction. A screw rod or the like can be used instead of a combination of the rack 10 and pinion 13 for movement of the belt shifter 7.

In operation, in pause of the engagement of both the ratchets 16 with the ratchet wheel 15, the weight 11 is lowered to rotate the pinion 13 and the rack 10 is moved toward the left in the drawing by a distance corresponding to the amount of the rotation of the pinion 13. Since the guide plate 21, the cam surface thereof being adapted to the spinning conditions of the roving to be wound, is always in contact with the roller 18, the belt shifter 7 causes an irregular movement of the belt 3 in correspondence with the ups and downs of the cam surface. More particularly, when the roller 18 rises on the cam surface of the guide plate 21, the link elements 8 and 9 are contracted and the shift amount of the belt shifter 7 is reduced, and when the roller 18 descends the cam surface, the link elements 8 and 9 are expanded; hence, the movement or displacement of the belt shifter 7 is made larger by a distance proportional to the expansion of the links 8 and 9 than that of the rack 10. Accordingly, in case various rovings differing in spinning conditions are wound by a common flyer frame, if a cam surface corresponding with the conditions of the individual roving to be wound is formed in advance on the guide plate 21 by adjusting the bolts 20, the shift amount of the belt 3 is automatically adjusted and the roving winding tension can be maintained at a constant level throughout the winding operation, i.e., from beginning to end of winding.

Although in the above embodiment the cam surface of the guide plate is adjusted in correspondence with the conditions of the roving to be wound, it is also possible according to the invention to select a proper guide plate depending on the spinning conditions from an assortment of guide plates each having a cam surface previously adapted to respective spinning conditions.

Another embodiment of the guide plate 21 is shown in FIG. 3. In this embodiment, brackets 23 each having an adjustment long slot or hole 22 are fixedly secured to the machine frame and respective connecting pins 25 provided to the ends of connected link elements 24 are adjustably fitted in corresponding holes 22 in a conventional manner. In this structure, if the vertical positions of the connecting pins 25 are appropriately adjusted, various cam surfaces can be formed on the surface of each link element 24 as in the foregoing embodiment. Thus, if the links 24 are so adjusted that an appropriate cam surface is formed depending on the spinning conditions of a roving to be wound, the roller 18 rolling while making contact with the lower surface of each link 24 moves up and down and therefore, during the winding operation, the belt shifter 7 can move the belt 3 with a displacement smaller or larger than that of the rack 10, resulting in obtaining good wound rovings.

Also, in this embodiment, it is possible to provide another link mechanism below the link mechanism including the link elements 24 to form a groove-like path between both the link mechanisms for the roller 18 to be fitted therein. In this case, the spring 26 need not be provided. In FIG. 3, the guide means comprises a link mechanism including three link elements, but the number of the link elements can be increased or decreased according to the need.

In each of the foregoing embodiments, the roller 18 forming part of the link mechanism is engaged with the guide means composed of the guide plate 21 or the guide links 24, but another part of the link mechanism can be engaged with the guide means. Further, the fitting position of the guide means is not limited to the position above or below the link elements 8 and 9 but it may be located at a position lateral to these link elements. In other words, it is sufficient if the guide member is disposed at a position apart by a certain distance from the movement locus of the link elements 8 and 9 so that it is engaged with at least a part of the link mechanism including the link elements 8 and 9.

As is apparent from the foregoing description, in the device of this invention, the integral fixation of the belt shifter and rack, which is generally adopted in the conventional devices, is separated and divided and both the separated members are connected with each other through a link mechanism including at least two link elements, and concurrently, a guide means forming a cam surface at a position apart by a certain distance from the movement locus of the link elements is disposed so that it is engaged with the link mechanism. In the above structure, if the cam surface of the guide means is appropriately selected or conditioned, during the winding operation, the belt shifter can be moved irregularly in the state desired so that the roving winding tension can be maintained at a constant level throughout the winding operation, i.e., from beginning to end of winding, with the result that a good wound roving free of unevenness can be obtained. Further, the device of this invention is easily applicable to the conventional flyer frames if only minor modifications are made, and the changes of the roving winding tension can be compensated easily at any time with use of the device of this invention which has a very simple structure as compared with the conventional device. Thus, various advantages can be attained by the device of this invention.

While the invention has been illustrated and described with reference to preferred embodiments thereof, it is to be understood that various changes in the details of constructions and the arrangement and combination of parts may be made without departing from the spirit and scope of the invention. What we claim is:

Claims

1. A device for compensating changes in roving winding tension in a spinning machine, comprising a pair of cone drums mounted for rotation in said spinning machine, a belt-like member stretched around said cone drums to transmit rotation of one of said cone drums to the other, a belt shifter associated with said belt-like member to move said belt-like member along the length of said cone drums, a moving member capable of movement to energize said belt shifter, a link mechanism including at least two link elements pivotably connected together, said belt shifter being connected through said link elements with said moving member, and guide means having a cam surface at a position apart by a predetermined distance from the movement locus of said link mechanism, a part of said link mechanism being engaged with the cam surface of said guide means so that the movement of said moving member is transferred to said belt shifter while being subject to the influence of said cam surface.

2. The device as set forth in claim 1, wherein said guide means is composed of a flexible material.

3. The device as set forth in claim 2, wherein said guide means is suspended and supported by adjustable means and the cam surface of said guide means is adapted to spinning conditions of a roving to be wound by adjustment of said adjustable means.

4. The device as set forth in claim 3, wherein said adjustable means are bolts.

5. The device as set forth in claim 2, wherein said part of said link mechanism to be engaged with the cam surface is composed of a roller connected at a connection of said link elements.

6. The device as set forth in claim 5, wherein said two link elements are biased toward each other by a resilient member to ensure the engagement of said roller with the cam surface.

7. The device as set forth in claim 1, wherein said guide means is composed of a link mechanism including a plurality of members, and every two adjacent members are pivotably connected to each other, and individual members are supported so that their positions are changed with respect to said link mechanism connecting said belt shifter with said moving member.