JPS6366928B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a draft device in a pneumatic spinning machine, and the draft device is indispensable for the pneumatic spinning machine. It is no exaggeration to say that the quality of the spun yarn produced is determined by There are various factors that affect the quality of the spun yarn in the drafting device, and among them, the free gauge area between the tip of the apron and the front roller nip point, and the airflow generated in the front roller section have a large influence. That is, until the sliver delivered from the middle roller is gripped at the nip point of the front roller, all the single fibers are temporarily located in the middle between the rollers, and none of them are gripped, i.e., floating. A fiber is formed, but at this time, the fiber sent out from the middle roller advances under a certain clamping pressure due to the apron attached to the middle roller, so it cannot be said that it is completely gripped. It has almost the same function as the grip state. Further, after passing through the apron, the area between the front roller nip points is completely free.
At this time, even if the fiber is released from the restraint of the middle roller and becomes a floating state, the tip of the fiber is held by the front roller by the apron clamping pressure.
If the draft progresses at the same speed as the middle roller circumferential speed, ideal drafting will occur and the floating fibers will not cause draft unevenness, but in reality, even in the free gauge area, the floating fibers will cause the front roller circumferential Due to the influence of other high-speed fiber groups, the point at which the speed increases is distributed in front of the gripping point of the front roller, that is, on the middle roller side, and furthermore, this constantly fluctuates, causing draft unevenness.

Also, sliver or Shino has a draft ratio of D
If the circumferential speed of the front roller is FV and the circumferential speed of other rollers is MV1~n, the draft will be gradual due to the relationship of D=FV/MV1~n, that is, FV>MV1~n, but at this time, the back roller and Since there is no fiber control means such as an apron between the middle rollers, there is almost no drafting, which is about 1.2 to 3.0 times as much in general drafting devices and about 2 to 9 times as much in the drafting device of the present invention. Therefore, it can be said that substantial drafting occurs between the middle roller and the front roller.

From the above, it can be seen that the front roller rotates at the highest speed compared to the other rollers. At this time, as each roller rotates, an airflow is generated near the nip point of the roller, but especially at the front roller section, which rotates at high speed, the airflow generated at other roller sections is laminar. , turbulence occurs. Therefore, under the influence of the turbulent flow generated in the front roller section in the free gauge area mentioned above, the fiber arrangement of the sliver is disturbed and the fibers are scattered, resulting in unrestrained fibers and hooked fibers at both ends, and furthermore, the sliver width is reduced. When it expands abnormally, the phenomenon becomes noticeable.

Therefore, the above-mentioned phenomenon causes an increase in cotton drop, and furthermore, the hook fiber causes a decrease in yarn strength, and also causes thick yarn sections and thin yarn sections to be formed, which has a great effect on yarn quality such as deterioration of uniformity. It is.

The present invention is a draft device developed based on the above points, and provides a draft device that exhibits good effects in a pneumatic spinning machine.

The present invention will be explained below based on examples.

Figure 1 shows the draft device, with guide 1
The sliver S is pulled out from a can (not shown) via the upper and lower rollers 2a and 2b, which actively rotate while being in pressure contact with one end of the outer periphery, and the apron 3.
It passes through the middle rollers 4a, 4b and the front rollers 5a, 5b equipped with the rollers a and 3b, is directly drafted without going through the roving process, passes through the fluid type twisting device 7, and reaches the take-up roller (not shown).

As described above, the three types of rollers have different circumferential speeds, and are gradually drafted due to the difference in circumferential speed. Further, when the sliver S passes between the rollers rotating under pressure, the adjustment guide 6 is moved between the rollers 2a, 2b and the middle rollers 4a, 4b so that the sliver S is expanded into a flat shape by the pressure of the rollers.
This prevents abnormal expansion of the sliver S width.

Furthermore, the aprons 3a and 3b attached to the middle rollers 4a and 4b, respectively, have the shape of an endless belt, and the aprons 3a and 3b run in conjunction with the rotation of the middle rollers 4a and 4b while being in a pinched state with each other. The clamping positions and clamping pressures of the aprons 3a and 3b affect the spun yarn, such as draft unevenness. Apron 3b is used as a means to prevent this effect.
A tens server 8 is provided inside the tip, and the tens server 8
is fixed by a fixing lever (not shown).
At this time, it is more effective to apply a surface treatment such as Teflon treatment to the sliding surface of the tension bar 8 with the apron 3b in order to reduce frictional resistance. A cradle 9 is attached to the inside of the tip of the apron 3a, and the other end of the cradle 9 is folded back into a substantially triangular shape, and the folded edge 10 is pressed by a spring 12 screwed onto a bearing 11a. It is configured to press the ten server 8 at all times.

The bearing 11a and the bearings 11b, 11c have a substantially U-shaped cross section, and a spring 14 is hung on a fixing pin 13 provided at one end, and the bearings 11a, 11b, 11c are integrated with the cradle 9 and the rollers 2a, 4a, 5a. The shafts 15a, 15b, and 15c are removably held between the side wall 16, the spring end 14a, and the spring 14 having the fixing pin 13 as a fulcrum. Further, the bearings 11a, 11b, and 11c are fitted into a roller guide 17 screwed and fixed to a roller support 18 so as to be rotatable about a fixed support shaft 19, and are mounted on the roller guide 17. By the biasing of the spring 24, the bearing end face 11
d to rotate counterclockwise around the support shaft 19. Also, the known fixed lever 2
The roller 2 fixed by the lock by 0
The rollers 2a, 4a, and 5a, which are provided opposite to the rollers b, 4b, and 5b, always press with a constant pressure. Furthermore, when the fixed lever 20 is unlocked,
In order to restrict the rotation range of the bearings 11a, 11b, 11c, the grooves 21 formed in the plate 22 screwed onto the roller guide 17 are inserted into the bearings 11a, 11c.
It is pivotally connected to guide pins 23 which are respectively fixed to b and 11c, and its rotation range is regulated by the slot 21.

At this time, the most important thing is the apron 3a,
The tip of 3b should be installed close to the front roller nip point. This point will be explained in further detail.

Fig. 2 shows the progress of the fibers during drafting between the aprons 3a, 3b and the front rollers 5a, 5b. Aprons 3a, 3b, for clarity.
The fiber clamping surfaces 3c and 3d are shown lowered to the contact height of the front rollers 5a and 5b.

For good drafting, the sliver in the draft area must have a certain tension (draft force).
As a result, each fiber in the sliver bears part of the tension, and each fiber contacts the surrounding fibers with a certain pressure, creating friction between them to balance the tension (draft force). At this time, it is desirable that each fiber in the draft moves at a constant speed, but this can be achieved by keeping the floating fibers restrained by the middle rollers 4a, 4b or the aprons 3a, 3b for a long time. For this purpose, the contact pressure between the fibers must be above a certain value. Further, if the sliver breaks during drafting, it cannot be drafted, so the strength of the sliver is greater than the drafting force.Furthermore, it is desirable that the drafting force per fiber be smaller than the cutting strength of the fiber so that the fiber does not break. That is, (a) contact pressure between fibers ≧ constant value, (b) sliver strength ≧ draft force, and (c) draft force per fiber ≦ fiber cutting strength, and by satisfying these three conditions. Draft unevenness is minimized.

Furthermore, middle rollers 4a, 4 as shown in FIG.
Considering the draft between F and the front rollers 5a and 5b, if the draft is completely performed, even if each fiber F leaves the gripping point of the middle rollers 4a and 4b, as described above, the front rollers 5a and Until it reaches the gripping point 5b, it advances at the back crawler speed, and only when it reaches the front roller gripping point does it shift to the front roller speed. However, in reality, any of the floating fibers FM will be accelerated before reaching the front roller gripping point. The motion of this floating fiber FM is determined by the value obtained by multiplying the contact friction force per unit between the gripping fibers FH and FS of the front rollers 5a, 5b and middle rollers 4a, 4b and the floating fiber FM by the contact length L. .

Now, a single floating fiber in the draft area
If the FM is moving to a low speed, a dynamic frictional force will act between the floating fiber and the high-speed fiber FH in contact with it, and a static frictional force will act between the low-speed fibers FS. Therefore, if the forward force, that is, the force of the high-speed fiber FH increases, and exceeds the limit of the restraint force in the low-speed fiber FS region, that is, the critical friction force, the floating fiber FM will accelerate before reaching the gripping point of the front rollers 5a and 5b. This causes uneven drafting.

From the above, in order to minimize draft unevenness, it is desirable that the floating fiber FM leaving the middle rollers 4a, 4b travels at the same speed as the middle roller speed until just before it is gripped by the front rollers 5a, 5b. For that purpose, apron 3a,
By keeping the contact pressure between the fibers constant by 3b and maintaining the contact time between the aprons 3a and 3b and the fibers F for as long as possible, the speed of the middle rollers can be maintained at the same speed as the middle rollers until just before they are gripped by the front rollers 5a and 5b. The goal is to move forward at speed.

Therefore, as shown in the second diagram, the tips of the aprons 3a and 3b are placed as close as possible to the nip points of the front rollers 5a and 5b without coming into contact with them, that is, at the positions 3c and 3d shown in chain lines where the free gauge area G is minimized. As a result, the floating fiber FM that has left the middle rollers 4a, 4b is controlled until just before it is gripped by the front rollers 5a, 5b, and it is possible to advance it at the same speed or a similar speed to the middle roller speed without increasing the speed. Draft unevenness is suppressed.

At this time, move the tip of the apron to the front rollers 5a, 5.
As mentioned above, the closer the position is to the b nip point, the better the results will be. However, in reality, due to the mechanism, the tips of the aprons 3a, 3b do not come into contact with the outer peripheral surfaces of the front rollers 5a, 5b, which rotate at a fixed position. It is set by approaching the position.
That is, if the tip of the apron is brought into contact with the outer circumferential surface of the front roller, friction due to the difference in circumferential speed between the aprons 3a, 3b and the front rollers 5a, 5b will cause wear on their contact surfaces, which is undesirable.

Therefore, in consideration of the vibrations generated at the tips of the aprons 3a, 3b and the outer circumferential surfaces of the front rollers 5a, 5b, dimensions are set so that the tips of the aprons 3a, 3b do not come into contact with the outer circumferential surfaces of the front rollers 5a, 5b when set. Due to dimensions, free gauge G is inevitably required.
When the dimensions are set and the JIS (L5119) standard bottom front roller 5b diameter (25 mm) is used, the free gauge G is approximately 10 to 12 mm, and when the bottom front roller 5b diameter (35 mm) is used, the free gauge G is
is about 18-20mm.

Furthermore, the influence of the airflow generated in the front roller section mentioned above on the free gauge area G will be explained in detail based on FIGS. 4 to 6.
The fiber arrangement of the sliver S that has passed through a and 3b is disturbed by the airflow generated near the nip point of the front rollers 5a and 5b rotating at high speed, resulting in scattered fibers and the sliver width is abnormally expanded. I do things.

Furthermore, to explain in detail the outflow route of the airflow,
The airflow is divided into two airflows, and as shown in FIG. 4, the accompanying airflows A-1 and A-2 enter along the outer peripheral surfaces of the top front roller 5a and the bottom front roller 5b. The accompanying airflow A-
1 and A-2 collide with each other in the vicinity of the nip point between the top front roller 5a and the bottom front roller 5b, and the repulsive airflow at that time flows out in the direction of arrows B-1 and B-2. The repulsion air current disturbs the fiber arrangement of the sliver S, causing the sliver to scatter, resulting in a phenomenon in which the unrestricted fibers at both ends and the tips of the fibers are hooked.

Another type of airflow flows between the top front roller 5a and the bottom front roller 5 as shown in FIG.
The accompanying air currents A-1 and A-2 that have entered the vicinity of the nip points of the rollers 5a and 5b along the outer circumferential surface of the rollers 5a and 5b generate repulsive air currents as described above, and flow out in the direction of the arrows B-1 and B-2. At the same time, it flows out toward the yarn path along a path that divides it into two in right-angled outward directions C-1 and C-2. Due to the influence of the airflow, the width of the sliver may be abnormally expanded, or the fiber arrangement may be disturbed, resulting in fibers with unrestricted ends.

As a result, the spun yarn produced is as shown in FIG.
No. 3 is composed of a yarn in a state F5 in which the cotton falls off or is simply wound around the outer periphery, and in the wound state F5, the yarn hardly functions to strengthen the yarn and conversely causes neps and the like, resulting in a decrease in yarn quality.

In addition, since the fiber F4, whose tip is in a hooked state, is twisted while still in the hooked state, the effective winding length of the fiber F6 decreases, leading to a decrease in yarn strength, and forming thick yarn portions and thin yarn portions. It can also cause Furthermore, an imbalance in fiber density due to an abnormal increase in fiber width, etc., combined with the above factors, deteriorates the quality of the yarn and causes poor hand feel.

The above phenomenon can be prevented by bringing the tip of the apron close to the front roller nip point. To explain this point in detail based on the embodiment shown in FIG. 7, FIG. 7 shows that for the front roller nip point,
This shows an embodiment in which the apron nip points are arranged close to each other in an deviated state, and the height of the tension bar 8 is deviated upward H with respect to the nip points of the front rollers 5a and 5b.
The sliver S that has passed between the aprons 3a and 3b is placed on the accompanying airflow A-1 generated by the rotation of the top front roller 5a, and the front rollers 5a and 3b are moved without abnormally expanding the fiber width of the sliver S or disturbing the fiber arrangement. Make sure to send it to the nip point of 5b. At this time, by shifting the tip of the lower apron 3b from the upper apron 3a position to the front roller nip point side and bringing it closer to the bottom front roller 5b, the bottom front roller 5b
The airflow A-2 generated at the front roller is caused to flow out A-3 along the lower apron 3b to prevent turbulence generated near the front roller nip point.

Therefore, the influence of air currents can be suppressed to a minimum, and the phenomenon that the fibers are scattered due to the above-mentioned disorder of the fiber arrangement of the sliver, resulting in unrestrained fibers F3 at both ends and hooks F4 at the tips of the fibers, is prevented. .

The sliver S continuously supplied by the draft device described above is introduced into the pneumatic twisting device 7 to produce a spun yarn with a real twist inserted therein. The produced spun yarn is actively drawn out by a take-up roller (not shown), and further wound into a package via a traverse guide and a friction roller.

FIG. 9 shows the triangular state of the sliver S generated at the delivery portions of the front rollers 5a and 5b, where the triangular portion Z1 of the sliver S is caused by the arrangement of the apron tip close to the front roller nip point mentioned above. Scattered fibers caused by uneven draft and disordered fiber arrangement of the sliver;
Abnormal expansion of the sliver width is prevented, and since the triangular portion Z1 of the sliver is generated to a stable constant size Z2, the open end ratio of the fiber F7 is increased without the tip of the fiber becoming hooked.

Therefore, the pneumatic twisting device 7 described above functions effectively, and a spun yarn with excellent yarn strength and uniformity can be obtained.

As described above, in the present invention, by arranging the tip of the apron as close as possible to the front roller nip point of the drafting device, it is possible to suppress draft unevenness, and to prevent scattering of fibers and abnormalities in sliver width due to disordered fiber arrangement. This prevents phenomena such as expansion, and also prevents the occurrence of fibers with unrestricted ends as described above, such as the occurrence of cotton drop and the mere winding of the fibers around the outer periphery of the produced spun yarn. It also prevents curling.

Therefore, a spun yarn with excellent yarn uniformity and yarn strength can be obtained. In addition, since the sliver clamping surface by the apron is flat, the clamping pressure on the sliver is almost constant between the middle and front rollers, and the clamping pressure due to the undulations on the sliver clamping surface, which is common in conventional equipment, is reduced. There is no fluctuation, and as a result, the speed conversion point from the low moving speed given by the middle roller to the high moving speed given by the front roller of each fiber constituting the sliver is constant, and draft unevenness is prevented. be done.

Furthermore, because the sliver clamping surface is inclined upward, even if the distance between the front roller and the middle roller is the same, the actual sliver movement distance is long, and the tip of the apron is closer to the front roller. Since the fibers are held as close as possible to each other, the distance and time for which each fiber is held by the apron becomes longer, and draft unevenness can be better prevented in this respect as well.

[Brief explanation of drawings]

Figure 1 is a partially sectional side view of the draft device;
Fig. 2 is an explanatory diagram of the draft state of the fiber when the apron is brought close to the front roller and when it is not, Fig. 3 is an explanatory diagram of the draft state between the middle roller and the front roller, and Figs. Figure 6 is an explanatory diagram showing the influence of airflow on spun yarn, Figure 7 is a diagram showing the state of airflow near the tip of the front roller and apron in an embodiment of the present invention, and Figure 8 is an illustration showing the influence of airflow on the spinning yarn. FIG. 3a, 3b...Apron, 4a, 4b...Middle roller, 5a, 5b...Front roller, 8...
...Ten server, 9...Cradle, 2a, 2b...
...Bear crawler, 11a... Bearing, 12... Spring, A-1... Accompanied airflow, S... Sliver.

Claims (1)

[Claims] 1. A back roller 2a, middle rollers 4a, 4b equipped with aprons 3a, 3b, and front rollers 5a, 5b along the sliver path traveling direction.
It is a drafting device consisting of aprons 3a and 3b arranged in sequence, in which aprons 3a and 3b run in synchronization with the rotation of the middle rollers 4a and 4b, the upper apron 3a is hung around a cradle 9, and the lower apron 3b is a flat plate. The sliver s is provided by being hung around a tensile server 8 having a shape, and the upper and lower aprons 3a and 3b
The clamping surface of the sliver s is flat, and the tip of the tensile server 8 is brought as close as possible to the front winding space between the upper and lower front rollers 5a, 5b, so that the clamping surface of the sliver s is flat at least. The rollers 5a, 5b side are located above the nip point of the front rollers 5a, 5b, and the tip of the lower apron 3b is brought as close as possible between the upper and lower front rollers 5a, 5b, so that the tip of the lower apron 5b is at least The sliver that has passed through the apron rides on the accompanying airflow A-1 generated by the rotation of the top front roller 5a at a position that is not in contact with the outer circumferential surfaces of the front rollers 5a and 5b, and the sliver is moved onto the front roller by riding on the accompanying airflow. 5a and 5b, and the cradle 9 is urged toward the lower apron 3b with an appropriate pressure by a spring 12 provided on the bearing 11a of the middle roller 4a. Furthermore, by making the heights of the nip points of the back rollers 2a, 2b, middle rollers 3a, 3b, and front rollers 5a, 5b the same, the plane where the sliver is held by the aprons 3a, 3b is a plane connecting the nip points. The sliver S is formed into a plane that is inclined upward in the sliver traveling direction, and the sliver S rises in a straight line with an incline between the aprons 3a and 3b, and after leaving the aprons 3a and 3b, it rides on the accompanying airflow and rises obliquely. A draft device for a pneumatic spinning machine, characterized in that the draft device advances downward and is nipped onto front rollers 5a and 5b.