EA003723B1 - Device for continuous fabric take-down in a knitting machine - Google Patents

Abstract

1. A device for continuous fabric take-down in a knitting machine with one or more needle holders (1, 2) consists of two elastic belts (5, 6) rotated in opposite directions by two horizontal shafts (7, 8) and passing over return members (10, 11) located close to the stitchforming zone and arranged on at least two rests (12, 13) supported by respective drive shafts providing pressing the belts (5, 6) to each other under the action of friction forces transferred to the rests by the drive shafts, characterized in that comprises means (14, 15; 21, 22) which allows the shape of the belts enveloping surfaces to be modified varying the pulling effort locally applied to the knitted material or stockinet. 2. The device according to claim 1, characterized in that the belt shape modification mechanism consists of pressure elements (21, 22) arranged on the rests exercising pressure on the belts locally increasing their tension and, consequently, the pressure upon the stockinet that is the pulling force. 3. The device according to claim 1, characterized in that the means of modification of the form of the tension belts enveloping surfaces increase the contact surface of at least one belts with stockinet. 4. The device according to claim 2 or 3, characterized in that at least one rest (12, 13) is segmented into a plurality of autonomous rests (12a-12g). 5. The device according to claims 1, 3 or 4, characterized in that the means of modification of the form of the tension belts enveloping surfaces is formed by at least one elongated body (21, 22) parallel to the drive shaft axis, the body is mounted on a rest (12) between the axis and the belt the length of which is equal to a certain fraction of the needle holder's length and which is adapted to move axially on rests, and means (17, 18, 23, 24) for displacing said bodies axially, wherein said bodies move the belts away from the rests thus changing the shape of the belts enveloping surfaces. 6. The device according to claim 5, characterized in that said bodies (21, 22) are mounted on the internal or external side of the rests. 7. The device according to claim 5 or 6, characterized in that each elongated body (21, 22) is mounted on endless screws (17, 18) between two nuts (19, 20) retained by rotation, the screws (17, 18) are individually driven by motors (23-26) providing an automatic displacement of said elongated bodies (21, 22) depending on definite knitting zone. 8. The device according to claim 7, characterized in that the elongated bodies (21, 22) are rollers freely or not rotating on endless screws. 9. The device according to claims 1 to 8, characterized in that grooves are provided on the external surface of belts. 10. The device according to claim 9, characterized in that the grooves are parallel to the drive shaft's axis 11. The device according to claim 9, characterized in that the grooves are helical. 12. The device according to claim 9, characterized in that the belts have two systems of crossing helical grooves. 13. The device according to one of claims 1 to 12, characterized in that comprises motors (14, 15) with variable speed of rotation which drive the respective drive shafts (7, 8). 14. The device according to claim 13, characterized in that the motors (14, 15) are two-way motors.

Description

The present invention relates to a continuous tensioning device for a flat knitting machine with one or several needles, containing two elastic belts which are driven by two horizontal shafts in a continuous movement in opposite directions and pass at least along two guide rollers located near the loop formation area and mounted on supports supported by drive shafts, ensuring that the belts are pressed against each other under the action of friction forces transmitted to the supports by driving and shafts.

One such device is described in Swiss Patent No. 633,334 (US Patent No. 4,359,881). The applicant company that developed this device has been using it successfully for about 20 years. It ensures smooth tensioning of the knitwear between the belts under the action of friction-slip, either continuously or as loops form and in close proximity to the loop formation zone.

The belts run along the entire length of the machine, while the tensioning device exerts a uniform tensile force along the entire length and on both sides of the knit. It should be borne in mind that the structure of knitwear, which can be obtained on modern flat knitting machines, are becoming more complex, as is the case, for example, in the production of bulk products. On these machines, you can perform shaped knitting, as well as produce finished products such as pullovers, which the machine not only knits, but also completely trim. With such knitting there is no simultaneous formation of knitted fabrics both on the front and on the back needle beds, and it often happens that one of them is in standby mode in relation to the other during numerous passes of the carriage with knitting locks that control the work of knitting needles, while knitting occurs entirely on the entire opposite needle bed or only in any one of its zones.

Thus, it seems appropriate to provide the possibility of different tensioning of knitted fabrics, which are formed at different times, and, if necessary, automatically vary the tensile force in certain zones across the knitting width, while the structures of the resulting loops can have different shapes and densities in width, for which it is necessary so that the pressure exerted on knitwear may undergo local changes as necessary, in particular for the production of bulk products.

The aim of the invention is precisely the satisfaction of these requirements. To achieve the above purpose, a tensioning device is proposed, characterized in that it provides means for changing the shape of the envelope surface of the belts so as to obtain different tension forces acting on the knitted fabric (s).

Such means of changing the shape of the envelope surface of the belts can be very diverse and can be used both individually and in combination.

In accordance with one of the methods for performing the means for changing the shape of the envelope surface of the tensioning belts, are clamping means mounted on supports that exert pressure on the belts with an increase in their tension.

Due to the increase in the belt tension, the pressure of the drive shaft on the support increases and, accordingly, the friction force, which means the moment acting on the support, and the clamping force with which the belt acts on the knitwear.

In accordance with another method of performing the means for changing the shape of the envelope surface of the tensioning belts, they increase the contact surface of at least one of the belts with knitwear.

In accordance with one of the methods for performing means for changing the shape of the envelope surface of the belts, they are formed on each of the supports, usually divided into segments, by at least one elongated body, the axis of which is parallel to the axis of the drive shaft, which is mounted on the support between this support and belt, the length of which is equal to some part of the length of the bed, preferably less than the length of one segment of the support, and which is installed with the possibility of movement on the supports in the axial direction. Special means are also provided for driving these bodies in the axial direction. These bodies move the belts away from the supports, thereby changing the shape of the envelope surface of the belts.

It is preferable to perform the specified elongated bodies in the form of rollers, freely set along the axis of their movement on the worms between two movable nuts.

Thanks to the use of elongated bodies, in this case rollers, the belt is moved away from the support and, consequently, an increase in its tension.

In order to obtain a local increase in the tension force, it is advisable to divide the supports into several independent sections, that is, those that are independent of each other in terms of setting them in motion with a drive shaft.

It is advisable to provide each elementary support with at least one roller mounted on the inside and / or the outside of the support.

It is also advisable to provide in the device two engines with adjustable speed and two directions of rotation, each of which drives the corresponding shaft.

In the attached drawings as an example, illustrated one of the ways of carrying out the invention, as well as one of its variants.

FIG. 1 shows a cross-section of the upper part of a flat knitting machine with two needle beds equipped with a tensioning device.

FIG. 2 depicts a perspective view of a tensioning device without needle cases.

FIG. 3 shows a perspective view of one of the systems of the tensioning device, in which the belt of this device is partially shown.

FIG. 4 shows a cross-section along line 1U-1U in FIG. 3, while also showing the second tensioning system, which is symmetrical to the first.

FIG. 5 is a cross-section along the line V-V in FIG. 3 with both tensioning systems.

FIG. 6 depicts one of the modifications of the tensioning device.

The flat knitting machine shown in FIG. 1, as well as all known machines, has two opposite needles 1 and 2 fixed to the frame 3. The corresponding grooves 4 are made in the needles, which include needles with their keys (not shown).

Under the needle cases there is a continuous tensioning device, the basic elements of which are similar to those described in TTT-Switzerland patent No. 633 334 (US patent No. 4359881). This device consists of two systems A and B, comprising mainly two endless belts 5 and 6 of smooth rubber or similar material, which are driven by two respective shafts 7 and 8, running parallel to the axis of the machine symmetrically relative to its plane of symmetry 9 , while both belts 5 and 6 also pass through two guide rollers 10 and 11, which are simple metal cylindrical rods of small diameter, supported respectively by two supports 12 and 13, which, in turn, are supported I drive shafts 7 and 8. Supports 12 and 13 are formed by essentially prismatic blocks that run along the entire length of shafts 7 and 8 and have a recess with a cylindrical surface, which they rest on sliding on shafts 7 and 8, while the opposite recess serves a support for guide rollers 10 and 11. Supports 12 and 13 are preferably made of synthetic material with a low coefficient of friction. Elastic belts 5 and 6 give a slight tension, due to which the supports 12 and 13 are pressed respectively to each of the shafts 7 and 8, driven into rotation, as shown by arrows, in opposite directions. Supports 12 and 13 show a tendency to propulsion by friction force from the drive shafts 7 and 8, and as a result of this movement, ideal squeezing of the belts 5 and 6 to each other along the plane of symmetry 9 of the machine occurs, as described in the above-mentioned patent.

FIG. 1 also shows another means for creating various tension forces and described below with reference to this drawing.

FIG. 2 illustrates one of the means of changing the shape of the envelope surface of the tensioning belts. These means are formed by two engines 14 and 15 with adjustable rotational speed, setting in motion the corresponding drive shafts 7 and 8. The operation of these engines is carried out separately, and their direction of rotation can be reversed, as shown by double-headed arrows. You can change the speed of the engines 14 and 15, so that the belts are pressed to each other with more or less force; in other words, it is possible to change the contact surface of at least one of the belts with knitwear, and this change is accompanied by a change in the shape of the envelope surface of the belt and a change in the tension force. The engines also provide the ability to change the tension force in the canvases, which are knitted on each of their two needle beds. Thus, one of the canvases, front or back, can knit faster than the opposite one. One of the belts can be completely stopped, and then the tension will be made only by the opposite belt. The direction of rotation of one of the engines can be reversed so that the corresponding knitted fabric can be pulled up if necessary.

FIG. 2, another improvement can be seen, which is described below with reference to FIG. 3 and 5, illustrating another exemplary embodiment of means for changing the tension force by changing the tension in the belts 5 and 6.

In the supports 12 and 13 (FIG. 3), longitudinal grooves of the Y-shaped profile are made on the sides, such as grooves 16, which run parallel to the axes of the drive shafts 7 and 8. In each of these grooves, worm clamps of the type indicated by the numbers 17 and 18 are installed. These screws are installed nuts 19 and 20, the rotation of which is supported by the profile of the grooves 16. Between these nuts 19 and 20 in each of the grooves 16 are installed tubular rollers, namely the first roller 21 and the second roller 22, located with the possibility of free rotation on the worms 17 and 18, but with the axial direction preventing movement of the movable nuts 19 and 20. Worms 17 can be driven separately by electric motors 23 and 25, and worms 18 by electric motors 24 and 26. With the automatic drive of these engines, shaft and 21 and 22 in the grooves 16 along the support 12. The motors 23 and 24 directly drive the worms 17 and 18 and motors 25 and 26 drive the belts via respective worms 27 and 28.

Due to the presence of the roller under the belt 5, it is possible to change the shape of the envelope surface of the belts by lengthening the path of movement of the belt 5, that is, to obtain a local increase in the tension of this belt. Due to the increased tension of the belt, there is an increase in the force with which the belt is pressed against the opposite belt, or, in other words, an increase in the tensile strength of the knitwear. This is due to a simple increase in the pressure of the drive shaft on the support, that is, an increase in the friction force between the drive shaft and the support.

As can be seen in FIG. 3-5, the rollers can be located both on the inner sides of the supports 12 and 13, that is, on the sides facing each other, and on their outer sides. FIG. 4 also shows that, due to the rollers mounted on the inner sides of the supports, the length of the section of the knitted fabric sandwiched between the straps increases, as a result of which a local increase in the stretch of the knitted fabric occurs.

FIG. 5 shows the zone of the belts 5 and 6 without rollers. In this case, the minimum tension force is achieved.

In the embodiment shown here, there are four pairs of rollers per support. Of course, it is possible to limit the number of rollers to one pair and even to one roller per support. In addition, rollers can be installed only on one of the supports.

The rollers do not necessarily have to rotate on the screws 17 and 18. Therefore, instead of rollers, tubes that have a non-circular cross-section, but, for example, a polygon-shaped cross section, can be used.

They can also be replaced by any oblong body, installed either rotatably or without this possibility.

Another improvement is the implementation of grooved belts, as shown in FIG. 3 in relation to the belt 5. Here the grooves 30 have the form of parallel grooves running parallel to the axis of the system, i.e. parallel to the axis of the drive shaft 7. These grooves 30 contribute to strengthening the adhesion of the belt to the knitwear as well as the adhesion of the front and rear knitwear at the same time, despite what was said, the knitwear slip, which helps prevent its damage due to excessive friction. As a rule, the grooves are made in both belts 5 and in the same way.

In accordance with one of the variants, the grooves may be located inclined with respect to the axis of the system, i.e. be practically spiral. They can also be made crosswise, in two spirals of opposite directions.

FIG. 4 shows that the use of two combined rollers allows you to get a local increase in the stretch of knitwear. FIG. 6 illustrates the possibility of local stretching increase with a single roller. This is achieved by partitioning the supports, for example the supports 12 shown in FIG. 6. Here it is divided into several independent pillars 12a-12d. Using one or two rollers, such as rollers 21 and 22, it is possible to obtain a local increase in the tension of the belt 5 on one or more of the support sections 12a-12d. The support section, which is affected by this additional tension, presses the belt more strongly against the opposite belt, as a result of which the tension force increases. On separate sites can be broken both one of support, and both support.

It is obvious that the guide roller 10 is also divided into several rollers 10a-10d.

A local increase in pressure, in other words, the tension of the belts can also be obtained not by using the rollers described above, but by some other means.

Claims (14)

CLAIM 1. A continuous tensioning device for a flat knitting machine with one or more needle beds (1, 2), having two elastic belts (5, 6), which are driven by two horizontal shafts (7, 8) in continuous motion in opposite directions and pass at least at least two guide rollers (10, 11) located near the loop formation zone and mounted on at least two bearings (12, 13) supported by respective drive shafts to ensure that the belts (5, 6) are pressed against each other under by friction avaemyh drive shafts on the support, characterized in that it comprises means (14, 15, 21, 22) changing the shape of the envelope surface of the belts to ensure obtaining different tensioning force locally acting on the web or knitted fabric. 2. The device according to claim 1, characterized in that the means for changing the shape of the envelope surface of the tensioning belts are clamping means mounted on the supports (21, 22), which exert pressure on the belts with a local increase in their tension and, therefore, pressure on the knit, i.e. pulling force. 3. The device according to claim 1, characterized in that the means of changing the shape of the envelope surface of the tensioning belts increase the contact surface of at least one of the knitted belts. 4. The device according to claim 2 or 3, characterized in that at least one support (12, 13) is divided into several independent supports (12a-12d). 5. The device according to claims 2, 3 or 4, characterized in that the means for changing the shape of the envelope surface of the belts are formed by at least one elongated body (21, 22), which is parallel to the axis of the drive shaft, which is mounted on the support (12) between it and the belt (5), the length of which is equal to some part of the length of the needle beds and which is installed with the possibility of movement on the supports in the axial direction, as well as by means (17, 18, 23, 24) of bringing these bodies into motion in the axial direction, while these bodies move the belts away from the supports with a change in that m forms the envelope surface of the belts. 6. The device according to claim 5, characterized in that the elongated bodies (21, 22) are installed on the inner and / or outer side of the supports. 7. The device according to claim 5 or 6, characterized in that each elongated body (21, 22) is mounted on the worms (17, 18) between two nuts (19, 20) held rotatably, and the worms (17, 18 ) individually driven by engines FIG. 1 (23-26) with the provision of automatic movement of elongated bodies (21, 22) depending on the specific knitting zone. 8. The device according to claim 7, characterized in that the elongated bodies (21, 22) are rollers that rotate freely or unfree on worms. 9. The device according to one of claims 1 to 8, characterized in that grooves (30) are made on the outer surface of the belts. 10. The device according to claim 9, characterized in that the grooves (30) are parallel to the axis of the drive shafts. 11. The device according to claim 9, characterized in that the grooves have a spiral shape. 12. The device according to claim 9, characterized in that the belts have two systems of cross spiral grooves. 13. The device according to one of claims 1 to 12, characterized in that it comprises motors (14, 15) with an adjustable rotation speed, which drive the corresponding drive shafts (7, 8). 14. The device according to item 13, wherein the engines (14, 15) have two directions of rotation.