WO2010028513A1

WO2010028513A1 - Drawing system for a knitting machine

Info

Publication number: WO2010028513A1
Application number: PCT/CH2009/000264
Authority: WO
Inventors: Hans Stahlecker
Original assignee: Rotorcraft Ag; Sipra Patententwicklungs- Und Beteiligungsgesellschaft Mbh
Priority date: 2008-09-09
Filing date: 2009-07-24
Publication date: 2010-03-18
Also published as: CH699521A2

Abstract

The invention relates to a drawing system, comprising lower cylinders (7) which on one side are fastened to a housing plate (2) and freely protrude therefrom. The lower cylinders (7) comprise shafts (71) which extend through the housing plate (2) and can be motor-driven by drive means (72) disposed at a back (22) of the housing plate (2). A sealing gap (19) is present between an end section (70) of each lower cylinder (7) that faces the housing plate (2) and a flange (20) connected to the housing plate (2). The drive means (72) disposed at the back (22) of the housing plate (2) is provided with a largely air-tight cover (100). The housing plate (2) has at least one through-hole (27) in the region of each sealing gap (19). Overpressure can be built in the space (102) enclosed in a substantially air-tight manner by the back (22) of the housing plate (2) and the cover (100).

Description

Drafting system for a knitting machine

The invention relates to a drafting system for a knitting machine according to the preamble of patent claim 1.

In the past, it has been proposed several times to produce knitwear directly from staple fibers or from a roving. Due to the entanglement of a substantially untwisted fiber structure with approximately parallel aligned fibers, the fabric produced has a very 'soft touch' and has a very high wearing comfort. The knitwear can also be produced very inexpensively, since the intermediate stages of the classic yarn production, namely yarn formation, winding and possibly rewinding omitted. The untwisted fiber structure also has a certain longitudinal elasticity, as a result of which directional changes in the thread guide in the knitting machine are better tolerated and thread breaks are less likely to occur.

For example, in US-A-3,877,254 it is proposed to supply staple fibers to the needles of a knitting machine. The device described there is described using the example of a circular knitting machine. The staple fibers aligned in parallel via brushes are grasped by a hooked wheel to form a loop, combed out and transported to the needles of the circular knitting machine, from which they are knitted into a knitted fabric. The binding points within the mesh should give the knit the required strength. It is also mentioned that in addition an auxiliary thread from a yarn can be mitverstrickt.

In WO 2004/079068 a circular knitting machine is proposed, the knitting points of which instead of each knitting point associated, withdrawn from a yarn tube, finished yarn presented by an upstream drafting distorted fiber structure. The drafting system is a three- or more-cylinder drafting system with twin aprons and output pressure roller pair, as is also known from ring spinning machines known from the prior art for yarn production. The roving is withdrawn from a jug or from a roving, fed into the drafting and warped in the drafting to the desired extent. The warped fiber strand can be fed directly to the needle of a knitting point, which is arranged after the output pressure roller pair. For reasons of space, the drafting arrangements are in groups, for example three, over the circumference of the needle cylinder of the circular knitting machine. arranged distributed. Each draft group consists of a number of linearly adjacent drafting systems, which are equipped with a common drive for the driven drafting components. The driven drafting components each comprise at least one continuous cylinder. In order to avoid all too strong changes of direction in the thread progression between the drafting device groups and the associated knitting points, active knitting points alternate with so-called dead zones or areas on the needle cylinder in which the circular knitting machine has no knitting points or no knitting points used during knitting. As a result, only about half of the existing knitting stations can be used in a large circular knitting machine of known design.

The fact that only a part of the knitting points provided in a large circular knitting machine is usable in the processing of a distorted in a drafting fiber structure represents a major drawback of this otherwise attractive technology. An increase in the diameter of the needle cylinder represents a technological step backwards and comes for structural reasons and because of space problems in many cases out of the question. In addition, the grouped drafting systems are not very easy to maintain.

In the international PCT application no. PCT / CH 2008/000340, therefore, the Applicant proposes a drafting device whose sub-cylinders each have axles which are fixed on one side to a base plate and protrude freely therefrom. The drive of the sub-cylinder arranged in such a way takes place via electric motors. The compact design of this drafting contributes that also arranged on the base plate electric motors have rotors which extend through the base plate and are connected on the back of the base plate with drive pinion, via which the sub-cylinder can be driven. In this novel, space-saving design variant of the drafting system, the drive function and the delay function are consistently separated. The drive means arranged on the rear side of the base plate are protected by a covering from impurities due to fiber fly and abrasion.

In the lower cylinders arranged on the base plate, there is an annular circumferential sealing gap between the end section of the rotating cylinder jacket facing the base plate and the flange connected to the base plate. During operation of the drafting system there is a certain risk that fibers, abrasion or dirt accumulate in this sealing gap. Such deposits can cause rotation obstruct the cylinder and lead to increased energy consumption, even to an overload of the drive motor. In the worst case, the impurities can even lead to a blockage of the cylinder.

Object of the present invention is therefore to improve such a compact design drafting arrangement with flying on a base plate arranged lower cylinders to the effect that the risk of contamination of the sealing gaps of the cylinder is eliminated. The modification should not affect the compact design of the drafting system; It should be simple and inexpensive to carry out.

These objects are achieved according to the invention by a drafting system for a knitting machine with the features listed in claim 1. Further developments and advantageous and preferred embodiments of the invention are the subject of the dependent claims.

The drafting system according to the invention has sub-cylinders, which are fastened on one side to a housing plate and protrude freely therefrom. The sub-cylinders have axes that protrude through the housing plate and are driven by motor arranged on a rear side of the housing plate drive means. Between one of the housing plate facing the end portion of each sub-cylinder and a projecting from the housing plate flange is an annular circumferential sealing gap. The arranged on the back of the housing plate drive means are provided with a largely airtight cover. The housing plate is provided in the region of each sealing gap with at least one through hole. In the from the back of the housing plate and the cover substantially airtight space enclosed an overpressure can be built up.

The through holes make it possible to guide compressed air into the region of the annular circumferential sealing gaps from the rear side of the housing plate. The blown out as a result of a slight overpressure through the through holes air flow prevents fibers, abrasion or dirt particles begin in the region of the sealing gaps. The structurally very simple measure is effective and works reliably even at very low air flows. It is feasible with little effort and very inexpensive. For the generated during operation, pointing away from the sealing gap air flow prove through holes with a diameter of 1 mm to 4 mm as appropriate. With these diameters, the compressed air is not pressed like a nozzle into a small section of the sealing gap, but rather covers the entire ring-shaped sealing gap over a relatively large area.

To generate the overpressure in the space enclosed by the housing plate and cover, the housing plate or cover is provided with ports and channels for connection to a source of compressed air.

For the compact design of the drafting system, it proves to be expedient if the drive motors are arranged on the same side as the lower cylinder. On the back of the housing plate are only the drive pinion and possibly drive belt and the like, all of which have a flat design. In this way, the height of the space enclosed by the housing plate and the cover space can be kept low.

In one embodiment variant of the drafting system according to the invention, at least two sub-cylinders are arranged on the housing plate and interact with corresponding pressure rollers. The sub-cylinders are driven by arranged on the back of the housing plate drive means. The sealing gaps between their housing areas facing the end portions and the associated mounting flange are kept free by the inventively provided through holes and pointing away from the sealing gaps air flows of fibers, abrasion and impurities.

The drafting system may have different default elements. Conveniently, however, it comprises a main drafting zone with a pair of aprons. The distortion of a fiber dressing between cooperating straps is well proven and very effective.

A very expedient embodiment of the drafting system is designed as a three-cylinder drafting system. Such drafting systems have a very compact design and are equipped with an input sub-cylinder and an associated input pressure roller, with a belt lower cylinder and a belt pressure roller and with an output lower cylinder and an associated output pressure roller. The

Drawframe thus has a Vorverzugszone and a main drafting zone. This allows a very effective and uniform distortion of a supplied fiber structure.

For easy and quick replacement of a drafting system whose housing plate is advantageously provided with a quick-release device, by means of which it can be fastened in the vicinity of a knitting point on a frame part of a knitting machine. When installing the drafting system is automatically made a connection to a compressed air source and with an electrical supply. The electrical supply and the compressed air supply thereby rest on the correspondingly formed frame of the knitting machine and can be tapped if necessary.

For use in known knitting machines with, for example, 48 or 96 knitting points, the drafting device has a height, measured in relation to the extent of the axes of the lower cylinders, which is 50 mm to 100 mm.

For an even more compact arrangement in a knitting machine, the drafting device can be designed for the simultaneous distortion of at least two slivers running parallel next to each other.

Knitting machines equipped with a drafting device according to the invention allow an immediate entanglement of a warp-knit fiber composite made from a roving (V) into a knitted fabric. The inventive design of the drafting system with a forced air guide in the region of the sealing gaps of the lower cylinder prevents downtime due to excessive contamination of the rotating components by fiber fly, abrasion or other impurities.

In principle, flat knitting machines can also be equipped with the above-described drafting systems. However, the drafting systems are optimized for use with circular knitting machines. It may be provided for reasons of space that each drafting system is assigned two or more adjacent knitting points.

Further advantages will become apparent from the following description of an embodiment of the invention, with reference to the schematic drawings. It shows in not to scale representation: Fig. 1 is an overall perspective view of a Sireckwerk according to the invention;

FIG. 2 shows a plan view of the rear side of a housing plate of the drafting system; FIG. and

Fig. 3 is a sectional view of a portion of the housing plate with rear-mounted cover and front abragendem sub-cylinder.

Fig. 1 shows a perspective view of a total provided with the reference numeral 1 drafting system, as used for example in circular knitting machines. The illustration shows the drafting system 1 from the perspective of the output of the drafting system. In the drafting system 1 shown, for example, is in particular a so-called three-cylinder drafting system, which each have a Eingangsun- terzylinder 3, a Riemchenunterzylinder 5 and an output lower cylinder 7, which are mounted on one side of a housing plate 2 and cantilever protrude from the front side 21 , The sub-cylinders 3, 5, 7 are each associated with pressure rollers, wherein an input pressure roller with 4, a Riemchendruckwalze with 6 and an output pressure roller is provided with the reference numeral δ. The input pressure roller 4 and the belt pressure roller 6 are arranged and supported on a separate mounting plate not shown in detail, which is connected via a tension spring with the housing plate 2. The tension spring extends between a protruding from the housing plate abutment and a pressure pin, which is provided on the mounting plate and is loaded by a rotatably mounted on the housing plate 2 clamping eccentric. As a result, the input pressure roller 4 and the belt pressure roller 6 are pressed against the input sub-cylinder 3 and the apron sub-cylinder 5, respectively. The bias is adjustable via the clamping eccentric. The output pressure roller 8 is mounted in a relation to the housing plate 2 freely movable bracket. The holder is loaded by a leaf spring, one end of which is fastened to a mounting projection of the housing plate 2. The output pressure roller 8 is inserted into the holder only and can be easily removed by lifting the output pressure roller 8 from the output lower cylinder 7 against the biasing force of the leaf spring.

The sub-cylinders 3, 5, and 7 are driven by electric drive motors 13, 14, which are also attached to the housing plate 2 and project freely in the vicinity of the lower cylinders 3, 5, 7 thereof. The electric motors 13, 14 are preferably Asynchronous motors, which are controlled by frequency conversion. The drive means for the sub-cylinders 3, 5, 7 are arranged on the back of the housing plate 2 and protected by a cover 100 against fiber fly, abrasion and contamination. The cover 100 consists of a largely airtight material and is also substantially airtight connected to the housing plate 2. Fig. 1 also shows a quick-release device 101, by means of which the drafting 1 is very easy and quick to mount the frame of a circular knitting machine.

The three-cylinder drafting system 1 is designed for the delay of roving and has a Vorverzugszone 11 and a main drafting zone 12. The Vorverzugszone extends from the nip of the input lower cylinder 3 with the input pressure roller 4 to the combination Riemchenunterzylinder 5 and Riemchendruckwalze 6. The main draft zone 12 extends between the combination Riemchenunterzylinder 5, Riemchendruckwalze and the output lower cylinder 7 with the associated output pressure roller 8. The main delay occurs by means of a pair of straps which comprises a top apron 9 guided over the belt pressure roller 6 and a bottom apron 10 guided over the belt bottom cylinder 5. The drafting system 1 has a very compact design and has, for example, over the longitudinal extent of the lower cylinder measured height of only about 50 mm to about 100 mm.

2 shows a plan view of the rear side 22 of the housing plate 2, on which the actual drive means for the sub-cylinders 3, 5, 7 are arranged. The cover, which is intended to protect the components from contamination, has been removed for this purpose. The rotors of the electric motors protrude through the housing plate 2 and carry there driving crest 15, 16. The lower cylinder 3, 5, 7 have axes 31, 51, 71, which led through the housing plate 2 and on the back 22 of the housing plate 2 with Drive gears 32, 52, 72 are equipped. Toothed belts 17, 18 connect the drive pinions 15, 16 of the electric motors with the drive gears 32, 52, 72 of the sub-cylinders. The input sub-cylinder and the belt lower cylinder are driven by the same drive motor. The difference in the peripheral speeds of the two, the Vorverzugszone limiting lower cylinder results from the different diameters of the drive gears 32, 52. The diameter of the sub-cylinders are dimensioned such that the pre-distortion is for example about 1.2 to 1.4. The output sub-cylinder is driven by its own electric motor and has a much larger peripheral speed than the other two sub-cylinders. The difference in speed between the double aprons and the output lower cylinder agrees the draft of the roving, which may for example have a factor of 25 to 100. The fiber bundle, which is warped to the desired extent, is output at a delivery clamping line of the delivery roller pair and can be further processed directly. In Fig. 2 are still through holes 23, 25, 27 indicated, which are each arranged in the vicinity of the drive gears 32, 52, 72, and whose function will be explained in more detail below.

FIG. 3 shows, in a partially sectioned illustration, a section of the drafting system according to FIG. 1, which shows the starting lower cylinder 7 mounted in a flying manner on the housing plate 2. The ratios explained on the basis of the output lower cylinder 7 apply analogously to the input lower cylinder and the lower apron cylinder. For reasons of clarity, the illustration of the output pressure cylinder cooperating with the output lower cylinder 7 has been dispensed with in FIG. The output lower cylinder 7 has a cylinder jacket 70 which is non-rotatably connected to an axis 71. The axis 71 passes through an outer ring 73 and is on rolling elements 74, usually

Steel balls, stored. The outer ring 73 is mounted in a protruding from the housing plate 2 flange 20, for example, pressed. The flange 20 may be mounted on the front side 21 of the housing plate 2, but it may also be formed integrally with the housing plate 2. The axis 71 of the output lower cylinder 7 projects beyond the rear side 22 of the housing plate and carries a drive gear 72. The cover of the components arranged on the rear side 22 of the housing plate 2 is again provided with the reference numeral 100. The space enclosed by the rear side 22 of the housing plate 2 and the cover 100 bears the reference numeral 102.

Between the protruding from the front side 21 of the housing plate 2 flange 20 and the cylinder jacket 70 there is an annular circumferential sealing gap 19, which ensures an unobstructed rotation of the rotatably connected to the driven axis 71 cylinder jacket 70. In the vicinity of the drive gear 72, the housing plate 2 has at least one through-bore 27, which creates a connection between the space 102, which is substantially airtightly enclosed by the rear side 22 of the housing plate 2 and the cover 100, and the annular sealing gap 19. The through hole has a diameter of about 1 mm to about 4 mm.

In operation, there is the risk that fibers, abrasion and impurities enter the annular sealing gap 19, which can impair the rotation of the cylinder jacket 70. In order to prevent this, in which of the cover 100 and the return page 22 of the housing plate 2 enclosed space generates an overpressure. For this purpose, a compressed air source is connected, which supplies the necessary air pressure. Preferably, the connection to the compressed air source via corresponding connections, which is provided on the housing plate 2 or on the cover 100. For example, the compressed air connection is made automatically when the drafting system is mounted on the frame of the circular knitting machine. With appropriate equipment of the frame of the circular knitting machine so the compressed air connection can be made simultaneously and provided the electrical supply for the electric motors. By the pressure prevailing in the enclosed space 102, the compressed air is blown through the through hole 27 in the direction of the annular sealing gap 19. The resulting air flow prevents fibers, abrasion and impurities from entering the sealing gap 19. In order to keep the sealing gap 19 clear of fiber fly, abrasion and contamination, a relatively low air flow is sufficient.

The invention has been described using the example of a three-cylinder drafting system for the delay of Flyerlunte. Flyerlunte has a certain amount of rotation to give it the necessary transport strength. This rotation must first be resolved in the pre-draft zone before the fiber strand in the main draft zone is warped to the desired fineness. For the processing and the delay of conveyor belts that have no rotation, the drafting can also have a simpler structure and be formed without Vorverzugszone. It can also be provided that the drafting device is designed for the simultaneous delay of two or more, parallel fiber assemblies supplied.

Claims

claims

1. drafting system for a knitting machine with lower cylinders (3, 5, 7), which are fastened on one side to a housing plate (2) and protrude freely therefrom, whereby axes (31, 51, 71) of the sub-cylinders (3, 5, 7) protrude through the housing plate (2) and on a rear side (22) of the housing plate (2) arranged drive means (15, 16, 32, 52, 72, 17, 18) are motor driven, between one of the housing plate (2) facing end portion an annular circumferential sealing gap (19) of each lower cylinder (3, 5, 7) and a flange (20) projecting from the housing plate (2) and the drive means (15, 16) arranged on the rear side (22) of the housing plate (2) , 32, 52, 72, 17, 18) are provided with a largely airtight cover (100), characterized in that the housing plate (2) in the region of each sealing gap (19) with at least one through hole

(27), and in which from the back (22) of the housing plate (2) and the cover (100) substantially airtight space enclosed (102), an overpressure is buildable.

2. drafting system according to claim 1, characterized in that the through holes (27) have a diameter which is 1 mm to 4 mm.

3. drafting system according to claim 1 or 2, characterized in that the housing plate (2) or the cover (100) is equipped with terminals and channels for connection to a compressed air source.

4. drafting system according to one of the preceding claims, characterized in that the drive motors (13, 14) for the lower cylinder (3, 5, 7) protrude on the side of the lower cylinder of the housing plate (2).

5. drafting system according to one of the preceding claims, characterized in that on the housing plate (2) at least two sub-cylinders are arranged, which cooperate with corresponding pressure rollers.

6. drafting system according to claim 5, characterized in that it comprises a main drafting zone (12) with a pair of straps (9, 10).

7. Drawframe according to claim 6, characterized in that it as a Dreizylin- derstreckwerk (1) with an input lower cylinder (3) and an associated input pressure roller (4), with a Riemchenunterzylinder (5) and a Riemchen- pressure roller (6) and an output sub-cylinder (7) and an associated one

Output pressure roller (8) is formed.

8. drafting system according to one of the preceding claims, characterized in that the housing plate (2) with a quick-clamping device (101) is provided, via which they in the vicinity of a knitting point on a frame part of a

Knitting machine can be fastened, whereby automatically a connection with a compressed air source and with an electrical supply can be created.

9. drafting system according to one of the preceding claims, characterized in that it has a relative to the extension of the axes of the sub-cylinders (3, 5, 7) measured height, which is 50 mm to 100 mm.

10. Drafting system according to one of the preceding claims, that it is formed for the simultaneous delay of at least two parallel juxtaposed Faserbän- the.

11. Knitting machine for knitting of a made of a roving (V), warped fiber structure characterized by a drafting system (1) according to any one of claims 1-11.

12. Knitting machine according to claim 11, characterized in that it is a circular knitting machine.

13. Knitting machine according to claim 11 or 12, characterized in that each one drafting system is associated with two or more adjacent knitting points.