GB2032471A

GB2032471A - Double Twisting Machines

Info

Publication number: GB2032471A
Application number: GB7934502A
Authority: GB
Original assignee: Barmag Barmer Maschinenfabrik AG
Current assignee: Oerlikon Barmag AG
Priority date: 1978-10-04
Filing date: 1979-10-04
Publication date: 1980-05-08
Also published as: FR2438101B1; FR2438101A1; GB2032471B

Abstract

An injector (15) for grasping the yarn by suction and delivering it concentrically to the core of the spindle is situated in a yarn brake inserted of each double twist twisting spindle. The yarn brake insert (9) has a connecting coupling (17) for a compressed air pipe (18) with a system of ducts leading to the injector (15). Operation of the injector (15) also deactivates the yarn brake. <IMAGE>

Description

SPECIFICATION Double Twist Twisting Machine This invention relates to a double twist twisting machine having devices for pneumatically threading the yarn into the core of the individual twisting spindles, which spindles contain an injector for grasping the yarn by suction and conveying it concentrically to the core of the spindle.

Twisting machines of this type have already been disclosed, for example in German Auslegeschrift No. 25 41 690, German Patents Nos. 20 35 025 and 24 61 796, and Swiss Patent No. 296 61 7. It is also known to place a manually operated yarn gun at the yarn inlet (German Auslegeschrift No. 25 41 690).

According to the present invention there is provided a double twist twisting machine, comprising devices for pneumatically threading a yarn into the core of the individual twisting spindles, an injector for grasping the yarn by suction and delivering it concentrically to the core of the spindle, the injector being situated in each double twist twisting spindle, and a yarn brake insert having a connecting coupling for a compressed air pipe with a system of ducts leading to the injector, the injector being situated in the yarn brake insert of each double twist twisting spindle.

As is well known, the yarn brake insert can easily be removed from the bobbin carrier by a simple manipulation. The present invention therefore affords the advantage that the injector is very easy to adjust, service and clean.

The injector is advantageously made in two parts for this purpose, the yarn inlet part being fixed to the yarn brake insert while the yarn outlet part of the injector is displaceable in the direction of the spindle axis and can be fixed in any position. It is thereby possible to adjust the air consumption of the injector and the suction and transportion effect of the injector.

The adjustability of the injector is important for converting the machine to other yarns and yarn titres.

Reliable operation of the injector for threading the yarn depends among other things on ensuring that the supply of air will be uniformly distributed around the mouth of the yarn inlet tube. It is therefore advantageous to arrange an annular channel infront to the injector. This may be, for example, in the form of an annular cavity between an external jacket and an internal jacket of the yarn brake insert.

The connecting coupling and the annular channel of the injector are preferably situated substantially on a common plane normal to the axis of the spindle. Advantageously, the connecting channel between the connecting coupling and the annular channel'makes an angle of from 30 90 to the spindle axis. By this means only a very short system of ducts connects the injector to the -connecting coupling. This not only has manufacturing advantages but also advantages for the pneumatic system in that the pressure drop between the connecting coupling and the injector is very low and the supply duct provided for transmitting the static pressure for operating the brake may also be subjected to a high static pressure.

In an advantageous embodiment the yarn brake insert has an internal and an external jacket which together define a cavity. The external jacket is supported on the internal jacket and carries the connecting coupling for the air connection, the coupling being connected to the cavity. The injector is continuous with that end of the cavity which is adjacent to the spindle.

The supply of compressed air to each double twist twisting spindle may be provided from a compressed air duct extending along the machine, with branches leading to the individual spindles.

Alternatively, a unit travelling along the machine may be equipped with a compressed air supply system and a connecting pipe which can be adjusted to any connecting coupling of the yarn brake inserts.

If a central compressed air supply is provided, the problem of delivering the compressed air can be solved very simply and reliably by means of individual, manually operated hoses branching off the central pipe extending along the machine, and associated with individual double twist twisting spindles or groups of these spindles. These hoses can be fixed from time to time to the connecting coupling, for example by means of a bayonet lock.

In order to prevent accidental escape of compressed air, possibly due to carelessness, the ends of the hoses or adapters of the swivel arms are equipped with valves which automatically open when the hoses are connected to the connecting couplings and automatically close when the hoses are removed.

Alternatively, each double twist twisting spindle has associated with it a swivel arm which contains a compressed air duct and which is adapted to pivot about an axis parallel to the spindle axis and has an adapter at its free end for the connecting coupling of the yarn brake insert.

Central compressed air supply systems are particularly desirable on account of the fact that the connecting couplings for the hoses or swivel arms are readily accessible since they are attached laterally to the yarn brake units, above the edges of the sleeves.

For threading the yarn, the yarn brake situated in the yarn brake insert must either be by-passed or put out of action. In a preferred embodiment, the yarn brake is put out of action pneumatically, the pressure or vacuum for opening the brake being taken through a tap channel opening into- the region of high or lowpressure.

If the yarn brake insert isdesrgned so that sufficient space is available, the pneumatic pressure for opening the yarn brake is advantageously taken from the annular channel situated in front of the injector. In that case, if two yarn brakes are provided in a brake insert, the injector may be placed between the two brakes, and the pneumatic devices for opening the brake may be supplied from the supply pipe or the annular channel of the injector through a respective tap channel.

The yarn brake is advantageously in the form of a plate brake comprising two plates which make contact substantially in a plane of the path of the yarn, one plate being preferably fixed and the other pressed against the fixed plate by the adjustable force of a spring.

For pneumatic threading of the yarn, mechanical pneumatic devices may be provided which counteract the spring force of the movable disc and lift it from the fixed disc when the yarn is being threaded.

Instead of the pneumatic threading of yarn into the yarn brake described above, one or both brake plates can be provided with a recess outside the straight path of the yarn, which recess extends from the inlet of the yarn into the brake to the outlet of the yarn from the brake.

According to a preferred and very simple solution, an air channel bounded by the plates is worked into the brake housing which accommodates the two brake plates, this channel being placed in the plane of contact of the two plates.

All these solutions have the object of carrying the yarn in a circuitous plate round the yarn brake surface for the threading process so that when the yarn has been threaded it is automatically pulled between the brake plates due to the resulting tension in the yarn.

One particularly advantageous device for putting the yarn brake out of action when pneumatically threading the yarn comprises pneumatic cylinder and piston units which are preferably arranged on both sides of the path of the yarn and have a tappet rod attached to the piston and directed towards the movable brake plate. These cylinder and piston units are connected to the pneumatic conduit system which is accommodated in the yarn brake insert and leads to the injector, the connection being advantageously established by a tap channel which transmits the static pressure at the air inlet of the brake insert to the cylinder and piston units.

In another embodiment, pneumatic actuation of these cylinder and piston units is effected by connecting the cylinders into the conduit system with the inlet and outlet aperture shifted from each other in the axial direction of the cylinders, and arranging the cylinders so that the piston sweeps over the outlet aperture when it is moved out. This ensures that sufficient pressure is available in the cylinder to lift the movable brake plate and move it for a sufficient distance.

Pneumatic lifting of the movable brake plate may also be effected by constructing this movable plate in the form of a stepped piston having both its smaller and its larger circumferential piston surface moving with a sealing fit. The tap channel then leads into the cylinder chamber which is formed by the annular surface of the larger part of the stepped piston.

It is also possible to connect the movable brake disc with a pull rod to which a thrust piston is attached. The thrust piston is subjected to compressed air from a tap channel, whereby the movable brake surface is lifted from the fixed surface.

In the accompanying drawings: Fig. 1 is a diagrammatic sketch of a double twist twisting spindle having a yarn brake insert with injector, according to the invention; Fig. 2 shows an example of a yarn brake insert; Fig. 2a is a diagrammatic sketch of another embodiment, in which the injector is supplied with compressed air through an annular cavity between an external and internal jacket of the yarn brake insert; Fig. 3 shows a double twist twisting machine with a central compressed air supply for the injectors according to the invention; Fig. 4 shows another embodiment of the compressed air supply and four double twist twisting spindles; Fig. 5 is a section through an exemplary embodiment of a yarn brake; Fig. 6 is a sectional view of the embodiment of Fig. 5, taken at right angles to the section- of Fig.

5; Figs. 7 and 8 show brake inserts with devices for pneumatic threading; Figs. 9 and 10 show further constructional embodiments of the threading device.

Fig. 1 shows a double twist twisting spindle in which a bobbin 1 with a bobbin sleeve 2 is mounted on a bobbin carrier 3 with an enclosing guard. The bobbin carrier 3 is rotatably mounted on a spindle or rotor 5 in bearings 4 but secured against rotation by known devices such as magnets, for example, or by weights in the case of an obliquely placed or horizontal spindle. The spindle or rotor 5 with the yarn deflecting plate 6 and storage disc 7 are driven by whorls and drive belts. The yarn is drawn off the bobbin in known manner, first through the yarn inlet 8 and then through the yarn brake 10 which consists of a fixed brake plate 11 and a movable brake plate 12. The movable brake plate 12 is pushed against the fixed brake plate 11 by a spring 13 whose spring force can be adjusted by means of an adjustment screw 19 shown in Fig. 2. The yarn is then conducted through a yarn channel 14 and emerges through a storage disc to be carried round the bobbin as a ballooning yarn.

An injector 1 5 which is accommodated in the yarn brake insert is used for threading. In the embodiments illustrated here, the injector is situated behind the yarn brake. The injector is supplied with compressed air through a system of channels 1 6. The compressed air is delivered through a pipe 1 8 which is designed to be mounted on a coupling member 17 of the yarn brake insert and can be attached to it from time to time, e.g. by means of a bayonet lock (not shown here).

Details of the yarn brake insert 9 are illustrated in Fig. 2. It should be pointed out that it is only by way of example that the yarn brake insert 9 is illustrated as being equipped with a plate brake.

This brake consists of the fixed brake plate 11 having its brake surface in the plane in which the yarn passes through the yarn channel 14, and the movable brake plate 1 2 which is pushed against the fixed plate 1 1 by the pressure of the spring 13. The spring can be adjusted by turning the adjustment screw 1 9. Situated below the yarn brake 10 in the path of the yarn is the injector 1 5.

This injector is supplied with compressed air from the air supply pipe 18, in the present case a connecting hose, by way of the compressed air duct (air channel 16) and the annular channel 20 and distributor bores 21. The connecting hose (air supply pipe 18) shown in this particular example has a valve 22 which is closed by being urged against the coupling 1 7 of the yarn brake insert 9.

When the hose is introduced into the coupling 17, the valve 22 is pushed into its open position by a pin 25 fixed in the air channel 1 6. The injector is constructed according to well known principles.

The air expanding in the region of the mouth 26 causes a reduction in air pressure inside the yarn inlet tube (yarn channel 14), whereby suction is exerted on the yarn. The yarn is then pulled into the core of the spindle by the air current behind the opening 26 and is carried out of the yarn guiding channel of the storage disc 7.

As further illustrated in Fig. 2, the compressed air supply for the pneumatic cylinder and piston units which serve to lift the movable brake plate is connected parallel to the compressed air supply of the injector through a tap channel 36 which is branched off the channel system to the injector immediately behind the connecting coupling and ends behind the last cylinder and piston unit. This ensures that the cylinder and piston units are exposed to the static pressure prevailing at the inlet to the yarn brake insert, which static pressure, as is well known, is partly converted into flow energy in the course of its passage through the channel system leading to the injector.

The injector 1 5 is made in two parts. The part which is the upper part, viewed in the direction of travel of the yarn, and through which the air and yarn are supplied, is integrally connected with the yarn brake insert 9 while the lower part 27 is connected to this upper part by a screw connection 28 and axially displaceable in relation to it. The lower part can be fixed in any position in relation to the upper part so that it will not shift during operation of the machine. This locking of the lower part may be effected by, for example, a spring operated catch fixed to the lower part and engaging in a groove on the circumference of the upper part. Devices of this type are well known to the man skilled in the art and therefore not described in detail here.The yarn brake insert 9 with its insert member 29 is placed on the bobbin carrier 3 of Fig. 1 and held in position by O-rings 30 and sealed off in air tight manner. The yarn brake insert 9 can easily be removed from the bobbin carrier 3 by hand and the injector 1 5 adjusted at the same time. This is particularly important when production of the machine is to be changed over to other materials and other yarn titres.

Fig. 2a shows a yarn brake insert 37 which is a modification of the insert 9 of Fig. 2 and has a double jacket in the region of its external circumference. The external jacket 38 and internal jacket 39 together enclose an annular cavity 40 which substantially corresponds in its function to that of the concentric annular channel 20 (Fig. 2).

This cavity 40 is hermetically sealed off at the top, that is to say at the end where the yarn enters. At the other end, that is to say at the end where the injector is situated, this annular cavity 40 opens into the injector 1 5. The external jacket has the connecting coupling 1 7 as well as an opening for the passage of compressed air into the annular cavity. The external jacket 38 and internal jacket 39 may be supported against each other by ribs, cams or similar projections (not shown).

Fig. 3 is an elevational view of a double twist twisting machine corresponding to the standard DIN 63955. The machine has a central compressed air supply 31 with a compressed air duct 32 extending along the length of the machine. A hose attached in some suitable manner and controlled by hand serves to supply compressed air, each hose to one spindle field. In the last field, it can be seen that a swivel arm 33 can be pivoted about the vertical tap channel 34 so that, as shown in Fig. 4, it can be used to supply compressed air to one spindle at a time. To close the air channel of the swivel arm 33, the mounting of the arm 33 on the vertical tap channel 34 is so designed that the radial branch of the tap channel 34 is in alignment with the air channel 35 in the swivel arm 33 only when the swivel arm 33 firmly bears against the connecting coupling 1 7 of the yarn brake insert 9.The swivel arms 33 may have special adapters at their ends for an air-tight connection to the connecting couplings 1 7. The vertical tap channel is laid in the vertical mid-plane of the machine so that two swivel arms on the channel can supply four spindles.

Figs. 5 and 6 show a further embodiment of the spindle brake. It can be seen that the mechanical operating means are arranged on a normal plane of the path of the yarn in such a manner that they are situated on both sides of the yarn and thus lift the movable brake plate 12 on all sides from the fixed plate 11.

It should be mentioned that other forms of brakes could be used in the yarn brake insert 9, for example, brake cartridges or ball brakes.

Suitable methods of putting such brakes out of action during pneumatic threading of the yarn are already known. The proposed way of putting the brakes out of action by pneumatic means has the further advantage that a plurality of brakes, in particular plate brakes, may be arranged one behind the other in the direction of travel of the yarn and put out of action pneumatically.

Fig. 7 shows a modification of the embodiment of Fig. 2. Parts identical to those of Fig. 2 have therefore been marked by identical reference numerals.

Figs. 7 and 8 represent brake inserts with devices for pneumatic threading. The difference between Figs. 7 and 8 on the one hand and the embodiments described with reference to the earlier Figures lies in the fact that the injector 1 5 is situated substantially on or close to the normal plane in which the connecting coupling 1 7 for the air supply pipe 1 8 is situated. The connecting channel 47 between the connecting coupling 1 7 and the annular channel 20 makes an angle of more than 450 with the axis of the spindle. The annular channel is preferably situated at the same axial height as the connecting coupling.

In the embodiment according to Fig. 7, the tap channel 36 which serves to supply a static pressure to the cylinder and piston units 41 which lift the movable brake plate 12 from the fixed brake plate 11 branches directly off the annular channel 20. The cylinder and piston units are therefore subjected to the static pressure prevailing in the annular channel, so that the pistons 42 with their rods 43 lift the movable plate 12 from the fixed plate 1 After the yarn has been threaded, the springs 44 return the piston with rod so that the brake surface between the plates is again free.

Fig. 8 shows how the pressure for opening the brake is taken from the thread guide tube through channel 46 which opens at the front end 26 of the injector 15, where a vacuum prevails. The movable brake plate 12 is constructed as a piston moving in the cylinder chamber 45. The vacuum therefore causes the movable brake plate 12 to be lifted from the fixed brake plate 11 against the force of the spring 13 when the yarn is being threaded.

In cases where two yarns brakes are used in a brake insert, as is necessary for certain purposes, the connecting coupling and the injector are preferably situated between the two brakes, viewed in the axial direction, and a tap channel for transmitting the static pressure then branches off in both axial directions from the connecting channel between the connecting coupling and the injector or from the annular channel, or two tap channels are provided, leading from the pneumatic opening devices for the two brakes to the yarn guide tube. For the sake of clarity, it should be mentioned that a static excess pressure for opening the brake may also be tapped off at suitable points of the yarn guide tube.

In the simplest case, opening of the plate brakes illustrated in the examples may also be effected by excess pressure on the brake surface if a vent aperture is provided at the back of the movable brake plate.

Figs. 9 and 10 also illustrate modified embodiments, and substantially the same reference numerals have again been used.

In Fig. 9, the movable brake plate 12 is a stepped piston comprising a smaller piston part 51 and a larger piston part 52. Both piston parts are guided wtih a sealing fit so that an annular chamber 53 is formed, which is supplied with compressed air from the annular channel 20 through the tap channel 36 when the yarn is being threaded pneumatically by means of the injector 1 5. The pressure in the annular chamber 53 lifts the movable brake plate 12 from the fixed brake plate 11 for the duration of the threading process.

In Fig. 10, the movable brake plate 12 is equipped with a pull rod 54 and thrust piston 55.

The tap channel 36 in this case opens into the cylinder chamber 56 in which the thrust piston 55 is displaceable. It should be noted that in the embodiment shown in Fig. 10, the movable brake plate 12 is pressed against the fixed brake plate 11 by a spring 57 acting on the thrust piston 55.

The spring 57 is readily accessibie by means of the end screw 58 and its spring force is adjustable. The end screw 58 has a vent aperture 59.

Claims

1. A double twist twisting machine, comprising devices for pneumatically threading a yarn into the core of the individual twisting spindles, an injector for grasping the yarn by suction and delivering it concentrically to the core of the spindle, the injector being situated in each double twist twisting spindle, and a yarn brake insert having a connecting coupling for a compressed air pipe with a system of ducts leading to the injector, the injector being situated in the yarn brake insert of each double twist twisting spindle.

2. A machine according to Claim 1, wherein an annular channel which is concentric to the core of the spindle is situated in front of the injector.

3. A machine according to Claim 1, wherein the connecting coupling and an annular channel of the injector are situated substantially on a common plane normal to the axis of the spindle.

4. A machine according to Claim 3, wherein a connecting channel between the connecting coupling and the annular channel makes an angle of from 900 to 300 to the spindle axis.

5. A machine according to any preceding Claim, wherein the yarn brake insert has an internal jacket and an external jacket which together define a cavity, the external jacket being supported on the internal jacket and carrying the connecting coupling for the air connection, the coupling being connected to the cavity, and the injector being continuous with that end of the cavity which is adjacent to the spindle.

6. A machine according to any preceding Claim, comprising a central compressed air supply communicating with a pipe extending along the machine, from which pipe ducts branch off to each double twist twisting spindle or groups of such spindles.

7. A machine according to Claim 6, wherein the compressed air is supplied by means of a hose which is branched off the pipe and is designed to be inserted by hand into the connecting coupling of the yarn brake insert.

8. A machine according to Claim 6, wherein the compressed air is supplied by means of a swivel arm on a swivel pin parallel to the spindle axis, having an adapter at its free end for the connecting coupling of the yarn brake insert.

9. A machine according to Claim 7, wherein the hose can be firmly connected from time to time to a connecting coupling.

10. A machine according to Claim 9, wherein the connecting coupling and hose are connectable together by a bayonet lock.

11. A machine according to any of Claims 7 to 10, wherein a valve is arranged on the hose or swivel arm, which valve can be opened by placing the adapter on the connecting coupling of the yarn brake insert.

12. A machine according to any one of Claims 1 to 4, wherein compressed air is supplied by means of a unit displaceable along the front of the machine, associated with compressed air supply devices which can be adapted to the connecting coupling of each yarn brake insert.

1 3. A machine according to any preceding Claim comprising devices for pneumatically threading the yarn by means of an air jet produced in the central thread guiding tube, pneumatic devices being provided for opening the yarn brake.

14. A machine according to Claim 13, wherein the pressure or vacuum for operating the pneumatic devices for opening the yarn brake is taken from the thread guiding tube.

1 5. A machine according to Claim 14, wherein a tap channel opens into the thread guiding tube in front of the brake or brakes, viewed in the direction of threading.

16. A machine according to Claim 14 or Claim 15, wherein a tap channel opens'intro the thread guiding tube in a region of static vacuum.

17. A machine according to Claim 14 or Claim 15, wherein a tap channel opens into the thread guiding tube in a region of static excess pressure.

18. A machine according to any one of Claims 13 to 17, as dependent directly or indirectly on Claim 2 or 3, wherein the devices for opening the yarn brake are connected to the annular channel of the injector.

19. A machine according to any preceding Claim, wherein the yarn brake insert contains two yarn brakes and the connecting coupling and injector are situated between the yarn brakes viewed in the axial direction.

20. A machine according to Claim 19, as dependent on Claim 18, wherein from the conduit to the injector or its annular duct, tap channels branch in both directions to the devices for opening the brake.

21. A machine according to any preceding Claim wherein the yarn brake comprises a fixed brake surface and a movable brake plate which is pressed against the fixed brake surface by an energizing device, the brake plate being liftable from the fixed brake surface by a cylinder and piston unit which is connected to the system of ducts leading to the injector and which has a tappet rod directed towards the movable brake plate.

22. A machine according to any one of Claims 1 to 20, wherein the yarn brake comprises a fixed brake surface and a movable brake plate which is pushed against the fixed brake surface by an energizing device, the movable brake plate being a stepped piston having both its smaller and larger part movable with a sealing fit, a tap channel leading into a cylinder chamber which is formed by the annular surface of the larger part of the stepped piston.

23. A machine spindle according to any one of Claims 1 to 20, wherein the yarn brake comprises a fixed brake surface and a movable brake plate which is pushed against the fixed brake surface by an energizing device, the movable brake plate being connected to a thrust piston by a tie rod, which piston is subjected to the pressure of compressed air through a tap channel so that the movable part is lifted from the fixed brake surface.

24. A machine according to any one of Claims 21 to 23 comprising cylinder and piston units arranged on both sides of the path of the yarn, the rods of the pistons being directed against the movable brake plate while the cylinders are connected to the system of ducts leading to the injector.

25. A machine according to Claim 24 wherein the cylinders are enclosed in a system of ducts leading to the injector, and the outlet opening of each cylinder from this system of ducts is displaced from the inlet opening in the axial direction of the cylinder so that the piston sweeps over the outlet opening when it is subjected to the pressure of the compressed air.

26. A machine according to Claim 24 or 25, wherein the channel leading to the cylinder and piston units is in the form of a tap channel closed at one end, branched off the system of compressed air ducts (16) leading to the injector shortly behind the connecting coupling.

27. A machine according to any preceding Claim, wherein the injector is made in two parts, a yarn inlet part of the injector being fixed to the yarn brake insert and a yarn outlet part being displaceable in the direction of the spindle axis.

28. A machine according to Claim 27, wherein the yarn outlet part of the injector is secured against rotation relative to the yarn inlet part by means of a recess on one part engaging with a circumferential notch on the other part.

29. A double twist twisting machine, substantially as herein described with reference to any one of the embodiments shown in the accompanying drawings.