EP1526196A2

EP1526196A2 - A thread heating device

Info

Publication number: EP1526196A2
Application number: EP03024172A
Authority: EP
Inventors: Matteo Castiglioni; Urs Meyer; Robin Schwab; Hans Hunold; Christian Widmer
Original assignee: Maschinenfabrik Rieter AG
Current assignee: Maschinenfabrik Rieter AG
Priority date: 2003-10-20
Filing date: 2003-10-20
Publication date: 2005-04-27
Also published as: WO2005038107A1; CN1898424A; EP1526196A3

Abstract

A false twist texturing machine is modified to enable it to operate at very high revolutions (e.g. above 20,000RPM), i.e. processing rates with high linear threadline speeds (above 2000 M/Min). The friction disc stack is provided with a drive motor for each spindle shaft. For safety at high RPMs, the stack is encased in a protective housing which can absorb energy of flying parts in the event of breakage. Heat is supplied to the thread by non-contact heating (convection and/ or radiation) in an insulated space, the thread preferably being guided through the heated space by positively driven godet units. The thread path is so arranged that positive forwarding elements are provided at each diverting location, so that no passive guides or feeding nips are required. A special start-up procedure enables establishment of a stable threadline at relatively slow processing speed followed by acceleration to the set operating speed.

Description

The invention relates to improvements in thread processing machines, especially machines involving thread treatment by false twisting and/or heating the thread. Such machines are used for texturing thread. The invention also relates to units (modules), assemblies and components for use in machines according to the invention.

Terminology/Definitions:

In this specification, the term "texturing" is synonymous with the term "texturising" and the term "thread" is synonymous with the term "yarn".
The term "filament" refers to a man-made (chemical or synthetic) fibre usually in the form of a continuous body of polymer having a length so much greater than the filament diameter that the filament can for many purposes be considered "endless".
A "thread" ("yarn") can comprise a monofilament, but for texturing by means of the well-known false twist technology a "multifilament" thread is required.

State of the Art:

The following false twist texturing devices and arrangements are known from the patent literature:
i) thread path substantially in the form of an inverted "U" with at least one heater in the form of a godet and with a winder on one vertical leg of the path - see FR 2736937 of ICBT Roanne and US 6609277 of Retech;
ii) "on-line" texturing - see US 5724802 (Fig. 3) of UMIST;
iii) all active processing elements arranged on a vertical stretch of the thread path - see, for example, EP 332227, EP 442368 and US 4567721 of Teijin;
iv) "heating boxes" in place of the more conventional contact heaters - see for example US 3015872 of British Nylon Spinners and EP 626474 of Temco;
v) hollow rollers driven by a motor disposed within the roller body - see DE 3943560 of Zinser;
vi) enclosures (for guiding air circulation) around twisting spindles - see US 4803834 of FAG Kugelfischer;
vii) elastic mountings for the spindle shafts of friction disc stacks - see GB 2058157 of Barmag;
viii) the use of brushless motors to drive stacks of friction discs - see EP 1149941 of Teijin Seiki, and
ix) active cooling systems based on supply of a closely controlled quantity of liquid to the thread - see WO 01/38620 of Maschinenfabrik Rieter AG.
Despite these wide-ranging proposals, the industry still lacks a machine concept suitable for high speed operation, for example at linear threadline speeds above 1500 m/min. and/or rates of revolution of the twisting spindle above 20,000 RPM.

The invention:

The specification discloses several inventive aspects directed to the common goal of high speed texturing.
In a first aspect, the invention provides a thread heating device comprising a heat insulating enclosure, heating means for supplying heat to the space within the enclosure and at least one rotary thread guiding means disposed within the enclosure. The guiding means may have a cylindrical surface adapted to receive thread wraps. The cylindrical surface may be positively rotated by suitable drive means which are preferably also located within the enclosure, in fact preferably within the cylindrical guide surface. This aspect of the invention also provides a galette or godet unit comprising a hollow body having a cylindrical surface to receive at least one thread wrap, a bearing structure and a drive motor, the drive motor being disposed within the hollow body.
In a second aspect, the invention provides a device for generating false twist comprising a plurality of spindles each mounted on a support means for rotation about the longitudinal spindle axis and each adapted to carry a plurality of discs, a plurality of electric drive motors being associated individually with respective spindles. This aspect of the invention also provides a spindle module for use in a twisting device comprising a disc support shaft and an electric drive motor, the drive motor being directly coupled to the shaft.
In a third aspect, the invention provides a high speed twist generating unit comprising a friction disc stack with a drive adapted to rotate the discs at high speed, for example above 20,000 RPM. A casing is provided to absorb impact energy in the event of a failure of a rotating part in use.
In a fourth aspect, the invention provides preferred machine layouts. In one example, a thread processing machine comprises a support structure and thread processing elements carried by the support structure at respective locations spaced along a predetermined thread path which leads to a winding device, the thread path being so arranged that the thread is passed from each processing element to the next and finally to the winding unit without intervening passive guiding means and/or feed nips. Active processing elements may be disposed at positions along the yarn path at which the thread is to be diverted from a straight line, each such processing element taking up thread along a line aligned with the upstream portion of the thread path and delivering thread along a line aligned with the downstream portion of the thread path.
Further, the invention relates to a procedure for starting up a high-speed thread processing machine comprising thread processing elements and a winder. An additional take-up can be arranged to receive thread processed at relatively low speed and a control means may be provided to transfer the thread to the winder when the machine is operating at a predetermined minimum speed.
Preferably, all individual motors involved in driving spindle, godets, and winding unit, as well as all heating units are individually driven and speed controlled. All heating means can be individually driven and temperature controlled.
This can be done by means of a control system, employing suitable sensors (for example speed, temperature, thread tension), through suitable drives, according to predetermined settings and/or real time process controls.
One texturing position should be able to start, run at it's own setting and stop independently any other(s).
The invention will be further described with reference to embodiments illustrated by way of example in the accompanying drawings, in which:

Fig. 1: shows a schematic view in elevation of a texturing position in accordance with this invention;
Fig. 2: a schematic perspective view of a texturing module based on the principles shown in Fig. 1;
Fig. 3: a schematic view in perspective, viewed from the front, of a heater module suitable for use in a machine as shown in Fig. 1;
Fig. 4: a schematic perspective, viewed from the side, of an assembly for use in a module as shown in Fig. 3, one component being partially cut away to illustrate other components located within it;
Fig. 5: a schematic perspective of a friction disc assembly suitable for use in a false twist texturing machine, especially a machine as shown in Fig. 1;
Fig. 6: a schematic exploded drawing of a single motor/spindle shaft module suitable for use in the assembly shown in Fig. 5, Fig. 6A showing a detail of a possible modification;
Fig. 7: a schematic circuit diagram of an electrical control system suitable for a texturing position as shown in Fig.1 and/or 2, and
Fig. 8: a diagram for use in explanation of a start/stop procedure suitable for a high speed machine.

In the following text, the expression "texturing position" refers to a group of thread processing, guiding and forwarding elements mounted on suitable support structure and configured on a suitable thread path so that a thread to be processed can be moved along its own length along the path while being treated by the processing elements. The processing elements can comprise twisting, heating, cooling and forwarding (transport) elements - the forwarding elements can be mutually arranged so as to generate a drawing effect.
The texturing position 10 shown in Fig. 1 comprises

a support 11, for example in the form of a framework with a foot part 12, which stands on the floor (not shown) of a workroom;
a thread path 13 indicated by dotted lines;
a plurality of heating units HU (three in the example shown here);
a thread forwarding unit FU;
a twisting unit TU;
a winding unit WU, comprising an infeed (triangle) guide 14 and a winder with a cradle 15 to receive a bobbin tube 16. The cradle is pivotally mounted for rotation about an axis 17, which is fixed relative to the support 11;
utilities such as a motor/compressor set 18 (on the foot portion 12) and a man-machine interface, for example in the form of a keyboard 19 and a GUI (graphical user interface, or display) 20 supported in this example on a side-arm 21 pivotably mounted (not shown) on the support frame 11.

The winding unit WU also comprises certain standard elements which cannot be seen in Fig. 1 but which are well-known to the man skilled in this art, for example a friction drive roller (or "bowl") which drives the bobbin tube into rotation by frictional contact with the tube or a thread package (not shown) building thereon, and a traverse device (not shown) for traversing the thread back and forth along the length of the bobbin tube to give the required package build.
The starting point of the thread path 13 is not specifically indicated on Fig. 1 but the direction of movement of a thread along the path is indicated by the arrows beginning with the arrow "In". From its non-illustrated starting point the thread moves vertically downwards to the first heating unit HU1, thence laterally (on a short horizontal stretch of the thread path) to the second heater unit HU2, from there vertically to the twister TU, from the twister vertically to the third heater unit HU3 and from the third heater laterally to the forwarding unit FU. From there, the thread travels vertically downwardly into the winding unit WU where it first contacts the triangle guide 14 before passing onwards to be wound on the bobbin tube 16. A spin finish applicator (not shown) can be provided between the forwarding unit FU and the triangle guide 14. The traverse stroke, defined by the previously mentioned traverse device, is indicated at S in Fig. 1 and it forms the base of a triangle, the apex of which is defined by the guide 14 and the sides (dotted lines) correspond to the limits of the sweep of the thread in its traverse movement. The height of the traverse triangle is indicated at H.
It will be noted from Fig. 1 that the thread path 13 is arranged in a substantially rectangular configuration with the winder 15,17 at one lower corner, the corresponding vertical side of the rectangular configuration being occupied, for the greater part, by the traversing triangle. Location of the winder at a lower corner enables exploitation of the elongated framework to leave space for a traverse triangle of unusual height H, this height being desirable for high speed operation, i.e. operation with a linear thread speed along the thread path in the region above 1500 m/min. and preferably in the range 2000 to 2500, or even 3000 m/min. The height H may be selected in the range 1 to 2 metres.
The (vertical) side of the rectangular configuration opposite the traversing triangle is formed by a straight path section on which the actual texturing operation takes place as the thread approaches the twister TU from below. A thread moving along this path section is drawn past a cooler C which preferably exerts the required cooling effect without contacting the thread. The present invention can employ any appropriate cooling system, but preferably one employing so-called active cooling. Cooling principles suitable for use in this invention have been disclosed in both US 6609277 and WO 01/38620 and those principles can be adapted without difficulty to the present embodiments; there is therefore no need to repeat the relevant disclosure here. The infeed section of the thread path is disposed in the available space between the previously mentioned side sections and is preferably arranged parallel to both of them.
The "total operating height" (not indicated) of the texturing position 10 is important for the ergonomics of the design. This height may be considered as the height above the floor (not indicated) of the highest point of the texturing position 10 which must be reached by a person performing normal operating or attendance (not maintenance) functions. The total operating height is preferably so selected that an adult attendant standing on the floor in front of the texturing position can reach all points within that position (possibly with the aid of a manipulating device such as a suction pistol) to enable threading of a thread to be processed into the processing units disposed on the thread path as described. A total operating height of about 2 metres is suitable. In the illustrated example, the total operating height will be determined by the height at which the units HU3 and FU are mounted on support 11. The height of the unit FU determines the space available for the traverse triangle.
The winder 15,17 represents the end of the thread path in this texturing position 10. The other three corners of the rectangular path are occupied by the units HU2, HU3 and FU. Heater Unit HU1 is provided at the location at which the thread passes from the infeed thread path section to the main processing path. These units each perform an active processing function, as will be described further below, but they also serve to divert the thread from the immediately preceding (upstream) section to the immediately succeeding (downstream) section of the thead path. This diverting or guiding function will also be further described below. In this example, the angle of diversion at each corner of the thread path is substantially 90°, but the selection of this angle is not an essential feature of the invention. In general, the illustrated arrangement enables achievement of very low dynamic friction between the thread and surfaces contacted by the thread while travelling along the thread path. In particular, the devices serving as diverting guides at those points on the path where a significant diversion angle is unavoidable are adapted to generate substantially only static friction by contact with the thread. This will become apparent from the subsequent more detailed disclosure of such devices and their components.
The forwarding unit FU is designed to isolate the region of relatively high thread tension around the winding unit WU from the region of relatively low thread tension immediately upstream from the forwarding unit. This measure enables insertion of an interlacing jet (not shown in Fig. 1) in the short stretch of the thread path between heating unit HU3 and forwarding unit FU. For the purpose of separating thread path regions of different thread tension, unit FU can comprise a godet (or galette). The forwarding unit can be constructed in essentially the same way as the heating units HU, but without the means for supplying heat to the unit. The heating units HU will be described subsequently with respect to Fig. 3 and 4, and a possible embodiment of the forwarding unit FU will be described with reference to Figure 4.
Figure 2 shows further detail of an embodiment based on the principles already described with reference to Fig. 1. The same reference symbols are used as far as possible. The threadline has not been indicated in Fig. 2 apart from the indication (in dotted lines) of the traverse triangle, but it follows the path previously described. As can be seen in the perspective view in Fig. 2, the framework 11 supports upper and lower panel members 22, 23 respectively. These panels act as bearers for an upper group of processing modules, comprising twist unit TU, heater unit HU3 and forwarding unit FU and a lower group of processing modules, comprising heater units HU1 and HU2 together with cooler C. The face of each panel supporting processing elements is referred to here as the "front face" (or simply the "front") of the panel.
The reverse face (or "back") of the upper panel 22 can carry a creel (not seen in Fig. 2) which in use carries feed packages (cross-wound spools or "cheeses") from which thread is unwound for processing in the processing elements of the texturing position. A part of one such package is seen at 24 in Fig. 2 and it can be assumed that this package is mounted on a mandrel (not seen) supported on the back of panel 22. Another mandrel, with a similar package, is located below the package 24 - while thread is being unwound from one package of the creel pair, the other forms a reserve enabling continuous operation of the texturing position provided an exhausted feed package is replaced in good time before the current feed package becomes exhausted. The principle of continuous feeding of a texturing position using a sequence of thread packages is very well known and will not be described here. It is not an essential feature of the invention. An alternative arrangement, involving online texturing, is shown in US 5724802, mentioned in the introduction, and equally applicable for use in combination with the present invention.
In the case of on-line texturing, the thread to be processed would enter the texturing position from above. The arrangement is not shown in the Figures, but is clearly possible for a configuration as shown in Fig. 1. In the case of a creel, as indicated in Fig. 2, the thread to be processed has to be passed from the back to the front of the panel 22. This is enabled by providing the panel with a hole forming a thread passage (not seen) aligned with a thread guide 25 supported on the panel so as to project forwardly therefrom. An auxiliary device (not shown) may be provided to assist in passing the thread through the hole in the panel, for example, a suction device could be provided on the front and/or a pressure jet on the back of the panel 22 to cause an airstream to flow though the hole.
At the free end of guide 25 the thread is deflected from the horizontal path through the passage into the vertical "In" section of the thread path 13 already described with reference to Fig. 1. The free end of guide 25 preferably lies in a "processing zone", which can be considered as an imaginary parallelepiped containing the remainder of the thread path 13. The spacing of the major faces of the processing zone, as viewed for example from the side of the texturing position 10, is adequate to accommodate departures of the thread path from a simple plane, for example due to wrapping around godets as described later in the text and/or a slight forward inclination of the traverse triangle. However, this spacing can be kept small and the processing zone as a whole can be kept within narrow bounds parallel to the support structure. A thread cutter 26 is mounted on panel 22 just below guide 25. This can be operated by the control system, described below, so as to cut the thread if suitable sensors (not shown but known to persons skilled in the art) indicate unfavourable thread processing conditions. The operating portion of the cutter is located in processing zone.
As seen in Fig. 2, twisting unit TU comprises a U-shaped yoke 27, the base of the "U" being fixed to the upper support panel 22 so that the arms project forwardly horizontally to provide upper and lower spindle support members 28, 29. The preferred arrangement will be described subsequently with reference to Figure 6. The yoke provides a mounting for a friction disc stack 30, the preferred example of which will be described in greater detail below. In general, the twist unit can comprise a three-spindle stack of the kind shown generally in Scragg DE-A-2444530. Support members 28, 29 therefore each have a cut-out 31 which permits passage of thread though the middle of the stack, and also permits threading-up by inserting the thread into the stack from the front of the texturing position 10. The invention is not, however, limited to this particular form of disc stack. An alternative, using only a single spindle shaft, is shown for example in US 3998041, and it would also be possible to use more than three spindles.
Winding unit WU shown in Fig. 2 comprises a casing 32 carried on the foot portion 12 of the framework 11. This casing houses drive and control systems (not shown) for the friction roll partly visible at 33 and for the traverse mechanism partly visible at 34.
Each unit HU1, HU2, HU3 and FU comprises a respective mounting plate 35 which is fixed to the respective support panel 22 or 23. Each mounting plate 35 forms a base on which the respective unit can be built.
The basic structure of the heater units HU (HU1, HU2 or HU3) is shown in Fig. 3 and specific elements are shown in greater detail in Fig. 4. Each unit HU comprises a pair of godet modules 36, 37 respectively within a rectangular enclosure made up of

long side walls 38, 39;
short side walls 40, 41;
a floor 42, and
a cover 43 (Fig. 2).

wall

similar aperture

aperture

respective mounting plate

respective bearer panel

floor

plate

As best seen in Figure 4, each godet module 36, 37 comprises a flange 46 carrying a motor support pedestal in the form of a tube 47. Each tube 47 provides support surfaces (not shown) for a godet drive motor 80 having an output shaft 81. A hollow cylindrical godet element 48 is fixed to the end of the shaft by a suitable connection indicated diagrammatically at 49. The arrangement has the advantage that the motor bearings (not shown) also serve as rotary bearings for the godet element 48 and these bearings are located within the working region where the module is subjected to loading by wraps of a thread being processed on the cylindrical outer surface of the godet element. The arrangement ensures that this loading is taken up as far as possible without creating bending moments. The dimensions of the godet elements 48 can be small relative to those of conventional godets. The diameter of the envelope surface that carries thread wrappings in use can be of the order of 60 mm, say 45 or 50 mm. up to about 75 mm. The length of the envelope surface (parallel to the axis of the godet) can be of the order of 55 mm, say 40 mm. up to about 70 mm.
The godets 48 are not directly heated. Instead, heat is supplied to the interior of the enclosure by means of four electrically heated rods 50 (Fig. 3). Any suitable number of rods could be used, the group of four being selected simply for optimal space utilisation in the illustrated embodiment without placing the whole heating load on a single rod. Heat transfer to the thread is effected by convection and radiation as well as by conduction in the region of contact with the cylindrical godet surfaces. The rods 50 are grouped and located between the godet modules 36, 37 as viewed in Fig. 3 so that there is no direct contact between the thread and any one of the hot rods. This will be clear from a more detailed consideration of the thread path through the enclosure.
In the case of the heating unit HU1 (Fig. 2) the thread enters the unit by way of the aperture 45 in the short wall 40 (Fig. 3). Within unit HU1, the thread is wrapped several times around the godet pair 36, 37 - first contacting godet element 48 of module 37 and then godet element 48 of module 36. Finally, the thread leaves the heating unit via the aperture 44, the final point of contact within the unit being on the cylindrical surface of godet element 48 in module 36. Unit HU1 is so arranged relative to the thread path 13 (Fig. 1) that the thread enters the unit along a line extending tangentially to the outer surface of godet element 48 of module 37, and it leaves the unit along a line extending tangentially to the surface of godet element 36. Each aperture 44, 45 is so dimensioned, and the heating unit itself is so disposed relative to the thread path 13, that the thread enters and leaves the unit without contacting the sides of the apertures 44 and 45, but the previously mentioned thread guides may be required to ensure the correct approach to and/or departure from the godets 48. The number of wraps of the thread on the godet elements is chosen to give a selected (predetermined) dwell time for the thread within the heating unit. The detailed construction of each heating unit (especially the disposition of the apertures) must be adapted to its specific position in the line, but the principles involved are the same in all cases.
When the heating unit is ready for use, the internal surfaces of the enclosure are faced with a material having good heat insulating properties. However, this layer of insulating material has been omitted from Figure 3 to show the structure beneath it, especially the floor 42. The floor has two openings 83 through which respective tubes 47 project into the enclosure and four openings 84 through which respective heater rods 50 project into the enclosure. In use, these openings are covered by the insulating material. Each godet module 36, 37 is secured on the associated plate 35 by means of a tensioning element diagrammatically indicated at 86, this element being secured at one end to the flange 46 and at the other end to the plate 35.
In the illustrated embodiment, the godet mountings are also adjustable so that the rotational axes (not indicated) of the godets can be arranged skew (or canted) relative to each other. This adjustability can be dispensed with after optimum settings have been established - the godets can then be mounted with their axes disposed at predetermined angles relative to the mounting plate 35. In the illustrated arrangement, the adjusting mechanism comprises in each case the previously mentioned tensioning element 86 together with a set of three rods 51 supported in mounting plate 35 (Fig. 4) and each individually movable along its own length as indicated by the arrows (the moving means is not shown in the schematic illustration). Each rod 51 engages a respective abutment 52 fixed to the associated flange 46. The tensioning element 84 can be tightened to draw the flange against the ends of the rods 51, the final disposition of the godet relative to the plate 35 being dependent on the positions of the ends of the three rods associated with that godet. A single rod 50 is also indicated in Figure 4. In practice, the heater rods 50 can be secured to the floor 42 so that they can project through their respective openings 84 into the enclosure. Suitable electrical leads (not shown) are provided behind the mounting plate to supply electrical energy to the rods 50.
It will be apparent from Figure 4 that the motors 80 could be subjected to considerable heat stress due to the fact that they are located at least partially within the heated enclosure. So far as the motors are designed to withstand such stress, there will be no need to take any special precautions although it will clearly be desirable to provide a layer of insulation (not shown in Fig. 4) between the motor body and the surrounding tube 47 which provides some protection from the unfavourable environment in the heated enclosure. If this proves insufficient, a stream of cooling air can be supplied to the interior of the tube 47.This can be arranged by providing a tubular partition (not shown) within the tube 47 to divide the space between the motor body and the tube wall into an inner region adjoining the motor body and an outer region adjoining the tube wall, these two regions being in direct communication with each other at the free end of the tube 47 within the enclosure. Cooling air can then be supplied by suitable leads (not shown) from behind the mounting plate 35 into the inner region adjoining the motor body, and this air can flow from the inner region to the outer region adjacent the tube wall from which it can be withdrawn via further leads (not shown). If this also proves inadequate protection fro the motors 80, then the overall arrangement can be modified to shift the motors outside the heated space, i.e. the motor and godet element of a given module 36, 37 can be mounted "in line" instead of "enwrapped" as illustrated. Further detail of suitable motor types will be given in the subsequent description of the drive motors for the twist unit TU.
The use of positively driven godets is not an essential element of this (thread heating) aspect of the invention. The enclosure could be fitted with passive roller guides, which simply rotate due to contact with the thread. However, two features of the positively driven embodiment are advantageous:

firstly, the use of two skewed and positively driven godet rolls assists in creation of a threadline which generates minimum dynamic friction on the processed thread - substitution of one driven roll by a canted passive roll (a possible arrangement well known in the art) would lead to an increase in dynamic friction;
secondly, the godet units can be employed to draw the processed thread between successive heating units, e.g. between HU1 and HU2. This can be achieved, for example, by driving the motors of unit HU1 in a braking mode and the motors of unit HU2 in a positive drive mode. It follows, that each motor 80 is preferably designed for so-called four-quadrant operation.

Each heating unit HU is preferably provided with a so-called "smoke extractor" (not shown here). This is basically a suction system extracting air along with fumes and vapours from the interior of the enclosure. Means may be provided to re-circulate the warm air after treatment to remove noxious material. A hot air circulation system of this kind could provide an alternative means of supplying some or all of the required heat to the interior of the enclosure.
As previously indicated, the forwarding unit FU can be constructed in essentially the same way as the heating units HU since each of these units is designed to exert a transporting (or braking) effect on the thread. The unit FU can therefore be considered to comprise a pair of godet modules similar to the modules 36, 37 shown in Fig. 3. However, because the forwarding unit FU does not have to fulfil a heating function, the heated rods 50 shown in Fig. 3 and 4 can be omitted from the forwarding unit FU (or simply not energised in that unit). Furthermore, the enclosure is also unnecessary if there is no possibility that the unit FU may have to be modified under some operating circumstances to act as an additional heater. The modules 36 and 37 can then be simply mounted on the plate 35, as actually shown in Figure 4, without any surrounding housing (and without any associated rods 50).
A preferred embodiment of the twisting unit TU will now be described with reference to Fig. 5, which again shows the upper and lower arms 28, 29 of the yoke previously described with reference to Fig. 2. As seen in Fig. 5, however, the yoke carries two side walls 53, 54 each designed to fulfil a safety function as further described below. The left hand side wall 53 (as viewed from the front) also serves as a support for a hinge 55 by means of which a front wall 56 is pivotally mounted on the yoke. In this preferred embodiment, the front wall is transparent and therefore does not appear as such in the schematic illustration in Fig. 5 - in that figure, the front wall is shown in its operative position in which it closes the front face of an enclosing casing 57 formed by the yoke, the side walls and the transparent cover or door.
The primary function of the casing 57 lies in safety for parts and persons in the neighbourhood of the disc stack, bearing in mind the fact that the discs are designed to rotate at very high RPM but may be subject to breakage at those speeds. The walls of the casing, including the front wall or door 56 are therefore designed to absorb the impact of flying disc parts. In a desirable further development, the door may be lockable in its closed position, although the locking means has not been shown in Figure 5. The lock may be electrically interlinked with the drive control for the disc stack so that the door is locked automatically when the RPM of the stack rises above a predetermined level and cannot be re-opened until the disc stack has slowed below a predetermined revolution rate.
In order to assist in threading the twisting unit, the door 56 is fitted with a threading unit comprising a bar 58 with a handle 59 and a pair of legs 60 extending through openings (not apparent in Figure 5) in the transparent cover. These openings are aligned with the cut-outs 31 described with reference to Fig. 2. At its inner end (within the casing) each leg 60 has a thread receiving slot (not seen in Fig. 5). The threading unit is normally held in an inoperative condition by spiral compression springs 61 encircling each leg between the transparent door 56 and the bar 58. The threading unit operates as follows:

after opening of the door 56, the thread to be processed is engaged with the slots in the legs 60 of the threading unit;
the door is then closed;
bar 61 is then pushed inwards towards the interior of the casing 57 against the effect of the springs 61;
the extent of movement permitted by the length of each leg 60 and the degree of compression of the spring 61 is sufficient to move the thread along each cut-out 31 into the middle of the disc stack 30 (Fig. 2).

In a further desirable development, not shown, the legs 60 are fixed to the door 56 and simply act as guide rods for sliding movement of the bar 58 between its stand-by position (illustrated) and its operative position closer to the door 56. Bar (slider) 58 has openings to receive the guide legs 60 and is also fitted with additional arms (not shown) extending from the bar into the casing 57 through appropriate openings in door 56. These latter arms are then provided with thread guides on their free ends within the casing. A thread guide (not shown) may be provided at the thread entrance to and/or exit from the casing 57 to ensure that the thread travels through the twist unit TU along a straight path. The threading device is adapted to push the thread into the guides which retain it in a substantially predetermined disposition relative to the disc stack. This aspect of the invention is not limited to the particular embodiment of threading device shown simply by way of example - it will be clear, for example, that the threading device could be mounted on a side wall rather than on the door 56. Further, since the door 56 has to be opened anyway to insert the thread, the threading device could be provided next to the twist unit TU and could include at least one pivotable arm arranged to swing into the casing 57 to insert the thread into the stack.
As previously indicated, the stack itself comprises three spindle shafts 62, each carrying a plurality of discs 63, the discs overlapping, as is well-known in the art, to define a central passage in which twist is imparted to the thread by frictional contact with edges of the discs. Only two such shafts 62 are visible in Fig. 5 although the discs of the third shaft can also be seen at the back of the box 57. Each shaft 62 is mounted by suitable bearings, preferred embodiments of which are further described below, at its lower end in arm 29 and at its upper end in arm 28, i.e. each shaft is supported by top and bottom bearings. This is not new in itself - however, the illustrated arrangement differs significantly from the prior art in that each shaft is directly coupled to respective individual drive motor 64 outside the box. The texturing position 10 includes a suitable motor control system by means of which the rate of revolutions of the three drive motors can be coordinated, the motors preferably being synchronised. This system could, for example, comprise a device (not shown in Fig. 5) designed to generate an analog control signal that can be provided to individual motor controllers provided for the three drive motors, each controller being arranged to provide the required energising current to its respective motor. Alternative control systems will be referred to below.
In the illustrated embodiment, the spindle shafts are arranged parallel; it would, however, be possible to incline the axes of the spindle shafts so that the disc stack exerts a forwarding effect on the thread. The twist unit TU may also be provided with spindle braking means (not shown). These could be operated automatically, for example, if the safety casing is opened while the disc stack is rotating. Further, a sensor could be provided to detect thread break and to initiate one or more consequential actions such as braking of the disc stack, opening of the door, energising an alarm, causing display of an appropriate indication on the display etc. The twist unit shown the illustrated embodiments has a one-piece support yoke in which the shafts are mounted. However, it may be desirable to provide for "opening" of the disc stack, for example to facilitate threading up. Support structures enabling this function are known in the prior art, e.g. in Temco US 5414989, and they can be adapted for use in combination with the present invention also.
Preferably, means (not shown) is provided to condition the interior of the casing 57 and/or to extract waste material such as dust, particles and vapour generated during processing. These means may include an air infeed and/or a suction extractor.
Figure 6 shows an individual spindle module 90 in more detail especially as regards the coupling of the spindle shaft 62 with the respective drive motor 64, and the bearing structure by means of which the shaft is mounted at or near both ends in the support yoke. Only one such module has to be described because the others can be designed in the same way subject to well-known modifications, for example relating to the number of discs provided on each individual shaft 62 in the stack. As shown in Fig. 6, spindle shaft 62 has a flange 91 at one end and an axially projecting stub 92 at the other. Stub 92 has an external screw thread 93 between its ends and an internally tapped blind bore 94 in its free end portion. In use, a first spacer ring 95 engages flange 91 and this ring 95 is engaged by a disc 63. The arrangement then depends on the number of discs 63 to be mounted on the shaft; in the illustrated example, two discs 63 are provided with an axial separation determined by the intervening spacer ring 96, but this can be selected as required by the stack design. In any event, a further spacer ring 97 is provided between the disc 63 furthest from the flange 91 and the adjacent end of the shaft 62.The spacer rings and discs are then clamped together and against the flange 91 by a nut 98 which engages with the screw threads 93 on stub 92. The nut 98 provides an abutment surface 99 for a rotary bearing 100, for example a ball or roller bearing having an outer casing 101 with a cylindrical outer surface provided with an annular groove 102. In use, this groove receives an O-ring of rubber or suitable elastomer for a purpose described below. The bearing casing is held in engagement with the abutment surface 99 by means of a retaining screw 104 cooperating with the tapped bore 94.
At the other end of the spindle shaft 62, one axial face of the outer casing 105 of motor 64 sits against the flange 91 and is retained thereon by suitable means which have not been shown in this drawing. The outer casing carries the motor stator windings (not shown) which can be energised by way of suitable electrical leads 106. The rotor is indicated schematically at 107 and it is of course mounted by way of suitable bearings (not shown) for rotation about its own axis within the casing 105. Rotor 107 is fitted with an output shaft 108 which projects into a suitable bore (not specially designated) in the adjacent end face of spindle shaft 62. The motor shaft 108 and the receiving bore in the spindle shaft 62 are formed to interengage (form-fit) in such a way that the spindle shaft must rotate with (or brake rotation of) the motor shaft 108. As shown, each motor 64 sits on the uppermost end of its respective spindle shaft 62; this is not essential - the motor could be secured to the lower end of the spindle shaft.
Motor 64 may be of the so-called brushless type having a rotor 107 made up by permanent magnets (not specifically indicated in Fig. 6). This kind of motor, which is now well known in the textile machinery field, can be fitted with a sensor (diagrammatically indicated at 109) providing an incremental output.signal that can be evaluated to indicate the angular position of rotor 107 within casing 105. This signal can be used for motor control as briefly described (in outline) hereinafter. The previously mentioned motors 80 in godet modules 36, 37 (Fig. 4) can be of the same general type. The invention is not, however, limited to this kind of motor. Another motor type that could be used with advantage in this context is the so-called variable reluctance motor having a magnetic circuit made up of a stack of metal sheets, i.e. without the permanent magnets of the brushless dc motor.
Motor casing 105 is fitted with an external O-Ring 110 similar to, but of larger diameter than, the O-Ring 103. Motor 64 has to cooperate with arm 28 (Fig. 2 and Fig. 5) of the support yoke, and the end of spindle shaft 62 remote from the motor has to cooperate with arm 29 of the same yoke. The preferred form of cooperation is illustrated and will be described for the combination motor 64 - support arm 28. The same form of cooperation is preferred for the combination spindle shaft 62 - arm 29, as will be apparent from the following description although the second combination is not specifically illustrated.
As shown in Fig. 6, arm 28 is actually made up of two plates 111, 112 abutting face-to-face and held together in this configuration by any suitable means (not shown). Each plate has an opening 113 to receive the motor casing 107, the internal diameter of the openings 13 being larger than the external diameter of the casing 105. The edges of these openings at the adjoining faces of the plates are chamfered to provide a groove 114 which opens towards the casing 107. This groove receives the O-Ring 110 which is slightly over-dimensioned for the groove so that it is compressed therein and grips the motor casing 107 tightly. The O-Ring holds casing 107 firmly in the opening 113 without contact between casing 107 and plates 111, 112; however, the O-Ring itself is free to distort within the remaining gap between the plates and the motor casing and the elastomeric ring therefore serves as a vibration damper for the motor, dissipating vibration energy in its own elastic deformations.
Arm 29 (not shown in Fig. 6, see Fig. 2 and Fig. 5) is constructed out of two clamping plates in the same way as arm 28, and these plates have openings, similar to the openings 113, to receive the portion of spindle shaft 62 carrying bearing casing 103. Further, the openings in the clamping plates of arm 29 are also formed with chamfers to form a groove which receives the O-Ring 103. As in the case of the O-Ring 110, the O-Ring 103 is slightly over-dimensioned for its receiving groove, and the openings in arm 29 are of larger diameter than the part of the spindle shaft they receive.
Accordingly, the spindle shaft module 90 is mounted top and bottom by means of elastically deformable mountings which can absorb energy when they are subjected to vibrations and which hold the module 90 firmly in place without any direct contact between relatively rigid components - a "fully-floating" mounting structure
Fig. 6A illustrates diagrammatically a possible modification of the arrangement shown in Fig. 6. According to this modification, the rotor is built up directly on the spindle shaft and the stator windings are placed around this rotor. Accordingly, instead of coupling a motor shaft to a separate spindle shaft, a single shaft is used for the spindle and for the motor (fully integrated design). In Fig. 6A the portion of the spindle shaft used to carry the discs (not shown) is indicated at 115. This largely- conventional portion now has an extension 116 which is formed with a plurality of grooves 117 - the illustrated embodiment has four such grooves, only three being visible in Fig. 6A. Each groove 117 receives a respective permanent magnet 118, two such magnets being indicated in Fig. 6A. The shaft portion 116 therefore now constitutes the motor rotor and is surrounded in use by the stator windings indicated schematically at 119 to form an electric motor integrated with the spindle shaft. As before, a sensor (not shown) can be provided to detect the angular disposition of the shaft around the longitudinal shaft axis and this sensor can be integrated into a suitable control system.
A bearing for this integrated assembly can now be provided directly on the shaft, for example as indicated at 120 and the assembly can be provided with an elastic, vibration damping mounting as indicated by the O-Ring 121 in Fig. 6A. The vibration damping feature is not, of course, limited to the use of O-Rings as shown here simply by way of example - alternative damping systems are known and can be used for the spindle module of this invention. It will also be appreciated that the spindle shaft now effectively "passes through" the motor and can be extended further beyond the windings 119 - for example to receive another bearing unit (not shown).
It is especially worthy of note that the external diameter of the motor casing 105 is smaller, in the illustrated example significantly smaller, than the centre-to-centre spacing of the spindle shafts. This enables the motors to sit "next to each other" without mutual interference in the twist unit although the discs are overlapped as shown in Figs 2 and 5. In fact, the external diameter of the motor can be, and preferably is, selected to be approximately equal to the external diameter of the spindle shaft.
A control system for a texturing position 10 provided with these various modules is indicated in outline in Fig. 7. The system comprises a central programmable controller such as the PC shown at 130. The PC is programmed to provide digital output signals representing set values for various processing parameters of the texturing position, e.g. spindle speed (RPM), heater temperature, draw ratios as represented by motor revolutions of the various forwarding drives including that of the forwarding unit FU, take-up speed at the winder, traverse rate etc. In order to simplify the illustration and to avoid superfluous detail, only one control link of each type is specifically shown in Fig. 7, but it will be clear that the illustrated links can be replicated to control other elements. The diagram therefore shows only one spindle motor 64, one godet motor 80, one heater rod 50 and one drive element D (for example, the drive for the friction roll 33, Fig. 2) of the winder unit WU. The programmed set point signals for the spindle motors 64 are sent to respective motor controller units 131 (only one shown in Fig. 7). Each controller 131 controls the supply of electrical energy from a suitable dc source DC to the associated motor 64.
As indicated at 132, and in accordance with the preferred arrangement, each motor 64 is controlled by reference to feedback signals supplied, for example, from the previously mentioned sensor 109 (Fig. 6) to its respective controller 131. The arrangement for controlling the godet motors 80 is essentially the same, one godet motor controller 133 being shown in Fig. 7 and being linked by a feedback link 134 to a sensor (not shown) in its associated motor 80. It will be clear to a person skilled in the art that this control system permits very flexible setting of operating parameters. Thus, the motors 64 of the spindle can be operated at the same set rate of revolutions, or at individually programmed rates of revolution. The expression "synchronised" is to be understood in a correspondingly broad sense, indicating simply coordinated control of the motor revolutions. The same applies of course to the godet motors, where differing rates of revolution will be required to generate predetermined draw ratios.
In Fig. 7 it has been assumed that the winding unit and each heater draws energy from a common mains source 135. A controllable heat generator 136 converts this electrical energy into heat which is supplied to one (or possibly more than one) of the rods 50 (Fig. 3). In this case, the feedback link is less direct - the controller responds to a signal from a temperature sensor TS to control supply of heat to the rod(s) 50 in dependence upon a set temperature determined by the programming of PC 130. The arrangement could be such, for example, that a single controller 136 is associated with all four rods 50 of a given heating unit HU and energises, or de-energises, the heat supply to those rods in dependence upon temperature sensed by sensor TS within the associated enclosure described with reference to Fig. 3. The drive motor D illustrated within the winding unit WU is driven by an inverter Inv also in dependence upon a set point signal from PC 130. The drive/control arrangement of the winder is conventional and well-known and will not therefore be described here. The overall control principle will however be clear from the previous description - the programmable controller serves as a coordinating unit for the complete texturing position.
It is worth mentioning at this point that the invention is not limited to a single processing position - multiple positions can be provided and each can comprise components and/or assemblies and/or layout configurations according to one or more aspects of the present invention. The multiple positions can be controlled and operated individually (independently) or they can be controlled in unison by a single coordinating control device, preferably a programmable controller, or a combination of control techniques can be adopted.
The set points generated by the PC can be programmed to vary over time. As an example of this feature, a start/stop procedure suitable for a high speed machine will now be described briefly with reference to the time/speed diagram shown in Fig.8, with time represented on the horizontal axis. Only the principle of the procedure is to be explained by reference to this diagram which can be taken as representing varaiation in the speed of any arbitrarily selected motor in the threadline. Thus the motor is assumed to be run up from standstill to a predetermined threading speed V1, corresponding to a given linear thread speed, for example 500 m/min, at which the operator can thread the position without undue difficulty or safety precautions. During threading, the thread is taken up by a suction pistol - this is a well-known operation and will not be described in detail. When the machine has been threaded and is running stably, the acceleration procedure is re-started so that the drives run up to full set operating speed indicated in Fig. 8 at V2.
During run up to operating speed, the thread is still taken up to waste by a suction device which can be located close to the winder as indicated diagrammatically at 140 in Fig. 2. This is preferably the suction pistol previously used for manual threading, although transfer to an automatically operating device (manipulator or robot) is also possible. When the machine has reached operating speed, a signal is sent to the central, coordinating, controller, in Fig. 7 PC 130, following which the following sequence of steps is carried out either manually or under automatic control:

the suction take-up is manipulated to bring the thread into engagement with the surface of bobbin tube 16 (Fig. 2), which is rotating at take-up RPMs;
the thread is thereby "wiped" across a catching slot 141 formed in the bobbin tube (this kind of slot is well-known and will not be described);
the thread downstream of the catching slot is brought into engagement with a cutter or is cut, for example, by a cutter in the manipulator, so that the thread is now connected with the bobbin tube and released by the suction take-up.

The man skilled in the art will recognise that the various aspects of the invention are not limited to use in false twist texturing machines. The following possibilities for alternative uses are given by way of example only:

thread heating units, such as units HU, could be used for setting plied yarns after doubling (twisting), for example in production of carpet yarn by doubling;
the heating units could also be used in air jet texturing machines, for example of the kind shown in EP 373519
the yarn path configurations described here could also be used in other machine types, for example air jet texturing machines.;.

Furthermore, even within the field of false twist texturing, the various aspects of the invention are not limited to use in combination. The twisting unit TU could be used with advantage in an otherwise conventional machine design and configuration. The yarn path configurations could be used with conventional processing elements. The texturing position illustrated in Figs. 1 and 2 comprises a setting heater HU3 - this is not always required and can of course be eliminated for certain processes (polymer types and yarn characteristics). Equally, the position can be modified by adding elements conventional auxiliary elements such as detorque jets, etc. The twist unit TU explained here is not designed for any specific maximum rate of revolutions. Today, the available spindles work in the range 15,000 to 20,000 RPM. The concepts put forward in this invention certainly enable rates of revolution above 20,000 RPM and it is anticipated that these concepts are suitable for rates of revolution at least as high as 35,000 to 40,000 RPM. On the other hand, the twist units explained here can be sued with advantage at conventional speeds, i.e. there is no "obligation" to exploit the full capabilities of the system in any given case.

Claims

A thread heating device for use in a thread processing machine, for example a false twist texturing machine, comprising a heat insulating enclosure and heating means for supplying heat to the space within the enclosure
characterised by
at least one rotary thread guiding means disposed within the enclosure.
A device as claimed in claim 1 characterised by at least one rotary thread forwarding means.
A device as claimed in claim 1 or claim 2 characterised by at least one heating element separate from the guiding means.
A device as claimed in claim 3 characterised in that the arrangement is such that heat transfer to thread takes place without contact with the thread.
A device as claimed in any preceding claim characterised in that the enclosure comprises a door and the guiding means comprises elements mounted cantilever-fashion opposite the door.
A device as claimed in any preceding claim characterised in that the guiding means is positively driven.
A device as claimed in claim 6 characterised in that a drive motor for the guiding means is provided inside the enclosure, preferably inside the guiding means.
A device as claimed in claim 7 characterised in that means is provided to supply a stream of cooling air to the motor.
A device as claimed in claim 6 or claim 7 characterised in that the motor is supported by vibration damping means.
A galette or godet unit especially for use in a device as claimed in any preceding claim, the unit comprising a hollow body having a cylindrical surface to receive at least one thread wrap, and a drive motor adapted to rotate the body about the axis of the motor output shaft
characterised in that
the cylindrical surface has a diameter not greater than 80 mm. and the drive motor is disposed within the hollow body.
A twisting device for use in a process employing false twist, for example false twist texturing, comprising a support means and a plurality of spindle shafts each mounted on the support means for rotation about the longitudinal axis of the shaft and each adapted to carry a respective plurality of discs,
characterised by
a plurality of electric drive motors associated individually with respective spindle shafts so that each drive motor can cause rotation of its respective associated shaft about the longitudinal axis of that shaft.
A device as claimed in claim 11 characterised by an electronic control to synchronise the motors.
A device as claimed in claim 12 characterised in that the control comprises a programmable controller.
A spindle module for use in a twisting device comprising a disc support shaft and an electric drive motor directly coupled to or built on the shaft characterised in that the outer diameter of the drive motor is less than the centre-to-centre spacing of the spindle shafts.
A spindle module for use in a twisting device comprising a disc support shaft, a motor connected to the shaft and a bearing for mounting the shaft and/or the motor in a support
characterised in that
the bearing is adapted to be connected to the support by elastically deformable mounting means.
A spindle module as claimed in claim 15 characterised in that two bearings are provided at respective locations mutually spaced along the longitudinal axis of the module and each bearing is a adapted to be connected to the or a support by elastically deformable mounting means.
A high speed twisting device for use in a process employing false twist, for example false twist texturing, comprising a support means, at least one spindle mounted on the support means for rotation about the longitudinal spindle axis and adapted to carry a plurality of discs and drive means adapted to rotate the spindle with the discs at high speed, for example above 20,000 RPM (???),
characterised by
at least one protective wall fixed to the support means to absorb impact energy in the event of a failure of a rotating part in use.
A device as claimed in claim 17 characterised in that the wall is transparent.
A device as claimed in claim 17 or 18 characterised in that the wall is part of a casing, all of the walls being designed to absorb impact energy.
A device as claimed in claim 19 characterised in that suction means is provided to extract waste material such as dust, particles and vapour from the casing.
A device as claimed in claim 19 or 20 characterised in that means is provided to pass a stream of cooling air through the casing.
A device as claimed in any of claims 19 to 21 characterised in that means is provided to sense the temperature at a predetermined location within the casing.
A device as claimed in any of claims 17 to 22 characterised in that the casing has apertures to permit thread passage.
A device as claimed in claim any of claims 17 to 23 characterised in that the casing has means to assist threading up.
A device as claimed in claim any of claims 17 to 24 characterised by three spindles.
A thread processing machine, for example a false twist texturing machine, comprising a support structure, a creel and thread processing elements
characterised in that
the support structure is arranged to provide a front face and a reverse face;
the thread processing elements are supported on the front face;
the creel is supported on the reverse face, and
thread guide means is provided to guide a thread from the creel to an infeed point of a yarn path which leads successively to each of the thread processing elements on the front face.
A false twist texturing machine comprising a support structure, a winding means with an infeed guide and a winding unit, and a straight section of a texturing path with a twist unit, a cooler and a heater
characterised in that
the texturing path is disposed substantially parallel to the path of the thread from the infeed guide to the winding unit.
A machine as claimed in claim 27 characterised in that the support structure is in the form of an elongated, vertically-disposed panel.
A machine as claimed in claim 27 or 28 characterised in that the structure is floor-mounted and the height of the structure is such that an operator can reach all processing units while standing on the floor.
A machine as claimed in any of claims 27 to 29 characterised in that the winder infeed guide is disposed vertically above winder unit.
A thread processing machine, for example a false twist texturing machine, comprising a support structure and thread processing elements carried by the support structure at respective locations spaced along a predetermined thread path which leads to a winding device
characterised in that
the thread path is so arranged that the thread is passed from each processing element to the next and finally to the winding unit without intervening passive guiding means and/or feed nips.
A thread processing machine, for example a false twist texturing machine, comprising a support structure and thread processing elements carried by the support structure at respective locations spaced along a predetermined thread path which leads to a winding device
characterised in that
processing elements are disposed at positions along the yarn path at which the thread is to be diverted from a straight line, each such processing element taking up thread along a line aligned with the upstream portion of the thread path and delivering thread along a line aligned with the downstream portion of the thread path.
A machine as claimed in claim 31 or 32 characterised in that the upstream and downstream portions of the thread path are arranged at right angles to each other.
A machine as claimed in claim 33 characterised in that one such processing element is arranged at each corner of a rectangular thread path.
A machine as claimed in any of claims 31 to 34 characterised in that additional processing elements are arranged on at least one straight portion of the thread path.
A high speed thread processing machine comprising thread processing elements and a winder
characterised by
an additional take-up adapted to receive thread processed at relatively low speed and a control means operable to transfer the thread to the winder when the machine is operating at a predetermined minimum speed.
A high speed thread processing machine comprising thread processing elements and a winder
characterised by thread forwarding means on the thread path upstream from the winder and arranged to isolate thread tension in the path region leading to the winder from thread tension in the path region upstream from the said forwarding means.
A machine in which each processing means relative to one thread process position is driven by a control system through suitable drives using feed back employing suitable sensors, e.g. speed sensors, temperature sensors, yarn tension sensors, in respect to predetermined settings and / or on line process control.
A machine as claimed in claim 38 characterised in that the position can be started, run and stopped independently.
A godet module comprising a hollow cylindrical godet element and a drive motor coupled to the godet element to rotate it about the longitudinal axis of the motor shaft characterised by separating means to separate the operating environment of the motor from the operating environment of the godet element.
A module as claimed in claim 40 characterised in that the separating means comprises a hollow elongate member that projects into the interior of the godet element.
A module as claimed in claim 41 characterised in that the elongate member has a closed end within the godet element and the motor shaft extends through the closed end of the elongate element.
A module as claimed in any one of claims 40 to 42 characterised in that the separating means is in the form of a tube.
A godet comprising a hollow cylindrical godet element and a drive motor coupled to the godet element to rotate it about the longitudinal axis of the motor shaft
characterised in that the godet element is directly mounted on the motor shaft and in that the motor comprises bearings so that the bearings for the motor also provide bearings for the godet element.