Package conveying system

Abstract: Roving packages are fed into the creel of a spinning frame by movements along a path at right angle to the machine longitudinal axis and are moved out of the creel by movement along another path at right angles to the machine longitudinal axis, the two paths being joined by a path extending along the machine.

Description: This invention relates to a spinning mill installation for moving packages or package carriers in and adjacent a spinning machine according to the pre-clause of claim 1, in particular a ring spinning machine. The invention is intended particularly for use in combination with an overhead conveyor, for example of the type shown in German patent specification No. 3601832. EP-A-307806 (published 22 March 1989) discloses a system for transporting roving bobbins in cyclic manner between a roving process, a spinning process and a residual roving clear-off process, in which the roving bobbins are transported while suspended from a carrier along a main rail arranged to form an endless loop and working rails branched from the main rail, such as roving frame rail, a spinning frame rail or a residual roving clear-off rail. The carrier is detachably connected to a tractor and driven thereby. A means is provided representing the respective frame address or the respective working rail address. This means is arranged on the main rail and is detected by a sensor mounted on the tractor. A station is arranged at least in the inlet areas of the roving and spinning processes, respectively, for transmitting a command issued from a central control unit supervising the system to the tractor, this command being compiled in accordance with information received regarding the conditions of the tractor and of the respective frames and working rails and including information containing the frame address and/or the working rail address to which the carrier should be transported. EP-A-307806 therefore discloses a centrally controlled system for directing feed packages to spinning machines and (possibly) returning empty tubes to a preparatory machine. This specification representing the closest prior art does not, however, contain any proposals regarding control of operations performed in the region of the spinning machine itself. It is well known that a group of ring spinning machines in a spinning mill can be supplied with packages of roving via a transport system in the form of a rail network (in particular in the form of an overhead rail network). For this purpose it is known to load the roving packages onto carriers which are assembled to form a "train" for transport via the transporting system. A train of this sort can be moved directly into the creel of a ring spinning machine (for example in accordance with the principle set out in United States patent specification No. 3828682), or the train can be caused to travel around the ring spinning machine while roving packages are transferred as necessary from the train into the creel (for example in accordance with the principle set out in German specification No. 3601832). As long as spinning mill personnel is available at the time of a package change in the creel (at least for the purpose of monitoring the changeover procedure), various compromises can be envisaged with regard to the control system for the complete installation. However, this no longer applies when the installation is intended to run completely automatically, for example during an unmanned night shift or during weekend working. The designer of the automated installation must assume that the package changeover procedure can be completed without human intervention and he must provide a corresponding control system. In designing a system of this type, a basic decision has to be made at an early stage, namely where will the "intelligence" (information processing capacity) be provided in the system. It would be possible, for example to provide each train (each vehicle) with intelligence, so that the train is able to carry out in a self-sufficient manner those "transport tasks" allocated to it. A solution of this type is, however, not attractive for transport of roving packages via a rail network to a group of ring spinning machines because many trains have to be provided even in a relatively small installation. The costs of the computing capacity and the maintenance of the system would therefore be relatively high if, for example, each train had to be provided with its own individual microprocessor. In a further possibility, all of the intelligence of the system is located in a central computer which then controls the complete transport system including movements within the machines. The computing capacity of an "all knowing" processor of this kind would however have to be very large and the transmission of the required data from all parts of the installation to the central computer would raise considerable problems in an installation linking roving frames with ring spinning machines. In EP-A-311862 (published 19 April 1989) and also in EP-A-329965 (published 30 August 1989), we have described a conveying system for packages of spinnable strand (roving or sliver) with a path for the packages or their carriers extending longitudinally of the spinning machine between the rows of spinning positions. Both these applications also show a transport means for transporting packages to a spinning machine and transporting empty package carriers from the spinning machine. It is an object of the present invention to further develop the system shown in the above-mentioned EP-A-307 806. This object is achieved by providing an installation having the features set out in claim 1. Advantageous further developments are given by claims 2 to 20. Embodiments of the invention will now be explained in further detail with the aid of the Figures of the drawings, in which: Figure 1 shows a schematic plan view of a spinning mill installation which is to be controlled in accordance with of the invention, Figure 2 shows a schematic representation of a control arrangement for the installation in accordance with Figure 1, Figure 3 shows a perspective schematic representation of part of the creel of a ring spinning machine with a central conveying path for the empty package carriers, Figure 4 shows a plan view of a first embodiment of the invention, Figure 5 shows a schematic plan view of the junction region between a ring spinning machine and a transport system serving that machine to illustrate the basic features of a second embodiment of the invention, Figure 6 shows schematic a plan view of a modification of the arrangement according to Figure 3, Figure 7 shows a schematic plan view of the creel of a ring spinning machine together with a package handling robot and package transport train, and Figure 7A shows a detail of a sensor suitable for this robot, Figure 8 shows a detail from the installation in accordance with Figure 5, Figure 9 shows a schematic isometric representation of a train and a drive means for moving the train within the transport network, Figure 10 shows a schematic representation in section of a part of the train together with a second drive means for moving the train in the region of a ring spinning machine, Figure 11 shows a partial side view of a belt serving as a take-up path located near the central longitudinal plane of the machine and having receiving means mounted thereon for taking up empty package carriers comprising suspension elements for package tubes, Figure 12 illustrates the arrangement shown in Figure 11 viewed from the right-hand side of that Figure but without the empty package carrier shown in Fig.11, Figure 13 shows a vertical section through the train for transporting package carriers according to Fig.11, Figure 14 shows a further plan view of the junction region between the transport network and the ring spinning machine with an arrangement of sensors suitable for a control system in accordance with the invention, Figure 15 shows a diagrammatic plan view of an arrangment of sensors suitable for controlling return of empty package carriers from a central conveyor path within the machine to a transport unit for transporting those packages back into the transport network, and Figure 16 shows a signal diagram for further explanation of the arrangements shown in Figures 14 and 15. Figure 1 shows a mill installation with a single roving frame F and four ring spinning machines RS1, RS2, RS3 and RS4, any one of which is designated in the subsequent description as machine RS. A practical mill installation comprises several roving frames and a large number (for example 10 to 20) of ring spinning machines. The principles proposed by this invention are, however, independent of the size of the mill and in a very large installation the machines could be grouped so that each group of ring spinning machines is served by packages from a predetermined roving frame as illustrated in Figure 1. In the example shown in Figure 1, the roving frame F is connected with all four ring spinning machines via a rail network SN for transport of roving packages. This network is indicated only diagrammatically but in any event it will normally include a buffer section P. The layout has already been illustrated in principle in US patent specification No. 3828682 and more modern variants of this arrangement have been shown in EP-A-311995 and 323400. Figure 1 and the patent specifications mentioned immediately above are concerned primarily with questions of material flow. In this connection, two essential components of the material flow should be mentioned, namely flow of roving packages in the direction from the roving frame to the ring spinning machine and the flow of empty package carriers in the direction ring spinning machine to the roving frame. A complete roving package can be considered to comprise a package carrier and a body of windings of spinnable strand, the latter being processed in the spinning machine to produce a yarn. In order to assure continuity of the process considered over all, sufficient empty package carriers must be available in the complete installation to enable continuation of the strand (roving) formation process in the roving frame at the time roving packages are being delivered to the individual ring spinning machines. The element or elements constituting a "package carrier" depend to some extent on the design of the system, as will be explained with reference to Figures 11 to 13. Figure 2 illustrates the same installation considered this time with regard to the flow of signals and data processing rather than in terms of material flow. In accordance with Figure 2, a control unit AS is provided for the transport network, and an individual control unit is provided for each individual machine. The control unit for the roving frame is indicated at SF and those of the ring spinning machines are indicated by the reference symbols RSS1, RSS2, RSS3 and RSS4, generally indicated hereinafter as "RSS". The control units of the individual machines are connected with the network control unit AS for exchange of data in both directions. Various processes have been described in the literature for delivery of roving packages to the operating positions in the creel of a ring spinning machine. For example, it has been proposed (in European patent specification Nos. 310870 and 310871) to provide a transfer carriage which runs along the machine and transfers roving packages from a suspension conveyor into the machine creel. Similar ideas have been put forward in US patent specifiction No. 4799353. This invention is not limited to any particular kind of operation for transferring packages into the creel. However, the preferred arrangement for effecting such transfer has been described in our own various patent specifications referred to in this specification. A system operating in accordance with those specifications will be assumed in the following description and will be discussed first in broad outline with reference to Fig. 3. Figure 3 shows a diagrammatic representation of a portion of the creel of a ring spinning machine. The creel comprises vertical posts 530 supporting transverse beams 532 which in turn carry short rail sections 16 each forming a path transverse to the length of the machine. When the machine is in operation, each rail section 16 normally carries three package carriers 360 supporting roving packages at various stages of unwinding. Thus, the packages 13' at the outer end of the rail section 16 are reserve packages which normally have not yet been set in use to supply spinnable strand to the spinning positions 21, 21' associated with the respective rail section 16. The other two packages 18, 19 carried by a rail section 16 will be working (or operating) packages supplying respective strands 22 to the spinning positions 21, 21'. The innermost package 19 on a rail section 16 should be in a more advanced stage of unwinding than the other operating package 18 so that the innermost package 19 is emptied first and becomes simply an empty support tube as indicated with the reference numberal 11. When the innermost package 19 has been unwound to the stage of an empty tube 11, all three package carriers 360 on the rail section 16 can be moved inwardly. The empty tube 11 is thereby moved onto a conveyor belt diagrammatically indicated at 15 and representing a central conveying path of the machine. The previously mentioned reserve package 13' is then used to supply strand to the spinning position previously supplied from the innermost package 19 (which has now being reduced to an empty tube 11 to be carried away on the belt 15). Figure 3 also indicates diagrammatically a train 38 carrying full packages 13 to replace reserve packages 13' which have been moved inwardly of the creel into an operating position as immediately described above. Furthermore, Figure 3 shows diagrammatically a return device 8 by means of which empty tubes 11 can be moved from the belt 15 outwardly at right angles to the central longitudinal plane 6 of the machine for return to the train 38 (as indicated by the empty tube 11 shown in dotted lines in Figure 3) when the train 38 has been emptied of full packages 13. Figure 4 shows schematically a first embodiment according to this invention. The spinning machine is indicated with the reference numeral RS, only one end portion of the machine being indicated by the reference symbol 9. The machine has a central conveying path 15. The spinning positions (not shown) have associated transverse paths 16 and an additional transverse path 16' is provided for return of empty package carriers. A transport rail with two straight main rails 514, 516 and a curved rail section W extends around the spinning machine RS and forms a guide path for a transport means, e.g. a train 38, which serves for delivery of packages from a roving frame and for carrying empty package carriers back to roving frame. The outer end of each transverse path 16 or 16' forms a "transfer interface" as schematically illustrated with the box having the reference numeral SS in Figure 4. At least within this group of transfer interfaces SS, the paths 16,16' and 15 form an autonomously-operating and autonomously controlled conveying system for packages and package carriers taken over from the main transport network (represented in this case by the rails 514, 516 with the train 38). The control of this autonomously-operating system is effected by the control system RSS of the machine RS, as indicated by the dotted line signal connection between this control RSS and the conveying system 16,16',15 in Figure 4. This signal connection operates with appropriate sensors and actuating devices (not shown in Figure 4, but subsequently described with reference to further figures) within the conveying system in order to effect controlled movements of the individual packages or package carriers within the autonomously-operating system. The main transport network is controlled from a control device AS (Fig. 2). It is, however, necessary to provide transfer means to effect transfer of packages or carriers between the main transport network and the autonomously-operating conveying system of the ring spinning machine RS. For this purpose, the following possibilities can be provided in a system according to Figure 4: 1. An individual switching device can be provided at each end of a transverse path 16, or 16', this switching device being adapted to create a temporary connection between the respective transverse path and the transport train 38, 2. a travelling switching device can move around the machine RS (for example with the transport train 38) in order to create selective connections between the train and a selected transverse path, or 3. a package or package carrier handling device (a handling robot) can travel around the machine in order to effect transfer at a selected interface SS. The handling device could, for example, be integrated into the train 38 but could also be provided in association with the machine RS and could be controlled by the machine control system RSS in Figure 4. In the arrangement illustrated in Figure 4, it is assumed that the interface between the autonomously-operating conveying system of the machine and the transport network lies at the ends of the transverse paths of the machine itself. This is not, however, essential. An alternative arrangement (in which a rail section directly associated with the ring spinning machine to carry the transport train 38 is integrated into the autonomously-operating system of the ring spinning machine itself) will now be described in outline with reference to Figures 5. Figure 5 shows a rail 201 forming part of a transport network and a conveying system associated with a particular ring spinning machine RS. The rail 201 is connected with the conveying system by means of a points unit 202. The conveying system associated with the ring spinning machine RS comprises in this case a spur-rail 203 on which roving packages are delivered to the machine and empty tubes are carried away therefrom. The conveying system associated with the ring spinning machine comprises furthermore a closed circulation path 205 connectable by non-illustrated switching means with transverse conveying paths 16 in the creel. A points unit 204 is provided between the spur-rail 203 and the circulation path 205. As in the case of the previous embodiment, the conveying system in the machine further comprises a transport belt 15 for taking up empty tubes from the transverse conveying paths 16, only two of which are indicated by way of example in Figure 5. A return station for returning empty tubes to the transport means, for example, in the form of a transport train, is indicated at 8 and connects the transport belt 15 with the circulation path 205. The ring spinning machine RS in Figure 5 is provided with an autonomously-operating control system, such as the electronic control unit RSS in Figure 4. The control interface between the control system of a ring spinning machine and that of the network preferably lies at the points unit 202 or at any rate at the points unit 204. That is, this control interface preferably lies on or at a transport section (spur-rail 203 or circulation path 205) leading only to the relevant machine (in this case the ring spinning machine RS). The "control interface" referred to here is a location in the network at which control over movements of a transport unit or elements carried thereby is passed from one control means to another. Means must be provided for signal exchange with both control systems (that of the network and also that of the ring spinning machine) so that the "transfer" of a transport unit (a train) between the two control systems can be monitored and/or registered by both control systems. Suitable arrangements will be described subsequently. However, it is not necessary to feed the creel of a single ring spinning machine over only one single points unit. A second points position, with a respective spur-rail, could be provided in association with the other machine side (as indicated by a dotted line in Figure 5). The delivery path 205 is then not necessarily designed as a circulation path. In principle, a further transport rail (similar to the rail 201) could be provided at the other end of the machine RS and could be connected with one or both machine sides over at least one spur-rail. The disadvantage of complication in the layout of the installation can in some circumstances be compensated by advantages associated with the possibility of very rapid delivery of packages to the creel of the machine. A plurality of sensors are provided to monitor the transport system taken as a whole. A sensor 211 is provided immediately adjacent to the points unit 202 to register movement of a package train onto the spur-rail 203 from the transport network and return of a train from the spur-rail 203 into the transport network. A sensor 212 can be provided in the immediate neighbourhood of the points unit 204 to register movement of a train onto the circulation path 205 or departure of a train from that circulation path. A further sensor 213 can be provided at a position on the circulation path 205 representing a parking or a stand-by position for the train and a further sensor 204 can be provided at the tube return station 8 for purposes to be described with reference to other Figures. For purposes of a general description of the operation of the system, it will be assumed that a plurality of roving packages are assembled into one transport unit (generally referred to as a "train") and are transported together within this unit to the ring spinning machine. There can be any desired number of roving packages in a train, but this number is preferably so selected that it represents a predetermined fraction of the number of spinning positions in a spinning preparation machine such as a roving frame. In order to move a train from the transport network (i.e. from the rail 201) into the conveying region of the ring spinning machine in a direction indicated by the arrow A in Figure 5, the points unit 202 and 204 must first be set in the appropriate condition and the ring spinning machine RS must be in an operating condition such that packages from the train can be taken up within the creel. The points unit 202 and 204 are set by the control system allocated thereto as will subsequently be described with reference to other Figures. The arrival of the train, and the number of roving packages carried thereby, is monitored by the sensor 211. A drive means (not illustrated in Figure 5) for moving the train along the circulation path 205 in the direction of the arrow B is then set in operation. Passage of the train through the points unit 204 is registered by the sensor 212, and points unit 204 is then reset so that the circulation path 205 is closed and separated from the spur-rail 203. The newly-arrived train moves then into the parking or stand-by position, and this is registered by the sensor 213. During movement of the train between the points unit 204 and the parking position, roving packages may have been transferred from the train to the creel. Accordingly, the sensor 213 is adapted to register the number of roving packages remaining on the train when it arrives in the parking position. In the (abnormal) event that all roving packages have already been transferred to the creel before the arrival of the train in the parking position, the train will immediatly be re-loaded with empty tubes by way of the return station 8, the points unit 204 will be reset so as to connect the circulation path 205 once again with the spur-rail 203, and the train now loaded with empty tubes will be returned into the transport network, i.e. to rail 201. In the more normal case, arrival of the train in the parking position and counting of the roving packages remaining thereon will be followed by a first circulation of the ring spinning machine RS along the path 205 in the direction of the arrow B. Roving packages can be transferred into the creel at the required positions along this circulation path. The number of packages remaining on the train can again be counted at the sensor 212. By means of counting operations at both the sensors 212 and 213, the number of roving packages delivered on each machine side can be established and can be indicated to the control system of the machine. In any event, after each complete circulation, the number of remaining roving packages is determined by the sensor 213. The individual circulations can be carried out at intervals adjustable between zero and fifty hours. The period of these intervals can advantageously be adjusted in dependence upon the demand for new material in the creel. However, a basic interval can be defined and this basic interval can apply until the number of roving packages still carried by the train falls below a level representing the average demand per circulation. The interval can then be shortened. When the number of roving packages carried by the train drops below a predetermined level, the parking interval can be eliminated and the train can immediately be sent in a further circulation as soon as the number of packages remaining thereon has been established by the sensor 203. When the train is empty, the conveyor belt 15 is set in operation in the direction of the arrow C in order to convey the empty tubes successively to the return station 8. The arrival of the empty tubes at that station is detected by the sensor 214. The return station conveys the individual empty tubes back to the train. When the train has been re-loaded with a number of empty tubes corresponding to the number of roving packages carried by the train at the time of its arrival, the points unit 204 is reset and a signal is sent to the control device AS (Fig. 2) for the network. The train is moved in the direction of the arrow D out of the conveying region associated with the individual ring spinning machine back into the transport network on rail 201. The machine RS can call for a new train of roving packages from the network. The present application is not concerned with the design or operation of a handling robot for handling packages or package carriers at the machine. A detailed description of such a robot can be found in EP-A-394708. A part of that description will however be repeated here in order to demonstrate the interrelationship of the robot with the package or package carrier moving system provided in and controlled by the machine. The control system now to be described differs slightly from that described with reference to Fig. 5 in that control functions are "delegated" to a control unit 44 (Fig. 7) on a package handling robot. In Figure 6, reference numeral 13 indicates full packages for delivery to spinning positions 21, 21', and empty tubes are indicated with the reference numberal 11. The ring spinning machine has at one end a drive head 9 and at the other end an end head 10, there being two rows 7 of spinning positions 21, 21' on respective machine sides. The longitudinal central axis of the spinning machine is indicated with the reference numeral 6. In this case, a single main rail 14 extends along both machine sides and around the end head 10, and one or more package transport trains 38 can be arranged on this transport rail. Each train 38 comprises compartments 36 joined together by links at 45 such that each compartment 36 can carry a package 13 or an empty tube 11. The link joints between the compartments 36 are required so that each package transport train 38 can travel around curved rail sections, for example at the end head 10. In the illustration according to Figure 6, a package transport train 38 arriving from the transport network and loaded with packages 13 is arriving at the upper left part of the Figure, travelling in the direction of the arrow Z. The train 38 can be stopped first in a stand-by position until there is a need for replacement (at one or more of the spinning positions 21, 21') of a reserve package 13' which has been converted to an operating package 18 or 19 as will be further described subsequently. The train 38 is then moved under the control of an electronic control unit RSS within the machine itself (for example in the end head 9) to the region of a transverse support 16 at which a package changeover is required. There, a package 13 is unloaded from the train into the creel, for example by means of a travelling transfer carriage which is not shown in Figure 6. As soon as at least several, and preferably all, compartments 36 of the transport train have been emptied of full packages, the train is moved under the control of the unit RSS to one of the return stations 8 provided at the ends of the rows 7 of spinning positions. The stations 8 comprise transverse supports 16' similar to the transverse supports 16 but designed for conveyance of empty tubes 11 outwardly from the central conveying path 15 towards the main rail 14. Loading of the empty train 38 is carried out in that the compartments 36 are successively brought into alignment with one of the transverse supports 16' whereby in each case the first available empty tube 11 is replaced in the empty train compartment. The train 38 is then moved through one step in order to bring the next compartment 36 into alignment with the relevant support 16'. Preferably, at the time of loading of the first mentioned empty tube 11 into a compartment 36, the next empty tube 11 is moved to the return station 8 and therefore is available for loading of the next empty compartment 36 when that compartment is brought into alignment with the support 16'. As soon as the train 38 has been re-loaded with empty carriers, it is returned to the transport network, as indicated in Figure 6 at the upper right-hand corner by the arrow P. In accordance with Figure 7, a ring spinning machine comprises similarly formed spinning positions 21, 21' (schematically illustrated) of uniform gauge. In front of the spinning positions, the rail 14 extends parallel to the longitudinal direction of the machine. Carriages 36 are suspended from this rail by means of rollers 35 and are arranged at uniform spacing along the rail. The individual carriages 36 are joined by means of a rod 37 (indicated only schematically) to form a package transport train or trolley 38. Each carriage 36 carries below the rail 14 a tube 11 suspended vertically therefrom and wound with roving 22 to form a package 13. The rod 37 also carries a motor 39 which engages the rail 14 by way of a friction wheel 40. The current supply to the motor 39 is effected in a manner indicated only schematically by way of a current take-up 41 which engages a bus 42 extending along the machine. The bus is energised with a suitable supply voltage. The motor 39 is connected by way of a control lead 43 (indicated in dotted lines) to an electronic control 44. The control lead 43 passes in manner subsequently to be described via contacts 77, 78 from the train 38 onto a tube transfer carriage 20. By way of the same lead, further electrical assemblies, which will also be described subsequently, are also connected to the electronic control unit. By way of this control lead 43, the motor 39 can be selectively switched on and off. The rod 37 is provided with joints 45 having vertical pivot axes in order to enable a movement of the train around curved sections of the rail 14. Behind the spinning positions 21, 21' there is an empty tube conveying means 15 in the form of a conveyor belt that runs over divertor rolls 46 indicated by dotted lines. This belt can be moved in a stepwise manner in the direction of the arrow f. Empty tube support elements 47 are located on the conveyor belt 15 with uniform spacing thereon. Empty tubes 11 can be suspended from these elements 47 with vertically disposed longitudinal axes of the tubes in order to be conveyed to an empty tube return station 8. This station removes tubes 11 arriving at an end of the conveyor belt 15 from their carrier elements 47 and conveys them back to the carriages 36 of the transport train 38, which in the meantime has been emptied of its full packages (this is indicated by the dotted arrow 49). The empty tube return station 8 is served in the illustrated embodiment by the same transfer carriage 20 which moves the packages 13, in a manner to be subsequently described, onto the empty tube conveyor 15. The movement of the conveyor belt 15 is discontinuous so that the belt can be stopped temporarily at any desired position. The spinning positions are arranged in pairs 21, 21' with the positions of a pair being arranged next to each other. For each pair, there is a respective tranverse support 16 arranged between the adjacent spinning positions of the pair and preferably above them. The transverse supports 16 extend parallel to each other in a creel. Each transverse support 16 carries in a row extending from the rail 14 to the conveyor belt 15 in the following sequence: a reserve package 13' fully wound with roving 22, a first working tube 18 completely or partly wound with roving 22, and a second working package 19 partly wound with roving 22 or empty (unwound). These packages are arranged at uniform spacing along the respective transverse support 16. Preferably, the packages 13', 18, 19 are mounted from below on the transverse support 16 by way of suitable support elements. Between the rail 14 and the conveyor 15 there is a further pair of rails 50 extending parallel to the machine longitudinal direction 23. A tube transfer carriage 20 is arranged for movement in the longitudinal direction 23 of the machine on these rails 50, for example by means of rollers. The carriage 20 can for example be supported by means of rollers 51 on the rail pair 50. Two rods 52 extend from the part 20" of the carriage 20 to the front portion 20' which is arranged above one of the transverse supports 16. The rods 52 carry fork-shaped tube gripping means 29 which can be brought into gripping engagement with the packages 13', 18, 19 below the front portion 20" (being illustrated in this condition). The rods 52 engage in shifting chambers 12 of the rearwood portion 20' of the carriage 20 and are biased by springs 17 in the direction of the front portion 20' of the carriage 20. Electromagnets 53, which are also controlled by the electronic control unit 44 (dotted line) when suitably supplied with current, enable withdrawal of the tube gripping means (previously brought into engagement with the tubes of the packages 13', 18, 19) against the force of the spring 17 so that these means are no longer in engagement with the relevant tubes. An entrainment means 54 extends forwardly from the front portion 20" of the carriage 20 and carries slidably an entrainment rod 56 extending parallel to the transverse supports 16 in a transverse bore 55. Normally, the entrainment rod 56 is extended by a compression spring 57 into the entrainment position apparent from Figure 7, in which it extends in front of entrainment abutments 58 secured to the rod 37. Each abutment 58 is associated with a respective carriage 36 being positioned exactly relative to its associated carriage. An electromagnet 59 which is also connected to the electronic control unit 44 (dotted line) when suitably supplied with current draws the entrainment rod 56 against the bias generated by the spring 57 through a distance such that the entrainment rod 56 comes out of engagement with the corresponding entrainment abutment 58. A transverse moving device 31 is provided on the rear portion 20' of the carriage 20. This device comprises transverse shifting rolls 60 which can also be suitably driven under the control of the electronic control unit 44 (dotted line) and which are rotatably mounted on the rearward portion 20'. The device further comprises a transverse carriage 61 arranged between the rolls 60 and movable thereon in the transverse direction. The carriage 61 comprises the above-mentioned shifting chambers 12 and the rods 52 which are reciprocable in the longitudinal direction 23 of the machine. A lifting and lowering means 32 (indicated in dotted lines) can also be arranged on the transverse carriage 61. The rods 32 and the tube gripping means 29 connected therewith are liftable and lowerable within predetermined limits not only reciprocably in the direction of the arrow 62 but also in directions at right angles to the plane of the drawing. The illustrated ring spinning machine operates in the following manner: In normal operation, each transverse support 16 carries in a row one full reserve package 13', a completely or partially full working package 18 and partially full or empty (unwound) working package 19. As indicated in the region of the front portion 20" of the carriage 20 in Figure 7, the roving 22 is guided from the operating package 19 to the spinning position 21 located to the right of the transverse support 16, while the roving 22 from the middle operating package 18 is guided to the spinning position 21' provided to the left of the transverse support 16. This guidance of the roving 22 changes over on the occasion of each of the subsequently described tube shifing operations. The working packages 19 carry on average approximately half as much material as the working packages 18 so that when a working package 19 has been unwound the associated second working package 18 is still approximately half full. If one of the working packages 19 has been emptied then the transfer carriage 20 can be moved along the rail path 50 to the relevant transverse support 16 under the control of the electronic control unit 44.This movement is effected by setting the motor 39 in operation so that the transport train 38 is moved along rail 14 while the transfer carriage 20 is carried along by way of the respective abutment 58 and the entrainment rod 56. A light barrier 63 is mounted on the entrainment member 54 and a light beam 64 from this barrier works together with a reflector 65 provided on every second spinning position 21'. In this way, the electronic control unit 44 receives a signal via the control lead, indicated in dotted lines, on the basis of which the motor 39 can be stopped. The tube transfer carriage 20 is then located in an exactly determined position for the required tube shifting operation. The electronic control unit 44 now causes movement of the rods 52 outwardly so that the tube gripping means 29 engage the tubes of the packages 13', 18, 19 below the front portion 20" of the carriage 20 and by way of the lifting and lowering means 32 cause a slight lifting or lowering so that they are released from the associated transverse support 16. A further tube gripping means 19', which extends to a position below the rail 14, and which is also connected with the rods 52, grips and moves in a corresponding manner the fully wound package 13 which is aligned with the relevant transverse support 16. This package 13 is thereby released from the associated suspended carriage 36. Before this operation is carried out, the conveyor belt 15 must have been moved in the direction of the arrow f to a position such that (in addition to the tube gripping means 29, 29') a vacant tube support element 47 is located in alignment with the relevant transverse support 16. When considering the illustration in Figure 7, therefore, the conveyor belt 15 must be moved through one pitch of the support elements to enable this condition to be achieved. By means of the electronic control unit 44, the transverse carriage 61 is now moved through one tube pitch in the direction of the arrow 62 drawn in full lines. By this means, the empty (unwound) tube 11 of the previous working package 19, possibly following an additional operation of the lifting and lowering means 32, is transferred to the adjoining tube support element 47. Simultaneously, the now half full working package 18 is shifted into the position vacated by the removed tube 11, the reserve package 13' is shifted into the position vacated by the working package 18 and the fully wound package 13 is shifted into the position vacated by the former reserve package 13'. The rods 32 are thereupon withdrawn by energization of the electromagnets 53 and the transverse carriage 61 is moved back in the direction of the arrow 62 (drawn in dotted lines) into its starting position. A package change-over has thus been completed. The motor 39 is now set in operation again by the electronic control unit 44. Since the package 13 aligned with the front portion 20" of the carriage 20 has been transferred onto the transverse support 16, there is no longer a tube on the associated suspended carriage 36. Thus, a spring biased feeler 66 which is pivotably mounted in the front portion 20" of the carriage 20, can be so turned in the direction of the arrow indicated on the feeler 66 that a contact 67 is closed. This contact is also connected with the electronic control unit 44 by a control lead indicated by dotted lines. In this way, the extension of the entrainment rod 56 outwardly is temporarily blocked. With the motor 39 in operation, the transport train 38 therefore moves at first independently of the carriage 20 in the direction of the arrow P. Only when the next package of the transport train 38 passes into the region of the front portion 20" of the carriage 20, does the feeler 66 again come into contact with the roving 22 so that the contact 67 reopened. The electronic control unit 44 then sends a switching-off signal for the electromagnets 59 whereupon the spring 57 can reextend the entrainment rod 56 so that it passes into a position in front of the third abutment 58 considered from the right in Figure 7. Immediately afterwards, this entrainment abutment 58 comes into engagement with the entrainment rod 56 and the tube transfer carriage 20 is now carried along with the train as far as the next pair of spinning positions 21, 21' where a transfer operation is to be carried out. This can be a pair of spinning positions at which on the basis of corresponding arrangements one of the working packages 19 has just become empty. The already described operation is then repeated in the same manner. In this manner, the tube transfer carriage is moved from spinning position pair to spinning position pair until all of the packages 13 wound with roving 22 and carried by this transport train 38 have been used up (transferred into the creel). Then, at the end of the machine as indicated at 49, the empty tubes 11 are successively suspended onto the emptied carriages 36 of the transport train 38, whereupon the train 38 can be returned to the transport network and from there to a roving frame where it is again loaded with fully wound tubes (packages). For the purposes of returning the empty tubes 11 to the train 38, the tube transfer carriage 20 can again be used. For this purpose, the shifting mechanism on the carriage is operated in the reverse sense to that described to move empty tubes along an additional (return) rail at a train re-loading station. The connection of the motor 39 by way of the control lead 43 to the electronic control unit 44 can be ensured in practice by arranging an electrical control contact 77 in the end portion of the entrainment rod 56. The control contact 77 comes in to electrically conducting engagement with an opposing contact 78 secured to the entrainment abutment when the extended entrainment rod 56 comes into engagement with the associated entrainment abutment 53. By way of this electrically conducting engagement, an electrical connection (which is not illustrated in detail in Figure 7) is effected between the electronic control unit 44 and the electrical motor 39 on the basis of which the electrical motor 39 receives the required stop and start signals at the right instant. The individual opposing contacts 78 which are mounted on respective entrainment abutment 58 are connected by non-illustrated leads within the rod 37 to motor 39. In an alternative embodiment (not shown in Figure 7), the package transport train 38 is not self-driven. The tube transfer carriage 20 can carry along the package transport train 38 by means of a friction roll or a gear wheel. It is then possible to arrange for movement of the tube transfer carriage 20 relative to the package transport train 38. A motor (not shown) on the carriage 20 drives the friction roll or the gear wheel and can operate as a servomotor. For re-loading of the train a sensor can be provided to detect whether the holder on the train is carrying for example a carrier 360 as shown in Figure 3. If not, a re-load instruction can be provided to the shifting mechanism, on the carriage, which shifts at least one empty tube along the return rail at the re-loading station and onto the train. Thereupon, the motor moves the package transport train 38 through one position and the next empty tube 11 can be conveyed back onto the package transport train 38. In normal operation, one strand 22 is withdrawn from each of the working packages and these strands are guided via a guide rod (not shown) which is provided with grooves. If the inner package becomes empty, the strand 22 from the reserve, fully wound package 13' is laid by the operator or automatically in the groove of the guide rod. The working packages now remain in use over a relatively long period in the course of which they are however moved towards the central plane of the machine. An initiating means for causing the carriage to perform a package shifting operation, can comprise a sensor, which has a sensing range corresponding to the tube length, to respond to the presence of the strand 22 leading to the guide rod. A further possibility lies in the use of a sensor which is directed to the presence of the strand 22 on the inner working package. Another form of a sensing means, providing the initiating means, involves sensors 120 (Figure 7A) which preferably are arranged in pairs to detect the diameter of the body of roving windings on the inner package (that is the package nearest the central plane of the machine). An effective operating procedure lies in moving the tube transfer carriage 20 alone, without the package transport train 38, along the rails and determining by means of the above-mentioned sensors those rails 16 at which a package change is required. This data is stored in the electronic control unit 44 and transmitted if necessary to a central machine control. In accordance with these signals, a package transport train 38 can be directed to the ring spinning machine from the transport network between the ring spinning section and the roving frame section. In accordance with a further possible embodiment, the tube transfer carriage 20 can couple to the front end of the package transport train 38 at the first creel rail 16 at which a transfer operation is required (for example by means of a non-illustrated entrainment lever, or by means of a gear wheel). Fully wound packages can then be directed from the package transport train 38 successively onto the creel rails 16 at which a change operation is required and which have previously been registered and stored in the databank of the electronic control unit 44 and/or the machine. When the last fully wound package 13 is reached on the package transport train 38, the tube transfer carriage 20 can again transmit a signal to the machine control RSS indicating that the train 38 no longer carries any fully wound tubes. The re-loading operation can then be initiated in accordance with which the tube transfer carriage 20 is guided to the rail serving for the re-loading operation and the conveyor belt 15 is set in operation. In order to avoid the necessity to set the package transport train 38 into operation each time and to align it each time with a creel rail 16 at which a package change operation is required, another operation can be used. In accordance with this operation, the package transport train 38 (loaded for example with sixty fully wound packagess 13) is guided by means of suitable switching link out of the transport network onto the rail 14 and is positioned along the first sixty creel rails 16. In accordance with the data stored in the electronic control unit 44, the tube transfer carriage 20 now transfers from the package transport train 38 those fully wound packages 13 which lie in alignment with rails 16 at which a package change operation is required. As soon as this section of sixty creel rails 16 has been served, the tube transfer carriage 20 can move the package transport train 38 to the next following section. The package transport train 38 now no longer contains a continuous row of fully wound packages 13. However, this is not a basic disadvantage since a sensor of the tube transfer carriage 20 can establish automatically the positions on the package transport train 38 at which fully wound packages 13 are still present. This can be effected as the carriage 20 moves past the train 38. The carriage 20 then serves all rails 16 within this section which already have a fully wound package 13 aligned with them and which are in need of a package change operation. In the event that a rail 16 in need of a package change operation is aligned with an empty space in the package transport train 38, the tube transfer carriage 20 can cause continued movement of the package transport train 38 (for example by means of a gear wheel) until a fully wound package 13 comes into alignment with the relevant rail 16. The description of Fig. 7 up to this point has assumed that the most desirable form of package change operation is based upon a so-called random changing procedure. In accordance with this procedure, the individual transverse supports in the creel are served individually and without any preset sequence or any preset relationship to any other transverse support (but merely dependent upon the sensing of the need for a package changing operation and the availability of a replacement reserve package). There is however an alternative procedure (known as a block changing procedure) in which a complete section of neighbouring transverse supports are served by one package transport train while that train remains stationary in alignment with the relevant section. This mode of operation is only possible if the innermost working packages (those which in the course of the package changing operation will be transferred onto the removal conveyor in a central region of the machine) have all been unwound to a predetermined extent. This minimum unwinding is such that all of these innermost packages can be taken up by the removal conveyor without causing collision (interference) with adjacent portions of the machine while they are located on the central conveyor. In this mode of operation, not all of these innermost packages will be fully unwound at the time of the package transfer. Certain remnant windings will left on at least some of the packages removed by the central conveyor. It is also possible to provide drive to both the tube transfer carriage 20 and the package transport train 38. By means of the tube transfer carriage 20 supplied with electrical current, instructions can be transmitted to the drive of the package transport train 38. A sensor, for example infrared or light barrier should be provided on the tube transfer carriage 20 and should be directed towards the space provided for an empty tube on the removal conveyor 15. If an empty tube 11 is located at the relevant position on this conveyor, then no further tube may be transferred onto the relevant transverse path. The tube transfer carriage has two functions to fulfill, namely a) transfer of a fully wound package from the package transport train 38 onto the transverse support or transverse rail 16 and, b) transport of the packages 13', 18, 19 located on the transverse rail 16 including transfer of an empty tube from the transverse rail 16 onto the removal conveyor 15. It will be appreciated therefore that the tube transfer carriage could perform firstly the operation in accordance with previously quoted point b) without presence of a package transport train. In this way, an empty space is created at the outer end of the creel, that is of the relevant transverse rail 16. The tube transfer carriage can perform the movement in accordance with point a) above after carrying out the movement in accordance with point b). In the course of performing the operation according to point b), the tube transfer carriage 20 can store a signal indicating the necessity to perform a movement in accordance with point a). Further, it is conceivable to provide various kinds of robots on one ring spinning machine and in particular one robot which is designed only to perform a movement in accordance with point a) and further robot which is designed only for the movement in accordance with point b). Where two robots are provided (as mentioned above), one such robot can be integrated into the package conveying apparatus of the machine itself. This apparatus further comprises the creel rails (acting as guides and temporary supports), the central (receiving) conveyor and (possibly) a train re-loading mechanism (this is not necessary where the robot itself performs the re-loading operation). The other robot then acts as a mere interface between the transport means and the conveying apparatus of the machine. Such a robot could be adapted to serve a plurality of machines (with interlinked rail systems for the "interface" robot). A robot of this type would not necessarily have a rail system of its own, but could run on the main transport rails attaching itself (for example) to the "head" of a train when the latter reaches a specific machine. However the division of functions could also be arranged in the "reverse" sense, that is a special robot within the machine conveying apparatus could transfer packages to the removal conveyor, while another robot could both effect transfer into the creel and movement of packages within the creel. Timing of the changeover operation in relation to the "running time" of an individual package is very important. The central conveyor cannot accept packages of remnant windings above a certain diameter. The robot performing transfer onto the removal conveyor can therefore be provided with a sensor (for example as shown in Figure 7A) which prevents a transfer when the diameter of the inner package on the rail is above a predetermined limit (even if the transfer has been "signalled" by some separate means). Preferably, this sensor is also used to initiate a transfer from the innermost working position to the removal conveyor. Transfer to the removal conveyor 15 is not necessarily "linked" to transfer of a new reserve package into the creel. Due to the long running time of feed packages in a ring spinning machine (more than 30 hours), there will be plenty of time to replace a former reserve package which has been converted into a working package. The creel should, however, then be arranged to permit spinning of material fed from a working package located (temporarily) in the reserve position. A transfer into the creel necessitates the availability of a fresh reserve package, which is not under the sole control of the machine. Transfer within the creel, on the other hand, can be carried out under the control of the machine together with its associated robot. Where these transfers are not simultaneous, the need for a transfer into the creel could (for example) be signalled by a sensor responsive to the presence of absence of a package in the reserve position. It is not necessary to provide two separate robots in order to operate in this way. A single robot may be selectively operable in two modes, one mode enabling transfer of packages within the creel and the other mode enabling transfer of a package into the creel. The embodiment shown in Figure 7 is based on an arrangement in which the train is brought into alignment with a rail to be supplied with a fresh package. However, where the (or a) robot is separately movable and controllable, the presence of the train (transport means) at the time of a transfer into the creel is not necessary. The train could, for example, be delivered to a predetermined station relative to the machine, and the handling robot (or at least the "interface" robot) could be required to "fetch" a package from this station as and when necessary. This robot could even carry its own (small) store of packages to reduce the need for frequent return to the station. This station could of course also provide the station at which empty tubes (or remnant packages) are reloaded onto the train. The system could, for example, be arranged to operate so that a robot first "patrols" the creel and performs transfers within the creel, and then performs replacement runs (between the train at the predetermined station and the vacated reserve positions within the creel). Figure 8 shows schematically the rail 201 of network SN running past the ends of the ring spinning machines, together with one of those machines RS. This machine has associated therewith a circulation path 205 connected with a rail 201 by way of a spur-rail 203 and two points units 202,204. In order to reduce the size of the Figure, the curved rail sections at the end of the circulation path have been diagrammatically illustrated as straight line sections. A train can be brought onto the rails associated with the ring spinning machine RS via the spur-rail 203 and can be returned to the network via that spur-rail or, for example, by way of a second spur-rail SP1 indicated in dotted lines. The construction of a train for use in an installation according to Fig. 8 is illustrated diagrammatically in Figure 5 which also shows a very short length of the rail section 201. The train itself consists of elongated members 400 of rectangular section joined by joint elements 45. Each member 400 and each joint 45 carries a pin 404 on which a roving package or carrier for a roving package can be connected with the member or with the respective joint. The packages or package carriers hang freely downwardly from these pins 404. Each joint 45 is also connected with a U-shaped yoke 406 and each limb of the yoke has at its free end a freely rotatable wheel in the form of a roller 408. These wheels roll on suitable running surfaces of the rail 201 and transfer the weight of the train to the rail. A complete train can comprise any desired number of members 400 coupled together by joints 45 as described above. The joints simultaneously provide coupling units and vertical pivot axes so that the train can travel around curved sections of the rail network. Figure 9 also shows a suitable drive for use in the rail network. This drive comprises a plurality of friction roller assemblies one of which is illustrated at 410 in Figure 9. The assembly 410 consists of a motor 412 and a pair of friction rolls only one of which 416 can be seen in Figure 9. The friction rolls 416 are connected by respective shafts 414 with the motor 412. The wheels are so arranged that they engage respective opposed side surfaces of the members 400 and joints 402 when these elements lie directly underneath the motor 412. A friction wheel drive operating on this principle is shown in US patent specification No. 4769982. One assembly 410 is also schematically illustrated in Figure 8 which further shows an energy source Q1 for the motor 412 and a selectively operable switch S to enable supply of energy from the source Q1 to the assembly 410 and to interrupt that supply. The switch S is operable from the control unit AS (Figure 2) by way of a signal lead SL. Each individual assembly 410 can therefore be controlled by the control unit AS. Figure 10 shows the yoke 406 once again together with its roller pair 408 and a part of a joint 45. The yoke 406 (and the corresponding train) is not, however, this time moving along the rail 201 but on a rail 14 of the circulation path 205 (Fig. 8). On this circulation path, the train is not driven by friction roll assemblies 410, but by a chain conveyor 418 extending parallel to the path 205. The chain elements carry a strip 420 which is in frictional engagement with one of the rolls 408. When the chain conveyor 418 is set in motion along the path 205 and a train is standing on the rail 14, the movement of the chain conveyor, acting via the strips 420, causes rolling of the wheels 408 and therefore movement of the train. Two drive motors 422 are provided for conveyer 418 and are controlled by the control unit RSS of the relevant ring spinning machine (Fig. 8). The movement of the train along the circulation part 205 is therefore under the direct control of the spinning machine itself. The creel of the machine shown in Figure 8 has a plurality of transverse rails 16 extending at right angles to the longitudinal direction of the machine above the spinning positions. There is one such rail for each pair of adjacent spinning positions, although only three such rails per machine side have been illustrated in Figure 8 in order to avoid cluttering the drawing. The machine RS also comprises an endless conveyor belt 15 extending in the longitudinal direction of the machine and drivable by way of a motor 424. This motor is also controllable from the control unit RSS. Each transverse rail 16 (Figure 8) has two free ends one of which faces outwardly towards the circulation path 205 and the other of faces inwardly towards the conveyor belt 15. When the conveyor belt 15 is in a "start position", each transverse rail 16 is aligned with the holder bar 47 (Figure 7) of a respective take-up element associated therewith. The transfer of a roving package from a train running on the circulation path into the creel of the spinning machine could be controlled and monitored by the machine control unit RSS acting in response to sensors on a transfer carriage according to Figure 7 or acting in response to sensors built into the machine itself. This is not, however, strictly necessary. The transfer could be initiated, for example, by human operators by setting of "flag" at the end of a transverse rail 16 which has to be supplied with a new roving package. The unwinding of a roving package in order to deliver spinnable strand to a spinning position is carried out only relatively slowly and a complete unwinding operation lasts, for example, between 10 and 60 hours (or in some cases even longer) depending upon the yarn count to be spun. Accordingly, it is a relatively easy task for the operating personnel to patrol the machine periodically and to set the appropriate flags. However, in a fully automated ring spinning room, personnel cannot stand around continuously at the machines to monitor the complete procedure of loading roving packages into the creel. In accordance with this invention, the monitoring and overall control of creel loading is assumed by the control unit RSS of the individual machine (in spite of possible missing information concerning the individual transfer operations). The invention also ensures coordination of the operations at the individual machine with the control of the complete system by the appropriate control unit therefor. An embodiment suitable for fulfilling these tasks will now be explained with reference to Figures 14, 15 and 16. The explanation assumes a package carrier structure as illustrated in Figures 11, 12 and 13. The train 38 shown in Fig. 13 has a plurality of holders 124 secured thereto each of which carries a suspension element 125 releasably engaged therewith by a sliding connection. The elements 125 remain connected with the tubes 11 carried thereby throughout the movements described in this specification. In this case, the element 125 together with the associated tube 11 constitutes the "package carrier" 360. At the time of transfer of a carrier 360 into the creel, the respective tube 11 associated with that carrier bears windings of spinnable strand (for example roving) to make up a full package 13. By conversion from a reserve package to an operating package, the spinnable strand is gradually unwound from the relevant package and delivered into an associated spinning position as already described above. In the course of transfer of a full package 13 from the train 38 onto a creel path 16, a carrier 360 is released from a holder 124 of the train and a slider shoe defined by the limbs 126 of the element engages with the rail 16 in the creel. During transfer of empty tubes 11 from a rail 16 onto the holder bar 47 (Figs. 11 and 12), the belt 15 must be maintained stationary. After a predetermined number of empty tubes have been transferred to receiving elements 111 on the belt 15, the belt (which is guided on and tensioned around diverter rolls) can be driven along the machine with a predetermined speed. The rotational axes of the diverter rolls are preferably arranged in or near the central plane of the machine so that the belt 15 can serve both longitudinal sides of the machine. This operation of the belt 15 is preferably initiated when the number of empty tubes 11 carried by the belt equals the number of holders 124 on the train 38 to be loaded. In the course of this movement of the belt 15, a take-up element 111 passes a sensor, for example a light barrier, which causes a reduction of the speed of the belt. An initiator 148 (Fig. 12), responding to the metal studs 110, causes stopping of the belt 15 at a suitable position to enable activation of the pusher mechanism RV (Fig. 8) to transfer an empty tube 11 carried by the take-up element 111 onto the return rail 16'. When this has been completed, the belt 15 can be set in movement again until another tube 11 is brought into the appropriate position and the operation of the pusher mechanism can be repeated. After a complete rotation of the belt 15, all empty tubes 11 will have been transferred from the belt, whereupon a signal can be generated causing the train 38 with those tubes 11 to be returned into the transport network. This signal can also be transmitted to the central control AS (Fig. 2). The machine RS shown in Figure 8 is fitted for return of the empty tubes to the train with an additional rail 16' which is not associated with any of the spinning positions. Instead, it is provided with a return device indicated by the symbol RV in Figure 8. The device RV is under the control of the control system RSS of the relevant machine. The complete operation which has to be monitored and controlled by the machine control unit RSS will be divided for purposes of explanation into three sub-operations, namely Sub-operation 1: - arrival/departure of a train, Sub-operation 2: - loading of the creel up to the stage at which return of empty tubes to the train is initiated, Sub-operation 3: - return of empty tubes to the train. Sub-operation 1 - arrival/departure of a train The departure of a train from the buffer P (Figure 1) to a selected ring spinning machine RS is initiated by the installation control unit AS (Figure 2) and is carried out under the control of that central control unit AS up to the point at which the train passes the points unit 202 (Figure 8), for the relevant ring spinning machine. For this purpose, the network control AS sends signals to the switches S (Figure 8) of the appropriate assemblies 410 in order to effect movement of the train out of the buffer P and onto the spur-rail 203 (Figure 8). The departure of such a train is, however, effected only after the network control AS has received a "call" signal from the corresponding ring spinning machine RS. At the time of sending a call signal to the control AS, the control unit RSS of the individual machine will ensure that the points unit 204 (Figure 8) has being set to a condition enabling the train to pass from the spur-rail onto the circulation path 205 (Figure 8). At the time at which a call signal is sent, however, the motors 422 (Figure 8) of the chain conveyor 418 have not yet been set in motion, because there is no train on the circulation path 205 at that stage. At the time of despatch of a train from buffer P, the network control AS can set the points unit 202 to enable the train to move into the spur-rail 203. This spur-rail is made so short in relation to the length of the train that the leading end of the train passes over the points unit 204 and into the circulation path 205 before the trailing end of the train has left the last drive assembly 410 preceding the points unit 202. The arrival of the leading end of the train on the spur-rail 203 is registered by a sensor Sa (Figure 16) and is reported to the machine control RSS. This machine control then sets the chain conveyor 418 in operation so that when the leading end of the train has passed across the points unit 204 it will be engaged by the strip 420 (Figure 10). The train will then be drawn onto the circulation path 205 by the chain conveyor 418. The sensor Sa reports the passage of the trailing end of the train past that sensor to the machine control RSS which passes this report on to the central control AS. The points unit 201 can then be reset by the control AS so that the rail section 201 of the network SN is recompleted for movement of trains to other ring spinning machines connected to that section. A second sensor Sb is provided adjacent the points unit 204. The passage of the trailing end of the train past this sensor is also reported to the machine control unit RSS, whereupon the points unit 204 can be set by the machine control to close the circulation path 205. This report could of course also be used as the basis for the sending of a "train arrived" signal to the central control AS. Upon despatch of a train back into the network, the machine control RSS must first send a "ready signal" to the central control AS, which can then set the points unit 202 to the spur-rail 203 before a "despatch signal" is sent back to the machine control unit RSS. The machine control then sets the points unit 204 to the spur-rail 203 and switches the chain conveyor 418 into reverse so that the train is moved back over the spur-rail 203 until it comes into an engagement with at least one of the friction roller assemblies 410. The sensor Sa (Figure 14) reports the departure of the train from the spur-rail 203 to the machine control unit RSS which passes this report on to the central control AS. The points unit 202 can then be reset onto the network. The "sensor" Sa can for this purpose (if necessary) be formed as a group of individual sensor elements. When the train has passed the points unit 204 the chain conveyor 418 can be switched off. The despatch of the train via an additional spur-rail SP1 (Figure 8) will not be described here because the procedure is essentially the same for both variants. The system ensures an orderly transfer of the train at the control interface between the network control unit AS and the machine control unit RSS. However, this orderly transfer is in itself insufficient to ensure a controlled material flow in the complete installation. A train which has brought a predetermined number of roving packages to the ring spinning machine should carry the same number of empty tubes back into the network. If this prerequisite is not fulfilled in an individual case, then the central control unit AS must take measures to ensure that the "tube loss" is compensated within the network. Loss of "package units" could of course be detected by the network control AS within the network SN and could be compensated there. However, in order to ensure adequate control over the system at all times, each individual machine control unit (for example control RSS, Figure 8) is preferably provided with means to enable detection of the condition of a train temporarily associated with that ring spinning machine. The expression "condition of a train" refers in this connection to the presence or absence of roving packages or roving package carriers on the holders of the train. There are basically two methods for detecting the condition of a train. The number of loaded holders can be detected, or the number of empty holders can be detected. The former method is preferred for use in accordance with this invention. The determination of the condition of a train can also be carried out at various points of time. The condition could, for example, be detected immediately before despatch of the train and could be reported via the machine control unit RSS to the control unit AS. In accordance with a preferred arrangement according to this invention, however, the condition of the train is detected upon arrival of the train at the machine and the tube return operation (still to be described) is controlled in such manner that (as far as possible) the number of empty tube returned to the train is equal to the number of roving packages brought by the train upon its arrival at the machine. An arrangement of sensors suitable for performing a counting operation is diagrammatically illustrated in Figure 14. For this purpose, a second sensor Sc is associated with the previously described sensor Sb, the output signals of these two sensors being illustrated schematically in Figure 16. In the latter diagram, the horizontal axis represents time, while output voltage of the sensor is represented on the vertical axis. Upon detection of the leading end of a train, the output of sensor Sb goes, for example, high and the output remains in this condition until the trailing end of the train has passed this sensor (the sensor responds, for example, to the elements 400 shown in Figure 9). The sensor Sc responds in a similar manner to the individual packages carried by the train so that for each such package a signal pulse is generated by this sensor Sc. The output signals of the sensors Sb, Sc are delivered to a counter 430 (Figure 14) which can only count the pulses delivered from the sensor Sc while the signal voltage of the output of sensor Sb remains high. The number of counted pulses is then reported to the machine control unit RSS. Sensors Sb and Sc can, for example, be designed as light barriers with the sensor Sc responding, for example, to the upper end of the tube, which (on arrival of the train) carries windings of spinnable strand. Sub-operation 2: loading of the creel Is has already been mentioned that the individual transfer operations from the train into the creel are not necessarily initiated or monitored by the machine control unit RSS. They may be manually initiated, or they may be initiated by a semi-autonomous robot (carriage 20, Figure 7). The return of the empty tubes does however stand under the direct control of the machine control unit. This return operation can thus be carried out in a rational manner if the machine control unit RSS periodically receives information regarding the condition of the train. The required information depends upon the selected tube return procedure. It would be possible, for example, to return empty tubes to the train before all roving packages have been transferred into the creel. The machine control unit RSS must for this purpose be provided with information regarding the presence of vacant holders on the train. Preferably, however, the return of empty tubes to the train is only initiated when all roving packages have been transferred into the creel. In that case, the machine control unit RSS must at least be supplied with information as to the fact that the train has been emptied. Furthermore, even if the transfer of the individual roving packages from the train into the creel is not under the direct control of the machine control unit, the "loading rate" per unit time can at least be influenced by the machine control RSS because this unit determines the movements of the train along the circulation path 205. The machine control unit could (for example) as suggested in German specification No. 3601832) maintain the train continuously in movement along the circulation path 205. However, this requires a very high expenditure of energy without any assurance that the delivery of a roving package into the creel is necessary on any given circulation. It should also be mentioned that it is not necessary to replace the reserve package on a given transverse support (rail) as soon as that package has been converted into an operating package (feeding spinnable strand to a spinning position associated with this support). At that time, the packages in the operating positions on that support will still have a considerable running time until one of them becomes empty. Preferably, therefore, the train is not maintained in continuous movement along the circulation path 205, but the chain conveyor 418 is set periodically in operation in order to effect each time a complete circulation of the machine. The chain conveyor 418 is then stopped until the next circulation is initiated. When the chain conveyor 418 is stopped, the train preferably again stands in the parking position previously referred to. This is so arranged in relation to the machine that it does not prejudice access to the spinning positions. In the preferred arrangement, this parking position is located next to the additional rail 161 (Figure 8) so that the parking position also serves as a starting position for the return of tubes to the train. The machine is therefore preferably provided at least with means to detect the presence of the train in the parking position. In accordance with a further preferred feature of the invention, the number of occupied holders on the train is detected upon arrival of the train in the parking position and is exploited to control the intervals between two successive circulations. In this way, it is possible to avoid a situation in which the train "sits" for a long period in the parking position when the holders of the train are occupied only by a number of roving packages which is inadequate to fulfill the demand for such packages on the next succeeding circulation. Optimisation of the creel loading procedure of this kind can be carried out in various ways. The system should at least be arranged so that when the number of occupied holders on the train falls below the minimum number, the intervals between circulations are kept short in order to empty the train completely as rapidly as possible. The machine control RSS could, however, be so arranged that it performs a continual optimisation of the intervals between circulations in dependence upon the average demand for roving packages and the number of still occupied holders on the train. For this purpose, the number of roving packages delivered to the creel and/or the number of still-available roving packages on the train could be detected at each circulation. For this purpose, a sensor group comprising at least two sensor elements Sd and Se are provided at the parking position and are connected to a counter (not shown) in a manner similar to the sensors Sb and Sc described with reference to Figure 14. One of these sensors, for example sensor Sd, also operates to stop the train in the parking position in that a signal change at the output from this sensor in response to the trailing end of the train is used to switch off the chain conveyor 418 by way of the machine control unit RSS. Sub-operation 3: return of the empty tubes In order to control the return operation, the machine control unit RSS must be provided with information regarding the presence/absence of an empty tube at the return location of the conveyor belt 15. It must also have information regarding the presence/absence of an unoccupied holder 124 (Figure 13) at a receiving position on the circulation path 205. In order to derive this required information, the machine is provided with a further sensor Sf (Figure 15) located in a predetermined relation to the outer end of the additional rail 16' and reacting to the presence of a holder 124 within its sensing field. The necessary relationship of the sensor Sf to rail 16' depends upon the structure of the return device RV. Sensor Sf can comprise a light barrier. If necessary, this sensor can be formed by a group of sensing elements, one element of the group responding to the holder 124 and a second element of the group responding to the presence/ absence in this holder of a slider shoe defined by the limbs 126 (Figure 13). After occupation of a space (holder) in the train by a tube (slider shoe) transferred thereto by the return device RV, the train must be moved relative to the rail 16' in order to bring a further receiving position (holder) into the required relationship relative to the additional rail 16' to take up a further tube (slider shoe). The occupation of a space (holder) on the train can be reported to the machine control unit RSS by the return device RV and/or by the sensor Sf, whereupon the chain conveyor 418 can again be set in motion in order to move the train relative to the machine. The train must then be stopped again when a free space (holder) is located in the previously mentioned receiving position. However, this is preferably effected not by stopping the chain conveyor 418, but by means of a mechanical abutment AN (Figure 8). After the chain conveyor 418 has been set in motion, the abutment AN is placed in the path of motion of a holder 124 in order to stop the train when this holder comes into contact with the abutment AN (despite continued operation of the chain conveyor 418). The abutment AN itself is movable relative to the circulation path 205 between an operating position, where it can come into contact with a holder so as to hold the train, and a withdrawn position where it is unable to exert any influence upon the movement of the train. The extension/withdrawal of the abutment AN is effected automatically, for example by way of a mechanical linkage with the return device RV or via an individual motor controlled, for example, directly from the machine control unit RSS. The same effect could, of course, be achieved if the abutment AN is normally held in its operation position by a locking device which is released upon occupation of a previously free space (holder) on the train. The abutment AN is then automatically forced back from its extended position as soon as the train begins to move under the action of the continuously operated chain conveyor 418. As soon as the now occupied holder 124 has moved away from the receiving position, the abutment AN could be forced by mechanical bias back into its extended position and the locking device could be re-actuated to hold it there until the next holder has been re-loaded. When the train has been stopped, the sensor Sf reports whether the holder now located in the receiving position is or is not already occupied. If the holder is already occupied, for any reason beyond the control of the machine control unit itself, then the train must be set in motion again until a vacant holder has been located in the receiving position. The tube return operation should only be initiated by the machine control unit RSS when the train is ready to receive slider shoes with empty tubes thereon. Due to the previously mentioned relationship between the parking position and the tube return position, this ready state of the train is ensured when the train is standing in the parking position and is not carrying any roving packages; this condition can be detected by the sensors Sd and Se (Figure 15). For purposes of fully automatic operation, various criteria should be defined which will cause termination of the tube return procedure. This procedure must, of course, be broken off as soon as all holders 124 on the train have been occupied with slider shoes (whether or not the shoes are carrying empty tubes). This condition can be detected by the sensors Sd and Sf, and it causes initiation (via the machine control unit RSS) of the already described procedure for despatch of the train back into the transport network. This first criterium is not however alone sufficient because the control system cannot ensure either complete occupation of the holders on the train at the time of arrival of the train on the machine conveying system, or the continued presence of all slider shoes (empty tubes) delivered by the train into the creel. Preferably, therefore, the tube return operation is broken off when the number of slider shoes (with or without empty tubes) returned to the train equals the number of these elements carried by the train at the time of its arrival on the machine conveying system. The counting of the occupied spaces (holders) on the train by the sensors Sb and Sc (Figure 14) at the time of arrival of the train is therefore used by the machine control system RSS as a control criterium for the tube return procedure. The tube return procedure must also be broken off when there are no further slider shoes on the central conveyor belt 15. The machine control unit RSS can be so arranged that it determines the number of transfer operations carried out by the return device RV and compares this with the number of occupied spacers (holders) on the train at the time of its arrival. By this means, the loss of a tube (slider shoe) within the machine can be detected. In this case, at the time of despatch of a train back into the transport network, the machine control unit RSS can send an appropriate "tube missing" signal to the network control AS, thereby facilitating the further processing of this train within the rail network SN (Figure 1). However, a "required number" of occupied spaces (holders) on the train could be established (for example from case to case by the central control unit AS or by the installation designer, for example in the form of a predetermined "standard quantity"). The machine control unit RSS can then detect missing slider shoes or tubes by counting at the time of arrival of the train and can report this to the central control unit AS at the time of train arrival or at the time of despatch back into the installation network. A similar effect could be achieved in that at the time of arrival of the train, sensors are available to detect unoccupied spacers (holders) on the train and to report these to the machine control unit RSS, which in turn can report them to the central control AS. The positioning of a slider shoe 125 at the transfer location on the central conveyor belt 15 relative to the additional rail 16' also creates certain problems. It is known in advance that at the time of re-loading operation, not all of the holder bars 47 (Figure 12) on the central conveyor belt are occupied. Since in these exemplary embodiments it is assumed that the individual creel loading operations have not been carried out under the direct control of the control unit RSS, that unit does not have information regarding which holder bars 47 on the conveyor belt 15 are in fact occupied. For reasons of conservation of space within the machine, it will not normally not be desirable to bring the empty tubes carried by the central conveyor belt firstly to a collection location and then to transfer them sequentially to the transfer position for return to the train. Rather, the central conveyor belt 15 should itself be used as a temporary store for the empty tubes until they are to be returned to the train. The positioning of an empty tube (slider shoe) in the transfer position on the belt must therefore be carried out by controlled movements of the belt itself. Preferably, a "basic position" is defined for the conveyor belt in which each holder bar 47 (Figure 12) is aligned with a predetermined transverse rail 16, that is the holder bars 47 are not randomly associated with the transverse rails. This basic position can be indicated by a suitable "marking" on the conveyor beltsand can be detected by a corresponding sensor provided in the machine. This marking and the sensors will now be explained in somewhat further detail. Upon initiation of a tube return procedure, the conveyor belt 15 is set in motion out of this basic position by actuation of the motor 424 (Figure 8). The motion of the conveyor belt 15 is continued until a sensor determines that a slider shoe 125 stands in the transfer position. The motor 424 is then stopped until the return device RV or sensor Sf (Figure 17) has reported that a return operation has been carried out successfully. The movement of the conveyor belt 15 is then repeated until a further slider shoe has been located in the transfer position. The procedure itself has repeated until the return operation is broken off in accordance with the previously described criteria. The motor 424 is then again set in operation in order to bring the conveyor belt 15 back into its basic position. The system does not, however, ensure that upon termination of a tube return operation, all spaces on the conveyor belt 15 have been vacated. A sensor must therefore be provided to respond to the presence of a slider shoe or a tube on the conveyor belt 15 after termination of the return procedure. This sensor is preferably provided in the neighbourhood of the transfer position and serves at the same time as a further check that in the course of an individual return operation, each slider shoe (tube) previously positioned in the transfer position has in fact been moved off the holder bar 47 (Figure 12) at least onto the intermediate rail 16' (Figure 15). A preferred arrangement of sensors to fulfill all of these tasks will now be described with reference to Figure 15. It is assumed that in clearing of the central conveyor belt 15, this belt moves in counter clockwise direction considered with reference to Figure 8 and Figure 15. A first sensor Sg is then located slightly before the transfer position (considered in the direction of movement of the central conveyor belt 15) in order to respond to the presence of a slider shoe on the conveyor belt 15. The motor 424 is not immediately stopped, but its speed is reduced to a predetermined value (crawl operation). The crawling movement is continued until a sensor Sh detects that the relevant slider shoe 125 is aligned directly with the return rail 16'. This sensor Sh can, for example, be formed by a sensor responding to the securing means 110 (Figure 11) by which the element 47 is secured to the conveyor belt. The spacing between the sensors Sh and Sg must be so selected that (at the crawl speed of the conveyor belt), the holder bar 47 carrying the slider shoe 125 (Figure 13, 11) detected by the sensor Sg is located at the transfer position when the sensor Sh next responds to the presence of an object within its sensing field. A sensor Si responds to the presence of a slider shoe 125 on the conveyor belt 15 after completion of an individual return operation or after termination of a return procedure. The corresponding output signal from the sensor Si effects immediate stopping of the conveyor belt 15 and sets of an alarm in order to draw the attention of the machine operator to this defective condition. The defect must be attended to by the personnel. The basic position of belt 15 is detected by the sensor Sh acting in conjunction with sensor Sj. Sensor Sj responds (as in the case of the sensor Sh) to the securing means 110 (Figure 12) of a receiving element 111. In order to represent the basic condition of the conveyor belt 15, two additional "receiving elements" 111 are secured to the conveyor belt 15 with a spacing corresponding to the spacing between the sensors Sh and Sj. The spacing is preferably smaller than the spacing between two neighbouring transverse rails 16. The conveyor belt 15 is located in its basic position when this pair of "receiving elements" 111 stands in alignment with the respective sensors Sh and Sj. A further sensor Sk of the same type can be provided in order to detect (together with a sensor Sh) the approach of the conveyor belt to its basic position. The motor 424 (Figure 8) can then be switched to crawl operation in order to move the belt into the said basic position.

Claims: A spinning mill installation comprising at least one group of spinning machines (RS1,RS2,RS3,RS4 or generally RS) and a transport network (SN) for transporting packages (13) on package carriers (360) to the spinning machines (RS1,RS2,RS3,RS4) and for transporting package carriers (360) from the spinning machines (RS1,RS2,RS3, RS4), the packages (13) and package carriers (360) being transported on transport units (38), and further comprising a computer control (AS) for the transport network (SN) so that movements of the transport units (38) are determined by the control (AS) within the transport network (SN), characterised in that each individual machine (RS) of the group is provided with its own individual computer control unit (RSS1,RSS2, RSS3,RSS4 or generally RSS), and that for each spinning machine (RS) at least one respective control interface (SS; 202 or 204) is defined between the control (AS) for the transport network (SN) and the control unit (RSS) for the individual machine (RS), such that at an interface (SS; 202 or 204) control over movements of a transport unit (38) and/or packages (13) to be delivered to the respective machine (RS) by the transport unit (38) and/or package carriers (360) to be removed from the respective machine (RS) by the transport unit (38) is passed between the control (AS) for the network (SN) and the control unit (RSS) for the machine (RS). An installation as claimed in claim 1 characterised in that means (Sa,Sb,Sc;211,212) is provided to report the transfer of a transport unit (38) over the said interface (202 or 204) from the network control (AS) to the machine control unit (RSS) and vice versa. An installation as claimed in claim 1 or claim 2 characterised in that each transport unit (38) can carry a plurality of packages (13) and in that a transport unit (38) which, by passing over a control interface (202 or 204), has become subject to the control of a control unit (RSS) associated with a particular machine (RS) remains subject to that control until delivery of all packages (13) carried thereby and then carries empty package carriers (360) from the spinning machine (RS) back into the network (SN). An installation according to claim 3 characterised in that the spinning machine control unit (RSS) is adapted to control the delivery of packages (13) for processing in the spinning positions (21, 21') and also to control the return of empty package carriers (360) to the transport unit (38). An installation as claimed in one of claims 1 to 4 characterised in that for each spinning machine (RS1,RS2,RS3,RS4) means (212,213;Sb,Sc) is provided to perform a counting operation to determine the number of packages (13) delivered from the network (SN) on a particular transport unit (38). An installation according to claim 5 characterised in that as far as possible the machine control unit (RS) ensures the return of a corresponding number of empty package carriers (360) to the transport unit (38). An installation according to one of the preceding claims characterised in that each machine (RS1,RS2,RS3,RS4) is provided with conveying means (205,16,15,16') enabling movement of the packages (13) and/or package carriers (360) at the machine (RS), the control interface (202 or 204) being defined at a transport section (203) linking the network (SN) with the conveying means (205). An installation as claimed in claim 7 characterised in that a first drive means (410) is provided to move the transport unit (38) under the control of the network control (AS) and a second drive means (422,424) is provided to move the transport unit (38) under the control of the machine control unit (RSS). An installation as claimed in claim 7 characterised in that said conveying means comprises a semi-autonomous unit (20) operable to cause predetermined movements of packages (13) and/or package carriers (360) on the conveying means (205,16,15,16'). An installation according to claim 3 or claim 4 characterised in that a transport unit (38) subject to the control of a machine control unit (RSS) is thereby caused to circulate around the machine (RS) at intervals which are determined in dependence upon the demand for packages (13) in the machine creel (530,532,16) and the number of packages (13) remaining on the transport unit (38). An installation according to claim 10 characterised in that a parking position (213) is defined for the transport unit (38) between circulations and the parking position also represents the position (8) at which empty package carriers (360) can be returned to the transport unit (38). An installation as claimed in claim 11 characterised in that means (Sd,Se) are provided at the parking position (213) to detect periodically the number of packages (13) carried by the transport unit (38) and/or the number of unoccupied holders (125) in that unit (38). An installation as claimed in any one of claims 1 to 12 characterised in that each machine (RS) comprises a first path (16) extending transverse to the length of the machine (RS) and adapted to receive packages (13) from a transport unit (38), a second path (16') extending transverse to the length of the machine (RS) and adapted for return of package carriers (360) to the transport unit (38) and a third path (15) extending longitudinally of the machine (RS) and enabling movement of package carriers (360) between said first and second paths (16,16'). An installation in accordance with claim 13 characterised by a package handling robot (20) adapted to move packages (13) from the transport unit (38) to said first path (16). An installation in accordance with claim 14 characterised in that the robot (20) is adapted to move packages (13',18,19) and/or package carriers (360) already on said first path (16) along that path towards the third path (15). An installation according to claim 14 or claim 15 characterised in that the robot (20) is also adapted to move package carriers (360) on said second path (16') along that path away from the third path. An installation in accordance with claim 15 or claim 16 characterised in that the robot is adapted to move package carriers (360) from the first path (16) to the third path (15). An installation according to any one of claims 14 to 17 characterised in that the robot (20) is movable by a drive means (39,56) controllable by the control unit (RSS) of the machine (RS). An installation as claimed in any one of claims 13 to 18 characterised in that the third path (15) is formed by a conveyor belt drivable under the control of the control unit (RSS) of the machine (RS).

Inventors: ERNI MARKUS, FLUETSCH CHRISTIAN, FRITSCHI ISIDOR, HEFTI WALTER, ERNI, MARKUS, FLUETSCH, CHRISTIAN, FRITSCHI, ISIDOR, HEFTI, WALTER, Flütsch, Christian
Applicants: RIETER AG MASCHF, MASCHINENFABRIK RIETER AG
Application year: 1990
Main classification: D01H9
IPC codes: D01H9