A cable, preferably with a detachable connector, extends from the control system of the yam feeding device through and out of the housing of the yam feeding device to the control unit of the yam oiler and is transmitting a signal by galvanic conduction, which signal represents the rotational speed in the yarn feeding device. This necessitates to structurally prepare the yam feeding device accordingly for the co-action with the yam oiler and excludes to use per se the yam oiler with other yarn feeding devices having no such corresponding preparation. The prerequisites are similar for the other such accessory devices like controlled yam brakes, slip conveyors or rotational drives for storage bobbins from which the yam feeding device is pulling off the yam, because all said accessory devices also need said rotation speed signal for the co-action with the yam feeding device. In case that the yam feeding device is used without accessory device, the costly preparation of its control system and its housing is superfluous. In addition, the provided galvanic connection for the speed signal transmission might undesirably influence the control of the yam feeding device in case of a disturbance at the side of the accessory device or along the signal transmission path.

It is a task of the invention to provide a yarn processing system of the kind as disclosed above as well as an electronic sensor which are able to avoid a preparation of the yarn feeding device in terms of its control system and/or its design in view to a co-action with any kind of such speed depending controlled driven accessory device, which furthermore allow to easiiy use any speed depending driven accessory device at different types of yarn feeding devices, and wherein the danger of a disturbing influence of the accessory device to the control system of the yam feeding device is avoided.

Said task can be achieved with the features of claim 1 and the features of independent claim 15.

Since the sensor is galvanically separated and independent from the yarn feeding device, it can be used practically for any type of yam feeding device, even if the yam feeding device as used has no constructional preparation or adaptation of its control system for a transmission of a speed signal to the exterior. By this the production costs of the yam feeding device can be reduced. Any type of accessory device of the kind as mentioned above can be combined later with already used yarn feeding devices.

Surprisingly simple at least an outwardly leaking part of a rotating magnetic feed can be detected from the exterior on a yarn feeding device which has an interior component which is rotatably driven by an electric motor and in a controlled fashion. Said leaking part of the rotating magnetic field is available at the mounting location of the sensor but is not used at this location for the function of the yarn feeding device. It is only necessary to select the mounting location of the sensor such that the sensor is able to reliably detect the rotation of the magnetic field. On the basis of said leaking part of the magnetic field the sensor generates a signal representing the rotational speed of the component within the yam feeding device. Normally, the housings of yam feeding devices do not shield sufficiently strong in order to suppress at least the leakage of a part of the magnetic field which leaking part suffices to be detected and to generate the speed signal. Sensors detecting the leakage or wasted part of the magnetic field allow to expand the range of applications for yam feeding devices and for accessory devices being driven in dependence from the rotational speed of the yarn feeding devices, since thanks to the sensor such accessory devices can even be applied on yarn feeding devices which per se are not prepared for a speed depending co-action with any accessory devices.

According to claim 2, the signal is transmitted to the accessory device from the signal exit port of the sensor, preferably to the control unit of the accessory device. By which extent said signal then is used in the accessory device depends on the control routine of _ the accessory device. In any case it is assured that the speed signal is available when necessary without interfering with the control system or the drive means of the yam feeding device by a prefabricated and/or disturbance-sensitive galvanic connection.

Provided that the sensor is equipped with a signal cable and a detachable connector the sensor can be combined with any type of accessory device needing said speed signal.

Even such accessory devices may be used with the sensor which already are prepared for a galvanic connection with the control system or the drive means of the yam feeding device.

According to claim 3, the sensor thanks to its own power supply is independent from the yam feeding device, and optionally, also from the accessory device.

According to claim 4, the sensor is supplied with operational power either from the accessory device or independently of the accessory device from a power supply box of the yam feeding device. Such box is usually equipped with spare connection ports or connection ports thereon can be provided with minimum effort. Furthermore, the sensor may be connected to a completely independent power supply or may be provided with a battery inside such that the sensor remains completely independent from any other power source.

According to claim 5, the sensor is used at least to assist in the control of a yarn impregnation device, e. g., a yam oiler, which is provided along the yarn path in order to apply an impregnation substance as oil or wax on the yam. This impregnation is important for certain yam qualities in view to a proper processing of the yarn.

According to claim 6, the accessory device is a slip conveyor having at least one friction roll driven in dependence from the rotational speed in the yarn feeding device or from the yarn speed. Said slip conveyor either assists in withdrawing the yam at a withdrawal side from the yarn feeding device or in conveying the yam at the inlet side towards the yam feeding device.

According to claim 7, the accessory device is a controlled yam brake, the braking effect of which is variable in dependence from the yam speed. Said controlled yarn brake may be provided at the inlet side and/or withdrawal side of the yarn feeding device.

According to claim 8, the accessory device using the speed signal of the sensor is a rotational drive of a storage bobbin carrying the yam for the yam feeding device. The purpose of said rotational drive is to reduce or eliminate the twist or drill of the yarn normally resulting when pulling off yam from a stationary storage bobbin. This can be important for high fabric quality when weaving Lurex or band yarns.

According to claim 9, the sensor is mounted at its mounting location by the carrier means of the yam impregnation device, preferably at or close to the inlet side housing end wall of the yam feeding device. At this location, particularly in the area of the inlet eyeiet of the yarn feeding device, e. g. the rotation of the magnetic field of the drive motor easily is detectable by the sensor. The sensor may be integrated per se into the carrier means.

Alternatively, the sensor may be designed with own fixing means, or the carrier means may be provided with a fixing means enabling simple positioning of the sensor.

According to claim 10, the speed signal generated in the sensor is transmitted to the control unit of the electric motor of the treatment element of the yam impregnation device. If the signal exit port of the sensor is permanently connected with the control unit, the sensor so to speak is an integrated part of a structural unit consisting of the yam impregnation device, the carrier means and the sensor. In case that the signal exit port is releasably connected to the control unit, the sensor selectively also may be used with other types of accessory devices. It then is even possible to connect the yam impregnation device in conventional galvanic manner without the sensor to the control system of a yam feeding device accordingly prepared for the galvanic co-action with the yam impregnation device. One type of an accessory device selectively may be combined with different yarn feeding devices.

According to claim 11, a receiving socket for the sensor is formed at the housing of the yam feeding device, e. g., an insertion opening, a threaded bore or a hang-in hole. Said receiving socket can readily be formed with tools available at the working location of the yam processing systems, e. g. in a weaving mill. It is also possible to already form a receiving socket like an insertion opening, a bayonet socket, a screw-in socket or the like in the yam feeding device housing during manufacturing of the yam feeding device, however, without using any galvanic connection to the control system or the drive means of the yam feeding device.

According to claim 12, said accessory device is located separately and remotely from said yarn feeding device, while the sensor is located at or close to the yam feeding device. Signal transmission takes place via a cable. This allows to position the accessory device arbitrarily at a location where it optimally fulfils its purpose.

According to claim 13, the part of the magnetic fieid used for the speed detection is a leaking out part of a driving, controlling or monitoring magnetic field of the drive motor, i. e., of an electric motor of the yam feeding device. The rotation of the magnetic field is representing the momentary rotational speed of all components in the yarn feeding device driven by said electric motor, or the rotational speed of the motor itself, or even the momentary yarn speed, respectively.

According to claim 14, the sensor for deriving the speed signal detects the rotation of a part of a magnetic field which part is not used for the function of the yam feeding device at the mounting location of the sensor. Said magnetic field originates from a permanent magnet belonging to a rotation detector which is integrated into the yam feeding device.

Conventionally, the winding element is defined by an outwardly protruding winding tube and/or a winding disk on the drive shaft and is made of non-magnetic material. The rotation detector integrated into the yam feeding device (e. g. US-A-4,715,411) consists of the permanent magnet provided at the winding element, and of a stationary positioned detecting element like a Hall element. The rotational movement of the magnetic field generated by the permanent magnet during operation of the yarn feeding device is detectable by the sensor even when it is galvanically separated from the control system and the drive means of the yam feeding device. For said purpose the sensor ought to be situated close to said winding element at the stationary housing of the yam feeding device.

According to claim 16, the sensor is provided with a probe-shaped housing for the pick- up head apt to detect rotating magnetic fields and/or magnetic field variations of rotating magnetic fields without galvanic connection. The housing of the sensor is to be positioned where at least a part of a magnetic field is leaking outwardly to the pick-up head, said part being not used for the function of the yam feeding device at the mounting location of the sensor. It is possible to provide a fixation means at the sensor. In order to gain a forceful and clear speed signal and to achieve a compfetely independent operation of the sensor, an amplification and evaluation circuitry might be useful received in the sensor housing.

According to claim 17, the sensor easily may be glued to the housing at the mounting location.

According to claim 18, the sensor can be mounted with a fixing band at the housing of the yam feeding device.

According to claim 19, at least one of the existing protrusions or cooling fins of the housing of the yam feeding device is used to mount the sensor at its mounting location by means of a clamp engaging at said protrusion or cooling fin, respectively.

The speed signal generated by the sensor without a galvanic connection with the control system or the drive means of the yam feeding device is used in the accessory device to control the movement of a device part in dependence from the rotational speed in the yam feeding device. It is possible to control said device part permanently or only in predetermined operational phases according to said rotational speed. It may then be controlled with direct or indirect portion to the rotational speed. In a yam impregnation device with a rotating treatment element the speed signal is used to vary the rotational speed of the treatment element. In a controlled yam brake said speed signal is used to varying the braking or tensioning effect on the yam by means of at least one moveable braking element. In a drive for a storage bobbin said speed signal is used to rotate said bobbin according to the rotational speed in the yarn feeding device such that the yarn leaving the bobbin receives only a reduced drill or no drill or twist at all. In a slip conveyor a slip element is driven accordingly to adjust the slip in yam conveying direction corresponding to the momentary yarn speed.

Embodiments of the invention will be explained with the help of the drawings. In the drawings is: Fig. 1 a schematic side view of a yam processing system, and Fig. 2 an enlarged side view of a sensor detecting the rotational speed in a yarn feeding device or the linear speed of the yarn entering the yam feeding device.

A yarn processing system T in Fig. 1 comprises as a main component a yarn feeding device F, namely and as shown, a weft yarn storing and feeding device for a weaving machine. Instead of a weft yam storing and feeding device, said yam processing system T could include a yam storing and feeding device for a knitting machine, e. g. with a rotating storage drum (not shown). In the path of a yarn Y processed by the yarn feeding device F for downstream consumption at least one accessory device Z, Z1, Z2, Z3 is provided co-acting with the yam feeding device F such that the accessory device is mechanically acting upon the yarn Y in dependence from the linear yarn speed or the rotational speed of at least one component rotating inside the yarn feeding device F.

The accessory device Z may, e. g. be a yam impregnation device 9, i. e. a so-called yam oiler, applying a substance (oil or wax) onto the yam Y in order to facilitate its further processing in the yam feeding device and/or in the textile machine (weaving or knitting machine) consuming said yam. Accessory device Z in Fig. 1 is mounted to a housing 1 of the yam feeding device F. It is, however, possible to instead position the respective accessory device, i. e. even the yam impregnation device Z, elsewhere along the yam path and separated or remote from the yam feeding device F as shown in dotted lines for e. g. accessory device Z2, between the yam feeding device F and a yam storage bobbin 15. Alternatively or additively, to the yam impregnation device 9 said accessory device Z2 could be a controlled yam brake or a controlled yarn tensioner located between the storage bobbin 15 and the yarn feeding device. Accessory device Z mounted to housing 1 instead of said yam impregnation device 9 may be a controlled yam input brake. Dotted shown accessory device Z3 could be a controlled yarn brake at the exit or output side of the yam feeding device. Also one accessory device (e. g. Z, Z2 or Z3) could be a controlled slip conveyor withdrawing the yam at the output side of the yam feeding device F or conveying the yam to the inlet side with slip by means of at least one driven friction roll. Accessory device Z1 shown in dotted lines at storage bobbin 15 may be a rotation drive for the storage bobbin 15 to drive the later with a variable rotational speed such that during withdrawal of the yam Y from the storage bobbin 15 no or just reduced twist occurs. In brief, in the yam processing system T of Fig. 1 only one accessory device or several accessory devices may be used.

A characterising feature of the respective accessory device as used is a controlled moveable device part the movement control of which at least temporarily has to consider the rotational speed in the yam feeding device F or the linear speed of the yarn Y, respectively. For this reason a speed signal generated by an exterior located electronic sensor S is transmitted for control purposes to the accessory device. In the yarn processing system T, a common sensor S could be used for all respective accessory devices, or a number of sensors S corresponding to the number of accessory devices may be provided.

Yam feeding device F is receiving in housing 1 an electric motor M driving a drive shaft 2 of a winding element 4. Yam feeding device F has a storage drum 3 for storing the yam Y in windings from which windings the consuming textile machine (a weaving or a knitting machine) is withdrawing the yam axially or tangentially. The electric motor M of the yarn feeding device F is connected to a control system C to which signals of a schematically indicated yam sensor device 6 may be input for control purposes. Housing 1 may include a rotation detector integrated into the yam feeding device F in signal transmitting connection with control system C, as indicated. Said rotation detector consists of a permanent magnet 8 secured to the winding element 4, and of a stationary detecting element 7 associated to and aligned with the passage path of said permanent magnet 8.

Winding element 4 is a disk made of non-magnetic material and rotates with drive shaft 2. Permanent magnet 8 is fixed to said winding disk at an appropriate location. Yam feeding device F is supplied with operation and control power via a cable 5 connected to a power supply box B, to which further yam processing systems of the textile machine can be connected as well (not shown).

The yarn impregnation device 9, e. g. constituting said accessory device Z, comprises at least one treatment element 10 (e. g. an application roll) rotatably driven by an electric motor M1. Treatment element 10 receives an impregnating substance, e. g. from a not shown wick, and transfer said substance onto yam Y while the latter is guided through the yarn impregnation device 9. An electronic control unit C1 is provided in said yam impregnation device 9 for electronic motor M1. Operation and control powers for the yarn impregnation device 9 are supplied via a cable 11 either from an own power source or as shown from power supply box B.

The accessory device C or the yam impregnation device 9, respectively, is fixed by a carrier means 12, e. g. by at least one holding bracket to housing 1, either at the lower side of housing 1 or at an iniet side end wall of housing 1. In said inlet side end wall of housing 1 conventionally fixation bores for accessory devices of different kinds are pre- formed. Sensor S is integrated into carrier means 12 such that it contacts the housing end wall or is located adjacent to it, particularly at a mounting location X at which during rotation of at least a component K of the yam feeding device F (e. g. of electric motor M) at least a through leaking part of a rotating magnetic field is effective. Sensor S is incorporated into carrier means 12 either by an own fixation part 13 or by a fixation means G. Said rotating magnetic field may be the driving, the controlling or the supervising magnetic field of the electric motor M, respectively.

The sensor S is an electronic sensor deriving a signal from the rotation of the magnetic field or the detected part of said magnetic field without having galvanic connection to the control system C or the electric drive motor M of the yarn feeding device F. Said signal is representing the rotational speed in the yam feeding device F and indirectly the linear yarn speed as well, since the yam Y is wound onto storage drum 3 by the rotation of winding element 4.

In the embodiment shown, the sensor S is connected via a signal transmitting and, optionally, a power supply cable 14 to a connection port 20 of accessory device Z.

Connection port 20 can comprise a plug such that the connection is releasable.

Alternatively, sensor S can be connected to an own power supply, e. g. to the power supply box B or even to a completely separated power source. As an example a dash- dotted line indicates a connection between sensor S and power supply box B. Instead, sensor S could be equipped with an own permanent power source, e. g. a battery, in order to operate the sensor S completely independently. Since here accessory device Z already is supplied with power via a cable 11, it is suitable to supply sensor S also directly with operational power from accessory device C, e. g. via cable 14. The respective accessory device Z, Z1, Z2 and Z3 receives the speed signal on signal cable 14.

In Fig. 1 in dotted lines also another mounting location X1 for such a sensor S is shown.

Said location X1 is situated close to winding element 4 such that sensor S positioned at X1 at housing 1 is detecting the rotation of the magnetic field to generate the necessary speed signal without the galvanic connection to the control system C or to drive motor M of the yam feeding device F. Said leaking part at location X1 of the magnetic field otherwise is not used for the operation of the yam feeding device F.

Sensor S may-as explained-be positioned with its fixation means G at the selected mounting location X or X1. Altematively, it is possible for this purpose to form a receiving socket for sensor S in housing 1 of the yam feeding device F, e. g. an insertion bore socket, a threaded bore or a hang-in opening. It is even possible to beforehand manufacture the housing 1 of the yarn feeding device F with an insertion socket, a threaded socket, a bayonet socket or a hang-in opening for sensor S or for the fixation means G of sensor S.

The electronic sensor S in Fig. 2 has a probe-shaped housing 16 receiving a pick-up head A, e. g. in the region of a housing end portion 17. Optionally, at housing end portion 17 an elastic layer 18 may be provided avoiding a direct hard contact between housing 16 and housing 1 (Fig. 1). The fixation means G of sensor S in Fig. 2 here is collar-like and is secured to housing 16, preferably in an axially displaceable fashion, and comprises a fixation part 19 which might be equipped with different fixation points or fixation means in order to position the sensor S at the intended mounting location X or X1 or at other not shown mounting location. An amplifying circuitry D and a evaluation circuitry E can be integrated into housing 16. The speed signal is output at signal exit port H of sensor S to be transmitted via cable 14.

As a fixation G for sensor S a plastic, rubber or foam material body on housing 16 could be used having a permanent adhesive coating such that sensor S simply can be glued to housing 1. Altematively, sensor S could be secured by means of a tensioning band extending around housing 1 or around a part of housing 1 of the yam feeding device F.

As a further alternative a spring loaded clamp could constitute said fixation means G.

Said clamp could be secured to an existing protrusion or a cooling fin of housing 1. In case that no accessory device Z is mounted directly to housing 1 carrier means 12 or a similar carrier means could be used to solely position sensor S at the intended mounting location X or X1.