EP0107110A1 — Yarn storing, feeding and measuring device

Claim 1

Independent Claim 320 words

Yarn storing, feeding and measuring device (1), particularly for jet looms, having a stationary storage drum (2) onto which an intermediate yarn store is wound by a winding-on device (3) and from which the yarn (F) is withdrawn spiralling around the withdrawal end of the storage drum (2), yarn sensing means (6) being arranged such that the yarn is passing its detection area during withdrawal from the drum (2), said yarn sensing means (6) producing pulse signals, each pulse signal indicating that the yarn (F) passes a detection area of the yarn sensing means (6), a plurality of yarn stopping devices (10) being arranged at angular intervals around the storage drum (2), said yarn stopping devices (10) consisting of yarn stopping elements (14) and of actuator means (11) moving said stopping elements (14) into and out of the path of the yarn being withdrawn, and an actuator control device (8) adjustable to desired yarn lengths to be withdrawn, said control device (8) being responsive to said pulse signals in such a way that an actuating signal is transmitted to a selected yarn stopping device (10) whose angular position corresponds to the position rendered by the yarn when said desired yarn length has been withdrawn, characterized in that said yarn sensing means (6) consists of yarn sensors (6), the number thereof being lower than and independent from the number of yarn stopping devices (10), and that said control device (8) comprises storing means (20) for storing an information regarding the yarn stopping device (10) actuated at the end of a previous yarn withdrawal cycle and calculating means (20) for determining one yarn stopping device (10) to be actuated next among the plurality of yarn stopping devices (10) on the basis of an input information for the calculating means (20) representing said desired yarn length and on the basis of said stored information in the order to obtain the desired yarn length.

Claim 2

Dependent Claim 320 words

Yarn storing, feeding and measuring device (1), particularly for jet looms, having a stationary storage drum (2) onto which an intermediate yarn store is wound by a winding-on device (3) and from which the yarn (F) is withdrawn spiralling around the withdrawal end of the storage drum (2), yarn sensing means (6) being arranged such that the yarn is passing its detection area during withdrawal from the drum (2), said yarn sensing means (6) producing pulse signals, each pulse signal indicating that the yarn (F) passes a detection area of the yarn sensing means (6), a plurality of yarn stopping devices (10) being arranged at angular intervals around the storage drum (2), said yarn stopping devices (10) consisting of yarn stopping elements (14) and of actuator means (11) moving said stopping elements (14) into and out of the path of the yarn being withdrawn, and an actuator control device (8) adjustable to desired yarn lengths to be withdrawn, said control device (8) being responsive to said pulse signals in such a way that an actuating signal is transmitted to a selected yarn stopping device (10) whose angular position corresponds to the position rendered by the yarn when said desired yarn length has been withdrawn, characterized in that said yarn sensing means (6) consists of yarn sensors (6), the number thereof being lower than and independent from the number of yarn stopping devices (10), and that said control device (8) comprises storing means (20) for storing an information regarding the yarn stopping device (10) actuated at the end of a previous yarn withdrawal cycle and calculating means (20) for determining one yarn stopping device (10) to be actuated next among the plurality of yarn stopping devices (10) on the basis of an input information for the calculating means (20) representing said desired yarn length and on the basis of said stored information in the order to obtain the desired yarn length.

Claim 3

Dependent Claim 22 words

Device as claimed in claim 1, characterized in that the yarn sensing means (6 ) consists of a single yarn sensor (6).

Claim 4

Dependent Claim 44 words

Device as claimed in claim 2, characterized in that the stored information regarding the yarn stopping device (10) actuated at the end of the previous withdrawal cycle indicates the relative angular position of said stopping device (10) with respect to said yarn sensor (6).

Claim 5

Dependent Claim 148 words

Device as claimed in one of claims 1-3, characterized in that the calculating means (20) determines on the basis of the desired yarn length an actuation position of the withdrawal point of the yarn (F) being withdrawn from the storage drum (2) at which the determined stopping device (10) is to be actuated, that the calculating means (20) measures the period of time between the occurrence of two subsequent pulse signals, generated by the yarn sensor (6), that the calculating means calculates the i momentary position of the withdrawal point of the yarn (F) i being withdrawn from the storage drum (2) with respect to the respective position of each yarn stopping device (10) on the basis of said measured period of time, and that the calculating means (20) actuates the determined stopping device (10) as soon as the calculated momentary position equals to said determined actuation position.

Claim 6

Dependent Claim 173 words

Device as claimed in claim 4, characterized in that the calculating means (20) carries out the following steps for determining the momentary position of the withdrawal point of the yarn (F): a) Setting the calculated momentary position to a value corresponding to the position of the previously actuated stopping device (10), b) Incrementing the calculated momentary position with a pre-determined rate and checking whether the calculated momentary position equals to the position of a yarn sensor (6) or whether the calculated momentary position equals to the actuation position, c) In case the calculated momentary position equals to the position of the yarn sensor, holding the calculated momentary position and checking whether the yarn sensor generates a pulse signal; going back to step d) as soon as the yarn sensor generates said pulse signal, said generation of said pulse signal indicating that the calculated momentary position equals to the real position of the withdrawal point of the yarn, d) In case the momentary position equals to the actuation position, actuating said determined stopping device.

Claim 7

Dependent Claim 113 words

Device as claimed in claims 4 or 5, characterized in that the actuation position of the withdrawal point of the yarn (F) being withdrawn from the storage drum (2) is determined such that the period of time lapsing during the movement of the withdrawal point of the yarn (F) from said actuation position to the position of the stopping element (14) of the determined stopping device (10) is greater than the response time of said stopping device (10), said response time being defined by the time delay between feeding an actuation current to the actuator means (11) of the stopping device (10) and the completing of the movement of the stopping element (14).

Claim 8

Dependent Claim 157 words

Device as claimed in one of claims 1-3, characterized in that the calculating means (20) determines on the basis of the desired yarn length an actuation time defining the period of time between releasing the stopping device (10) actuated at the end of the previous withdrawal cycle and actuating the determined stopping device (10) to be actuated next, that the calculating means (20) calculates the period of time lapsed since the releasing or deactuation of said stopping device (10) actuated at the end of the previous withdrawal cycle, that the calculating means (20) corrects this calculation of the period of time on the basis of the respective period of time between two subsequent pulse signals received from the yarn sensor (6), and that the calculating means (20) generates an actuation signal for actuating the actuator means (11) of the determined stopping device (10) as soon as the calculated period of time corresponds to the determined actuation time.

Claim 9

Dependent Claim 54 words

Device as claimed in claim 7, characterized in that the calculated period of time lapsed since the releasing or the deactuation of said stopping device (10) actuated at the end of the previous withdrawal cycle represents an angular position of the withdrawal point of the yarn (F) being withdrawn from the storage drum (2).

Claim 10

Dependent Claim 209 words

Device as claimed in claims 7 or 8, characterized in that the calculating means (20) carries out the following steps for calculating the period of time lapsed since the releasing or deactuation of said stopping device (10) actuated at the end of the previous withdrawal cycle: a) Resetting a value to zero when releasing or deactuating the stopping dev ice (10), said value representing said calculated period of time, b) Incrementing said value with a pre-determined rate and checking, bi) Whether said value equals to the actuation time or bii) whether said value equals to a pre-set time being chosen such that it is a few percent, preferably 10%, smaller than the period of time lapsing during the withdrawal of one turn of yarn (F) from the storage drum (2) or whether it equals to said pre-set time multiplied by n, n being a whole number greater than zero, c) In case condition bi) is fulfilled generating the actuation signal, d) In case condition bii) is fulfilled holding said value being equal to the pre-set time or to a whole multiple thereof, e) Then checking whether the yarn sensor (6) generates the next pulse signal, and f) Going back to step b) as soon as condition e) is fulfilled.

Claim 11

Dependent Claim 97 words

Device for a jet loom having a jet nozzle for inserting the weft yarn during the process of weaving by means of compressed air, wherein the jet of compressed air generated by the jet nozzle can be controlled by means of an electromagnetic valve operable by a driving current for controlling the feeding of compressed air to said nozzle, as claimed in one of claims 4-9, characterized in that the calculating means (20) is electrically connected to said valve for controlling the opening and closing thereof in time-dependency from the actuation of the respective stopping devices (10).

Claim 12

Dependent Claim 61 words

Device as claimed in claim 10, characterized in that the calculating means (20) is arranged to open said valve a pre-determined period of time before deactivating the stopping device (10) actuated at the end of a previous yarn withdrawal cycle and to close said valve a pre-determined period of time before activating the determined stopping device (10) to be actuated next.

Claim 13

Dependent Claim 59 words

Device as claimed in, claim 11, characterized in that said pre-determined period of time corresponds to the response time of said valve and said jet nozzle, said response time being defined by the time delay between feeding the driving current to said electromagnetic valve and the point of time at which the jet of compressed air has completely established.

Claim 14

Dependent Claim 19 words

Device as claimed in one of claims 1-12, characterized in that the calculating means (20) is a microprocessor (20).

Claim 15

Dependent Claim 122 words

Device as claimed in one of claims 1-13, characterized in that each yarn stopping element (14) consists of a metal ball (14) being movably disposed in a radial bore (15) provided in a guiding portion (16) located close to the withdrawal end of the storage drum (2), that each actuator means (11) comprises an electromagnetic coil (11) being arranged in spaced relationship to said guiding portion (16) so as to define a gap (18) between the guding portion (16) and the coil (11), and that the metal ball (14) is attracted by the coil when supplying the coil (11) with the actuation current so that the metal ball (14) moves into the gap (18) for stopping the withdrawal of the yarn (F).

Claim 16

Dependent Claim 42 words

Device as claimed in claim 14, characterized in that there is provided a permanent magnet (17) located at one end of said bore (15) for moving back said metal ball (14) into said bore (15) when the actuation current is switched off.

Yarn storing, feeding and measuring device

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