Method and apparatus for controlling a thread storage and feeder device

Claim 3

A method according to claim 1 including the steps of controlling rotation of said motor at a maximum and a minimum number of revolutions, if the amount of thread supply on the thread drum is at a minimum limit and a maximum limit, respectively, by means of said control signal and controlling rotation of said motor by said signal related to average thread consumption when said thread supply on said drum is between said limits.

Claim 4

A method according to claim 1 including the step of deriving the signal representative of average thread consumption from the time interval during which the thread supply on said drum corresponds to at least one predetermined value.

Claim 5

A method according to claim 3 wherein said predetermined value corresponds to one of said minimum or maximum thread supply limits.

Claim 6

A method according to claim 1 wherein said signal related to the amount of thread supply is fed to an integrator prior to being combined with the other of said electric signals.

Claim 7

A method according to claim 5 wherein said electric signal representative of average thread consumption takes the form of a train of pulses of triangular shape and including the steps of adding said pulses to the output signal of said integrator to provide a summing signal, applying the latter signal to a threshold circuit, and utilizing the output signal of said threshold circuit for activating a drive circuit for said motor.

Claim 8

Apparatus for controlling the rotational speed of a winding member of a thread storage and feeding device for thread processing machines which includes a thread drum for momentarily storing thread from a supply bobbin in the form of a thread supply, comprising an electric motor for driving said winding member, sensing means responsive to the amount of said thread supply momentarily present on said thread drum and a signal processing means connected between the sensing means and the electric motor, which in a lower range a, an upper range b and a middle range c, provides for different output signals controlling the rotational speed of the motor, characterized in that the signal processing means (14, 16, 18, C18, 20) includes a signal correction means (16) which stores the value of the output signal used in range c before this range has been left for range a or range b and that the signal processing means corrects the value stored in the correction means when the yarn supply is either in range a or range b.

Claim 9

Apparatus for controlling the rotational speed of a winding member of a thread storage and feeding device for thread processing machines which includes a thread drum for momentarily storing thread from a supply bobbin in the form of a thread supply, comprising an electric motor for driving said winding member, sensing means responsive to the amount of said thread supply momentarily present on said thread drum and a signal processing means connected between the sensing means and the electric motor, which in a lower range a, an upper range b and a middle range c, provides for different output signals controlling the rotational speed of the motor, characterized in that the signal processing means (14, 16, 18, C18, 20) includes a signal correction means (16) which stores the value of the output signal used in range c before this range has been left for range a or range b and that the signal processing means corrects the value stored in the correction means when the yarn supply is either in range a or range b.

Claim 10

Apparatus according to claim 7 characterized in that the value of the signal for controlling the speed of the electric motor in a range c is varied in accordance with the time periods during which the amount of thread supply stays in range a or range b, respectively.

Claim 11

Apparatus according to claim 7, characterized in that the signal correction means includes a pulse former (14) which clips the time periods in which the yarn supply is in range b.

Claim 12

Apparatus according to claim 7, characterized in that the signal correction means is an integrator (16).

Claim 13

Apparatus according to claim 7, characterized in that the signal processing means (14, 16, 18 C18, 20) includes a saw-tooth generator (20) whose saw-tooth signal is added in a summing member (18) to the signal from said integrator, in that the sum signal is subtracted in a comparator (C18) from the output signal of said sensing means.

Claim 14

Apparatus according to claim 11, characterized in that the frequency of the saw-tooth signal is between 5 Hz and 25 Hz.

Claim 15

Apparatus according to claim 7, characterized in that the sensing means (6, 7, 8, 11) includes a sensor (8) for range a and a further sensor (7) for range b.