Weft feeler unit for a fluid-jet loom

Claim 2

Improved weft feeler unit for a fluid-jet loom comprising a weft feeler made up of first and second electrodes which are mounted to the reed of said loom on the weft arrival side whilst being spaced from each other along the travelling path of a weft, and means for applying high electric voltage to said electrodes which is high enough to establish a virtual electric connection between said electrodes and said weft by means of electric discharge as long as said weft has been normally inserted even when said weft actually does not come into contact with said electrodes due to whipping.

Claim 3

Improved weft feeler unit for a fluid-jet loom comprising a weft feeler made up of first and second electrodes which are mounted to the reed of said loom on the weft arrival side whilst being spaced from each other along the travelling path of a weft, an electric power source connected to said first electrode and supplying high electric voltage to said electrodes which is high enough to establish a virtual electric connection between said electrodes and said weft by means of electric discharge as long as said weft has been normally inserted even when said weft actually does not come into contact with said electrodes due to whipping, and a detection circuit connected to said second electrode and issuing an operation signal for the drive control unit of said loom insertion in accordance with the condition of said weft insertion.

Claim 4

Improved weft feeler unit for a fluid-jet loom comprising a weft feeler made up of first and second electrodes which are mounted to the reed of said loom on the weft arrival side whilst being spaced from each other along the travelling path of a weft, an electric power source connected to said first electrode and supplying high electric voltage to said electrodes which is high enough to establish a virtual electric connection between said electrodes and said weft by means of electric discharge as long as said weft has been normally inserted even when said weft actually does not come into contact with said electrodes due to whipping, and a detection circuit connected to said second electrode and issuing an operation signal for the drive control unit of said loom insertion in accordance with the condition of said weft insertion.

Claim 5

Improved weft feeler unit as claimed in claim 2 further including a normally open switch (S 1) arranged between said first electrode (2a) and said electric power source (1), said switch (S 1 ) being closed only when said weft comes to the position of said weft feeler.

Claim 6

Improved weft feeler unit as claimed in claim 2 or 3 in which said detection circuit includes a weft insertion signal generator connected to said second electrode (2b) and selectively generating one of electric normal, false normal and abnormal weft insertion signals at every weft insertion depending on the condition of said weft insertion, a normally closed switch (S 2 ) arranged between said weft insertion signal generator and the earth, which is made open only when said weft arrives at the position of said weft feeler, a reference signal generator for generating a threshold electric signal at every weft insertion whose level is between those of said normal and false normal electric weft insertion signals, and a comparator circuit connected to said weft insertion signal and reference signal generators.

Claim 7

Improved weft feeler unit as claimed in claim 4 in which said detection circuit further includes a timing signal generator (7) for generating an electric timing signal at every weft insertion at a timing between said weft insertion and cloth-fell beating, and an AND-gate (8) connected to said comparator circuit (6) and said timing signal generator (7), and generating said operation signal when enabled.

Claim 8

Improved weft feeler unit as claimed in claim 4 in which said weft insertion signal generator includes an amplifier (3) connected to said second electrode (2b), and an integration circuit (4) connected to said amplifier (3).

Claim 9

Improved weft feeler unit as claimed in claim 1 or 2 in which the value of said high electric voltage to be applied to said electrodes is in a range from 900 to 3,000 V.