Abstract: A weft picking control method capable of realizing control of a weft picking arriving time with a quick response over a wide range. The weft picking control method in an air-jet loom includes supplying air under pressure to weft picking nozzles, and jetting air under pressure from the weft picking nozzles so as to pick a weft into a warp shed together with the jetted air. Also, a supply passage for supplying the pressurized air to the weft picking nozzles includes high and low pressure supply passages. The passages are arranged in parallel with each other, and the air under pressure is jetted from the weft picking nozzles in cooperation with the two supply passages.

Abstract: A device for noise attenuation attenuates the noises generated from weaving machines and comprises first conversion means for receiving a sound and outputting an electrical acoustic signal corresponding to the sound, first signal processing means for receiving the acousto-electric signal and outputting a first electrical signal having the frequency and amplitude corresponding to a sound to be attenuated on the basis of the received acoustic-electric signal, second signal processing means for receiving the first electrical signal and outputting a second electrical signal having the same frequency and inverted phase relative to the first electrical signal, and second conversion means for receiving the second electrical signal and generating a sound corresponding to the received second electrical signal.

Abstract: A warp yarn breakage detecting and indicating apparatus capable of stopping the loom upon the detection of the breakage of a warp yarn and indicating the position of the broken warp yarn. The warp yarn breakage detecting and indicating apparatus comprises a stop control circuit for stopping the loom upon the detection of the breakage of a warp yarn, and an indication control circuit for indicating the position of the broken warp yarn, which are connected alternately to the dropper unit of the loom. Thus, the two control circuits are able to operate individually to implement the respective control functions thereof without adversely affecting each other for warp yarn breakage detection and for warp yarn breakage indication.

Abstract: A warp tension control method by which the let-off motion of a loom is controlled to regulate the tension of the warp yarns. A force of the same dimension as the controlled variable, namely, the tension of the warp yarns, is applied to a mechanism supporting the tension roller of the let-off motion for displacement under the control of an electric control system to control the warp tension at a high accuracy.

Abstract: A weft insertion control method for controlling the operation of a weft inserting device which measures and reserves a weft by winding the weft on a stationary measuring and reserving drum by means of a rotary yarn guide, releases the weft from and detains the same on the measuring and reserving drum by reciprocating a detaining pin to the measuring and reserving drum, and picks the weft wound and reserved on the measuring and reserving drum by a picking nozzle, including a detaining pin driving process in which a present weft releasing angle and a reference weft detaining angle are compared with the phase angle the loom, the detaining pin is retracted at the weft releasing angle to separate the detaining pin from the circumference of the measuring and reserving drum and the detaining pin is advanced at the reference weft detaining angle to bring the detaining pin into abutment with the circumference of the measuring and reserving drum; a detecting process in which the number of winds of the weft unwound from

Abstract: A voltage to be applied to the primary winding of a drive motor is automatically and time-functionally adjusted in relation to the rated voltage of the drive motor in order to provide sufficiently large torque for beating during the starting period of the loom running and transit to normal running of the loom is carried out at a preselected moment other than the moment of beating motion. Change in voltage is effected through either switching in mode of connection for the primary winding or transforming the power source voltage which is maintained constant.

Abstract: A weft inserting apparatus in a jet loom comprises a nozzle for inserting a stored weft yarn through a shed on a jet of fluid, weft insertion control means such as a control valve for controlling the starting and ending of the insertion of the weft yarn through the shed, and a control unit for determining a delay time based on a rotating condition of the jet loom at least under a transient operating condition of the jet loom, and for controlling the weft insertion control means to allow the weft yarn to be inserted for a prescribed period upon elapse of the delay time after an angle for starting apparent weft insertion.

Abstract: Production of a weft defect on a cloth under weaving is detected by at least two weft detection units arranged side-by-side on a loom along the path of travel of inserted wefts for issuing a defect signal which is then subjected to automatic allocation of a corresponding penalty. Penalty-loaded defect signals are sequentially accumulated at a control counter so that the loom is stopped when a count at the control has exceeded a given threshold. When a defect is removed by manual mending on the loom during a dwell, a corresponding gain is automatically subtracted from the count at the control counter during sequential accumulation in order to subdue the count below the threshold and to allow restarting of the loom. Automatic inspection on the loom can be carried out on a level with conventional manual inspection of the loom.

Abstract: A drive motor for each loom is selectively connected to a given commercial frequency power source for high speed rotation at normal running of the loom and to a low frequency power unit for low speed rotation at inching operation, thereby assuring accurate inching operation with cheap cost on looms under mass drive condition.

Abstract: The amplitude of a signal (original waveform) produced by weft sensors is relativized, and the signal waveform is analyzed in various aspects based on multiple parameters to discriminate a weft yarn and a jet of fluid accurately. More specifically, a discriminating function is calculated beforehand from a signal indicative of the weft yarn and jet of fluid under normal weft insertion conditions, and a signal produced in actual detection operation is compared with the discriminating function to determine whether the weft yarn is present or not. The discriminating function can be obtained by extracting feature parameters from a signal generated by the weft sensors, and relativizing the feature parameters with respect to the original signal waveform to find a reference quantity. The feature parameters include the original waveform per se, a differentiated value thereof, an integrated value thereof, frequencies in certain frequency ranges, and sampling averages of the above parameters.