Textiles: weaving – Stopping – Weft
Reexamination Certificate
2002-05-10
2004-12-28
Worrell, Danny (Department: 3765)
Textiles: weaving
Stopping
Weft
Reexamination Certificate
active
06834683
ABSTRACT:
This application is based on and claims the priority under 35 U.S.C. §119 of German Patent Application 101 15 172.1, filed on Jun. 8, 2001, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
The invention relates generally to air jet weaving looms and particularly to the monitoring of the weft insertion in an air jet weaving loom, particularly downstream of the exit of the weft insertion channel.
BACKGROUND INFORMATION
German Patent Publication DE 44 43 371 C1 corresponding to U.S. Pat. No. 5,606,998 (Wahhoud et al.) discloses a weft thread stretching mechanism and a weft thread detection or monitoring device for jet weaving looms. The main purpose of the disclosure of U.S. Pat. No. 5,606,998 is to avoid identifying a temporary excess length of the leading end section of a weft thread that occurs due to stretching of the weft thread, as a weft thread break. More specifically, the temporary excessive weft thread length at the leading end section of the weft thread shall not lead to stopping the weaving loom. The excess length is temporarily caused by exposing the leading end of the weft to a stretching operation by a stretching jet that is effective to blow the leading end of the weft thread in a direction perpendicularly to the feed advance direction defined by the longitudinal axis of the weft insertion channel. The stretching jet blows the leading end of the weft through a stretching channel extending in a plane laterally displaced from the plane defined by the feed advance direction. For this purpose, the monitors or so-called weft stop motion devices are arranged at the end of the stretching channel or path. Additionally, the axial length of the stretching channel is adjustable. In order to accommodate this adjustable length of the stretching channel, the position of the weft stop motion devices at the end of the stretching channel is also adjustable in the axial direction of the main weft insertion channel of the loom. Such a structure avoids identifying a temporary excess length that occurs due to the stretching of the weft thread as a weft break. As a result, the loom operation is not erroneously shut down. Only when the leading end of the weft does not pass all the way through the stretching channel will the loom stopping signal be generated.
German Patent Publication DE 195 45 839 C1, corresponding to U.S. Pat. No. 5,735,316 (Hehle) relates to a method and apparatus in an air jet weaving loom for avoiding the formation of a so-called catch selvage. Instead, a leading end of the inserted weft thread is stretched by a special deflecting weft stretching jet nozzle and the deflected end is cut off and withdrawn by suction. A first weft stop motion device is positioned at the exit of the weft insertion channel upstream of the stretching nozzle. A second weft stop motion device is positioned downstream of the stretching channel.
German Patent Publication DE 198 02 254 C1 corresponding to U.S. Pat. No. 6,082,413 (Scorl et al.) relates to a weft thread stretching and detecting mechanism for air jet weaving looms in which again the leading end of the weft thread is deflected by a stretching nozzle into a separate stretching channel that extends in a plane different from the plane defined by the longitudinal axis of the weft thread insertion channel. A first weft stop motion device is arranged upstream of the catch selvage and upstream of the deflecting stretching nozzle. A single second weft stop motion device is arranged at the exit end of the stretching channel and at the end of the extension of the weft insertion channel. A beam transmitter and a beam sensor are so arranged relative to each other at the exit ends of the stretching channel and of the insertion channel so that the beam must cross the exits of both channels. This position of the weft stop motion device can monitor both the insertion channel and the stretching channel in order to ascertain whether an excessively long weft thread or a broken weft thread is involved.
European Patent Publications EP 0,493,847 A1 (Bamelis) and EP 0,645,485 A1 (Granelli et al.) disclose different types of stretching channels. In both instances the weft stop motion device is arranged upstream of the stretching channel at the exit of the insertion channel.
In all known devices with a stretching channel that is either aligned with the insertion channel or is positioned in a different plane from the plane of the insertion channel, it is not excluded that a leading end section of the weft thread is deformed, for example by the formation of a loop or kink. The positioning of the weft stop motion devices according to the prior art does not enable these devices to ascertain whether a leading end section of a weft thread has been deformed. If a weft thread with a loop or a kink in its leading end section is beat-up into the fabric, the resulting fabric does not meet the required quality.
OBJECTS OF THE INVENTION
In view of the foregoing it is the aim of the invention to achieve the following objects singly or in combination:
avoid weaving a weft thread deformation, particularly a loop or a kink at the leading end section of a weft thread into the fabric;
to position either an additional weft stop motion device or the so-called first weft stop motion device in a location where the weft thread deformation, particularly at the leading end of the weft thread can be positively discovered for producing a control signal that will cause a corrective action in the loom operation; and
to generate a loom stop signal in response to the absence of the leading end of the weft thread in the stretching channel and to evaluate the presence of the leading end of the weft threads in the stretching channel as a weft thread that has not been deformed.
SUMMARY OF THE INVENTION
The above objects have been achieved according to the invention in a method for detecting a deformation such as a loop or a kink in a leading end section of a weft thread exiting from a weft insertion channel in an air jet weaving loom by performing the following steps:
(a) positioning an additional weft stop motion device (
10
) in an entrance area of a weft stretching path,
(b) exposing said leading end section of said weft thread to a stretching force in said weft stretching path downstream of said weft insertion channel,
(c) monitoring with said additional weft stop motion device (
10
) a presence or absence of a leading end (
7
B) of said leading end section (
7
A) of said weft thread (
7
) in said entrance area of said weft stretching path downstream of said waft insertion channel, and
(d) generating a loom control signal in response to said presence or absence of said leading end (
7
B) in said entrance area of said weft stretching path.
Positioning the weft stop motion device in an entrance area of the weft stretching path allows monitoring the arrival and any deformation of the leading end section of a weft thread.
The method according to the invention is performed by an apparatus that comprises a weft stretching channel positioned downstream of the weft insertion channel. The weft stretching channel has an entrance area where a jet nozzle is positioned for seizing the leading end section of the weft thread and driving the weft thread into the entrance area of the weft stretching channel and then through the weft stretching channel. According to the invention, a weft stop motion device is positioned in the weft stretching channel or rather in a position for monitoring the passage of the leading weft thread end through the stretching channel to thereby ascertain the presence or absence of the leading end section of the weft thread in the weft stretching channel.
The weft stretching channel may be positioned in axial alignment with the longitudinal axis of the weft insertion channel or it may be positioned in a plane other than a plane defined by the longitudinal axis of the weft insertion channel. In both instances the weft stop motion device will be positioned to monitor the presence or absence of the leading end section of the weft thread i
Birner Werner
Chvorak Alexander
Dornier Peter D.
Hannes Christian
Reinhardt Herbert
Fasse W. F.
Fasse W. G.
Lindauer Dornier Gesellschaft mbH
Worrell Danny
LandOfFree
Method and apparatus for monitoring a leading end of a weft... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for monitoring a leading end of a weft..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for monitoring a leading end of a weft... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3281212