Textiles: weaving – Warp manipulation – Shedding
Reexamination Certificate
2000-06-19
2001-09-25
Falik, Andy (Department: 3765)
Textiles: weaving
Warp manipulation
Shedding
C139S059000, C139S455000
Reexamination Certificate
active
06293315
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process and a device for positioning warp yarns and to a weaving loom equipped with such a device.
2. Brief Discussion of the Related Art
In the domain of weaving looms of the Jacquard type, it is known to proceed with the levelling of the harness, i.e. with the adjustment, with respect to the frame of the weaving loom, of the position of the mails of the heddles in their direction of displacement in their substantially vertical reciprocating movement. The aim is to obtain a high-precision positioning of the warp yarns during weaving. In the known devices, such adjustment generally takes place in two steps:
when the harness is manufactured, the harness cords are adjusted manually and individually to the and required length;
when the Jacquard mechanism is positioned on its bearing structure, the positioning of this mechanism is adjusted by acting manually on jacks, in order to adjust the height of the mails of the heddles.
Such manual adjustments are long, fastidious, expensive and always imprecise, and their quality can be influenced if the operator is tired or lacks concentration.
It is a particular object of the present invention to overcome these drawbacks by proposing a device for positioning the warp yarns, which may be used automatically, with a precision and a reproducibility greatly improved over the known techniques.
SUMMARY OF THE INVENTION
To that end, the invention relates to a device for positioning warp yarns of a weaving loom, controlled for forming the shed by electrical actuators, which comprises a first detector, common to the yarns driven by different actuators, for detecting the passage of at least one warp yarn into a determined position and a second means for determining the value of a control parameter of the corresponding actuator upon passage of a yarn into this position.
Thanks to the invention, it is possible to displace a warp yarn or a group of warp yarns by activating an actuator to a predetermined position, which may be checked by to the first detector, while the second means makes it possible to acquire a value of a control parameter of the actuator which may then be used a control point for controlling the actuator.
According to a first advantageous embodiment of the invention, the first detector is a detection assembly fixed on a frame of the loom and comprising a source of emission of an undulatory signal and a cell disposed opposite this source with respect to the warp yarns and adapted to detect a variation of the undulatory signal. In particular, this source may be an emitter of a laser beam, while the cell is adapted to detect a variation in intensity of this beam which occurs when one of the warp yarns interferes with the laser beam.
According to a second embodiment of the invention, the first detector comprises a filiform sensor disposed in a direction parallel to the warp yarns of the loom.
According to a third embodiment, the first detector comprises a carriage movable along a support extending in a direction substantially parallel to the weft yarns of the loom. The carriage is equipped with a contact sensor adapted to selectively cooperate with one of the warp yarns. In that case, the carriage may be secured to an extension adapted to come into contact with certain warp yarns of the loom, the contacts between the warp yarns and the extension making it possible to generate a force of displacement of the carriage on the support.
Whatever the variant envisaged for the first detector, it can be employed automatically, i.e. in reproducible and reliable manner.
The invention also relates to a weaving loom comprising a device as described hereinabove. Such a loom operates more reliably and more precisely than known looms, while its installation and maintenance are largely simplified.
The invention also relates to a process for positioning the warp yarns of a weaving loom which may be carried out with the device described hereinabove and, more specifically, to a process which consists in:
displacing at least one warp yarn by an of the actuator which is associated therewith;
detecting the passage of the warp yarn into a predetermined position;
selecting a value of a control parameter of the actuator upon passage of the yarn into the predetermined position; and
using the selected value a control point for controlling the actuator.
This process has the advantage of being automated and of enabling the stroke of the heddles of a weaving loom to be adjusted by programming the electrical actuator associated with each heddle or group of heddles without manual intervention on the harness cords. In other words, the possible misalignments between the heddles and harness cords may be compensated by controlling the electrical actuator from the value selected as a control point which corresponds to the same position for the different warp yarns.
According to an advantageous aspect of the invention, the process consists in using the selected value of the parameter for determining at least one control point of the parameter corresponding to at least one particular position of the movement of the yarn generated by the actuator. Thanks to this aspect of the invention, the selected value allows the warp yarns to be positioned with precision along their entire path.
According to another advantageous aspect, the process is applicable when a plurality of warp yarns are displaced by to a single actuator, which is the case in a weaving loom equipped with a dobby or in a weaving loom of the Jacquard type with plural repeated patterns in the width of the fabric. In that case, the passage of at least one of the warp yarns driven by the actuator into the determined position is detected and the selected value of the parameter is used for controlling the actuator. For example, in a group of a plurality of yarns, the first yarn reaching the predetermined position and the last yarn reaching this position may be detected, the two values of the control parameter of the actuator being selected and used by a monitoring unit for controlling the actuator. The first value is able to be used for determining the bottom dead center of the corresponding stroke and the second value is used for determining the top dead center.
REFERENCES:
patent: 3817292 (1974-06-01), Doehler et al.
patent: 5070913 (1991-12-01), Palmer
patent: 5613526 (1997-03-01), Palau et al.
patent: 5803133 (1998-09-01), Slosse et al.
patent: 0353005 (1990-01-01), None
patent: 0774538 (1997-05-01), None
patent: 0879908 (1998-11-01), None
patent: 408081850 (1996-03-01), None
patent: 9268450 (1997-10-01), None
patent: 9733024 (1997-09-01), None
Braun Dominique
Froment Jean-Paul
Dowell & Dowell , P.C.
Falik Andy
Staubli Faverges
LandOfFree
Process and device for positioning weaving loom warp yarns does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process and device for positioning weaving loom warp yarns, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process and device for positioning weaving loom warp yarns will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2437317