Method for controlling shot-wise the yarn-feed when weaving pile fabrics on a Jacquard loom

Abstract

 There is described a method which comprises performing the following steps: feeding the length of a pile yarn as reference value to a processor - comparing the recorded conveyed yarn length with said reference value - during said comparison, providing an information as a function of a signal which shows whether a yarn should form or not pile - generating an alarm signal by "no weaving-in of pile yarn" or when conveying a yarn length lying outside the pre-determined tolerances.

Description

[0001] This invention relates to a method for controlling shot-wise the yarn-feed when weaving pile fabrics on a Jacquard loom.

[0002] When controlling the accurate feeding of the pile-forming yarns, various mechanical systems are presently used, which are based on measuring the yarn tension. When too high a tension is noticed, a small contact arm is then gene­rally raised, while with a yarn break a small control arm falls down, which may be noticed in both cases due to the alarm signal derived therefrom.

[0003] Due to the dust-full surroundings and the high variations in the generated tensions, the systems being used up to now are effective but in a limited way.

[0004] The invention has for object to obviate said drawbacks and to design a device which provides with original and technically-reliable means, a solution which makes it possible to stop the loom whenever any one of the following conditions is sensed:

1. Insufficient yarn feed or no yarn feed;

2. Too high a tension, which would lead to the yarn breaking.

[0005] To obtain the above according to the invention, the method according to the invention is based on the following steps:

1. Both conveying lengths per shot (weaving-in, respectively pile weaving) from a pile yarn to be woven are determined and said yarn lengths are fed as minimum and maximum values, or nominal values, together with tolerances, by way of reference values to a processor;

2. When weaving a shot, the recorded conveyed yarn length is compared to the one said reference values;

3. With the comparison as defined in 2, the processor provides an information as a function of a signal which originates in the Jacquard mechanism and wherefrom there appears whether a yarn should or should not form pile;

4. An alarm signal is generated should a yarn length be conveyed which falls outside said determined referen­ce values.

[0006] The invention further pertains to a device for controlling the yarn-feed when weaving pile fabrics of the above-­defined kind.

[0007] The invention particularly pertains to an origi­nal device which makes it possible to provide a reliable infor­mation regarding the yarn-feed, whereby there may be deduced from such an information whether the yarn-feed lies below or above the programmed value. This may mean that the yarn is broken or the yarn-feed is so limited that this must necessa­rily lead to breaking.

[0008] To make this possible according to the invention, the device comprises first of all, an apparatus which reads with a photocell the Jacquard patterns and records the informa­tion thereof (weaving-in, respectively pile weaving), as well as an apparatus wherewith feeding a yarn length to be woven is measured, which apparatus comprises a running wheel where­over the yarn to be woven is lead, and a disk rotating in synchronism with said running wheel, which acts together with a photocell as a pulse counter, and means to couple the informa­tion provided by said pulse counter, by means of a clock for every yarn to be controlled, to an electronic memory.

[0009] Other details and advantages of the invention will stand out from the following description, given by way of non limitative example and with reference to the accompanying drawings, in which:

Figure 1 is a diagrammatic showing of that appa­ratus from the device, which is responsible for measuring the yarn length being conveyed.

Figure 2 is a diagram of the device according to the invention.

Figure 3 is a diagrammatic showing of that appa­ratus from the device according to the invention, which is responsible for recording the Jacquard data (weaving-in, respec­tively pile weaving).

[0010] The device according to the invention is based on synchroneously reading two data which are to be controlled and read shot-wise.

[0011] First of all, the command to form or not pile from a yarn is recorded. This occurs by means of the apparatus 1 (figure 3). Said apparatus comprises a light source 2 and a set photo-electric cells (one for each pile yarn) which are mounted in the part 3. For each shot, a Jacquard card 4 is lead through apparatus 1. Thereby, through the pertaining photo-­electric cell, the information (weaving-in, respectively pile weaving) is recorded. In the usual way, a drive drum 5 insures the shot wise displacement of the cards present in a magazine 6. The Jacquard mechanism is shown with reference 7.

[0012] Secondly, the length of the yarn being conveyed should also be measured with an apparatus which has been originally designed thereof.

[0013] The apparatus as shown in figure 1 which measures the conveyed yarn length, comprises notably the following compo­nents: a bobbin 8 the yarn 9 is unwound from, a conventional tension generator 10, two yarn guides 11, a pulley 12 which is fast to a shaft whereon a disk 13 is also secured. Said disk 13 is provided with a series slits 14 which let the light beams originating from a light source, through to a photocell 15. The pulley 12 is thus rotated due to the engagement thereof with yarn 9, over an angle which is a direct function of the conveyed yarn length. The light pulses the disk 13 lets through per time unit are counted by means of said photocell 15.

[0014] When too many pulses are being counted, this means that the tension in yarn 9 is too low.

[0015] Conversely, when too few pulses are being counted per time unit, this means that the tension is becoming too high. Such tension will increase with each shot and lead to the yarn breaking.

[0016] Too high or too low a tension (no tension means break) is deduced from the recorded pulse number. Said number is compared with reference values which may correspond with a minimum/maximum value or with a nominal value with tolerance.

[0017] Together with the recorded information pertaining to the conveyed yarn length, there is also collected from the conventional Jacqard cards, the required information which determines whether a yarn should form or not pile.

[0018] The synchroneous processing of both informations is made clear with reference to figure 2.

[0019] In the diagrammatic showing from figure 2, the photocell for reading the Jacquard cards is shown with reference numeral 15. A photocell is connected for each yarn and the information which causes the command "weaving-in" or "pile weaving" for a yarn is conveyed through a switch 17 controlled by a clock 16, to a memory 18 where the information is stored. From memory 18, the information is coupled through a step switch 19 to a processor 20.

[0020] Similarly, the pulses counted with disk 13 are coupled to a counter 22 driven by a clock 21. One counter is provided for each yarn. From the counters 22, the information reaches memories 23. Said memories 23 contain information regar­ding the ascertained yarn length, which information reaches processor 20 through a step switch 24. Said step switches 19 and 24 have to operate synchroneously in such a way that infor­mation from one specific memory 18 and from one specific memory 23 always pertain to one and the same pile yarn. Processor 20 further comprises a connection member 25 which insures connection to a comparator 26 or 26ʹ. Both comparators 26 and 26ʹ compare the input information with the information from the pre-set units 27 and 28, which contain the reference values (weaving-in, respectively pile weaving). Said connection member 25 is so driven by the information contained in said memories 18, that with pile-weaving or respectively weaving-in, the data from said memories 23 are fed to comparator 26ʹ or respecti­vely 26.

[0021] The processor technology should be such that a comparison can be made stepwise (that is yarn by yarn) with the programmed value (yarn length) and this as a function of the Jacquard data. When under such conditions, a pile-wea­ving-in yarn lies outside the determined reference values, an alarm signal will be generated in 29.

[0022] It must be understood that the invention is in no way limited to the above embodiments and that many changes may be brought therein without departing from the scope of the invention as defined by the appended claims.

[0023] For instance, it is clear that the method and the device used thereby may also be applied when instead of in-woven yarns, floating yarns are present.

Claims

1. Method for controlling shot-wise the yarn-­feed when weaving pile fabrics by means of a Jacquard loom, which comprises the following steps:

1. The length of a pile yarn to be woven is determined and this yarn length is fed as minimum and maximum value, or as nominal value together with a tolerance, by way of reference value to a processor;

2. when weaving-in a shot, the recorded conveyed yarn length is compared with said reference value;

3. with the comparison performed as defined in 2., an information is provided by the processor as a function of a signal which originates from the Jacquard mechanism and which shows whether a yarn should form or not pile;

4. an alarm signal is generated by "no weaving-in of pile yarn" or when conveying a yarn length lying outside the defined to­lerances.

2. Device for controlling shot-wise the yarn-feed when weaving pile fabrics by means of a Jacquard loom, which comprises an apparatus which reads by means of a photocell, the Jacquard cards and records the information thereof (weaving-­in, respectively pile weaving).

3. Device as defined in claim 2, which further comprises an apparatus wherewith the feeding of a yarn length to be woven-in is controlled, which apparatus comprises a pulley or running wheel (12) whereover the yarn (9) is lead, and a disk (13) rotating synchroneously with said pulley (12), which acts together with a photocell (15) as pulse counter, and means to couple the information provided by said pulse counter, through a clock for each yarn to be controlled, to an electronic memory.

4. Device as defined in either one of claims 2 and 3, which further comprises for each yarn, a memory (18) which stores the information provided beforehand by the Jacquard mechanism and couples such information to a processor (20).

5. Device as defined in any one of claims 2 to 4, which further comprises for each yarn, a memory (23) which stores the information provided beforehand by the appara­tus wherewith the yarn-feed is controlled, and couples such information to a processor (20).

6. Device as defined in either one of claims 4 and 5, in which said processor (20) comprises a connection member (25) which insures connecting to comparator (26), respec­tively (26ʹ).

7. Device as defined in claim 6, in which said comparators (26), respectively (26ʹ) are so designed as to make possible a comparison with pre-set units (27) and (28), which contain the reference values (weaving-in, respectively pile weaving).

8. Device as defined in any one of claims 4 to 7, in which the technology of said processor (20) is such that a comparison can be made stepwise (that is yarn per yarn) with the programmed value (yarn length) and this as a function of the Jacquard data (weaving-in, respectively pile weaving).

9. Device as defined in claim 8, in which an alarm signal is generated when during said comparison, a diver­ging value relative to the programmed value is ascertained.

Drawing