GB2032472A - Creation of Inventions and Patents with Artificial Intelligence

GB2032472A – Controlling Fabric Tension in Weaving Looms
– Google Patents

GB2032472A – Controlling Fabric Tension in Weaving Looms
– Google Patents
Controlling Fabric Tension in Weaving Looms

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Publication number
GB2032472A

GB2032472A
GB7925304A
GB7925304A
GB2032472A
GB 2032472 A
GB2032472 A
GB 2032472A
GB 7925304 A
GB7925304 A
GB 7925304A
GB 7925304 A
GB7925304 A
GB 7925304A
GB 2032472 A
GB2032472 A
GB 2032472A
Authority
GB
United Kingdom
Prior art keywords
fabric
beating
loosening
weft
power loom
Prior art date
1978-10-25
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Withdrawn

Application number
GB7925304A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

BUDAPESTI MUESZAKI EGYETEM

Budapesti Muszaki Egyetem

Original Assignee
BUDAPESTI MUESZAKI EGYETEM
Budapesti Muszaki Egyetem
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1978-10-25
Filing date
1979-07-20
Publication date
1980-05-08

1979-07-20
Application filed by BUDAPESTI MUESZAKI EGYETEM, Budapesti Muszaki Egyetem
filed
Critical
BUDAPESTI MUESZAKI EGYETEM

1980-05-08
Publication of GB2032472A
publication
Critical
patent/GB2032472A/en

Status
Withdrawn
legal-status
Critical
Current

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Classifications

D—TEXTILES; PAPER

D03—WEAVING

D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS

D03D49/00—Details or constructional features not specially adapted for looms of a particular type

D03D49/04—Control of the tension in warp or cloth

Abstract

A method of weaving comprises relieving the fabric tension at the time of beat-up, preferably by an amount equal to the tension produced by beat- up. The relief of tension is produced by rearwardly moving the breast beam 34′ (Fig. 6), by pivoting a fabric guide roller 34 (Fig. 5), by moving a guide roll 34” (Fig. 7) or by rotating the take- up roller.

Description

SPECIFICATION
A Weaving Process and a Power Loom for
Carrying Out the said Process
Background of the Invention
Field of the Invention
This invention concerns a weaving process and a power loom for carrying out the said process.
Description of the Prior Art
As is known, the formation of the fabric in power looms consists of opening a shed in the warp threads, inserting the weft threads into the shed, called picking, and beating-up of the weft by a beating element. The beating element of the loom for the shot of weft, e.g. a reed, presses the weft threads introduced between the warp threads against the selvage of the fabric. This operation takes place in a very short time and causes considerable stresses in the warp threads and structural stresses in the reed. Under the effect of beating-up by the reed, the fabric is loosened with a simultaneous attendant tensioning of the warp threads in which maximal tensile stresses occur at this time.Under the effect of these stresses and of the frictional and wear forces occurring in the warp-actuating parts of the loom, the warp thread may break, particularly in the case of densely woven fabrics.
To prevent or overcome breakage of the warp thread, the power loom has to be stopped. This causes, on the one hand, a serious loss of production due to down-time and, on the other hand, increases the workload of the operating personnel who usually mind several looms simultaneously; moreover, the above-mentioned peak stresses inherently exclude the application of certain raw materials of lower breaking strength which are in general cheaper and the usage of which would therefore be desirable.
Furthermore, practical experience shows that the magnitude of the tensile stresses generated in the warp threads during beating-up of the weft by the reed depends on the density of the weft in the fabric. The increase in the tensile stress in the warp thread caused by the beating-up of the weft may even limit the weft denisty of the fabric.
Summary of the Present Invention
An aim of this invention is to reduce or elininate these drawbacks.
Accordingly, the underlying task of this invention is to solve the above-mentioned problems by providing a weaving process, and a power loom for carrying out the process, by means of which the tensioning of the warp which occurs during beating-up of the weft can be reduced, consequently warp thread breakages and the consequent forced downtimes or stoppages in production may be reduced or eliminated and thus the productivity of the weaving may be increased.
The invention is based on the discovery that in the course weaving of the fabric, the forces required for the beating-up of the weft do not depend on the magnitude of the tensile stresses generated in the warp threads, but rather on the ratio of the tensile forces occurring in the warp and in the fabric during the beating-up of the weft. The problems may, therefore, be solved, or largely so, by reducing the tensioning of the fabric during the beating-up and thus optimising the ratio of the tensile forces occurring in the warp and in the fabric by presetting this ratio. In this way, the maximum tension of the warp thread on beating-up of the weft may be reduced substantially in comparison with known constructions or processes.Thus in the weaving process according to one aspect of the invention, a shed opening is formed by the warp threads in a per se known way, the weft is shot into the shed opening, then the weft is beaten up by a beating element, the essence of the invention being that the portion of the fabric situated before the weft thread is loosened during the beating-up.
Expediently, in the course of this loosening of the fabric the tensioning of the warp threads is kept at a constant level.
By these measures, it is ensured that the tensile force arising in those parts of the warp threads which are located behind the weft thread remain constant, compared with their state before the beating-up or, depending on the extent of loosening of the portion of fabric situated before the weft thread, this force increases to a substantially lesser extent than in the known solutions.
According to another aspect of the invention, this process may be carried out by a power loom comprising a per se known main shaft, a beating element co-operating with the main shaft, a fabric-tensioning unit adapted to be driven by the main shaft, and a fabric-loosening mechanism adapted to be driven by the main shaft and effective to operate the fabric-tensioning unit in the sense of slackening the tension during the beating-up.
According to a further preferred characteristic of the invention, the power loom provided with the fabric-loosening mechanism has a fabric guide element which can be displaced into a fabric-loosening position and which is arranged between the fabric tensioning unit and the beating element. This design makes a very simple constructional solution possible.
Furthermore, expediently the fabric guide element is formed as a cylinder which is angularly displaceably journalled on one end of a twoarmed lever the other end of which is linked by a pivot joint via a stroke adjusting mechanism to the reed leg. However, in another preferred embodiment, the fabric guide element is formed as a guide rail connected to the free end of a rocking arm pivoting around a fixed fulcrum, and a pair of cams on the main shaft co-operating with roller arms and cam followers displaceable about the fixed fulcrum wherein the roller arm is linked by a pivot joint to the rocking arm via a connecting rod that is preferably adjustable in length.
In the constructions described above, the pivoting of the fabric guide element of the fabric loosening mechanism can be effected by relatively simple mechanisms operating from the reed-leg or directly from the main shaft; moreover, the loosening of the fabric can be controlled by the stroke-adjusting mechanism or by the longitudinally adjustable connecting rod.
Brief Description of the Drawings:
The invention is further described purely by way of example, with reference to preferred embodiments illustrated in the accompanying schematic drawings, wherein:
Figure 1 and Figure 2 are force diagrams of the forces arising in known weaving processes;
Figure 3 and Figure 4 illustrate the interrelation of forces acting in the weaving process according to the invention;
Figure 5 shows a first preferred embodiment of the power loom according to the invention in fragmentary side view;
Figure 6 shows a second preferred embodiment of the power loom according to the invention, also in fragmentary side view; and
Figure 7 shows a third preferred embodiment of the power loom according to the invention in fragmentary side view.
Description of the Preferrred Embodiments:
In these Figures, identical parts are designated by identical reference numbers or symbols.
As can be seen in Figures 1 and 2, in the known weaving processes the weft thread 14 is being advanced along the direction of the arrow 1 8 between the transverse warp threads 10 and
12 by a beating element, in this case a reed 16, with a force Fe. In essence this constitutes the process of weaving. In the Figures, the fabric is designated by the reference number 20, the edge of the fabric or selvage by 21 , the direction of advance of the track or path of the fabric by 23.In accordance with the per se known requirements for the arrangement of the warp threads and the formation of the shed with the warp threads 10 and 12, the so-called basic tension of the portion of the warp threads situated in front of the weft thread 14 and of the portion of warp threads situated behind the weft thread 14, i.e. the value of the resultant of the tensile forces arising in these portions is identical (FL=Fs).This state before the beating-up is shown by a broken line in
Figure 2 where the portions of the warp threads
10, 12 situated in front of the weft thread 14 are designated by the reference numerals 1 ova, 12a,
respectively; and the forces arising in these
portions are designated by F1,, while the portions of the warp threads 10, 12 situated behind the weft thread 14 are designated by the reference
numerals lOb, 1 2b respectively and the forces
arising in these portions are designated by F,’.
Figure 2 shows that the tensile force Fs arising
in the fabric in the beating-up of the weft-which is equal with the sum of the horizontal components of the tensile forces F1 arising in the warp thread portions 1 Ob and 1 2b is reduced, while the force F1 equal to the sum of the horizontal components of the tensile forces arising in the warp thread portions 1 Oh, 1 2h increases to a peak value. The forces F1, F0 arising dunng the beating-up are indicated by a continuous thick line in Figure 2.Further, in the drawings, the angle included between the centre line 22 and the warp thread portions 1 Oa, 1 2a respectively is designated by A1, while the angle included between the centre line 22 and the warp thread portions 1 Oh, 1 2h respectively, is designated by 0.
The fundamental difference between the known solutions and the construction according to the invention (See Figures 3 and 4) is that the tensile force F0 arising in the warp thread portions 1 Oh, 1 2h respectively does not change or does not change substantially during the beating-up of the weft thread 14, because in the course of beating-up the tensile force Fs is decreased by reducing or loosening the tensioning in the warp thread portions 1 Oa and 1 2a by an amount which expediently equals the beating-up force Fe. If therefore the loosening force is equal to the beating-up force Fe, the tensile force F0 in the warp thread portions 1 orb and 12b remains unchanged, i.e. FL=Fs+FB- The power loom illustrated in Figure 5 is provided with a per se known beating element, in this case a reed leg 24, which is journalled on a reed shaft 26 for pivotal movement in the direction of the arrow 27. The reed leg 24 is connected with the main shaft 25 of the loom via a crank drive 28 in a per se known way.The power loom is also provided with a per se known fabric tensioning unit, in this case a fabric pulling cylinder 30, the function of which is to keep the fabric 20 tensioned and to wind it up.
According to this preferred embodiment of the invention, the power loom is provided with a fabricloosening or slackening mechanism 32 driven by the main shaft 25 to operate the fabric tensioning unit 30 in the sense of loosening (reducing) the tension of the fabric during the beating-up. Thus the object of this mechanism is to loosen the fabric 20 during beating.
The mechanism 32 may also be designed in such a way as to include a fabric guiding element which can be displaced into an end position for fabric loosening and which is arranged between the fabric tensioning unit 30 and the beating element. In the illustrated embodiment, however the fabric guide element is a cylinder 34, which is pivotaily journalled on one end of a two-arm lever 38. The fulcrum of the two-armed lever 38 is designated by the reference numeral 36. In this embodiment, the lower end of the two-armed lever 38 is connected to one end of a connecting rod 40 by a pivot linkage. The other end of the connecting rod (puil rod) 40 is connected to the reed leg 24, also by a pivot linkage. According to the invention a stroke-adjusting mechanism is inserted into the twd-armed lever 38.This strokeadjusting mechanism is, in this embodiment, a sliding block 42 included in the lever 38 with the aid of which the stroke of the reciprocating pivotal movement of the fabric guide cylinder 34 in the direction of the arrow 46 and thereby the extent of loosening the fabric 20 during the beating-up can be adjusted.
Thus the reed leg 24 moves during the beating in the direction of the arrow 27 drawn with a continuous line, consequently the fabric guide cylinder 34 of the fabric loosening mechanism 32 moves via connecting rod 40 and the two-armed lever 38 in the direction of the arrow 46 drawn with a continuous line, thus loosening the fabric 20 and consequently the warp thread portions 1 Oa and 1 2a by an amount regulated with the aid of the sliding block 42. On displacement of the reed leg 24 in the opposite sense, the cylinder 34 moves in the direction of the arrow 46 indicated by a broken line and the fabric 20 regains its basic state of tensioning.
Figure 6 illustrates another preferred embodiment wherein the weaving element is not shown separately. According to this embodiment of the invention, the fabric guide element 34′ is a guide rail connected to the free end of a pivot arm 50 pivoting around a fulcrum 52. A pair of cams 54 secured to the main shaft 25 in a perse known way cooperates with the rollers (followers) 58 mounted on a two-armed lever 56 pivoting around another fulcrum 60. In this embodiment, the lever 56 is connected via a connecting rod 62 and a pivot joint to the rocking arm 50. The rocking arm 50 is provided with a sliding block (not shown) and/or with a set of bores 64 to receive the pivot pin of the joint connecting the arm 50 with the rod 62.Depending on which of the bores 64 of the rocking arm 50 is connected with the connecting rod 62 the magnitude of the angular displacement of the fabric guide rail 34′ in the direction of the arrow 66 and thus the extent of loosening of the fabric 20 during beating-up can be regulated.
In another possible embodiment of the invention, the section of the fabric 20 between the selvage 21 and the guide rail 70 is supported by guide elements, e.g. in the embodiment illustrated in Figure 7, by two cylinders 68. In this embodiment, the fabric guide element is a cylinder 34″ forming part of the fabric loosening mechanism 32 which is arranged on the path of the fabric between the cylinders 68. The cylinder 34″ is moved upwardly or downwardly (Figure 7) via a connecting rod 72 and a perse known and hence non-illustrated drive with a stroke that is preferably adjustable e.g. with the aid of a pneumatic or hydraulic ram. During beating-up, the cylinder 34″ is moved upwardly thus loosening the fabric 20.
Within the scope of the invention it is also possible to provide an embodiment wherein the fabric-loosening mechanism 32 is combined with the fabric tensioning unit 30.
It must be emphasized that what is meant by the concept of loosening the portion of the weave or fabric which is situated before the weft thread during beating-up is that at least from the beginning of the contact between the beating element and the lastly shot-in or picked weft thread up to the completion of the beating, the portion of the fabric before the weft thread is loosened. This loosening may of course commence sooner, but the essence is that the portion of the fabric before the weft thread must be loosened.
Experiments carried out with the embodiments of the invention illustrated in the accompanying drawings have proved that the tension arising in the portion of warp threads situated behind the weft thread can be reduced by 50/52%, compared with traditional constructions. Thus the number of breaks of the warp threads and the attendant enforced production stoppages as well as the burden on the operator of the power loom may be reduced substantially and the weaving output may be increased. A further advantage of the preferred embodiments according to the invention is that the economic use of raw materials of lower tensile strength is made possible i.e. there is no need to use more expensive raw materials because of the stresses arising in beating-up. Moreover, the embodiments according to the invention enable fabrics of greater weft density to be produced from thread of identical tensile strength than would be possible with the known constructions.

Claims (10)

Claims

1. A weaving process, comprising forming a shed opening from warp threads, inserting a weft thread into the shed opening, and beating-up the weft by means of a beating element, wherein the improvement resides in that the portion of the fabric formed by warp and weft threads disposed before the very last weft thread is loosened during the beating-up of the weft.

2. A process according to claim 1, wherein during loosening of the fabric the tensioning force applied to the fabric is reduced by a force the magnitude of which is equal to that of the beating force.

3. A power loom adapted for carrying out the weaving process according to claim 1 or 2, comprising a main shaft, a beating element cooperating with the main shaft and a fabric tensioning device, wherein the improvement resides in the provision of a fabric-loosening mechanism for loosening the fabric during beating-up of the weft, said mechanism being connected to be driven by the main shaft and being effective to operate the fabric-tensioning device in the sense of loosening the fabric.

4. A power loom according to claim 3, wherein the fabric-loosening mechanism is provided with a fabric guide element arranged between the fabric-tensioning device and the beating-up element and means for displacing said guide element to a fabric loosening position.

5. A power loom according to Claim 4, wherein the said guide element is a cylinder which is pivotally journalled on one end of a two-armed lever, and the other end of the two-armed lever is connected by a pivot joint to the beating-up element.

6. A power loom according to Claim 5, wherein said beating-up element is a reed-leg connected to said lever via a stroke length setting mechanism.

7. A power loom according to claim 4, wherein the said guide element is a guide rail, which is connected to the free end of a rocking arm pivoting aroundd a first fixed fulcrum and is provided with cam means co-acting with cam follower means mounted on a lever pivoting around a second fixed fulcrum, the cam means being secured on the main shaft, and the said lever being connected by a pivot joint via a connecting rod to the rocking arm.

8. A power loom according to claim 7 wherein means are provided for adjusting the length of said connecting rod.

9. A process according to claim 1 or claim 2 substantially as herein described with reference to and as shown in Figures 3 and 4 or Figure 5 or
Figure 6 or Figure 7 of the accompanying drawings.

10. A power loom according to claim 3 substantially as herein described with reference to and as shown in Figures 3 and 4, or Figure 5 or
Figure 6 or Figure 7 of the accompanying drawings.

GB7925304A
1978-10-25
1979-07-20
Controlling Fabric Tension in Weaving Looms

Withdrawn

GB2032472A
(en)

Applications Claiming Priority (1)

Application Number
Priority Date
Filing Date
Title

HUBU000897

HU175887B
(en)

1978-10-25
1978-10-25
Weaving process and loom for carrying out the process

Publications (1)

Publication Number
Publication Date

GB2032472A
true

GB2032472A
(en)

1980-05-08

Family
ID=10994068
Family Applications (1)

Application Number
Title
Priority Date
Filing Date

GB7925304A
Withdrawn

GB2032472A
(en)

1978-10-25
1979-07-20
Controlling Fabric Tension in Weaving Looms

Country Status (9)

Country
Link

BG
(1)

BG39115A3
(en)

CH
(1)

CH643014A5
(en)

CS
(1)

CS223971B2
(en)

DE
(1)

DE2940527A1
(en)

FR
(1)

FR2439838A1
(en)

GB
(1)

GB2032472A
(en)

HU
(1)

HU175887B
(en)

IT
(1)

IT1119889B
(en)

PL
(1)

PL120714B1
(en)

Cited By (3)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

FR2505887A1
(en)

1981-05-12
1982-11-19
Alsacienne Constr Meca
Textile loom with automatic servo-control mechanism – for controlling position of breast beam

FR2538902A1
(en)

1982-12-29
1984-07-06
Vyzk Vyvojovy Ustav
Woven fabric tension measuring device

EP0352791A2
(en)

1988-07-27
1990-01-31
TSUDAKOMA Corp.
Seersucker weaving method and a seersucker loom

Families Citing this family (1)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

DE3905881C2
(en)

1989-02-25
1999-08-19
Dornier Gmbh Lindauer

Device for measuring warp tension in a weaving machine

Family Cites Families (4)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

US1595289A
(en)

1924-12-30
1926-08-10
Crompton & Knowles Loom Works
Terry-pile-fabric loom

US1629849A
(en)

1926-10-02
1927-05-24
John S Todd
Loom

FR1499476A
(en)

1966-09-27
1967-10-27
Sulzer Ag

Loom

CH543620A
(en)

1971-10-11
1973-10-31
Sulzer Ag

Method and device for weaving terry towels

1978

1978-10-25
HU
HUBU000897
patent/HU175887B/en
unknown

1979

1979-07-20
GB
GB7925304A
patent/GB2032472A/en
not_active
Withdrawn

1979-09-10
CH
CH812879A
patent/CH643014A5/en
not_active
IP Right Cessation

1979-10-05
FR
FR7924830A
patent/FR2439838A1/en
active
Granted

1979-10-05
DE
DE19792940527
patent/DE2940527A1/en
not_active
Withdrawn

1979-10-10
CS
CS687779A
patent/CS223971B2/en
unknown

1979-10-16
BG
BG4516379A
patent/BG39115A3/en
unknown

1979-10-23
IT
IT5064679A
patent/IT1119889B/en
active

1979-10-24
PL
PL21917279A
patent/PL120714B1/en
unknown

Cited By (4)

* Cited by examiner, † Cited by third party

Publication number
Priority date
Publication date
Assignee
Title

FR2505887A1
(en)

1981-05-12
1982-11-19
Alsacienne Constr Meca
Textile loom with automatic servo-control mechanism – for controlling position of breast beam

FR2538902A1
(en)

1982-12-29
1984-07-06
Vyzk Vyvojovy Ustav
Woven fabric tension measuring device

EP0352791A2
(en)

1988-07-27
1990-01-31
TSUDAKOMA Corp.
Seersucker weaving method and a seersucker loom

EP0352791A3
(en)

1988-07-27
1991-09-18
TSUDAKOMA Corp.
Seersucker weaving method and a seersucker loom

Also Published As

Publication number
Publication date

PL120714B1
(en)

1982-03-31

BG39115A3
(en)

1986-04-15

FR2439838B1
(en)

1985-03-08

IT1119889B
(en)

1986-03-10

FR2439838A1
(en)

1980-05-23

PL219172A1
(en)

1980-06-16

IT7950646D0
(en)

1979-10-23

CS223971B2
(en)

1983-11-25

DE2940527A1
(en)

1980-05-08

CH643014A5
(en)

1984-05-15

HU175887B
(en)

1980-11-28

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