GB1593033A - Control of warp and cloth tensions in weaving looms - Google Patents

Description

(54) CONTROL OF WARP AND CLOTH TENSIONS IN WEAVING LOOMS (71) We, SCAPA ENGINEERING LIM ITED, a British Company of Cartmell Road, Blackburn, BB2 2SZ, Lancashire, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention concerns the control of warp and cloth tensions in weaving looms, and has more particular reference to a means for controlling such tensions.

The conventional practice in controlling the tension of the warp yarns in a weaving loom is to provide a friction brake or brakes operating on the warp beam to resist rotation thereof, whilst in the case of the woven cloth the practice is to use a system of loaded weights which operate ratchet wheels or like mechanisms coupled to the cloth roller to effect rotation thereof.

Whilst the arrangements as aforesaid have been in use for many years, they are not wholly satisfactory in that they do not provide for a close and uniform control of tension.

The object of the present invention is to provide a more satisfactory control system than that hitherto used.

According to the present invention there is proposed a drive arrangement for the warp let-off and cloth take-up rolls of a weaving loom which comprises a first drive means releasably connectable with each of the said rolls, a second drive means releasably connectable with each of the said rolls, and control means for selectively connecting the let-off and take-up rolls with the first drive means or each with a respective one of the first and second drive means.

The invention will now be described further, by way of example only, with reference to the accompanying diagrammatic drawings illustrating one embodiment thereof, and in which Fig. 1 is a schematic illustration of a drive arrangement for use in controlling the warp and/or cloth tensions in a weaving loom; and Fig. 2 is a block diagram showing the electrical interconnection of the various integers as included in the arrangement shown in Fig. 1.

Referring now to the drawing, and particularly to Fig. 1 thereof, a change gear box 11 driven from the weaving loom (not shown) via an input shaft 12 drives a geared speed reduction unit 13 for the warp let-off rollers (not shown) of the loom through a variable gear unit 14 and an electro-magnetic clutch 15, the output shaft 16 of reduction unit 13 being connected with the warp rollers. Gear box 11 also drives a geared speed reduction unit 17 for the cloth take-up rollers (not shown) through an electro-magnetic clutch 18, reduction unit 17 being connected with the cloth take-up rollers through an output shaft 19.

An electro-magnetically controlled torque motor 20 is drivingly connected with speed reduction unit 13 through a geared speed reduction unit 21, a chain drive 22, an electro-magnetic clutch 23 and a further chain drive 24, whilst such motor 20 is connected with speed reduction unit 17 through speed reduction unit 21, chain drive 22, an electro-magnetic clutch 25 and a chain drive 26.

A rapid wind/unwind motor 27 is provided in the drive to unit 13, whilst a further such motor 28 is provided in the drive to unit 17, motor 27 being positioned between chain drive 24 and unit 13 and motor 28 being between chain drive 26 and unit 17.

An electro-magnetic brake 29 is provided between chain drive 24 and motor 27, and a further electro-magnetic brake 30 is provided between clutch 25 and chain drive 26, brakes 29 and 30 being applied automatically when power thereto is switched off.

As will be appreciated. by suitably control ling the condition and combination of conditions of electro-magnetic clutches 15, 18, 23 and 25, so the drive from change gear box 11 or from torque motor 20 can be selectively applied to the warp let-off rollers through shaft 16 or to the cloth take-up rollers through shaft 19.

Thus, assuming rapid wind/unwind motors 27, 28 to be idling, and with the electromagnetic brakes 29, 30 energised, the following drive tranmission situations can be selected: (1) With electro-magnetic clutches 15 and 18 energised, both warp let-off and cloth winding rollers are positively driven from the loom through gearbox 11 at rates determined by variable gear unit 14 and a reduction unit 13, on the one hand, and reduction unit 17, on the other hand. An infinite variation of the ratio of warp length feed to cloth length take-up can be effected by virtue of the variable gear unit, thereby to meet the needs of any particular cloth construction.

(2) with electro-magnetic clutches 18 and 23 energised, the cloth take-up rollers are positively driven at the rate required from the loom through gearbox 11, clutch 18 and reduction unit 17, whilst the warp let-off rollers are driven by torque motor 20 via reduction unit 21, chain drive 22, clutch 23, chain drive 24 and reduction unit 13. By suitable adjustment of torque motor 20, so the warp tension may be maintained at a preset level.

(3) With electro-magnetic clutches 15 and 25 energised, the warp let-off rollers are positively driven from the loom through gear box 11, clutch 15 and reduction unit 13, whilst the cloth take-up rollers are driven from torque motor 20 via reduction unit 21, chain drive 22, clutch 25, chain drive 26 and reduction unit 17, the cloth tension being maintained at a pre-set level by suitable setting of the torque motor.

A typical circuit diagram for use in connection with the drive means shown in Fig. I is illustrated in Fig. 2. Thus, referring now to Fig. 2, in which like reference numerals to those of Fig. I are used for the same or similar parts, the circuit includes a master control unit 32 having a three position switch 33 therein, whereby the energisation of the electro-magnetic clutches 15, 18. 23 and 25 and the electro-magnetic brakes 29, 30 in combination appropriate to situations (1) (2) and (3) above might be effected.

The master control unit 32 is connected with a three phase power source 34 through a two position switch 35, such switch providing for selection between a setting wherein the fast wind/unwind motors cannot be used and a setting wherein the electronic control for the torque motor is disconnected and the loom cannot operate.

The electro-magnetic clutches 15. IX, 23, 25 are connected with the master control unit as at 15', 18', 23' and 25', whilst the electromagnetic brakes 29, 30 are connected to such unit as at 29', 30'.

The diagram shows the further provision of a load indicator 36, a regulator 37 for the required cloth tension, a load cell 38 sensitive to and activated directly by cloth tension and an indicator light 39 for indicating when negative let-off or take-up is in operation, all coupled with the master control unit 32, such unit also including electronic equipment for the load cell 38 and control of the torque motor 20, and a rectifier to provide power for such torque motor.

A fast motor control 40 connects the rapid wind/unwind motors with the three phase source through the two position switch 35.

The invention is not restricted to the exact features of the embodiment hereinabove disclosed, since alternatives will readily present themselves to one skilled in the art.

Thus, for example, instead of controlling the operation of the arrangement by reference to cloth tension, means may be provided for sensing warp tension and for controlling the arrangement by reference to such tension.

Alternatively, both cloth and warp tensions may be monitored and control of the arrangement based on the differential therebetween.

As will be appreciated, by means of the arrangement herein proposed, we are able readily to control the warp let-off and cloth take-up motions in accordance with specific requirements and in such manner that the relationship therebetween is maintained constant as the weaving process continues.

WHAT WE CLAIM IS: 1. A drive arrangement for the warp letoff and cloth take-up rolls of a weaving loom comprising a first drive means releasably connectable with each of the said rolls, a second drive means releasably connectable with each of the said rolls, and control means for selectively connecting the let-off and take-up rolls with the first drive means or each with a respective one of the first and second drive means.

2. A drive arrangement as claimed in claim I, wherein the said first drive means is connectable with each of the said rolls via a respective electro-magnetic clutch means.

3. A drive arrangement as claimed in claim 2, wherein a variable gear unit is provided in the drive transmission from the first drive means to either or both of the rolls.

4. A drive arrangement as claimed in claim 3, wherein a single variable gear unit is provided and is located in the drive transmission to the warp let-off roll.

5. A drive arrangement as claimed in any one of claims 2 to 4, wherein the second drive means is connectable with each of the said

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (14)

**WARNING** start of CLMS field may overlap end of DESC **. ling the condition and combination of conditions of electro-magnetic clutches 15, 18, 23 and 25, so the drive from change gear box 11 or from torque motor 20 can be selectively applied to the warp let-off rollers through shaft 16 or to the cloth take-up rollers through shaft 19. Thus, assuming rapid wind/unwind motors 27, 28 to be idling, and with the electromagnetic brakes 29, 30 energised, the following drive tranmission situations can be selected: (1) With electro-magnetic clutches 15 and 18 energised, both warp let-off and cloth winding rollers are positively driven from the loom through gearbox 11 at rates determined by variable gear unit 14 and a reduction unit 13, on the one hand, and reduction unit 17, on the other hand. An infinite variation of the ratio of warp length feed to cloth length take-up can be effected by virtue of the variable gear unit, thereby to meet the needs of any particular cloth construction. (2) with electro-magnetic clutches 18 and 23 energised, the cloth take-up rollers are positively driven at the rate required from the loom through gearbox 11, clutch 18 and reduction unit 17, whilst the warp let-off rollers are driven by torque motor 20 via reduction unit 21, chain drive 22, clutch 23, chain drive 24 and reduction unit 13. By suitable adjustment of torque motor 20, so the warp tension may be maintained at a preset level. (3) With electro-magnetic clutches 15 and 25 energised, the warp let-off rollers are positively driven from the loom through gear box 11, clutch 15 and reduction unit 13, whilst the cloth take-up rollers are driven from torque motor 20 via reduction unit 21, chain drive 22, clutch 25, chain drive 26 and reduction unit 17, the cloth tension being maintained at a pre-set level by suitable setting of the torque motor. A typical circuit diagram for use in connection with the drive means shown in Fig. I is illustrated in Fig. 2. Thus, referring now to Fig. 2, in which like reference numerals to those of Fig. I are used for the same or similar parts, the circuit includes a master control unit 32 having a three position switch 33 therein, whereby the energisation of the electro-magnetic clutches 15, 18. 23 and 25 and the electro-magnetic brakes 29, 30 in combination appropriate to situations (1) (2) and (3) above might be effected. The master control unit 32 is connected with a three phase power source 34 through a two position switch 35, such switch providing for selection between a setting wherein the fast wind/unwind motors cannot be used and a setting wherein the electronic control for the torque motor is disconnected and the loom cannot operate. The electro-magnetic clutches 15. IX, 23, 25 are connected with the master control unit as at 15', 18', 23' and 25', whilst the electromagnetic brakes 29, 30 are connected to such unit as at 29', 30'. The diagram shows the further provision of a load indicator 36, a regulator 37 for the required cloth tension, a load cell 38 sensitive to and activated directly by cloth tension and an indicator light 39 for indicating when negative let-off or take-up is in operation, all coupled with the master control unit 32, such unit also including electronic equipment for the load cell 38 and control of the torque motor 20, and a rectifier to provide power for such torque motor. A fast motor control 40 connects the rapid wind/unwind motors with the three phase source through the two position switch 35. The invention is not restricted to the exact features of the embodiment hereinabove disclosed, since alternatives will readily present themselves to one skilled in the art. Thus, for example, instead of controlling the operation of the arrangement by reference to cloth tension, means may be provided for sensing warp tension and for controlling the arrangement by reference to such tension. Alternatively, both cloth and warp tensions may be monitored and control of the arrangement based on the differential therebetween. As will be appreciated, by means of the arrangement herein proposed, we are able readily to control the warp let-off and cloth take-up motions in accordance with specific requirements and in such manner that the relationship therebetween is maintained constant as the weaving process continues. WHAT WE CLAIM IS:

1. A drive arrangement for the warp letoff and cloth take-up rolls of a weaving loom comprising a first drive means releasably connectable with each of the said rolls, a second drive means releasably connectable with each of the said rolls, and control means for selectively connecting the let-off and take-up rolls with the first drive means or each with a respective one of the first and second drive means.

2. A drive arrangement as claimed in claim I, wherein the said first drive means is connectable with each of the said rolls via a respective electro-magnetic clutch means.

3. A drive arrangement as claimed in claim 2, wherein a variable gear unit is provided in the drive transmission from the first drive means to either or both of the rolls.

4. A drive arrangement as claimed in claim 3, wherein a single variable gear unit is provided and is located in the drive transmission to the warp let-off roll.

5. A drive arrangement as claimed in any one of claims 2 to 4, wherein the second drive means is connectable with each of the said

rolls via a respective electro-magnetic clutch means.

6. A drive arrangement as claimed in claim 5, wherein the second drive means comprises a torque motor.

7. A drive arrangement as claimed in claim 6, further including a load cell sensitive to cloth tension for control of the second drive means in correspondence with such tension.

8. A drive arrangement as claimed in any one of the preceding claims, further including a respective rapid wind/unwind motor in the drive transmission to each roll.

9. A drive arrangement as claimed in claim 1, wherein the respective drive transmission means between the first and second drive means and each roll comprises an electro-magnetic clutch, the pair of clutches associated with each respective roll being drivingly connected at the output side thereof.

10. A drive arrangement as claimed in claim 9, wherein the drive transmission means between the first drive means and each respective roll includes a speed reduction unit, each such speed reduction unit being provided at the output side of the clutch.

11. A drive arrangement as claimed in claim 9 or 10, wherein the second drive means comprises a torque motor.

12. A drive arrangement as claimed in claim 11, including a load cell sensitive to cloth tension, for controlling operation of the torque motor.

13. A drive arrangement for the warp letoff and cloth take-up rolls of a weaving loom substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

14. A weaving loom having a drive arrangement as claimed in any one of claims 1 to 13.