GB2085488A

GB2085488A - A drive arrangement for a loom

Info

Publication number: GB2085488A
Application number: GB8131281A
Authority: GB
Original assignee: Kombinat Textima VEB
Current assignee: Kombinat Textima VEB
Priority date: 1980-10-16
Filing date: 1981-10-16
Publication date: 1982-04-28
Also published as: DD153612A1; BE890737A; CH651863A5; CS253256B1; GB2085488B; DE3131605A1; FR2492422B1; FR2492422A1; NL8104027A; SU1164334A1

Abstract

A drive arrangement for a loom comprises a single asynchronous motor 2 having an output shaft 3 directly connected to the input part of an induction clutch 4, the output shaft 5 of which is supported in pillow blocks 6, 7 and is connected to a tacho-generator 13 constructed as a speed counter element of a control circuit which controls the force field in the induction clutch 4, the shaft 5 driving the main driving shaft by a reduction V-belt drive 8, 9, 11. The induction clutch 4 providing inching and creeping as well as main drive. <IMAGE>

Description

SPECIFICATION A drive arrangement for a loom This invention relates to a drive arrangement for a loom.

A drive arrangement for looms is known which consists essentially of a flywheel with a motor drive, an electromagnetic clutch between this flywheel and a shaft and a planetary gear between this shaft and the crankshaft of the loom itself, the crankshaft carrying differential wheels (German Offenlegungsschrift 22 08 387).

A further known drive arrangement for looms is so constructed that an electromagnetic clutch and an electromagnetic brake are arranged between the driving motor and the crankshaft. In this respect a single disc clutch and a single disc brake are preferably used. A common armature disc is associated with the clutch and brake field. A second electromagnetic brake is provided in a planetary gear which is also arranged between the driving motor and the crankshaft (German Utility Model 1 9 59 798). These drive devices with electromagnetic clutches, flywheels and planetary gears are disadvantageous on account of the high degree of mechanical complexity. Moreover, early wear of the gears and clutch must be taken into account as a result of the stress which takes place.

Further drawbacks consist in that there is a fixed ratio between the rated operating speed and the creeping operating speed, on-load starting is difficult and there is no retaining torque of the brake in the condition in which voltage is not applied.

It is an object of the invention to obviate the above drawbacks and therefore considerably increase the quality of the entire drive.

The invention aims at providing a drive arrangement for looms which operates with a high degree of efficiency and ensures a long service life with an economic arrangement of the drive elements.

Accordingly, the present invention consists in a drive arrangement for a loom, comprising a main driving shaft having a stub on which is mounted a two-surface friction disc brake, a single asynchronous motor having an output shaft driven at one speed for both rated speed and creeping speed operation of the loom, an induction clutch having an output part with a shaft and an input part directly connected to the output shaft of the motor, a tachogenerator cooperating with the induction clutch, and a control circuit, the main driving shaft being operatively connected to the output shaft of the clutch via a reduction V-belt drive. Advantageously, the tachogenerator is constructed as speed counter element of the control circuit with the output shaft of the induction clutch and controls the force field in the induction clutch.Preferably, the creeping speed and heavy on-load starting of the loom is selectable manually and steplessly by varying the nominal value of the control circuit.

In order that the invention may be more readily understood, reference is made to the accompanying drawing which shows diagrammatically and by way of example a simplified side view of the drive device in accordance with the invention.

An asynchronous squirrel cage motor 2 is fastened to the loom frame 1, the output shaft 3 of this motor being directly connected to the input part of an induction clutch 4. The output part of the induction clutch 4 has a shaft 5 which is supported in pillow blocks 6, 7 and carries a V-belt pulley 8 which drives via V-belts 9 a pulley 11 mounted on the main drive shaft 10 of the loom. A two-surface friction disc brake 12 is mounted directly on the stub of the main drive shaft 10. A tachogenerator 13 constructed as a speed counter element of a control circuit for receiving the angular speed of the output shaft 5 is mounted such that it may be pivoted together with the pillow block 7 in order to enable a rapid exchange of V-belts or the fastening of a hand wheel.

The direct connection of the induction clutch 4 to the shaft 3 of the asynchronous squirrel cage motor 2 ensures a clutch operation with the high speed of the motor 2. The induction clutch 4 therefore has an improved dynamic operation and only needs to be rated with respect to its constructional size in accordance with the torque corresponding to the high speed. The tachogenerator 1 3 controls, as a speed counter element, in the control circuit which is not described in further detail, the actuation of the induction clutch 4 in such a way that in the case of creeping operation and heavy on-load starting of the loom the driving speed remains within the control deviation despite the torque development which is changing to a large extent.The positioning of the two-surface friction disc brake 12 on the stub of the main drive shaft 10 driven by the V-belt pulley 11 enables the braking operation to be carried out in accordance with the speed reduction and therefore decreases the wear of the brake.

In the dimensioning of the two-surface friction disc brake 12 there should be taken into account firstly the crank angle of the respective loom which is available from the response of a monitoring device to the standstill position of the loom and secondly the stored energy of the loom.

This two-surface friction disc brake 1 2 enables braking of the loom without any auxiliary power from outside. The two-surface friction disc brake 12 may be mechanically eased for assembly and setting purposes by screwing in two screws. The induction clutch 4 is provided with an appropriate protective covering in order to attenuate noise in the case of high differential speeds and to maintain the required degree of protection.The drive device provides substantial advantages in use, such as: - enabling creeping and rated operation of the loom by a high differential speed setting on the induction clutch 4, - the use of a single asynchronous squirrel cage motor 2 having a single speed and a single induction clutch 4 for two operating speeds of the main shaft 10, - a clutch operation with an extremely low degree of wear, as the torque is transmitted to the induction clutch 4 by an electrically controllable force field and is not positively or frictionally connected, - on-load starting of the loom by the induction clutch 4 which is energy saving and uniformly gentle, - protection of all the drive elements as a result of the resilient and vibration attenuating properties of the induction clutch 4 which also has an advantageous effect on the weaving process, - the selection of a stepless creeping speed, adapted to the weaving conditions and the operator, by the operator himself, - the possibility of steplessly ascertaining the optimum rated speed in the setting operation for the textile material, - the sensitivity of the loom movement in the case of inching may be optimally achieved by an admissible short over-excitation of the induction clutch 4, - if voltage is switched off or power discontinued to the two-surface friction disc brake, the latter is actuated, stops the loom and satisfies the technical safety requirements, any uncontrolled movement from the standstill position, as occurs in the case of Jacquard machines, is excluded in the energised condition by the retaining torque of the twosurface friction disc brake 12, - simple operation and low maintenance costs are ensured by the use of few and robust drive elements, - the electrical control of all the elements of the drive enables inching, single weft picking and the automatic running of partial operating programmes, - subjective factors providing physical difficulties in operation are countered by the use of push button switches.

Claims

1. A drive arrangement for a loom, comprising a main driving shaft having a stub on which is mounted a two-surface friction disc brake a single asynchronous motor having an output shaft driven at one speed for both rated speed and creeping speed operation of the loom, an induction clutch having an output part with a shaft and an input part directly connected to the output shaft of the motor, a tachogenerator cooperating with the induction clutch, and a control circuit, the main drivirig shaft being operatively connected to the output shaft of the clutch via a reduction V-belt drive.

2. A drive arrangement as claimed in claim 1, wherein the tachogenerator is constructed as a speed counter element of the control circuit, is connected to the output shaft of the induction clutch and controls the force field in the induction clutch.

3. A drive arrangement as claimed in claim 1 or 2, wherein creeping speed and heavy on-load starting of the loom is selectabie manually and steplessly by varying the nominal value in the control circuit.

4. A drive arrangement for looms, substantially as herein described with reference to and as shown in the accompanying drawing.