GB2334266A

GB2334266A - Apparatus for driving a needling machine

Info

Publication number: GB2334266A
Application number: GB9900636A
Authority: GB
Inventors: Heinz Hofholzer; Augustin Kalteis
Original assignee: Textilmaschinenfabrik Dr Ernst Fehrer AG
Current assignee: Textilmaschinenfabrik Dr Ernst Fehrer AG
Priority date: 1998-02-12
Filing date: 1999-01-12
Publication date: 1999-08-18
Also published as: TW404996B; AT405534B; ITGE990012A1; IT1309456B1; ATA25198A; DE19860889A1; FR2774705A1; JPH11315464A

Abstract

An apparatus for driving a needling machine with a plurality of needling means which can be driven by electric motors (1) and which are controlled with respect to their mutual angular position by a control means (5) and are fed by an a.c. power supply (3) is characterised in that the motors (1) are connected to a common d.c. link (4) together with a drive (11) for a flywheel (12), where the drive may operate as a motor or as a generator depending on load conditions. Under normal conditions, the drive acts as a motor and stores energy in the flywheel. If there is a mains power failure, the drive (11) acts as a generator and the energy stored in the flywheel (12) may be fed into the common d.c. link (4) to the electric motors (1) to ensure a synchronous slow-down of the needling means. The control means (5) can monitor the flow of energy through static power converters (2) associated with the drives to recognise and correct errors. The feed drive (8) for the web is similarly connected to the a.c. power supply (3) and the d.c. link (4).

Description

j 2334266 Apparatus for Driving a Needling Machine This invention relates

to an apparatus for driving a needling machine with a piurality of needling means which can be driven by means of electric motors controlled with respect to their mutual angular position and fed via an a.c. power supply.

When the needling means of a needling machine are not driven via a common main drive, but via individual electric drives, a synchronous operation of the electric motors used for driving the needling means must be ensured, so as to ensure that the needles of the needling means arranged one behind the other in direction of web movement stitch into the web at the same time, because otherwise the web feed would be impeded by the web not being released simultaneously by the needles. When providing such individual drives, a control of the electric motors with respect to their mutual angular position therefore becomes necessary. When the needling machine is switched off, this control of the mutual angular position of the electric motors must also remain effective while the machine slows down to a standstill of the needling means, unless damages of the web disposed in the vicinity of the needling means must be accepted.

While the slow-down control of the electric motors creates no difficulties in the case of an energy supply via the mains input, a mains failure will also lead to a failure of this control with the result that the individual needling means slow down independent of each other, and due to the different inertial forces fall out of step.

It is therefore the object underlying the invention to create an apparatus for driving a needling machine as described above such that a proper shut-down of the needling machine can also be ensured M the case of a mains failure, without having to fear a damage of the web.

This object is solved by the invention in that the electric motors for driving the needling means are connected to a common d.c. link together with a drive for a flywheel which can be operated as motor or as generator in dependence on its load conditions.

By providing a correspondingly dimensioned flywheel, a drive energy sufficient for a synchronous slow-down of the individual needling means can be stored, and in the case of a mains failure this drive energy can be fed into the common d.c. link as electric energy via the drive motor for the flywheel, because under these load conditions the drive for the flywheel takes effect as generator. Via the common d.c. link the connected electric motors for the individual needling means can thus also be supplied with electric energy, so that a synchronous slow-down of the needling means is ensured by maintaining the drive control. Since both the electric motors for driving the needling means and the drive for the flywheel are activated on the one hand at the a.c. power supply and on the other hand at the common d.c. link via a.c. converters, the function of the individual drives can be monitored by means of the respective flow of energy through the static power converters associated to the individual drives, so that errors in the vicinity of the individual drives can be recognized and in response thereto corresponding manipulations of the machine control can be performed. Due to this possibility for a constant monitoring, the functional reliability in the case of a possible mains failure is ensured in a simple way.

It need probably not be emphasized in particular that for a proper slowdown of the needling machine the feed drive of the web must also be controlled correspondingly. It is therefore recommended to likewise connect the feed drive for the web to the common d.c. link.

In the drawing, the subject-matter of the invention is represented by way of example, and there is shown an inventive apparatus for driving a needling machine in a schematic block circuit diagram.

For driving the individual needling means, which in a conventional way consist of needle boards reciprocatingly movable in stitching direction of the needles via eccentric drives, four electric motors 1 are provided in accordance with the embodiment, whose speed is infinitely variable. These electric motors 1 are connected via static power converters 2 to an a. c. network 3 on the one hand and to a common cl.c. link 4 on the other hand. To obtain a synchronous lifting movement of the needle boards of the individual needling means, the electric motors 1 must be controlled with respect to their mutual angular position. For this purpose, a control means 5 is provided, to which the actual values of the respective angular position of the rotors of the individual electric motors are supplied via rotary-step transducers 6. In the case of a difference between the desired value and the actual value, the static power converter circuit 2 associated to the electric motor 1 to be controlled is activated via a control signal line 7 in the sense of a balancing of desired value and actual value, and the associated electric motor 1 is returned to the desired value.

The feed drive for the web has a gear motor 8, which is in drive connection with a feed roller and via a static power converter circuit 2 is likewise connected to the a.c. power supply 3 on the one hand and to the d.c. link 4 on the other hand. For controlling the speed of this gear motor 8, this motor 8 has a speed sensor 9, by means of which the actual speed values can be detected by the control means 5, so as to perform a possibly necessary control manipulation via the static power converter circuit 2 after a comparison of desired and actual values. The control signal fine provided for this purpose is designated with 10.

In addition to the motors 1 and 8 required for the drive of the needling machine there is provided an additional drive 11 for a flywheel 12, which like the other motors 1 and 8 is connected to a static power converter circuit 2, by means of which it is connected with the a.c. power supply 3 and the d.c. link 4. Depending on its load conditions, the drive 11 can be operated as motor or as generator, depending on whether the drive 11 drives the flywheel 12 or the flywheel 12 drives the drive 11. For storing a predetermined drive energy in the flywheel 12, the drive 11 operated as motor must have a corresponding speed. For this reason, the drive 11 is subjected to a speed control in the motor range, where a speed sensor 9 is provided to detect actual values. The possibly necessary control intervention is effected via a control line 13, which serves to activate the static power converter circuit 2.

The d.c. link 4 is not only used for an advantageous energy compensation between the individual drives during the normal operation of the needling machine, but also for an emergency power supply in the case of a mains failure. In the case of a mains failure, the inertial forces of the flywheel 12 effect a generator operation of the drive 11, so that, if necessary, the drive energy stored in the centrifugal mass of the flywheel 12 can be fed as electric energy into the d.c. link 4 via the static power converter circuit 2. By means of this recovered energy, the electric motors 1 and the gear motor 8 can be operated in a controlled way for a synchronous slow-down of the needling means, which provides for a proper shut-down of the needling machine, without having to use an expensive emergency power supply. Since in addition the flow of energy between the a.c. power supply 3, these motors 1, 8 and 11 as well as the d.c. link 4, which depends on the load of the individual motors 1, 8 and 11, can be monitored by means of the individual static power converter circuits 2, the operability of the individual motors 1, 8 and 11 can constantly be derived from this flow of energy, so that occurring errors are recognized in due time and corresponding counter-measures can be taken.

Claims

C 1 a i m s

An apparatus for driving a needling machine with a plurality of needling means, which can be driven by electric motors which are controlled with respect to their mutual angular position and are fed via an a.c. power supply, characterized in that for driving the needling means the electric motors are connected to a common d.c. link together with a drive for a flywheel which drive can be operated as motor or as generator in dependence on its load conditions.
2. Apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawing.