EP0229122A1

EP0229122A1 - Warp knitting loom.

Info

Publication number: EP0229122A1
Application number: EP86904088A
Authority: EP
Inventors: Karl Denzler; Alfred Bohm; Adolf Hagel; Rudi Wirth
Original assignee: LIBA Maschinenfabrik GmbH
Current assignee: LIBA Maschinenfabrik GmbH
Priority date: 1985-07-03
Filing date: 1986-07-03
Publication date: 1987-07-22
Anticipated expiration: 2006-07-03
Also published as: WO1987000216A1; US4736602A; JPS63500045A; EP0229122B1; DE3523794C1; JPH0137500B2

Abstract

Dans un métier de tricotage en chaîne, les outils de tricotage et chaque ensouple (3) sont actionnés chacun par leur propre moteur électrique (20), qui sont tous alimentés par un seul réseau commun. Un embrayage à commande électrique et connecté au réseau est agencé dans la transmission entre chaque ensouple (3) et le moteur électrique (20) correspondant. Cet embrayage (15, 16) est enclenché par la tension du réseau et déclenché en l'absence de tension.In a warp knitting craft, the knitting tools and each beam (3) are each actuated by their own electric motor (20), which are all powered by a single common network. An electrically controlled clutch connected to the network is arranged in the transmission between each beam (3) and the corresponding electric motor (20). This clutch (15, 16) is engaged by the network voltage and triggered in the absence of voltage.

Description

B e ε b r e i b u n g

Warp knitting machine

The invention relates to a warp knitting machine in which the weaving tools and each warp beam in each case driven by a separate, fed from a common power electric motor ^".

Such a drive for a warp knitting machine is described in DE-PS 30 25 782. This patent indicates that in the event of a power failure, the main shaft of the machine and the parts connected to it only come to a standstill with a certain delay due to their mass and high speed, while the drive of the warp beam or the drives of the warp beams are relative stop quickly. This means that all warp threads of all warp beams can tear. In order to eliminate this danger, a circuit is described in the patent specification according to which an electrically actuable brake, also connected to the mains, is assigned to the main shaft of the machine. In the event of a mains failure, the brake from its release position to its braking position under the influence of a stored braking force goes. This ensures that the main shaft comes to a standstill in a much shorter time, almost suddenly, thereby avoiding the warp threads being torn off. During this almost sudden braking of the main shaft Given the considerable masses associated with the main shaft, the relevant components are subjected to high loads, which can lead to internal displacements in the machine and even damage. In this loading machine utilization is addressed also einge¬ in the patent, namely the fact that an additional circuit will be ange¬ to give ineffective in the case of a normal brake above described turn-off ^', wo¬ by the near instantaneous stopping of the Main shaft is avoided in this normal operating case. However, the load on the machine that arises in the event of a power failure cannot be eliminated in this way.

It should also be referred to US-PS 26 25 021, in which

In connection with a warp knitting machine with a drive derived from the main shaft for the warp beam, an electrically operable coupling is disclosed, which is to ensure that the. Warp beam at - by setting a more or less strong drive via the coupling. Changes in the thread tension supply more or less drive energy in order to thereby always keep the thread tension at its normal value.

The object of the invention is to eliminate the risk of the warp threads tearing off in the event of a power failure, without exposing the machine to a particular load. According to the invention, this is done in that in the drive connection between each warp beam and the electric motor in question there is an electrically actuable coupling which is connected to the mains and can be engaged by the mains voltage and disengages when it is removed.

Due to the clutch disengaging in the event of a power failure and the resulting disconnection of the drive connection between The electric motor and warp beam eliminate the risk of the warp threads tearing, since the warp beam (s) can continue to rotate without further effort due to the tensile stress exerted on them by the knitting tools until the knitting tools are also stopped when the main shaft is at a standstill . The main shaft can run out under the effect of its moments of inertia, so that the main shaft and the components connected to it are not exposed to any particular loads. Experience has shown that this mode of operation is completely harmless for the warp threads, since in this operating mode the warp beam is in any case rotating and the frictional forces exerted on it are always kept as small as possible due to its mounting, so that they continue to be used by the knitting tools drawn warp threads can easily rotate the warp beam. This friction may well be desirable, since it counteracts the tendency of the warp beam to continue turning due to this imbalance, in particular if the warp beam is unbalanced.

Another important advantage of interrupting the drive connection between the electric motor and the warp beam is that the knitting tools that continue to work in the event of a power failure automatically cause the necessary synchronization between the main shaft and the warp beam or warp beam due to their pull on the warp threads and the following of the warp beams that special means are required. This synchronization is made more difficult in the event of the main shaft being almost suddenly stopped according to the prior art discussed above, since it can be assumed that the drives of the warp beams cease their activity immediately. For this reason, DE-PS 30 25 782 also refers to a preferred embodiment, according to which the number of follow-up revolutions of the main shaft is only 1 to 2. _In this way, the high speed of braking the main shaft approximates synchronization between the main shaft and warp beams, but this is at the expense of the machine because of the speed of braking. The principle of the conscious outlet omission of the main shaft in the case of power failure according to the vor¬ lying _^ invention thus represents with its supplementary measure the interruption of the drive connection zwi¬'s electric motor and warp beam and the consequent ER- imaging automatic synchronization between Haupt¬ wave and the warp beam a fundamental departure from the basic idea disclosed in DE-PS 3025 782.

Since the warp beam rotates very slowly in a warp knitting machine, a reduction gear is installed in the drive connection between the warp beam and the electric motor in question, which adapts the different speeds of the electric motor and warp beam to one another. If an electric motor is used as the drive, which has a relatively high speed, the reduction gear can lead to self-locking in the gear, ie the gear is not able to transmit a torque in the reverse drive direction . Its self-locking prevents any rearward drive. In such a case, the coupling is arranged in the force transmission area between the warp beam and the self-locking point. This ensures that the tension on the warp threads exerted by knitting tools that continue to work in the event of a power failure can continue to rotate the warp beam without the self-locking effect, since the coupling separates the warp beam from the self-locking point in the event of its disengagement. It can happen, in particular when processing elastic warp threads, that when the knitting tools come to a standstill, these warp threads still exert such a pull on the warp beam that it initially rotates further, so that the warp threads finally sag without tension. Moments of inertia of the warp beam also play a role here. Such sagging of the warp threads is undesirable since this can result in confusion of the warp threads when the warp knitting machine is restarted. In order to eliminate this danger from the outset, a brake set in the power transmission area between the coupling and the warp beam can be arranged in such a way that the warp beam runs out while maintaining an admissible thread tension when the mains voltage is lost. Since the brake is only geared towards maintaining a minimum thread tension, very little braking action is required, so that the brake causes practically no additional energy consumption.

If, however, this energy consumption caused by the brake is undesirable, it can be eliminated by only allowing the brake to take effect when the clutch is disengaged.

The clutch can be advantageously used as a brake by giving it a spring tension acting in the direction of engagement such that the clutch acts as a brake when the mains voltage is lost. When the clutch is engaged under the effect of the mains voltage, the brake does not appear at all, since in this case the clutch causes the power transmission without slippage. If the network fails, only the spring tension acting in the direction of engagement remains in the clutch, which, however, is not able to keep the clutch in the engagement function. It presses the relevant clutch parts together only with a certain force, so that mutual rotation of the clutch parts is possible, but the clutch itself exerts a braking effect.

An exemplary embodiment of the invention is shown in the figures. Show it:

- Fig. 1 is a schematic representation of the reproduced

Warp knitting machine with a warp beam and separate electric motors for driving the main shaft and the warp beam, FIG. 2 shows a coupling with its drive connection leading to the warp beam, which is simultaneously designed as a brake.

The warp knitting machine shown in FIG. 1 consists of the machine frame 1 which is penetrated by the main shaft 2 for driving the knitting tools, not shown. The warp beam 3 with its axis 4 is mounted on the machine frame 1. Of course, the warp knitting machine can be equipped with several warp beams in a known manner. The warp threads 5 are drawn off from the warp beam 3 and fed to the knitting tools via the thread tensioning rocker 6 The main shaft 2 is driven via the two pulleys 7 and 8 and the toothed belt 9 which wraps around them. The pulley 8 is set in rotation by the electric motor 10, which thus forms the drive responsible for the rotation of the main shaft.

The warp beam 3 is driven via the two pulleys 12, 11, which are wrapped by the toothed belt 13. The pulley 12 sits on the shaft 14, which projects into a clutch, which is shown here in simplified form by the two clutch disks 15 and 16 opposite one another. When the two clutch disks 15 and 16 are pressed together, the clutch is in the engaged state. In Fig. 1 the two clutch disks 15 and 16 are shown separated from each other in order to show in this way that the clutch can assume a disengaged position in which the clutch then interrupts the drive. The clutch disc 16 is seated on the shaft 17 which carries the worm wheel 18. The worm wheel 18 engages in the worm 19, which sits on the axis of the electric motor 20, which thus forms the drive motor for the warp beam 3.

In normal operation, the speeds of the two electric motors 10 and 20 are coordinated with one another in a known manner by a control system in such a way that the speed of the warp beam 3 is adapted to the need for warp thread quantity determined by the work of the knitting tools. Both electric motors 10 and 20 are connected to the same network, so that they stop in the event of a network failure. Because of the masses connected to the main shaft 2, it then continues to run for a certain time, the knitting tools driven by it still pulling warp threads 5 off the warp beam 3. In ^{'Netztausfall} the motor 20 stops faster than the otor 10, in particular because no schnellge¬ turned large centrifugal masses are connected to it. So that the faster shutdown of the motor 20 compared to the shutdown of the motor 10 does not lead to a break of the warp threads 5, the clutch consisting of the clutch disks 15 ^"" and 16 is provided, which is also connected to the mains as an electrically actuatable clutch, whereby the clutch is designed so that it is engaged by the mains voltage, so it disengages in the event of a power failure. If the mains voltage were present, the two clutch disks 15 and 16 would be pressed against one another in such a way that they effect the torque transmission from shaft 17 to shaft 14. In the event of a power failure, the clutch disengages, so that the shaft _. 14, the pulleys 12 and 11 and the warp beam 3 can continue to rotate. The tension exerted on the warp threads 5 by the initially continuing knitting tools causes the warp beam 3 to rotate further, which acts to a certain extent as a backward-pointing drive, and the clutch disc 15 slowly runs out via the pulleys 11 and 12 and the toothed belt 13 takes, which rotates relative to the stationary clutch disc 16.

E _S is to be noted that structural details of such a coupling are shown in Fig. 2, will be discussed in more detail below.

By disengaging the clutch consisting of the clutch disks 15 and 16 in the event of a power failure, it is thus achieved that the knitting tools driven by the outgoing main shaft 2 can slowly pull warp threads 5 away from the warp beam 3 without the warp threads 5 being able to tear, since that of the warp threads 5 exerted on the warp beam 3 is readily able to bring about its slowly running rotation. The necessary Synchronization of the rotation of the main shaft 2 and of the warp beam 3 results automatically from the tension exerted on the warp threads and the resultant entrainment of the warp beam 3, which is not hindered during this outgoing rotation.

FIG. 2 shows an electrically actuable clutch which can take the place of the clutch formed by clutch disks 15 and 16 in FIG. 1. According to FIG. 2, the worm wheel 18 sits on the shaft 21 (which corresponds to the shaft 17 according to FIG. 1). The worm wheel 18 is non-rotatably connected to the shaft 21 by means of the wedge 22. The worm wheel 18 engages the worm ° 19, which, as shown in FIG. 1, is driven by the motor 20 shown there. On the shaft 21 there is also the clutch disc 16, which is connected to the shaft 21 in a rotationally and displaceably fixed manner by means of the wedge 23. The clutch disc 16 faces the axially displaceable clutch disc ⁰ 15, which is provided with the friction lining 24. When the two clutch disks 15 and 16 are pressed together sufficiently, the friction lining 24 causes the two clutch disks 15 and 16 to take each other along. The clutch disk 15 is mounted on the needles 5 25 with respect to the shaft 21, and the clutch disk 15 is movable relative to it give the shaft 21 so that the clutch disc 15 can be both axially displaced relative to the shaft 21 and rotated relative to the shaft 21. On the clutch disc 15, the belt pulley 12 is seated in a fixed connection with the clutch disc 15, so that when the clutch disc 15 rotates, the belt pulley 12 is taken along, which then takes the toothed belt 13 in the manner shown in FIG.

5 The electromagnet 26 with the magnet coil 27 is arranged in the region of the clutch disc 16, the electromagnet 26 being held in position by the support plate 28. There is an air gap 29 between the electromagnet 26 and the clutch disc 16, which ensures that the

Clutch disc 16 can rotate freely with respect to the electromagnet 26. This is a known construction of an electrically actuated clutch. When the magnetic coil 27 is energized (connection to the mains), the magnetic field generated by it causes the clutch disc 15 to be attracted to the clutch disc 16, as a result of which the clutch is engaged. This is / also a known process for electrically actuated clutches. In the event of a power failure, however, the clutch disc 15 is released (the effect of the compression spring 30 shown in FIG. 2 is initially left out), so that the clutch disc 15 no longer presses against the clutch disc 16, which disengages the clutch functionally. In this operating position, the shaft 21 can stop as quickly as desired, whereas the clutch disc 15 opposes the shaft

21 can rotate freely. 1 can then leave the pulley 12 and thus the clutch pulley 15 in slow rotation until the warp beam 3 has run out.

2 shows the compression spring 30, which is supported on one side against the ring 31 seated firmly on the shaft 21 and with its other side presses against the clutch disc 15. The compression spring 30 is set such that it presses the clutch disc 15 against the clutch disc 16 only with gentle pressure. This weak pressure of the compression spring 30 has the result that, when the clutch disk 16 is at a standstill and the clutch disk 15 continues to rotate, a weak friction occurs between the friction lining 24 on the clutch disk 16, which in this case acts as a brake. Due to this friction, the rotation of the clutch disc 15 is braked, so that a driven, in the event of a power failure to ^' next running warp beam 3 is braked accordingly and runs out. The pretension of the compression spring 30 is adjusted so that the warp threads 5 are not exposed to excessive tension due to the braking caused by them. If necessary, the ring -31 can be axially adjustable via the thread 32 to adjust the pretension of the compression spring 30. Depending on the axial position of the ring 31, a more or less strong pre-tensioning of the compression spring 30 and thus a more or less strong braking of an outgoing warp beam 3 is obtained. In this construction, the function of the clutch with the function of the brake is thus made use of the same components united. The brake thus prevents the continuing warp beam 3 from overtaking the continuing main shaft 2 to a certain extent in the event of a power failure.

In der.in ^'Fig. 2 illustrated embodiment, is located between the worm 19 and the shaft 21, such a large reduction before that by the worm 19 and the worm wheel 18 driving part formed a Selbst¬ inhibition has, in the case of standstill of the Schnek - Kenrades 19 prevents rotation of the shaft 21. The self-locking point lies in the area of the engagement of the worm wheel 18 in the worm 19. If, in the case of such self-locking, the drive-related separation of the warp beam 3 from the shaft 21 would not be possible, this would result in a power failure and further removal of warp threads 5 As a result, the warp beam 3 can no longer follow this train, so that the warp threads 5 would tear off. This tear is prevented by the separation of the drive by means of the clutch consisting of the clutch disks 15 and 16.

Claims

PATENT CLAIMS

1. Warp knitting machine in which the knitting tools and each warp beam are each driven by their own electric motor fed from a common network, characterized in that in the drive connection (19, 18, 17, 16, 15, 14, 12, 13, 11 , 4) between each warp beam (3) and the relevant electric motor (20) there is an electrically operable coupling (15, 16) ° which is connected to the mains and can be engaged by the mains voltage and disengages when it is removed.

2. Warp knitting machine with self-locking trained

^{'Kettbaumantrieben,} dadurchgekennzei ch¬ 0 net that the coupling (15,16) is arranged in the power transmission region between the warp beam (3) and Selbsthemmungs- point.

!. Warp knitting machine according to Claim 1 or 2, since ¬ 5 is characterized in that a brake (24, 30) set in the force transmission area between the coupling (15, 16) and warp beam (3) is such that the warp beam (3) runs out while maintaining a permissible thread tension.

4 _... Warp knitting machine according to claim 3, characterized in that the brake (24, 30) is effective when the clutch (15, 16) is disengaged.

5. Warp knitting machine according to claim 2 and 4, characterized in that the clutch (15, 16) is under such a spring tension acting in the direction of engagement (30) that the clutch (15, 16) as a brake (24 , 30) acts.