Patent Application
20080295293
This application claims priority from German Patent Application No. 10 2007 026 158.8 dated Jun. 4, 2007, the entire disclosure of which is incorporated herein by reference.
The invention relates to an apparatus on a spinning works preparation machine, e.g. a draw frame, flat card, combing machine or the like, in particular a double-head draw frame.
In the textile industry, draw frames are often used to even out the card sliver. A very simple and cost-effective variant is a machine having two drafting systems working in parallel, what is known as a double-head draw frame. In these machines, which inter alia have two feed creels and two can coilers or can changers, the working elements of the two sides are driven in each case by a common drive. The result of this, however, is that in the event of a fault on one of the two sides, both sides have to be shut down. This in turn means that although the looms are relatively cost-effective, the achievable efficiency compared with other looms is very low.
A double-head draw frame is known from DE-A-31 33 436, in which a motor drives a variable speed gear mechanism and a releasable, electrically operable coupling is arranged between the driving belt pulley of the variable speed gear mechanism and the main shaft. In the event of a fault, the motor is switched off, the coupling is activated and a brake is engaged. Through the coupling, the brake needs to decelerate only the main shaft and elements driven thereby, and not the motor with its relatively large inertia. In this apparatus, the two heads of the draw frame are mechanically coupled rigidly to one another. They may be isolated from the drive motor by means of the coupling, but only both at the same time. In the event of a fault in one of the draw frame heads, there is no provision in DE-A-31 33 436, and it is also impossible with the known device, to allow the other draw frame head to continue production. The effectiveness and efficiency is in that way limited in the known apparatus. In addition, only one coupling is provided.
It is an aim of the invention to produce an apparatus of the kind described initially, which avoids or mitigates the said disadvantages, which is in particular of simple construction and inexpensive, and permits the effectiveness and efficiency to be considerably increased.
The invention provides an apparatus on a spinning preparation machine, having:
a first driven drafting system for drafting at least one fibre sliver with drafting rollers, and having at least one force-transmitting element for driving the drafting rollers of the first drafting system;
a second driven drafting system for drafting at least one fibre sliver with drafting rollers and having at least one force-transmitting element for driving the drafting rollers of the second drafting system; and at least one drive motor;
wherein a force-transmitting element for the first drafting system and a force-transmitting element for the second drafting system are connected via a respective coupling to a said drive motor and the rotational speed of the motor can be reduced for engagement and disengagement of the couplings.
The features according to the invention enable the efficiency to be quite considerably increased in a simple manner. Particular advantages are that in a double-head draw frame a respective common variable-speed drive can be used for the individual functions and the drive trains of the left-hand and right-hand sides are connected to the motor via two controllable couplings. In this way it is possible, if required, to shut down (disengage) one side of the machine and yet to continue production with the other side. To achieve a relatively smooth transition upon engagement and disengagement, the rotational speed of the motor can be automatically reduced for this procedure and subsequently accelerated again.
The invention can produce the following further advantages:
The delivery speed and the main draft can be infinitely variable without the reversal of belts or the like.
The option of being able, if required, to separate the drive chains (couplings), enables the efficiency and the productivity of the machine to be considerably increased and these properties to approach those of a single-head draw frame.
If activation of the couplings is pulsed, it is possible to produce a smooth speed transition, above all during re-engagement.
Because the rotational speed of the drive motor can be reduced at every engagement and disengagement process, a smooth speed transition is possible.
The apparatus according to the invention may be used for virtually all drive configurations. This applies to double-head draw frames with just a single motor, to those with a main and a servomotor or to draw frames with a main motor and a gear mechanism (to produce the draft). Moreover, it may be used in the case of motors with and without speed adjustment. In addition, combinations are possible, e.g. variable-speed main motor and variable-speed servomotor. The invention may also be used for the drive of the can turntable.
Advantageously, in the event of a problem in one of the two working heads, the corresponding drive chains can be isolated from the motors by means of the controllable couplings and, after correcting the problem, can be brought together again and the machine side not affected continues production during the period in which the problem exists. Preferably, the rotational speeds of the motors can be reduced before and during an engagement and disengagement process. In some embodiments, the rotational speeds of the motors can be reduced to zero before and during an engagement and disengagement process.
In certain embodiments, the couplings are activatable in pulsed manner for engagement and disengagement. Advantageously, the pulse and/or pause times for activation of the couplings are variable. Advantageously, the pulse and/or pause times for activation of the couplings are variable in dependence on the reduced rotational speeds of the motors.
In certain embodiments, the couplings used operate electromagnetically. In certain other embodiments, the couplings used operate pneumatically. In yet further embodiments, the couplings used operate hydraulically.
Any suitable motors can be used for the drives, for example, speed-controlled motors, or variable speed motors.
Advantageously, in the case of a double-head draw frame, a respective common variable speed drive motor is used for the individual functions.
Advantageously, the drive chains of the two drafting systems (sides) are connected to the drive motor via at least two controllable couplings.
Advantageously, the or each drive motor has two outputs. Preferably, one output is used to drive the one drafting system and the other output is used to drive the other drafting system.
The invention also provides an apparatus on a spinning preparation machine, e.g. a draw frame, flat card, combing machine or the like, in particular a double-head draw frame, having at least two driven drafting systems for drafting in each case at least one fibre sliver with drafting rollers forming drafting roller pairs, having force-transmitting means for driving the drafting rollers and at least one drive motor, an electrically operable coupling being present between a drive motor and a drive shaft, wherein the particular drive chains are connected via a respective controllable coupling to the motor and the rotational speed of the motor can be reduced for the engagement and disengagement process.
a to 3e are graphical examples for the course of the rotational speed of the motor and the rotational speed of the left-hand and right-hand drive chain when a fault occurs,
a to 5c are graphical illustrations of a pulsed activation of the coupling;
With reference to
A driving pulley 4 is mounted non-rotatably on the shaft extension 2a of the motor 2 (main motor), and is connected by means of a continuously revolving toothed belt 5 to the driven pulley 6, which is arranged non-rotatably on the main shaft 7. The main shaft 7 drives the two bottom rolls Ia and Ib coaxially. An electromagnetic coupling 8 is arranged between the pulley 6 and the bottom roll Ia and an electromagnetic coupling 9 is arranged between the pulley and the bottom roll Ib.
The motor 3 (variable-speed motor) has a rotating drive shaft, which forms the two shaft extensions 3a, 3b (shaft ends) projecting beyond the two end faces. Driving pulleys 10 and 11 are mounted non-rotatably on the shaft extensions 3a and 3b respectively. An electromagnetic coupling 12 is arranged between the motor 3 and the pulley 10 and an electromagnetic coupling 13 is arranged between the motor 3 and the pulley 11. The driving pulley 10 is connected by means of a continuously revolving toothed belt 14 to the driven pulleys 15 and 16 for the bottom rolls IIIa and IIa respectively. The driving pulley 11 is connected by means of a continuously revolving toothed belt 17 to the driven pulleys 18 and 19 for the bottom rolls IIIb and IIb respectively. The letter A denotes the direction of working for the two drafting systems Ia and Ib.
The drive chains—in the example of
Thus, in a double-head draw frame, in each case a common variable-speed drive motor 3 is used for the individual functions. The drive chains of the left-hand and right-hand side (i.e. for the two drawing heads) are each connected via two controllable couplings 8 and 12, and 9 and 13, respectively, to the motors 2 and 3. This enables one side of the machine to be shut down (disengaged), if required, yet production to be continued with the other side.
A further driving pulley 42 is non-rotatably arranged on the main shaft 7 and is connected by means of a continuously revolving toothed belt 43 to the driven pulley 44 for the take-off roll 45a, which co-operates with the take-off roll 46a. Yet a further driving pulley 47 is non-rotatably arranged on the main shaft 7 and,—in a corresponding manner as explained for the take-off rolls 45a, 46a—drives the co-operating take-off rolls 45b, 46b via pulleys 47, 49 and a toothed belt 48.
In the illustrative embodiment of
In
As required, one side of the machine, i.e. one drawing head 1a or 1b—is shut down (disengaged), and production is continued with the other side of the machine, which is not shut down (engaged). In order to achieve a relatively smooth transition upon engagement and disengagement, the rotational speed of the motor is automatically reduced for this operation and then accelerated again (see
The concept of reducing the rotational speed of the drive motor specifically for the engagement and disengagement process is based on the fact that a relatively smooth and predetermined speed transition can be achieved in this way. This applies especially to re-engagement. An example will explain this process in more detail.
The machine produces sliver at a speed of 600 m/min. A drawing head 1a or 1b has a fault. The speed is specifically reduced to 50 m/min, e.g. after a predetermined ramp. The drive of the faulty drawing head is disengaged and runs down to a standstill. This procedure is reduced to a reasonable minimum by the preceding and specific reduction in rotational speed. The delivery speed is again increased to 600 m/min. After correcting the fault, this is signalled (using a key), e.g. by the operator. The speed is reduced to 50 m/min, the coupling engages and the speed is again increased to 500 m/min (see
If the re-engagement process were to take place at full delivery speed, then the speed of the disengaged drawing head would accelerate more or less abruptly from 0 to 600 m/min. This would certainly result in tearing of the incoming or exiting sliver. The advantage of this measure is to produce a specific speed transition that is as smooth as possible. This advantage is achieved even more effectively by a pulsed activation of the coupling (see
If just one coupling were to be to be used, then an aim might have been to increase the productivity or efficiency of a double-head draw frame, but a simultaneous speed reduction would not have come into consideration. With just one coupling, only one drawing head can be isolated from the drive branch. This means that in the event of a fault in the drawing head, which cannot be isolated on the drive side, the whole machine must nevertheless be shut down and this in turn has a negative effect on the efficiency.
In the graphs of
With reference to
The reference numeral 55 denotes a display device that is connected to the control system 50.
In
A drafting system inlet 56a is located upstream of the drafting system 1a and a drafting system outlet 57a is located downstream of the drafting system 1a. The fibre slivers 58a, coming from cans (not shown) or from canless fibre sliver packages, enter a sliver guide 59a, are drawn off by take-off rollers 60a, 61a and are transported onwards in direction A. The drafting system 1a is designed as a 4-over-3 drafting system, that is, it consists of three bottom rolls Ia, IIa, IIIa (Ia being the bottom delivery roll, IIa being the middle bottom roll and IIIa being the bottom feed roll) and four top rolls 62a, 63a, 64a, 65a. Diameters chosen for the bottom delivery rolls Ia may be, for example, 40 mm, for the middle bottom rolls IIa, 35 mm and for the bottom feed roll IIIa, 35 mm. The bottom rolls Ia, IIa and IIIa have a helical grooving. Drafting of the fibre sliver comprising several fibre slivers 58a takes place in the drafting system 1a. The draft is made up of the preliminary draft and the main draft. The roll pairs 65a/IIIa and 64a/IIa form the preliminary draft zone and the roll pairs 64a/IIa and 62a,63a/Ia form the main draft zone. The drawn fibre slivers reach a web guide 66a at the drafting system outlet 57a and are drawn by means of the take-off rolls 45a, 46a through a sliver funnel 67a, in which they are condensed to a fibre sliver 68a, which is subsequently deposited (not illustrated) in cans or as a canless sliver package. The letter A denotes the working direction. The exit speed of the fibre sliver 68a is for example, 1200 m/min and more. The direction of rotation of the rolls is indicated by curved arrows.
The apparatus of the invention can be applied to virtually all drive configurations. This applies to double-head draw frames with just a single motor, to those with a main motor and a servomotor or to draw frames with a main motor and a variable speed gear mechanism (to produce the draft). Moreover, it can be used in the case of motors with and without rotational speed adjustment. In addition, combinations are possible, for example, variable-speed main motor and variable speed servomotor. The invention can also be used for the drive of the can turntable.
Although the foregoing invention has been described in detail by way of illustration and example for purposes of understanding, it will be obvious that changes and modifications may be practised within the scope of the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2007 026 158.8 | Jun 2007 | DE | national |
