EP0860531A2

EP0860531A2 - Machine for the cross coupling of webs of carded, not woven fibers, provided with rotary unloading belt

Info

Publication number: EP0860531A2
Application number: EP98102497A
Authority: EP
Inventors: Vani Olivo; Paolo Olivo
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-02-19
Filing date: 1998-02-13
Publication date: 1998-08-26
Also published as: IT1291420B1; ITPD970033A1; EP0860531A3

Abstract

The invention is a new machine for the coupling of webs, to be used for the production of not woven fabrics. The edge of a belt travels orthogonally to the motion of the collection belt, in such a way as to lay more layers of webs onto the first layer. The travel of the webs to be laid down is such as to guarantee a product with constant characteristics.

Description

The present invention concerns the sector of coupling devices for webs composed of not woven fibers, which may be either synthetic, vegetal, or animal fibers. In particular the invention concerns the devices for the cross coupling of layers of these webs.

The webs of not woven fibers are obtained by repeatedly carding masses of fibers of various nature until obtaining a layer of these fibers, all arranged in the same direction.

These webs are then coupled with other webs formed by fibers having cross or perpendicular directions.

Finally, the mass composed of more layers is sewn, glued, thermo-cohered or treated in another way, according to the final use for which it is destined.

At present, machines provided with several conveyor belts are used to couple webs whose fibers have cross or perpendicular directions, and in these machines one belt transports the web or webs, while other belts provide for laying the web to be positioned on the preceding web or webs.

The edge of the conveyor belt that lays down the web travels forward and backward between the edges of the belt that transports the web or webs on which the successive web is to be laid. The movement of the edge of the belt transporting the web to be laid down is compensated for by a corresponding, identical translation performed by a cylinder around which the belt itself slides.

Said machines present some drawbacks, the most important of which is the considerable air current caused by the conveyor belts that with their accelerated motion move the web to be laid down and disarrange its fibers, which results in inferior product quality.

Another drawback, typical of the machine models presently marketed, is the passage of the web among various conveyor belts that transport it from the card outlet to the unloading point; the passage among several conveyor belts disarranges the various fibers, which results in inferior product quality.

Other types of machines hold the web to be laid down between two coupled conveyor belts that successively pass on various fixed or travelling cylinders, until reaching the unloading point, where these coupled belts separate and release the web to be laid down.

The use of two coupled conveyor belts avoids the production of the air current that disarranges the web, but the various passages around too many cylinders weaken the fibers and modify their arrangement, which makes it impossible to guarantee the quality of the final product.

In order to eliminate all the above mentioned drawbacks, a new type of machine for the coupling of webs of carded, not woven fibers has been designed and implemented.

The fundamental principles that characterize the new machine are a simple, linear travel of the web to be laid down and the addition of a second conveyor belt, called counter-belt, suitable for maintaining the web to be laid down in the right position on its conveyor belt.

Beside the belt that collects the webs on which the successive web layers must be laid, the main parts of the machine comprise two conveyor belts, various fixed or travelling cylinders around which the two conveyor belts rotate, three trolleys sliding on rails, inextensible bands, anti-deviation devices, electric motors with rapid start and stop, several tighteners for the conveyor belts and the inextensible bands or chains. Other less important devices and/or complementary accessories will be mentioned and illustrated in the following detailed description.

An explanation of the meaning of the main terms used in the description is given here below:

collection belt: the belt that transports the web/webs on which the successive webs are laid;
conveyor belt: the belt that receives the web to be laid down from the card and passes it onto the unloading belt;
unloading belt: the counter-belt that is coupled with the conveyor belt for the segment along which the latter transports the web to be laid down, in such a way as to prevent the disarrangement of the web fibers.

The unloading belt and the conveyor belt advance direction is perpendicular to the collection belt.

The conveyor belt travel has the shape of a variable ring positioned above the collection belt.

In practice, the travel of the conveyor belt is made up of a first section from the point in which it receives the web from the card to the opposite edge of the collection belt, a descent section toward the collection belt, a return section toward the unloading point, a further return section and a last upward section.

The conveyor belt (upper part of the ring-shaped travel) receives the web from the card and covers a horizontal section and a successive downward section, passes around the roller provided for the coupling with the unloading belt, in such a way as to hold the web to be laid down, covers an horizontal section until reaching the unloading roller and there separates from the unloading belt, then continues its horizontal movement to reach a fixed roller, passes around the recovery roller and returns to the point in which it receives the web from the card.

The unloading belt is partially arranged around the conveyor belt and moves around some rollers, its path resembling a horizontal U. In particular, the unloading belt runs a forward and backward travel above the upper horizontal section of the conveyor belt, rotates around an auxiliary roller, goes down to the roller for the coupling with the conveyor belt, covers a horizontal section until reaching the unloading roller together with the conveyor belt, at the same time holding the web, and then returns to the upper horizontal section passing around other auxiliary rollers.

Some rollers guide the conveyor belt along its whole travel.

In particular, the roller around which the unloading belt couples with the conveyor belt, the roller in correspondence with which the conveyor belt separates from the unloading belt and lays down the web and a recovery roller placed in the return section - a section along which the conveyor belt moves after laying down the web - are not fixed, but each one of them is positioned on a trolley that slides parallelly to the surface of the collection belt.

The roller in correspondence with which the conveyor belt separates from the unloading belt and lays down the web hereinafter called unloading roller, is positioned on a trolley that indicatively slides from one edge to the other of the unloading belt, thus moving the point of separation from the unloading belt, and therefore the web release point, from one edge to the other of the web/webs on which the successive web is to be laid down.

The roller around which the conveyor belt couples with the unloading belt, hereinafter called coupling roller, is positioned on a trolley that slides from the edge opposite that in which the conveyor belt receives the web to approximately half the width of the collection belt.

The recovery roller is positioned on a trolley that slides indicatively from the edge near the point in which the conveyor belt receives the web to approximately half the width of the collection belt, in such a way as to maintain the travel of the conveyor belt constant.

To distribute a constant quantity of web on the collection belt, the unloading trolley travels at a given speed, while the recovery trolley and the coupling trolley travel at a speed that is equal to half the speed of the unloading trolley. In fact, since the coupling trolley advances in the same direction as the unloading trolley, but at half its speed, this ensures continuous and constant feeding of web to the unloading roller, that is, continuous and constant unloading of web.

To uniform and synchronize the movement of the trolleys that support the unloading, coupling and recovery rollers, these trolleys are connected with inextensible bands along a generically ring-shaped path. In particular, an inextensible belt drives both the recovery trolley and the coupling trolley, in such a way as to maintain the movement of the two trolleys constant and equal (though in opposite directions).

Tighteners are provided to guarantee that the tension of the conveyor belts and of the inextensible bands remains constant for the whole period of operation of the machine and during the various acceleration and deceleration phases of the trolleys.

Two anti-deviation devices, applied to the conveyor belt and the unloading belt, respectively, compensate for the lateral movement to which the belts may be subjected because of the imperfect parallelism of the various rollers or because of external agents.

The whole machine is controlled through an electric or electronic system or through an electronic computer.

One of the main characteristics of the new machine lies in the fact that the web is received directly by the belt that will unload it on the collection belt. The web supplied by the card covers a single, brief distance before being laid down.

To protect the web even from any deformation that may be due to the air currents generated by the motion, the new machine makes use of the upper unloading belt, which also serves to insulate the web from the environment during its transport.

The new machine, being provided with two conveyor belts only, has extremely simplified and therefore light moving parts. The inertial moments to be controlled during the stroke of the trolleys in the two directions are low. This ensures better response during reverse, better linearity of the trolley speed and reduced motive power applied.

Further, the use of a third trolley in the conveyor belt makes it possible to use two trolleys that travel in opposite directions to improve the balance of the machine.

Besides, the machine is provided with a closed-ring driving system, which ensures perfectly equal reversing times, on both travelling directions of the trolleys.

The reversing of the trolleys has always represented a weak point in the design of machines for coupling carded fibers. In fact, the homogeneity of the unloaded fiber mainly depends on the behaviour of the trolleys during their motion.

In the moment in which the unloading trolley, the coupling trolley and the recovery trolley stop during the reversing (forward and backward) the belts collect a greater quantity of fibers in the passage points of the circuits.

The greater quantity of material can be observed exactly at the ends of the unloading trolley stroke and at a certain distance from these points, towards the centre of the transported web.

The transversal profile of the laid-down fiber is irregular, thicker on the edges in correspondence with the points where more material is laid down, as described above.

The causes of this irregular thickness of the web may be the inertia of the trolley in the moment in which it reverses and the inertia of the motor that drives the trolley, since the latter has to slow down, stop and start again in the opposite direction.

In order to eliminate all the above mentioned drawbacks, the new machine drastically reduces the slowing down, stop and restart times of the unloading trolley, by employing a driving motor for each traveling direction of the trolley.

Practically, near the ends of the trolley stroke, while the trolley is reaching the end of stroke, the motor that will drive the trolley in the successive return stroke is started, too.

After the reversing, the motor that up to that moment had driven the trolley is stopped and let idle, while the motor that has just been started for the return stroke is kept in operation.

To avoid any tension due to the opposing action of the two motors on the band that connects the trolley with each motor, in the lapse of time in which both motors exert their tractive force, band tighteners are adopted, which move one or more cylinders or pulleys around which the band rotates.

In order to obtain the quick response of the trolley motion it is necessary that the band or bands that move the trolley and the trolley itself make up a closed circuit.

As already explained, the band or bands that transmit the motion to the unloading trolley, the coupling trolley and the recovery trolley make up a closed circuit, so that the tension on the band or bands remains constant for the whole distance covered by the trolleys. In particular, each band has one end fixed to the trolley, rotates around pulleys or cylinders, one of which is integral with the motor, and has the other end connected with the same trolley.

Two electric motors directly transmit the motion to the bands, each for every sliding direction of the unloading trolley.

The motors are preferably positioned on areas of the machine corresponding to the ends of the unloading trolley stroke.

Tighteners are provided to linearly translate some cylinders or pulleys around which the bands rotate.

These tighteners have the function to translate the cylinders or pulleys of a distance substantially equal to the band section driven by both motors when they are operated in opposite directions.

Said tighteners are two for each motor and are positioned one at the beginning (upper) and one at the end (lower), along the travel of the band with respect to the motor; that is, one tightener, hereinafter called upper tightener, positioned between the motor and the unloading trolley and one tightener, hereinafter called lower tightener, positioned between the motor and the recovery trolley. Their operation is combined and opposite; when the unloading trolley gets near the end of its stroke, and the return motor and the tighteners of the band driven by the unloading trolley are operated, said upper tightener moves the roller or pulley in the direction of the unloading trolley, while the lower tightener moves the opposite roller or pulley in the direction opposite to the movement of the unloading trolley and in the same direction as that of the recovery trolley.

Proximity sensors are positioned along the travel of the unloading trolley and detect its getting near the ends of its stroke.

The machine is completely operated and controlled through appropriate electric and/or electronic circuits and/or through a computer.

The operation of the several devices for the traverse reverse of the unloading trolley is briefly described here below.

It is assumed that the unloading trolley is moving toward one of the ends of its stroke.

One of the motors exerts its tractive force on the band that drives the unloading trolley; consequently the other band, sliding around the various rollers or pulleys drives the recovery trolley in the opposite direction.

The upper tightener positioned between the turned off motor and the unloading trolley holds the roller or pulley in the position that is furthest from the unloading trolley, that is, in the position in which the band covers a longer distance between the motor and said trolley.

The lower tightener positioned between the turned off motor and the recovery trolley holds the roller or pulley in the position that is nearest to the recovery trolley, that is, in the position in which the band covers a shorter distance between the motor and said trolley.

When the unloading trolley gets near the end of its stroke, the motor suitable for driving the unloading trolley in the opposite direction is operated.

As a consequence of this operation, the band positioned between the unloading trolley and the motor that drives the unloading trolley in its return stroke would be excessively stretched, while the band positioned between said motor and the recovery trolley would be slack. To avoid this, the appropriate upper and lower tighteners relevant to the motor that has just been started are operated and, traveling in the opposite direction, they reduce the distance covered by the band between said motor and the unloading trolley and at the same time they lengthen the distance between said motor and the recovery trolley.

As soon as the trolley reaches the end of its stroke the motor that has driven it up to that moment is stopped and the tighteners relevant to the motor that is now driving the trolley are shifted in the opposite direction and brought back to the previous positions.

The use of these devices in the two idling motors prevents the unloading trolley from being subjected to the restart of a possible single motor for the rotation in the opposite direction; the use of idling motors prevents the trolley from being subjected to the slowing down of the driving motor and the acceleration of the return motor; the use of the tighteners for the driving bands keeps the tension of the bands themselves constant and makes the unloading trolley move back much more quickly when it reverses; the return speed is equal to the sum of the motor rotation speed and the tightener travel speed.

The rollers can have considerable lengths and therefore can be bent, even with significant deflections that are dangerous for the operation of the machine.

To reduce the bending and therefore the deflection of the rollers, said rollers will have their rotary support shifted toward the center inside the roller itself, in such a way as to provide a "rotary fixed end" that halves such central lowering.

Each of these supports comprises a pin with considerable diameter fixed to the structure, whose end facing the roller is provided with a big cylinder or barrel. Two ball bearings to which the roller is applied are fixed onto the external surface of said cylinder or barrel.

The length and dimensions of the cylinder or barrel, and also the dimensions of the ball bearings are such as to prevent any relative bending between the roller ends and said cylinder or barrel.

The pin connecting said cylinder or barrel to the structure of the machine is fixed to the structure itself by means of a double spline on both sides of the wall to which it is constrained.

The machine is not provided with a mechanical shaft for the transmission of motion to the complicated right and left trolleys.

The complicated trolleys are driven by two motors, the synchronism of which is electronically controlled through a proper computerized system.

In this way the inertial loads and the number of moving mechanical parts are further reduced, which increases the performance levels and facilitates maintenance operations.

The machine described, both in its general concept and in the example of implementation, completely solves all the problems that were present in the past and that were reduced by means of particular mechanisms or expensive devices.

The following is just an example among many of the invention in question, illustrated in the attached drawings.

Figure 1 diagrammatically shows a vertical section of the machine, perpendicular to the advance direction of the web or webs on which the successive web is laid.

The web or webs on which the successive web is to be laid are transported by the collection belt (1).

The conveyor belt (2), which rotates around a series of rollers, slides above said collection belt (1) along a generically ring-shaped path. Said conveyor belt (2) receives the web from the card (3) and covers a horizontal section and a successive downward section, passes around the roller (7) provided for the coupling with the unloading belt (4), in such a way as to hold the web to be laid down, covers another horizontal section until reaching the unloading roller (5) and separates from the unloading belt (4), then continues its horizontal travel to reach a fixed roller, passes around the recovery roller (6) and returns to the point in which it receives the web from the card (3).

The unloading belt (4) runs a forward and backward travel above the upper horizontal section of the conveyor belt (2), rotates around an auxiliary roller, goes down to the roller (7) for the coupling with the conveyor belt, covers a horizontal section until reaching the unloading roller (5) together with the conveyor belt (2), at the same time holding the web, and then returns to the upper horizontal section passing around other auxiliary rollers.

The unloading roller (5), the recovery roller (6) and the coupling roller (7) are installed on trolleys (8, 9, 10) that slide on appropriate rails (11) parallelly to the surface of the collection belt.

The trolley (8) of the unloading roller (5) indicatively slides from one edge to the other of the collection belt (1), thus moving the point in which the web is released from one edge to the other of the web or webs on which the successive web is to be laid.

The trolley (10) of the coupling roller (7) slides from the edge opposite that in which the conveyor belt (2) receives the web, to approximately half the width of the collection belt (1).

The trolley (9) of the recovery roller (6) slides indicatively from the edge near the point in which the conveyor belt (2) receives the web, to approximately half the width of the collection belt (1), in such a way as to maintain the total distance covered by the conveyor belt (2) constant.

The unloading trolley (8) travels at a given speed, while the recovery trolley (9) and the coupling trolley (10) travel at a speed that is half the speed of the unloading trolley (8).

The trolleys (8, 9, 10) are connected with inextensible bands (12) along a generically ring-shaped path or, alternatively, as illustrated in Figure 4. In particular, an inextensible band (12) pulls either the recovery trolley (9) and the coupling trolley (10), in such a way as to maintain the movement of the two trolleys (9, 10) constant and equal (though in opposite directions).

Each inextensible band (12) is operated by two idling electric motors (16), each one of which pulls in a single direction and functions as freewheel in the reverse rotation. Tighteners (13, 14) ensure that the tension of the conveyor belts (2, 4) and of the inextensible bands (12) remains constant for the whole period of operation of the machine.

In particular, to prevent each band (12) connecting the trolleys (8, 9, 10) with each motor (16) from being subjected to tensions due to the opposing action of the two motors (16) in the lapse of time during which both motors exert their tractive force, each inextensible band (12) is provided with four tighteners (13) working in pairs, with opposite action, before and after each electric motor (16).

Two anti-deviation devices (15), applied to the conveyor belt (2) and to the unloading belt (4), respectively, compensate for the lateral movement to which the belts (2, 4) may be subjected because of the imperfect parallelism of the various rollers or because of external agents.

Proximity sensors (17) are positioned along the travel of the unloading trolley (8) and detect its getting near the ends of its stroke.

Fig. 2 shows three phases of the sliding of the belts and of the trolleys (8, 9, 10).

Fig. 3 shows the "fixed end" of each roller shaped in such a way as to reduce the deflections due to the operation.

Said "fixed end" is made up by a pin (18) with considerable diameter fixed to the structure (19), whose end facing the roller (R) is provided with a big cylinder or barrel (20). Two ball bearings (21) to which the roller is applied are fixed onto the external surface of said cylinder or barrel (20).

The length and dimensions of the cylinder or barrel (20), and also the dimensions of the ball bearings (21) are such as to prevent any relative bending between the ends of the roller (R) and said cylinder or barrel (20).

The above are the basic outlines of the invention, on the basis of which the technician will be able to provide for implementation; therefore, any change which may be necessary upon implementation is to be regarded as completely protected by the present invention.

With reference to the above description and to the attached drawings, the following claims are put forth.

Claims

Machine for the cross coupling of webs of carded, not woven fibers, provided with unloading belt rotating around a roller that performs an oscillating movement parallel to the plane of the web collection belt and orthogonal to the direction of the collection belt, characterized in that the web is conveyed to the unloading belt by a conveyor belt that runs a generically ring-shaped travel, couples with the unloading belt and remains coupled with it until reaching the unloading roller.
Machine for the cross coupling of webs according to claim 1, characterized in that the rollers around which the unloading belt and the conveyor belt couple with each other and then separate are positioned on trolleys that travel perpendicularly to the advance direction of the collection belt, and wherein the trolley of the unloading roller slides from one edge to the other of the collection belt, and wherein the trolley of the coupling roller slides from the edge opposite the edge on which the web is laid down to approximately half the width of the collection belt and then moves back, with a speed that is half the speed of the unloading roller.
Machine for the cross coupling of webs according to claims 1 and 2, characterized in that the recovery roller of the conveyor belt is positioned on a trolley that travels perpendicularly to the advance direction of the collection belt, and wherein said trolley slides from the edge on which the web is laid down to approximately half the width of the collection belt and then moves back, with a speed that is half the speed of the unloading roller.
Machine for the cross coupling of webs according to claims 1, 2, 3, characterized in that said sliding trolleys of the coupling roller and of the unloading roller are connected with each other by means of inextensible elements (such as bands, cables, etc.), in such a way as to ensure equal and uniform motion of the trolleys themselves.
Machine for the cross coupling of webs according to claims 1, 2, 3, 4, characterized in that the conveyor belt adheres to the unloading belt from the point in which the web is received to the point in which the web is laid down.
Machine for the cross coupling of webs according to the previous claims, characterized in that it is provided with tighteners either on the belts and on the inextensible bands or any other means for the connection of the trolleys, in such a way as to maintain the tension of belts and bands constant for the whole period of operation of the machine and in any moment of the trolley stroke.
Machine for the cross coupling of webs according to the previous claims, characterized in that it is provided with anti-deviation devices applied to the unloading belt and to the conveyor belt to compensate for the lateral movement of the belts.
Machine for the cross coupling of webs according to the previous claims, characterized in that it is provided with two motors equipped with freewheel for the counter-rotation that cause the translation with alternate motion of the trolley with the unloading roller by means of inextensible bands, and two motors equipped with freewheel for the counter-rotation that cause the translation of the coupling trolley and recovery trolley, and wherein each motor transmits motion to the bands, one for each sliding direction of the trolley, and wherein near the ends of the trolley stroke and in any case before the end of its stroke also the other motor is started, which will drive the trolley in its successive return stroke and will be stopped when the trolley has reached the end of its return stroke.
Machine for the cross coupling of webs according to the previous claims, characterized in that it is provided with tighteners of the driving bands, and precisely two tighteners for each motor, positioned one at the beginning and one at the end along the travel of the band with respect to the motor, said tighteners linearly moving some cylinders or pulleys around which the bands rotate, and wherein said tighteners move the cylinders or pulleys of a compensating section substantially equal to the length of the band pulled by both motors when they are operated simultaneously, but in opposite directions.
Machine for the cross coupling of webs, characterized in that each end constraint of the rollers consists of a pin fixed to the structure by means of a spline on one or both sides of the wall to which it is constrained, while the other end, facing the roller, is widened and wherein in correspondence with said widening two or more ball bearings to which the roller is applied are fixed.