The present invention relates to a bobbin forming device applicable to roving frames, of the type comprising a spindle for positioning the tube on which the bobbin will be formed, and a rotating flange, provided with a pressing finger, which rotates concentrically with respect to the tube, said rotating flange being responsible for twisting the rove to be wound onto the tube.

Roving frames generally have a plurality of bobbin forming devices which are responsible for forming bobbins with the roves provided by the drafting device of the roving frame.

These bobbin forming devices comprise a rotating flange which receives the rove on its upper part and delivers it to the tube positioned on the corresponding spindle by means of an oscillating pressing finger which leans tangentially on the outline of the forming bobbin.

The mentioned bobbins are connected by means of a mechanical transmission with a motor element responsible for providing them with a rotational movement.

In turn, the spindles on which the tubes are assembled are connected to a mechanical transmission that communicates the rotating movement to them from a motor.

Currently in roving frames, the flange and bobbin assembled on the corresponding spindle rotate in the same direction, the rotational speed of the tube being greater than the rotational speed of the flange, so that the rove is wound on the bobbin in a rotational direction opposite to the rotational direction of the tube and of the flange.

Given that during bobbin formation the rotational speed of the tube is greater than the rotational speed of the flange, it is the tube that draws or pulls the rove provided by the flange.

To carry out a correct rove delivery to the bobbin, the oscillating pressing finger of the flange is oriented towards the previous area of the flange with the rotational direction of said flange as a reference.

To achieve the winding of the rove onto the tube, the tube rotates at a greater speed than the flange, this difference in speed being the winding speed of the rove onto the tube.

In current roving frames, the production capacity can only be increased by increasing the rotational speed of the tube, which has technical limitations because from a certain speed, and especially when the forming bobbin reaches a certain diameter, the centrifugal force causes the expansion and deterioration of the rove which is being produced.

The technical problem that is posed is the development of a bobbin forming device that allows reducing the rotational speed of the tube, obtaining the same production, and subsequently reducing the negative effects of the centrifugal force of the obtained rove, or allowing a higher maximum assembly speed thus obtaining a higher production.

To solve the technical problem posed, a bobbin forming device applicable to roving frames, object of this invention, has been devised, which, like the ones previously described, comprises a spindle for positioning the tube on which the bobbin will be formed, and a rotating flange, provided with an oscillating pressing finger, that rotates concentrically around the tube, said rotating flange being responsible for twisting the rove to be wound onto the tube.

The device of this invention has the particularity that the rotational speed of the tube is less than the rotational speed of the flange and the oscillating pressing finger is oriented towards the rear area of the flange with the rotational direction of said flange as a reference.

The flange and the tube rotate in the same direction during bobbin formation, the flange being, due its greater speed, the one that winds the rove onto the bobbin, which rotates at a lower speed.

With this device, it is the flange which is responsible for pulling the provided thread onto the bobbin because the flange rotates at a greater speed than the tube.

Therefore, in comparison to current roving frames, this bobbin forming device allows obtaining the same production by rotating the tube at a lower speed, or increasing the roving frame production without the tube reaching rotational speeds in which the centrifugal force negatively affects the obtained rove bobbin quality.

The main advantages of this device are: an increase in production (higher winding speed with less spindle and tube revolutions), a lower consumption, better quality, a lower risk of rove breakage and a lower deterioration of the bobbin due to centrifugal forces.

Another feature of this device is that the tube carrying spindle on which the bobbin is formed can be assembled on the roving frame with the possibility of rotating freely, without a connection to any mechanical operation element, because the tension generated in the rove due to the greater rotational speed of the flange and the coincidence in the rotational directions of the flange and the winding of the rove onto the tube causes a suitable rotation of the tube and the carrying spindle of the same.

In this case, it has been contemplated that the device can incorporate a braking device responsible for acting on the tube to prevent its acceleration or excess rotation due to the centrifugal force itself. The possibility of assembling the spindle without mechanical traction produces other important advantages such as the possibility of dispensing with both mechanical and electronic communication with the provision of rove produced by drafting, because the spindle or bobbin speed is systematically adjusted according to the provision of rove produced by drafting.

Obviously, this device can also be used in those roving frames in which the spindle is mechanically connected by a suitable means of transmission with a drive motor.

To complement the description which is being carried out and with the aim of easily understanding the features of the invention, a set of drawings is herein enclosed in which, in an illustrating and non-limiting way, the following has been depicted:

• Figure 1 shows a diagrammatic elevational view of an embodiment of the device of the invention, in which the unassembled tube aligned with the spindle has been depicted, the rotational directions of the spindle and the flange having been referenced by arrows.
• Figure 2 corresponds to section A-A' of the device during bobbin formation, the oscillating pressing finger having been depicted slightly spaced from the forming bobbin, and not in tangential contact with it, to aid in the comprehension of the explanation which will be carried out below.

In the embodiment shown in Figure 1, the device of the invention can be observed, comprising a rotating flange (1) which receives a rotational movement from a mechanical transmission depicted in this embodiment by a toothed pulley (2) and the corresponding toothed belt (3). The device further comprises a spindle (4) for the assembly of a tube (5) on which the rove bobbin will be formed.

The flange has the particularity that the oscillating pressing finger (6) responsible for supplying the rove (7) with which the bobbin (8) will be formed on the tube (5) is oriented towards the rear area of the flange, with the rotational direction of the flange and the bobbin as a reference, which is a clockwise direction in this specific embodiment.

As can be observed in Figure 2, the flange (2) carrying the oscillating pressing finger (6) and the tube (5) associated to the corresponding spindle (4) rotate in the same direction, the rotational speed (St) of the tube (5) being lower than the rotational speed (Sf) of the flange.

The speed of the flange (Sf), which is greater than the speed of the tube (St), causes a tension in the rove (7) supplied to the bobbin (8), the rove (7) being wound onto the bobbin in the same rotational direction as the flange (1) and the tube (5).

The tension produced in the rove (7) due to the difference in speeds between the flange and the tube may be enough in certain cases and depending on the type and material of the rove, to cause the rotation of the tube (5) and of the spindle (4) without said spindle (4) being driven by a motor.

In these cases, the spindle (4) can be assembled with the possibility of rotating freely on the roving frame and can be provided with a braking device which is not depicted and can be of any type, to prevent the spindle (4) and subsequently the forming bobbin (8) from rotating uncontrollably or at a speed greater than the one desired, due to the force of inertia.

Having sufficiently described the nature of the invention as well as a preferred embodiment, it is stated for the record that the materials, shape, size and arrangement of the described elements may be modified, as long as it does not entail altering the essential features of the invention which are claimed below.