It is known how, in the weaving process, the incoming end of the weft yarn, which is commonly called the weft tail-end, is used during insertion of the weft and beating-up thereof by the reed, in order to keep the weft itself tensioned and thus ensure uniform and regular weaving free from slack wefts. Once this function has been performed, the weft tail-end is cut and therefore becomes a waste product which, as such, is pneumatically conveyed away via a removal duct into a storage container.

Said loose waste tail-end, further blown along by the conveying air inside the removal duct, may undergo actual separation of the individual fibres forming the same, thus increasing considerably its volume, in particular in the case of per se voluminous yarns. The total volume of the waste collecte is thus very considerable and this ends up by having a negative effect on the removal system since - in order to keep the removal system itself efficient and avoid the use of large-size containers which are bulky and awkward to handle - it is required to remove the material stored inside the container with a frequency which is correspondingly greater the smaller the volume of the container and the greater the number of weft tail-ends which are separated in fibres and hence swollen.

In addition, it must also be pointed out that, in most of the applications, the operation of emptying the weft waste container may be performed only when the loom is at a standstill, in order to prevent bothersome and damaging dispersal, into the environment, of weft tail-ends which are suspended in the air and continuously expelled by the removal system. In the known systems for pneumatic removal of the weft waste, in fact, the container forms an integral part of the removal duct circuit and is hermetically connected to it by means of seals so as to prevent the air flow conveying the weft tail-ends being introduced

directly into the environment, dispersing the loose tail-ends therein, instead of passing out through the special filtering grid provided in the container. Any dispersion of this type must in fact be eliminated as far as possible in order to prevent the weft tail-ends from being deposited on the warp yarns and becoming trapped in the newly formed fabric, causing a significant deterioration in the quality thereof.

One object of the present invention is therefore that of providing a pneumatic removal device for the weft waste which is free from the drawbacks described above and, in particular, a device in which the container for storing the weft waste is pneumatically separate from the removal circuit such that it is possible to perform the periodic emptying thereof, without interrupting operation of the loom.

Another object of the present invention is that of providing a removal system in which the volume of the weft waste is substantially smaller so as to allow the use of storage containers with smaller dimensions or, in case of unvaried dimensions, so as to require less frequent periodic emptying.

A further object of the present invention is also that of providing an removal system in which the weft waste is compacted to such a degree as to allow easy processing and handling thereof without drawbacks. In particular an object of the invention is that of preventing even the smallest dispersion of loose fibres into the environment during these operations.

All the objects indicated above are achieved, according to the present invention, by means of a device for compacting and discharging weft tail-end waste in a system for removal of said waste comprising a pneumatic conveying duct connected at one end to an inlet mouth for the weft tail-ends and at the other end to a storage container, characterized in that a zone of said conveying duct contains means for entangling said weft tail-ends and means for expelling the entangled weft tail-ends from an port, said means being suitable for regulating the expulsion of the entangled weft tail-ends into said storage container.

The invention, however, will now be better described in detail, with reference to preferred embodiments thereof, shown in the accompanying drawings, in which :

Fig. 1 is an axonometric, schematic and partially sectioned view of a first embodiment of the device for compacting and discharging the weft waste according to the present invention ; Figs. 2 and 3 are, respectively, two different partial cross-sectional views, on a larger scale, of the device according to Fig. 1 ; Fig. 4 is a view similar to that of Fig. 2 of a variation of the first embodiment of the device according to the present invention ; Fig. 5 is an axonometric, schematic and partially sectioned view of a second embodiment of the device according to the present invention ; Fig. 6 is an axonometric, schematic and partially sectioned view of a third embodiment of the device according to the present invention ; Fig. 7 is an axonometric, schematic and partially sectioned view of a fourth embodiment of the device according to the present invention ; and Fig. 8 is a view similar to that of Fig. 7 which illustrates a drive variation of the device according to the present invention, which can be used also in the embodiments shown in the preceding figures As shown in Fig. 1, the device for compacting and discharging the weft waste according to the present invention is arranged at the end of the duct 1 for pneumatically conveying the weft tail-ends which is normally present, in air looms, so as to connect an inlet mouth 2 for the weft tail-ends to a container for storage thereof (not shown). This device essentially consists of a tubular chamber 3 with a rectangular or cylindrical cross-section which is connected to said duct 1 via a stub pipe 4 projecting from a side wall thereof, the internal cavity of the stub pipe 4 being connected to the internal cavity of the chamber 3.

The angle formed by the stub pipe 4 with the chamber 3 and the internal ports of these two elements are designed so as to optimize, from the point of view of energy consumption, the operations of compacting and discharging of the weft waste, which will be described below. Preferably the angle formed between the axis of the stub pipe 4 and that of the chamber 3 is a right angle.

One of the ends of the chamber 3 is closed by an electric motor 5, the axis of rotation of which is coaxial with the chamber 3, whereas the opposite end is closed by valve means 9,10 and 11 which assume different configurations in the

various embodiments of the present invention. The chamber 3 is also provided with a side outlet opening 6 for the air conveying the weft tail-ends, which is protected by mesh or filter means which are suitable for retaining inside the chamber 3 the weft tail-ends supplied through the duct 1. Preferably, said opening 6 is formed in the wall of the chamber 3 opposite to that which contains the stub-pipe connection 4 and is arranged facing this connection so as to facilitate the outflow of the air conveying the weft tail-ends and prevent the formation of undesirable secondary outflows of the conveying air through the valve means 9,10 and 11.

Finally, the chamber 3 contains a spiral-shaped tool 7 which is rotationally driven by the motor 5 and which acts as a means for entangling the weft tail-ends supplie through the duct 1 and hence compacting them gradually so as to form a waste product 8 (only schematically shown in Fig. 1) which accumulates in the zone of the chamber 3 close to the abovementioned valve means 9,10 and 11.

Advantageous embodiments of the tool 7 may, for example, be that of a fixed or variable-pitch screw (Figs. 1 to 3), that of a wire wound in the form of a cylindrical or conical spiral (Fig. 4), that of a helix or other similar forms which may be chosen in each case depending on the type and the dimensions of the processed yarn. In any case the electric motor 5 must be sufficiently powerful to move without jamming up the overall quantity of waste which may be contained inside the chamber 3 in the compacted state and expel it through the valve means 9,10 and 1 1, also overcoming the resistance of the latter.

The purpose of the valve means located at the outlet end of the chamber 3 is in fact precisely that of preventing the weft tail-ends entangled by the tool 7 from being discharged too quickly, i. e. before the tool 7 has been able to complete its entangling function. In order to achieve this aim, said valve means may obviously assume different forms - which may also be selected depending on the type and the dimensions of the weft tail-ends - and, in the rest condition, are closed.

A first embodiment of the valve means is shown in Figs. 1 to 4 where said means consist of one or more circular elasto-plastic baffles 9 arranged in parallel planes perpendicular to the axis of the chamber 3 and any extension 3a thereof ;

said baffles are provided with a central hole having, in the case of the several baffles, decreasing dimensions in the direction towards the outlet of the chamber 3 and its extension 3a and moreover a plurality of radial incisions which determine - together with the nature of the material from which they are made - the overall rigidity thereof. A second embodiment of the valve means is shown in Fig. 5 where said means are in the form of a butterfly valve 10 which is kept in the closed position by its weight, by specific spring means or by both. The butterfly valve 10 may be provided in addition to the baffles 9 or, instead, as a single valve means, depending on the characteristics of the weft tail-ends. Finally a third embodiment of the valve means is shown in Fig. 6, where said means consist of an elastic membrane 11 with a generally conical shape and with an outlet hole which is sufficiently small, in the unexpanded position, to prevent the outflow of weft tail-ends which are loose, i. e. not entangled and compressed by the tool 7.

When the spiral-shaped tool 7 has a diameter which is less than the internal dimensions of the chamber 3, it may be possible to envisage advantageously one or more protuberances 12 projecting from the internal wall of the chamber 3 and integral therewith, as shown in Fig. 3, in order to prevent the entanglement of compacted weft tail-ends from being wound around the tool, reducing its thrusting ability towards the outlet valve means.

In the embodiment illustrated in Figs. 7 and 8, a constant suction air flow is maintained inside the pneumatic conveying duct 1 by means of an auxiliary aspirator A, connected to the side opening 6 of the chamber 3 via an extension 1 a of said duct. In this way inside the chamber 3 a constant suction of air through the valve means 9 is maintained and therefore these valve means may be reduced to a single baffle or may even be completely absent. In this embodiment, in fact, it is precisely the suction flow inside the ducts 1 and 1 a which keeps the weft tail-ends inside the chamber 3 until they have formed an entanglement of a size and consistency such that it is no longer affected by the suction air flow entering the chamber 3 and is therefore pushed outside of the latter by the action of the spiral-shaped tool 7.

Fig. 8 also shows the possibility of driving the spiral-shaped tool 7 using chain means which are in turn driven by a motor C already present on the loom

for other functions.

Finally the same Figs. 7 and 8 show the possibility of providing the device according to the present invention with a second conveying duct 13 for sucking in and compacting"wrong"wefts, i. e. wefts which were defective during insertion and which have been extracted from the shed and removed by a system for automatically repairing the weft, in the vicinity of which the intake mouth of the duct 13 is arranged.

The way of use of the compacting and discharge device according to the present invention is very simple and already clear from the preceding description.

The weft tail-ends which are in fact expelled from the weaving zone via the duct 1 are blocked inside the filter device 3 and, owing to the mechanical work supplied by the tool 7, are gradually compacted until they reach the desired consistency which can be easily controlled by suitably varying the resistance offered by the valve means 9,10 and 11. This operation is facilitated by the fact that, owing to the opposite positions of the connection 4 and the opening 6, the flow of air through the chamber 3 encounters the axis of the spiral-shaped tool 7, thus producing an immediate interference between the weft tail-ends drawn along by the air current and the tool itself. The weft waste which emerges from said valve means is therefore perfectly compacted and has a density such that it can be received, by means of gravity, inside a container which is open, and therefore pneumatically independent of the duct 1, without giving rise to any of the problems pointed out in the introductory part of the present description.

All of the objects of the present invention have therefore been fully achieved ; the compacted weft waste produced in accordance with the invention may in fact be handled with the greatest of ease and without any precautionary measures, in a manner entirely independent of operation of the loom. The operator in charge of the loom may therefore remove the waste even while the loom is in operation, without the risk of the waste returning into the weaving area and consequent soiling or deterioration of the fabric being formed. The compacted waste also has a volume which is much less than the volume of the uncompacted waste and cleaning of the respective containers may therefore be performed less frequently and may be easily automated and centralised for a

whole set of looms.

The present invention has been described with reference to certain specific embodiments thereof, but it is obvious that its ambit extends to include also the numerous variations within the obvious grasp of a person skilled in the art, so as to adapt the invention to the specific textile requirements encountered during practical application, provided that they fall within the scope of the present invention as defined in the accompanying claims.