It was proposed long ago, as is apparent for example from U.S. Pat. No. 4,467,594, to produce composite yarns by assembling two yarns textured by false twisting by means of a nozzle placed downstream of the false-twisting zone.
In order to produce such yarns, texturing machines of the type illustrated by the appended FIG. 1 are used, these being composed of a plurality of identical work positions which are arranged side by side on a support frame, preferably symmetrically with respect to a central axis YY and in a similar manner to the teachings of FR-A-2,459,847 and FR-A-2,619,127.
In such a machine, each work position includes a supply (1) of the yarn (2) to be treated, consisting of yarn supports mounted on a creel, this element not being shown in FIG. 1.
Each work position comprises, downstream of this supply, in the order of treatment:
a first forwarder (or pull-off) (3) of known type, for example of the strap-type, capstan-type or equivalent; PA1 guide elements (4) allowing the yarn to be transported into a first heater (5) preferably consisting of an open oven which is used for simultaneously treating two yarns in parallel; PA1 a cooling zone (6) for the yarn leaving the oven (5); PA1 a false-twisting spindle (7); PA1 a second pull-off (8) for the textured yarn leaving the false-twisting zone proper; PA1 a commingling nozzle (9) followed by a third pull-off (10), two yarns coming from two different positions being taken into the commingling nozzle (9) so as to form a composite yarn (11); PA1 a heat-treatment zone (12) for the composite yarn (11); and PA1 guide elements (13) followed by a fourth pull-off (14) delivering the composite yarn (11) to the wind-up means (15). PA1 a false-twist texturing zone comprising a first forwarder or pull-off, guide elements enabling the yarn to be transported into a heater, a cooling zone, a false-twisting spindle and a second pull-off for the textured yarn leaving the false-twisting zone proper; PA1 a zone enabling the two yarns textured at two adjacent positions to be assembled, said zone consisting of a commingling nozzle followed by a third pull-off downstream of which a second heat-treatment zone for the composite yarn is advantageously placed, on the output side of which zone the guide elements associated with a fourth pull-off enable the composite yarns to be delivered to the wind-up means. PA1 the yarn pull-off systems placed on each side of the texturing zone are mounted alternately on two parallel shafts which are controlled independently of each other; PA1 the heat-treatment ovens of the false-twisting zone are temperature-controlled by two systems independent of each other; PA1 the false-twisting spindles are advantageously motor-driven, enabling their speed to be varied depending on the nature of the yarns; PA1 the joining means for commingling the two yarns coming from two different texturing positions are placed, seen from the front, between said positions, enabling the two yarns to have an identical path before they are joined together.
Although such a type of apparatus enables composite yarns consisting of two individual yarns of the same kind, for example two polyester yarns together, two polyamide yarns, etc., to be easily produced, it is not, on the other hand, suitable when it is desired to produce composite yarns from individual yarns of a different nature, for example a composite yarn consisting of a polyamide yarn and of a yarn of another kind. This is because it is well known that, for each type of yarn, the texturing conditions are different, especially with regard to the temperature of the oven (5) which comes before the texturing spindle (7) and the amount of twist imparted by the spindle during the texturing operation.
Consequently, when it is desired to produce such yarns, one of the faces of the machine is generally set for treating one type of yarn, the other face a second type of yarn, and yarns are combined in the nozzle (9) by making a yarn treated on one face pass through the frame of the machine in order to transport it into the assembling zone, this assembling being carried out on the other face, thereby resulting in a tricky operation.
Now, a novel type of machine has been found, and it is this that forms the subject of the present invention, which allows such composite yarns, which may either be regular or, optionally, provide effects along their length, such as, for example, visible loops, slubs, etc., to be easily produced.
In a general manner, the machine according to the invention allowing production of a composite yarn by assembling two yarns textured by false twisting is composed, in a known manner, of a plurality of identical work positions which are arranged side by side on a support frame and supplied with yarns from wound packages mounted on a rack or creel, each position comprising, downstream of this supply, in the order of treatment: