Background Art As is well known this operation is called drawing-in and it is performed, outside the loom, by means of machines known as drawing-in machines. Therein, the different operative phases are carried out by means of multiple devices in mutual co-operation, which entails a considerable structural complexity of the machines.

Disclosure of Invention The main object of the present invention is to provide a method for the automatic drawing-in of the weaving elements of a loom-in particular of the heddles and of the reed-which can be implemented by an apparatus that is structurally simplified relative to those of the prior art.

A particular object of the invention is to provide a method and an apparatus for automatic drawing-in which allow to select and position heddles in a simple and effective manner.

A further object of the invention is to provide a method and an apparatus for automatic drawing-in which do not entail any risk of damaging the reed.

The aforesaid objects are achieved with the method and with the apparatus defined in the independent claims. Advantageous embodiments of the invention are defined in the dependent claims.

Brief Description of Drawings The features and advantages of the invention shall become more readily apparent from the detailed description that follows, made with reference to the accompanying drawings, which show an embodiment provided purely by way of non limiting example, in which: -Figure 1 is a perspective schematic view of an apparatus for automatic drawing-in

in accordance with the invention; -Figure 2 is a perspective view of the carriage bearing the operative organs ; -Figure 3 schematically shows a detail of the devices used for selecting and positioning asymmetrical heddles in a first operative phase; -Figures 4 and 5 are section views from the plane A of Figure 3 with the device for selecting the heddles in two additional operative phases; -Figure 6 is similar to Figure 3 but with the devices for selecting and positioning the heddles in a further operative phase; -Figure 7 is a section view from the plane B of Figure 6; -Figures 8a-8d and 8a'-8d'schematically show the phases of selecting two types of symmetrical heddles ; -Figures 9 through 11 show the device for drawing-in the reed in three different operativephases; -Figures 12 and 13 are partial frontal enlargements of two different types of heddles usable in an apparatus according to the invention.

Best Mode for Carrying Out the Invention With reference to Figures 1 and 2, an apparatus for automatically drawing-in warp threads through the weaving elements of a loom substantially comprises a support structure 1 whereto are fastened, in a removable manner, a system of rods 2,2' for supporting heddles 3, and a reed 4. More specifically, the rods 2,2' are arranged parallel at two different heights and the heddles 3 are hung to the upper rods 2 and hitched to the lower ones 2'. The heddles 3 thus form a plurality of parallel ranks and can slide with friction along said rods 2,2'.

The reed 4 is positioned at an intermediate height between the rods 2,2', with the teeth lying in a horizontal plane, without interfering with the heddles 3. For the support and the selection of blades, known means-not shown-can be provided.

The apparatus further comprises a motorise carriage 5, able to slide parallel to the rods 2,2' and to the reed 4 and bearing: -an assembly for the selection, according to a pre-set sequence, of the heddles 3 ; -an assembly for positioning each selected heddle in such a way as to allow its

drawing-in; -an assembly, comprising a horizontally movable hooked needle, for drawing the thread F from a beam S or from any feeding device and for driving it through the eye of the selected and positioned heddle; -an assembly for drawing-in the reed 4.

With reference to Figures 2 and 3, the carriage 5 comprises a front wall 50 provided with slits 51 for the passage of the rods 2 (partially shown in Figure 2) and of the heddles 3.

To said front wall 50 is connected the assembly for selecting the heddles 3 which comprises a pair of selector elements movable horizontally in a direction orthogonal to the rods 2. Said elements, in the illustrative embodiment are constituted by two metal ribbons 6,7 positioned horizontal and consecutive, controlled independently by means of two electric motors 60,70 which enable their bi-directional motion. Each ribbon 6,7 is in particular wound about a pulley 61,71 actuated by the respective motor 60,70. The free ends 62,72 of the ribbons 6,7 preferably present an acute angle profile for the purposes described below.

On the front wall 50 of the carriage 5, alternating with the slits 51, vertical metal platelets 52 are provided, each having a horizontal slit which serves as a guide for the selector ribbons 6,7. Only a part of said platelets is shown in Figures 1 and 2.

Underlying the assembly for the selection of the heddles, the positioning assembly is provided, which comprises an element able to cause a rotation of the median portion of each selected heddle in order to orient the plane of the eyelet 31 perpendicularly to the direction of motion of the needle 9. Said element, in the embodiment illustrated in Figures 3 and 6-7, is constituted by an additional metal ribbon 8, movable in an orthogonal direction to the rods 2 and bearing at the end a block 80 provided with an opening 81. Said opening 81 is oriented and shaped in such a way as to receive the selected heddle and cause its required rotation. Alternatively the opening 81 can be provided directly in the free terminal portion of the ribbon 8.

The heddle-rotator metal ribbon 8 is controlled by an electric motor 82 in a manner wholly similar to the two selector ribbons 6,7. Moreover, a plurality of holed metal platelets 54, similar to the platelets 52 guiding the selector ribbons, are provided with the

function of guiding the motion of the heddle-rotator metal ribbon 8. Said platelets 54 also co-operate in the rotation of the selected heddles, as shall be described better hereafter.

Below said holed platelets 54 is located the path of the needle 9, which is parallel to the ribbons 6,7,8 and is pependicular to that of the heddles 3. The needle 9, constituted by a thin metal ribbon shaped at its extremity in the form of a hook 91, is moved by an actuator, not shown herein, and is constrained and guided by a plurality of appendices 55 located below the platelets 54 guiding the heddle-rotator ribbons 8.

At the inferior part of the carriage 5, in correspondence with the stroke start area of the needle 9, is fastened the assembly for drawing and passing the thread F between the teeth 40 of the reed 4 (see Figures 9 through 11). As indicated above, the reed 4 is positioned with the teeth 40 lying in a horizontal plane and is connected to the loom 1 in a removable manner. In particular, said assembly comprises a rotating hook 100 for drawing the terminal portion of the thread F and a movable hooked knife 102 movable vertically for transferring the thread F between the teeth of the reed 4. Both the hook 100 and the knife 102 are moved by means of electric motors 101,103.

The electric motors employed are controlled electronically according to a predetermined program. The electronic devices used, being of a conventional type and available on the market, require no further specification.

The operation of the apparatus described above is substantially as follows.

The heddles are pre-arranged in packs 30,30', 30"along the rods 2,2'of the carriage 5 opposite to the front wall 50. The carriage 5 is then set in motion, along the support structure 1 and according to the reduction of the reed, towards the heddle packs, in such a way as to intercept in its path the heddles suspended to the rods 2,2'.

In the example illustrated in Figures 3 to 7 each pack 30,30', 30"is formed by mutually alternating so-called asymmetric (or duplex) heddles. For better comprehension, Figure 12 shows, from left to right, a first asymmetric heddle 3d conventionally defined as right, a second asymmetric heddle 3s conventionally defined as left and the two superposed heddles. Figure 13 shows two symmetric (or simplex) heddles 3d', 3s' separated and superposed.

In this phase, the selector ribbons 60,70 have the free ends 62,72 adjacent or slightly superposed, so as to constitute a barrier for the first heddle of each pack 30,30', 30" which, through the slits 51, comes in contact with the ribbons. A slight compression is exerted on the heddle packs 30,30', 30"which are in an elastic tensile state caused by said compression as well as by the friction of the heddles 3 on the support rods 2,2'and by the laminar shape of the heddles 3. Pushing means-not shown-of the heddle packs may also be provided.

With reference to Figure 3, in accordance with the set drawing-in pattern, the free ends 62,72 of the selector ribbons 6,7 are positioned in front of the selected pack 30. The first heddle 3a then comes in contact with the extremity 62 of a ribbon 6, whereas the subsequent heddle 3b is held both by the head profile of the first heddle 3a, and by the extremity 72 of the other selection ribbon 7. This results from the fact that the heddles are asymmetric and, in each pack, arranged in alternating fashion. The first heddle 3a is the one to be selected, whilst the second one 3b must be held, together with the successive ones, during the drawing of the first heddle 3a. Figure 3 shows also a previously selected heddle 3c, already involved in the drawing-in process.

In the subsequent phase, illustrated in Figure 4, the selection ribbon 6, which held the first heddle 3a, is retracted, thereby freeing the heddle 3a, which is thus projected forward and separates from the pack 30, due to the effect of the previously mentioned elastic forces. The second selection ribbon 7 continues to hold the second heddle 3b and all the subsequent heddles of the same pack 30. In the illustrated example the remaining packs 30', 30"are held by the first selection ribbon 6.

Due to the angled profile of the free extremities 62,72 of each metal ribbon 6,7, the sides 63,73 of each extremity located downstream in the direction of displacement of the selected heddle 3a constitute the active parts of two specular cams whose function is further to remove the heddle 3a from the pack 30. In fact, as shown in Figure 5, the second selection ribbon 7 in its motion to rejoin the first ribbon 6 causes, with the cam profile 73, the further advance of the selected heddle 3a.

The heddle 3a is then thrust into the opening 81 provided at the extremity of the heddle- rotator ribbon 8. In particular, the heddle is received in the opening 81 in

correspondence with its median portion, in an area proximate to the eyelet 32. As shown in Figures 6 and 7, by effect of the advancing motion of the heddle-rotator ribbon 8 and of the barrier interposed by the adjacent platelet 54, the heddle 3a, which is flexible, rotates its median part, placing the eyelet 32 on a substantially orthogonal plane to the direction of motion of the needle 9. Figure 7 also shows the upper part 300, not rotated, of the heddle 3a. At this point the needle 9 moves from its resting position, passes through the eyelet 32 of the heddle 3a, engages the thread F from the feeder device (beam S or other device) and returns to its original position, transporting the thread F through the eyelet 32 of the selected heddle 3a. The thread F thereby finds itself supported by the appendices 55 provided below the platelets 54.

Figures 8a-8d and 8a'-8d'schematically show the phases whereby two types of symmetrical (simplex) heddles are separated from the pack. In these cases, to hold the heddles following the selected one it is advantageous to shape the extremities 62', 72' of the selection ribbons 6', 7' in such a way that, while with one extremity the first heddle 3a'of the pack is held, with the other extremity the heddle 3a'is separated from the rest of the pack and simultaneously the subsequent heddles are held. This is obtained, for instance, by providing on the edge of one of the angled extremities (of the extremity 62' of the first selector ribbon 6'in the illustrated examples) a recess 64 able to serve as a check for the first heddle 3a'of the selected pack and to cause a misalignment of the vertices of the extremities 62', 72'. More specifically, in the case of laterally-milled heddles (Figs. 8a-8d), the separation of the selected heddle 3a'from the rest of the pack takes place by taking the extremity 62'of the first selector ribbon 6'in front of the selected pack with the first heddle 3a'in contact with the recess 64 (Fig. 8b).

Dimensioning the recess 64 so that it is substantially equal to the thickness of the heddles, the vertex of the extremity 72'of the second ribbon 7'can thus be inserted between the first heddle 3a'and the second heddle 3b'of the pack (Fig. 8c). In this way, while the second ribbon 7'holds the successive heddles, the selected heddle 3a, by effect of the aforementioned elastic compression, is removed from the rest of the pack (Fig. 8d). In the case of heddles lacking lateral milling, the phases for their separation from the pack are substantially the same, with the difference that the recess 64 is so

dimensioned as to cause the vertex of the second selector ribbon 7'to act on the thickness of the selected heddle 3a' (Fig. 8b'). In this way the heddle is deviated laterally (Fig. 8c') and, once it is released by the first selector ribbon 6', by elastic effect it moves away from the pack (Fig. 8d').

Figures 9 through 11 show the phases whereby the thread F is gripped by the rotating hook 100 and transferred to the hooked knife 102, which is then lowered to lay the thread F between the teeth 40 of the reed 4, with no risk of damage.

All the aforesaid operations are repeated cyclically until the programmed work has been completed by the machine.

The invention thus conceived can be subject to numerous modifications and variations, without thereby departing from the scope of the inventive concept. Moreover, all components can be replaced by technically equivalent elements.