EP0239514B1 - Rotary dobby for looms - Google Patents

Description

The present invention relates to mechanics for the formation of the crowd on the weaving machines and it relates more particularly to the dobbies of the rotary type, that is to say in which the control of the alternating vertical displacement of each heald frame is provided by means of an oscillating rod, one end of which is coupled to said frame while the opposite end, cut out from an opening, is engaged on an actuating eccentric.

By EP-A-0 036 830 in the name of the Applicant, rotary dobbies are known in which the eccentric, mounted idly on a shaft driven in a rotational movement with stop every 180 _° , is secured laterally to an overflowing plate forming a support for a coupling member intended to angularly link the shaft to the eccentric at the right time in order to operate the displacement of the connecting rod and of the frame coupled to the latter. This coupling member, thus placed outside the eccentric, is in fact constituted by an articulated hook which is subjected, against elastic return means, to the action of one or the 'other of two pivoting selector levers actuated by the reading device of the dobby, according to the program incorporated in said device. Each of the two opposite ends of the hook has a spout capable of cooperating with one or the other of two notches formed in a drive disc angularly secured to the jerky rotation shaft.

It is understood that when one of the hooks spouts is engaged by the elastic return means inside one of the notches of the drive disc, the eccentric is angularly linked to the shaft and operates the actuation of the connecting rod. On the contrary, when one of the pivoting selector levers comes to bear against the hook, there is no longer coupling and the eccentric is therefore not displaced by the shaft, so that the connecting rod is not itself not even ordered; as at this position the other hook spout is engaged in a notch made in an annular boss of the connecting rod, the latter is angularly linked to the eccentric through the hook and is consequently immobilized, thereby avoiding any displacement parasite of the connecting rod under the effect of the weight of the corresponding heald frame.

The object of the present invention is to simplify the construction of the rotary dobbies according to the aforementioned French patent, without adversely affecting the reliability of the operation.

According to the invention, each of the articulated hooks is profiled on its outer edge in order to cooperate, when actuated with uncoupling, with one or the other of two retaining latches mounted at two points diametrically opposite with respect to the dobby tree.

• Fig. 1 est une coupe transversale d'une ratière rotative suivant l'invention, montrant l'agencement de l'un des ensembles de celle-ci destinés à la commande des cadres de lisses.
• Fig. 2 est une coupe axiale partielle de l'un de ces ensembles.
• Fig. 3 et 4 sont des vues de détails illustrant le fonctionnement du crochet basculant d'accouplement.
• Fig. 5 est une coupe transversale analogue à celle de fig. 1, mais correspondant à une variante de mise en oeuvre de l'invention.

The appended drawing, given by way of example, will allow a better understanding of the invention, the characteristics which it presents and the advantages which it is capable of providing:

• Fig. 1 is a cross section of a rotary dobby according to the invention, showing the arrangement of one of the assemblies thereof intended for the control of heald frames.
• Fig. 2 is a partial axial section of one of these assemblies.
• Fig. 3 and 4 are detail views illustrating the operation of the tilting coupling hook.
• Fig. 5 is a cross section similar to that of FIG. 1, but corresponding to a variant implementation of the invention.

In fig. 1, reference 1 designates the frame of the dobby, which supports the main shaft 2 animated by the jerky rotation movement, which shaft is intended to control a series of oscillating connecting rods 3 each of which is coupled by a lever 4 to one of the heald frames 5 of the weaving machine associated with the dobby under consideration.

As more particularly shown in fig. 2, each of the connecting rods 3 is cut, opposite its coupling point with its lever 4, an opening 3a which is engaged, with the interposition of a bearing 6, on the cylindrical periphery of an eccentric d 'actuation 7; the latter is mounted idly on the shaft 2 by means of a bearing 8. Each connecting rod 3 is associated with a drive disc 9 angularly secured to the shaft 2 and it will be observed that the periphery of this disc 9 is cut from two notches 9a, diametrically opposite one another. These two notches 9a are intended to cooperate with an articulated coupling hook 10 mounted on a small axis 11 carried by an overhanging plate 7a, laterally secured to the eccentric 7.

Fig. 3 and 4 clearly show the profile of the hook 10 which has, on either side of its articulation axis 11, a selection arm 10 'and a coupling arm 10 ". The edge of this arm 10" which is turned towards the disc 9 has a projecting spout 10a, which is clean under the effect of elastic return means constituted by a spring 12 interposed between the plate 7a and the end of the arm 10 "of said hook, to be worn permanently against the free edge of the disc 9 and to engage, during each stop of the shaft 2, inside one or the other of the two notches 9a.

The hook 10 is controlled, against the spring 12, by the end of two selector levers 13 (fig. 1) pivotally carried by two fixed axes 14 oriented parallel to the shaft 2. These pivoting levers 13 are coupled one to the other by a link 15 and one of them (the one on the right in fig. 1) has an extension on which two rods 16 are articulated which are moved transversely to their axis by two needles 17 controlled axially by a program 18 reading device with electronic or mechanical operation. In the usual way, the transverse displacement of the rods 16 under the effect of the needles 17 allows, according to the program incorporated in the device 18, to the said rods either to cooperate with two pushers 19 with reciprocating movement thereby ensuring the actuation of the two pivoting levers 13, or to escape the action of said pushers 19 while remaining stationary.

It will be observed that a spring 20, interposed between one of the levers 13 and the frame 1, tends to spring back permanently in the direction of the shaft 2 the end of the lever 13 with which it is associated, and on the contrary to maintain the end of the opposite lever 13 spaced from said shaft, so that the action of this spring 20 is exerted in an antagonistic manner with respect to that of the pushers 19. A fixed stop 21 limits the tilting of the levers 13 under the effect of the spring 20.

The operation of the dobby described above is easily understood.

If, during the stopping of the shaft 2, the selector lever 13 which is then placed at the level of the hook 10 receives no action from the reading device 18 (case of fig. 3), the spring 12 associated with said hook 10 elastically engages the spout 10a thereof in the notch 9a of the drive disc which is then placed opposite; there is therefore coupling of the shaft 2 and the eccentric 7 through the hook 10 and the disc 9, so that the connecting rod 3 is controlled.

If, on the contrary, during the stop, one of the two selector levers 13 exerts an action on the hook 10 which is then pushed back until its arm 10 'comes into contact with the disc 9, in the manner illustrated in fig. 4, the spout 10a is released from the notch 9-a and there is no coupling; the eccentric 7 cannot then actuate the connecting rod 3.

However, it is essential to ensure at this time the positive immobilization of the rod-eccentric assembly and it is for this purpose that provision has been made in the outer edge of the arm 10 "of the hook 10 and beyond the finger 10a, a notch 10b which is intended to cooperate with the terminal spout 22a of one or the other of two locks 22. As shown in Fig. 1, these two locks 22, oriented opposite l 'from one another, are mounted on longitudinal supports 23 fixed to the frame 1 so as to be diametrically opposite one another with respect to the shaft 2.

It is understood that when one of the selector levers 13 actuates the hook 10 in the manner illustrated in FIG. 4, the arm 10 "of the latter is projected outwards, so that the notch 10b naturally comes to hook against the spout 22a of the lock in question; the latter thus ensures, through the hook 10, the angular immobilization of the eccentric 7 and of the connecting rod 3. As soon as the action of the selector lever 13 on the hook 10 ceases, the spring 12 associated with the latter operates the disengagement of the notch 10b from the beak 22a of latch 22.

In normal operation, the latches 22 remain perfectly stationary since it is the articulated hook 10 which is hooked by its notch 10b. However, with a view to constituting a safety device capable of operating automatically, each of these latches 22 is pivotally mounted on its support 23 and receives the action of a spring 24 which tends to keep it applied against a fixed stop 25. Under these conditions, if following a malfunction the spout 10a of the hook 10 were to remain partially engaged in one of the notches 9a of the disc 9 while the corresponding lock 22 would still ensure the retention of said hook, consequently of the frustoconical profile imparted for this purpose to the spout 22a and to the notch 10b, the force exerted by the hook on the bolt would cause the latter to tilt against its spring 24 and the total release of said hook.

It will be observed that the angular immobilization of the connecting rod 3 as ensured in accordance with the invention has very great simplicity while proving to be perfectly effective. The plate 7a of the eccentric 7 and the hook 10 itself can be constituted by flat parts having no camber or bending. It will be noted that the coupling and immobilization functions are grouped together in the same arm 10 "from the single hook 10, which makes it possible to obtain very high precision. In addition, and the point deserves to be underlined, there n 'There is action on the hook 10 that during the angular immobilization of the rod 3, which limits wear to a considerable extent.

It should be noted that an identical result would be obtained by mounting the locks 22, no longer on common supports 23 integral with the fixed frame 1 of the dobby, but on individual supports 26 provided on each of the connecting rods 3 themselves, the way illustrated in fig. 5. The angular immobilization of each connecting rod 3 is then ensured by connecting the latter to its actuating eccentric 7, as in the prior EP-A-0 036 830 mentioned at the beginning of the present document.

Claims (2)

1. Dobby of the rotary type for weaving machines, of the type in which each of the oscillating rods 3 coupled to the heddle frames 5 is mounted on an eccentric 7 for actuation which rotates freely on a shaft 2 with jerky rotation but which may be angularly connected thereto through, on the one hand, a drive disc 9 fast with said shaft and, on the other hand, an articulated hook 10 comprising a selection arm 10' and a drive arm 10" provided on either side of its pivot axis 11, which hook, borne by a plate 7a of the eccentric 7, is placed under the control of one or the other of two pivoting selector levers 13 associated with a reading device 18 with a view to acting against elastic return means 12 tending to engage the nose 10a of the coupling arm 10" in one or the other of two notches 9a in the disc 9, the rod 3 being angularly immobilized when the lever 13 in question acts on the hook (10) to disconnect it from said disc 9, characterized in that the coupling arm 10" of the articulated hook 10 comprises, substantially opposite the drive nose (10a), a profile adapted to cooperate, at the moment of withdrawal of this nose (10a), with one or the other of two outer retaining locks 22 which consequently ensure angular immobilization of the eccentric 7 and of the rod 3 in question.

2. Dobby according to Claim 1, characterized in that the outer edge of the coupling arm 10" of the hook 10 has a notch 10b cut out therein, of truncated section, whilst each lock 22, provided with a hooking nose 22a of the same section, is mobile against elastic return means 24 so as to constitute a safety system ensuring automatic displacement of the lock and release of the hook in the event, further to an incomplete pivoting, of said hook 10 still being angularly connected to the drive disc 9.

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