EP0078752B2 - Dobby of the rotation type - Google Patents

Description

The present invention relates to the dobbies of the rotary type for training the crowd on the looms.

It is known that in the rotary dobbies the movement of lifting and lowering of the heald frames is ensured by oscillating parts constituted either by rod-lever assemblies or by roller-bearing levers, said oscillating parts being controlled by elements actuation (in the form of eccentrics in the first case, cams in the second) mounted on the main shaft of the mechanics. This shaft is driven by an intermittent rotational movement and at each stop, that is to say every half-turn of the aforementioned shaft, the reading device must, at the level of each of the blades of the dobby (that is to say of the actuation assembly associated with each heald frame) and according to the design or weave to be obtained on the fabric being woven, securing the actuating element either with said shaft to control the oscillating part, either with the latter in order to operate its angular immobilization.

This selective joining is generally obtained using a movable coupling member in the form of a key or pawl, subjected to the action of two articulated levers arranged on either side of the shaft in order to actuate said movable member at the two stop positions thereof. These two levers are generally coupled to a single rod capable of moving axially in one direction and in the other according to the command received from the reading device of the dobby, elastic return means ensuring the return of the movable member. , levers and connecting rod in a rest position. Such a device is shown for example in document FR-A-2 398 229.

It is easily understood that such a control mechanism operates in poor conditions, in particular as a result of its asymmetrical nature. When the rod in question moves, the two levers are actuated simultaneously while only one of them has a role to fulfill. If for one lever the actuation is operated in one direction by the reading device and in the opposite direction by a spring, for the other lever the actuation mode is necessarily reversed. It is therefore not possible to use springs of perfectly optimized force since their actions do not have the same goal.

It will also be noted that the force of the elastic return means is limited, which affects the precision of the control obtained. It should also be considered that the need to provide a safety mechanism intended to guard in the event that the movable coupling member is actuated and moved in an incomplete manner, further complicates the construction of the entire mechanism. control whose operation remains unreliable in any event.

It is to these drawbacks that the present invention intends to remedy, and this by arranging the pivoting control levers so that they exert a perfectly symmetrical action both on the movable coupling member for its operation for securing the shaft and the actuating element, only on the latter for its angular immobilization.

To this end, these levers, individually actuated by the reading device at one of their ends, are associated with elastic means which tend to return their opposite end in the form of a beak radially towards the shaft. This spout is intended to cooperate with a notch formed in the periphery of a plate laterally secured to the actuating element in order to ensure the angular immobilization of the latter and of the corresponding oscillating part.

It is understood that if care is taken to mount the coupling member on the aforementioned plate so that it is actuated by the spout of one or the other of the two levers, and to associate to said member of the elastic return means which tend to engage its free end or finger in one or the other of two notches made in the shaft or in a drive disc secured thereto, a simple, robust and reliable construction controlled coupling system. It will be noted in particular that the end spout of each lever and the notch of the lateral plate of the actuating element can be given a conical or flared profile which ensures on the one hand the perfectly precise centering of this plate and of 'on the other hand a tendency to eject this spout, the latter effect taking the place of safety in the event of incomplete engagement of the movable coupling member.

Furthermore, the perfectly precise positioning of this member joined to its elastic return in the coupling position makes it possible to give its free end or finger and to each of the notches provided in the shaft or in the drive disc a profile suitable for avoiding any ejection component. Consequently, and unlike conventional systems, there is no need to provide any particular means for locking the movable member in the coupling position.

• Figure 1 est une coupe transversale schématique d'une ratière établie conformément à l'invention.
• Figure 2 est une vue en perspective montrant à l'état démonté les différents éléments constitutifs de l'une des lames de la ratière suivant fig. 1.
• Figure 3 est une coupe axiale partielle représentant, à plus grande échelle, les éléments de fig. 2 une fois montés en place.
• Figure 4 reproduit à échelle agrandie une partie de fig. 1 à une autre position du cliquet.

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:

• Figure 1 is a schematic cross section of a dobby established in accordance with the invention.
• Figure 2 is a perspective view showing in the disassembled state the various components of one of the blades of the dobby according to fig. 1.
• Figure 3 is a partial axial section showing, on a larger scale, the elements of FIG. 2 once mounted in place.
• Figure 4 reproduced on an enlarged scale part of fig. 1 to another position of the pawl.

The dobby considered comprises a main shaft 1 animated by an intermittent rotational movement with stopping every 180 °. At each of the blades of the dobby this shaft 1 receives, with the interposition of an intermediate bearing, an eccentric 2 laterally secured to a plate 3; the cylindrical periphery of the eccentric 2 is engaged, still with the interposition of an intermediate bearing, inside the open part 4a with a circular profile of an actuating rod 4. The free end of this rod 4 is coupled, through a pivoting arm 5, to the pull lever 6 connected to the corresponding heald frame of the envisaged blade.

To each of the eccentrics 2 is associated a drive disc 7 whose axial opening is provided crenellated so as to cooperate with the periphery, itself crenellated, of the shaft 1. The periphery of this disc 7 is cut out of two radial notches 7a, diametrically opposite one another. These notches 7a are intended to selectively receive the terminal finger 8a of a pawl 8 articulated on an axis 9 secured to the lateral plate 3 of the eccentric 2; a spring 10 tends to permanently recall the finger 8a of the pawl 8 in the direction of the shaft 1.

For the control of this pawl 8 there are provided two levers 11 carried at articulation by fixed axes 12 added in the casing of the dobby parallel to the main shaft 1 thereof. Each lever 11 has a square profile and is biased by a spring 13 so as to come into abutment against a corresponding fixed stop 14. These two stops 14 thus define on each lever 11 an actuating tail 11 a and it is conceivable that the two tails, arranged in the same zone A, are capable of being controlled by pushers (shown diagrammatically in the form of arrows 15) of the device for reading the dobby.

• - que chacun des becs 11 et l'entaille 3a présente un profil évasé qui assure un positionnement très précis du plateau 3 et du cliquet 8 porté par ce dernier ;
• - et qu'un talon 8b prévu sur ce cliquet 8 à l'opposé de son doigt 8a se trouve disposé en vis-à-vis de l'entaille 3a, afin que le bec 11 qui s'engage dans ladite entaille repousse le talon précité et opère de la sorte la commande du cliquet au basculement.

The end of each lever 11 opposite the tail 11a is profiled in the manner of a spout 11b, the two spouts 11b corresponding to each of the mechanical blades being arranged on either side of the shaft 1 along the same diametral axis. Each spout 11b is intended to engage in a notch 3a made radially in a projecting ramp or ear 3b of the plate 3 and considering fig. 4 we note:

• - That each of the nozzles 11 and the notch 3a has a flared profile which ensures very precise positioning of the plate 3 and the pawl 8 carried by the latter;
• - And that a heel 8b provided on this pawl 8 opposite to his finger 8a is placed opposite the notch 3a, so that the spout 11 which engages in said notch pushes back the heel mentioned above and operates in this way the control of the ratchet on tilting.

The operation of the above dobby follows from the foregoing explanations and is easily understood.

When the two pushers 15 of the reading device are in the retracted position illustrated in FIG. 1. the springs 13 hold the two levers 11 in contact with the fixed stops 14, so that the spouts 11 of these levers are arranged on the circular path of the ear 3b of the plate 3. Under these conditions when the eccentric 2 and its side plate 3 move angularly, one or the other of the two nozzles 11b will be lifted by the front part of the ear 3b against the spring 13 of the corresponding lever 11, which spring operates the automatic engagement of the spout 11 considered inside the notch 3a.

This engagement, which occurs in conjunction with one of the periodic stops of the shaft 1, operates the subsequent angular immobilization of the eccentric 2, so that the latter is retained at the stop when the shaft 1 is at again rotated. At the same time the aforementioned engagement caused the pawl 8 to tilt by the action of the spout 11b against the heel 8b; the finger 8a of the aforementioned pawl is thus extracted from the notch 7a in which it was engaged. This extraction has the effect of uncoupling the drive disc 7 from the eccentric 2.

If it is assumed that during the next stop of the shaft 1 the same lever 11 is actuated by its pusher 15, the tilting of this lever causes the withdrawal of the spout 11 out of the notch 3a and the elastic return of the pawl 8 at the position for which its finger 8a is engaged in the notch 7a opposite. The eccentric 2 is then coupled to the shaft 1 through the disc 7, the pawl 8 and the plate 3, so that it moves angularly with the shaft causing the displacement of the connecting rod 4 and the control of the pull lever 6 which is attached to it.

It will be noted that the assembly associated with each of the blades of the dobby has perfect symmetry as a result of the angled profile of the levers 11 and of the right angle formed by the pivots 12 relative to the axis of the shaft 1. These two levers are controlled in a single zone A, which obviously simplifies the arrangement of the reading device. The action of the levers 11 is itself symmetrical since their angular displacement takes place under the effect of either the aforementioned pushers 15, or springs 13 which are thus liable to have very precise calibration.

It will be observed on this point that these springs 13 can develop a considerable force which is applied to the pawl8, which is thus controlled under excellent conditions both at engagement and at withdrawal. The conical or flared profile of the spouts 11b and of the notch 3a ensures, in addition to the precise positioning of the pawl, the safety function necessarily introduced into the coupling system, since in the case where as a result of a control fault the finger 8a would remain partially engaged in the notch 7a while the plate 3 of the eccentric 2 would still be retained by one of the spouts 11b, there would be automatic ejection of said spout as a result of the obliquity or taper of the litters in contact at the notch 3a.

It will also be noted that, as a result of the perfectly precise positioning of the pawl 8 and of its finger 8a, the lateral faces of the latter and those of each of the notches 7a of the disc 7 are capable of being oriented so as to avoid any ejection component. . This pawl therefore requires no locking so that the finger 8a remains held in one or the other of the two notches 7a, unlike conventional arrangements.

It should also be understood that the above description has been given only by way of example, the details of execution described may be replaced by any other equivalent within the scope of the claims. It will be noted in particular that if the implementation of the invention proves to be particularly advantageous in the case of rotary dobbies of the kind described in detail above, the fact remains that the finger 8a of each pawl can be arranged to engage in notches made, no longer in the periphery of a drive disc such as 7, but directly in that of the main shaft 1.

It will also be understood that the invention is capable of being applied with advantage to rotary dobbies in which the actuating elements consist of cams against the periphery of which are held in abutment with follower rollers carried by traction levers coupled to the heald frames. It also goes without saying that the coupling members may, in the known manner, take the form of keys movable radially in housings made laterally in the eccentrics or the cams so that they can be operated by the end nozzles 11 of the levers 11 when said spouts engage in the notches 3a.

Claims (4)

1. Rotating dobby for weaving loom, of the type comprising, at the level of each blade, an oscillating rod coupled to the corresponding heddle frame and associated with an actuating eccentric mounted idly on a shaft animated by a jerky movement of rotation, a rocking pawl which, whilst being rendered angularly fast with the eccentric, is placed outside the latter with a view to being adapted, by engagement of a finger of said pawl inside a notch in a drive disc fast in rotation with the shaft, to ensure at the opportune moment the coupling of the latter and of the eccentric with a view to manoeuvring the rod, and two pivoting levers provided on either side of the shaft and placed under the dependence of the reading device for the appropriate control of the rocking coupling pawl as a function of the programme of said device, characterized in that the pivoting levers (11), actuated individually by the reading device (15) at the level of one (11a) of their ends, are associated with elastic means (13) which tend to return radially in the direction of the shaft their opposite end (11 b) in the form of a beak cooperating directly with a notch (3a) made in the periphery of a plate (3) laterally fast with the eccentric (2) with a view to effecting either the perfectly precise, clearance-free angular immobilization of the latter and of the rod under the effect of the above-mentioned elastic means, or its release under the effect of the actuation of the reading device, the above-mentioned plate supporting the mobile coupling member (8) of which one end (8b) is disposed opposite the notch (3a) so that the beak (11 b) ensures, during its engagement or its withdrawal, the rocking of said pawl against or under the effect of the elastic return means (10) associated with this member.

2. Rotating dobby according to Claim 1, characterized in that the finger (8a) and each of the two notches (7a) made in the periphery of the drive disc (7) present a section adapted to generate no effect of ejection, so that said finger remains engaged in the notch without necessitating any locking.

3. Rotating dobby according to either one of Claims 1 and 2, characterized in that the pivoting levers (11) present a square section and are disposed symmetrically with respect to the shaft (1) so that their ends (11 a) are capable of being actuated by the reading device (15) in the same zone (A).

4. Rotating dobby according to any one of Claims 1 to 3, characterized in that the beak (11 b) of the pivoting levers (11) and the notch (3a) of the plate (3) are established with a flared or conical section so as to ensure precise positioning of the eccentric (2) in the immobilized position.

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