EP0851046B1 - Rotary dobby and loom with such a dobby - Google Patents

Description

The present invention relates to a rotary dobby for ordering heald frames mounted on a loom and a loom equipped with such a dobby.

We know that in rotary dobbies, the movement alternating vertical heald frames is provided by oscillating parts which can be formed, depending on the case, by rod-lever assemblies or by roller-bearing levers, these oscillating parts being controlled by elements actuation in the form of an eccentric in the first case or cam in the second. These actuating elements are mounted on a main mechanical shaft which is animated by a intermittent rotation movement and, at each stop, makes all the U-turns, from the aforementioned shaft, the reading must, at each of the dobby blades, that is to say the actuation unit associated with each frame smooth, and depending on the design or weave to be obtained on the fabric being woven, securing the actuating element either with the shaft, to control the oscillating part, or with a fixed point in order to operate the angular immobilization of the latter.

This selective joining is generally obtained at using a movable key-shaped coupling member or ratchet subjected to the action of two pivoting levers arranged on either side of the tree in order to activate this movable member at the two stop positions thereof, each pair of pivoting levers being placed under the dependence of the dobby reading device.

By patent application FR-A- 2,540,524, we know a rotary dobby for loom in which a tray, associated with each heald frame, includes two notches diametrically opposed able to cooperate with the spout of two pivoting levers controlled by a reading device. These two notches have different profiles because one of them they must be relatively deep to give a perfectly precise angular position on the plate and ensure then effective restraint for as long as necessary. The other notch is however established at a depth reduced and has very flared oriented side walls parallel to the end chamfers of the sides of the spout each lever pivoted so that the lever spout can be driven out automatically when the plate is rotated, without action of the reading device on the lever. In this second case, we speak of "passive" engagement of the beak in the notch, because even if the elastic engagement takes place the same way in the two notches, the beak of the second lever is let passively grow here.

Tests have shown that such an arrangement works satisfactorily, but the spout of each lever must present a relatively large height because the spans respectively used with the first and second notches of the plate have heights which add up in the direction of release of the beak in relation to these notches. This induced that the angular movement of each of the levers swivels must have a relatively large amplitude so to allow the clearance of the two spans provided on the spout of each of these levers. The power necessary for such a angular movement is important, hence consumption relatively high energy of the dobby in question.

In addition, these large amplitude angular movements are made by means of violent shocks on the levers pivoting, which leads to premature wear of the elements constitutive of the dobby of the prior art unless these are not particularly robust. In addition, these shocks generate noise, which is tiring for operators whose workstations are located nearby weaving looms fitted with known dobbies.

Finally, the pivoting of the levers is not instantaneous and the greater its amplitude, the more time it takes. This is why a large amplitude pivoting of the levers is likely to limit the speed of use of the dobbies known.

It is to these disadvantages that we hear more particularly remedy the present invention, in order to allow the realization a rotary dobby operating with levers including the pivoting is of relatively small amplitude.

In this spirit, the invention relates to a rotary dobby for a weaving loom comprising, at each of its blades, an oscillating part coupled to a heald frame and associated with an actuating element mounted idly on a shaft of said dobby, a mobile coupling member carried by a plate laterally secured to the actuating element, said movable member being subjected to elastic means for operate the angular connection of said plate with a disc integral with said shaft, and two pivoting levers subjected to the action, on the one hand of the reading device and, on the other hand to that of elastic means which tend to engage the spouts said levers with one of two wedging surfaces of said tray. This dobby is characterized in that the beak of each pivoting lever has an external bearing surface and an internal bearing surface, said bearing surfaces having angles at the top of different values.

Thanks to the invention, the internal and external scopes can respectively cooperate with each of the two surfaces trapping and their arrangement allows their heights do not add up, so the pivoting required for each lever only corresponds to the height of the highest range.

According to a first advantageous aspect of the invention, the internal span is provided in the thickness of the span external. Thanks to this aspect of the invention, the height of the external scope alone defines the angular displacement maximum so that the spout of each lever escapes from surfaces jamming provided at the periphery of the plate.

According to a first advantageous embodiment of the invention the angle at the top of the internal range has a value greater than the angle at the top of the outer staff. According to one variant of the invention, the angle at the top of the internal span has a value less than the angle at the top of the staff external. In any case and according to another advantageous aspect of the invention, it can be provided that the two surfaces of jamming of the plate include a notch capable of receiving the beak of one of the pivoting levers and a pin capable of penetrating in the spout of the other pivoting lever. This provision of wedging surfaces is suitable for cooperation with the forms the spans of the swivel lever spouts.

According to another advantageous aspect of the invention, this notch and this tooth are diametrically opposed on the periphery of the plateau.

The invention finally relates to a loom equipped with a dobby as previously described.

• La figure 1 est une coupe transversale schématique d'une ratière établie conformément à l'invention ;
• La figure 2 est une vue en perspective montrant à l'état démonté, les éléments constitutifs essentiels de l'une des lames de la ratière suivant la figure 1 ;
• La figure 3 représente à plus grande échelle le bec d'un levier pivotant et l'entaille du plateau associé à une lame dans une première position de coincement ;
• La figure 4 est une vue analogue à la figure 3 alors qu'un levier coopère avec une partie du plateau diamétralement opposée à celle représentée à la figure 3 et
• La figure 5 est une vue de l'extrémité d'un levier pivotant d'une ratière rotative conforme à un second mode de réalisation de l'invention.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of two embodiments of a dobby in accordance with its principle, given solely by way of example and made with reference to the accompanying drawings in which:

• 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 essential components of one of the blades of the dobby according to Figure 1;
• Figure 3 shows on a larger scale the spout of a pivoting lever and the notch of the plate associated with a blade in a first wedging position;
• FIG. 4 is a view similar to FIG. 3 while a lever cooperates with a part of the plate diametrically opposite to that shown in FIG. 3 and
• Figure 5 is a view of the end of a pivoting lever of a rotary dobby according to a second embodiment of the invention.

The dobby represented in FIG. 1 comprises a main shaft 1 animated by an intermittent rotational movement with stopping every half-turn. This shaft 1 receives a series of bearings in number equal to that of the heald frames or looms of the loom. On each bearing is mounted an eccentric eccentric 2 laterally secured to a plate 3. On each eccentric 2 is mounted insane the opening of a connecting rod 4 whose free end is harnessed to a pivoting arm 5 which ensures, thanks to a cable 6 a , the vertical displacement of the heald frame 6 of the envisaged blade, shown very schematically. Between two contiguous eccentrics 2, the shaft 1, provided grooved, carries a drive disc 7 which is integral with it and the periphery of which is cut out by two radial notches 7 which are diametrically opposite one another. These notches 7 a are intended to selectively receive the terminal finger 8 a of a pawl 8 articulated on an axis 9 carried by the lateral plate 3 of the corresponding eccentric 2. A spring 10 tends to permanently return the finger 8 a from the pawl 8 in the direction of the shaft 1.

The control of each pawl 8 is ensured using two pivoting levers 11 carried at articulation by axes fixed 12 oriented parallel to the shaft 1. Each lever 11 has a generally angled profile and is stressed by a spring 13 in order to bear against a fixed stop corresponding 14. Each lever 11 comprises an actuating tail 15 likely to be selectively controlled by a pusher belonging to the dobby reading device and represented by arrows 16.

Opposite its tail 15, each lever 11 has a spout 17 capable of cooperating with two wedging surfaces 18 and 19 formed on the periphery of the plate 3. Thanks to the spouts 17 and the wedging surfaces 18 and 19, the plate 3 can therefore be immobilized in two positions separated by a 180 ° rotation of the plate 3 depending on whether the spout 17 shown at left of Figure 1 cooperates with the surface 18 while the spout 17 shown on the right cooperates with the surface 19 or that the beak 17 shown on the left cooperates with surface 19 while the spout 17 shown on the right cooperates with the surface 18.

In the absence of actuation of the pushing device of the reading device, the springs 13 tend, during each stop of the plate 3 opposite the spouts 17, to engage these spouts in cooperation with the wedging surface 19 in the form notch, which has the simultaneous effect of angularly immobilizing the plate 3, and with it the eccentric 2 and the connecting rod 4, and controlling the pawl 8 to uncoupling by withdrawing its finger 8 a from the notch 7 a in which it was introduced. This constitutes an "active" jamming of the plate 3 relative to the lever 11.

Operation is analogous to that described in FR-A-2 540 524. The positioning and extraction of the spout 17 located at proximity of pawl 8 to surface 19 must be produced precisely under the control of the reading. Positioning relative to the surface 18 of the spout located opposite the pawl 8 is transient. It is performed with low power to allow ejection automatic without interaction with the reading device.

To perform the functions listed above and as it appears more clearly in Figures 3 and 4, the geometry of beaks, which are identical since they can selectively cooperate with each of the wedging surfaces 18 and 19, is defined so that they each have a bearing surface external 20 and an internal bearing surface 21 respectively able to cooperate with wedging surfaces 19 and 18.

The external bearing surface 20, represented active in FIG. 3, has a geometry adapted to press against the surfaces delimiting the notch 19. The angle at the top of this bearing surface 20 is noted α. An internal bearing surface 21 is defined in hollow in the spout 17 and we note β its angle at the top. The geometry of the bearing surface 21 is defined so that it is capable of pressing against the external surface of a tooth 18 a belonging to the wedging surface 18 as shown in FIG. 4.

It is noted that the angle at the apex β is greater than the angle at the apex α, so that it is easier to release the spout 17 when it cooperates with the surface 18 than when it cooperates with the surface 19, which is similar to the operating mode of the dobby of the invention in which the wedging obtained with the surface 18 is "passive" while the wedging obtained with the notch 19 is "active".

The bearing surface 21 has a height H ₂ which can be different from the height H ₁ of the bearing surface 20. It is noted in particular that the internal bearing 21 is formed in the thickness of the external bearing 20, that is that is, the height H ₂ is less than the height H ₁ .

In the second embodiment shown in FIG. 5, the apex angle β 'of the internal bearing 21 has a value less than the apex angle α' of the external bearing 20. This configuration can be used when effective or "active" jamming must be carried out on a tooth corresponding to tooth 18 of FIG. 4 while the escape from the bearing surface 20 must be facilitated. This configuration can be used when the wedging surface provided with a tooth is arranged near the end of the pawl 8.

A loom equipped with a dobby as above described can operate faster, with less wear and making less noise than a loom equipped with a dobby of the prior art.

It should also be understood that the description which above was given only as an example and does not in no way limits the scope of the invention. It is understood, in particular, that the invention is likely to be applied to dobbies in which the actuating elements are not made up of eccentrics associated with connecting rods, but by cams profiles for controlling roller levers coupled to heald frames 6. In the same way and although the tilting pawls seem the most embodiment advantageous for movable coupling members, it is possible however have recourse to displacement key mechanism radial. Similarly, the movable coupling member can be composed of several parts, for example two hooks, two latches or two keys.

Claims (7)

1. A rotary dobby for a weaving loom, comprising, at the level of each of its heald shafts, an oscillating member (4) coupled to a heald frame (6) and associated with an actuating element (2) mounted loosely on a main shaft (1) of said dobby, a mobile coupling member (8) carried by a plate (3) laterally integral with the actuating element, said mobile member being subject to resilient means (10) for effecting angular connection of said plate with a disk (7) integral with said main shaft, and two pivoted levers (11) subject, on the one hand, to the action of a reading-in device (16) and, on the other hand, to that of resilient means (13) which tend to engage the tips (17) of said levers with one of two surfaces (18, 19) for wedging said plate, characterised in that said tip of each pivoted lever has an outer bearing surface (20) and an inner bearing surface (21), said bearing surfaces having apex angles (α, β, α', β') of different values.
2. A rotary dobby according to claim 1, characterised in that said inner bearing surface (21) is recessed into the thickness of said outer bearing surface (20).
3. A rotary dobby according to claim 1 or claim 2, characterised in that the apex angle (β) of said inner bearing surface (21) has a value greater than that of the apex angle (a) of said outer bearing surface (20).
4. A rotary dobby according to claim 1 or claim 2, characterised in that the apex angle (β') of said inner bearing surface (21) is has a value lower than that of the apex angle (α') of said outer bearing surface (20).
5. A rotary dobby according to claim 1, characterised in that said two wedging surfaces (18, 19) of said plate (3) comprise a notch (19) capable of accommodating the tip (17) of one of said pivoted levers (11) and a tooth (18a) capable of penetrating into the tip (17) of the other pivoted lever (11) .
6. A rotary dobby according to claim 5, characterised in that said notch (19) and said tooth (18a) are diametrically opposed on the periphery of said plate (3).
7. A weaving loom equipped with a rotary dobby according to any one of the preceding claims.

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