EP0071519B1 - Withdrawing carrier for the insertion of the weft in the shed of a shuttleless loom - Google Patents

Description

The invention relates to output clamps for the insertion of the weft in a shuttleless weaving machine, of the type in which the thread is pinched between two facets carried, respectively, by a fixed part and a mobile part, one of these parts affecting the shape of a hook, said facets being inclined relative to the plane of movement of the mobile part.

Clamps of this type are already known, for example from American patent No 4226265 which describes an embodiment in which the pinching of the wire is due to the wedging of the aforementioned inclined facets. It follows that, if the angle of inclination of said facets is too large, taking into account the characteristics of certain wires for example, the wire is insufficiently tight; while on the contrary, if this angle is too small, the jamming forces involved may hinder the opening of the clamp for the release of the wire, especially since, in the embodiment described, the part in the form of a hook is the fixed part, while one end of the movable part is pressed against said hook by the action of a spring in order to ensure the jamming of the wire, so that the relatively long fixed part can not have all the desired rigidity and, therefore, risk following the moving part by preventing the clamp from opening at the moment when the wire should be released.

French patent No. 2040443 also shows a clamp of the type in question in which the hook is pivotally mounted on the body and is subjected to the action of a spring acting in the direction of closing the clamp; there is no question of inclined facets capable of producing a wedging effect, that is to say that the wire is subjected only to a clamping action, which implies a relatively large force of the spring and, consequently, also a risk of deformation of the clamp likely to hinder its correct opening.

The object of the invention is to produce a clamp of the type in question which does not have the aforementioned drawbacks of the systems which have just been mentioned.

To this end, according to the invention, the hook is carried by the movable part constituted by a lever pivoting at an intermediate point of its length, one of the ends of this lever carrying the hook, while the other is subjected to the action of a positive control cam for opening the clamp against the force of a closing spring.

Thanks to this particular structure, a very rigid, precise clamp with high operational reliability is produced. Indeed, not only the inclined facets are capable of ensuring a good grip of the wire, but, since the hook is carried by the movable part of the clamp, we benefit from the pressure of the wire against the hook to accentuate the force which causes it to close. Furthermore, the direct action of the cam on the movable lever ensures faultless opening.

• La fig. 1 représente, vue de dessus, une pince conforme à l'invention.
• La fig. 2 montre la même pince vue de côté.
• La fig. 3 montre la section de l'aiguille porte- pince.
• La fig. 4 est une coupe dans la zone de pincement (section AA de la fig. 1).
• La fig. 5 est une vue de détail de l'extrémité active de la partie fixe de la pince.

The description which follows, as well as the appended figures, will better understand the interest of the invention.

• Fig. 1 shows, seen from above, a clamp according to the invention.
• Fig. 2 shows the same clamp viewed from the side.
• Fig. 3 shows the section of the gripper needle.
• Fig. 4 is a section through the nip (section AA of fig. 1).
• Fig. 5 is a detail view of the active end of the fixed part of the clamp.

The clamp forming the subject of the present invention consists of two parts: the body 1, fixed, secured to the needle 2 and a movable part 3. These two parts are linked in rotation by an axis 4 which passes through the body 1 and which is riveted in 5 to retain part 3.

The gripper body 1 is made up of a part which affects it in the form of a square which matches the internal walls 9 and 10 of the needle 2 (fig. 3). In the representation of fig. 1, the two components 1 'and 2 are joined by screws 11 and 11', but any other known system such as bonding, riveting, etc., can be used. A leaf spring 12, the role of which will be specified below, is fixed to part 1 by screws 13.

The clamp body 1 ends in a part 15 which is the active part for pinching the wire and which cooperates with a hook 14 carried by the movable part 3.

In operation, the clamp moves in directions 6-6 ', as shown in fig. 1, between the comb P and the facade F from which the fabric T is formed. The warp threads 7-7 ′ have also been shown in FIG. 1.

The active part 15 of the pliers (FIG. 5) has a longitudinal edge 101, turned towards the face F and an edge 101 'opposite the first and which limits one of the facets 102 for pinching the wire 19. This facet of pinching, which cooperates with a corresponding opposite facet 16 provided in the hook 14, has two inclinations: one relative to the longitudinal direction of the clamp which gives the end 15 of the fixed part a corner configuration and the other with respect to the plane of movement of the mobile part. In the embodiment described, the value of this latter inclination is approximately 20 ° (fig. 4). This value is defined as substantially equal to or greater than the limit angular value allowing the irreversibility of the corner formed in the groove 14 'of the hook 14 by the part 15 and the inserted wire 19. This angle is a function of the coefficient of friction of the surfaces in contact, that is to say the nature of the material constituting the fixed and movable parts of the clamp and also the nature of the wire. The connection between the straight facet 103 and the inclined facet 102 is produced by a curve 104 which forms, with the corresponding curve of the hook 14, the insertion opening of the wire 19. The area 104 may have a greater inclination than that of the pinch facet 102 to facilitate the insertion of the largest wires.

The end of the movable part 3 opposite the hook 14 rests on the spring leaf 12. It has a part 17 forming a ramp, followed a substantially horizontal portion 18 in the operating position of the clamp.

The clamp which has just been described and which circulates in the crowd with the tip 22 of the hook 14 rotated towards the comb P operates as follows: substantially in the middle of the width, the weft thread 19 brought by an input clamp (not shown) is introduced between the facets 16 and 102, respectively of the movable part 3 and of the fixed part 1. The stretched strand 19 'of the wire 19 which is still connected to the weft reserve (not shown), passes over the hook 14 and contributes to applying it to the fixed part opposite, reinforcing the closing of the clamp which is ensured by the spring 12.

When the clamp has retreated until the hook 14 reaches the level of the selvedge, a roller fixed relative to the frame of the machine (not shown) acts progressively on the ramp 17, then presses on the part 18 of the part. moible 3 and tilts it against the spring 12 around the axis 4 substantially in a plane perpendicular to the plane of the hook 14, in the direction D indicated by an arrow in FIG. 4. The hook 14 lifts and releases the wire 19. In order to increase the precision of the movement of the movable part 3, the latter is guided between two plastic blocks 20, 21, fixed to the clamp body 1.

Thanks to the fact that the hook is carried by the movable part of the clamp and that the tightening of the wire takes place between two inclined facets, it is possible to produce a more rigid clamp, therefore of a safer operation, and lighter than pliers known so far.

It has been said above that the above description applies to the case where the tip 22 of the hook 14 is turned towards the comb side of the weaving machine. However, this clamp can also function if it is produced with the point 22 of the hook 14 turned towards the side of the facade. In this case, it may be advantageous for the plane of the hook 14 to be substantially parallel to the upper ply of the crowd and for the hinge pin 4 to be inclined so that the movable part 3 moves along a plane which is oblique. relative to the plane perpendicular to the plane of the hook 14.

Claims (2)

1. Withdrawing gripper for the insertion of the weft into a shuttle-less loom, in which the thread (19) is gripped between two faces (102, 16), respectively supported by a fixed part (15) and a movable part (3), one of said parts assuming the form of a hook (14), said faces being inclined with respect to the displacement plane of the movable part, characterized in that the hook (14) is carried by the movable part (3) constituted by a lever pivoting at a point (4) mid-length thereof, one of the ends of said lever carrying the hook, whilst the other (18) is subject to the action of a cam, which positively controls the opening of the gripper in opposition to the tension of a closing spring (12).

2. Withdrawing gripper according to Claim 1, characterized in that the gripper thread (19) bears against the hook (14) and reinforces the closing action due to spring (12).

Images