CS228926B2 - Apparatus for controlling the weft inserting gripper motion in shuttleless weaving looms - Google Patents

Abstract

In a shuttleless loom, the movement of the weft conveying grippers is controlled by straps (2) moved backwards and forwards by gearwheels (1) mounted at the loom shed ends, the peripheral teeth of said gearwheels meshing with longitudinally aligned slots (3) provided at the centre of the straps. The engagement between the straps and the gearwheeis is constant and precise over a wide arc of the wheels, thanks to guides extending over the whole of said arc and acting on the lateral portions of the straps, and it takes place between elongated slots in the straps and correspondingly shaped teeth, with round-edged periphery, of the gearwheels.

Description

(54 J Devices for controlling the movement of weft conveying grips on cordless looms

BACKGROUND OF THE INVENTION The present invention relates to a device for controlling the movement of weft conveying grippers on a cordless loom using a pair of gears having reciprocating pivoting movements at the ends of the shed and a pair of gripping needles, the needles having longitudinally aligned slots engaging gear wheels.

On the cordless looms, one of the most serious problems is the control of the reciprocating movement, the escape of the conveying grips, and the problem is the more difficult the higher the weaving speed is.

Many solutions have been proposed, but none of them can be considered satisfactory. Particularly in cases where flexible needles are used to control the grips, the problem of high temperatures that can be produced by continuously repeating gliding between different parts at high speed has not yet been properly solved. In this type of device, it seems important to improve the conditions under which reciprocating rotary motion is transmitted from the gears to the gripper control needles with respect to the engagement accuracy between the gear teeth and the needle slots, the smooth engagement between said teeth and slots and the flexibility of the needles and the fact that this flexibility should be present throughout is 1 hel. Furthermore, it is important to distribute the stresses in the needles and to ensure a uniform engagement between the gears and the needles along the entire length of the engagement.

A device for controlling the movement of weft conveying grips on a cordless loom according to the invention, which satisfies the requirements of both the loom manufacturers and the users in terms of the various listed requirements and presents a modern, rational and satisfactory solution to said problems, even though high and very high weaving are considered. speed, eliminates the drawbacks and drawbacks of known solutions and is based on a guide partially surrounding each of the gears along and at a close distance therebetween and acting on both edge portions of the needles, adjacent to the needles to hold the needles in a consistent and accurate engagement with gears. The notches in the needles preferably have an elongated, rectangular shape, wherein the gear teeth have a corresponding or complementary shape, protruding substantially from the gear wheels and having a periphery with rounded edges.

An exemplary embodiment of the invention is shown in the drawings, wherein Fig. 1 is a front elevational view of a device used on one of the gears; Fig. 2 is a cross-section along line II-II in Fig. 1 showing an engagement

Fig. 4 is a view of one of the gears showing the shape of its teeth; Fig. 4 is a partial view of a needle cooperating with the gears; and FIG. 5 is a cross-sectional view of the needle of FIG. 4.

The device according to the invention comprises, on each side of the loom, a gear 1 for actuating the needle 2 and imparting reciprocating movements thereto and to the gripper to carry the weft yarn into the shed.

The needle 2 has in the middle of a series of elongated rectangular slits 3, which differ in shape and dimensions from all slits, until now used on needles for similar purposes, and which are clearly shown in Figures 4 and 5. engagement with circumferential teeth 4 of corresponding or complementary shape (see FIG. 3) of the gear 1 which partially encircles, the circumferential teeth 4 also being distinguished from the known state by the circumference of the rounded edges.

The circumference of the gear 1, which the needle 2 partially belts, is delimited by a guide 5 which partially surrounds the gear 1 in its close proximity. As shown in FIG. 2, the guide 5 is U-shaped so as to act on the edge portions 6, 7 of the needle 2 next to the slots 3, thereby ensuring a stable and reliable engagement of the base of the peripheral teeth 4 protruding from the periphery of the gear 1. notches 3 needles 2.

By means of the described device, significant advantages are achieved in terms of the correct transmission of the reciprocating movement on the grip conveying the weft yarns on the looms.

First of all, by closely engaging the circumferential teeth 4 of the gear 1 into the notches 3 of the needle 2, which are refined by their shape and which are stable and accurate due to the presence and shaping of the guide 5, the relative position between the needles 2 and the gear 1 is determined. engagement with hitherto unthinkable accuracy, thus allowing a particularly uniform load distribution to the circumferential teeth 4, resulting in less wear, lower temperatures and less noise.

Moreover, the elongated rectangular shape of the notches 3 of the needles 2 substantially reduces their bending stress and facilitates their deformation when engaged with the gears 1, without any detrimental consequences in terms of strength and wear. In practice, these needles 2 bend with greater continuity than needles manufactured by conventional technique and having much smaller and especially less elongated. cutouts.

Finally, the rounded peripheral edges of the circumferential teeth 4 of the gears 1 ensure a smooth grip between the gears 1 and the needles 2 without any shock or wear and the circumferential teeth 4 of the gears 1 protrude significantly from the gears 1.

Claims (3)

I will invent the subject A device for controlling the movement of weft conveying grippers on a cordless loom using a pair of gear wheels, performing reciprocating pivoting movements at the ends of the shed and a pair of gripping needles, wherein the needles have longitudinally aligned slots engaging the teeth of a pair of toothed characterized in that it comprises a guide (5) partially surrounding each of the gearwheels (1) along their circumference and at a close distance therefrom, and acting on both edge portions (6, 7) of the needles (2) adjacent the cut-outs (3) for holding needles (2). in constant and accurate engagement with the gears (1). Device according to claim 1, characterized in that the slots (3) in the needles (2J) have an elongated rectangular shape, the teeth (4) of the gear wheels (1) having a corresponding or complementary shape. Device according to claim 2, characterized in that the teeth (4) protrude significantly from the gears (1) and have a periphery with rounded edges.