Background Art As is known, in weaving looms the warp threads are moved on a vertical plane, at right angles to the weaving plane, in order to allow the insertion of the weft threads between the warp threads.

The weft threads are moved by using heddle frames, each of which is constituted by a rectangular frame in which two supporting elements, an upper one and a lower one, known as cross-members, are connected laterally by two elements known as shoulders.

A very large number of thin steel rods, known as heddles, is fixed on the inner sides of the cross-members, and a small eye for the passage of a warp thread is provided at the center of said rods. Each heddle is fixed to the cross-members by a coupling that has a play of a few millimeters in order to allow the heddles to slide along an axis that is parallel to the longitudinal axis of the cross-members, so as to facilitate the insertion of the heddles on the cross-members, and along an axis that is perpendicular to the longitudinal axes of the cross-members.

The possibility to move the heddles at right angles to the cross-members arises from the need to avoid subjecting the heddles to excessive stresses.

One should in fact bear in mind that in order to allow a large number of warp threads to remain very close to each other, the transverse cross-section of the heddles is very small and is therefore unable to withstand intense mechanical stresses. At the high movement speeds of heddle frames that have now been reached in weaving, the two cross-members, due to the reciprocating motion

on the vertical plane and due to their inertia, undergo a deformation and tend, depending on the loads, to move closer and further apart.

If the heddles were unable to move at right angles to the cross-members, when the cross-members moved closer such heddles would act with a spring-like effect so as to prevent the deformation of the heddle frame, but would be subjected to a stress that might be excessive in view of their slender cross-section, with the danger of breakage of the heddles that would cause breakage of the warp threads and would therefore force to stop the loom.

In view of the fact that the play between the cross-members and the heddles cannot be increased beyond a certain limit without causing other problems, the continuing demand to increase the productivity of looms and therefore the need to achieve high speeds in the movement of the heddle frames has induced heddle frame manufacturers to gradually stiffen the cross-members and the shoulders in order to prevent the cross-members from undergoing a deformation that causes excessive stresses of the heddles.

However, this solution has the drawback that it causes an increase in the weight of the heddle frame and such weight increase, especially when high production speeds are reached, causes intense mechanical stresses that damage or in any case limit the performance of the machine that generates the movement of the heddle frames, which is commonly termed dobby.

On the other hand, the use of alternative materials, such as for example composite materials, to manufacture heddle frames, has not yet found practical application in this particular field owing to the high costs of such materials.

The play of the heddles with respect to the cross-members, moreover, causes considerable noise, since during the vertical movement of the frame the heddles continuously strike first the upper strip and then the lower strip of the cross-member of the heddle frame, causing a considerable increase in the noise generated by the loom, which is already very noisy per se, with

negative consequence for the working environment.

Disclosure of the Invention The aim of the present invention is to solve the problems described above by providing a heddle for weaving looms that allows to simplify considerably the structure of heddle frames and to reduce their weight with respect to conventional heddle frames, so as to allow to achieve high weaving speeds without problems.

Within this aim, an object of the invention is to provide a heddle for weaving looms that also allows to reduce significantly the noise generated by looms during their operation.

Another object of the invention is to provide a heddle for weaving looms that by reducing the weight of the heddle frame also allows to reduce the stresses of the machine that generates the movement of the heddle frames.

Another object of the invention is to provide a heddle frame that is designed to support heddles according to the invention.

This aim and these and other objects that will become better apparent hereinafter are achieved by a heddle for weaving looms that is provided with an elongated laminar body, characterized in that said laminar body is provided with stiffening means that are adapted to increase its flexural strength, said laminar body being further provided, proximate to one of its longitudinal ends, with means for engaging a supporting cross-member and having, proximate to its opposite longitudinal end, a passage for the warp thread, said laminar body having, proximate to its longitudinal end that can engage said cross-member, a substantially flat contact region that lies on a plane that is substantially perpendicular to the longitudinal extension of said laminar body and can engage against the upper or lower face of said cross- member.

Brief description of the Drawings Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment

of a heddle for weaving looms according to the invention, illustrated by way of non-limitative example in the accompanying drawings, wherein: Figure 1 is a front elevation view of a heddle according to the invention ; Figure 2 is an enlarged-scale sectional view of Figure 1, taken along the line II-II ; Figure 3 is an enlarged-scale sectional view of Figure 1, taken along the line 111-111 ; Figures 4 and 5 are transverse sectional views of a cross-member of a heddle frame with a heddle according to the invention fitted thereon, showing respectively the heddle released with respect to the cross-member and the heddle locked on the cross-member.

Ways of carrying out the Invention With reference to the figures, the heddle according to the invention, generally designated by the reference numeral 1, comprises an elongated laminar body 2 provided with stiffening means that are adapted to increase the flexural strength of the laminar body 2.

The laminar body 2 has, proximate to one of its longitudinal ends, means 3 for engagement with a supporting cross-member 4 and has, proximate to its opposite longitudinal end, a passage 5 for the warp thread.

The laminar body 2 further has, proximate to its longitudinal end that can engage the cross-member 4, a substantially flat contact region 21 that lies on a plane that is substantially perpendicular to the longitudinal extension of the laminar body 2 and can engage against the upper or lower face of said cross- member 4, depending on whether the heddle 1 lies above or below the cross- member 4.

Conveniently, the stiffening means for increasing the flexural strength of the laminar body 2 comprise at least one longitudinal folds or bends of the laminar body 2. Preferably, there are two longitudinal folds or bends 6a and 6b, which have opposite bending directions.

More particularly, the laminar body 2 has a substantially S-shaped

transverse cross-section.

Preferably, the laminar body 2 has a central region that is affected by or comprises the two bends 6a and 6b and two lateral regions 7a and 7b that are substantially flat and preferably lie on two spaced parallel planes.

The two planes of arrangement of the lateral regions 7a and 7b are preferably spaced, on opposite sides, with respect to an imaginary central plane that passes through the longitudinal axis of the laminar body 2 and is parallel to the two planes of arrangement of the lateral regions 7a and 7b.

More specifically, in the laminar body 2 the two substantially flat lateral regions 7a and 7b are connected by a central region in which the two bends 6a and 6b are provided with curvatures that have opposite concavities.

It should be noted that the arrangement of the lateral regions 7a and 7b on two different planes of arrangement also facilitates the insertion of the warp thread through the passage 5.

The engagement means 3 comprise a portion that is shaped like a pair of opposite hooks 8a and 8b forming, at the longitudinal end of the heddle 1 that is designed to be connected to the cross-member 4, a substantially C- like shape.

The bends 6a and 6b also form, at the region affected by the engagement means 3, the region 21 for contact of the laminar body 2 against the upper or lower face of the cross-member 4. In particular, with reference to the illustrated embodiment, it can be noted that the contact of the laminar body 2 against the cross-member 4 occurs along a line that has a double curvature, which increases considerably the stability of the contact of the laminar body 2 against the cross-member 4.

Thanks to the high flexural rigidity, achieved in particular by means of the bends 6a and 6b, the heddle according to the invention can be supported in a cantilevered manner by the cross-member 4, revolutionizing the execution of heddle frames. A heddle frame designed to support heddles according to the invention can in fact be limited, as regards heddle support,

to the provision of a single cross-member 4, which supports the heddles according to the invention in a cantilevered fashion at one of their longitudinal ends, while the other longitudinal end of the heddles is free and is provided with the passage 5 for the warp threads.

Conveniently, the cross-member 4 is provided with means for detachably locking the heddles 1.

Said detachable locking means comprise two shoulders lla and llb, which are formed on the front face and on the rear face of the body 20 of the cross-member 4 and are designed to be engaged by the two hooks 8a and 8b, and a locking profiled element 12, which is interposed between the body 20 of the cross-member 4 and the heddles 1 and can move on command parallel to the longitudinal extension of the heddles 1 with respect to the body 20 of the cross-member 4, so as to engage or disengage the opposite hooks 8a and 8b with the shoulders 1 la and 1 lob.

More particularly, the locking profiled element 12 has a substantially I- shaped transverse cross-section and is accommodated, with one of its portions, inside a longitudinal compartment 13 provided for this purpose in the body 20 of the cross-member 4. One wing of the locking profiled element 12 protrudes from the compartment 13 and forms the contact plane for the contact region 21 of the laminar body 2 of the heddles proximate to the opposite hooks 8a and 8b. Substantially, the heddles 1 rest against the wing of the locking profiled element 12 that protrudes from the compartment 13.

It should be noted that the contact of the heddle according to the invention against the upper or lower face of the cross-member 4, which in the illustrated embodiment is constituted by the wing of the locking profiled element 12 that protrudes from the compartment 13, achieves high stability for the heddle.

The other wing of the locking profiled element 12 is accommodated in the compartment 13. Moreover, the locking profiled element 12 can slide

with its core, which connects the two wings, along a direction that is perpendicular to the longitudinal extension of the cross-member 4 in an appropriately provided slot 14 through which the compartment 13 is connected to the outside.

The cross-member 4 is further provided with an actuating profiled element 15, which is accommodated inside the compartment 13 and can be actuated to produce the movement of the locking profiled element 12 parallel to the longitudinal extension of the heddles 1, i. e. , at right angles to the longitudinal extension of the cross-member 4, with respect to the body 20 of the cross-member 4.

The actuating profiled element 15 has a transverse cross-section that forms at least one region that is eccentric with respect to its longitudinal axis 15a about which said actuating profiled element 15 can be rotated with respect to the body 20 of the cross-member 4.

In the illustrated embodiment, the actuating profiled element 15 has two eccentric regions, which are arranged on opposite sides with respect to the longitudinal axis 15a. By way of the rotation of the actuating profiled element 15 about the axis 15a with respect to the body 20 of the cross- member 4, it is possible to achieve the engagement of these two eccentric regions respectively with the bottom of the compartment 13 and with the wing of the locking profiled element 12, which is accommodated in the compartment 13, so as to push the locking profiled element 12 toward the outside of the compartment 13, thus engaging the opposite hooks 8a and 8b against the shoulders lla and lib, or it is possible to allow the locking profiled element 12 to retract further into the compartment 13, thus disengaging the opposite hooks 8a and 8b from the shoulders 1 la and 1 lb in order to allow the heddles to be fitted on the cross-member 4 or disengaged from it.

In practice, it has been found that the heddle according to the invention fully achieves the intended aim, since thanks to its particular structure that

ensures high flexural strength and high stability in coupling to the cross- member it can be supported in a cantilevered manner, thus allowing to limit the heddle frame of weaving looms to the provision of a single cross- member and therefore allowing to reduce considerably the weight of heddle frames. This also eliminates the problem of stress affecting the heddles due to the movement of the cross-members toward or away from each other that can be observed in conventional heddle frames.

Another advantage of the heddle according to the invention is to eliminate the noise generated by mutual movements of the heddles and the cross-member, thus reducing the overall noise of looms during their operation.

The heddle thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the materials used, as well as the dimensions, may be any according to requirements and to the state of the art.

The disclosures in Italian Patent Application No. MI2002A001175 from which this application claims priority are incorporated herein by reference.