TECHNICAL FIELD AND PRIOR ART

The invention relates to a connecting rod for a drive mechanism for a harness frame of a weaving machine, to a drive mechanism for a harness frame of a weaving machine comprising such a connecting rod, and to a method for manufacturing such a connecting rod.

As generally known, a shed forming device comprises several harness frames, which are moved up and down by means of a drive mechanism. For each harness frame, the drive mechanism comprises several connecting rods and levers via which the harness frame is coupled to a drive motor. In one embodiment several drive motors are provided, in particular one drive motor for each harness frame. In other embodiments, several or all harness frames are coupled to a common drive motor.

To allow for a weaving at high weaving speeds, and, thus, a movement of the harness frames with high speed and/or acceleration, connecting rods having a sufficient stiffness are necessary. On the other hand, a weight of the connecting rods, which are moved together with the harness frames, shall be kept small.

EP 1988195 B1 shows a connecting rod for a drive mechanism for a harness frame of a weaving machine with two swivel levers, the connecting rod comprising two tubular shafts connecting the two swivel levers, which are distanced in a vertical direction, and at least one spacer arranged between the two shafts, wherein at open ends of the two shafts connectors are provided for connecting the connecting rod to the swivel levers of the drive mechanism. Each connector comprises two parallel arranged lugs, which are fixed to an intermediate element by means of rivets, wherein the intermediate element has two jaws, which are inserted into the open ends of the two tubular shafts and glued to the interior of the shafts.

US 5,255,719 shows a connecting rod comprising a flattened tube and two connectors attached to either end of the flattened tube. Each connector comprises two lugs with a first section and a second section, wherein the first sections are arranged to allow assembly of a pivot intended for coupling of a corresponding lever. For a connection of the connector and the flattened tube, the second sections of the lugs are provided with two deformable blocking jaws, which penetrate inside the flattened tube and cooperate with spacer or expander screws accessible through perforations made in the wall of the flattened tube. SUMMARY OF THE INVENTION

It is the object of the invention to provide a rigid, light-weight connecting rod for a drive mechanism for a harness frame of a weaving machine. It is further the object of the invention to provide a method for manufacturing such a rigid, light-weight connecting rod for a drive mechanism for a harness frame of a weaving machine.

According to a first aspect, a connecting rod for a drive mechanism for a harness frame of a weaving machine comprising a profile with a cross-section having two long sides and two narrow sides, and with a first end, and a connector attached to the first end of the profile is provided, wherein the connector comprises two plate-shaped lugs, each lug having a first section and a second section, wherein the first sections project from the first end and are arranged for connecting the connecting rod to an element of the drive mechanism, and wherein the second sections each have an attachment surface, each attachment surface being complementary in shape to one long side of the profile and being glued to said long side of the profile.

The profile in embodiments of the invention has a second end, wherein a further connector, similar in design to the connector attached to the first end, a connector differing in design or no connector is attached to the second end. In case no connector is attached to the second end, the second end of the profile itself functions as a connector. The expression“first”,“second”, etc. used in the context of the application are only used for distinguishing one element from other elements and do not limit the sequence and/or importance of the elements.

The profile having a cross-section with two long sides and two narrow sides preferably is a profile with an at least essentially rectangular cross-section. In one embodiment, the cross- section is constructed of a rectangle with curved narrow sides. In other embodiments, the long sides and the narrow sides are slightly curved. In another embodiment, the long sides are concavely curved towards a center of the profile. In still another embodiment, the long sides and the narrow sides are all planar and arranged perpendicular to one another. In still another embodiment, the corners between the long sides and the narrow sides of the profile are slightly rounded to avoid notch effects.

The length of long sides of the profile depends inter alia on the type of the connecting rod. In particular, a length is chosen to allow for a sufficient bending strength, while keeping a weight of the profile low. For example, a length of the long sides is between 55 mm and 65 mm for a connecting rod used for connecting two levers arranged at opposite sides of the harness frame. The lugs are plate-shaped. In the context of the application, plate-shaped describes a thin object, which is either flat or bended. The long sides of the first end are arranged for example in parallel with surfaces of the plate-shaped lugs facing each other for forming a fork, wherein an adjoining element, for example a swivel level is clamped within the fork.

In the context of the application, gluing describes a technique for connecting two elements of the same or different material with applying an intermediate layer of adhesive or glue. Gluing is also referred to as adhesive bonding, glue bonding or simply bonding. By gluing, two elements of different material can be connected while avoiding mechanical stress and/or cut-outs required for a mechanical connection using rivets or screws. The type of adhesive or glue can be suitably chosen by the person skilled in the art depending on the materials of the elements to be connected.

The long sides of the profile, to which the second sections are attached with their attachment surface, provide a sufficiently large contact surface to ensure a reliable gluing of the second sections to the long sides of the profile.

In one embodiment, the profile has an l-shaped cross-section, wherein the lugs are attached to outer surfaces of the long sides of the profile.

In preferred embodiments, the profile is a hollow profile, in particular a hollow profile made of lightweight metal, such as aluminum or aluminum alloy. Such a hollow profile for example is a drawn hollow profile. When providing a hollow profile, a weight of the profile can be reduced while ensuring a sufficient stiffness. Providing lightweight connecting rods allows a limiting of inertial forces of the drive mechanism when weaving, so that the drive mechanism can be actuated using less power. This is in particular advantageous for high speed weaving with a drive mechanism having one drive motor for each harness frame as such motors preferably have a limited power. This further allows the applied forces to be kept rather low even for high speed weaving. This is also advantageous when a dobby of another shedding mechanism is used for driving harness frames. The lugs of the connector in preferred embodiments are made of a different material, in particular steel, wherein gluing allows for a connection of the elements of different material.

Preferably, the hollow profile has an at least essentially rectangular cross-section, wherein inner corners of the hollow profile are slightly rounded to avoid notch effects. In one embodiment, protrusions and/or cavities are provided at the inner side surfaces of the hollow profile to allow for an accumulation of glue for gluing the second sections of the lugs against the inner side surfaces of the hollow profile. In alternative or in addition, the lugs are provided with protrusions and/or cavities at the attachment surface. The protrusions and/or cavities in one embodiment also are used for aligning the lugs with respect to the profile.

In preferred embodiments, the second sections are received within the first end of the hollow profile, and the second sections are glued to inner side surfaces of the long sides of the hollow profile.

In one embodiment, the second sections of the two lugs abut against each other when received within the first end of the hollow profile. In preferred embodiments, a length of the narrow sides of the hollow profile is longer than a combined thickness of the two second sections of the two lugs received within the first end. Hence, when received within the first end of the hollow profile, the second sections are distanced from one another.

In one embodiment, the two lugs are connected to each other, for example by spot welding, wherein depending on a distance between the lugs additional cross pieces are added. When connecting the two lugs, a distance between the two lugs is fixed at a location where the two lugs are connected to each other. Connecting the two lugs to each other has the advantage that when forcing the two lugs apart for mounting the first sections on an element of the drive system, for example on a bearing of a swivel lever, the glue connection between the hollow profile and the lugs is less loaded compared to an embodiment, in which the two lugs are separate from another and only fixed to the hollow profile by means of the glue connection.

In preferred embodiments, the connector comprises an intermediate element, which is arranged between the second sections of the two lugs. The intermediate element in preferred embodiments is designed such that the lugs are pressed against the inner side surfaces of the hollow profile. The intermediate element offers extra strength of the glue connection. In one embodiment, the intermediate element is removably arranged between the lugs, wherein the intermediate element for example is removed after drying of the glue. In other embodiments, after drying of the glue the intermediate element remains in the hollow profile, so that it provides additional strength for avoiding that the glued lugs come loose from the inner side surfaces of the hollow profile.

In one embodiment, the intermediate element and the lugs are provided with complementary alignment elements, in particular with taps and openings. In one embodiment, the second sections of the lugs have openings that can enter into taps of the intermediate element, so that the lugs are aligned with respect to the intermediate element. In alternative, protrusions are provided on the second sections of the lugs. In still another embodiment, the intermediate element and the lugs both comprise a combination of taps and openings.

In one embodiment, the intermediate element is provided with an end stop at its front face for a defined positioning of the intermediate element within the first end of the hollow profile. In this embodiment, the intermediate element is used for positioning the lugs with respect to the hollow profile.

Preferably, the intermediate element is a made of a relative stiff material, in particular a synthetic material. Hence, the intermediate element can only be deformed within limits for mounting the intermediate element within the hollow profile. The intermediate element forces the second sections of the lugs against inner side surfaces of the hollow profile for reinforcing the glue connection.

In one embodiment, each lug is a flat plate-shaped element, wherein a distance between the second sections is equal to a distance between the first sections. In preferred embodiments, each lug is a bended plate-shaped element, wherein the distance between first sections of the lugs is larger than the distance between the second sections arranged within the hollow profile. Preferably, the lugs are formed and arranged mirror-symmetrically with respect to a center line, wherein both lugs are provided with two bends such that the first sections and the second sections are arranged in parallel.

In one embodiment, the second sections have an at least essentially rectangular form. In other embodiments, the second sections have a tapered distal end. By providing a tapered distal end, a length of the second sections is increased while keeping an overall weight of the element low. In case a hollow profile is provided, the tapered distal ends further ease an insertion of the connector into the hollow profile and enhance spreading of the glue applied to the interior surfaces of the first end. In one embodiment, a distance between the distal ends decreases in the direction away from the first sections. Thereby, the effect of the tapered distal ends is further increased.

In one embodiment, the distal ends are connected to each other by means of a connecting part. Hence, the two lugs together form an integral unit, wherein the two lugs are well aligned with each other. The two lugs and the connecting part in one embodiment are manufactured as an integral and bent element, in particular a bent plate-shaped element. In other embodiments, the two lugs are manufactured separately. ln one embodiment, the connecting rod at the second end is not provided with a connector or provided with a connector that differs from the connector provided at the first end. In other embodiments, two connectors are provided, which are attached to the first end and the second end of the profile, respectively, each connector comprising two lugs with a first section and a second section, wherein the second section are glued to said profile.

According to a second aspect, a method for manufacturing a connecting rod for a drive mechanism for a harness frame of a weaving machine comprising a profile with a cross-section having two long sides and two narrow sides, and with a first end, and a connector, wherein the connector comprises two plate-shaped lugs, each lug having a first section and a second section is provided, wherein the connector is attached to the first end of the profile such that the first sections project from the first end and are arranged for connecting the connecting rod to an element of the drive mechanism, and wherein attachment surfaces of the second sections, which attachment surfaces each are complementary in shape to one long side of the profile, are glued to said long side of the profile.

In preferred embodiments, the profile is a hollow profile, wherein the second sections are inserted into the first end of the hollow profile, and the second sections are glued to inner side surfaces of the hollow profile, in particular while the hollow profile is held within a mold or a clamp. Using the mold or the clamp, a deformation of the hollow profile upon inserting the lugs and attaching the lugs to the inner side surfaces is avoided. Further, the mold or clamp can be used for applying a force to the hollow profile from outside. This is advantageous as generally a quality of an adhesive connection or a glue connection depends on the forces applied upon connecting the elements. When holding the hollow profile in a mold or clamp, high forces can be applied while avoiding a deformation due to said high forces.

In one embodiment, the lugs are attached to an intermediate element, which is arranged between the second sections of the two lugs, wherein the lugs together with the intermediate element are inserted into the first end of the hollow profile. The intermediate element allows for a precise positioning. Preferably, the intermediate element is an elastically deformable element, wherein restoration forces of the intermediate element are used for forcing the lugs against the inner side surfaces of the hollow profile. In one embodiment, the intermediate element is removed after the glue or adhesive is dried.

According to a third aspect, a drive mechanism for a harness frame of a weaving machine comprising at least one connecting rod with a profile and a connector comprising two lugs is provided. Preferably, said connecting rod is connecting two levers arranged at opposite sides of the harness frame. This connecting rod is longer than other connecting rods of the drive mechanism, in particular in wide weaving machines. Therefore, an overall inertia of the system can be significantly reduced when designing this connecting rod as a lightweight connecting rod. However, the invention is not limited to the design of this connecting rod. BRIEF DESCRIPTION OF THE DRAWINGS

In the following, an embodiment of the invention will be described in detail with reference to the drawings. Throughout the drawings, the same elements will be denoted by the same reference numerals.

Fig. 1 shows a drive mechanism according to the invention;

Fig. 2 shows a connecting rod according to a first embodiment of the invention;

Fig. 3 shows the end of the connecting rod of Fig. 2 in partly exploded view;

Fig. 4 shows the end of the connecting rod of Fig. 2 in exploded view;

Fig. 5 shows an end of the connecting rod similar to the connecting rod of Fig. 2;

Fig. 6 shows a connecting rod partly in cross section according to a second embodiment of the invention;

Fig. 7 shows an enlarged view of a part of the connector of Fig. 6.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Fig. 1 shows a part of shed-forming device 1 for a weaving machine with a harness frame 2 and a drive mechanism 3 for the harness frame 2. In a weaving machine, a number of harness frames 2 and an equal number of drive mechanisms 3 are provided. For example, one drive mechanism 3 is assigned to one harness frame 2 and is driven by a drive motor 4. Each harness frame 2 can move between an upper position and a lower position.

The drive mechanism 3 for driving the harness frame 2 as shown in Fig. 1 comprises a crank 10 rotating about a crank axis 5, a connecting rod 1 1 , and a first swivel lever 12 rotating about a first swivel axis 6. The first swivel lever 12 has a first arm 15, a second arm 16 and a third arm 17. The drive mechanism 3 further comprises a second swivel lever 13 rotating about a second swivel axis 7. The second swivel lever 13 has a first arm 18 and a second arm 19. The drive mechanism 3 further comprises a connecting rod 14 connecting the first arm 15 of the first swivel lever 12 to the first arm 18 of the second swivel lever 13, so that the second swivel lever 13 moves conjointly with the first swivel lever 12. The connecting rod 1 1 is connected to the third arm 17 of the first swivel lever 12 via a mounting element 8, which mounting element 8 can slide along the third arm 17 and is fixable in position at the third arm 17.

The harness frame 2 is coupled to the second arm 16 of the swivel lever 12 by means of a connecting rod 20 and a guiding element 21 that is guided in the weaving machine. The second arm 19 of the second swivel lever 13 is connected via a connecting rod 22 and a guiding element 23 to the harness frame 2. The guiding elements 21 , 23 are preferably made of a lightweight metal, for example an aluminum alloy. The connecting rod 1 1 is linked to the crank 10 by a first hinged joint 30, which first hinged joint 30 is arranged eccentric to the crank axis 5. Further, the connecting rod 1 1 is linked via the mounting element 8 to the third arm 17 of the swivel lever 12 by a second hinged joint 31.

The first swivel lever 12 is linked to the connecting rod 14 by a first hinged joint 32, while the second swivel lever 13 is linked to the connecting rod 14 by a second hinged joint 33. Further, the first swivel lever 12 is linked to the connecting rod 20 by a first hinged joint 34, which connecting rod 20 is linked by a second hinged joint 35 to the guiding element 21. Similarly, the second swivel lever 13 is linked to the connecting rod 22 by a first hinged joint 36, which connecting rod 22 is linked by a second hinged joint 37 to the guiding element 23.

One, several or each of the connecting rods 11 , 14, 20, 22 can be designed as a lightweight connecting rod comprising a profile and one connector or two connectors attached to the profile as described in more detail below with reference to Figs. 2 to 4. Preferably, at least the connecting rod 14 connecting the first swivel lever 12 to the second swivel lever 13 is designed as a lightweight connecting rod 14 comprising a hollow profile 40 and two connectors 41 , 43. The connector 41 is attached to the first end 42 of the hollow profile 40 and the connector 43 is attached to the second end 44 of the hollow profile 40. The hollow profile 40 is made for example of aluminum alloy.

In the embodiment shown in Fig. 1 , a fixation element 50 is provided on the connecting rod 14 for cooperating with a stabilizer (not shown). In other embodiments, no stabilizer is provided. In alternative, in one embodiment the hollow profile 40 is deformed for example by hydroforming or in any other appropriate way, such that a height of the connecting rod 14 in the movement direction of the harness frame 2 is larger at a middle section, for example as known from BE 1016228 A3. The connecting rod 14 is shown in more detail in Figs. 2 to 4.

As shown in Fig. 2, the connecting rod 14 comprises a hollow profile 40 with an oblong cross- section having two long sides 45, 46 and two narrow sides 47, 48. The hollow profile 40 has a first end 42 and a second end 44, wherein a connector 41 is attached to the first end 42 and a connector 43 is attached to the second end 44.

In the embodiment shown, each connector 41 , 43 comprises two plate-shaped lugs 51 , 52 and an intermediate element 53 arranged between the lugs 51 , 52. The lugs 51 , 52 are made for example of steel and the intermediate element 53 is made for example of an elastically deformable material, in particular a synthetic material.

As shown in Figs. 3 and 4, each lug 51 , 52 has a first section 54, 56 and a second section 55, 57, wherein as shown in Fig. 2, after mounting the connector 41 to the hollow profile 40, the first sections 54, 56 project from the first end 42 of the hollow profile 40.

In the embodiment shown, each lug 51 , 52 is a bended plate-shaped element. The lugs 51 , 52 are provided with two bends, wherein first sections 54, 56 and the second sections 55, 57 are both arranged in parallel and the distance between first sections 54, 56 of the lugs 51 , 52 is larger than the distance between the second sections 55, 57 of the lugs 51 , 52.

The first sections 54, 56 are arranged for connecting the connecting rod 14 to an adjoining element of the drive mechanism, more particular to the swivel levers 12, 13 (see Fig. 1 ). In the embodiment shown, the first sections 54, 56 are arranged in parallel, i.e. with surfaces of the plate-shaped lugs 51 , 52 facing each other, and at a distance from one another, such that the swivel levers 12, 13 can be clamped between the first sections 54, 56. In the embodiment shown, the first sections 54, 56 are provided with inner borders 58, 59 protruding from opposing surfaces of the first sections 54, 56, for a connection with the swivel levers 12, 13. For mounting the connecting rod 14 to the swivel levers 12, 13, a gap formed between the first sections 54, 56 has to be widened. The bends of the lugs 51 , 52 facilitate a widening of the gap for mounting the connecting rod 14 to the swivel levers 12, 13, while avoiding high forces acting on the second sections 55, 57 during the mounting.

The second sections 55, 57 of the connector 41 are received within the first end 42 of the hollow profile 40. For fixing the connector 41 to the hollow profile 40, the second sections 55, 57 are glued to inner side surfaces of the long sides 45, 46 of the hollow profile 40. For this purpose, the second sections 55, 57 each have an attachment surface 60, wherein each attachment surface 60 is complementary in shape to one long side 45, 46 of the hollow profile 40.

In the embodiment shown, the attachment surface 60 and the long sides 45, 46 of the hollow profile 40 each are essentially flat, wherein the inner side surface of the long sides 45, 46 are provided with protrusions 61 for forming cavities 62 between the protrusions 61 , in which cavities 62 an adhesive can be accumulated.

The intermediate element 53 and the lugs 51 , 52 are provided with complementary alignment elements. In the embodiment shown, the intermediate element 53 is provided with three taps 63 at each of its side surfaces which are inserted in openings 64 provided on the second sections 55, 57 of the two lugs 51 , 52, when mounting the intermediate element 53 between the lugs 51 , 52.

At a front face of the intermediate element 53 and end stop 65 is provided, wherein an insertion depth of the intermediate element 53 within the first end 42 of the hollow profile 40 is limited by means of the end stop 65. For manufacturing the connecting rod 14, in one embodiment the hollow profile 40 is placed in a mold or support (not shown), which mold has an inner shape which is equal to the outer shape of the hollow profile 40.

The lugs 51 , 52 are mounted to the intermediate element 53, wherein the taps 63 of the intermediate element 53 enter into the openings 64, so that the lugs 51 , 52 are aligned to one another.

An adhesive or glue (not shown) is applied to the interior of the first end 42 of the hollow profile 40, in particular at least at the location of the cavity 62, and the connector 41 comprising the lugs 51 , 52 and the intermediate element 53 is inserted into the hollow profile 40. For an insertion, the intermediate element 53 is elastically deformed wherein after the insertion the restoration forces of the intermediate element 53 force the attachment surfaces 60 of the second sections 55, 57 of the lugs 51 , 52 against the inner side surfaces of the hollow profile 40. After insertion the attachment surfaces 60 are pressed against the protrusions 61 of the hollow profile 40, and the glue present between the attachment surfaces 60 of the lugs 51 , 52 and the long sides 45, 46 of the hollow profile 40 provides the glue connection. During mounting of the connector 41 , the hollow profile 40 is pressed against an inner wall of the mold, in order to allow an outer shape of the hollow profile 40 to assume substantially the shape of the mold.

In order to apply a force during a drying of the glue or adhesive, in one embodiment, an outside pressure is provided on the outer side surfaces of the long sides 44, 45 of the hollow profile 40.

In the embodiment shown in Figs. 2 to 4, the attachment surfaces 60 have an essentially rectangular shape.

In Fig. 5 a first end 42 of a connecting rod 1 1 , 14, 20 or 22 is shown that is designed as a lightweight connecting rod and that comprises a hollow profile 40 and a connector 41 attached to the first end 42. The connector 41 is attached to the first end 42 of the hollow profile 40 in a way similar to the connector 41 as shown in Figs. 2 to 4. At the second end of the hollow profile 40 a further connector, similar in design to the connector 41 , a connector differing in design or no connector is attached. In case no connector is attached, the second end itself can function as a connector. For example, the connecting rods 11 , 20 and 22 (see Fig. 1 ) can be provided at the first end 42 with a connector 41 according to the invention, in particular at the end near a swivel lever 12 or 13, whereas at the second end a different connector is provided. On the other hand, the connecting rod 14 connecting the two swivel levers 12, 13 (see Fig. 1 ) can be provided at both ends 42, 44 with a connector 41 , 43 according to the invention.

Fig. 6 shows two ends 42, 44 of a connecting rod 14 with two connectors 41 , 43 partly in cross section according to a second embodiment. Fig. 7 shows the connector 41 of Fig. 6. The connectors 41 , 43 are similar in design to the connectors 41 , 43 shown in Figs. 1 to 5 and for the same or similar elements, the same reference signs are used and reference is made to the description above. In contrast to the first embodiment, the second sections 55, 57 of the lugs 51 , 52 have a tapered distal end 24, 25. The form of the tapered distal ends 24, 25 is only by example and other shapes of the distal ends are feasible.

As shown in more detail in Fig. 7, the distal ends 24, 25 of each lug 51 , 52 are connected to each other by a connecting part 26. The lugs 51 , 52 and the connecting part 26 in one embodiment are manufactured from an integral element, in particular an integral element originating from a plate-shaped element, which is bent to arrange the two lugs 51 , 52 to face each other. In other elements the lugs 51 , 52 are manufactured separately and connected by means of the connecting part 26, for example by means of welding the connecting part 26 between the two lugs 51 , 52. The two connected lugs 51 , 52 are well aligned with respect to each other.

A distance between the distal ends 24, 25 decreases towards the end so that the distal ends 24, 25 together form a wedge, which eases an insertion of the connectors 41 , 43 into the hollow profile 40. In addition, the shape of the distal ends 24, 25 enhances spreading the glue applied to the interior of the ends 42, 44 of the hollow profile 40. Similar as in Figs. 2 to 4, an intermediate element 53 can be arranged between the two lugs 51 , 52 and being positioned between the mutually connected lugs 51 , 52 by taps 63 of the intermediate element 53 entering into openings 64 of the lugs 51 , 52. The person skilled in the art will understand that the drive mechanism according to the invention can be used in several types of weaving machines, such as in air-jet weaving machines, rapier weaving machines, waterjet weaving machines, projectile weaving machines and other types of weaving machines. The drive mechanism according to the invention or the connecting rod according to the invention can also be mounted on existing weaving machines. The long sides 45, 46 of the profile 40 and the attachment surfaces 60 of the connector 41 at which the connector 41 and the profile 40 are glued together, in alternative embodiments in addition are provided with elements for mechanical connection, in particular a snap-fit or form-fit connection. For example, in one embodiment, the attachment surface 60 of the connector 41 is locally deformed for forming ribs, protruding from the attachment surface 60, which are inserted in respective cut-outs or indentations provided on the long sides 45, 46 of the hollow profile 40. In alternative, the long sides 45, 46 of the hollow profile 40 are locally deformed for forming ribs, protruding towards an inside of the hollow profile 40, which are inserted in respective cut-outs or indentations provided on the attachment surface 60 of the connector 41.

The connecting rod, the method and the drive mechanism according to the invention are not limited to the embodiments described by way of example and illustrated in the drawings. Alternatives and combinations of the described and illustrated embodiments that fall under the claims are also possible.