JP6708405B2 - Weft insertion system for weaving machines - Google Patents

Description

The present invention relates to a projectile-type weaving machine, and more particularly to a weft thread insertion system in a projectile launching device.

As is known, projectile looms are such that the weft thread is a projectile, i.e., a tapered metal body of suitable mass and shape, and the end of the weft thread is secured to the projectile prior to firing, and thus to the fixed projectile. It is different from other types of loom due to the fact that it is inserted into the shed.

At the shed exit (which usually corresponds to the right hand side of the loom with respect to the position of the weaving machine), the projectile slows down and is stopped by the braking device and the weft yarns are unraveled, thus the projectile is the Return to the left hand side) through a suitable continuous transport system. On the launch side, a single subsequent projectile is also fixed to the desired weft thread and loaded into the shed which gradually brings the projectile to be fired again in front of the firing station.

Especially in view of the detectable advantages in weaving very high quality fabrics, such a loom type has some serious drawbacks.

First, there is the drawback of the mechanical type being directly connected to the high impact thrust imparted to the projectile. In particular, in addition to the problem determined by the impact the projectile receives from the projectile, there remains the complex problem of devising a suitable mechanism for producing a sufficiently strong but not overly invasive impact thrust.

GB 2,003,198 discloses a conventional launching device, in which the launching member, which is designed to make a strong contact with the rear end of the projectile, is attached to a lever controlled by a torsion bar which is periodically loaded through a cam mechanism. It is supported.

As can be easily considered, the cam load torsion bar system exhibits rather a rather critical mechanical configuration in terms of the stresses and loads applied and the opportunity to determine and control the law of motion of the projectile at the firing step. .

In fact, since the projectile is fired through the shed with very high impact acceleration and is not subsequently controlled by any control member, some typical weaving problems occur in projectile looms, especially the high initial stress of the weft thread. And there is substantially uncontrolled behavior of the projectile during all movements within the shed. In particular, when thrust impacts do not occur perfectly symmetrically on the projectile, the trajectory of the projectile is subject to lateral vibrations controlled by guides that slide the projectile but impair the effectiveness and regularity of firing.

EP-1591573 discloses another solution to the firing of a projectile, which is no longer a shock effect, and is brought to a maximum set speed through the advancing thrust provided by the insertion tape. The tape is controlled through a device similar to that already used in gripper operation on gripper looms, appropriately modified to produce the acceleration required to fire the projectile. The device comprises a gear meshing with a corresponding hole formed along an insertion tape, the gear being flexible to allow a curved arc of sufficient width in the gear, the gear comprising a locking arm, a connecting rod and a gear. It is controlled in alternating rotations by the main motion of the loom through a double desmodromic cam connected to the articulating squares which together form a tooth sector connected to a concentric pinion.

After the first firing step, the tape gradually slows back into and completes the weft insertion in the traditional manner of use in a projectile loom while the projectile continues to coast.

The technical solution disclosed by the 573 patent makes it possible, at least from a technical point of view, to overcome the abovementioned drawbacks of a projectile loom with a torsion bar launching device. In fact, the acceleration induced by such a launcher is slower than that of a conventional torsion bar device, and further, the projectile is always guided by tape into the interior of the first shed section, a known Get a more stable trajectory compared to that of the launch system.

However, despite these positive features, such a projectile firing system is not suitable for the weft insertion of other looms where the high inertia of the mechanical control of the gears mentioned above is found in the market. It has hitherto not been found as an effective industrial use due to the fact that it limits the operation of the reversing speed to a value that does not allow the construction of a projectile loom with speed (cycles per minute).

The present invention is therefore in the same technical field as disclosed in connection with the 573 patent, which is manifested by the above-mentioned known solutions with respect to the opportunity to reach a weft insertion speed which is competitive with the currently known types of looms on the market. An object of the present invention is to provide a weft insertion system in a projectile loom, which is free from the problems described above.

This object is achieved through a weft insertion system in a projectile loom having the features defined in claim 1. Other preferred features of such a weft thread insertion system are defined in the dependent claims.

Further features and advantages of the weft insertion system in a projectile weaving machine according to the invention are in any case from the following detailed description of its preferred embodiment, which is provided by way of non-limiting example only and is shown in the accompanying drawings. Will be clear.

It is a schematic perspective view of a projectile launching device. It is the whole schematic and partial sectional view of the all weft thread insertion system concerning the present invention. FIG. 3 is an angle diagram of the phase characteristics of the system of FIG. 2 for a weft insertion cycle.

According to the invention, in order to solve the above-identified problems, the projectile insertion member 1 is adapted to follow the progress of the rack R and its meshing, as a solution which is simple from a structural point of view and a solution for immediate application. Is composed of racks R which are driven in operation by a plurality of gears D arranged in series, each gear D being driven by a respective electric servomotor of the brushless electronic control type, for example. The rack R has a linear layout and is sufficiently rigid to transmit the thrust exerted by the gear D to the projectile 1 without undergoing significant deformation.

The number of motors M and their placement along the rack R determines the overall desired force, the maximum force effectively released by a single motor on the gear D which is simultaneously engaged in the corresponding cavity of the rack R, and , It can be changed freely depending on the space available near the loom. In particular, from this point of view, the motors M are arranged only on one side of the rack R and below it, as shown in FIG. 1, or on both sides or alternately or oppositely of the racks R, or in space. For optimal use and to reduce the required length of the rack R, they are arranged above and below the rack R in an offset arrangement with respect to each other and, in simultaneous engagement with the gear D, have the same number of cavities.

Due to the fact that the force required to obtain the desired acceleration of the rack R is split in several electric motors M, it is possible to use motors with very modest rotor dimensions, and thus each is very low. It can have a rotational inertia. The motor M with this low inertia can therefore achieve a very low reversal time and a high number of weft insertion cycles in the loom.

According to a preferred feature of the invention, the electronic control of the motors M is performed differently between one of the motors M, which is the main motor, and the rest of the motors M, which are trapped in the main motor. In particular, the electronic control is performed by controlling the main motor to the appropriate position in order to obtain the desired movement curve of the rack R within the weft insertion cycle. The torque imparted by the main motor as a result of such a law of motion is read and immediately copied to the remaining trapped motors, all acting at the same torque as the main motor.

According to a particular type of electronic control, the possibility of misalignment between different motors M is eliminated, in fact the position of the rack is controlled by only one main motor and all motors have the same torque in rack R. give. The thrust exhibited by the set of motors is instead easy if electronic control is a simple position control on all motors M, given the difficulty of getting perfect synchronization of such multiple position controls. , Which eliminates the possibility of stress changes in each tooth, and is completely evenly divided between all gears D engaging in each cavity of rack R.

FIG. 2 shows a weft thread insertion system as a whole, in addition to the above-mentioned launching device, as is known per se, a weft thread W, a launch path of a projectile 1 in which the weft thread of interest is pushed by a rack R. The weft yarn feeder F is supplied to the weft yarn selector P which is moved to the position. The weft thread W is clamped in flight by the projectile 1 by a method already known as a transport gripper of a gripper loom, and the projectile 1 is launched into the shed along a guide G by the action of the rack R.

When the velocity of the projectile 1 reaches the target value, the rack R begins to decelerate and stop, and the projectile passes through the gripper opening device 2 where it releases the weft thread W and the projectile braking device 3, the exit side of the loom. While it goes on by its inertia, it returns to the starting position. Thus, the projectile enters a suitable housing of the unloading device 4 (more clearly given the front view, in the lower part of FIG. 2), which unloads device 2 in the embodiment shown. It is equipped with two opposing housings and is actuated by a motor 5 which rotates the unloading device 4 by 180 degrees on an axis parallel to the trajectory of the projectile and brings the projectile into alignment with the projectile return device.

Here, such a return device is quite similar to that of a launch, but comprises a single motor M _R and respective gears D _R which actuate the rack R _{R so} that the projectile 1 can be returned. , Shoot them along the return rack 6 at a speed that is decelerated with respect to the forward speed, up to the launch side of the loom. The projectile 1 is now stopped by the braking device 7 and brought to the selective withdrawal position by the cursor retracting device 8 which returns the projectile 1 to the operating range of the loading device 9.

The loading device 9 and the relative actuating motor 10 have a layout, actuation and graphical representation which is quite similar to that described above for the unloading device 4, with the only difference being that of the projectile 1 of the loading device 9. The number of housings is doubled compared to that of the unloading device 4 (thus in the illustrated embodiment there are 4 housings offset by 90 degrees). This layout is because the time it takes a projectile to travel to the return track is about twice as long as the forward phase and one projector is moving along the return track 6 at the same time. It is possible to receive up to four projectiles in the loading device 9. As a result, in case of a machine shutdown, the loading device 9 should be able to accommodate all projectiles already sent to the return rack.

The preferred operating cycle of the weft thread insertion system, expressed at an angle adjusted to the weft thread insertion cycle (360°) and shown in FIG. 3, provides the following specific steps:
0°-Projector acceleration start 60°-Weft cut 65°-Rack enters the shed and starts deceleration 115°-Rack return start-Projector flight 300°-Projector arrival and rack relocation 360°-Projector brake And insert into unloading device

However, it is understood that the present invention should not be considered to be limited to the particular arrangements set forth above, which are merely exemplary embodiments, and depart from the scope of the invention solely defined by the following claims. Without regard, different modifications can be made, including all that would be considered by one of ordinary skill in the art.

Claims (8)

A weft insertion system in a projectile loom of the type in which the projectile (1) is launched into a shed by mechanical movement of thrust members with alternating periodic movements,
The thrust member is composed of a rack (R) whose movement is driven by a plurality of gears (D),
The weft insertion system, wherein each gear is driven by each electric servomotor (M) and is continuously arranged along the rack R and its meshing. The weft thread according to claim 1, characterized in that the rack (R) has a linear shape and is sufficiently rigid to transmit the thrust applied by the gear (D) to the projectile (1) without deformation. Insertion system. 3. The weft thread insertion system according to claim 2 , wherein the motors (M) are continuously arranged on one side or both sides of the rack (R) alternately or on opposite sides. 3. The weft insertion system according to claim 2 , wherein the motors (M) are arranged above and below the rack (R) alternately and on one or both sides thereof. Electronic control of the motor (M) is one of the motors for determining the desired motion curve of the rack (R) in the weft insertion cycle, and is applied to the position control of the motor which is considered to be the main motor. 3. The weft insertion system according to claim 2, further comprising: torque control of the remaining motor for adjusting the torque to the same value as the instantaneous torque value. Further, in the weft insertion direction (W), there are provided a loading device (9) and an unloading device (4) arranged on the upstream side and the downstream side of the loom, respectively,
Each comprises a housing for the projectile (1),
Each drive motor (10, 5) comprises a projectile (1) in which the housing of the projectile (1) connects the guide (G) of the projectile (1) or the unloading device (4) to the loading device (9). Provided for operating rotations of the loading device (9) and the unloading device (4) about an axis parallel to the projectile firing trajectory between preset angular positions in the same plane as the return rack of The weft thread insertion system according to any one of claims 1 to 5 . The loading device (9) has as many or more housings of projectiles (1) as the total number of projectiles moving simultaneously in the guide (G) and the return rack (6), The weft thread insertion system according to claim 6 . Projectile (1), through similar launchers main launcher is fired return the rack (6), the gears for actuating the single motor (M _R) and the rack (R _R) and (D _R) The weft insertion system according to claim 6 , which is provided.