Weft feeder with drum of adjustable diameter for weaving machine with electromagnet unit for controlling weft release with quick release device for adjusting and fixing operating position

Abstract

To provide a weft feeder equipped with an adjustable diameter drum capable of quickly adjusting the operating position of an ELM unit and fixing the ELM unit with high accuracy and good reproducibility.SOLUTION: A weft feeder comprises a weft feeder drum D, a winding group W, and an electromagnet unit E for controlling the movement of a stop pin P. The electromagnet unit is movable in the radial direction of the drum axis along a pair of guide means. The guide means is consisting of a pair fixed and moving guides, and arranged symmetrically to the axial plane of the weft feeder. The axial plane passes between the guides, and is parallel to the fixed and moving guides. Each pair of guides has a flat contact surface inclined symmetrically to the axial plane of the weft feeder. A single locking / unlocking means 3 and 4 having an axis parallel to the drum axis comprises: a pawl 3 which stably fixes the electromagnet unit in a predetermined position, is housed in an undercut recess, and is disposed between the pair of fixed guides or in a base body C of the weft feeder; and a tie rod 4 connected to the pawl.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a new weft supply device for weaving machines, in particular for air-jet weaving machines and water-jet weaving machines. The weft supply device includes an electromagnet unit for controlling the release of the weft in addition to the normal functions already provided by known types of weft supply devices currently available, and is provided with a quick release adjustment device for obtaining a pre-adjustment of its working position.

Background Art

[0002] As is well known, the weft supply device is a weft supply device interposed between the weaving machine and the yarn package. The weft supply device forms a reserve of weft that is axially drawn from the drum of the weft supply device at a variable speed during the insertion operation into the shed in a later process, so that the weft can be wound continuously on a cylindrical drum at a speed as constant as possible - clockwise or counterclockwise depending on the characteristics of the yarn - and continuously accumulated to supply the weft to the weaving machine. As a result, the weft supply device does not generate tension peaks in the weft that could impair the soundness of the weft and the quality of the fabric.

[0003] The weft supply device is a device that has been used in weaving factories for many years. Along with years of evolution, in addition to the above-mentioned basic functions, the weft supply device has a function of confirming the presence of the weft at specific important points of the weft supply device, a function of adjusting the amount of weft accumulated in reserve and the distance between individual winding bodies, a function of decelerating the weft sent out to suppress the dynamic effects caused by rapid retraction acceleration, and finally an additional function that enables control of releasing the weft at a predetermined length for insertion into the shed formed by the warp threads.

[0004] To enable the above functions to be executed correctly, the weft supply device (Figure 1) is provided with an optical unit and an electromagnet unit E (hereinafter also referred to as the "ELM unit"). The optical unit includes one or more optical sensors and retroactively controls the weft supply device electric engine that controls the rotation of the hollow shaft A (that is, the accumulation of new winding bodies of the weft on the drum D), thereby monitoring the weft winding on the drum D by the winding group W that is integral with the weft supply device hollow shaft A, and executing the function of counting the number of winding bodies released from the drum D to the weft insertion device. The ELM unit controls the linear movement of the weft stop pin P between a forward position that prevents the weft from being released from the drum of the weft supply device when the free end of the weft stop pin P is inserted into a corresponding seat provided on the drum D, and a retracted position that enables the weft to be released. By the combination of the optical unit and the ELM unit, the weft is drawn out from the loom by a length corresponding to the desired length of the weft inserted into a predetermined number of winding body-clearances.

[0005] To operate the optical unit and the ELM unit correctly, the distance between the ELM unit and the drum D must be determined with such accuracy that the sensor of the optical unit can correctly detect the passage of the weft and the stop pin P of the ELM unit can enter sufficiently into the corresponding seat of the drum D to hold the weft winding body on the drum D.

[0006] In the weft supply device with an adjustable drum diameter targeted by the present invention, in order to change the length of the weft portion supplied to the loom, the working diameter of the drum D may be changed for each process. In that case, it is necessary to adjust the position of the entire ELM unit directly attached to the weft supply device base body C as quickly and stably as possible, track the new position of the drum D, and then stably maintain a predetermined optimal working distance.

[0007] At present, the ELM unit is provided on the base body C of the weft supply device and on the ELM unit itself, respectively, and slides along a pair of guide means having a radial direction with respect to the weft supply device drum D. Subsequently, the ELM unit is fixed at a desired position by a claw that slides within the guide means provided on the base body. The claw is actually fixed to the ELM unit through engagement with a screw passing through the ELM unit in a direction parallel to the axis of the drum D, so by acting on the screw to bias the claw against the guide means, it can be locked in a predetermined position. In this way, the sliding of the ELM unit can be stopped at any desired position along the guide means.

[0008] However, the above-described ELM unit support and locking device has two main drawbacks. - There is inherent play in the screw / claw assembly, and the position of the ELM unit cannot be accurately and repeatedly adjusted. In particular, since the ELM unit remains partially free to swing around the axis of the screw / claw assembly, it is difficult to maintain the lower surface of the ELM unit where the optical sensor and the stop pin P are arranged in an exactly parallel state with the reference portion of the weft supply device drum D, and it is also difficult to maintain the exact centering between the stop pin P and each sheet provided on the drum D. - Due to the loosening of the screw / claw assembly that must be done before the adjustment step of the ELM unit position, the ELM unit ends up at a position slightly different from the working position in the adjustment step. This means that during the step of tightening the claw, the ELM unit is set in a slightly displaced state with respect to the last set adjustment position. Therefore, in order to accurately determine the desired final position of the ELM unit, it is necessary to repeat the adjustment and fixing procedures. Summary of the Invention Problems to be Solved by the Invention

[0009] Accordingly, the technical problem to be solved by the present invention is to provide a weft supply device with an adjustable diameter drum, in which the working position of the ELM unit is adjusted quickly, and the ELM unit can be fixed at such a position with high pre-accuracy and reproducibility.

[0010] In the context of this technical problem, a first object of the present invention is to provide an ELM unit with an adjustment and fixing device for its working position, which is suitable for ensuring a certain parallelism between the lower surface of the ELM unit and the reference part of the weft supply device drum D, and for ensuring the accurate centering between the stop pin P and the corresponding seat provided on the drum D.

[0011] A second object of the present invention is to provide an ELM unit in which the adjustment and fixing device can be operated quickly, preferably without using tools.

[0012] Finally, a third object of the present invention is to provide an ELM unit in which the adjustment and fixing device maintains a stable and invariant working position of the ELM unit even during the adjustment and fixing operations.

Means for Solving the Problem

[0013] This problem is solved by a weft supply device with a drum of adjustable diameter for a fabric, including a weft supply device electromagnet unit for controlling the release of the weft, having the features defined in independent claim 1, and these objects are achieved. Other preferred features of such a weft supply device are defined in the dependent claims.

Brief Description of the Drawings

[0014] However, further features and advantages of the weft supply device with an adjustable diameter drum, including an electromagnet unit for controlling the release of the weft according to the present invention, will become more apparent from the following detailed description of a preferred embodiment of the weft supply device. The preferred embodiment of the weft supply device is given as a mere non-limiting example and is illustrated in the accompanying drawings.

Figure 1

Figure 2

Figure 3

[0015] According to the present invention, in order to solve the above - emphasized problems by an innovative solution means that can be operated simply and quickly, the ELM unit is fixed to the weft supply device base body C by an adjustment and fixing device consisting of a pair of fixed guides 1 provided on the weft supply device base body C and a pair of corresponding moving guides provided in the ELM unit. The fixed guide 1 and the moving guide 2 are parallel and coupled to each other, and are preferably arranged symmetrically with respect to the axial plane of the weft supply device passing therebetween and being parallel. The longitudinal direction of the fixed guide 1 and the moving guide 2 is the radial direction with respect to the weft supply device drum D, and actually, during the step of adjusting the position of the ELM unit, it is a direction in which the ELM unit can move to adapt to the new diameter of the weft supply device drum D. The fixed guide 1 and / or the moving guide 2 are preferably made of a self - lubricating material.

[0016] According to the main features of the present invention, and as clearly shown in FIGS. 2 and 3, when the fixed guide 1 and the moving guide 2 are coupled, their sizes are determined such that the only surfaces in contact are only the flat contact surfaces 1a and 2a of the fixed guide 1 and the moving guide 2, respectively. At least one - preferably both - of the flat contact surface 1a of the fixed guide 1 and the corresponding flat surface 2a of the moving guide 2 are inclined with respect to the weft supply device axis. When both of the flat contact surfaces 1a are inclined, both of the flat contact surfaces 1a are preferably arranged symmetrically with respect to the axial plane passing therebetween and being parallel. The length of the inclined flat surfaces 1a, 2a is sufficient to ensure adjustable positioning of the ELM unit parallel to the longitudinal direction of the guides for any diameter of the weft supply device.

[0017] The plurality of fixed guides 1 are mounted in a sheet on the base body C of the weft supply device so as to form undercut recesses between the plurality of fixed guides 1 or within the base body C of the weft supply device. Inside the recess, the holding claws 3 of the entire ELM unit slide. These claws 3 are fixed, during manufacture or calibration, by tie rods 4 of a predetermined length, to a quick-release lock / lock release device integral with the ELM unit body 5. This quick-release lock / lock release device preferably consists of a manually operated eccentric lever 6 hinged to the ELM unit body 5, and when the eccentric lever 6 rotates by approximately 90°, it gives the tie rod 4 a movement of sufficient width to cause locking / lock release of the ELM unit. Thanks to this solution, the position of the ELM unit radially with respect to the weft supply device drum can be adjusted extremely quickly without using additional manual tools.

[0018] When the eccentric lever 6 is in the open position, in fact, the ELM unit can move freely along the guides 1, 2 until it is positioned at the desired height with respect to the weft supply device drum. Conversely, when the eccentric lever is in the closed position, the ELM unit remains completely locked in the desired position. Furthermore, thanks to a special mechanical solution used in the construction of the guides 1 and 2 - namely, the use of contact walls consisting of inclined flat surfaces 1a and 2a having an inclination symmetrical with respect to the axial plane of the weft supply device passing between the guide 1 and the guide 2 - the lock / lock release device of the ELM unit is given the function of automatically centering the position of the ELM unit with respect to the said axial plane. Thus, a certain reproducibility of the position of the ELM unit with respect to the body C of the base of the weft supply device can be ensured, and the possibility of rotational vibration of the ELM unit about the axis of the lock / lock release device consisting of the claw 3 and the tie rod 4 can be eliminated.

[0019] Finally, the quick release lock / unlock device of the ELM unit according to the present invention also enables setting of a desired preloading force on the tie rod 4 during manufacture by inserting appropriate elastic means, whereby also in the unlocked position the ELM unit is held in a predetermined position against the guide 1 by an appropriate preloading force. In the illustrated embodiment, the elastic means is a small block 7 made of rubber or other elastic material, which is arranged between the joint surface of the eccentric lever 6 and the body 5, as clearly shown in FIGS. 2 and 3. In particular, the preloading force must be high enough to prevent the ELM unit from moving under the action of its own weight only, and the preloading force must be low enough to enable the ELM unit to move along the guide 1 when an appropriate force is manually applied to the ELM unit in the direction along the guide 1. This solution guarantees a higher positional accuracy of the ELM unit. The reason is that while the eccentric lever 6 is in the unlocked position, the ELM unit remains stationary at the adjustment position set at any time, and when the eccentric lever 6 is actuated to lock the ELM unit, the preloading force exerted by the small block 7 causes the pawl 3 to be clamped against the guide 1, resulting in no change in the position of the ELM unit, so that the adjustment position and the locked position of the ELM unit exactly coincide.

[0020] From the foregoing description, it is clear how the present invention has completely achieved the intended purpose. In fact, the pair of guides having the opposing inclined surfaces 1a, 2a always keeps the lower plane of the ELM unit parallel to the reference portion of the weft supply device drum D, and the stop pins P are accurately arranged at the center of each sheet formed on the drum D.

[0021] Furthermore, thanks to the quick lock / unlock device, the adjustment fixing device of the present invention can be quickly and manually operated without using tools.

[0022] Finally, since the desired preload force can be set on the locking / unlocking device when it is in the unlocked position, the adjusting and fixing device of the present invention keeps the ELM unit in a stable and unchanging working position even during the adjusting and fixing steps.

[0023] However, the present invention should not be considered as being limited to the particular arrangements exemplified above, which are merely exemplary embodiments thereof, but rather it is understood that different modifications are possible within the reach of a person skilled in the art without departing from the scope of protection of the present invention, which is defined solely by the following claims. [Explanation of symbols]

[0024] A Hollow shaft C Base body Drum E Electromagnet unit (or ELM unit) P Stop pin W Winding group 1 Fixed guide 1a Inclined surface of fixed guide 2. Travel Guide 2a Inclined surface of moving guide 3 Claws 4 Adjustable tie rods 5 ELM unit body 6 Eccentric Lever 7. Small rubber blocks

Claims

1. A weft yarn supply device for a loom having a bobbin winding body separation part, a winding group of the weft yarn supply device that winds the weft yarn around a weft yarn supply device drum, an electromagnet unit that controls the movement of a stop pin that prevents the weft yarn from being released from the drum, comprising: the electromagnet unit is movable in a radial direction with respect to the axis of the weft yarn supply device drum along a base body of the weft yarn supply device and a pair of guide means provided in the electromagnet unit, the pair of guide means is composed of a pair of fixed guides and a pair of movable guides, both the pair of fixed guides and the pair of movable guides are parallel to each other in the radial direction and are coupled to each other, at least one of the pair of fixed guides and a movable guide coupled to at least one of the pair of fixed guides has a flat contact surface that is inclined with respect to the axis of the weft yarn supply device, also included is a single lock / unlock means having an axis parallel to the axis of the drum, the single lock / unlock means, by stably fixing the electromagnet unit in a predetermined position, when tightening the single lock / unlock means, the pair of guide means automatically centers the electromagnet unit with respect to the axis of the weft yarn supply device and prevents rotation of the electromagnet unit around the axis of the single lock / unlock means, the single lock / unlock means has a claw housed in a recess between the pair of fixed guides or in an undercut recess provided in the base body of the weft yarn supply device, and a tie rod connected to the claw, A weft yarn supply device characterized by the above.

2. A weft yarn supply device for a loom having a bobbin winding body separation part according to claim 1, wherein the tie rod is a screw that engages with the claw.

3. A weft yarn supply device for a loom having a bobbin winding body separation part according to claim 1, wherein the tie rod has a predetermined length, is connected to the claw at one end, and is connected to a quick release lock / unlock device at the end opposite to the one end.

4. A weft yarn supply device for a loom having a bobbin winding body separation part according to claim 3, wherein the quick release lock / unlock device has a manually operated eccentric lever pivotally connected to the main body of the electromagnet unit.

5. A weft yarn supply device for a loom having a bobbin separating part according to claim 3 or 4, wherein the predetermined length of the tie rod is adjustable during manufacturing or calibration.

6. A weft yarn supply device for a loom having a bobbin separating part according to claim 5, further comprising elastic means for applying a preloading force to the claw at the unlocking position of the lock / unlock device.

7. A weft yarn supply device for a loom having a bobbin separating part according to claim 6, wherein the elastic means comprises a small block made of rubber or other elastic material interposed between the eccentric lever and the adjacent surface of the main body of the electromagnet unit.

8. A weft yarn supply device for a loom having a bobbin separating part according to claim 6, wherein the preloading force is large enough to prevent the electromagnet unit from moving under the sole action of its weight, and the preloading force is small enough to allow movement of the electromagnet unit along the pair of fixed guides when an appropriate force is applied to the electromagnet unit in such a direction. Weft yarn supply device.

9. A weft yarn supply device for a loom having a bobbin separating part according to any one of claims 1 to 8, wherein at least one of the pair of fixed guides and the pair of moving guides is made of a self-lubricating material.

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