Weft feeder with adjustable-diameter drum for weaving looms, comprising an electromagnet unit controlling the weft thread release equipped with a quick-release device to adjust and fix its working position

Abstract

Weft feeder for weaving looms with thread coil separation comprising a winding group (W) to wind a weft thread onto a weft feeder drum (D), and an electromagnet unit (E) to control the movement of a stop pin (P) which prevents the weft thread from being released from said drum (D), wherein said electromagnet unit (E) is movable in a radial direction with respect to an axis of the weft feeder drum (D), along a pair of guide means (1, 2) provided in the base body (C) of said weft feeder and in said electromagnet unit (E), respectively, which consist of a pair of fixed guides (1) and a pair of mobile guides (2) symmetrically arranged with respect to an axial plane of the weft feeder passing therebetween and parallel thereto, each pair of guides having flat contact surfaces (1a, 2a) symmetrically inclined with respect to said axial plane of the weft feeder. A single locking/unlocking means (3, 4) having an axis parallel to the drum (D) axis stably fixes said electromagnet unit (E) in a predefined position and includes a pawl (3) housed in an undercut recess, provided between said pair of fixed guides (1) or in the weft feeder base body (C), and a tie-rod (4) connected to said pawl (3).

Claims

1. Weft feeder for weaving looms with thread coil separation, comprising a winding group (W) to wind a weft thread on a drum (D) of the weft feeder, and an electromagnet unit (E) to control the movement of a stop pin (P) which prevents the weft thread from being released from said drum (D), wherein said electromagnet unit (E) is movable in a radial direction with respect to an axis of the weft feeder drum (D), along guide means (1, 2) provided in the base body (C) of said weft feeder and in said electromagnet unit (E), respectively, and wherein said guide means (1, 2) comprises a pair of fixed guides (1) and a pair of mobile guides (2), both parallel to said radial direction and mutually coupled, at least one of said fixed guides (1) and a mobile guide (2) coupled therewith having flat contact surfaces (1a, 2a) inclined with respect to the weft feeder axis, characterized in that a single locking/unlocking means (3, 4) is also included, having an axis parallel to the drum (D) axis, for stably fixing said electromagnet unit (E) in a predefined position along said guide means (1, 2), so that upon tightening said single locking/unlocking means (3, 4) said guide means (1, 2) automatically cause centering of the electromagnet unit (E) with respect to the weft feeder axis, and prevent its rotation about the axis of said locking/unlocking means (3, 4), wherein said single locking/unlocking means (3, 4) includes a pawl (3) housed in an undercut recess provided between said pair of fixed guides (1) or in the weft feeder base body (C), and a tierod (4) connected to said pawl (3).

2. The weft feeder for weaving looms with thread coil separation as in claim 1, wherein said tierod (4) is a screw engaged with said pawl (3).

3. The weft feeder for weaving looms with thread coil separation as in claim 1, wherein said tierod (4) has a predetermined length and is connected to said pawl (3) at one end and to a quick-release locking/unlocking device at its opposite end.

4. The weft feeder for weaving looms with thread coil separation as in claim 3, wherein said quick-release locking/unlocking device includes a manually operated eccentric lever (6) hinged to the body (5) of said electromagnet unit.

5. The weft feeder for weaving looms with thread coil separation as in claim 3, wherein the predetermined length of said tierod (4) is adjustable during manufacturing or calibration.

6. The weft feeder for weaving looms with thread coil separation as in claim 5, further comprising an elastic means applying a preload force on said pawl (3) in the unlocked position of the locking/unlocking device.

7. The weft feeder for weaving looms with thread coil separation as in claim 6, wherein said elastic means comprises a small block (7), made of rubber or other elastic material, interposed between the eccentric lever (6) and an abutment surface of the electromagnet unit body (5).

8. The weft feeder for weaving looms with thread coil separation as in claim 6, wherein said preload force is high enough to prevent the electromagnet unit from moving under the sole action of its own weight, and wherein said preload force is low enough to allow the electromagnet unit movement along the pair of fixed guides (1) when a suitable force is applied thereon in such a direction.

9. The weft feeder for weaving looms with thread coil separation as in claim 1, wherein at least one between said pair of fixed guides (1) and said pair of mobile guides (2) is made of a self-lubricating material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further features and advantages of the weft feeder with adjustable-diameter drum comprising an electromagnet unit which controls the release of the weft thread according to the present invention will however become more evident from the following detailed description of a preferred embodiment of the same, given by mere way of non-limiting example and illustrated in the accompanying drawings, wherein:

[0017] FIG. 1 is an axial sectional view of a weft feeder incorporating the electromagnet unit of the present invention;

[0018] FIG. 2 is a partially exploded perspective view illustrating the adjustment and fixing device of the ELM unit working position according to the present invention; and

[0019] FIG. 3 is an exploded view of the ELM unit of FIG. 2 seen from an opposite direction.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] According to the present invention, in order to solve the problem highlighted above by means of a simply and quickly operable innovative solution, the ELM unit is fixed to the weft feeder base body C by means of an adjustment and fixing device consisting of a pair of fixed guides 1 provided in the weft feeder base body C, and a corresponding pair of mobile guides 2 provided in the ELM unit, said fixed guides 1 and mobile guides 2 being parallel and mutually coupled, and preferably symmetrically arranged with respect to an axial plane of the weft feeder passing therebetween and parallel thereto. The longitudinal direction of the fixed guides 1 and the mobile guides 2 is a radial direction with respect to the weft feeder drum D, a direction along which the ELM unit should in fact be able to move, during the adjustment step of its position, to adapt to a new diameter of the weft feeder drum D. The fixed guides 1 and/or the mobile guides 2 are preferably made of a self-lubricating material.

[0021] According to a main feature of the invention, and as clearly illustrated in FIGS. 2 and 3, the fixed guides 1 and the mobile guides 2 are sized in such a way that, when they are coupled together, the only surfaces in contact exclusively consist of flat contact surfaces 1a and 2a of the fixed guides 1 and the mobile guides 2, respectively. At least one of said flat contact surfaces 1a of the fixed guides 1 and the corresponding flat surface 2a of the mobile guides 2, and preferably both, are inclined with respect to the weft feeder axis. When both said flat contact surfaces 1a are inclined, they preferably are symmetrically arranged with respect to an axial plane passing therebetween and parallel thereto. The length of the inclined flat surfaces 1a, 2a is sufficient to ensure adjustable positioning of the ELM unit, parallelly to the longitudinal direction of said guides, for every diameter of the weft feeder.

[0022] The fixed guides 1 are mounted in their seat on the weft feeder base body C in such a way to form an undercut recess between them or in the same base body C, inside which a retaining pawl 3 of the whole ELM unit slides. The pawl 3 is then fixedby means of a tie-rod 4 of predetermined length, which length being adjustable during manufacturing or calibrationto a quick-release locking/unlocking device integral with the ELM unit body 5. The quick-release locking/unlocking device preferably consists of a manually operated eccentric lever 6, hinged to the ELM unit body 5 and apt to impart to the tie-rod 4 a sufficiently wide movement to cause the locking/unlocking of the ELM unit, upon rotation of the eccentric lever 6 of about 90. Thanks to this solution, the adjustment of the ELM unit position in a radial direction with respect to the weft feeder drum may be carried out extremely quickly and without use of additional manual tools.

[0023] When the eccentric lever 6 is in the open position, in fact, the ELM unit is free to move along the guides 1, 2 until being positioned at the desired height with respect to the weft feeder drum. Conversely, when the eccentric lever is in the closed position the ELM unit remains perfectly locked in the desired position. Furthermore, thanks to the particular mechanical solution used for the construction of the guides 1 and 2namely the use of contact walls consisting of inclined flat surfaces 1a and 2a having symmetrical inclination with respect to an axial plane of the weft feeder passing therebetweenthe ELM unit locking/unlocking device is imparted with a feature of automatic centering of the ELM unit position with respect to said axial plane, and is therefore able to ensure a constant repeatability of the position of the ELM unit with respect to the weft feeder base body C at each subsequent adjustment od said position, while also removing any possible rotary oscillation of the ELM unit about the axis of the locking/unlocking device consisting of the pawl 3 and the tie-rod 4.

[0024] Finally, the ELM unit quick-release locking/unlocking device according to the invention also allows a tie-rod 4 desired preload force to be set during manufacturing, by inserting a suitable elastic means, so that even in the unlocked position the ELM unit is held in position against the guides 1 by an adequate preload force. In the illustrated embodiment, said elastic means is a small block 7, made of rubber or other elastic material, interposed between the eccentric lever 6 and an abutment surface of the body 5, as clearly shown in FIGS. 2 and 3. In particular, said preload force shall be high enough to prevent the ELM unit from moving under the sole action of its own weight, and said preload force shall be low enough to allow the ELM unit movement along the guides 1, when a suitable force is manually applied thereon in such a direction. This solution ensures a greater precision of the position of the ELM unit, both because the ELM unit remains stationary in the adjustment positions set from time to time while the eccentric lever 6 is in the unlocked position, and because, when acting on said eccentric lever 6 to lock the ELM unit, no change in the ELM unit position occurs as a result of the pawl 3 tightening against the guides 1, precisely thanks to the preload force exerted by the small block 7, and therefore the ELM unit adjustment position and locking position are perfectly coincident.

[0025] From the preceding description it is evident how the present invention has fully achieved the intended objects. In fact, the pairs of guides with opposite inclined surfaces 1a and 2a allow to maintain the ELM unit lower plane constantly parallel to the reference sector of the weft feeder drum D, and the stop pin P correctly centered on the respective seat formed on the drum D.

[0026] Furthermore, thanks to the quick-release locking/unlocking device, the adjustment and fixing device of the invention may be quickly operated manually and therefore without use of tools.

[0027] Finally, thanks to the ability of setting a desired preload force to the locking/unlocking device when the same is in the unlocked position, the adjustment and fixing device of the invention maintains the ELM unit in a stable and unchanged working position even during the adjustment and fixing steps.

[0028] However, it is understood that the invention should not be considered as limited to the specific arrangements illustrated above, which are only exemplary embodiments thereof, but that different variants are possible, all within the reach of a skilled person in the art, without thereby departing from the scope of protection of the invention, which is only defined by the following claims.

REFERENCE LIST

[0029] Ahollow shaft [0030] Cbase body [0031] Ddrum [0032] Eelectromagnet unit (or ELM unit) [0033] Pstop pin [0034] Wwinding group [0035] 1fixed guides [0036] 1ainclined surfaces of fixed guides [0037] 2mobile guides [0038] 2ainclined surfaces of mobile guides [0039] 3pawl [0040] 4adjustable tie-rod [0041] 5ELM unit body [0042] 6eccentric lever [0043] 7small block made of rubber