Textiles: spinning – twisting – and twining – Apparatus and processes – Monitor and control
Reexamination Certificate
1999-07-23
2001-07-10
Lindsey, Rodney (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Monitor and control
C057S086000
Reexamination Certificate
active
06256972
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention concerns a device to automatically cut the slubbing of a yarn being worked as set forth in the main claim.
The invention is applied in the textile field and particularly, though not exclusively, in spinning machines.
The device according to the invention is suitable to quickly interrupt the feed of the slubbing, or spinning sliver, every time an anomalous event occurs in the working cycle and particularly when the yarn accidentally breaks due to the drawing operation.
In the following description particular reference will be made to a use of the invention in a spinning machine, but this application must not be taken as a limitation of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The state of the art includes spinning machines wherein a slubbing, taken from a reel or similar, is subjected to drawing and torsion to achieve a yarn which is progressively wound into coils on a cop keyed onto a rotating spindle.
In a ring-type spinning machine, for example, the slubbing is drawn by a drawing assembly comprising at least two pairs of counter-rotating rollers through which the slubbing is made to pass; by making the pairs of rollers arranged upstream rotate at a speed less than that of the pairs of rollers arranged downstream, a defined value of drawing is obtained.
As the yarn is wound onto the cop, it often happens that the yarn breaks downstream of the drawing assembly, which causes the yarn to wind around the outlet rollers of the drawing assembly.
Given the high speeds of feed which are at present achieved by textile machines, if this disadvantage is not immediately identified by the workers, it can lead to quite a considerable mass of yarn being wound onto the drawing rollers, which results in a considerable quantity of material being discarded, and also, possibly, the mechanical organs may break.
Moreover, this mass of yarn is usually removed by using very sharp blades, which are dangerous for the workers; this operation also requires a long time, which considerably reduces the productivity of the machine. Using such blades, moreover, may often lead to the surface of the rollers of the drawing assembly being damaged, as it is usually covered with cloth, skin, rubber or other synthetic materials, which necessarily requires the damaged rollers to be replaced, to avoid repercussions on the final quality of the yarn produced.
In some cases, moreover, the free end of the broken yarn may wind around an adjacent yarn being worked, and this is damaged too.
To prevent these problems, various devices have been proposed suitable to interrupt the feed of the slubbing every time that there is an accidental breakage of the yarn downstream of the drawing assembly.
Such devices comprise a sensor located downstream of the drawing assembly suitable to detect the presence of the passing yarn and to signal when it is absent by activating cutting means located immediately upstream of the said drawing assembly. The intervention of the cutting means prevents the slubbing which is still wound on the reel from being able to wind onto the drawing rollers or the free end of the yarn from interfering with other functional organs of the spinning machine or with the other yarns being worked.
The state of the art includes a device with a first disk with which a helical torsion spring is coaxially associated, suitable to be charged to make the disk rotate by a defined angle.
A blade is associated tangentially to the disk and is suitable to cooperate with a fixed surface, located at a defined distance from the disk; the slubbing is made to pass between the blade and the fixed surface.
The disk is suitable to selectively assume an inactive position wherein the blade is distanced from the slubbing or a working position wherein the blade abuts on the surface and cuts the slubbing.
The inactive position of the disk is maintained by a second, rotary disk having a peripheral shaping suitable to temporarily accommodate a small peg orthogonally associated with the first disk.
The second disk can selectively assume a clamped position wherein it clamps the peg, and hence the first disk, or an unclamped position wherein it releases the peg, allowing the first disk to rotate to move to the working position.
The second disk is held in the clamped position by a retaining tooth, which can be activated by an electromagnet, suitable to cooperate with a mating groove arranged radially on the second disk.
By activating the electromagnet it is possible to make the retaining tooth retreat, and hence to release the second disk and, consequently, to release the first disk which moves to the working position allowing the blade to cut the slubbing.
When the electromagnet is de-activated, the retaining tooth returns to its original position, thanks to an extension spring.
Even if this device may be considered efficient from an operational point of view, it consists of a high number of components and therefore has high costs, it takes a long time and is difficult to assemble. Moreover, it has some components, for example, the springs, which are subject to wear or may easily break.
The present Applicant has devised and embodied this invention to overcome these shortcomings and to obtain other advantages as will be shown hereafter.
SUMMARY OF THE INVENTION
The invention is set forth and characterised in the main claim, while the dependent claims describe other characteristics of the main embodiment.
The purpose of the invention is to provide a device suitable to automatically cut the slubbing, or sliver, of a yarn being worked, every time an anomalous event occurs which could compromise the functioning of the machine, the quality of production or the safety of the workers.
To be more exact, the device according to the invention is suitable to intervene downstream of the support which feeds the slubbing when there is an accidental breakage of the yarn in a defined zone of the working travel.
A further purpose is to achieve a device with a limited number of components, economical, functional and which does not easily suffer from malfunctions.
It is also a purpose of the invention to provide a device suitable to vary its configuration to adapt to any type of spinning machine without needing to intervene on the structure of the latter.
The device according to the invention comprises, in its essential parts, sensor means suitable to signal the presence or absence of the yarn and a cutting assembly functionally associated with the sensor means.
According to the invention, the cutting assembly is activated at least when the sensor means do not detect the presence of the yarn.
The cutting assembly comprises, in its essential parts, a support which can be associated with the textile machine, a blade and an electromagnet suitable to cooperate with the blade.
The blade is suitable to selectively assume an inactive position of non-interference with the slubbing passing through, or a cutting position in which it abuts against a contrasting surface cutting the slubbing interposed between the blade and the said surface.
According to one characteristic of the invention, the blade has at least a defined magnetised zone suitable to be constrained to the core of the electromagnet, when the latter is in its de-energised condition, assuming the inactive position.
When the electromagnet is energised, a magnetic field is induced on the core suitable to take the blade to the cutting position against the action of the magnetised zone.
In the preferential embodiment of the invention, the transition from the inactive position to the cutting position takes place substantially due to the force of gravity; this allows to reduce to a minimum the number of components of the device, eliminating the mechanical organs such as levers, springs, disks or otherwise, which are needed in conventional devices for the automatic activation of the blade.
REFERENCES:
patent: 539869 (1895-05-01), Holland et al.
patent: 3322013 (1967-05-01), Felix
patent: 3751896 (1973-08-01), Ford
patent: 4023341 (1977-05-01), Saino et al.
patent:
Akin Gump Strauss Hauer & Feld L.L.P.
Atex SpA
Lindsey Rodney
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