Winding – tensioning – or guiding – Unidirectional winding and unwinding
Patent
1996-08-12
1998-03-17
Mansen, Michael
Winding, tensioning, or guiding
Unidirectional winding and unwinding
242 4701, 242150R, 66132R, 139452, B65H 5100, B65H 5922, D03D 4736, D04B 1548
Patent
active
057277460
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a thread feeder device for storing and feeding thread for textile machines having uneven rates of thread consumption, such as occurs in knitting or weaving machines that are capable of patterned knitting, Jacquard knitting, circular knitting, plating, and for example half plush and full plush weaving. The thread feeder device has a storage body which carries the thread without splippage and is actuated by a motor, in order to form a reserve thread winding. The thread is wound axially and tangentially, and according to requirements, it is unwound axially from said storage body between its front face, provided as a braking surface, and a complementary braking surface that rotates in the same rotational direction. The complementary braking surface is movable in an axial direction with respect to the braking surface of the storage body in order to vary the thread extraction tension.
Known devices of this type essentially have the drawback that although the thread extracted in an axial direction is prevented from lifting or flying away from the storage body by providing annular members located loosely on the storage body (e.g. metal ring, plastic ring, comb-shaped plastic ring, brushes, or the like), the known devices cannot provide the desired thread extraction tension (i.e., the tension applied to the thread which is supplied to a respective knitting machine) which is required for carrying out a flawless knitting process. In practice, the thread slides away from the storage body with a tension that is considerably lower than that with which it is fed to the storage body. To achieve a thread feed tensioning that is final and correct for knitting with the operating system of the knitting machine, an additional thread brake must accordingly be provided between the storage device and the knitting machine.
This solution for setting a correct tensioning of the thread fed to the knitting machine is not optimal, since the difficulties arising from thread braking are well-known: the cup-shaped brake, used in most cases, is difficult to adjust, and does not maintain the set value constantly (at least not for a long period of time). Furthermore, as thread enters the cup-shaped brake, fibers and particles of thread become deposited therein, thereby soiling the brake. Moreover, this known type of thread brake amplifies irregularities which occur when extracting the thread from the storage body and at the passage of the annular member or ring, constituted, e.g., by an annular comb or an annular brush. Unwanted flutter of the thread also often occurs, whereby individual needles may be unable to engage the thread; resulting in undesirable, irregular knitting, thereby causing the knitting machine to produce rejects.
In a conventional device of this type (Swiss patent publication 374 345) there is absolutely no annular arrangement that must retain the thread that exits axially from the storage body on the perimeter thereof. Instead, the thread, during extraction, upon operation of the knitting or weaving machine, forms a so-called balloon of thread, to achieve among other things the lowest possible thread tension; however, this is completely unusable, in practice at least in conventional knitting machines.
In another known device of this type (U.S. Pat. No. 3,225,446), a thread is wound tangentially on a winding body or storage body to form a reserve winding and is then extracted axially from said body. Although the thread, by means of an elastic ring, is prevented from flying away and from lifting in an uncontrolled manner away from the winding body, it is necessary to produce a preset thread extraction tension. In practice, this proposed solution is unusable, because the elastic ring is difficult to manufacture with the precision required in this case, especially with the necessary long-lasting constancy of precision, and furthermore, because each type and thickness of thread being used and each different thread extraction tension would require a special manufacture, for
REFERENCES:
patent: 3225446 (1965-12-01), Sarfati
patent: 4068807 (1978-01-01), Jacobsson
patent: 4079759 (1978-03-01), Riha et al.
patent: 4429723 (1984-02-01), Maroino
patent: 5489068 (1996-02-01), Vischiani
patent: 5546994 (1996-08-01), Sarfati
patent: 5553641 (1996-09-01), Zenoni
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