Textiles: spinning – twisting – and twining – Apparatus and processes – Transfer tail
Reexamination Certificate
2000-02-03
2001-09-18
Worrell, Danny (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Transfer tail
C057S303000
Reexamination Certificate
active
06289662
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for clamping an underwinding thread at a spindle of a ring-spinning machine whereby, associated with each spindle and below the cop or bobbin which is fitted thereon or may form thereon, a clamping device is provided.
The invention is particularly applicable to ring-spinning machines having a spindle rail provided with a multiplicity of spindles driven by respective drives, a ring rail movable up and down along the spindle of the row, respective travellers orbiting the bobbin or cop on the ring and guide means, e.g. a thread-guide eye above the cop or bobbin feeding the thread or yarn, usually from a drafting frame or from bobbins in a creel, to the ring-spinning station. The thread is twisted as it is applied to the cop and at the conclusion of winding, an underthread is provided which can be engaged, according to the invention, in a clamping device below the cop.
More particularly, the invention relates to the clamping device which can have a clamping ring which is axially fixed with respect to the cop and hence the spindle, a clamping sleeve which is axially movable with respect to the ring, the ring and spindle having frustoconical surfaces between which the underwinding thread is engaged. Preferably the underwinding thread loops around the spindle through less than 360° and the actuation device for the axially-movable sleeve is fixed on the ring-spinning machine.
BACKGROUND OF THE INVENTION
A prior art system of the aforedescribed type is found in EP 0 775 769 A1. In that system the underwinding thread is engaged between conical surfaces of a clamping ring and a clamping sleeve, the frustoconical surfaces being so constructed that they are self-locking when they are interengaged. In practice, however, soiling of the surfaces prevents reliable engagement of such a clamp.
OBJECTS OF THE INVENTION
It is the principal object of the present invention to improve the reliability of a system of the latter type and especially the clamping effectiveness.
Another object of the invention is to provide an apparatus for clamping an underwinding thread at the spindle of a ring-spinning machine whereby the clamping effectiveness is improved.
Still another object of the invention is to provide an apparatus for the purposes described which will be free from drawbacks of earlier clamping devices or roving machines and especially can result in an improvement in overall reliability.
Finally, it is an object of the invention to provide a method of operating a clamping device for a spindle of a ring-spinning machine that will ensure more reliable operation without a material increase in the cost thereof.
SUMMARY OF THE INVENTION
These objects are attained, in accordance with the present invention in an apparatus for clamping underwinding thread on a spindle of a ring-spinning machine which comprises:
below a cop fitted onto the spindle, an axially fixed clamping ring on the spindle, and an axially shiftable clamping sleeve on the spindle juxtaposed with the clamping ring, the clamping ring and the clamping sleeve having frustoconical clamping surfaces fitting one into another for engaging an underwinding thread between them upon axial shifting of the clamping sleeve toward the ring and releasing the underwinding thread upon axial shifting of the clamping sleeve away from the clamping ring, at least one of the surfaces being textured to effect increased retention of the underwinding thread upon clamping of the underwinding thread between the surfaces.
The method of the invention can comprise the steps of:
shifting an underwinding thread from a smaller diameter portion to a larger diameter portion of the clamping ring, thereby laying the underwinding thread between the surfaces of which at least one of the surfaces has been textured to effect increased retention of the underwinding thread upon clamping of the underwinding thread between the surfaces;
then clamping the underwinding thread between the surfaces by axially shifting the clamping sleeve toward the ring;
thereafter releasing the underwinding thread by axially shifting the clamping sleeve away from the ring; and
causing the underwinding thread to migrate upon release to a smaller diameter portion of the ring and centrifugally casting the released thread from the ring.
According to the invention, therefore, a clamping surface of the clamping ring and/or a clamping surface of the clamping sleeve are textured to have a greater coefficient of sliding friction against the thread. The texturing can be with the formation of grooves, teeth, zig-zags or meanders, milling or knurling as may be required. In many cases, the structuring can be so fine that it is practically only a roughening of the respective clamping surface. The effect which is utilized according to the invention can be attained with the texturing of only one of the two juxtaposed surfaces forming the clamp although texturing can be provided on both surfaces if desired.
In DE 298 21 679 U1 substantially planar clamping surfaces are moved together and are provided with a corrugated structure which, however, does not increase the friction retention of the threading but is designed to open the gap between two relatively rotatable members to permit release of the thread when the two members are so rotated. Here the corrugation acts as camming elements. According to a feature of the invention the texturing is provided on both the clamping sleeve and on the clamping ring and the two are interfitted, means being provided for securing the ring and sleeve against the relative axial displacement.
A further feature of the invention provides that at least one element of the clamping device is elastic so that the clamping sleeve and ring are held in the clamped or engaged position by spring force.
REFERENCES:
patent: 652725 (1900-06-01), Roney
patent: 2428081 (1947-09-01), Keight et al.
patent: 4617791 (1986-10-01), Lousberg
patent: 4796422 (1989-01-01), Odawara
patent: 5581989 (1996-12-01), Mann et al.
patent: 6085511 (2000-07-01), Dinkelmann et al.
patent: 2931209 (1980-02-01), None
patent: 42 21 676 (1994-01-01), None
patent: 43 37 100 (1995-04-01), None
patent: 19628826 (1998-01-01), None
patent: 292856 (1988-05-01), None
patent: 358032 (1989-08-01), None
patent: 587526 (1993-07-01), None
patent: 0 775 769 (1997-05-01), None
Darcis Gerhard
Dinkelmann Friedrich
Mann Peter
Dubno Herbert
Worrell Danny
Zinser Textilmaschinen GmbH
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