Textiles: fiber preparation – Working – Drafting
Reexamination Certificate
2002-04-30
2003-05-27
Welch, Gary L (Department: 3765)
Textiles: fiber preparation
Working
Drafting
C019S150000, C019S236000
Reexamination Certificate
active
06568041
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a tube with suction slots for a unit for condensing a bundle of textile fibres drafted in a spinning machine.
The field of application of the present invention is that of spinning machines having a plurality of adjacent spinning stations in each of which there is a drafting unit associated with a condensing unit for treating a bundle of textile fibres, or roving, to be transformed into a twisted yarn.
For a better understanding of the prior art and of the problems inherent therein, a conventional condensing unit will be described first of all with reference to
FIGS. 1 and 2
of the appended drawings.
In
FIG. 1
, a bundle of textile fibres or roving
1
is supplied to a drafting unit, generally indicated
2
, comprising three pairs of rollers
3
and
4
,
5
and
6
,
7
and
8
, which pull the roving along at increasing linear velocities in order to thin it gradually. The roving output from the drafting unit
2
then goes to a condensing unit
10
located downstream of the drafting unit, before being sent for twisting.
The condensing unit
10
comprises a lower fixed tube
11
of circular cross-section, connected to a suction source (not shown), by means of a manifold
12
. As shown in
FIG. 2
, the tube
11
, which is common to several spinning stations located side by side, has, in each station, a narrow suction slot
15
arranged on the path of and in the direction of movement of the roving.
A plurality of freely rotatable cylindrical sleeves
16
are mounted along the tube
11
, there being one sleeve in the region of each spinning station and each sleeve having a central perforated portion
17
which extends around the entire circumference of the sleeve and covers the corresponding slot
15
with a large margin. Each sleeve
16
is driven so as to move around the tube
11
by a pressure roller
18
of elastomeric material which presses the roving against the perforated portion
17
of the filtering sleeve
16
. The pressure roller
18
is rotated by the last pressure roller
7
of the drafting unit
2
, by means of a belt transmission
19
.
As shown in
FIG. 2
, the outer surface of the fixed tube
11
is machined to form cylindrical recesses
13
which house locating rings
9
that perform the dual functions of:
keeping the sleeves
16
correctly positioned axially along the tube so that the central perforated portions
17
of the sleeves are located over on the respective suction slots
15
, and
limiting the area of the sliding contact surface between the sleeve
16
and the tube
11
to the narrow region of the recesses
13
.
An example of this prior art is described in EP-1106719-A, which is incorporated herein by reference.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a condensing unit of simple and inexpensive construction which, in particular, reduces the costs connected with the machining of the tube to render it suitable for housing the above-mentioned locating rings.
A further object of the invention is to provide a condensing unit which does not have the above-mentioned conventional locating rings.
These and other objects and advantages which will be understood further from the following description are achieved, according to the present invention, by a novel condensing unit.
REFERENCES:
patent: 4953349 (1990-09-01), Fehrer
patent: 6108873 (2000-08-01), Barauke
patent: 6263656 (2001-07-01), Barauke
patent: 6332244 (2001-12-01), Camozzi
patent: 6349533 (2002-02-01), Camozzi
patent: 1 106 719 (2001-06-01), None
Marzoli S.p.A.
Welch Gary L
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