Information
-
Patent Grant
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6170126
-
Patent Number
6,170,126
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Date Filed
Tuesday, July 27, 199925 years ago
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Date Issued
Tuesday, January 9, 200123 years ago
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Inventors
-
Original Assignees
-
Examiners
- Calvert; John J.
- Welch; Gary L.
Agents
- Evenson, McKeown, Edwards & Lenahan, P.L.L.C.
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CPC
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US Classifications
Field of Search
US
- 019 150
- 019 236
- 019 237
- 019 238
- 019 239
- 019 240
- 019 241
- 019 242
- 019 243
- 019 244
- 019 245
- 019 246
- 019 247
- 019 248
- 019 249
- 019 250
- 019 252
- 019 263
- 019 286
- 019 287
- 019 288
- 019 304
- 019 305
- 019 306
- 019 307
- 019 308
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International Classifications
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Abstract
A transport belt of a ring spinning machine for transporting a fiber strand to be condensed over a suction slit of a condensing zone is provided with a perforation or perforations for a suction air stream which suctions the fiber strand. The transport belt comprises a nonperforated area which permits a friction drive, and also an effective area containing the perforation, the width of the effective area being larger than the width of the suction slit. For example, the transport belt comprises a skeleton belt forming a supporting structure with a close-meshed woven fabric applied thereto.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
This application claims the priority of German application 198 37 179.9, filed Aug. 17, 1998, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a transport belt for transporting a fiber strand to be condensed over a suction slit of a condensing zone, said belt having a perforation for a suction air stream which sucks the fiber strand.
In U.S. Pat. No. 5,600,872 a transport belt of this type is described, which is designed like a drafting apron, but made of a material which has a greater elastisicity than is usual in the case of drafting aprons. The transport belt comprises centrical holes arranged in travel direction, through which holes the suction air stream enters. The size of the perforations determines to what degree the fiber strand is bundled transversely to the transport direction in the condensing zone. The transport belt is guided during operation over a suction slit, which extends in transport direction and which is essentially wider than the perforation.
The condensing of an already drafted, yet still spinning twist-free fiber strand serves the purpose of rolling outwardly projecting edge fibers around the core strand, so that a better material utilization is permitted and that the fiber strand is less hairy before being imparted a spinning twist. This results in a smoother and more tear resistant yarn.
It has been shown that it is not favorable when the clearance of the perforation holes alone determines the degree of condensing. The diameter of the holes would have to be so large that the air entering though the perforations would become inhomogenous.
It is an object of the present invention to make the condensing effect not exclusively dependant on the clearance of the perforation, but rather to chose a perforation with which a homogenous as possible suction air stream can be achieved.
This object has been achieved in accordance with the present invention in that the transport belt comprises a non-perforated area which permits a friction drive, and an effective area containing the perforation, which effective area is wider than the width of the suction slit.
In contrast to prior art, the clearance of the perforation holes no longer determine the condensing effect, but rather the suction slit located under the transport belt. The width of the suction slit is somewhat wider than the width of the condensed fiber strand. The effective width of the perforation is in contrast significantly wider, namely so wide that the suction slit can, if required, be arranged under the perforation slightly transversely to the transport direction, in order that the fiber strand to be condensed is imparted an additional, slight false twist. In the case of such an embodiment the perforation can be so close-meshed that a completely homogenous suction air stream arises.
The transport belt can consist of a flexible apron looped around a drive roller, which apron comprises a plurality of centrical rows of holes. A thin steel belt of, for example, 0.4 mm thickness can be provided, which comprises a centrical perforation produced by means of etching. Particularly advantageous is, however, a skeleton type supporting structure for a transport belt, on which only a very thin perforated tape is applied in the central area. This centrical placed perforated tape can consist of a particularly thin and close-meshed woven or knitted fabric.
In a variation of the embodiment according to the present invention, the perforated tape is welded or adhered to the skeleton-like supporting structure. Alternatively, the perforated tape can be applied to the skeleton belt in an interchangeable way.
It is important that the perforation is as closely meshed as possible, while on the other hand the perforated area should be significantly wider than the fiber strand to be condensed. The perforation serves only for the generating of a suction air stream, which effects the pneumatic condensing. The degree of condensing is however determined by the suction slit located under the transport belt.
BRIEF DESCRIPTION OF THE DRAWINGS
These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawings wherein:
FIG. 1
is a part sectional side view of a transport belt according to the present invention;
FIG. 2
is a view in direction of arrow II onto
FIG. 1
;
FIG. 3
is a schematic sectional view of another embodiment of a transport belt according to the present invention, the design of said transport belt permitting the extension of the suction slit up to a twist block limiting the spinning twist;
FIG. 4
is a view in the direction of arrow IV of
FIG. 3
onto the condensing zone;
FIG. 5
is a sectional view along the sectional surface V—V of
FIG. 4 through a
greatly enlarged transport belt according to the present invention;
FIG. 6
is a view onto a transport belt in the form of a steel belt having centrical perforations produced by etching; and
FIG. 7
is a view onto a so-called skeleton belt, which serves as a supporting structure for a close-meshed woven sieve belt.
DETAILED DESCRIPTION OF THE DRAWINGS
In the embodiment of the present invention according to
FIGS. 1 and 2
, only the area of a front roller pair
2
of a drafting assembly
1
of a ring spinning machine is shown. The front roller pair
2
comprises in a known way a driven bottom cylinder
3
which extends in machine longitudinal direction, on which bottom cylinder
3
one top roller
4
per spinning station is flexibly pressed. Further, an apron pair of the drafting assembly
1
can be recognized, which apron pair is arranged upstream of the front roller pair
2
, and which apron pair consists of a bottom apron
5
and an upper apron
6
.
In the drafting assembly
1
a sliver or roving
7
is drafted in transport direction A to the desired degree of fineness. Downstream of the front roller pair
2
a finished drafted apart from a slight subsequent draft-fiber strand
8
exists, which is guided through a condensing zone
9
. In the condensing zone
9
, still outwardly projecting edge fibers are to be rolled around the core strand under a light tension draft, so that the fiber strand
8
is bundled, becomes less hairy and is overall smoother and more tear resistant after a spinning twist has been imparted.
A transport belt
10
serves to transport the fiber strand
8
through the condensing zone
9
, which transport belt
10
is provided centrically with a perforation
11
. The perforation
11
serves to suction the fiber strand
8
to the transport belt
10
by means of a suction air stream.
The perforation
11
is limited to a centrical effective area
12
of the transport belt
10
. This effective area
12
is laterally defined by a non-perforated area
13
,
14
, which has an exclusively reinforcing function and which supports the friction drive of the transport belt
10
.
A delivery roller pair
15
ends the condensing zone
9
on its exit side, which delivery roller pair
15
comprises a driven bottom roller
16
and a top roller
17
pressed thereon. The top roller
17
is driven by the bottom roller
16
and drives in turn the transport belt
10
which is looped around the top roller
17
by means of friction.
The delivery roller-pair
15
forms a twist block to the onset of spinning twist in the yarn
18
to be spun, which yarn
18
is guided in delivery direction B to a ring spindle. The condensing zone
9
is thus free of any spinning twist and is essentially free of draft.
The transport belt
10
comprises in its effective area
12
a plurality of centrical rows
19
of holes, whereby the effective area
12
is in its entirety so wide, that a suction slit
20
located thereunder is completely covered. The fiber strand
8
is transported by means of the transport belt
10
over the suction slit
20
, which is disposed slightly transversely to the transport direction A. The suction slit
20
is itself somewhat wider than the finished drafted fiber strand
8
.
The transport belt
10
slides between the front roller pair
2
and the delivery roller pair
15
over a hollow profile
21
of the suction device. The suction slit
20
, disposed slightly transversely, is directed towards the transport belt
10
, so that under the effect of the inclination of the suction slit
20
and the transport direction of the transport belt
10
, the fiber strand
8
is imparted a slight false twist during condensing.
The hollow profile
21
is connected to a suction supply
22
, which leads to a vacuum source (not shown).
Deviating from the above described prior art, the diameter of the holes of the perforation
12
no longer determines the degree of condensing, but rather the position and the dimensions of the suction slit
20
do. The perforation
12
should be as close-meshed as possible and ensure a homogenous suction air stream.
In the Figures described below the same reference numbers will be used as before, insofar as components having identical functions are involved. A repeat description is therefore omitted.
The embodiment of the present invention according to
FIGS. 3 and 4
differs from the previous design essentially in that now a transport belt
23
is provided, which is no longer looped around a transport roller. In place of the delivery roller pair
15
as shown in
FIGS. 1 and 2
, a nipping roller
24
is provided in the embodiment according to FIGS.
3
-and
4
. The transport belt
23
runs around a hollow profile
21
, which may extend over a plurality of spinning stations. The outer contour of the hollow profile
21
is in the form of a sliding surface for the transport belt
23
. The nipping roller
24
presses the fiber strand
8
to be condensed against the transport belt
23
and this in turn on the hollow profile
21
, which is part of a suction device. The pressure of the nipping roller
24
is effected along a nipping line
26
, which here also is effective as a twist block against the spinning twist in the yarn
18
.
The condensing zone
9
is located now between the front roller pair
2
of the drafting assembly
1
and the nipping line
26
. This design has the advantage that the suction slit
25
applied to the hollow profile
21
can now be guided up to the nipping line
26
. The transport belt
23
itself is driven by means of friction by the nipping roller
24
, which in turn is driven by means of a drive belt
29
by the top roller
4
.
In the embodiment according to the present invention as shown in
FIGS. 3 and 4
, the perforation
11
is provided only over an effective area
12
in the centrical area of the transport belt
23
. The width of the effective area
12
is so chosen, that it completely covers the suction slit
25
. Thus the diagonal, the width and the length of the suction slit
25
determine here also the condensing effect, while the perforation
11
of the transport belt
23
primarily ensures as homogenous a suction air stream as possible.
The transport belt
23
has, as can be seen in particular in the enlarged representation in
FIG. 5
, a skeleton-like supporting structure
30
, on which a thin perforated tape
31
is applied centrically by means of welding or adhering. This perforated tape
31
is made for the purpose from a close-meshed woven or knitted fabric, preferably very thin polyamide filaments. The perforated tape
31
can thus be applied to the non-perforated areas
13
and
14
of a more stable supporting structure.
In order that the perforation
11
of the perforated tape
31
is completely effective, the supporting part of the transport belt
23
is provided with very wide longitudinal slits
33
, which are broken by cross-pieces
32
for the purpose of reinforcement.
In a variation of the present invention shown in
FIG. 6
, a transport belt
34
is provided, which takes the form of a very thin steel belt
35
. The thickness of the steel belt
35
can measure, for example, 0,4 mm. The steel belt
35
comprises a centrical perforation
36
, which is produced by etching. The edges of the transport belt
34
comprise again each a non-perforated area
13
,
14
.
In a particularly advantageous embodiment of the present invention as shown in
FIG. 7
, a transport belt
37
is provided, which has a non-perforated area
13
,
14
at the edges and an effective area
12
in a central area, the effective area
12
comprising a perforation
11
. The transport belt
37
is produced as a so-called skeleton belt
41
, which has primarily a supporting function and which furthermore serves the friction drive. This skeleton belt
41
is provided in the central area with a plurality of longitudinal slits
39
arranged one after the other in a row, and which are broken by cross-pieces
40
.
A thin, close-meshed woven fabric
38
of polyamide filaments is secured to the skeleton belt
41
in an exchangeable way. The exchangeability can be achieved in that the woven fabric
38
comprises coated edge zones
42
and
43
, with which the woven fabric
38
can be sealed or secured in some other way onto the skeleton belt
41
which is adapted to receive these coatings. The strength of the seal need only be such that the woven fabric
38
can be transported with the skeleton belt
41
during operation. The woven fabric
38
, when it is worn down, can be easily removed from the skeleton belt
41
to be replaced by a new one.
The perforation
11
of the woven fabric
38
is located to a great extent in the area of the longitudinal slits
39
, which are completely covered by the woven fabric
38
. It has been shown, that the cross-pieces
40
do not impair the quality of the yarn in any way.
Here also the width of the effective area
12
is chosen that the suction slit, located under the transport belt
37
, is completely covered. The very close-meshed, thin woven fabric
38
permits a particularly homogenous suction air stream, while the condensing effect is determined by the position and the arrangement of the suction slit
20
or
25
.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
Claims
- 1. A transport belt for transporting a fiber strand to be condensed over a suction slit of a condensing zone, said belt having a perforation for a suction air stream which suctions the fiber strand, wherein the transport belt comprises a non-perforated area which permits a friction drive, and an effective area containing the perforation, the width of which effective area is larger than the width of the suction slit.
- 2. A transport belt according to claim 1, wherein the transport belt is a flexible apron looped around a drive roller, said apron having holes arranged in a plurality of centrical row.
- 3. A transport belt according to claim 1, wherein the transport belt is a thin steel belt having a centrical perforation.
- 4. A transport belt according to claim 1, wherein the transport belt has a skeleton-like supporting structure, on which a thin perforated tape is applied centrically.
- 5. A transport belt according to claim 4, wherein the perforated tape is welded or adhered on.
- 6. A transport belt according to claim 5, wherein the perforated tape is made of a woven or knitted fabric.
- 7. A transport belt according to claim 4, wherein the perforated tape is applied in an exchangeable way.
- 8. A transport belt according to claim 6, wherein the perforated tape is made of a woven or knitted fabric.
- 9. A transport belt according to claim 4, wherein the perforated tape is made of a woven or knitted fabric.
- 10. A transport belt according to claim 4, wherein the supporting structure is a skeleton belt which is provided with wide longitudinal slits, broken by cross-pieces.
- 11. A transport belt according to claim 10, wherein the perforated tape is welded or adhered on.
- 12. A transport belt according to claim 10, wherein the is perforated tape is applied in an exchangeable way.
- 13. A transport belt according to claim 10, wherein the perforated tape is made of a woven or knitted fabric.
Priority Claims (1)
Number |
Date |
Country |
Kind |
198 37 179 |
Aug 1998 |
DE |
|
US Referenced Citations (6)