Textiles: fiber preparation – Working – Carding
Reexamination Certificate
2000-05-30
2001-05-15
Calvert, John J. (Department: 3765)
Textiles: fiber preparation
Working
Carding
C019S098000, C019S10600R, C019S109000
Reexamination Certificate
active
06230368
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention refers to machines for carding textile fibres in which staple fibres are processed so as to produce a web of fibres. During the operation, the fibres are cleaned, stretched out flat, and set parallel to one another in a thin web on the cloth of the carding drum, from which the fibre web is then removed by a rotating cylinder, normally called doffer, provided with a card cloth, and is then passed from a further cylinder, or stripper, to a compacting assembly and a drawing assembly to produce a ribbon of fibres.
In particular, the present invention regards the operation in which the web, which has been removed from the carding drum by the doffer, is then taken up by the stripper and delivered downstream to a controlled assembly for condensing the web into a ribbon and drawing it. This operation is the subject of the copending U.S. patent application No. 09/478,404, dated Jan. 6, 2000 in the name of the present applicant.
For a clearer illustration of the technical aspects and of the problems involved in the taking the web off the carding machine, reference is made to a diagram of the sequence which involves the carding drum, the doffer, the stripper and the compacter, which presented in
FIG. 1
in a schematic side view corresponding to the device described in the co-pending patent application, to which the reader is referred for further details as regards the operation and structure of the said device.
Downstream of the main carding drum
1
, the doffer of the carding machine is designated by
2
; on the latter the fibre web
3
is taken to the stripper
4
and conveyed to the compacting assembly made up of a pair of web-squeezing cylinders
5
,
6
, which are smooth, rotating and have a substantially horizontal axis; these compact the web
3
, the transverse dimension of which still corresponds to that of the carding drum, and pass it on to a subsequent belt conveyor
7
with a vertical working surface, which condenses the web into a ribbon. The compacting assembly works at a speed that is consistent with that of the web
3
coming from the stripper
4
. The two web-squeezing cylinders
5
and
6
are driven so that they turn with one and the same linear speed, thus preventing them from sliding and rubbing against one another. The drawn ribbon is then sent on to be collected in a vessel for further processing. Above the stripper
4
is set a device consisting of a rotating brush
8
for cleaning the stripper card cloth. The doffer is contained in the apron
9
made up of containment plates. Underneath the stripper
4
is set a transverse bar
11
for supporting the web
3
that has been stripped by the stripper
4
.
Underneath the stripper
4
, bar
11
and bottom web-squeezing cylinder
6
, is set a suction assembly
12
comprising a funnel-shaped connecting element
14
which is as wide as the generatrix of the doffer
2
and which connects the space
15
beneath the web
3
, which extends from the bar
11
to the web-squeezing cylinders
5
and
6
, to a suction duct
16
connected to the common aspiration system of the carding machine.
The space
15
is delimited by the scraper blades
17
, which are elastically pressed and constantly held so that they adhere and are tangential to the web-squeezing cylinders throughout their width.
A further cleaning treatment of the web
3
upon removal of the latter by means of the stripper
4
is carried out when the web
3
passes from the stripper to the two web-squeezing cylinders
5
,
6
, which are set immediately downstream of the stripper, by aspirating from the web
3
the impurities, which are also released owing to a the concurrent effect of the web being to a certain extent drawn during its passage through the cylinders, as is described and claimed in the copending patent application cited previously.
FIG. 2
shows a perspective view of a section of the assembly for removing the web from the doffer
2
, with the corresponding guards or containment plates all around.
The technical problem regards the web-squeezing rollers
5
,
6
and their blades
17
. The web-squeezing rollers
5
,
6
have the function of conveying and compressing the fibres—including their impurities, for example husks, which are still englobed in them—and may separate the web, causing local cuts, and generate irregularities in the final ribbon which is obtained from condensing of the web, or may even cause tearing of the web and arrest of the machine. The fibres and impurities that undesirably fail to follow the detachment the web
3
—which proceeds towards the condensing assembly
7
—, and that, instead, remain adherent to the web-squeezing rollers
5
and
6
, climb up towards the edge of their scraper blade and tend to work their way into the gap between the inner face of the blade
17
and the surface of the web-squeezing roller, thus adhering even more to the roller.
In order to maintain good operation of the surfaces of the web-squeezing rollers, in the known art the solution is adopted of making, on the said surfaces, spiral-shaped grooves
19
with one or more starts, which, in conjunction with the tangential blades
17
, hinder the undesired winding of the fibres. This technical solution makes it possible to reduce winding of the fibres on the rollers but presents the drawback that in the gap between the said blades and the surfaces of the rollers
5
,
6
there is an accumulation of material and that on the face of each blade coming into contact with a roller there is an accumulation of material against the edge of the blade and consequent dirtying of the inner face of the latter; this, in turn pushes the blades away from the rollers and is a further cause of the poor cleanliness of the rollers themselves and of a recirculation of fibres in the web. The aforesaid dirtying of the scraper blades
17
and of the web-squeezing rollers
5
,
6
calls for periodic manual maintenance operations with the machine not running which must be carried out by qualified staff. The quality of the ribbon produced depends, as a general rule, directly on the frequency of such operations. On the other hand, a high frequency of maintenance operations has an adverse effect on machine output, in so far as the operations require stoppage of the machine and decrease its output factor.
SUMMARY OF THE INVENTION
The device and the corresponding process for cleaning the elastic blades
17
and the web-squeezing rollers
5
,
6
according to the present invention perform the function of keeping both the said blades and the corresponding rollers clean, so eliminating, or at least considerably reducing, the need for manual intervention and for stoppages of the carding process, without jeopardizing the quality of the finished ribbon. The maintenance of cleanliness of the rollers and of the blades moreover makes possible a better air-tightness as regards the space
15
and a better cleaning of the web.
The invention is described in what follows with reference to a typical embodiment, which is illustrated in
FIGS. 3
to
5
, merely to provide a non-limiting example and to highlight further the characteristics and advantages of the present invention, with reference to the annexed schematic drawings, in which:
REFERENCES:
patent: 2464425 (1949-03-01), White
patent: 2823423 (1958-02-01), Suzuki
patent: 3145428 (1964-08-01), Reiterer
patent: 3235911 (1966-02-01), Reiterer
patent: 4274178 (1981-06-01), Hotta
patent: 4332058 (1982-06-01), Warnock
patent: 901 035 (1954-01-01), None
patent: 852 207 (1940-01-01), None
patent: 1 586 479 (1981-03-01), None
Patent Abstracts of Japan, vol. 013, No. 024 (C-561), Jan. 19, 1989, JP 63 227816, Sep. 22, 1988.
U.S. application No. 09/478,404, filed Jan. 6, 2000, pending.
U.S. application No. 09/579,132, May 30, 2000, pending.
Galli Massimo
Pasini Giovanni Battista
Patelli Silvano
Calvert John J.
Marzoli S.p.A.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Welch Gary L.
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