U.S. patent application number 10/471185 was filed with the patent office on 2004-09-02 for method and device for the production of tubular knitted articles and in particular for closing the toe.
Invention is credited to Conti, Paolo.
Application Number | 20040168478 10/471185 |
Document ID | / |
Family ID | 11442095 |
Filed Date | 2004-09-02 |
United States Patent
Application |
20040168478 |
Kind Code |
A1 |
Conti, Paolo |
September 2, 2004 |
Method and device for the production of tubular knitted articles
and in particular for closing the toe
Abstract
Described herein is a method for forming a closed toe in a
tubular knitted article, for example a sock, comprising the steps
of: setting two end flaps (L1, L2) of the article (M) alongside one
another; inserting, inside the loops of at least one first row (X2)
of stitches of the flaps set alongside one another, a comb-like
structure comprising a plurality of teeth (85); sewing (C) together
the loops of at least one second row of stitches, which is set
between the first row of stitches (X2) and the body of the tubular
article (M); and opening the loops of the first row of
stitches.
Inventors: |
Conti, Paolo; (Firenze,
IT) |
Correspondence
Address: |
MCGLEW & TUTTLE, PC
1 SCARBOROUGH STATION PLAZA
SCARBOROUGH
NY
10510-0827
US
|
Family ID: |
11442095 |
Appl. No.: |
10/471185 |
Filed: |
March 31, 2004 |
PCT Filed: |
March 4, 2002 |
PCT NO: |
PCT/IT02/00130 |
Current U.S.
Class: |
66/147 |
Current CPC
Class: |
D04B 15/92 20130101;
D05B 7/00 20130101; D05B 23/007 20130101; D05B 23/009 20130101;
D04B 9/40 20130101 |
Class at
Publication: |
066/147 |
International
Class: |
D04B 035/00 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 8, 2001 |
IT |
FI01A000037 |
Claims
1. A method for forming a closed toe in a tubular knitted article,
comprising the steps of: setting two end flaps of said article
alongside one another; inserting, inside the loops of at least one
first row of stitches of said end flaps, a comb-like structure
comprising a plurality of teeth; sewing together the loops of at
least one second row of stitches, which is set between said first
row of stitches and the body of the tubular article; and opening
the loops of the first row of stitches.
2. The method according to claim 1, in which the loops of said
second row are sewn together by joining each loop of one first of
said two flaps to a corresponding loop of one second of said two
flaps by means of a stitch formed by a sewing thread.
3. The method according to claim 2, in which said sewing thread
forms at least one chain of loops, in which between the stitches
that join the two flaps there are interspersed stitches that do not
join the flaps of the tubular article.
4. The method according to one or more of the foregoing claims, in
which said loops of the first row are opened by cutting.
5. The method according to claim 4, further comprising a step of
elimination of the residue of yarn generated by cutting of said
loops of the first row.
6. The method according to one or more of claims 1 to 3, in which
said loops of the first row are obtained using a destructible
yarn.
7. The method according to claim 6, in which said destructible yarn
is a yarn that can be destroyed by heating.
8. The method according to one or more of the foregoing claims, in
which the loops of said first row have a greater length than the
loops of said second row and than the remaining loops forming the
tubular article.
9. The method according to claim 8, in which the loops of said
second row have a length smaller than the loops of the first row
but greater than the length of the loops of the remaining rows of
the tubular article.
10. The method according to one or more of the foregoing claims, in
which the loops of said at least one second row are sewn with a
seam having a pitch smaller than the pitch of said loops.
11. The method according to claim 10, in which the loops of said at
least one second row are sewn with a sewing pitch equal to or
smaller than one half of the pitch of said loops.
12. The method according to one or more of the foregoing claims, in
which the loops of said at least one second row are sewn with a
sewing pitch smaller than the pitch of the teeth of said comb-like
structure.
13. The method according to claim 12, in which the loops of said at
least one second row are sewn with a sewing pitch equal to or
smaller than one half of the pitch of the teeth of said comb-like
structure.
14. The method according to one or more of the foregoing claims,
comprising the steps of: gripping two roughly diametrically
opposite points of the tubular article, in positions corresponding
to said end flaps; tensioning transversely said tubular article in
order to bring said end flaps alongside one another; tensioning
said tubular article longitudinally; inserting said comb-like
structure into said first row of loops in such a way that each
tooth of said comb-like structure inserts into a loop of one first
flap and into a corresponding loop of the second flap; sewing
together the loops of said at least one second row; and opening the
loops of said first row.
15. The method according to one or more of the foregoing claims, in
which sewing of the loops of the second row is performed by means
of a seam of the single-chain type.
16. A method for the production of a tubular article with a closed
end toe, comprising the steps of: knitting the tubular article
starting from an initial edge as far as an end edge; setting the
two end flaps of said end edge alongside one another; inserting,
inside the loops of at least one first row of stitches of said end
flaps, a comb-like structure comprising a plurality of teeth;
sewing together the loops of at least one second row of stitches,
which is set between said first row of stitches and the body of the
tubular article; and opening the loops of the first row of
stitches.
17. The method according to claim 16, in which the loops of said
second row are sewn together by joining the loops of one first of
said two flaps to a corresponding loop of one second of said two
flaps by means of a stitch formed by a sewing thread.
18. The method according to claim 17, in which said sewing thread
forms at least one chain of stitches, in which between the stitches
that join the two flaps there are interspersed stitches that do not
join the two flaps of the tubular article.
19. The method according to one or more of claims 16 to 18, in
which said loops of the first row are opened by cutting.
20. The method according to claim 19, further comprising a step of
elimination of the residue of yarn generated by cutting of said
loops of the first row.
21. The method according to one or more of claims 16 to 18, in
which said loops of the first row are obtained using a destructible
yarn.
22. The method according to claim 21, in which said destructible
yarn is a yarn that can be destroyed by heating.
23. The method according to one or more of claims 16 to 22, in
which the body of the article is knitted and, at the end of
knitting of the body of the article, at least said first row of
stitches is formed with loops having a greater length than the
loops of the rows that form the body of the article.
24. The method according to claim 23, in which after said first row
of stitches, a band of fabric is formed having a greater thickness
than the fabric forming the body of the article.
25. The method according to one or more of claims 16 to 24, in
which the loops of said at least one second row are sewn with a
seam having a pitch smaller than the pitch of said loops.
26. The method according to claim 25, in which the loops of said at
least one second row are sewn with a sewing pitch equal to or
smaller than one half of the pitch of said loops.
27. The method according to one or more of claims 16 to 26, in
which the loops of said at least one second row are sewn with a
sewing pitch smaller than the pitch of the teeth of said comb-like
structure.
28. The method according to claim 27, in which the loops of said at
least one second row are sewn with a sewing pitch equal to or
smaller than one half of the pitch of the teeth of said comb-like
structure.
29. The method according to one or more of claims 16 to 28,
comprising the steps of: gripping two roughly diametrically
opposite points of the tubular article, in positions corresponding
to said end flaps; tensioning transversely said tubular article in
order to bring said end flaps alongside one another; tensioning
said tubular article longitudinally; inserting said comb-like
structure into said first row of loops in such a way that each
tooth of said comb-like structure inserts into a loop of one first
flap and into a corresponding loop of the second flap; sewing
together the loops of said at least one second row; and opening the
loops of said first row.
30. The method according to one or more of claims 16 to 29, in
which sewing of the loops of the second row is performed by means
of a seam of the single-chain type.
31. A device for sewing two end flaps of a tubular knitted article
and for forming a closed toe of said article, said device
comprising in combination: a comb-like structure with a plurality
of teeth for engaging the loops of a first row of said tubular
article; and sewing means with at least one needle, for sewing
together the flaps set alongside one another underneath the
comb-like structure.
32. The device according to claim 31, comprising a gripping member
for gripping said tubular article at one end edge thereof in two
approximately diametrically opposite points, in order to tension
the end edge and to bring two end flaps of said tubular article
alongside one another.
33. The device according to claim 31 or claim 32, comprising a
cutting member for cutting the loops engaged by said comb-like
structure.
34. The device according to claim 33, comprising a member for
removal of the residue of yarn generated by cutting of the
loops.
35. The device according to one or more of claims 31 to 34, further
comprising a pair of substantially rectilinear bars associated to
said comb-like structure and parallel to the latter, between which
the tubular article is pressed with the end flaps set alongside one
another.
36. The device according to claim 35, in which said comb-like
structure is carried by one of said bars and is mobile with respect
to the latter.
37. The device according to one or more of claims 31 to 36, in
which within the teeth of said comb-like structure there is formed
a seat for said cutting member.
38. The device according to one or more of claims 31 to 37, in
which said cutting member is provided with a cutting movement with
a component parallel and a component orthogonal to the longitudinal
development of the comb-like structure.
39. The device according to one or more of claims 31 to 38,
comprising a retention member for retaining the tubular article
between the comb-like structure and the body of the tubular article
during cutting of the stitches engaged by the comb-like
structure.
40. The device according to claim 31, comprising a guillotine in
which the end edge of the article is to be inserted, said
guillotine and said comb-like structure having a relative movement
for enabling insertion of the comb-like structure into the tubular
article engaged in said guillotine.
41. The device according to one or more of claims 31 to 40, in
which said comb-like structure is a flexible structure.
42. A knitting machine for the production of tubular knitting
articles, comprising a device according to one or more of claims 31
to 41.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for producing
tubular knitted articles, such as socks and stockings, and in
particular for closing the toe of the article by joining the two
flaps of the toe.
STATE OF THE ART
[0002] In the production of tubular knitted articles, in particular
stockings and socks for men, for sportswear and the like, the
product is knitted on a knitting machine, in particular but not
exclusively of a circular type, which is a machine equipped with a
needle cylinder. The article thus produced has an initial edge and
an end edge. The end edge must be closed to form the toe of the
article. For this purpose, up to now a linking process has been
used, which is carried out on so-called linking machines. Said
process involves a high incidence in terms of labour. According to
this process, the flaps of the end edge of the article are
tensioned and set alongside one another, and are then hooked onto
hooks of a linking machine. In carrying out this operation, it is
essential to hook each stitch or loop of a given row of stitches
onto a respective hook. In greater detail, on each hook there are
hooked two corresponding stitches or loops, of the same row,
belonging to the two flaps set alongside one another of the end
edge of the article. Once the article has been applied on the
hooks, linking proper is carried out automatically, with the
formation of a particular seam by means of a thread of yarn that
forms a row of sewing loops or stitches that intersect the stitches
or loops that are set on the hooks. To each pair of loops present
on a hook there corresponds a stitch of the seam that joins the
flaps. Next, the stitches or loops that are set externally to the
seam are cut, namely the stitches of the row of stitches adjacent
to the hooks on the side opposite to the one where the tubular
article is set. Finally, the latter is removed from the hooks.
[0003] Linking enables a practically faultless and particularly
smooth closed toe to be obtained. However, as is known to persons
skilled in the art and as may be understood from the foregoing
brief description, the process involves a marked incidence in terms
of labour for hooking the individual loops or stitches of the row
that is to be sewn on the hooks of the linking machine. The
operation must be carried out by staff with particularly sharp
eyesight, and consequently can, in general, be performed only by
young people.
[0004] The cost and difficulty in finding staff suitable for
carrying out these operations renders recourse to the linking
operation increasingly less frequent. As an alternative to linking,
the toes of tubular articles are closed by means of seams obtained
in a completely mechanized way, or in any case with a low incidence
in terms of labour. The quality of the finished product is,
however, inferior, in so far as mechanized seams involve the
execution of a plurality of stitches distributed in an altogether
random way, which generate a seam with a large thickness. A device
and a process for closing the toe using a sewing machine associated
to a knitting machine are described in WO-A-00/01869.
[0005] EP-A-0 635 593 and EP-A-0 592 376 describe a method and a
device for joining two flaps of a knitted fabric of a tubular
article for forming the closed toe of the finished article. In this
case, closing is carried out directly on the circular knitting
machine. The seam is obtained automatically, but requires a
substantial modification of the knitting machine.
OBJECTS AND SUMMARY OF THE INVENTION
[0006] A purpose of the present invention is to provide a method
and a process for closing the toe of a tubular knitted article,
which can be easily automated and which ensures a high-quality
product.
[0007] According to another aspect, a further object of the present
invention is to provide a method for the production of a tubular
knitted article which enables manufacture of a tubular knitted
article with a toe closed with a high-quality seam, without the
drawbacks of the known linking processes.
[0008] According to a different aspect, yet a further object of the
present invention is to provide a device which will enable closing
of the toe of a tubular knitted article with a high-quality seam,
without a high incidence in terms of labour, and which will enable
high levels of output to be achieved.
[0009] In order to obtain closing of the tubular knitted article,
the method according to the invention envisages setting two flaps
of the end edge of the article alongside one another, in particular
by gripping, for example, two roughly diametrically opposite points
of the edge itself and tensioning the fabric. Into the stitches or
loops of at least one row of the end edge there are then inserted
the teeth of a comb-like structure, and the loops are thus aligned
for subsequent sewing. Then a seam is made for joining the flaps of
woven fabric, at the stitches or loops of a row adjacent to the one
in which the teeth of the comb-like structure are inserted; more in
particular, the row of stitches on which sewing is performed is the
one located between the, comb-like structure and the body of the
tubular article. Next, once sewing of the loops of this second row
has been performed, the loops into which the comb-like structure
has been inserted are opened. According to a preferred embodiment
of the invention, opening of the loops into which the comb-like
structure is inserted is done by cutting the yarn. However, the
possibility is not ruled out of performing this opening in a
different way. For example, it is possible to form the row of
stitches that is to receive the teeth of the comb-like structure
using a thread of yarn that melts at a relatively high temperature,
for example at the temperature of the dyeing liquid. In this way,
once joining of the flaps of the tubular article for closing the
toe has been performed, the article is discharged and sent on to
subsequent processing stages. One of these involves dipping of the
article into a bath at a relatively high temperature, for example,
a dye bath, in which the meltable thread is destroyed, with
consequent opening of the stitches formed thereby. This results in
detachment of the rows outside the seam that joins the flaps. In
what follows, reference will be normally made to an operation of
cutting of the stitches, but it must be understood that this
operation may be replaced by a different operation that leads to
the same result, namely, opening of the stitches or interruption of
the fabric with consequent separation of the tubular article from
the end edge outside the seam.
[0010] When opening of the stitches is performed by cutting, it is
advantageous to envisage an operation of extraction of the residue
of the stitches that have been cut, for example using a brush or
some other removing member. This operation is not necessary when a
meltable thread is used, in so far as the latter is completely
eliminated by heating.
[0011] As compared to a normal linking process, both sewing and the
subsequent cutting or opening of the loops are carried out on rows
of stitches other than those that are sewn and cut according to the
prior art.
[0012] As will emerge clearly from the ensuing descriptions the
method described above can be conveniently carried out in an
automatic and entirely mechanized way. This is particularly
facilitated if the stitches of the row into which the teeth of the
comb-like structure are inserted have a greater length than the
remaining stitches of the article. In this way, insertion of the
comb-like structure into the loops or stitches of the aforesaid row
is extremely facilitated and can be carried out by a mechanical
hand without any difficulty. Preferably, also the stitches on which
sewing is carried out are longer than the remaining stitches of the
tubular article, even though they are preferably shorter than the
stitches of the row into which the teeth of the comb-like structure
are inserted.
[0013] The method can advantageously be entirely automated, but
this does not rule out the possibility of carrying it out also in a
manual or semi-manual way, as will be described hereinafter by way
of example on the basis of a series of examples of embodiment.
[0014] In practice, with the method of the present invention it is
possible to obtain a seam for joining the flaps of the tubular
article that is equivalent to a linking seam proper, in so far as
the sewing thread produces a chain of stitches or loops which
intersect individual pairs of stitches of the two flaps set
alongside one another of the tubular article, in a way similar to
what happens in linking machines, but with much simpler and
automatable procedures.
[0015] In order to guarantee that all the stitches or loops of the
row adjacent to the one where the teeth of the comb-like structure
are inserted will be engaged with corresponding stitches of the
seam for closing the toe, even in the case where insertion of the
teeth into the loops were not perfectly regular (for example, if a
tooth engages two adjacent loops of the same flap), it may
advantageously be envisaged that the pitch of the seam joining the
flaps of the article will be smaller than the, pitch of the
comb-like structure or of the stitches or loops. For example, the
pitch of the knitted seam may be a submultiple, for instance one
half or one third, of the pitch of the loops of the row of fabric
that is to be sewn, or of the pitch of the comb-like structure.
[0016] In practice, the method according to the invention envisages
the following steps:
[0017] gripping two roughly diametrically opposite points of the
tubular article, in positions corresponding to said end flaps;
[0018] tensioning transversely said tubular article in order to
bring said end flaps alongside one another;
[0019] tensioning said tubular article longitudinally;
[0020] inserting said comb-like structure into said first row of
loops in such a way that each tooth of said comb-like structure
inserts into a loop of one first flap and into a corresponding loop
of the second flap;
[0021] sewing together the loops of said at least one second row
adjacent to the first row; and
[0022] cutting the loops of said first row and sliding out the
half-loops that have been cut, or else opening the loops in some
other way.
[0023] As is known, normally the structure of a knitted fabric is
helical, in the sense that if the yarn is fed continuously, a
continuous helical sequence of stitches is generated. If the
tubular article has a structure of this type, the teeth of the
comb-like structure may end up inserting into adjacent rows, and
likewise the loops formed by sewing may end up joining
corresponding stitches of the two flaps set alongside one another
which belong to different rows. This does not affect in a
substantial way the final result, thanks to the deformability of
the structure of the fabric.
[0024] However, according to a preferred embodiment of the
invention, the row into which the teeth of the comb-like structure
insert and the row on which sewing is performed, as well as
possibly some of the rows immediately before and immediately after,
may be obtained by interrupting the thread of yarn, in such a way
that at these rows there will be entry and exit of the thread of
yarn that forms the stitches. This results in circular rows instead
of helical ones and facilitates insertion of the comb-like
structure, as well as the sewing or linking operation, which will
be performed at the level of a single row without any overlapping.
The detailed description of an example of embodiment will clarify
further this particular feature.
[0025] The method according to the invention for closing the toe of
a tubular knitted article may be carried out at a moment and/or in
an area different from the moment and/or area of knitting of the
tubular article, as currently occurs for the linking process, which
is carried out separately from and independently of the process of
knitting of tubular articles.
[0026] Alternatively, and advantageously, the method for closing
the toe may be implemented directly on the machine, or in a
position adjacent to the machine, on which said article is
manufactured. In this case, the sewing method is integrated in a
method for knitting the tubular article. The method will thus
involve the following steps:
[0027] knitting the tubular article starting from an initial edge
as far as an end edge;
[0028] setting the two end flaps of said end edge alongside one
another;
[0029] inserting, inside the loops of at least one first row of
stitches of said end flaps, a comb-like structure comprising a
plurality of teeth;
[0030] sewing together the loops of at least one second row of
stitches, which is set between said first row of stitches and the
body of the tubular article; and
[0031] opening (for example by cutting) the loops of the first row
of stitches into which the teeth of said comb-like structure have
been inserted.
[0032] In any case, the process for knitting the article may
envisage, according to a preferred embodiment of the invention, the
formation of a row of stitches or loops of a larger size or length
in order to facilitate insertion of the teeth of the comb-like
structure.
[0033] According to a further aspect of the invention, a device is
provided for sewing two end flaps of a tubular knitted article,
said device comprising in combination:
[0034] a comb-like structure with a plurality of teeth for engaging
the loops of a first row of said tubular article; and
[0035] possibly a gripping member for gripping said tubular article
at an end edge of the article in two approximately diametrically
opposite points, in order to tension the end edge and to bring two
end flaps of said tubular article alongside one another; and
[0036] sewing means with at least one needle for sewing together
the flaps set alongside one another underneath the comb-like
structure.
[0037] The gripping member for gripping and tensioning the article
may even be omitted, in which case said operation may be carried
out manually, for example by inserting the edge of the article with
the flaps brought up to one another into a so-called guillotine
made up of two bars set alongside one another.
[0038] Advantageously, also a cutting member may be provided for
cutting the loops engaged by said comb-like structure, as well as,
preferably, means for removal of the half-loops cut by the cutting
member. However, as mentioned previously, opening of the loops
adjacent to the seam may be carried out also in a way other than by
cutting. In this case, the cutting member and the means for removal
of the residual yarn of the half-loops that have been cut may not
be present.
[0039] In a particular advantageous embodiment of the invention,
the device is also provided with a pair of substantially
rectilinear bars associated to the comb-like structure and parallel
to the latter, between which the tubular article is pressed and
engages with the end flaps set alongside one another for insertion
of the comb-like structure. The latter may be independent of the
pair of bars, or else may be advantageously carried by one of the
bars and be mobile with respect to the latter.
[0040] In order to facilitate the operations of cutting of the
loops of the row inside which the comb-like structure has been
inserted, according to a particularly advantageous embodiment of
the invention the cutting device is incorporated in the comb-like
structure. Said cutting device may comprise a blade housed in a
slidable way within a seat made in the teeth of the comb-like
structure. For an efficient cut, movement of the blade may have a
component that is parallel and a component that is orthogonal to
the development of the teeth of the comb-like structure. The
possibility is not ruled out of making and setting the cutting
member in a different way, instead of incorporating it in the
comb-like structure, although the latter solution presents
advantages from the constructional standpoint.
[0041] Further advantageous characteristics of the device and
method according to the invention are specified in the attached
claims.
[0042] Described in what follows is an apparatus comprising the
device according to the invention, which has also the function of
extracting the tubular article from the circular knitting machine
and taking it to the area where the sewing device proper for sewing
the toe is provided. It must be understood that the ensuing
description only refers to one of the possible uses of the device
and the method according to the present invention, which may be
implemented also in different machines and equipment. For example,
it is possible to envisage use of the device and method according
to the invention also in combination with an apparatus of the type
described in WO-A-00/01869, instead of in combination with the
sewing machine described herein, or else in combination with one of
the devices described in EP-A-0 679 746, or in combination with
other suitable apparatus. The device and method according to the
present invention can also be used, for instance, in combination
with a machine of the type described in the co-pending European
patent application No. 00830020.4 of Jan. 18, 2000 or in the
corresponding international patent application PCT/IT01/00009 of
Jan. 12, 2001.
[0043] In general, the invention may be adopted also in isolation,
instead of in combination with a knitting machine with the
corresponding means for extracting and handling the tubular
article. It is in fact possible to envisage picking-up of the
tubular articles from a container where they have been set
pell-mell after they have been manufactured in an independent
production department. In this case, the step of preparation of the
tubular article for the subsequent sewing step may be entirely
mechanized or mechanized only in part by envisaging, for instance,
intervention of an operator who sets the tubular articles that are
to be sewn on an appropriate support, for example consisting of the
end part of a tubular duct. The remaining operations of tensioning,
positioning, sewing and discharging may be mechanized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] A better understanding of the present invention will be
provided by the ensuing description and by the attached drawings,
which illustrate a non-limiting example of embodiment of the
invention. In greater detail, in the drawings:
[0045] FIG. 1 is a perspective view of a device for picking up a
tubular knitted article from a cylinder of a circular knitting
machine and of a device for sewing the toe of the article;
[0046] FIG. 2 is a side view according to the line II-II of FIG.
1;
[0047] FIG. 3 is a view according to the line III-III of FIG.
2;
[0048] FIG. 4 is a perspective view of the devices combined with a
circular knitting machine;
[0049] FIG. 5 is a perspective view of one part of the sewing area,
with elements removed for reasons of greater clarity of the
drawing;
[0050] FIG. 6 is similar to FIG. 5 and shows the same members from
a different observation point;
[0051] FIG. 7 is a perspective view of the sewing machine for
closing the toes of tubular articles picked up by the pick-up
device;
[0052] FIG. 8 is a perspective view of an intermediate separator
set along a suction pipe of the pick-up device;
[0053] FIG. 9 shows the internal members of the intermediate
separator of FIG. 8;
[0054] FIG. 10 is a longitudinal cross-sectional view of the
intermediate separator;
[0055] FIG. 11 shows a mobile axial unit that carries the widening
members and the members for turning the tubular article inside out
for preparing it for sewing of the toe;
[0056] FIG. 12 shows the same unit as FIG. 11 with parts
removed;
[0057] FIG. 13 is a longitudinal cross-sectional view of the unit
of FIGS. 11 and 12;
[0058] FIG. 14 is a view from below according to the line XIV-XIV
of FIG. 13;
[0059] FIG. 15 shows a pair of bars for retention of the article
during the initial steps of sewing of the toe;
[0060] FIG. 16 shows a comb-like structure for engagement of the
article during sewing and a cutting member housed inside the
comb-like structure;
[0061] FIGS. 17 to 28 show, in a cross-sectional plane passing
through the axis of the suction pipe, the device for picking up the
article (or part of the device), as well as the widening members
and the members for turning the article inside out in order to
prepare it for sewing of the toe, FIG. 17A being an enlargement of
the output area of the suction pipe;
[0062] FIG. 29 is a cross-sectional view according to the line
XXIX-XXIX of FIG. 28;
[0063] FIG. 29A is an enlargement of the central area of FIG.
29;
[0064] FIGS. 30 to 32 are cross-sectional views, according to the
line XXX-XXX of FIG. 29, of the pair of bars for retention of the
article and of the comb-like structure in the step of engagement of
the article and insertion of the comb-like structure into the
respective row of stitches, as a preliminary step to sewing of the
toe;
[0065] FIG. 33 shows the sewing machine and the comb-like structure
inserted in the article during sewing;
[0066] FIG. 34 is an enlargement of a detail of FIG. 33;
[0067] FIG. 35 is a schematic illustration of the action of the
needle of the sewing machine during the sewing operation;
[0068] FIGS. 36 to 39 show the steps for cutting the loops of the
row of the tubular article inside which the comb-like structure has
been inserted;
[0069] FIG. 40 shows the step of removal of the residue of yarn
after cutting of the loops adjacent to the sewing row;
[0070] FIG. 41 illustrates a detail of FIG. 40;
[0071] FIG. 42 is a perspective view illustrating a possible
embodiment of the system for removal of the residue of yarn;
[0072] FIG. 43 is an axial sectional view of the end portion of the
suction pipe in the step of removal of the tubular article after
the sewing operation;
[0073] FIGS. 44 to 46 are schematic representations of the weaving
operations performed on the article during sewing of the toe;
[0074] FIG. 47 is a schematic representation of the rows involved
in sewing in an improved embodiment of the invention;
[0075] FIGS. 48 and 49 are perspective views of a semi-automatic
sewing device according to the invention, in two different
operating positions;
[0076] FIG. 49A illustrates an enlarged detail of FIG. 49;
[0077] FIG. 50 is a perspective view of the sewing machine combined
with the device of FIGS. 48 and 49, with parts removed;
[0078] FIGS. 51 to 53 show details of the sewing and cutting area
of the device of FIGS. 48 and 49; and
[0079] FIG. 54 is a perspective view illustrating another
semi-automatic device according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE
INVENTION
[0080] The devices for picking up and sewing tubular articles are
shown in FIG. 4 in combination with a circular knitting machine,
and in isolation from the knitting machine in FIGS. 1 to 3. The
internal structure of the pick-up device may be seen in FIGS. 17 to
28. In some of the figures, parts of the devices have been removed
for greater clarity of representation. In what follows generic
reference will frequently be made to the ensemble made up of the
pick-up device and sewing device as to a single device for picking
up the article and closing the toe, it being, however, understood
that the pick-up device may be combined with a different device for
closing the toe and vice versa.
[0081] In the attached drawings, the device for picking up the
tubular article and closing the toe is designated, as a whole, by
1, whilst 3 designates, as a whole, the circular knitting machine
that produces the tubular article. Of the circular knitting machine
3, only the essential components are indicated, which may be seen
in particular in FIGS. 17 to 19, which show the cylinder 5 of the
needles 7 that form a circular needle bed, in a way in itself
known. The needle cylinder 5 is supported, in such a way that it
can turn about its own axis, by means of a support, designated by
9, and is set in rotation by means of members (not illustrated)
which mesh with a crown gear 11. The members for controlling the
needles 7 of the circular bed are not shown, but are in themselves
known, as are also all the other members of the circular knitting
machine 3, which consequently will not be described in any further
detail herein.
[0082] The device 1 comprises a suction pipe 13, which is
substantially U-shaped, and one end of which, designated by 13A,
will hereinafter be referred to as intake end, whilst one end,
designated by 13B, will hereinafter be referred to as output end.
The intake end 13A is set underneath the cylinder 5 of the needles
7 of the knitting machine 3. In this way, the suction pipe 13 may
have any diameter whatsoever, which is independent of the internal
diameter of the cylinder 5.
[0083] Inside the suction pipe 13 there develops a guide element,
designated as a whole by 15. Said guide element 15 (which in the
example illustrated has a substantially tubular conformation with a
circular cross section) extends outside the suction pipe 13 from
the intake end 13A as far as inside the cylinder 5 of the needles 7
of the knitting machine 3. The top end of the guide element 15
approximately reaches the plane of formation of the knitted fabric
of the knitting machine 3.
[0084] The guide element 15 is made up of two parts, one of which
is designated by 15A and the other by 15B. These two parts are
hinged about an axis of trace 17 (see in particular FIG. 17)
orthogonal to the axis (namely, to the median line) of the suction
pipe 13 and of the guide element 15 itself. The reason for this
configuration will appear more clearly from the ensuing description
of the operation of discharge of the article with the toe
closed.
[0085] The guide element 15 is supported, inside the suction pipe
13, by means of an intermediate separator, which is designated as a
whole by 19, and the parts of which are illustrated in detail in
FIGS. 8 to 10. The intermediate separator 19 also performs the
function of dividing the suction pipe 13 into two consecutive
parts, the first of which develops between the intake end 13A and
the intermediate separator 19, and the second between the latter
and the output end 13B.
[0086] As may be seen in detail in FIGS. 8 to 10, the intermediate
separator 19 is made up of a pair of jaws 21 and 22 operated by
respective actuators 23 and 24, which, in the example illustrated,
consist of cylinder-piston systems. The jaws 21 and 22 are fixed to
the stems of the cylinder-piston actuators 23 and 24 and have
V-shaped front profiles, designated by 21V and 22V. The jaw 21 has
a slot, inside which the front portion of the jaw 22 penetrates in
such a way as to grip, between the two profiles 21V and 22V, the
guide element 15, withholding it in a coaxial position, namely
centred with respect to the suction pipe 13.
[0087] The jaws 21 and 22 slide in a guide frame 25 which is fixed
to the suction pipe 13.
[0088] As may be seen in FIGS. 9 and 10 (in the latter figure the
jaws 21 and 22 being shown in the closed condition), the jaw 22 has
an internal duct, designated by 27, which opens onto the profile
22V and onto the top portion of the jaw itself (see in particular
FIG. 9). The frame 25 has a slotted opening 29 in a position
corresponding to the outlet area of the internal duct 27 to enable
application of a flexible pipe or hose that connects the internal
duct 27 to a source of air under pressure (not shown) for the
purposes that will be clarified in what follows.
[0089] As may be seen in particular in FIGS. 17, 18 and 19, the
guide element 15 has (in its part 15B) a hollow structure inside
which a stem 15C is housed that terminates with a head 15E (see in
particular FIG. 17A), said stem constituting a telescopically
extensible portion of the guide element itself. The reference
number 15D designates a extension spring that forces the stem 15C
to return into the hollow tubular part of the guide element. The
air under pressure, which can be supplied through the internal duct
27 of the jaw 22, has the function of pressurizing the internal
area of the hollow part 15B of the guide element 15 to overcome the
force of the extension spring 15D and to extract the stem 15C until
it reaches the position illustrated in FIGS. 17 to 19, whilst in
FIG. 20 the stem 15C is shown in a retracted position inside the
hollow part of the guide element 15.
[0090] Since the jaws 21 and 22 of the intermediate separator 19
can open, thus releasing the guide element 15 in order to enable
passage of the tubular article which must pass along the suction
pipe 13 (as will be clarified in what follows), along the suction
pipe 13 there are provided further systems for temporary support of
the guide element 15 inside the suction pipe 13. These supporting
means are clearly visible in FIGS. 1, 2 and 3 and are represented
in a simplified way in the remaining figures. They are made up of
three sets of sliders 31, 32, 33 positioned in respective three
sections set at distances apart along the development of the
suction pipe 13. In greater detail, two sets of three sliders,
namely the sets of three sliders 31 and 32, are positioned on
planes orthogonal to the axis of the suction pipe between the
intake end 13A of the suction pipe and the intermediate separator
19. The last set of sliders 33 is positioned on a plane between the
intermediate separator 19 and the output end 13B of the suction
pipe 13. The sets of sliders 31, 32 and 33 can be brought back or
retracted in such a way that they do not project inside the suction
pipe 13, so as to leave completely free the space between the inner
wall of the suction pipe 13 and the guide element 15.
Alternatively, the sliders of each set can be displaced radially
inwards in such a way that they engage the guide element 15,
supporting it inside the suction pipe 13. Synchronized actuation of
the sets of sliders 31, 32, 33 enables (in the way that will be
clarified hereinafter) transit of the tubular article discharged
from the circular needle bed 37 along the suction pipe 13 towards
the output end 13B of the latter.
[0091] The suction pipe 13 has an end part 13C which is angularly
mobile about its own axis with respect to the remaining part of the
suction pipe. The movement of rotation of the end part 13C of the
suction pipe 13 is imparted by an actuator 35, for example a
stepper motor. The latter enables adjustment of the angular
position of the part 13C of the suction pipe 13 with respect to the
remaining part (which is fixed on the supporting structure) of the
pipe, in order to orient appropriately the tubular article before
sewing of the toe of the latter, as will emerge clearly from the
detailed description of the modes of operation of the entire
device.
[0092] At the output end 13B of the suction pipe 13 there is
provided a sewing area, designated as a whole by 37. Located in
this area are the members that have the function of extracting the
tubular article, turning it inside out, from inside the suction
pipe 13, of closing the toe of said article by sewing and
re-inserting the article into the suction pipe 13 so as to
discharge it finally from the device.
[0093] Set in the sewing area 37 is a unit 39 which surrounds the
suction pipe 13, and more precisely the portion 13C of the latter.
The unit 39 carries, in a way that will be described in detail with
reference to FIGS. 11 to 14, the widening members and the members
for turning the tubular article inside out before it is sewn. The
unit 39 is axially mobile, in the direction indicated by the arrow
f39, along the end part 13C of the suction pipe 13. For this
purpose, there are provided a slide guide 41 and an actuator 43
which controls movement of the unit 39.
[0094] The unit 39 is illustrated in detail in a perspective view
in FIGS. 11 and 12, in a cross-sectional view in FIG. 13, and in a
view from below in FIG. 14. FIG. 11 shows a ring 45 which forms
part of the unit 39 and which is coaxial with the axis of the part
13C of the suction pipe 13. The ring 45 supports a plurality of
radial pushers 47 constituting the members for turning the tubular
article inside out before sewing of the toe. Each pusher 47 is
provided with a radial movement controlled by a corresponding
actuator 49, for example a small cylinder-piston actuator. Beneath
the ring 45, the unit 39 has a wall 51 which delimits an internal
suction chamber 53. The latter is connected, through an opening 55,
to a suction line, the connection of which to the suction chamber
53 is designated by 57.
[0095] Set inside the suction chamber 53 present in the unit 39 are
five-shaped plates 59 supported by rotating spindles 61. Each
shaped plate 59 carries, in a position at a distance from the
corresponding supporting spindle 61, a stem 63 parallel to the
spindle 61 itself. The conformation of the shaped plates 59 is such
that (see in particular FIG. 12, in which the overlying pushers 47,
their actuators 49 and the ring 45 have been removed for clarity of
representation), in a first angular position of the spindles 61,
they form a substantially continuous wall orthogonal to the axis of
the suction pipe 13, or more exactly to the end part 13C of the
suction pipe 13. The wall formed by the shaped plates 59 has a
central hole 65 for the purposes that will be clarified
hereinafter.
[0096] The shaped plates 59 are controlled in such a way that they
open simultaneously by means of an oscillation of each spindle 61
about its own axis. For this purpose, a mechanism is provided,
which is shown in FIGS. 13 and 14 and which comprises pinions 67
fixed to the bottom end of each spindle 61 and meshing with an
internal-toothing crown gear 69, the rotation of which causes
spontaneous rotation of the pinions 67 and thus of the spindles 61.
Rotation of the toothed crown gear 69 is obtained by means of a
pinion 70 fitted on a shaft 72 which is driven in rotation about
its own axis by means of a cylinder-piston actuator 74.
[0097] Set above the unit 39, and approximately aligned with the
end part 13C of the suction pipe 13, is a gripping member,
designated as a whole by 71, for gripping the tubular article that
is to be sewn. The gripping member comprises a pair of brackets 73
(see in particular FIGS. 1 to 3 and 5 and 6) which are mobile with
respect to one another with a movement of approach and recession
represented by the double-headed arrow f73 (see in particular FIGS.
5 and 6). Movement in the direction indicated by the arrow f73 is
obtained by a pair of cylinder-piston actuators associated to the
brackets 73 and carried by a structure which is in turn provided
with movements according to a horizontal axis X and a vertical axis
Y (see again in particular FIGS. 5 and 6). As will emerge clearly
hereinafter, the brackets 73 can be brought up to one another for
penetrating inside the suction pipe 13 and gripping the end edge of
the tubular article, and then tensioning it and carrying it to the
sewing machine for the subsequent sewing operation.
[0098] The structure that carries the member 71 for gripping the
tubular article is supported by a base structure 75, which is in
turn constrained to a fixed frame, for example the frame itself of
the knitting machine 3. The base structure 75 carries a pair of
bars 77 and 79 which are roughly rectilinear. The bar 77 is fixed
to a portion of metal section 81 which is mobile, as indicated by
the double-headed arrow f81, by means of cylinder-piston actuators
(not shown). In this way, the bar 77 can move away from and up to
the bar 79, which is, instead, fixed with respect to the base plate
75.
[0099] Underneath the fixed rectilinear bar 79, a comb-like
structure 83 is provided, which is illustrated in isolation and in
detail in FIG. 16. The comb-like structure 83 has a plurality of
teeth 85 and is made up of two portions 83A and 83B, which are
connected together and define an intermediate seat for sliding of a
cutting blade 87. The comb-like structure 83 is mobile as indicated
by the double-headed arrow f83 (see in particular FIG. 6) in a
direction orthogonal to the longitudinal development of the fixed
rectilinear bar 79. The cutting blade 87 housed inside the
comb-like structure 83 moves together with the comb-like structure
83, following the movement of the latter as indicated by the arrow
f83. The movement is obtained by cylinder-piston actuators or
equivalent actuators, designated by 89 in FIG. 6.
[0100] As may be seen in particular in FIG. 16, the cutting blade
87 is provided with a plurality of slots 87A which are inclined
with respect to the cutting edge 87B of the blade 87. Into the
slots 87A there insert pins 83C which are fixed to the portion 83B
of the comb-like structure 83. At one of its ends, the blade 87
extends to form an appendage 87C in which a slot 87D orthogonal to
the cutting edge 87B of the blade itself is made. In said slot 87D
there engages a slider 91 provided with a movement, parallel to the
cutting edge 87B, imparted by a cylinder-piston actuator or
equivalent actuator 93. The actuator 93 is carried by the base
plate 75, as may be seen in particular in FIG. 6. Thanks to the
slot 87D, the cutting blade 87 can move in a direction orthogonal
to the cutting edge 87B to follow the movement indicated by the
double-headed arrow f83 of the comb-like structure 83, all the time
maintaining mechanical connection with the actuator 93. Operation
of the actuator 93 causes a thrust in the direction indicated by
the arrow f87 (FIG. 16) on the blade 87, which consequently (thanks
to the arrangement of the pins 83C and of the inclined slots 87A)
will perform a movement with one component that is parallel and one
component that is orthogonal to the longitudinal development of the
comb-like structure 83. The function of this movement is, as will
be clarified in what follows, that of cutting the loops of the row
of stitches inside which the comb-like structure 83 is inserted for
carrying out sewing of the toe of the tubular article.
[0101] In the sewing area 37 there is moreover provided a sewing
machine, designated as a whole by 95, and illustrated in isolation
from the other mechanical members in FIG. 7. The sewing machine 95
has been omitted for reasons of clarity of representation in FIGS.
1, 2 and 3. The sewing machine has a sewing needle 96 and a mouth
for suction of the sewing thread 99. The reference number 101
designates the so-called "crochet", which imparts the raising and
lowering movement on the sewing thread for the latter, fed by the
thread bobbin, to be appropriately picked up by the sewing needle
96. The shape of the crochet 101 is provided purely by way of
example. The crochet may, for instance, also be of the rotating or
oscillating type. Likewise, the shape of the needle co-operating
with it may be different. The structure of the sewing machine 95 is
of a type in itself known to persons skilled in the art, and
consequently will not be described in greater detail herein. The
type of sewing performed by the needle 96 will in any case be
described in greater detail with reference to the operation of the
device.
[0102] The sewing machine 95 is provided with a sewing movement,
indicated by the arrow f95 in FIG. 4, imparted by an actuator,
designated as a whole by 97 again in FIG. 4.
[0103] Associated to the sewing machine 95 is a retention member
for withholding the tubular article after sewing of the toe in
order to carry out cutting of the part of fabric external to the
seam. The retention member is designated as a whole by 103, and its
position with respect to the other members of the device is
illustrated in FIG. 4, whilst its structure is illustrated in
detail in the perspective representation of FIG. 15.
[0104] The retention member 103 comprises a pair of bars 105, which
are substantially parallel to the movement of the sewing machine 95
and to the fixed bar 77 and mobile bar 79. The retention bars 105
are provided with a movement orthogonal to their own development in
the direction indicated by the double-headed arrow f105 in FIG. 15.
In this way, they can be brought up to one another for withholding
the article, or moved away from one another for releasing it. The
movement is imparted by cylinder-piston actuators (not shown)
housed in the structure of the retention member 103 fixed to the
sewing machine 95. Since the retention member 103 is fixed to the
sewing machine 95, it is also translated integrally with the sewing
machine when the latter performs the sewing movement in the
direction of the arrow f95. This enables the bars 105 to be brought
into alignment with the tubular article that is being sewn.
[0105] Finally, fixed to the sewing machine 95 is a system for
removal of the residue of yarn after the cutting operation has been
performed by the blade 87, said system being designated as a whole
by 107, and its position with respect to the other members of the
device being shown in FIG. 4. The structure of the removal system
107 in a possible embodiment is illustrated in the perspective
representation of FIG. 42. The removal system 107 is provided with
one or more brush members 109 which rotate about the axis of a
vertical shaft which is inserted into a suction mouth 111 through
which the residue of yarn separated from the tubular article by the
brush 109 is sucked in and removed.
[0106] Operation of the device so far described is illustrated in
what follows with particular reference to FIGS. 17 to 43.
[0107] FIG. 17 shows the end step of knitting of a tubular article
M by the needles 7 of the circular bed of needles of the circular
knitting machine 3. The tubular article is knitted starting from an
edge B1, which in FIG. 17 is in the bottom part and which in the
finished article will remain open. When the tubular article M is a
sock, said edge constitutes the elastic border of the sock. The
final knitting step envisages formation of an edge B2 which is
designed to be sewn to form the closed toe of the finished
product.
[0108] During formation, the tubular article M comes to set itself
in the space between the cylinder 5 of the needles 7 and the guide
element 15, and more precisely the part of said guide element that
projects with respect to the intake end 13A of the suction pipe 13.
In this step, the intermediate separator 19 set along the suction
pipe 13 is closed, and hence the jaws 21 and 22 grip the guide
element 15, holding it in position inside the suction pipe 13.
Preferably, at least one of the sets of sliders 31 and 32 is also
gripped, with the sliders engaging the guide element. The portion
of suction pipe between the intake end 13A and the intermediate
separator 19 is kept at a negative pressure through a suction mouth
14 set adjacent to the intermediate separator 19, on the intake
side of the suction pipe 13. The mouth 14 is connected to a suction
fan or the like (not shown).
[0109] The stem 15C which can be extracted from the guide element
15 has been previously pushed into its extracted position by means
of the air under pressure fed through the jaws of the separator
member 19. In this extracted position, the head 15E of the stem 15C
comes to be above the plane of the plates 59, which are opened to
enable passage of the head itself. Closing of the shaped plates 59
results in the stem 15C remaining engaged, through the hole 65
between the shaped plates 59, with the head 15E above the plates
themselves. This means that the stem 15C will remain in the
extracted position even in the absence of pressure inside the guide
element 15, and hence even when the jaws of the separator member 19
open. In this configuration, the stems 63 fixed to the plates 59
are up against the axis of the stem 15C and are at least partially
housed in a seat made in the stem below the head 15E of the latter,
in such a way as to reduce the radial encumbrance of the stems 63
for the reasons that will be clarified in what follows.
[0110] When the tubular article M has been completed by the
circular bed of needles 7 of the circular knitting machine 3, it is
unloaded from the needles and, as a result of the negative pressure
inside the suction pipe 13, is sucked in along the suction pipe 13
until it assumes the position shown in FIG. 18; i.e., until it
comes up against the intermediate separator 19. Movement of the
article M along the suction pipe 13 is guided by the guide element
15, the article M sliding in the free space between the inner wall
of the suction pipe 13 and the guide element 15. In order to enable
passage of the article M beyond the transverse surfaces on which
the sliders 31 and 32 act, the latter are closed and opened in an
alternating way, so that, during passage of the article M, only one
of the sets of sliders, either 31 or 32, is engaged with the guide
element 15. In this way, the tubular article M can pass beyond the
sections in which the sliders are set and can reach the position
illustrated in FIG. 18.
[0111] In order to cause the tubular article M to reach the output
end 13B of the suction pipe 13, in such a way that it bears upon
the wall formed by the shaped plates 59 in the position illustrated
in FIG. 19, the intermediate separator 19 is opened by moving the
jaws 21 and 22 away from one another. Suction through the mouth 14
can now be interrupted, whereas suction is activated through the
suction line connected, by means of the connection 57, to the
chamber 53 inside the mobile unit. 39. This latter suction can be
activated also in the previous step, i.e., the one represented in
FIG. 18.
[0112] In this way, the tubular article M reaches the position
represented in FIG. 19, in which it bears upon the wall formed by
the shaped plates 59 in their closed configuration. Also in this
case, movement of the tubular article M is guided by the guide
element 15, which extends as far as the shaped plates 59. The
sliders 33, which were previously closed for supporting the guide
element 15 during opening of the jaws of the intermediate separator
19, are opened to enable passage of the article. Opening of the
sliders 33 can be synchronized with a new movement of closure of
the intermediate separator 19, in such a way that the guide element
15 will be all the time properly withheld in a substantially
central position inside the suction pipe 13. Alternatively, lateral
support of the guide element may be obtained, even at least in
part, by means of engagement with the hole in the wall defined by
the plates 59.
[0113] The function of the subsequent steps is to extract the
tubular article M from the suction pipe 13 and turn it inside out
to carry out the closing operation whereby the end edge B2 of the
article is sewn to form the closed toe thereof.
[0114] For this purpose, as may be seen in FIG. 20 (which
represents the end area alone of the suction pipe 13), the plates
59 are displaced by means of the rotating spindles 61 so as to
displace radially outwards the stems 63 fixed to the plates 59.
[0115] Since both the plates 59 and the stems 63 are above the
output end 13B and hence outside the suction pipe 13, the movement
of divarication of the stems 63 can be extended up to the point
where the latter are brought into an external radial position
(shown in FIG. 20) outside the encumbrance defined by the edge of
the suction pipe 13. In this position, the portion of fabric of the
article M close to the edge B1 is tensioned in such a way that it
is substantially outside the encumbrance of the suction pipe
13.
[0116] Once the stems 63 have engaged the tubular article M, the
telescopically extensible stem 15C of the guide element 15 can be
retracted inside the portion 15B of the latter, thus reducing the
pressure inside the part 15B of the guide element 15. Retraction of
the stem is obtained by means of the effect of the extension spring
15D. In FIG. 20 the stem 15C is illustrated in its retracted
position.
[0117] By means of a vertical movement downwards, as indicated by
the arrow f39, of the unit 39, the stems 63 are brought into a
position where they are set alongside one another externally and
laterally with respect to the output end 13B of the suction pipe
13. The tubular article is still engaged by the stems 63 and has
thus followed the latter, enveloping externally the suction pipe 13
in the area that surrounds the output end 13B of the latter. The
lowering movement of the unit 39 proceeds until the stems 63 have
been completely released from the tubular article M (FIG. 22).
[0118] In order to extract the tubular article M completely from
inside the suction pipe 13 and turn it inside out by bringing it
onto the outer surface of the suction pipe 13, the pushers 47 are
pressed against the tubular article M (FIG. 23), and the unit 39 is
at this point further displaced downwards, as indicated by the
arrow f39 (FIG. 24). In this way, the further movement downwards,
as indicated by the arrow f39, of the mobile unit 39 causes the
tubular article M to be drawn along the outer surface of the
suction pipe 13 until the unit 39 reaches the position illustrated
in FIG. 24. In this position, the tubular article M is completely
on the outside of the suction pipe 13. It is also turned inside out
with respect to the configuration in which it was knitted by the
circular knitting machine 3. The pushers 47 can be divaricated
again to release the tubular article M, which remains in the
position illustrated in FIG. 25 thanks to the elasticity of the
article itself (and in particular of its initial edge B1), which
grips on the outer surface of the suction pipe 13. If the tubular
article M is particularly long, the stroke downwards of the unit 39
with the pushers 47 in the closed position can be repeated a number
of times, bringing the unit 39 each time back upwards after prior
opening of the pushers 47 to prevent the latter from drawing the
tubular article upwards again during the stroke upwards of the unit
39.
[0119] As may be seen in FIG. 24, the suction pipe 13 has two slits
13D which start from the output end 13B, i.e., from the edge of the
suction pipe 13, and which extend in a direction parallel to the
axis of the suction pipe for a certain stretch. The function of
these slits is to enable the brackets 73 to grip the tubular
article M and to slide it partially out of the suction pipe 13 for
closing the toe of the article by sewing. Before this operation is
carried out, however, the tubular article M may require angular
positioning.
[0120] In fact, the sewing line which is designed to close the toe
of the article must have a very precise orientation with respect to
the article itself, which normally presents pockets, namely
portions of fabric designed to form the heel area and the toe area
of the foot of the sock or stocking. The sewing line must assume an
extremely precise position with respect to these pockets of fabric.
In order to orient the tubular article properly before the sewing
operation, it is sufficient to provide, during knitting, marking of
the article, for instance by means of a few stitches of yarn of a
colour different from that of the yarn of the article. The marking
thus obtained can be detected by means of a photo-electric cell
(not shown) set in the proximity of the output end 13B of the
suction pipe 13. Appropriate angular orientation of the tubular
article M is at this point obtained by rotating, about its own
axis, the portion 13C of the suction pipe 13 by means of the
actuator 35. This rotation is the movement that brings the device
from the position of FIG. 24 to the position of FIG. 25. The two
figures differ, in fact, only as regards the different position of
the slits 13D made in the proximity of the output end 13D of the
suction pipe 13. The deviation in angular position between the two
figures represents the amount by which the portion 13C of the
suction pipe 13 is rotated with respect to the remaining part of
the pipe itself in order to bring the tubular article into the
correct angular position.
[0121] During this step of angular positioning, or in any case at
an appropriate instant, the unit 39 is brought back upwards until
it reaches the position illustrated in FIG. 26, the pushers 47
remaining in their retracted position, i.e., not in contact with
the tubular article, during said movement upwards.
[0122] Once the unit 39 has reached the top position illustrated in
FIG. 26, the pushers are closed again to press the tubular article
M against the outer surface of the suction pipe 13 in the proximity
of the output end 13B of the latter. Once the tubular article M has
been engaged again by pressing it against the outer surface of the
portion 13C of the suction pipe 13, the portion 13C can be rotated
again so as to bring the slits 13D into their original position,
namely on a plane which contains the axis of the portion 13C of the
suction pipe and is orthogonal to the plane of FIG. 26. This
movement of rotation of the portion 13C of the suction pipe 13,
again obtained by means of the actuator 35, does not cause an
angular movement of the tubular article M, in so far as the latter
is withheld by the pushers 47, which are advantageously coated with
a material having a high coefficient of friction. In this way, the
portion 13C of the suction pipe 13 rotates inside the tubular
article M in a sliding way, i.e., sliding on the inner surface of
the latter.
[0123] In the configuration of FIG. 26, the tubular article M is in
the correct angular position for the subsequent sewing operation,
and can therefore be picked up by the brackets 73 of the gripping
member 71. The brackets 73, which are brought up to one another,
are for this purpose lowered until they move inside the suction
pipe 13, into the position shown in FIG. 27, which represents a
longitudinal cross section of the suction pipe 13 according to a
plane orthogonal to the one represented in FIG. 26. The brackets 73
thus lie on a plane containing the axis A of the portion 13C of the
suction pipe 13, on which also the slits 13D lie. In this way,
divarication of the brackets 73, as indicated by the arrow f73 of
FIG. 27, is enabled for tensioning the edge B2 of the tubular
article M and thus bringing the two flaps of the edge to come close
to one another. The movement of divarication of the brackets 73 is
combined with a movement of lifting-up of the brackets, which thus
reach their final position, illustrated in FIG. 28. In the end
phase of the raising movement of the brackets 73, the pushers 47
can be brought up to the suction pipe 13 again for withholding the
tubular article M and thus causing longitudinal tensioning
thereof.
[0124] In this position, the edge B2 of the tubular article M has
been stretched or tensioned by means of the brackets 73 in such a
way that the two flaps of the edge have been aligned to one
another. The brackets 73 have been brought into a vertical position
such that their bottom ends are slightly above the rectilinear bars
77 and 79. The latter can thus be brought up to one another to grip
the tubular article M in an appropriate position of the edge B2.
This is schematically represented in FIG. 29, which shows a
longitudinal cross section according to a plane orthogonal to that
of FIG. 28. The rectilinear bar 77 has been brought up to the fixed
bar 79. In FIG. 28, L1 and L2 designate the two flaps of the edge
B2 that have been brought close to one another as a result of the
tensioning of the edge B2 performed by the brackets 73 of the
gripping member 71. The article can be tensioned by means of a
slight movement downwards of the unit 39 with the pushers 47.
[0125] FIG. 29A is a schematic enlargement of the area in which the
flaps of fabric L1 and L2 forming the edge of the tubular article
that is to be closed can be seen. As shown in the schematic section
of the fabric, the latter presents a series of rows X2 set above
the bars 77 and 79, some of these rows being made with a yarn
thicker than that of the other rows. Said thicker rows form a
portion of fabric of greater thickness, which is brought to bear
upon the bars 77, 79 set alongside one another. The bars 77, 79 do
not necessarily have to be pressed against the fabric, which,
instead, is appropriately left free to slide so as to be tensioned
transversely. Retention in the longitudinal direction is guaranteed
by the fact that the portion of fabric of greater thickness
obtained with the thicker yarn, designated by FG in FIG. 29A, bears
upon the bars 77, 79. The portion of the tubular article made up of
the rows X2 will be removed in the subsequent cutting operation,
and is consequently normally produced with a yarn of poorer quality
than the yarn of the remaining part of the tubular article M.
[0126] During the sewing operation, the edge formed by the rows X2
may be kept raised by means of suction through a suction mouth
associated to the sewing machine 95 and designated, as a whole by
102 in FIGS. 33 and 34.
[0127] With a movement in the direction indicated by the arrow f83,
the comb-like structure 83 is at this point pushed towards the
tubular article M until the teeth 85 of the comb-like structure 83
penetrate inside the stitches or loops of the row that is set
facing the comb-like structure 83, namely the row that is directly
beneath the rectilinear bars 77 and 79. As will be described in
greater detail with reference to the diagrams of FIG. 44 and of the
following figures, and as may be seen in the diagram of FIG. 29A,
the loops of this row (designated by X1) have a greater length than
the remaining loops of the article in order to enable convenient
insertion of the teeth 85 of the comb-like structure 83.
[0128] The movement in the direction indicated by the arrow f83 of
the comb-like structure 83 is controlled by the actuators 89
described previously (see FIG. 6) and not illustrated, for reasons
of clarity, in FIG. 29. The closing movement of the rectilinear
bars 77 and 79 and the subsequent movement of the comb-like
structure 83 are represented in the sequence of FIGS. 30 to 32,
which show the aforesaid movements in schematic plan views.
[0129] Once the teeth 85 of the comb-like structure 83 have
penetrated the individual loops of the respective row in the
tubular article M, the mobile rectilinear bar 77 can be retracted
to enable insertion of the members of the sewing machine 95, which
performs sewing along the loops of the row of stitches underneath
the row inside which the teeth 85 of the comb-like structure 83
have penetrated. The sewing operations are schematically
illustrated in FIG. 33.
[0130] FIG. 33 shows the needle 96 of the sewing machine 95, the
mouth 99, and the crochet 101. Also visible is the comb-like
structure 83, which is inserted inside the corresponding row of
stitches or loops of the tubular product M. The sewing area is
shown enlarged in FIG. 34. Clearly visible in the latter figure is
how the comb-like structure 83 and the corresponding teeth 85 are
made up of the two portions 83A and 83B (shown separate from one
another in the perspective view of FIG. 16), which are connected
together and between which the blade 87 is set, said blade, in this
configuration, being in a retracted position, namely a position set
back with respect to the teeth 85.
[0131] Movement of the members of the sewing machine, and in
particular of the needle 96 and the crochet 101 which feeds the
sewing thread F, is shown in FIG. 35. In this example of
embodiment, the needle 96 is a so-called piston needle, i.e., a
needle provided with an opening and closing member 96A. A needle of
this kind is in itself known from the state of the art, in
particular from the prior patents cited in the introductory part of
the present description. It is, however, possible to use also other
types of needles and/or crochets. For example latch needles or eye
needles may be used. The sequence of the sewing operations may be
clearly seen in FIG. 35 and is in itself known for other types of
applications; consequently, no detailed description is required
herein.
[0132] It should however be noted that, for the reasons that will
emerge more clearly from the description of FIG. 44 and subsequent
figures, the pitch of the seam made by the sewing machine 95 with
the needle 96 is smaller than the pitch of the comb-like structure
83 and of its teeth 85, i.e., smaller than the pitch of the loops
of the row X1. In particular, it is possible to envisage that the
pitch of the seam will be equal to one half or to one third of the
pitch of the loops of the row X1, and hence of the teeth 85 of the
comb-like structure 83.
[0133] FIGS. 36, 37 and 38 show the subsequent step of cutting of
the loops of the row X2, inside which the teeth 85 of the comb-like
structure 83 have been inserted. Before carrying out this cutting
operation, the flaps L1 and L2 of the tubular article M, which are
by now joined together by the seam designated by C in FIGS. 36 to
38, are gripped and withheld by the retention bars 105 of the
retention member 103 carried by the sewing machine 95 which has
made the seam C. This makes it possible to withhold the tubular
article M even after the cutting operation has been performed.
Cutting is performed by moving the blade 87 housed inside the
comb-like structure 83 so as to bring it from the position of FIG.
36 to the position of FIG. 37. Thanks to this movement, the blade
87 cuts all the loops of the row X2 inside which the teeth 85 of
the comb-like structure 83 were previously inserted.
[0134] At this point, the comb-like structure 83 can be moved away
from the article to reach the position shown in FIG. 38, whilst the
tubular article M is withheld by the retention bars 105 provided
for this purpose and previously brought up to one another. The
residue of cut yarn above the seam C is removed by the removal
system 107, which in FIG. 39 is schematically represented by a
brush with a horizontal axis, parallel to the bars 105, but which
may actually have the configuration shown in FIG. 40. The enlarged
representation of FIG. 41 shows the action mechanism of the brush
109, in this case with a vertical axis, for removal of the residue
of yarn, designated by FR in the enlarged representation of FIG.
41.
[0135] Once said sewing, cutting and yarn-residue-removal
operations have been completed, the article M can be removed from
the device, after the article has been turned inside out again to
assume its final configuration corresponding to the one in which it
was produced by the circular knitting machine 3. For this purpose,
reverse operations are performed with respect to the ones
previously carried out for turning the article inside out by means
of the movement of the unit 39 and the action of the sliders 47.
Negative pressure is at this point applied inside the suction pipe
13 through a suction mouth 16 (FIG. 43) in such a way that the
article, with its toe closed by the seam C, is sucked through the
mouth 16 and is removed from the device.
[0136] Removal is facilitated by the movement of the part 15B of
the guide element 15 with respect to the part 15A, about the hinge
axis 17, so that the part 15B of the guide element comes up against
the inner wall of the suction pipe 13 on the opposite side with
respect to the one where the suction mouth 16 is set, leaving a
wider passage for transit of the sewn tubular article M towards the
suction mouth 16.
[0137] Once the above operations have been completed, the device
returns to the configuration represented in FIG. 17 for sewing of a
subsequent tubular article M, which, in the meantime, has started
its formation on the circular knitting machine 3.
[0138] FIGS. 44, 45 and 46 are detailed illustrations of the
textile structure of the edge part B2 of the tubular article M for
enabling closing by means of the seam described previously. FIG. 44
illustrates one portion of the edge area B2 of the tubular article.
The reference X1 designates the row of stitches or loops BX1 of
greater length within which the teeth 85 of the comb-like structure
83 insert. As is clearly shown in FIG. 44, said loops BX1 have a
greater length than the remaining loops BX underneath, which are
the ones forming the body of the tubular article.
[0139] Above the row X1 there is a plurality of rows X2 made with
the same yarn--or with a yarn of poorer quality--as the one forming
the underlying rows of loops or stitches BX. The loops or stitches
of the rows X2 may have the same size as the loops BX.
[0140] Once again in FIG. 44, C designates the seam formed by the
sewing machine. As may be seen in the figure, the seam C is made in
a position corresponding to the row of stitches X3 set beneath the
row of stitches X1. In other words, the seam C is made on the row
of stitches or loops adjacent to the row where the teeth 85 of the
comb-like structure 83 are inserted, which represents a substantial
difference as compared to normal seams performed with linking
machines.
[0141] Furthermore, the pitch of the seam C is greater than the
pitch of the loops or stitches of the row X3, and hence of the row
X1 and of any other row of the article. Also this constitutes a
substantial difference as compared to the normal process of linking
of tubular articles, where the seam has exactly the same pitch as
that of the stitches or loops that undergo linking. The pitch of
the seam C, which is smaller than the pitch of the loops, is chosen
in such a way that any possible accidental faulty gripping of the
loops by the teeth 85 of the comb-like structure 83 does not have
any unfavourable effect on the final result of the sewing
operation. In fact, even if two adjacent loops were to be taken up
on the same tooth 85 of the comb-like structure 83, the seam C
(which has a smaller pitch) would even so grip the loops, thus
enabling perfect sewing of the article to be achieved. Instead, in
a traditional linking machine, faulty hooking of the loops to be
sewn on the hooks of the machine results in an irreparable defect
in the product, which consequently must be rejected.
[0142] Basically, the loops of the row X3 are sewn together by
joining the loops of the flap L1 to corresponding loops of the flap
L2 by means of stitch formed by a sewing thread forming the seam C.
Said sewing thread forms a chain of stitches, in which between the
stitches that join the two flaps there are interspersed stitches
that do not join the two flaps of the tubular article.
[0143] FIG. 45 shows two portions of the row of stitches or loops
X3 on which sewing is performed. The isolated representation of
this individual row of stitches or loops clearly shows the sewing
technique, performed with a pitch greater than the pitch of the
loops. The references XC1 and XC2 designate the loops formed by the
sewing thread. In greater detail, the loops XC1 are the ones that
engage the yarn forming the loops of both of the flaps set
alongside one another of the edge B1 of the article M, whilst XC2
designates the loops formed by the sewing yarn which do not join
the two flaps. The seam is, in this example, a single-chain seam,
but different embodiments are not to be ruled out.
[0144] FIG. 46 is again a representation of the article in the
sewing area, in a way similar to the one represented in FIG. 44,
but after the cutting operation has been performed by the blade 47.
As mentioned previously, cutting is performed on the row X1, namely
on the row inside which the teeth 85 of the comb-like structure are
inserted. It is precisely this row of stitches or loops having a
greater length that is interrupted by cutting, unlike what happens
in traditional linking machines, where the row of stitches hooked
on the hooks of the linking machine is the one on which sewing is
performed; instead, in the present case, cutting is performed on
the adjacent row external to the seam, namely the row set on the
opposite side of the row of hooks with respect to the side where
the body of the tubular article is set.
[0145] FIGS. 44 and 46 schematically represent that the first of
the rows X2, i.e., the one immediately after the row X1, is made
with a yarn FG of a larger section, which can possibly be elastic.
Instead of the first of the rows X2, the immediately subsequent row
can be made with the yarn of larger section; or else, even more
than one row may be made with a yarn of larger section. The
function of this yarn has been illustrated previously with
reference to the step of preparation of the article for the sewing
operation.
[0146] As mentioned previously, the rows of stitches in a normal
tubular article develop helically. In order to obtain even more
precise and neat sewing or linking of the toe, according to an
improved embodiment of the invention it is possible to envisage
that the rows of stitches involved in the seam for joining the
flaps forming the toe will be circular, instead of helical. This is
obtained by interrupting the yarn that forms the fabric. FIG. 47 is
a schematic representation of one portion of the rows X1, X2 and X3
in the area where the yarn is interrupted. In this embodiment, each
row is formed by yarn that has a beginning and an end, which are
designated (for each row) by I1, I2, I3, and F1, F2 and F3. The
perfectly circular rows of stitches X1, X2 and X3 that are thus
obtained enable alignment along the comb-like structure 83 without
any deformation and convenient insertion of the teeth 85 into the
individual loops of the row X1. Likewise, the stitches of the seam
C will involve only the loops of the row X3 and will not interfere
with the loops of the adjacent rows.
[0147] With reference to the above figures, a complex device has
been illustrated, which, combined with the knitting machine 3,
enables complete automation of the production cycle to obtain at
output a complete tubular article with the toe that has been sewn
or linked. However, the invention can be implemented also in
simpler forms, for example by means of a semi-automatic or almost
completely manual device, which, in any case, enables closing of
the toe with an operation which is much more convenient than
traditional linking, at the same time maintaining a high quality of
the finished product.
[0148] FIGS. 48 to 53 show a possible example of embodiment of a
substantially manual device, in which the operator inserts the
tubular articles manually for closing the toes. The device
comprises an insertion guide, designated as a whole by 201 and made
in the form of a guillotine, with two parallel bars that define a
channel for insertion of the tubular articles. The latter are
designated by M. The insertion guide 201 is divided into three
portions. A first portion 201A is fixed with respect to the
load-bearing structure 203 of the device. The second portion 201B
is mobile, for example by means of a pedal control by the action of
an actuator 205, so as to approach a comb-like structure that
performs the same function as the comb-like structure 83 previously
described and here designated by 207.
[0149] The two positions that the portion 201B of the guide 201 may
assume can be seen in FIGS. 48 and 49. In FIG. 48, the guide
portion 201B is aligned to the guide portion 201A, whilst in FIG.
49 the portion 201B is brought up to the comb-like structure.
[0150] The third portion 201C of the guide 201 is fixed with
respect to the structure of the device and is in a position whereby
it is aligned to the portion 201B when the latter is in the
position of FIG. 49.
[0151] The comb-like structure 207 in this case is made up of a
plurality of rigid components 207A which are joined together in a
flexible way and are fixed to a chain 209 to form a comb-like
structure in the form of a closed track run over two wheels 211,
one of which is motor-driven.
[0152] The reference number 213 designates, as a whole, a sewing
machine, similar to the sewing machine 95 previously described,
which is illustrated in isolation in FIG. 50 and is illustrated, in
combination with a portion of the comb-like structure, with one of
the wheels 211 in FIG. 51. The sewing machine 213 comprises a
needle 215 and a crochet 217 of the oscillating type.
[0153] As may be seen in particular in the enlarged detail of FIG.
52, the comb-like structure presents a slit that develops within
the teeth 208 of the comb-like structure 207, within which a
disk-shaped element 219 may penetrate, said disk-shaped element 219
being supported by a shaft 221 driven in rotation by a motor
223.
[0154] At the sewing area, as may be seen in the plan view of FIG.
53, underneath the comb-like structure 207 there is a guide profile
225 with an initial rectilinear portion 225A and a subsequent
curvilinear portion 225B. The latter is roughly parallel to the
edge of a wheel 227 which has an axis of rotation orthogonal to the
plane of FIG. 53 and is driven by a motor (not illustrated). The
wheel 227 is located underneath the disk-shaped blade 219 and has
the function of drawing along the tubular article during the
cutting operation, as will be explained in greater detail in what
follows.
[0155] The device so far described operates as illustrated
hereinafter. The individual articles are inserted into the portion
201A of the guide 201. They are pushed manually as far as the
portion 201B of the guide 201. At this point, the operator tensions
the article and, by means of a special control, causes displacement
of the guide portion 210B against the comb-like structure in such a
way that the teeth 208 of the latter insert into the loops of the
article. The article has a textile structure equivalent to the one
described previously, with rows X1, X2 and X3 of the sizes
described previously and for the same purposes. Once the comb-like
structure 207 has engaged the article, it advances in the direction
indicated by the arrow f207 and carries the article towards the
sewing machine. Here the operations of sewing and cutting by means
of the disk-shaped blade 219 are performed. The residue of yarn is
then eliminated by means of the brush 231.
[0156] FIG. 54 shows a different embodiment of a device,
generically designated by 301, for semi-automatic sewing of tubular
articles. Said device comprises means for positioning and
tensioning tubular articles, generically designated by 303, as well
as a sewing assembly, generically designated by 305 and similar to
the device of FIGS. 48 to 53.
[0157] The positioning and tensioning means 303 comprise a circular
table 307 which turns on a fixed shaft 309. The circular rotary
table 307 carries a plurality of suction pipes 311 connected at the
rear (in a way not illustrated) to a suction system. The suction
pipes 311 perform a function similar to the one performed by the
end part 13C of the suction pipe 13 previously described. They
present end slits 311, within which brackets 313, which are
equivalent to the brackets 73 described with reference to the first
example of embodiment and are associated to the unit 305,
insert.
[0158] The fixed shaft 309 carries a plurality of guides 315 (four,
in the example illustrated) with corresponding actuators 317 which
control the movement of translation, parallel to the shaft 309 and
to the suction pipes 311, of corresponding rings 319, each of which
carries a plurality of pushers 321 equivalent to the pushers 47.
The guides 315 with the corresponding rings 319 and the pushers 47
define four stations through which each of the suction pipes 311
passes for proper positioning of the tubular article that is to be
sewn.
[0159] Operation of the device of FIG. 54 is described in what
follows. Each tubular article is inserted with its end edge into
the suction pipe 311 which is in the position 311X. The operator
inserts the end edge of the article into the suction pipe, leaving
the elastic initial edge or border of the article outside the pipe,
in such a way that it envelops the pipe. The rotary table 307
rotates by one step to bring the suction pipe on which the tubular
article has been fitted into the next station, where by means of an
axial movement of the respective ring 319 parallel to the pipe and
by operating the pushers 321, the tubular article is turned inside
out onto the outside of the suction pipe, in a way similar to what
was illustrated with reference to FIG. 24 for the previous example
of embodiment.
[0160] A subsequent rotation by one step takes the suction pipe
into the next station where, with modalities similar to the ones
described with reference to FIGS. 24 and 26, orientation of the
tubular article is performed.
[0161] A further rotation by one step brings the suction pipe into
alignment with the brackets 313, which pick up the tubular article
and insert it into the guillotine-like guide of the unit 305. From
this position, operation is similar to the one described for the
device of FIGS. 48 to 53, with the exception that the tubular
article remains engaged with its elastic edge or border outside the
suction pipe, which is displaced by one further step by rotation of
the rotary table 307 during the sewing operation or at the end
thereof.
[0162] The last ring 319 with the corresponding pushers 321 is used
for turning the tubular article inside out again, said tubular
article being then extracted by suction through the pipe, in a way
altogether similar to what was described with reference to the
first example of embodiment.
[0163] The device of FIG. 54 thus operates in a semi-automatic way,
in so far as the only manual operation consists in fitting the
tubular articles on the individual suction pipes, whereas the
entire subsequent processing cycle is carried out
automatically.
[0164] The system for turning the article inside out may also
present a different configuration. For example, shaped rubber
wheels may be used which co-operate with the surfaces of the
suction pipes 311, instead of the rings 319 and pushers 311. This
applies in particular to the first station, in which the article is
turned inside out for the first time onto the outside of the
suction pipe.
[0165] It is understood that the drawings only illustrate a
possible embodiment of the invention given purely to provide a
practical demonstration of said invention, which may vary in its
embodiments and arrangements without thereby departing from the
scope of the underlying idea. The possible presence of reference
numbers in the attached claims has the sole purpose of facilitating
reading thereof in the light of the foregoing description and of
the annexed drawings and in no way limits the scope of protection
defined in the claims.
* * * * *