Note: Descriptions are shown in the official language in which they were submitted.
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NEEDLE MOTION
Background of the invention
The present invention relates to a needle motion for a double-bed knitting
machine, such as a double-cylinder circular knitting machine, two-needle bed
or
four-needle bed flat knitting machines, or similar machines, designed in
particular for an automated production of seamless knitted outerwear and
underwear of the tubular type, for example trousers, panties, leggings,
undershirts, T-shirts, pull-overs, and the 'like, with a possibility of a
reversible
and a links-links structure of the knitted fabric in the rib-top area.
The invention further concerns a knitting machine as well as a knitting
needle.
Description of the prior art
A highly and fully automated production is an essential requirement for
every modern production process. In the case of the products made of the
knitted fabric, the field of textile production is, as a rule, characterized
by
requirements for a large extent of the finishing operations realised by
sewing,
which is, above all, case of the underwear. This introduces not only a
considerable amount of a manual work on the finished product and an increase
in the production costs, but also certain devaluation of the manufacture
qualities
of the knitted fabric in the seam area. Seamless knitted underwear with
elastic
rib tops in a reversible structure (wale) does not yet exist in practice,
although
such underwear seems to be an ideal one in terms of utility value.
Knitting machines are known designed for an automated production of
knitted goods, in which three tubes are being interconnected. This is for
example the case of trousers, panties, leggings, undershirts, T-shirts, pull-
overs, and the like. A very important property of these types of knitting
machines is among others a capability of realising the knitted fabric, above
all in
the area of waist opening and leg openings, in the reversible structure (so
called
wale) in order to prevent the known and undesirable twisting of jersey knitted
fabric. ,
One of these knitting machines is the two-needle bed flat knitting
machine with the needle beds arranged in the form of "V". These knitting
machines, for making loops, make use of knitting needles with actuation
pistons, by virtue of which a transfer of the loops of the knitted fabric to
the
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opposite needle bed is made possible. The main drawback of these knitting
machines is that it is necessary, when knitting a tube in a reversible or a
links-
links structure of the knitted fabric, to establish the purl loop in the first
instance
on the opposite needle bed and then to transfer it to the needle bed on which
the jersey loops of the same course of the knitted fabric are being
established.
This leads not only to an inadequate lengthening of the production cycle, but
also a constructional complexity which results in that it is possible, on
these
knitting machines, to make knitted goods in the reversible structure, or
eventually in the links-links structure, up to only 9(E) pitch of the knitted
fabric,
which is, in case of underwear, absolutely insufficient. The type of the
needle
motion being the source of the above-mentioned drawbacks.
Another known type of the knitting machines intended for the mentioned
knitted goods is the four-needle bed flat knitting machine with the knitting
needle beds arranged in the form of "X", with a needle motion that is
basically
identical as the needle motion of two-needle bed knitting machines with the
needle beds arranged in the form of "V". An advantage of these types of four-
needle bed flat knitting machines in comparison with the two-needle bed
knitting
machines with the needle beds arranged in the form of "V" rests in the
possibility of producing knitted goods up to the 18(E) pitch of the knitted
fabric.
For the underwear such as panties, T-shirts, or similar, this is, however,
still
insufficient. Moreover, it is obvious that the four-needle bed flat knitting
machines are mechanically practically twice as complicated as the two-
needle bed flat knitting machines. As regards the duration of the production
cycle, the four-needle bed flat knitting machines are equally unfavourable as
the
two-needle bed knitting machines, as the time needed for the transfer of the
purl
loops onto the opposite needles represents an operating delay.
Another type of knitting machines of the mentioned category are also the
four-needle bed flat knitting machines with the knitting needle beds arranged
in
the form of "X", but making use of double hook needles known from double-
cylinder small diameter knitting machines. A great advantage of this category
of
machines is the fact that the manufacturing technology of the double hook
needles was mastered up to the thickness of the needle stem of 0.4 mm, what
makes it possible to construct the knitting machines up to the 24(E) pitch.
This
significantly broadens the range of the knitted goods that might be made on
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these knitting machines. However, the complexity of the flat knitting machines
of
this category is exceptional. Besides the mechanisms for actuation of the
double head knitting needles, it is another additional auxiliary special
mechanism what is necessary for ensuring the transfer of the purl loop from
the
hook for making the purl loops to the hook for making the jersey loops at the
moment of switching the knitting needle from the needle bed for making the
purl
loops to the needle bed in which the jersey loops are being made. Another
drawback being also a significantly restricted range of the density of the
knitted
fabric in order to be able to transfer safely the purl loop into the hook for
making
the jersey loops.
Double-cylinder knitting machines of the state of the art using double-
head latch needles are known inter alia from US-A-2003/0101775, US-B-
6,220,061, US-A-5,718,128; US-A-4,879,884.
Summary of the invention
According to one aspect the invention provides improvements to the
current state of the art by providing a new needle as well as a new needle
motion enabling designing of knitting machines for making different types of
tubular seamless knitted goods in a links-links or a reversible structure in a
fully
automated production cycle without any considerable restrictions of the pitch
of
the knitted fabric. According to some embodiments, the goal of the invention
is
also to enable a simplification of the constructional arrangement of the
knitting
machine and to no small extent also improving the cost-effectiveness of the
production of the mentioned category of the knitted goods by removing the
finishing operations realised by sewing and by reduction of the idle time in
the
production cycle.
These goals are achieved by means of a needle motion according to the
invention, the substance of which rests in that the needle motion comprises
knitting needles having a double knitting spring beard, i.e. a so-called
spring
beard or spring hook at each end of a stem, the knitting hook or beard at each
end of the stem forming an elastic buckle terminating at a tip, whereas on the
stem, in the vicinity of the tips of each elastic buckle of the hook or beard,
there
are provided corresponding curved portions with a convexity facing towards the
respective tip. Said curved portions are provided with respective recesses for
the tip of the elastic buckle or beard, and with respective recesses for the
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projection of a slider or transfer jack used as an actuation element to move
the
needle. According the invention, therefore, the knitting needle is a so-called
spring-beard needle or bearded needle, which is characteristically provided
with
a double head, i.e. with a beard or spring at both ends of the needle stem.
A main advantage of the needle motion according to the invention in
comparison with the devices known from the state of the art and using a double
hook knitting needle, i.e. a double latch needle, is that at the switching of
the
knitting needle from one needle bed to another in case of a flat knitting
machine, or from one needle cylinder to another needle cylinder in case of a
circular knitting machine, respectively, no automatic knock-over of the loop
of
the knitted fabric situated on the stem of the knitting needle takes place, in
such
a manner as it is in case of the known double hook needle. Therefore, the
knitting machine does not need a special mechanism for hindering the knock-
over of the loop at the time when the knitting needle switches from one needle
bed to the other needle bed of the knitting machine without forming a new
loop.
On the one hand this considerably simplifies the construction of the knitting
machine, and on the other it also considerably speeds up the production cycle,
because the operation such as for example establishing of a loop and a
subsequent switching of the knitting needle without forming a new loop can
simply be carried out by a single working motion of the carriage of the
knitting
cam system. The advantages of the needle motion according to the invention
are even more significant in comparison with the knitting needles with
actuation
pistons, because, by means of knitting needles with actuation pistons, it is
not
possible to provide for a knitting machine having such a mechanical delicacy
as
in the case of the needle motion according to the invention.
According to some preferred embodiments, every knitting needle is
provided with a pair of actuation sliders, one slider being arranged in each
needle bed. On each of the actuation sliders are arranged at least a bearing
surface for the hook of the knitting needle and a projection for hitching the
stem
of the knitting needle at the recess provided at the level of the above
mentioned
curved portion of the needle stem. In some embodiments, each slider includes a
bevel or nose for realisation of a spontaneous deviation of the actuation
slider, a
pivot point for deviation of the slider, at least one rigid butt for
controlling an
axial translation of the slider. According to some preferred embodiments, each
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slider is also provided with a butt for controlling an oscillatory deviation
of the
actuation slider, which is of advantage in the case if no links-links patterns
are
needed to be made in the knitted fabric, for reasons of mechanical simplicity.
In some embodiments, the actuation sliders are provided with an an
auxiliary actuation slider with a working butt, said auxiliary actuation
slider being
swingingly attached to the actuation slider by means of a joint. In such
embodiment, when it is necessary to realise a plurality of independent working
paths for a rigid working butt of the actuation slider, it is possible to
easily
achieve a transfer between the respective working paths for the rigid butt by
means of a butt on the auxiliary actuation slider.
If both of the pair of the actuation sliders are of the same type, such an
embodiment is advantageous in the case when it is necessary to realise
identical or similar working paths of the knitting needles in both needle beds
or
needle cylinders.
If each of the pair of the actuation sliders is of a different type, this is
advantageous especially in the case when in one of the needle beds, or in one
of the needle cylinders, it is sufficient to realise simplified working paths
of the
knitting needles.
For making links-links and cardigan patterns in the knitted fabric, it is of
advantage if a patterning device is assigned to always at least one of both
actuation sliders.
An application of the needle motion according to the invention on the
two-needle bed flat knitting machine is of advantage above all thanks to the
possibility of achieving a high level of the pitch of the gauge (up to 34 E).
An application of the needle motion according to the invention on the
four-needle bed knitting machine is of advantage above all thanks to an
overall
simplification of the construction of the machine, as the switching of the
knitting
needles from needle bed to needle bed is substantially simplified in the case
when a simultaneous establishing of the loop is not required. It further
brings a
considerable time saving in the working cycle of the machine, because for
establishing of a loop and a subsequent switching of the knitting needle from
needle bed to needle bed without forming a new loop the same motion of the
carriage of the knitting cam system can be used.
An application of the needle motion according to the invention on the
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double-cylinder small diameter or large diameter knitting machine is of
advantage above all thanks to the fact that no mutually synchronized motion of
the actuation sliders in the upper and lower needle cylinder is necessary, and
that the patterning possibilities of the knitting machine are broadened in
comparison with the double hook needle.
According to a further aspect, the invention provides a knitting machine
including at least two needle beds, a plurality of knitting needles and
corresponding actuating sliders in each needle bed, for controlling knitting
movements and transfer movements of said needles from one needle bed to
the other, wherein each needle includes a stem and two knitting needle heads
(3, 4) arranged at opposed ends of said stem; wherein:
- each needle head includes a spring hook terminating at a tip;
- the stem of said needles is provided with a pair of curved stem portions,
each curved portion being arranged in the vicinity of a corresponding one
of said tips, said curved stem portions having a convexity facing towards
the respective tip;
- each curved stem portion is provided with a first recess) for the respective
tip and with a second recess for engagement by a projection of said
actuating sliders.
According to still a further aspect, the invention provides a knitting needle
including a stem and two knitting needle heads arranged at opposed ends of
said stem wherein: each needle head includes a spring hook terminating at a
tip; the stem of said needle is provided with a pair of curved stem portions,
each
curved portion being arranged in the vicinity of a corresponding one of said
tips,
said curved stem portions having a convexity facing towards the respective
tip;
and each curved stem portion is provided with a first recess for the
respective
tip and with a second recess for engagement by an actuation slider.
Brief description of the drawings
The invention will now be described and explained with the aid of
following drawings. In the drawings:
Figs. 1 and 1 a show a front view and a side view respectively of a double
head knitting needle, i.e. a double-head bearded (or spring beard) needle
according to the invention, with hooks provided at both ends of a central
stem;
Figs.1 b and 1 c show enlargements of details of Figs. 1 and 1 a;
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Fig. 2 shows a side view of the complete needle motion in its simplified
variant;
Fig. 3 shows a part of the simplified variant with an actuation slider in an
enlarged scale;
Fig. 4 shows one of the possible variants of the actuation sliders allowing
making of links-links or reversible and cardigan patterns;
Figs. 5a - 5e show the steps of the exemplary realisation of a jersey loop;
Figs. 6a - 6e show the steps of switching the knitting needle from one
needle bed to another without forming a new loop;
Figs.7a-7e show enlarged details of Figs.5a-5e; and
Figs. 8a-8e show enlarged details of Figs. 6a-6e.
Detailed description of embodiments of the invention
Figure 1 shows a knitting needle according to the invention, which can be
used in the needle motion according to the invention. The knitting needle 1
includes a stem 2 having opposedly arranged knitting heads, each including a
respective knitting hook or beard 3, 4. Each hook or beard is shaped
essentially
in a fashion similar to known so-called "spring beard needles" or "bearded
needles" or simply "spring needies". Each hook or beard extends therefore
forming an elastic buckle or spring buckle 5, 6 terminating at a tip 7, 8. The
hook 1 is therefore a so-called "spring beard needle" or "bearded needle",
which however, contrary to the bearded needles of the prior art, is double,
i.e. is
provided with hooks at both ends of the stem. The needle can be formed of one
piece of spring steel forming the stem 2 and the two long terminal hooks or
beards 3, 4.
On the stem 2 of the knitting needle 1, reaching the position reached by
each tip 7, 8 of the elastic buckles 5, 6 when the book is closed by elastic
deformation thereof, curved stem portions 9, 10 are provided. Each said curved
portion has a convexity facing the tip of the corresponding spring hook. In
each
curved portion 9, 10 of the stem 2there are arranged recesses 11, 12 or slits
into which the tips 7, 8 of the elastic buckles 5, 6 of the knitting hooks 3,
4 can
penetrate. Further recesses 13, 14 are also provided in said curved portions,
for
engagement by projections 17, 25 of corresponding actuation sliders 15, 23.
The knitting needle 1 is therefore symmetrical with respect to its transversal
axis
X-X.
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The needle motion generally comprises a knitting needle 1, and for each
knitting needle 1 at least a pair of actuation sliders 15, 23, which may be
identical or of a different construction. Figure 3 shows one type of these
possible constructions. An actuation slider 15, shown in figure 3 in a larger
scale than in figure 2, has a bearing surface 16 for the adjacent hook 3, 4 of
the
knitting needle 1 and a projection 17 for locking into the respective recess
13,
14 in the curved portion 9, 10 of the knitting needle 1. The actuation slider
15 is
further provided with a butt 19 for generating an axial translation, i.e. a
sliding
movement of the slider and along a sliding recess provided in the needle bed
of
the knitting machine. The butt 19 engages into cam profiles provided along or
around the needle bed in a well known manner and not disclosed. Furthermore
the slider 15 is provided with a pivot point 20 for enabling deviation, i.e.
an
oscillation motion of the slider around an axis extending orthogonal to the
slider
and positioned at pivot point 20. A further butt 21 is also provided on the
slider
15 for exercising a forced deviation of the slider, i.e. to control the
oscillation
thereof around the pivot point 20.
With every knitting needle 1 in the needle motion there are associated
two actuation sliders 15 as shown in the embodiment illustrated in figure 2,
or in
another type of realisation two actuation sliders 23 as shown in figure 4. In
some embodiments, it is possible to use for the same needle 1 a pair of
actuation sliders 15, 23, i.e. different from one another and made according
to
figures 3 and 4.
According to figure 4, in the alternative embodiment the slider 23 has a
bearing surface 16 for the hook 3, 4 of the knitting needle 1 anda projection
17
for hitching into the recess 13, 14 in the curved portion 9, 10 of the
knitting
needle 1. It is further provided with a rigid butt 19 for controlling 'the
axial
translation motions of the slider, and with a pivot point 20 for enabling
deviation,
i.e. an oscillation in the sliding groove of the needle bed, wherein the
slider is
slidingly housed.
The actuation slider 23 is further provided with a projection forming a
joint 29 for a hinged bearing of an auxiliary swinging slider 30, which is
shown in
working position in solid lines as well as in off-position in broken lines
(shown at
31). The auxiliary swinging slider 30 is provided with a seat 35 for the joint
29
such that the two sliders 23 and 30 can be stingingly connected to one
another.
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The swinging slider 30 is further provided with a butt 32 designed for
controlling
the oscillatory deviation motion and a butt 33 designed for controlling an
axial
translation motion. Due to the fact that the butt 33 is individually
selectable from
a working position to an off-position and vice versa, the swinging slider 30
is
predetermined not only for making basic structures, but also for different
cardigan and links-links patterns. The swinging slider 30 is actuable by means
of any patterning device that is known and therefore not shown in more detail.
The basic function of the needle motion, that is making the loops of the
knitted fabric, is shown on the series of figures 5a - 5e, and is common to
flat
knitting machines and double-cylinder knitting machines. Reference numbers
40 and 41 generically designate two needle beds, which can be either flat
needle beds or circular needle beds (needle cylinders of a double-cylinder
knitting machine). Figures 7a-7e show enlargements of the needle head in the
various positions shown in Figs. 5a-5e.
Figures 5a and 7a show an initial position of the needle motion. The
knitting needle 1 is hitched into one of the actuation sliders 15 and is
situated in
a weft position according to the figure 5a in the right knitting needle bed
40.
In the hook 3 of the knitting needle 1, there is situated for example a
jersey loop of the knitted fabric 36. The second, the opposite one, of the
pair of
actuation sliders 15 is situated in the left knitting needle bed 41, and
during the
whole stage of forming the new jersey loop is practically out of function. As
shown in figures 5b and 7b, the hitched actuation slider 15 with the knitting
needle 1 are moved in the direction towards the knitting needle bed 41 to such
a position that the loop of the knitted fabric 36 has moved over the curved
convex portion 9 of the knitting needle 1. By means of the thread guide that
is
known and not shown in figures 5b and 7b, the knitting thread 38 is laid into
the
space between the convex curved portion 9 and the tip 7 of the elastic buckle
5
of the knitting hook 3 of the knitting needle 1. In the next stage, shown in
figures
5c and 7c, a backward movement of the slider 15 and the knitting needle 1 is
realised in such a way that the knitting thread 38 gets under the elastic
buckle
5, but the loop of the knitted fabric 36 that is positioned on the stem of the
knitting needle 1 remains behind the curved portion 9. Subsequently, as shown
in figures 5d and 7d, a known presser 39 compresses the elastic buckle 5 in
such a way that the tip 7 of the elastic buckle 5 gets into the recesses or
slit 11
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provided the curved convex portion 9 of the knitting needle 1. This makes it
possible for the loop of the knitted fabric 36 that is positioned on the stem
2 of
the knitting needle 1, by a gradual motion in direction towards the weft
position
in the knitting needle bed 40, firstly to be put on the elastic buckle 5 and
subsequently to fall over the knitting hook 3 and to establish a new jersey
loop
37 of the knitting thread 38. The final position of the needle motion is shown
in
figures 5e and 7e. This position is practically identical with the initial
position
shown in figure 5a.
Another important feature of the needle motion is the possibility of
transferring the knitting needle 1 from one needle bed to another without
forming a new loop thereat. This process is shown in the series of figures 6a -
6e and in the enlarged details of figures 8a-8e, each showing an enlargement
of the needle area of figures 6a-6e respectively. An initial position of the
needle
motion is shown in figures 6a and 8a. This position of the needle motion is
the
same as the position shown in figures 5e and 7e. The initial step of the
process
of transferring the knitting needle is shown in figures 6b and 8b. The
actuation
slider 15 with the hitched knitting needle 1, that are situated in the right-
hand
knitting needle bed 40, gradually translate in the direction towards the left-
hand
knitting needle bed 41, whereas the knitted fabric 36, originally situated in
the
knitting hook 3, is moved onto the stem 2 of the knitting needle 1.
The actuation slider 15 that is situated in the left-hand knitting needle bed
41 is also in movement and gradually translates towards the knitting needle 1.
At the moment in which the bevel 18 of the actuation slider 15 touches the
hook
3 of the knitting needle 1, a gradual and spontaneous oscillatory deviation of
the
actuation slider 15 around the pivot point 20 on the needle bed 41 begins.
Subsequently, the knitting needle 1 hitches both actuation sliders 15. This
position is shown in figures 6c and 8c. After hitching the knitting needle 1
into
both actuation sliders 15 by virtue of a cam for the butt 21, which is known
and
therefore not shown, a forced oscillatory deviation of the slider 15 around
the
pivot point 20 on the needle bed 40 is carried out and the hook 3 with the
elastic
buckle 6 of the knitting needle 1 is released by the actuation slider 15 in
such a
manner as shown in figures 6d and 8d. The knitting needle 1 is hereby ready to
be moved into the knitting needle bed 41, whereas the knitted fabric 36
spontaneously moves into the hook 3 of the knitting needle 1, because the
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presser 39 is situated on the part of the knitting cam system on which this
movement is realised, and the elastic buckle 5 of the hook 3 of the knitting
needle 1 stays therefore still open. The final position of the needle motion
after
transfer of the knitting needle 1 is shown in figures 6e and 8e.
The process of forming a purl loop in the knitting needle bed 41 is
entirely symmetrical and analogical to the process shown in the series of
figures
5a - 5e, and the process of transferring the knitting needle from the knitting
needle bed 41 into the knitting needle bed 40 is entirely symmetrical and
analogical to the process shown in the series of figures 6a - 6e and therefore
will not be described in more detail. For the same reasons a use of the slider
23
in place of the slider 15, or a use of a combination of the two, will not be
described.
It is clear from the description of the above embodiments that for
transferring the knitting needle 1 between the needle bed 40 and the needle
bed 41 (being them either flat needle beds or else circular needle beds of a
double-cylinder knitting machine) without forming a new loop, the knitting
machine does not require any special mechanism for transmitting the loops,
which is the case of using the known double hook knitting needles. The
knitting
machine is therefore substantially simplified and, in addition, the duration
of the
production cycle is reduced, as after establishing the purl loop, the
subsequent
transferring of the knitting needle to a needle bed in which the jersey loops
are
being established, is made possible by means of a single movement of the
carriage of the knitting cam system. It is also clear that there exist no
mechanical restrictions as it is the case when knitting needle with actuation
pistons are used.
Industrial applicability
The knitting motion according to the invention is applicable to all
commonly used gauges of the knitting machines and is easily applicable to two-
needle bed and four-needle bed flat knitting machines, as well as to double-
cylinder small diameter, middle diameter and large diameter knitting machines,
whereas by variations of the type of the actuation slider 15 or 23, it is
applicable
both for more simple knitting machines designed for making only basic
reversible structures (wales) and for knitting machines designed for making a
knitted fabric with assorted reversible, links-links and cardigan patterns,
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especially for an automated production of conventional Rnitted underwear.
