Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates -to a device for manufacturing
knitted bags by means of a circular machine for tubular knitwear
that moves with continuous and unidirectional motion, as well as
a circular machine equipped with such a device.
A procedure is available for manufacturing a knitted bag
in a tubular knitwear by means of a circular knitting-machine
moving with continuous circular motion. Such procedure consists
in providing another continuous thread for the partial rows of
stitches, such thread being carried by a guide rotating around
the needles cylinder with non-uniform motion. At each turn, the
thread guide is arrested in correspondence with the first position
of stitch formation in order to feed the needles of an arc of
needles passing in front of it. Then, after surpassing said
needles until the second position of stitch formation is reached,
it continues to move at a constant speed but greater than the
speed of the needles cylinder. Finally, after a full turn, it
stops in correspondence with the initial position.
It is also know that a device is available to feed thread
from the additional thread guide employed for the forma~ion of
the second partial row of stitches according to the procedure
aforementioned. Such device allows the retention, under no
tension, of a sufficient length of thread for the formation
of the second partial row of stitches.
The main aim of the present invention is to propose
another and different device implementing the aforesaid procedure.
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This novel device is simple and effective so that the resulting
circular machine is highly reliable and versatile and of low cost.
According to the present invention, this result is
obtained by adopting the idea of employing a fall device that
makes use of a double contour cam, a countercam and a small pole.
The cam is external and concentric with the needles cylinder and
engages the needles employed for the formation of partial rows of
stitches. The device rotates with non-uniform motion in the same
direction as the cylinder in such a way that, at each and every
turn, it stops in a position where it leaves behind the additional
thread guide. At this position, one of the two contours of the
aforesaid cam triggers the first fall of said needles, which then
form the first partial row of stitches. The device then accel-
erates and passes the said needles remaining behind said additional
thread guide. Then, the small pole causes said needles to
rise from their held back level to the level where they are
dropped. The second cam contour causes a second Eall of said
needles, which then form a second partial row of stitches.
Finally, the cam slows down, reaching, after a full turn, the
initial position, where it stops.
The advantages obtained by virtue of the present
invention essentially consist of the possibility of having knitted
bags oE different form, size and position, manufactured with
continuous thread and unidirectional motion of the circular
machine. Among various knitwear obtained in this way we might
mention: socks with heel and pocket tip, briefs with front inner
liner, stockings and
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panty hose with liner. One can also have knitwear from yarns of
different colors, size and nature. Moreover, it is possible to
make use of circular machines, with one or two needles cylinders
and multiple feed, for manufacturing knitted tubes, and with two
or multiples of two additional feeds for manufacturing knitted
bags. Among other advantages of the invention one should mention
that it is now possible to have printed fabric, since one can
choose the needles for this purpose. Moreover, the manufacturing
operation is highly reliable and safe even at speeds much greater
than those of the present circular machines working with alterna-
tive motion. The high quality of the products is by far superior
than that of said alternative machines. Finally, the relative
construction simplicity of the device allows to equip a knitwear
circular machine with such device at competitive costs.
The invention is described in greater details as follows
with the help of the attached drawings, which represent only one
of the possible means of its implementation.
Figure 1 shows a cross section of the fall device in a
rest position according to the invention;
Figure 2 shows the fall device at the rest of Figure 1
during the formation of the first partial row of stitches;
Figure 3 shows the device in motion in the course of
forming the second partial row of stitches;
Figure 4 shows the sectors of a turn which are run at
different speeds by the fall device and by the additional thread
guide. At the center one finds the cam that controls the
different speeds.
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Figure 5 shows an axial vertical section of a knitwear
circular machine equipped with a device according to the inven-
tion;
Figure 6 shows a horizontal cross section of a detail of
the timing device of the additional thread guide associated with
the fall device according to the invention;
Figure 7 shows a horizontal cross section of a device
for controlling the rotation of the fall device and of the addi-
tional thread guide according to the invention;
Figure 8 shows a cross section of part of Figure 7;
Figure 9 shows a cross section of the remaining part of
the device of Figure 7.
Referring to the attached drawing and in its essential
elements the device for manufacturing knitted bags with continuous
motion of a circular machine for tubular knitwear according to the
invention includes: a fall device (200) concentric with and exter-
nal to the needles cylinder (1), with a cam (201) having two
active contours (211-212) designed to trigger two different falls
of the needles, a countercam (202) below cam (201), and a small
pole (203) coming before said cam (201) in the direction of rota-
tion. The function of the small pole is that of raising the
needles from a level where they are held back to a level where
they are dropped. Said fall device, which is connected to the
overhanging case (53) of the sinkers, rotates in one and the same
direction as cylinder (1), with intermittent motion, in such a way
that it stops at position (A) of Figure 4 corresponding to the
first area of stitch formation. Contour (211) of cam (201) then
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triggers the fall of needles (3) by a partial arc (for instance,
135) so as to form a first partial row of stitches. The fall
device then accelerates up to position (B) of Figure 4 where the
working speed is now greater (for instance, double) than that of
the needles cylinder. From this position it continues its motion
up to position (C) of Figure 4 with constant speed in order to
pass the needles by said partial arc and to allow the small pole
(203), in cooperation with contour (212) of cam (201), to raise
and then to let fall said needles, thus forming a second partial
row of stitches. Finally, the fall device slows down from posi-
tion (C) until it reaches position (A) of Figure 4 where it stops.
Moreover, said fall device can be radially displaced, with known
means, relative to the needles cylinder in order to change the
distance, thus engaging in this way the needles for different
partial arcs, depending on the type of knitted bag to be made (for
instance, heel or tip with closure of the lower end of a sock cr
stocking).
A circular machine for tubular knitwear equipped with
the aforementioned device includes: an additional thread guide
(98) radially positioned over cylinder (1) below platter (92).
Such thread guide is set into rotation by a hollow shaft ~97)
going through the vertical shaft of platter (92). The hollow of
said shaft (97) is used for the passage of the thread employed for
manufacturing the knitted bag and for the passage of air sucked
through the small opening (100) that assists said additional
thread guide.
The rotation of the additional thread guide (98) takes
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place in the same direc-tion as cylinder (1) and with intermittent
motion. At each and every turn, t~read guide (98) stops at posi-
tion (A'), as shown in Figure 4, behind cam (201) of said fall
device (200) in the course of the first thread feeding, then it
quickly accelerates up to position (B'), as shown in Figure 4, and
from there it continues up to position (C), as shown in Figure 4,
with constant speed in order to supply sufficient yarn for the
second feeding. Finally, from position (B) it begins to slow down
until it stops at the initial position (A').
Moreover, it is known that said additional thread guide
(98) can be radially displaced relative to cylinder (1). In this
way, the thread guide hook protrudes, in operation, towards the
external side of the head of the needles whereas, when it is not
in operation, it is near said small opening (100).
It is quite obvious that other similar thread guides
positioned one above the other, or side by side, can be associated
to said additional thread guide (98) so as to allow multiple yarn
feeing.
Several tongue needles (3) with double heel (130) dis-
tributed along the partial arc of needles required for making aknitted bag, whose upper heel, at every turn of cylinder (1), is
engaged by one (211) of the two contours of cam (201) for the
first fall, and by the small pole (203) for the following rise of
the needles from the position where they are held back to the
position where they are dropped, and by the other contour (212) of
cam (201) for the second fall.
Needles (3) belonging to different partial arcs, i.e.
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those required to make different knitted bags of the same knit-
wear, have upper heels of different length so that they can be
selected by the fall device (200), previously positioned along
corresponding distances from cylinder (1).
A wheelwork to obtain the unidirectional intermittent
rotation, as previously described, of the fall device (200) simul-
taneously with the rotation of cylinder (1), as well as of the
additional thread guide (98). Such wheelwork consists of an
epicyclic train with coincident axes, where the main wheels
(221-225) are along axis (220), the satellite wheels (222-224) are
along axis (223) and the gear carrier (226) has a wheel (227),
which is controlled by a spring (246), in contact with the contour
of cam (228) splined to the motor shaft (231). The movement
obtained from cylinder carrier (229) through wheel (230) splined
to shaft (231) is transmit-ted to the main wheel (221) by said
epicyclic train through coupling (232) and wheels (233-234-234'),
and from the main wheel (225) to transmission shaft (237) by means
of wheels (235-235'-236-236'). From the transmission shaft the
movement is transferred to the fall device (200) by means of wheel
(238). Moreover, the movement is transmitted from said shaft
(237) to shaft (97) of the additional thread guide (98) by means
of an epicyclic train with coincident axes, the main wheels
(239-241) being along axis (237), the satellite wheels (240-242)
being along axis (243), and by means of the train carrier (245),
of wheel (241') and of a geared belt (246).
Train carrier (226) of the first epicyclic train can
move in both directions relative to a middle position for which
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the transmission ratio of the wheelwork is determined by the
number of gear teeth (such ratio is equal to one), whereas the
ratio becomes positive or negative by displacing the train carrier
in one direction or the other. Hence, at any one time the posi-
tion of train carrier (226), which is controlled by the position
of the small wheel (227) over cam (228), determines the speed at
that time of the fall device (200) and of the additional thread
guide (98). Likewise, train carrier (245) of the second epicyclic
train, which has two possible working positions defined by the
contact of a small wheel with a cam carried by shaft (23) (for
simplicity, such small wheel is not shown in the figure), deter-
mines the instantaneous position of the additional thread guide
(in front or behind) relative to the fall device (200).
Instead of using an alternative forward and reverse
motion of the train carrier (226) one obtains a unidirectional
discontinuous motion by using a cam (228) with Archimedean spiral
contour that engages, one at a time, several small wheels (227) of
the train carrier (226).
In order to maintain the width of the knitted bags and
to conserve the number of additional double feedings, the rotation
of the needles cylinder will be carried out with variable rather
than constant speed, slowing down and stopping the cylinder during
the formation of the partial rows of stitches, when the fall
device (200) is still in motion.
