Textiles: knitting – Feeding – Strand tensions
Reexamination Certificate
2002-01-31
2003-04-22
Worrell, Danny (Department: 3765)
Textiles: knitting
Feeding
Strand tensions
C066S12500A
Reexamination Certificate
active
06550285
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a yarn feeding apparatus for feeding a knitting yarn, for knitting a fabric, to a weft knitting machine.
2. Description of the Related Art
Conventionally, a weft knitting machine
1
shown in
FIGS. 24 and 25
has a yarn feeding apparatus
6
provided in a side cover
5
in order to feed a knitting yarn
4
to a yarn feeding port
3
when knitting a fabric
2
. The yarn feeding apparatus
6
comprises a buffer rod
7
having a function of temporarily storing the knitting yarn
4
, and a function of adding tension to the knitting yarn
4
. The buffer rod
7
has a base end side
8
supported on the side cover
5
and can rock and displace a tip side
9
around the base end side
8
. The tip side
9
of the buffer rod
7
pulls the knitting yarn
4
by virtue of a spring and is stabilized with energizing force of the spring balanced with a tensile force based on tension of the knitting yarn
4
. A length measuring roller
10
serves to measure a length of the knitting yarn
4
to be fed from the yarn feeding apparatus
6
to the yarn feeding port
3
. As a result of the measurement of the length of the knitting yarn
4
, a stitch representing an amount of pull-in of a knitting needle pulled in through a carriage to knit the fabric
2
can be controlled such that an amount of consumption of the knitting yarn
4
is coincident with a predicted amount based on knitting data.
FIG. 24
shows a positional relationship of the yarn feeding port
3
in a state in which the carriage is moved toward the yarn feeding apparatus side of a needle bed in the weft knitting machine
1
, and is then started to be moved away from the yarn feeding apparatus
6
.
FIG. 25
shows a state in which the carriage is moved to an end apart from the yarn feeding apparatus
6
, and the yarn feeding port
3
is also moved over the fabric to an end on the side provided apart from the yarn feeding apparatus
6
. In the weft knitting machine
1
, an amount of demand for the knitting yarn
4
also fluctuates depending on the positional relationship of the yarn feeding port
3
with the fabric
2
. In the conventional yarn feeding apparatus
6
in which the knitting yarn
4
is stored and tension is provided within an inclination of the buffer rod
7
, the buffer rod
7
stores the knitting yarn
4
at a maximum with the yarn feeding port
3
reaching an end on the yarn feeding apparatus side of the fabric
2
as shown by a broken line of FIG.
24
. When the knitting operation for a next course of the fabric
2
is started, the yarn feeding port
3
is moved in such a direction as to go away from the yarn feeding apparatus
6
by virtue of the carriage. Since the knitting yarn
4
is pulled, the inclination of the buffer rod
7
is reduced as shown by a solid line. As shown in
FIG. 25
, when the yarn feeding port
3
approaches the end of the fabric
2
on such a side as to go away from the yarn feeding apparatus
6
, the amount of demand for the knitting yarn
4
is decreased and the inclination of the buffer rod
7
is increased again, as shown by a broken line, to pull in and store the knitting yarn
4
in a larger amount. The inclination of the buffer rod
7
corresponds to tension of the knitting yarn
4
. In such a structure in which the inclination of the buffer rod
7
provides a tension and stores the knitting yarn
4
, therefore, tension of the knitting yarn
4
fluctuates greatly during a middle of the knitting operation.
For example, Japanese Examined Patent Publication JP-B2 2541574 discloses conventional art in which tension is provided to a knitting yarn by using a member corresponding to the buffer rod
7
shown in
FIGS. 24 and 25
, and preliminary storage is carried out to cope with a sudden fluctuation, thereby suppressing a fluctuation in yarn tension while actively feeding a knitting yarn. Moreover, Japanese Unexamined Patent Publication JP-A 11-500500 (1999) aslo discloses conventional art in which rotation of a spinning wheel for feeding a knitting yarn is controlled prior to a sudden change in a demand for the yarn, thereby suppressing a fluctuation in yarn tension without using a member corresponding to the buffer rod
7
shown in
FIGS. 24 and 25
.
In the conventional yarn feeding apparatus
6
shown in
FIGS. 24 and 25
, the amount of demand for the knitting yarn
4
greatly fluctuates depending on a position of the yarn feeding port
3
, and the yarn tension also fluctuates depending on the demand for the yarn by an operation for knitting the fabric
2
in the weft knitting machine
1
. Also in conventional art, as described in the JP-B2 2541574, it is hard to cope with a sudden fluctuation in the amount of demand for yarn which results at the end of the fabric. In conventional art described in the JP-A 11-500500, it is expected that a countermeasure can be taken against a sudden fluctuation in the amount of demand for a knitting yarn. In this conventional art, however, it is necessary to wind the knitting yarn onto a spinning wheel. Therefore, a size of the spinning wheel is increased. In a weft knitting machine, a plurality of yarns are often used properly to knit a fabric so that a yarn feeding apparatus is to be provided for each yarn.
FIGS. 24 and 25
show that a precise amount of the knitting yarn
4
for the entire width of the fabric
2
is unknown even if the length of the knitting yarn
4
, which has already been fed to the length measuring roller
10
, is to be measured in order to feed the required knitting yarn
4
corresponding to knitting data of the fabric
2
. More specifically, in
FIG. 24
showing a data fetch starting position, it is possible to measure a precise length of the knitting yarn
4
only at a portion provided apart from the end of the fabric
2
by approximately several centimeters. In the case in which the buffer rod
7
is inclined from a state shown by a solid line to a state shown by a broken line, the amount of storage of the knitting yarn
4
, which is increased with the inclination of the buffer rod
7
, is also measured by virtue of the length measuring roller
10
so that the net amount of consumption of the knitting yarn
4
to be fed to the fabric
2
is unknown. Moreover, the amount of the knitting yarn
4
to be fed when the buffer rod
7
is returned from the state shown by the broken line to the state shown by the solid line cannot be directly measured by virtue of the length measuring roller
10
. Also in
FIG. 25
showing a data fetch ending position, the length of the knitting yarn
4
shown as a broken line is unknown. Also in the conventional art as described in JP-B2 2541574 and JP-A 11-500500, there is not disclosed a structure related to accurate measurement of the amount of demand for the knitting yarn.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a yarn feeding apparatus capable of accurately feeding a knitting yarn, required for knitting, to a weft knitting machine while suppressing a change in tension against a sudden change in demand.
The invention provides a yarn feeding apparatus for feeding a knitting yarn to a yarn feeding port, depending on demand for the knitting yarn in a weft knitting machine, for knitting a fabric while moving the yarn feeding port in a direction of a width of the fabric, together with a knitting operation to be carried out by an advancing and retreating operation of a knitting needle based on knitting data. The yarn feeding apparatus comprises:
a main roller provided in a feeding path for the knitting yarn and partially coming into contact with the knitting yarn on a rotatable outer peripheral surface of the main roller;
a servo motor for rotating a rotary shaft of the main roller;
a driven roller for interposing the knitting yarn, in contact with the outer peripheral surface of the main roller, between the driven roller and the outer peripheral surface;
a driven mechanism for transmitting a driving force from the servo motor to rotate the driven roller at an equal circumferential speed inte
Shima Seiki Manufacturing Limited
Wenderoth , Lind & Ponack, L.L.P.
Worrell Danny
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