Textiles: spinning – twisting – and twining – Apparatus and processes – Alternate twist
Reexamination Certificate
1999-06-08
2001-03-06
Stryjewski, William (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Alternate twist
C057S294000, C057S350000, C057S351000, C057S908000
Reexamination Certificate
active
06195975
ABSTRACT:
TECHNICAL FIELD AND BACKGROUND OF THE INVENTION
This invention relates to a method for twisting individual strands of yarn and plying these individually twisted strands around each other, and the yarn made according to the method. More specifically, this twisting action is accomplished by false-twisting, where for a certain yarn length the yarn is twisted a number of turns in one direction and then for another sequential length, it is twisted in the opposite direction. The application also discloses yarns produced according to the method and on an apparatus of the type described.
The nature of false twisting is such that the total number of turns in one direction minus the total number of turns in the opposite direction over the total yarn-length is zero. The method of taking several twisted yarns and combining them by twisting them together to make a multi-stranded yarn has been known for thousands of years. However, plying previously-twisted yarns together is energy and time-consuming, since for every turn in the individual yarn and also for every turn in the plied multi-stranded yarn, the yarn packages must be turned around their axis.
The apparatus and method according to the invention is much more economical since only a relatively short piece of each yarn is twisted around its own axis. The secondary plying occurs automatically since, through the inserted torque, the twisted yarns in the single yarn twist around each other in the direction of the yarn-torque.
The false-twist process requires that care be taken to insure that the false-twisted multi-stranded yarn does not untwist at the place of twist-reversal. This is normally accomplished by attaching fibers of a single yarn to fibers of another, adjoining yarn. Various means of interlocking of these yarns at the twist reversal places have been used, for example, intermingling the fibers through abrasion, ultrasonic bonding, intermingling the fibers with an air-jet directing high-pressure air onto the traveling yarn, for example.
SUMMARY OF THE INVENTION
It is therefore an object of the invention to provide a multi-stranded, plied yarn by twisting a section of a given length of each individual strand around its own axis where the downstream sides of the yarns have twist in one direction and the upstream sides have the same amount of opposite twist. The twist direction is alternated periodically, whereby at twist reversal locations the fibers of the individual yarns are “tacked” by a fluid jet, such as an air-jet, the orifice of which moves substantially in unison direction and velocity with the traveling yarn, thus intermingling the fibers of the yarn effectively and over a relatively short distance.
It is another object of the invention to apply the twist to the individual yarns with stationary twisting elements as the yarns travel past the stationary twisting elements, whereby the direction of twist is periodically reversed.
It is yet another object of the invention to provide a rotating fluid-jet, wherein the timing of the activation of the jet coincides with the desired point of reversal of twist in the traveling yarn.
It is another object of the invention to control the insertion of twist by means of compressed air supplied by twist-inserting air-jets connected to solenoid valves, which are controlled through an electronic controller.
It is another object of the invention to provide a false-twist apparatus wherein compressed air to the twist-inserting jets through solenoid-valves which are controlled through an electronic controller with an electronic input and output where the input is received from the position of the traveling interlacing jet and the output controls the solenoid valves of the twist-inserting air-jets.
It is another object of the invention to provide a false-twist apparatus wherein the intermingling air-jet is placed off-center in the intermingling chamber, generating a partially rotating, intermingling air-stream in one direction where the direction of the rotation augments the self-wrapping of the yarn-strands.
It is another object of the invention to provide that two intermingling air-jets are employed which are placed off-center in opposite directions, each one to augment the self-wrapping of the yarn-strands in both direction.
It is another object of the invention to provide that the twist reversal of each yarn is controlled individually with the result that the twist reversal of one or more yarns is at a different location from the others along the plied yarn.
It is another object of the invention to provide that one or more yarns are not twisted for a given period of time or may never be twisted at all.
It is another object of the invention to provide that one or more yarns are twisted in opposite directions to another yarn in the plied yarn.
It is another object of the invention to provide that the amount of twist in one or more yarns are varied over the length of the plied yarn.
It is another object of the invention to control the rotational speed of a rotating air-jet in such a manner that the entangling jet moves approximately with the yarn process speed and is placed in such a manner that air is directed against the yarn at the point of twist-reversal of the yarn.
It is another object of the invention to control the rotational speed of a rotating air-jet and of the twisting jets during the operation in order to vary the distance between the places of twist reversal to prevent possible “moireé-effects” in the final product.
It is another object of the invention to control the rotational speed of a rotating air-jet and the timing of the twisting jets during the operation in order to vary the distance between two successive, adjacent points of twist reversal to prevent possible “moireé-effects” in the final product.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a process of producing an assembled yarn, comprising the steps of providing two or more yarns moving downstream from a supply to a take-up, inserting alternating-direction zones of twist into at least one of the yarns, said at least one yarn having an area of zero twist between said alternating direction zones of twist, combining the at least two yarns to form a single, integrated yarn strand, and intermittently exposing the yarn strand to an air blast to create a zone of intermingled yarns at spaced-apart points along the length of the yarn strand to prevent torsional movement of one yarn relative to the other yarn.
According to one preferred embodiment of the invention, the step of exposing the yarn strand to an air blast includes the step of intermingling the yarns at the areas of zero twist.
According to another preferred embodiment of the invention, the step of exposing the yarn to an air blast includes the steps of intermingling the yarns at the areas of zero twist, and intermingling the yarns at spaced-apart points along the length of the yarn strand other than at the areas of zero twist.
According to yet another preferred embodiment of the invention, the step of exposing the yarn to an air blast includes the step of intermingling the yarns at random points along the length of the yarn strand.
According to yet another preferred embodiment of the invention, the step of exposing the yarn to an air blast includes the step of intermingling the yarns at predetermined points along the length of the yarn strand.
According to yet another preferred embodiment of the invention, the step of exposing the yarn to an air blast includes the steps of intermingling the yarns at random points along the length of the yarn strand, and intermingling the yarns at predetermined points along the length of the yarn strand.
According to yet another preferred embodiment of the invention, the step of inserting alternating-direction zones of twist into at least one of the yarns comprises applying an air blast-induced torque to said yarn.
According to yet another preferred embodiment of the invention, the step of intermittently exposing the yarn strand to an air blast includes th
Hand Edward Lowe
Hand Gail F.
Jenkins Ralph Samuel
Niederer Kurt Willy
Rhyne Jeffrey Todd
Admas, Schwartz & Evans, P.A.
Belmont Textile Machinery Co. Inc.
Hand Gail F.
Stryjewski William
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