Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03D—WOVEN FABRICS; METHODS OF WEAVING; LOOMS
  • D03D47/00—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms
  • D03D47/28—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms wherein the weft itself is projected into the shed
  • D03D47/30—Looms in which bulk supply of weft does not pass through shed, e.g. shuttleless looms, gripper shuttle looms, dummy shuttle looms wherein the weft itself is projected into the shed by gas jet
  • D03D47/3006—Construction of the nozzles
  • D03D47/3013—Main nozzles

Definitions

• the invention relates to a nozzle for thread transport in pneumatic textile machines, in particular for the pneumatic insertion of weft threads into the shed of a weaving machine.
• the weft thread is fed into the shed formed from warp threads by means of a carrier medium stream, i.e. H. Air, registered.
• a carrier medium stream i.e. H. Air
• the airflow is generated by a nozzle either on the machine frame or directly on the drawer.
• the nozzle usually consists of a nozzle jacket with a supply opening for the compressed air and a nozzle core with a continuous axial channel for guiding the weft thread to be inserted.
• One of the essential requirements for the nozzles of pneumatic weaving machines is the generation of the greatest possible tensile force on the weft thread with a relatively low compressed air consumption and the best possible centering of the weft thread in the outflow chamber without vibrations, in particular of its front end.
• the requirement is met by various redirectors, which are intended to orientate the pressure medium flow as best as possible, which is fed into a mixing chamber of the nozzle jacket, in parallel to the axis of the weft thread to be inserted.
• These detours are usually formed by variously shaped ribs or openings that orient the print medium.
• the disadvantage of such diversioners lies above all in the considerable production outlay due to the necessary accuracy of the processing and often also in an inadequate working method.
• the object of the invention is to substantially reduce these disadvantages and to improve the mode of operation and the service life of a structurally simplified weft insertion nozzle.
• the outflow chamber contains a first straight section and a second straight section which are connected to one another by at least one curved section.
• tubular outflow chamber has at least two ventilation openings with an adjustable opening width in front of the outflow end.
• the advantage of this solution is, in addition to the structural simplicity, in the setting of a relatively high pulling effect on the weft thread to be introduced with a relatively small amount of carrier medium.
• the air streams drawn in laterally into the outflow chamber result in an additional injection effect with a stretching of the weft thread and a damping of its fluttering movements. This effect is intensified if the radial bores are arranged in the region of a constriction of the discharge chamber.
• the nozzle shown in the drawing is attached to a fixed component of a pneumatic weaving machine and has a hollow cylindrical nozzle body 1, in the axially continuous interior 4 of which a core 2 is installed.
• This core 2 has a cylindrical portion 2a, the flat end face is flush with the end face of the nozzle body 1 and the z. B. is fixed by gluing, pressing or a thread in the inlet portion of the nozzle body 1.
• a central cone 2b, which extends inside the nozzle body 1, is formed on this cylindrical section 2a of the core 2.
• a central through hole runs in the axis of the core 2 Passing through a weft thread 3 shown in broken lines.
• one end of a tube 6 is fastened, which forms an elongated outflow chamber for a pressurized fluid, in particular for a pressurized air stream.
• a radial connecting piece 5 is arranged approximately in the middle of the nozzle body 1, via which the pressure fluid is introduced into a mixing chamber 4 in the interior of the nozzle body 1.
• This mixing chamber 4 is delimited on the inside by the elongated central cone 2b of the core 2, on the outside by the inner wall of the nozzle body 1 and on the left side by the cylindrical core section 2a.
• the narrow end of the cone 2b protrudes slightly into the coaxial pipe section 6a, so that there is a relatively narrow annular gap between the cone end and the pipe section through which the pressure fluid flows from the mixing chamber 4 into the pipe 6, possibly at an increased speed.
• the one-piece tube 6 consists of a first straight section 6a, which is coaxial with the nozzle body 1, of an arc piece 6b (quarter curve) and of a further straight section 6c which is expediently longer than the first straight section 6a.
• the pressure medium is fed through the opening 5 into the mixing chamber 4.
• the pressure medium In the area of the outflow from the mixing chamber 4 around the mouth of the nozzle core 2, the pressure medium is accelerated and produces an ejection effect in the bore 2c of the nozzle core 2.
• the weft thread 3 is sucked in by this ejection effect.
• a turbulent flow of the pressure medium develops, which acts on the weft thread 3 Tractive force increased.
• the turbulence of the pressure medium is reduced, the flow profile of which is further evened out in the second straight section 6c of the outflow chamber.
• the weft thread 3 in the bow piece 6b is pressed against the inner radius of the bow 6b by the tensile force acting on it in the second straight section 6c, thereby preventing its vibrations from being transmitted from the first straight section 6a to the second straight section 6c of the outflow chamber.
• the weft thread 3 is centered in the axis of the outflow chamber.
• the outflow chamber is formed by a straight tube 6 which has a plurality of radial bores 7, 8 in section 10 at a suitable distance from its outflow end.
• a sliding bushing 9 is arranged on the tube 6, which has an inner flange at its ends, each with a sealing ring.
• both solutions can be combined with one another, which results in a weft insertion nozzle whose discharge chamber contains a first straight section, an arc section and a second straight section, at least in one of these sections Ventilation openings of adjustable opening width are provided.
• the inner cross section of the tubular outflow chamber can change at certain points in order to influence the flow conditions and to improve the guidance of the thread.
• a greater additional ejector effect can be achieved if the ventilation openings are made in the form of circumferential slots distributed over the circumference of the chamber in a zone of gradually reduced internal cross section in the outflow chamber wall.
• This reduced internal cross section can, for. B. generated by a simple annular indentation of the chamber wall.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Looms (AREA)

Applications Claiming Priority (4)

Publications (1)

Family

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Family Applications (1)

Country Status (1)

Cited By (1)

Citations (4)

• 1988
  • 1988-09-22 EP EP88115589A patent/EP0308930A1/fr not_active Withdrawn

Patent Citations (4)

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