Classifications

• • D—TEXTILES; PAPER
  • D03—WEAVING
  • D03C—SHEDDING MECHANISMS; PATTERN CARDS OR CHAINS; PUNCHING OF CARDS; DESIGNING PATTERNS
  • D03C3/00—Jacquards
  • D03C3/24—Features common to jacquards of different types
  • D03C3/44—Lingoes

Definitions

• the invention relates to a heddle tensioning device, in particular for weaving machines.
• Jacquard weaving machines generally have a so-called harness, to which heddle cords belong, with which warp threads are deflected upwards or downwards out of their warp thread level as required.
• the warp threads run approximately horizontally through the thread eye of an approximately vertically arranged strand.
• the strands are connected with a choir thread at their upper end loop.
• jacquard weights are attached to the lower end loop. The jacquard weights exert a constant downward force on the strands.
• the strand is held by the choir thread from above. By pulling or easing of the choir thread is raised or lowered, which is accomplished by a jacquard device. In this way, the warp threads can be raised or lowered individually or in groups to form a compartment for a weft insertion.
• the aim is to achieve very high numbers of shots.
• the jacquard weights are too sluggish for that.
• the jacquard weights have therefore been replaced in the past by steel springs, which exert a downward pull on the heald. With this, approx. 800 to 1,000 shots per minute can be achieved.
• the steel spring has to accelerate the strand downward, for example, which requires high forces at the number of shots mentioned.
• the steel spring must accelerate the strand, the warp thread and the choir or harness thread. The speed at which she can do this depends on her own mass. With fast weaving machines, the choir thread can weaken the strand faster than the spring can accelerate itself.
• the tension of the warp thread is increased.
• the warp thread thus supports the spring when the warp thread is transferred to the lower compartment.
• a higher warp thread tension represents an additional load on the warp thread, which increases the number of warp thread breaks and can therefore lead to a deterioration in the quality of the fabrics.
• the increase in the spring force is not only forbidden because of the possibly excessive stress on the choir threads or other parts, but also because an increase in the spring force also leads to an increase in the spring weight.
• the aim of the invention is to create a way to increase the working speed of weaving machines.
• the heald tensioning device has a working member which is connected to the heald to be tensioned and generates a force loading the heald in the tensioning direction by the pressure of a fluid.
• a gaseous fluid such as air
• the fluid (e.g. air) acting on the working element is almost massless, so that it can in principle generate very high accelerations.
• the working member can be made small and light by suitable choice of material and design.
• the pneumatically acting heald tensioning device thus fulfills all the requirements that the weaving machine needs to increase the number of weft, i.e. the working speed.
• the warp thread tension can be reduced. A reduction in the warp thread tension reduces its load, which means fewer thread breaks and can therefore lead to a better quality fabric.
• the working member is preferably a piston which for example, is mounted in a cylindrical straight tube so that it can be moved back and forth in a direction that corresponds to the tensioning direction of the strand.
• the force on the piston can in principle be generated by a fluid pressure difference between its two end faces. It can also be generated by an area difference, that is to say by differently sized end face areas to which a matching or different pressure is applied. Furthermore, it is both possible to generate the force difference occurring on the piston or other working member, which generates a resulting force for tensioning the strand, by means of overpressure and / or underpressure. Strand tensioning devices actuated by overpressure are considered advantageous because of the high achievable forces in a small installation space. In addition, dust or fiber residues are less likely to enter the system due to the prevailing excess pressure.
• the piston separates a working space in the tubular working cylinder, which is acted upon, for example, by a fluid under pressure, for example air. It is advantageous to connect the work space with a larger buffer volume, which is connected to the work space via a channel that has no appreciable flow resistance. As a result, the inflow of pressurized fluid from the buffer volume into the work area is not hindered, so that the pressure in the work area is almost constant even if the work area changes as a result of a piston movement in which the piston has the maximum expected or desired speed, enlarged.
• the free flow cross section of the connecting channel should not be narrower than the free cross section of the cylinder tube.
• the piston is preferably supported in the cylinder tube by an air cushion and sufficiently sealed. This is done by the piston with the inner wall of the cylinder derrohrs forms an air bearing.
• the air gap is preferably in the ⁇ m range.
• air channels can be provided in the piston, which open out on its lateral surface and are fed, for example, from the end face. The air loss occurring through the gap between the piston and the cylinder wall is negligible.
• the piston is connected to a traction device, with which the stranded wire is in turn connected.
• the traction means can be, for example, a plastic wire (polyamide monofilament, Perlon monofilament) or a round steel wire.
• the piston and the cylinder tube can be made of plastic.
• the traction means is guided through a wall that closes the cylinder tube.
• a plastic bushing can be arranged in the opening in question, which guides the traction means and thereby seals the working space.
• the traction means and the bushing can also be designed so that they form an air bearing. Overall, this results in an almost frictionless and wear-free arrangement with which quick strand movements can be generated and the warp thread load can be reduced.
• the heddle tensioning device according to the invention is thus suitable for increasing the number of weft of a weaving machine.
• Said heald tensioning device can also form the basis for a heald tensioning arrangement in which many similar heald tensioning devices are arranged next to one another and in each case individually pretension a traction means operated with a heald.
• the heddle tensioning devices of the heddle tensioning arrangement can be controllable individually or in groups.
• the strand tensioning devices, which are controlled jointly, can have a common buffer volume. The buffer volume should preferably exceed at least ten times the stroke volume of all connected strand tensioning devices. Further details of advantageous embodiments of the invention are the subject of the drawing, the description or the subclaims.
• FIG. 1 is a schematic illustration of a heddle tensioning arrangement
• FIG. 2 shows the strand tensioning arrangement according to FIG. 1 in a front view
• FIG. 3 shows the heddle tensioning arrangement according to FIG. 2 in a sectional illustration, cut along the line B-B in FIG. 2,
• Figures 4 and 5 embodiments of individual strand tensioning devices each in a longitudinal section.
• FIG. 1 illustrates a strand tensioning arrangement 1 which serves to exert downward tensile forces on a group of strands (not illustrated further).
• the strands are connected to the traction means 2 running upward from the lit tensioning arrangement 1.
• the heddle tensioning arrangement 1 is actuated pneumatically, ie the tensile force acting on the connecting means 2 is generated pneumatically.
• the heddle tensioning arrangement 1 is preferably connected via a control device 3 to a compressed air source, which is not further illustrated.
• To the control device 3 includes control valves 4 and a controller 5 for controlling 'the control valves.
• a strand tensioning arrangement 1 is illustrated in FIGS. 2 and 3, in which all connecting means 2 are subjected to the same tensile force. Therefore, only a single compressed air connection 6 is provided.
• the heddle tensioning arrangement 1 has a heddle tensioning device 7 for each connecting means 2.
• the strand tensioning devices 7 are essentially identical to one another. They each consist of at least one cylinder tube 8 and a piston 9 slidably mounted therein as a working member.
• the cylinder tubes 8, which are arranged parallel to one another, are each held at their upper and at their lower ends in a holding plate 11 or 12, which have corresponding bores in which the cylinder tubes 8 sit in a fluid-tight manner.
• the upper holding plate 11 is overlapped by an end plate 14 which, with the holding plate 11, defines a flat space 15 which is closed off from the outside and into which the upper open ends of the cylinder tubes 8 and the compressed air connection 6 open. Via an opening 16 in the holding plate 11, the space 15 is connected to a buffer volume 17 which is delimited by a wall arrangement 18. This is closed at the bottom by the holding plate 12 and connects tightly to the holding plate 11 at the top.
• the end plate 14 has 8 holes in alignment with each cylinder tube, in which. Guide bushings 19 are seated.
• the piston 9 forms an air bearing with the respective cylinder tube 8.
• the cylinder tubes 8 are open at both their upper and lower ends. They protrude through the lower holding plate 12 and are preferably covered here by a cover plate 22 which defines a space 23 with the holding plate 12. This is vented to the outside.
• a connection 25 provided with a corresponding filter 24 can serve this purpose. The filter prevents dust from entering the space 23 and the cylinder tubes 8 when the pistons 9 reciprocate.
• the strand tensioning arrangement 1 described so far operates as follows:
• strands are connected at their lower ends, each hanging from a harness cord at their respective upper ends.
• Each strand has a strand eye through which a warp thread is passed.
• the space 15 and the buffer space 17 are supplied with compressed air via the connection 6.
• This has a pressure of 6, for example cash on.
• the pressure acts on the upper end faces of the pistons 9, while the lower end faces are acted upon by the substantially lower ambient pressure. Accordingly, a downward force is generated on each connecting means 2. If all or individual harness cords suddenly drop because the corresponding strand and the associated warp thread are to be moved downward to form the shed, the piston 9 in question pulls the strand down over the connecting means 2.
• the entire force exerted by the compressed air on the piston 9 can act to accelerate the strand, the harness thread and the warp thread. This results in a very rapid downward adjustment movement, whereby compressed air can flow from the buffer volume 17 into the relevant cylinder tube 8.
• the space 15 serving as a channel Due to its large cross-section, which is preferably significantly larger than the sum of the cross-sections of all cylinder tubes, the space 15 serving as a channel has a very low flow resistance, so that there is no throttling effect which inhibits the piston movement of the pistons 9. The same applies to the space 23, which hardly impedes the air separated from the pistons 9 from the cylinder tubes 8.
• the heddle tensioning arrangement 1 thus enables a particularly rapid adjusting movement of the heddles with relatively low resting forces. It is not very susceptible to vibrations, such as those that occur with steel springs when they are used to tension strands.
• the heald tension arrangement 1 thus permits increased numbers of weft or turns of the weaving machine.
• FIG. 4 illustrates an embodiment of a heddle tensioning device 7, which can be used as a module for building a Strand tensioning arrangement is suitable, which consists of a plurality of such strand tensioning devices 7.
• the heddle tensioning device 7 has a cylinder body 26 which is provided with a central bore 27. Buffer holes 28, 29 are arranged around them. Both at. The top and bottom of the cylinder body 26 are closed by caps 31, 32, each of which has a recess 33, 34 on the side facing the cylinder body 26, via which the buffer bores 28, 29 communicate with the cylinder bore 27.
• the buffer volumes 28, 29 of adjacent strand tensioning devices 7 should be combined in pairs or groups and connect several central bores 27 to one another. The distance between the central bores 7 can thereby be minimized.
• the piston 9 is connected to the connecting means 2, which is guided through the guide bush 19 seated in the cap 31.
• the piston 9 is provided with a tubular extension 35, the diameter of which is larger than the diameter of the connecting means 2 and the length of which exceeds the maximum stroke of the piston 9.
• the extension 35 thus projects in each working position of the piston 9 through an opening 36 provided in the cap 32, forming an air bearing with the wall thereof.
• FIG. 5 A modified embodiment is illustrated in FIG. 5. At its lower end, this has a cylinder tube 8, which is combined with an end piece 37 and in which the piston 9 is displaceably mounted.
• the cylinder tube 8 is surrounded by a jacket tube 38, which is arranged concentrically with the cylinder tube 8 and forms an annular buffer space 39 therewith. This is closed at its upper end by a cover 41 through which the connecting means 2 pass.
• a guide bushing 19 is seated in the cover 41.
• the compressed air connection 6 serves to supply the buffer space 39 and thus the working space with compressed air.
• a so-called heald spring is required to generate a heald movement, which generates a tension force acting on the heald.
• an air cylinder is used in which a piston is mounted with low friction. A monofilament connects the piston to the strand and thus forms a piston rod that is under tension. Due to the area or pressure difference between the two end faces of the piston, a tension force arises which, due to the low weight of the piston and the connecting means 2, allows very fast adjustment movements and thus a very fast shedding and a high number of revolutions of the weaving machine.

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

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• 2003
  • 2003-02-07 DE DE2003105016 patent/DE10305016B4/de not_active Expired - Fee Related
• 2004
  • 2004-01-16 EP EP04737241A patent/EP1590516B1/de not_active Expired - Lifetime
  • 2004-01-16 DE DE502004009748T patent/DE502004009748D1/de not_active Expired - Lifetime
  • 2004-01-16 WO PCT/EP2004/000276 patent/WO2004072341A1/de active Application Filing
  • 2004-01-16 CN CN200480003791.8A patent/CN1748051B/zh not_active Expired - Fee Related
  • 2004-02-06 TW TW93102703A patent/TWI248484B/zh not_active IP Right Cessation

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