Classifications

• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B15/00—Details of, or auxiliary devices incorporated in, weft knitting machines, restricted to machines of this kind
  • D04B15/66—Devices for determining or controlling patterns ; Programme-control arrangements
  • D04B15/68—Devices for determining or controlling patterns ; Programme-control arrangements characterised by the knitting instruments used
  • D04B15/78—Electrical devices
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B1/00—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes
  • D04B1/10—Patterned fabrics or articles
  • D04B1/12—Patterned fabrics or articles characterised by thread material
  • D04B1/126—Patterned fabrics or articles characterised by thread material with colour pattern, e.g. intarsia fabrics
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B1/00—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes
  • D04B1/22—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes specially adapted for knitting goods of particular configuration
  • D04B1/24—Weft knitting processes for the production of fabrics or articles not dependent on the use of particular machines; Fabrics or articles defined by such processes specially adapted for knitting goods of particular configuration wearing apparel
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B15/00—Details of, or auxiliary devices incorporated in, weft knitting machines, restricted to machines of this kind
  • D04B15/32—Cam systems or assemblies for operating knitting instruments
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B15/00—Details of, or auxiliary devices incorporated in, weft knitting machines, restricted to machines of this kind
  • D04B15/66—Devices for determining or controlling patterns ; Programme-control arrangements
  • D04B15/68—Devices for determining or controlling patterns ; Programme-control arrangements characterised by the knitting instruments used
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B15/00—Details of, or auxiliary devices incorporated in, weft knitting machines, restricted to machines of this kind
  • D04B15/94—Driving-gear not otherwise provided for
  • D04B15/99—Driving-gear not otherwise provided for electrically controlled
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B9/00—Circular knitting machines with independently-movable needles
  • D04B9/26—Circular knitting machines with independently-movable needles for producing patterned fabrics
  • D04B9/28—Circular knitting machines with independently-movable needles for producing patterned fabrics with colour patterns

Definitions

• the object of the present invention is an underneedle selection device of a knitting machine.
• the yarns are processed by a plurality of needles arranged in relative grooves of a cylinder (in the case of a circular machine) or a needle bed (in the case of a rectilinear machine).
• the needles involved in the work are mechanically selected by corresponding undemeedles, also called Jacks, provided with a tooth, also called heel.
• each underneedle is selected by a selection device comprising a plurality of selection tips overlapped in height that act on respective heels of undemeedles by actuating means controlled, for example, by a calculator wherein the design or the work to make are stored.
• the main one is the actuating speed, which is determined by the time needed by the selection tip to enter and select the underneedle corresponding to the desired colour or threading stitch and by the time needed to come out when the undemeedle selection is not required.
• the undemeedle In the selection by rise, the undemeedle is physically raised during the movement of the cylinder or of the needle bed, in one vertical groove whereof it is inserted and guided, by a special selection tip, also called selection lever, especially shaped with an inclined plane whereon the undemeedle heel rises, so that the corresponding needle may hook the thread moving upwards.
• a special selection tip also called selection lever, especially shaped with an inclined plane whereon the undemeedle heel rises, so that the corresponding needle may hook the thread moving upwards.
• the undemeedle is squeezed into the groove wherein it is seated by a special lever or selection tip.
• the needles that are not squeezed, thus not selected, are made to move upwards by a special fixed cam so that they can hook the thread.
• a first type of selection devices is that of mechanical devices. They are comprised of rolls or drums that rotate in a synchronous manner with the machine cylinder and wherein pins are placed according to the pattern or the work to be obtained.
• a second type is that of electromagnetic devices. They are used both in working cycles by squeeze, wherein an electromagnet rises and lowers a respective selection tip that will interfere with the undemeedle heel, pushing it into the groove, and in the working cycles by rise, wherein the electromagnet moves forward a very inclined tip equal by the rising stroke the undemeedle must run, generally 5-6 mm.
• the tip is heavier and therefore the movement cycle is slower and requires a more powerful electromagnet.
• the electromagnet excitation time ranges from 10 to 30 ms, exerting a considerable strength required for the mechanical movement.
• a third type is that of piezoelectric selection devices. They are only used in working cycles by squeeze, rising or lowering the selection tip that will interfere with the undemeedle heel. These actuators are provided with piezoelectric sheets, for example ceramic sheets, which according to the electrical polarisation they are subject to, move upwards or downwards, mechanically moving the selection tip, which is pivoted on a pin that withstands the mechanical impact with the underneedle.
• the selection tip of these devices is lighter so as to be moved by the sheet of the piezoelectric ceramic.
• the excitation time of the piezoelectric ceramic is up to 5 times shorter than the electromagnet solution. For example, an ON/OFF cycle lasts about 6 ms.
• the actuation speed of the piezoelectric ceramic allows using a smaller number of tips, increasing the working speed of the machines and reducing the mechanical overall height dimensions of the cylinder, reducing the rotating masses of the machine.
• a further type of selection devices is that of mono-magnetic devices. They are actuators that make the selection of the underneedle magnetically attracting the heel thereof. All the heels of the undemeedles are on the same level and therefore the scaled elimination of the heels is not required.
• the electromagnetic actuators are intrinsically slow and therefore require a large number of selection tips to make the selection of the undemeedles at the same rotation speed of the needle holder cylinder.
• the piloting reels absorb high currents with consequent consumption and generated heat.
• the electronic piloting cards are expensive since they require powerful piloting terminals according to the absorption. Moreover, they must be suitable for generating overvoltage pulses for accelerating and overcoming the initial mechanical inertia of the magnet anchor.
• the selection unit is subject to a higher structural degradation compared to the other solutions, due to the strong mechanical stresses and to the deterioration of the magnetic coils for the strong heat.
• the stroke by deformation on electrical stimulation of the piezoelectric sheets is limited by the structure of the ceramic itself and is directly proportional to the piloting voltage.
• the selection tips of the current piezoelectric devices can run strokes of +1mm with positive excitation and -1 mm with negative excitation, compared to a central 0 position, without voltage.
• the current direct current piloting voltage uses a range of +/- 50-100 V, therefore the piezoelectric ceramic uses a voltage of 100-200 V at the terminals thereof.
• Lower voltages limit the extension of the stroke of the selection tip and also increase the time required for switching, which can shift from 3ms to 5ms. Higher voltages require suitable cables and connectors for insulation and safety.
• the knitting machines must have very precise and expensive mechanical processing. In fact, they must have the maximum mechanical efficiency so that all the magnetic field generated is concentrated as much as possible on the heel of the undemeedle to be selected.
• the machine speed is mainly limited by the magnetic hysteresis cycle of the undemeedle heel.
• the undemeedles can partly remain polarised, becoming magnetised and thus more difficult to be selected. Therefore, the material used for the undemeedles must exhibit particular features of magnetic permeability that make it more expensive besides being more wearable than the normal undemeedles, which are of suitably treated steel to withstand wear and mechanical stresses.
• the object of the present invention is to propose an undemeedle selection device which should allow obviating at least partly the disadvantages mentioned above with reference to the known selection devices.
• FIG. 1 schematically shows a cutaway view of the selection device according to the invention in a first embodiment and in interaction step with the undemeedles of a cylinder;
• - figures 2, 2a and 2b show side views of a single selection tip of the device, in the two working and non operating positions;
• FIG. 2c-2e schematically show two selection tips arranged in a sequence, in the situations of disabling of both, enabling of first only, enabling of both, respectively;
• - figure 3 shows a plan view of the selection tip;
• FIG. 4 schematically show plan views of a portion of a device according to the invention, in a second embodiment, and with a selection tip in the two working and non operating positions;
• - figures 5, 5a and 5b show as many views of a stop member associated to the device of figure 4;
• FIG. 6 and 6a schematically show a plan and longitudinal section view of an element of the selection device in an interaction step with an underneedle
• FIG. 7 and 7a schematically show a plan and longitudinal section view of an element of a selection device in a further embodiment, in an interaction step with an underneedle and in the non operating condition
• - figures 8 and 8a schematically show a plan and longitudinal section view of an element of the selection device in an interaction step with an underneedle and in the working condition; and [0050] - figures 9 and 9a schematically show a plan and longitudinal section view of an element of a selection device in a further embodiment, in two different positions of the selection tip.
• reference numeral 1 schematically denotes a cylinder of a circular knitting machine.
• Cylinder 1 carries along the circumference, seated in special grooves 1' parallel to the cylinder directrices, a plurality of needles, not shown, under each whereof there is placed an underneedle 2.
• Each underneedle is provided with a tooth, or heel 4, which protrudes from the cylinder groove to be engaged by an underneedle selection device, globally indicated with reference numeral 10, which is the object of the present invention.
• the selection device 10 comprises a plurality of selection tips 20; 40; 60; 80, each having a contact profile 21 ; 41 ; 61 ; 81 suitable for interacting with a corresponding heel 4 of an underneedle 2 for making the selection thereof.
• the selection tips are vertically aligned, that is, parallel to the axis of cylinder 1, so as to form a group of tips shaped as "comb".
• the underneedles therefore exhibit the respective heels 4 at different heights, each heel being positioned at a height equal to the height of a corresponding selection tip of the group of tips.
• Each selection tip 20; 40; 60; 80 is associated to at least one respective abutment means 22; 42; 62; 82 acting as mechanical support stop for the respective tip, as will be better explained hereinafter.
• the selection device 10 further comprises actuating means 30 suitable for moving at least one between said selection tip and said abutment means between a non working position, wherein at least one between said selection tip and said abutment means is in a non interference position with the underneedle heel during the cylinder rotation, and a working position wherein the selection tip is subject to be pressed by the heel resting on the abutment means, the underneedle being forced to follow the contact profile of the selection tip following such interference between tip and abutment means.
• the actuating means are used not to perform the total movement of the selection tips, required to cause the movement of the underneedle, but only for "enabling" to perform the selection itself, whereas the mechanical movement work of the underneedle is performed directly by the underneedle itself in contact with the selection tip.
• the selection tip and/or the respective abutment means are moved only as much as required to place them in the range of action of the heel, so that they interfere therewith upon the passage of the heel at the selection device.
• Such interference of the selection tip or of the abutment means with the heel has the effect of sending the tip resting on the abutment means, after which the rotation of the cylinder forces the underneedle to follow the profile of the selection tip.
• the actuating means are therefore forced to impose a minimal movement to the selection tip or to the abutment means, in the range of few tenths millimetre, for example equal to 0.1 - 0.3 mm, according to the type of application. An actuating time of about 1 ms is therefore obtained. [0061] By virtue of the little movements, this innovative solution allows using the piezoelectric ceramic not only for actuators that work by squeeze of the underneedle, but also to make new actuators that work by rise, as will be described hereinafter.
• the condition of interference with the underneedle heel is associated to a working position of the selection tip or of the abutment means, since usually this condition implies a selection of a needle and therefore a hooking of a yarn.
• the mechanics of the knitting machine may also be made to obtain a reverse effect, that is, so that a selection of an underneedle made by an interference of its heel with a selection tip prevents a selection of the respective needle.
• the positioning of the selection tip or of the abutment means beyond or in interference with the normal stroke of the underneedle heel is obtained with a movement of the tip and/or of the abutment means in a plane orthogonal to the plane wherein the underneedle heel rotates.
• the selection tip 20 has a profile 21 of contact with the guiding heel comprising an inclined plane suitable for causing a height shifting of underneedle 2.
• the selection tip 20 is movable between a raised non- operating position, wherein heel 4 of underneedle 2 moves below said tip without interfering therewith, and a lowered operating position, wherein heel 4 intercepts the contact profile 21 of tip 20, pushes it against the abutment means 22 thereof and continues its rise along profile 21.
• a further inclined plane 24 of a fixed cam 25 extends from the top end of the inclined plane 21 of the selection tip 20, suitable for rising the underneedle at a desired height.
• the selection tip 20 oscillates by the actuating means 30 about an axis of rotation X that extends at the opposite end relative to the inclined plane profile 21.
• tip 20 exhibits a first central hole 26 for coupling to an end bar 31 of the actuating means 30, and a second side hole 27 wherein pin 27' is inserted for the oscillation of tip 20 about axis X.
• arrow F1 indicates the direction of rotation of cylinder 1 relative to the selection device 10
• arrow F2 indicates the direction of the stroke performed by heel 4 while it rises on the inclined plane 21 of tip 20 and on the optional second inclined plane 24
• arrows F3 indicate the directions wherein the selection tip 20 oscillates.
• the physical movement of the selection tip 20 is carried out by heel 4 of underneedle 2 which during the rotation of cylinder 1 , encounters the selection tip 20 on its path, lowered as much as needed to force it to rise on the inclined plane 21. In this way, tip 20 receives a sufficient force to make it rest on its abutment means 22, which becomes the mechanical anchoring point.
• underneedle 2 continues to go up following the inclination of the inclined plane 21 , at the end whereof, if required, it will find a further fixed cam 25, which will further lift it up to the height useful for making the selection.
• the selection tip 40; 60; 80 has a contact profile 41 ; 61 ; 81 with heel or tooth 4 suitable for causing an oscillation of undemeedle 2 inwards of cylinder 1.
• the selection tip 40; 60; 80 is capable of being moved in a plane orthogonal to the axis of the cylinder, that is, horizontally, between a retracted non working position, wherein it is away from the cylinder, and an advanced working position, wherein the contact profile is substantially tangent to the cylinder.
• the abutment means 42; 62; 82 is movable by the actuating means 30 between an inactive position wherein it does not interfere with the respective selection tip 40; 60; 80 and an active position wherein it interferes with the selection tip forcing the latter to remain in advanced working position.
• the selection device further comprises positioning means 90 that influence the selection tip 40; 60 to remain normally in advanced operating position.
• said positioning means 90 exert on the same selection tip a weaker force than that exertable on the tip itself by heel 4 of underneedle 2 during the cylinder rotation. In this way, in fact, when the abutment means 42; 62 is in inactive position, the tip is moved in retracted position by the underneedle itself, which overcomes the strength exerted by the positioning means.
• the selection tip 40; 60; 80 is pivoted at an end thereof, so as to be oscillating about a vertical axis Y, that is, parallel to the axis of cylinder 1.
• the selection tip 40; 60; 80 is completely disconnected from the actuating member 30 which on the contrary causes the movement of the abutment means 42; 62; 82; for example, the tip is simply supported by a fixed structure 84 of the selection device.
• the selection tip is guided to shift radially relative to the cylinder.
• the abutment means 42 is shaped as a pin or pivot with substantially vertical axis.
• said pin or pivot 42 exhibits a cross hole 43 for being engaged on an end bar 31 of the actuating means 30.
• the abutment means 42 comprises a surface of contact with the tip having a top portion 42' and a bottom portion 42" tapered in opposite direction.
• Tip 40 in turn has a contact surface 40', facing the side opposite profile 41 , that is, facing the back, preferably configured complementary to the contact surface of the abutment means.
• the latter is respectively further pushed downwards or pushed upwards by the tip itself, which therefore facilitates the movement of the actuating means 30.
• the movement that the actuating means 30 must impart to the abutment means 42 to make it interfere or not with the selection tip 40 is a minimal movement, only needed to position the abutment means 42 just above or just below the horizontal plane whereon the selection tip 40 moves.
• the abutment means 62 is shaped as a pin or pivot with substantially horizontal axis, that is, which extends in a radial direction relative to the cylinder.
• Such pin or pivot 62 has a head 62' suitable for interfering with a corresponding abutment head 64 obtained in the selection tip 60 and facing the back, towards pin 62.
• Tip 60 therefore differs from tip 40 described above only in that it has the abutment head 64 in place of the back contact surface 40'.
• the device in this last embodiment is even more compact in height, thanks to the horizontal extension of the pin or pivot 62.
• Figures 7 and 7a schematically show pin 62 kept into lowered position by the actuating means 30, so as to not interfere with head 64 of the selection tip 60.
• Arrow F3 in figure 8a indicates the oscillation imparted by the actuating means 30 on pin 62.
• pin 62 is made to oscillate (arrow F3) in substantially horizontal position so as to intercept head 64 of tip 60 and prevent a movement thereof in retracted position by heel 4.
• heel 4 is squeezed by tip 60 inwards of the cylinder.
• the positioning means 90 of the selection tip 40; 60 comprise elastic means.
• said means comprise magnets 91 placed on the tip and on the support structure so as to generate a magnetic field, for example of repulsion, which tends to move tip 40; 60 away from the support it is engaged on.
• the selection tip 80 takes on the shape of a toothed wheel free to rotate about an axis Y parallel to the cylinder axis.
• Teeth 80' of the toothed wheel 80 constitute the actual selection tips that interact on the one side (profile 81) with heels 4 and on the opposite side with the abutment means 82.
• the latter can take the shape of the pin with vertical axis 42 or of the pin or horizontal pivot 62 described above.
• the toothed wheel 80 is made to rotate by the underneedle heels during their passage, at the same speed of rotation of the machine.
• the activation of the actuating means causes the enabling of the abutment means 82, which interferes with a tooth 80' of the wheel, preventing it from rotating.
• the heel is forced to follow the profile of the adjacent tooth of the wheel, and is therefore squeezed into its seat (figure 9).
• teeth 80' which constitute the selection tips, are in fact moved in advanced contact position with the heels by the heels themselves that make the toothed wheel rotate.
• the actuating means 30 comprise a piezoelectric sheet, for example of ceramic, suitable for oscillating an end thereof carrying or acting on the selection tip or on the abutment means.
• the new solution of device for making the selection by squeeze does not consist in moving the selection tip upward or downward anymore, as in the prior art, where the tip is constrained to the actuating means.
• the proposed device solution envisages a forward and backward movement (relative to the cylinder) of the tip itself, and using the actuating means to provide an enable signal to interrupt this cycle.
• the selection tip is not mechanically constrained to the actuating device for performing the movement thereof, but slides longitudinally guided or pivoted at the side.
• the selection is made by means of a mechanical device (the abutment means 42; 62) which, once enabled, interferes with the tip preventing the retraction thereof.
• the movement of the abutment means is facilitated by the movement and by the force of the tip itself which auto-hooks and completes the stroke required to reach the resting point thereof.
• the selection is made by interference, that is, arranging a mechanical obstacle so as to prevent the selection tip from retracting by the undemeedle, which as a consequence is squeezed.
• the actuating time that is, of the movement of the abutment means, is equal to about 1 ms and is performed when the lever is in its typical rest condition, that is, all forward against the machine cylinder.
• the resulting selection speed is not determined by the movement or actuating times of the machine, but is directly determined by the speed of rotation of the machine itself.
• the selection speed is not determined by the actuating time of the actuating means anymore, but is determined by the time required to enable the enable signal only.
• the horizontal movement of the selection tip occupies only about half the space required by the selection tips that work in vertical direction, allowing very low actuators with a smaller number of tips.
• Lower selection devices allow lower needle holder cylinders, more compact machines with less inertia and lower energy consumption.
• the tip may also be heavier since it does not affect the actuating time anymore; it can therefore have a larger thickness allowing a better work and less wear of the undemeedle.
• the tip may have a steeper contact profile with the heel and thus be less wide, allowing the construction of narrower selection devices.
• Narrower selection devices allow positioning more actuators around the cylinder allowing the use of more colours, more drops and more works with the stitches.
• the selection device proposed herein does not require the end of the actuating means carrying the selection tip to perform all the stroke required for the movement of the underneedle, as in the current devices, but only a little movement that is used to enable the selection.
• the device according to the invention is influenced by the minimum time required, since with its specific speed it determines the working cycle, the stroke required for the selection, since the heel makes the tip perform the stroke it requires to be selected, and by the weight or shape of the selection tip, since the work or energy required to move the tip itself in its working/non working range is the same that moves the machine mechanics and not that specific that would e needed to actuate the tip itself.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Knitting Machines (AREA)
• Control For Baths (AREA)
• Structure Of Belt Conveyors (AREA)
• Massaging Devices (AREA)

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Citations (4)

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• 2007
  • 2007-10-18 IT ITBS20070159 patent/ITBS20070159A1/it unknown
• 2008
  • 2008-03-20 CN CN201210191969.2A patent/CN102704173B/zh not_active Expired - Fee Related
  • 2008-03-20 CN CN2008801209924A patent/CN101903579B/zh not_active Expired - Fee Related
  • 2008-03-20 WO PCT/IT2008/000184 patent/WO2009050755A1/en active Application Filing
  • 2008-03-20 KR KR1020107010891A patent/KR20100099682A/ko not_active Application Discontinuation

Patent Citations (4)

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