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
  • D04B15/88—Take-up or draw-off devices for knitting products
  • D04B15/90—Take-up or draw-off devices for knitting products for flat-bed knitting machines

Definitions

• the present invention relates to manufacturing of automatic knitting machines, in particular flat-bed or circular-bed knitting machines.
• flat-bed knitting machines are usually equipped with a couple of needle beds, along which a carriage moves longitudinally with alternate motion.
• the carriage bears suitable actuator units that move selectively, according to a prefixed programme, needles which are introduced inside transversal slits made at regular distances along the needle beds.
• the above mentioned actuator units actuate the needles in succession, according to the commands provided by an electronic control unit, programmed with a suitable knitting programme, so as to achieve formation, in succession, of a series of so-called fabric rows.
• Knitting machines need to stretch vertically the fabric being formed.
• the traditional devices used for this purpose generally include one or more rollers placed below the needle beds and parallel thereto. These rollers are designed to clamp and pull the fabric while being formed.
• a known device of this type provides a couple of rollers tangent to each other and rotated in opposite directions, for a preset time interval, at the end of each carriage stroke.
• Suitable cams are designed to close the clamping members in suitable phase relation with formation of the fabric rows, when the slide is in the raised position. Therefore, these clamping members cyclically clamp the fabric, perform a pulling stroke, and then release the fabric.
• the stroke of the holding parts can be varied from a maximum to a minimum, relative to the desired stretching degree that depends on the knitting type and the number of fabric forming operation that can be obtained with a single stroke of the carriage.
• the possibility to increase the stretching is limited to the maximum stroke that can be imparted to the holding parts.
• the above men- tioned device performs an effective stretching action when the manufacturing is of the type includ ⁇ ing one or at most two fabric forming operations for each stroke of the carriage.
• the object of the present invention is to propose an improved device that performs a uniform vertical stretching of fabric in knitting machines, in particular that varies the stretching in accor ⁇ dance with the kind of manufacturing technique and the number of fabric forming operation per carriage stroke.
• a device for the vertical stretching of fabric in an auto ⁇ matic knitting machine in particular a flat-bed knitting machine, which includes two longitudinal needle beds below which the fabric being formed exits, and that further includes a series of clamp ⁇ ing members for the fabric, arranged below the needle beds regularly spaced apart, and respectively consisting of oscillating claws, articulated to a supporting element along a longitudinal axis extend ⁇ ing parallel to the needle beds, a stationary abut ⁇ ment plate cooperating with the claws, and presser plates articulated to the claws along a longitudinal axis and designed to act ela ⁇ tically on a longitudi ⁇ nal roller arranged below the abutment plate and driven to rotate with a continuous motion according to a direction in agreement with the descent of the fabric being formed.
• a slide elements is connected to the support ⁇ ing element and is actuated so as to slide vertical ⁇ ly stepwise with a reciprocating motion, between a raised position, in which the fabric is clamped and a lowered position, in which the fabric i ⁇ released.
• Cam means are provided for rotation of the claws to close the clamping elements, in suitable phase relation with formation of the rows of the fabric, when the slides are located in the raised position.
• Fig. 1 shows a cross-section view of the stretch ⁇ ing device being the subject of the present inven ⁇ tion
• - Figs. 2, 3, 4, and 5 show cross-section views of the subject device in subsequent working steps;
• - Fig. 6 is a perspective detailed view of fabric gripping members of the subject device.
• the two needle beds of a flat-bed automatic knitting machine are indicated with 1 and 2, and a portion of a knitted fabric being formed is indicated with 3.
• the needle beds 1 and 2 feature regularly spaced apart transverse slits, well known in the art, in which the needles 4 are inserted and actua ⁇ ted by respective operative systems.
• the needle beds 1 and 2 are supported by a stationary frame that includes a couple of platforms 5 situated respectively below the needle beds l and 2; the platforms 5 are fixed to the needle beds 1,2 surfaces with interposition of a plurality of spacer elements 6.
• connection plate 8 is fixed to the second platform 5, adjacent thereto, forms a vertical wall extending lengthwise along the machine, below the top of the first needle bed 1 , and supports a an abutment plate 9.
• connection plate 8 bears also a rotating knurled roller 10 (see also Fig. 6) , arranged below the abutment plate 9 and operated, by suitable motor means, with a continuous motion at low speed, ac ⁇ cording to a rotation direction in agreement with the descent of the fabric being formed.
• a vertically sliding angular element 11 is fitted alongside the cross-member 7.
• Suitable pads 12 made of antifriction material, designed to reduce the sliding friction, are placed between the angular element 11 and the cross-member 7.
• the pads 12 are inserted in corresponding openings made on the angular element 11 and are blocked by a plate 13 placed longitudinal to the same angular element 11.
• a series of prongs 15, suitably spaced out, are articulated to the angular element 11 by related hinges 14.
• the prongs 15 have an upper portion 15a, designed to face the cross-member 7, and a lower portion 15b facing downwards; the downward facing portion 15b is located below the angular element 11.
• Patent No. 5.271.250 for each prong 15 there is a lever 16 connected therewith and subjected to the action of a cam 17, so that the same prong 15 is made to oscillate; this cam 17 is made up of a cam shaft rotating about a horizontal axis longitudinal to the machine.
• the hinge 14 features two seats for receiving of respective pins 18 and 19 for the pivotal connection to the angular element 11 and the lever 16; the pins 18,19 have horizontal axes that are parallel to the machine.
• the lever 16 protrudes over the cam shaft 17 in a kind of beak 16a.
• the lever 16 normally rests against the downward facing part 15b of the prong 15 being held in position by elastic action of a spring - 7 -
• the spring 20 is retained by a knob 21 inser ⁇ ted in the above mentioned housing of the lever 16; the head of this knob 21 rests against the lower surface of the downwards facing portion 15b of the prong 15.
• each prong 15 there is situated a clamping member 22, aimed at cooperating with the stationary abutment plate 9 for holding the fabric 3 to be stretched.
• the clamping member 22 includes a claw 23 equipped with couples of teeth 23a arranged along the upper edge.
• the presser plates 25 push lightly the roller 10, due to the elastic action exerted by a spring 26, that urges the prong 15.
• the presser plates 25 On their surface turned toward the roller 10, the presser plates 25 feature a series of vertical grooves 27; these grooves 27 are designed to receive the threads that separate the rows of the fabric 3 being formed, extended in known way in direction parallel to the same fabric.
• the presser plates 25 have a section 25a bent toward the prong 15.
• the presser plates 25 In correspondence with the ends of the needle beds 1,2, there is a pair of symmetrical slides 2S, only one of which can be seen in the drawing; the slides 28 are fitted in known way to the angular element 11.
• Each slide 28 has a rack profile 29 that meshes with a pinion 30, supported rotatably by the stationary frame 31 of the machine and designed to be stepwise operated by related drive parts .
• the slide 28 is guided by a counter-roller 32, also supported rotatably by the stationary frame 31 of the machine.
• the action of the rack 29 is also balanced by a spring 33 suspended vertically on the frame 31 and hooked to a pin 34 protruding trans- versally to the lower end of the slide 28.
• the presser plates 25 follow the downward movement imposed to the claws 23 by the slides 28. Due to reciprocal adaptations, the lower ⁇ ing of the claws 23 determines also rotation of the presser plates 25 with the roller 10 acting as a pin. This rotation carries the bent section 25a of the presser plates 25 to strike against the prongs 15, so as to form with the latters one rigid body capable of clamping with force the fabric to the rotating knurled roller 2 0 (Fig. 4) . The action of the presser plates 25 causes also a limited rotation of the prongs 15 that rotate with respect to the levers 16, kept in contact with the cam shaft 17.
• This rotation determines the return of the claws 23 with the consequent separation of the teeth 23a from the abutment plate 9 and the release of the fabric 3 (see again Fig. 4) .
• the knurled roller 10 can continue the stretching action of the fabric 3, if this is necessary.
• the device allows to vary operation in relation with the length of the rows and the number of the fabric forming operations per each carriage stroke.
• the stretching steps performed by the claws 23, illustrated previously are suffi ⁇ cient in the machines with one or two fabric forming operations, while further stretching performed by the knurled roller 10, during the descent stroke, is advantageously used in the machines with many fabric forming operations, such as three or four opera ⁇ tions .
• the elastic clamping thrust exerted on the fabric 3 is supplied by the springs 20 carried by the levers 16 and acting on the prongs 15.
• the presser plates 25, in conjunction with the roller 10, can alsc maintain the fabric 3 taut during the subsequent 3tep, in which the slides 28 rise again (Fig. 5) .
• a further rotation of the cam shaft determines the disengagement of the levers 16, that return to form one body with prongs 15.
• the rise does not bring the teeth 23a of the claws 23 to touch the stationary abutment plate 9, since the springs 26 push elastically the presser plates 25 so as to touch a knurled roller 10, thus allowing a light return rotation of the prongs 15, that keeps the same prongs 15 suitably distanced from the abutment plate 9.
• the device in ques- tion involves the creation of a sequence of successive ⁇ sive clamping steps for the fabric 3 performed by - li ⁇
• the clamping members 22 are normally activa ⁇ ted when the carriage, that slides along the needle beds 1, 2, inverts its stroke.
• the fabric 3 is kept taut by the presser plates 25 that clamp it elastically to the knurled roller 10, operated with a continuous motion at a low speed.
• the roller 10 exerts a constant traction action, preventing the fabric from elastic returning.
• the rotating knurled roller 10 allows to continue stretching of the fabric.
• the fabric 3 is kept taut by the presser plates 25 and the rotating roller 10.
• the described device makes it possible to vary the stretching in relation to the number of fabric forming operations and the type of manufacturing.
• the device is also simple to build, thus reducing considerably the costs of production and maintenance.
• the device subject of this invention, has been proposed associated with a flat-bed machine, for example for knit-wear.
• This device can be usefully adopted with a circular type knitting machine, or with any kind of machine that produces fabric of whatever kind.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Knitting Machines (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11340216

Family Applications (1)

Country Status (7)

Cited By (4)

Families Citing this family (1)

Citations (4)

• 1995
  • 1995-01-23 IT IT95BO000016A patent/IT1278165B1/it active IP Right Grant
• 1996
  • 1996-01-18 JP JP8522752A patent/JPH10512930A/ja not_active Ceased
  • 1996-01-18 WO PCT/IB1996/000041 patent/WO1996023094A1/en active IP Right Grant
  • 1996-01-18 DE DE69603254T patent/DE69603254T2/de not_active Expired - Fee Related
  • 1996-01-18 ES ES96900153T patent/ES2133923T3/es not_active Expired - Lifetime
  • 1996-01-18 EP EP96900153A patent/EP0805885B1/en not_active Expired - Lifetime
  • 1996-01-18 BR BR9606775A patent/BR9606775A/pt not_active Application Discontinuation

Patent Citations (4)

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