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
• • D—TEXTILES; PAPER
  • D04—BRAIDING; LACE-MAKING; KNITTING; TRIMMINGS; NON-WOVEN FABRICS
  • D04B—KNITTING
  • D04B35/00—Details of, or auxiliary devices incorporated in, knitting machines, not otherwise provided for
  • D04B35/34—Devices for cutting knitted fabrics

Definitions

• the present invention relates to a method and an apparatus for stretching and collecting a knitted fabric produced by circular knitting machines comprising the phases of substantially flattening a tubular piece coming from the circular machine, progressively cutting the flattened tubular piece along a longitudinal generatrix, spreading the piece and its lateral edges obtained from its cutting, stretching the spread piece in a single layer of fabric, and collecting the stretched piece into a roll.
• the apparatus comprises a support frame positioned inferiorly to said circular knitting machine and able to rotate integrally with its cylinder, means for substantially flattening the tubular piece coming from the circular machine, cutting means positioned downstream of said flattening means and able to cut the tubular piece longitudinally along a generatrix, means for opening and stretching the cut piece in a single layer of fabric, and an assembly for collecting the piece stretched in a single layer.
• the aforementioned US Patent provides for positioning a walkway platform around the circular machine, above the apparatus for stretching and collecting the fabric or, alternatively, for inserting the latter in a pit obtained in the ground of the factory. It is evident that in the first case access to the circular machine is not immediate, since it is necessary to climb on the walkway, whilst in the second case additional operating costs are incurred both for removing the piece collected in a roll and for maintaining the apparatus and the pit.
• the technical task constituting the basis for the present invention is to provide a method and an apparatus for stretching and collecting the knitted fabric produced by circular knitting machines able substantially to overcome the aforementioned drawbacks.
• an important aim of the invention is to devise a method and an apparatus for stretching in a single layer and collecting a knitted fabric produced in a tubular piece which allow to maintain substantially unaltered, relative to the traditional technique for collecting the fabric in double layer, the positioning of the circular knitting machine in terms of height.
• Another important aim of the invention is to provide a method and an apparatus which allow a better and more delicate stretching in a single layer of a knitted fabric produced in tubular piece.
• a further aim is to devise a method and an apparatus which favour the employment of loading and transporting trucks, also automated, for the removal of the fabric collected in a roll or in superposed layers.
• Yet another aim of the invention is to make available an apparatus which is easily converted from the function of stretching width-wise, i.e. in a single layer, a tubular piece to the traditional function of applying traction without cutting and widening the tubular piece itself.
• Figure 1 shows a side elevation view of the apparatus
• Figure 2 is a perspective view of the apparatus of Figure 1;
• Figure 3 presents a partial and schematic perspective view of the main components of the apparatus; - Figure 4 shows a view similar to the one of Figure 3 highlighting the successive operative phases whereto a circular fabric is subjected.
• It comprises a support frame 2 positioned inferiorly to a known circular knitting machine 3 provided for producing, in correspondence with a cylinder 4, of knitted fabric in tubular piece 5.
• the support frame is able to rotate integrally with the cylinder 4 about a vertical central axis 6 and is positioned internally to a fixed structure 7 which sustains both the frame 2 itself and the circular machine 3.
• the means 8 comprise a piece-widening frame 9, known in itself, able progressively to modify the cylindrical shape of the piece by substantially flattening it along a diametrical direction thereof and a pair of parallel piece-pressing roller 10 suitably distanced from each other and externally delimiting the piece.
• cutting means 11 able progressively to cut the tubular piece 5 along a generatrix, and means 12 for opening and stretching the cut piece, able to widen it in a single layer 5a.
• the opening and stretching means 12 comprise two rollers 13 for spreading the piece 5 and its lateral edges 5b obtained from the cutting and a roller 14 for transmitting the stretched piece.
• the spreading rollers 13 are arranged according to diverging lines inclined downwards and developing starting from upper extremities 13a mutually approached and positioned in an area of the piece opposite said cut generatrix. More in detail the upper extremities 13a are positioned in opposition to the cutting means 11 and substantially level therewith, until reaching inferiorly, with lower extremities 13b, a first edge area 2a of the support frame 2 laterally displaced relative to the central vertical axis of the knitting machine.
• the spreading rollers 13 are hinged, in correspondence with their approached upper extremities 13a, to a first terminal portion 15a of a support body 15 integral to the support frame 2 and have the lower extremities 13b able to be fastened at an adjustable mutual distance to an arched base element 16 also integral with the frame 2.
• the spreading rollers 13 can be mounted idle on the support roller 2, but preferably and advantageously are provided with independent motors 13c the further to favour the stretching of the piece in single layer.
• the direction of rotation imposed by the motors to the rollers is preferably opposite the direction of advance of the piece to enhance the stretching effect on the piece.
• the first terminal portion 15a of the support 15 extends externally with a rotating element 17 with curved profile able to guide the piece immediately below the parallel rollers 10 favouring its sliding in the critical area of increased tension opposite to the cut generatrix.
• the rotating element 17 can be constituted by a wheel or a ball. Alternatively to the rotating element, an oscillating arm with curved extremity, tensioned by a spring, can be provided.
• the cutting means 11 which, advantageously, comprise a rotating blade 18, a blade guide 19 and a motor 20 for supporting and controlling the blade, available in a position adjustable on the support body 15 itself to enable varying, according to operative requirements, the distance of the rotating blade 18 from the central axis 6. Also the position of the rotating element 17 can be adjusted, since it is mounted on a bar 17a able to be fastened by means of screws to corresponding slots obtained in the support body 15.
• the set of driving rollers 21 comprises a central tensioning roller 21a and two lateral contrasting rollers 21b.
• the set of driving rollers 21 is controlled by a motor 21c independently of the means for actuating the other rollers or of the means that serve other functions of the apparatus.
• a set 22 Downstream from the driving rollers set 21, in correspondence with a second edge area 2b of the support frame 2 and laterally offset relative to the central axis 6, is positioned a set 22 for collecting the piece stretched in a single layer into a roll.
• a known device can be provided, suitable for collecting the piece in superposed layers.
• a first roller for tensioning the piece in the transverse direction 23 having two grooved portions helically wound in opposite directions able to contrast the tendency of the bands of the piece itself that are proximate to the • lateral edges 5b to curl themselves longitudinally.
• a piece-presser roller 23a positioned in the vicinity of the transverse tensioning roller 23 to increase the winding angle of the piece about the transverse tensioning roller with the consequent increase of the effectiveness of the action of the helically grooved portions on the edges of the piece.
• the piece-presser rollers 23a and 24a can be adjusted both horizontally towards and away from the respective transverse tensioning rollers 23, and vertically to determine a greater or lesser winding of the piece about the transverse tensioning roller 23.
• the transverse tensioning rollers 23 and 24 are equipped with motors 23b and 24b independent from the other functions of the machine to have speeds greater than that of the prior art, with the consequent improvement in the stretching of the edges of the piece which tend to become curled up.
• the support frame 2 has a pair of horizontal cross members 27 oriented orthogonally to said driving rollers set 21 and provided with supplementary seats 28 (Fig. 2) for the extremities of the piece presser rollers 10.
• the seats 28 allow a simple and rapid re-positioning of the piece-presser rollers 10 themselves to 90° when, alternatively to the cutting and the width-wise opening of the tubular fabric, its stretching and traditional collection in two superposed layers are required.
• proximity sensors 29 or contact oscillators have been shown schematically, for arresting the apparatus if the operator should approach it excessively, or even come in contact with the rotating support frame 2.
• the sensors 29 are positioned at least in correspondence with the edges of the rotating support frame .
• the operation of an apparatus described above in a prevalently structural sense is as follows.
• the tubular piece 5 coming from the cylinder 4 is gradually flattened by the piece-spreader frame 9, by the parallel piece-presser rollers 10 and by the blade guide 19.
• the flattened tubular piece tensioned longitudinally by the driving roller set 21, is cut by the cutting means 11 along one of its generatrices whilst, in correspondence with the opposite generatrix, it slides on the rotating element 17 which prevents deflections and the formation of creases.
• the cut piece is progressively widened and stretched by the spreading rollers 13, until it passes, completely open, on the transmission roller 14.
• the single-layer fabric continues along a substantially horizontal path, moving from the first edge area 2a of the support frame 2, where the transmission roller 14 is located, to a second, opposite, edge area 2b where the set 22 for collecting in a roll or possibly in superposed layers.
• the transverse tensioning rollers 23 and 24 maintain the knitted fabric perfectly flat, preventing it from curling in correspondence with the edges.
• the invention implements a new method which also forms an integral part of the present patent.
• This spreading operation is performed gradually according to downwards-inclined lines developing substantially from the height of the cutting area until reaching inferiorly a first position laterally offset relative to the central vertical axis of the knitting machine. In correspondence with this first position, the stretching of the piece spread in a single layer of fabric is completed.
• the path of the piece continues substantially horizontally and reaches a second position laterally offset relative to the central axis, opposite to the first position itself.
• the stretched piece is collected in a roll or in superposed layers.
• the piece In the substantially horizontal segment of the path of the piece lying between said first and second position, the piece is subjected to traction for its controlled advance through all the operative phases illustrated downstream of the cylinder of the knitting machine.
• the stretched piece is subjected to two tensioning operations in the transverse direction able to contrast the tendency of the edge bands to curl themselves.
• the apparatus and the method obtain a path of the piece in the cutting and opening phases and subsequently of the stretched piece which exploits to the fullest extent the horizontal space underneath the cylinder of the knitting machine.
• the vertical dimension of the apparatus is therefore limited and hence the height and accessibility of the overlying knitting machine are practically unchanged relative to the traditional technique without width-wise opening.
• the ease of access to the cylinder working plane is determined by the fact that the driving, collecting and transverse tensioning rollers are situated on a single plane positioned at the base of the machine. This alignment of the rollers below leaves room in the high end of the machine and allows to incline the spreader rollers, thereby facilitating the operator's task when he or she needs to approach the operative organs of the circular machine.
• the diameter of the ring 30 supporting the thread feeders 31 has also been increased, making it substantially equal to the dimensions of the base. In this way the feeders are moved away from the axis of the machine and closer to the operator.
• the architecture of the machine allows to position laterally the set for collecting the stretched fabric in a roll or in superposed layers, thereby facilitating the positioning of a truck, which can also be automated, for the extraction and transport of the wound piece.
• the length of the widening segment of the knit obtained from the original disposition of the spreader rollers and the cut with rotating blade allow to obtain a gradual and delicate opening of the knitted piece itself and to maintain a ' regular tensioning both in the phase of forming the knit and in the subsequent path towards the set for collecting in a roll.
• the apparatus according to the invention has high operative flexibility as it allows easily and rapidly to shift - as need be - to traditional tensioning and collecting in a roll without cutting and widening the piece.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Knitting Machines (AREA)
• Treatment Of Fiber Materials (AREA)
• Knitting Of Fabric (AREA)
• Spinning Or Twisting Of Yarns (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=11346292

Family Applications (1)

Country Status (11)

Cited By (13)

Families Citing this family (14)

Citations (3)

• 1999
  • 1999-02-23 IT IT1999BS000016A patent/IT1309184B1/it active
• 2000
  • 2000-02-18 ES ES00909622T patent/ES2241582T3/es not_active Expired - Lifetime
  • 2000-02-18 PT PT00909622T patent/PT1155176E/pt unknown
  • 2000-02-18 JP JP2000601236A patent/JP2002538316A/ja active Pending
  • 2000-02-18 DE DE60019899T patent/DE60019899T2/de not_active Expired - Lifetime
  • 2000-02-18 CN CNB00804080XA patent/CN1189614C/zh not_active Expired - Fee Related
  • 2000-02-18 AU AU31900/00A patent/AU3190000A/en not_active Abandoned
  • 2000-02-18 AT AT00909622T patent/ATE294885T1/de not_active IP Right Cessation
  • 2000-02-18 KR KR1020017009806A patent/KR100700225B1/ko not_active IP Right Cessation
  • 2000-02-18 WO PCT/IT2000/000052 patent/WO2000050678A1/en active IP Right Grant
  • 2000-02-18 EP EP00909622A patent/EP1155176B1/en not_active Expired - Lifetime

Patent Citations (3)

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